JPH112802A - Liquid crystal optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the driving voltage and charge holding rate of the liquid crystal optical element by preventing a pigment material from being mixed with liquid crystal drops by introducing a photopolymerizing base into a pigment material, copolymerizing it with the precursor of high polymer resin, and fixing the pigment material in the high polymer resin. SOLUTION: A dimming layer formed of the high polymer resin 4 and a liquid crystal material is sandwiched between a transparent electrode 1 which has an electrode layer 2 and a light absorbing substrate 5 which has an electrode layer 2. The pigment material is fixed and contained in this high polymer resin 4 and also arrayed regularly in liquid crystal drops 3. Further, the fixation of the pigment material in the high polymer resin 4 is performed by the photopolymerization between the precursor of the high polymer resin 3 and the pigment material. The photopolymerizing base of the pigment material is a (meth)acrylyl base. Thus, the photopolymerizing base is introduced into the pigment material, copolymerized with the precursor of the high polymer resin 4, and fixed in the high polymer resin 4 to prevent the pigment material from being mixed with liquid crystal drops 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal optical element which becomes a selective reflection state of visible light when no voltage is applied and becomes a light absorbing state when a voltage is applied. It is used for a display device or the like for displaying the information.

[0002]

2. Description of the Related Art One of the solutions for improving the operation time of a portable terminal using a liquid crystal display is to use a device which does not require a backlight as a liquid crystal optical element, that is, a reflection type liquid crystal optical element. As for the reflection type, a GH (guest-host) mode and an electric field controlled birefringence (ECB) mode have been reported. In addition, international application 9
In the method disclosed in Japanese Patent Application Publication No. 2/19695, in which a trace amount of a polymer compound is dispersed in a chiral nematic liquid crystal, the liquid crystal phase forms a planar texture in the absence of an electric field, becomes a state of selectively reflecting visible light, and is exposed to a voltage. A liquid crystal optical element which forms a focal conic texture and is translucent has been obtained. This liquid crystal optical element, which is generally called a polymer-stabilized cholesteric texture (PSCT) element, selectively reflects / reflects a phase change of a chiral nematic liquid crystal.
Utilizing the property of semi-transmission, a reflective liquid crystal optical element capable of taking a selective reflection state and a light absorption state can be manufactured by combining with a light absorption layer. Further, since the reflection type liquid crystal optical element has bistability, it can be driven by a simple matrix.

On the other hand, Japanese Patent Application Laid-Open No. 5-134266 discloses a reflection type liquid crystal element composed of a liquid crystal and a polymer. In the liquid crystal optical element of the disclosed technology, the reflection / transmission of light is controlled by using light interference caused by a difference in refractive index between a regularly arranged liquid crystal droplet and a polymer material. It is called an element.

This liquid crystal optical element is disclosed in Japanese Patent Publication No. 3-5284.
As in the transmission / scattering type liquid crystal optical element in which a liquid crystal is encapsulated and dispersed in a polymer material as disclosed in Japanese Patent Publication No. 3 (1993), etc., a polarizing plate is not required, so that the light use efficiency is high,
(A thin film transistor) and an MIM can be driven by an active element. In the liquid crystal optical element, a liquid crystal optical element having different selective reflection wavelengths can be manufactured by setting the interval between liquid crystal droplets. Therefore, by juxtaposing or laminating pixels that selectively reflect RGB wavelengths, multicoloring can be performed without a color filter. realizable.

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 5-134 is disclosed.
The holographic polymer-dispersed liquid crystal disclosed in Japanese Patent Publication No. 266 is manufactured by photo-curing with visible light, and therefore absorbs visible light to absorb energy in addition to a photopolymerization initiator used by ordinary ultraviolet curing. It is necessary to add a dye material that transfers to a photopolymerization initiator to generate radicals. However, when a holographic polymer-dispersed liquid crystal is prepared by adding a dye material as disclosed in JP-A-5-80308 to a mixture of a polymer resin precursor and a liquid crystal material, There is a disadvantage that the dye material is mixed and the driving voltage of the liquid crystal optical element is increased and the charge retention rate is reduced.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have introduced a photopolymerizable group into a dye material and copolymerized with a polymer resin precursor. The present invention has been found that the immobilization in the polymer resin prevents the coloring material from being mixed into the liquid crystal droplets and improves the driving voltage and the charge retention of the liquid crystal optical element.

The present invention is as follows. 1. In a liquid crystal optical element in which a light modulating layer made of a polymer resin and a liquid crystal material is sandwiched between a transparent substrate having an electrode layer and a light absorbing substrate having an electrode layer, a dye material is fixed in the polymer resin. A liquid crystal optical element, wherein the liquid crystal material is included and the liquid crystal material is regularly arranged in the form of drops. 2. 2. The liquid crystal optical element according to item 1, wherein the fixation of the dye material in the polymer resin is performed by photopolymerization of a precursor of the polymer resin and the dye material. 3. 3. The liquid crystal optical element according to the above item 1 or 2, wherein the photopolymerizable group of the coloring material is a (meth) acryloyl group. 4. 4. The liquid crystal optical element according to the above item 1, 2 or 3, wherein the dye material has a light absorption characteristic in a visible light region. 5. 5. The liquid crystal optical element according to the above 1, 2, 3 or 4, wherein the dye material is a mixture of two or more dye materials having different light absorption wavelengths. 6. 5. The liquid crystal optical element according to the above 1, 2, 3 or 4, wherein the dye material is a coumarin dye derivative. 7. 5. The liquid crystal optical element according to the above 1, 2, 3 or 4, wherein the dye material is a styryl dye derivative. 8. 3. The liquid crystal optical element according to the above 1 or 2, wherein the precursor of the polymer resin has a (meth) acryloyl group. 9. 2. The liquid crystal optical element according to the above item 1, wherein the ordinary light refractive index of the liquid crystal material matches the refractive index of the polymer resin. 10. The above-mentioned items 1 to 9, wherein the device is in a state of selectively reflecting visible light when no voltage is applied, and in a light absorbing state when voltage is applied.
3. The liquid crystal optical element according to item 1.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A liquid crystal optical element of the present invention is obtained by irradiating a mixed solution of a precursor of a polymer resin, a photopolymerization initiator, a dye material having a photopolymerizable group and a liquid crystal material with visible light that has interfered. Photocuring is performed to produce a light control layer in which liquid crystal droplets are regularly arranged in a polymer resin. At this time, the coloring material is copolymerized with the precursor compound of the polymer resin and fixed in the polymer resin.

More specifically, visible light that has interfered with a mixed solution of a pigment material having a (meth) acryloyl group, a precursor of a polymer resin having a (meth) acryloyl group, and a photopolymerization initiator by a two-beam interference method. Irradiation and light curing. At this time, the irradiated light is absorbed by the dye material. The excitation energy of the dye material is transferred to the photopolymerization initiator to generate a radical. This radical moves to the vinyl group of the precursor of the polymer resin, and the polymerization proceeds. At this time, the coloring material having a (meth) acryloyl group is copolymerized with the precursor of the polymer resin and is taken into the polymer resin. Photopolymerization proceeds in a portion where the laser light intensity is high, and a light control layer in which liquid crystal droplets are regularly arranged in a polymer resin is produced.

The liquid crystal optical element disclosed in Japanese Patent Publication No. 62-502780 also contains a dye material, but the dye used in this element is a dichroic dye. Also, the pigment material is dispersed in the liquid crystal droplets,
Controls the absorption and transmission of light in response to the orientation of the liquid crystal. Therefore, in order to improve the contrast of the device, the pigment material is not dispersed in the polymer resin, but is dispersed in the liquid crystal material.

On the other hand, JP-A-5-346574 discloses a polymer-dispersed liquid crystal optical element in which a photopolymerization initiator for curing a precursor of a polymer resin has a polymerizable group. In this device, ultraviolet light is used as light for curing the precursor of the polymer resin, and the irradiation of the ultraviolet light causes the photopolymerization initiator to generate radicals to initiate polymerization, and the photopolymerization initiator itself also polymerizes. I do. It is described that the photopolymerization initiator is copolymerized in the polymer resin instead of in a free state after the polymerization, thereby preventing a decrease in the charge retention of the device. Also, in this disclosed technique, a dichroic dye material is dispersed in liquid crystal droplets as in a liquid crystal optical element disclosed in Japanese Patent Application Laid-Open No. 62-502780. Controls absorption and transmission.

On the other hand, in the liquid crystal optical element of the present invention,
The excitation energy of the dye material that absorbs visible light is transferred to the photopolymerization initiator having no polymerizable group, and the photopolymerization initiator generates radicals, which are (meth) acryloyl, a precursor of the polymer resin. It moves to the base and the polymerization proceeds. At this time, the dye material having a (meth) acryloyl group is copolymerized and taken into the polymer resin, so that the concentration of the dye material mixed into the liquid crystal droplet is reduced. Thereby, a reduction in the driving voltage of the liquid crystal material can be achieved. In addition, it is generally known that a photopolymerization initiator is fixed to a terminal of a polymer during polymerization, and it is not necessary to copolymerize with a polymer resin in order to prevent a decrease in charge retention. In a liquid crystal optical element, by setting the concentration to an appropriate value, the charge retention does not decrease.

The dye material having a photopolymerizable group in the present invention includes a coumarin dye having a (meth) acryloyl group, a rhodamine dye, an oxazine dye, a carbocyanine dye, a dicarbocyan dye, a tricarbocyan dye, Tetracarbocyan dyes, pentacarbocyan dyes, oxonol dyes, styryl dyes, xanthene dyes, merocyanine dyes, rhodocyanine dyes, porphyrin dyes, acridine dyes, and the like, but are not limited thereto. Not something. The dye material is excited by a visible light laser to transfer energy to the start of photopolymerization, and may be any material having photopolymerizability such as a (meth) acryloyl group. In the present invention, the (meth) acryloyl group means an acryl group and a methacryloyl group, or the dye material having a (meth) acryloyl group means that the molecule contains at least an acryl group and / or a methacryloyl group. A spacer such as an oxy group, a methacryloyloxy group, an acryloyloxymethyl group, a methacryloyloxymethyl group may be present.

The light control layer of the present invention is a layer in which liquid crystal materials are regularly arranged in a droplet form in a polymer resin containing a dye material. This layer can be formed by irradiating a mixed solution of a precursor of a polymer resin, a photopolymerization initiator, a dye material having a photopolymerizable group, and a liquid crystal material with visible light that interferes.

Since the refractive index of the polymer resin is set at or near the ordinary refractive index (n _o ) of the liquid crystal material, when no voltage is applied, light passes through the light control layer and is absorbed by the light absorbing substrate. , Resulting in a black display. Also, when a voltage is applied, a difference in refractive index occurs between the polymer resin and the liquid crystal droplets that are regularly arranged,
Selective reflection occurs in the light control layer.

The material of the transparent substrate used in the present invention can be glass, plastic, or the like. The substrate is set so that the electrode layer is on the light control layer side. IT as material for electrode layer
A material such as O can be used, but if the substrate used has conductivity, the substrate can also be used as an electrode. The substrate is set so that the electrode layer is on the light control layer side.

The light absorbing plate may be made of an inorganic material or an organic material as long as it is made of a material that absorbs visible light. The absorption intensity or absorption wavelength can be arbitrarily changed depending on the target device characteristics. The light-absorbing material may be formed by coating the light-absorbing material on a transparent substrate such as glass or plastic, or may be manufactured by bonding the light-absorbing substrate on the transparent substrate.

For the setting of the distance between the substrates, a rod-shaped or spherical spacer made of glass or a polymer resin or the like, which is used for ordinary liquid crystal devices, can be used, and the distance is desirably about 5 μm or more and 30 μm or less.

The substrate with an electrode layer need not be treated so that the liquid crystal is oriented, but may be treated. For these alignment treatments, a normal alignment film such as polyimide used for TN liquid crystal and STN liquid crystal can be used.
A rubbing treatment may be performed.

As the liquid crystal material used for the liquid crystal optical element of the present invention, a usual nematic liquid crystal can be used. The material may be a cyano-based, fluorine-based, chlorine-based, or any other material, but a fluorine-based liquid crystal having a high charge retention rate is required for active driving by an active element such as a thin film transistor (TFT). desirable.

The liquid crystal optical element of the present invention can be manufactured by sandwiching a mixture of a liquid crystal material, a photopolymerization initiator and a precursor of a polymer resin between substrates having a fixed gap, and irradiating the mixture with visible light. it can. At this time, the mixture may be injected under reduced pressure or normal pressure. If necessary, heating may be performed.

As the precursor of the polymer resin, a monomer or oligomer or a mixture of monomer and oligomer which can be polymerized by light irradiation can be used.
That is, any polymer precursor having a photopolymerizable group composed of a normal vinyl group such as an acryloyl group and a methacryloyl group can be used. A plurality of photopolymerizable groups may be present in one molecule of the polymer precursor. As the monomer, for example, 2-ethylhexyl acrylate, butylethyl acrylate, butoxyethyl acrylate,
2-cyanoethyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-hydroxypropyl acrylate, 2-ethoxyethyl acrylate,
N, N-diethylaminoethyl acrylate, N, N-
Monofunctional acrylates such as dimethylaminoethyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, isobonyl acrylate, isodecyl acrylate, lauryl acrylate, morpholine acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate Compound, 2-ethylhexyl methacrylate, butylethyl methacrylate, butoxyethyl methacrylate,
-Cyanoethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, 2-hydroxypropyl methacrylate, 2-ethoxyethyl acrylate, N, N-diethylaminoethyl methacrylate,
N, N-dimethylaminoethyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, isobonyl methacrylate, isodecyl methacrylate, lauryl methacrylate, morpholine methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, etc. Monofunctional methacrylate compound, diethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, dicyclopentanyl diacrylate, glycerol diacrylate, 1,6-hexanediol diacrylate, neopentyl Glycol diacrylate, tetraethylene glycol Polyfunctional acrylate compounds such as acrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, urethane acrylate oligomer, diethylene glycol di Methacrylate, 1,4
-Butanediol dimethacrylate, 1,3-butylene glycol dimethacrylate, dicyclopentanyl dimethacrylate, glycerol dimethacrylate, 1,6
-Hexanediol dimethacrylate, neopentyl glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol trimethacrylate, ditrimethylolpropane tetramethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol mono Examples include, but are not limited to, polyfunctional methacrylate compounds such as hydroxypentamethacrylate and urethane methacrylate oligomers.

The polymer resin is desirably contained in the nematic liquid crystal in an amount of from 20% by weight to 80% by weight. If the amount of the polymer resin is too large, the driving voltage of the element becomes high. If the amount is too small, the regular arrangement of the liquid crystal droplets is not formed and the reflectance of visible light is reduced.

Usable photopolymerization initiators include acetophenone-based, benzoin-based, benzophenone-based, and thioxanthone-based photopolymerization initiators. For example, diethoxyacetophenone, 2-hydroxy-2-methyl-
Examples include 1-phenylpropan-1-one, benzoin methyl ether, benzoin ethyl ether, 4-phenylbenzophenone, 2-chlorothioxanthone, and 2-methylthioxanthone. The initiator may be a solid or a liquid, but it is desirable that the initiator be dissolved or compatible with the liquid crystal in view of the uniformity of the device. The initiator concentration was 30 for the polymer resin precursor.
% By weight or less is preferred. If necessary, a photoinitiating auxiliary such as methyldiethanolamine and 4-dimethylaminobenzoic acid can be added.

As a light source used for photopolymerization of the precursor of the polymer resin, a visible light laser such as an argon ion laser and a helium neon laser can be used. Photocuring by laser light is performed by a two-beam interference method. That is, curing is performed in a state where two laser beams are incident on the substrate and the laser beams interfere with each other. In order to obtain multi-color selective reflection of red, green and blue, the incident angle of the laser is adjusted or laser light sources having different wavelengths are used. When irradiating different light to each domain, a light shielding film such as a photomask can be used.

[0026]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

The driving voltage and the charge retention described in the embodiments of the present invention are defined as follows.

Driving voltage: In the light reflectance-voltage curve,
Assuming that the lowest value of the reflectance is R _min (%) and the highest value of the reflectance is R _max (%), the driving voltage V ₁₀ is the light reflectance R
(%) Is the applied voltage at which the light reflectance R ₁₀ of formula (1).

R ₁₀ = 0.1 × (R _max −R _min ) + R _min (1) Charge retention: A pulse voltage having a pulse width of 60 μs and an amplitude of 5 V is applied to the element. Assuming that the voltage held by the element within 16.7 ms after the pulse application is V, the charge retention (%) is expressed by equation (2).

Charge retention = (V / 5) × 100 (2) Example 1 In a liquid crystal cell having a gap of 6 μm composed of a glass substrate with ITO and a light absorbing substrate with ITO, a precursor of a polymer resin Mixture of hexapentenyl diacrylate and urethane acrylate oligomer, nematic liquid crystal E8 having a positive dielectric anisotropy (manufactured by Merck), styryl dye material 3- (acryloyloxymethyl) -4- (dicyanomethylene) -2 A mixed solution of -methyl-6- (p-dimethylaminostyryl) -4H-pyran and a polymerization initiator benzoin methyl ether was injected under reduced pressure. The liquid crystal cell was irradiated with an argon laser having a wavelength of 488 nm by a two-beam interference method to perform photopolymerization. The obtained liquid crystal optical element showed a blue reflection state when no voltage was applied. An AC voltage of 100 Hz was applied to the device, and the reflectance of light having a wavelength of 488 nm was measured. The light reflectance decreased as the applied voltage increased. Driving voltage V ₁₀ was 19.5V.

Example 2 A mixture of hexapentenyl diacrylate and urethane acrylate oligomer, which are precursors of a polymer resin, in a liquid crystal cell having a gap of 6 μm composed of a glass substrate with ITO and a light-absorbing substrate with ITO, Nematic liquid crystal TL215 (manufactured by Merck) having positive anisotropy, styryl dye material 3- (acryloyloxymethyl) -4-
A mixed solution of (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran and a polymerization initiator benzoin methyl ether was injected under reduced pressure. The liquid crystal cell was irradiated with an argon laser having a wavelength of 488 nm by a two-beam interference method to perform photopolymerization. The obtained liquid crystal optical element showed a blue reflection state when no voltage was applied. The reflectance of light having a wavelength of 488 nm was measured. The light reflectance decreased as the applied voltage increased. The drive voltage V ₁₀ is 27V
Met. The liquid crystal optical element has a charge holding ratio of 20.
At 92 ° C.

Example 3 In a liquid crystal cell having a gap of 5 μm composed of a glass substrate with ITO and a light-absorbing substrate with ITO, UV3000 (manufactured by Daikin), a precursor of a polymer resin, dielectric anisotropy Is a positive nematic liquid crystal E31LV (manufactured by Merck), a coumarin-based dye 6- (acryloyloxymethyl) -3- (2′-benzthiazolyl) -7-N, N-
A mixed solution of diethylaminocoumarin and a polymerization initiator benzoin methyl ether was injected under reduced pressure. The liquid crystal cell was irradiated with an argon laser having a wavelength of 488 nm at 25 ° C. by a two-beam interference method. The obtained liquid crystal optical element showed a blue reflection state when no voltage was applied. 100H for this element
An AC voltage of z was applied, and the reflectance of light having a wavelength of 488 nm was measured. When an AC voltage of 100 Hz was applied, the reflected light decreased. Driving voltage V ₁₀ was 18V.

Example 4 In a liquid crystal cell having a gap of 5 μm composed of a glass substrate with ITO and a light-absorbing substrate with ITO, UV3000 (manufactured by Daikin), a precursor of a polymer resin, and dielectric anisotropy Is a positive nematic liquid crystal RDP40957 (manufactured by Roddick), a coumarin-based dye 6- (acryloyloxymethyl) -3- (2′-benzthiazolyl) -7-N,
A mixed solution of N-diethylaminocoumarin and a polymerization initiator benzoin methyl ether was injected under reduced pressure. The liquid crystal cell was irradiated with an argon laser having a wavelength of 488 nm at 25 ° C. by a two-beam interference method. The obtained liquid crystal optical element showed a blue reflection state when no voltage was applied. 10
An AC voltage of 0 Hz was applied, and the reflectance of light having a wavelength of 488 nm was measured. When an AC voltage of 100 Hz was applied, the reflected light decreased. Driving voltage V ₁₀ was 25V. Also,
The charge retention of this liquid crystal optical element was 94% at 20 ° C.

Comparative Example 1 4- (dicyanomethylene) -2-methyl as a pigment material
Using 6- (p-dimethylaminostyryl) 4H-pyran
Liquid crystal optical element under the same conditions as in Example 1 except that
A device was prepared and the electro-optical characteristics were measured. This liquid crystal optical element
Drive voltage V _TenWas 23V.

Comparative Example 2 A liquid crystal optical element was prepared under the same conditions as in Example 2 except that 4- (dicyanomethylene) -2-methyl 6- (p-dimethylaminostyryl) 4H-pyran was used as a dye material. It was fabricated and its electro-optical characteristics were measured. Driving voltage V ₁₀ of the liquid crystal optical element was 31V. The charge retention of this liquid crystal optical element was 88% at 20 ° C.

Comparative Example 3 3- (2'-benzthiazolyl) -7-
Except for using N, N-diethylaminocoumarin, a liquid crystal optical element was prepared under the same conditions as in Example 3 and the electro-optical characteristics were measured. Driving voltage V ₁₀ of the liquid crystal optical element was 22V.

Comparative Example 4 3- (2'-benzthiazolyl) -7-
Except for using N, N-diethylaminocoumarin, a liquid crystal optical element was prepared under the same conditions as in Example 2 and the electro-optical characteristics were measured. Driving voltage V ₁₀ of the liquid crystal optical element was 28V. The charge retention of this liquid crystal optical element was 87% at 20 ° C.

[0038]

As described in detail above, according to the present invention, a photopolymerizable group is introduced into a dye material, copolymerized with a precursor of a polymer resin, and the dye material is fixed in the polymer resin. As a result, the driving voltage and charge retention of a liquid crystal optical element composed of a polymer resin, a dye material, and a liquid crystal material are improved, and the element can display characters, graphics, and the like. It can be suitably used for an apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a liquid crystal optical element of the present invention.

FIG. 2 is a diagram showing a state of irradiation with laser light when a liquid crystal optical element of the present invention is manufactured.

FIG. 3 is a diagram illustrating an example of a relationship between a light reflectance and an applied voltage of the liquid crystal optical element of the present invention.

FIG. 4 is a diagram illustrating another example of the relationship between the light reflectance and the applied voltage of the liquid crystal optical element of the present invention.

FIG. 5 is a diagram illustrating an example of a relationship between a charge retention rate and a temperature of the liquid crystal optical element of the present invention.

FIG. 6 is a diagram illustrating an example of a relationship between light reflectance and applied voltage of a conventional liquid crystal optical element.

FIG. 7 is a diagram illustrating another example of the relationship between the light reflectance and the applied voltage of a conventional liquid crystal optical element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Transparent electrode layer 3 Liquid crystal droplet 4 Polymer resin 5 Light absorption substrate 6 Incident light 7 Reflected light 8 AC power supply 9 Liquid crystal material, precursor of polymer resin, photopolymerization initiator,
Mixed solution of dye material 10 Laser light 1 11 Laser light 2

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuharu Onishi 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Masaharu Sato 5-7-1 Shiba, Minato-ku, Tokyo Japan Inside Electric Co., Ltd.

Claims (10)

[Claims] 1. A liquid crystal optical element in which a light modulating layer made of a polymer resin and a liquid crystal material is sandwiched between a transparent substrate having an electrode layer and a light absorbing substrate having an electrode layer. Are fixed and contained, and the liquid crystal material is regularly arranged in a droplet form. 2. The liquid crystal optical element according to claim 1, wherein the fixation of the dye material in the polymer resin is performed by photopolymerization of a precursor of the polymer resin and the dye material. 3. The liquid crystal optical element according to claim 1, wherein the photopolymerizable group of the dye material is a (meth) acryloyl group. 4. The liquid crystal optical element according to claim 1, wherein the dye material has a light absorption characteristic in a visible light region. 5. The liquid crystal optical element according to claim 1, wherein the dye material is a mixture of two or more dye materials having different light absorption wavelengths. 6. The liquid crystal optical element according to claim 1, wherein the dye material is a coumarin dye derivative. 7. The liquid crystal optical element according to claim 1, wherein the dye material is a styryl dye derivative. 8. The liquid crystal optical element according to claim 1, wherein the precursor of the polymer resin has a (meth) acryloyl group. 9. The liquid crystal optical element according to claim 1, wherein the ordinary light refractive index of the liquid crystal material matches the refractive index of the polymer resin. 10. The liquid crystal optical element according to claim 1, wherein the liquid crystal optical element is in a state of selectively reflecting visible light when no voltage is applied and in a light absorbing state when voltage is applied.