WO2008076399A2 - Apparatus and method comprising deformable lens element - Google Patents

Apparatus and method comprising deformable lens element Download PDF

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Publication number
WO2008076399A2
WO2008076399A2 PCT/US2007/025707 US2007025707W WO2008076399A2 WO 2008076399 A2 WO2008076399 A2 WO 2008076399A2 US 2007025707 W US2007025707 W US 2007025707W WO 2008076399 A2 WO2008076399 A2 WO 2008076399A2
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WO
WIPO (PCT)
Prior art keywords
deformable
force
focus
lens
lens element
Prior art date
Application number
PCT/US2007/025707
Other languages
French (fr)
Other versions
WO2008076399A3 (en
Inventor
Ynjiun P. Wang
Chen Feng
William H. Havens
Jianhua Li
Original Assignee
Hand Held Products, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/781,901 external-priority patent/US8027096B2/en
Priority claimed from US11/897,924 external-priority patent/US7813047B2/en
Application filed by Hand Held Products, Inc. filed Critical Hand Held Products, Inc.
Priority to JP2009541411A priority Critical patent/JP2010513952A/en
Priority to CN2007800514041A priority patent/CN101632030B/en
Priority to EP07862981A priority patent/EP2092378A2/en
Publication of WO2008076399A2 publication Critical patent/WO2008076399A2/en
Publication of WO2008076399A3 publication Critical patent/WO2008076399A3/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/12—Fluid-filled or evacuated lenses
    • G02B3/14—Fluid-filled or evacuated lenses of variable focal length
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/0875—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more refracting elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/028—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
    • G02B7/38—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals measured at different points on the optical axis, e.g. focussing on two or more planes and comparing image data
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/06—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the phase of light

Definitions

  • the invention relates to a lens element for incorporation into an optical imaging system and specifically to an apparatus and method comprising a deformable lens element
  • Variable lenses e g , multiple focus lenses and ?oom lenses have traditionally employed one or more non-deformable (; e , rigid such as glass or polycarbonate) lens elements which are moved along an imaging axis by forces often supplied by a motor
  • motorless electro-responsive lens elements have attracted increased attention of researchers and designers of optical systems
  • One type of motorless electro-responsive lens element is the "fluid lens" lens element which generally includes a rigid or elastomeric membrane filled with one or more fluids having indices of refraction greater than 1
  • Fluid lens element technology has attracted the attention of many designers of optical systems who generally see traditional solid lens elements and motor equipped systems as bulky and energy hungry
  • the proposals for fluid lens elements there have been proposed various methods for varying an optical property of a fluid lens element for integration into an optical system Where fluid lens elements have been proposed, the proposed alternatives for varying optical properties of such lens elements can be categorized into two broad categories electro wetting and fluid injection
  • a fluid lens element having at least two immiscible fluids and a voltage is applied to the fluid lens element A surface tension of the fluid lens element changes as a result of the voltage being applied, bringing about a change in the curvature of an interface between the at least two fluids
  • a pump is provided adjacent a fluid lens element which pumps in and draws out fluid from the lens element As fluid is pumped in and drawn out of the lens element, optical properties of the lens element change
  • electro wetting one problem that has been noted is that the electrical current repeatedly flowing through the lens element tends to alter the characteristics of the lens element over time, rendering any system in which the lens element is employed unreliable and unpredictable
  • electro wetting normally involves providing two types of fluids As the reference index difference between the fluids is small, the power of the lens element is reduced
  • the pumps for providing such fluid injection are necessarily complex and intricate making a reasonably costly system and acceptable miniaturization difficult to achieve
  • a fluid lens sometimes also referred to as an adaptive lens, comprises an interface between two fluids having dissimilar optical indices
  • the shape of the interface can be changed by the application of external forces so that light passing across the interface can be directed to propagate in desired directions
  • the optical characteristics of a fluid lens such as whether the lens operates as a diverging lens or as a converging lens, and its focal length, can be changed in response to the applied forces
  • Additional methods of controlling the operation of fluid lenses include the use of liquid crystal material (Nishioka, U S Patent No 6,437,925), the application of pressure (Widl, U S Patent No 6,081 ,388), the use of elastome ⁇ c materials in reconfigurable lenses (Rogers, U S Patent No 4,514,048), and the uses of micro-electromechanical systems (also known by the acronym "MEMS") (Gelbart, U S Patent No 6,747,806)
  • Lenses and lens systems may be fixed or variable, and a lens system may contain fixed and/or variable lenses
  • a fixed lens system, and a fixed lens have a fixed or static focal point, that is, the focal length and orientation of the optical axis do not change
  • a non-deformable, solid lens rigidly attached to an optical system would, in and of itself, be fixed, and if the lens system did not contain any other elements capable of changing the focal length and/or orientation of the optical axis of the lens system, the lens system would similarly be fixed
  • a conventional pair of eyeglasses is such a fixed lens system
  • Each lens in the eyeglasses is a fixed lens because it is incapable of changing its focal length or the orientation of its optical axis Because the eyeglasses do not contain any additional lenses or other methods to effect such a change, the eyeglasses themselves are a fixed lens system
  • variable lens in contrast, is inherently variable, and any lens system incorporating it is likewise inherently variable Fixed lenses are generally composed of non-deformable materials such as glass or plastic, or, if composed of an elastic or deformable material, are part of a lens system that does not include any method for causing them to stretch, compress, bend, or otherwise change shape or deform
  • a variable lens may be composed of elastic or deformable materials, and, where it is desired that the lens be capable of returning to its original state after being stretched, compressed, bent, or otherwise deformed, will be composed of one or more elastically deformable elements
  • a number of types of force elements may be used to provide the force required to change the shape of the interface in a variable lens Fluid lenses using technology that employs electrical signals to control the operation of the fluid lens have been described in Matz, U S Patent No 2,062,468, Berge et al , U S Patent No 6,369,954, Onuki et al , U S Patent No 6,449,081 , Tsubo
  • Micropump control systems may also be used to control fluid lenses, as described for example in
  • Such systems may involve a chamber or container of fluid in force communication with a deformable membrane
  • a deformable membrane There may be a single such chamber, which contains or is acted on by a mechanical force element, such as a piston, to push fluid towards, or draw it away from, the membrane
  • a mechanical force element such as a piston
  • the mechanical force element may be powered by electricity, the force actually acting on the interface in order to change its shape is mechanical
  • Additional methods of controlling the operation of fluid lenses include the use of liquid crystal material (Nishioka, U S Patent No 6,437,925), the application of pressure (Widl, U S Patent No 6,081 ,388), the use of elastomeric materials in reconfigurable lenses (Rogers, U S Patent No 4,514,048), and the uses of micro-electromechanical systems (also known by the acronym "MEMS") (Gelbart, U S Patent No 6,747,806)
  • An apparatus comprising a deformable lens element can be provided wherein a deformable lens element can be deformed to change an optical property thereof by the impartation of a force to the deformable lens element
  • Fig 1 is an exploded assembly view of a focus apparatus (focusing module) including a deformable lens element that is arranged in such manner that the deformable lens element can be deformed to vary an optical characteristic of the lens element
  • Fig 2 is an assembled view of the focus apparatus of Fig 1 , showing the apparatus in a state in which the deformable lens element includes a convex lens surface
  • Fig 3 is an assembled view of the focus apparatus of Fig 1 showing the apparatus in a state in which the deformable lens element includes a nominally planar surface
  • Fig 4 is a cutaway side view showing an alternative embodiment of the deformable lens element -3
  • Fig 5 is a cutaway side view showing an alternative embodiment of the deformable lens element of Figs 1 -3
  • Fig 6 is an exploded perspective assembly view of a focus apparatus incorporating a dielectric electro-active polymer actuator
  • Fig 7 is an exploded perspective view of a focus apparatus incorporating a deformable lens element and a hollow stepper motor
  • Fig 8 is a cutaway side view of the focusing apparatus as shown in Fig 7
  • Fig 9 is a perspective view illustrating operation of a hollow stepper motor in one embodiment
  • Fig 10 is an exploded perspective assembly view of a deformable lens element in one embodiment
  • Fig 1 1 is an assembled cutaway side view illustrating the deformable lens element shown in Fig
  • Fig 12 is a detailed cutaway side view illustrating a highlighted section of the deformable lens element as shown in Fig 10
  • Fig 13 is an assembled side view illustrating a deformable lens element having a pair of opposing light entry and light exit lens surfaces that comprise respective deformable membranes
  • Fig 14 is an assembled side view showing an embodiment of a focusing apparatus incorporating a deformable lens element as shown in Fig 13, a first actuator for deforming a first deformable lens surface of the deformable lens element and a second actuator for deforming a second deformable lens surface of the deformable lens element
  • Fig 15 is an assembled side view of a deformable lens element incorporating a resiliently deformable material member
  • Fig 16 is an assembled side view of another embodiment of a deformable lens element incorporating a resiliently deformable material member
  • Fig 17 is a side view of a deformable lens element including a resiliently deformable material member and a protective coating thereon
  • Fig 18 is an assembled side view of a focus apparatus having a deformable lens element and a pair of flexible member actuators, wherein the flexible members are adapted to substantially conform to the shape of the deformable lens element
  • Fig 19 is an exploded perspective assembly view of a focus apparatus as shown in Fig 18
  • Fig 20 and Fig 21 are force impartation diagrams illustrating exemplary force impartation positions for a deformable lens member, showing front views of a deformable lens element looking in the direction of an imaging axis
  • Figs 22-24 are side schematic views illustrating various lens assemblies incorporating at least one deformable lens element
  • Fig 25 is an electrical block diagram of an exemplary imaging terminal in which a deformable lens element can be incorporated
  • Fig 26 is a timing diagram for illustrating exemplary aspects of operation of an imaging terminal in one embodiment
  • Fig 27 is a flow diagram illustrating an auto-focus algorithm that can be executed by an imaging terminal in one embodiment
  • Fig 28 is a front perspective view of a hand held mobile terminal having a hand held housing in which the components as shown in Fig 25 can be incorporated and supported by
  • Fig 29 is an exploded view of one embodiment of a focus module
  • Fig 30 is the focus module of Fig 29 as viewed from the right side
  • Fig 31 is the focus module of Fig 29 as viewed from the left side
  • Figs 32 and 33 show the effect of pressure exerted on the focus membrane in a direction substantially normal to the plane of the focus membrane
  • Figs 34 and 35 show the effect of pressure exerted on the focus membrane in a direction substantially parallel to the plane of the focus membrane
  • Fig 36 is a view of the deforming element
  • Fig 37 shows the focus fluid having a non-symmetric meniscus
  • Fig 38 shows a cylindrical component of the focus module
  • Figs 39 is a side perspective showing convex distortion of the top surface of a cylinder having a fluid interior volume in response to a reduction in height of the cylinder
  • Fig 40 is a side perspective showing convex distortion of the top surface of a cylinder having a fluid interior volume in response to a reduction in diameter of the cylinder
  • Figs 41 and 42 illustrate the deforming element as it deforms from the initial shape shown in Fig
  • Fig 43 shows the deforming element assuming a funnel-like shape
  • Figs 44-47 show various ranges or directions of motion for the deforming element
  • Figs 48 and 49 show a bi-convex electro-actuated polymer membrane lens
  • Fig 50 shows a lens assembly incorporating multiple deformable focus membranes
  • Figs 51 and 52 show a conventional lens with an electro-actuated polymer deforming element
  • Fig 53 is a diagram showing a reader
  • Fig 54 is a diagram showing the control circuitry of the reader of Fig 53 in greater detail
  • Fig 55 is a block diagram of an optical reader showing a general purpose microprocessor system that is useful with various embodiments of the invention
  • Fig 56 is a flow chart showing a process for operating a system having an adjustable focus system comprising feedback
  • Fig 57 is a flow chart showing a process for operating a system having an adjustable focus system that does not comprise feedback
  • Fig 58 is a circuit diagram showing a commutating power supply for a fluid lens system
  • Fig 59 is a timing diagram showing a mode of operation of the commutating power supply of Fig
  • Figs 60 and 61 are drawings of hand held readers
  • Fig 62 is a diagram of a handheld reader in communication with a computer
  • Fig 63 is a flow chart of a calibration process useful for calibrating apparatus embodying features of the invention
  • Fig 64 is a diagram showing calibration curves for a plurality of hand held readers
  • Fig 65 is a diagram showing an embodiment of a power supply suitable for use with hand held readers
  • Fig 66 is a timing diagram illustrating a mode of operation of a hand held reader
  • Figs 67-69 are cross-sectional drawings showing a fluid lens with a mount comprising an elastomer for a hand held reader
  • Fig 70 is a diagram illustrating a prior art variable angle prism
  • Fig 71 is a cross-sectional diagram of a prior art fluid lens that is described as operating using an electro-wetting phenomenon
  • Fig 72 is a cross sectional diagram 2400 showing an embodiment of a fluid lens configured to allow adjustment of an optical axis
  • Fig 73 is a plan schematic view of the same fluid lens
  • Fig 74 is a schematic diagram showing the relationships between a fluid lens and various components that allow adjustment of the optical axis direction
  • Fig 75 is a schematic diagram of an alternative embodiment of a fluid lens
  • Fig 76 is a schematic diagram of an alternative embodiment of a distributor module
  • Fig 77 is a schematic diagram showing the relationship between a fluid lens and a pair of angular velocity sensors
  • Figs 78-82 are cross-sectional diagrams of another prior art fluid lens that can be adapted for use according to the principles of the invention
  • Fig 83 is a schematic block diagram showing an exemplary driver circuit
  • Figs 84 and 85 are diagrams that show an LED die emitting energy in a forward direction through a fluid lens
  • Figs 86, 87 and 88 show diagrams of a laser scanner comprising a laser 31 10, a collimating lens
  • Fig 89 is a schematic diagram of an apparatus having a membrane
  • Fig 90 is a schematic diagram of the apparatus of Fig 89 after assuming a convex shape
  • Fig 91 is a schematic diagram of an apparatus having a container and a fluid component
  • Fig 92 is a schematic diagram of the apparatus of Fig 91 in an alternative state
  • Figs 93-96 are schematic views of a deformable member illustrating locations of force elements in alternative embodiments
  • Fig 97 is a schematic diagram of an apparatus having a pressure element
  • Fig 98 is a schematic diagram of the apparatus of Fig 97 in an alternative state
  • Fig 99 is a schematic diagram showing an alternative embodiment of an apparatus having a pressure element
  • Fig 100 is a schematic diagram showing an alternative embodiment of an apparatus having a pressure element
  • Fig 101 is a schematic diagram of an apparatus having a piston
  • Fig 102 is a schematic diagram of an apparatus having a piston in an alternative embodiment
  • Fig 103 is a schematic diagram having a primary fluid container and a secondary fluid container
  • Fig 104 is a schematic diagram of an apparatus having a secondary fluid container in another embodiment
  • Fig 105 is a schematic diagram for illustrating directions of forces that can be applied to an apparatus
  • Fig 106 is a schematic diagram illustrating a shape of a pressure element
  • Figs 107- 1 10 are schematic diagrams illustrating alternative shapes for a pressure element
  • Fig 1 1 1 is a schematic diagram showing an apparatus having a pressure element
  • Fig 1 12 is a schematic diagram shown an apparatus having a pressure element in an alternative embodiment
  • Fig 1 13 is a schematic diagram illustrating the apparatus of Fig 1 10 in an alternative state
  • Fig 1 14 is a schematic diagram illustrating the apparatus of Fig 1 13 in an alternative state
  • FIG. 15 is a schematic diagram of an apparatus having a pressure element that applies a force in a radial outward direction
  • Fig 1 16 is a schematic diagram of the apparatus of Fig 1 15 in an alternative state
  • Fig 1 17 is a schematic diagram of an apparatus having a pressure element that can apply particularly opposing forces
  • Fig 1 18 is a schematic diagram of an apparatus having a deformable member
  • Fig 1 19 is a schematic diagram of an apparatus having an alternative fluid element
  • Fig 120 is a schematic diagram of an apparatus having a plurality of discrete force elements
  • Fig 121 is a schematic diagram of an apparatus having a voice coil in one embodiment
  • Fig 122 is a schematic diagram of an apparatus having a voice coil in another embodiment
  • Fig 123 is a schematic diagram of an apparatus having a voice coil in another embodiment
  • Fig 124 is a schematic diagram of an apparatus having a voice coil in another embodiment
  • Fig 125 is a schematic diagram of the apparatus of Fig 124 in a first state
  • Fig 126 is a schematic diagram of the apparatus of Fig 124 in a second state
  • Fig 127 is a schematic diagram of an apparatus having a plurality of deformable surfaces in one embodiment
  • Fig 128 is a schematic diagram of an apparatus having a plurality of deformable surfaces in another embodiment
  • Fig 129 is a schematic diagram of an apparatus having a boundary element
  • Fig 130. is a schematic diagram of an apparatus having a boundary element in another element
  • Fig 131 is a schematic diagram of an apparatus having a convex surface
  • Fig 132 is a schematic diagram of an apparatus having a housing
  • Figs 133 and 134 are drawings of hand held readers that embody features of the invention
  • Fig 135 is a schematic diagram showing the relationship between a variable lens and various components that allow adjustment of the optical axis direction, all according to principles of the invention
  • Fig 136 is a schematic diagram showing the relationship between a variable lens and a pair of angular velocity sensors, according to principles of the invention
  • a deformable lens element for incorporation into an optical imaging system, wherein a force can be imparted to a surface of the deformable lens element for varying of an optical property of the lens element
  • a method for varying an optical property of an optical imaging system including the steps of incorporating a deformable lens element into an optical imaging system, and imparting a force to a surface of the lens element for varying an optical property of the lens element
  • the described deformable lens element apparatus and method provide a number of advantages For example, relative to presently available optical systems incorporating exclusively non-deformable (rigid) lens elements, the presently described apparatus and method provides significant changes in optical properties while significantly reducing the amount of movement of a lens element required to produce the desired change in optical property (e g , focal length) By significantly reducing the amount of movement of a lens element for producing a desired change in optical property, the described apparatus and method facilitate increased miniaturization of an imaging system, and decreased energy consumption of a designed optica! system
  • the above advantages are provided in a highly reliable, easily manufactured optical system that does not exhibit the reliability and manufacturing complexity disadvantages associated with previously proposed electro wetting and fluid injection fluid lens based optical systems
  • a deformable lens element 10 is provided by the combination of deformable membrane 3, spacer element 2, and boundary element I which can be provided by a piece of non-deformable glass, and a focus fluid (not shown) or other deformable substance (e g , a resiliency deformable volume) having an index of refraction greater than I
  • the focus fluid or other deformable substance can be disposed within cavity 8 (as seen in Figs 2 and 3) defined by the combination of deformable membrane 3, spacer element 2, and transparent boundary element 1 as seen in Figs 2 and 3
  • the remaining elements are provided to apply a force to an external surface of lens element 10 Referring to the specific embodiment of Fig 1 , there is provided a pressure element
  • deformable lens element 10 For varying the optical characteristics of deformable lens element 10, voltage can be applied to the electrical contacts of first conductor element 6a and second conductor element 6b to cause bending of tab-like elements 5a As indicated by the assembled form side views of Figs 2 and 3, tab-like elements 5a can be arranged to engage pressure element 4 so that when tab-like elements 5a bend toward deformable membrane 3, pressure element 4 applies a force to an external surface of deformable membrane 3 As is indicated by the views of Figs 1 -3, deformable lens element 10 can include a generally circle shaped surface provided in the embodiment shown by deformable membrane 3 and can include an axis 15 intersecting centers of opposing lens surfaces (provided in the embodiment shown by the exterior surfaces of membrane 3 and boundary element 1 ) Further, pressure element 4 can be ring-shaped so that pressure element 4 can apply a force generally in a direction coextensive with axis 15 at a plurality of points spaced apart from and peripherally disposed about axis 15 of lens element 10 Appa
  • apparatus 100 has two states, namely, a "power off state in which tab-like elements 5a bias pressure element 4 toward membrane 3 to cause membrane 3 to bulge to define a convex lens surface and a "power on” state depicted in Fig 3 in which tab-like elements 5a pull pressure element 4 away from deformable membrane 3 so that deformable membrane 3 is allowed to assume a generally flat and non-convex configuration as best seen in Fig 3
  • electro-active polymer actuator 20 can be provided so that tab-like elements 5a are normally biased toward deformable membrane 3 in the absence of voltage being applied to the contacts of actuator 20 and are biased in a direction generally parallel with the plane of membrane 3 (generally perpendicular to axis 15) when in a flat configuration as best seen in FIG 3 when a certain voltage is applied to the electrical contacts of electro-active polymer actuator 20
  • deformable lens element 10 includes an axis 15 extending transversely therethrough and that actuator 20 applies a force to a surface of deformable lens element 10 in a direction generally coextensive with axis 15
  • pressure element 4 in the embodiment of Figs 1 -3 will contact deformable lens element 10 at a plurality of contact positions that are spaced apart from and peripherally disposed about axis 15
  • boundary element 1 with first and second planar surfaces 1 10 and 1 1 1 as shown in Figs 2-3 is replaced with a boundary element 1 having an optical power
  • Boundary element 1 of the embodiment of Fig 4 has an un-curved (planar) first surface 1 12 and a convex second surface 1 13
  • Boundary element 1 in the embodiment of Fig 5 has a concave first surface 1 14 and a convex second surface 1 15
  • Figs 1 -3 a first apparatus for moving a deformable lens element 10 by application of a force to an external surface of the lens element is described
  • Alternative apparatuses wherein a force can be applied to a deformable lens element 10 to cause variation in an optical characteristic (e g , lens element surface curvature, focal length) of a deformable lens element are now herein described
  • deformable lens element 10 is provided by a modular assembly described more fully herein, and actuator 20 (shown in the embodiment of Figs 1 -3 as being provided by an ion conductive electro-active polymer actuator) is provided in the embodiment of Fig 6 by a dielectric electro-active polymer actuator 20
  • actuator 20 can comprise a flexible member 21 , a spring 23, a stopper 25 and flexible circuit board 27 for supplying voltage to flexible member 21
  • flexible member 21 can comprise a dielectric film material interposed between flexible electrodes which can be provided e g , by conductive carbon particles suspended in a polymer matrix
  • Spring 23 operates to bias flexible member 21 in a direction toward deformable lens element 10
  • Spring 23 shown as being provided by a conventional coil spring can substituted for by, e g , pressurized fluid or resilient foam
  • stopper 25 operates to hold spring 23 at a certain position relative to flexible member 21 while flex circuit 27 supplies voltage to flexible member 21 having a distal end
  • flexible member 21 expands to push flexible member 21 in the direction of lens element 10 More specifically,
  • focus apparatus 100 can be packaged with use of housing 17 sized and shaped to receive deformable lens element 10 in the modular assembly form shown in the embodiment of Fig 6 and cover 18 which can be adapted to be snap fit onto bolts 19a, 19b, 19c, and 19d
  • Housing 17 can have a plurality of threaded holes aligned with holes of elements 21 , 25, and flex circuit 27 as shown
  • Bolts 19a, 19b, 19c, and 19d can be driven through the aligned through holes and threaded into the shown threaded holes of housing 17 for assembly of apparatus 100
  • Focus apparatus 100 can be adapted so that one or more bolts 19a, 19b, 19c, and 19d conduct electrical current between flex circuit board 27 and flexible member 21
  • flex circuit board 27 and flexible member 21 can be adapted so that bolt 19b connects a voltage terminal of flex circuit board 27 to a first flexible electrode of flexible member 21 and can further be adapted so that bolt 19c completes a conductive
  • actuator 20 in the embodiment of Figs 7-9 is provided by a hollow stepper motor
  • supplying current through one or both of coil 31 or coil 33 causes hollow rotor 35 threadably received on stationary barrel 37 to rotate in such manner that by rotating rotor 35 advances in either direction along axis 15 depending on the signals applied to coils 31 and 33
  • rotor 35 can be shaped so that an end of rotor 35 or a structure element transferring a force generated by rotor 35 contacts a surface of deformable lens element 10 at a plurality of positions peripherally disposed about and spaced apart from axis 15 thereof
  • rotor 35 in the embodiment of Figs 7- 9 is caused to rotate, rotor 35 while contacting deformable lens element 10 at such positions applies a force in a direction generally in the direction of axis 15
  • a hollow stepper motor in one embodiment, generally is characterized by a permanent magnet equipped inner barrel, forming the rotor portion of the motor
  • a hollow stepper motor in one embodiment, can further be characterized by a coil equipped outer barrel, supporting the inner barrel (rotor) Hollow stepper motors exhibit reduced size relative to other types of motors and allow for precision adjustment of lens element positions
  • an inner barrel portion of a hollow stepper motor can include threads that are threadably received in threads of an outer barrel With such a thread arrangement, the motor can sustain high impact relative to gear based motor arrangements
  • threads for receiving an inner barrel in relation to an outer barrel can include threads complementa ⁇ ly configured so that an inner barrel is maintained at a position with respect to outer barrel 37 by way of frictional forces and without application of external energy Accordingly, a lens setting can be controlled to remain at a certain setting simply by avoiding supplying current to a lens driver coil
  • alternative actuator in response to maintain a certain setting simply by avoiding supplying current to a lens driver coil
  • outer barrel 37 can comprise a set of coils 32 corresponding to inner barrel 35
  • a set of coils 32 includes first coil 31 and second coil 33
  • outer barrel 37 includes teeth 41 for engaging teeth 43 of inner barrel 35
  • teeth 41 and teeth 43 provide movement of inner barrel 35 along axis 15 when inner barrel 35 is caused to rotate
  • Inner barrel 35 can have permanent magnets 45 of alternating north and south polarity, which are alternately formed about the circumference of inner barrel 35
  • First coil 31 can have alternating teeth 47, 49 defined by gap 51 When current flows through coil 31 in a forward direction, magnetic fields of opposite polarity are formed at successively adjacent teeth, e g , teeth 47, 49 of coil 31 When current flows through coil 31 in a backward direction, magnetic fields of opposite polarity are again formed at successively adjacent teeth of coil 31 , except the polarity of the magnetic field is the opposite of its polarity during forward direction current flow
  • second coil 33 can have alternating teeth 55, 57 defined by gap 59 When current flows through coil 33 in a forward direction, magnetic fields of opposite polarity are formed at successively adjacent teeth When current flows through coil 33 in a backward direction, magnetic fields of opposite polarity are again formed at successively adjacent teeth of coil 33, except the polarity of the magnetic field is the opposite of
  • actuator 20 as shown in the embodiment of Figs 7-9 can operate substantially in the manner of the embodiment of Figs 1 -3, and of Fig 6 That is, actuator 20 as shown in Figs 7-9 can apply a force generally in the direction of axis 15
  • deformable lens element 10 as shown in Fig 5 can be contacted at a plurality of contact positions defined on an exterior surface of deformable lens element 10 at a plurality of points spaced apart from axis 15 and peripherally disposed about axis 15
  • deformable lens element 10 which can be interchanged into any one of the embodiments of focus apparatus 100 described are described herein in connection with Figs 10- 17
  • deformable lens element 10 comprises first clamping element 63 second clamping element 65 and deformable membrane 3 interposed between first clamping element 63 and second clamping element 65
  • first and second clamping elements 63 and 65 can be transparent (optically clear) and disk shaped as shown and can include respective annularly disposed interlocking teeth
  • clamping element 63 includes three annularly formed tooth rings 64 and clamping element 65 includes a pair of annularly disposed tooth rings 66 as best seen in Figs 1 1 - 12 that engage the teeth of the clamping element 63
  • a plurality of annular rings are provided on each of clamping element 63 and clamping element 65 it is seen that a holding force between clamping element 63 and clamping element 65 would be aided by the presence of a fewer number of tooth rings, e g , only a single annular tooth ring on one of the clamping elements In such manner membrane 3 is clamped between clamping element 63
  • clamping element 65 can be press fit onto clamping element 63 and then can be ultrasonically welded thereto
  • clamping element 63 and clamping element 65 can have complementary tongue and groove engaging surfaces at which an ultrasonic weld can be formed
  • clamping element 63 includes an annular groove 71 (Figs 10- 12)
  • clamping element 65 includes an annular tongue 73 (Figs 10- 12)
  • the location of the tongue and groove can be reversed
  • the ultrasonic weld at the interface between tongue and groove can be supplemented or replaced e g , with an adhesive suitable for use with the material of the clamping elements
  • Planar optically clear window 67 as shown in the embodiment of Fig 1 1 , can be replaced with a curved surfaced member having an optical power
  • An alternative window for use with the deformable lens element as shown in Figs 10- 12 can have, e g , the curved surfaces of element 1 , as
  • clamping element 63 can have a transparent wall 67 allowing light to pass therethrough and can have a sufficient thickness to define a cavity 8 for receiving focus fluid or another deformable substance
  • focus fluid having an index of refraction greater than 1 (where the lens element incorporates a focus fluid) can be input into cavity 8 through hole 75
  • the hole 75 can be sealed
  • clamping element 63 and clamping element 65 each of clamping element 63 and clamping element 65 can be formed of solid non-deformable material
  • clamping element 65 can define an aperture 77 to allow a force supplying element ⁇ e g , pressure element 4 or actuator 20 if pressure element 4 is deleted) to contact membrane 3
  • deformable lens element 10 has a pair of deformable lens surfaces, namely, a first surface defined by first deformable membrane 3 and a second surface defined by second deformable membrane 3'
  • Deformable lens element 10 in the embodiment of Fig 13 is constructed in the manner of the deformable lens element 10 of Figs 10- 12 except that clamping element 63 holding deformable membrane 3 is repeated and clamping element 63 is modified for receipt of second membrane 3' and a second clamping element 65 on an opposite side thereon
  • deformable lens element 10 has teeth as described in connection with the embodiment of Figs 10- 12 for securely holding membranes and annular tongue and groove fasteners formed therein for securely holding a clamping element in relation to clamping element Regarding element Regarding window 67' of center clamping element 63', and where the lens element 10 incorporates a focus fluid, the window 67' can be formed so that a first and
  • Fig 14 shows an embodiment of a focus apparatus 100 incorporating the deformable lens element 10 shown in Fig 13 wherein both of a light entry and light exit surface of the lens element 10 are deformable
  • focus apparatus 100 can have a pair of actuators 20 disposed on either side of deformable lens element 10 including deformable membrane 3 and deformable membrane 3'
  • a first actuator 20 can be disposed as shown to impart a force on an exterior surface of first membrane 3 which may define a light entry surface of deformable lens element 10
  • a second actuator 20 can be disposed as shown to impart a force on an exterior surface of second membrane 3' which may define a light exit surface of lens element 10
  • both of the first and second actuators can have the characteristics described with reference to the embodiment of Figs 1 -3
  • both of the actuators 20 can be disposed so that an aperture 16 of the actuator 20 is disposed about an axis 15 of deformable lens element 10
  • Each of the actuators 20 can be
  • the first and second actuators 20 have apertures 16 disposed about, and in one embodiment, substantially centered on axis 15 of deformable lens element 10 in such manner that a first of the actuators imparts a force in a direction generally coextensive with the axis 15 on a light entry deformable lens surface of the lens element while a second of the actuators 20 imparts a force in a general direction of axis 15 on a light exit surface of the deformable lens element 10
  • the deformable lens element 10 of Fig 13 arranged with appropriate actuators as shown in Fig 14 can be controlled to exhibit a variety of major lens element configurations, e g planar convex, planar concave, bi-convex, bi-concave, concave-convex, meniscus, bi-convex with non-equal surface power
  • the deformable membranes can comprise nonporous optically clear elastomer material
  • a suitable material for use as membrane 3, 3' is SYLGARD 184 Silicon elastomer, of the type available from DOW CORNING
  • cavities 8 can be filled with optically clear focus fluid Selecting a focus fluid with a relatively high index of refraction will reduce the amount of deformation needed to obtain a given change in focal distance
  • a suitable index of refraction would be in the range of from about 1 3 to about 1 7
  • Selecting a focus fluid with a smaller index of refraction is advantageous where it is desired to increase the amount of deformation needed to obtain a given change in focal distance
  • a focus fluid having a lower index of refraction might be selected
  • cavities 8 of the various embodiments can be filled with an alterative deformable optically clear substance having an index of refraction greater than 1 that does not, in the manner of a fluid, assume the shape of its respective cavity 8 when of greater volume than the substance
  • a deformable shape retaining material which can substantially retain its unstressed shape throughout its lifetime can be disposed in cavity 8 in each of the various embodiments of deformable lens element 10
  • a silicon gel can be provided as a resilien y deformable shape retaining material that substantially retains its unstressed shape over the course of its lifetime
  • a resiliently deformable silicon gel can be disposed in cavity 8 of any of the described embodiments
  • liquid silicon can be filled into a container of the desired shape of completed gel member and then cured
  • the liquid silicon can be filled into a mold in the shape of cavity 8 into which the silicon gel member will be disposed, and then cured until in silicon gel form
  • a mold core can be prepared with aluminum by single point diamond turning and nickel plating The cavities can have the negative shape of the resiliency deformable lens element to be made
  • a silicon gel mixture can be prepared such as DOW CORNING JCR61 15 two part silicon Heat Cure gel The two parts, JCR61 15 CLEAR A and J
  • the material forming a resiliently deformable member is provided by an optically clear silicon gel elastomer having an index of refraction greater than 1
  • any optically clear resiliently deformable material having an index of refraction greater than 1 can be utilized in the manufacture of a deformable lens element
  • the formed silicon gel member can be disposed in cavity 8 It will be seen that whereas filling focus fluid and sealing can normally be last steps in a lens element manufacturing method where a lens element incorporates a fluid, disposing a gel member in a cavity can normally be an intermediate step in the manufacture of a gel based deformable lens element [00170]
  • FIG 15 another embodiment of deformable lens element 10 is illustrated The embodiment of Fig 15 has a construction similar to that of the embodiment of Figs 10-12 with resiliently deformable lens member 80 disposed (e g , comprising silicon gel) in a cavity delimited by clamping member 63 and clamping member 65 in place of focus fluid
  • pressure element 4 provided by a push ring is mechanically coupled to clamping member 65 for purposes of aiding the alignment of pressure element 4 with deformable membrane 3
  • deformable lens element 10 incorporates a deformable shape retaining material such as can be provided by silicon gel
  • features of deformable lens element 10 for sealing of cavity 8 can be optionally deleted
  • cavity 8 is deleted and deformable lens element 10 comprises a stacked layer construction including resiliently deformable material member 80, deformable membrane 3, back plate 81 and forward plate 82 adapted to mechanically couple pressure element 4 as shown
  • deformable lens element 10 incorporates a shape retaining resiliently deformable member such as a deformable member comprising silicon gel as described herein
  • deformable membrane 3 can be optionally deleted Nevertheless, with membrane 3, resiliently deformable member 80 may be advantageously protected and the incidence of scratches on the surface of resiliently deformable member 80 can be reduced
  • member 80 may be subject to a coating processing wherein optically clear protective coating 84, such as may comprise SYLGARD 184 from DOW CORNING can be applied to gel member 80 as has been described herein
  • optically clear protective coating 84 such as may comprise SYLGARD 184 from DOW CORNING
  • a process for manufacture of a shape retaining resiliently deformable optically clear member can include filling a container of a desired shape of the finished member and then curing
  • a shape retaining resiliently deformable member, as described herein can be formed to have an initial optical power
  • a shape retaining resiliently deformable member can be formed so that in an unstressed state the deformable member has at least one convex lens surface
  • resiliently deformable member 80 can be formed to have an initial optical power, and is specially configured so that in an unstressed state resiliently deformable member 80 has a first normally (unstressed state) convex surface 85 and a second normally (unstressed state) convex surface 86
  • first normally (unstressed state) convex surface 85 and a second normally (unstressed state) convex surface 86 One of the lens surfaces 85 or 86 can be regarding as a light entry surface and the other a light exit surface
  • first and second electro-active polymer actuators 20 can be disposed to deform each of the first and second normally convex surfaces
  • lens element 10 is shown as being provided as a one piece member consisting of resiliently deformable member 80
  • deformable lens element 10 can be devoid of a focus fluid
  • actuators 20 for deforming deformable lens element 10 can comprise dielectric electro-active polymer flexible members 21 as described previously in connection with the embodiment of Fig 6
  • flexible members 21 are normally biased outward by resiliently deformable member 80 and hence spring 23 is not included in the embodiment of Figs 18 and 19
  • pressure element 4 is deleted in the embodiment of Figs 18 and 19 and the force imparting structural element in the embodiment of Fig 18 and Fig 19 is provided by actuator 20
  • Each flexible member 21 can be disposed to contact deformable lens element 10 provided in the embodiment of Figs 18 and 19 by a one piece resiliently deformable member which in one embodiment comprises a silicon gel
  • each flexible member 21 can be adapted to substantially conform to the unstressed shape of a deformable lens element provided in the embodiment shown by a one piece resiliently deformable member 80
  • each flexible member 21 can include dielectric film
  • Uncoated areas 1 16 in the embodiment of Fig 18 are areas devoid of flexible electrode coating which coating can cover the remainder of the internal and external surfaces of flexible member 21 in areas other than the uncoated areas 1 16
  • dielectric layer 90 can comprise a suitable optically clear material, examples of which include Acrylic, model number VHB4910, available from 3M, and model number CF19-2186 Silicon available from NUSIL
  • an optically clear muscle dielectric material can be spin cured on a carrier substrate (glass plate) to form a uniform thin film The film can then be cured at an elevated temperature After curing, the film can be detached from the substrate and electro-chemically coated to form a flexible electrical coating except in uncoated areas 1 16
  • the formed flexible member can be cut to appropriate size and mounted
  • when voltage is applied to contract a flexible member 21 the resulting force initially generated in a direction generally perpendicular to
  • voltage terminals can be provided in such manner as to appropriately supply voltages across the flexible electrode layers 91 and 92 of the respective first and second flexible members 21 shown
  • Voltage terminals as will be described in an exemplary embodiment can also be provided to structurally support flexible members 21 in a certain position in relation to lens element 10 and the flexible members 21 in turn support resiliently deformable lens element 10
  • imaginary lines connecting terminal connecting interfaces 125 and interfaces 127 (where a first flexible member 21 is connected to conductive rings 94 and 98 and a second flexible member is connected to conductive rings 98 and 96) can bisect deformable lens element 10
  • the flexible member 21 in the embodiment shown can impart a force generally in the direction of axis 15 toward lens element 10 when controlled to move to a contracted state
  • focus apparatus 100 includes bi-convex resilient (shape-retaining) deformable lens element 10 provided by one piece deformable member 80 interposed between a pair of flexible members 21 of first and second actuators 20 adapted to substantially conform to the shape of deformable lens element 10 when in an unstressed state
  • focus apparatus 100 can further include housing elements 93, conductive rings 96 and 94, insulating sleeve 97, and center conductive rings 98
  • Conductive ring 94, center ring 98, and conductive ring 96 are fitted inside insulating sleeve 97, which is disposed to prevent a short between housing element 93 and conductive ring 94 and between housing element 93 and center conductive ring 98
  • conductive sleeve 97 which is disposed to prevent a short between housing element 93 and conductive ring 94 and between housing element 93 and center conductive ring 98
  • conductive ring 97 which is disposed to prevent a short between housing element 93 and conductive
  • the dielectric electro-active polymer actuator as shown in Figs 1 8- 19 can be replaced by an ion conductive electro-active polymer actuator, as described previously herein
  • An ion conductive polymer actuator can have the configuration of the actuator as depicted in Figs 18- 19, except that optically clear dielectric layer 90 can be replaced with one or more optically ion conductive polymer layers
  • the actuator 20 as shown in Figs 18- 19 represents a dielectric electro-active polymer actuator the actuator can generate force (by contraction of the actuator) in a direction generally perpendicular to axis 15, which force is imparted to a deformable surface of lens element 10 in a direction that is generally in the direction of axis 15
  • actuator 20 in the embodiment of Figs 18- 19 represents an ion conductive polymer actuator
  • the actuator can generate a force in a direction generally in the direction of axis 15 (by bending of the ion conductive layer) which force is imparted to a deformable surface of lens element generally in the direction of axis 15
  • the voltage requirements of focus apparatus 100 can be reduced (e g , to less that 10 volts) with selection of an ion conductive electro-active polymer actuator
  • the uncoated area 1 16 can be replaced with an aperture 16 so that the actuator 20 operates in the manner of a force imparting structural element having an aperture 16 as described herein
  • the aperture 16 can be filled with an optically clear material member so that the force imparting structural element operates in the manner of the actuator of Figs 18- 19
  • the actuator in any of the described embodiments can be substituted for by an actuator of any of the remaining embodiments
  • the deformable lens element in any of the described embodiments can be substituted for by a deformable lens element of any of the remaining embodiments
  • Figs 18 and 19 include a deformable bi-convex lens element and an actuator for deforming each of a pair of lens surfaces
  • focus apparatus 100 could alternatively comprise a plano-convex resiliently deformable shape-retaining lens element and a single actuator for deforming the normally convex lens surface
  • a force generated by actuator 20 is transferred to deformable lens element 10 by pressure element 4
  • pressure element 4 can be deleted and that a force generated by actuator 20 can be imparted on deformable lens element 10 directly by actuator 20
  • a structural element namely pressure element 4 or actuator 20 (if the focus apparatus is devoid of pressure element 4)
  • actuator 20 can "contact" a deformable lens element at a plurality of contact positions, or otherwise impart a force to a deformable lens element at a plurality of force impartation points
  • the force-applying structural element can be in separable contact with the deformable lens element, meaning that the force supplying the structural element can be freely separated from the deformable lens element
  • the force- applying structural element can be in secure contact with the deformable lens element, meaning that it is adhered to, welded to, biased toward, or otherwise connected to the deformable lens element
  • the force-applying structural element (e g , the actuator or pressure element) is integrally formed with the deformable lens element, meaning that the force applying structural element is part of a one piece member, a part of which forms the force applying structural element, and a part of which forms at least a part of deformable lens element 10
  • a pulling force generated by actuator 20 ( ⁇ e , in the direction of axis 15 but away from deformable lens element 10) can operate to deform the deformable lens element
  • a pulling force imparted on a surface of a deformable lens element imparted at a plurality of points peripherally disposed about and spaced apart from axis 15 can be expected to decrease a convexity or increase a concavity of the deformable surface where the force applying structural element is ring shaped
  • the force applying structural element can impart a force to a deformable lens element at a plurality of points spaced apart from and peripherally disposed about axis 15 of lens element 10
  • the force applying structural element can impart a force at a plurality of points spaced apart from and peripherally disposed about axi
  • an actuator can impart a force to deformable surface of a deformable lens element generally in the direction of axis 15, however, in the embodiment of Figs 18 and 19, the force impartation points are not formed in a ring pattern that excludes points within a two dimensional area about axis 15
  • force impartation points include points within a two dimensional area about axis 15 of a deformable surface at least part of which transmits image forming light rays
  • the force impartation points can be points of a surface of deformable lens element 10 facing an exterior of deformable lens element 10
  • Force impartation points in various examples are depicted in Figs 20 and 21 , wherein Fig 20 shows an exemplary view of force impartation points being defined in a ring pattern 202 at a plurality of points peripherally disposed about and spaced apart from axis 15, and Fig 21 shows an exemplary depiction of force impartation points defined in an area pattern
  • focus apparatus 100 can be adapted so that an infinitesimal change in the position of actuator 20 provides a significant change in the focus position of an optical imaging system in which apparatus 100 is incorporated
  • Specific performance characteristics that can be realized with use of focus apparatus 100 as described herein are described with reference to the following example [00190] It will be seen from the embodiments of Figs 1 - 19 that the actuator and lens elements can be interchanged in any combination among the embodiments
  • a focus apparatus for use in focusing having a structure substantially according to that shown in Fig 6 is constructed and fitted onto a lens triplet imaging lens assembly of an IT5000 Image Engine of the type available from Hand Held Products, lnc having a focal length of 5 88mm, an F# of 6 6 and a nominal fixed best focus distance of 36 inches
  • Apparatus 100 comprising deformable lens element 10 moveable by way of force applied to an external surface thereof can be incorporated in an optical imaging system (which may alternatively be termed a lens assembly) comprising apparatus 100 and one or more additional lens elements arranged in a series with the apparatus
  • the one or more additional lens elements can comprise deformable or non-deformable lens elements
  • lens assembly 500 (which can also be referred to as an "optical imaging system") for transmission of image forming light rays comprises a single deformable lens element 10 disposed in a focus apparatus 100 according to any one of the embodiments discussed herein
  • the lens element can be provided in a form capable of double convex configuration
  • imaging system 500 for transmission of image forming light rays, comprises a single deformable lens element 10 disposed in a focus apparatus 100 according to any one of the embodiments discussed herein in combination with subassembly 502 More specifically, focus apparatus 100 as shown in Fig 23 is disposed in series with a lens subassembly 502 comprising one or more (as indicated by the dashed in element) rigid non-deformable lens elements 1 1
  • focus apparatus 100 can be an add-on unit detachably received on lens suba
  • FIG 25 a block diagram of an illustrative imaging terminal 1000 incorporating a lens assembly 500 as described herein is shown and described Lens assembly 500 can be incorporated in an imaging terminal 1000
  • Image sensor 1032 can be provided on an integrated circuit having an image sensor pixel array 1033 (image sensor array), column circuitry 1034, row circuitry 1035, a gain block 1036, an analog-to-digital converter (ADC) 1037, and a timing and control block 1038
  • Image sensor array 1033 can be a two dimensional image sensor array having a plurality of light sensitive pixels formed in a plurality of rows and columns Each sensor element of the image sensor array 1033 can convert light into a voltage signal proportional to the brightness
  • the analog voltage signal can then be transmitted to the ADC 1037 which can translate the fluctuations of the voltage signal into a digital form
  • the digital output of the ADC 1037 can be transmitted to a digital signal processor (DSP) 1070 which can convert the image into an uncompressed RGB image file and/or a standard or proprietary image format before sending it to memory
  • DSP digital signal processor
  • Terminal 1000 can further include a processor 1060, an illumination control circuit 1062, a lens assembly control circuit 1064, an imaging lens
  • imaging terminal 1000 can have software and hardware enabling terminal 1000 to operate as a mobile telephone
  • the terminal 1000 can include a microphone 1077 and speaker 1078 in communication with processor 1060 over system bus 1098
  • Terminal 1000 can also have connected to system bus 1098 long range radio transceiver interface 1093 enabling transmittal and receipt of voice packets over a cellular data communication network
  • DSP 1079 can encode an analog audio signal received from microphone 1077 to a digital audio signal to be transmitted to processor 1060 DSP 1079 can also decode an analog audio signal to be transmitted to speaker 1078 from a digital audio signal received from processor 1060 In one embodiment, all the essential functions of the audio signal encoding and decoding can be carried on by DSP 1079 In another embodiment, at least some of the audio encoding/decoding functions can be performed by a software program running on processor 1060
  • Imaging terminal 1000 can also be adapted to operate as a video camera
  • DSP 1070 can be adapted to convert the sequence of video frames captured by the image sensor 1032, into a video stream of a standard or proprietary video stream format (e g , MJPEG, MPEG-4, or RealVideoTM) before transmitting it to volatile memory 1080 or storage memory 1084
  • a standard or proprietary video stream format e g , MJPEG, MPEG-4, or RealVideoTM
  • the recorded video files can be played back via the display 1097 or transmitted to an external computer
  • timing and control circuit 1038 can send image sensor array timing signals to array 1033 such as reset, exposure control, and readout timing signals After an exposure period, a frame of image data can be read out
  • Analog image signals that are read out of array 1033 can be amplified by gain block 1036 converted into digital form by analog-to- digital converter 1037 and sent to a digital signal processor (DSP) which can convert the image into an uncompressed RGB image format or a standard or proprietary image format (e g , JPEG), before sending it to volatile memory 1080
  • DSP digital signal processor
  • the raw image can be sent to the memory 1080 by ADC 1037, and the converting of the image into a standard or proprietary image format can be performed by processor 1060
  • Processor 1060 can address frames of image data retained in RAM 1080 for decoding of decodable indicia represented therein
  • Timeline 1202 shows a state of a trigger signal which may be made active by depression of trigger button 1095
  • Terminal 1000 can also be adapted so that a trigger signal can be made active by the terminal sensing that an object has been moved into a field of view thereof or by receipt of a serial command from an external computer
  • Terminal 1000 can also be adapted so that a trigger signal is made active by a power up of terminal 1000
  • terminal 1000 can be supported on a scan stand and used for presentation reading
  • terminal 1000 can be adapted so that a trigger signal represented by timeline 1202 can be active for the entire time terminal 1000 is powered up
  • Terminal 1000 can be adapted so that trigger signal 1202 can be maintained in an active reading state (indicated by the signal 1202 remaining high) by maintaining trigger button 1095 in a depressed position
  • terminal 1000 can be adapted so that depressing trigger 1095
  • terminal 1000 can be adapted so that after a trigger signal is made active at time 1220, pixels of image sensor 1032 are exposed during first exposure period EXP
  • terminal 1000 may expose, capture, and subject to unsuccessful decode attempts N- I frames of image data prior to successfully decoding a frame of image data corresponding to exposure period EXP N
  • An exposure control signal in one embodiment is represented by timeline 1204 of Fig 26
  • Terminal 1000 can be adapted so that after pixels of image sensor array 1033 are exposed during an exposure period, a readout control pulse is applied to array 1033 to read out analog voltages from image sensor 1032 representative of light incident on each pixel of a set of pixels of array 1033 during the preceding exposure period
  • Timeline 1206 illustrates a timing of readout control pulses applied to image sensor array 1033
  • a readout control pulse can be applied to image sensor array 1033 after each exposure period EXP
  • Readout control pulse 1232 can be applied for reading out a frame of image data exposed during first exposure period EXP
  • Readout control pulse 1234 can be applied for reading out a frame of image data exposed during second exposure period EXP 2
  • readout pulse 1236 can be applied for reading out a frame of image data exposed during third exposure period
  • EXP 3 A readout control pulse 1238 can be applied for reading out a frame of image data exposed during exposure period EX
  • terminal 1000 can be adapted so that terminal 1000 can formatize frames of image data
  • terminal 1000 can be adapted so that processor 1060 formats a selected frame of image data in a compressed image file format, e g , JPEG
  • terminal 1000 can also be adapted so that terminal 1000 formats frames of image data into a video stream format (e g , MJPEG, MPEG-4, or RealVideoTM) for transmitting to an external computer or for recording of digital movies
  • Terminal 1000 can also be adapted so that processor 1060 can subject to a decode attempt a frame of image data retained in memory 1080
  • processor 1060 can execute the following processes First, processor 1060 can launch a scan line in a frame of image data, e g , at a center of a frame, or a coordinate location determined to include a decodable indicia representation Next, processor 1060 can perform a second derivative edge detection to detect edges After completing edge detection, processor 1060 can determine data indicating widths between edges Processor 1060 can then search for start/stop character element sequences, and if found, derive element sequence characters character by character by comparing with a character set table For certain symbologies, processor 1060 can also perform a checksum computation If processor 1060 successfully determines all characters between a start/stop character sequence and successfully calculates a checksum (if applicable), processor 1060 can output a decoded message When outputting
  • Times at which terminal 1000, in one embodiment, attempts to decode a decodable indicia represented in a frame of image data are illustrated by periods 4332, 4334, 4336, 4338, and 4340 of timeline 1208 as shown in the timing diagram of Fig 26 Regarding timeline 1208, period 4332 illustrates a period at which terminal 1000 attempts to decode a first frame of image data having associated exposure period EXP
  • Terminal 1000 can be adapted so that lens assembly 500 has a plurality of lens settings It has been described that the various lens settings of lens assembly 500 can be realized by applying a force to one or more deformable lens elements
  • terminal 1000 can have 7 lens settings At each lens setting, lens assembly 500 and therefore terminal 1000 can have a different plane of optical focus (best focus distance) and a different field of view, typically expressed by the parameter "half FOV" angle
  • Each different lens setting can have a different associated focal length half FOV angle, and plane of nominal focus
  • terminal 1000 can be adapted to "cycle" between various lens settings according to a predetermined pattern, while a trigger signal remains active
  • terminal 1000 can be adapted while a
  • terminal 1000 can determine whether a first frame, / e , the frame having the exposure period EXPi is in-focus
  • a determination of whether a frame is in-focus can include an examination of the "flatness" of a frame of image data Plotting pixel values of a frame in a histogram, an out-of focus frame will have a relatively "flat" distribution of pixel value intensities with a relatively even distribution of intensities over a range of intensities
  • An in-focus frame on the other hand can be expected to have, relative to an out-of-focus frame, substantial incidences of pixel values at certain intensities and substantially fewer incidences at other intensities
  • terminal 1000 at block 1502 determines that present frame is in-focus terminal 1000 can proceed to block 1512 to maintain the lens setting at the setting determined to be in-focus and can subject the frame to processing
  • the processing can include, e g , subjecting the frame to an indicia de
  • terminal 1000 at block 1506 can examine a frame having a different focus setting than the frame of image data examined at block 1502
  • a frame having a "certain lens setting” it is meant that the focus setting of lens assembly 500 was set to the certain setting during the exposure period associated to the frame
  • terminal 1000 at block 1504 determines that the frame examined at block 1504 is in-focus
  • terminal 1000 can proceed to block 1512 to maintain the lens assembly 500 at the current setting (the setting yielding to the frame determined to be in-focus) and process a frame or frames exposed with the lens assembly 500 at the determined in-focus setting
  • the frame examined at block 1506 can proceed to block 1510 to determine an in-focus setting based on a processing of the first frame examined at block 1502 and the second frame examined at block 1504
  • Such processing can include evaluating the impact on the flatness of a frame by changing a lens setting (e g , an algorithm may run so that if captured frame becomes more flat [less in-focus] by moving the lens setting from a first setting to a second setting having a farther best focus distance than the first setting, the lens setting is set to a certain setting having a shorter best focus distance than the first setting responsively to the processing)
  • terminal 1000 sets the lens assembly 500 to the determined in-focus setting and can advance to block 1512 to process a frame(s) having exposure periods coinciding with times at which the lens setting is set to the determined in-focus setting If the frame examined at block 1506 is determined at block 1508 to be in
  • a mobile hand held housing 1091 for incorporating and supporting the components of Fig 25 is shown and described
  • the generic form factor of Fig 28 represents the common form factor of a mobile e g , cellular telephone or a portable data collection terminal for use in data collection applications
  • Terminal 1000 can also incorporate a housing in other familiar form factors e g , a digital camera or a camcorder form factor
  • terminal 1000 can have a plurality of operator-selectable configurations Each configuration can have a different associated lens setting control algorithm That is, the method by which terminal 1000 controls a lens setting of lens assembly 500 responsively to a trigger signal being made active changes depending on which configuration is selected
  • configuration 1 terminal 1000 cycles between various lens settings according to a predetermined pattern Specifically in configuration 1 , terminal 1000 changes a lens setting to a next lens setting after each exposure period, and then decrements the lens setting by 1 after a frame has been captured using the maximum far focus setting (L7)
  • configuration 2 terminal 1000 responsively to a trigger signal 1202 being made active changes lens settings of terminal 1000 according to an adaptive pattern
  • the row entries of configuration 2 illustrate a lens setting change pattern that might be exhibited by terminal 1000 when executing an auto-focus algorithm
  • frame 1 and frame 2 having associated exposure periods 1 and 2
  • frame 4 corresponding to EXP 4 might have a lens setting of L2 if the processing of frames 1 and 2 indicates that setting L2 is an in-focus setting
  • configuration 3 terminal 1000 does not change the lens setting but rather maintains the lens setting of terminal 1000 at a fixed short focus position
  • a focus module containing a boundary element and a focus element The focus element includes a fluid and a deformable membrane, with the fluid being entrapped between the boundary element and the deformable membrane
  • the focus module also includes
  • a pressure element which is capable of deforming the focus element by pressing on the deformable membrane in the direction of the boundary element
  • the present invention provides a focus module for use in a fluid lens that in particular has few moving parts and does not require the presence of multiple chambers or reservoirs for the fluid component of the lens
  • the present invention is directed to a focus module which may include the following elements
  • boundary element which may be rigid (such as glass or plastic) or deformable (such as elastomer),
  • a spacer element interposed between the boundary element and focus element, 3) a focus element, deformable in at least one dimension (such as a fluid or elastomer),
  • a deforming or actuator element such as artificial muscle or electrically actuated polymer to act upon the focus element
  • a housing element to provide a physical housing or anchor for the assembly
  • a power source generally located external to the focus module, for powering the conductor element
  • the deforming element may also function as the spacer element, the spacer element may be omitted, as when the lens is provided by use of a unitary fluid-filled element as discussed hereinbelow, the pressure element may be omitted, with the deforming element acting directly on the focus element, and the housing element is essentially a container into which the other elements may be placed, or in which they may be assembled, and whose function may be provided by other structural elements in the apparatus or device in which the focus module is to function
  • the boundary element may be rigid, such as glass or plastic, or deformable, such as an elastomer
  • the elasticity of the boundary element is such that the boundary element will not deform in response to the force or energy that will be communicated to it when the focus element is at maximum deformation
  • the focus module includes a boundary element, spacer element, and focus element, with the focus element comprising a fluid and a deformable membrane where the fluid is entrapped between the boundary element and the membrane, and, a pressure element is used to deform the focus element by exerting pressure on the fluid, whether by pressing on the membrane in the direction of the boundary element or by decreasing the diameter of the fluid space between the boundary element and the membrane (for example, by annular tightening), if it is desired that the boundary element not deform, then it should be sufficiently rigid to remain planar when the pressure element is exerting maximum pressure on the fluid
  • glass may be used, and a variety of optical glass materials are commercially available, including, for example, Corning® EAGLE2000TM Display Grade glass, available from Corning Display Technologies, Corning, New York USA, and N-BK.7 glass, available from Schott North America lnc , Duryea, Pennsylvania USA
  • the boundary element may be any suitable thickness, including from about 0 I mm to about I mm, for example, 0 2, 0 3, or 0 4 mm
  • the spacer element may be any of a variety of materials, including metal, plastic, and ceramic, depending on its desired functionality When that functionality is limited to spacing the boundary element from the focus element it may be any material that is compatible with the other materials it will contact, including the focus fluid, such as stainless steel When it is also desired to provide a seal between itself and the boundary element and/or the focus element, the spacer may be a two-sided tape When it is desired to serve as the deforming or actuator element it may be an artificial muscle or electro-actuated polymer as discussed
  • a gap or port may be present in the spacer element, shown in Fig 29 as element 2a After the fluid chamber has been filled with focus fluid, this gap or port may be sealed by any means that will both prevent fluid from escaping the chamber, and will withstand the pressure subsequently exerted by the focus fluid as in response to actuation of the deforming element
  • an epoxy adhesive may be used to provide this seal
  • the focus element may be a single component, such as a fluid-filled-filled elastomer, polymer, or plastic, for example, a transparent oil-filled elastomer material which has an elastic memory
  • the focus element may be two or more components, with a focus fluid (such as water or oil) entrapped or sandwiched between the boundary element and a deformable focus membrane, in which configuration the focus fluid and the focus membrane would together comprise the focus element
  • suitable materials would include polydimethylsiloxane, or PDMS, such as Sylgard® 184 silicone elastomer, available as a kit from Dow Corning Corporation, Midland, Michigan, USA
  • the membrane thickness may be selected based on factors such as the size of the focus module in question and may be, for example, from about 0 1 to about 1 mm, for example, 0 2, 0 3, or 0 4 mm
  • Optical fluids and optical grade oils such as optical grade mineral oils
  • One suitable optical fluid is Type A immersion oil, available from Cargille-Sacher Laboratories Inc , Cedar Grove, New Jersey, USA
  • Another suitable fluid is the Santovac® polyphenyl ether-based optical fluid SL-5267, available from Arch Technology Holding LLC , St, Charles, Missouri, USA Water may also be used, such as de-ionized water
  • the boundary element and focus element must be optically clear, at least in that portion thereof used to transmit image information
  • the entirety of each such element would normally be optically clear in order to simplify manufacture and assembly, it is also possible for at least a part of an outer ring portion of either or both of the boundary element and focus element to be translucent or opaque, surrounding an inner portion that is optically clear
  • the materials selected for the boundary element and focus element should have similar indices of refraction
  • the focus module includes a glass boundary element, a focus fluid, and a focus membrane
  • the closer the indices the less light will be lost to reflection
  • the indices will ideally identical, and preferably will be within about +/- 0 001 to 0 01 , such as about 0 002
  • differences in the indices of refraction may be advantageous, such as to reduce certain types of aberrations
  • a suitable index of refraction would be in the range of from about 1 3 or about 1 5 to about 1 6 or about 1 7, such as an index of about 1 5 or about 1 6
  • the pressure element may similarly be any of a variety of materials, including metal, plastic, and ceramic
  • the choice of material will depend on compatibility with other materials and on the desired response to force exerted by the deforming element If it is desired that the pressure element not itself deform, it should be an inelastic material such as metal, ceramic, or plastic If, however, it is desired or necessary that the pressure element change its shape or configuration in response to the deforming element, it should be composed of a deformable material such as an elastomer
  • the deforming element is the component that responds to a control signal by varying the force applied to the focus element, either indirectly (such as through the pressure element) or directly Particularly suitable for use as the deforming element are electroactive or electroconducting polymer actuators
  • electroactive or electroconducting polymer actuators One example is Electroactive Polymer Artificial Muscle and/or the Universal Muscle ActuatorTM platform, available through Artificial Muscle, lnc , of Menlo Park, California, USA
  • Another example is conducting polymer actuator available from EA MEX Corporation of Osaka, Japan
  • the deforming element is an artificial muscle or electro-actuated polymer
  • the deforming element may be provided as two or more layers, analogous to layers of muscle fiber
  • this effect may be used to select a given direction of motion for the overall layered assembly
  • the rectangular solid may then curl up as shown in Fig 45, extend laterally as shown in Fig 46, or curl down as shown in Fig 47, or even twist, in response to electrical stimuli, though use of a non-elastic structure to constrain one or more directions of motion, or to force the motion in a particular manner, may be required
  • Figs 45 and 47 depict non-uniform curvature of the rectangular solid, which could be accomplished by constraining a portion of the rectangular solid such as by a frame or other external structure (not shown), by anchoring or
  • Figs 48 and 49 demonstrate a bi-convex electro-actuated polymer membrane lens
  • both surfaces are deformable membranes
  • the two surfaces of the membranes may have different surface curvatures due to different membrane diameters
  • Differences in the material, and thickness, of the membrane can also be used to create different surface shapes
  • Fig 50 shows a multiple deformable membrane lens assembly, and it should be noted that a zoom lens can be achieved using two (or more) lenses actuated by electro-actuated polymer and other fixed elements
  • Figs 51 and 52 show that by placing a conventional lens in an electro-actuated polymer mechanism, a variable location lens element can be made for compact auto-focus or zoom applications, with additional fixed elements
  • the deforming element may act directly on the focus element, as by being in direct contact with it Alternatively, force generated by activation of the deforming element may be transmitted to the focus element through one or more intermediary devices or elements
  • a pressure element may be ad j acent to and in contact with the focus element, and the deforming element may press on the pressure element, which transmits that force through to the focus element
  • the pressure element may be in the shape of an annulus, or doughnut, and may be in direct or indirect contact with an outer ring portion of the focus element
  • the conductor element communicates the control signal to the deforming element
  • the deforming element responds to electric signals, as in the case of electro-actuated polymers, it generally serves as a conductor for conducting electrical motive power from the power source to the deforming element
  • Specific examples include use of flexible printed circuits (FPC) and sputtering or evaporating a conductive metal onto the surface of the deforming element
  • the conductor element comprises two components, one on either side of the deforming element, with each component having an electrical contact access 6c for connection to a power source
  • the deforming element will be uniformly activated or deactivated in response to the presence or absence of an electrical signal, and the convex meniscus formed by the focus element will be symmetrical
  • the conductor element may include a plurality of circuits enabling selective actuation of one or more portions of the deforming element, thereby allowing tunable steering of the focus element by enabling the convex meniscus to be selectively asymmetric
  • the deforming element is shown as a single conductive element
  • the deforming element could be constructed, such as by the use of insulating materials between flex circuits, such that each finger (also shown as elements 5a in Fig 30), or combinations thereof, provide separate and independently energizable circuits
  • tilt refers to the possible combinations of pitch and yaw that may be used to configure the meniscus to have shapes other than symmetric to an axis normal to the boundary element and centered in the fluid chamber
  • focus fluid 3b has been further represented as having meniscus element 3c, shown as having a non-symmetric shape in response to selective application of control signals to a multi-circuit conductor element (not shown)
  • the conductor element is connected to a power source selected to deliver the range and polarity of voltage necessary to drive the deforming element through its full intended range of motion
  • Fig 29 provides an exploded view of one embodiment of the focus module
  • spacer element 2 creates a spaced-apart relationship between boundary element I and focus element 3
  • Pressure element 4 rests against focus element 3, and is acted on by deforming element 5, which is itself acted on by conductor element 6
  • conductor element 6 comprises two sub- elements 6a and 6b, which are conductive elements used to transmit electrical control signals to deforming element 5
  • Element 6c is an electric contact access for conductor element 6
  • a complementary electric contact access is present on element 6a, but is not visible in Fig 29
  • Element 7 is a housing element, and serves to provide a physical environment for the focus module
  • Figs 30 and 31 show the focus module embodiment of Fig 29 in assembled form, in which housing element 7, electrical contact element 6c, deforming element 5, and pressure element 4 are most visible
  • housing element 7, electrical contact element 6c, deforming element 5, and pressure element 4 are most visible
  • the assembled focus module is viewed from the right side of Fig 29, with the boundary element closest to the viewer
  • Fig 31 the assembled focus module is viewed from the left side of Fig 29
  • the overall size of the assembled focus module is not critical and may be varied depending on the size of the available components, the device into which it will be placed or assembled, and the needs of the user
  • the focus module which is generally cylindrical as shown in Figs 30 and 31 , will have a diameter d of from about 5, 7, or 9 mm to as large as about 1 1 , 13, 15, or 20 mm
  • the size may be selected in order to maximize or achieve drop-in compatibility with existing devices, for example, in camera-enabled cellular telephones, a diameter of about 9, 9 5, or 10 mm may be preferred
  • Figs 32 and 34 each depict an assembly including a boundary element 1 , focus fluid 3b, focus membrane 3a, and deforming element 5
  • minimal pressure is being applied to focus fluid 3b
  • focus membrane 3a is correspondingly planar
  • pressure is being applied by deforming element 5 to focus fluid 3b, and as a result focus membrane is forming a convex lens or meniscus
  • the pressure applied by deforming element 5 is exerted in a direction substantially normal to the plane represented by focus membrane 3a and in the direction of boundary element 1 , reducing the height of the chamber containing the focus fluid around its circumference and thereby forcing fluid from the periphery of the fluid chamber into the middle, this effect produces the convex meniscus visible in Fig 33
  • the deforming element may act on the focus element directly or indirectly Also as previously indicated, direct action may involve placing the deforming element directly adjacent the focus element, for example, directly contacting the focus membrane when the focus element is comprised of a focus membrane and a focus fluid entrapped between the focus membrane and the boundary element, with a spacer element defining the wall of a chamber holding the focus fluid
  • the deforming element may itself comprise the wall separating the boundary element and the focus membrane This embodiment is shown in Fig 34, where deforming element 5 is also serving as the wall of the cylindrical chamber containing the focus fluid 3b, that chamber having a 'top' wall formed by the focus membrane 3a and a 'bottom' wall formed by the boundary element 1
  • the pressure exerted by deforming/spacer element 5 is exerted in a direction substantially parallel to the plane represented by focus membrane 3a and in the direction of the middle of the fluid chamber Depending on the characteristics of the material used for the deforming element, this pressure may not be accompanied by any change in height of the fluid chamber, and the deforming element may simply increase its thickness radially Alternatively, the extension of the deforming element radially inward may be accompanied by a decrease in height or thickness of the deforming element inward as shown in Fig 35, effectively drawing focus membrane 3a and boundary element 1 towards each other and contributing to the formation of the convex meniscus, not only is the inward radial movement of the deforming element forcing the focus fluid to occupy a smaller-diameter cylinder, but the drawing-together of the focus membrane and boundary element are also reducing the height of that cylinder
  • the focus module may include a cylinder 4100 having at least a top surface 4101 , a bottom surface 4102, an outer wall 4103, a fluid interior volume 4104, the cylinder having diameter d and height h
  • the actuator element When the actuator element is external to this structure it will exert pressure on at least one of the top surface, bottom surface, or outer wall in order to reduce one or both of height h and diameter d
  • this reduction in height and/or diameter must be offset by a corresponding expansion of the volume in some direction which, in the case of the focus module, will involve deformation of one or both of top surface 4101 and bottom surface 4102
  • Figs 39 and 40 provide a simplified, straight side-on view of this effect
  • Fig 39 provides an illustration of deformation caused by a reduction in height, with the cylinder now having the same diameter d but height h' ⁇ h
  • Fig 40 provides an illustration of a deformation caused by a reduction in
  • the deforming or actuator element may comprise part or all of outer wall 4103, as show in Figs 41 and 42
  • the cylinder is shown in cross-section to illustrate the annular nature of deforming element 5
  • the upper deformable surface (not shown) will be planar
  • the deforming element has responded to actuation by contracting in the vertical or "h" dimension and extending or elongating in the horizontal or "d” dimension
  • Fig 42 the effect is shown with the deforming element drawing the upper and lower surfaces together uniformly over their entire surface area, which requires that the exterior circumference of one or both be vertically moveable or slideable rather than fixed or anchored
  • directional references such as "horizontal,” “vertical,” and the like are generally used in the relative rather than absolute sense, with, for example, vertical referring to the direction defined by a line normal to the top and bottom surfaces when both are planar, and horizontal referring to the direction defined by a line parallel to those surfaces when both are planar
  • it is generally used in the relative rather than absolute sense with, for example,
  • the pressure ring and deforming element could be positioned under the focus membrane, between that membrane and the spacer element, and activation of the deforming element could increase, rather than decrease, the height of the fluid chamber around its circumference or periphery
  • the deforming element also served as the spacer element, as discussed elsewhere herein, with the pressure element positioned between the deforming element and the focus membrane
  • the pressure element need not be present, in which case the deforming element would act directly on the focus membrane
  • Another concave lens embodiment may be considered in reference to a particular method of preparing and filling the fluid chamber First, one or more boundary elements, such as glass plates, are placed in recesses provided in a support structure such as a metal plate Spacer elements, such as double-sided tape, are then placed on each glass plate Next, a sheet or layer of PDMS is placed over the glass plate-spacer element assemblies, this sheet may, for example, be prepared by spin-coating the PDMS to a desired thickness using known techniques The resulting assemblies of glass plate boundary element, spacer element, and PDMS membrane element are then placed under vacuum, focus fluid is added, and the vacuum is released to draw the focus fluid into the fluid chambers If this filling process is stopped before the fluid chambers are completely filled, the initial shape of the focus membrane will be concave Depending on the degree of concavity selected, and the parameters chosen for the rest of the focus module, the resulting module may function only by varying the degree of concavity of the focus element, or may be capable of deforming the
  • the deforming element has an active and passive state, depending on whether or not a control signal is being applied, and has a continuous transition between the two states, preferably in linear response to the strength of the control signal
  • the system may be configured either such that the deactivated state is when maximum force is being applied to the focus element, or when minimal force is being applied
  • Figs 32 and 34 may be characterized as representing deactivated states, the system being configured such that the deforming element is communicating minimum force to the focus fluid when no control signal is being applied, and Figs 33 and 35 may represent activated states, in which a control signal is being applied to energize the deforming element
  • Figs 32 and 34 represent that state of the system when the control signal is being applied
  • Figs 33 and 35 represent its state when the control signal is at zero or minimal strength
  • the deforming element may either be relaxed (as in Figs 32 and 34) when the power is off and stretched or expanded (as in Figs 33 and 35) when power is on, or vice versa This generally translates into what the desired 'resting' state of the focus module should be
  • the focus membrane is planar the focus is set to infinity, and when it is convex the focus is at a finite distance, such as from about 5 mm to about 500 mm, including all
  • the deforming element and related assembly of the present invention may also be used to control motion of a conventional, rather than fluid, lens It is further possible to combine the focus module of the present invention with one or more conventional or fluid/adaptive lenses, and/or with one or more other focus modules In this way further functionalities such as zoom or auto zoom may be realized.
  • the focus module may be used in a wide variety of devices having or using imaging capabilities, including data collection devices such as bar code scanners, portable data terminals (PDTs), portable data assistants (PDAs), camera-enabled cellular telephones, still picture cameras, moving picture cameras, and the like, further including both fixed-mount and portable devices
  • data collection devices such as bar code scanners, portable data terminals (PDTs), portable data assistants (PDAs), camera-enabled cellular telephones, still picture cameras, moving picture cameras, and the like, further including both fixed-mount and portable devices
  • the focus module may be used in any size and type of such device, but due to its small size and minimal use of moving parts, it is especially well-suited for devices where minimal use of space is particularly desirable, and/or where ruggedization is desired against shock, vibration, and other environmental influences that could affect the operability and/or effective lifespan of components having more and/or more delicate moving parts
  • the present invention may be applied to apparatus and methods useful for imaging, capturing, decoding and utilizing information represented by encoded indicia such as bar codes (for example, 1 D bar codes, 2D bar codes, and stacked bar codes), optically recognizable characters (for example printed, typed, or handwritten alphanumeric symbols, punctuation, and other OCR symbols having a predefined meaning), as well as selected graphical images such as icons, logos, and pictographs
  • the apparatus and methods involve the use of one or more focus modules with data readers such as hand held bar code readers to accomplish such tasks as imaging barcodes and other optically readable information, including focusing on images of interest, and improving image quality by removing artifacts such as jitter introduced by a user who is manually operating a reader of the invention
  • the device which bas been described and which has been termed a liquid lens of variable focal length has many other applications It may be employed, for example, as an electrostatic voltmeter, as the alteration in the divergence or convergence of a translated beam is a function of the intensity of the impressed field
  • the device may be employed in connection with suitable apparatus for the transmission of audible or other signals over a beam of light
  • the device When the device is employed in connection with transmission of audible signs it may be said to modulate the beam of light at audible frequencies, and where such an expression is used in the claims it should be so interpreted It is also suited for use in sound-recording on motion picture film
  • the focus module of the present invention is generally driven by what may be characterised as an electric potential
  • the electrical signals or stimuli used to control the focus module may be characterized in terms of voltages (electric potentials, or electric potential differences), as well as other electrical parameters, such as electric current or electric charge (the time integral of electric current)
  • the focus module, and in particular the deforming element (as acted upon through the conductor element) may be controlled by an applied electrical signal for driving any type of fluid (or reconfigurable) lens that responds to the applied signal by exhibiting adjustable behavior based on the interaction of light with two or more fluids (or a fluid and vacuum) having differing optical indices
  • the readers of the invention can in some embodiments be hand held, portable apparatus that can image encoded indicia, such as bar codes of a variety of types ( I D, 2D, stacked I D, and other bar codes), and symbols such as handwritten, printed, and typed characters (for example using optical character recognition methods), as well as imaging surfaces or objects that are amenable to being identified using optical illumination
  • Fig 53 is a diagram showing a reader 900, such as a bar code scanner, embodying features of the invention
  • the reader 900 comprises various optical components and components of hardware and software for controlling the operation of the reader 900 and for analyzing an image acquired by the reader 900
  • Fig 54 is a diagram showing the control circuitry of the reader of Fig 53 in greater detail
  • a case 902 is shown in dotted schematic outline
  • the case 902 can in principle be any convenient enclosure or frame for supporting the various components in suitable mutual orientation, and in some embodiments is a case adapted to be held in a hand of a user, as described in greater detail hereinbelow in conjunction with Figs 51 and 52
  • the reader 900 comprises sources of illumination 904, 906 that can be operated in various circumstances to illuminate a target and to provide an aiming signal
  • the illumination source 904 is in general a source comprising one or more light sources such as lamps or LEDs that provide illumination at a convenient wavelength, such as red or green illumination, for illuminating a target whose
  • the reader 900 also includes various hardware components, shown in a single control element 930 for controlling and for acquiring signals from the reader 900 in Fig 53 The details of control element 930 are shown in Fig 54
  • An illumination control 931 is provided to control the intensity and timing of illumination provided by the illumination source 904
  • the illumination control 931 is in electrical communication with illumination source 904 by way of a cable 905 comprising conductors
  • An aimer control 932 is provided to control the intensity, color and timing of illumination provided by the aimer source 906
  • the aimer control 932 is in electrical communication with aimer source 906 by way of a cable 907 comprising conductors
  • An imager control 934 is provided to control the timing and operation of the imager 922, for example by providing clocking signals to operate the image, reset signals, start and stop signals for capturing illumination, and synchronization signals for providing electrical output as data indicative of the intensity of illumination received at any pixel of the imager array 922, which data may be provided as analog or as digital data
  • An analog-to-digital converter 936 is provided for converting analog signals output by the imager 922 to digital signals
  • a DMA controller 948 is provided to allow direct transfer of digital data to a memory for storage
  • any and all of illumination control 931 , aimer control 932, imager control 934, A/D 936 and DMA 948 are connected to a general purpose programmable computer 942 by way of one or more buses 945, which buses 945 may be serial buses or parallel buses as is considered most convenient and advantageous
  • the general purpose programmable computer 942 comprises the usual components, including a CPU 943 which can in some embodiments be a microprocessor, and memory 944 (for example semiconductor memory such as RAM, ROM, magnetic memory such as disks, or optical memory such as CD-ROM)
  • the general purpose computer can also communicate via one or more buses 947 with a wide variety of input and output devices
  • an output device 946 such as a display, a speaker 948 or other en
  • a laser bar code scanner can be implemented with a steering lens configuration See Figs 86-88 hereinbelow Rather than using a scanning mirror or motor as presently used in bar code scanners, the scanning motion can be achieved with a steerable fluid lens At the same time the laser spot location of narrowest beam width can also be effected with the same or a different fluid lens
  • Such a scanning system can also be coaxial in nature, where the receive and transmit light beams both focus at the same section of the bar code pattern being scanned This receive optical system is not shown, but these are well known to those in the art
  • a cylindrical or spherical scanning fluid lens may be used depending upon if the designer wishes to develop a single scan line or a raster scan line It is also envisioned that it may be possible to develop a fluid element that scans only, without having optical power Such systems are also contemplated
  • the distance at which the reader of the invention can operate, or equivalently, a focal length of the optical system of the reader can vary as the distance q from the lens to the object to be imaged vanes
  • the focal length for a specific geometrical situation can be determined from the formula
  • f is the focal length of a lens
  • p is the distance from the lens to a surface at which a desired image is observed (such as an imaging sensor or a photographic film)
  • q is a distance between the lens and the object being observed
  • the lens can be caused to either manually or automatically change its focal length until the best focus is achieved for an object at a given distance away
  • One way to do this is to minimize the so-called blur circle made by a point or object within the field of view
  • This can be done automatically by a microprocessor that vanes the focal length of the lens and measures the size of the blur circle on a CCD or CMOS imager, i e the number of pixels the blur circle fills
  • the focal length at which the blur circle is smallest is the best focus and the lens is held at that position If something in the field of view changes, e g the object gets farther away from the lens, then the microprocessor would detect the change and size of the blur circle and reinitiate the automatic focusing procedure
  • the object used to measure the blur circle could be a detail inherently in the field of view, or it could be a superimposed object in the field of view
  • an IR laser spot into the field (the wavelength of the IR is beyond the sensitivity of the human eye, but not of the CCD or CMOS image sensor)
  • Another means of achieving best focus includes transforming the image into the frequency domain, for example with a Fourier transform, and then adjusting the focal length of the fluid lens to maximize the resulting high frequency components of that transformed image Wavelet transforms of the image can be used in a similar fashion
  • Both the frequency domain and wavelet techniques are simply techniques for achieving best focus via maximization of contrast among the pixels of the CCD or CMOS image sensor
  • Fig 55 is a block diagram of an optical reader showing a general purpose microprocessor system that is useful with various embodiments of the invention
  • Optical reader 4010 includes an illumination assembly 4020 for illuminating a target object T, such as a 1 D or 2D bar code symbol, and an imaging assembly 4030 for receiving an image of object T and generating an electrical output signal indicative of the data optically encoded therein
  • Illumination assembly 4020 may, for example, include an illumination source assembly 4022, together with an illuminating optics assembly 4024, such as one or more lenses, diffusers, wedges, reflectors or a combination of such elements, for directing light from light source 4022 in the direction of a target object T
  • Illumination assembly 4020 may comprise, for example, laser or light emitting diodes (LEDs) such as white LEDs or red LEDs
  • Illumination assembly 4020 may include target illumination and optics for projecting an aiming pattern 4027 on target T Illumination assembly 4020 may be eliminated if ambient light levels are certain
  • the array-based imaging assembly shown in Fig 55 may be replaced by a laser array based scanning assembly comprising at least one laser source, a scanning mechanism, emit and receive optics, at least one photodetector and accompanying signal processing circuitry See Figs 86, 87, and 88 hereinbelow, and the associated description
  • a partial frame clock out mode is readily implemented utilizing an image sensor which can be commanded by a control module to clock out partial frames of image data or which is configured with pixels that can be individually addressed Using CMOS fabrication techniques, image sensors are readily made so that electrical signals corresponding to certain pixels of a sensor can be selectively clocked out without clocking out electrical signals corresponding to remaining pixels of the sensor, thereby allowing analysis of only a partial frame of data associated with only a portion of the full imager field of view CMOS image sensors are available from such manufacturers as Symagery, Omni Vision, Sharp, Micron, STMicroelectronics, Kodak, Toshiba, and Mitsubishi
  • a partial frame clock out mode can also be carried out by selectively activating a frame discharge signal during the course of clocking out a frame of image data from a CCD image sensor A/D 1036 and signal processor 1035 may individually or both optionally be integrated with the image sensor 1032 onto a single substrate
  • Optical reader 4010 of Fig 55 also includes programmable control circuit (or control module) 1040 which preferably comprises an integrated circuit microprocessor 4042 and an application specific integrated circuit (ASIC 4044)
  • ASIC 4044 could also be provided by a field programmable gate array (FPGA)
  • FPGA field programmable gate array
  • Processor 4042 and ASIC 4044 are both programmable control devices which are able to receive, to output and to process data in accordance with a stored program stored in memory unit 4045 which may comprise such memory elements as a read/write random access memory or RAM 4046 and an erasable read only memory or EROM 4047
  • Other memory units that can be used include EPROMs and EEPROMs RAM 4046 typically includes at least one volatile memory device but may include one or more long term non-volatile memory devices
  • Processor 4042 and ASIC 4044 are also both connected to a common bus 4048 through which program data and working data, including address data, may be received and transmitted in either direction to any circuitry that is also connected there
  • processor 4042 is preferably a general purpose, off-the-shelf VLSI integrated circuit microprocessor which has overall control of the circuitry of Fig 55, but which devotes most of its time to decoding image data stored in RAM 4046 in accordance with program data stored in EROM 1047 ASIC 4044, on the other hand, is preferably a special purpose VLSI integrated circuit, such as a programmable logic array or gate array that is programmed to devote its time to functions other than decoding image data, and thereby relieves processor 4042 from the burden of performing these functions
  • processors 4042 and 4044 will naturally depend on the type of off-the-shelf microprocessors that are available, the type of image sensor which is used, the rate at which image data is output by imaging assembly 4030, etc There is nothing in principle, however, that requires that any particular division of labor be made between processors 4042 and 4044, or even that such a division be made at all This is because special purpose processor 4044 may be eliminated entirely if general purpose processor 4042 is fast enough and powerful enough to perform all of the functions contemplated by the present invention It will, therefore, be understood that neither the number of processors used, nor the division of labor there between, is of any fundamental significance for purposes of the present invention
  • processors 4042 and 4044 are preferably devoted primarily to such tasks as decoding image data, once such data has been stored in RAM 4046, recognizing characters represented in stored image data according to an optical character recognition (OCR) scheme, handling menuing options and reprogramming functions, processing commands and data received from control/data input unit 1039 which may comprise such elements as a trigger 1074 and a keyboard 1078 and providing overall system level coordination
  • OCR optical character recognition
  • Processor 4044 is preferably devoted primarily to controlling the image acquisition process, the A/D conversion process and the storage of image data, including the ability to access memories 4046 and 4047 via a DMA channel
  • the A/D conversion process can include converting analog signals to digital signals represented as 8-bit (or gray scale) quantities As A/D converter technology improves, digital signals may be represented using more than 8 bits
  • Processor 4044 may also perform many timing and communication operations
  • Processor 4044 may, for example, control the illumination of LEDs 4022, the timing of image sensor 4032 and an analog-to-dig ⁇ tal (A/D) converter 4036, the transmission and reception of data to and from a processor external to reader 4010, through an RS-232, a network such as an Ethernet or other packet-based communication technology, a serial bus such as USB, and/or a wireless communication link (or other) compatible I/O interface 4037
  • Processor 4044 may also control the outputting of user perceptible data via an output device 4038, such as a beeper,
  • Fig 56 is a flow chart 1 100 showing a process for operating a system having an adjustable focus system comprising feedback, for example a system having components as described in Fig 53
  • the process begins at step 1 1 10, where a command to capture an image is generated, for example by a user depressing a trigger, or by an automated system issuing a capture image command in response to a specified condition, such as an ob j ect being sensed as coming into position for imaging
  • a specified condition such as an ob j ect being sensed as coming into position for imaging
  • Focus assessment can comprise comparison of the image quality with a specified standard or condition, such as the sharpness of contrast at a perceived edge of a feature in the image, or other standards
  • Another procedure for performing an auto focus operation using a flatness metric includes the following steps [00285] 1 Capturing a gray scale image ( ⁇ e , capture an image with the hand held reader and digitize the image using at least two bit resolution, or at least 4 discrete values),
  • the sampled image can be the captured image if it is a windowed frame comprising image data corresponding to selectively addressed pixels
  • the flatness of an image refers to the uniformity of the distribution of different gray scale values in the histogram
  • a flat distribution is one with little variation in numbers of observations at different gray scale values
  • poorly focused images will be "flatter” than better focused images, i e there will be a relatively even incidence of gray scale values over the range of gray scale values
  • a histogram for a well focused image has many pixels with high gray scale values, many pixels with low gray scale values, and few pixels in the middle
  • the use of historical information for various types of images, such as bar codes, including information encoded in look up tables, or information provided using the principles of fuzzy logic, is contemplated
  • step 1 130 the outcome of the focus assessment is compared to an acceptable criterion, such as sharpness (or contrast change) of a specified amount over a specified number of pixels Images that are digitized to higher digital resolutions (e g , using a range defined by a larger number of bits) may support more precise determinations of acceptable focus If the result of the assessment of focus is negative, the process proceeds to step 1 140, where the focus of the lens 920 of Fig 53, is modified After adjusting the focus, the operation of the process returns to step 1 1 10, and a new image is captured, and is assessed When an image is captured that is found to have suitable focus, the process moves from step 1 130 to step 1 150, wherein the image with suitable focal properties is processed, and a result is made available to a user or to the instrumentality that commanded the capturing of the image, and/or the result is stored in a memory Optionally, as indicated at step 1 160, the system can be commanded to obtain another image that is to loop back to the step 1 1 10, and to
  • Fig 57 is a flow chart showing a process for operating a system having an adjustable focus system that does not comprise feedback
  • a command to capture an image is generated, for example by a user depressing a trigger, or by an automated system issuing a capture image command in response to a specified condition, such as an object being sensed as coming into position for imaging
  • the lens 920 is driven with a first fluid lens control signal corresponding to a first condition, such as a default condition, for example using a voltage applied to the lens 920 that causes the lens 920 to operate by approximation with focal position q l of 7 inches
  • the applied voltage to focus at 7 inches is zero applied volts
  • an image is captured and processed at step 4220
  • the information retrieved from the captured image is examined to determine if a valid decoding of a bar code has been achieved If the decoding is valid, the information or data represented by the decoded image is reported as indicated at step 4
  • step 4230 the fluid lens control signal applied to the lens 920 is adjusted to a first alternative value, for example a voltage that causes the lens 920 to focus by approximation at a distance q2 of 30 cm
  • a first alternative value for example a voltage that causes the lens 920 to focus by approximation at a distance q2 of 30 cm
  • an image is captured and processed at step 4235
  • the information retrieved from the captured image is examined to determine if a valid decoding of a bar code has been achieved If the decoding is valid, the information or data represented by the decoded image is reported as indicated at step 4260, and the process stops, as indicated at step 4270
  • step 4240 If at step 4240 it is determined that a good decode has not been achieved, the process continues to step 4245, at which time the fluid lens control signal applied to the lens 920 is adjusted to a second alternative value, for example a voltage that causes the lens 920 to focus by approximation at a distance q3 of 100 cm Using this focal condition, an image is captured and processed at step 4250 At step 4255, the information retrieved from the captured image is examined to determine if a valid decoding of a bar code has been achieved If the decoding is valid, the information or data represented by the decoded image is reported as indicated at step 4260, and the process stops, as indicated at step 4270 If a valid decoding of a bar code is still not achieved, the process returns to step 4215, and the process is repeated to try to identify a valid bar code value In other embodiments, after a specified or predetermined number of iterative loops have occurred without a successful outcome, or after a specified or predetermined time elapses, the process can be abor
  • Figs 60 and 61 are drawings of hand held readers that embody features of the invention
  • Fig 60 shows a hand held reader 4500 comprising a case having a substantially linear shape
  • the handheld reader 4500 comprises circuitry as has been described with regard to Fig 55, including data processing capability and memory
  • the hand held reader 4500 comprises an input device 4510, such as a key pad, for use by a user, one or more buttons of which may also be used as a trigger 4534 to allow a user to provide a trigger signal
  • the hand held reader 4500 comprises an output device 4512, such as a display, for providing information to a user
  • the display 4512 comprises a touch screen to allow a user to respond to prompts that are displayed on the display 4512, or to input information or commands using any of icons or graphical symbols, a simulated keypad or keyboard, or through recognition of handwritten information
  • Hand held reader 4500 can also comprise a touch pad or touch screen that can display information as an output and accept information as an input, for example displaying one or more
  • Fig 61 shows another embodiment of a hand held reader 4550 which comprises components as enumerated with respect to hand held reader 4500, including specifically input 4510, output 4512, image engine and fluid lens 4514, card reader 4520, radio 4530, and RFI D transceiver 4532
  • the handheld reader 4550 comprises circuitry as has been described with regard to Fig 55, including data processing capability and memory
  • the case 4560 comprises a "pistol grip" or a portion disposed at an angle, generally approaching 90 degrees, to an optical axis of the imaging engine and fluid lens of the reader 4550
  • Hand held reader 4550 also comprises a trigger 4534, for example situated on the pistol grip portion of the reader 4550, and located so as to be conveniently operated by a finger of a user
  • Hand held reader 4550 also comprises a cable or cord 4570 for connection by wire to a base station, a computer-based data processing system, or a point of sale apparatus Alternately reader 4550 may communicated to a base station by means of
  • the hand held readers 4500 and 1550 are deployed at a fixed location, for example by being removably secured in a mount having an orientation that is controlled, which may be a stationary mount or a mount that can be reoriented Examples of such uses are in a commercial setting, for example at a point of sale, at the entrance or exit to a building such as an office building or a warehouse, or in a government building such as a school or a courthouse
  • the hand held readers of the invention can be used to identify any object that bears an identifier comprising one or more of a bar code, a magnetic stripe, an RFID tag, and a semiconductor memory
  • the hand held reader 4500, 4550 can be configured to operate in either a "decode mode” or a "picture taking" mode
  • the hand held reader 4500, 4550 can be configured so that the decode mode and picture taking mode are user-selectable
  • the reader can be configured to include a graphical user interface (GUI) for example on a touch pad or key pad that is both an input and an output device as depicted in Figs 60 and 61 enabling a user to select between the decode mode and the picture taking mode
  • GUI graphical user interface
  • the decode mode is selected by clicking on an icon displayed on a display such as display 4512 of Fig 60 whereby the reader is configured with a decode mode as a default
  • the mode of operation can be set by a communication from a remote device, or by default upon initial activation of the reader, as part of a power-up sequence
  • the reader is configured to operate in the decode mode on the next (
  • the "picture taking mode" is selected is selected by clicking on icon (which can be a toggle switch)
  • icon which can be a toggle switch
  • hand held reader 4500, 4550 is configured in a "picture taking mode" as the default mode
  • the hand held reader 4500, 4550 is configured to operate in the "picture taking mode" on the next (and subsequent) activation of trigger 4534 to generate a trigger signal
  • the hand held reader 4500, 4550 in response to the generation of the trigger signal captures an image and outputs an image to one or more of a memory, to a display 4512, or to a remote device
  • the hand held reader 4500, 4550 can be configured so that when the image capture mode is selected, the hand held reader 4500, 4550 avoids attempting to decode captured images It is understood that in the process of capturing an image for decoding responsively to receipt of a trigger signal, the hand held reader 4500, 4550 may capture a plurality of "test" frames, these may be full frames or only partial frames as discussed above, for use in establishing imaging parameters (e g , exposure, gain, focus, zoom) and may discard frames determined after decode attempts to not contain decodable symbol representations Likewise in the process of capturing an image for image output responsively to receipt of a trigger signal in a picture taking mode, the hand held reader 4500, 4550 may capture test frames, these may be full frames or only partial frames as discussed above, for use in establishing imaging parameters and may also discard images that are determined to be unsuitable for output It is also understood that in the "picture taking mode" the images captured may be archived for later analysis, including decoding of bar codes or other encode
  • the hand held reader 4500, 4550 displays a plurality of icons (at least one for decode mode and one for picture taking mode) whereby activation of an icon both configures the hand held reader 4500, 4550 to operate in the selected operating mode (decoding or picture taking) and results in a trigger signal automatically being generated to commence an image capture/decode (decode mode) or image capture/output image process (picture taking mode)
  • the trigger 4534 need not be actuated to commence image capture after an icon is actuated
  • Fig 62 is a diagram 4600 of a handheld reader of the invention in communication with a computer
  • a hand held reader 4550 of the type described hereinabove is connected by way of a cable 4570 to a computer 4610, which in the embodiment depicted is a laptop or portable computer
  • the computer 4610 comprises the customary computer components, including an input 4612, which may include a keyboard, a keypad and a pointing device such as a mouse 4608, an output 4614 for use by a user, such as a display screen, and software 4630 recorded on one or more machine-readable media
  • Examples of software that operate on the computer 4610 are a program 4632 that provides a quick view of the image as "seen” by the image engine and fluids lens in the hand held reader 4550 on the display 4614 of the computer 4610, and a interactive program 4634, for example provided on a machine readable medium, (not shown) that allows a user to control the signal (such as a voltage or electric potential) applied to the
  • Fig 62 shows a target at each of three distances or positions relative to the hand held reader 4550
  • the three targets lie along a single optical axis at discrete, different distances
  • the three targets 1620, 1622, 1624 lie at the same distance along distinct optical axes relative to hand held reader 1550
  • both the distances between the hand held reader 4550 and the targets are distinct, and the optical axes from the hand held reader 4550 to the targets are also distinct
  • Each target 1620, 1622, 1624 presents an object, such as a known test pattern of defined geometry, that the hand held reader 4550 can image
  • the observed control signal such as a voltage or impressed electric potential
  • Fig 63 is a flow chart 1700 of a calibration process useful for calibrating an apparatus embodying features of the invention
  • the calibration is initiated, as shown at step 1705, by initializing the system, including performing all power-on-sequence tests to assure that the system components are operating properly
  • a test target bearing a pattern or encoded symbol is positioned at a first test position When in the first test position, the target will in general be at defined distance and orientation relative to the hand held reader comprising a fluid lens
  • the fluid lens control signal (which in some embodiments is a voltage) is adjusted to obtain an acceptable, and preferably an optimal, focus condition for the target
  • the distance and orientation of the target and the fluid lens control signal parameters are recorded for future use in a non-volatile memory, for example in a table
  • the number of iterations is limited only by the amount of time and effort one wishes to expend performing calibration steps, and the amount of memory available for recording the calibration parameters observed
  • a calibration according to the flow diagram of Fig 63 would include performing calibration steps as described by steps 1710, 1715 and 1720 at three distinct positions for the target
  • the information obtained in calibration tests can be used when operating the corresponding imager (or in some instances, another imager of similar type) either by using the calibration information as an initial setting for operation in a closed loop mode as explained in connection with Fig 56, or as fixed operating conditions for discrete points in an open loop operating mode as explained in connection with Fig 57
  • Fig 64 is a diagram 1800 showing calibration curves for a plurality of exemplary hand held readers
  • the horizontal axis 1802 represents a fluid lens control signal parameter, such as voltage
  • the vertical axis 1804 represents an optical property of the fluid lens, such as optical power
  • three curves 1 810, 1 812, 1814 are shown, each curve representing a response (e g , optical power) of a specific fluid lens to an applied fluid lens control signal (e g , voltage)
  • the curve 1810 representing the behavior of a first fluid lens, reaches an optical power P 1820 at an applied voltage V l 1830
  • other fluid lenses may behave slightly differently, such that a second fluid lens, represented
  • Fig 65 is a diagram showing an embodiment of a power supply 1900 suitable for use with hand held readers
  • the first order electrical equivalent circuit for a fluid lens is a simple capacitor
  • a load 1910 represents in one embodiment a capacitive load to a power supply, generally 1920 Because the load is capacitive, the net power consumed is in general small
  • the power supply 1920 of Fig 65 is one possible embodiment, which is described first at a high level
  • the output of this power supply can be used as input to the commutator shown in Fig 58 comprising switches 4310, 4312, 4314, and 4316
  • a power source such as a 6 volt battery 1922, is adequate for operation of the supply
  • the voltage of the power source may be increased using a DC-to-DC converter comprising a switcher IC 1930 having a sensing terminal, a controller for a switch 1940, (such as a transistor) and an inductor 1935 (which may be provided externally to the switcher)
  • the sense terminal in some embodiments is connected to a voltage
  • Figs 67-69 are cross-sectional drawings showing an exemplary fluid lens 2100 with a mount comprising an elastomer for a hand held reader Such elastomers are made by Chome ⁇ cs North America, Parker Hannifin Corp , 77 Dragon Court, Woburn, MA 01801
  • a fluid lens 21 10 is shown with a solid body 21 12 in the form of a ring, and electrical contacts 21 14, 21 16 disposed on opposite sides thereof
  • the fluid lens body 21 12 is made of metal, and can also represent one of the contacts 21 14, 21 16, the other contact being insulated from the metal body 21 12
  • the body 21 12 is made from, or comprises, a non-conducting substance
  • the fluid lens body 21 12 is shown mounted in a holder 2120
  • the holder 2120 is tubular and has an internally threaded surface 2130 and a partially closed end 2132 having defined therein an aperture of sufficient size not to occlude the optically active portion of the fluid lens
  • the fluid lens body 21 12 is held in place by a threaded retainer ring 2122 that threadedly mates with the internally threaded surface 2130 of the holder 2120
  • the holder 2120 and retainer ring 2122 are made of an insulating material
  • an elastome ⁇ c material 2140, 2142 is provided in the form of an "O" ring or an annular washer, so that the fluid lens is supported in a desired orientation, without being subjected to excessive compressive forces or to mechanical disturbances that can be accommodated by the elastome ⁇ c ring 2140, 2142
  • a single elastome ⁇ c ring 2140 or 2142 is provided on one side
  • the present invention also deals with the deleterious effects of image smear caused by hand jittering or hand motion in a hand held imager or reader
  • Image smear has been one of the major sources for image quality degradation
  • Image smear and similar degradation mechanisms cause a reduced decode rate in a barcode reading application or a reduced contrast and a blurry image in an image capturing application
  • hand jitter or hand motion can cause image degradation that may be severe enough to prevent the image from being processed correctly
  • Fig 70 is a diagram illustrating a prior art variable angle prism as disclosed in U S Patent No 6,734,903 to Takeda, et al (hereinafter "the '903 patent")
  • the apparatus disclosed employs two angular velocity sensors, two angular sensors, two actuators and a variable angle prism with a lens system to form an anti-shaking optical system
  • This type of optical system is widely used in hand held video camcorders to correct the hand jittering effect
  • drawbacks including 1 higher cost due to many parts, 2 slow response time due to the use of mechanical actuators, 3 lower reliability due to moving parts, 4 the use of a separate auto-focusing electro-mechanical subsystem that further increases the cost and system complexity, and 5 the use of mechanical components that increases the complexity and difficulty of assembly
  • variable angle prism As is expressed in the following 1 1 paragraphs
  • a camera shake is a phenomenon in which photographed images move vertically or horizontally while a user is performing photographing by holding a video camera in his or her hands, since the hands or the body of the user slightly moves independently of the user's intention Images thus photographed can give a viewer considerable discomfort when reproduced on a television monitor or the like
  • VAP variable angle prism
  • a VAP 2204 is constituted by coupling two glass plates 2204a and 2204b via a bellows- like spring member 2204c and sealing an optically transparent liquid 2204d in the space surrounded by the two glass plates 2204a and 2204b and the spring member 2204c Shafts 2204e and 2204f provided in the glass plates 2204a and 2204b are connected to an actuator 2203 for horizontal driving and an actuator 2208 for vertical driving, respectively Therefore, the glass plate 2204a is rotated horizontally, and the glass plate 2204b is rotated vertical ly
  • VAP 2204 is described in Japanese Patent Laid-Open No 2- 12518 and so a detailed description thereof will be omitted
  • a horizontal angular velocity sensor 2201 detects an angular velocity caused by a horizontal motion of the image sensing apparatus resulting from a camera shake or the like
  • a control unit 2202 performs an arithmetic operation for the detection signal from the angular velocity sensor 2201 such that this horizontal motion of the image sensing apparatus is corrected, and detects and supplies an acceleration component to the actuator 2203
  • This actuator 2203 drives the glass plate 2204a of the VAP 2204 horizontally
  • the rotational angle of the glass plate 2204a which can be horizontally rotated by the actuator 2203 is detected by an angle sensor 2205
  • the control unit 2202 performs an arithmetic operation for this detected rotational angle and supplies the result to the actuator 2203
  • a vertical angular velocity sensor 2206 detects an angular velocity caused by a vertical motion of the image sensing apparatus resulting from a camera shake or the like
  • a control unit 2207 performs an arithmetic operation for the detection signal from the angular velocity sensor 2206 such that this vertical motion of the image sensing apparatus is corrected, and detects and supplies an acceleration component to the actuator 2208
  • This actuator 2208 drives the glass plate 2204b of the VAP 2204 vertically
  • the rotational angle of the glass plate 2204b which can be vertically rotated by the actuator 2208 is detected by an angle sensor 2209
  • the control unit 2207 performs an arithmetic operation for this detected rotational angle and supplies the result to the actuator 2208
  • An image sensing optical system 2210 forms an image of an object to be photographed on an image sensor 221 1
  • This image sensor 221 1 is constituted by, e g , a CCD
  • a two dimensional solid state CCD is used in conventional image sensing apparatuses such as video cameras
  • An output from the image sensor 221 1 is output to a recording apparatus or a television monitor through a signal processing circuit (not shown)
  • the actuators move the VAP horizontally and vertically to refract incident light, thereby performing control such that the image of an object to be photographed does not move on the image sensing plane of the image sensor Consequently, the camera shake is corrected
  • a fluid lens provided with additional components to counteract involuntary motions (“an anti-hand-jittering fluid lens”) combines the auto-focusing and variable angle prism functionality into a single low cost component that has no moving parts, and that provides fast response time
  • Fig 71 is a cross-sectional diagram 2300 of a prior art fluid lens that is described as operating using an electro-wetting phenomenon
  • the fluid lens 2300 is a substantially circular structure
  • the fluid lens comprises transparent windows 2302, 2304 on opposite sides thereof
  • a drop of conductive fluid 2360 such as water
  • a drop of conductive fluid 2370 possibly including dissolved electrolytes to increase conductivity, or to adjust the density of the conductive fluid to match the density of another fluid 2370 that is immiscible with the conductive fluid (such as oil)
  • a surface such as a window
  • a ring 2310 made of metal, covered by a thin insulating layer 2312 is adjacent the water drop
  • a voltage difference is applied between an electrode 2320 (that can also be a ring) and the insulated electrode 2310, as illustrated by the battery 2330
  • an insulating spacer 2335 (not shown) is located between the rings 2310 and 2320 The voltage difference modifies the contact angle of the liquid drop
  • the fluid lens uses two is
  • the current invention uses the principle of altering the interface shape between two fluids and provides another voltage (or other suitable fluid lens control signal) to control an optical tilt of the fluid interface to adjust an exit optical axis angle or direction relative to the fluid lens
  • Another application of such adjustment of the exit optical axis angle is to provide a mechanism and method to compensate the angular movement caused by hand-jittering or hand motion
  • Fig 72 is a cross sectional diagram 2400 showing an embodiment of a fluid lens configured to allow adjustment of an optical axis
  • Fig 73 is a plan schematic view of the same fluid lens
  • Fig 73 indicates that the two metal ring electrodes 2310, 2320 of the prior art fluid lens shown in Fig 71 have been divided into a plurality of segments, for example four arc pairs (2410a, 2420a), (2410b, 2420b), (2410c, 2420c) and (241 Od, 242Od)
  • a plurality of controllable signal sources such as voltage sources V l , V2, V3, and V4, are provided, such that each controllable signal source can impress a signal on a selected pair of electrodes independent of the signal applied to any other electrode pair
  • V l , V2, V3, and V4 are provided, such that each controllable signal source can impress a signal on a selected pair of electrodes independent of the signal applied to any other electrode pair
  • V l , V2, V3, and V4 to
  • V3 Vf - dv
  • V4 Vf- dh
  • Fig 74 is a schematic diagram 2500 showing the relationships between a fluid lens and various components that allow adjustment of the optical axis direction
  • the optical axis control system comprises a horizontal angular velocity sensor 2510, a control module 2512 to generate horizontal tilt voltage dh, a vertical angular velocity sensor 1520, a control module 2522 to generate vertical tilt voltage dv, an auto-focusing control module 2530 to generate a focusing voltage Vf, a distributor module 2540 to synthesize the control voltages to control the fluid lens module 2400 to accommodate or to correct for hand jittering Alternately when the axis of the optical system changes orientation, the image on the image sensor will move
  • the processor can extract the magnitude and direction of motion of the object that was not expected to move This can be used as input to the correction circuit
  • the angular velocity sensors 2510 and 2520 are commercially available low cost solid-state gyro-on-a-chip products, such as GyroChips manufactured by BEI Technologies, lnc , One Post Street, Suite 2500 San Francisco, CA 94104
  • the GyroChip comprises a one piece, quartz micromachined inertial sensing element to measure angular rotational velocity
  • U S Patent No 5,396,144 describes a rotation rate sensor comprising a double ended tuning fork made from a piezoelectric material such as quartz These sensors produce a signal output proportional to the rate of rotation sensed
  • the quartz inertial sensors are micromachined using photolithographic processes, and are at the forefront of MEMS (Micro Electro- Mechanical Systems) technology These processes are similar to those used to produce millions of digital quartz w ⁇ stwatches each year
  • MEMS Micro Electro- Mechanical Systems
  • the two metal rings 2410 and 2420 of Fig 73 into more than four symmetric arc pairs to create more smooth tilt fluid lens
  • one of the embodiments can have 12 symmetric arc pairs layout in a clock numeric topology All the system components shown in Fig 74 will be the same except that the output of distributor 2540 will have 12 voltage control outputs to drive the 12 arc pairs of the fluid lens module
  • Fig 75 is a schematic diagram of an alternative embodiment of a fluid lens 2600
  • Fig 76 is a schematic diagram of an alternative embodiment of a distributor module 2640
  • a distributor module 2640 will select a pair of connect points, for example 2612c and 2612i, according to the vector (dh, dv) to apply a tilt voltage tv to the pair of connect points 2612c and 2612i that are disposed symmetrically about a center 2630 of the fluid lens
  • the voltage signals that will be applied are (Vf+tv, Vf-tv)
  • the tilt voltage tv is a function of (dh, dv) and can be predetermined by a mathematical formula or a lookup table
  • the voltage can be made to drop uniformly from point 2612c to point 2612i along the
  • Fig 77 is a schematic diagram showing the relationship between a fluid lens 2700 and a pair of angular velocity sensors
  • two of the angular velocity sensors 2710, 2720 can be integrated with the fluid lens 2700 to form an integrated module 2730
  • the angular velocity sensors 2710 and 2720 are arranged in an orthogonal relationship to detect two orthogonal angular velocities
  • the entire control circuitry as shown in Fig 74 can also be integrated into the module 2730
  • An advantage of this embodiment is ease of mounting the module 2730 No vertical or horizontal alignments are required
  • the module will automatically adjust the lens tilt angle according to the output voltages dh and dv provided by the angular velocity sensors 2710 and 2720
  • Figs 78-82 are cross-sectional diagrams of another prior art fluid lens that can be adapted for use according to the principles of the invention
  • Fig 78 is a cross-sectional view of a prior art fluid lens having no control signal applied thereto and exhibiting divergence of transmitted light
  • Fig 79 is a cross-sectional view of a prior art fluid lens having a control signal applied thereto and exhibiting convergence of transmitted light
  • Figs 80, 81 , and 82 are cross-sectional images of fluid lenses having convex, flat and concave interface surfaces as viewed from a position above each lens, respectively
  • a device comprising a fluid lens, an image sensor, and a suitable memory
  • the device can further comprise a computation engine, such as a CPU and an associated memory adapted to record instructions and data, for example for processing data in one or more frames
  • the device can additionally comprise one or more control circuits or control units, for example for controlling the operation of the fluid lens, for operating the image sensor, and for controlling sources of illumination
  • there is a DMA channel for communicating data among the image sensor, the CPU, and one or more memories
  • the data to be communicated can be in raw or processed form
  • the device further comprises one or more communication ports adapted to one or more of hard- wired communication, wireless communication, communication using visible or infra-red radiation, and communication employing networks, such as the commercial telephone system, the Internet, a LAN, or a WAN
  • the device can obtain a plurality of frames of data, a frame being an amount of data contained within the signals that can be extracted from the imager in a single exposure cycle
  • the device can assess the quality of each of the frames against a selection criterion, which can be a relative criterion or an absolute criterion
  • selection criteria are an average exposure level, an extremum exposure level, a contrast level, a color or chroma level, a sharpness level, a decodability level of a symbol within a frame, and a level of compliance of an image or a portion thereof with a standard
  • the device can be programmed to select a best or a closest to optimal frame from the plurality of frames, and to make that frame available for display, for image processing, and/or for data
  • the fluid lens can be operated so as to change its focal length over a range of focal lengths, from infinity to a shortest focal length
  • the device can obtain one or more frames of data for each focal length that is selected, with the information relating to each focal length being recorded, or being computable from a defined algorithm or relationship, so that the focal length used for each image can be determined
  • the distance from the device to the object of interest in the frame can be determined from the information about the focal length setting of the fluid lens corresponding to that frame
  • the distance may be taken as the average of the two focal lengths corresponding to the two frames, or alternatively,
  • apparatus and methods are provided to counteract changes in the environment that surrounds an apparatus comprising a fluid lens
  • the apparatus additionally comprises a temperature sensor with a feed back (or feed forward) control circuit, to provide correction to the fluid lens operating signal as the temperature of the fluid lens (or of its environment) is observed to change
  • Feedback systems rely on the principle of providing a reference signal (such as a set point) or a plurality of signals (such as a minimum value and a maximum value for a temperature range) that define a suitable or a desired operating parameter (such as a temperature or a pressure), and comparing a measured value of the parameter to the desired value When a deviation between the observed (or actual) parameter value and the desired parameter value is measured, corrective action is taken to bring the observed or actual value into agreement with the desired parameter value
  • a heater such as a resistance heater
  • a cooling device such as a cooling coil carrying a coolant such as water
  • the apparatus is made to operate at the desired set point, or within the desired range
  • Feedback loops can be provided using either or both of digital and analog signal processing, and using one or more of derivative, integral and proportional (“D-I-P”) controllers
  • a feed-forward system can be used, in which a change (or a rate of change) of a parameter such as actual or observed temperature is measured Corrective action is taken when it is perceived that a condition outside of acceptable operating conditions likely would be attained if no corrective action were to be applied and the observed change (or rate of change) of the parameter were allowed to continue unabated for a further amount of time
  • Feed-forward systems can be implemented using either or both of digital and analog signal processing In some systems, combinations of feedback and feed-forward systems can be applied In some embodiments, multiple feedback and feed-forward controls can be implemented
  • the operating parameter such as temperature
  • the apparatus comprising a fluid lens, or of the environment in which it is situated
  • the observed parameter is compared to one or more pre-defined values
  • the one or more predefined values may be fixed (such as a maximum tolerable temperature above which a substance begins to degrade at one atmosphere of pressure) or the one or more predefined values may depend on more than one parameter, such as the combination of pressure and temperature, for example using relationships in a pressure-temperature-composition phase diagram (for example, that a substance or chemical composition in the fluid lens apparatus undergoes a phase change if the pressure and temperature vary such that a phase boundary is crossed, or undergoes a change from covalent to ionic character, or the reverse)
  • a system comprising a fluid lens additionally comprises a non- adjustable lens component configured to correct one or more specific limitations or imperfections of the fluid lens, such as correcting for color, spherical, coma, or other aberrations of the fluid lens itself or of the fluid lens in conjunction with one or more other optical components
  • a fluid lens may exhibit dispersive behavior or color error
  • a second optical element is added that provides dispersion of the sign opposite to that exhibited by the fluid lens, so as to correct the dispersive error introduced by the fluid lens
  • the dispersive element is a diffraction element, such as an embossed grating or an embossed diffractive element
  • different optical materials have different dispersive characteristics, for example, two glass compositions can have different dispersion, or a composition of glass and a plastic material can have different dispersion
  • the aberrations that are possible in a fluid lens can in principle be of any order, much as the aberrations that are possible in the lens or the cornea of a human eye
  • Both a human eye and a fluid lens operate using interfaces between two or more dissimilar fluids
  • membranes that are used to apply forces to the fluids adjacent the membranes, by application of muscle power controlled by signals created by the nervous system
  • forces that are applied in some instances to the fluid or fluids directly by electromagnetic signals, and in some instances by forces applied to transparent membranes that are adjacent the fluids
  • Both kinds of systems can be affected by external forces, such as the force of gravity and other accelerative forces, changes in ambient or applied pressure, and changes in ambient or applied temperature
  • a calibration tool, process, or method for calibrating a fluid lens As one example, a system comprising a fluid lens is operated at one or more known conditions, such as one or more magnifications or one or more focal lengths For each known operating condition, an operating parameter, such as a value of the driving voltage, is observed or measured The observed or measured data is stored in a memory The data in memory is then used to provide calibration data for application to the operation of the fluid lens
  • an inertial device such as an accelerometer is provided to determine an orientation of a fluid lens, which orientation information is used to self-calibrate the fluid lens
  • Gravitational and other accelerative forces can cause fluids to move and change shape at a free boundary, or a boundary where two fluids come into mutual contact
  • Gravitational and other accelerative forces can cause fluids to move and change shape at a free boundary, or a boundary where two fluids come into mutual contact
  • the fluid lens in yet an additional embodiment, is operated to provide corrective properties with regard to such distortions as may be caused by vibration, location or orientation of the lens, chromatic aberration, distortions caused by higher order optical imperfections, and aberrations induced by environmental factors, such as changes in pressure
  • the fluid lens may in some instances be subjected to various distorting forces or to forces that cause degradation of the operation of the fluid lens from that which is desired
  • the fluid lens may have inherent imperfections, such as chromatic aberration or higher order optical imperfections
  • It is possible to analyze such optical imperfections in various ways, such as the use of a calibrated imaging system comprising a source, at least one image sensor, and hardware and/or software configured to analyze optical information to assess whether errors or imperfections exist in an optical component under test
  • the calibrated imaging system in some instances can be a laboratory setting in which highly sophisticated equipment is employed to perform tests
  • the calibrated test system can comprise a source that
  • Applications for fluid lenses include their use in one or more types of camera, such as cameras in cell phones, use in higher quality digital cameras such as those having a high powered zoom lens, and use in cameras that can provide auto focus, and pan, tilt, and zoom (“PTZ") Panning is moving a camera in a sweeping movement, typically horizontally from side to side Tilting is a vertical camera movement, e g in a direction orthogonal to panning
  • PTZ pan, tilt, and zoom
  • PTZ pan, tilt, and zoom
  • a suitable power supply for driving the fluid lens is a square wave power supply that is biased to operate in the range 0 to V volts, where V is either a positive or a negative voltage, which may be thought of as a unipolar supply
  • power supplies that provide voltage signals having both positive and negative peak voltages of the order of one volt to hundreds of volts are provided
  • the output voltages are provided as square waves that are generated by a driver integrated circuit such as is commonly used to operate electroluminescent lamps, such as are found in cellular telephones
  • Fig 83 is a schematic block diagram showing an exemplary fluid lens driver circuit 2900
  • the circuit is powered by a battery supply 2910, typically operating in the range of 3 to 4 5 volts, although circuits operating with batteries of other voltages and also operating from fixed wall mount power supplies can be designed
  • a voltage reference 2920 is provided which may have associated with it a low drop out voltage regulator Input signals in the form of a clock signal (a frequency or a pulse train) and digital data line are provided to a I2C serial interface 2930 for control of this driver circuit by an external device, such as the microprocessor 4040 of Fig 55
  • the serial interface 2930 is in communication with a controller 2940 (such as a commercially available microcontroller) for coordinating the activities of the fluid lens driver circuit 2900, the oscillator 2960, to set the output frequency, and a digital-to-analog (DAC) converter 2950, to set the output voltage
  • the DAC is provided with a reference voltage by the voltage reference 2920 In some embodiments DAC
  • the controller 2940 is in communication with an oscillator 2960 that provides a timing signal This oscillator 2960 can be signaled to enter a power down state by a suitable signal communicated from an external source at 2962, which in some embodiments can be a user or can be another controller
  • the controllers contemplated herein are in general any microprocessor-based controller including a microcontroller, a microprocessor with associated memory and programmed instructions, or a general purpose digital computer
  • the controller 2940 is also in communication with a wave form generator 2945 that creates the square wave waveform for the bridge driver output stage 2980 The waveform generator 2945 also synchronizes the DAC transitions with the output waveform through the controller 2940
  • the output of the DAC 2950 sets the output voltage level of the high voltage generator 2970 such that the output voltage is proportional to the output of the DAC 2920, and thereby is configured to be controlled with high precision by a digital source such as a computer
  • appropriate feedback circuitry is contained in this portion of the circuit to keep the output voltage constant over a range of input voltage, load and environmental conditions
  • the high voltage created by the high voltage generator 2970 is an input to the bridge driver 2980
  • the high voltage generator has a stable output ranging from 0 Volts to approximately 40 Volts for the Va ⁇ optic ASM- 1000 fluid lens This generator may utilize an inductor 2972 and or capacitors to create the higher voltage However other circuit configurations might also be used, for example capacitive voltage multipliers
  • the bridge driver 2980 creates the high voltage switching signals OUTP and OUTM which drive the fluid lens 2995 In some embodiments, the output can be applied to a load such as fluid lens 2995 using the commutating circuit of Fig 58
  • the output to the fluid lens is a voltage signal that is wave shaped by the bridge driver using a wave form signal from the wave form generator
  • bridge driver should be understood as follows
  • the load is connected between two amplifier outputs (e g , it "bridges" the two output terminals)
  • This topology can double the voltage swing at the load, compared to a load that is connected to ground
  • the ground-tied load can have a swing from zero to the amplifier's supply voltage
  • a bridge-driven load can see twice this swing because the amplifier can drive either the + terminal of the load or the - terminal, effectively doubling the voltage swing Since twice the voltage means four times the power, this is a significant improvement, especially in applications where battery size dictates a lower supply voltage, such as in automotive or handheld applications
  • Figs 84 and 85 are diagrams that show an LED die 3010 emitting energy in a forward direction through a fluid lens 3020
  • the divergence of the emitted light is modified with the fluid lens
  • the divergence of the emitted light is modified because of the optical power of the fluid lens
  • the light exiting the fluid lens could be considered to approximate collimated light even though the light exiting the LED is diverging
  • the light may be focused on a smaller region
  • the power of the fluid lens has been reduced to approximately zero so that the divergence of the light emitted by the LED is substantially unchanged
  • the comparison of the light patterns in Figs 84 and 85 indicates that such systems can be used to control the coverage (in area) at a target of interest, for example a bar code that one is interested in reading with a hand held reader or imager
  • one or more windows on a reader or scanner may also be
  • Figs 87, 88, and 89 show diagrams of a laser scanner comprising a laser 31 10, a collimating lens 3120, and a fluid lens 3130 in various configurations
  • the fluid lens is configured to have a first optical power, a first focal length and a first principal beam direction
  • the light beam emanating from the fluid lens 3130 is focused to have a narrowest beam width at a plane 3140 situated at a first distance Dl from the fluid lens 3130
  • the fluid lens is configured to have a second optical power, a second focal length and a first principal beam direction
  • the light beam emanating from the fluid lens 3 130 is focused to have a narrowest beam width at a plane 3141 situated at a second distance D2 from the fluid lens 3130, such that D2 is greater than D l , and the first principal beam direction is not changed when the focal length of the fluid lens 3130 is changed
  • the fluid lens is configured to have a first optical power, a first optical power, a first optical power, a first optical direction
  • the present inventions are intended to take advantage of fluid lens zoom optical systems
  • Fluid zoom lens configurations can be used in bar code scanners to enable imaging of different bar codes at various distances from the bar code scanner
  • bar code scanners manufactured today often a large working distance is achieved by stopping down the lens aperture to increase the optical depth of field
  • this has two disadvantages
  • the lower SNR requires the operator to hold the reader still for longer period of time
  • the effect is that the bar code scanner has an increased sensitivity to hand motion
  • the user is more likely to become fatigued
  • Object distance measurements can be made if the range of, or the distance to, the object is known
  • a fluid lens system can be used to implement a range finding system
  • the fluid lens would be focused at a number of focus positions and the position with the best focus, as determined by any of a number of metrics, would be associated with that fluid lens position
  • the associated distance from the system for that specific fluid lens operating voltage can be determined
  • the magnification can be calculated and thus the object width associated with a given number of pixels at the imager is known or can be deduced
  • a system such as a bar code reader or imager can calculate the width of specific object features, such as bar code element widths or the dimensions of a package
  • a fluid lens variable aperture can be added to a bar code system
  • the aperture would be used in the portion of the optical system that receives light and would allow the system to optimally trade light efficiency against point spread function width and depth of field
  • the optical system will have a larger depth of field, but adversely the optical throughput of the system is reduced (i e , less light gets through the system) and the point spread function (proportional to the minimal element size that can be resolved) is also reduced
  • a bar code system is expected to be configured to initially have the optical system set for an optimum light throughput, and if a good read is not achieved then the aperture size could be reduced in order to extend the depth of field in an effort to decode any bar code pattern that may be within the bar code scanner field of view
  • a fluid lens is used as a variable aperture
  • a fluid lens is used as a variable aperture
  • One implementation of this use of a fluid lens involves adding a colorant to at least one of the fluids to make that fluid opaque in at least a region of an electromagnetic spectral range of interest, such as being opaque at a specified range in the visible spectrum Voltage is applied to the lens from a power supply such that the fluid lacking the colorant that absorbs in the specified region "bottoms" against the opposite window, thereby forming a clear aperture in that spectral range of interest
  • colorant can be added to the water component of an oil water fluid lens
  • the liquid lens can in some instances be configured to perform as a variable filter
  • the oil would not bottom against the opposite window, but would produce a thickness of the water that is essentially constant as a function of radius across a portion of the window This thickness would be varied by varying the applied voltage
  • the voltage-controlled thickness of the light-absorbing water would thereby determine the amount of light passing through the fluid filter If the colorant has light absorbing characteristics in specific wavelengths, then the amplitude of the light in these wavelengths passing through the fluid filter would be varied by varying the applied voltage
  • any given lens is optimized for a given focal length system
  • any given lens is optimized for a given focal length system
  • a lens is optimized for one combination of optical elements, it is not optimally configured when one of the lens surfaces is changed as would happen when a single fluid element is operated to change an optical parameter, such as a focal length
  • the combination of the first lens and the second lens can be optimized to minimize total system aberrations
  • corresponding changes in the settings of the second lens can be made to obtain an optimal combination
  • Machine-readable storage media that can be used in the invention include electronic, magnetic and/or optical storage media, such as magnetic floppy disks and hard disks, a DVD drive, a CD drive that in some embodiments can employ DVD disks, any of CD-ROM disks ( ⁇ e , read-only optical storage disks), CD-R disks ( ⁇ e , write-once, read-many optical storage disks), and CD-RW disks ( ⁇ e , rew ⁇ teable optical storage disks), and electronic storage media, such as RAM, ROM, EPROM, Compact Flash cards, PCMCIA cards, or alternatively SD or SDlO memory, and the electronic components (e g , floppy disk drive, DVD drive, CD/CD- R/CD-RW drive, or Compact Flash/PCMCIA/SD adapter) that accommodate and read from and/or write to the storage media
  • new media and formats for data storage are continually being devised, and any convenient,
  • the present invention is directed to a lens module containing a lens element and a force element
  • the lens element includes a deformable member comprising two surfaces, such as a deformable membrane, which may be elastically deformable, with at least one of the surfaces being in force communication with a fluid
  • force communication may be used herein because both of the surfaces may be in contact with a fluid, whereas only one of the fluids may be used to transmit force to the deformable membrane in order to selectively change the focal length, and/or the orientation of the optical axis, of the lens element (This fluid may also be considered the "working” fluid )
  • “force communication” can have the meaning that force transmitted to either the deformable member or the fluid will produce a substantially proportional response in the other, with “substantially proportional” meaning simply that the fluid and the deformable member are part of a closed system For example, if the needle of a large syringe could be inserted into an inflated balloon without popping it, motion of the s
  • both sides of the deformable member could be in contact with sealed volumes of fluid, but only one side would be in force communication with a working fluid, while the other side might be in contact with, or only facing, a fluid volume that is used for a purpose other than deforming the deformable member in order to change focal length and/or orientation of the optical axis, such as to prevent contamination of the membrane surface, or as a filter, or as an additional optical element
  • the sealed volume could contain both a liquid volume and a gaseous headspace, with the gas being in direct contact with the membrane rather than the liquid, possibly itself separated from the liquid by another membrane
  • the side of the deformable member that is in force communication with a sealed fluid volume may also be
  • the present application may also refer to an "optical path" in describing certain aspects of the present invention
  • an imaging system including an optical system and an imager
  • the optical axis is not blocked (as by a shutter, ins, lens cover, or otherwise), and if sufficient light is available, at any given moment the imager will be receiving an image representative of some object external to the imaging system
  • the optical path may be broadly defined as the path along which light rays travel from the external object, through the optical system, to the image sensor
  • the optical path is not necessarily bounded to include all of the light rays reaching the image sensor, but includes any portion thereof, up to and including the path along which any single light ray has traveled between the external object and the sensing area of the image sensor
  • a variable lens may comprise a deformable interface between two fluids having dissimilar optical indices
  • the shape of the interface can be changed by the application of force supplied by a force element so that light passing across the interface can be directed to propagate in desired directions
  • the optical characteristics of such lenses such as whether the lens operates as a diverging lens or as a converging lens, its focal length, and the orientation of its optical axis, can be changed, generally by changing a deformable element that functions as at least one face or surface of the lens among flat, convex, and concave profiles
  • the lens element may be a single component, such as a fluid-filled elastomer, polymer, or plastic, for example, a transparent oil-filled elastomer material which has an elastic memory
  • the lens element may be two or more components, with an optical fluid (such as water or oil) entrapped or sandwiched between a boundary layer, such as glass or plastic, and a deformable member, in which configuration the optical fluid and the deformable member would together comprise the lens element
  • suitable materials include polydimethylsiloxane, or PDMS, such as Sylgard® 184 silicone elastomer, available as a kit from Dow Corning Corporation, Midland, Michigan, USA
  • the membrane thickness may be selected based on factors such as the size of the lens module in question and may be, for example, from about 0 05 to about I mm, for example, 0 1 , 0 2, 0 3, or 0 4 mm
  • the overall size of the lens module of the present invention is not critical and may be varied depending on the size of the available components, the device into which it will be placed or assembled, and the needs of the user
  • the guidelines provided herein for the size of the lens module are with reference to the major dimension of a cross-section of the lens module (not merely the lens element) as viewed along the optical axis
  • the cross-section 5808 as viewed along the optical axis 5810 will be a circle, and the larger cross- sectional dimension will be the diameter 5806 of the circle (represented as a dotted line), there being no smaller cross-sectional dimension
  • the cross-section is elliptical, as where the lens element is itself elliptical and the housing conforms to that shape, the major dimension will be the major axis of the ellipse
  • the lens module will have a major dimension of from about 5, 7,
  • optical grade oils such as optical grade mineral oils
  • suitable optical fluid is Type A immersion oil, available from Cargille-Sacher Laboratories lnc , Cedar Grove, New Jersey, USA
  • Another suitable fluid is the Santovac® polyphenyl ether-based optical fluid SL-5267, available from Arch Technology Holding LLC , St, Charles, Missouri, USA Water may also be used, such as de-ionized water
  • the materials selected for the optical fluid, deformable member, and any boundary layer should have similar indices of refraction
  • the lens element includes a glass boundary layer, an optical fluid, and a deformable membrane
  • the closer the indices the less light will be lost to reflection
  • the indices will ideally be identical, and preferably will be within about +/- 0 001 to 0 01 , such as about 0 002
  • differences in the indices of refraction may be advantageous
  • the lens system containing a variable lens will then include a force element to cause the lens to vary, as by direct or indirect application of electrical, mechanical, hydraulic, pneumatic, thermal, magnetic, or other force
  • mechanical force is provided by the motion of a solid object, such as a piston, composed of, for example, metal or plastic
  • hydraulic force is produced by the motion of a liquid
  • pneumatic force is produced by the motion of a gas
  • thermal force is produced by a change in temperature
  • magnetic force may be produced by the motion of electric current through a wire
  • the force may be applied externally and/or internally to the fluid component that is used to transmit the force to the deformable member
  • the cylinder may contain a piston that is in sealed connection with the cylinder wall and which can be moved back and forth within the fluid to effect changes in the shape of the deformable member
  • the wall of the cylinder may be
  • the force element is capable of providing sufficient force to deform the deformable member and is operably coupled to that member in order to allow the force to travel from the force element to the deformable member
  • the force element may act directly on the deformable member, or on the fluid which will then act on the deformable member, but many variations on this are possible within the scope of the invention
  • the force element acts on a pressure element positioned on the side of the deformable member facing away from the working fluid, the pressure element generally having an annular shape and contacting an outer portion or circumference of the deformable member, as in the shape of a ring or washer, and the force element pushes or pulls on the pressure element, which in turn
  • a control system is provided to control the force element While the control system will generally be powered electrically rather than, for example, mechanically, it may further include hydraulic, pneumatic, mechanical, and/or magnetic control features depending on the nature of the force element(s) being used
  • the control system may be an electrical control system, which will control the electroactive polymer by controlling whether current or voltage is being supplied to the electroactive polymer, and by controlling the level or amount of such current or voltage, in order to control the deformation of the electroactive polymer
  • An electrical control system may also be used when the force element is a voice coil, with the level or amount and/or polarity of current or voltage controlling the strength and/or direction of the magnetic field generated in the voice coil
  • the control system may include pistons, pumps, valves, piezoelectric elements, and similar components to regulate aspects such as the volume, force, and direction of fluid being moved
  • the lens module may be configured with multiple force elements, each being energizeable on its own circuit, or, with one or more force elements each having multiple, separately energizeable circuits
  • the control system may control not only the formation and magnitude of convex and concave surfaces in the deformable member, but also the tilt of those surfaces
  • tilt refers to the possible combinations of pitch and yaw that may be used to configure the shape of the deformable member to have surface shapes other than symmetric to an axis normal to the surface of the deformable member when that surface is flat and passing through its center
  • Fig 131 in which focus fluid 5702 has been further represented as having convex surface 5704, shown as having an asymmetric shape in response to selective application of control signals to a multicircuit force element, such as that shown in Fig 120
  • the present invention is directed to variable lenses actuated by polymeric actuators, and to lens systems, optical systems, and devices containing such variable lenses
  • the present invention is directed to variable lenses actuated by force elements that are arranged symmetrically around the optical axis of such lenses, as will be further explained herein
  • the variable lens includes at least one component capable of changing focal length, and/or the orientation of an optical axis passing through it, by deforming in response to an applied force
  • the deformation may or may not be elastic, in the sense of the component returning to its original configuration if the applied force is removed or discontinued However, it is anticipated that in most uses it will be desirable for the component to return to its original configuration, and to accordingly be elastically deformable
  • Polymeric actuators including electroactive polymers, may be used as a source of mechanical force to change the interface in an adaptive lens
  • the phrase "polymeric actuators" is used herein to refer to a category of polymeric materials that respond to a change in electric stimulation, such as voltage, with physical movement
  • electroactive polymer materials available from Artificial Muscle, lnc , of Menlo Park, California, the ion conductive actuators and conducting polymer actuators available from EAMEX Corporation of Osaka, Japan, nano actuators/transducers and artificial muscles available from Environmental Robots lnc , of
  • a basic construct for a variable lens element is shown in Figs 89 and 90, in which the fluid is substantially optically clear, and at least a portion of the deformable membrane is also substantially optically clear
  • the membrane includes first and second surfaces, at least one of which is facing, and may be in direct contact with, the working fluid
  • Fig 89 the membrane is flat, while in Fig 90 the membrane has assumed a convex shape
  • the convex shape may result from positive pressure being exerted from the working fluid, and this pressure could result from reducing the volume of the fluid chamber, or by additional fluid being introduced into the fluid chamber However, it may also be accomplished by pressing the membrane, or a portion of the membrane, in the direction of the fluid, with the pressure being exerted against the side of the membrane facing away form the working fluid, as shown in Figs 91 and 92
  • Fig 91 shows fluid component 5002 in container 5004, which is in turn in housing 5006
  • the lens element may further include support or boundary element 5008
  • all elements present in a given lens system and lens module that he within the desired optical path of the system should be at least substantially optically clear
  • deformable member 5010, fluid component 5002, container 5004, and support or boundary element 5008 should all be at least substantially optically clear, in at least a central portion corresponding to at least a portion of the optical path for the lens system
  • Deformable member 5010 is adjacent to working fluid component 5002
  • Force elements 5014 are fixed at lower portions 5016, with upper portions 5018 adjacent pressure element 5020
  • Pressure element 5020 is in the form of a ring, washer, or similar annular shape, shown here in cross-section
  • force elements 5014 exert force downward, via portions 5018, on pressure element 5020
  • Pressure element 5020 presses deformable member 5010 in the direction of working fluid component 5002, resulting in the formation of convex portion 5022, as shown in Fig 93
  • the elasticity of deformable member 5010, and/or the dynamic of fluid component 5002 will cause the deformable member to return to substantially its pre-actuation shape of Fig 91
  • This illustration assumes that the deformable member is flat in its default state, and that actuation of the force elements cause it to present a curved surface, but it may readily be appreciated that Fig 92 could represent the default state, with actuation of the force elements producing the configuration of Fig
  • both surfaces of the deformable member will usually be facing, and often in direct contact with, a fluid
  • one surface will often be in contact with the ambient air
  • the other surface may be in contact with a working liquid, but it is possible to use a gas on both sides
  • any combination is possible, gas/gas, gas/liquid, liquid/gas, and liquid/liquid
  • at least one side of the deformable member will face, or be in contact with, a working fluid, as opposed to, for example, the ambient atmosphere
  • the force element introduces force in order to deform the deformable member and to thereby change the focal length and/or the orientation of the optical axis
  • the force element of the present invention may be disposed both symmetrically, and circumferentially, around a central axis of the deformable member
  • symmetry is not determined by the physical positioning or location of the force element, but by how the force itself is exerted with respect to the deformable member
  • a symmetrically disposed force element is one which is capable of either exerting a continuous force around the entire circumference of the deformable member, as represented by the shaded inner annulus in Fig 93, or of exerting discontinuous forces that are regularly spaced around the circumference, as suggested by Figs 94-96
  • 5030 represents the surface of the deformable membrane and shaded area 5032 represents the area on which force is exerted around the circumference of that membrane through the force element (not shown)
  • the force element may reside inside the lens element, or it may comprise one or more walls of the lens element, or it may reside outside the lens element Combinations of these configurations are also possible Further, “circumferential” refers to the fact that the lens element will have a perimeter that is closed, and which may consist entirely of curves (as in a circle, oval, egg, hourglass, or ellipse) or of line segments (as in a triangle, rectangle, or other regular or irregular polygon) The perimeter may also combine curves and line segments
  • the lens may alternatively be a single component, rather than a combination of a working fluid and a deformable member
  • the lens is a deformable, optionally elastically deformable, solid, such as a silicone that is optically clear in at least a portion
  • Figs 97-98 Fig 97 depicts a disc of deformable solid 5040, on which rests a washer-shaped pressure element 5042
  • pressure has been exerted on pressure element 5042, causing it to move downward
  • Solid 5040 is not free to simply move proportionally away from the direction of the force - for example, it may rest on a glass surface, and be circumferentially constrained by a side wall - and therefore pressure element 5042 presses down into solid 5040, causing the formation of convex surface 5044
  • Figs 97 and 98 are illustrative only, and several alternatives are available
  • pressure element 5042 may be pulled downward by a force acting from below the level of the deformable member
  • pressure element 2 may surround at least a portion of the circumference of solid 1 and then have its diameter reduced in a compressing or squeezing action to create convex portion 5044
  • at least a portion of the circumference of solid 5040 it is meant that pressure element 5042 would extend completely around the circumference, but may have a height less than that of the outer wall of solid 5040, although this is possible
  • Fig 99 shows an embodiment in which a relatively narrow, washer-shaped pressure element 5046 extends around the outer wall of the deformable member
  • Fig 100 shows an embodiment in which a relatively broad washer-shaped pressure element 5048 is used
  • Fig 101 showing lens element 5100 having piston 5102, fluid 5104, and deformable member 5108, shown in three configurations, flat (4a), convex (4b), and concave (4c)
  • the initial mechanical force is generated when piston 5102 starts to move in response to electrical energy being supplied to a motor driving the piston (not shown)
  • the mechanical energy of the moving piston is then transmitted to the fluid with which it is in direct contact, transmitting force from the piston to the fluid immediately surrounding the piston head This force is in turn propagated through the fluid until it reaches the deformable membrane
  • the mechanical force causing deformation of the membrane propagates through three fluid zones a first zone proximal to where the mechanical force is first generated, represented in this example as F t , a second zone, represented in this example as F 2 , through which the force is transmitted through the fluid (as shown by arrows) from the piston to the membrane, and a third zone where the fluid contacts the deformable membrane, shown as
  • Fig 101 is representative of lens elements in which the deforming force changes direction between the force element and the deformable member The initial force propagates from the face of 5102 to the right as presented, but must transition from a lateral to a longitudinal direction in traversing the fluid chamber between the face of the piston and the surface of deformable member 5108
  • FIG. 102 Another configuration in which the force changes direction involves use of a secondary fluid container that is used to add fluid to, or draw fluid from, the primary fluid container in order to affect the shape of the membrane
  • Fig 102 An example is shown in Fig 102, which is identical to Fig 101 but for the addition of sealing member 51 10 which incorporates a 2-way, self-sealing valve (not shown), dividing the fluid volume into primary fluid container 51 12 and secondary fluid container 51 14
  • Motion of piston 5102 causes movement of fluid between the primary and secondary containers, and the fluid is added to or withdrawn from the primary container radial to the deformable membrane
  • FIG. 103 An analogous configuration is shown in Fig 103, showing deformable membrane 5 120, primary fluid container 5124, and secondary fluid container 5126, which interfaces with primary fluid container 5124 through interface 5122 containing a sealable 2-way valve (not shown)
  • a motive force such as a piston, acts to push fluid from secondary container 5126 into primary container 5124, and/or to pull fluid from primary container 5124 into secondary container 5126, thereby deforming the deformable membrane
  • the force deforming the membrane has an initial component within secondary container 5126 and within primary container 5124 adjacent interface 5122 that is lateral or transverse to the deformable membrane, with the force then being translated into a direction longitudinal to the deformable membrane as it travels or is propagated through primary container 5124 from the interface to the membrane
  • the force deforming the membrane may be primarily or entirely longitudinal to the membrane as it propagates from the initial point of generation to the membrane
  • this may be visualized by taking the horizontal (as shown) portion of the lens element, rotating it 90° in a counterclockwise direction, and aligning it so that at least the valve communicates directly with the primary fluid container at interface 5122
  • this must be accomplished in a manner that does not obstruct the optical axis, as by making the secondary container smaller in diameter or cross-section than the face of the primary container with which it connects, and offsetting the secondary container from the optical axis of the primary container, as seen in Fig 104
  • the path followed by the force from its inception by the force element to its absorption by the deformable membrane may be transverse to deformable membrane, longitudinal to the deformal membrane, or a combination of both
  • the terms “transverse” and “longitudinal” are used with reference to a line passing through and perpendicular to the surface of the deformable membrane when that surface is flat (or, if is never flat, perpendicular to its surface at the central point or axis), with a “transverse” force being perpendicular or substantially perpendicular to such a line, and a longitudinal force being parallel or substantially parallel to such a line
  • the terms "transverse” and “longitudinal” are used with reference to the optical axis, with a “transverse” force being perpendicular or substantially perpendicular to the optical axis, and a longitudinal force being parallel or substantially parallel to the optical axis
  • Figs 1 1 1 and 1 12 show use of a relatively narrow and relatively wide pressure element 5302, respectively, shown here in a ring or washer configuration Because the pressure element in Fig 1 12 covers more surface area of the deformable membrane than that in Fig 1 1 1 , and because the membrane is deformable, an equal amount of downward motion of the pressure elements in Figs 1 1 1 and 1 12 will result in the pressure element of Fig 1 12 producing a significantly more convex surface, as shown in Figs 1 13 and 1 14 Alternatively, if it is desired to produce the same amount of curvature or convexity with both pressure elements, then the pressure element of Fig 1 12 can be moved a smaller distance than the pressure element shown in Fig 1 1 1 to accomplish the same effect
  • Selection of heavier or lighter materials to make the ring may also affect how responsive the lens module is to input of a given amount of force, as they may respond differently to the application of force than lighter materials Similarly, the viscosity and/or specific weight of the optical fluid component may affect the responsiveness of the system to the input of a given amount of force
  • Figs 1 15 and 1 16 show convex surface 5312 of the lens element, which is convex without any force being exerted by pressure element 5316
  • pressure element 5304 moves or expands radially outward stretching the upper surface of the lens element and flattening convex surface 5312 as shown in Fig 1 16
  • pressure ring 5316 may be adhered to the surface of the deformable element, or placed inside the deformable element so that radial outward movement of the pressure element expands the diameter of the deformable member as shown
  • the pressure element could reside in a groove in the outer circumference of the upper surface of the deformable member, held in place by a rigid and at least partially electrically conductive ring or washer-shaped element surrounding the convex portion 5312, with the ring or washer-shaped element used as an electrical contact, or as a conduit for one or more electrical connections, to energize the pressure element
  • the pressure element may exert at least partially opposing forces on the deformable element This can be used, for example, to reduce the physical motion needed to produce a given change in deformation, or to increase the speed with which a given deformation can be achieved
  • Fig 1 17 A simplified version of such a configuration is shown in Fig 1 17, including lens element 5400 comprising deformable member 5402, deformable member housing element 5418, pressure element 5408, and pivot point 5410
  • the deformable member may be integral with the housing or attached to it, for example, the surface of the deformable member may be a membrane whose edge is adhered, clamped, sealed, or otherwise affixed to the housing, as by constructing the housing from upper and lower portions and sealing edge portion 5412 of membrane 5402 between upper portion 5416 and lower portion 5418 as depicted in Fig 1 18
  • one force element is so arranged that its motion will press generally downward on the deformable membrane, as suggested by upper curved arrows in Fig 1 17, imparting a general downward force to the deformable membrane as shown by the angled straight arrows
  • Another force element is configured so that its motion will cause the lower edge of the deformable membrane to move radially outward, as suggested by the lower curved arrows and straight horizontal arrows
  • These two motions will have a cumulative effect of flattening the deformable membrane more rapidly than would either force acting alone
  • This may be accomplished using a single force element, as shown, in a rocker configuration, where the force element pivots around pivot point 5410, pushing the upper arm downwardly on the deformable element while the lower arm draws the outer edge of the deformable membrane radially outward
  • the force element may be provided as two or more separately acting components, which would allow greater control over the motion If, for example, the upper and lower arms of the force element shown in Fig 1 17 were separately actuable, the lens element
  • the force element may be a unitary element extending completely around the periphery or circumference of the deformable member, or may be plural separate or discrete elements
  • Fig 1 19 is a simplified representation of one embodiment of a unitary element seen from above the lens element and looking down along the optical axis
  • 5430 is the upper surface of the deformable membrane
  • 5432 represents the physical location of an annular force element around the periphery of the deformable membrane
  • Shadowed area 5434 represents that area of the surface of the deformable membrane that is directly contacted by or receives force from the pressure element, such as through super positioning of an upper portion of the pressure element with the deformable membrane surface (not shown)
  • Fig 120 shows another embodiment, in which the force element comprises several discrete force elements 5450 around the circumference of spherical deformable member 5454, exerting force over a continuous annular area 5460 of the outer surface of the deformable member This may be accomplished by appropriately configuring the portion of each discrete
  • a unitary element may facilitate a more uniform or symmetrical response of the deformable member to force, while use of plural discrete elements may produce a more asymmetrical deformation of the deformable element, depending in part on the flexibility or stiffness of the deformable element
  • a relatively stiff deformable element will tend to transmit force applied at one point of the element more widely and uniformly to adjacent areas than will a relatively flexible deformable element
  • use of a relatively flexible deformable material to create the deformable membrane will tend to favor use of a unitary force element, such as one having a ring or washer configuration, capable of applying force uniformly around the circumference or periphery of the deformable element, whereas use of a relatively stiff deformable material to create the deformable membrane will tend to enable use of plural forced elements that, even in combined use, will exert force on discontinuous areas of the deformable membrane
  • Piezoelectric elements may be used to generate motive force for transmittal, whether hydraulically through a liquid, pneumatically through a gas, or mechanically through one or more force transmission elements such as a push ring
  • a voice coil construct may be used to generate and alter a magnetic field that will act on a magnetic component of the lens element in order to deform the deformable element
  • Fig 121 shows a lens element having fluid component 5501 in container 5502, which is in turn in housing 5503 Housing 5503 is surrounded by voice coil 5504, which acts on magnetic pressure elements 5505 to deform deformable membrane 5506
  • the pressure element is magnetic
  • a voice coil may be positioned so that when the coil is activated, the pressure element deforms the deformable element as it is drawn towards, or repelled away from, the magnetic field generated by the voice coil
  • a lens element incorporating a voice coil has several configuration parameters, for
  • an optical fluid component that is a magneto-optical fluid, that is, an optical fluid that is also magnetically responsive If the walls of container 5502 were sufficiently elastic, and/or configured for extension and compression (as by being pleated such as in an accordion shape), a voice coil and magnets could be positioned to effect extension or compression of the container in response to changes in magnetic field, with such movement of the container effecting changes in the deformable member
  • the voice coil may be, for example, a single or double voice coil It may be positioned above, at, or below the level of the deformable member, and may interact with one or more fixed magnets positioned above and/or below the level of the voice coil
  • the voice coil may be mechanically linked to the deformable member and/or the housing or container for the optical fluid, such that movement of the voice coil effects deformation of the deformable member
  • the voice coil may remain relatively fixed, and deformation of the deformable member may be accomplished by interaction of the magnetic field produced by the voice coil with a magnetic component on one more portions of the lens module, such as a magnetic pressure element or magnetic rocker arm
  • N is the refractive index of the lens material
  • R ⁇ is the radius of curvature of the lens surface closest to the light source
  • R 2 is the radius of curvature of the lens surface farthest from the light source
  • t is the center thickness of the lens (the distance along the lens axis between the two surface vertices)
  • variable lens of the present invention makes it possible to vary f, the focal length, by changing either or both of R l and R2
  • R2 becomes infinity (the radius of curvature of a plane), and hence the parameter J_
  • variable lens of the present invention it enable use if a unitary lens element, whether of the deformable solid or fluid/deformable member configuration, in which center thickness t of the lens is varied concurrently with changes in Rl and/or R2
  • Both the deformable solid lens element, and the lens element combining a fluid with a deformable member may be deformable in use on both sides or surfaces of the lens, as shown in Figs 127 and 128
  • the 'lower' surface 5602b of the deformable solid 5601 may be supported by a rigid boundary element 5603 (shown in cross-section only) having central aperture region 5604 (shown as the dotted line portion), allowing lower surface 5602b to change shape in response to force from the force element
  • the lower surface 5602b which is convex as shown, may become more convex in response to force exerted by a force element on a pressure element (not shown) contacting the periphery of upper surface 5602a and which is pressing down and/or inward on the deformable solid
  • the size and/or shape of the aperture may be such that the lower surface is substantially plan
  • the lower surface 5602b of the variable lens element in Fig 128 may be an additional deformable member rather than being a rigid boundary element, and may then function similarly to the upper deformable surface 5602a, responding to a force element that is the same as, or in addition to, the force element used to affect the shape of upper surface 5602a
  • lower deformable surface 5602b may be separately controlled by an additional force element, with separate force elements capable of acting on the upper and lower surfaces independently and in combination
  • lower deformable surface 5602b may be bounded or constrained by a rigid boundary element (not shown) that maintains lower surface 5602b in a predetermined configuration, which may be planar, convex, or concave, and which would not change in response to force provided by the force element
  • the rigid boundary element itself may be provided in any lens shape, such as convex, bi-convex, plano-convex,
  • the boundary element itself may be rigid as previously described, such as glass or plastic, or deformable, such as an elastomer
  • deformable such as an elastomer
  • glass may be used as the boundary element, and a variety of optical glass materials are commercially available, including, for example, Corning® EAGLE2000TM Display Grade glass, available from Corning Display Technologies, Corning, New York USA, and N-BK.7 glass, available from Schott North America lnc , Duryea, Pennsylvania USA
  • the boundary element may be any suitable thickness, including from about 0 1 mm to about 1 mm, for example, 0 2, 0 3, or 0 4 mm
  • a calibration process may be useful for calibrating an apparatus embodying features of the invention
  • a calibration can be initiated by initializing the system, including performing all power-on-sequence tests to assure that the system components are operating properly
  • a test target bearing a pattern or encoded symbol is positioned at a first test position When in the first test position, the target will in general be at defined distance and orientation relative to the hand held reader comprising a variable lens
  • a variable lens control signal (which in some embodiments is a voltage) is adjusted to obtain an acceptable, and preferably an optimal, focus condition for the target
  • the distance and orientation of the target and the variable lens control signal parameters are recorded for future use in a non-volatile memory, for example in a table
  • the current invention uses the principle of altering the interface shape between two fluids and provides the ability to control an optical tilt of the fluid interface to adjust an exit optical axis angle or direction relative to the variable lens
  • One application of such adjustment of the exit optical axis angle is to provide a mechanism and method to compensate for the angular movement caused by hand-jittering or hand motion
  • the present invention therefore also deals with the deleterious effects of image smear caused by hand jittering or hand motion in a hand held device, including an imager or reader Image smear has been one of the major sources for image quality degradation Image smear and similar degradation mechanisms cause a reduced decode rate in a barcode reading application or a reduced contrast and a blurry image in an image capturing application
  • hand jitter or hand motion can cause image degradation that may be severe enough to prevent the image from being processed correctly
  • variable lens provided with additional components to counteract involuntary motions
  • an anti-hand-jittering variable lens may be used to combine the auto-focusing and variable angle prism functionalities used in the prior art (such as represented in U S Patent No 6,734,903 to Takeda, et al and Japanese Patent Laid-Open No 2- 12518, into a single low cost component that has fewer moving parts and provides fast response time
  • Fig 135 is a schematic diagram 6500 showing the relationships between a variable lens and various components that allow adjustment of the optical axis direction
  • the optical axis control system comprises a horizontal angular velocity sensor 6510, a control module 6512 to generate horizontal tilt voltage dh, a vertical angular velocity sensor 6520, a control module 6522 to generate vertical tilt voltage dv, an auto- focusing control module 6530 to generate a focusing voltage Vf, a distributor module 6540 to synthesize the control voltages to control the variable lens module 6400 to accommodate or to correct for hand jittering Alternately when the axis of the optical system changes orientation, the image on the image sensor will move
  • the processor can extract the magnitude and direction of motion of the object that was not expected to move This can be used as input to the correction circuit
  • the angular velocity sensors 6510 and 6520 are commercially available low cost solid-state gy ⁇ o-on-a-ch ⁇ p products, such as GyroChips manufactured by BEI Technologies, Inc , One Post Street, Suite 2500 San Francisco, CA 94104
  • the GyroChip comprises a one piece, quartz micromachined inertial sensing element to measure angular rotational velocity
  • U S Patent No 5,396,144 describes a rotation rate sensor comprising a double ended tuning fork made from a piezoelectric material such as quartz These sensors produce a signal output proportional to the rate of rotation sensed
  • the quartz inertial sensors are micromachined using photolithographic processes, and are at the forefront of MEMS (Micro Electro- Mechanical Systems) technology These processes are similar to those used to produce millions of digital quartz wristwatches each year
  • MEMS Micro Electro- Mechanical Systems
  • Fig 136 is a schematic diagram showing the relationship between a variable lens 6700 and a pair of angular velocity sensors
  • two of the angular velocity sensors 6710, 6720 can be integrated with the variable lens 6700 to form an integrated module 6730
  • the angular velocity sensors 6710 and 6720 are arranged in an orthogonal relationship to detect two orthogonal angular velocities
  • the entire control circuitry as shown in Fig 135 can also be integrated into the module 6730
  • An advantage of this embodiment is ease of mounting the module 6730 No vertical or horizontal alignments are required The module will automatically adjust the lens tilt angle according to the output voltages dh and dv provided by the angular velocity sensors 6710 and 6720
  • apparatus and methods are provided to counteract changes in the environment that surrounds an apparatus comprising a variable lens
  • the apparatus comprises a temperature sensor with a feed back (or feed forward) control circuit, to provide correction to the variable lens operating signal as the temperature of the variable lens (or of its environment) is observed to change
  • the apparatus comprises a pressure sensor with a feed back (or feed forward) control circuit, to provide correction to the variable lens operating signal as the pressure in the ambient environment is observed to change This may, for example, facilitate operation of the variable lens under conditions of reduced pressure, such as at high altitudes (or even in vacuum), or under conditions of increased pressure, such as in pressure chambers or underwater
  • a system comprising a variable lens additionally comprises a non- variable lens component configured to correct one or more specific limitations or imperfections of the variable lens, such as correcting for color, spherical, coma, or other aberrations of the variable lens itself or of the variable lens in conjunction with one or more other optical components
  • a variable lens may exhibit dispersive behavior or color error
  • a second optical element is added that provides dispersion of the sign opposite to that exhibited by the variable lens, so as to correct the dispersive error introduced by the variable lens
  • the dispersive element is a diffraction element, such as an embossed grating or an embossed diffractive element
  • different optical materials have different dispersive characteristics, for example, two glass compositions can have different dispersion, or a composition of glass and a plastic material can have different dispersion
  • variable lenses include their use in one or more types of camera, such as cameras in cell phones, use in higher quality digital cameras such as those having a high powered zoom lens, and use in cameras that can provide auto focus, and pan, tilt, and zoom (“PTZ") Panning is moving a camera in a sweeping movement, typically horizontally from side to side Tilting is a vertical camera movement, e g in a direction orthogonal to panning
  • PTZ pan, tilt, and zoom
  • PTZ pan, tilt, and zoom
  • any given lens is optimized for a given focal length system
  • any given lens is optimized for a given focal length system
  • a lens is optimized for one combination of optical elements, it is not optimally configured when one of the lens surfaces is changed as would happen when a single fluid element is operated to change an optical parameter, such as focal length
  • the combination of the first lens and the second lens can be optimized to minimize total system aberrations
  • corresponding changes in the settings of the second lens can be made to obtain an optimal combination
  • the lens module of the present invention may be incorporated into a wide variety of devices
  • the devices may be stationary/fixed or portable, and include data collection devices such as bar code scanners and portable data terminals, portable digital assistants, portable computers, including notebooks and laptops, cordless and cellular telephones, including camera cell phones, and smart phones, the latter including hand held devices which combine wireless phone capabilities with other functions such as network connectivity (whether Internet, WLAN, WMAN, WWAN, or other), the ability to play music or video files, the ability to display images, the ability to send and/or receive e-mail, and so on These products are changing rapidly, examples of current such devices include the Palm® Treo®, the BlackBerry® smart phones (Curve, 8800, Pearl, 8700 Series, and so on), the HelioTM Ocean, Heat, and Drift devices, and the Apple® iPhoneTM
  • a small sample of systems methods and apparatus that are described herein is as follows A l An apparatus for use in a lens assembly, said apparatus comprising
  • a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting at least one of a pushing force or a pulling force to said deformable surface
  • A2 The apparatus of claim A l , wherein said force imparting structural member is adapted to impart a force to said deformable surface at a plurality of force impartation points formed in a ring pattern spaced apart from and peripherally disposed about said axis
  • A3 The apparatus of claim A l , wherein said force imparting structural member is adapted to impart a force to said deformable surface at a plurality of force impartation points formed in an area pattern about said axis
  • A5 The apparatus of claim A l , wherein said force imparting structural member is a structural member that transmits force generated by an actuator
  • A6 The apparatus of claim A l , wherein said force imparting structural member imparts a force generally in a direction of said axis
  • A8 The apparatus of claim A l , wherein a major body of said deformable lens element comprises a resiliently deformable material member, and wherein said deformable lens element is devoid of a focus fluid
  • a l O The apparatus of claim A l , wherein said apparatus is adapted so that said structural member is capable of imparting a pulling force to said deformable surface
  • B l An apparatus for use in a lens assembly, said apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting a pushing force to said deformable surface resulting in a thickness of said deformable lens member along a plurality of imaginary lines running in parallel with said imaging axis decreasing B2
  • said apparatus is adapted so that when said pushing force is imparted to said deformable surface, said deformable surface bulges outward in an area of said deformable surface about said axis
  • An apparatus for use in a lens assembly comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting one or more of the following to said deformable surface
  • Dl An apparatus for use in a lens assembly, said apparatus comprising a deformable lens member having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting a pushing force to said deformable surface resulting in a thickness of said deformable lens member along said axis decreasing
  • E l A method comprising incorporating a deformable lens element into an optical system, said deformable lens element having a deformable surface, at least part of which transmits image forming light rays, and imparting a force to said deformable surface of said deformable lens element at a plurality of force impartation points of said surface to vary an optical characteristic of said optical system, wherein said imparting step includes the step of utilizing a force imparting structural member for imparting said force
  • Fl A method comprising incorporating a deformable lens element having an axis into an optical system, said deformable lens element having a deformable lens surface at least a part of which transmits image forming light rays, and imparting a pulling force to said deformable surface of said deformable lens element to vary an optical characteristic of said optical system, wherein said imparting step includes the step of imparting said pulling force generally in a direction of said axis
  • said imparting step includes the step of imparting said pulling force at a plurality of points spaced apart from and peripherally disposed about said axis
  • G l An optical imaging system comprising a deformable lens element having a deformable surface at least part of which transmits image forming light rays, a force imparting structural member opposing said surface, and wherein said imaging system is adapted so that a force can be imparted by said force imparting structural member at a plurality of force impartation points of said deformable surface of said deformable lens element for varying an optical characteristic of said imaging system G2
  • the optical imaging system of claim G l wherein said force impartation points are defined in an area pattern about an axis of said deformable lens element
  • An optical imaging system comprising a deformable lens element comprising a deformable membrane, a cavity delimited by said deformable membrane, and fluid disposed in said cavity, said fluid having an index of refraction greater than one, said deformable lens element having an axis, and a force imparting structural member capable of contact with said deformable lens element at positions defined circumferentially about said axis, wherein said optical imaging system is configured so that said force imparting structural member can be moved generally in a direction of said axis either toward or away from said deformable lens element so that an optical characteristic of said imaging system vanes with movement of said force imparting structural member
  • An optical imaging system comprising a deformable lens element comprising a deformable membrane, a cavity delimited by said deformable membrane, and fluid disposed in said cavity, said fluid having an index of refraction greater than one, said deformable lens element having an axis, a ring-shaped pressure element in contact with said deformable lens element and arranged circumferentially about said axis, and an electro-active polymer actuator mechanically coupled to said ring-shaped pressure element, said optical imaging system being configured so that said electro-active polymer actuator moves said ring-shaped pressure element generally in a direction of said axis so that an optical characteristic of said imaging system varies with movement of said ring-shaped pressure element
  • said electro-active polymer actuator includes a ring- shaped deformable element comprising a plurality of tab-like elements, said deformable element being circumferentially disposed about said axis, said plurality of tab-like elements engaging said ring shaped pressure element J l
  • An optical imaging system comprising a deformable lens element having an axis, wherein a major body of said deformable lens element is provided by a resiliently deformable member having a hardness measurement of less than Shore A 60, and wherein said imaging system is configured so that a force can be applied to an external surface of said deformable lens for varying an optical characteristic of said imaging system
  • optical imaging system includes an flexible member actuator for imparting said force, said actuator having a flexible member adapted to substantially conform to a shape of said deformable lens element
  • K l An optical system for use in imaging an object, said system comprising a deformable lens element capable of being deformed wherein said deformable lens element has a deformable surface that faces an exterior of said deformable lens element, said deformable lens element having an axis, wherein said optical system is adapted so that said system can impart a force to said deformable surface generally in a direction of said axis toward said deformable lens element in such manner that an optical property of said deformable lens element is changed by impartation of said force
  • An optical system for use in imaging an object comprising a deformable lens element having a deformable lens surface, at least part of which transmits image forming light rays and which faces an exterior of said deformable lens element, said deformable lens surface being one of normally convex or capable of exhibiting a convex curvature, said deformable lens element having an axis, and an actuator for imparting a force to said deformable surface, the actuator having an aperture disposed about said axis, the optical system being adapted so that actuation of said actuator results in a force being imparted to said deformable surface to vary a convexity of said deformable lens element
  • optical system of claim L l wherein said optical system includes a pressure element transferring a force generated by said actuator to said deformable lens element
  • a hand held data collection terminal comprising a two dimensional image sensor comprising a plurality of pixels formed in a plurality of rows and columns of pixels, an imaging lens assembly comprising a deformable lens element for focusing an image onto said two dimensional image sensor, said imaging lens being adapted so that said deformable lens element can be deformed with use of a force imparting structural member, said imaging lens assembly being adapted so that force can be applied to an external surface of said deformable lens element to vary an optical property of said deformable lens element, said imaging lens setting having a first lens setting at which said deformable lens element is in a first state and a second lens setting at which said deformable lens element is in a second state, and a trigger for activating a trigger signal, said data collection terminal being adapted so that said trigger signal can be maintained in an active state by maintaining said trigger in a depressed position, wherein said data collection terminal is adapted so that responsively to said trigger signal being maintained in said active state, said data collection terminal captures in succession a plurality of
  • a focus apparatus comprising a deformable lens element having an axis, wherein a major body of said deformable lens element comprises a resiliency deformable member having at least one normally convex lens surface, and an actuator for deforming said deformable lens element, the actuator having a flexible member adapted to substantially conform to a shape of said convex lens surface and having one of a coated area or an aperture disposed about said axis, the focus apparatus being adapted so that by varying a voltage applied to said flexible member a convexity of said normally convex lens surface changes
  • N6 The focus apparatus of claim N l , wherein said flexible member is a flexible member interposed between a pair of flexible electrodes
  • a focus apparatus comprising a deformable lens element having an axis, wherein a major body of said deformable lens element comprises a resiliently deformable member having at least one convex lens surface, and an actuator for imparting a force to said deformable lens element to deform said deformable lens element and to change an optical property of said deformable lens element
  • said actuator has an aperture disposed about said axis, said actuator being selected from the group consisting of an ion conductive electro-active polymer actuator, a dielectric electro-active polymer actuator, and a hollow stepper motor
  • said deformable lens element has a deformable surface, at least part of which transmits image forming light rays, and where said focus apparatus includes a force imparting structural element imparting a force generated by said actuator to said deformable surface
  • a focus apparatus for use in an optical imaging system, said focus apparatus comprising, a deformable lens element having a deformable light entry surface and an opposing deformable light exit surface, the deformable lens element having an axis intersecting respective centers of said deformable light entry surface and said opposing deformable light exit surface, a first actuator for deforming said deformable light entry surface to change an optical property of said deformable lens element, and a second actuator for deforming said deformable light exit surface to change an optical property of said deformable lens element
  • said focus apparatus includes a first deformable membrane defining said light entry surface and second deformable membrane defining said second light entry surface, a window, first cavity delimited by said first deformable membrane and said window, a second cavity delimited by said second deformable membrane and said window, and focus fluid disposed in each of said first and second cavities
  • a deformable lens element comprising a first clamping element, the first clamping element including a rigid transparent member having an optical surface for allowing light rays to pass there through, a deformable membrane, a second clamping member clamping said deformable membrane against said first clamping element so that said deformable membrane opposes said rigid transparent optical surface, a cavity delimited by said deformable membrane and said first clamping element, and a deformable substance having an index of refraction greater than one disposed in said cavity
  • a focus module comprising a boundary element, a focus membrane, a focus fluid entrapped between said boundary element and said focus membrane, and a deforming element contacting said focus membrane
  • a focus module comprising a boundary element, a spacer element, a focus membrane, a focus fluid entrapped between said boundary element and said focus membrane, and a deforming element contacting said focus membrane
  • U 1 A focus module comprising a cylinder having (i) a top surface, (11) a bottom surface, (in) an outer wall, and (iv) a fluid interior volume therewithin, and a deforming element external to said cylinder, said deforming element being capable of exerting pressure on said top surface, thereby deforming said top surface
  • V l A focus module, comprising, in order a boundary element, a focus element, and a deforming element
  • V4 The focus module of claim V3, wherein said at least one intermediary element comprises a pressure element
  • V5 The focus module of claim V4, wherein said deforming element presses on said pressure element and said pressure element is in contact with said focus element, thereby transmitting force to said focus element
  • a lens module comprising a lens element, said lens element comprising i a working fluid component comprising a substantially optically clear fluid, and it an optical non-fluid component, comprising an elastically deformable member having first and second surfaces and being substantially optically clear over at least a portion thereof, only one of said surfaces facing towards said working fluid component, and in an optical axis passing through said working fluid component and said optical non-fluid component, a force element capable of providing an applied force sufficient to deform said elastically deformable member, and operably connected to said elastically deformable member such that force provided by said force element will be at least partially transmitted to said elastically deformable member, wherein the force provided by said force element passes in order from said force element, to the surface of said elastically deformable member facing away from said working fluid component, to said working fluid component
  • a lens module comprising a lens element, said lens element comprising i working fluid component comprising a substantially optically clear fluid, Ii an optical non-fluid component, comprising an elastically deformable member and being substantially optically clear over at least a portion thereof, and in an optical axis passing through said working fluid component and said optical non-fluid component, a force element capable of providing an applied force sufficient to deform said elastically deformable member, and operably connected to said elastically deformable member such that force provided by said force element will be at least partially transmitted to said elastically deformable member, said force element being disposed in a circumferentially symmetric relationship to said elastically deformable member Yl
  • a focus module for use in a data collection device capable of at least one of reading 1 D bar codes, reading 2D bar codes, and taking images, said focus module comprising a boundary element, a focus element deformable in at least one dimension, a spacer element interposed between said boundary element and said focus element, an actuator element for transmitting force to

Abstract

An apparatus for use in a lens assembly, the apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming ligth rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein the apparatus is adapted so that said force imparting structural member is capable of imparting at least one of a pushing force or a pulling force to the deformable surface.

Description

APPARATUS AND METHOD COMPRISING DEFORMABLE LENS ELEMENT CROSS REFERENCE TO RELATED APPLICATIONS
[0001 ] This PCT application claims priority to U S Patent Application No 60/875,245, entitled "Focus
Module and Components With Actuator Polymer Control," filed December 15, 2006, to U S Patent Application No 60/961 ,036 entitled "Variable Lens Elements And Modules," filed July 18, 2007, to U S Patent Application No 1 1/781 ,901 , entitled "Focus Module And Components With Actuator Polymer Control," filed July 23, 2007 which claims priority to said U S Patent Application No 60/875,245, and to 1 1/897,924 filed August 3 1 , 2007, entitled "Apparatus and Method Comprising Deformable Lens Element" which claims priority to said U S Patent Application No 60/875,245 and U S Patent Application No 60/961 ,036 All of the above patent applications are incorporated herein by reference in their entirety
FIELD OF THE INVENTION
[0002] The invention relates to a lens element for incorporation into an optical imaging system and specifically to an apparatus and method comprising a deformable lens element
BACKGROUND OF THE INVENTION
[0003] Variable lenses, e g , multiple focus lenses and ?oom lenses have traditionally employed one or more non-deformable (; e , rigid such as glass or polycarbonate) lens elements which are moved along an imaging axis by forces often supplied by a motor
[0004] In recent years, motorless electro-responsive lens elements have attracted increased attention of researchers and designers of optical systems One type of motorless electro-responsive lens element is the "fluid lens" lens element which generally includes a rigid or elastomeric membrane filled with one or more fluids having indices of refraction greater than 1 Fluid lens element technology has attracted the attention of many designers of optical systems who generally see traditional solid lens elements and motor equipped systems as bulky and energy hungry With the proposals for fluid lens elements there have been proposed various methods for varying an optical property of a fluid lens element for integration into an optical system Where fluid lens elements have been proposed, the proposed alternatives for varying optical properties of such lens elements can be categorized into two broad categories electro wetting and fluid injection
[0005] According to a process of electro wetting, a fluid lens element is provided having at least two immiscible fluids and a voltage is applied to the fluid lens element A surface tension of the fluid lens element changes as a result of the voltage being applied, bringing about a change in the curvature of an interface between the at least two fluids
[0006] According to a process of fluid injection, a pump is provided adjacent a fluid lens element which pumps in and draws out fluid from the lens element As fluid is pumped in and drawn out of the lens element, optical properties of the lens element change [0007] Problems have been noted with both the electro wetting and fluid injection methods for varying an optical property of a fluid lens element Regarding electro wetting, one problem that has been noted is that the electrical current repeatedly flowing through the lens element tends to alter the characteristics of the lens element over time, rendering any system in which the lens element is employed unreliable and unpredictable Another problem noted with proposals involving electro wetting is that electro wetting normally involves providing two types of fluids As the reference index difference between the fluids is small, the power of the lens element is reduced
[0008] Regarding the fluid injection methods, the pumps for providing such fluid injection are necessarily complex and intricate making a reasonably costly system and acceptable miniaturization difficult to achieve
[0009] Because of the problems noted with both the electro wetting and fluid injection methods for varying an optical property of a deformable lens element, designers of commercially deployed optical systems continue to rely almost exclusively on traditional motor-actuated rigid lens elements in the design of optical systems Yet, the miniaturization and energy conservation achievable with motor-actuated rigid element equipped optical systems continues to be limited
[0010] In brief, a fluid lens, sometimes also referred to as an adaptive lens, comprises an interface between two fluids having dissimilar optical indices The shape of the interface can be changed by the application of external forces so that light passing across the interface can be directed to propagate in desired directions As a result, the optical characteristics of a fluid lens, such as whether the lens operates as a diverging lens or as a converging lens, and its focal length, can be changed in response to the applied forces
[001 1 ] Fluid lens technology that employs electrical signals to control the operation of the fluid lens has been described variously in Matz, U S Patent No 2,062,468, Berge et al , U S Patent No 6,369,954, Onuki et al , U S Patent No 6,449,081 , Tsuboi et al , U S Patent No 6,702,483, Onuki et al , U S Patent No 6,806,988, Nagaoka et al , U S Patent Application Publication No 2004/0218283, Takeyama et al , U S Patent Application Publication No 2004/0228003, and Berge, U S Patent Application Publication No 2005/00021 13, as well as International Patent Application Publications Nos WO 99/ 18546, WO 00/58763, and WO 03/069380
[0012] Additional methods of controlling the operation of fluid lenses include the use of liquid crystal material (Nishioka, U S Patent No 6,437,925), the application of pressure (Widl, U S Patent No 6,081 ,388), the use of elastomeπc materials in reconfigurable lenses (Rogers, U S Patent No 4,514,048), and the uses of micro-electromechanical systems (also known by the acronym "MEMS") (Gelbart, U S Patent No 6,747,806)
[0013] Further attempts to develop fluid lens control modules may be see in, for example, Sasaya et al ,
U S Patent No 6, 188,526, de Luca, U S Patent No 3, 161 ,718, Flint, U S Patent No 2,300,251 , Yao et al , U S Patent Application Publication No 2005/0014306, O'Connor et al , U S Patent Application Publication No 2005/0100270, Massieu, U S Patent Application Publication No 2005/0218231 , Michelet, U S Patent No 4,289,379, Vnnikanoja, U S Patent No 6,936,809, European Patent Application EP I 674 892 A l , British Patent Specification GB 1327503, Japanese Patent No JP2002243918 (Olympus Optical, Application No JP20010037454), and International Patent Application Publication No WO 03/071335 [0014] Further examples include Shahinpoor, U S Patent 5,389,222, Shahinpoor et al , U S Patent
6, 109,852, Guy, U S Patent 6,542,309, Pelπne et al , U S Patent 6,376,971 , Ren H , Fox D , Anderson A , Wu B , and Wu S-T, 2006, "Tunable-focus liquid lens controlled using a servo motor", Optics Express 14( 18) 8031 - 8036, Santiago-Alvarado A1, Gonzalez-Garcia J, Garcia-Luna J, Fernandez-Moreno A, and Vera-Diaz W, 2006, "Analysis and design of an adaptive lens", Proceedings of SPIE Optics and Photonics 6288 62880S- 1 - 62880S- 8, Ghosh TK, Kotek R, and Muth J, 2005, "Development of layered functional fiber based micro-tubes", National Textile Center Annual Report 1 -9, Pelπne R, Kornbluh RD, Pei Q, Stanford S, Oh S, Eckerle, J, Full RJ, Rosenthal MA, and Meijer K, 2002, "Dielectric elastomer artificial muscle actuators toward biomimetic motion", Proc SPIE 4695 126- 137, Chronis N, Liu GL, Jeong K-H, and Lee LP, 2003, "Tunable liquid-filled microlens array integrated with microfluidic network", Optics Express 1 1 ( 19) 2370-2378, each of which is incorporated herein by reference in its entirety
[0015] However, there is a continuing need for improved systems and methods for using fluid lenses in present day systems
[0016] Lenses and lens systems may be fixed or variable, and a lens system may contain fixed and/or variable lenses A fixed lens system, and a fixed lens, have a fixed or static focal point, that is, the focal length and orientation of the optical axis do not change For example, a non-deformable, solid lens rigidly attached to an optical system would, in and of itself, be fixed, and if the lens system did not contain any other elements capable of changing the focal length and/or orientation of the optical axis of the lens system, the lens system would similarly be fixed
[0017] A conventional pair of eyeglasses is such a fixed lens system Each lens in the eyeglasses is a fixed lens because it is incapable of changing its focal length or the orientation of its optical axis Because the eyeglasses do not contain any additional lenses or other methods to effect such a change, the eyeglasses themselves are a fixed lens system
[0018] This may be contrasted with a simple telescope containing two glass lenses, each rigidly attached to a different and concentric portion of the telescope housing, where the lenses can be moved towards and away form each other by sliding the concentric portions of the housing relative to each other Each individual lens is fixed it they cannot, in and of itself, change focal length or orientation of the optical axis However, the telescope overall is a variable lens system, because sliding the concentric portions of the housing relative to each other changes the focal length by changing the distance between the two fixed lenses
[0019] A variable lens, in contrast, is inherently variable, and any lens system incorporating it is likewise inherently variable Fixed lenses are generally composed of non-deformable materials such as glass or plastic, or, if composed of an elastic or deformable material, are part of a lens system that does not include any method for causing them to stretch, compress, bend, or otherwise change shape or deform A variable lens may be composed of elastic or deformable materials, and, where it is desired that the lens be capable of returning to its original state after being stretched, compressed, bent, or otherwise deformed, will be composed of one or more elastically deformable elements [0020] A number of types of force elements may be used to provide the force required to change the shape of the interface in a variable lens Fluid lenses using technology that employs electrical signals to control the operation of the fluid lens have been described in Matz, U S Patent No 2,062,468, Berge et al , U S Patent No 6,369,954, Onuki et al , U S Patent No 6,449,081 , Tsuboi et al , U S Patent No 6,702,483, Onuki et al , U S Patent No 6,806,988, Nagaoka et al , U S Patent Application Publication No 2004/0218283, Takeyama et al , U S Patent Application Publication No 2004/0228003, Berge, U S Patent Application Publication No 2005/00021 13, International Patent Application Publications Nos WO 99/18546, WO 00/58763, and WO 03/069380, and Havens et al , U S Patent Application Publication No 20070063048 For example, a fluid lens may be constructed using a first insulating fluid and a second conductor fluid that are in contact at a contact region and are situated within a dielectric chamber A first electrode is placed on the external surface of the wall of the dielectric chamber, on which is situated the insulating fluid A second electrode contacts the conductor fluid When a voltage is established between the first and second electrodes, an electrical field is created which, according to the electro-wetting principle, changes the wetting properties of the conductive fluid on a surface of the container relative to the nonconductive fluid, so that the conductor fluid moves and deforms the insulating fluid Because the shape of the interface between the two fluids is changed, a variation of the focal length, point of focus of the lens, or orientation of the optical axis is obtained
[0021 ] Micropump control systems may also be used to control fluid lenses, as described for example in
Havens et al , U S Patent Application Publication No 20070080280 Such systems may involve a chamber or container of fluid in force communication with a deformable membrane There may be a single such chamber, which contains or is acted on by a mechanical force element, such as a piston, to push fluid towards, or draw it away from, the membrane Alternatively, there may be one or more secondary chambers, which may be used to add fluid to, or withdraw fluid from, a primary chamber that is in force communication with the membrane, and a mechanical force element may be used to effect the movement of fluid between the primary and secondary chambers In these systems, while the mechanical force element may be powered by electricity, the force actually acting on the interface in order to change its shape is mechanical
[0022] Additional methods of controlling the operation of fluid lenses include the use of liquid crystal material (Nishioka, U S Patent No 6,437,925), the application of pressure (Widl, U S Patent No 6,081 ,388), the use of elastomeric materials in reconfigurable lenses (Rogers, U S Patent No 4,514,048), and the uses of micro-electromechanical systems (also known by the acronym "MEMS") (Gelbart, U S Patent No 6,747,806)
[0023] Further attempts to develop fluid lens control modules may be see in, for example, Sasaya et al ,
U S Patent No 6, 188,526, de Luca, U S Patent No 3, 161 ,718, Flint, U S Patent No 2,300,251 , Yao et al , U S Patent Application Publication No 2005/0014306, O'Connor et al , U S Patent Application Publication No 2005/0100270, Massieu, U S Patent Application Publication No 2005/0218231 , Michelet, U S Patent No 4,289,379, Vnnikanoja, U S Patent No 6,936,809, European Patent Application EP 1 674 892 A l , British Patent Specification GB 1327503, Japanese Patent No JP2002243918 (Olympus Optical, Application No JP20010037454), and International Patent Application Publication No WO 03/071335 [0024] Further examples include Shahinpoor, U S Patent 5,389,222, Shahinpoor et al , U S Patent
6, 109,852, Guy, U S Patent 6,542,309, Pelrine et al , U S Patent 6,376,971 , Flint, U S Patent 2,300,251 , DeLuca, U S Patent No 3, 161 ,718, Alvarez, U S Patent No 3,305,294 issued February 21 , 1967 to Alvarez, Baker, U S Patent No 3,583,790, Ren H , Fox D , Anderson A , Wu B , and Wu S-T, 2006, "Tunable-focus liquid lens controlled using a servo motor", Optics Express 14( 18) 8031 -8036, Santiago-Alvarado A,, Gonzalez- Garcia J, Garcia-Luna J, Fernandez- Moreno A, and Vera-Diaz W, 2006, "Analysis and design of an adaptive lens", Proceedings of SPIE Optics and Photonics 6288 62880S- I - 62880S-8, Ghosh TK, Kotek R, and Muth J, 2005, "Development of layered functional fiber based micro-tubes", National Textile Center Annual Report 1 -9, Pelπne R, Kombluh RD, Pel Q, Stanford S, Oh S, Eckerle, J, Full RJ, Rosenthal MA, and Meijer K, 2002, "Dielectric elastomer artificial muscle actuators toward biomimetic motion", Proc SPIE 4695 126- 137, and Chronis N, Liu GL, Jeong K-H, and Lee LP, 2003, "Tunable liquid- filled microlens array integrated with microfluidic network", Optics Express 1 1 ( 19) 2370-2378
[0025] All of the above references are incorporated herein by reference in their entireties
SUMMARY OF THE INVENTION
[0026] An apparatus comprising a deformable lens element can be provided wherein a deformable lens element can be deformed to change an optical property thereof by the impartation of a force to the deformable lens element
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] The features described herein can be better understood with reference to the drawings described below The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention In the drawings, like numerals are used to indicate like parts throughout the various views
[0028] Fig 1 is an exploded assembly view of a focus apparatus (focusing module) including a deformable lens element that is arranged in such manner that the deformable lens element can be deformed to vary an optical characteristic of the lens element
[0029] Fig 2 is an assembled view of the focus apparatus of Fig 1 , showing the apparatus in a state in which the deformable lens element includes a convex lens surface
[0030] Fig 3 is an assembled view of the focus apparatus of Fig 1 showing the apparatus in a state in which the deformable lens element includes a nominally planar surface
[0031 ] Fig 4 is a cutaway side view showing an alternative embodiment of the deformable lens element -3
[0032] Fig 5 is a cutaway side view showing an alternative embodiment of the deformable lens element of Figs 1 -3 [0033] Fig 6 is an exploded perspective assembly view of a focus apparatus incorporating a dielectric electro-active polymer actuator
[0034] Fig 7 is an exploded perspective view of a focus apparatus incorporating a deformable lens element and a hollow stepper motor
[0035] Fig 8 is a cutaway side view of the focusing apparatus as shown in Fig 7
[0036] Fig 9 is a perspective view illustrating operation of a hollow stepper motor in one embodiment
[0037] Fig 10 is an exploded perspective assembly view of a deformable lens element in one embodiment
[0038] Fig 1 1 is an assembled cutaway side view illustrating the deformable lens element shown in Fig
10
[0039] Fig 12 is a detailed cutaway side view illustrating a highlighted section of the deformable lens element as shown in Fig 10
[0040] Fig 13 is an assembled side view illustrating a deformable lens element having a pair of opposing light entry and light exit lens surfaces that comprise respective deformable membranes
[0041 ] Fig 14 is an assembled side view showing an embodiment of a focusing apparatus incorporating a deformable lens element as shown in Fig 13, a first actuator for deforming a first deformable lens surface of the deformable lens element and a second actuator for deforming a second deformable lens surface of the deformable lens element
[0042] Fig 15 is an assembled side view of a deformable lens element incorporating a resiliently deformable material member
[0043] Fig 16 is an assembled side view of another embodiment of a deformable lens element incorporating a resiliently deformable material member
[0044] Fig 17 is a side view of a deformable lens element including a resiliently deformable material member and a protective coating thereon
[0045] Fig 18 is an assembled side view of a focus apparatus having a deformable lens element and a pair of flexible member actuators, wherein the flexible members are adapted to substantially conform to the shape of the deformable lens element
[0046] Fig 19 is an exploded perspective assembly view of a focus apparatus as shown in Fig 18
[0047] Fig 20 and Fig 21 are force impartation diagrams illustrating exemplary force impartation positions for a deformable lens member, showing front views of a deformable lens element looking in the direction of an imaging axis [0048] Figs 22-24 are side schematic views illustrating various lens assemblies incorporating at least one deformable lens element
[0049] Fig 25 is an electrical block diagram of an exemplary imaging terminal in which a deformable lens element can be incorporated
[0050] Fig 26 is a timing diagram for illustrating exemplary aspects of operation of an imaging terminal in one embodiment
[0051 ] Fig 27 is a flow diagram illustrating an auto-focus algorithm that can be executed by an imaging terminal in one embodiment
[0052] Fig 28 is a front perspective view of a hand held mobile terminal having a hand held housing in which the components as shown in Fig 25 can be incorporated and supported by
[0053] [The following is text substantially as presented in U S Patent Application No 1 1/781 ,901 which includes text substantially as presented in U S Patent Application No 60/875,245]
[0054] Fig 29 is an exploded view of one embodiment of a focus module
[0055] Fig 30 is the focus module of Fig 29 as viewed from the right side
[0056] Fig 31 is the focus module of Fig 29 as viewed from the left side
[0057] Figs 32 and 33 show the effect of pressure exerted on the focus membrane in a direction substantially normal to the plane of the focus membrane
[0058] Figs 34 and 35 show the effect of pressure exerted on the focus membrane in a direction substantially parallel to the plane of the focus membrane
[0059] Fig 36 is a view of the deforming element
[0060] Fig 37 shows the focus fluid having a non-symmetric meniscus
[0061 ] Fig 38 shows a cylindrical component of the focus module
[0062] Figs 39 is a side perspective showing convex distortion of the top surface of a cylinder having a fluid interior volume in response to a reduction in height of the cylinder
[0063] Fig 40 is a side perspective showing convex distortion of the top surface of a cylinder having a fluid interior volume in response to a reduction in diameter of the cylinder
[0064] Figs 41 and 42 illustrate the deforming element as it deforms from the initial shape shown in Fig
41 to that in Fig 42 by vertical contraction/horizontal elongation [0065] Fig 43 shows the deforming element assuming a funnel-like shape
[0066] Figs 44-47 show various ranges or directions of motion for the deforming element
[0067] Figs 48 and 49 show a bi-convex electro-actuated polymer membrane lens
[0068] Fig 50 shows a lens assembly incorporating multiple deformable focus membranes
[0069] Figs 51 and 52 show a conventional lens with an electro-actuated polymer deforming element
[0070] Fig 53 is a diagram showing a reader
[0071 ] Fig 54 is a diagram showing the control circuitry of the reader of Fig 53 in greater detail
[0072] Fig 55 is a block diagram of an optical reader showing a general purpose microprocessor system that is useful with various embodiments of the invention
[0073] Fig 56 is a flow chart showing a process for operating a system having an adjustable focus system comprising feedback
[0074] Fig 57 is a flow chart showing a process for operating a system having an adjustable focus system that does not comprise feedback
[0075] Fig 58 is a circuit diagram showing a commutating power supply for a fluid lens system
[0076] Fig 59 is a timing diagram showing a mode of operation of the commutating power supply of Fig
58
[0077] Figs 60 and 61 are drawings of hand held readers
[0078] Fig 62 is a diagram of a handheld reader in communication with a computer
[0079] Fig 63 is a flow chart of a calibration process useful for calibrating apparatus embodying features of the invention
[0080] Fig 64 is a diagram showing calibration curves for a plurality of hand held readers
[0081 ] Fig 65 is a diagram showing an embodiment of a power supply suitable for use with hand held readers,
[0082] Fig 66 is a timing diagram illustrating a mode of operation of a hand held reader
[0083] Figs 67-69 are cross-sectional drawings showing a fluid lens with a mount comprising an elastomer for a hand held reader
[0084] Fig 70 is a diagram illustrating a prior art variable angle prism [0085] Fig 71 is a cross-sectional diagram of a prior art fluid lens that is described as operating using an electro-wetting phenomenon
[0086] Fig 72 is a cross sectional diagram 2400 showing an embodiment of a fluid lens configured to allow adjustment of an optical axis
[0087] Fig 73 is a plan schematic view of the same fluid lens
[0088] Fig 74 is a schematic diagram showing the relationships between a fluid lens and various components that allow adjustment of the optical axis direction
[0089] Fig 75 is a schematic diagram of an alternative embodiment of a fluid lens
[0090] Fig 76 is a schematic diagram of an alternative embodiment of a distributor module
[0091 ] Fig 77 is a schematic diagram showing the relationship between a fluid lens and a pair of angular velocity sensors
[0092] Figs 78-82 are cross-sectional diagrams of another prior art fluid lens that can be adapted for use according to the principles of the invention
[0093] Fig 83 is a schematic block diagram showing an exemplary driver circuit
[0094] Figs 84 and 85 are diagrams that show an LED die emitting energy in a forward direction through a fluid lens
[0095] Figs 86, 87 and 88 show diagrams of a laser scanner comprising a laser 31 10, a collimating lens
3120, and a fluid lens 3130 in various configurations
[0096] [End of text substantially as presented in U S Patent Application No 1 1/781 ,901]
[0097] Fig 89 is a schematic diagram of an apparatus having a membrane
[0098] Fig 90 is a schematic diagram of the apparatus of Fig 89 after assuming a convex shape
[0099] Fig 91 is a schematic diagram of an apparatus having a container and a fluid component
[00100] Fig 92 is a schematic diagram of the apparatus of Fig 91 in an alternative state
[00101 ] Figs 93-96 are schematic views of a deformable member illustrating locations of force elements in alternative embodiments
[00102] Fig 97 is a schematic diagram of an apparatus having a pressure element
[00103] Fig 98 is a schematic diagram of the apparatus of Fig 97 in an alternative state [00104] Fig 99 is a schematic diagram showing an alternative embodiment of an apparatus having a pressure element
[00105] Fig 100 is a schematic diagram showing an alternative embodiment of an apparatus having a pressure element
[00106] Fig 101 is a schematic diagram of an apparatus having a piston
[00107] Fig 102 is a schematic diagram of an apparatus having a piston in an alternative embodiment
[00108] Fig 103 is a schematic diagram having a primary fluid container and a secondary fluid container
[00109] Fig 104 is a schematic diagram of an apparatus having a secondary fluid container in another embodiment
[001 10] Fig 105 is a schematic diagram for illustrating directions of forces that can be applied to an apparatus
[001 1 1 ] Fig 106 is a schematic diagram illustrating a shape of a pressure element
[001 12] Figs 107- 1 10 are schematic diagrams illustrating alternative shapes for a pressure element
[001 13] Fig 1 1 1 is a schematic diagram showing an apparatus having a pressure element
[001 14] Fig 1 12 is a schematic diagram shown an apparatus having a pressure element in an alternative embodiment
[001 15] Fig 1 13 is a schematic diagram illustrating the apparatus of Fig 1 10 in an alternative state
[001 16] Fig 1 14 is a schematic diagram illustrating the apparatus of Fig 1 13 in an alternative state
[001 17] Fig 1 15 is a schematic diagram of an apparatus having a pressure element that applies a force in a radial outward direction
[001 18] Fig 1 16 is a schematic diagram of the apparatus of Fig 1 15 in an alternative state
[001 19] Fig 1 17 is a schematic diagram of an apparatus having a pressure element that can apply particularly opposing forces
[00120] Fig 1 18 is a schematic diagram of an apparatus having a deformable member
[00121 ] Fig 1 19 is a schematic diagram of an apparatus having an alternative fluid element
[00122] Fig 120 is a schematic diagram of an apparatus having a plurality of discrete force elements
[00123] Fig 121 is a schematic diagram of an apparatus having a voice coil in one embodiment [00124] Fig 122 is a schematic diagram of an apparatus having a voice coil in another embodiment
[00125] Fig 123 is a schematic diagram of an apparatus having a voice coil in another embodiment
[00126] Fig 124 is a schematic diagram of an apparatus having a voice coil in another embodiment
[00127] Fig 125 is a schematic diagram of the apparatus of Fig 124 in a first state
[00128] Fig 126 is a schematic diagram of the apparatus of Fig 124 in a second state
[00129] Fig 127 is a schematic diagram of an apparatus having a plurality of deformable surfaces in one embodiment
[00130] Fig 128 is a schematic diagram of an apparatus having a plurality of deformable surfaces in another embodiment
[00131 ] Fig 129 is a schematic diagram of an apparatus having a boundary element
[00132] Fig 130.is a schematic diagram of an apparatus having a boundary element in another element
[00133] Fig 131 is a schematic diagram of an apparatus having a convex surface
[00134] Fig 132 is a schematic diagram of an apparatus having a housing
[00135] Figs 133 and 134 are drawings of hand held readers that embody features of the invention
[00136] Fig 135 is a schematic diagram showing the relationship between a variable lens and various components that allow adjustment of the optical axis direction, all according to principles of the invention
[00137] Fig 136 is a schematic diagram showing the relationship between a variable lens and a pair of angular velocity sensors, according to principles of the invention
DETAILED DESCRIPTION OF THE INVENTION
[00138] There is described herein in one embodiment a deformable lens element for incorporation into an optical imaging system, wherein a force can be imparted to a surface of the deformable lens element for varying of an optical property of the lens element There is accordingly, also described herein a method for varying an optical property of an optical imaging system including the steps of incorporating a deformable lens element into an optical imaging system, and imparting a force to a surface of the lens element for varying an optical property of the lens element With the described apparatus and method, infinitesimal changes in a deformable lens element's shape can result in large variation of a deformable lens element's optical properties
[00139] The described deformable lens element apparatus and method provide a number of advantages For example, relative to presently available optical systems incorporating exclusively non-deformable (rigid) lens elements, the presently described apparatus and method provides significant changes in optical properties while significantly reducing the amount of movement of a lens element required to produce the desired change in optical property (e g , focal length) By significantly reducing the amount of movement of a lens element for producing a desired change in optical property, the described apparatus and method facilitate increased miniaturization of an imaging system, and decreased energy consumption of a designed optica! system The above advantages are provided in a highly reliable, easily manufactured optical system that does not exhibit the reliability and manufacturing complexity disadvantages associated with previously proposed electro wetting and fluid injection fluid lens based optical systems
[00140] Various apparatuses are described herein having a deformable lens element that can be deformed by application of a force to an external surface thereof An illustrative embodiment of a described apparatus and method is shown in Fig I In the embodiment of Fig 1 , a deformable lens element 10 is provided by the combination of deformable membrane 3, spacer element 2, and boundary element I which can be provided by a piece of non-deformable glass, and a focus fluid (not shown) or other deformable substance (e g , a resiliency deformable volume) having an index of refraction greater than I The focus fluid or other deformable substance can be disposed within cavity 8 (as seen in Figs 2 and 3) defined by the combination of deformable membrane 3, spacer element 2, and transparent boundary element 1 as seen in Figs 2 and 3 Regarding the remaining elements of Fig 1 , the remaining elements are provided to apply a force to an external surface of lens element 10 Referring to the specific embodiment of Fig 1 , there is provided a pressure element 4 (a specific embodiment of which is referred to herein as a "push ring") for contacting deformable membrane 3, and an actuator element (actuator) 20 for actuating pressure element 4 Actuator 20 in the embodiment of Fig I is provided by an ion conductive electro-active polymer (EAP) Actuator 20 in the embodiment of Fig 1 includes a first conductor element 6a, a second conductor element 6b, and a deformable element 5 comprising a plurality of tab-like elements 5a interposed between the first conductor element 6a and second conductor element 6b First conductor element 6a includes an electrical contact (hidden from view in Fig 1 ) and second conductor element 6b also includes an electrical contact 6c The apparatus of Fig 1 , which may be termed a "focus module" or "focus apparatus" for use in focusing an image onto an image plane, can further include a housing 7 for housing the elements 10, 4, and 20 Referring again to deformable element 5 of actuator 20, deformable element 5 can comprise one or more layers of conductive polymer material such that tab-like elements 5a bend generally in the direction of axis 15 toward deformable lens element 10 responsively to an electrical signal being applied to conductor elements 6a and 6b Assembled form side views of apparatus 100 described in Fig 1 are shown in Figs 2 and 3
[00141 ] For varying the optical characteristics of deformable lens element 10, voltage can be applied to the electrical contacts of first conductor element 6a and second conductor element 6b to cause bending of tab-like elements 5a As indicated by the assembled form side views of Figs 2 and 3, tab-like elements 5a can be arranged to engage pressure element 4 so that when tab-like elements 5a bend toward deformable membrane 3, pressure element 4 applies a force to an external surface of deformable membrane 3 As is indicated by the views of Figs 1 -3, deformable lens element 10 can include a generally circle shaped surface provided in the embodiment shown by deformable membrane 3 and can include an axis 15 intersecting centers of opposing lens surfaces (provided in the embodiment shown by the exterior surfaces of membrane 3 and boundary element 1 ) Further, pressure element 4 can be ring-shaped so that pressure element 4 can apply a force generally in a direction coextensive with axis 15 at a plurality of points spaced apart from and peripherally disposed about axis 15 of lens element 10 Apparatus 100 can be adapted so that when tab-like elements 5a curve toward deformable membrane 3, membrane 3 bulges in a direction opposite the applied force to define a convex lens surface, as shown in Fig 2
[00142] In the embodiment of Figs 2 and 3, apparatus 100 has two states, namely, a "power off state in which tab-like elements 5a bias pressure element 4 toward membrane 3 to cause membrane 3 to bulge to define a convex lens surface and a "power on" state depicted in Fig 3 in which tab-like elements 5a pull pressure element 4 away from deformable membrane 3 so that deformable membrane 3 is allowed to assume a generally flat and non-convex configuration as best seen in Fig 3 For providing the control depicted in Figs 2 and 3, electro-active polymer actuator 20 can be provided so that tab-like elements 5a are normally biased toward deformable membrane 3 in the absence of voltage being applied to the contacts of actuator 20 and are biased in a direction generally parallel with the plane of membrane 3 (generally perpendicular to axis 15) when in a flat configuration as best seen in FIG 3 when a certain voltage is applied to the electrical contacts of electro-active polymer actuator 20 In the embodiment depicted in Figs 2 and 3, removal of voltage from conductor elements 6a and 6b causes tab-like elements 5a to urge pressure element 4 toward membrane 3, causing membrane 3 to bulge thereby changing an optical characteristic of deformable lens element 10
[00143] Further regarding the embodiment of Figs 1 -3, it is shown that deformable lens element 10 includes an axis 15 extending transversely therethrough and that actuator 20 applies a force to a surface of deformable lens element 10 in a direction generally coextensive with axis 15 In a further aspect, it is shown that pressure element 4 in the embodiment of Figs 1 -3 will contact deformable lens element 10 at a plurality of contact positions that are spaced apart from and peripherally disposed about axis 15 Referring to the embodiment of Figs 4 and 5, in the embodiment of Figs 4 and 5 clear boundary element 1 with first and second planar surfaces 1 10 and 1 1 1 as shown in Figs 2-3 is replaced with a boundary element 1 having an optical power Boundary element 1 of the embodiment of Fig 4 has an un-curved (planar) first surface 1 12 and a convex second surface 1 13 Boundary element 1 in the embodiment of Fig 5 has a concave first surface 1 14 and a convex second surface 1 15
[00144] In Figs 1 -3 a first apparatus for moving a deformable lens element 10 by application of a force to an external surface of the lens element is described Alternative apparatuses wherein a force can be applied to a deformable lens element 10 to cause variation in an optical characteristic (e g , lens element surface curvature, focal length) of a deformable lens element are now herein described
[00145] Referring now to the exploded assembly view of Fig 6, an alternative embodiment of focus apparatus 100 is shown and described In the embodiment of Fig 6, deformable lens element 10 is provided by a modular assembly described more fully herein, and actuator 20 (shown in the embodiment of Figs 1 -3 as being provided by an ion conductive electro-active polymer actuator) is provided in the embodiment of Fig 6 by a dielectric electro-active polymer actuator 20
[00146] Referring to actuator 20 in the embodiment of Fig 6, actuator 20 can comprise a flexible member 21 , a spring 23, a stopper 25 and flexible circuit board 27 for supplying voltage to flexible member 21 Referring to flexible member 21 , flexible member 21 can comprise a dielectric film material interposed between flexible electrodes which can be provided e g , by conductive carbon particles suspended in a polymer matrix When a voltage is applied to the flexible electrodes, flexible member 21 expands in the direction perpendicular to the electric field lines Spring 23 operates to bias flexible member 21 in a direction toward deformable lens element 10 Spring 23 shown as being provided by a conventional coil spring can substituted for by, e g , pressurized fluid or resilient foam Regarding stopper 25, stopper 25 operates to hold spring 23 at a certain position relative to flexible member 21 while flex circuit 27 supplies voltage to flexible member 21 having a distal end When power is applied to flex circuit 27, the operation of which is described more fully herein, flexible member 21 expands to push flexible member 21 in the direction of lens element 10 More specifically, when power is applied to flex circuit 27, flexible member 21 pushes pressure ring 4 toward deformable lens element 10 Pressure ring 4 driven by actuator 20 thereby deforms deformable lens element 10 to change an optical property of deformable lens element 10 As in the embodiment of Figs 1 -3, pressure element 4, (shown as being produced in a ring configuration) can be adapted to contact deformable lens element 10 at a plurality of positions about a periphery of deformable lens element 10 The plurality of contact positions are defined peripherally about and spaced apart from axis 15 of deformable lens element 10 As in the embodiment of Figs 1 -3, apparatus 100 in the embodiment of Fig 6 is adapted so that an optical property of a deformable lens element 10 is varied by applying a force generally in a direction of axis 15 at a plurality of contact points on deformable lens element 10 defined peripherally about axis 15
[00147] Referring to further aspects of the focus apparatus of Fig 6, focus apparatus 100 can be packaged with use of housing 17 sized and shaped to receive deformable lens element 10 in the modular assembly form shown in the embodiment of Fig 6 and cover 18 which can be adapted to be snap fit onto bolts 19a, 19b, 19c, and 19d Housing 17 can have a plurality of threaded holes aligned with holes of elements 21 , 25, and flex circuit 27 as shown Bolts 19a, 19b, 19c, and 19d can be driven through the aligned through holes and threaded into the shown threaded holes of housing 17 for assembly of apparatus 100 Focus apparatus 100 can be adapted so that one or more bolts 19a, 19b, 19c, and 19d conduct electrical current between flex circuit board 27 and flexible member 21 For example, flex circuit board 27 and flexible member 21 can be adapted so that bolt 19b connects a voltage terminal of flex circuit board 27 to a first flexible electrode of flexible member 21 and can further be adapted so that bolt 19c completes a conductive path between a second flexible electrode of flexible member 21 and flex circuit 27
[00148] Now referring to the embodiment of Figs 7-9, actuator 20 in the embodiment of Figs 7-9 is provided by a hollow stepper motor Referring to operation of actuator 20 of the embodiment of Figs 7-9 provided by a hollow stepper motor, supplying current through one or both of coil 31 or coil 33 causes hollow rotor 35 threadably received on stationary barrel 37 to rotate in such manner that by rotating rotor 35 advances in either direction along axis 15 depending on the signals applied to coils 31 and 33 In the manner as shown in the embodiment of Figs 1 -6, rotor 35 can be shaped so that an end of rotor 35 or a structure element transferring a force generated by rotor 35 contacts a surface of deformable lens element 10 at a plurality of positions peripherally disposed about and spaced apart from axis 15 thereof When rotor 35 in the embodiment of Figs 7- 9 is caused to rotate, rotor 35 while contacting deformable lens element 10 at such positions applies a force in a direction generally in the direction of axis 15 to cause an optical property of deformable lens element 10 to change The force generated by actuator 20 can be transferred to lens element 10 by pressure element 4 as shown in Figs 7-8 Pressure element 4, in the embodiment of Figs 7-9, can have opposing pins 4a which ride on complementaπly formed elongated slots 39 formed within barrel 37 so that rotation of pressure element 4 is resisted Further regarding focus apparatus 100 of the embodiment of Figs 7-9, focus apparatus 100 can further include a cap 38 threadably received on barrel 35 as shown Cap 38 has a transparent interior (not shown) to permit light to pass therethrough and forms a stopper resisting movement of deformable lens element 10 when rotor 35 is actuated to apply a force to an external surface of deformable lens element 10
[00149] Operation of actuator 20 in the hollow stepper motor embodiment of Figs 7-9 is now further described A hollow stepper motor, in one embodiment, generally is characterized by a permanent magnet equipped inner barrel, forming the rotor portion of the motor A hollow stepper motor, in one embodiment, can further be characterized by a coil equipped outer barrel, supporting the inner barrel (rotor) Hollow stepper motors exhibit reduced size relative to other types of motors and allow for precision adjustment of lens element positions In one embodiment, an inner barrel portion of a hollow stepper motor can include threads that are threadably received in threads of an outer barrel With such a thread arrangement, the motor can sustain high impact relative to gear based motor arrangements In one embodiment, threads for receiving an inner barrel in relation to an outer barrel can include threads complementaπly configured so that an inner barrel is maintained at a position with respect to outer barrel 37 by way of frictional forces and without application of external energy Accordingly, a lens setting can be controlled to remain at a certain setting simply by avoiding supplying current to a lens driver coil By comparison, alternative actuators, while desirable in some instances, require applied power for maintaining a fixed lens setting Accordingly, a major advantage of a hollow stepper motor, in one embodiment is reduced power consumption
[00150] Regarding outer barrel 37, outer barrel 37 can comprise a set of coils 32 corresponding to inner barrel 35 A set of coils 32 includes first coil 31 and second coil 33
[00151 ] Further, outer barrel 37 includes teeth 41 for engaging teeth 43 of inner barrel 35 The combination of teeth 41 and teeth 43 provide movement of inner barrel 35 along axis 15 when inner barrel 35 is caused to rotate
[00152] Operation of an exemplary hollow stepper motor is further described with reference to FIG 9 Inner barrel 35 can have permanent magnets 45 of alternating north and south polarity, which are alternately formed about the circumference of inner barrel 35 First coil 31 can have alternating teeth 47, 49 defined by gap 51 When current flows through coil 31 in a forward direction, magnetic fields of opposite polarity are formed at successively adjacent teeth, e g , teeth 47, 49 of coil 31 When current flows through coil 31 in a backward direction, magnetic fields of opposite polarity are again formed at successively adjacent teeth of coil 31 , except the polarity of the magnetic field is the opposite of its polarity during forward direction current flow Similarly, second coil 33 can have alternating teeth 55, 57 defined by gap 59 When current flows through coil 33 in a forward direction, magnetic fields of opposite polarity are formed at successively adjacent teeth When current flows through coil 33 in a backward direction, magnetic fields of opposite polarity are again formed at successively adjacent teeth of coil 33, except the polarity of the magnetic field is the opposite of its polarity during forward direction current flow [00153] For rotating inner barrel 35, current can be applied in forward and backward direction in first and second coil 31 , 33 in a timed sequence coordinated manner to urge inner barrel 35 in a desired direction until a desired position of barrel 35 is achieved When teeth of coil 31 or coil 33 have a certain polarity, it is seen that inner barrel 35 will have a certain position relative to outer barrel 37 such that permanent magnets thereof are aligned with teeth of coil 31 or coil 33 Thus, using the actuator 20 of FIGS 7-9, precise positioning of lens elements can be achieved The motor described with reference to FIGS 7-9 is referred to as a hollow stepper motor since discrete stepwise positions of inner barrel 35 relative to outer barrel 37 can be achieved wherein permanent magnets of the barrel are aligned with coil teeth having a certain polarity
[00154] With the end of inner barrel 35 being generally ring-shaped in the manner of pressure element 4, actuator 20, as shown in the embodiment of Figs 7-9 can operate substantially in the manner of the embodiment of Figs 1 -3, and of Fig 6 That is, actuator 20 as shown in Figs 7-9 can apply a force generally in the direction of axis 15 For application of the force, deformable lens element 10 as shown in Fig 5 can be contacted at a plurality of contact positions defined on an exterior surface of deformable lens element 10 at a plurality of points spaced apart from axis 15 and peripherally disposed about axis 15
[00155] Specific examples of various constructions of deformable lens element 10 which can be interchanged into any one of the embodiments of focus apparatus 100 described are described herein in connection with Figs 10- 17
[00156] In the embodiment of Fig 10, deformable lens element 10 comprises first clamping element 63 second clamping element 65 and deformable membrane 3 interposed between first clamping element 63 and second clamping element 65 Each of the first and second clamping elements 63 and 65 can be transparent (optically clear) and disk shaped as shown and can include respective annularly disposed interlocking teeth Specifically in the embodiment shown, clamping element 63 includes three annularly formed tooth rings 64 and clamping element 65 includes a pair of annularly disposed tooth rings 66 as best seen in Figs 1 1 - 12 that engage the teeth of the clamping element 63 While in the embodiment shown a plurality of annular rings are provided on each of clamping element 63 and clamping element 65 it is seen that a holding force between clamping element 63 and clamping element 65 would be aided by the presence of a fewer number of tooth rings, e g , only a single annular tooth ring on one of the clamping elements In such manner membrane 3 is clamped between clamping element 63 and clamping element 65
[00157] For assembly of the deformable lens element of Figs 10- 12, clamping element 65 can be press fit onto clamping element 63 and then can be ultrasonically welded thereto In another aspect clamping element 63 and clamping element 65 can have complementary tongue and groove engaging surfaces at which an ultrasonic weld can be formed In the embodiment of FIGS 10- 12, clamping element 63 includes an annular groove 71 (Figs 10- 12) and clamping element 65 includes an annular tongue 73 (Figs 10- 12) However, in an alternative embodiment, the location of the tongue and groove can be reversed The ultrasonic weld at the interface between tongue and groove can be supplemented or replaced e g , with an adhesive suitable for use with the material of the clamping elements Planar optically clear window 67, as shown in the embodiment of Fig 1 1 , can be replaced with a curved surfaced member having an optical power An alternative window for use with the deformable lens element as shown in Figs 10- 12 can have, e g , the curved surfaces of element 1 , as shown in Figs 4 (surfaces 1 12 and 1 13) and Fig 5 (surfaces 1 14 and 1 15) herein
[00158] In another aspect, clamping element 63 can have a transparent wall 67 allowing light to pass therethrough and can have a sufficient thickness to define a cavity 8 for receiving focus fluid or another deformable substance After clamping element 63 and clamping element 65 are ultrasonically welded, focus fluid having an index of refraction greater than 1 (where the lens element incorporates a focus fluid) can be input into cavity 8 through hole 75 After the cavity is filled, the hole 75 can be sealed Regarding clamping element 63 and clamping element 65 each of clamping element 63 and clamping element 65 can be formed of solid non-deformable material Further, clamping element 65 can define an aperture 77 to allow a force supplying element {e g , pressure element 4 or actuator 20 if pressure element 4 is deleted) to contact membrane 3
[00159] Another embodiment of deformable lens element 10 is shown and described in Fig 13 In the embodiment of Fig 13, deformable lens element 10 has a pair of deformable lens surfaces, namely, a first surface defined by first deformable membrane 3 and a second surface defined by second deformable membrane 3' Deformable lens element 10 in the embodiment of Fig 13 is constructed in the manner of the deformable lens element 10 of Figs 10- 12 except that clamping element 63 holding deformable membrane 3 is repeated and clamping element 63 is modified for receipt of second membrane 3' and a second clamping element 65 on an opposite side thereon In the embodiment of Fig 13, it is seen that deformable lens element 10 has teeth as described in connection with the embodiment of Figs 10- 12 for securely holding membranes and annular tongue and groove fasteners formed therein for securely holding a clamping element in relation to clamping element Regarding window 67' of center clamping element 63', and where the lens element 10 incorporates a focus fluid, the window 67' can be formed so that a first and second fluid tight cavity for holding focus fluid are defined in the deformable lens element 10 of Fig 13 Alternatively, the first and second cavities can be in fluid communication e g , by way of through holes formed in a window 67' Also, window 67' can be deleted and the cavities can be in fluid communication through an aperture defined by the inner most annular tooth ring of center clamping element 63'
[00160] Regarding Fig 14, Fig 14 shows an embodiment of a focus apparatus 100 incorporating the deformable lens element 10 shown in Fig 13 wherein both of a light entry and light exit surface of the lens element 10 are deformable Regarding the embodiment of Fig 14, focus apparatus 100 can have a pair of actuators 20 disposed on either side of deformable lens element 10 including deformable membrane 3 and deformable membrane 3' A first actuator 20 can be disposed as shown to impart a force on an exterior surface of first membrane 3 which may define a light entry surface of deformable lens element 10 and a second actuator 20 can be disposed as shown to impart a force on an exterior surface of second membrane 3' which may define a light exit surface of lens element 10 In the embodiment of Fig 14, both of the first and second actuators can have the characteristics described with reference to the embodiment of Figs 1 -3 For example, both of the actuators 20 can be disposed so that an aperture 16 of the actuator 20 is disposed about an axis 15 of deformable lens element 10 Each of the actuators 20 can be further arranged so that a force generated by the actuator 20 is imparted to the lens element 10 in a direction generally coextensive with axis 15 and further so that the deformable surface of the deformable lens element 10 is in contact at a plurality of contact positions spaced apart from and peripherally disposed about axis 15 In one embodiment of an optical system incorporating the lens element 10 of Fig 13, membrane 3 can form a light entry surface of the lens element and membrane 3' can form a light exit surface In another embodiment, lens membrane 3' forms a light entry surface of the lens element and membrane 3 forms a light exit surface
[00161 ] Further regarding the focus apparatus 100, it is seen that the first and second actuators 20 have apertures 16 disposed about, and in one embodiment, substantially centered on axis 15 of deformable lens element 10 in such manner that a first of the actuators imparts a force in a direction generally coextensive with the axis 15 on a light entry deformable lens surface of the lens element while a second of the actuators 20 imparts a force in a general direction of axis 15 on a light exit surface of the deformable lens element 10
[00162] It is seen that the deformable lens element 10 of Fig 13 arranged with appropriate actuators as shown in Fig 14 can be controlled to exhibit a variety of major lens element configurations, e g planar convex, planar concave, bi-convex, bi-concave, concave-convex, meniscus, bi-convex with non-equal surface power
[00163] Regarding deformable membrane 3 and membrane 3' in the various embodiments of deformable lens element 10, the deformable membranes can comprise nonporous optically clear elastomer material A suitable material for use as membrane 3, 3' is SYLGARD 184 Silicon elastomer, of the type available from DOW CORNING
[00164] Regarding cavities 8 described in the various embodiments, cavities 8 can be filled with optically clear focus fluid Selecting a focus fluid with a relatively high index of refraction will reduce the amount of deformation needed to obtain a given change in focal distance In one example, a suitable index of refraction would be in the range of from about 1 3 to about 1 7 Selecting a focus fluid with a smaller index of refraction is advantageous where it is desired to increase the amount of deformation needed to obtain a given change in focal distance For example, in some embodiments where a selected actuator 20 generates relatively coarse movements, a focus fluid having a lower index of refraction might be selected One example of a suitable focus fluid (optical fluid) is SL-5267 OPTICAL FLUID, available from SANTOLIGHT, refractive index = 1 67
[00165] Further regarding cavities 8 of the various embodiments, the cavities can be filled with an alterative deformable optically clear substance having an index of refraction greater than 1 that does not, in the manner of a fluid, assume the shape of its respective cavity 8 when of greater volume than the substance For example, a deformable shape retaining material which can substantially retain its unstressed shape throughout its lifetime can be disposed in cavity 8 in each of the various embodiments of deformable lens element 10
[00166] In one example, a silicon gel can be provided as a resilien y deformable shape retaining material that substantially retains its unstressed shape over the course of its lifetime A resiliently deformable silicon gel can be disposed in cavity 8 of any of the described embodiments For manufacture of a suitable silicon gel for use with a deformable lens element 10 described herein, liquid silicon can be filled into a container of the desired shape of completed gel member and then cured In one example, the liquid silicon can be filled into a mold in the shape of cavity 8 into which the silicon gel member will be disposed, and then cured until in silicon gel form [00167] Further, with reference to manufacture of a resiliency deformable member, a mold core can be prepared with aluminum by single point diamond turning and nickel plating The cavities can have the negative shape of the resiliency deformable lens element to be made Next, a silicon gel mixture can be prepared such as DOW CORNING JCR61 15 two part silicon Heat Cure gel The two parts, JCR61 15 CLEAR A and JCR61 15 CLEAR B are mixed to form a mixture The mixture can be vacuumed to release bubbles formed therein With the liquid silicon gel prepared, the liquid silicon gel can be injection molded into the mold core The liquid silicon gel can then be cured under an elevated temperature Where JCR61 15 liquid silicon available from DOW CORNING is used, the liquid gel can be cured by heating for 5 minutes at 175 degrees The completed silicon gel lens can then be inspected to determine whether it is free of defects and extra material can be removed around the gate area Optionally, the finished resiliency deformable member can be spin coated with a thin membrane material e g , SYLGARD 184 from DOW CORNING to improve durability Several materials that can be utilized in the form of a resiliency deformable member for as in a deformable lens element or component thereof are summarized in Table A below In each of the exemplary embodiments, the material constituting a major body of a deformable lens element (including some instances the entire resiliency deformable lens element) has a hardness measurement of less than Shore A 60
Table A
Figure imgf000020_0001
[00168] In each of the exemplary embodiments, the material forming a resiliently deformable member is provided by an optically clear silicon gel elastomer having an index of refraction greater than 1 However, it will be understood that any optically clear resiliently deformable material having an index of refraction greater than 1 can be utilized in the manufacture of a deformable lens element
[00169] When in a silicon gel form the formed silicon gel member can be disposed in cavity 8 It will be seen that whereas filling focus fluid and sealing can normally be last steps in a lens element manufacturing method where a lens element incorporates a fluid, disposing a gel member in a cavity can normally be an intermediate step in the manufacture of a gel based deformable lens element [00170] Referring to Fig 15, another embodiment of deformable lens element 10 is illustrated The embodiment of Fig 15 has a construction similar to that of the embodiment of Figs 10-12 with resiliently deformable lens member 80 disposed (e g , comprising silicon gel) in a cavity delimited by clamping member 63 and clamping member 65 in place of focus fluid Further regarding the embodiment of Fig 15, pressure element 4 provided by a push ring is mechanically coupled to clamping member 65 for purposes of aiding the alignment of pressure element 4 with deformable membrane 3
[00171 ] Where a deformable lens element incorporates a deformable shape retaining material such as can be provided by silicon gel, features of deformable lens element 10 for sealing of cavity 8 can be optionally deleted In the embodiment of Fig 16, cavity 8 is deleted and deformable lens element 10 comprises a stacked layer construction including resiliently deformable material member 80, deformable membrane 3, back plate 81 and forward plate 82 adapted to mechanically couple pressure element 4 as shown
[00172] Where deformable lens element 10 incorporates a shape retaining resiliently deformable member such as a deformable member comprising silicon gel as described herein, deformable membrane 3 can be optionally deleted Nevertheless, with membrane 3, resiliently deformable member 80 may be advantageously protected and the incidence of scratches on the surface of resiliently deformable member 80 can be reduced Additionally or alternatively for protecting resiliently deformable member 80, member 80 may be subject to a coating processing wherein optically clear protective coating 84, such as may comprise SYLGARD 184 from DOW CORNING can be applied to gel member 80 as has been described herein An example of a deformable lens element 10 comprising a resiliently deformable member 80 and a surface protective coating 84 is shown in Fig 17
[00173] It has been mentioned that a process for manufacture of a shape retaining resiliently deformable optically clear member can include filling a container of a desired shape of the finished member and then curing In one embodiment, a shape retaining resiliently deformable member, as described herein can be formed to have an initial optical power In one embodiment, a shape retaining resiliently deformable member can be formed so that in an unstressed state the deformable member has at least one convex lens surface
[00174] In the embodiment of a focus apparatus 100 as shown in Fig 18, resiliently deformable member 80 can be formed to have an initial optical power, and is specially configured so that in an unstressed state resiliently deformable member 80 has a first normally (unstressed state) convex surface 85 and a second normally (unstressed state) convex surface 86 One of the lens surfaces 85 or 86 can be regarding as a light entry surface and the other a light exit surface Further respecting the focus apparatus 100 of Fig 18, first and second electro-active polymer actuators 20 can be disposed to deform each of the first and second normally convex surfaces In one embodiment of Fig 18, lens element 10 is shown as being provided as a one piece member consisting of resiliently deformable member 80 In the embodiment of Fig 18, as well as in the remaining embodiments described wherein a major body of the deformable lens element 10 comprises a resiliently deformable material member, deformable lens element 10 can be devoid of a focus fluid
[00175] In the exemplary embodiment of Fig 18, actuators 20 for deforming deformable lens element 10 can comprise dielectric electro-active polymer flexible members 21 as described previously in connection with the embodiment of Fig 6 In the embodiment as shown in Figs 18- 19, flexible members 21 are normally biased outward by resiliently deformable member 80 and hence spring 23 is not included in the embodiment of Figs 18 and 19 Also, pressure element 4 is deleted in the embodiment of Figs 18 and 19 and the force imparting structural element in the embodiment of Fig 18 and Fig 19 is provided by actuator 20 Each flexible member 21 can be disposed to contact deformable lens element 10 provided in the embodiment of Figs 18 and 19 by a one piece resiliently deformable member which in one embodiment comprises a silicon gel Specifically with reference to the embodiment of Figs 18 and 19, each flexible member 21 can be adapted to substantially conform to the unstressed shape of a deformable lens element provided in the embodiment shown by a one piece resiliently deformable member 80 As in the embodiment of Fig 18, each flexible member 21 can include dielectric film material layer 90 interposed between a pair of flexible electrode layers 91 and 92 such that by varying the voltage between the flexible electrode layers, the flexible member expands or contracts In another embodiment the single dielectric layer 90 can be replaced by multiple dielectric layers Further referring to the focusing apparatus 100 of Fig 18, each flexible member 21 can include an uncoated area 1 16 disposed about lens element axis 15 to allow light rays to pass through deformable lens element 10
[00176] Uncoated areas 1 16 in the embodiment of Fig 18 are areas devoid of flexible electrode coating which coating can cover the remainder of the internal and external surfaces of flexible member 21 in areas other than the uncoated areas 1 16 For providing dielectric layer 90 in an optically clear form for permitting light to pass there through, dielectric layer 90 can comprise a suitable optically clear material, examples of which include Acrylic, model number VHB4910, available from 3M, and model number CF19-2186 Silicon available from NUSIL For manufacture of a flexible member 21 as shown in the embodiment of Fig 18, an optically clear muscle dielectric material can be spin cured on a carrier substrate (glass plate) to form a uniform thin film The film can then be cured at an elevated temperature After curing, the film can be detached from the substrate and electro-chemically coated to form a flexible electrical coating except in uncoated areas 1 16 The formed flexible member can be cut to appropriate size and mounted In a further aspect, when voltage is applied to contract a flexible member 21 , the resulting force initially generated in a direction generally perpendicular to axis 15 is imparted to deformable lens element 10 generally in the direction of axis 15 toward lens element 10 in such manner that the convexity of lens element is increased With apertures 16 ring-shaped and disposed about axis 15 and with flexible member 21 adapted to substantially conform to the shape of deformable lens element, a contraction of a flexible member 21 results in forces generally in the direction of axis 15 toward deformable lens element being imparted at a plurality points peripherally disposed about and spaced apart from axis 15 While the force imparted to lens element 10 by actuators 20 in the embodiment of Fig 18 can be described as being generally in the direction of lens element axis 15, it is understood that if the forces imparted are broken down into normal (axis directed) and transverse (perpendicular to axis 15) constituent component force vectors in the embodiment of Fig 18 can be expected to have a higher percentage of transverse component force vectors than in the embodiments described herein with reference to Figs 1 -9
[00177] Further regarding focus apparatus 100 as described in Fig 18, voltage terminals can be provided in such manner as to appropriately supply voltages across the flexible electrode layers 91 and 92 of the respective first and second flexible members 21 shown Voltage terminals as will be described in an exemplary embodiment can also be provided to structurally support flexible members 21 in a certain position in relation to lens element 10 and the flexible members 21 in turn support resiliently deformable lens element 10 In the embodiment shown in Fig 18, imaginary lines connecting terminal connecting interfaces 125 and interfaces 127 (where a first flexible member 21 is connected to conductive rings 94 and 98 and a second flexible member is connected to conductive rings 98 and 96) can bisect deformable lens element 10 In such manner the flexible member 21 in the embodiment shown can impart a force generally in the direction of axis 15 toward lens element 10 when controlled to move to a contracted state
[00178] The components of the embodiment of Fig 18 are further described with reference to Fig 19 showing an exploded assembly view of the embodiment in accordance with Fig 18 Referring to the view of Fig 19, it is further seen that focus apparatus 100 includes bi-convex resilient (shape-retaining) deformable lens element 10 provided by one piece deformable member 80 interposed between a pair of flexible members 21 of first and second actuators 20 adapted to substantially conform to the shape of deformable lens element 10 when in an unstressed state Referring to further aspects of focus apparatus 100 as shown in Fig 19, focus apparatus 100 can further include housing elements 93, conductive rings 96 and 94, insulating sleeve 97, and center conductive rings 98 Conductive ring 94, center ring 98, and conductive ring 96 are fitted inside insulating sleeve 97, which is disposed to prevent a short between housing element 93 and conductive ring 94 and between housing element 93 and center conductive ring 98 In a further aspect, conductive ring 96 can be in conductive contact with conductive housing element 93 For actuating of first and second actuators 20 having first and second flexible members 21 , a voltage can be applied across housing 93 (in conductive contact with conductive ring 96) and conductive ring 94 In the embodiment shown, center conductive ring 98 operates as a node in a series circuit that comprises the respective dielectric layers of a first flexible member 21 and second flexible member 21 , wherein the node connects the noted elements Application of a voltage across housing 93 (and therefore ring 96) and ring 94 can cause the first (disposed between ring 94 and ring 98) and second (disposed between ring 96 and ring 98) flexible members 21 to be actuated simultaneously In another embodiment center conductive ring 98 can be in electrical communication with a reference voltage and voltages can be applied between the conductive ring 96 and ring 98 and also between ring 94 and ring 98 for independent control of the first and second flexible members 21 of the first and second actuators 20 The various elements of Figs 18 and 19 can be sized to be frictionally fit so that the elements are in certain relative position when apparatus 100 is fully assembled
[00179] In another embodiment, the dielectric electro-active polymer actuator as shown in Figs 1 8- 19 can be replaced by an ion conductive electro-active polymer actuator, as described previously herein An ion conductive polymer actuator can have the configuration of the actuator as depicted in Figs 18- 19, except that optically clear dielectric layer 90 can be replaced with one or more optically ion conductive polymer layers
[00180] Where the actuator 20 as shown in Figs 18- 19 represents a dielectric electro-active polymer actuator the actuator can generate force (by contraction of the actuator) in a direction generally perpendicular to axis 15, which force is imparted to a deformable surface of lens element 10 in a direction that is generally in the direction of axis 15 Where actuator 20 in the embodiment of Figs 18- 19 represents an ion conductive polymer actuator, the actuator can generate a force in a direction generally in the direction of axis 15 (by bending of the ion conductive layer) which force is imparted to a deformable surface of lens element generally in the direction of axis 15 The voltage requirements of focus apparatus 100 can be reduced (e g , to less that 10 volts) with selection of an ion conductive electro-active polymer actuator
[00181 ] In the embodiments having an electro-active polymer actuator 20 with an uncoated area region 1 16 (e g , either of the dielectric type or an ion conductive type), the uncoated area 1 16 can be replaced with an aperture 16 so that the actuator 20 operates in the manner of a force imparting structural element having an aperture 16 as described herein
[00182] Also embodiments herein having force imparting elements including an aperture, the aperture 16 can be filled with an optically clear material member so that the force imparting structural element operates in the manner of the actuator of Figs 18- 19 As has been described herein, the actuator in any of the described embodiments can be substituted for by an actuator of any of the remaining embodiments Likewise the deformable lens element in any of the described embodiments can be substituted for by a deformable lens element of any of the remaining embodiments
[00183] While the embodiments of Figs 18 and 19 include a deformable bi-convex lens element and an actuator for deforming each of a pair of lens surfaces, it is seen that focus apparatus 100 could alternatively comprise a plano-convex resiliently deformable shape-retaining lens element and a single actuator for deforming the normally convex lens surface
[00184] In any of the described embodiments wherein a force generated by actuator 20 is transferred to deformable lens element 10 by pressure element 4, it is understood that pressure element 4 can be deleted and that a force generated by actuator 20 can be imparted on deformable lens element 10 directly by actuator 20 For imparting a force on deformable lens element 10, it has been described that a structural element, namely pressure element 4 or actuator 20 (if the focus apparatus is devoid of pressure element 4), can "contact" a deformable lens element at a plurality of contact positions, or otherwise impart a force to a deformable lens element at a plurality of force impartation points
[00185] In one embodiment of a "contacting" relationship between a structural element and deformable lens element as described herein, the force-applying structural element can be in separable contact with the deformable lens element, meaning that the force supplying the structural element can be freely separated from the deformable lens element In another embodiment of a "contacting" relationship described herein, the force- applying structural element can be in secure contact with the deformable lens element, meaning that it is adhered to, welded to, biased toward, or otherwise connected to the deformable lens element
[00186] In another embodiment, the force-applying structural element, (e g , the actuator or pressure element) is integrally formed with the deformable lens element, meaning that the force applying structural element is part of a one piece member, a part of which forms the force applying structural element, and a part of which forms at least a part of deformable lens element 10
[00187] Where the force applying structural element is in secure contacting relationship with a deformable surface of the deformable lens element or is integrally formed with the deformable surface, a pulling force generated by actuator 20 (ι e , in the direction of axis 15 but away from deformable lens element 10) can operate to deform the deformable lens element A pulling force imparted on a surface of a deformable lens element imparted at a plurality of points peripherally disposed about and spaced apart from axis 15 can be expected to decrease a convexity or increase a concavity of the deformable surface where the force applying structural element is ring shaped Where a force applying structural element (member) is ring shaped as described herein, the force applying structural element can impart a force to a deformable lens element at a plurality of points spaced apart from and peripherally disposed about axis 15 of lens element 10 The force applying structural element can impart a force at a plurality of points spaced apart from and peripherally disposed about axis 15 whether the force applying element is in separable contacting, secure contacting, or whether the force applying structural elements is integrally formed with the deformable lens element Force can be imparted to a deformable surface of a deformable lens element at a plurality of force impartation points having characteristics that vary depending on the shape of the force imparting structural element Where the force imparting element is ring shaped, a plurality of force impartation points can be formed in a ring pattern about axis 15 Ring shaped force imparting elements as described herein have been shown as being circular, however, ring shaped force applying elements can also be oval, asymmetrically arcuate, or polygonal Where a force imparting element is ring shaped, force imparting points of a deformable surface, at least a part of which transmits image forming light rays, do not include points within a two dimensional area about axis 15 delimited by the plurality of force imparting points in a ring pattern peripherally disposed about axis 15
[00188] In the embodiment of Figs 18 and 19, an actuator can impart a force to deformable surface of a deformable lens element generally in the direction of axis 15, however, in the embodiment of Figs 18 and 19, the force impartation points are not formed in a ring pattern that excludes points within a two dimensional area about axis 15 In the embodiment of Figs 18 and 19, force impartation points include points within a two dimensional area about axis 15 of a deformable surface at least part of which transmits image forming light rays In one embodiment, the force impartation points can be points of a surface of deformable lens element 10 facing an exterior of deformable lens element 10 Force impartation points in various examples are depicted in Figs 20 and 21 , wherein Fig 20 shows an exemplary view of force impartation points being defined in a ring pattern 202 at a plurality of points peripherally disposed about and spaced apart from axis 15, and Fig 21 shows an exemplary depiction of force impartation points defined in an area pattern 204, wherein force impartation points include points defining a two dimensional area about axis 15 Characteristics of exemplary force impartation profiles are described further in connection with Table B Where a force imparting element is ring shaped, a pushing force imparted to a deformable surface of deformable lens element 10 in a direction of the element 10 can increase a convexity of the surface by encouraging the surface to bulge outwardly along an axis and decrease in thickness along a plurality of imaginary lines that run parallel to the axis, and which are spaced apart from and peripherally disposed about axis 15 Where an area force imparting element e g , as shown in the embodiment of Figs 18 and 19, is utilized, imparting a pushing force in the direction of deformable lens element 10, and the deformable element is normally convex, the imparted force results in flattening, or a reduction of the convexity of the surface Further characteristics of embodiments having the described exemplary force impartation profiles are summarized in Table B TABLE B
Figure imgf000026_0001
[00189] In the embodiment of Figs 1 - 19, focus apparatus 100 can be adapted so that an infinitesimal change in the position of actuator 20 provides a significant change in the focus position of an optical imaging system in which apparatus 100 is incorporated Specific performance characteristics that can be realized with use of focus apparatus 100 as described herein are described with reference to the following example [00190] It will be seen from the embodiments of Figs 1 - 19 that the actuator and lens elements can be interchanged in any combination among the embodiments
EXAMPLE I
[00191 ] A focus apparatus for use in focusing having a structure substantially according to that shown in Fig 6 is constructed and fitted onto a lens triplet imaging lens assembly of an IT5000 Image Engine of the type available from Hand Held Products, lnc having a focal length of 5 88mm, an F# of 6 6 and a nominal fixed best focus distance of 36 inches An actuator from ARTIFICIAL MUSCLE INCORPORATED ("AMI") based on the design of an MLP-95 or MSP-95 auto-focus muscle actuator available from AMI, lnc was used After the focus element was constructed, various voltages were applied to the actuator's flexible electrodes The results are summarized in Table C below
TABLE C
Figure imgf000027_0001
[00192] It was observed that large variations in the best focus distance could be realized with infinitesimal movement of an actuator applying a force to a deformable lens element
[00193] [End of Example 1 ]
[00194] Various arrangements of the described deformable lens element in various imaging systems are now described
[00195] Apparatus 100 comprising deformable lens element 10 moveable by way of force applied to an external surface thereof can be incorporated in an optical imaging system (which may alternatively be termed a lens assembly) comprising apparatus 100 and one or more additional lens elements arranged in a series with the apparatus The one or more additional lens elements can comprise deformable or non-deformable lens elements When apparatus 100 is arranged in series with a far focused imaging lens assembly (not shown) focused at infinity, the state (lens without curvature or planar) depicted e g , in Fig 3 will achieve a far focus and the state depicted in Fig 2 (convex lens) will achieve a near focus
[00196] In the embodiment of Fig 22, lens assembly 500 (which can also be referred to as an "optical imaging system") for transmission of image forming light rays comprises a single deformable lens element 10 disposed in a focus apparatus 100 according to any one of the embodiments discussed herein For increasing an optical power of an imaging lens assembly comprising a single deformable lens element, the lens element can be provided in a form capable of double convex configuration In the embodiment of Fig 23, imaging system 500, for transmission of image forming light rays, comprises a single deformable lens element 10 disposed in a focus apparatus 100 according to any one of the embodiments discussed herein in combination with subassembly 502 More specifically, focus apparatus 100 as shown in Fig 23 is disposed in series with a lens subassembly 502 comprising one or more (as indicated by the dashed in element) rigid non-deformable lens elements 1 1 Regarding lens assembly 500 as shown in Fig 23, focus apparatus 100 can be an add-on unit detachably received on lens subassembly 502 In the embodiment of Fig 24, lens assembly 500 comprises a plurality of deformable lens elements 10 disposed in a modified focus apparatus 100' modified to include actuators for actuating a plurality of deformable lens elements 10 Lens assembly 500 in the embodiment of Fig 24 further comprises a plurality of rigid non-deformable lens elements 1 1 Lens assembly 500 in each of the embodiments of FIGS 22, 23, and 24 is disposed in association with an object plane 540, and an image plane 550 partially defined by image sensor 1032 Image sensor 1032 can be shielded from stray light rays by shroud 560, which can be integrally formed with a housing of lens assembly 500 Where lens assembly 500 includes more than a single deformable lens element 10, such additional lens elements can be aligned such that the axes of such additional elements are coincident with axis 15 Accordingly, where lens assembly 500 includes a plurality of lens elements, axis 15 can, as shown in Figs 23 and 24, be regarded as an optical or imaging axis of lens assembly 500
[00197] Turning now to Fig 25, a block diagram of an illustrative imaging terminal 1000 incorporating a lens assembly 500 as described herein is shown and described Lens assembly 500 can be incorporated in an imaging terminal 1000
[00198] An electrical component circuit diagram supporting operations of imaging terminal 1000 is shown in FIG 25 Image sensor 1032 can be provided on an integrated circuit having an image sensor pixel array 1033 (image sensor array), column circuitry 1034, row circuitry 1035, a gain block 1036, an analog-to-digital converter (ADC) 1037, and a timing and control block 1038 Image sensor array 1033 can be a two dimensional image sensor array having a plurality of light sensitive pixels formed in a plurality of rows and columns Each sensor element of the image sensor array 1033 can convert light into a voltage signal proportional to the brightness The analog voltage signal can then be transmitted to the ADC 1037 which can translate the fluctuations of the voltage signal into a digital form The digital output of the ADC 1037 can be transmitted to a digital signal processor (DSP) 1070 which can convert the image into an uncompressed RGB image file and/or a standard or proprietary image format before sending it to memory Terminal 1000 can further include a processor 1060, an illumination control circuit 1062, a lens assembly control circuit 1064, an imaging lens assembly 500, a direct memory access (DMA) unit (not shown), a volatile system memory 1080 (e g , a RAM), a nonvolatile system memory 1082 (e g , EPROM), a storage memory 1084, a wireline input/output interface 1090 (e g , Ethernet), short range RF transceiver interface 1092 (e g , IEEE 802 1 1 ), and a long range radio transceiver interface 1093 (e g , GPRS, CDMA) for use m e g , providing cellular telephone data communications Regarding illumination control circuit 1062, illumination control circuit 1062 can receive illumination control signals from processor 1060 and can responsively deliver power to one or more illumination light sources such as illumination light sources 604, and one or more aiming light sources such as aiming light sources 610 Terminal 1000 can be adapted so that light from light sources 604, 610 is projected onto a substrate within a field of view of terminal 1000 Terminal 1000 can also include a keyboard 1094, a trigger button 1095, and a pointer controller 1096 for input of data and for initiation of various controls and a display 1097 for output of information to an operator Terminal 1000 can also include a system bus 1098 for providing communication between processor 1060 and various components of terminal 1000
[00199] In one embodiment, imaging terminal 1000 can have software and hardware enabling terminal 1000 to operate as a mobile telephone For example, the terminal 1000 can include a microphone 1077 and speaker 1078 in communication with processor 1060 over system bus 1098 Terminal 1000 can also have connected to system bus 1098 long range radio transceiver interface 1093 enabling transmittal and receipt of voice packets over a cellular data communication network
[00200] DSP 1079 can encode an analog audio signal received from microphone 1077 to a digital audio signal to be transmitted to processor 1060 DSP 1079 can also decode an analog audio signal to be transmitted to speaker 1078 from a digital audio signal received from processor 1060 In one embodiment, all the essential functions of the audio signal encoding and decoding can be carried on by DSP 1079 In another embodiment, at least some of the audio encoding/decoding functions can be performed by a software program running on processor 1060
[00201 ] Imaging terminal 1000 can also be adapted to operate as a video camera For operation as a video camera, DSP 1070 can be adapted to convert the sequence of video frames captured by the image sensor 1032, into a video stream of a standard or proprietary video stream format (e g , MJPEG, MPEG-4, or RealVideo™) before transmitting it to volatile memory 1080 or storage memory 1084 The recorded video files can be played back via the display 1097 or transmitted to an external computer
[00202] Operational characteristics of an exemplary imaging terminal and its processing of image signals are now further described In response to control signals received from processor 1060, timing and control circuit 1038 can send image sensor array timing signals to array 1033 such as reset, exposure control, and readout timing signals After an exposure period, a frame of image data can be read out Analog image signals that are read out of array 1033 can be amplified by gain block 1036 converted into digital form by analog-to- digital converter 1037 and sent to a digital signal processor (DSP) which can convert the image into an uncompressed RGB image format or a standard or proprietary image format (e g , JPEG), before sending it to volatile memory 1080 In another embodiment, the raw image can be sent to the memory 1080 by ADC 1037, and the converting of the image into a standard or proprietary image format can be performed by processor 1060 Processor 1060 can address frames of image data retained in RAM 1080 for decoding of decodable indicia represented therein
[00203] A timing diagram further illustrating operation of terminal 1000, in one embodiment, is shown in FIG 26 Timeline 1202 shows a state of a trigger signal which may be made active by depression of trigger button 1095 Terminal 1000 can also be adapted so that a trigger signal can be made active by the terminal sensing that an object has been moved into a field of view thereof or by receipt of a serial command from an external computer Terminal 1000 can also be adapted so that a trigger signal is made active by a power up of terminal 1000 For example, in one embodiment, terminal 1000 can be supported on a scan stand and used for presentation reading In such an embodiment, terminal 1000 can be adapted so that a trigger signal represented by timeline 1202 can be active for the entire time terminal 1000 is powered up Terminal 1000 can be adapted so that trigger signal 1202 can be maintained in an active reading state (indicated by the signal 1202 remaining high) by maintaining trigger button 1095 in a depressed position In one embodiment, where terminal 1000 is adapted to read decodable indicia, terminal 1000 can be adapted so that depressing trigger 1095 drives trigger signal 1202 into an active state where it remains until the earlier of (a) the trigger button 1095 is released, or (b) a decodable indicia is successfully decoded
[00204] With further reference to the timing diagram of Fig 26, terminal 1000 can be adapted so that after a trigger signal is made active at time 1220, pixels of image sensor 1032 are exposed during first exposure period EXP| occurring during a first time period followed by second exposure period EXP2 occurring during a second time period, third exposure period EXP3 occurring during a third time period and so on (after time 1220 and prior to first exposure period EXP, , parameter determination frames subject to parameter determination processing may be optionally captured subsequent to parameter determination exposure periods that are not indicated in Fig 26) Referring to the timing diagram of FIG 26, terminal 1000 may expose, capture, and subject to unsuccessful decode attempts N- I frames of image data prior to successfully decoding a frame of image data corresponding to exposure period EXPN An exposure control signal in one embodiment is represented by timeline 1204 of Fig 26
[00205] Terminal 1000 can be adapted so that after pixels of image sensor array 1033 are exposed during an exposure period, a readout control pulse is applied to array 1033 to read out analog voltages from image sensor 1032 representative of light incident on each pixel of a set of pixels of array 1033 during the preceding exposure period Timeline 1206 illustrates a timing of readout control pulses applied to image sensor array 1033 A readout control pulse can be applied to image sensor array 1033 after each exposure period EXP|, EXP2, EXP3, EXPN ,, EXPN Readout control pulse 1232 can be applied for reading out a frame of image data exposed during first exposure period EXP, Readout control pulse 1234 can be applied for reading out a frame of image data exposed during second exposure period EXP2, and readout pulse 1236 can be applied for reading out a frame of image data exposed during third exposure period, EXP3 A readout control pulse 1238 can be applied for reading out a frame of image data exposed during exposure period EXPN I and readout control pulse 1240 can be applied for reading out a frame of image data exposed during exposure period EXPN
[00206] After analog voltages corresponding to pixels of image sensor array 1033 are read out and digitized by analog-to-dιgital converter 1037, digitized pixel values corresponding to the voltages can be received by DSP 1070 and converted into a standard or proprietary image format (e g , JPEG) In another embodiment, digitized pixel values captured by image sensor array 1033 can be received into system volatile memory 1080 Terminal 1000 can be adapted so that terminal 1000 can formatize frames of image data For example, terminal 1000 can be adapted so that processor 1060 formats a selected frame of image data in a compressed image file format, e g , JPEG In another embodiment, terminal 1000 can also be adapted so that terminal 1000 formats frames of image data into a video stream format (e g , MJPEG, MPEG-4, or RealVideo™) for transmitting to an external computer or for recording of digital movies
[00207] Terminal 1000 can also be adapted so that processor 1060 can subject to a decode attempt a frame of image data retained in memory 1080 For example, in attempting to decode a 1 D bar code symbol represented in a frame of image data, processor 1060 can execute the following processes First, processor 1060 can launch a scan line in a frame of image data, e g , at a center of a frame, or a coordinate location determined to include a decodable indicia representation Next, processor 1060 can perform a second derivative edge detection to detect edges After completing edge detection, processor 1060 can determine data indicating widths between edges Processor 1060 can then search for start/stop character element sequences, and if found, derive element sequence characters character by character by comparing with a character set table For certain symbologies, processor 1060 can also perform a checksum computation If processor 1060 successfully determines all characters between a start/stop character sequence and successfully calculates a checksum (if applicable), processor 1060 can output a decoded message When outputting a decoded message, processor 1060 can one or more of (a) initiate transfer of the decoded message to an external device, (b) initiate display of a decoded message on a display 1097 of terminal 1000, (c) attach a flag to a buffered decoded message determined by processor 1060, and (d) write the decoded message to an address on long term memory, e g , 1082 and/or 1084 At the time of outputting a decoded message, processor 1060 can send a signal to an acoustic output device 1078 of terminal 1000 to emit a beep
[00208] Times at which terminal 1000, in one embodiment, attempts to decode a decodable indicia represented in a frame of image data are illustrated by periods 4332, 4334, 4336, 4338, and 4340 of timeline 1208 as shown in the timing diagram of Fig 26 Regarding timeline 1208, period 4332 illustrates a period at which terminal 1000 attempts to decode a first frame of image data having associated exposure period EXP|, period 4334 illustrates a period at which terminal 1000 attempts to decode a second frame of image data having second exposure period EXP2 period 4336 illustrates a period at which terminal 1000 attempts to decode a third frame of image data having third exposure period EXP3, period 1338 illustrates a period at which terminal 1000 attempts to decode a frame of image data having an exposure period EXPN , while period 1340 illustrates a period at which terminal 1000 attempts to decode an Nth frame of image data having exposure period EXPN It is seen the "decode time" during which terminal 1000 attempts to decode a frame of image data can vary from frame to frame
[00209] Terminal 1000 can be adapted so that lens assembly 500 has a plurality of lens settings It has been described that the various lens settings of lens assembly 500 can be realized by applying a force to one or more deformable lens elements In one particular example, terminal 1000 can have 7 lens settings At each lens setting, lens assembly 500 and therefore terminal 1000 can have a different plane of optical focus (best focus distance) and a different field of view, typically expressed by the parameter "half FOV" angle The terminal best focus distances at each of the seven lens settings in one particular example can be given as follows Ll =2", L2=5", L3=9", L4= 14", L5=20", L6=27", L7=35", where "L1 -L7" are lens settings " 1 " through "7 " Each different lens setting can have a different associated focal length half FOV angle, and plane of nominal focus In one aspect, terminal 1000 can be adapted to "cycle" between various lens settings according to a predetermined pattern, while a trigger signal remains active In another aspect, terminal 1000 can be adapted while a trigger signal remains active, to change settings between various lens settings that are determined according to an adaptive pattern For example, terminal 1000 can, while trigger signal remains active, change a lens setting of assembly 500 according to a pattern which will enable terminal 1000 to establish an in-focus lens setting without simply testing the degree of focus of each of a succession of lens settings [00210] In another aspect, the timing of the movement of deformable lens element 10 can be coordinated with exposure periods EXP1 , EXP2 EXPN, SO that the lens element 10 is not moved except for times intermediate of the exposure periods Referring to timeline 1210, terminal 1000 can be adapted so that electrical signals are applied to actuator 20 to cause movement of actuator 20 and deformable lens element 10 in such manner deformable lens element 10 is in a moving state only during periods 1432, 1434, 1436, 1438 1440, which are periods intermediate of the exposure periods EXPi, EXP2 EXPN When deformable lens element 10 is controlled according to the timing diagram of FIG 26, it is seen that deformable lens element 10 will be in a static, non-moving state during each exposure period EXP|, EXP2 EXPN
[0021 1 ] An exemplary auto-focusing algorithm is described with reference to the flow diagram of Fig 27 At block 1502 terminal 1000 can determine whether a first frame, / e , the frame having the exposure period EXPi is in-focus A determination of whether a frame is in-focus can include an examination of the "flatness" of a frame of image data Plotting pixel values of a frame in a histogram, an out-of focus frame will have a relatively "flat" distribution of pixel value intensities with a relatively even distribution of intensities over a range of intensities An in-focus frame, on the other hand can be expected to have, relative to an out-of-focus frame, substantial incidences of pixel values at certain intensities and substantially fewer incidences at other intensities If terminal 1000 at block 1502 determines that present frame is in-focus terminal 1000 can proceed to block 1512 to maintain the lens setting at the setting determined to be in-focus and can subject the frame to processing The processing can include, e g , subjecting the frame to an indicia decode attempt or outputting the frame to a display, possibly as a formatted single frame or as an outputted frame of a formatted streaming video image
[00212] If the frame examined at block 1502 is not in-focus, terminal 1000 at block 1506 can examine a frame having a different focus setting than the frame of image data examined at block 1502 By a frame having a "certain lens setting" it is meant that the focus setting of lens assembly 500 was set to the certain setting during the exposure period associated to the frame If terminal 1000 at block 1504 determines that the frame examined at block 1504 is in-focus, terminal 1000 can proceed to block 1512 to maintain the lens assembly 500 at the current setting (the setting yielding to the frame determined to be in-focus) and process a frame or frames exposed with the lens assembly 500 at the determined in-focus setting
[00213] Further referring to the timing diagram of Fig 27, if the frame examined at block 1506 is determined at block 1508 to be not in-focus terminal 1000 can proceed to block 1510 to determine an in-focus setting based on a processing of the first frame examined at block 1502 and the second frame examined at block 1504 Such processing can include evaluating the impact on the flatness of a frame by changing a lens setting (e g , an algorithm may run so that if captured frame becomes more flat [less in-focus] by moving the lens setting from a first setting to a second setting having a farther best focus distance than the first setting, the lens setting is set to a certain setting having a shorter best focus distance than the first setting responsively to the processing) When an in-focus setting has been determined, terminal 1000 sets the lens assembly 500 to the determined in-focus setting and can advance to block 1512 to process a frame(s) having exposure periods coinciding with times at which the lens setting is set to the determined in-focus setting If the frame examined at block 1506 is determined at block 1508 to be in-focus, terminal 1000 can proceed to block 1512 to maintain the lens assembly 500 at the current setting and process a frame or frames exposed with the lens assembly 500 at the determined in-focus setting
[00214] Turing now to the view of Fig 28, a mobile hand held housing 1091 for incorporating and supporting the components of Fig 25 is shown and described The generic form factor of Fig 28 represents the common form factor of a mobile e g , cellular telephone or a portable data collection terminal for use in data collection applications Terminal 1000 can also incorporate a housing in other familiar form factors e g , a digital camera or a camcorder form factor
[00215] As indicated by the displayed menu of display 1097 as shown in FIG 28, terminal 1000 can have a plurality of operator-selectable configurations Each configuration can have a different associated lens setting control algorithm That is, the method by which terminal 1000 controls a lens setting of lens assembly 500 responsively to a trigger signal being made active changes depending on which configuration is selected
[00216] Various operator selectable configurations are summarized in Table D below In configuration 1 , terminal 1000 cycles between various lens settings according to a predetermined pattern Specifically in configuration 1 , terminal 1000 changes a lens setting to a next lens setting after each exposure period, and then decrements the lens setting by 1 after a frame has been captured using the maximum far focus setting (L7) In configuration 2, terminal 1000 responsively to a trigger signal 1202 being made active changes lens settings of terminal 1000 according to an adaptive pattern In Table D, the row entries of configuration 2 illustrate a lens setting change pattern that might be exhibited by terminal 1000 when executing an auto-focus algorithm For frame 1 and frame 2 (having associated exposure periods 1 and 2), the lens setting is advanced However, after frames 1 and 2 are processed a subsequent frame e g , frame 4 corresponding to EXP4 might have a lens setting of L2 if the processing of frames 1 and 2 indicates that setting L2 is an in-focus setting In configuration 3, terminal 1000 does not change the lens setting but rather maintains the lens setting of terminal 1000 at a fixed short focus position Configuration 3 might be selected e g , where it is known that terminal 1000 will be used for fixed position close view indicia decoding In configuration 4, terminal 1000 does not change the lens setting responsively to a trigger signal being maintained in an active state, but rather maintains the lens setting at far focus position Configuration 4 might be useful e g , where terminal 1000 will be used to capture frames for image data corresponding to far field objects In configuration 5, terminal 1000 changes a lens setting adaptively until an in-focus lens setting is determined and then captures a predetermined number of frames using the in-focus setting Configuration 5 might be useful e g , where terminal 1000 is used to capture still image frames of image data From the row data corresponding to configuration 5 in Table D it is seen that terminal 1000 might process frames 1 and 2 to determine an in-focus setting, move the lens setting to the determined in focus setting, capture a plurality of frames at the in-focus setting, process the frames, and then deactivate the trigger signal The plurality of frames captured at the determined in-focus setting might be averaged or otherwise processed for noise reduction Regarding configuration 6, configuration 6 is similar to configuration 1 , except that terminal 1000 when operating according to configuration 6 skips lens assembly settings and maintains the lens setting at each successive setting for a plurality of frames before advancing to a next setting Regarding configuration 7, configuration 7 illustrates operation of terminal 1000 when executing a simplified auto-focus algorithm in which terminal 1000 simply sequentially advances the lens setting for each new frame, tests the degree of focus of each incoming frame, and maintains the frame at the first frame determined to be in-focus Note with respect to the exposure period EXP4, terminal 1000 might advance the lens setting to an un-focused setting while it processes the frame having the exposure period EXP3
Figure imgf000034_0001
[00217] [The following is text substantially as presented in U S Patent Application No 1 1/781 ,901 which includes text substantially as presented in U S Patent Application No 60/875,245]
[00218] A focus module containing a boundary element and a focus element The focus element includes a fluid and a deformable membrane, with the fluid being entrapped between the boundary element and the deformable membrane The focus module also includes
[00219] a pressure element, which is capable of deforming the focus element by pressing on the deformable membrane in the direction of the boundary element
[00220] The present invention provides a focus module for use in a fluid lens that in particular has few moving parts and does not require the presence of multiple chambers or reservoirs for the fluid component of the lens
[00221 ] More particularly, the present invention is directed to a focus module which may include the following elements
1 ) a boundary element, which may be rigid (such as glass or plastic) or deformable (such as elastomer),
2) a spacer element, interposed between the boundary element and focus element, 3) a focus element, deformable in at least one dimension (such as a fluid or elastomer),
4) a pressure element, which transmits force from the deforming element to the focus element,
5) a deforming or actuator element (such as artificial muscle or electrically actuated polymer) to act upon the focus element,
6) a conductor element for conducting an electrical signal or stimulus to the deforming element,
7) a housing element to provide a physical housing or anchor for the assembly, and
8) a power source, generally located external to the focus module, for powering the conductor element
[00222] As will be explained further herein, not all of these elements are required for an operable focus module For example, the deforming element may also function as the spacer element, the spacer element may be omitted, as when the lens is provided by use of a unitary fluid-filled element as discussed hereinbelow, the pressure element may be omitted, with the deforming element acting directly on the focus element, and the housing element is essentially a container into which the other elements may be placed, or in which they may be assembled, and whose function may be provided by other structural elements in the apparatus or device in which the focus module is to function
[00223] The boundary element may be rigid, such as glass or plastic, or deformable, such as an elastomer When it is desired that the boundary element not undergo any deformation as a result of deforming force being applied to the focus element, it is sufficient if the elasticity of the boundary element is such that the boundary element will not deform in response to the force or energy that will be communicated to it when the focus element is at maximum deformation For example, if the focus module includes a boundary element, spacer element, and focus element, with the focus element comprising a fluid and a deformable membrane where the fluid is entrapped between the boundary element and the membrane, and, a pressure element is used to deform the focus element by exerting pressure on the fluid, whether by pressing on the membrane in the direction of the boundary element or by decreasing the diameter of the fluid space between the boundary element and the membrane (for example, by annular tightening), if it is desired that the boundary element not deform, then it should be sufficiently rigid to remain planar when the pressure element is exerting maximum pressure on the fluid In other words, when it is desired that the boundary element not deform during operation of the focus module, it is necessary only that the boundary element not deform under such conditions, and not that it be completely rigid or incapable or deforming
[00224] As stated, glass may be used, and a variety of optical glass materials are commercially available, including, for example, Corning® EAGLE2000™ Display Grade glass, available from Corning Display Technologies, Corning, New York USA, and N-BK.7 glass, available from Schott North America lnc , Duryea, Pennsylvania USA The boundary element may be any suitable thickness, including from about 0 I mm to about I mm, for example, 0 2, 0 3, or 0 4 mm [00225] The spacer element may be any of a variety of materials, including metal, plastic, and ceramic, depending on its desired functionality When that functionality is limited to spacing the boundary element from the focus element it may be any material that is compatible with the other materials it will contact, including the focus fluid, such as stainless steel When it is also desired to provide a seal between itself and the boundary element and/or the focus element, the spacer may be a two-sided tape When it is desired to serve as the deforming or actuator element it may be an artificial muscle or electro-actuated polymer as discussed further herein When the spacer element is desired to both seal to the boundary and/or focus elements and serve as the deforming or actuator element, it may be a double sided tape that additionally provides a deforming or actuator function in response to electrical stimuli, for example, a 3M™ VHB™ tape such as Double Coated Acrylic Tape 4910, available from a number of distributors, including Hillas Packaging, Inc , Fort Worth, Texas, USA
[00226] In order to facilitate filling of the fluid chamber with focus fluid, a gap or port may be present in the spacer element, shown in Fig 29 as element 2a After the fluid chamber has been filled with focus fluid, this gap or port may be sealed by any means that will both prevent fluid from escaping the chamber, and will withstand the pressure subsequently exerted by the focus fluid as in response to actuation of the deforming element For example, an epoxy adhesive may be used to provide this seal
[00227] The focus element may be a single component, such as a fluid-filled-filled elastomer, polymer, or plastic, for example, a transparent oil-filled elastomer material which has an elastic memory Alternatively, the focus element may be two or more components, with a focus fluid (such as water or oil) entrapped or sandwiched between the boundary element and a deformable focus membrane, in which configuration the focus fluid and the focus membrane would together comprise the focus element When a membrane is used, suitable materials would include polydimethylsiloxane, or PDMS, such as Sylgard® 184 silicone elastomer, available as a kit from Dow Corning Corporation, Midland, Michigan, USA The membrane thickness may be selected based on factors such as the size of the focus module in question and may be, for example, from about 0 1 to about 1 mm, for example, 0 2, 0 3, or 0 4 mm
[00228] When a focus fluid is used, its properties should be selected for compatibility with the other materials, stability under use, tolerance for the anticipated temperatures at which it will be used, and similar factors Optical fluids and optical grade oils, such as optical grade mineral oils, may be used One suitable optical fluid is Type A immersion oil, available from Cargille-Sacher Laboratories Inc , Cedar Grove, New Jersey, USA Another suitable fluid is the Santovac® polyphenyl ether-based optical fluid SL-5267, available from Arch Technology Holding LLC , St, Charles, Missouri, USA Water may also be used, such as de-ionized water
[00229] As previously noted, the boundary element and focus element must be optically clear, at least in that portion thereof used to transmit image information Thus, while the entirety of each such element would normally be optically clear in order to simplify manufacture and assembly, it is also possible for at least a part of an outer ring portion of either or both of the boundary element and focus element to be translucent or opaque, surrounding an inner portion that is optically clear
[00230] When it is desired to minimize loss of light transmitted through the focus module due to reflection loss, the materials selected for the boundary element and focus element should have similar indices of refraction For example, where the focus module includes a glass boundary element, a focus fluid, and a focus membrane, one should consider the difference in indices of refraction both of the focus fluid compared to the boundary element, and of the focus fluid compared to the focus membrane The greater the difference in indices, the more light will be loss to reflection as it attempts to pass from one material (such as glass) to the next (such as an immersion oil) Conversely, the closer the indices, the less light will be lost to reflection In this context the indices will ideally identical, and preferably will be within about +/- 0 001 to 0 01 , such as about 0 002 However, there may be situations where differences in the indices of refraction may be advantageous, such as to reduce certain types of aberrations
[00231 ] It is also possible to vary the thickness of the focus membrane over the deformation area, which would result in a structure having aspheric attributes while retaining the variability otherwise enabled by the present invention
[00232] Choosing a focus fluid with a relatively high index of refraction will reduce the amount of deformation needed to obtain a given change in focal distance For example, a suitable index of refraction would be in the range of from about 1 3 or about 1 5 to about 1 6 or about 1 7, such as an index of about 1 5 or about 1 6
[00233] The pressure element may similarly be any of a variety of materials, including metal, plastic, and ceramic The choice of material will depend on compatibility with other materials and on the desired response to force exerted by the deforming element If it is desired that the pressure element not itself deform, it should be an inelastic material such as metal, ceramic, or plastic If, however, it is desired or necessary that the pressure element change its shape or configuration in response to the deforming element, it should be composed of a deformable material such as an elastomer
[00234] The deforming element is the component that responds to a control signal by varying the force applied to the focus element, either indirectly (such as through the pressure element) or directly Particularly suitable for use as the deforming element are electroactive or electroconducting polymer actuators One example is Electroactive Polymer Artificial Muscle and/or the Universal Muscle Actuator™ platform, available through Artificial Muscle, lnc , of Menlo Park, California, USA Another example is conducting polymer actuator available from EA MEX Corporation of Osaka, Japan
[00235] Where the deforming element is an artificial muscle or electro-actuated polymer, it may be possible to provide the deforming element as two or more layers, analogous to layers of muscle fiber Moreover, where each layer deforms in a particular direction in response to electrical stimuli, this effect may be used to select a given direction of motion for the overall layered assembly In this way, and taking for example a deforming element in which layers of artificial muscle of polymer have been assembled into the shape of a rectangular solid as shown in Fig 44, the rectangular solid may then curl up as shown in Fig 45, extend laterally as shown in Fig 46, or curl down as shown in Fig 47, or even twist, in response to electrical stimuli, though use of a non-elastic structure to constrain one or more directions of motion, or to force the motion in a particular manner, may be required Figs 45 and 47 depict non-uniform curvature of the rectangular solid, which could be accomplished by constraining a portion of the rectangular solid such as by a frame or other external structure (not shown), by anchoring or fixing a portion of the solid to an inelastic element, or by appropriate construction or selection of the layers which comprise the solid Alternatively, the rectangular solid may exhibit a constant radius of curvature along its length, for example, the curve formed by a longer side may represent an arc along the circumference of a circle Where multiple electrical circuits are present in the deforming element, the electrical stimuli may include applying voltage to less than all of the circuits, and/or applying voltage of opposite polarities to those circuits
[00236] These changes in shape may further be accomplished by layering as described, with each layer, or combinations of layers, having its or their own electrical control circuit, or, the deforming element may be constrained by a frame or other structure that limits its motion in one or more direction, thereby forcing movement in the desired direction Similar effects may be accomplished by making the layers of unequal dimension, for example, in a two-layer structure, if one layer is longer than the other in a particular dimension, then actuation of the layers will generally produce curling in the direction of the shorter layer This mode of action may be better understood by reference to deforming element 5 as shown in Figs 29, 30, and 36 In Fig 36, for example, the finger or tab-like elements 5a may function by containing two or more layers of polymer, with the layers closer to the focus membrane being shorter than those closer to the boundary element When deforming element 5 is activated, this difference in the size or dimensions of the layers will cause each finger element 5a to curl or flex towards the pressure element, forcing it in the direction of the focus membrane, and this motion will in turn deform the focus membrane into the shape of a convex lens Alternatively, a non- deforming layer may be included in the structure, in which case the deforming layer or layers will generally curl or move towards or in the direction of the non-deforming layer
[00237] Figs 48 and 49 demonstrate a bi-convex electro-actuated polymer membrane lens In this embodiment, when both surfaces are deformable membranes, it is possible to construct a bi-convex lens Moreover, the two surfaces of the membranes may have different surface curvatures due to different membrane diameters Differences in the material, and thickness, of the membrane can also be used to create different surface shapes
[00238] Fig 50 shows a multiple deformable membrane lens assembly, and it should be noted that a zoom lens can be achieved using two (or more) lenses actuated by electro-actuated polymer and other fixed elements
[00239] Figs 51 and 52 show that by placing a conventional lens in an electro-actuated polymer mechanism, a variable location lens element can be made for compact auto-focus or zoom applications, with additional fixed elements
[00240] As noted, the deforming element may act directly on the focus element, as by being in direct contact with it Alternatively, force generated by activation of the deforming element may be transmitted to the focus element through one or more intermediary devices or elements As an example, a pressure element may be adjacent to and in contact with the focus element, and the deforming element may press on the pressure element, which transmits that force through to the focus element In one embodiment the pressure element may be in the shape of an annulus, or doughnut, and may be in direct or indirect contact with an outer ring portion of the focus element
[00241 ] The conductor element communicates the control signal to the deforming element Where the deforming element responds to electric signals, as in the case of electro-actuated polymers, it generally serves as a conductor for conducting electrical motive power from the power source to the deforming element It should therefore be conductive, preferably highly conductive, at least in relevant portions, and may comprise a conductive material, including a conductive metal such as copper, a conductive plastic, or an elastomer that has been treated or doped, such as with carbon, to render it conductive Specific examples include use of flexible printed circuits (FPC) and sputtering or evaporating a conductive metal onto the surface of the deforming element
[00242] As depicted in Fig 29, the conductor element comprises two components, one on either side of the deforming element, with each component having an electrical contact access 6c for connection to a power source In this embodiment the deforming element will be uniformly activated or deactivated in response to the presence or absence of an electrical signal, and the convex meniscus formed by the focus element will be symmetrical
[00243] However, it is also contemplated that the conductor element may include a plurality of circuits enabling selective actuation of one or more portions of the deforming element, thereby allowing tunable steering of the focus element by enabling the convex meniscus to be selectively asymmetric For example, and with reference to Fig 36, the deforming element is shown as a single conductive element Alternatively, the deforming element could be constructed, such as by the use of insulating materials between flex circuits, such that each finger (also shown as elements 5a in Fig 30), or combinations thereof, provide separate and independently energizable circuits
[00244] By choosing which circuits to energize, and how much control signal to apply, the system could control not only the formation and magnitude of the meniscus, but also its tilt In this context, tilt refers to the possible combinations of pitch and yaw that may be used to configure the meniscus to have shapes other than symmetric to an axis normal to the boundary element and centered in the fluid chamber A simple example is shown in Fig 37, in which focus fluid 3b has been further represented as having meniscus element 3c, shown as having a non-symmetric shape in response to selective application of control signals to a multi-circuit conductor element (not shown)
[00245] The conductor element is connected to a power source selected to deliver the range and polarity of voltage necessary to drive the deforming element through its full intended range of motion
[00246] The figures may be referenced to provide further context for the above discussion, it being understood that they merely present one specific construct of the focus module as a convenience for purposes of the this discussion
[00247] In particular, Fig 29 provides an exploded view of one embodiment of the focus module In this embodiment, spacer element 2 creates a spaced-apart relationship between boundary element I and focus element 3 Pressure element 4 rests against focus element 3, and is acted on by deforming element 5, which is itself acted on by conductor element 6 In the embodiment shown, conductor element 6 comprises two sub- elements 6a and 6b, which are conductive elements used to transmit electrical control signals to deforming element 5 Element 6c is an electric contact access for conductor element 6 A complementary electric contact access is present on element 6a, but is not visible in Fig 29 Element 7 is a housing element, and serves to provide a physical environment for the focus module
[00248] Figs 30 and 31 show the focus module embodiment of Fig 29 in assembled form, in which housing element 7, electrical contact element 6c, deforming element 5, and pressure element 4 are most visible In the perspective of Fig 30 the assembled focus module is viewed from the right side of Fig 29, with the boundary element closest to the viewer, and in Fig 31 the assembled focus module is viewed from the left side of Fig 29
[00249] The overall size of the assembled focus module is not critical and may be varied depending on the size of the available components, the device into which it will be placed or assembled, and the needs of the user In general, the focus module, which is generally cylindrical as shown in Figs 30 and 31 , will have a diameter d of from about 5, 7, or 9 mm to as large as about 1 1 , 13, 15, or 20 mm The size may be selected in order to maximize or achieve drop-in compatibility with existing devices, for example, in camera-enabled cellular telephones, a diameter of about 9, 9 5, or 10 mm may be preferred
[00250] For purposes of example, Figs 32 and 34 each depict an assembly including a boundary element 1 , focus fluid 3b, focus membrane 3a, and deforming element 5 In Figs 32 and 34, minimal pressure is being applied to focus fluid 3b, and focus membrane 3a is correspondingly planar In Figs 33 and 35, pressure is being applied by deforming element 5 to focus fluid 3b, and as a result focus membrane is forming a convex lens or meniscus In Fig 32 the pressure applied by deforming element 5 is exerted in a direction substantially normal to the plane represented by focus membrane 3a and in the direction of boundary element 1 , reducing the height of the chamber containing the focus fluid around its circumference and thereby forcing fluid from the periphery of the fluid chamber into the middle, this effect produces the convex meniscus visible in Fig 33
[00251 ] As previously noted, the deforming element may act on the focus element directly or indirectly Also as previously indicated, direct action may involve placing the deforming element directly adjacent the focus element, for example, directly contacting the focus membrane when the focus element is comprised of a focus membrane and a focus fluid entrapped between the focus membrane and the boundary element, with a spacer element defining the wall of a chamber holding the focus fluid In an alternative embodiment, the deforming element may itself comprise the wall separating the boundary element and the focus membrane This embodiment is shown in Fig 34, where deforming element 5 is also serving as the wall of the cylindrical chamber containing the focus fluid 3b, that chamber having a 'top' wall formed by the focus membrane 3a and a 'bottom' wall formed by the boundary element 1
[00252] In this embodiment the pressure exerted by deforming/spacer element 5 is exerted in a direction substantially parallel to the plane represented by focus membrane 3a and in the direction of the middle of the fluid chamber Depending on the characteristics of the material used for the deforming element, this pressure may not be accompanied by any change in height of the fluid chamber, and the deforming element may simply increase its thickness radially Alternatively, the extension of the deforming element radially inward may be accompanied by a decrease in height or thickness of the deforming element inward as shown in Fig 35, effectively drawing focus membrane 3a and boundary element 1 towards each other and contributing to the formation of the convex meniscus, not only is the inward radial movement of the deforming element forcing the focus fluid to occupy a smaller-diameter cylinder, but the drawing-together of the focus membrane and boundary element are also reducing the height of that cylinder
[00253] More generally, and with reference to Fig 38, the focus module may include a cylinder 4100 having at least a top surface 4101 , a bottom surface 4102, an outer wall 4103, a fluid interior volume 4104, the cylinder having diameter d and height h When the actuator element is external to this structure it will exert pressure on at least one of the top surface, bottom surface, or outer wall in order to reduce one or both of height h and diameter d Because the contents of the fluid interior volume are incompressible, this reduction in height and/or diameter must be offset by a corresponding expansion of the volume in some direction which, in the case of the focus module, will involve deformation of one or both of top surface 4101 and bottom surface 4102 Figs 39 and 40 provide a simplified, straight side-on view of this effect In particular Fig 39 provides an illustration of deformation caused by a reduction in height, with the cylinder now having the same diameter d but height h' < h, and Fig 40 provides an illustration of a deformation caused by a reduction in diameter, with the cylinder having the same height h but diameter d' < d, neither illustration is necessarily to scale In both of these illustrations the deformation and corresponding change in one dimension if offset by a convex distortion of the top surface 4101 In these embodiments the deforming or actuator element may be exerting pressure on the fluid interior as shown in Figs 29-35 Of course, both the diameter and the height may be changed at the same time, and this could be used to produce a relatively larger meniscus, and/or to decrease the time required to form the meniscus
[00254] Alternatively, the deforming or actuator element may comprise part or all of outer wall 4103, as show in Figs 41 and 42 Here the cylinder is shown in cross-section to illustrate the annular nature of deforming element 5 In Fig 41 the upper deformable surface (not shown) will be planar, while in Fig 42 the deforming element has responded to actuation by contracting in the vertical or "h" dimension and extending or elongating in the horizontal or "d" dimension In Fig 42 the effect is shown with the deforming element drawing the upper and lower surfaces together uniformly over their entire surface area, which requires that the exterior circumference of one or both be vertically moveable or slideable rather than fixed or anchored (In this discussion, directional references such as "horizontal," "vertical," and the like are generally used in the relative rather than absolute sense, with, for example, vertical referring to the direction defined by a line normal to the top and bottom surfaces when both are planar, and horizontal referring to the direction defined by a line parallel to those surfaces when both are planar) However, it is also contemplated that at least one surface or surface edge will be anchored or fixed, which will result in a different effect when the deforming element changes its dimensions For example, and with reference to Fig 42, if the top surface is deformable while the bottom surface is rigid, and the outer circumference of the cylinder is constrained such as by being contained within a ring of metal, ceramic, or other rigid material, movement of the deforming material to contract or compress in the vertical dimension and to extend or elongate in the horizontal dimension will not be uniform and symmetrical, but may, for example, result in a funnel-like shape as shown in Fig 43
[00255] It should be noted that it is equally possible to construct the focus module to produce a concave lens For example, the pressure ring and deforming element could be positioned under the focus membrane, between that membrane and the spacer element, and activation of the deforming element could increase, rather than decrease, the height of the fluid chamber around its circumference or periphery The same effect would be achieved if the deforming element also served as the spacer element, as discussed elsewhere herein, with the pressure element positioned between the deforming element and the focus membrane The pressure element need not be present, in which case the deforming element would act directly on the focus membrane
[00256] Another concave lens embodiment may be considered in reference to a particular method of preparing and filling the fluid chamber First, one or more boundary elements, such as glass plates, are placed in recesses provided in a support structure such as a metal plate Spacer elements, such as double-sided tape, are then placed on each glass plate Next, a sheet or layer of PDMS is placed over the glass plate-spacer element assemblies, this sheet may, for example, be prepared by spin-coating the PDMS to a desired thickness using known techniques The resulting assemblies of glass plate boundary element, spacer element, and PDMS membrane element are then placed under vacuum, focus fluid is added, and the vacuum is released to draw the focus fluid into the fluid chambers If this filling process is stopped before the fluid chambers are completely filled, the initial shape of the focus membrane will be concave Depending on the degree of concavity selected, and the parameters chosen for the rest of the focus module, the resulting module may function only by varying the degree of concavity of the focus element, or may be capable of deforming the membrane from a concave state to a flat state, and even of deforming it beyond a flat state to a convex state
[00257] The deforming element has an active and passive state, depending on whether or not a control signal is being applied, and has a continuous transition between the two states, preferably in linear response to the strength of the control signal Using "deactivated" to describe the state of the deforming element when the control signal is at zero or minimal input, and "activated" to describe the state of the deforming element when the control signal is applied, the system may be configured either such that the deactivated state is when maximum force is being applied to the focus element, or when minimal force is being applied
[00258] Therefore, Figs 32 and 34 may be characterized as representing deactivated states, the system being configured such that the deforming element is communicating minimum force to the focus fluid when no control signal is being applied, and Figs 33 and 35 may represent activated states, in which a control signal is being applied to energize the deforming element However, it is possible also configure the system in the opposite sense, so that Figs 32 and 34 represent that state of the system when the control signal is being applied, and Figs 33 and 35 represent its state when the control signal is at zero or minimal strength In more common terms, the deforming element may either be relaxed (as in Figs 32 and 34) when the power is off and stretched or expanded (as in Figs 33 and 35) when power is on, or vice versa This generally translates into what the desired 'resting' state of the focus module should be When the focus membrane is planar the focus is set to infinity, and when it is convex the focus is at a finite distance, such as from about 5 mm to about 500 mm, including all points there between, such as about 50, 100, 150, or 200 mm Configuring this aspect of the system may therefore depend on whether the user wishes the 'normal' or 'resting' state to be focused on infinity, or closer in
[00259] While the foregoing discussion has been presented in the context of a focus element comprised of a focus fluid and focus membrane, it is also applicable to the alternative embodiment where the focus element is unitary, as in the case of a fluιd-filled/oιl-filled elastomer In this embodiment, the outer surface of the focus elastomer provides the function of the focus membrane, and the interior of the focus elastomer provides the function of the focus fluid
[00260] The deforming element and related assembly of the present invention may also be used to control motion of a conventional, rather than fluid, lens It is further possible to combine the focus module of the present invention with one or more conventional or fluid/adaptive lenses, and/or with one or more other focus modules In this way further functionalities such as zoom or auto zoom may be realized These and related concepts are further described in the Appendix being filed contemporaneously with this disclosure
[00261 ] The focus module may be used in a wide variety of devices having or using imaging capabilities, including data collection devices such as bar code scanners, portable data terminals (PDTs), portable data assistants (PDAs), camera-enabled cellular telephones, still picture cameras, moving picture cameras, and the like, further including both fixed-mount and portable devices The focus module may be used in any size and type of such device, but due to its small size and minimal use of moving parts, it is especially well-suited for devices where minimal use of space is particularly desirable, and/or where ruggedization is desired against shock, vibration, and other environmental influences that could affect the operability and/or effective lifespan of components having more and/or more delicate moving parts
[00262] As one particular but non-limiting example, the present invention may be applied to apparatus and methods useful for imaging, capturing, decoding and utilizing information represented by encoded indicia such as bar codes (for example, 1 D bar codes, 2D bar codes, and stacked bar codes), optically recognizable characters (for example printed, typed, or handwritten alphanumeric symbols, punctuation, and other OCR symbols having a predefined meaning), as well as selected graphical images such as icons, logos, and pictographs The apparatus and methods involve the use of one or more focus modules with data readers such as hand held bar code readers to accomplish such tasks as imaging barcodes and other optically readable information, including focusing on images of interest, and improving image quality by removing artifacts such as jitter introduced by a user who is manually operating a reader of the invention
[00263] The device which bas been described and which has been termed a liquid lens of variable focal length has many other applications It may be employed, for example, as an electrostatic voltmeter, as the alteration in the divergence or convergence of a translated beam is a function of the intensity of the impressed field The device may be employed in connection with suitable apparatus for the transmission of audible or other signals over a beam of light When the device is employed in connection with transmission of audible signs it may be said to modulate the beam of light at audible frequencies, and where such an expression is used in the claims it should be so interpreted It is also suited for use in sound-recording on motion picture film
[00264] Although the focus module of the present invention is generally driven by what may be characterised as an electric potential, the electrical signals or stimuli used to control the focus module may be characterized in terms of voltages (electric potentials, or electric potential differences), as well as other electrical parameters, such as electric current or electric charge (the time integral of electric current) For the purposes of the present disclosure, the focus module, and in particular the deforming element (as acted upon through the conductor element), may be controlled by an applied electrical signal for driving any type of fluid (or reconfigurable) lens that responds to the applied signal by exhibiting adjustable behavior based on the interaction of light with two or more fluids (or a fluid and vacuum) having differing optical indices
[00265] We now describe apparatus and methods of operation that embody various features and aspects of the invention, in the form of readers having the capability to obtain images, and to detect, analyze, and decode such images In particular, the readers of the invention can in some embodiments be hand held, portable apparatus that can image encoded indicia, such as bar codes of a variety of types ( I D, 2D, stacked I D, and other bar codes), and symbols such as handwritten, printed, and typed characters (for example using optical character recognition methods), as well as imaging surfaces or objects that are amenable to being identified using optical illumination
[00266] Fig 53 is a diagram showing a reader 900, such as a bar code scanner, embodying features of the invention The reader 900 comprises various optical components and components of hardware and software for controlling the operation of the reader 900 and for analyzing an image acquired by the reader 900 Fig 54 is a diagram showing the control circuitry of the reader of Fig 53 in greater detail In Fig 53, a case 902 is shown in dotted schematic outline The case 902 can in principle be any convenient enclosure or frame for supporting the various components in suitable mutual orientation, and in some embodiments is a case adapted to be held in a hand of a user, as described in greater detail hereinbelow in conjunction with Figs 51 and 52 The reader 900 comprises sources of illumination 904, 906 that can be operated in various circumstances to illuminate a target and to provide an aiming signal The illumination source 904 is in general a source comprising one or more light sources such as lamps or LEDs that provide illumination at a convenient wavelength, such as red or green illumination, for illuminating a target whose image is to be acquired The aimer source 906 in some embodiments is a second LED that is used to back illuminate a slit that creates an aiming signal This slit is then imaged onto the target 914 with an appropriate imaging optics Alternately the aimer source (LED) 906 operates at a different wavelength from the illumination source 904 (for example, the illumination source may be red for illumination and the aiming source may be green for the aiming signal) so that it is easily distinguished therefrom The aimer source 906 is used by an operator of the reader 900 to ascertain what the reader is aimed at Optics 908 are provided for distributing the illumination from illumination source 904 in a pattern calculated to illuminate a target 914 In a preferred embodiment the target is illuminated optimally In one embodiment a collimation lens 910 and a diffractive element 912 are optionally provided to collimate the light from a laser aimer source 906, and to spread or diffract the light from the aimer source 906 in a predefined pattern, respectively As can be seen in Fig 53, an object 914 to be imaged is situated on an object plane 916 located at a distance q l from the reader 900 The object 914 is for example a bar code affixed to a surface, namely the object plane 916 For purposes of discussion, there is also shown in Fig 53 a second object plane 916' located at a greater distance q2 from the reader 900, and having thereon an object 914' (which can also be a bar code) The surface 916, 916' is preferably illuminated, either by light from the illumination source 904, or by ambient light, or a combination thereof As can be seen in Fig 53, the aimer 906, the collimation lens 910 and the diffractive element 912 in combination provide a locator pattern 918, comprising 5 elements 918a-918e in Fig 53, that identify for a user where the reader 900 is aimed, so that a desired target can be made to fall within the aiming area of the reader 900 Light reflected from the target (or alternatively, light generated at the target) is captured by the reader using a lens 920, which in some embodiments comprises a fluid lens and possibly one or more fixed lenses, and is conveyed via the fluid lens to an imager 922 The imager 922 in various embodiments is a 1 D or 2D semiconductor array sensor, constructed using any convenient processing technology, such as a CMOS sensor, a CCD sensor, or the like The imager 922 converts the optical signals that it receives into electrical signals that represent individual pixels of the total image, or frame, or a portion thereof In various embodiments, the imager can be any of a color CCD imager, and a color CMOS imager
[00267] The reader 900 also includes various hardware components, shown in a single control element 930 for controlling and for acquiring signals from the reader 900 in Fig 53 The details of control element 930 are shown in Fig 54 An illumination control 931 is provided to control the intensity and timing of illumination provided by the illumination source 904 The illumination control 931 is in electrical communication with illumination source 904 by way of a cable 905 comprising conductors An aimer control 932 is provided to control the intensity, color and timing of illumination provided by the aimer source 906 The aimer control 932 is in electrical communication with aimer source 906 by way of a cable 907 comprising conductors An imager control 934 is provided to control the timing and operation of the imager 922, for example by providing clocking signals to operate the image, reset signals, start and stop signals for capturing illumination, and synchronization signals for providing electrical output as data indicative of the intensity of illumination received at any pixel of the imager array 922, which data may be provided as analog or as digital data The imager control 934 is in electrical communication with imager 922 by way of a cable 923 comprising conductors A lens controller 938 is provided to control the behavior of the fluid lens 920 The lens controller 938 and the fluid lens 920 are in electrical communication by way of a cable 921 comprising conductors
[00268] An analog-to-digital converter 936 is provided for converting analog signals output by the imager 922 to digital signals In some embodiments, a DMA controller 948 is provided to allow direct transfer of digital data to a memory for storage In general, any and all of illumination control 931 , aimer control 932, imager control 934, A/D 936 and DMA 948 are connected to a general purpose programmable computer 942 by way of one or more buses 945, which buses 945 may be serial buses or parallel buses as is considered most convenient and advantageous The general purpose programmable computer 942 comprises the usual components, including a CPU 943 which can in some embodiments be a microprocessor, and memory 944 (for example semiconductor memory such as RAM, ROM, magnetic memory such as disks, or optical memory such as CD-ROM) The general purpose computer can also communicate via one or more buses 947 with a wide variety of input and output devices For example, there can be provided any or all of an output device 946 such as a display, a speaker 948 or other enunciator, devices for inputting commands or data to the computer such as a keyboard 950, a touchpad 952, a microphone 954, and bidirectional devices such as one or more I/O ports 956 which can be hardwired (i e , serial, parallel, USB, firewire and the like) or can be wireless (i e , radio, WiFi, infra-red, and the like) The general purpose programmable computer 942 can also comprise, or can control, indicators 960 such as LEDs for indicating status or other information to a user [00269] As shown in Fig 53, the reader 900 and/or the general purpose computer 942 (as shown in Fig 54) can comprise one or more trigger switches 964 that allow a user to indicate a command or a status to the reader 900 In addition, the entire system is provided with electrical power by the use of one or more of a power supply 970, batteries 972 and a charger 974 Any convenient source of electrical power that can be used to operate the reader 900 and its associated general purpose programmable computer 942 (as shown in Fig 54) is contemplated, including the conventional electrical grid (which can be accessed by connection to a conventional wall plug), and alternative power sources such as emergency generators, solar cells, wind turbines, hydroelectric power, and the like
[00270] A laser bar code scanner can be implemented with a steering lens configuration See Figs 86-88 hereinbelow Rather than using a scanning mirror or motor as presently used in bar code scanners, the scanning motion can be achieved with a steerable fluid lens At the same time the laser spot location of narrowest beam width can also be effected with the same or a different fluid lens Such a scanning system can also be coaxial in nature, where the receive and transmit light beams both focus at the same section of the bar code pattern being scanned This receive optical system is not shown, but these are well known to those in the art A cylindrical or spherical scanning fluid lens may be used depending upon if the designer wishes to develop a single scan line or a raster scan line It is also envisioned that it may be possible to develop a fluid element that scans only, without having optical power Such systems are also contemplated
[00271 ] As may be seen from Fig 53, the distance at which the reader of the invention can operate, or equivalently, a focal length of the optical system of the reader, can vary as the distance q from the lens to the object to be imaged vanes The focal length for a specific geometrical situation can be determined from the formula
1/f = l/p + 1/q
in which f is the focal length of a lens, p is the distance from the lens to a surface at which a desired image is observed (such as an imaging sensor or a photographic film), and q is a distance between the lens and the object being observed
[00272] Consider the two objects situated at a nearer distance q l and a farther distance q2 from the reader lens (e g , q2 > q l ) In a system that is less expensive and more convenient to construct, the distance p (from the lens 920 to the imaging sensor 922) is fixed One can image objects lying at the distance q l from the lens with a focal length given by 1/fl = l /p + 1 /q l , and one can image objects lying at the distance q2 from the lens with a focal length given by 1 /f2 = l/p + ]/q2 Since q2 > ql , and p is constant, we have f 1 < f2 In particular, for a reader comprising a fluid lens that can provide a minimum focal length of fi and a maximum focal length of f2, for a fixed value of p, one would have the ability to observe in proper focus objects at distances ranging at least from q l to q2, without consideration for issues such as depth of field at a particular focal length setting of the lens By way of example, q l might be a short distance such as 4 inches (approximately 10 cm) so that one can image a target object having much detail (such as a high density bar code) with recovery or decoding of all of the detail present in the object On the other hand, q2 might be a longer distance, such as 12 inches (approximately 30 cm) or more, whereby a reader can image an object at longer distance with lesser density (e g , fewer pixels of resolution per unit of length or area observed at the target object) Accordingly, a reader of the invention comprising a particular imaging sensor can be configured to perform at either extreme of high density/short distance or of low density/long distance (or any variant intermediate to the two limits) by the simple expedient of controlling the focal length of the fluid lens such that an object at the intended distance d in the range q2 > d > q l will be imaged correctly
[00273] The lens can be caused to either manually or automatically change its focal length until the best focus is achieved for an object at a given distance away One way to do this is to minimize the so-called blur circle made by a point or object within the field of view This can be done automatically by a microprocessor that vanes the focal length of the lens and measures the size of the blur circle on a CCD or CMOS imager, i e the number of pixels the blur circle fills The focal length at which the blur circle is smallest is the best focus and the lens is held at that position If something in the field of view changes, e g the object gets farther away from the lens, then the microprocessor would detect the change and size of the blur circle and reinitiate the automatic focusing procedure
[00274] The object used to measure the blur circle could be a detail inherently in the field of view, or it could be a superimposed object in the field of view As an example, one could project an IR laser spot into the field (the wavelength of the IR is beyond the sensitivity of the human eye, but not of the CCD or CMOS image sensor) Another means of achieving best focus includes transforming the image into the frequency domain, for example with a Fourier transform, and then adjusting the focal length of the fluid lens to maximize the resulting high frequency components of that transformed image Wavelet transforms of the image can be used in a similar fashion Both the frequency domain and wavelet techniques are simply techniques for achieving best focus via maximization of contrast among the pixels of the CCD or CMOS image sensor These and similar procedures, such as maximizing the intensity difference between adjacent pixels, are known in the art and are commonly used for passive focusing of digital cameras
[00275] Fig 55 is a block diagram of an optical reader showing a general purpose microprocessor system that is useful with various embodiments of the invention Optical reader 4010 includes an illumination assembly 4020 for illuminating a target object T, such as a 1 D or 2D bar code symbol, and an imaging assembly 4030 for receiving an image of object T and generating an electrical output signal indicative of the data optically encoded therein Illumination assembly 4020 may, for example, include an illumination source assembly 4022, together with an illuminating optics assembly 4024, such as one or more lenses, diffusers, wedges, reflectors or a combination of such elements, for directing light from light source 4022 in the direction of a target object T Illumination assembly 4020 may comprise, for example, laser or light emitting diodes (LEDs) such as white LEDs or red LEDs Illumination assembly 4020 may include target illumination and optics for projecting an aiming pattern 4027 on target T Illumination assembly 4020 may be eliminated if ambient light levels are certain to be high enough to allow high quality images of object T to be taken Imaging assembly 4030 may include an image sensor 4032, such as a 1 D or 2D CCD, CMOS, NMOS, PMOS, CI D OR CMD solid state image sensor, together with an imaging optics assembly 1034 for receiving and focusing an image of object T onto image sensor 4032
[00276] The array-based imaging assembly shown in Fig 55 may be replaced by a laser array based scanning assembly comprising at least one laser source, a scanning mechanism, emit and receive optics, at least one photodetector and accompanying signal processing circuitry See Figs 86, 87, and 88 hereinbelow, and the associated description
[00277] A partial frame clock out mode is readily implemented utilizing an image sensor which can be commanded by a control module to clock out partial frames of image data or which is configured with pixels that can be individually addressed Using CMOS fabrication techniques, image sensors are readily made so that electrical signals corresponding to certain pixels of a sensor can be selectively clocked out without clocking out electrical signals corresponding to remaining pixels of the sensor, thereby allowing analysis of only a partial frame of data associated with only a portion of the full imager field of view CMOS image sensors are available from such manufacturers as Symagery, Omni Vision, Sharp, Micron, STMicroelectronics, Kodak, Toshiba, and Mitsubishi A partial frame clock out mode can also be carried out by selectively activating a frame discharge signal during the course of clocking out a frame of image data from a CCD image sensor A/D 1036 and signal processor 1035 may individually or both optionally be integrated with the image sensor 1032 onto a single substrate
[00278] Optical reader 4010 of Fig 55 also includes programmable control circuit (or control module) 1040 which preferably comprises an integrated circuit microprocessor 4042 and an application specific integrated circuit (ASIC 4044) The function of ASIC 4044 could also be provided by a field programmable gate array (FPGA) Processor 4042 and ASIC 4044 are both programmable control devices which are able to receive, to output and to process data in accordance with a stored program stored in memory unit 4045 which may comprise such memory elements as a read/write random access memory or RAM 4046 and an erasable read only memory or EROM 4047 Other memory units that can be used include EPROMs and EEPROMs RAM 4046 typically includes at least one volatile memory device but may include one or more long term non-volatile memory devices Processor 4042 and ASIC 4044 are also both connected to a common bus 4048 through which program data and working data, including address data, may be received and transmitted in either direction to any circuitry that is also connected thereto Processor 4042 and ASIC 4044 differ from one another, however, in how they are made and how they are used The processing module that is configured to extract information encoded by the encoded indicium employs some or all of the capabilities of processor 4042 and ASIC 4044, and comprises the hardware and as necessary, software and or firmware, required to accomplish the extraction task, including as necessary decoding tasks to convert the raw data of the image to the information encoded in the encoded indicium
[00279] More particularly, processor 4042 is preferably a general purpose, off-the-shelf VLSI integrated circuit microprocessor which has overall control of the circuitry of Fig 55, but which devotes most of its time to decoding image data stored in RAM 4046 in accordance with program data stored in EROM 1047 ASIC 4044, on the other hand, is preferably a special purpose VLSI integrated circuit, such as a programmable logic array or gate array that is programmed to devote its time to functions other than decoding image data, and thereby relieves processor 4042 from the burden of performing these functions
[00280] The actual division of labor between processors 4042 and 4044 will naturally depend on the type of off-the-shelf microprocessors that are available, the type of image sensor which is used, the rate at which image data is output by imaging assembly 4030, etc There is nothing in principle, however, that requires that any particular division of labor be made between processors 4042 and 4044, or even that such a division be made at all This is because special purpose processor 4044 may be eliminated entirely if general purpose processor 4042 is fast enough and powerful enough to perform all of the functions contemplated by the present invention It will, therefore, be understood that neither the number of processors used, nor the division of labor there between, is of any fundamental significance for purposes of the present invention
[00281 ] With processor architectures of the type shown in Fig 55, a typical division of labor between processors 4042 and 4044 will be as follows Processor 4042 is preferably devoted primarily to such tasks as decoding image data, once such data has been stored in RAM 4046, recognizing characters represented in stored image data according to an optical character recognition (OCR) scheme, handling menuing options and reprogramming functions, processing commands and data received from control/data input unit 1039 which may comprise such elements as a trigger 1074 and a keyboard 1078 and providing overall system level coordination
[00282] Processor 4044 is preferably devoted primarily to controlling the image acquisition process, the A/D conversion process and the storage of image data, including the ability to access memories 4046 and 4047 via a DMA channel The A/D conversion process can include converting analog signals to digital signals represented as 8-bit (or gray scale) quantities As A/D converter technology improves, digital signals may be represented using more than 8 bits Processor 4044 may also perform many timing and communication operations Processor 4044 may, for example, control the illumination of LEDs 4022, the timing of image sensor 4032 and an analog-to-digιtal (A/D) converter 4036, the transmission and reception of data to and from a processor external to reader 4010, through an RS-232, a network such as an Ethernet or other packet-based communication technology, a serial bus such as USB, and/or a wireless communication link (or other) compatible I/O interface 4037 Processor 4044 may also control the outputting of user perceptible data via an output device 4038, such as a beeper, a good read LED and/or a display monitor which may be provided by a liquid crystal display such as display 4082 Control of output, display and I/O functions may also be shared between processors 4042 and 4044, as suggested by bus driver I/O and output/display devices 4037' and 4038 or may be duplicated, as suggested by microprocessor serial I/O ports 4042A and 4042B and I/O and display devices 4037" and 4038' As explained earlier, the specifics of this division of labor is of no significance to the present invention
[00283] Fig 56 is a flow chart 1 100 showing a process for operating a system having an adjustable focus system comprising feedback, for example a system having components as described in Fig 53 The process begins at step 1 1 10, where a command to capture an image is generated, for example by a user depressing a trigger, or by an automated system issuing a capture image command in response to a specified condition, such as an object being sensed as coming into position for imaging Once an image is captured at step 1 1 10, the image focus is assessed, as indicated at step 1 120 Focus assessment can comprise comparison of the image quality with a specified standard or condition, such as the sharpness of contrast at a perceived edge of a feature in the image, or other standards
[00284] Another procedure for performing an auto focus operation using a flatness metric includes the following steps [00285] 1 Capturing a gray scale image (ι e , capture an image with the hand held reader and digitize the image using at least two bit resolution, or at least 4 discrete values),
[00286] 2 Optionally sampling the gray scale image (i e , extract from the image a line or a series of points, or alternatively, the sampled image can be the captured image if it is a windowed frame comprising image data corresponding to selectively addressed pixels),
[00287] 3 Creating a histogram by plotting number of occurrences of data points having a particular gray scale value, for example using the X axis to represent gray scale values and the Y axis to represent frequency of occurrence,
[00288] 4 Processing the histogram to provide a flatness measurement as output,
[00289] 5 Determining a focus level (or quality of focus) based on the flatness measurement, and
[00290] 6 In the event that the quality of focus as determined from the flatness metric is less than desired, changing the focus and repeating steps 1 through 5
[00291 ] The flatness of an image refers to the uniformity of the distribution of different gray scale values in the histogram A flat distribution is one with little variation in numbers of observations at different gray scale values In general, poorly focused images will be "flatter" than better focused images, i e there will be a relatively even incidence of gray scale values over the range of gray scale values Generally, a histogram for a well focused image has many pixels with high gray scale values, many pixels with low gray scale values, and few pixels in the middle The use of historical information for various types of images, such as bar codes, including information encoded in look up tables, or information provided using the principles of fuzzy logic, is contemplated
[00292] At step 1 130, the outcome of the focus assessment is compared to an acceptable criterion, such as sharpness (or contrast change) of a specified amount over a specified number of pixels Images that are digitized to higher digital resolutions (e g , using a range defined by a larger number of bits) may support more precise determinations of acceptable focus If the result of the assessment of focus is negative, the process proceeds to step 1 140, where the focus of the lens 920 of Fig 53, is modified After adjusting the focus, the operation of the process returns to step 1 1 10, and a new image is captured, and is assessed When an image is captured that is found to have suitable focus, the process moves from step 1 130 to step 1 150, wherein the image with suitable focal properties is processed, and a result is made available to a user or to the instrumentality that commanded the capturing of the image, and/or the result is stored in a memory Optionally, as indicated at step 1 160, the system can be commanded to obtain another image that is to loop back to the step 1 1 10, and to repeat the process again
[00293] Fig 57 is a flow chart showing a process for operating a system having an adjustable focus system that does not comprise feedback At step 4210 a command to capture an image is generated, for example by a user depressing a trigger, or by an automated system issuing a capture image command in response to a specified condition, such as an object being sensed as coming into position for imaging At step 4215, the lens 920 is driven with a first fluid lens control signal corresponding to a first condition, such as a default condition, for example using a voltage applied to the lens 920 that causes the lens 920 to operate by approximation with focal position q l of 7 inches In a preferred embodiment, the applied voltage to focus at 7 inches is zero applied volts Using this focal condition, an image is captured and processed at step 4220 At step 4225, the information retrieved from the captured image is examined to determine if a valid decoding of a bar code has been achieved If the decoding is valid, the information or data represented by the decoded image is reported as indicated at step 4260, and the process stops, as indicated at step 4270 A later command to repeat the process can be given as may be necessary or advantageous
[00294] If at step 4225 it is determined that a good decode has not been achieved, the process continues to step 4230, at which time the fluid lens control signal applied to the lens 920 is adjusted to a first alternative value, for example a voltage that causes the lens 920 to focus by approximation at a distance q2 of 30 cm Using this focal condition, an image is captured and processed at step 4235 At step 4240, the information retrieved from the captured image is examined to determine if a valid decoding of a bar code has been achieved If the decoding is valid, the information or data represented by the decoded image is reported as indicated at step 4260, and the process stops, as indicated at step 4270
[00295] If at step 4240 it is determined that a good decode has not been achieved, the process continues to step 4245, at which time the fluid lens control signal applied to the lens 920 is adjusted to a second alternative value, for example a voltage that causes the lens 920 to focus by approximation at a distance q3 of 100 cm Using this focal condition, an image is captured and processed at step 4250 At step 4255, the information retrieved from the captured image is examined to determine if a valid decoding of a bar code has been achieved If the decoding is valid, the information or data represented by the decoded image is reported as indicated at step 4260, and the process stops, as indicated at step 4270 If a valid decoding of a bar code is still not achieved, the process returns to step 4215, and the process is repeated to try to identify a valid bar code value In other embodiments, after a specified or predetermined number of iterative loops have occurred without a successful outcome, or after a specified or predetermined time elapses, the process can be aborted by a supervisory control device, which in some embodiments can operate according to a computer program Alternately the process may stop if the trigger is released Although the process depicted in Fig 57 uses three discrete conditions to drive the lens 920 in the search for a suitable focus condition, it is possible to use more or fewer than three predefined drive conditions as components of such a process For example, one can define a process in which the focal distance changes by a predefined distance, or a predefined percentage Alternatively, one can define a process in which the adjustment is based upon a quantity determined from the information obtained in assessing whether the captured image is in focus (as described hereinabove) or from the quality of the decoded information (e g , whether the information is completely garbled or incorrectly formatted, or is close to being valid) In general, the distances specified may not be attained to absolute precision (for example, a distance of 30 cm may not be measured to a precision of 30 000 cm but merely to 30 cm to within one tenth of a centimeter), but rather the test is that the lens operates adequately at the distance that is identified In the laboratory, precise distances may be set up for experiments, but in actual use in the field, distances are measured less accurately than in the laboratory [00296] Fluid lenses may have aberrations, such as spherical aberration and/or color aberration In the focus module of the invention, additional lenses, such as positive or negative lenses, can be used in conjunction with the focus module such as lens 920 to correct one or more of spherical, color, or higher order aberrations In some embodiments, the materials of construction of the additional lenses can be chosen so as to compensate for optical imperfections and aberrations introduced by the fluid lens
[00297] Figs 60 and 61 are drawings of hand held readers that embody features of the invention Fig 60 shows a hand held reader 4500 comprising a case having a substantially linear shape The handheld reader 4500 comprises circuitry as has been described with regard to Fig 55, including data processing capability and memory The hand held reader 4500 comprises an input device 4510, such as a key pad, for use by a user, one or more buttons of which may also be used as a trigger 4534 to allow a user to provide a trigger signal The hand held reader 4500 comprises an output device 4512, such as a display, for providing information to a user In some embodiments, the display 4512 comprises a touch screen to allow a user to respond to prompts that are displayed on the display 4512, or to input information or commands using any of icons or graphical symbols, a simulated keypad or keyboard, or through recognition of handwritten information Hand held reader 4500 can also comprise a touch pad or touch screen that can display information as an output and accept information as an input, for example displaying one or more icons to a user, and accepting activation of one of the icons by the user touching the touch pad or touch screen with a finger or with a stylus 4508 The hand held reader 4500 also comprises a bar code image engine 4514 that includes a fluid lens The image engine 4514 acquires images of objects of interest that the hand held reader 4500 is employed to read The fluid lens provides the ability to adjust a focal distance and to adjust an optical axis of the image engine 4514, as is described in more detail herein The hand held reader 4500 also comprises a card reader 4520 that is configured in various embodiments to read cards bearing information encoded on a magnetic strip, such as is found on credit cards, and information encoded in a semiconductor memory, such as found in PC, PCMCIA or smart cards The hand held reader 4500 also comprises a wireless communication device 4530 such as a radio transceiver and/or an infrared transceiver for communication with a remote base station, a computer-based data processing system, a second hand held reader 4500', or a device such as a PDA The hand held reader 4500 also comprises an RFID transceiver 4532 for communicating with an RFID tag As used herein, the term "RFID tag" is intended to denote a radio- frequency identification tag, whether active or passive, and whether operating according to a standard communication protocol or a proprietary communication protocol An RFID transceiver can be programmed to operate according to a wide variety of communication protocols Fig 60 also depicts a card 4540 that in different embodiments includes information encoded on at least one of a magnetic stripe, a semiconductor memory, smart card, and in RFID tag An example of a hand held reader 4500 in which such fluid lens systems can be employed is the PDT 9500, available from Hand Held Products, lnc of Skaneateles Falls, NY In one embodiment, the CMOS image array can be implemented with a Micron image sensor such as the Wide VGA MT9V022 image sensor from Micron Technology, lnc , 8000 South Federal Way, Post Office Box 6, Boise, ID 83707-0006 The MT9V022 image sensor with full frame shutter is described in more detail in the product MT9V099 product flyer available from Micron Technology (www micron com), for example at http //download micron com/pdf/flyers/mt9v022_(mι-0350)_flyer pdf The ICM 105T CMOS progressive imager available from IC Media, 5201 Great America Pkwy, Suite 422, Santa Clara, CA 95054 might also be used The imager is shown at website http //www ic-media com/products/view cfm9product=ICM%2D 105T This imager uses a rolling shutter Although both imagers cited are progressive imagers, as is well known in the art, interleaved imagers will also function properly in these systems
[00298] Fig 61 shows another embodiment of a hand held reader 4550 which comprises components as enumerated with respect to hand held reader 4500, including specifically input 4510, output 4512, image engine and fluid lens 4514, card reader 4520, radio 4530, and RFI D transceiver 4532 The handheld reader 4550 comprises circuitry as has been described with regard to Fig 55, including data processing capability and memory For hand held reader 4550, the case 4560 comprises a "pistol grip" or a portion disposed at an angle, generally approaching 90 degrees, to an optical axis of the imaging engine and fluid lens of the reader 4550 Hand held reader 4550 also comprises a trigger 4534, for example situated on the pistol grip portion of the reader 4550, and located so as to be conveniently operated by a finger of a user Hand held reader 4550 also comprises a cable or cord 4570 for connection by wire to a base station, a computer-based data processing system, or a point of sale apparatus Alternately reader 4550 may communicated to a base station by means of an internal radio (not shown) Examples of readers 4550 in which such fluid lens systems can be employed are the IT 4600 comprising a 2D image sensor array, and the IT 5600 comprising a 1 D image sensor array, all available from Hand Held Products, lnc of Skaneateles Falls, NY
[00299] In some embodiments, the hand held readers 4500 and 1550 are deployed at a fixed location, for example by being removably secured in a mount having an orientation that is controlled, which may be a stationary mount or a mount that can be reoriented Examples of such uses are in a commercial setting, for example at a point of sale, at the entrance or exit to a building such as an office building or a warehouse, or in a government building such as a school or a courthouse The hand held readers of the invention can be used to identify any object that bears an identifier comprising one or more of a bar code, a magnetic stripe, an RFID tag, and a semiconductor memory
[00300] In some embodiments, the hand held reader 4500, 4550 can be configured to operate in either a "decode mode" or a "picture taking" mode The hand held reader 4500, 4550 can be configured so that the decode mode and picture taking mode are user-selectable For example, the reader can be configured to include a graphical user interface (GUI) for example on a touch pad or key pad that is both an input and an output device as depicted in Figs 60 and 61 enabling a user to select between the decode mode and the picture taking mode In one embodiment, the decode mode is selected by clicking on an icon displayed on a display such as display 4512 of Fig 60 whereby the reader is configured with a decode mode as a default Alternatively, the mode of operation (either "decode mode" or "picture taking mode") can be set by a communication from a remote device, or by default upon initial activation of the reader, as part of a power-up sequence Thus, the reader is configured to operate in the decode mode on the next (and subsequent) activation of trigger 4534 to generate a trigger signal In the decode mode, the hand held reader 4500, 4550 in response to the generation of the trigger signal captures an image, decodes the image utilizing one or more bar code decoding algorithms and outputs a decoded out message The decoded out message may be output, e g , to one or more of a memory, a display 4512 or to a remote device, for example by radio communication or by a hardwired communication
[00301 ] In one embodiment, the "picture taking mode" is selected is selected by clicking on icon (which can be a toggle switch) Alternately hand held reader 4500, 4550 is configured in a "picture taking mode" as the default mode Thus, the hand held reader 4500, 4550 is configured to operate in the "picture taking mode" on the next (and subsequent) activation of trigger 4534 to generate a trigger signal The hand held reader 4500, 4550 in response to the generation of the trigger signal captures an image and outputs an image to one or more of a memory, to a display 4512, or to a remote device
[00302] The hand held reader 4500, 4550 can be configured so that when the image capture mode is selected, the hand held reader 4500, 4550 avoids attempting to decode captured images It is understood that in the process of capturing an image for decoding responsively to receipt of a trigger signal, the hand held reader 4500, 4550 may capture a plurality of "test" frames, these may be full frames or only partial frames as discussed above, for use in establishing imaging parameters (e g , exposure, gain, focus, zoom) and may discard frames determined after decode attempts to not contain decodable symbol representations Likewise in the process of capturing an image for image output responsively to receipt of a trigger signal in a picture taking mode, the hand held reader 4500, 4550 may capture test frames, these may be full frames or only partial frames as discussed above, for use in establishing imaging parameters and may also discard images that are determined to be unsuitable for output It is also understood that in the "picture taking mode" the images captured may be archived for later analysis, including decoding of bar codes or other encoded indicia that may be present in the images, for example for use in providing evidence of the condition of a package at the time of shipment from a vendor for insurance purposes (which image may never be decoded if the package arrives safely) Other examples of similar kind can be a photograph of a loaded truck, for example with a license plate, an identifying number or similar indication of which of many possible trucks is the subject of the photograph, optionally including a date and time, and possibly other information that can be stored with the image, such as the identity of the photographer (e g , a name, an employee number, or other personal identifier)
[00303] In an alternative embodiment, the hand held reader 4500, 4550 displays a plurality of icons (at least one for decode mode and one for picture taking mode) whereby activation of an icon both configures the hand held reader 4500, 4550 to operate in the selected operating mode (decoding or picture taking) and results in a trigger signal automatically being generated to commence an image capture/decode (decode mode) or image capture/output image process (picture taking mode) Thus, in the alternative embodiment, the trigger 4534 need not be actuated to commence image capture after an icon is actuated
[00304] Fig 62 is a diagram 4600 of a handheld reader of the invention in communication with a computer In Fig 62, a hand held reader 4550 of the type described hereinabove is connected by way of a cable 4570 to a computer 4610, which in the embodiment depicted is a laptop or portable computer The computer 4610 comprises the customary computer components, including an input 4612, which may include a keyboard, a keypad and a pointing device such as a mouse 4608, an output 4614 for use by a user, such as a display screen, and software 4630 recorded on one or more machine-readable media Examples of software that operate on the computer 4610 are a program 4632 that provides a quick view of the image as "seen" by the image engine and fluids lens in the hand held reader 4550 on the display 4614 of the computer 4610, and a interactive program 4634, for example provided on a machine readable medium, (not shown) that allows a user to control the signal (such as a voltage or electric potential) applied to the fluid lens and to observe that response of the fluid lens thereto, for example as a representation in a graph or as a representation of one or more images read by the reader as the fluid lens control signal is varied In Fig 62, there are also shown a plurality of test targets 1620, 1622, 1624, which in some embodiments are optical test targets conforming to a test target known as the United States Air Force ("USAF") 1951 Target (or 1951 USAF Resolution Target) as shown and described at the web site http //www sinepatterns com/USA FJabels htm, and provided commercially in a variety of forms by SINE PATTERNS LLC, 1653 East Mam Street, Rochester, NY 14609, a manufacturer of the 1951 USAF Target and many other types of targets and visual patterns, as further indicated at the web site http //www sinepatterns com/i_Stdrds htm
[00305] The example depicted in Fig 62 shows a target at each of three distances or positions relative to the hand held reader 4550 In one embodiment, the three targets lie along a single optical axis at discrete, different distances In another embodiment, the three targets 1620, 1622, 1624 lie at the same distance along distinct optical axes relative to hand held reader 1550 In some embodiments, both the distances between the hand held reader 4550 and the targets are distinct, and the optical axes from the hand held reader 4550 to the targets are also distinct Each target 1620, 1622, 1624 presents an object, such as a known test pattern of defined geometry, that the hand held reader 4550 can image By controlling the behavior of the fluid lens in the hand held reader 4550, it is possible to calibrate the operation of the fluid lens by recording the observed control signal (such as a voltage or impressed electric potential) that is required to obtain an acceptable (e g , an image within an acceptable range of image quality or one that can be correctly decoded to retrieve information encoded therein), and preferably optimal, image of the target at each location or position
[00306] Fig 63 is a flow chart 1700 of a calibration process useful for calibrating an apparatus embodying features of the invention In Fig 63, the calibration is initiated, as shown at step 1705, by initializing the system, including performing all power-on-sequence tests to assure that the system components are operating properly At step 1710, a test target bearing a pattern or encoded symbol is positioned at a first test position When in the first test position, the target will in general be at defined distance and orientation relative to the hand held reader comprising a fluid lens At step 1715, the fluid lens control signal (which in some embodiments is a voltage) is adjusted to obtain an acceptable, and preferably an optimal, focus condition for the target At step 1720, the distance and orientation of the target and the fluid lens control signal parameters (for example magnitudes and signs of voltages, timing features of the signal such as pulse duration, transition time and repetition rate) are recorded for future use in a non-volatile memory, for example in a table
[00307] One can iteratively repeat the process steps of locating the target at a new location and orientation, controlling the fluid lens control signal applied to the fluid lens to obtain a satisfactory, and preferably optimal, focus, and recording in a memory the information about the target location and orientation and the fluid lens control signal parameters, so as to provide a more complete and detailed set of calibration parameters The number of iterations is limited only by the amount of time and effort one wishes to expend performing calibration steps, and the amount of memory available for recording the calibration parameters observed In the example presented in Fig 62, a calibration according to the flow diagram of Fig 63 would include performing calibration steps as described by steps 1710, 1715 and 1720 at three distinct positions for the target The information obtained in calibration tests can be used when operating the corresponding imager (or in some instances, another imager of similar type) either by using the calibration information as an initial setting for operation in a closed loop mode as explained in connection with Fig 56, or as fixed operating conditions for discrete points in an open loop operating mode as explained in connection with Fig 57
[00308] Fig 64 is a diagram 1800 showing calibration curves for a plurality of exemplary hand held readers In Fig 64, the horizontal axis 1802 represents a fluid lens control signal parameter, such as voltage, and the vertical axis 1804 represents an optical property of the fluid lens, such as optical power One can also represent other optical properties of a fluid lens that are relevant for its operation, such as focal length, f- number, and deviation from a default optical axis (which default optical axis may be considered to represent zero degrees of elevation or altitude and zero degrees of azimuth) In Fig 64, three curves 1 810, 1 812, 1814 are shown, each curve representing a response (e g , optical power) of a specific fluid lens to an applied fluid lens control signal (e g , voltage) As seen in Fig 64, the curve 1810, representing the behavior of a first fluid lens, reaches an optical power P 1820 at an applied voltage V l 1830 However, other fluid lenses may behave slightly differently, such that a second fluid lens, represented by curve 1812, attains optical power P at an somewhat larger voltage V2 1832, and a third fluid lens, represented by curve 1814, attains optical power P at yet a larger voltage V3 1834 Accordingly, one can extract from the information in Fig 64 a relation between the fluid lens control signal that is to be applied to the first fluid lens and the second fluid lens to attain the same optical power P, for example for operating two hand held readers under substantially similar conditions, or for operating a binocular reader or other device that uses two fluid lenses simultaneously, for example to generate a stereoscopic view of a target At power P, there exists a difference in drive voltage between the first lens and the second lens given by V2-V 1 , where the difference has a magnitude given by the absolute value of V2-V1 and a sign which is positive if V2 exceeds V l in magnitude, negative if V l exceeds V2 in magnitude, and zero if V2 = V l In operation, in order to attain optical power P in both of the first and second fluid lenses, one can provide a fluid lens control signal equal to V l to both the first and second fluid lenses, and a differential signal equal to the signed difference of V2-V 1 to the second fluid lens Alternatively, one could use two power supplies that provide signals V l and V2 to the first and second fluid lenses, respectively As the optical power required for operation of a fluid lens changes, the fluid lens control signal changes, and can be deduced or read from the appropriate curve of Fig 64 Since one in general does not measure the parameters of a fluid lens or other device at all possible values within a range, a curve such as 1 810 can also be obtained by measuring a discrete number of pairs of optical parameter and associated fluid lens control signal, and fitting a curve to the data, or interpolating values between adjacent data points, as may be most convenient to prepare a suitable calibration curve In some instances, only a single calibration point per fluid lens module may be required Rather than creating curves for different fluid lenses, one can measure the same fluid lens at different temperatures Then the appropriate operating point can be determined at the various temperatures Other operating points may be determined by either extrapolation or interpolation, by suitable curve fitting relationships, or by deducing a representation of the behavior in the form of an equation
[00309] Fig 65 is a diagram showing an embodiment of a power supply 1900 suitable for use with hand held readers In general, the first order electrical equivalent circuit for a fluid lens is a simple capacitor In Fig 65, a load 1910 represents in one embodiment a capacitive load to a power supply, generally 1920 Because the load is capacitive, the net power consumed is in general small The power supply 1920 of Fig 65 is one possible embodiment, which is described first at a high level The output of this power supply can be used as input to the commutator shown in Fig 58 comprising switches 4310, 4312, 4314, and 4316 A power source, such as a 6 volt battery 1922, is adequate for operation of the supply The voltage of the power source may be increased using a DC-to-DC converter comprising a switcher IC 1930 having a sensing terminal, a controller for a switch 1940, (such as a transistor) and an inductor 1935 (which may be provided externally to the switcher) The sense terminal in some embodiments is connected to a voltage divider 1955 A rectifier 1945 is used to provide a unipolar output, which includes noise introduced by the switching operation of the switcher The output voltage of the first stage of the power supply can be controlled, and in general will be of the order of tens of volts, for example 60 V DC A filter 1960, such as a low pass RC filter, is provided to eliminate noise, as the capacitive elements represent a small impedance as frequency is increased, and represent a large (substantially infinite) impedance to low frequencies A precision low noise series regulator 1970 is used to control the output voltage for example by controlling a transistor 1972, with a sense input to the series regulator providing a feedback loop through voltage divider 1975 A control 1984 is provided to permit adjustment of the voltage signal applied to the fluid lens, and thereby providing control of a focal distance or plane of focus of the fluid lens 1910 Alternative power supplies that can provide a unipolar output can be used By using a pair of power supplies (e g , one providing a positive voltage and one providing a negative voltage), a single power supply and a suitably biased inverter, or by using a single power supply and dual operational amplifiers, one can provide a pair of outputs that are symmetric relative to ground
[00310] Figs 67-69 are cross-sectional drawings showing an exemplary fluid lens 2100 with a mount comprising an elastomer for a hand held reader Such elastomers are made by Chomeπcs North America, Parker Hannifin Corp , 77 Dragon Court, Woburn, MA 01801 In Fig 67, a fluid lens 21 10 is shown with a solid body 21 12 in the form of a ring, and electrical contacts 21 14, 21 16 disposed on opposite sides thereof In some embodiments, the fluid lens body 21 12 is made of metal, and can also represent one of the contacts 21 14, 21 16, the other contact being insulated from the metal body 21 12 In other embodiments, the body 21 12 is made from, or comprises, a non-conducting substance
[0031 1 ] In Fig 68, the fluid lens body 21 12 is shown mounted in a holder 2120 In one embodiment, the holder 2120 is tubular and has an internally threaded surface 2130 and a partially closed end 2132 having defined therein an aperture of sufficient size not to occlude the optically active portion of the fluid lens The fluid lens body 21 12 is held in place by a threaded retainer ring 2122 that threadedly mates with the internally threaded surface 2130 of the holder 2120 The holder 2120 and retainer ring 2122 are made of an insulating material In some embodiments, an elastomeπc material 2140, 2142 is provided in the form of an "O" ring or an annular washer, so that the fluid lens is supported in a desired orientation, without being subjected to excessive compressive forces or to mechanical disturbances that can be accommodated by the elastomeπc ring 2140, 2142 In some embodiments, a single elastomeπc ring 2140 or 2142 is provided on one side of the fluid lens body 2120 In some embodiments, one clastomeπc ring 2140 is provided on one side of the fluid lens body 2120, and a second elastomeπc ring 2142 is provided on the other side of the fluid lens body Electrical contact with the contacts 21 14 and 21 16 is provided by wires 21 14' and 21 16' that contact the respective contacts and which exit the holder These wires are in intimate electrical contact with the elastomeπc material 2122 and 2140 As needed, wires 21 14' and 21 16' can be insulated Fig 69 shows the elastomeric washer 2140, which in some embodiments can be conductive, in contact with a fluid lens body 21 12 at an electrical contact 21 16 thereof, which fluid lens body 21 12 is supported in a holder 2120 at a partially closed end 2132 thereof A wire 21 16' contacts the conductive elastomeπc washer or ring 2140 and exits the holder 2120 by way of an aperture 2134 defined within the holder 2120 In some embodiments, the wire 21 16' contacts the electrical contact of the fluid lens body, and the elastomeric ring or washer is positioned between the wire 21 16' and the partially closed end 2132 of the holder 2120 In other embodiments, the wire 21 16' is between the elastomer 2140 and the partially closed end 2130 The holder 2120 and threaded ring 2122 can be constructed of any suitable material, and can be non-conductive or conductive as appropriate
[00312] The present invention also deals with the deleterious effects of image smear caused by hand jittering or hand motion in a hand held imager or reader Image smear has been one of the major sources for image quality degradation Image smear and similar degradation mechanisms cause a reduced decode rate in a barcode reading application or a reduced contrast and a blurry image in an image capturing application In some instances, hand jitter or hand motion can cause image degradation that may be severe enough to prevent the image from being processed correctly
[00313] Fig 70 is a diagram illustrating a prior art variable angle prism as disclosed in U S Patent No 6,734,903 to Takeda, et al (hereinafter "the '903 patent") The apparatus disclosed employs two angular velocity sensors, two angular sensors, two actuators and a variable angle prism with a lens system to form an anti-shaking optical system This type of optical system is widely used in hand held video camcorders to correct the hand jittering effect However, such systems suffer from a variety of drawbacks, including 1 higher cost due to many parts, 2 slow response time due to the use of mechanical actuators, 3 lower reliability due to moving parts, 4 the use of a separate auto-focusing electro-mechanical subsystem that further increases the cost and system complexity, and 5 the use of mechanical components that increases the complexity and difficulty of assembly
[00314] The '903 patent describes the operation of the variable angle prism as is expressed in the following 1 1 paragraphs
[00315] A camera shake is a phenomenon in which photographed images move vertically or horizontally while a user is performing photographing by holding a video camera in his or her hands, since the hands or the body of the user slightly moves independently of the user's intention Images thus photographed can give a viewer considerable discomfort when reproduced on a television monitor or the like
[00316] To avoid this camera shake phenomenon, conventional video cameras make use of, e g , a variable angle prism (to be referred to as a "VAP" hereinafter)
[00317] A practical example of an arrangement of a conventional image sensing apparatus including a VAP for camera shake correction will be described below with reference to FIG 29
[00318] In Fig 70, a VAP 2204 is constituted by coupling two glass plates 2204a and 2204b via a bellows- like spring member 2204c and sealing an optically transparent liquid 2204d in the space surrounded by the two glass plates 2204a and 2204b and the spring member 2204c Shafts 2204e and 2204f provided in the glass plates 2204a and 2204b are connected to an actuator 2203 for horizontal driving and an actuator 2208 for vertical driving, respectively Therefore, the glass plate 2204a is rotated horizontally, and the glass plate 2204b is rotated vertical ly
[00319] Note that the VAP 2204 is described in Japanese Patent Laid-Open No 2- 12518 and so a detailed description thereof will be omitted
[00320] A horizontal angular velocity sensor 2201 detects an angular velocity caused by a horizontal motion of the image sensing apparatus resulting from a camera shake or the like A control unit 2202 performs an arithmetic operation for the detection signal from the angular velocity sensor 2201 such that this horizontal motion of the image sensing apparatus is corrected, and detects and supplies an acceleration component to the actuator 2203 This actuator 2203 drives the glass plate 2204a of the VAP 2204 horizontally
[00321 ] The rotational angle of the glass plate 2204a which can be horizontally rotated by the actuator 2203 is detected by an angle sensor 2205 The control unit 2202 performs an arithmetic operation for this detected rotational angle and supplies the result to the actuator 2203
[00322] A vertical angular velocity sensor 2206 detects an angular velocity caused by a vertical motion of the image sensing apparatus resulting from a camera shake or the like A control unit 2207 performs an arithmetic operation for the detection signal from the angular velocity sensor 2206 such that this vertical motion of the image sensing apparatus is corrected, and detects and supplies an acceleration component to the actuator 2208 This actuator 2208 drives the glass plate 2204b of the VAP 2204 vertically
[00323] The rotational angle of the glass plate 2204b which can be vertically rotated by the actuator 2208 is detected by an angle sensor 2209 The control unit 2207 performs an arithmetic operation for this detected rotational angle and supplies the result to the actuator 2208
[00324] An image sensing optical system 2210 forms an image of an object to be photographed on an image sensor 221 1 This image sensor 221 1 is constituted by, e g , a CCD A two dimensional solid state CCD is used in conventional image sensing apparatuses such as video cameras An output from the image sensor 221 1 is output to a recording apparatus or a television monitor through a signal processing circuit (not shown)
[00325] In the conventional image sensing apparatus with the above arrangement, the horizontal and vertical angular velocities caused by a camera shake are detected On the basis of the angular velocities detected, the actuators move the VAP horizontally and vertically to refract incident light, thereby performing control such that the image of an object to be photographed does not move on the image sensing plane of the image sensor Consequently, the camera shake is corrected
[00326] In the current invention, a fluid lens provided with additional components to counteract involuntary motions ("an anti-hand-jittering fluid lens") combines the auto-focusing and variable angle prism functionality into a single low cost component that has no moving parts, and that provides fast response time
[00327] Fig 71 is a cross-sectional diagram 2300 of a prior art fluid lens that is described as operating using an electro-wetting phenomenon The fluid lens 2300 is a substantially circular structure The fluid lens comprises transparent windows 2302, 2304 on opposite sides thereof In Fig 71 , a drop of conductive fluid 2360 (such as water), possibly including dissolved electrolytes to increase conductivity, or to adjust the density of the conductive fluid to match the density of another fluid 2370 that is immiscible with the conductive fluid (such as oil), is deposited on a surface, such as a window A ring 2310 made of metal, covered by a thin insulating layer 2312 is adjacent the water drop A voltage difference is applied between an electrode 2320 (that can also be a ring) and the insulated electrode 2310, as illustrated by the battery 2330 In some embodiments, an insulating spacer 2335 (not shown) is located between the rings 2310 and 2320 The voltage difference modifies the contact angle of the liquid drop The fluid lens uses two isodensity immiscible fluids, one is an insulator (for example oil) while the other is a conductor (for example water, possibly with a salt dissolved therein), which fluids touch each other at an interface 2340 The variation of voltage leads to a change of curvature of the fluid-fluid interface 2340, which in turn leads to a change of the focal length or power of the lens as a result of the refraction of light as it passes from one medium having a first optical index to a second medium having a second, different, optical index In the embodiment shown, an optical axis 2350 is indicated by a dotted line lying substantially along an axis of rotation of the fluid lens 2300 Although the power of the fluid lens, or its focal length, can change by application of suitable signals to the rings 2310 and 2320, which signals cause the curvature of the interface 2340, in the embodiment shown in Fig 71 there is no convenient way to cause the optical axis to deviate away from the axis of rotation of the fluid lens in a deliberate manner or by a desired angle
[00328] The current invention uses the principle of altering the interface shape between two fluids and provides another voltage (or other suitable fluid lens control signal) to control an optical tilt of the fluid interface to adjust an exit optical axis angle or direction relative to the fluid lens One application of such adjustment of the exit optical axis angle is to provide a mechanism and method to compensate the angular movement caused by hand-jittering or hand motion
[00329] Fig 72 is a cross sectional diagram 2400 showing an embodiment of a fluid lens configured to allow adjustment of an optical axis, and Fig 73 is a plan schematic view of the same fluid lens Fig 73 indicates that the two metal ring electrodes 2310, 2320 of the prior art fluid lens shown in Fig 71 have been divided into a plurality of segments, for example four arc pairs (2410a, 2420a), (2410b, 2420b), (2410c, 2420c) and (241 Od, 242Od) A plurality of controllable signal sources, such as voltage sources V l , V2, V3, and V4, are provided, such that each controllable signal source can impress a signal on a selected pair of electrodes independent of the signal applied to any other electrode pair In order to generate a desired curvature of the fluid interface 2440 in the fluid lens 2400, one can control all four voltage controls V l , V2, V3, and V4 to apply a uniform focusing voltage Vf In this mode of operation, the fluid lens 2400 functions in exactly the same manner as the prior art fluid lens shown in Fig 71 However, to generate an optical tilt (or to adjust an optical axis of the fluid lens 2400) using the fluid lens of the current invention, in one embodiment, a horizontal tilt voltage dh and a vertical tilt voltage dv are applied on each of the voltage controls by superimposing the tilt voltages on top of the focusing voltage Vf according to the following equations
V l = Vf + dv V2 = Vf+ dh
V3 = Vf - dv
V4 = Vf- dh
[00330] Application of these new signals V l , V2, V3 and V4 creates a two-dimensional tilted fluid lens, in which horizontal and vertical tilt angles are determined according to the magnitudes and signs of the control voltages dh and dv One can generate such signals involving superposition of a signal Vf and an adjusting signal using well known circuits that are referred to as "summing circuits" in analog circuit design, and by using a digital controller such as a microprocessor-based controller and a digital-to-analog converter to generate suitable fluid lens control signals using digital design principles In Fig 72, fluid lens surface 2445 is shown with a tilt in the vertical dimension caused by application of a signal dv as indicated for V l and V3 The optical axis 2450 of the undeviated fluid lens is shown substantially along the axis of rotation of the fluid lens, and the deviated or adjusted optical axis is shown by dotted line 2455, which is asymmetric with regard to the axis of rotation Notice that surface 2445 not only provides focusing curvature to provide a desired optical power of focal length, but also pervades a mechanism to adjust the optical axis to correct for the hand jittering or hand motion In other embodiments, other applications can be contemplated As an example, one can set the focal length of the lens to a small value (e g , operate the lens as a "fisheye" lens that has a wide field of view and great depth of field) and use the adjustment of the optical axis to tip the field of view to bring some feature of interest within the field of view closer to the center of the field of view In a fisheye lens, features in the center of the field as observed with minimized optical distortions relative to the edge of the field of view, so the object of interest can be observed with reduced distortion Additionally, a fisheye lens typically spreads out objects at the edge of the field of view, so such operation can increase the number of pixels that the object of interest occupies on a planar image sensor, thereby increasing the detail that may be resolved
[00331 ] Fig 74 is a schematic diagram 2500 showing the relationships between a fluid lens and various components that allow adjustment of the optical axis direction The optical axis control system comprises a horizontal angular velocity sensor 2510, a control module 2512 to generate horizontal tilt voltage dh, a vertical angular velocity sensor 1520, a control module 2522 to generate vertical tilt voltage dv, an auto-focusing control module 2530 to generate a focusing voltage Vf, a distributor module 2540 to synthesize the control voltages to control the fluid lens module 2400 to accommodate or to correct for hand jittering Alternately when the axis of the optical system changes orientation, the image on the image sensor will move The processor can extract the magnitude and direction of motion of the object that was not expected to move This can be used as input to the correction circuit
[00332] In some embodiments, the angular velocity sensors 2510 and 2520 are commercially available low cost solid-state gyro-on-a-chip products, such as GyroChips manufactured by BEI Technologies, lnc , One Post Street, Suite 2500 San Francisco, CA 94104 The GyroChip comprises a one piece, quartz micromachined inertial sensing element to measure angular rotational velocity U S Patent No 5,396,144 describes a rotation rate sensor comprising a double ended tuning fork made from a piezoelectric material such as quartz These sensors produce a signal output proportional to the rate of rotation sensed The quartz inertial sensors are micromachined using photolithographic processes, and are at the forefront of MEMS (Micro Electro- Mechanical Systems) technology These processes are similar to those used to produce millions of digital quartz wπstwatches each year The use of piezoelectric quartz material simplifies the sensing element, resulting in exceptional stability over temperature and time, and increased reliability and durability
[00333] In other embodiments, it is possible to divide the two metal rings 2410 and 2420 of Fig 73 into more than four symmetric arc pairs to create more smooth tilt fluid lens For example, one of the embodiments can have 12 symmetric arc pairs layout in a clock numeric topology All the system components shown in Fig 74 will be the same except that the output of distributor 2540 will have 12 voltage control outputs to drive the 12 arc pairs of the fluid lens module The voltage synthesis algorithm in distributor 2540 is based on the gradient of a (dh, dv) vector For example, viewing the fluid lens as if it were a clock, (dh, dv) = (2 5, 0) will have a highest voltage output at a pair of electrodes situated at the 3-o'clock position and the lowest voltage output at a pair of electrodes situated at the 9 o'clock position, and no superimposed voltage would be applied to the electrode pairs nearest the 12 o'clock and 6 o'clock positions It is possible to interpolate the gradient across any intermediate pairs of electrodes around the circle so as to apply a smoothly varying fluid lens control signal In principle, one could build a fluid lens with as many electrode pairs as may conveniently be provided In some embodiments, one of the two ring electrodes can be a continuous ring to provide a common reference voltage for all of the pairs, one element of each pair being the continuous ring, which for example might be held at substantially ground potential, for ease of mounting and assembly, if for no other reason
[00334] Fig 75 is a schematic diagram of an alternative embodiment of a fluid lens 2600, and Fig 76 is a schematic diagram of an alternative embodiment of a distributor module 2640 In Fig 75, there are shown a designed number of symmetric connect points on ring 2610, coupled with a continuous ring 2620 In use, a distributor module 2640 will select a pair of connect points, for example 2612c and 2612i, according to the vector (dh, dv) to apply a tilt voltage tv to the pair of connect points 2612c and 2612i that are disposed symmetrically about a center 2630 of the fluid lens The voltage signals that will be applied are (Vf+tv, Vf-tv) The tilt voltage tv is a function of (dh, dv) and can be predetermined by a mathematical formula or a lookup table By selecting a material having suitable conductivity (or resistivity) for the ring 2610, the voltage can be made to drop uniformly from point 2612c to point 2612i along the ring 2610 such that a voltage gradient is created to control a fluid lens having a continuously tilt along the direction of (dh, dv) In principle, the resistivity of the material should be high, so that there is not an appreciable current flowing in the ring 2610, to minimize heating and to permit a low power supply or battery to be used The ring could be produced by applying a thin layer of conductive material on a nonconductive substrate that is prepared with a desired cross sectional shape For example, one could build a plastic ring 2610 having an inner diameter, and as appropriate, a taper or other shaped surface to match a design criterion, and then coat the surface intended to he adjacent the fluid with a thin layer of a highly resistive conductor, such as carbon or tantalum, which are commonly used as thin film resistors Since there is an insulating layer disposed between the conductor and the fluid in any event, the insulating layer could additionally provide mechanical protection for the thin conductive layer
[00335] Fig 77 is a schematic diagram showing the relationship between a fluid lens 2700 and a pair of angular velocity sensors In a preferred embodiment, two of the angular velocity sensors 2710, 2720 can be integrated with the fluid lens 2700 to form an integrated module 2730 The angular velocity sensors 2710 and 2720 are arranged in an orthogonal relationship to detect two orthogonal angular velocities In some embodiments, the entire control circuitry as shown in Fig 74 can also be integrated into the module 2730 An advantage of this embodiment is ease of mounting the module 2730 No vertical or horizontal alignments are required The module will automatically adjust the lens tilt angle according to the output voltages dh and dv provided by the angular velocity sensors 2710 and 2720
[00336] Figs 78-82 are cross-sectional diagrams of another prior art fluid lens that can be adapted for use according to the principles of the invention Fig 78 is a cross-sectional view of a prior art fluid lens having no control signal applied thereto and exhibiting divergence of transmitted light Fig 79 is a cross-sectional view of a prior art fluid lens having a control signal applied thereto and exhibiting convergence of transmitted light Figs 80, 81 , and 82 are cross-sectional images of fluid lenses having convex, flat and concave interface surfaces as viewed from a position above each lens, respectively
[00337] In one embodiment, using a device comprising a fluid lens, an image sensor, and a suitable memory, it is possible to record a plurality of frames that are observed using the fluid lens under one or more operating conditions The device can further comprise a computation engine, such as a CPU and an associated memory adapted to record instructions and data, for example for processing data in one or more frames The device can additionally comprise one or more control circuits or control units, for example for controlling the operation of the fluid lens, for operating the image sensor, and for controlling sources of illumination In some embodiments, there is a DMA channel for communicating data among the image sensor, the CPU, and one or more memories The data to be communicated can be in raw or processed form In some embodiments, the device further comprises one or more communication ports adapted to one or more of hard- wired communication, wireless communication, communication using visible or infra-red radiation, and communication employing networks, such as the commercial telephone system, the Internet, a LAN, or a WAN
[00338] In this embodiment, by applying suitable selection criteria, one can use or display only a good frame or alternatively a most suitable frame of the plurality for further data manipulation, image processing, or for display According to this aspect of the invention, the device can obtain a plurality of frames of data, a frame being an amount of data contained within the signals that can be extracted from the imager in a single exposure cycle The device can assess the quality of each of the frames against a selection criterion, which can be a relative criterion or an absolute criterion Examples of selection criteria are an average exposure level, an extremum exposure level, a contrast level, a color or chroma level, a sharpness level, a decodability level of a symbol within a frame, and a level of compliance of an image or a portion thereof with a standard Based on the selection criterion, the device can be programmed to select a best or a closest to optimal frame from the plurality of frames, and to make that frame available for display, for image processing, and/or for data manipulation In addition, the operating conditions for the device can be monitored by the control circuit, so that the conditions under which the optimal frame was observed can be used again for additional frame or image acquisition
[00339] In alternative embodiments, it is possible to use the plurality of frames as a range finding system by identifying which frame is closest to being in focus, and observing the corresponding focal length of the fluid lens In such an embodiment, the fluid lens can be operated so as to change its focal length over a range of focal lengths, from infinity to a shortest focal length The device can obtain one or more frames of data for each focal length that is selected, with the information relating to each focal length being recorded, or being computable from a defined algorithm or relationship, so that the focal length used for each image can be determined Upon a determination of an object of interest within a frame (or of an entire frame) that is deemed to be in best focus from the plurality of frames, the distance from the device to the object of interest in the frame can be determined from the information about the focal length setting of the fluid lens corresponding to that frame In some instances, if two adjacent frames are deemed to be in suitable focus, the distance may be taken as the average of the two focal lengths corresponding to the two frames, or alternatively, additional frames can be observed using focal lengths selected to lie between the two adjacent frames, so as to improve the accuracy of the measurement of distance
[00340] In another embodiment, apparatus and methods are provided to counteract changes in the environment that surrounds an apparatus comprising a fluid lens In one embodiment, the apparatus additionally comprises a temperature sensor with a feed back (or feed forward) control circuit, to provide correction to the fluid lens operating signal as the temperature of the fluid lens (or of its environment) is observed to change
[00341 ] Feedback systems rely on the principle of providing a reference signal (such as a set point) or a plurality of signals (such as a minimum value and a maximum value for a temperature range) that define a suitable or a desired operating parameter (such as a temperature or a pressure), and comparing a measured value of the parameter to the desired value When a deviation between the observed (or actual) parameter value and the desired parameter value is measured, corrective action is taken to bring the observed or actual value into agreement with the desired parameter value In the example of temperature, a heater (such as a resistance heater) or a cooling device (such as a cooling coil carrying a coolant such as water) can be operated to adjust an actual temperature Using a feedback loop, the apparatus is made to operate at the desired set point, or within the desired range Feedback loops can be provided using either or both of digital and analog signal processing, and using one or more of derivative, integral and proportional ("D-I-P") controllers
[00342] In some embodiments, a feed- forward system can be used, in which a change (or a rate of change) of a parameter such as actual or observed temperature is measured Corrective action is taken when it is perceived that a condition outside of acceptable operating conditions likely would be attained if no corrective action were to be applied and the observed change (or rate of change) of the parameter were allowed to continue unabated for a further amount of time Feed-forward systems can be implemented using either or both of digital and analog signal processing In some systems, combinations of feedback and feed-forward systems can be applied In some embodiments, multiple feedback and feed-forward controls can be implemented
[00343] In the embodiment contemplated, the operating parameter, such as temperature, of the apparatus comprising a fluid lens, or of the environment in which it is situated, is monitored, and the observed parameter is compared to one or more pre-defined values The one or more predefined values may be fixed (such as a maximum tolerable temperature above which a substance begins to degrade at one atmosphere of pressure) or the one or more predefined values may depend on more than one parameter, such as the combination of pressure and temperature, for example using relationships in a pressure-temperature-composition phase diagram (for example, that a substance or chemical composition in the fluid lens apparatus undergoes a phase change if the pressure and temperature vary such that a phase boundary is crossed, or undergoes a change from covalent to ionic character, or the reverse)
[00344] In yet another embodiment, a system comprising a fluid lens additionally comprises a non- adjustable lens component configured to correct one or more specific limitations or imperfections of the fluid lens, such as correcting for color, spherical, coma, or other aberrations of the fluid lens itself or of the fluid lens in conjunction with one or more other optical components By way of example, a fluid lens may exhibit dispersive behavior or color error In one embodiment, a second optical element is added that provides dispersion of the sign opposite to that exhibited by the fluid lens, so as to correct the dispersive error introduced by the fluid lens In one embodiment, the dispersive element is a diffraction element, such as an embossed grating or an embossed diffractive element As will be understood, different optical materials have different dispersive characteristics, for example, two glass compositions can have different dispersion, or a composition of glass and a plastic material can have different dispersion In the present invention, a material having a suitable dispersive characteristic, or one made to have suitable dispersive characteristics by controlling the geometry of the material, such as in a grating or other diffractive element, can be used to correct the errors attributable to the fluid lens and/or the other components in an optical train
[00345] The aberrations that are possible in a fluid lens can in principle be of any order, much as the aberrations that are possible in the lens or the cornea of a human eye Both a human eye and a fluid lens operate using interfaces between two or more dissimilar fluids In the human eye, there are membranes that are used to apply forces to the fluids adjacent the membranes, by application of muscle power controlled by signals created by the nervous system In a fluid lens, there are forces that are applied, in some instances to the fluid or fluids directly by electromagnetic signals, and in some instances by forces applied to transparent membranes that are adjacent the fluids Both kinds of systems can be affected by external forces, such as the force of gravity and other accelerative forces, changes in ambient or applied pressure, and changes in ambient or applied temperature
[00346] In still another embodiment, there is provided a calibration tool, process, or method for calibrating a fluid lens As one example, a system comprising a fluid lens is operated at one or more known conditions, such as one or more magnifications or one or more focal lengths For each known operating condition, an operating parameter, such as a value of the driving voltage, is observed or measured The observed or measured data is stored in a memory The data in memory is then used to provide calibration data for application to the operation of the fluid lens
[00347] Even if two or more nominally identical fluid lenses are provided, there can be differences that exist in the two fluid lenses themselves, as has been explained hereinbefore When intrinsic differences between two nominally identical fluid lenses exist, application of a substantially identical fluid lens control signal to the two lenses can result in different operative behavior for each lens A default calibration can be provided, for example based on a calibration performed under controlled or defined conditions The default calibration data can be recorded and used at a later time to operate the fluid lens for which the calibration was obtained Using such calibrations is an effective and efficient way to operate a given fluid lens over a defined operating range For many purposes, such information is well worth having and helps to provide a fluid lens that is conveniently operated in a predictable manner Between calibration points, interpolation can be used to achieve an improved resolution Similarly extrapolation may be used to estimate the attributes of a feature beyond the range of measured calibration data
[00348] In addition, as has been indicated, differences may be externally imposed, such as applied voltage, ambient or applied pressure, ambient or applied temperature, and accelerative forces These forces may, individually and in combination, cause one fluid lens to operate somewhat differently than a nominally identical fluid lens When such differences in operating conditions exist, application of a substantially identical fluid lens control signal to the two lenses can result in different operative behavior for each lens Accordingly, it can be helpful to provide a simple and readily applied calibration method for a fluid lens, so that each lens can be calibrated and provided with suitable fluid lens control signals to operate in a desired fashion under the particular conditions pertaining to that fluid lens
[00349] Yet another reason for providing calibration capabilities relates to changes in operation of a given fluid lens over time The operation of an individual fluid lens relies on one or more of the chemical, mechanical, and electrical properties of the components of the fluid lens, which properties may change with time and with use For example, as indicated heremabove, a fluid lens operating in response to electrical signals may undergo electrochemically driven reactions in one or more fluids In addition, a fluid may change properties over time as a result thermal history, such as of repeated heating and cooling cycles or exposure to extremes of temperature As will be understood, as a property of one or more components of a fluid lens changes with time, it may be advantageous to calibrate the operating conditions of interest
[00350] In still a further embodiment, an inertial device such as an accelerometer is provided to determine an orientation of a fluid lens, which orientation information is used to self-calibrate the fluid lens Gravitational and other accelerative forces can cause fluids to move and change shape at a free boundary, or a boundary where two fluids come into mutual contact By way of example, consider a fluid lens that comprises two fluids having slightly different densities Different density implies that equal volumes of the two fluids will have proportionately different masses, because density = mass/volume Therefore, since Force (F) = mass x acceleration, the equal volumes of the two fluids will experience slightly different forces under equal acceleration, such as the acceleration of gravity, or of an external accelerative force applied to a container holding the two fluids One consequence of such an applied acceleration can be a change in the relative locations of the fluids, and as a result, a change in the shape of the interface defined by the surface of contact between the two fluids In addition, the direction of application of the acceleration will also have a bearing on the response of the fluids For example, an acceleration applied normal to a flat interface between the two fluids may have much less of an effect than an acceleration parallel to, or tangent to, a surface component of the interface between the two fluids Since the accelerative force in general can be applied at any angle with regard to an interface between the two fluids, there will in general be differences in response depending on the precise orientation of the applied accelerative force Inertial sensors such as accelerometers and gyroscopes can be useful in determining and in tracking the position of an object over time Through the use of such inertial sensors, it is possible to discern an orientation of an object, and to measure the magnitudes and directions of applied accelerative forces It is possible to calculate or to model how the fluids present in the lens will respond to the forces operating on the lens with knowledge of the orientation of a fluid lens and of the external forces, including that of gravity While the description presented hereinabove may be understood to describe linear accelerative forces such as gravity, it is also possible to perform both the tracking and the calculation of the responses of fluids to forces having non-linear components, forces having rotational components, or time- varying forces In some embodiments, using appropriate sensors for various forces, one can determine the relative orientation of the applied force and the interface between two fluids, and compute what response would be expected As a result of the computation, information is provided for the timely application of restorative forces For example, by modifying the magnitude and/or the field direction of an electrical signal, if necessary as a function of time, the expected distortion of the fluid interface can be counteracted In one embodiment, solid state accelerometer sensors are provided that operate at sufficiently high rates as to determine the magnitude and orientation of an external force Accelerometers having response rates of at least 10,000 Hz are available from Crossbow Technology, Inc located at 4145 N First Street, San Jose, CA 95134
[00351 ] In yet an additional embodiment, in an apparatus comprising a fluid lens, the fluid lens is operated to provide corrective properties with regard to such distortions as may be caused by vibration, location or orientation of the lens, chromatic aberration, distortions caused by higher order optical imperfections, and aberrations induced by environmental factors, such as changes in pressure As has been explained hereinbefore, using accelerative forces as an example, the fluid lens may in some instances be subjected to various distorting forces or to forces that cause degradation of the operation of the fluid lens from that which is desired In other instances, the fluid lens may have inherent imperfections, such as chromatic aberration or higher order optical imperfections It is possible to analyze such optical imperfections in various ways, such as the use of a calibrated imaging system comprising a source, at least one image sensor, and hardware and/or software configured to analyze optical information to assess whether errors or imperfections exist in an optical component under test The calibrated imaging system in some instances can be a laboratory setting in which highly sophisticated equipment is employed to perform tests In other instances, the calibrated test system can comprise a source that provides a known optical signal that is passed through an optical component under test, and the analysis of the resulting signal that emerges from the optical component under test The calibrated test system in some embodiments is a system or device suitable for use in the field, so that periodic calibration can be performed in a convenient and efficient manner, if necessary by personnel who are not familiar with all of the sophistications of optical testing in a laboratory setting
[00352] In one embodiment, the optical component can be modeled in the frequency domain as a transfer function, wherein a known applied input signal l(s) is provided and an observed output signal O(s) is measured An observed transfer function Hobs(s) = O(s)/I(s) is determined Hobs(s) can then be compared to a desired transfer function H(s), to determine a corrective factor or relation C(s) that should be applied to the system under test to cause it to perform as desired, where C(s)Hobs(s) = H(s), or C(s) = H(s)/Hobs(s) Once the corrective factor or relation C(s) has been determined, it (or its time domain equivalent) can be applied to drive the fluid lens so as to reduce the observed imperfection or imperfections Transfer function concepts, discrete time mathematical procedures, digital filters and filtering methods, and circuitry (including hardware and software) that can handle the required detection, analysis and computation, and can be used to apply corrective action are described in many texts on real time digital signal processing Hardware such as digital signal processors are commercially available from multiple vendors
[00353] Applications for fluid lenses include their use in one or more types of camera, such as cameras in cell phones, use in higher quality digital cameras such as those having a high powered zoom lens, and use in cameras that can provide auto focus, and pan, tilt, and zoom ("PTZ") Panning is moving a camera in a sweeping movement, typically horizontally from side to side Tilting is a vertical camera movement, e g in a direction orthogonal to panning Commercially available PTZ video and digital cameras that use mechanical redirection of the camera and refocusing of its lens are well known, and are often used in surveillance In order to accomplish such features as tilt or pan, one needs to reorient the interface between two optically dissimilar fluids so that the optical axis is relocated from its original direction horizontally (pan) or is relocated from its original direction vertically (tilt) With a fluid lens, both relocations can be accomplished in a single redirection of the optical axis at an angle to both the horizontal and vertical directions simultaneously Such redirections are readily computed using spherical geometry coordinates, but can also be computed in any coordinate system, including using projection from three dimensions to two dimensions, for example as is commonly done in x-ray crystallography as an example One method to accomplish all of auto focus, pan, tilt, and zoom is to apply several features in a single device Auto focus and zoom have been addressed hereinbefore Pan and tilt, or more generally, redirection of the optical axis to a new orientation that is non-collinear with the original optical axis, can be accomplished by providing an electrode pair comprising a first plurality of first electrodes and at least one second electrode, and applying voltages to at least one electrode of the first plurality and the at least one second electrode so that the surface shape of the interface between the two fluids in the fluid lens is caused to change a measure of asymmetry as measured with respect to the optical axis of the fluid lens prior to the application of the voltages In general, to accomplish the provision of an asymmetry, either the applied voltages will include an asymmetric component, or the electrodes to which the voltages are applied will be positioned in an asymmetric geometrical relationship, or both By applying a voltage field having an asymmetry to the fluids in the fluid lens, the fluids will respond in a manner to adjust the voltage gradients across the interface to be as uniform as possible, thereby causing the fluids to take up an interface shape that comprises an asymmetric component, and thereby directing light along a new optical axis that is non-collinear with the optical axis that existed prior to the application of the voltage
[00354] We will now briefly describe examples of power supplies that are useful for powering a fluid lens In one embodiment, a suitable power supply for driving the fluid lens is a square wave power supply that is biased to operate in the range 0 to V volts, where V is either a positive or a negative voltage, which may be thought of as a unipolar supply One embodiment is to use a bipolar power supply that is capable of providing voltages between +V l /2 and -V 1 /2 volts, with an added bias voltage of +V l /2 volts (causing the range to extend from 0 volts (= +V l/2 volts bias + [-V 1 /2 volts] supply) to +V l volts (= +V l/2 volts bias + V l/2 volts supply), or alternatively using an added bias voltage of -V l /2 volts (causing the range to extend from -V l volts (= -Vl /2 volts bias + [-V 1/2 volts] supply) to 0 volts (= -V l/2 volts bias + V l /2 volts supply) The summation of two voltages is easily accomplished with a summing circuit, many variations of which are known In one embodiment, the bias voltage supply operates at a fixed voltage In other embodiments, the bias voltage supply is configured to provide a plurality of defined voltages, based on a command, which may be provided by setting a switch, or under the control of a microprocessor In some embodiments, voltage supplies are used that can be controlled by the provision of a digital signal, such as a digital-to-analog converter controlled by a digital code to define an output signal value In another embodiment, voltage supplies that are controlled using a frequency- to-voltage converter, such as the National Semiconductor LM2907 or LM 2917 frequency-to-voltage converter, can be employed using a pulse train having a controllable frequency as a control signal It is believed that electrochemical effects within the fluid lens are operative under sufficiently high applied voltages, thereby making the use of a unipolar supply advantageous in some instances
[00355] In other embodiments, power supplies that provide voltage signals having both positive and negative peak voltages of the order of one volt to hundreds of volts are provided In some embodiments, the output voltages are provided as square waves that are generated by a driver integrated circuit such as is commonly used to operate electroluminescent lamps, such as are found in cellular telephones
[00356] Fig 83 is a schematic block diagram showing an exemplary fluid lens driver circuit 2900 The circuit is powered by a battery supply 2910, typically operating in the range of 3 to 4 5 volts, although circuits operating with batteries of other voltages and also operating from fixed wall mount power supplies can be designed A voltage reference 2920 is provided which may have associated with it a low drop out voltage regulator Input signals in the form of a clock signal (a frequency or a pulse train) and digital data line are provided to a I2C serial interface 2930 for control of this driver circuit by an external device, such as the microprocessor 4040 of Fig 55 The serial interface 2930 is in communication with a controller 2940 (such as a commercially available microcontroller) for coordinating the activities of the fluid lens driver circuit 2900, the oscillator 2960, to set the output frequency, and a digital-to-analog (DAC) converter 2950, to set the output voltage The DAC is provided with a reference voltage by the voltage reference 2920 In some embodiments
Figure imgf000069_0001
DAC
[00357] The controller 2940 is in communication with an oscillator 2960 that provides a timing signal This oscillator 2960 can be signaled to enter a power down state by a suitable signal communicated from an external source at 2962, which in some embodiments can be a user or can be another controller The controllers contemplated herein are in general any microprocessor-based controller including a microcontroller, a microprocessor with associated memory and programmed instructions, or a general purpose digital computer The controller 2940 is also in communication with a wave form generator 2945 that creates the square wave waveform for the bridge driver output stage 2980 The waveform generator 2945 also synchronizes the DAC transitions with the output waveform through the controller 2940
[00358] The output of the DAC 2950 sets the output voltage level of the high voltage generator 2970 such that the output voltage is proportional to the output of the DAC 2920, and thereby is configured to be controlled with high precision by a digital source such as a computer In some embodiments, appropriate feedback circuitry is contained in this portion of the circuit to keep the output voltage constant over a range of input voltage, load and environmental conditions The high voltage created by the high voltage generator 2970 is an input to the bridge driver 2980 The high voltage generator has a stable output ranging from 0 Volts to approximately 40 Volts for the Vaπoptic ASM- 1000 fluid lens This generator may utilize an inductor 2972 and or capacitors to create the higher voltage However other circuit configurations might also be used, for example capacitive voltage multipliers The bridge driver 2980 creates the high voltage switching signals OUTP and OUTM which drive the fluid lens 2995 In some embodiments, the output can be applied to a load such as fluid lens 2995 using the commutating circuit of Fig 58
[00359] The output to the fluid lens is a voltage signal that is wave shaped by the bridge driver using a wave form signal from the wave form generator The term "bridge driver" should be understood as follows The load is connected between two amplifier outputs (e g , it "bridges" the two output terminals) This topology can double the voltage swing at the load, compared to a load that is connected to ground The ground-tied load can have a swing from zero to the amplifier's supply voltage A bridge-driven load can see twice this swing because the amplifier can drive either the + terminal of the load or the - terminal, effectively doubling the voltage swing Since twice the voltage means four times the power, this is a significant improvement, especially in applications where battery size dictates a lower supply voltage, such as in automotive or handheld applications
[00360] As already indicated, one can also sum the output of the circuit described with a reference signal of suitable magnitude and polarity so that the voltage swing experienced by the load is unipolar, but of twice the magnitude of either the positive or negative voltage signal relative to ground The power advantage just referred to is also present in such an instance, because power P is given by the relationship V2/R or V2/Z, where V is voltage, R is resistance, and Z is impedance Since the voltage swing in both embodiments is the same v volts (e g , from -v/2 to + v/2, from 0 to + v, or from -v to 0), the power available is unchanged Stated in terms that will be familiar to those acquainted with the principles of electrical engineering, since the reference voltage of an electrical system (for example ground potential) may be selected in an arbitrary manner, merely shifting the voltages applied to the fluid lens from one reference to a different reference should not change the net power delivered to the fluid lens However, when considered from the perspectives of electrochemical principles, it is recognized that different electrochemical reactions can be made to occur (or can be suppressed) depending on whether an applied electrical signal is a positive-going, or a negative-going, voltage relative to the reference voltage (e g , polarity may be an important feature in a particular chemical system)
[00361 ] Figs 84 and 85 are diagrams that show an LED die 3010 emitting energy in a forward direction through a fluid lens 3020 The divergence of the emitted light is modified with the fluid lens In Fig 84 the divergence of the emitted light is modified because of the optical power of the fluid lens In the example shown the light exiting the fluid lens could be considered to approximate collimated light even though the light exiting the LED is diverging In a situation where the curvature of the fluid lens is more extreme than is shown in Fig 84, the light may be focused on a smaller region In Fig 85 the power of the fluid lens has been reduced to approximately zero so that the divergence of the light emitted by the LED is substantially unchanged The comparison of the light patterns in Figs 84 and 85 indicates that such systems can be used to control the coverage (in area) at a target of interest, for example a bar code that one is interested in reading with a hand held reader or imager In some embodiments, one or more windows on a reader or scanner may also be used to protect the optical system including the fluid lens from adverse environmental conditions
[00362] It should be appreciated that although the details may change, this concept also applies to encapsulated LEDs, as well as to fluid lens assemblies that may contain additional optical elements such as spherical, aspherical and cylindrical lens elements [00363] In one embodiment, such a system is expected to more efficiently utilise a higher fraction of light emitted by the LEDs For example when viewing bar code patterns near the imager, a more diverging illumination pattern is desirable in order to be assured that larger bar code patterns are illuminated over their entire extent and when viewing bar code patterns at a larger distance from the imager, a more converging illumination pattern is desirable so that illumination is not wasted by falling outside the optical field of interest
[00364] Figs 87, 88, and 89 show diagrams of a laser scanner comprising a laser 31 10, a collimating lens 3120, and a fluid lens 3130 in various configurations In Fig 86 the fluid lens is configured to have a first optical power, a first focal length and a first principal beam direction The light beam emanating from the fluid lens 3130 is focused to have a narrowest beam width at a plane 3140 situated at a first distance Dl from the fluid lens 3130 In Fig 87 the fluid lens is configured to have a second optical power, a second focal length and a first principal beam direction In Fig 87, the light beam emanating from the fluid lens 3 130 is focused to have a narrowest beam width at a plane 3141 situated at a second distance D2 from the fluid lens 3130, such that D2 is greater than D l , and the first principal beam direction is not changed when the focal length of the fluid lens 3130 is changed In Fig 88 the fluid lens is configured to have a first optical power, a first focal length and a second principal beam direction In Fig 88, the light beam emanating from the fluid lens 3130 is focused to have a narrowest beam width at a plane 3140 situated at a first distance corresponding to a distance D l from the fluid lens 3130 measured along the second principal beam direction of Fig 86, but because the beam in Fig 88 is emanating at an angle (e g , the third principal beam direction is not the same as the first principle beam direction), the lateral distance that the beam is "off-axis" is Ll Other optical powers, focal lengths and principle beam directions can be achieved by properly configuring and energizing the fluid lens 3130
[00365] The present inventions are intended to take advantage of fluid lens zoom optical systems Fluid zoom lens configurations can be used in bar code scanners to enable imaging of different bar codes at various distances from the bar code scanner In bar code scanners manufactured today, often a large working distance is achieved by stopping down the lens aperture to increase the optical depth of field However this has two disadvantages First, when the lens stop is smaller, the optical system point spread function increases thereby making it more difficult to scan bar code patterns with narrow bar code elements Second, when the lens stop is smaller, less light enters the lens thereby reducing the signal-to-noise ratio of the system The lower SNR requires the operator to hold the reader still for longer period of time The effect is that the bar code scanner has an increased sensitivity to hand motion In addition, because longer periods of time are required, the user is more likely to become fatigued
[00366] Object distance measurements can be made if the range of, or the distance to, the object is known A fluid lens system can be used to implement a range finding system In one embodiment, the fluid lens would be focused at a number of focus positions and the position with the best focus, as determined by any of a number of metrics, would be associated with that fluid lens position By knowing the fluid lens drive voltage that caused the fluid lens to have an optimally focused image, and using a look-up table, the associated distance from the system for that specific fluid lens operating voltage can be determined By knowing the range, the magnification can be calculated and thus the object width associated with a given number of pixels at the imager is known or can be deduced In this way a system such as a bar code reader or imager can calculate the width of specific object features, such as bar code element widths or the dimensions of a package
[00367] A fluid lens variable aperture can be added to a bar code system In some embodiments, the aperture would be used in the portion of the optical system that receives light and would allow the system to optimally trade light efficiency against point spread function width and depth of field When a small aperture is used, the optical system will have a larger depth of field, but adversely the optical throughput of the system is reduced (i e , less light gets through the system) and the point spread function (proportional to the minimal element size that can be resolved) is also reduced In some embodiments, a bar code system is expected to be configured to initially have the optical system set for an optimum light throughput, and if a good read is not achieved then the aperture size could be reduced in order to extend the depth of field in an effort to decode any bar code pattern that may be within the bar code scanner field of view
[00368] In one embodiment, a fluid lens is used as a variable aperture One implementation of this use of a fluid lens involves adding a colorant to at least one of the fluids to make that fluid opaque in at least a region of an electromagnetic spectral range of interest, such as being opaque at a specified range in the visible spectrum Voltage is applied to the lens from a power supply such that the fluid lacking the colorant that absorbs in the specified region "bottoms" against the opposite window, thereby forming a clear aperture in that spectral range of interest In one example colorant can be added to the water component of an oil water fluid lens
[00369] In an alternate embodiment, if a window is curved such that it is effectively parallel to the curve of the water-oil interface, the liquid lens can in some instances be configured to perform as a variable filter In such an embodiment, the oil would not bottom against the opposite window, but would produce a thickness of the water that is essentially constant as a function of radius across a portion of the window This thickness would be varied by varying the applied voltage The voltage-controlled thickness of the light-absorbing water would thereby determine the amount of light passing through the fluid filter If the colorant has light absorbing characteristics in specific wavelengths, then the amplitude of the light in these wavelengths passing through the fluid filter would be varied by varying the applied voltage
[00370] By having more than one lens element configured as a fluid lens, for example a lens triplet, the optical aberrations present in a single element can be reduced for the assemblage of lenses and this would result in a higher quality optical image The techniques for optimizing a triplet are well known in the lens design art However, it is typically the case that any given lens is optimized for a given focal length system Typically, if a lens is optimized for one combination of optical elements, it is not optimally configured when one of the lens surfaces is changed as would happen when a single fluid element is operated to change an optical parameter, such as a focal length By adding a second fluid lens, the combination of the first lens and the second lens can be optimized to minimize total system aberrations For different settings of the first lens, corresponding changes in the settings of the second lens can be made to obtain an optimal combination These optimized relationships between the two fluid lens surfaces curvatures, i e surface optical power, and thus also the control voltages, can be contained for example in a table that is recorded in a machine readable memory Thus for any given setting of desired system optical power, the appropriate drive voltages for the two fluid lenses can be developed, and applied in accordance with the recorded values Where desirable or advantageous, the fineness of the table resolution may be increased through use of linear or higher order interpolation and extrapolation [00371 ] Other prior art fluid lens systems that operate using mechanical forces to control the shape and properties of a fluid lens are described in U S Patent No 4,514,048 to Rogers, which has already been incorporated herein by reference in its entirety Additional disclosure relevant to variable focus lenses is presented in the following U S Patents No 2,300,251 issued October 17, 1942 to Flint, No 3, 161 ,718 issued December 15, 1964 to DeLuca, No 3,305,294 issued February 21 , 1967 to Alvarez, and No 3,583,790 issued June 8, 1971 to Baker, all of which are hereby incorporated by reference herein in their entirety
[00372] Machine-readable storage media that can be used in the invention include electronic, magnetic and/or optical storage media, such as magnetic floppy disks and hard disks, a DVD drive, a CD drive that in some embodiments can employ DVD disks, any of CD-ROM disks (ι e , read-only optical storage disks), CD-R disks (ι e , write-once, read-many optical storage disks), and CD-RW disks (ι e , rewπteable optical storage disks), and electronic storage media, such as RAM, ROM, EPROM, Compact Flash cards, PCMCIA cards, or alternatively SD or SDlO memory, and the electronic components (e g , floppy disk drive, DVD drive, CD/CD- R/CD-RW drive, or Compact Flash/PCMCIA/SD adapter) that accommodate and read from and/or write to the storage media As is known to those of skill in the machine-readable storage media arts, new media and formats for data storage are continually being devised, and any convenient, commercially available storage medium and corresponding read/write device that may become available in the future is likely to be appropriate for use, especially if it provides any of a greater storage capacity, a higher access speed, a smaller size, and a lower cost per bit of stored information Well known older machine-readable media are also available for use under certain conditions, such as punched paper tape or cards, magnetic recording on tape or wire, optical or magnetic reading of printed characters (e g , OCR and magnetically encoded symbols) and machine-readable symbols such as one and two dimensional bar codes
[00373] Many functions of electrical and electronic apparatus can be implemented in hardware (for example, hard-wired logic), in software (for example, logic encoded in a program operating on a general purpose processor), and in firmware (for example, logic encoded in a non-volatile memory that is invoked for operation on a processor as required) The present invention contemplates the substitution of one implementation of hardware, firmware and software for another implementation of the equivalent functionality using a different one of hardware, firmware and software To the extent that an implementation can be represented mathematically by a transfer function, that is, a specified response is generated at an output terminal for a specific excitation applied to an input terminal of a "black box" exhibiting the transfer function, any implementation of the transfer function, including any combination of hardware, firmware and software implementations of portions or segments of the transfer function, is contemplated herein
[00374] [End of text substantially as presented in U S Patent Application No 1 1/781 ,901 ]
[00375] [The following is text substantially as presented in U S Patent Application No 60/961 ,036]
[00376] The present invention is directed to a lens module containing a lens element and a force element The lens element includes a deformable member comprising two surfaces, such as a deformable membrane, which may be elastically deformable, with at least one of the surfaces being in force communication with a fluid The term "force communication" may be used herein because both of the surfaces may be in contact with a fluid, whereas only one of the fluids may be used to transmit force to the deformable membrane in order to selectively change the focal length, and/or the orientation of the optical axis, of the lens element (This fluid may also be considered the "working" fluid ) Hence, "force communication" can have the meaning that force transmitted to either the deformable member or the fluid will produce a substantially proportional response in the other, with "substantially proportional" meaning simply that the fluid and the deformable member are part of a closed system For example, if the needle of a large syringe could be inserted into an inflated balloon without popping it, motion of the syringe plunger to add air to, or withdraw air from, the balloon would produce a substantially proportional change in the size and shape of the balloon, taking into account its elasticity and the fact that some of the force from the added or withdrawn air is reflected by a change in air pressure within the balloon In contrast, a change in the ambient air pressure may also produce some change in the size and/or shape of the balloon, but because the balloon and the ambient atmosphere are not part of a closed system this change will be incidental and non-selective The air in the syringe and inside the balloon is the working fluid, in contrast to the ambient atmosphere
[00377] It should also be noted that while the simplest construction of such a lens element involves a sealed volume of fluid, and a deformable member having one side in direct contact with the fluid and another side in direct contact with the ambient atmosphere, many variations on this basic construction are possible and fall within the scope of the present invention For example, both sides of the deformable member could be in contact with sealed volumes of fluid, but only one side would be in force communication with a working fluid, while the other side might be in contact with, or only facing, a fluid volume that is used for a purpose other than deforming the deformable member in order to change focal length and/or orientation of the optical axis, such as to prevent contamination of the membrane surface, or as a filter, or as an additional optical element Or, the sealed volume could contain both a liquid volume and a gaseous headspace, with the gas being in direct contact with the membrane rather than the liquid, possibly itself separated from the liquid by another membrane For this reason, the side of the deformable member that is in force communication with a sealed fluid volume may also be referred to as the side facing the fluid, in order to embrace those configurations in which the deformable member does not directly contact the optical fluid
[00378] The present application may also refer to an "optical path" in describing certain aspects of the present invention In an imaging system including an optical system and an imager, if the optical axis is not blocked (as by a shutter, ins, lens cover, or otherwise), and if sufficient light is available, at any given moment the imager will be receiving an image representative of some object external to the imaging system The optical path may be broadly defined as the path along which light rays travel from the external object, through the optical system, to the image sensor However, the optical path is not necessarily bounded to include all of the light rays reaching the image sensor, but includes any portion thereof, up to and including the path along which any single light ray has traveled between the external object and the sensing area of the image sensor
[00379] As previously stated, a variable lens may comprise a deformable interface between two fluids having dissimilar optical indices The shape of the interface can be changed by the application of force supplied by a force element so that light passing across the interface can be directed to propagate in desired directions As a result, the optical characteristics of such lenses, such as whether the lens operates as a diverging lens or as a converging lens, its focal length, and the orientation of its optical axis, can be changed, generally by changing a deformable element that functions as at least one face or surface of the lens among flat, convex, and concave profiles
[00380] The lens element may be a single component, such as a fluid-filled elastomer, polymer, or plastic, for example, a transparent oil-filled elastomer material which has an elastic memory Alternatively, the lens element may be two or more components, with an optical fluid (such as water or oil) entrapped or sandwiched between a boundary layer, such as glass or plastic, and a deformable member, in which configuration the optical fluid and the deformable member would together comprise the lens element When a membrane is used as the deformable member, suitable materials include polydimethylsiloxane, or PDMS, such as Sylgard® 184 silicone elastomer, available as a kit from Dow Corning Corporation, Midland, Michigan, USA The membrane thickness may be selected based on factors such as the size of the lens module in question and may be, for example, from about 0 05 to about I mm, for example, 0 1 , 0 2, 0 3, or 0 4 mm
[00381 ] The overall size of the lens module of the present invention is not critical and may be varied depending on the size of the available components, the device into which it will be placed or assembled, and the needs of the user The guidelines provided herein for the size of the lens module are with reference to the major dimension of a cross-section of the lens module (not merely the lens element) as viewed along the optical axis For example, when the lens module is cylindrical as represented in Fig 132, having lens element 5802 and housing 5804, the cross-section 5808 as viewed along the optical axis 5810 will be a circle, and the larger cross- sectional dimension will be the diameter 5806 of the circle (represented as a dotted line), there being no smaller cross-sectional dimension If the cross-section is elliptical, as where the lens element is itself elliptical and the housing conforms to that shape, the major dimension will be the major axis of the ellipse In general, then, the lens module will have a major dimension of from about 5, 7, or 9 mm to as large as about 1 1 , 13, 15, or 20 mm The size may be selected in order to maximize or achieve drop-in compatibility with existing devices, for example, in camera-enabled cellular telephones, a cylindrical lens module having a diameter of about 9, 9 5, or 10 mm may be preferred
[00382] When an optical fluid is used, its properties should be selected for compatibility with the other materials, stability under use, tolerance for the anticipated temperatures at which it will be used, and similar factors Optical grade oils, such as optical grade mineral oils, may be used One suitable optical fluid is Type A immersion oil, available from Cargille-Sacher Laboratories lnc , Cedar Grove, New Jersey, USA Another suitable fluid is the Santovac® polyphenyl ether-based optical fluid SL-5267, available from Arch Technology Holding LLC , St, Charles, Missouri, USA Water may also be used, such as de-ionized water
[00383] When it is desired to minimize loss of light transmitted through the lens element due to reflection loss, the materials selected for the optical fluid, deformable member, and any boundary layer should have similar indices of refraction For example, where the lens element includes a glass boundary layer, an optical fluid, and a deformable membrane, one should consider the difference in indices of refraction both of the optical fluid compared to the boundary layer, and of the optical fluid compared to the deformable membrane The greater the difference in indices, the more light will be loss to reflection as it attempts to pass from one material (such as glass) to the next (such as an immersion oil) Conversely, the closer the indices, the less light will be lost to reflection In this context the indices will ideally be identical, and preferably will be within about +/- 0 001 to 0 01 , such as about 0 002 However, there may be situations where differences in the indices of refraction may be advantageous
[00384] It is also possible to vary the thickness of the deformable member over the deformation area, which would result in a structure having aspheric attributes while retaining the variability otherwise enabled by the present invention
[00385] Choosing an optical fluid with a relatively high index of refraction will reduce the amount of deformation needed to obtain a given change in focal distance For example, a suitable index of refraction would be in the range of from about 1 3 or about 1 5 to about 1 6 or about 1 7, such as an index of about 1 5 or about 1 6
[00386] The lens system containing a variable lens will then include a force element to cause the lens to vary, as by direct or indirect application of electrical, mechanical, hydraulic, pneumatic, thermal, magnetic, or other force In this context, mechanical force is provided by the motion of a solid object, such as a piston, composed of, for example, metal or plastic, hydraulic force is produced by the motion of a liquid, pneumatic force is produced by the motion of a gas, thermal force is produced by a change in temperature, and magnetic force may be produced by the motion of electric current through a wire The force may be applied externally and/or internally to the fluid component that is used to transmit the force to the deformable member For example, in a relatively simple internal force configuration involving a fluid in a cylindrical container sealed by a deformable member at one end, the cylinder may contain a piston that is in sealed connection with the cylinder wall and which can be moved back and forth within the fluid to effect changes in the shape of the deformable member Alternatively, in an external force configuration, the wall of the cylinder may be deformable and the force element may be capable of compressing at least a portion of the cylinder wall by squeezing it from the outside, somewhat like a tube of toothpaste
[00387] The force element is capable of providing sufficient force to deform the deformable member and is operably coupled to that member in order to allow the force to travel from the force element to the deformable member In a relatively simple configuration the force element may act directly on the deformable member, or on the fluid which will then act on the deformable member, but many variations on this are possible within the scope of the invention There may be one or more further elements positioned between the force element and the deformable member, between the force element and the fluid, and/or between the fluid and the deformable member, such as additional deformable members, valves, structures for damping the transmission of force to, from, or within the fluid, and so on In one particular embodiment, the force element acts on a pressure element positioned on the side of the deformable member facing away from the working fluid, the pressure element generally having an annular shape and contacting an outer portion or circumference of the deformable member, as in the shape of a ring or washer, and the force element pushes or pulls on the pressure element, which in turn pushes or pulls on the deformable member, causing deformation as represented in the transition from Fig 91 to [00388] The pressure element may be a variety of materials, including metal, plastic, and ceramic The choice of material will depend on compatibility with other materials and on the desired response to force exerted by the deforming element If it is desired that the pressure element not itself deform, it should be an inelastic material such as metal, ceramic, or plastic If, however, it is desired or necessary that the pressure element change its shape or configuration in response to the deforming element, it should be composed of a deformable material such as an elastomer
[00389] A control system is provided to control the force element While the control system will generally be powered electrically rather than, for example, mechanically, it may further include hydraulic, pneumatic, mechanical, and/or magnetic control features depending on the nature of the force element(s) being used For example, when the force element consists of electroactive polymer, the control system may be an electrical control system, which will control the electroactive polymer by controlling whether current or voltage is being supplied to the electroactive polymer, and by controlling the level or amount of such current or voltage, in order to control the deformation of the electroactive polymer An electrical control system may also be used when the force element is a voice coil, with the level or amount and/or polarity of current or voltage controlling the strength and/or direction of the magnetic field generated in the voice coil Where the force element is hydraulic or pneumatic the control system may include pistons, pumps, valves, piezoelectric elements, and similar components to regulate aspects such as the volume, force, and direction of fluid being moved
[00390] The lens module may be configured with multiple force elements, each being energizeable on its own circuit, or, with one or more force elements each having multiple, separately energizeable circuits By choosing which circuits to energize, and how much control signal to apply, the control system may control not only the formation and magnitude of convex and concave surfaces in the deformable member, but also the tilt of those surfaces In this context, tilt refers to the possible combinations of pitch and yaw that may be used to configure the shape of the deformable member to have surface shapes other than symmetric to an axis normal to the surface of the deformable member when that surface is flat and passing through its center A simple example is shown in Fig 131 , in which focus fluid 5702 has been further represented as having convex surface 5704, shown as having an asymmetric shape in response to selective application of control signals to a multicircuit force element, such as that shown in Fig 120
[00391 ] In one embodiment the present invention is directed to variable lenses actuated by polymeric actuators, and to lens systems, optical systems, and devices containing such variable lenses In another embodiment the present invention is directed to variable lenses actuated by force elements that are arranged symmetrically around the optical axis of such lenses, as will be further explained herein
[00392] The variable lens includes at least one component capable of changing focal length, and/or the orientation of an optical axis passing through it, by deforming in response to an applied force The deformation may or may not be elastic, in the sense of the component returning to its original configuration if the applied force is removed or discontinued However, it is anticipated that in most uses it will be desirable for the component to return to its original configuration, and to accordingly be elastically deformable [00393] Polymeric actuators, including electroactive polymers, may be used as a source of mechanical force to change the interface in an adaptive lens The phrase "polymeric actuators" is used herein to refer to a category of polymeric materials that respond to a change in electric stimulation, such as voltage, with physical movement These include electroactive polymer materials available from Artificial Muscle, lnc , of Menlo Park, California, the ion conductive actuators and conducting polymer actuators available from EAMEX Corporation of Osaka, Japan, nano actuators/transducers and artificial muscles available from Environmental Robots lnc , of Albuquerque, New Mexico, and electroactive polymers available from Micromuscle AB of Linkoping, Sweden
[00394] Examples of electroactive polymers and related technologies are contained in the following published patent applications, patents, and articles Pelrine et al , U S Patent Application Ser No 10/393,506, filed Mar 18, 2003, published January 15, 2004 as US20040008853, entitled "Electroactive Polymer Devices for Moving Fluid", Pelπne et al , U S Provisional Patent Application Ser No 60/365,472, filed Mar 18, 2002, entitled "Electroactive Polymer Devices For Moving Fluid,", U S Patent Application Ser No 09/792,431 , now Pelrine et el , U S Pat No 6,628,040 entitled "Electroactive Polymer Thermal Electric Generators," filed Feb 23, 2001 , U S Provisional Patent Application Ser No 60/184,217 filed Feb 23, 2000, entitled "Electroelastomers and Their Use For Power Generation", U S Provisional Patent Application Ser No 60/190,713, filed Mar 17, 2000, entitled "Artificial Muscle Generator", U S Patent Application Ser No 10/154,449, now Pei et al , U S Pat No 6,891 ,317 entitled "Rolled Electroactive Polymers," filed May 21 , 2002, U S Provisional Patent Application Ser No 60/293,003 filed May 22, 2001 , U S Patent Application Ser No 10/053,51 1 , now Kornbluh et al , U S Pat No 6,882,086, entitled "Variable Stiffness Electroactive Polymer Systems," filed Jan 16, 2002, U S Provisional Patent Application Ser No 60/293,005, filed May 22, 2001 , U S Provisional Patent Application Ser No 60/327,846 entitled Enhanced Multifunctional Footwear, filed Oct 5, 2001 , U S Patent Application Ser No 09/619,847, now Pei et al , U S Pat No 6,812,624, entitled "Electroactive Polymers," filed JuI 20, 2000, U S Provisional Patent Application Ser No 60/144,556, filed JuI 20, 1999, entitled "High-speed Electrically Actuated Polymers and Method of Use", U S Provisional Patent Application Ser No 60/153,329, filed Sep 10, 1999, entitled "Electrostπctive Polymers As Microactuators". U S Provisional Patent Application Ser No 60/161 ,325, filed Oct 25, 1999, entitled "Artificial Muscle Microactuators", U S Provisional Patent Application Ser No 60/181 ,404, filed Feb 9, 2000, entitled "Field Actuated Elastomeπc Polymers", U S Provisional Patent Application Ser No 60/187,809 filed Mar 8, 2000, naming R E Pelrine et al as inventors, and titled "Polymer Actuators and Materials", U S Provisional Patent Application Ser No 60/192,237, filed Mar 27, 2000, entitled "Polymer Actuators and Materials II", U S Provisional Patent Application Ser No 60/184,217, filed Feb 23, 2000, entitled "Electroelastomers and their use for Power Generation", U S Patent Application Ser No 10/007,705, now Pelrine et al , U S Pat No 6,809,462 entitled "Electroactive Polymer Sensors," filed Dec 6, 2001 , U S Provisional Patent Application Ser No 60/293,004, filed May 22, 2001 , U S Patent Application Ser No 09/828,496, now Kornbluh et al , U S Pat No 6,586,859, entitled "Electroactive Polymer Animated Devices", U S Provisional Application Ser No 60/ 194,817, filed Apr 5, 2000, U S Patent Application Ser No 10/066,407, entitled "Devices and Methods for Controlling Fluid Flow Using Elastic Sheet Deflection," filed Jan 31 , 2002, U S Patent Application Ser No 09/779,203, now Pelrine et al , U S Pat No 6,664,718, filed Feb 7, 2001 , entitled, "Monolithic Electroactive Polymers,", U S Provisional Patent Application Ser No 60/181 ,404, filed Feb 9, 2000, U S Patent Application Ser No 10/090,430, now Heim et al , U S Pat No 6,806,621 , filed on Feb 28, 2002, entitled "Electroactive Polymer Rotary Motors,", U S Provisional Patent Application Ser No 60/273, 108, filed Mar 2, 2001 , entitled "Electroactive Polymer Motors", Benslimane et al , U S Patent Application Ser No 1 1 /592,675, filed Nov 3, 2006, published as U S Patent Application Publication No 200701 16858 on May 24, 2007, entitled "Multilayer Composite and a Method of Making Such", U S Patent Application Ser No 10/415,631 , filed Aug 12, 2003, U S Patent Application Ser No 10/499,429, filed Dec 30, 2004, U S Patent Application Ser No 10/528,503, filed Mar 27, 2005, Zama et al , U S Patent Application Ser No 10/523,985, published as U S Patent Application Publication No 20060076540 on Apr 13, 2006, entitled "Process for Producing Conductive Polymer", Lee et al , U S Patent Application Ser No 1 1/080294, filed Mar 15, 2005, published as U S Patent Application Publication No 20060086596 on Apr 27, 2006, Oguro et al , U S Pat No 6,762,210, filed on Feb 19, 1999, entitled "Process for Producing Polymeric Actuators", Oguro et al , U S Pat No 7, 169,822, filed Jun 14, 2004, entitled "Polymeric Actuator", Pei et al , U S Pat No 7,224, 106, filed Jan 18, 2006, entitled "Electroactive polymers", U S Pat No 6,475,639, filed on Feb 26, 1999 entitled "Ionic Polymer Sensors and Actuators", and Arora, S , Ghosh, T , and Muth, J , "Dielectric elastomer based prototype fiber actuators". Sensors and Actuators A Physical. 136 l , pp 321 -328 (May 2007) All of the above references are hereby incorporated in their entireties by reference thereto
[00395] A basic construct for a variable lens element is shown in Figs 89 and 90, in which the fluid is substantially optically clear, and at least a portion of the deformable membrane is also substantially optically clear The membrane includes first and second surfaces, at least one of which is facing, and may be in direct contact with, the working fluid
[00396] In Fig 89 the membrane is flat, while in Fig 90 the membrane has assumed a convex shape The convex shape may result from positive pressure being exerted from the working fluid, and this pressure could result from reducing the volume of the fluid chamber, or by additional fluid being introduced into the fluid chamber However, it may also be accomplished by pressing the membrane, or a portion of the membrane, in the direction of the fluid, with the pressure being exerted against the side of the membrane facing away form the working fluid, as shown in Figs 91 and 92
[00397] Fig 91 shows fluid component 5002 in container 5004, which is in turn in housing 5006 The lens element may further include support or boundary element 5008 It should be noted that all elements present in a given lens system and lens module that he within the desired optical path of the system should be at least substantially optically clear For example, in Fig 91 , deformable member 5010, fluid component 5002, container 5004, and support or boundary element 5008 should all be at least substantially optically clear, in at least a central portion corresponding to at least a portion of the optical path for the lens system
[00398] Deformable member 5010 is adjacent to working fluid component 5002 Force elements 5014 are fixed at lower portions 5016, with upper portions 5018 adjacent pressure element 5020 Pressure element 5020 is in the form of a ring, washer, or similar annular shape, shown here in cross-section Upon actuation, force elements 5014 exert force downward, via portions 5018, on pressure element 5020 Pressure element 5020 presses deformable member 5010 in the direction of working fluid component 5002, resulting in the formation of convex portion 5022, as shown in Fig 93 When force elements 5014 are de-actuated, the elasticity of deformable member 5010, and/or the dynamic of fluid component 5002, will cause the deformable member to return to substantially its pre-actuation shape of Fig 91 This illustration assumes that the deformable member is flat in its default state, and that actuation of the force elements cause it to present a curved surface, but it may readily be appreciated that Fig 92 could represent the default state, with actuation of the force elements producing the configuration of Fig 91
[00399] As previously noted, both surfaces of the deformable member will usually be facing, and often in direct contact with, a fluid For example, one surface will often be in contact with the ambient air The other surface may be in contact with a working liquid, but it is possible to use a gas on both sides In fact, any combination is possible, gas/gas, gas/liquid, liquid/gas, and liquid/liquid However, at least one side of the deformable member will face, or be in contact with, a working fluid, as opposed to, for example, the ambient atmosphere
[00400] The force element introduces force in order to deform the deformable member and to thereby change the focal length and/or the orientation of the optical axis The force element of the present invention may be disposed both symmetrically, and circumferentially, around a central axis of the deformable member In this context, symmetry is not determined by the physical positioning or location of the force element, but by how the force itself is exerted with respect to the deformable member Taking a circular deformable member as an example, a symmetrically disposed force element is one which is capable of either exerting a continuous force around the entire circumference of the deformable member, as represented by the shaded inner annulus in Fig 93, or of exerting discontinuous forces that are regularly spaced around the circumference, as suggested by Figs 94-96 In each of Figs 93-96, 5030 represents the surface of the deformable membrane and shaded area 5032 represents the area on which force is exerted around the circumference of that membrane through the force element (not shown)
[00401 ] The force element may reside inside the lens element, or it may comprise one or more walls of the lens element, or it may reside outside the lens element Combinations of these configurations are also possible Further, "circumferential" refers to the fact that the lens element will have a perimeter that is closed, and which may consist entirely of curves (as in a circle, oval, egg, hourglass, or ellipse) or of line segments (as in a triangle, rectangle, or other regular or irregular polygon) The perimeter may also combine curves and line segments
[00402] The lens may alternatively be a single component, rather than a combination of a working fluid and a deformable member In this embodiment the lens is a deformable, optionally elastically deformable, solid, such as a silicone that is optically clear in at least a portion This embodiment is represented in Figs 97-98 Fig 97 depicts a disc of deformable solid 5040, on which rests a washer-shaped pressure element 5042 In Fig 98, pressure has been exerted on pressure element 5042, causing it to move downward Solid 5040 is not free to simply move proportionally away from the direction of the force - for example, it may rest on a glass surface, and be circumferentially constrained by a side wall - and therefore pressure element 5042 presses down into solid 5040, causing the formation of convex surface 5044
[00403] Figs 97 and 98 are illustrative only, and several alternatives are available For example, rather than being pushed downward, pressure element 5042 may be pulled downward by a force acting from below the level of the deformable member Or, pressure element 2 may surround at least a portion of the circumference of solid 1 and then have its diameter reduced in a compressing or squeezing action to create convex portion 5044 By "at least a portion of the circumference of solid 5040", it is meant that pressure element 5042 would extend completely around the circumference, but may have a height less than that of the outer wall of solid 5040, although this is possible
[00404] For example, Fig 99 shows an embodiment in which a relatively narrow, washer-shaped pressure element 5046 extends around the outer wall of the deformable member, and Fig 100 shows an embodiment in which a relatively broad washer-shaped pressure element 5048 is used
[00405] The following discussion refers to Fig 101 , showing lens element 5100 having piston 5102, fluid 5104, and deformable member 5108, shown in three configurations, flat (4a), convex (4b), and concave (4c) In this construct the initial mechanical force is generated when piston 5102 starts to move in response to electrical energy being supplied to a motor driving the piston (not shown) The mechanical energy of the moving piston is then transmitted to the fluid with which it is in direct contact, transmitting force from the piston to the fluid immediately surrounding the piston head This force is in turn propagated through the fluid until it reaches the deformable membrane Thus, in this type of system the mechanical force causing deformation of the membrane propagates through three fluid zones a first zone proximal to where the mechanical force is first generated, represented in this example as Ft , a second zone, represented in this example as F2, through which the force is transmitted through the fluid (as shown by arrows) from the piston to the membrane, and a third zone where the fluid contacts the deformable membrane, shown as F3
[00406] Fig 101 is representative of lens elements in which the deforming force changes direction between the force element and the deformable member The initial force propagates from the face of 5102 to the right as presented, but must transition from a lateral to a longitudinal direction in traversing the fluid chamber between the face of the piston and the surface of deformable member 5108
[00407] Another configuration in which the force changes direction involves use of a secondary fluid container that is used to add fluid to, or draw fluid from, the primary fluid container in order to affect the shape of the membrane An example is shown in Fig 102, which is identical to Fig 101 but for the addition of sealing member 51 10 which incorporates a 2-way, self-sealing valve (not shown), dividing the fluid volume into primary fluid container 51 12 and secondary fluid container 51 14 Motion of piston 5102 causes movement of fluid between the primary and secondary containers, and the fluid is added to or withdrawn from the primary container radial to the deformable membrane
[00408] An analogous configuration is shown in Fig 103, showing deformable membrane 5 120, primary fluid container 5124, and secondary fluid container 5126, which interfaces with primary fluid container 5124 through interface 5122 containing a sealable 2-way valve (not shown) A motive force, such as a piston, acts to push fluid from secondary container 5126 into primary container 5124, and/or to pull fluid from primary container 5124 into secondary container 5126, thereby deforming the deformable membrane Here again the force deforming the membrane has an initial component within secondary container 5126 and within primary container 5124 adjacent interface 5122 that is lateral or transverse to the deformable membrane, with the force then being translated into a direction longitudinal to the deformable membrane as it travels or is propagated through primary container 5124 from the interface to the membrane
[00409] In an alternative approach the force deforming the membrane may be primarily or entirely longitudinal to the membrane as it propagates from the initial point of generation to the membrane In Figs 101 and 102, this may be visualized by taking the horizontal (as shown) portion of the lens element, rotating it 90° in a counterclockwise direction, and aligning it so that at least the valve communicates directly with the primary fluid container at interface 5122 However, this must be accomplished in a manner that does not obstruct the optical axis, as by making the secondary container smaller in diameter or cross-section than the face of the primary container with which it connects, and offsetting the secondary container from the optical axis of the primary container, as seen in Fig 104
[00410] When one considers the practical aspects of manufacturing such a lens element and fitting it within a mount or housing for use in a device, the irregular shape of a lens element such as shown in Fig 104 would not be optimal, providing for the secondary container would likely mean additional machining, a relatively complicated placement of the piston or other motive force used to move fluid between the primary and secondary containers, and so on This configuration could also render the secondary container more vulnerable to damage, both in assembly and during use, depending on the amount of force that the secondary container could bear before being shifted, thereby damaging or breaking the interface with the primary container Also, with regard to Figs 101 and 102, it is not apparent that one could simply rotate the horizontal portion of the lens element to come into longitudinal alignment with the membrane, as the piston element would then at least partially, if not totally, obstruct the optical axis
[0041 1 ] The path followed by the force from its inception by the force element to its absorption by the deformable membrane may be transverse to deformable membrane, longitudinal to the deformal membrane, or a combination of both In this context, the terms "transverse" and "longitudinal" are used with reference to a line passing through and perpendicular to the surface of the deformable membrane when that surface is flat (or, if is never flat, perpendicular to its surface at the central point or axis), with a "transverse" force being perpendicular or substantially perpendicular to such a line, and a longitudinal force being parallel or substantially parallel to such a line Alternatively, given a deformable membrane having a uniform curvature, the terms "transverse" and "longitudinal" are used with reference to the optical axis, with a "transverse" force being perpendicular or substantially perpendicular to the optical axis, and a longitudinal force being parallel or substantially parallel to the optical axis An illustrative example of such forces in shown in Fig 105, depicting the circular surface 5150 of a cylindrical deformable membrane, center line 5152 (which may be considered the optical axis when deformable membrane 5150 has a uniform curvature), transverse forces T, and longitudinal forces L In this representation, the transverse forces T would be radial to the circular surface of the deformable membrane, and the longitudinal forces L would be parallel or substantially parallel to the center line or optical axis, which is normal to the circle and passes through its center Those of skill in the art will readily recognize that any force applied to the surface of the deformable member that is not purely transverse or longitudinal to that surface may be decomposed into transverse and longitudinal components [00412] In the embodiment using a pressure element contacting the deformable member to transmit force from the force element, the size, shape, and composition of the pressure element may be changed to accomplish various goals, including chemical compatibility with the material of the surface of the deformable member with which it is in contact, obtaining a minimal coefficient of friction at the points of contact between the pressure element and the deformable member to mimm^e abrasion, cost, ease of machining, and precision of machining It is also preferable that none of the surfaces of the pressure element contacting the deformable member be a sharp edge, that is, none of the surfaces should be an edge that may be represented by a line, or that results from the direct intersection of two planar surfaces, as in the edge of a rectangular solid Rather, all surfaces of the pressure element contacting the deformable member should be curved, whether by rounding what would otherwise be a sharp edge between two planar surfaces, as represented in Fig 106, showing, in cross sectional detail of pressure element 5200, planar surface 5202, planar surface 5204, and curved intersecting surface area 5206, or by providing the pressure element overall with a shape having a cross section that is in the shape of a circle, oval, egg, or ellipse, as represented in Figs 107, 108, 109, and 1 10 respectively, or other shape having a cross section with no straight lines
[00413] The sue and shape may also be varied to affect the speed and magnitude of response of the deformable membrane to changes in the relationship of these two components For example, Figs 1 1 1 and 1 12 show use of a relatively narrow and relatively wide pressure element 5302, respectively, shown here in a ring or washer configuration Because the pressure element in Fig 1 12 covers more surface area of the deformable membrane than that in Fig 1 1 1 , and because the membrane is deformable, an equal amount of downward motion of the pressure elements in Figs 1 1 1 and 1 12 will result in the pressure element of Fig 1 12 producing a significantly more convex surface, as shown in Figs 1 13 and 1 14 Alternatively, if it is desired to produce the same amount of curvature or convexity with both pressure elements, then the pressure element of Fig 1 12 can be moved a smaller distance than the pressure element shown in Fig 1 1 1 to accomplish the same effect
[00414] Selection of heavier or lighter materials to make the ring may also affect how responsive the lens module is to input of a given amount of force, as they may respond differently to the application of force than lighter materials Similarly, the viscosity and/or specific weight of the optical fluid component may affect the responsiveness of the system to the input of a given amount of force
[00415] While several of the embodiments discussed herein depict the force element acting in a direction primarily longitudinal to the deformable membrane, it is also possible for the force element to act in a direction primarily tangential or radial to the deformable membrane For example, rather than using a pressure element to press down on a flat deformable member to create a convex surface, it is possible to construct the deformable member with a surface that is convex without any force applied, and to then exert force radially outward on the deformable member in order to decrease the convexity of the surface, as shown in Figs 1 15 and 1 16 Fig 1 15 shows convex surface 5312 of the lens element, which is convex without any force being exerted by pressure element 5316 When actuated, pressure element 5304 moves or expands radially outward stretching the upper surface of the lens element and flattening convex surface 5312 as shown in Fig 1 16
[00416] The linkage between pressure element 5316 and the deformable element needed to accomplish this approach could be accomplished in a number of ways For example, pressure ring 5316 may be adhered to the surface of the deformable element, or placed inside the deformable element so that radial outward movement of the pressure element expands the diameter of the deformable member as shown The pressure element could reside in a groove in the outer circumference of the upper surface of the deformable member, held in place by a rigid and at least partially electrically conductive ring or washer-shaped element surrounding the convex portion 5312, with the ring or washer-shaped element used as an electrical contact, or as a conduit for one or more electrical connections, to energize the pressure element
[00417] In another embodiment, the pressure element may exert at least partially opposing forces on the deformable element This can be used, for example, to reduce the physical motion needed to produce a given change in deformation, or to increase the speed with which a given deformation can be achieved A simplified version of such a configuration is shown in Fig 1 17, including lens element 5400 comprising deformable member 5402, deformable member housing element 5418, pressure element 5408, and pivot point 5410 The deformable member may be integral with the housing or attached to it, for example, the surface of the deformable member may be a membrane whose edge is adhered, clamped, sealed, or otherwise affixed to the housing, as by constructing the housing from upper and lower portions and sealing edge portion 5412 of membrane 5402 between upper portion 5416 and lower portion 5418 as depicted in Fig 1 18
[00418] In this configuration one force element is so arranged that its motion will press generally downward on the deformable membrane, as suggested by upper curved arrows in Fig 1 17, imparting a general downward force to the deformable membrane as shown by the angled straight arrows Another force element is configured so that its motion will cause the lower edge of the deformable membrane to move radially outward, as suggested by the lower curved arrows and straight horizontal arrows These two motions will have a cumulative effect of flattening the deformable membrane more rapidly than would either force acting alone This may be accomplished using a single force element, as shown, in a rocker configuration, where the force element pivots around pivot point 5410, pushing the upper arm downwardly on the deformable element while the lower arm draws the outer edge of the deformable membrane radially outward Alternatively, the force element may be provided as two or more separately acting components, which would allow greater control over the motion If, for example, the upper and lower arms of the force element shown in Fig 1 17 were separately actuable, the lens element would have three potential levels of response in reaction to a given voltage being applied, one for voltage applied only to the upper force element, a second for voltage applied only to the lower, and a third for voltage applied to both
[00419] As noted elsewhere herein, the force element may be a unitary element extending completely around the periphery or circumference of the deformable member, or may be plural separate or discrete elements Fig 1 19 is a simplified representation of one embodiment of a unitary element seen from above the lens element and looking down along the optical axis Here 5430 is the upper surface of the deformable membrane, and 5432 represents the physical location of an annular force element around the periphery of the deformable membrane Shadowed area 5434 represents that area of the surface of the deformable membrane that is directly contacted by or receives force from the pressure element, such as through super positioning of an upper portion of the pressure element with the deformable membrane surface (not shown) [00420] Fig 120 shows another embodiment, in which the force element comprises several discrete force elements 5450 around the circumference of spherical deformable member 5454, exerting force over a continuous annular area 5460 of the outer surface of the deformable member This may be accomplished by appropriately configuring the portion of each discrete force element that contacts the surface of the deformable member, as in each such portion being in the form of an arc of a circle concentric with the deformable member and sized such that there is little or no gap between them It may be necessary in this configuration to allow a small gap between each such arcuate contact portion when they are in a position of merely resting on the deformable membrane without exerting downward force, so that when they are actuated and press down into the deformable member, they do not interfere with each other Alternatively, the contact portions may each be relatively small, but, instead of contacting the deformable member directly, they contact a pressure element as described elsewhere herein, and the pressure element serves to transfer the relatively point-type force received from each force element into a relatively continuous force exerted around the circumference or periphery of the deformable member
[00421 ] It should be noted that many if not all of the force element configurations described herein may be adapted to placement internal to the lens element or deformable member Where the lens element contains an optical fluid component, such placement may require, or be facilitated by, use of a non-conductive optical fluid, such as a mineral or silicon oil Further, as with the dual-acting configurations discussed in relation to Fig 1 17 a combination of both internal and external force elements may be used, which may be so configured as to act independently of each other, simultaneously with each other, or selectably in either mode
[00422] Use of a unitary element may facilitate a more uniform or symmetrical response of the deformable member to force, while use of plural discrete elements may produce a more asymmetrical deformation of the deformable element, depending in part on the flexibility or stiffness of the deformable element A relatively stiff deformable element will tend to transmit force applied at one point of the element more widely and uniformly to adjacent areas than will a relatively flexible deformable element For example, where the goal is a uniform and symmetrical response over the entire deformable membrane, use of a relatively flexible deformable material to create the deformable membrane will tend to favor use of a unitary force element, such as one having a ring or washer configuration, capable of applying force uniformly around the circumference or periphery of the deformable element, whereas use of a relatively stiff deformable material to create the deformable membrane will tend to enable use of plural forced elements that, even in combined use, will exert force on discontinuous areas of the deformable membrane
[00423] In addition to the actuator polymers discussed herein, other constructs or devices may be used as force elements Piezoelectric elements may be used to generate motive force for transmittal, whether hydraulically through a liquid, pneumatically through a gas, or mechanically through one or more force transmission elements such as a push ring A voice coil construct may be used to generate and alter a magnetic field that will act on a magnetic component of the lens element in order to deform the deformable element Fig 121 shows a lens element having fluid component 5501 in container 5502, which is in turn in housing 5503 Housing 5503 is surrounded by voice coil 5504, which acts on magnetic pressure elements 5505 to deform deformable membrane 5506 [00424] In the embodiment of Fig 121 , the pressure element is magnetic, and a voice coil may be positioned so that when the coil is activated, the pressure element deforms the deformable element as it is drawn towards, or repelled away from, the magnetic field generated by the voice coil A lens element incorporating a voice coil has several configuration parameters, for example, a the voice coil may be fixed or moveable, b the magnetic field produced by the voice coil may move the coil itself, or another part of the lens element that is magnetic, c the element that moves in response to the magnetic field generated by the voice coil, whether the coil itself or some other component, may act, directly or through one or more linkages, on the deformable membrane (such as via a pressure element situated on top of the deformable membrane), or on the optical fluid component, which in turn acts on the deformable membrane, d the voice coil may be positioned above, level with, or below the deformable member, including below the optical fluid component, e the voice coil may be positioned exterior to the housing as shown in Fig 121 , interior to the housing but exterior to the optical fluid component as shown in Fig 122, or interior to the optical fluid component as shown in Fig 123, f the voice coil may be attached to the bottom of the housing containing the optical fluid, such that movement of the voice coil compresses or extends the fluid container, thereby deforming the deformable member in either the convex or concave direction This embodiment is shown in Fig 124, showing a lens element having fluid component 5501 in container 5502 with deformable member 5505, container 5502 is in turn in housing 5503 Voice coil 5504 is attached to the bottom of container 5502, which is flexible in at least the longitudinal direction (for example, the side wall is elastic or pleated), and the lower portion of voice coil 5504 is fixed to another housing element (not shown) Use of fixed magnets and application of voltage to the voice coil in order to draw the voice coil downwards will result in a concave deformable member 5506a as shown in Fig 125, while driving the voice coil upwards will result in the convex deformable member 5506b as shown in Fig 126
[00425] Alternatively, one may envision use of an optical fluid component that is a magneto-optical fluid, that is, an optical fluid that is also magnetically responsive If the walls of container 5502 were sufficiently elastic, and/or configured for extension and compression (as by being pleated such as in an accordion shape), a voice coil and magnets could be positioned to effect extension or compression of the container in response to changes in magnetic field, with such movement of the container effecting changes in the deformable member
[00426] The voice coil may be, for example, a single or double voice coil It may be positioned above, at, or below the level of the deformable member, and may interact with one or more fixed magnets positioned above and/or below the level of the voice coil The voice coil may be mechanically linked to the deformable member and/or the housing or container for the optical fluid, such that movement of the voice coil effects deformation of the deformable member Alternatively, the voice coil may remain relatively fixed, and deformation of the deformable member may be accomplished by interaction of the magnetic field produced by the voice coil with a magnetic component on one more portions of the lens module, such as a magnetic pressure element or magnetic rocker arm
[00427] The present invention may also be discussed in the context of the following equations, sometimes referred to as the lens maker's equations
Figure imgf000087_0001
Thick-lens focal length equation Thin-lens focal length equation
In the equations,
/is the focal length of the lens,
N is the refractive index of the lens material,
Rι is the radius of curvature of the lens surface closest to the light source,
R2 is the radius of curvature of the lens surface farthest from the light source, and
t is the center thickness of the lens (the distance along the lens axis between the two surface vertices)
[00428] With reference to the above equations, the variable lens of the present invention makes it possible to vary f, the focal length, by changing either or both of R l and R2 In those embodiments where one side of the lens element remains flat, such as where a glass or plastic plate or other boundary layer is used to bound one side of the lens, R2 becomes infinity (the radius of curvature of a plane), and hence the parameter J_
D
2 approaches zero It is also a characteristic of the variable lens of the present invention that it enable use if a unitary lens element, whether of the deformable solid or fluid/deformable member configuration, in which center thickness t of the lens is varied concurrently with changes in Rl and/or R2
[00429] As noted earlier, there may be situations where the goal is to correct or reduce certain types of aberrations, and in this regard it is possible to vary the thickness and/or micro-topology of the deformable member over the deformation area, yielding a structure having aspheric attributes while retaining the variability otherwise enabled by the present invention This variation of surface structure may be carried out in view of the directions and degrees of deformation the deformable member is expected to encounter in use, and may also be used to correct for any non-uniform thinning of the deformable member that may take place during use For example, assuming that the edge portions or regions of the deformable member are fixed and only the interior portion undergoes deformation, it may be that the central part of the interior region will experience greater thinning than the adjacent regions as the deformable member is deformed from a relatively flat or level configuration to a convex or concave configuration It may be desirable to use this phenomenon, but it may instead be desirable to minimize or eliminate it This could be done by simply making the profile of the deformable member progress from relatively thinner at the edges to relatively thinner in the center, so that the two regions equalize in thickness when deformed, or, it may be possible to design or affect the microstructure of the deformable membrane so that the optical properties of the deformable member remain proportionately constant as it changes from flat to convex to concave [00430] Both the deformable solid lens element, and the lens element combining a fluid with a deformable member, may be deformable in use on both sides or surfaces of the lens, as shown in Figs 127 and 128 With the deformable solid lens element of Fig 127, the 'lower' surface 5602b of the deformable solid 5601 may be supported by a rigid boundary element 5603 (shown in cross-section only) having central aperture region 5604 (shown as the dotted line portion), allowing lower surface 5602b to change shape in response to force from the force element For example, the lower surface 5602b, which is convex as shown, may become more convex in response to force exerted by a force element on a pressure element (not shown) contacting the periphery of upper surface 5602a and which is pressing down and/or inward on the deformable solid Depending on how deformable or elastic the lower surface 5602b is, the size and/or shape of the aperture may be such that the lower surface is substantially planar in the absence of any force input from the force element Lower surface 5602b may also be separately controlled by an additional force element, with separate force elements capable of acting on the upper and lower surfaces independently and/or in combination Alternatively, rigid boundary element 5603 may be solid, that is, not have a central aperture, and would thereby maintain lower surface 5602b in a predetermined configuration, which may be planar, convex, or concave, and which would not change in response to force provided by the force element
[00431 ] Both the deformable solid lens element, and the lens element combining a fluid with a deformable member, may be deformable in use on both sides or surfaces of the lens, as shown in Figs 127 and 128 With the deformable solid lens element of Fig 127, the 'lower' surface 5602b of the deformable solid 5601 may be supported by a rigid boundary element 5603 (shown in cross-section only) having central aperture region 5604 (shown as the dotted line portion), allowing lower surface 5602b to change shape in response to force from the force element For example, the lower surface 5602b, which is convex as shown, may become more convex in response to force exerted by a force element on a pressure element (not shown) contacting the periphery of upper surface 5602a and which is pressing down and/or inward on the deformable solid Depending on how deformable or elastic the lower surface 5602b is, the size and/or shape of the aperture may be such that the lower surface is substantially planar in the absence of any force input from the force element Lower surface 5602b may also be separately controlled by an additional force element, with separate force elements capable of acting on the upper and lower surfaces independently and/or in combination Alternatively, rigid boundary element 5603 may be solid, that is, not have a central aperture, and would thereby maintain lower surface 5602b in a predetermined configuration, which may be planar, convex, or concave, and which would not change in response to force provided by the force element
[00432] Similarly, the lower surface 5602b of the variable lens element in Fig 128 may be an additional deformable member rather than being a rigid boundary element, and may then function similarly to the upper deformable surface 5602a, responding to a force element that is the same as, or in addition to, the force element used to affect the shape of upper surface 5602a Similarly to the deformable solid configuration discussed in the preceding paragraph, lower deformable surface 5602b may be separately controlled by an additional force element, with separate force elements capable of acting on the upper and lower surfaces independently and in combination Alternatively, lower deformable surface 5602b may be bounded or constrained by a rigid boundary element (not shown) that maintains lower surface 5602b in a predetermined configuration, which may be planar, convex, or concave, and which would not change in response to force provided by the force element [00433] As a further alternative, the rigid boundary element itself may be provided in any lens shape, such as convex, bi-convex, plano-convex, concave, bi-concave, plano-concave, convex-concave, or in the shape of a meniscus Thus, with reference to Fig 130, the lens element may include housing 5650 and optional boundary element 5654 Either or both of housing 5650 and boundary element 5654 may be provided in any lens shape, including those listed above, in at least that region of each corresponding to the optical path of the lens element
[00434] The boundary element itself may be rigid as previously described, such as glass or plastic, or deformable, such as an elastomer When it is desired that the boundary element not undergo any deformation as a result of deforming force being applied to the lens element, it is sufficient if the elasticity of the boundary element is such that the boundary element will not deform in response to the force or energy that will be communicated to it when the lens element is at maximum deformation For example, where the lens module includes a lens element and force element, with the lens element comprising a fluid and a deformable membrane with the fluid entrapped between the boundary element and the membrane, and, a pressure element is used to deform the deformable membrane, if it is desired that the boundary element not deform, then it should be sufficiently rigid to remain planar when the pressure element is exerting maximum pressure on the deformable membrane In other words, when it is desired that the boundary element not deform during operation of the lens module, it is necessary only that the boundary element not deform under such conditions, and not that it be completely rigid or incapable or deforming
[00435] As stated, glass may be used as the boundary element, and a variety of optical glass materials are commercially available, including, for example, Corning® EAGLE2000™ Display Grade glass, available from Corning Display Technologies, Corning, New York USA, and N-BK.7 glass, available from Schott North America lnc , Duryea, Pennsylvania USA The boundary element may be any suitable thickness, including from about 0 1 mm to about 1 mm, for example, 0 2, 0 3, or 0 4 mm
[00436] It should also be noted that, in order to protect against possible changes in optical properties resulting from fatigue of the deformable member or other factors, it may be desirable to incorporate various calibration routines or capabilities into a device utilizing the lens element, such as an automatic start-up calibration routine, and/or an on-demand or user-initiated calibration routine
[00437] A calibration process may be useful for calibrating an apparatus embodying features of the invention A calibration can be initiated by initializing the system, including performing all power-on-sequence tests to assure that the system components are operating properly A test target bearing a pattern or encoded symbol is positioned at a first test position When in the first test position, the target will in general be at defined distance and orientation relative to the hand held reader comprising a variable lens A variable lens control signal (which in some embodiments is a voltage) is adjusted to obtain an acceptable, and preferably an optimal, focus condition for the target The distance and orientation of the target and the variable lens control signal parameters (for example magnitudes and signs of voltages, timing features of the signal such as pulse duration, transition time and repetition rate) are recorded for future use in a non-volatile memory, for example in a table [00438] One can iteratively repeat the process steps of locating the target at a new location and orientation, controlling the variable lens control signal applied to the variable lens to obtain a satisfactory, and preferably optimal, focus, and recording in a memory the information about the target location and orientation and the variable lens control signal parameters, so as to provide a more complete and detailed set of calibration parameters The number of iterations is limited only by the amount of time and effort one wishes to expend performing calibration steps, and the amount of memory available for recording the calibration parameters observed The information obtained in calibration tests can be used when operating the corresponding imager (or in some instances, another imager of similar type) either by using the calibration information as an initial setting for operation in a closed loop mode, or as fixed operating conditions for discrete points in an open loop operating mode
[00439] The current invention uses the principle of altering the interface shape between two fluids and provides the ability to control an optical tilt of the fluid interface to adjust an exit optical axis angle or direction relative to the variable lens One application of such adjustment of the exit optical axis angle is to provide a mechanism and method to compensate for the angular movement caused by hand-jittering or hand motion The present invention therefore also deals with the deleterious effects of image smear caused by hand jittering or hand motion in a hand held device, including an imager or reader Image smear has been one of the major sources for image quality degradation Image smear and similar degradation mechanisms cause a reduced decode rate in a barcode reading application or a reduced contrast and a blurry image in an image capturing application In some instances, hand jitter or hand motion can cause image degradation that may be severe enough to prevent the image from being processed correctly
[00440] In the current invention, a variable lens provided with additional components to counteract involuntary motions ("an anti-hand-jittering variable lens") may be used to combine the auto-focusing and variable angle prism functionalities used in the prior art (such as represented in U S Patent No 6,734,903 to Takeda, et al and Japanese Patent Laid-Open No 2- 12518, into a single low cost component that has fewer moving parts and provides fast response time
[00441 ] Fig 135 is a schematic diagram 6500 showing the relationships between a variable lens and various components that allow adjustment of the optical axis direction The optical axis control system comprises a horizontal angular velocity sensor 6510, a control module 6512 to generate horizontal tilt voltage dh, a vertical angular velocity sensor 6520, a control module 6522 to generate vertical tilt voltage dv, an auto- focusing control module 6530 to generate a focusing voltage Vf, a distributor module 6540 to synthesize the control voltages to control the variable lens module 6400 to accommodate or to correct for hand jittering Alternately when the axis of the optical system changes orientation, the image on the image sensor will move The processor can extract the magnitude and direction of motion of the object that was not expected to move This can be used as input to the correction circuit
[00442] In some embodiments, the angular velocity sensors 6510 and 6520 are commercially available low cost solid-state gyτo-on-a-chιp products, such as GyroChips manufactured by BEI Technologies, Inc , One Post Street, Suite 2500 San Francisco, CA 94104 The GyroChip comprises a one piece, quartz micromachined inertial sensing element to measure angular rotational velocity U S Patent No 5,396,144 describes a rotation rate sensor comprising a double ended tuning fork made from a piezoelectric material such as quartz These sensors produce a signal output proportional to the rate of rotation sensed The quartz inertial sensors are micromachined using photolithographic processes, and are at the forefront of MEMS (Micro Electro- Mechanical Systems) technology These processes are similar to those used to produce millions of digital quartz wristwatches each year The use of piezoelectric quartz material simplifies the sensing element, resulting in exceptional stability over temperature and time, and increased reliability and durability
[00443] Fig 136 is a schematic diagram showing the relationship between a variable lens 6700 and a pair of angular velocity sensors In a preferred embodiment, two of the angular velocity sensors 6710, 6720 can be integrated with the variable lens 6700 to form an integrated module 6730 The angular velocity sensors 6710 and 6720 are arranged in an orthogonal relationship to detect two orthogonal angular velocities In some embodiments, the entire control circuitry as shown in Fig 135 can also be integrated into the module 6730 An advantage of this embodiment is ease of mounting the module 6730 No vertical or horizontal alignments are required The module will automatically adjust the lens tilt angle according to the output voltages dh and dv provided by the angular velocity sensors 6710 and 6720
[00444] In another embodiment, apparatus and methods are provided to counteract changes in the environment that surrounds an apparatus comprising a variable lens In one embodiment, the apparatus comprises a temperature sensor with a feed back (or feed forward) control circuit, to provide correction to the variable lens operating signal as the temperature of the variable lens (or of its environment) is observed to change In another embodiment, the apparatus comprises a pressure sensor with a feed back (or feed forward) control circuit, to provide correction to the variable lens operating signal as the pressure in the ambient environment is observed to change This may, for example, facilitate operation of the variable lens under conditions of reduced pressure, such as at high altitudes (or even in vacuum), or under conditions of increased pressure, such as in pressure chambers or underwater
[00445] In yet another embodiment, a system comprising a variable lens additionally comprises a non- variable lens component configured to correct one or more specific limitations or imperfections of the variable lens, such as correcting for color, spherical, coma, or other aberrations of the variable lens itself or of the variable lens in conjunction with one or more other optical components By way of example, a variable lens may exhibit dispersive behavior or color error In one embodiment, a second optical element is added that provides dispersion of the sign opposite to that exhibited by the variable lens, so as to correct the dispersive error introduced by the variable lens In one embodiment, the dispersive element is a diffraction element, such as an embossed grating or an embossed diffractive element As will be understood, different optical materials have different dispersive characteristics, for example, two glass compositions can have different dispersion, or a composition of glass and a plastic material can have different dispersion In the present invention, a material having a suitable dispersive characteristic, or one made to have suitable dispersive characteristics by controlling the geometry of the material, such as in a grating or other diffractive element, can be used to correct the errors attributable to the variable lens and/or the other components in an optical train
[00446] Applications for variable lenses include their use in one or more types of camera, such as cameras in cell phones, use in higher quality digital cameras such as those having a high powered zoom lens, and use in cameras that can provide auto focus, and pan, tilt, and zoom ("PTZ") Panning is moving a camera in a sweeping movement, typically horizontally from side to side Tilting is a vertical camera movement, e g in a direction orthogonal to panning Commercially available PTZ video and digital cameras that use mechanical redirection of the camera and refocusing of its lens are well known, and are often used in surveillance In order to accomplish such features as tilt or pan, one needs to reorient the interface between two optically dissimilar fluids so that the optical axis is relocated from its original direction horizontally (pan) or is relocated from its original direction vertically (tilt) With a variable lens, both relocations can be accomplished in a single redirection of the optical axis at an angle to both the horizontal and vertical directions simultaneously Such redirections are readily computed using spherical geometry coordinates, but can also be computed in any coordinate system, including using projection from three dimensions to two dimensions, for example as is commonly done in x-ray crystallography as an example One method to accomplish all of auto focus, pan, tilt, and zoom is to apply several features in a single device
[00447] By having more than one lens element configured as a variable lens, for example a lens triplet, the optical aberrations present in a single element can be reduced for the assemblage of lenses and this would result in a higher quality optical image The techniques for optimizing a triplet are well known in the lens design art However, it is typically the case that any given lens is optimized for a given focal length system Typically, if a lens is optimized for one combination of optical elements, it is not optimally configured when one of the lens surfaces is changed as would happen when a single fluid element is operated to change an optical parameter, such as focal length By adding a second variable lens, the combination of the first lens and the second lens can be optimized to minimize total system aberrations For different settings of the first lens, corresponding changes in the settings of the second lens can be made to obtain an optimal combination These optimized relationships between the two variable lens surfaces curvatures, i e surface optical power, and thus also the control voltages, can be contained for example in a table that is recorded in a machine readable memory Thus for any given setting of desired system optical power, the appropriate drive voltages for the two variable lenses can be developed, and applied in accordance with the recorded values Where desirable or advantageous, the fineness of the table resolution may be increased through use of linear or higher order interpolation and extrapolation
[00448] The lens module of the present invention may be incorporated into a wide variety of devices The devices may be stationary/fixed or portable, and include data collection devices such as bar code scanners and portable data terminals, portable digital assistants, portable computers, including notebooks and laptops, cordless and cellular telephones, including camera cell phones, and smart phones, the latter including hand held devices which combine wireless phone capabilities with other functions such as network connectivity (whether Internet, WLAN, WMAN, WWAN, or other), the ability to play music or video files, the ability to display images, the ability to send and/or receive e-mail, and so on These products are changing rapidly, examples of current such devices include the Palm® Treo®, the BlackBerry® smart phones (Curve, 8800, Pearl, 8700 Series, and so on), the Helio™ Ocean, Heat, and Drift devices, and the Apple® iPhone™
[00449] [End of text section substantially as presented in U S Patent Application No 60/961 ,036]
[00450] A small sample of systems methods and apparatus that are described herein is as follows A l An apparatus for use in a lens assembly, said apparatus comprising
a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting at least one of a pushing force or a pulling force to said deformable surface
A2 The apparatus of claim A l , wherein said force imparting structural member is adapted to impart a force to said deformable surface at a plurality of force impartation points formed in a ring pattern spaced apart from and peripherally disposed about said axis
A3 The apparatus of claim A l , wherein said force imparting structural member is adapted to impart a force to said deformable surface at a plurality of force impartation points formed in an area pattern about said axis
A4 The apparatus of claim A l , wherein said force imparting structural member is an actuator
A5 The apparatus of claim A l , wherein said force imparting structural member is a structural member that transmits force generated by an actuator
A6 The apparatus of claim A l , wherein said force imparting structural member imparts a force generally in a direction of said axis
A7 The apparatus of claim A l , wherein said deformable surface partially defines a cavity that holds focus fluid
A8 The apparatus of claim A l , wherein a major body of said deformable lens element comprises a resiliently deformable material member, and wherein said deformable lens element is devoid of a focus fluid
A9 The apparatus of claim A l , wherein said apparatus is adapted so that said structural member is capable of imparting both of said pushing force and said pulling force to said deformable surface
A l O The apparatus of claim A l , wherein said apparatus is adapted so that said structural member is capable of imparting a pulling force to said deformable surface
B l An apparatus for use in a lens assembly, said apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting a pushing force to said deformable surface resulting in a thickness of said deformable lens member along a plurality of imaginary lines running in parallel with said imaging axis decreasing B2 The apparatus of claim Bl , wherein said apparatus is adapted so that when said pushing force is imparted to said deformable surface, said deformable surface bulges outward in an area of said deformable surface about said axis
B3 The apparatus of claim B I , wherein said apparatus is adapted so that said plurality of imaginary lines along which said thickness of said deformable lens element decreases do not include a plurality of imaginary lines running parallel with said imaging axis and intersecting said deformable surface within an area delimited by a ring shaped pattern spaced apart from and peripherally disposed about said axis
B4 The apparatus of claim B l , wherein said plurality of imaginary lines include imaginary lines disposed about said axis
Cl An apparatus for use in a lens assembly, said apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting one or more of the following to said deformable surface
(a) a pushing force resulting in the deformable surface bulging outward in an area of said deformable surface about said axis, and
(b) a pulling force resulting in a shape of said deformable surface changing
C2 The apparatus of claim C l , wherein said deformable surface is capable of a concave configuration and wherein said pulling force increases a concavity of said deformable surface
C3 The apparatus of claim C l , wherein said deformable surface is capable of a convex configuration and wherein said pushing force increases a convexity of said deformable surface
C4 The apparatus of claim C l , wherein said apparatus is adapted so that said force imparting member is capable of imparting each of said pushing force and said pulling force on said deformable surface
C5 The apparatus of claim C l , wherein at least one of said pushing force and said pulling force are generated by an electro-active polymer actuator
C6 The apparatus of claim C l , wherein at least one of said pushing force and said pulling force is imparted in a direction generally in a direction of said axis
C7 The apparatus of claim C l , wherein a major body of said deformable lens member comprises a resiliently deformable material member
C8 The apparatus of claim C l , wherein said deformable surface partially defines a cavity filled with focus fluid C9 The apparatus of claim C l , wherein said pushing force results in a thickness of said deformable lens member decreasing along an imaginary line running in parallel with and being spaced apart from said axis
ClO The apparatus of claim Cl , wherein said pushing force results in a thickness of said deformable lens member decreasing along a plurality of imaginary lines running in parallel with and being spaced apart from said axis, the plurality of imaginary lines being peripherally disposed about said axis
Dl An apparatus for use in a lens assembly, said apparatus comprising a deformable lens member having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting a pushing force to said deformable surface resulting in a thickness of said deformable lens member along said axis decreasing
D2 The apparatus of claim D l , wherein said force imparting member is configured to impart said pushing force to said deformable surface at a plurality of feree impartation points that include an area about said axis, the force imparting member being optically clear for transmittal of image forming light rays
D3 The apparatus of claim D l , wherein said deformable lens member is normally convex in an unstressed state thereof
D4 The apparatus of claim D l , wherein said force imparting structural member imparts a force to said deformable surface at a plurality of points defined substantially over an entire area of said deformable surface
D5 The apparatus of claim D l , wherein a major body of said deformable lens member is provided by a resiliency deformable material member
D6 The apparatus of claim D l , wherein said force is generated by an electro-active polymer actuator having an optically clear area disposed about said axis
D7 The apparatus of claim D l , wherein said force is generated by an electro-active polymer actuator comprising a flexible member substantially conforming to a shape of the deformable surface, the flexible member having an optically clear area disposed about said axis
D8 The apparatus of claim Dl , wherein said apparatus is adapted so that said pushing force is imparted in a direction generally in a direction of said axis
E l A method comprising incorporating a deformable lens element into an optical system, said deformable lens element having a deformable surface, at least part of which transmits image forming light rays, and imparting a force to said deformable surface of said deformable lens element at a plurality of force impartation points of said surface to vary an optical characteristic of said optical system, wherein said imparting step includes the step of utilizing a force imparting structural member for imparting said force
E2 The method of claim El , wherein said imparting step includes the step of utilizing an electro-active polymer actuator
E3 The method of claim E l , wherein said deformable lens element has an axis, and wherein said imparting step includes the step imparting said force generally in the direction of said axis
E4 The method of claim E l , wherein said plurality of force imparting points are defined in a ring pattern on said surface peripherally disposed about and spaced apart from said axis
E5 The method of claim El , wherein said plurality of force imparting points define a two dimensional area about said axis
E7 The method of claim E l , wherein said force is a push force directed toward said deformable lens element
E8 The method of claim El , wherein said force is a pull force directed away from said deformable lens element
Fl A method comprising incorporating a deformable lens element having an axis into an optical system, said deformable lens element having a deformable lens surface at least a part of which transmits image forming light rays, and imparting a pulling force to said deformable surface of said deformable lens element to vary an optical characteristic of said optical system, wherein said imparting step includes the step of imparting said pulling force generally in a direction of said axis
F2 The method of claim Fl , wherein said imparting step includes the step of utilizing an electro-active polymer actuator
F3 The method of claim Fl , wherein said imparting step includes the step of imparting said pulling force at a plurality of points spaced apart from and peripherally disposed about said axis
F4 The method of claim Fl , wherein said imparting step includes the step of utilizing a structural member
G l An optical imaging system comprising a deformable lens element having a deformable surface at least part of which transmits image forming light rays, a force imparting structural member opposing said surface, and wherein said imaging system is adapted so that a force can be imparted by said force imparting structural member at a plurality of force impartation points of said deformable surface of said deformable lens element for varying an optical characteristic of said imaging system G2 The optical imaging system of claim G l , wherein said force impartation points are defined in an area pattern about an axis of said deformable lens element
G3 The optical imaging system of claim G l , wherein said force impartation points are defined in a ring pattern defined at positions spaced apart from and peripherally disposed about said axis
H 1 An optical imaging system comprising a deformable lens element comprising a deformable membrane, a cavity delimited by said deformable membrane, and fluid disposed in said cavity, said fluid having an index of refraction greater than one, said deformable lens element having an axis, and a force imparting structural member capable of contact with said deformable lens element at positions defined circumferentially about said axis, wherein said optical imaging system is configured so that said force imparting structural member can be moved generally in a direction of said axis either toward or away from said deformable lens element so that an optical characteristic of said imaging system vanes with movement of said force imparting structural member
H2 The optical imaging system of claim H l , wherein said force imparting structural member is provided by a ring-shaped pressure element
H3 The optical imaging system of claim H l 1 wherein said force imparting structural member is provided by a plurality of tab-like elements of an electro-active polymer actuator
H4 The optical imaging system of claim H l , wherein said force imparting structural member is provided by a flexible member of an electro-active polymer
11 An optical imaging system comprising a deformable lens element comprising a deformable membrane, a cavity delimited by said deformable membrane, and fluid disposed in said cavity, said fluid having an index of refraction greater than one, said deformable lens element having an axis, a ring-shaped pressure element in contact with said deformable lens element and arranged circumferentially about said axis, and an electro-active polymer actuator mechanically coupled to said ring-shaped pressure element, said optical imaging system being configured so that said electro-active polymer actuator moves said ring-shaped pressure element generally in a direction of said axis so that an optical characteristic of said imaging system varies with movement of said ring-shaped pressure element
12 The optical imaging system of claim I I , wherein said electro-active polymer actuator includes a ring- shaped deformable element comprising a plurality of tab-like elements, said deformable element being circumferentially disposed about said axis, said plurality of tab-like elements engaging said ring shaped pressure element J l An optical imaging system comprising a deformable lens element having an axis, wherein a major body of said deformable lens element is provided by a resiliently deformable member having a hardness measurement of less than Shore A 60, and wherein said imaging system is configured so that a force can be applied to an external surface of said deformable lens for varying an optical characteristic of said imaging system
J2 The optical imaging system of claim J I , wherein said optical imaging system includes an flexible member actuator for imparting said force, said actuator having a flexible member adapted to substantially conform to a shape of said deformable lens element
K l An optical system for use in imaging an object, said system comprising a deformable lens element capable of being deformed wherein said deformable lens element has a deformable surface that faces an exterior of said deformable lens element, said deformable lens element having an axis, wherein said optical system is adapted so that said system can impart a force to said deformable surface generally in a direction of said axis toward said deformable lens element in such manner that an optical property of said deformable lens element is changed by impartation of said force
K2 The optical system of claim K l , wherein said optical system is adapted so that said system imparts said force at a plurality of positions spaced apart from and peripherally disposed about said imaging axis
K3 The optical system of claim Kl , wherein said optical system includes an actuator including an aperture disposed about said axis for imparting said force to said deformable lens element generally in a direction of said axis
Ll An optical system for use in imaging an object, said system comprising a deformable lens element having a deformable lens surface, at least part of which transmits image forming light rays and which faces an exterior of said deformable lens element, said deformable lens surface being one of normally convex or capable of exhibiting a convex curvature, said deformable lens element having an axis, and an actuator for imparting a force to said deformable surface, the actuator having an aperture disposed about said axis, the optical system being adapted so that actuation of said actuator results in a force being imparted to said deformable surface to vary a convexity of said deformable lens element
L2 The optical system of claim L l , wherein said optical system includes a pressure element transferring a force generated by said actuator to said deformable lens element
L3 The optical system of claim L l wherein said deformable lens element is configured so that, for achieving deformation thereof, said deformable lens element is contacted at a plurality of positions spaced apart from and peripherally disposed about said axis L4 The optical system of claim Ll , wherein said optical system includes a force imparting structural member for imparting a force generated by said actuator and for imparting said force generated by said actuator to said deformable surface
L5 The focus apparatus of claim L4, wherein said force imparting structural element is said actuator
M l A hand held data collection terminal comprising a two dimensional image sensor comprising a plurality of pixels formed in a plurality of rows and columns of pixels, an imaging lens assembly comprising a deformable lens element for focusing an image onto said two dimensional image sensor, said imaging lens being adapted so that said deformable lens element can be deformed with use of a force imparting structural member, said imaging lens assembly being adapted so that force can be applied to an external surface of said deformable lens element to vary an optical property of said deformable lens element, said imaging lens setting having a first lens setting at which said deformable lens element is in a first state and a second lens setting at which said deformable lens element is in a second state, and a trigger for activating a trigger signal, said data collection terminal being adapted so that said trigger signal can be maintained in an active state by maintaining said trigger in a depressed position, wherein said data collection terminal is adapted so that responsively to said trigger signal being maintained in said active state, said data collection terminal captures in succession a plurality of frames of image data, each of said plurality of frames of image data representing light incident on said image sensor at an instant in time, wherein said data collection terminal is adapted so that a lens setting of said imaging lens assembly is varied while said trigger signal is maintained in said active state in such manner that said lens assembly is at said first setting for an exposure period corresponding to at least one of said plurality of frames of image data, and said lens assembly is at said second lens setting for an exposure period corresponding to at least one of said plurality of frames of image data
M2 The hand held data collection terminal of claim M l , wherein said data collection terminal is adapted so that said data collection terminal subjects to an indicia decode attempt more than one of said plurality of frames of image data
N l A focus apparatus comprising a deformable lens element having an axis, wherein a major body of said deformable lens element comprises a resiliency deformable member having at least one normally convex lens surface, and an actuator for deforming said deformable lens element, the actuator having a flexible member adapted to substantially conform to a shape of said convex lens surface and having one of a coated area or an aperture disposed about said axis, the focus apparatus being adapted so that by varying a voltage applied to said flexible member a convexity of said normally convex lens surface changes
N2 The focus apparatus of claim N l , wherein said resiliency deformable member has a hardness of less then about Shore A 60 N3 The focus apparatus of claim N l , wherein said resiliency deformable member has a hardness of less than about Shore A 20
N4 The focus apparatus of claim N l , wherein said resiliency deformable member comprises silicon gel
N5 The focus apparatus of claim N l , wherein said deformable lens element is a one piece element consisting of said resiliently deformable member
N6 The focus apparatus of claim N l , wherein said flexible member is a flexible member interposed between a pair of flexible electrodes
01 A focus apparatus comprising a deformable lens element having an axis, wherein a major body of said deformable lens element comprises a resiliently deformable member having at least one convex lens surface, and an actuator for imparting a force to said deformable lens element to deform said deformable lens element and to change an optical property of said deformable lens element
02 The focus apparatus of claim Ol , wherein said actuator has an aperture disposed about said axis, said actuator being selected from the group consisting of an ion conductive electro-active polymer actuator, a dielectric electro-active polymer actuator, and a hollow stepper motor
03 The focus apparatus of claim Ol , wherein said deformable lens element has a deformable surface, at least part of which transmits image forming light rays, and where said focus apparatus includes a force imparting structural element imparting a force generated by said actuator to said deformable surface
04 The focus apparatus of claim O3, wherein said force imparting structural element is said actuator
P l A focus apparatus for use in an optical imaging system, said focus apparatus comprising, a deformable lens element having a deformable light entry surface and an opposing deformable light exit surface, the deformable lens element having an axis intersecting respective centers of said deformable light entry surface and said opposing deformable light exit surface, a first actuator for deforming said deformable light entry surface to change an optical property of said deformable lens element, and a second actuator for deforming said deformable light exit surface to change an optical property of said deformable lens element
P2 The focus apparatus of claim Pl , wherein at least one of said first and second actuators is an electro- active polymer actuator
P3 The focus apparatus of claim P l , wherein at least one of said first and second actuators has an aperture disposed about said axis P4 The focus apparatus of claim Pl , wherein said focus apparatus is adapted so that a force generated by at least one of said first and second actuators is transferred to said deformable lens element by a push ring
P5 The focus apparatus of claim P l , wherein said deformable lens element consists of a one piece resiliently deformable member
P6 The focus apparatus of claim Pl , wherein said deformable lens element has a cavity and focus fluid disposed in said cavity
P7 The focus apparatus of said claim P l , wherein said focus apparatus includes a first deformable membrane defining said light entry surface and second deformable membrane defining said second light entry surface, a window, first cavity delimited by said first deformable membrane and said window, a second cavity delimited by said second deformable membrane and said window, and focus fluid disposed in each of said first and second cavities
P8 The focus apparatus of claim P l , wherein said focus apparatus is adapted so that a force generated by at least one of said first and second actuators is imparted to said deformable lens element at a plurality of points spaced apart from and peripherally disposed about said axis
Q l A deformable lens element comprising a first clamping element, the first clamping element including a rigid transparent member having an optical surface for allowing light rays to pass there through, a deformable membrane, a second clamping member clamping said deformable membrane against said first clamping element so that said deformable membrane opposes said rigid transparent optical surface, a cavity delimited by said deformable membrane and said first clamping element, and a deformable substance having an index of refraction greater than one disposed in said cavity
Q2 The deformable lens element of claim Q l , wherein said deformable substance is provided by a resiliently deformable member
Q3 The deformable lens element of claim Q l , wherein said deformable substance comprises a focus fluid
Q4 The deformable lens element of claim Q l , wherein said optical surface is a curved surface having an optical power
Q5 The deformable lens element of claim Q l , wherein said optical surface is a planar optical surface
Q6 The deformable lens element of claim Q l , wherein said second clamping element is ultrasonically welded to said second clamping element
Q7 The deformable lens element of claim Q l , wherein at least one of said clamping elements has an annular tooth ring for increasing a securing force between said first and second clamping elements Rl A focus module comprising a boundary element, a focus element, said focus element further comprising (i) a fluid, and
(n) a deformable membrane, said fluid being entrapped between said boundary element and said deformable membrane, and a pressure element, wherein said pressure element is capable of deforming said focus element by pressing on said deformable membrane in the direction of said boundary element
S l A focus module comprising a boundary element, a focus membrane, a focus fluid entrapped between said boundary element and said focus membrane, and a deforming element contacting said focus membrane
T l A focus module comprising a boundary element, a spacer element, a focus membrane, a focus fluid entrapped between said boundary element and said focus membrane, and a deforming element contacting said focus membrane
U 1 A focus module, comprising a cylinder having (i) a top surface, (11) a bottom surface, (in) an outer wall, and (iv) a fluid interior volume therewithin, and a deforming element external to said cylinder, said deforming element being capable of exerting pressure on said top surface, thereby deforming said top surface
V l A focus module, comprising, in order a boundary element, a focus element, and a deforming element
V2 The focus module of claim V l , wherein said deforming element is in direct contact with said focus element V3 The focus module of claim V l , wherein said deforming element acts on said focus element through at least one intermediary element
V4 The focus module of claim V3, wherein said at least one intermediary element comprises a pressure element
V5 The focus module of claim V4, wherein said deforming element presses on said pressure element and said pressure element is in contact with said focus element, thereby transmitting force to said focus element
W l A lens module comprising a lens element, said lens element comprising i a working fluid component comprising a substantially optically clear fluid, and it an optical non-fluid component, comprising an elastically deformable member having first and second surfaces and being substantially optically clear over at least a portion thereof, only one of said surfaces facing towards said working fluid component, and in an optical axis passing through said working fluid component and said optical non-fluid component, a force element capable of providing an applied force sufficient to deform said elastically deformable member, and operably connected to said elastically deformable member such that force provided by said force element will be at least partially transmitted to said elastically deformable member, wherein the force provided by said force element passes in order from said force element, to the surface of said elastically deformable member facing away from said working fluid component, to said working fluid component
X l A lens module comprising a lens element, said lens element comprising i working fluid component comprising a substantially optically clear fluid, Ii an optical non-fluid component, comprising an elastically deformable member and being substantially optically clear over at least a portion thereof, and in an optical axis passing through said working fluid component and said optical non-fluid component, a force element capable of providing an applied force sufficient to deform said elastically deformable member, and operably connected to said elastically deformable member such that force provided by said force element will be at least partially transmitted to said elastically deformable member, said force element being disposed in a circumferentially symmetric relationship to said elastically deformable member Yl A focus module for use in a data collection device capable of at least one of reading 1 D bar codes, reading 2D bar codes, and taking images, said focus module comprising a boundary element, a focus element deformable in at least one dimension, a spacer element interposed between said boundary element and said focus element, an actuator element for transmitting force to said focus element, a pressure element for transmitting force from said actuator element to said focus element, a conductor element for conducting an electrical signal to said actuator element, and a power source for providing an actuating signal to said actuator element
[00451] While the present invention has been described with reference to a number of specific embodiments, it will be understood that the true spirit and scope of the invention should be determined only with respect to claims that can be supported by the present specification Further, while in numerous cases herein wherein systems and apparatuses and methods are described as having a certain number of elements it will be understood that such systems, apparatuses and methods can be practiced with fewer than the mentioned certain number of elements

Claims

We Claim
1 An apparatus for use in a lens assembly, said apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting at least one of a pushing force or a pulling force to said deformable surface
2 The apparatus of claim 1 , wherein said force imparting structural member is adapted to impart a force to said deformable surface at a plurality of force impartation points formed in a ring pattern spaced apart from and peripherally disposed about said axis
3 The apparatus of claim 1 , wherein said force imparting structural member is adapted to impart a force to said deformable surface at a plurality of force impartation points formed in an area pattern about said axis
4 The apparatus of claim 1 , wherein said force imparting structural member is an actuator
5 The apparatus of claim 1 , wherein said force imparting structural member is a structural member that transmits force generated by an actuator
6 The apparatus of claim 1 , wherein said force imparting structural member imparts a force generally in a direction of said axis
7 The apparatus of claim 1 , wherein said deformable surface partially defines a cavity that holds focus fluid
8 The apparatus of claim 1 , wherein a major body of said deformable lens element comprises a resiliency deformable material member, and wherein said deformable lens element is devoid of a focus fluid
9 The apparatus of claim 1 , wherein said apparatus is adapted so that said structural member is capable of imparting both of said pushing force and said pulling force to said deformable surface
10 The apparatus of claim 1 , wherein said apparatus is adapted so that said structural member is capable of imparting a pulling force to said deformable surface
1 1 An apparatus for use in a lens assembly, said apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting a pushing force to said deformable surface resulting in a thickness of said deformable lens member along a plurality of imaginary lines running in parallel with said imaging axis decreasing
12 The apparatus of claim 1 1 , wherein said apparatus is adapted so that when said pushing force is imparted to said deformable surface, said deformable surface bulges outward in an area of said deformable surface about said axis
13 The apparatus of claim 1 1 , wherein said apparatus is adapted so that said plurality of imaginary lines along which said thickness of said deformable lens element decreases do not include a plurality of imaginary lines running parallel with said imaging axis and intersecting said deformable surface within an area delimited by a ring shaped pattern spaced apart from and peripherally disposed about said axis
14 The apparatus of claim 1 1 , wherein said plurality of imaginary lines include imaginary lines disposed about said axis
15 An apparatus for use in a lens assembly, said apparatus comprising a deformable lens element having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting one or more of the following to said deformable surface
(a) a pushing force resulting in the deformable surface bulging outward in an area of said deformable surface about said axis, and
(b) a pulling force resulting in a shape of said deformable surface changing
16 The apparatus of claim 15, wherein said deformable surface is capable of a concave configuration and wherein said pulling force increases a concavity of said deformable surface
17 The apparatus of claim 15, wherein said deformable surface is capable of a convex configuration and wherein said pushing force increases a convexity of said deformable surface
18 The apparatus of claim 15, wherein said apparatus is adapted so that said force imparting member is capable of imparting each of said pushing force and said pulling force on said deformable surface
19 The apparatus of claim 15, wherein at least one of said pushing force and said pulling force are generated by an electro-active polymer actuator
20 The apparatus of claim 15, wherein at least one of said pushing force and said pulling force is imparted in a direction generally in a direction of said axis
21 The apparatus of claim 15, wherein a major body of said deformable lens member comprises a resiliently deformable material member
22 The apparatus of claim 15, wherein said deformable surface partially defines a cavity filled with focus fluid
23 The apparatus of claim 15, wherein said pushing force results in a thickness of said deformable lens member decreasing along an imaginary line running in parallel with and being spaced apart from said axis
24 The apparatus of claim 15, wherein said pushing force results in a thickness of said deformable lens member decreasing along a plurality of imaginary lines running in parallel with and being spaced apart from said axis, the plurality of imaginary lines being peripherally disposed about said axis
25 An apparatus for use in a lens assembly, said apparatus comprising a deformable lens member having an axis and a deformable surface, at least part of which transmits image forming light rays, and a force imparting structural member disposed to impart a force to said deformable surface, wherein said apparatus is adapted so that said force imparting structural member is capable of imparting a pushing force to said deformable surface resulting in a thickness of said deformable lens member along said axis decreasing
26 The apparatus of claim 25, wherein said force imparting member is configured to impart said pushing force to said deformable surface at a plurality of force impartation points that include an area about said axis, the force imparting member being optically clear for transmittal of image forming light rays
27 The apparatus of claim 25, wherein said deformable lens member is normally convex in an unstressed state thereof
28 The apparatus of claim 25, wherein said force imparting structural member imparts a force to said deformable surface at a plurality of points defined substantially over an entire area of said deformable surface
29 The apparatus of claim 25, wherein a major body of said deformable lens member is provided by a resiliently deformable material member
30 The apparatus of claim 25, wherein said force is generated by an electro-active polymer actuator having an optically clear area disposed about said axis
31 The apparatus of claim 25, wherein said force is generated by an electro-active polymer actuator comprising a flexible member substantially conforming to a shape of the deformable surface, the flexible member having an optically clear area disposed about said axis 32 The apparatus of claim 25, wherein said apparatus is adapted so that said pushing force is imparted in a direction generally in a direction of said axis
33 A method comprising incorporating a deformable lens element into an optical system, said deformable lens element having a deformable surface, at least part of which transmits image forming light rays, and imparting a force to said deformable surface of said deformable lens element at a plurality of force impartation points of said surface to vary an optical characteristic of said optical system, wherein said imparting step includes the step of utilizing a force imparting structural member for imparting said force
34 The method of claim 33, wherein said imparting step includes the step of utilizing an electro-active polymer actuator
35 The method of claim 33, wherein said deformable lens element has an axis, and wherein said imparting step includes the step imparting said force generally in the direction of said axis
36 The method of claim 33, wherein said plurality of force imparting points are defined in a ring pattern on said surface peripherally disposed about and spaced apart from said axis
37 The method of claim 33, wherein said plurality of force imparting points define a two dimensional area about said axis
38 The method of claim 33, wherein said force is a push force directed toward said deformable lens element
39 The method of claim 33, wherein said force is a pull force directed away from said deformable lens element
40 A method comprising incorporating a deformable lens element having an axis into an optical system, said deformable lens element having a deformable lens surface at least a part of which transmits image forming light rays, and imparting a pulling force to said deformable surface of said deformable lens element to vary an optical characteristic of said optical system, wherein said imparting step includes the step of imparting said pulling force generally in a direction of said axis
41 The method of claim 40, wherein said imparting step includes the step of utilizing an electro-active polymer actuator
42 The method of claim 40, wherein said imparting step includes the step of imparting said pulling force at a plurality of points spaced apart from and peripherally disposed about said axis
43 The method of claim 40, wherein said imparting step includes the step of utilizing a structural member 44 An optical imaging system comprising a deformable lens element having a deformable surface at least part of which transmits image forming light rays, a force imparting structural member opposing said surface, and wherein said imaging system is adapted so that a force can be imparted by said force imparting structural member at a plurality of force impartation points of said deformable surface of said deformable lens element for varying an optical characteristic of said imaging system
45 The optical imaging system of claim 44, wherein said force impartation points are defined in an area pattern about an axis of said deformable lens element
46 The optical imaging system of claim 44, wherein said force impartation points are defined in a ring pattern defined at positions spaced apart from and peripherally disposed about said axis
47 An optical imaging system comprising a deformable lens element comprising a deformable membrane, a cavity delimited by said deformable membrane, and fluid disposed in said cavity, said fluid having an index of refraction greater than one, said deformable lens element having an axis, and a force imparting structural member capable of contact with said deformable lens element at positions defined circumferentially about said axis, wherein said optical imaging system is configured so that said force imparting structural member can be moved generally in a direction of said axis either toward or away from said deformable lens element so that an optical characteristic of said imaging system vanes with movement of said force imparting structural member
48 The optical imaging system of claim 47, wherein said force imparting structural member is provided by a ring-shaped pressure element
49 The optical imaging system of claim 47, wherein said force imparting structural member is provided by a plurality of tab-like elements of an electro-active polymer actuator
50 The optical imaging system of claim 47, wherein said force imparting structural member is provided by a flexible member of an electro-active polymer
51 An optical imaging system comprising a deformable lens element comprising a deformable membrane, a cavity delimited by said deformable membrane, and fluid disposed in said cavity, said fluid having an index of refraction greater than one, said deformable lens element having an axis, a ring-shaped pressure element in contact with said deformable lens element and arranged circumferentially about said axis, and an electro-active polymer actuator mechanically coupled to said ring-shaped pressure element, said optical imaging system being configured so that said electro-active polymer actuator moves said ring-shaped pressure element generally in a direction of said axis so that an optical characteristic of said imaging system vanes with movement of said ring-shaped pressure element
52 The optical imaging system of claim 51 , wherein said electro-active polymer actuator includes a ring- shaped deformable element comprising a plurality of tab-like elements, said deformable element being circumferentially disposed about said axis, said plurality of tab-like elements engaging said ring shaped pressure element
53 An optical imaging system comprising a deformable lens element having an axis, wherein a major body of said deformable lens element is provided by a resiliently deformable member having a hardness measurement of less than Shore A 60, and wherein said imaging system is configured so that a force can be applied to an external surface of said deformable lens for varying an optical characteristic of said imaging system
54 The optical imaging system of claim 53, wherein said optical imaging system includes a flexible member actuator for imparting said force, said actuator having a flexible member adapted to substantially conform to a shape of said deformable lens element
55 An optical system for use in imaging an object, said system comprising a deformable lens element capable of being deformed wherein said deformable lens element has a deformable surface that faces an exterior of said deformable lens element, said deformable lens element having an axis, wherein said optical system is adapted so that said system can impart a force to said deformable surface generally in a direction of said axis toward said deformable lens element in such manner that an optical property of said deformable lens element is changed by impartation of said force
56 The optical system of claim 55, wherein said optical system is adapted so that said system imparts said force at a plurality of positions spaced apart from and peripherally disposed about said imaging axis
57 The optical system of claim 55, wherein said optical system includes an actuator including an aperture disposed about said axis for imparting said force to said deformable lens element generally in a direction of said axis
58 An optical system for use in imaging an object, said system comprising a deformable lens element having a deformable lens surface, at least part of which transmits image forming light rays and which faces an exterior of said deformable lens element, said deformable lens surface being one of normally convex or capable of exhibiting a convex curvature, said deformable lens element having an axis, and an actuator for imparting a force to said deformable surface, the actuator having an aperture disposed about said axis, the optical system being adapted so that actuation of said actuator results in a force being imparted to said deformable surface to vary a convexity of said deformable lens element
59 The optical system of claim 58, wherein said optical system includes a pressure element transferring a force generated by said actuator to said deformable lens element
60 The optical system of claim 58 wherein said deformable lens element is configured so that, for achieving deformation thereof, said deformable lens element is contacted at a plurality of positions spaced apart from and peripherally disposed about said axis
61 The optical system of claim 58, wherein said optical system includes a force imparting structural member for imparting a force generated by said actuator and for imparting said force generated by said actuator to said deformable surface
62 The focus apparatus of claim 61 , wherein said force imparting structural element is said actuator
63 A hand held data collection terminal comprising a two dimensional image sensor comprising a plurality of pixels formed in a plurality of rows and columns of pixels, an imaging lens assembly comprising a deformable lens element for focusing an image onto said two dimensional image sensor, said imaging lens being adapted so that said deformable lens element can be deformed with use of a force imparting structural member, said imaging lens assembly being adapted so that force can be applied to an external surface of said deformable lens element to vary an optical property of said deformable lens element, said imaging lens setting having a first lens setting at which said deformable lens element is in a first state and a second lens setting at which said deformable lens element is in a second state, and a trigger for activating a trigger signal, said data collection terminal being adapted so that said trigger signal can be maintained in an active state by maintaining said trigger in a depressed position, wherein said data collection terminal is adapted so that responsively to said trigger signal being maintained in said active state, said data collection terminal captures in succession a plurality of frames of image data, each of said plurality of frames of image data representing light incident on said image sensor at an instant in time, wherein said data collection terminal is adapted so that a lens setting of said imaging lens assembly is varied while said trigger signal is maintained in said active state in such manner that said lens assembly is at said first setting for an exposure period corresponding to at least one of said plurality of frames of image data, and said lens assembly is at said second lens setting for an exposure period corresponding to at least one of said plurality of frames of image data
64 The hand held data collection terminal of claim 63, wherein said data collection terminal is adapted so that said data collection terminal subjects to an indicia decode attempt more than one of said plurality of frames of image data
65 A focus apparatus comprising a deformable lens element having an axis, wherein a major body of said deformable lens element comprises a resiliently deformable member having at least one normally convex lens surface, and an actuator for deforming said deformable lens element, the actuator having a flexible member adapted to substantially conform to a shape of said convex lens surface and having one of a coated area or an aperture disposed about said axis, the focus apparatus being adapted so that by varying a voltage applied to said flexible member a convexity of said normally convex lens surface changes
66 The focus apparatus of claim 65, wherein said resiliently deformable member has a hardness of less then about Shore A 60
67 The focus apparatus of claim 65, wherein said resiliently deformable member has a hardness of less than about Shore A 20
68 The focus apparatus of claim 65, wherein said resiliently deformable member comprises silicon gel
69 The focus apparatus of claim 65, wherein said deformable lens element is a one piece element consisting of said resiliently deformable member
70 The focus apparatus of claim 65, wherein said flexible member is a flexible member interposed between a pair of flexible electrodes
71 A focus apparatus comprising a deformable lens element having an axis, wherein a major body of said deformable lens element comprises a resiliently deformable member having at least one convex lens surface, and an actuator for imparting a force to said deformable lens element to deform said deformable lens element and to change an optical property of said deformable lens element
72 The focus apparatus of claim 71 , wherein said actuator has an aperture disposed about said axis, said actuator being selected from the group consisting of an ion conductive electro-active polymer actuator, a dielectric electro-active polymer actuator, and a hollow stepper motor
73 The focus apparatus of claim 71 , wherein said deformable lens element has a deformable surface, at least part of which transmits image forming light rays, and where said focus apparatus includes a force imparting structural element imparting a force generated by said actuator to said deformable surface
74 The focus apparatus of claim 73, wherein said force imparting structural element is said actuator 75 A focus apparatus for use in an optical imaging system, said focus apparatus comprising, a deformable lens element having a deformable light entry surface and an opposing deformable light exit surface, the deformable lens element having an axis intersecting respective centers of said deformable light entry surface and said opposing deformable light exit surface, a first actuator for deforming said deformable light entry surface to change an optical property of said deformable lens element, and a second actuator for deforming said deformable light exit surface to change an optical property of said deformable lens element
76 The focus apparatus of claim 75, wherein at least one of said first and second actuators is an electro- active polymer actuator
77 The focus apparatus of claim 75, wherein at least one of said first and second actuators has an aperture disposed about said axis
78 The focus apparatus of claim 75, wherein said focus apparatus is adapted so that a force generated by at least one of said first and second actuators is transferred to said deformable lens element by a push ring
79 The focus apparatus of claim 75, wherein said deformable lens element consists of a one piece resiliently deformable member
80 The focus apparatus of claim 75, wherein said deformable lens element has a cavity and focus fluid disposed in said cavity
81 The focus apparatus of said claim 75, wherein said focus apparatus includes a first deformable membrane defining said light entry surface and second deformable membrane defining said second light entry surface, a window, first cavity delimited by said first deformable membrane and said window, a second cavity delimited by said second deformable membrane and said window, and focus fluid disposed in each of said first and second cavities
82 The focus apparatus of claim 75, wherein said focus apparatus is adapted so that a force generated by at least one of said first and second actuators is imparted to said deformable lens element at a plurality of points spaced apart from and peripherally disposed about said axis
83 A deformable lens element comprising a first clamping element, the first clamping element including a rigid transparent member having an optical surface for allowing light rays to pass there through, a deformable membrane, a second clamping member clamping said deformable membrane against said first clamping element so that said deformable membrane opposes said rigid transparent optical surface, a cavity delimited by said deformable membrane and said first clamping element, and a deformable substance having an index of refraction greater than one disposed in said cavity
84 The deformable lens element of claim 83, wherein said deformable substance is provided by a resiliency deformable member
85 The deformable lens element of claim 83, wherein said deformable substance comprises a focus fluid
86 The deformable lens element of claim 83, wherein said optical surface is a curved surface having an optical power
87 The deformable lens element of claim 83, wherein said optical surface is a planar optical surface
88 The deformable lens element of claim 83, wherein said second clamping element is ultrasonically welded to said second clamping element
89 The deformable lens element of claim 83, wherein at least one of said clamping elements has an annular tooth ring for increasing a securing force between said first and second clamping elements
90 A focus module comprising a boundary element, a focus element, said focus element further comprising
(n) a fluid, and
(n) a deformable membrane, said fluid being entrapped between said boundary element and said deformable membrane, and a pressure element, wherein said pressure element is capable of deforming said focus element by pressing on said deformable membrane in the direction of said boundary element
91 A focus module comprising a boundary element, a focus membrane, a focus fluid entrapped between said boundary element and said focus membrane, and a deforming element contacting said focus membrane
92 A focus module comprising a boundary element, a spacer element, a focus membrane, a focus fluid entrapped between said boundary element and said focus membrane, and a deforming element contacting said focus membrane
93 A focus module, comprising a cylinder having
(i) a top surface, (ii) a bottom surface, (in) an outer wall, and (iv) a fluid interior volume therewithin, and a deforming element external to said cylinder, said deforming element being capable of exerting pressure on said top surface, thereby deforming said top surface
94 A focus module, comprising, in order a boundary element, a focus element, and a deforming element
95 The focus module of claim 94, wherein said deforming element is in direct contact with said focus element
96 The focus module of claim 94, wherein said deforming element acts on said focus element through at least one intermediary element
97 The focus module of claim 96, wherein said at least one intermediary element comprises a pressure element
98 The focus module of claim 97, wherein said deforming element presses on said pressure element and said pressure element is in contact with said focus element, thereby transmitting force to said focus element
99 A lens module comprising a lens element, said lens element comprising i a working fluid component comprising a substantially optically clear fluid, and ii an optical non-fluid component, comprising an elastically deformable member having first and second surfaces and being substantially optically clear over at least a portion thereof, only one of said surfaces facing towards said working fluid component, and in an optical axis passing through said working fluid component and said optical non- fluid component, a force element capable of providing an applied force sufficient to deform said elastically deformable member, and operably connected to said elastically deformable member such that force provided by said force
P element will be at least partially transmitted to said elastically deformable member, wherein the force provided by said force element passes in order from said force element, to the surface of said elastically deformable member facing away from said working fluid component, to said working fluid component
100 A lens module comprising a lens element, said lens element comprising ii working fluid component comprising a substantially optically clear fluid, ii an optical non-fluid component, comprising an elastically deformable member and being substantially optically clear over at least a portion thereof, and in an optical axis passing through said working fluid component and said optical non-fluid component, a force element capable of providing an applied force sufficient to deform said elastically deformable member, and operably connected to said elastically deformable member such that force provided by said force element will be at least partially transmitted to said elastically deformable member, said force element being disposed in a circumferentially symmetric relationship to said elastically deformable member
101 A focus module for use in a data collection device capable of at least one of reading 1 D bar codes, reading 2D bar codes, and taking images, said focus module comprising a boundary element, a focus element deformable in at least one dimension, a spacer element interposed between said boundary element and said focus element, an actuator element for transmitting force to said focus element, a pressure element for transmitting force from said actuator element to said focus element, a conductor element for conducting an electrical signal to said actuator element, and a power source for providing an actuating signal to said actuator element
PCT/US2007/025707 2006-12-15 2007-12-14 Apparatus and method comprising deformable lens element WO2008076399A2 (en)

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US60/961,036 2007-07-18
US11/781,901 2007-07-23
US11/781,901 US8027096B2 (en) 2006-12-15 2007-07-23 Focus module and components with actuator polymer control
US11/897,924 US7813047B2 (en) 2006-12-15 2007-08-31 Apparatus and method comprising deformable lens element
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WO2008076399A3 (en) 2008-09-25
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