DE102008027518B3 - Mirror lens e.g. observation lens for use in e.g. spatial spectrometer in field monitoring, has four mirrors, where first and fourth mirrors are deformed to allow position of image plane of lens to remain unchanged in range of focus depth - Google Patents

Abstract

The lens (100) has four mirrors (110-140), where the first and fourth mirrors (110, 140) are formed as deformable mirrors. The mirrors are arranged so that a bend optical path (102) extends from the first mirror (110) to the fourth mirror (140). The first and fourth mirrors (110, 140) are deformed so that an image angle of the lens is changed by deformation of a mirror surface of the first mirror (110) with deformation of a mirror surface of the fourth mirror (140) to allow a position of an image plane (160) of the lens to remain unchanged in a range of a focus depth. Independent claims are also included for the following: (1) a spatial spectrometer having a mirror lens (2) an image recording system having a mirror lens (3) a method of operating a central shadowing effect free mirror lens.

Description

embodiments according to the invention refer to a central shading-free mirror objective with a variable angle of view comprising at least four mirrors, of which two mirrors are designed as deformable mirrors.

Some embodiments according to the invention refer to a mirror zoom lens. The term "zooming" means doing a changeable Adjusting the image angle and thus also the system focal length.

The possibility the angle of view and thus the magnification of an optical image to be able to adjust has led to widespread use of such systems. In the technical and not technical photography about Automation technology and image processing up to field monitoring and Remote Sensing use lenses of this type.

The different applications are in a wide spectral range encountered. It extends from the ultraviolet (UV) over the Visible (VIS) to the infrared range (IR). While normal Photography and automation often use the VIS are field monitoring and remote sensing often also common in the IR.

The Adjust the angle of view and thus also the system focal length (the so-called "zooming") can in principle by moving optical function elements in the lens or by changing their properties, such. As the refractive power of a lens achieved become.

Of the Image angle or lens angle indicates the area of space from which Radiation along a beam path through the lens on a Image plane drops. A small system focal length has a large field of view and a large system focal length a small angle.

mirror lenses with fixed focal lengths, so fixed angle of view, have long been known and find especially as langbrennweitige versions as picture-taking and observation lenses in photography and Astronomy application.

optical Systems whose functional elements are based only on reflection have the advantage of producing no chromatic aberrations and thus for one broad spectral range (UV over VIS to IR) to be applicable. By eliminating chromatic aberration becomes common here a higher one image quality achieved in comparison to refractive systems. They also own across from the latter have the advantage of a lower mass and often also cheaper Production.

Basically, lenses can after their construction, for example as on-axis systems or axial systems, Off-axis systems or extra-axial Systems or Schiefspiegler can be distinguished.

at a centered sequence of surfaces of revolution can their centers of curvature lie on a straight line which is the optical axis of the surface sequence represents. Such systems are also called on-axis systems or axial Called systems.

Mirror systems, whose functional elements have a common optical axis, however, at least partially asymmetric and thus extraaxial Patches of the Functional elements are also used off-axis systems or extra-axial Called systems.

lenses in which at least two of the optical functional elements no common have optical axis, are referred to as Schiefspiegler.

The above-mentioned mirror lenses, in particular for astronomical applications, are usually rotationally symmetrical with respect to a common axis of symmetry, which, such. B. in "Heinz Haferkorn, Optics - Physical and technical fundamentals and applications, 3rd, edited and expanded edition, Leipzig; Berlin; Heidelberg; Barth, 1994 ", referred to as optical axis (" on-axis systems ", axial systems). This results in a central shading of the beam path, which has a constrast-reducing and thus a negative effect on the image quality. A centered mirror lens with Zentralabschattung is for example in the DE 2916192 C2 shown.

Under Zentralabschattungsfrei one understands that the elements of a lens are arranged so that a centrally incident beam of rays along the beam path unhindered reaches the image plane.

Rather, mirror systems whose functional elements have a common optical axis, but at least partially asymmetric and thus use off-axis patches of the functional elements ("off-axis systems", off-axis systems, for example, shown in the DE 2916192 C2 , in the US 4598981 , in "Giampiero Naletto, Vania Da Deppo, Maria Guglielmina Pelizzo, Roberto Ragazzoni and Enrico Marchetti, Optical design of the Wide Angle Camera for the Rosetta mission, Applied Optics Vol. 41, No. 7, March 1, 2002", in " Dietrich Korsch, Design and Optimization Technique for three-mirror telescopes, Applied Optics Vol. 19, No. 21, November 1, 1980 ", in" Dietrich Korsch, Reflective Optics, ISBN 0124211704, Academic Press, London 1991 "). They therefore consist of a series of centered surfaces of revolution whose centers of curvature lie on a straight line, but the mechanical center of the optical elements does not coincide with the optical axis.

Another class of mirror optics are the so-called Schiefspiegler, such as the DE 4314499 A1 . DE 4426224 A1 and DE 19925931 C2 demonstrate. These are systems that have no common optical axis, since the centers of curvature of the mirror surfaces are not on a straight line.

Around in such systems the inherent large geometric aberrations, In particular, the astigmatism to be able to correct have Schiefspiegler often only small openings or aperture numbers or initial openings (defined as the quotient of the system focal length and the diameter of the Entrance pupil) of about 8 to 20 and are therefore faint. The correction of aberrations in these oblique mirror systems often requires additional Activities. In particular, a construction known as Yolo-Schiefspiegler uses in addition to Correction of axial astigmatism a toric secondary mirror, as in "Herwin G. Ziegler, The Yolo System, URL: http://www.astronomie.info/sag/yolo, Access: 1/2008 "shown.

An off-axis system with a large angle of view and a f-number of 4 is for example in the US 5144476 A to find. Giampiero Naletto, Vania Da Deppo, Maria Guglielmina Pelizzo, Roberto Ragazzoni and Enrico Marchetti, Optical design of the Wide Angle Camera for the Rosetta mission, Applied Optics Vol. 41, No. 7, March 1, 2002 "is another Off Axis system with a comparable angle of view and an initial opening 3.2 shown.

In addition to fixed focal length systems, some variable focal length systems (zoom systems) are also known. These include, for example, long focal length mirror zoom objective in which the zoom effect is achieved by a shift of individual mirror or mirror groups, such. B. in the US 5144476 A Wang Chang, Zongtian Wang, Tingcheng Yhang, MM Talha, All-optical zoom Systems for infrared optics, International Optical Design Conference 2006, SPIE-OSA Bd. 6,342, Allen Mann and R. Barry Johnson, Design and Analysis of a compact, wide field, unobscured zoom mirror system, SPIE Vol. 3.129 ", in" R. Barry Johnson and Allen Man, Evolution of a compact, wide field-of-view, unobscured, all-reflective zoom optical system, SPIE Vol. 3.061 ", in" R. Barry Johnson, Unobscured reflective zoom Systems, SPIE Vol. 2.539 ", in" R. Barry Johnson, James B. Hadaway and Tom Burleson, All-Reflective Four-Element Zoom Telescope: Design and Analysis, SPIE Vol. 1.354 ", in" Thomas H. Jamieson, Zoom Optics with Off-set Cassegrain and Reflective Relay, SPIE Bd 2.539 ". These systems have the great disadvantage that precise guidance and mechanical displacement of the often large and heavy mirrors is very expensive. With regard to mechanical (long-term) stability and precision are optical components without macroscopic shifts, ie z. For example, those which have a selectively variable refractive power, an advantage.

Zoom lenses containing optical elements with variable refractive powers are often based on the use of so-called liquid lenses and thus do not constitute purely reflective systems. These optical functional elements consist essentially of two immiscible liquids trapped in a cavity whose interface has a refractive effect and can be specifically changed in their curvature and thus the refractive power. It is fundamentally to be distinguished between hybrid systems (mixing systems) in which liquid lenses and displaceable groups are combined, as for example in US Pat US 6464363 B1 or in Wippermann, P. Schreiber, A. Bräuer, B. Berge, Mechanically assisted liquid zoom systems for mobile phone cameras, Proc. of SPIE Vol. 6.280, 2006 "and systems without movable components such. B. in the WO 2004038480 A1 . US 2007104473 A1 . US 6464363 B1 or in "S. Kuiper, BHW Hendriks, JF Suijver, S.Deladi, I. Helwegen, Zoom camera based on liquid lenses, Proc. of SPIE Vol. 6.466, 2007 ". Liquid lenses are, however, like all refractive optical functional elements, fundamentally subject to wavelength-dependent aberrations. Moreover, they are only in spectralbe can be used rich in which they have a sufficient transmission.

Furthermore, a small number of exclusively reflection-based zoom systems using deformable mirror to change the focal length from the literature is known, as in the DE 2916192 C2 shown. Zoom lenses, after in the DE 2916192 C2 described type, have two deformable mirrors. They have the disadvantage that only for a maximum of two focal lengths of the entire zoom range can a specific aberration, the so-called field curvature, be corrected (see "FC Wippermann, P. Schreiber, A. Bräuer, P. Craen, Bifocal liquid lens zoom objective for mobile phone application, Proc. of SPIE-IS & T Electronic Imaging, SPIE Vol. 6.501, 2007 "). Since no additional mirrors are provided in order to divide the refractive powers, a strong field curvature can arise in the other focal lengths of the zoom lens, which can lead to a significant degradation of the image quality.

In the US 4059346 A and in the US 2006170766 A1 are two variants, an on-axis system and a tilted mirror system, described with two deformable mirrors. The indicated there mirror arrangements, however, have aberrations that significantly reduce the image quality. Furthermore, some of the systems described are not shading-free or use additional refractive optical elements.

More complex optical arrangements, which have at least two active optical elements, are for example in US 6977777 B1 shown. These arrangements include other optically passive elements such as lenses, mirrors or beam splitters. However, the systems are described as having a low field of view of approximately 0.05 ° for the shortest focal length for many applications. In addition, the structures described have partially intermediate image planes in the beam path between the mirrors, resulting in a larger volume of construction result than in a system without intermediate image plane. An equivalent publication to the US 6977777 B1 is, for example, "Wick, et al: Active optical zoom system, SPIE Vol. 5798.2005". There, for example, the large footprint of the structure and the considerable electronic effort is shown.

The used in the above patent active or adaptive mirror opposite Mirrors in which only the curvature can be changed, an additional functionality on. With the help of a variety of micromechanical actuators can the mirror profile can be changed specifically in higher spatial frequencies and thus a correction of the zoom state-dependent aberrations are performed. With this approach, it is basically possible, the picture quality significantly increase in a Schiefspiegelzoomsystem. The serious one The disadvantage, however, is that the adaptive mirrors required for this very complicated and therefore costly to manufacture and are a complex electronic control is required. mirror with segmented actuators usually have a deflection of a few micrometers and are very expensive to control. The fill factor the mirror lets usually not a strong folded beam path too. Thus, with these Components cost-effective Systems with a moderate volume and a wide range of focal length change not feasible.

Other examples of zoom systems based on deformable mirrors are in US 2006170766 A1 listed. However, these are mostly more complex structures containing additional lenses and beam splitters. The purely reflective systems indicated below have a low imaging quality due to the mirror arrangement.

Furthermore, for example, describe the US 6464363 B1 , the US 7025468 B2 and the US 20060187563 A1 decentered systems with elements of variable optical properties. The solutions specifically presented therein require a rotationally asymmetric free form for the deformable mirror, which is realized mathematically via polynomials up to at least grade 15. During deformation, all parameters of the polynomial change. The realization and control of such a mirror is enormously complex. The Indian US 6464363 B1 in 64 single, illustrated and described, purely reflective two-mirror approach with a deformable mirror shows strong geometrical aberrations on the image. To correct for these aberrations, other lenses and prismatic bodies are used in the other examples which cause additional chromatic aberration. The in the US 6464363 B1 zoom systems used to change the system focal length using a deformable mirror and additionally displaceable lens groups.

In addition to the multitude of systems already described, a wide variety of macroscopic approaches for deformable mirrors and their actuation are also known. In the US 683163 A for example Membrane mirror fluidic or in the US 3972600 A pneumatically curved.

In the DE 3012830 C2 a piezoelectric, variably bendable bimorph plate is described. In the DE 4236355 C2 Also described is a deformable by means of piezo actuators mirror. It consists of a thin plate clamped between two annular cutting edges, the deformation of which is brought about by actuators made of piezo stacks.

Finally finds one in "W. Greger u. a., Low-cost deformable mirror for laser focusing, Proc. of SPIE vol. 6.374, 2006 "one Description of Electromagnetically Actuatable Polymer Levels.

Further examples are in the patents EP 152268 B1 . US 5170284 A . US 2004227838 A1 . US 2007109667 A1 . US 7265911 B2 . WO 2005069054 A2 . DE 10 2005 030 001 A1 and WO 2006103290 A1 David B. Wick, Ty Marinez, Don M. Payne, William C. Sweatt and Sergio R. Restaino, Spaceborne Sensors II Active Proximity Systems, Proc. of SPIE vol. 5.798 "and in" J. Michael Rodgers, Unobscured mirror designs, International Optical Design Conference, 2002, Proc. of SPIE vol. 4.832 ".

The US 2008/0088811 A1 Fig. 10 shows an imaging or exposure apparatus which includes, inter alia, an optical projection system having a series of mirrors, at least two of which are deformable. The optical projection system has a common optical axis and the two deformable mirrors are arranged behind one another as the last two mirrors in the beam path.

The deformable mirrors have the task in this lithography system Aberrations possible good to compensate.

The further shows the US Pat. No. 6,721,510 B2 an atmospheric optical communication system comprising a plurality of transceivers. Each of these transceivers includes exactly one deformable mirror.

In addition, the shows DE 197 31 964 A1 a spectrometer with an aspherical mirror with large area and high accuracy. The spectrometer comprises a light source, a spectroscopic element and a reflecting mirror. The reflecting mirror is brought into its aspherical form by applying an external force to a given plate.

The The object of the present invention is a high-contrast zoom lens with high picture quality too create that for a big Wavelength range is designed and thereby compact and / or inexpensive to produce.

These The task is performed by a mirror shadow lens free of shading solved with a variable angle of view according to claim 1.

One embodiment according to the invention creates a central shading-free mirror lens with a variable angle of view, which is a first mirror that is considered deformable Mirror is designed, a second mirror whose mirror surface a aspherical Form, a third mirror whose mirror surface a aspherical Form, and a fourth mirror, as deformable Mirror is designed includes. It is the first to fourth mirror arranged so that at least two mirrors the first to fourth Mirror have a different optical cal axis, and that a folded beam path from the first mirror over the second mirror and over extending the third mirror to the fourth mirror. Furthermore the first to fourth mirrors are arranged and shaped so that in the beam path between the first mirror and the fourth Mirror is not an intermediate image plane. In addition, the first and the fourth mirror so deformable that by deformation of the mirror surface of the first mirror combined with a deformation of the mirror surface of the mirror fourth mirror the angle of view of the lens is changed and thereby a position of an image plane of the central shading-free Mirror lens in an area of a depth of field remains unchanged.

Embodiments according to the invention are based on the core idea of providing a central shading-free mirror objective with a variable image angle using four mirrors, two of the four mirrors being designed as deformable mirrors for changing the angle of view. The mirrors are arranged so that at least two of the four mirrors of the mirror objective have a different optical axis, which corresponds to a Schiefspiegleraufbau. As a result, the first to fourth mirror can be arranged so that the mirror lens central shading free and thus much kon richer in quality than systems with Zentralabschattung.

The Use of reflective optical elements allows it wave dependent To prevent aberrations or a chromatic aberration. The mirror objective is therefore in a wide wavelength range of the electromagnetic Spectrum applicable.

A Reduction of the construction volume can be achieved by the first to fourth mirror is arranged and shaped so that in the beam path between the first mirror and the fourth mirror no intermediate image level is located. An intermediate image plane would be the optical path between the first mirror and the fourth mirror enlarge and the mirrors would have to thus at a greater distance from each other to be ordered. The inventive arrangement of the first to fourth mirror, which has no intermediate image plane, thus can a compact mirror lens can be created.

By the use of an aspherical second mirror and an aspherical third mirror can Aberrations, such as astigmatism, over the entire focal length range or over the variation range of Corrected angle of view sufficient and thus delivered a usual image quality for camera technology become.

On Reflection-based optical systems have, compared to systems, the refractive optical functional elements, such. B. lenses, the advantage of producing no chromatic aberrations. Therefore they are usually for a much wider spectral range, different from the ultraviolet (UV) over the visible (VIS) can extend to the infrared (IR) can be used. For many Applications, especially those with multispectral and spectral broadband requirements, mirror optics are refractive systems therefore superior.

Farther mirror lenses often have less mass than lens lenses and are also cheaper to manufacture.

Of Further, mirror lenses do not require complex antireflection coatings necessary.

In Connection with few optical surfaces and a Schiefspiegler approach can disturbing Reflexes, as they often do to be completely avoided in refractive systems. In order to For example, the mirror zoom lens is suitable for taking pictures in connection with highly dynamic, logarithmic image sensors.

Of Further, with this approach, for example, the so-called Narcissus Effect eliminated. The narcissus effect mainly occurs Infrared lenses on and is dependent on the angle of the image disturbing back-reflexes causing ghosting on the detector can.

The Schiefspiegelzoomobjektiv thus combines, among others, the above Advantages of mirror optics over refractive systems with the use of deformable mirrors for the targeted adjustment of the Picture angle.

at some embodiments according to the invention the deformable mirrors have rotationally symmetric mirror surfaces. Despite the use of rotationally symmetric deformable mirror points the mirror lens in contrast to a variety of existing system approaches one extraordinarily high optical degree of correction and thus a high image quality over the entire focal length range or image angle range. The use of rotationally symmetrical deformable mirrors additionally has the Advantage that these mirrors with few actuators and get along thus have a simple structure and a simple control. This can reduce the volume of construction and reduce costs.

Some embodiments according to the invention refer to a shading-free mirror zoom lens, which with a total of four mirrors, two of them deformable, one over the entire focal length range for the camera technology usual picture quality supplies.

In some embodiments according to the invention, the use of deformable mirrors as the first mirror and as the fourth mirror enables a variable image angle and thus an adjustable system focal length. This change in the angle of view is achieved by a deformation of the mirror surface of the first mirror combined with a deformation of the mirror surface of the fourth mirror. The position of the image plane of the mirror objective remains unchanged in a region of the depth of field. The use of deformable mirrors for the purpose of setting the angle of view has the advantage that complex macroscopic precision bearings and precision positioning elements which can be constructed costly and which are set for an objective in which the image angle is adjusted by displacing part of its optical components. Therefore, the lens compared to solutions with sliding mirrors a much greater stability and robustness, for example, to vibration and external influences. In addition, superstructures with displaceable mirrors usually require a large amount of installation space, since the travel paths are often considerable. The use of deformable mirrors thus allows a significant reduction in the volume of construction, since here the movement of the mirror surfaces can be considered as almost negligible relative to the dimensions of the system determining components. For example, since no macroscopic mechanics is necessary and the volume of construction is lower, the cost of producing the lens can be reduced.

Some further embodiments according to the invention refer to a simple, compact, inexpensive to manufacture and optically high quality mirror zoom lens for image acquisition, the Zoom effect on a focal length change of a part of his based on optical components. The system has an example three times the variation range of the total focal length. It points a central shading-free beam path, for example the achievement of a high image quality allows. Different image angle ranges, z. B. equivalent to a small picture Focal length range from 35 mm to 105 mm, thereby being different variants covered by the mirror zoom lens. The mirror zoom lens has doing one for Schiefspiegler big maximum aperture for example 4.5 for that mentioned above Example or the above Zoom range. Taking advantage of an exclusively on Reflection-based structure and, for example, the resulting Freedom from wavelength-dependent aberrations The mirror zoom lens is in a wide range of electromagnetic Spectrum applicable.

In Combination with modern image sensors, such. B. CCD sensors ("CCD": "charge coupled device ", charge-coupled sensor) or CMOS sensors ("CMOS": complementary metal-oxide-semiconductor, complementary metal oxide semiconductor sensors), The mirror lens provides a camera system with variable angle of view and high picture quality over that entire zoom range.

at some embodiments according to the invention it is a system for optical imaging and image acquisition with changeable or adjustable angle of view, a so-called zoom lens, which is designed as a mirror look is.

Some embodiments according to the invention have the advantage that they are due to the execution as Mirror optics for the entire spectral range from UV to IR are suitable. Pure on reflection based systems have no wavelength dependent aberrations and achieve a high image quality. One such wavelength-dependent imaging fields (chromatic aberration) is in contrast to refraction in all based lenses (lens lenses), though more or less corrected, always available. Among other things, lens lenses in contrast to the mirror optics only within a limited spectral range used.

at some embodiments according to the invention can be avoided by the Schiefspiegelansatz a central shading whereby no contrast reducing diffraction effects caused thereby occur.

Further embodiments according to the invention use deformable mirrors to adjust the angle of view. The deformation is used to change the radius of curvature the mirror and thus bring the focal length. The zoom effect is achieved with a suitable combination of several such mirrors.

The Achieving a high image quality over a wide range of the electromagnetic spectrum is due to the Use of reflective optical functional elements allows. Accordingly, some embodiments according to the invention exclusively Mirror as optically imaging or distracting functional elements on. Furthermore possible the central shading-free design approach or construction an increase the image resolution above the entire zoom range of the lens.

In further embodiments according to the invention, a high degree of correction (aberration) of the optical system is achieved through the use of non-spherical mirror surfaces. For example, conical and biconical surfaces play a role here. So that the complexity of the system For example, the deformable mirrors can be designed as rotationally symmetrical elements.

A size mechanical stability and reliability of the system in combination with a small volume of construction can through the use of deformable mirrors instead of sliding functional elements to adjust the angle of view. The manufacturability The system and its components are becoming more common today Precision machinery ensured.

embodiments according to the invention will be explained in more detail with reference to the accompanying figures. It demonstrate:

1 a schematic representation of a central shading-free mirror lens with a variable angle of view;

2 a schematic representation of an optical arrangement of a mirror zoom lens;

3 a schematic representation of the in 2 shown mirror zoom lens with a focal length of 5.3 mm;

4 a spot diagram of the in 3 shown mirror zoom lens with a focal length of 5.3 mm;

5 a schematic representation of the in 2 shown mirror zoom lens with a focal length of 7.9 mm;

6 a spot diagram of the in 5 shown mirror zoom lens with a focal length of 7.9 mm;

7 a schematic representation of the in 2 shown mirror zoom lens with a focal length of 15.8 mm;

8th a spot diagram of the in 7 shown mirror zoom lens with a focal length of 15.8 mm;

9 a schematic representation of an optical arrangement of a telephoto zoom lens;

10 a schematic representation of the in 9 telephoto zoom lens with a focal length of 10.5 mm;

11 a spot diagram of the in 10 telephoto zoom lens with a focal length of 10.5 mm;

12 a schematic representation of the in 9 shown telephoto zoom lens with a focal length of 15.8 mm;

13 a spot diagram of the in 12 shown telephoto zoom lens with a focal length of 15.8 mm;

14 a schematic representation of the in 9 shown telephoto zoom lens with a focal length of 31.5 mm;

15 a spot diagram of the in 14 shown telephoto zoom lens with a focal length of 31.5 mm;

16 a schematic representation of an optical arrangement of a super telephoto mirror zoom lens;

17 a schematic representation of the in 16 shown super telephoto mirror zoom lens with a focal length of 30 mm;

18 a spot diagram of the in 17 shown super telephoto mirror zoom lens with a focal length of 30 mm;

19 a schematic representation of the in 16 shown super-telephoto zoom lens with a focal length of 60 mm;

20 a spot diagram of the in 19 shown super-telephoto zoom lens with a focal length of 60 mm;

21 a schematic representation of the in 16 shown super-telephoto mirror zoom lens with a focal length of 90 mm;

22 a spot diagram of the in 21 shown super-telephoto mirror zoom lens with a focal length of 90 mm;

23 a schematic representation of an image pickup system with a mirror zoom lens and two image sensors;

24 a schematic representation of an image pickup system with a mirror zoom lens with combined cover glass;

25 a schematic representation of an image pickup system with a mirror zoom lens and an additional Offner-Relay arrangement;

26a . 26b a schematic representation of an optical functional element for defining a reference point and a direction vector for an optically active surface;

27 a schematic representation of an optical arrangement for defining reference quantities; and

28 a schematic representation of an optical arrangement with reference variables.

1 shows a schematic representation of a central shading-free mirror objective 100 variable angle picture according to an embodiment of the invention. The mirror lens 100 includes a first mirror 110 which is designed as a deformable mirror, a second mirror 120 whose mirror surface has an aspherical shape, a third mirror 130 whose mirror surface has an aspherical shape and a fourth mirror 140 which is designed as a deformable mirror. In this case, the first to fourth mirrors are arranged so that at least two mirrors of the first to fourth mirrors have a different optical axis. In other words, a maximum of three of the four optical axes 112 . 122 . 132 . 142 or the four mechanical center axes of the first to fourth mirror lie on a straight line and thereby form a common optical axis. Therefore, it is a Schiefspiegleraufbau, which, for example, a central shading free arrangement of the first to fourth mirror is made possible.

Furthermore, the first to fourth mirror is arranged so that a folded beam path 102 from the first mirror 110 over the second mirror 120 and about the third mirror 130 to the fourth mirror 140 extends. The arrangement of the first to fourth mirror is additionally designed so that in the beam path 102 between the first mirror 110 and the fourth mirror 140 no intermediate image plane is located. As a result, the mirror objective can be made more compact than in the case of lenses with an intermediate image plane, since an intermediate image plane forms the beam path 102 would extend.

Furthermore, the first mirror 110 and the fourth mirror 140 so deformable that by a deformation of the mirror surface of the first mirror 110 combined with a deformation of the mirror surface of the fourth mirror 140 the angle of view of the lens 100 is changed while keeping a position of an image plane 160 of the central shading-free mirror objective 100 remains unchanged in the depth of field. This ensures that, for example, a sensor or detector which is located at the location of the image plane can record a clear image despite different image angles or different zoom states of the objective.

In addition, in front of the first mirror 110 dotted an entrance opening 170 indicated. The entrance Opening can optionally be arranged to let radiation only from a certain area in the lens. In this case, the inlet opening may for example be part of a housing of the mirror objective or a separate optical functional element.

The Use of reflective optical elements allows it wave dependent To prevent aberrations or a chromatic aberration. The mirror objective is therefore in a wide wavelength range of the electromagnetic Spectrum applicable.

2 shows a schematic representation of an optical arrangement of a mirror zoom lens 200 according to an embodiment according to the invention. The mirror zoom lens 200 is constructed so that the beam path 102 along a first construction axis e ₀ of an object 202 at the first mirror 110 so striking that the first construction axis e ₀ and the optical axis 112 of the first mirror include an angle α ₁ , wherein an incidence slot at the point of impact of the first axis of construction e ₀ on the first mirror 110 the optical axis 112 the first mirror 110 equivalent.

According to the law of reflection, the beam path leads 102 along a second construction axis e ₁ , which includes twice the angle α ₁ with the first construction axis e ₀ , to the second mirror 120 , The second construction axis e ₁ and an incidence solder 224 of the second mirror 120 leading to the optical axis 122 of the second mirror 120 is parallel, in a point of impact 225 the second construction axis e ₁ on the mirror surface of the second mirror 120 include an angle α ₂ . The incidence slot in the impact point 225 the second construction axis e ₁ on the second mirror 120 has a distance d ₂ from the optical axis 122 of the second mirror 120 on.

After reflection on the second mirror 120 leads the beam path 102 in turn corresponding to the law of reflection along a third axis of construction e ₂ , which includes with the second axis of construction e ₁ twice the angle α ₂ , to the third mirror 130 , As with the first mirror 110 the third construction axis e ₂ hits the third mirror 130 at the intersection of the optical axis 132 the third mirror 130 with the mirror surface of the third mirror 130 , The incident slot at the point of impact of the third construction axis e ₂ on the third mirror 130 thus corresponds to the optical axis 132 the third mirror 130 , The incidence solder as well as the optical axis 132 the third mirror 130 enclose an angle α ₃ with the third construction axis e ₂ .

After a deflection by twice the angle of incidence α ₃ leads the beam path 102 along a fourth construction axis e ₃ to the fourth mirror 140 , The fourth construction axis e ₃ and an incidence solder 244 the fourth mirror 140 leading to the optical axis 142 the fourth mirror 140 is parallel, in a point of impact 245 the fourth construction axis e ₃ on the mirror surface of the fourth mirror 140 include an angle α ₄ . The optical axis 142 the fourth mirror 140 and the incident slot 244 the fourth mirror 140 have a distance d ₄ to each other.

Along a fifth construction axis e ₄ , which includes twice the angle α ₄ with the fourth construction axis e ₃ , the beam path leads 102 continue to a cover glass 250 and to one behind the cover glass 250 befindli chen sensor or image plane 160 , The fifth construction axis e ₄ and an incidence solder 264 of the cover glass 250 include an angle α ₅ . The incidence solder 264 is parallel to a center axis 262 the picture plane 160 or the sensor and has a distance d ₅ from the center axis 262 the picture plane 160 or the sensor.

The lengths of the first to fifth construction axis (e ₀ to e ₄ ) determine the distance between the optical functional elements.

Furthermore, the dashed lines show 218 at the first mirror 110 and the dashed line 248 at the fourth mirror 140 different deformation states of the mirror surfaces of the two deformable mirrors.

The second mirror 120 represents only a segment of a mirror through the dashed area 228 is shown in its entirety. The dashed area 228 however, it does not have to exist because of the area 228 contains no optically active surfaces. The use of the mirror segment 120 instead of the entire mirror allows the shading arrangement of the mirror of the lens.

The diameters of the first to fourth mirrors are labeled with D ₁ , D ₂ , D ₃ and D ₄ according to the mirror numbers.

The mirror lens 200 and also its global coordinate system is defined by the design axes e ₀ to e ₄ . For defining the construction axes, the first to fourth mirrors are used 110 . 120 . 130 . 140 assumed as plane mirror. The impact points of the design axes on the (assumed) plane mirrors are defined as centroid areas of the (assumed) plane mirror with its border. Rotations are made with the specified angle α ₁ , α ₂ , α ₃ , α ₄ to the incident slot through the centroid of the respective (assumed) plane mirror. Thus, the law of reflection applies. Displacements are made perpendicular to the incidence slot starting from the point of impact, the point resulting from this being regarded as a new center of gravity of the (assumed) plane mirror surface and starting point of an optical axis parallel to the incidence slot.

The domed areas in the first and fourth mirrors 110 . 140 , which are designed as deformable mirror arise when, for example, a membrane is attached to the edge of the (assumed) plane mirror. For the remaining, curved surfaces, the respective centroids are the vertices of the optical elements. The optical axes 112 . 122 . 132 . 142 The elements are parallel to the incidence solders of the (assumed) plane mirror and go through the vertex. Especially at the second mirror 120 then only a section of this shifted mirror image is used. The distances between the individual optical elements are the lengths of the design axes e ₀ to e ₄ .

According to the law of reflection, the term incidence slot refers to the bisecting axis of symmetry between the two construction axes which strike a mirror along the beam path. In the case of a decentered mirror, such as the second mirror 120 and the fourth mirror 140 , the incident slot is not a surface normal of the mirror surface of the respective mirror, since the plane mirror assumed to be a design has been replaced by a curved mirror. The incidence solder is only parallel to the optical axis of the respective mirror, which in turn, however, represents a surface normal of the mirror surface of the corresponding mirror.

Through a decentered use of mirror surfaces, as in 2 for the second mirror 120 and the fourth mirror 140 For example, a central shading-free and compact structure can be supported.

Because a big distance from the fourth mirror 140 to the picture plane 160 or the sensor, referred to as rear focal length, is required, is the lens 200 as retrofocus type with a convex first mirror 110 executed. The second mirror 120 and the fourth mirror 140 have a concave curvature. The third mirror 130 acts as a system shutter and has a slightly convex curvature.

The main symmetry direction of the angle tilt of the individual mirrors is determined by the axes e ₀ , e ₁ , e ₂ , e ₃ and e ₄ . The tilt angles α ₁ , α ₂ , α ₃ and α ₄ are assigned to the respectively corresponding mirror and determine the tilt relative to the axes e ₀ to e ₄ . α ₅ denotes the tilt angle of the image plane 160 or the sensor cover glass 250 ,

The additional lateral displacements occurring in the arrangement between the point of impact of the axes e ₁ to e ₄ on the second mirror 120 and the fourth mirror 140 and the mechanical center axis or the optical axis of the individual mirrors are denoted by d ₂ and d ₄ . The lateral displacement of the sensor cover glass 250 or the picture plane 160 as well as the image sensor receives the name d ₅ . The diameters of the first to fourth mirrors are designated according to the mirror numbers with D ₁ , D ₂ , D ₃ and D ₄ .

The shading-free arrangement is achieved by a compromise of twist angles α ₁ to α ₅ and the distances between the optical components, measured as the length of the axes e ₁ to e ₄ . The twists are made for the first mirror 110 and the third mirror 130 and the picture plane 160 or the sensor including cover glass 250 on the one hand, as well as for the second mirror 120 and the fourth mirror 140 on the other hand, in the opposite direction. For example, the larger the rotation angles of the mirrors, the more difficult it is to correct the astigmatism caused thereby. However, as the angle of rotation decreases, in most cases the distance between the respective mirrors must be increased, which in turn affects the required effective diameter of the mirrors. Furthermore, the rotation angle and distances, for example, from the space requirement of the sensor 160 and cover glass 250 dependent.

The second mirror 120 is arranged so that it is outside a beam of the first mirror 110 lies. In other words, radiation coming from the object 202 at the first mirror 110 does not hit by the second mirror 120 shadowed. In this case, the tilt angle α _{1 of} the first mirror 110 at 22.3 °. The second mirror is opposite to the first mirror rotated by α ₂ = -20.2 ° and decentered simultaneously by d ₂ = 2.2 mm.

Because the fourth mirror 140 also rotated clockwise with α ₄ = -12.6 °, but the distances are not sufficient to shading the image sensor 160 to arrange, is in the aperture plane of the third mirror 130 arranged and rotated at the angle α ₃ = 27.8 ° counterclockwise.

The change in the focal length, for example, by a defined change in the radii of curvature of the first mirror 110 , designated R ₁ , and the fourth mirror 140 Achieved as R ₄ . The first mirror 110 increases or decreases the field angle or angle of view, the fourth mirror 140 corrects the position of the optical focal plane or the image plane 160 and additionally serves to focus. To correct the optical aberrations are, for example, the rotationally symmetric first mirror 110 and the rotationally symmetric fourth mirror 140 designed as conical aspheres. However, the conic constant can be implemented for the entire focal length range as fixed size during zooming. However, the aspheric functional surfaces can also be mathematically described as complete polynomials, polynomial expansion of the spherical or conical surfaces or as so-called free-form surfaces.

Additional aberrations, mainly principled astigmatism and field curvature, may occur with the second mirror 120 and the third mirror 130 Getting corrected. To minimize the complexity of the system, the predominant astigmatism may be corrected, for example, with conical or biconical surfaces. That is, two mutually perpendicular planes have different radii of curvature and / or different conical constants.

In the calculation of in 2 In the embodiment shown, the movement of the vertex of the mirror surface is additionally taken into account when the radius of curvature changes in the case of a diaphragm firmly clamped on the edge as a mirror surface. In this case, the distance between the vertex of the optically active surface and the edge plane increases or decreases with a radius of curvature change. For an aspheric surface, the distance z between the vertex of the optically active surface and the plane through the edge can be determined using the formula:

there D denotes the diameter of the rim, R the radius of curvature and κ the conical Constant.

The central shading-free mirror zoom lens 200 has, for example, a 35mm to 105mm focal length equivalent to 35mm at an initial aperture of 4.5 and includes four mirrors 110 . 120 . 130 . 140 , Furthermore, an image plane 160 or an image sensor with associated sensor cover glass 250 shown. The lens designs an image of an object 202 at the place of the picture plane 160 or the image sensor.

The complete optical characterization of the in 2 shown embodiment can be found in the following tables. Table 1 contains the values of the twist angles and the distances between the elements. Table 2 lists possible parameters for three zoom states. Here, negative radii of curvature are to be understood as convex and positive radii of curvature as concave forms. A conic constant greater than zero results in a flattened ellipsoid according to the formula above. The indication of two values for the radius of curvature and / or the conical constant means that an optical element has a different radius of curvature and / or a different conical constant in two mutually orthogonal directions. Table 1

The Data in the last field of the line with the specified intervals in Table 1 gives 0.6 mm the thickness of the deck glass and 0.7 mm the distance between the coverslip and the image sensor or the image plane at.

The length of the construction axis e ₄ , the decentering d ₅ and the angle α ₅ refer to the position of the cover glass 250 , Since the angle α ₅ and the decentering d ₅ for the image plane 160 or the image sensor the same as for the cover glass 250 are and the thickness of the coverslip 250 and the distance of the cover glass 250 to the picture plane 160 or the image sensor are known, the reference quantities (e ₄ , d ₅ and α ₅ ) of the cover glass 250 easy on reference quantities of the image plane 160 be converted.

The cover glass 250 and the image sensor at the location of the image plane 160 are optional components and not an integral part of the described mirror lens. Table 2 angle of view 38 ° × 49 ° 26 ° × 34 ° 13 ° × 17 ° focal length f _min = 5.3 mm f _center = 7.9 mm f _max = 15.8 mm f-number 4.5 4.8 5.7 Radius of curvature R mirror 110 R ₁ = -17.8 mm R ₁ = -26.7 mm R ₁ = -51.7 mm mirror 120 y: R _2y = 65.8 mm x: R _2x = 66.4 mm mirror 130 y: R _3y = -113.6 mm x: R _3x = -128.1 mm mirror 140 R ₄ = 41.9 mm R ₄ = 44.1 mm R ₄ = 51.7 mm Conic constant κ mirror 110 κ ₁ = 1.0 mirror 120 y: κ _2y = 1.5 x: κ _2x = 1.0 mirror 130 y: κ _3y = 48.0 x: κ _3x = 62.3 mirror 140 κ ₄ = 0.6

3 shows a schematic representation of the in 2 shown mirror zoom lens with a Focal length of 5.3 mm according to an embodiment of the invention. The construction of the mirror zoom lens 300 corresponds to the optical arrangement in 2 is shown. As an example, the ray bundles 302 . 304 . 306 drawn for three different field points or object points. It is the path of the three different bundles of rays 302 . 304 . 306 through the lens 300 to the picture level 160 or the image sensor shown.

4 shows a spot diagram 400 of in 3 shown zoom lens with a focal length of 5.3 mm (also known as wide angle). A spot diagram illustrates the geometric image of a point-like object and is therefore an indication of the quality of a lens. The construction of a spot diagram starts with a single object point that emits a plurality of monochromatic beams or a beam. This radiation uniformly hits an entrance pupil of the objective. This beam is then tracked by applying trigonometry through the lens to the image plane. The sum of points at which the individual rays of the beam meet the image plane represents the spot diagram.

In 4 These are three examples of three different object angles 412 . 422 . 432 shown. It is in box 1 (at reference numerals 410 shown) a beam incident at an object angle of 0 °, which corresponds to an image of a point-like object in the image field center. In box 2 (as with reference numerals 420 a beam is shown which is incident at an object angle of -12.3 ° and -9.5 °, which corresponds to an image of a point-like object in the central image field. By using a rectangular image format, the specification of two mutually orthogonal angles is necessary. Furthermore, in box 3 (as with reference numerals 430 shown) a beam incident at an object angle of -24.6 ° and -19 °, which corresponds to an image of a point-like object in a corner of the image field.

In addition, in each of the three fields is a circle 440 with a radius equal to the Airy radius 470 corresponds, drawn. This circle 440 , also called Airy disc, represents the smallest possible representation of a point-like object through the lens. That is, the higher the number of points of the spot diagram within the circle 440 is, the better the quality of the lens.

Furthermore, in each of the three fields is an IMA parameter 414 . 424 . 434 specified. The IMA parameter gives a value for the distance between the center of the image plane or the center of the Airy disk and the location of the spots in the image plane.

Additionally, for the three fields, values are for an RMS radius 450 (RMS: "route means square") and a GEO radius 460 (GEO: geometric maximum value).

The spot diagram 400 shows for the in 3 A zoom lens with a focal length of 5.3 mm, a typical image quality for commercial photo lenses.

5 shows a schematic representation of the in 2 shown zoom lens with a focal length of 7.9 mm according to an embodiment of the invention. As in 3 is the way of three different beams 502 . 504 . 506 through the lens 500 to the picture level 160 or the image sensor shown.

6 shows matching the in 5 shown zoom lens with a focal length of 7.9 mm (also referred to as normal angle) a spot diagram 600 for three different object angles 612 . 622 . 632 ,

The spot diagram shows for the in 5 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

7 shows a schematic representation of the in 2 shown 15.8 mm focal length zoom lens according to an embodiment of the invention. As in 3 is the way of three different beams 702 . 704 . 706 through the lens 700 to the picture level 160 or the image sensor shown.

8th shows matching the in 7 15.8 mm focal length zoom lens (also referred to as telephoto) is a spot diagram 800 for three different object angles 812 . 822 . 832 ,

The spot diagram shows for the in 7 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

The 2 . 3 . 5 and 7 show the mirror zoom lens and the optical system with the data of Tables 1 and 2.

9 shows a schematic representation of an optical arrangement of a telephoto zoom lens 900 according to an embodiment according to the invention. The optical arrangement 900 is similar to the arrangement as in 2 is shown.

The mirror zoom lens again comprises four mirrors, the first mirror 110 and the fourth mirror 140 are rotationally symmetric and deformable. The shown central shading-free mirror zoom lens 900 has an equivalent focal length of 70 mm to 210 mm with an initial aperture of 4.5. As well as in 2 Lens shown is the mirror zoom lens 900 as retrofocus type with a convex first mirror 110 executed. The second mirror 120 and the fourth mirror 140 have a concave curvature. The third mirror 130 acts as a system shutter and has a slightly convex curvature. The second mirror 120 has a decentered conical shape.

Furthermore, the mirror zoom lens differs 900 from the in 2 shown lens by the distances of the optical elements to each other (e ₁ to e ₄ ), by the rotation of the optical elements to each other (α ₁ to α ₅ ), by the decentering of the optical elements from their optical axes or mechanical center axes (d ₂ to d ₅ ) as well as the shape of the first to fourth mirror, since the parameters are adapted to the selected focal length range (70 mm to 210 mm) in order to minimize image errors.

The complete optical characterization of the mirror zoom lens 900 can be found in the following tables. Table 3 contains the values of the twist angles and the distances between the elements as shown in 9 are identified by the reference numerals. Table 4 lists the necessary parameters for three zoom states. Here, negative radii of curvature are to be understood as convex and positive radii of curvature as concave forms. A conic constant greater than zero results in a flattened ellipsoid according to the formula above. Table 3

The data in the last field of the line with the specified distances in Table 3 gives the thickness of the cover glass at 0.6 mm and the distance between the cover glass and the image sensor at 0.7 mm Image plane.

The length of the construction axis e ₄ , the decentering d ₅ and the angle α ₅ refer to the position of the cover glass 250 , Since the angle α ₅ and the decentering d ₅ for the image plane 160 or the image sensor the same as for the cover glass 250 are and the thickness of the coverslip 250 and the distance of the cover glass 250 to the picture plane 160 or the image sensor are known, the reference quantities (e ₄ , d ₅ and α ₅ ) of the cover glass 250 easy on reference quantities of the image plane 160 be converted.

The cover glass 250 and the image sensor at the location of the image plane 160 are optional components and not an integral part of the described mirror lens. Table 4 angle of view 9.5 ° × 12.3 ° 6.5 ° × 8.8 ° 3.2 ° × 4.3 ° focal length f _min = 10.5 mm _center = 15.8 mm f _max = 31.5 mm f-number 4.5 4.9 6.0 Radius of curvature R mirror 110 R ₁ = -38.4 mm R ₁ = -56.7 mm R ₁ = -109.1 mm mirror 120 R ₂ = 92.0 mm mirror 130 y: R _3y = -132.7 mm x: R _3x = -137.8 mm mirror 140 R ₄ = 60.4 mm R ₄ = 64.5 mm R ₄ = 80.7 mm Conic constant κ mirror 110 κ ₁ = 1.2 mirror 120 κ ₂ = 0.5 mirror 130 y: κ _3y = 19.3 x: κ _3x = 19.2 mirror 140 κ ₄ = 0.6

10 shows a schematic representation of the in 9 10.5 mm focal length zoom telephoto zoom lens according to an embodiment of the invention. As in 3 is the way of three different beams 1002 . 1004 . 1006 through the lens 1000 to the picture level 160 or the image sensor shown.

11 shows matching the in 10 The telephoto zoom lens with a focal length of 10.5 mm is a spot diagram 1100 for three different object angles 1112 . 1122 . 1132 ,

The spot diagram shows for the in 10 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

12 shows a schematic representation of the in 9 shown 15.8 mm focal length telephoto zoom lens according to an embodiment of the invention. As in 3 is the way of three different beams 1202 . 1204 . 1206 through the lens 1200 to the picture level 160 or the image sensor shown.

13 shows matching the in 12 shown telephoto zoom lens with a focal length of 15.8 mm a spot diagram 1300 for three different object angles 1312 . 1322 . 1332 ,

The spot diagram shows for the in 12 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

14 shows a schematic representation of the in 9 shown telephoto zoom lens with a focal length of 31.5 mm according to an embodiment of the invention. As in 3 is the way of three different beams 1402 . 1404 . 1406 through the lens 1400 to the picture level 160 or the image sensor shown.

15 shows matching the in 14 shown telephoto zoom lens with a focal length of 31.5 mm a spot diagram 1500 for three different object angles 1512 . 1522 . 1532 ,

The spot diagram shows for the in 14 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

The 9 . 10 . 12 and 14 show the mirror zoom lens or the optical system with the data of Tables 3 and 4.

16 shows a schematic representation of an optical arrangement of a super telephoto mirror zoom lens 1600 according to an embodiment according to the invention. The super telephoto mirror zoom lens 1600 is similar to the one in 2 shown mirror zoom lens and in turn includes four mirrors. The objective 1600 has an equivalent focal length of 200 mm to 600 mm and an initial aperture of 6.5 on the small picture. The first mirror 110 and the fourth mirror 140 are again designed as rotationally symmetric, deformable mirrors.

Unlike the in 2 and in 9 shown embodiments, in the lens shown here 1600 the first mirror 110 a concave curvature and the second mirror 120 a convex curvature. The third mirror again acts as a system shutter and has a slightly concave curvature.

Furthermore, the mirror zoom lens differs 1600 from the in 2 shown lens by the distances of the optical elements to each other (e ₁ to e ₄ ), by the rotation of optical elements to each other (α ₁ to α ₅ ), by the decentering of the optical elements of their optical axes or mechanical center axes (d ₂ to d ₅ ) as well as the shape of the first to fourth mirrors, since the parameters are adapted to the selected focal length range (200 mm to 600 mm) to minimize image errors.

The complete optical characterization of the super telephoto mirror zoom lens 1600 can be found in the following tables. Table 5 contains the values of the twist angles and the distances between the elements. Table 6 lists the necessary parameters for three zoom states. Negative radii of curvature are to be understood as convex and positive radii of curvature as concave forms. A conic constant greater than zero results in a flattened ellipsoid according to the formula above.

The second mirror 120 is in the opposite direction (in comparison with the in 2 and 9 decentered lenses) decentered. Thus, the d2 decimation receives a negative sign. Table 5

The Data in the last field of the line with the specified intervals in Table 5 gives 0.6 mm the thickness of the cover glass and 0.7 mm the distance between the coverslip and the image sensor or the image plane at.

The length of the construction axis e ₄ , the decentering d ₅ and the angle α ₅ refer to the position of the cover glass 250 , Since the angle α ₅ and the decentering d ₅ for the image plane 160 or the image sensor the same as for the cover glass 250 are and the thickness of the coverslip 250 and the distance of the cover glass 250 to the picture plane 160 or the image sensor are known, the reference quantities (e ₄ , d ₅ and α ₅ ) of the cover glass 250 easy on reference quantities of the image plane 160 be converted.

The cover glass 250 and the image sensor at the location of the image plane 160 are optional components and not an integral part of the described mirror lens. Table 6 angle of view 3.4 ° × 4.6 ° 1.7 ° x 2.3 ° 1,1 ° × 1,5 ° focal length f _min = 30 mm _center = 60 mm f _max = 90 mm f-number 6.5 8.2 10.0 Radius of curvature R mirror 110 R ₁ = ∞ R ₁ = 316.0 mm R ₁ = 236.8 mm mirror 120 y: R _2y = -236.9 mm x: R _2x = -233.7 mm mirror 130 y: R _3y = 407.3 mm x: R _3x = 406.8 mm mirror 140 R ₄ = 72.5 mm R ₄ = 99.0 mm R ₄ = 157.2 mm Conic constant κ mirror 110 κ ₁ = 0.4 mirror 120 y: κ _2y = 19.3 x: κ _2x = 39.7 mirror 130 y: κ _3y = 932.6 x: κ _3x = -890.0 mirror 140 κ ₄ = 0.6

17 shows a schematic representation of the in 16 shown super-telephoto zoom lens with a focal length of 30 mm according to an embodiment of the invention. As in 3 is the way of three different beams 1702 . 1704 . 1706 through the lens 1700 to the picture level 160 or the image sensor shown.

18 shows matching the in 17 shown telephoto zoom lens with a focal length of 30 mm a spot diagram 1800 for three different object angles 1812 . 1822 . 1832 ,

The spot diagram shows for the in 17 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

19 shows a schematic representation of the in 16 shown supertele mirror zoom lens with a focal length of 60 mm according to an embodiment of the invention. As in 3 is the way of three different beams 1902 . 1904 . 1906 through the lens 1900 to the picture level 160 or the image sensor shown.

20 shows matching the in 19 shown telephoto zoom lens with a focal length of 60 mm a spot diagram 2000 for three different object angles 2012 . 2022 . 2032 ,

The spot diagram shows for the in 19 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

21 shows a schematic representation of the in 16 shown super-telephoto mirror zoom lens with a focal length of 90 mm according to an embodiment of the invention. As in 3 is the way of three different beams 2102 . 2104 . 2106 through the lens 2100 to the picture level 160 or the image sensor shown.

22 shows matching the in 21 shown telephoto zoom lens with a focal length of 90 mm a spot diagram 2200 for three different object angles 2212 . 2222 . 2232 ,

The spot diagram shows for the in 21 Mirror zoom lens shown a common for commercial photo lenses imaging performance.

The 16 . 17 . 19 and 21 show the optical system and the supertele mirror zoom lens with the data of Tables 5 and 6, respectively.

23 shows a schematic representation of an image recording system 2300 with a mirror zoom lens and two image sensors according to an embodiment of the invention. The lens of the image acquisition system 2300 is based on the calculation or the optical arrangement of in 2 shown mirror zoom lens.

The two image sensors 2361 . 2362 have a different spectral sensitivity. As a result, for example, a multi-spectral camera with two image sensors 2361 . 2362 will be realized. As already described, this has in 2 Mirror lens shown no chromatic aberrations. Therefore, this lens design or lens assembly can be used for a very broad wavelength range. For this purpose, for example, the spectral sensitivity of the recording sensors or image sensors used and the reflectivity of the mirror layers or mirror surfaces are matched to the spectral requirements of the application in the foreground. Using, for example, broadband-reflecting metal layers (eg aluminum, silver or the like) or dielectric layers, images in different spectral ranges can be recorded with almost the same quality.

This is the beam path to the fourth mirror 140 with a beam splitter plate 2370 , which is provided with a spectrally selective layer, divided and the two detectors 2361 . 2362 guided. This results in two images in different spectral ranges on the two image sensors 2361 . 2362 , For example, a detector 2361 be sensitive in the visible spectral range (VIS), while the second sensor or detector 2362 is designed for the infrared spectral range (IR).

An application for the image recording system or the mirror zoom objective with two image sensors is possible, for example, in the field of multispectral field monitoring. Conventional field monitoring systems often operate either in the visible or in the infrared spectral range, since the optics used there often have refractive components with chromatic aberrations and are therefore limited to limited spectral ranges. Here the described mirror lens or the image acquisition system offers 2300 clear advantages. Being able to take pictures with almost consistently high quality within a broad spectral range due to the non-existent wavelength-dependent aberrations creates additional functionality in combination with a zoom function and the use of more than one image sensor for different spectral ranges. Due to the use of deformable mirrors for focal length adjustment and the resulting high stability and small size is the described lens or image recording system 2300 For example, suitable for field monitoring tasks in a harsh environment.

24 shows a schematic representation of an image recording system 2400 with a mirror zoom lens with combined cover glass 2480 according to an embodiment according to the invention. The image acquisition system 2400 or camera system is in turn based on the in 2 shown optical arrangement of a mirror zoom lens.

Here, however, the aperture mirror or the third mirror 130 with the sensor cover glass 250 to a new optical functional element 2480 combined. This, in contrast to the in 2 shown mirror zoom lens, the optical axis 132 of the mirror 130 and the optical axis 2452 of the cover glass 250 be parallel. The combined cover glass 2480 For example, not only does it have a toric curvature on a part of its surface, it is also laterally partially mirrored and, in most cases, has to be mounted with high mounting accuracy together with the sensor 160 be positioned. It is also possible to combine by mounting the third mirror 130 on a suitable coverslip 250 to reach.

By combining the third mirror 130 with the cover glass 250 may, for example, be the number of components necessary for the image acquisition system 2400 or reduced camera system and a more compact design are possible.

25 shows a schematic representation of an image recording system 2500 with a mirror zoom lens and an additional offner relay arrangement according to an embodiment according to the invention. The image acquisition system 2500 or camera system is also based on the in 2 shown optical arrangement for a mirror zoom lens.

For example, in an application in the infrared spectral range, a so-called cold stop is often required to suppress stray light. This is usually placed in an exit pupil of the system. Since the system described above is a nearly telecentric arrangement and thus has its exit pupil at infinity, this imaging system will 2500 an intermediate picture 2509 necessary. This is rea with the help of an arrangement called Relay opt which, in addition to a real image of the pupil, also depicts the image of the intermediate image 2509 on the image sensor 160 ensures. It should be noted that it is the intermediate image 2509 not an intermediate image of the mirror zoom lens, but an intermediate image of the image pickup system that includes the mirror zoom lens and the additional offner relay array.

In order not to unnecessarily degrade the imaging quality of the system, this relay optics requires long focal lengths compared to the system described above. Some relay optics approaches are exemplified in "J. Michael Rodgers, Unobscured mirror designs, International Optical Design Conference 2002, Proc. of SPIE vol. 4.832 ". When using, for example, a classic Offner structure, such. B. in the US 3748015 A shown with the additional mirrors 2510 and 2511 Due to the focal length ratios and distances, the exit pupil of the imaging system lies in the plane of the convex mirror 2511 the offner relay system.

Some embodiments according to the invention refer to a mirror zoom lens with two deformable ones Mirror, a telephoto zoom lens with two deformable mirrors, a super-telephoto zoom lens with two deformable mirrors, an image recording system or a multi-spectral camera with two image sensors, a mirror zoom lens and two image sensors different spectral sensitivities, an image acquisition system or a camera system with combination of the third mirror and the sensor cover glass, a mirror zoom lens with combined cover glass, a mirror zoom lens with additional Offner relay arrangement or an image acquisition system or a camera system with a mirror zoom lens with additional Interim picture for the infrared spectral range.

Further embodiments according to the invention refer to a mirror zoom lens for use in one Camera system designed as a helmet camera for rescue workers is. Again, the opportunity offers High-quality multispectral imaging with a lens in conjunction with several image sensors for different spectral ranges clear advantages. The zoom functionality allows, for example, the Rescue force through visual examination smoked by camera or filled with water vapor inside rooms crashed scan without the rescuer groping groping through the building got to. With that you can z. For example, accident victims can be found more easily without exposing the rescuer to unnecessary dangers. This application requires robust, low volume systems. Through the use of deformable mirrors for focal length adjustment can these requirements are met by the described mirror zoom lens.

Some embodiments according to the invention refer to an application of a mirror zoom lens in the area of driver assistance systems. Car rides in the fog pose today still an elevated one Accident risk. The obstructed view often makes obstacles appear too late. A possibility the driver assistance is a camera that is in the part of the infrared Spectral range works in which fog is transparent and thus an increased Visibility allows. The zoom function also allows an adaptation of the image angle to circumstances in the environment, such as B. the street width. Here offers the use of deformable mirrors for focal length adjustment significant benefits for the use in the automobile. For example, the greater stability and the Small construction volumes have a positive effect here.

Further embodiments according to the invention refer to an application of a mirror zoom lens in the area remote sensing, such as the visual and multispectral Aerial photograph. In the course of progressive miniaturization increasingly unmanned small aircraft are used. Also here Very high demands are made on the camera and the lens the optical resolution and mechanical stability. Therefore, it is beneficial instead of the previous relocatable optical components to realize the zoom functionality, deformable Elements with elevated To use robustness.

Further embodiments according to the invention relate to an application of a mirror objective in spatially resolving spectrometers, hyper or multi-spectral imaging systems (hyper or multispectral imaging system). These systems consist of a lens and, for example, a system for active or passive spectral modulation of the image, referred to as an imaging spectrograph or imaging spectrometer. The spatial spectral composition of the image may be determined by active modulation (eg, Fourier transform spectrometer, Hadamard transform spectrometer), passive modulation (eg, passive Hadamard transform spectrometer), spectral splitting (e.g. Grating spectrometer) and / or local and / or spectral filtering (eg filter wheel spectrometer, acousto-optical-transformation spectrometer, spectrometer with Fabry-Perot interferon meter). The mirror zoom lens offers the advantage of a good spectral broadband imaging quality, a very good scattered light behavior (elimination of ghosting), possible use in different wavelength ranges (eg ultraviolet, visible and / or infrared spectral range) and the elimination of expensive broadband antireflective coatings. In addition, the functionality of the mirror lens offers the possibility to optimally adapt the lower spatial resolution of the systems compared to normal cameras to the image area to be acquired.

When Ghost pictures are called blurred or ghostly pictures bright light sources caused, for example, by reflections from lens surfaces become.

Further embodiments according to the invention refer to using a mirror zoom lens in mobile devices. The advantages described make applications addressable, such as for example in mobile devices, which are not achievable with the prior art.

at some embodiments according to the invention is used to set the desired System focal length first the first mirror preset according to the desired system focal length and then focus the desired object with the fourth mirror. there the deformable first mirror can be provided with a sensor, a control of the curvature state allows. This sensor can, for. B. be designed as strain gauges. By means of a look-up table (look-up table) can thus the desired curvature be pre-set according to the required system focal length. The second deformable mirror is adjusted so that the object sharp imaged on the sensor or detector. This can for example a contrast method or an additional autofocus sensor used become.

at some embodiments according to the invention can an existing, focal length dependent distortion (geometric Aberration) of the shadow-free mirror zoom lens their knowledge with a software subsequently be corrected in the image.

Further embodiments according to the invention show constructions for the deformable mirrors, which at a change in curvature, the position of the apex change, which in connection with a Schiefspiegler a lateral shift the image on the detector result, but in the described Mirror lenses remains sufficiently small.

Some the embodiments according to the invention include suitable for the reduction of stray light in the beam path Shields, such as screens and / or beam traps.

Further embodiments according to the invention comprise a deformable mirror which only has one actuator for change the radius of curvature having. Such deformable mirrors have a compact construction and a simple control on.

A description of a positioning of aspherical and possibly not symmetrical mirror surfaces in the beam path of a Schiefspiegler proves to be complicated compared to rotationally symmetric systems. Since in the end no optical axis or no common optical axis can be defined for the entire objective and, in addition, a surface element acting as a mirror itself does not necessarily have to have symmetries or preferred directions, it is difficult to specify distances and tiltings of different optical elements unambiguously or independently of the coordinates , For a partial determination of the position of the optical surfaces to each other in the following, as in 26a and 26b shown, one reference point each 2610 on a surface and a directional vector associated with the surface 2620 Are defined.

From each object point, a beam bundle delimited, for example, by an aperture stop of the optical system emerges, which occupies a specific area corresponding to the bundle cross section on the different optical surfaces. This cross-section is generally different for different object points according to location and size on a mirror surface. The totality of all bundle cross-sections on one surface forms the optically active component 2630 the functional area. The optically active surface 2630 is now in such a way that the focus 2650 Contains the area projected that the area of the projection occupies a maximum. The plane projection surface thus formed then becomes along the direction of its normal vector 2620 shifted so that the centroid 2650 just in the original optically active area 2630 lies. In this way, the optically active part 2630 the surface and thus also the mirror surface itself a reference point 2610 and via the normal vector 2620 the projection surface an orientation, ie a direction vector 2620 in the room, assigned. The 26a and 26b thus show a definition of a reference point 2610 and a directional vector 2620 for the optically active surface 2630 an optical functional element.

With the help of reference points, as in 27 and 28 shown a reference plane 2710 which are the reference points 2730 . 2740 . 2750 contains at least three mirrors, are constructed to establish a preferred direction with respect to the image field. With an angle between the direction vector of a mirror and a surface normal 2720 the common reference plane 2710 then becomes the tilt relative to the reference plane 2710 established. This is in the 27 and 28 for the first to fourth mirror 110 . 120 . 130 . 140 through the angles β ₁ , β ₂ , β ₃ , β ₄ and the direction vectors r → 1 , r → 2 , r → 3 , r → 4 shown.

27 shows as an example a schematic representation of an optical arrangement for the definition of reference quantities, in which the angles β ₁ to β _{4 have} every 90 °. The direction vectors r → 1 to r → 4 are thus in the reference plane 2710 passing through the reference point 2730 the first mirror 110 , the reference point 2740 the third mirror 130 and the reference point 2750 the fourth mirror 140 is spanned. Next to the first to fourth mirror shows 27 an arrangement of a sensor cover glass 250 ,

In contrast to 27 shows 28 as an example, an arrangement of the first to fourth mirror 110 . 120 . 130 . 140 in which the angles β ₁ to β _{4 are} not equal to 90 ° and thus not in the reference plane 2710 lie. The reference plane, in turn, passes through the reference points 2730 . 2740 . 2750 of the first, third and fourth mirror spanned. In addition, the arrangement of a sensor cover glass 250 and an image sensor 160 shown.

The rotation within the common reference plane 2710 can be determined by an additional angle between a main symmetry direction in the plane and the direction vector.

To Favoring an implementation for an optics bill can slightly modified sizes for Location description of the components of the mirror lens used become. However, this fact affects the above Definitions are not, since a clear relationship between the corresponding sizes.

Some embodiments according to the invention correspond in their arrangement of in 27 shown arrangement. In 27 is spatially shown that the angles β ₁ to β ₄ between the normal 2720 the through the reference points 2730 . 2740 . 2750 spanned reference plane 2710 and the direction vectors r → 1 to r → 4 have a value of 90 °. Thus lie the directional vectors r → 1 to r → 4 in a plane or in the reference plane 2710 , In the 1 to 25 illustrated embodiments correspond in their arrangement in 27 shown ratios with angles β ₁ to β ₄ of 90 °.

In some embodiments according to the invention, the angles β ₁ to β ₄ , as in FIG 28 shown between the normal 2720 the through the reference points 2730 . 2740 . 2750 spanned reference plane 2710 and the direction vectors r → 1 to r → 4 a value not equal to 90 °. This is the direction vectors r → 1 to r → 4 not in a plane or in the reference plane 2710 , Such an arrangement may, for example, allow a more compact structure, on the other hand, this arrangement may result in larger aberrations.

Some embodiments according to the invention comprise a central shading-free mirror lens with variable angle of view consisting of a first mirror or a first deformable mirror, a second mirror or a second deformable or rigid mirror, a third mirror or a third either deformable or rigid mirror, and a fourth mirror or a fourth deformable mirror, wherein the angles β ₁ to β ₄ between a normal 2720 the reference plane spanned by three of the four reference points 2710 and the direction vectors r → 1 to r → 4 include an amount between 60 ° and 120 °.

According to one aspect, some embodiments according to the invention include a central shading-free mirror lens having a variable angle of view consisting of a first mirror or a first deformable mirror 110 , a second mirror or a second rigid mirror 120 whose surface is aspheric, a third mirror or a third rigid mirror 130 , whose surface is aspheric, and a fourth mirror or a fourth deformable mirror 140 , wherein the angles β ₁ to β ₄ between the normal 2720 the reference plane spanned by three of the four reference points 2710 and the directional vectors r → 1 to r → 4 include an amount between 60 ° and 120 °.

According to one Another aspect may be in the mirror lens, the deformation of the deformed executed Mirror from a change the radius of curvature and / or the conical constant and / or higher orders.

Corresponding In another aspect, the deformable mirror may be the mirror lens fourth mirror for all deformation states concave curved be.

According to one Another aspect may be in the mirror lens of the third mirror have the function of an aperture stop.

Corresponding In another aspect, the mirror may be the third mirror a toric or biconical area exhibit.

In another aspect, in the mirror objective, the first mirror or first deformable mirror may be planar or convex and the amount of its radius of curvature greater than 0.9 times the minimum system focal length and having a conic constant greater than or equal to zero wherein the length of the design axis (e ₁ ) between the first mirror and the second mirror is between 1 and 10 times the minimum system focal length. In addition, the second mirror or aspheric second mirror is concave and the amount of its radius of curvature is between 2 times and 20 times the minimum system focal length and the amount of lateral displacement (d ₂ ) of its mechanical center axis from the point of impact of the design axis (e ₁ ) is less than 2 times the minimum system focal length, the length of the design axis (e ₂ ) between the second mirror and the third mirror being between 0.5 and 6 times the minimum system focal length, and the length of the Design axis (e ₃ ) between the third mirror and the fourth mirror is between 0.5 times and 6 times the minimum system focal length. Furthermore, the fourth mirror or deformable fourth mirror is concave and the amount of its radius of curvature is between 1 and 15 times the minimum system focal length and has a conic constant greater than or equal to 0, the length of the Design axis (e ₄ ) between the fourth mirror and the sensor cover glass between 0.5 times and 10 times the minimum system focal length.

According to another aspect, in the mirror objective, the first mirror or the first deformable mirror may be planar or concave and the amount of its radius of curvature may be greater than 0.9 times the minimum system focal length and have a conic constant greater than or equal to zero wherein the length of the design axis (e ₁ ) between the first mirror and the second mirror is between 1 and 10 times the minimum system focal length. In addition, the second mirror or aspheric second mirror is convex and the amount of its radius of curvature is between 2 times and 20 times the minimum system focal length and the amount of lateral displacement (d ₂ ) of its mechanical center axis from the point of impact of the design axis (e ₁ ) is less than 2 times the minimum system focal length, the length of the design axis (e ₂ ) between the second mirror and the third mirror being between 0.5 and 6 times the minimum system focal length, and the length of the Design axis (e ₃ ) between the third mirror and the fourth mirror is between 0.5 times and 6 times the minimum system focal length. Further, the fourth mirror or deformable fourth mirror is concave and the amount of its radius of curvature is between 1 and 15 times the minimum system focal length and has a conic constant greater than or equal to 0, the length being the design axis (e ₄ ) between the fourth mirror and the sensor cover glass is between 0.5 times and 10 times the minimum system focal length.

According to one Another aspect may be the change in the mirror objective for focusing the curvature of the fourth mirror.

Corresponding Another aspect may be in the mirror lens immediately before the third mirror or aspherical rule third mirror one in her mouth be arranged variable aperture.

According to one another aspect in the mirror objective, the mirroring layers of the first to fourth mirror metallic layers, dielectric layers or dielectric layer stacks or a combination of metallic ones and dielectric layers.

According to another aspect, in the mirror objective, the spectral reflectivity of the Ver mirror layers to be adapted to a wavelength range.

According to one Another aspect may be at least one deformable in the mirror lens Mirror have at least one sensor that provides information about his Deformation state supplies.

Corresponding Another aspect may be in the mirror lens in the beam path at least one further diaphragm, which does not act as an aperture diaphragm, be shaped and arranged so that stray light is reduced. The additional aperture can be used as a separate optical component be designed or for example by internal surfaces of a housing be realized the mirror lens. The aperture can be stray light absorbing surfaces exhibit. However, it is also possible, for example, surfaces of the panel or the housing with form reflective layers to scatter light on others surfaces divert the then stray light absorbing layers exhibit.

According to one another aspect in the mirror lens in front of the first mirror and / or after the Fourth mirror further optical functional elements may be arranged.

Corresponding another aspect in the case of the mirror objective, the optical functional elements are reflective and / or have refractive and / or diffractive properties and / or the intensity and / or the polarization and / or the spectral properties influence the electromagnetic radiation, so for example Mirrors, windows, filters, polarizers and / or lenses, prismatic body and / or diffraction gratings and / or photonic crystals.

According to one another aspect in the mirror lens between the first to fourth mirror be arranged further plane optical functional elements.

Corresponding another aspect in the case of the mirror objective, the plane-optical functional elements mirror and / or windows and / or filters and / or polarizers and / or prismatic body be.

Some embodiments according to the invention refer to an image acquisition system consisting of a central shading free Mirror lens with variable angle of view and at least one sensor or detector for detecting electromagnetic radiation with at least an element and readout electronics for the sensor or detector.

Corresponding In one aspect, some embodiments include embodiments of the invention an image pickup system in which the beam path in front of the image sensor with a beam splitter spectrally selective to at least one other Image sensor is steered.

According to one another aspect may be the third mirror in the image pickup system and the coverslip combined to form an optical component.

Corresponding In another aspect, the image capture system may include an autofocus sensor exhibit.

Some embodiments according to the invention refer to a spatially resolving Spectrometer or a hyper-spectral imaging system (Hyper-Spectral Imaging System) or a multi-spectral imaging system (Multi-spectral imaging system) consisting of a central shading-free mirror lens with variable field of view and at least one system and / or component and / or module for active modulation and / or passive modulation and / or filtering the spectral and / or local radiation distribution and a detector for electromagnetic radiation with at least one element for image acquisition.

at some embodiments become the image sensor or detector and the term image plane for the same Element used as an image sensor normally at the location of Image plane is arranged. The image sensor is not mandatory Part of the mirror zoom lens. For example, if the mirror zoom lens becomes used in an image capture system, an image sensor can also only at one located after the image plane of the mirror zoom lens be arranged further image plane of the image recording system. The Image plane of the mirror zoom lens then provides an intermediate image plane of the image recording system.

Finally, it should be mentioned that under the term used above the system focal length or Total focal length of a lens, for example, the distance of the image-side main plane to the image-side focal point can be understood.

Furthermore, the optical axis of a rotationally symmetric surface is equal to an axis of symmetry that passes through the vertex and the center of curvature of the surface. For areas that do not have an axis of symmetry, the optical axis may be defined by a direction vector, as in FIG 26 shown to be defined. The optical axis is also referred to as mechanical center axis.

Of the Term Image field refers to a part of the image plane, that of the image circle is limited, namely the part of the image plane onto which the lens images with sufficient image quality. The image field does not necessarily have to be circular.

Under depth of field one understands the area in the object space in front of and behind a focused one Object in which an image is sharply displayed. For example this is the case as long as a point-like object is imaged onto a surface becomes smaller than a pixel or pixel cluster of an image sensor is.

Under the term "wavelength independent" is in To understand the relationship with the described mirror zoom lens, that is in a wide range of electromagnetic Wave spectrum, for example, the ultraviolet, visible and infrared spectral range, no detectable wavelength-dependent aberrations result.

Especially It should be noted that, depending on the circumstances, the scheme of the invention or parts of the image correction can also be implemented in software can. The implementation can be done on a digital storage medium, in particular a floppy disk or a CD with electronically readable control signals done so interact with a programmable computer system can that the corresponding procedure is carried out. Generally exists The invention thus also in a computer program product on a machine readable carrier stored program code for carrying out the method according to the invention, when the computer program product runs on a computer. In in other words, Thus, the invention can be considered as a computer program with a program code to carry out of the method realized when the computer program product runs on a computer.

Claims (28)

Central shading-free mirror objective ( 100 ; 200 ; 300 ; 500 ; 700 ; 900 ; 1000 ; 1200 ; 1400 ; 1600 ; 1700 ; 1900 ; 2100 ) with a variable field of view, comprising: a first mirror ( 110 ) designed as a deformable mirror; a second mirror ( 120 ) whose mirror surface has an aspherical shape; a third mirror ( 130 ) whose mirror surface has an aspherical shape; a fourth mirror ( 140 ) arranged as a deformable mirror, wherein the first to fourth mirrors are arranged so that at least two mirrors of the first to fourth mirrors have a different optical axis (Fig. 112 . 122 . 132 . 142 ) and that a folded beam path from the first mirror ( 110 ), via the second mirror ( 120 ) and the third mirror ( 130 ) to the fourth mirror ( 140 ), wherein the first to fourth mirror are arranged and shaped so that in the beam path ( 102 ) between the first mirror ( 110 ) and the fourth mirror ( 140 ) is not an intermediate image plane, and wherein the first mirror ( 110 ) and the fourth mirror ( 140 ) are deformable so that by a deformation of the mirror surface of the first mirror ( 110 ) combined with a deformation of the mirror surface of the fourth mirror ( 140 ) the angle of view of the lens is changed while a position of an image plane ( 160 ) of the central shading-free mirror lens remains unchanged in a range of a depth of field. A central shading-free mirror with a variable field of view according to claim 1, wherein the first mirror ( 110 ) and the fourth mirror ( 140 ) have a rotationally symmetric mirror surface. Central shading-free mirror lens with a variable angle of view according to claim 1 or 2, the only reflective imaging or distracting elements includes. A central shading-free mirror lens with a variable field of view according to any one of claims 1 to 3, wherein only the first and the fourth mirror for changing the image angle of the lens by the deformation of the first mirror ( 110 ) and the deformation of the fourth mirror ( 140 ), where the position of the image plane ( 160 ) of the central shading-free mirror lens remains unchanged within the depth of field. A central shading-free mirror lens with a variable field of view according to one of claims 1 to 4, wherein the second mirror ( 120 ) or the third mirror ( 130 ) have a biconical or toric shape. A central shading-free mirror lens with a variable field of view according to one of claims 1 to 5, wherein the second mirror ( 120 ) and the third mirror ( 130 ) are rigid mirrors. Central shading-free mirror objective ( 200 ; 900 ) with a variable field of view according to one of claims 1 to 6, having the following further features: the first mirror ( 110 ) having a plane or convex mirror surface whose magnitude of the radius of curvature is greater than 0.9 times the minimum system focal length and whose conical constant is greater than or equal to zero; a first construction axis (e ₀ ), which along the beam path (e 102 ) on the first mirror ( 110 ) meets; a second construction axis (e ₁ ) along the beam path of the first mirror (e) 110 ) at a point of impact on the second mirror ( 120 ) meets; the second mirror ( 120 ) having a concave mirror surface whose magnitude of the radius of curvature is between 2 and 20 times the minimum system focal length and the magnitude of which is a lateral displacement (d2) of its optical axis (FIG. 122 ) from the point of impact of the second construction axis (e ₁ ) on the second mirror ( 120 ), measured orthogonal to the optical axis ( 122 ) of the second mirror ( 120 ), is less than 2 times the minimum system focal length, the length of the second construction axis (e ₁ ) between the first mirror ( 110 ) and the second mirror ( 120 ) is between 1 and 10 times the minimum system focal length, and a third design axis (e ₃ ) that is along the beam path (FIG. 102 ) of the second mirror ( 120 ) on the third mirror ( 130 ), wherein the length of the third construction axis (e ₂ ) between the second mirror ( 120 ) and the third mirror ( 130 ) is between 0.5 times and 6 times the minimum system focal length; a fourth construction axis (e ₃ ), which along the beam path ( 102 ) of the third mirror ( 130 ) at a point of impact on the fourth mirror ( 140 ) meets; the fourth mirror ( 140 ) having a concave mirror surface whose magnitude of the radius of curvature is between 1 and 15 times the minimum system focal length and whose conical constant is greater than or equal to zero, the length of the fourth axis of construction (e ₃ ) between the third mirror ( 130 ) and the fourth mirror ( 140 ) is between 0.5 times and 6 times the minimum system focal length; and a fifth construction axis (e ₄ ), which along the beam path ( 102 ) of the fourth mirror ( 140 ) meets the image plane, the length of the fifth construction axis (e ₄ ) between the fourth mirror ( 140 ) and the image plane ( 160 ) is between 0.5 times and 10 times the minimum system focal length. Central shading-free mirror objective ( 1600 ) with a variable field of view according to one of claims 1 to 6, having the following further features: the first mirror ( 110 ), which has a plane or concave mirror surface whose amount of the radius of curvature is greater than 0.9 times the minimum focal length of the system and whose conical constant is greater than or equal to zero; a first construction axis (e ₀ ), which along the beam path (e 102 ) on the first mirror ( 110 ) meets; a second construction axis (e ₁ ) along the beam path ( 102 ) from the first mirror ( 110 ) at a point of impact on the second mirror ( 120 ) meets; the second mirror ( 120 ) having a convex mirror surface whose magnitude of the radius of curvature is between 2 and 20 times the minimum system focal length and the magnitude of which is a lateral displacement (d ₂ ) of its optical axis (FIG. 122 ) from the point of impact of the second construction axis (e ₁ ) on the second mirror ( 120 ), measured orthogonal to the optical axis ( 122 ) of the second mirror ( 120 ), is less than 2 times the minimum system focal length, the length of the second construction axis (e ₁ ) between the first mirror ( 110 ) and the second mirror ( 120 ) is between 1 and 10 times the minimum system focal length, and a third construction axis (e ₂ ) which is along the beam path (FIG. 102 ) of the second mirror ( 120 ) on the third mirror ( 130 ), wherein the length of the third construction axis (e ₂ ) between the second mirror ( 120 ) and the third mirror ( 130 ) is between 0.5 times and 6 times the minimum system focal length; a fourth construction axis (e ₃ ), which along the beam path ( 102 ) of the third mirror ( 130 ) at a point of impact on the fourth mirror ( 140 ) meets; the fourth mirror ( 140 ) having a concave mirror surface whose magnitude of the radius of curvature is between 1 and 15 times the minimum system focal length and whose conical constant is greater than or equal to zero, the length of the fourth axis of construction (e ₃ ) between the third mirror ( 130 ) and the fourth mirror ( 140 ) is between 0.5 times and 6 times the minimum system focal length; and a fifth construction axis (e ₄ ), which along the beam path ( 102 ) of the fourth mirror ( 140 ) on the image plane ( 160 ), wherein the length of the fifth construction axis (e ₄ ) between the fourth mirror ( 140 ) and the image plane ( 160 ) is between 0.5 times and 10 times the minimum system focal length. A central shading-free mirror lens with a variable field of view according to one of claims 1 to 6, wherein the fourth mirror ( 140 ) has a concave curvature for all deformation states. A central shadowing mirror with a variable field of view according to any one of claims 1 to 9, wherein the third mirror ( 130 ) is functionally designed as an aperture stop. A central shading-free mirror lens with a variable field of view according to one of claims 1 to 10, in which the deformation of the first mirror ( 110 ) and the deformation of the fourth mirror ( 140 ) by a change in the radius of curvature, the conical constant or higher orders. A central shading-free mirror lens with a variable field of view according to any one of claims 1 to 11, having a variable aperture aperture diaphragm, which is in the beam path in front of the third mirror ( 130 ) is arranged. A central shading-free mirror mirror with a variable field of view according to one of claims 1 to 12, wherein the fourth mirror ( 140 ) is adapted to allow by changing the curvature of its mirror surface focusing. Central shading-free mirror lens with a variable angle of view according to a of claims 1 to 13, where the mirror surfaces of the first to fourth mirrors a metallic layer, a dielectric layer, a dielectric layer stack or a combination of a metallic and have a dielectric layer. Central shading-free mirror lens with a variable angle of view according to a of claims 1 to 14, in which the spectral reflectivity of a mirror surface to a Wavelength range is adjusted. Central shading-free mirror lens with a variable angle of view according to a of claims 1 17, in which a deformable mirror has a sensor, which is adapted to the deformation state of the deformable Mirror to detect. Central shading-free mirror lens with a variable angle of view according to a of claims 1 to 16, which has a diaphragm arranged to be stray light to reduce. A central shading-free mirror lens with a variable angle of view according to one of claims 1 to 17, which has a further optical functional element, which in front of the first mirror ( 110 ) or after the fourth mirror ( 140 ) is arranged. Zentralabschattungsfreie mirror lens with a variable angle of view according to one of claims 1 to 18, which has a further plano-optical functional element in the beam path ( 102 ) between the first mirror ( 110 ) and the fourth mirror ( 140 ) is arranged. Central shading-free mirror lens with a variable angle of view according to claim 19, in which the further plane optical functional element is a mirror, a window, a filter, an element for influencing the polarization of electromagnetic radiation or a prismatic body. Imaging system ( 2300 ; 2400 ; 2500 ) comprising: a central shading-free mirror lens having a variable field of view according to one of claims 1 to 20; a sensor or detector for detecting electromagnetic radiation with at least one element; and a readout electronics for the sensor or detector. Imaging system ( 2300 ) according to claim 21, comprising a spectrally selective beam splitter ( 2370 ), wherein the beam splitter after the fourth mirror ( 140 ) and in front of the sensor or detector. Imaging system ( 2300 ) according to claim 22, which is after the beam splitter ( 2370 ) at least two detectors ( 2361 . 2362 ) for detecting electromagnetic radiation, wherein the detectors are designed for the detection of electromagnetic radiation of different wavelength ranges. Imaging system ( 2400 ) according to claim 21, which is a cover glass ( 250 ), wherein the cover glass ( 250 ) and the third mirror ( 130 ) as a common optical component ( 2480 ) are formed. Image recording system according to one of claims 21 to 24, which has an autofocus sensor. spatially resolving Spectrometer with the following features: a central shading free Mirror lens with a variable angle of view according to a of claims 1 until 20; an element for modulation or filtering of electromagnetic radiation; and a detector for electromagnetic Radiation with at least one element for image acquisition. A method of operating a central shading-free mirror objective according to one of claims 1 to 20, comprising the following step: deformation of the mirror surface of the first mirror ( 110 ) combined with a deformation of the mirror surface of the fourth mirror ( 140 ) to change the angle of view of the lens while keeping the position of the image plane ( 160 ) of the central shading-free mirror lens in the range of the depth of field unchanged. Method for operating a central shading-free Mirror lens according to claim 27 with the following further steps: Recording a picture through an image sensor; and Correction of an image defect of Illustration by editing the picture with Help of a computer program.