CN101685170B - Electrowetting type hybrid refractive-diffractive zooming liquid lens - Google Patents

Abstract

The invention solves the technical problems that an ordinary liquid lens does not have design freedom degree and aberration optimization can not be carried out on a single liquid lens in the background art. The invention relates to an electrowetting type hybrid refractive-diffractive zooming liquid lens which comprises a baseplate framework, a first baseplate and a second baseplate, wherein the peripheries of the first baseplate and the second baseplate are hermetically connected with the baseplate framework 228, an electrolyte and an insulating liquid which are mutually insoluble are filled in a seal cavity formed by the baseplate framework, the first baseplate and the second baseplate, a first annular electrode and a second annular electrode are arranged at the inner side of the baseplate framework, the surface of the second electrode and the inner surface of the baseplate framework are both coated with a hydrophobic insulating layer, and the first electrode is entirely immerged into the electrolyte. The first baseplate or the second baseplate is a diffraction surface baseplate, and the other one is a planar baseplate, or both the first baseplate and the second baseplate are diffraction surface baseplates. The invention provides the design freedom degree of aberrational correction for the liquid lens under the condition of not increasing the weight and the size of the liquid lens or influencing the structure and stability of the liquid lens.

Description

Electrowetting type hybrid refractive-diffractive zooming liquid lens

Technical field

The present invention relates to a kind of liquid Zoom lens, be specifically related to a kind of Electrowetting type hybrid refractive-diffractive zooming liquid lens.

Background technology

The liquid Zoom lens is a kind of novel optical element according to the bionics principle proposition in the world, mainly contain and utilize Zoom lens that electric wetting fluid contact angle changes and based on the Zoom lens of filling liquid surface curvature change, characteristics such as they have wide tunable range, zoom capabilities is strong, zoom is level and smooth, with low cost, handling ease have good application prospects.

The common liq lens, it no matter is the Zoom lens that the Zoom lens that utilizes electric wetting fluid contact angle to change also is based on the filling liquid surface curvature change, according to aberration equations, required focal power is in case determine, interfacial curvature is just determined thereupon between the surface curvature of lens or two kinds of non soluble liquids.Therefore, under the situation that required focal power is determined, an independent liquid lens itself does not have the degree of freedom of aberration correction, and this makes that lens can not blur-free imaging in imaging process.When liquid lens is applied to the design of zoom system, pancreatic system, because liquid lens itself can not aberration correction, if require system's blur-free imaging, can make system complex, the eyeglass number increases, and is unfavorable for microminiaturization, the dexterityization of zoom system, pancreatic system.

Referring to figure, existing common electrical moist type liquid lens mainly is made of the first substrate glasses plate 121, the second substrate glasses plate 122, first metal electrode 123, second metal electrode 124, hydrophobic nature insulation course 125, electrolytic liquid 126 and iknsulating liquid 127.When between first metal electrode 123 and second metal electrode 124, adding appropriate voltage, owing to the contact angle between two kinds of immiscible liquid electrolyte liquid 126 and iknsulating liquid 127 and the hydrophobic nature insulation course 125 changes, make the interfacial curvature radius R of 127 of electrolytic liquid 126 and iknsulating liquids change, cause that the focal distance f of Electrowetting type liquid lens changes.Corresponding-definite focal power Φ, because two outside surfaces, the first substrate glasses plate 121 and the second substrate glasses plate 122 of Electrowetting type liquid lens all are the planes, then the radius of curvature R at electrolytic liquid 126 and 127 interfaces of iknsulating liquid must be determined, could realize required focal power Φ like this, therefore in optical design, be not used in the degree of freedom of optimizing picture element.

In recent years, for the research of this class component focus mostly on image-forming principle checking and lens arrangement and stable aspect, do not see the research report for the raising of lens imaging quality as yet with improving.

At present, Vairoptic company, Philip company, Samsung, company limited of Lucent Technologies etc. are very fast to the design studies technical progress of liquid lens, mainly comprise the Electrowetting type liquid lens such as electrode form, version, filling liquid of electric wetting liquid lens.But, as single varifocal element, how to proofread and correct liquid lens aberration, improve the lens imaging quality, make that the technical research aspect the acquisition photo-quality imaging quality does not see that so far report is arranged under the situation of weight and volume minimum.Domestic Shanghai University of Science and Technology, Tsing-Hua University etc. have also carried out the research of liquid lens aspect in recent years, but all are at the imaging mechanism of liquid lens and the research of manufacture craft aspect mostly, also do not see about improving the report of single liquid lens image quality.

Summary of the invention

The object of the present invention is to provide a kind of Electrowetting type hybrid refractive-diffractive zooming liquid lens, it has solved, and the common liq lens do not have design freedom in the background technology, can't carry out the technical matters that aberration is optimized on the monolithic liquid lens.

Design proposal of the present invention is as follows:

A kind of Electrowetting type hybrid refractive-diffractive zooming liquid lens, comprise base panel frame 228, also comprise first substrate 222 and second substrate 221 that periphery and base panel frame 228 are tightly connected, be filled with immiscible electrolytic solution 226 and dielectric 227 in the annular seal space 229 that the described base panel frame 228 and first substrate 222 and second substrate 221 constitute, the inboard of described base panel frame 228 is provided with first electrode 223 and second electrode 224 of annular, the inside surface of the surface of described second electrode 224 and base panel frame 228 is coated with hydrophobic insulation course 225 entirely, and described first electrode 223 is immersed in the electrolytic solution 226 fully; Its special character is: one of described first substrate 222 and second substrate 221 are the diffraction surfaces substrate, another be planar substrates.

Above-described diffraction surfaces substrate is that glass is from material substrate or optical plastic substrate etc.

A kind of Electrowetting type hybrid refractive-diffractive zooming liquid lens, comprise base panel frame 228, also comprise first substrate 222 and second substrate 221 that periphery and base panel frame 228 are tightly connected, be filled with immiscible electrolytic solution 226 and dielectric 227 in the annular seal space 229 that the described base panel frame 228 and first substrate 222 and second substrate 221 constitute, the inboard of described base panel frame 228 is provided with first electrode 223 and second electrode 224 of annular, the inside surface of the surface of described second electrode 224 and base panel frame 228 is coated with hydrophobic insulation course 225 entirely, and described first electrode 223 is immersed in the electrolytic solution 226 fully; Its special character is: described first substrate 222 and second substrate 221 are the diffraction surfaces substrate.

Above-described diffraction surfaces substrate is glass material substrate or optical plastic substrate etc.

The present invention has following advantage:

1. increase the design freedom of liquid lens, made the monolithic liquid lens can realize apochromatism, spherical aberration.

The present invention with the planar substrates of liquid lens directly as the diffraction optics face, at weight that does not increase liquid lens and volume, do not influence under the condition of liquid lens structure and stability and provide the design freedom of aberration correction for liquid lens, according to different imagings and zoom requirement, can the different diffraction surfaces parameter of appropriate design, as required liquid lens is carried out the picture element optimal design, improve the image quality of single liquid lens.

3. the present invention directly is integrated in the liquid lens substrate with diffraction optical element, and liquid lens can be applied in the design of miniature, dexterityization zoom system, have good imaging quality, volume little, in light weight, make characteristics simple, that be easy to control.

4. adopt the present invention can make varifocal optical system have littler volume and weight, make simple a slice or the two foldings hybrid liquid lens that spreads out that adopts realize that the zoom system, pancreatic system that improves imaging becomes possibility.

5. can expand to more widely and various image quality is had higher requirements, again system dimension be had in the system of strict demand simultaneously, can guarantee the microminiaturization of system.

Description of drawings

Fig. 1 is the structural representation of existing common electrical moist type liquid lens.

Fig. 2 mixes the system architecture synoptic diagram of Electrowetting type liquid lens for the present invention's folding spreads out.

Fig. 3 is the modulation transfer function (MTF) curve synoptic diagram of existing common electrical moist type liquid lens under short focal length.

Fig. 4.For spreading out, the present invention's folding mixes the modulation transfer function (MTF) curve synoptic diagram of Electrowetting type liquid lens under short focal length.

Fig. 5 is the existing modulation transfer function (MTF) curve synoptic diagram of common electrical moist type liquid lens under long-focus

Fig. 6 mixes the modulation transfer function (MTF) curve synoptic diagram of Electrowetting type liquid lens under long-focus for the present invention's folding spreads out.

Accompanying drawing drawing explanation: the 121-first substrate glasses plate, the 122-second substrate glasses plate, 123-first metal electrode, 124-second metal electrode, 125-hydrophobic nature insulation course, 126-electrolytic liquid, 127-iknsulating liquid; 221-second substrate, 222-first substrate, 223-first electrode, 224-second electrode, 225-hydrophobic insulation course, 226-electrolytic solution, 227-dielectric, 228-base panel frame, 229-annular seal space.

Embodiment

The present invention will have common plane substrate of glass in the common liq lens now, and to be designed to diffraction optical element be the diffraction surfaces substrate, this diffraction surfaces substrate can be the first substrate glasses plate 121 in the existing common electrical moist type liquid lens or the second substrate glasses plate 122 it, the perhaps first substrate glasses plate 121 and the second substrate glasses plate 122.The present invention has added the diffraction optics face by adopting diffraction optical element, has promptly introduced the phase function of binary face:

$\mathrm{\φ}\left(r\right)=\frac{2\mathrm{\π}}{\mathrm{\λ}}(A_1{y}^2+A_2{y}^4+...)$

The introducing of binary phase function, make matching of liquid lens aberration and the number formation become following form:

$S_I=\frac{y^4}{4}\{{{\mathrm{\φ}}_1}^3[{\left(\frac{n_1}{n_1-1}\right)}^2+\frac{n_1+2}{n_1{(n_1-1)}^2}+\frac{4(n_1+1)}{n_1(n_1-1)}{C}_1+\frac{3n_1+2}{n_1}{C_1}^2]$

$+{{\mathrm{\φ}}_2}^3[{\left(\frac{n_2}{n_2-1}\right)}^2+\frac{n_2+2}{n_2{(n_2-1)}^2}+\frac{4(n_2+1)}{n_2(n_2-1)}{C}_2+\frac{3n_2+2}{n_2}{C_2}^2]$

$+{{\mathrm{\&phi;}}_3}^3[(1+3{{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="H2008101511329E00022.png"\; state="\{\{state\}\}">C</figure-callout>}}_3}^2)-32\mathrm{m\&lambda;}{A}_2]\}$

$S_{\mathrm{II}}=-y^{2}H\{\frac{{{\mathrm{\&phi;}}_1}^2}{2}[\frac{{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="H2008101511329E00032.png"\; state="\{\{state\}\}">n</figure-callout>}}_1+1}{n_1(n_1-1)}+\frac{2{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="H2008101511329E00032.png"\; state="\{\{state\}\}">n</figure-callout>}}_1+1}{n_1}{C}_1]+\frac{{{\mathrm{\&phi;}}_2}^2}{2}[-\frac{n_2+1}{n_2(n_2-1)}+\frac{2n_2+1}{n_2}{C}_1]+{\mathrm{\&phi;}}_3{C}_3\}$

S _III＝H ²(φ ₁+φ ₂+φ ₃)＝H ²φ

$S_{\mathrm{IV}}=H^2(\frac{{\mathrm{\&phi;}}_1}{{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="H2008101511329E00032.png"\; state="\{\{state\}\}">n</figure-callout>}}_1}+\frac{{\mathrm{\&phi;}}_2}{n_2})$

S _V＝0

Wherein, S ₁-S _VBe five aberrations and the number of lens, reflect the size of spherical aberration, coma, astigmatism, the curvature of field and distortion respectively.φ ₁, φ ₂It is respectively the focal power of bearing along two kinds of liquid of incident order; φ ₃It is the focal power that the diffraction optics face is born; Y is marginal ray and the lens intersection point distance to optical axis; n ₁, n ₂Be respectively along two kinds of liquid refractive index of incident order; H is the Laplace invariant; C ₁-C ₃Be respectively conjugate factor along two kinds of lens shapes that liquid constitutes of incident order and diffraction surfaces, the aperture angle decision of incident and outgoing when lens shape that constitutes through every kind of liquid by light or diffraction surfaces; M is that the order of diffraction of correspondence is inferior, if do not specialize, and common m=1; λ is a corresponding wavelength; A ₂Be four item coefficients in the binary face phase function, i.e. quadravalence asphericity coefficient.

Add the design of diffraction optics face in liquid lens system after, it matches to such an extent that a quadravalence asphericity coefficient A occurred in aberration and the number ₂This asphericity coefficient makes liquid lens system have a design freedom, thereby makes single liquid lens can realize the aberration optimal design.The quadravalence asphericity coefficient can be used for the spherical aberration correction of liquid lens.Simultaneously because the negative dispersion characteristic of diffraction surfaces also may realize the apochromatism of Electrowetting type liquid lens.

The present invention directly is integrated in the substrate of Electrowetting type liquid lens with diffraction optical element, be about to the primary structure ingredient of diffraction optics face as liquid lens, this method can not change the design freedom that aberration correction is provided for liquid lens under liquid lens weight, size, the stability condition, thereby can carry out the picture element optimal design to liquid lens as required, improve the liquid lens image quality.The invention enables simple employing a slice or the two foldings hybrid liquid lens that spreads out to realize that the zoom system, pancreatic system that improves imaging becomes possibility.According to different imagings and zoom requirement, can the different diffraction surfaces parameter of appropriate design.

Fig. 2 is specially the present invention and adopts the system architecture synoptic diagram of rolling over the mixing Electrowetting type liquid lens that spreads out.The periphery of first substrate 222 and second substrate 221 all is tightly connected the annular seal space 229 of formation with base panel frame 228.Be filled with immiscible electrolytic solution 226 and dielectric 227 in the annular seal space 229.The inboard of base panel frame 228 is provided with first annular electrode 223 and second electrode, 224, the first electrodes 223 and second electrode 224 and is generally metal electrode.The inside surface of the surface of second electrode 224 and base panel frame 228 is coated with hydrophobic insulation course 225 entirely.First electrode 223 is immersed in the electrolytic solution 226 fully.The present invention can be that one of first substrate 222 and second substrate 221 are the diffraction surfaces substrate, another be planar substrates.Also can be that first substrate 222 and second substrate 221 are the diffraction surfaces substrate.The diffraction surfaces substrate is a diffraction optical element, specifically can adopt glass material substrate or other optical material substrate, as: optical plastic etc.

The present invention can be implemented in single Electrowetting type and roll over part aplanasia and apochromatism in the mixing material lens that spread out by the adding of diffraction surfaces substrate, can make this folding spread out and mix the more perfect image of Electrowetting type liquid lens acquisition.

The present invention folding spreads out the contrast of modulation transfer function (MTF) in the focal length variations of mixing material lens and the common liq focal length of lens change procedure referring to Fig. 3,4,5,6.As seen after adding diffraction surfaces, the modulation transfer function (MTF) of system under different focal all obviously improves, and image quality is optimised.

Claims (4)

1. Electrowetting type hybrid refractive-diffractive zooming liquid lens, comprise base panel frame (228), also comprise first substrate (222) and second substrate (221) that periphery and base panel frame (228) are tightly connected, be filled with immiscible electrolytic solution (226) and dielectric (227) in the annular seal space (229) that described base panel frame (228) and first substrate (222) and second substrate (221) constitute, the inboard of described base panel frame (228) is provided with first electrode (223) and second electrode (224) of annular, the inside surface of the surface of described second electrode (224) and base panel frame (228) is coated with hydrophobic insulation course (225) entirely, and described first electrode (223) is immersed in the electrolytic solution (226) fully; It is characterized in that: one of described first substrate (222) and second substrate (221) are the diffraction surfaces substrate, another be planar substrates; The design of described diffraction surfaces substrate make matching of this liquid lens aberration and number constitute following form:

$S_I=\frac{y^4}{4}\left\{{{\mathrm{\&phi;}}_1}^3\right[{\left(\frac{n_1}{n_1-1}\right)}^2+\frac{n_1+2}{n_1{(n_1-1)}^2}+\frac{4(n_1+1)}{n_1(n_1-1)}{C}_1+\frac{3n_1+2}{n_1}{C_1}^2]$

$+{{\mathrm{\&phi;}}_2}^3[{\left(\frac{n_2}{n_2-1}\right)}^2+\frac{n_2+2}{n_2{(n_2-1)}^2}+\frac{4(n_2+1)}{n_2(n_2-1)}{C}_2+\frac{3n_2+2}{n_2}{C_2}^2]$

$+{{\mathrm{\&phi;}}_3}^3[(1+3{C_3}^2)-32\mathrm{m\&lambda;}{A}_2]\}$

$S_{\mathrm{II}}=-y^{2}H\left\{\frac{{{\mathrm{\&phi;}}_1}^2}{2}\right[\frac{n_1+1}{n_1(n_1-1)}+\frac{2n_1+1}{n_1}{C}_1]+\frac{{{\mathrm{\&phi;}}_2}^2}{2}[-\frac{n_2+1}{n_2(n_2-1)}+\frac{2n_2+1}{n_2}{C}_2]+{\mathrm{\&phi;}}_3{C}_3\}$

S _III＝H ²(φ ₁+φ ₂+φ ₃)＝H ²φ

$S_{\mathrm{IV}}=H^2(\frac{{\mathrm{\&phi;}}_1}{n_1}+\frac{{\mathrm{\&phi;}}_2}{n_2})$

S _V＝0

Wherein, S _I-S _VBe five aberrations and the number of this liquid lens, reflect the size of spherical aberration, coma, astigmatism, the curvature of field and distortion respectively; φ ₁, φ ₂It is respectively the focal power of bearing along two kinds of liquid of incident order; φ ₃It is the focal power that the diffraction optics face is born; Y is marginal ray and the lens intersection point distance to optical axis; n ₁, n ₂Be respectively along two kinds of liquid refractive index of incident order; H is the Laplace invariant; C ₁-C ₃Be respectively the conjugate factor that constitutes lens shape and diffraction surfaces along incident order electrolytic solution (226), dielectric (227), the aperture angle decision of incident and outgoing when lens shape that constitutes through every kind of liquid by light or diffraction surfaces; M is that the order of diffraction of correspondence is inferior; λ is a corresponding wavelength; A ₂Be four item coefficients in the binary face phase function, i.e. quadravalence asphericity coefficient.

2. Electrowetting type hybrid refractive-diffractive zooming liquid lens according to claim 1 is characterized in that: described diffraction surfaces substrate is glass material substrate or optical plastic substrate.

3. Electrowetting type hybrid refractive-diffractive zooming liquid lens, comprise base panel frame (228), also comprise first substrate (222) and second substrate (221) that periphery and base panel frame (228) are tightly connected, be filled with immiscible electrolytic solution (226) and dielectric (227) in the annular seal space (229) that described base panel frame (228) and first substrate (222) and second substrate (221) constitute, the inboard of described base panel frame (228) is provided with first electrode (223) and second electrode (224) of annular, the inside surface of the surface of described second electrode (224) and base panel frame (228) is coated with hydrophobic insulation course (225) entirely, and described first electrode (223) is immersed in the electrolytic solution (226) fully; It is characterized in that: described first substrate (222) is the diffraction surfaces substrate with second substrate (221); The design of described diffraction surfaces substrate make matching of this liquid lens aberration and number constitute following form:

$S_I=\frac{y^4}{4}\left\{{{\mathrm{\&phi;}}_1}^3\right[{\left(\frac{n_1}{n_1-1}\right)}^2+\frac{n_1+2}{n_1{(n_1-1)}^2}+\frac{4(n_1+1)}{n_1(n_1-1)}{C}_1+\frac{3n_1+2}{n_1}{C_1}^2]$

$+{{\mathrm{\&phi;}}_2}^3[{\left(\frac{n_2}{n_2-1}\right)}^2+\frac{n_2+2}{n_2{(n_2-1)}^2}+\frac{4(n_2+1)}{n_2(n_2-1)}{C}_2+\frac{3n_2+2}{n_2}{C_2}^2]$

$+{{\mathrm{\&phi;}}_3}^3[(1+3{C_3}^2)-32\mathrm{m\&lambda;}{A}_{23}]+{{\mathrm{\&phi;}}_4}^3[(1+3{C_4}^2)-32\mathrm{m\&lambda;}{A}_{24}]\}$

$S_{\mathrm{II}}=-y^{2}H\left\{\frac{{{\mathrm{\&phi;}}_1}^2}{2}\right[\frac{n_1+1}{n_1(n_1-1)}+\frac{2n_1+1}{n_1}{C}_1]+\frac{{{\mathrm{\&phi;}}_2}^2}{2}[-\frac{n_2+1}{n_2(n_2-1)}+\frac{2n_2+1}{n_2}{C}_2]+{\mathrm{\&phi;}}_3{C}_3+{\mathrm{\&phi;}}_4{C}_4\}$

S _III＝H ²(φ ₁+φ ₂+φ ₃+φ ₄)＝H ²φ

$S_{\mathrm{IV}}=H^2(\frac{{\mathrm{\&phi;}}_1}{n_1}+\frac{{\mathrm{\&phi;}}_2}{n_2})$

S _V＝0

Wherein, S _I-S _VBe five aberrations and the number of this liquid lens, reflect the size of spherical aberration, coma, astigmatism, the curvature of field and distortion respectively; φ ₁, φ ₂It is respectively the focal power of bearing along two kinds of liquid of incident order; φ ₃, φ ₄It is respectively the focal power that the first substrate diffraction optics face and the second substrate diffraction optics face are born; Y is marginal ray and the lens intersection point distance to optical axis; n ₁, n ₂Be respectively along two kinds of liquid refractive index of incident order; H is the Laplace invariant; C ₁-C ₄Be respectively conjugate factor along two kinds of lens shapes that liquid constitutes of incident order and the first substrate diffraction surfaces, the second substrate diffraction surfaces, the aperture angle decision of incident and outgoing when lens shape that constitutes through every kind of liquid by light or diffraction surfaces; M is that the order of diffraction of correspondence is inferior; λ is a corresponding wavelength; A ₂₃, A ₂₄Be respectively four item coefficients in the phase function of the first substrate diffraction optics face and the second substrate diffraction optics face, i.e. quadravalence asphericity coefficient.

4. Electrowetting type hybrid refractive-diffractive zooming liquid lens according to claim 3 is characterized in that: described diffraction surfaces substrate is glass material substrate or optical plastic substrate.

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