JP2004004616A - Liquid crystal lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal lens that has a simple structure and that enables a focal point to be variably controlled very easily and quickly. <P>SOLUTION: The liquid crystal lens is equipped with a first substrate having a transparent first electrode, a second electrode having a hole, and a first liquid crystal layer which is stored between the first substrate and the second electrode in a manner opposing the first electrode and which has liquid crystal molecules oriented in one direction. This liquid crystal lens performs orientation control for the liquid crystal molecules by applying an electric voltage between the first and second electrodes. It is characterized in that a first insulation layer is arranged between the second electrode having the hole and the first liquid crystal layer. <P>COPYRIGHT: (C)2004,JPO

Description

（式中、Ｘは水素原子又はメチル基を表わし、６員環Ａ、Ｂ及びＣはそれぞれ独立に下記式（２）により表される原子団を表わし、ｎは０又は１を表わし、ｍは１〜４の整数を表わし、Ｙ^１及びＹ^２はそれぞれ独立に単結合、−ＣＨ_２ＣＨ_２−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＯＯ−、−ＯＣＯ−、−Ｃ≡Ｃ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−、−（ＣＨ_２）_４−、−ＣＨ_２ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２ＣＨ_２−、−ＣＨ_２＝ＣＨＣＨ_２ＣＨ_２−、又は−ＣＨ_２ＣＨ_２ＣＨ＝ＣＨ−を表わし、Ｙ^３は水素原子、ハロゲン原子、シアノ基、炭素原子数１〜２０のアルキル基、アルコキシ基、アルケニル基又はアルケニルオキシ基を表わす）
【化２】

【００６６】
なお、以上挙げた重合硬化性液晶には、重合硬化性を持たない液晶を添加してもよく、また従来公知の光重合開始剤、増感剤、保存安定剤等を添加することが出来る。
【００６７】
以上、本発明の実施形態に係る液晶レンズ及び高分子レンズについて説明したが、本発明は図１および図６に示す構造に限らず、種々変更を加えることが可能である。
【００６８】
また、以上説明した液晶レンズ又は高分子レンズを多数個、平面状に束ね、２次元アレイ状に配置することも可能である。
【００６９】
【発明の効果】
本発明によると、簡単な構成で、数１０ミクロン程度から数ｃｍ程度までの大きさの、焦点の位置を極めて容易に変えることが出来る、任意の形状寸法の液晶レンズ及び高分子レンズを提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る液晶レンズを示す断面図。
【図２】本発明の一実施形態に係る液晶レンズを２つの偏光板により挟み、電圧を印加することにより得た干渉パターンを示す図。
【図３】干渉パターンから誘導された光の相対位相リターデーションのプロファイルを示す特性図。
【図４】焦点面におけるライトスポットと集束ビームの強度分布を示す写真図。
【図５】印加電圧と焦点距離の関係を示す特性図。
【図６】本発明の他の実施形態に係る液晶レンズを示す断面図。
【図７】透明電極とアルミニウム薄膜電極との間に電圧を印加すると同時に、透明電極の両端部にも電圧を印加した場合の透明電極の両端部に印加された電圧と、焦点の位置との関係を示す解く製図。
【符号の説明】
１・・・下部基板
２・・・上部基板
３，１３・・・液晶層
４，１４・・・透明電極
５・・・アルミニウム薄膜電極
６・・・孔
７，８，１７，１８・・・ポリイミド膜
１１，１２・・・ガラス基板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal lens having a simple structure and capable of changing a focal length by an external voltage.
[0002]
[Prior art]
Liquid crystals have the characteristics of having fluidity like liquids, exhibiting anisotropic electrical and optical characteristics, and being able to control the molecular alignment state in various ways. In recent years, liquid crystal display devices using such characteristics of liquid crystal have been remarkably developed as thin and lightweight flat panel display devices.
[0003]
The alignment state of liquid crystal molecules can be easily controlled by treating the surface of a glass substrate provided with two transparent conductive films constituting a liquid crystal display element or by applying an externally applied voltage. It has an excellent characteristic that other optical materials can not continuously change the refractive index from a value for extraordinary light to a value for ordinary light.
[0004]
Until now, by using the electro-optic effect of nematic liquid crystal, unlike the parallel-plate type element structure in a normal liquid crystal display, the glass substrates with two transparent electrodes are tilted to each other to form a prism-shaped liquid crystal layer. And a variable focus lens in which the substrate surface is curved and the liquid crystal layer has a lens structure (for example, see Non-Patent Document 1 and Patent Document 1).
[0005]
A method of obtaining a lens effect by giving a spatial refractive index distribution to an optical medium is known, and is commercially available as a Selfoc lens. In a nematic liquid crystal cell, by utilizing the property that liquid crystal molecules are oriented in the direction of an electric field, it is possible to obtain a liquid crystal lens having spatial refractive index distribution characteristics due to the liquid crystal molecule alignment effect caused by an axisymmetric non-uniform electric field. Is known (for example, see Patent Document 2). Further, a lens using such a liquid crystal has a feature that it is relatively easy to form a microlens array in which a large number of minute lenses (microlenses) are two-dimensionally arranged in a flat plate shape.
[0006]
Unlike ordinary passive optical elements, these optical elements using liquid crystal can easily variably control the refractive index of the liquid crystal, which is the medium, by applying a voltage. It can be realized as a variable liquid crystal lens.
[0007]
Furthermore, a liquid crystal lens that forms a spatial distribution of potential by applying different voltages to electrodes of concentric annular zones and uses a spatial distribution of refractive index based on an alignment distribution of liquid crystal molecules has been reported. Attempts have been made to apply it to
[0008]
Generally, it is known that the response characteristic to an electric field when liquid crystal molecules are aligned in the direction of an electric field by applying a voltage in a nematic liquid crystal cell increases in substantially proportion to the square of the thickness of the liquid crystal layer. Further, when the thickness of the liquid crystal layer is about several hundreds of micrometers, the alignment effect of liquid crystal molecules due to the substrate interface of the liquid crystal cell does not reach the central region of the liquid crystal layer. Is also known.
[0009]
As described above, the liquid crystal lens can change the focal length by applying a voltage, but cannot change the focus in a direction perpendicular to the optical axis. On the other hand, two opposing electrodes having a circular hole pattern are divided by slits, and different voltages are applied to the respective divided electrodes to change the axially symmetric refractive index distribution to an asymmetric distribution, so that the incident light There is known a technique for causing a deflection effect on the focus and changing the position of the focal point in a direction perpendicular to the optical axis (for example, see Patent Document 3).
[0010]
[Non-patent document 1]
Applied Physics Vol. 45, No. 10, p. 938 (1976)
[0011]
[Patent Document 1]
JP-A-54-151854
[Patent Document 2]
JP-A-10-239676
[Patent Document 2]
JP-A-11-109304
[Problems to be solved by the invention]
Among the above-described prior arts, in the liquid crystal lens in which the liquid crystal layer has a lens structure, the thickness of the liquid crystal layer in the central portion of the lens in the case of a convex lens and the thickness of the liquid crystal layer in the peripheral portion of the lens in the case of a concave lens is increased. Therefore, when a lens having a diameter of several mm or more is to be formed, the thickness of the liquid crystal layer becomes several hundred microns or more, and the response recovery time requires a long time of several seconds to several tens of seconds. There was a problem of cloudiness.
[0015]
Also, when the liquid crystal molecules are realigned by the electric field, the direction in which the director of the liquid crystal rises from the substrate surface is opposite to each other near the center of the cell, so that a disclination line in which the liquid crystal molecule alignment is discontinuous is formed. This causes a problem that the optical characteristics of the lens deteriorate.
[0016]
On the other hand, in a liquid crystal microlens utilizing a spatial alignment distribution characteristic of liquid crystal molecules due to an axisymmetric non-uniform electric field, if only one substrate has a circular hole pattern, the optical characteristics of the lens are poor, and There is a problem that disclination lines are easily generated, and it is necessary to provide a circular hole pattern on both substrates. In this case, there is a problem that it is necessary to accurately match the positions of the hole-shaped patterns on both substrates.
[0017]
Further, it is known that when the ratio between the diameter of the circular hole pattern and the thickness of the liquid crystal layer is about 2: 1 to 3: 1, the characteristics as a lens are improved, but the diameter of the lens is about 1 mm. In this case, the thickness of the liquid crystal layer must be set to about several hundreds of micrometers, so that the above-described response characteristics are extremely slow, and there is a problem that the liquid crystal layer is clouded.
[0018]
In addition, the technique of splitting the electrodes with fine slits and applying different voltages to each other to generate a deflection effect on the incident light and change the focus in a direction perpendicular to the optical axis requires complicated liquid crystal lens structures and driving methods. And the disclination in which the orientation of the liquid crystal molecules is discontinuous between the electrodes often occurs.
[0019]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a liquid crystal lens having a simple structure and capable of variably controlling the focus very easily and quickly.
[0020]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a first substrate having a transparent first electrode, a second electrode having a hole, and the first substrate having a hole and the second electrode having a hole. A first liquid crystal layer in which liquid crystal molecules are oriented in one direction and is accommodated so as to face the first electrode, and a voltage is applied between the first electrode and the second electrode to apply a voltage to the liquid crystal molecules. A liquid crystal lens which performs alignment control, wherein a first insulating layer is provided between a second electrode having the hole and the first liquid crystal layer.
[0021]
In the liquid crystal lens according to the present invention, it is possible to adopt a configuration in which two liquid crystal lenses are stacked back to back with the second electrode having a hole in common. That is, a second substrate having a transparent third electrode was provided on the second electrode, and was accommodated between the second substrate and the second electrode so as to face the third electrode. The liquid crystal display device may further include a second liquid crystal layer in which liquid crystal molecules are aligned in one direction, and a second insulating layer may be provided between the second electrode having holes and the second liquid crystal layer. .
[0022]
In addition, a light blocking member having an opening smaller in size than the hole and for restricting light passing through the hole can be provided around the hole of the second electrode.
[0023]
The holes in the second electrode may be of any shape, for example, circular, elliptical, quadrangular, hexagonal, or polygonal.
The liquid crystal lens of the present invention configured as described above has a very simple structure, and the focal length can be easily changed by applying a voltage between the first and second electrodes. Can be configured.
[0024]
The liquid crystal lens according to the present invention can further include means for forming a potential gradient on the first electrode. The means for forming a potential gradient on the first electrode may be a means for applying a voltage between electrodes attached to both ends in a direction perpendicular to an optical axis passing through the first electrode.
[0025]
In this case, the first electrode preferably has a relatively high resistance, for example, an electric resistance of 100Ω to 1MΩ.
[0026]
By forming a potential gradient on the first electrode in this manner, light passing through the liquid crystal layer can be deflected, so that the position of the focal point of the liquid crystal lens can also be changed in a direction perpendicular to the optical axis. I can do it.
[0027]
The liquid crystal lenses described above can be arranged in a two-dimensional array to form a liquid crystal lens array.
[0028]
In the above liquid crystal lens, the first liquid crystal layer is composed of a polymerizable and curable liquid crystal, and a predetermined voltage is applied to the first liquid crystal layer to control the alignment of liquid crystal molecules in an ultraviolet or visible light state. The polymer lens can be obtained by irradiating and curing. By controlling the voltage applied to the liquid crystal layer, the position of the focal point of the polymer lens can be easily adjusted three-dimensionally, so that a high-precision lens can be obtained.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0030]
FIG. 1 is a sectional view showing a cell configuration of a liquid crystal lens according to one embodiment of the present invention. In FIG. 1, a liquid crystal layer 3 is sandwiched between a pair of glass substrates 1 and 2. A surface of the lower substrate 1 facing the liquid crystal layer 3 is covered with a transparent electrode 4 made of ITO (indium tin oxide). The surface of the upper substrate 2 opposite to the surface facing the liquid crystal layer 3 is coated with an aluminum thin film electrode 5, and a circular hole 6 is formed in the center of the aluminum thin film electrode 5.
[0031]
No electrode is formed on the surface of the upper substrate 2 facing the liquid crystal layer 3, and therefore, the insulating layer as the glass substrate 2 is interposed between the aluminum thin film electrode 5 and the liquid crystal layer 3. Become.
[0032]
In the liquid crystal lens according to the present embodiment, the thickness of the liquid crystal layer 3 is 130 μm, the thickness of the substrates 1 and 2 is 1.3 mm, and the diameter of the hole 6 is 7.0 mm, but these values are variously changed. It is possible.
[0033]
However, in the liquid crystal lens according to the present embodiment, the thickness of the upper substrate 2 is particularly important because it defines the distance between the aluminum thin film electrode 5 and the liquid crystal layer 3. The thickness of the upper substrate 2 is desirably 1 μm to 5 mm, particularly preferably several μm to several mm, for example, 2 μm to 3 mm. That is, the upper substrate 2 is not limited to a glass substrate, but may be another insulating layer. In this case, a separate substrate may be used to hold the thin insulating layer. As the insulating layer, a silicon oxide film, a silicon nitride film, or the like can be used.
[0034]
In addition, the diameter of the hole 6 is desirably about several μm to several tens mm, but is not particularly limited.
The surfaces of the lower substrate 1 and the upper substrate 2 facing the liquid crystal layer 3 are respectively coated with polyimide films 7 and 8, and their surfaces are rubbed in one direction so that the liquid crystal molecules are uniformly arranged. I have.
[0035]
A light blocking member that has an opening smaller in size than the hole 6 around the hole 6, for example, between the upper substrate 2 and the aluminum thin film electrode 5, that is, a so-called black matrix that restricts light passing through the hole 6. May be provided. That is, although the characteristics of the peripheral portion of the hole 6 are poor, by providing the black matrix, good characteristics can be obtained also in the peripheral portion of the hole 6. Carbon or the like can be used as the black matrix.
[0036]
In the liquid crystal lens shown in FIG. 1 configured as described above, the upper substrate 2 is interposed between the aluminum thin film electrode 5 having the hole 6 and the liquid crystal layer 3, and therefore, both are at a certain distance. Therefore, a non-uniform electric field generated by a voltage applied between the aluminum thin-film electrode 5 and the transparent electrode 4 is distributed over a wide area of the liquid crystal layer 3, and a gradient index distribution is formed in the area. Is done. In this way, a large size lens is realized.
[0037]
The refractive index distribution changes according to the applied voltage. Therefore, the focal length of the lens is a function of the external voltage, and the focal length of the lens can be arbitrarily changed by the external voltage.
[0038]
In order to test the phase profile of the extraordinary light component of the emitted light, a liquid crystal lens was disposed between two polarizing plates whose polarization axes were orthogonal to each other. Further, the rubbing direction of the polyimide films 7 and 8 was set to make an angle of π / 4 with the polarization axis of each of the two polarizing plates.
[0039]
FIG. 2 shows an interference pattern between an extraordinary ray and an ordinary ray when a voltage of 35 Vrms at a frequency of 1 kHz is applied between the first and second electrodes. The number and position of the interference rings change with the applied voltage. The phase difference between two adjacent rings is 2π. Since the phase retardation of the ordinary ray is the same everywhere in the region of the hole 6, the interference pattern represents the phase retardation profile of the incident light linearly polarized in the rubbing direction.
[0040]
FIG. 3 shows a profile of relative phase retardation of light guided from the interference pattern. In the figure, black circles and white circles are measurement points, and curves are quadratic curves. Open circles indicate the results measured along the rubbing direction, and black circles indicate the results measured along the perpendicular direction.
[0041]
Extraordinary rays emanating from the position of the outermost ring of the interference pattern are considered to have zero phase retardation. The approximate quadratic curve of the phase retardation shows that this liquid crystal lens behaves like an optical lens with appropriate geometric parameters.
[0042]
As in the case of the conventional liquid crystal microlens, the profile of the phase retardation along the rubbing direction is different from the profile of the phase retardation along the vertical direction. Furthermore, the phase retardation profile along the direction perpendicular to the rubbing direction is symmetric, while the phase retardation profile along the rubbing direction is asymmetric due to the director pretilt angle at the substrate surface. Asymmetry is reduced by reducing the pretilt angle.
[0043]
FIG. 4 shows a photograph of the light spot and the intensity distribution of the focused beam at the focal plane when the applied voltage is 35 Vrms. From this figure, it is calculated that the full width at half maximum (FWHM) of the spot is about 100 μm.
[0044]
The focal length of the liquid crystal cell changes depending on the applied voltage. FIG. 5 shows the focal length as a function of the applied voltage. The focusing force first varies with voltage. The minimum focal length is about 76 cm and is obtained around 35 Vrms. As the voltage continues to increase, the director near the center continues to rotate, while the director near the hole saturates. The refractive index profile is flattened and the focal length is longer.
[0045]
The phase retardation profile can be adjusted by the hole diameter and the thickness of the substrate. For good performance, it is necessary to increase the size of the holes according to the thickness of the substrate. In such a structure, a liquid crystal lens of almost any size can be realized by using glass substrates or thin films of various thicknesses as the intermediate insulating layer.
[0046]
In the present invention, the liquid crystal layer can be made thinner, so that the operation speed can be made much higher than that of the conventional liquid crystal lens. Further, the distribution of the electric field in the liquid crystal in the structure of the liquid crystal lens is different from the distribution of the electric field in the conventional liquid crystal molecules. That is, in conventional liquid crystal microlenses, the electric field at the boundaries of the holes is tilted, which allows the director in various parts to rotate in opposite directions, causing disclination lines at high voltages.
[0047]
On the other hand, in the cell structure of the liquid crystal lens of the present invention, the electric field is perpendicular to the plane in the vicinity of a conductor such as a metal, so that the electric field and the director at an arbitrary position of the liquid crystal lens are interposed. The angles are almost identical, and all directors rotate in the same direction. Therefore, no disclination line occurs even when a voltage is applied. This indicates that a high voltage can be applied to increase the operation speed.
[0048]
In a typical liquid crystal microlens, it has been found that a structure having two overlapping holes has higher performance than a structure having one hole. Also in the present invention, it is possible to provide a configuration in which both electrodes are provided with circular holes, and the two electrodes are separated by a glass substrate.
[0049]
However, since the thickness of the glass substrate is much larger than the thickness of the liquid crystal layer, if the influence of the director rearrangement on the electric field can be neglected, the conventional two-hole structure and the present invention can be used in terms of the electric field distribution of the liquid crystal. There is almost no difference from the structure of FIG. The electrode structure of the present invention has the advantage that the operating voltage is half of the operating voltage required for a conventional two-hole structure and is very simple to manufacture.
[0050]
As a modification of the embodiment shown in FIG. 1, there is a liquid crystal lens in which a potential gradient is formed on the transparent electrode 4. That is, in the liquid crystal lens shown in FIG. 1, the transparent electrode 4 is made of a material having a relatively high resistance, and a voltage is applied between the transparent electrode 4 and the aluminum thin film electrode 5 and at the same time, both ends of the transparent electrode 4 are applied. By applying a voltage, a potential gradient can be formed on the transparent electrode 4. The liquid crystal molecules of the liquid crystal layer 3 are oriented in the direction of the potential gradient due to the potential gradient formed on the transparent electrode 4. As a result, the refractive index distribution that was axially symmetric when there is no potential gradient in the transparent electrode 4 becomes an asymmetric distribution in the direction of the potential gradient, and an effect is obtained that incident light is deflected from the direction in which it goes straight.
[0051]
In this case, the direction of deflection of incident light can be changed by appropriately changing the portion of the transparent electrode 4 to which the voltage is applied, that is, the positions of the electrodes provided at both ends of the transparent electrode 4.
[0052]
As a material having a relatively high resistance for forming the transparent electrode 4, for example, a material obtained by adding indium oxide to zinc oxide or tin oxide can be used. The electric resistance is preferably about 100Ω to 1MΩ.
[0053]
FIG. 7 shows a configuration in which a liquid crystal lens is formed using a transparent electrode 4 having a resistance of about 10 kΩ, which is formed by high-frequency sputtering using a target obtained by adding about 5% of indium oxide to zinc oxide. 5 is a graph showing the relationship between the voltage applied to both ends of the transparent electrode 4 and the position of the focal point when a voltage is applied to both ends of the transparent electrode 4 at the same time when a voltage is applied to the transparent electrode 4. . Note that the focal length changes by changing the voltage applied between the transparent electrode 4 and the aluminum thin film electrode 5.
[0054]
From FIG. 7, it is possible to obtain a three-dimensional focus variable characteristic by changing the voltage applied between the transparent electrode 4 and the aluminum thin film electrode 5 and the voltage applied to both ends of the transparent electrode 4. You can see that there is.
[0055]
Conventionally, light could not be deflected by an electric or magnetic field, but light can be easily deflected by giving a potential gradient to the transparent electrode 4, and as a result, the focal point can be changed three-dimensionally. A possible liquid crystal lens can be realized. This liquid crystal lens can be applied to various wide-ranging applications such as an optical switch in free space and a switch between optical fibers.
[0056]
FIG. 6 is a sectional view showing a liquid crystal lens according to another embodiment of the present invention. The same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0057]
The liquid crystal lens shown in FIG. 6 has a configuration in which two liquid crystal lenses are stacked back to back using the same aluminum thin film electrode 5. That is, a glass substrate 12 is disposed on the aluminum thin film electrode 5, a glass substrate 11 having a transparent electrode 14 is disposed on the glass substrate 12, and a liquid crystal layer 13 is further provided between the glass substrate 11 and the glass substrate 12. Is contained. In this case, the surfaces of the glass substrates 11 and 12 facing the liquid crystal layer 13 are covered with polyimide films 17 and 18, respectively, and those surfaces are rubbed in one direction so that the liquid crystal molecules are uniformly arranged. ing.
[0058]
In the liquid crystal lens having such a structure, the rubbing direction of the polyimide films 7 and 8 and the rubbing direction of the polyimide films 17 and 18 are set to be the same and the focal length can be shortened by sandwiching the two polarizing plates.
[0059]
Further, by making the rubbing directions of the polyimide films 7 and 8 perpendicular to the rubbing directions of the polyimide films 17 and 18, the liquid crystal lens can be operated without disposing a polarizing plate.
[0060]
The liquid crystal lens according to the embodiment shown in FIG. 6 can also be configured to deflect incident light. That is, by attaching electrodes to both ends of the transparent electrode 4, applying a voltage, and providing a potential gradient to the transparent electrode 4, light incident on the liquid crystal layer 3 can be deflected and the position of the focal point can be changed.
[0061]
According to still another embodiment of the present invention, in the liquid crystal lens shown in FIG. 1, a liquid crystal polymerizable and cured by ultraviolet light or visible light is used as the liquid crystal layer 3, and a voltage is applied to the liquid crystal layer 3 via the transparent electrode 4 and the aluminum electrode 5. In this state, the liquid crystal layer 3 is irradiated with ultraviolet light or visible light to cure the liquid crystal, thereby obtaining a polymer lens whose focal point is controlled to a predetermined position. The position of the focal point may be controlled not only in the direction of the optical axis but also in the direction perpendicular to the optical axis by providing a potential gradient to the transparent electrode 4 by the above-described method.
[0062]
In the present embodiment, UCL-001 (trade name: manufactured by Dainippon Ink Co., Ltd.) is used as the polymerizable liquid crystal, and 50 V _rms is applied to the liquid crystal layer 3 via the transparent electrode 4 and the aluminum electrode 5. The liquid crystal layer 3 was irradiated with 10 mW ultraviolet light for 10 minutes by a high pressure mercury lamp. As a result, the liquid crystal was photopolymerized and cured. Even when the application of the voltage was released, the alignment state of the liquid crystal molecules did not change, and the lens characteristics were maintained.
[0063]
Thereafter, the polymer film in which the liquid crystal layer 3 was polymerized and cured was peeled off from the substrate and removed, whereby a plastic film-shaped polymer lens could be obtained.
[0064]
As the polymerizable curable liquid crystal that can be used in the present embodiment, for example, a compound represented by the following general formula (1) can be preferably used.
[0065]
Embedded image

(Wherein, X represents a hydrogen atom or a methyl group, 6-membered rings A, B and C each independently represent an atomic group represented by the following formula (2), n represents 0 or 1, and m represents Y ¹ and Y ² each independently represent a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —C≡C _{-, - CH = CH -,} - CF = CF -, - (CH 2) 4 -, - CH 2 CH 2 CH 2 O -, - OCH 2 CH 2 CH 2 -, - CH 2 = CHCH 2 CH 2 - , or _-CH 2 _CH 2 _CH = CH- and represents, ^{Y 3} represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group, an alkenyl group or alkenyloxy group)
Embedded image

[0066]
In addition, a liquid crystal having no polymerization curability may be added to the above-mentioned polymerization curable liquid crystal, and a conventionally known photopolymerization initiator, sensitizer, storage stabilizer and the like can be added.
[0067]
As described above, the liquid crystal lens and the polymer lens according to the embodiment of the present invention have been described. However, the present invention is not limited to the structures shown in FIGS. 1 and 6, and various changes can be made.
[0068]
It is also possible to bundle a large number of the above-described liquid crystal lenses or polymer lenses in a planar shape and arrange them in a two-dimensional array.
[0069]
【The invention's effect】
According to the present invention, there are provided a liquid crystal lens and a polymer lens having a simple configuration and a size from about several tens of microns to about several centimeters and having an arbitrary shape and size in which the position of a focal point can be changed very easily. be able to.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a liquid crystal lens according to an embodiment of the present invention.
FIG. 2 is a diagram showing an interference pattern obtained by sandwiching a liquid crystal lens according to an embodiment of the present invention between two polarizing plates and applying a voltage.
FIG. 3 is a characteristic diagram showing a profile of relative phase retardation of light guided from an interference pattern.
FIG. 4 is a photograph showing an intensity distribution of a light spot and a focused beam on a focal plane.
FIG. 5 is a characteristic diagram showing a relationship between an applied voltage and a focal length.
FIG. 6 is a sectional view showing a liquid crystal lens according to another embodiment of the present invention.
FIG. 7 shows the relationship between the voltage applied to both ends of the transparent electrode and the focus position when a voltage is applied between the transparent electrode and the aluminum thin-film electrode at the same time that a voltage is applied to both ends of the transparent electrode. Solving drafting showing the relationship.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Lower board | substrate 2 ... Upper board | substrate 3, 13 ... Liquid crystal layer 4, 14 ... Transparent electrode 5 ... Aluminum thin film electrode 6 ... Holes 7, 8, 17, 18 ... Polyimide films 11, 12 ... glass substrate

Claims (9)

A first substrate having a transparent first electrode, a second electrode having a hole, and being accommodated between the first substrate and the second electrode so as to face the first electrode. A liquid crystal lens comprising a first liquid crystal layer in which liquid crystal molecules are aligned in one direction, and applying a voltage between the first electrode and the second electrode to control alignment of the liquid crystal molecules; A liquid crystal lens, comprising a first insulating layer disposed between a second electrode having the first electrode and the first liquid crystal layer. A second substrate having a transparent third electrode on the second electrode, and a second substrate disposed between the second substrate and the second electrode so as to face the third electrode; A second liquid crystal layer in which liquid crystal molecules are aligned in one direction, and a second insulating layer is disposed between the second electrode having the holes and the second liquid crystal layer. The liquid crystal lens according to claim 1, wherein 3. A light blocking member having an opening smaller in size than the hole and configured to restrict light passing through the hole is provided around the hole of the second electrode. The liquid crystal lens according to 1. The liquid crystal lens according to any one of claims 1 to 3, wherein the hole of the second electrode is circular, elliptical, quadrangular, hexagonal, or polygonal. The liquid crystal lens according to claim 1, further comprising a unit configured to form a potential gradient on the first electrode. The means for forming a potential gradient in the first electrode is means for applying a voltage between electrodes attached to both ends in a direction perpendicular to an optical axis passing through the first electrode. Item 6. A liquid crystal lens according to item 5. The liquid crystal lens according to claim 5, wherein the first electrode has an electric resistance of 100Ω to 1 MΩ. A liquid crystal lens array, wherein the liquid crystal lenses according to claim 1 are arranged in a two-dimensional array. The first liquid crystal layer of the liquid crystal lens according to any one of claims 1 to 7, wherein the first liquid crystal layer is made of a polymer curable liquid crystal. A polymer lens that is cured by irradiating ultraviolet or visible light under controlled conditions.

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