CN202600322U - Zoom lens and imaging device - Google Patents

Abstract

The utility model relates to the technical field of optical elements, and provides a zoom lens and an imaging device comprising the zoom lens. The zoom lens comprises a first electrode, a second electrode and an electric control doubly refracting crystal layer, wherein the first electrode and the second electrode are respectively arranged on both sides of the electric control doubly refracting crystal layer, and the ray passing through the zoom lens is refracted by the electric control doubly refracting crystal layer under the action of an electric field formed between the first electrode and the second electrode. By adopting the utility model, the refractive index distribution of a material is changed by utilizing once electro-optic effect (Pockels electro-optical effect) of a crystal material, so that a focusing function of the lens is realized. The zoom lens has the advantages of high light transmittance, quick response speed and wide application range.

Description

Zoom lens and imaging device

Technical field

The utility model relates to the optical element technology field, relates in particular to a kind of zoom lens and imaging device.

Background technology

Generally the focal length that changes camera lens through the relative position that changes a plurality of eyeglasses that comprise in the camera lens in the existing imaging device; This zoom mode is called optical zoom; Optical zoom can obtain high-quality image, is applied to high-quality imaging system more, for example camera lens of single-lens reflex camera etc.; But this mode is to accomplish the focusing process through the relative distance between each eyeglass in the mechanical adjustment camera lens, is not suitable for that imaging device is lightening, the developing direction of miniaturization.

In order to adapt to the lightening developing direction with miniaturization of imaging device, proposed a kind ofly again through changing the size of lens imaging face, promptly the diagonal line length of imaging surface changes the focusing mode of lens focus; This zoom mode is called Digital Zoom; Because it uses single eyeglass, be used in the lightening digital photography, for example the camera lens in the mobile phone etc. more; Though this mode can realize certain focusing function, but be cost with the loss quality of image.

Along with science and technology development; Occurred liquid lens again, liquid lens is to utilize electric wetting principle, comes controlling liquid shape and change of refractive through electric field; Thereby realization zoom; This zoom lens are called liquid lens, because the structure more complicated of liquid lens, therefore control is got up also relatively difficult.

In sum, focusing mode of the prior art has following defective:

1, the complex manufacturing of optical focusing mode, higher, the complex operation step of production cost need the professional to operate, and be unfavorable in ordinary populace, applying, and manually-operated also can cause and camera lens shake causes image blur;

2, the Digital Zoom mode can be lost the quality of image, and imaging effect is relatively poor;

3, the complex structure of liquid lens, the control difficulty.

The utility model content

The technical matters that (one) will solve

The technical matters that the utility model will solve is, to above-mentioned defective, how a kind of zoom lens and imaging device of focusing can realized is provided, and it is simple in structure, production cost is low.

(2) technical scheme

For solving the problems of the technologies described above; The utility model provides a kind of zoom lens; Comprise: first electrode, second electrode and electrically conerolled birefringence crystal layer; Wherein said first electrode and said second electrode are arranged at the both sides of said electrically conerolled birefringence layer respectively, and under the effect of electric field that forms between said first electrode and said second electrode, said electrically conerolled birefringence crystal layer reflects the light through said zoom lens.

Preferably, the width of said first electrode is less than the width of said second electrode.

Wherein, the direction of an electric field that forms between the incident direction of said light through zoom lens and said first electrode and second electrode is parallel.

Wherein, said first electrode and said second electrode are transparency electrode.

Wherein, said electrically conerolled birefringence crystal layer is processed by the potassium dihydrogen phosphate crystal material.

Wherein, said electrically conerolled birefringence crystal layer thickness everywhere is identical.

Wherein, said electrically conerolled birefringence crystal layer is lens-shaped.

Wherein, the direction of an electric field that forms between the incident direction of said light through zoom lens and said first electrode and second electrode is vertical.

Wherein, said electrically conerolled birefringence crystal layer is processed by the lithium columbate crystal material.

Wherein, said electrically conerolled birefringence crystal layer thickness everywhere is identical.

The utility model also provides a kind of imaging device, comprises above-mentioned each zoom lens.

(3) beneficial effect

The utility model discloses a kind of zoom lens and comprise the imaging device of said zoom lens, utilize an electrooptical effect (bubble Ke Ersi electrooptical effect) of crystalline material to change the index distribution of material, thereby realize the lens focusing function.This lens light transmitance is high, and response speed is fast, and is applied widely.

Description of drawings

Fig. 1 is the structural representation of the utility model embodiment 1 described zoom lens;

Fig. 2 is the structural representation of the utility model embodiment 2 described zoom lens;

Fig. 3 is the structural representation of the utility model embodiment 3 described zoom lens.

Wherein, 10: the first electrodes; 20: the electrically conerolled birefringence crystal layer; 30: the second electrodes.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the embodiment of the utility model is done further explain.Following examples are used to explain the utility model, but are not used for limiting the scope of the utility model.

The electric birefringence crystal outside under the effect of electric field refractive index can change, this phenomenon is called electrooptical effect.Electrooptical effect comprises bubble Ke Ersi (Pockels) effect and Ke Er (Kerr) effect, in the utility model to have material that electrooptical effect promptly steeps the Ke Ersi effect as embodiment.

Usually can the change of refractive that the electric birefringence crystal causes under the effect of electric field outside be represented with following formula:

n＝n ₀+aE+bE ²+......(1)

Wherein a, b are constant, n ₀Refractive index when being E=0.The effect of the variations in refractive index that is caused by aE once is called electrooptical effect or electrooptical effect, also claims bubble Ke Ersi (Pockels) effect.An electrooptical effect only is present in eicosanoid not to be had in the crystal at symmetrical center.By quadratic term bE ²The effect of the variations in refractive index that causes is called quadratic electro-optical effect and also claims quadratic electro-optic effect or Ke Er (Kerr) effect, and quadratic electro-optical effect then possibly be present in any material, and the electrooptical effect of liquid crystal belongs to quadratic electro-optical effect.A general electrooptical effect is significant more than quadratic electro-optical effect.

Electrooptical effect is analyzed with the variation of index ellipsoid usually, and the index ellipsoid equation of crystal when added electric field not is:

$\frac{x^2}{n_x^2}+\frac{y^2}{n_y^2}+\frac{z^2}{n_z^2}=1---\left(2\right)$

N in the formula _x, n _y, n _zBe respectively crystal along three main shaft x, y, the last principal refractive index of z.Crystal index ellipsoid under the extra electric field effect changes, and promptly three of ellipsoid main spindle's and length all change, and the size and Orientation of the size of variation and extra electric field E and the character of crystal are relevant.

After crystal applied electric field, its index ellipsoid equation became:

${\left(\frac{1}{n^2}\right)}_1{x}^2+{\left(\frac{1}{n^2}\right)}_2{y}^2+{\left(\frac{1}{n^2}\right)}_3{z}^2+2{\left(\frac{1}{n^2}\right)}_4\mathrm{yz}+2{\left(\frac{1}{n^2}\right)}_5\mathrm{xz}+2{\left(\frac{1}{n^2}\right)}_6\mathrm{xz}=1---\left(3\right)$

Since external electric field, each coefficient (1/n of index ellipsoid ²) linear change takes place thereupon, its variable quantity may be defined as

$\mathrm{\Δ}{\left(\frac{1}{n^2}\right)}_i=\underset{j=1}{\overset{3}{\mathrm{\Σ}}}{\mathrm{\γ}}_{\mathrm{ij}}{E}_j---\left(4\right)$

γ in the formula _IjBe called linear electro-optic coefficient; I value 1 ..., 6; J value 1,2,3.

An electrooptical effect of electric birefringence crystal is divided into longitudinal electro-optic effect and cross electro-optical effect.Longitudinal electro-optic effect is to be added in the electrooptical effect that direction of an electric field on the electric birefringence crystal produces when parallel with the direction of propagation of light in the electric birefringence crystal; Cross electro-optical effect is to be added in the electrooptical effect that direction of an electric field on the electric birefringence crystal produces when vertical with the direction of propagation of light in the electric birefringence crystal; Observe longitudinal electro-optic effect potassium dihydrogen phosphate (KDP) crystal commonly used and carry out, and lithium niobate (LiNbO ₃) crystal then is used to produce cross electro-optical effect.

During as electrically conerolled birefringence crystalline material of the present invention, on the basis based on above-mentioned formula (1), (2), (3) and (4), n is arranged with the potassium dihydrogen phosphate crystal in the tetragonal crystal system among one of them embodiment of the present invention _x=n _y=n _o, n _z=n _e, n _o＞n _e, have only γ ₄₁, γ ₅₂, γ ₆₃≠ 0, and γ ₄₁=γ ₅₂

Obtain crystal and add new index ellipsoid equation behind the external electric field E

$\frac{x^2}{n_o^2}+\frac{y^2}{n_o^2}+\frac{z^2}{n_e^2}+{2r}_{41}{\mathrm{yzE}}_x+2r_{41}{\mathrm{xzE}}_y+{2r}_{63}{\mathrm{xyE}}_z=1---\left(5\right)$

Be KDP crystal when in longitudinal electric field, using, make the direction of extra electric field be parallel to z axle, E _z=E, E _x=E _y=0, so have

$\frac{x^2}{n_o^2}+\frac{y^2}{n_o^2}+\frac{z^2}{n_e^2}+{2r}_{63}{\mathrm{xyE}}_z=1---\left(6\right)$

X coordinate and y coordinate are obtained responding to main shaft coordinate system (x ', y ', z ') around z axle rotation alpha angle, when α=45 °, ground ellipsoid equation does in the main shaft coordinate system

$(\frac{1}{n_o^2}+r_{63}{E}_z)x^{\′2}+(\frac{1}{n_o^2}-r_{63}{E}_z){\mathrm{ay}}^{\′2}+\frac{1}{n_e^2}{z}^{\′2}=1---\left(7\right)$

Principal refractive index becomes

$\left.\begin{array}{c}{n}_{x^{\′}}=n_o+\frac{1}{2}{n}_o^3{r}_{63}{E}_z\\ n_{y^{\′}}=n_o-\frac{1}{2}{n}_o^3{r}_{63}{E}_z\\ n_{z^{\′}}=n_e\\ \end{array}\right\}---\left(8\right)$

The KDP crystal is during along z axle added electric field; Become biaxial crystal by uniaxial crystal, the main shaft of index ellipsoid has rotated 45 around the z axle, and the size of this corner and extra electric field is irrelevant; Its variations in refractive index is directly proportional with electric field, and this is to utilize electrooptical effect to realize the physical basis of light modulation techniques.

In the longitudinal electric field of KDP was used, along crystal z axle added electric field, light wave was propagated along the z direction, the birefringent characteristic of crystal layer depend on ellipsoid with perpendicular to the formed ellipse of the Plane intersects of z axle.Make z '=0 in (7) formula, obtain this oval equation and do

$(\frac{1}{n_o^2}+r_{63}{E}_z)x^{\′2}+(\frac{1}{n_o^2}-r_{63}{E}_z)y^{\′2}=1---\left(9\right)$

Long and short semiaxis overlaps with x ' and y ' respectively, and x ' and y ' be the polarization direction of two components just, and corresponding refractive index is n _{X '}And n _{Y '},

$n_{x^{\′}}=n_o+\frac{1}{2}{n}_o^3{r}_{63}{E}_z$ (10)

$n_{y^{\′}}=n_o-\frac{1}{2}{n}_o^3{r}_{63}{E}_z$

, these two light waves will produce a refringence after passing crystal,

$\mathrm{\Δn}=n_{x^{\′}}-n_{y^{\′}}=n_o^3{r}_{63}{E}_z---\left(11\right)$

This Δ n is caused that by the birefringence that electrooptical effect causes the distribution of electric field has also just determined the distribution of refractive index, thereby realizes the lens zoom.E in the formula _zFor electric field intensity z to component.

Among the another one embodiment of the present invention, be example with the horizontal utilization of lithium columbate crystal in the trigonal system, lithium columbate crystal is a uniaxial negative crystal, i.e. n _x=n _y=n ₀, n _z=n _eTrigonal system 3m point group electrooptical coefficient under it has four, i.e. γ ₂₂, γ ₁₃, γ ₃₃, γ ₅₁Can get the index ellipsoid equation of lithium columbate crystal behind extra electric field thus is:

$(\frac{1}{n_0^2}-{\mathrm{\γ}}_{22}{E}_y+{\mathrm{\γ}}_{15}{E}_z)x^2+(\frac{1}{n_0^2}+{\mathrm{\γ}}_{22}{E}_y+{\mathrm{\γ}}_{13}{E}_z)y^2$ (12)

$+(\frac{1}{n_e^1}+{\mathrm{\γ}}_{33}{E}_z)z^2+{2\mathrm{\γ}}_{51}(E_z\mathrm{yz}+E_x\mathrm{xz})-{2\mathrm{\γ}}_{22}{E}_x\mathrm{xy}=1$

Lithium columbate crystal adopts 45 °-z cutting, along x axle or the pressurization of y axle, and the operational mode of the logical light of z direction of principal axis, when on the main shaft x direction of principal axis during extra electric field, promptly transverse electric field has E _z=E _y=0, crystal main shaft x, y will rotate, and (5) formula becomes:

$\frac{x^2}{n_o^2}+\frac{y^2}{n_o^2}+\frac{z^2}{n_e^2}+{2r}_{51}\mathrm{xz}{E}_z-2r_{22}{\mathrm{xyE}}_z=1---\left(13\right)$

Because of γ ₅₁E _x＜＜1, so respective items can be ignored, through coordinate transform, the principal refractive index that can obtain on three induction main shaft x ', y ', the z ' (still on the z direction) becomes shown in (14) formula.

Wherein lithium columbate crystal becomes biaxial crystal, and the direction and the thickness of its index ellipsoid z axle remain unchanged basically, and x, the y cross section is n by radius ₀Become ellipse, the oval original relatively x y axle of major and minor axis direction x ' y ' has rotated 45 °, and the size of corner and the size of extra electric field are irrelevant, and oval length n _x, n _ySize and extra electric field Ex linear.

$\left.\begin{array}{c}{n}_{x^{\′}}=n_o+\frac{1}{2}{n}_o^3{r}_{22}{E}_x\\ n_{y^{\′}}=n_o-\frac{1}{2}{n}_o^3{r}_{22}{E}_x\\ n_{z^{\′}}=n_e\\ \end{array}\right\}---\left(14\right)$

When light when lithium columbate crystal optical axis z direction is propagated, through behind the crystal, because the cross electro-optical effect (x-z) of crystal, two orthogonal polarization components will produce phase differential:

$\mathrm{\Δn}=n_{x^{\′}}-n_{y^{\′}}=n_o^3{r}_{22}{E}_x---\left(15\right)$

E in the formula _zFor electric field intensity x to component.

Then, can realize the change of index distribution, and then realize the focusing function of crystalline lens through changing the distribution of electric field intensity in formula (11), (15).

Embodiment 1:

As shown in Figure 1; The described zoom lens of the utility model comprise first electrode, 10, the second electrodes 30; Electrically conerolled birefringence crystal layer 20; Said first electrode 10 and said second electrode 30 are arranged at the both sides of said electrically conerolled birefringence crystal layer 20 respectively, and under the effect of electric field that forms between said first electrode and said second electrode, said electrically conerolled birefringence crystal layer reflects the light through said zoom lens.Along with the variation of electric field intensity, said electrically conerolled birefringence crystal layer also changes to the degree that the light through said zoom lens reflects, thereby has realized the zoom function of said zoom lens.

The direction of an electric field of formation is parallel between the incident direction of said light through zoom lens and said first electrode 10 and second electrode 30.

Said first electrode 10 can be transparency electrode with said second electrode 30, can strengthen the light permeable rate of zoom lens.

Said electrically conerolled birefringence crystal layer 20 is processed by the potassium dihydrogen phosphate crystal material that thickness is identical everywhere.

Preferably; The width of first electrode 10 is less than the width of second electrode 30; Adopt this kind mode, can realize the Gradient distribution of the electric field of electrically conerolled birefringence crystal edge, thereby realize electrically conerolled birefringence crystal 20 each zone is applied different electric fields; Make each regional refractive index different, reach the effect that converges light.

Through changing the voltage of the electric field that forms between first electrode described in the above-mentioned zoom lens and said second electrode, utilize an electrooptical effect (bubble Ke Ersi electrooptical effect) of crystalline material to change the index distribution of material, thereby realize the lens focusing function.

Embodiment 2:

As shown in Figure 2, present embodiment and embodiment 1 are basic identical, and difference only is that said electrically conerolled birefringence layer 20 is the collector lens shape of thick middle thin edge, for example lens-shaped.

Use present embodiment and can save the crystalline material that constitutes said electrically conerolled birefringence layer 20.

Embodiment 3:

As shown in Figure 3; Present embodiment and embodiment 1 are basic identical; Difference only is that the incident direction of said light through zoom lens is vertical with the direction of an electric field of second electrode, 30 formation with said first electrode 10, said electrically conerolled birefringence crystal layer 20 by thickness everywhere identical the lithium columbate crystal material process.

Use the cross electro-optical effect that present embodiment can utilize material.

In addition, the utility model also provides a kind of imaging device that comprises above-mentioned zoom lens.

In sum, the utility model discloses a kind of zoom lens and comprise the imaging device of said zoom lens, utilize an electrooptical effect (bubble Ke Ersi electrooptical effect) of crystalline material to change the index distribution of material, thereby realize the lens focusing function.This lens light transmitance is high, and response speed is fast, and is applied widely.

Above embodiment only is used to explain the utility model; And be not the restriction to the utility model; The those of ordinary skill in relevant technologies field under the situation of spirit that does not break away from the utility model and scope, can also be made various variations and modification; Therefore all technical schemes that are equal to also belong to the category of the utility model, and the scope of patent protection of the utility model should be defined by the claims.

Claims (11)

1. zoom lens; It is characterized in that; Comprise: first electrode, second electrode and electrically conerolled birefringence crystal layer; Wherein said first electrode and said second electrode are arranged at the both sides of said electrically conerolled birefringence layer respectively, and under the effect of electric field that forms between said first electrode and said second electrode, said electrically conerolled birefringence crystal layer reflects the light through said zoom lens.

2. zoom lens according to claim 1 is characterized in that the width of said first electrode is less than the width of said second electrode.

3. zoom lens according to claim 1 is characterized in that, the direction of an electric field that forms between the incident direction of the light through said zoom lens and said first electrode and second electrode is parallel.

4. zoom lens according to claim 1 is characterized in that, said first electrode and said second electrode are transparency electrode.

5. according to each described zoom lens among the claim 1-4, it is characterized in that said electrically conerolled birefringence crystal layer is processed by the potassium dihydrogen phosphate crystal material.

6. zoom lens according to claim 5 is characterized in that, said electrically conerolled birefringence crystal layer thickness everywhere is identical.

7. zoom lens according to claim 6 is characterized in that, said electrically conerolled birefringence crystal layer is lens-shaped.

8. zoom lens according to claim 1 is characterized in that, the direction of an electric field that forms between the incident direction of the light through said zoom lens and said first electrode and second electrode is vertical.

9. zoom lens according to claim 8 is characterized in that, said electrically conerolled birefringence crystal layer is processed by the lithium columbate crystal material.

10. zoom lens according to claim 9 is characterized in that, said electrically conerolled birefringence crystal layer thickness everywhere is identical.

11. an imaging device is characterized in that, comprises each described zoom lens among the aforesaid right requirement 1-10.

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