JPH08160386A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To obtain liquid crystal display device which is improved in brightness and contrast, is suitable for saving of energy and has a good housing property by holding a light controllable layer contg. a liquid crystal material and a transparent solid material between transparent substrates having transparent electrode layers and providing the device with a solar battery behind the device. CONSTITUTION: This light scattering liquid crystal device 1 is formed by holding the light controllable layer contg. the liquid crystal material, such as 4-substd. benzoic acid 4'-substd. phenyl ester, etc., and the transparent solid material, such as photosetting resin, obtd. by polymerizing a high polymer forming monomer or oligomer between two sheets of the transparent substrates having the transparent electrode layers. The light scattering liquid crystal display device 1 is provided with a solar battery plate 2 and a driving circuit 3 behind the device. The incident light on the light scattering liquid crystal device 1 is divided into forward scattered light and backward scattered light by the scattering state of the liquid crystal device. The forward scattering light quantity depends on the scattering characteristics of the light scattering liquid crystal display device 1, usually arrives at the solar battery plate 2 in a range of 50 to 90% and a part thereof is reflected and is added to the backward scattered light obtd. by the light scattering type liquid crystal display device 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device which is bright and has high contrast, is suitable for energy saving, and has a good storability. The liquid crystal display device of the present invention electrically displays the liquid crystal display with high speed response. By switching between, it is used as various display devices that require a bright screen, such as an advertising board, a decorative display board, and a sign board.

[0002]

2. Description of the Related Art Conventionally, liquid crystal devices used in liquid crystal display devices have been put to practical use as TN (twisted nematic) type using nematic liquid crystal and STN (super twisted nematic) type. . Also, a liquid crystal device using a ferroelectric liquid crystal has been proposed. Since these require a polarizing plate, it is impossible to provide a solar cell plate behind the liquid crystal device as in the present invention.

A liquid crystal device in which liquid crystal droplets are dispersed in a polymer is known as a liquid crystal device which does not require a polarizing plate. Japanese Patent Publication No. 58-501631, Japanese Patent No. 44350.
No. 47 discloses gelatin as an encapsulating substance,
Gum arabic, polyvinyl alcohol, and the like have been proposed, and in addition to these, JP-A-61-502128 and JP-A-62-2231 are proposed.

Further, in order to enable the low-voltage drivability, high contrast, and time-division drivability, which are important characteristics required for the practical use of the liquid crystal device as described above, US Pat. No. 5,304,323. Description, JP-A-1-198725
The publication discloses a liquid crystal device having a structure in which a liquid crystal material forms a continuous layer and a polymer substance is distributed in a three-dimensional network in the continuous layer.

[0005]

The light-scattering type liquid crystal device as described above is considered to be used for a large-sized display device or a portable display device. In this case, there have been few proposals to use a solar cell together. On the other hand, in a TN type liquid crystal display that also uses a solar cell, a polarizing plate is required, so that the display device is individually mounted. In addition, in the medium-sized and large-sized STN type liquid crystal display, there is a problem that the solar cell plate becomes large because it is necessary to increase the power supply, and a display device having a solar cell has not been put into practical use.

The problem to be solved by the present invention is to provide a display device having a solar cell, and thereby to provide a liquid crystal display device suitable for energy saving and good in storability. Another object of the present invention is to provide a liquid crystal display device having an unexpected improvement effect on display characteristics such as brightness and contrast.

[0007]

To solve the above problems, the present invention has a light control layer sandwiched between two transparent substrates having a transparent electrode layer, and the light control layer is a liquid crystal. Provided is a liquid crystal display device comprising a solar cell plate behind a light-scattering liquid crystal device containing a material and a transparent solid substance.

The substrate of the light-scattering liquid crystal device used in the present invention may be a rigid material such as glass or a flexible material such as a plastic film. And
Two substrates are opposed to each other and are separated by an appropriate distance.

In order to control the thickness of the light control layer, it is desirable to interpose a spacer for maintaining a gap between the two substrates, as in a commonly known liquid crystal device. As such spacers, for example, those for various liquid crystal cells such as mylar, alumina, rod-type glass fiber, glass beads, polymer beads and the like can be used.

By providing a refractive index layer having a refractive index different from that of the substrate on the surface of the substrate corresponding to the display surface of the substrate, the effect of the present invention can be made preferable.

Further, the refractive index of the gap layer formed by the liquid crystal device and the solar cell plate is the refractive index of the substrate surface of the liquid crystal device facing the solar cell plate side and / or the solar cell plate surface facing the liquid crystal device side. It is more preferable to design the refractive index to be smaller than the refractive index of. For this purpose, the interstitial layer is, for example,
It may be formed with an adhesive of an organic material or an inorganic material,
It is also possible to simply provide an air layer. The thickness of the gap layer is preferably in the range of 4 μm to 2 mm, more preferably thin.

This substrate may be provided with electrodes for transmitting and scattering light appropriately or entirely according to the purpose, or at least one substrate may have a signal line, a pixel electrode and a pixel electrode. It can have a non-linear element or an active element formed for each.

The liquid crystal material of the light-scattering type liquid crystal device used in the present invention does not necessarily need to be a single liquid crystal compound, and may include two or more kinds of liquid crystal compounds and substances other than liquid crystal compounds. It may be a mixture of compounds, which is generally recognized as a liquid crystal material in this technical field, and one having a positive dielectric anisotropy is preferable. Since the liquid crystal device of the present invention has a particularly excellent light utilization rate, the refractive index anisotropy Δn of the liquid crystal material used is 0.
A range of 10 to 0.30, which is wider than the conventional range, can also be used.

The liquid crystal material used in the present invention does not need to be a single liquid crystal compound, and may be a mixture containing two or more kinds of liquid crystal compounds or substances other than the liquid crystal compounds. Any material that is generally recognized as a liquid crystal material in this technical field is preferable, and one having a positive dielectric anisotropy is preferable, and if the manufactured liquid crystal device is a liquid crystal that can obtain good characteristics. good.

The liquid crystal used is preferably a nematic liquid crystal, a smectic liquid crystal or a cholesteric liquid crystal, particularly preferably a nematic liquid crystal. In order to improve its performance, cholesteric liquid crystals, chiral nematic liquid crystals, chiral smectic liquid crystals, chiral compounds and 2
A color dye or the like may be appropriately contained.

The liquid crystal material used in the present invention is preferably a blended composition comprising one or more compounds selected from the compound group shown below, and the characteristics of the liquid crystal material, that is, the phase of the isotropic liquid and the liquid crystal. For the purpose of improving the transition temperature, melting point, viscosity, Δn, Δε, solubility with a polymerizable composition and the like, they can be appropriately selected and blended for use.

Examples of the liquid crystal material include 4-substituted benzoic acid 4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-substituted biphenyl ester, 4- (4-substituted cyclohexanecarbonyloxy)
Benzoic acid 4'-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4'-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4'-substituted cyclohexyl ester, 4-substituted 4'-substituted Biphenyl, 4-substituted phenyl-4'-substituted cyclohexane,
4-substituted 4 ″ -substituted terphenyl, 4-substituted biphenyl 4′-substituted cyclohexane, 2- (4-substituted phenyl)
-5-substituted pyrimidine etc. can be mentioned.

The proportion of the liquid crystal material in the light control layer is 60% by weight.
The above is preferable, and the range of 70 to 90% by weight is particularly preferable. (Hereinafter, "%" means "% by weight")

The light control layer of the light-scattering liquid crystal device used in the present invention may be, for example, a nematic liquid crystal material microencapsulated as described in JP-A-58-501631. A nematic liquid crystal material as described in JP-A-502128 may be dispersed in a synthetic resin matrix in a droplet form. They are,
The principle is that light scattering occurs due to the mismatch between the refractive index of the synthetic resin and the refractive index of the nematic liquid crystal in the state where no electric field is applied, and the two refractive indexes match in the state where an electric field is applied, resulting in a light transmitting state.

The most preferable light control layer is JP-A-1-198.
As described in Japanese Laid-Open Patent Publication No. 725/725, the liquid crystal material forms a continuous layer, and in this continuous layer, a transparent solid substance having a three-dimensional network is formed. In this case, the proportion of the liquid crystal material in the light control layer is preferably 60% by weight or more, more specifically 70% by weight.
The range is preferably from 95 to 95% by weight, particularly preferably from 75 to 90% by weight. If the average diameter of the formed three-dimensional network structure is too large or too small as compared with the wavelength of light, the light scattering property tends to deteriorate, so the average diameter is 0.2 to 2 μm.
Is preferred. The layer thickness of the light control layer can be designed according to the purpose of use, but in order to obtain a sufficient contrast between the opacity due to light scattering and the light transmission achieved electrically, it is in the range of 2 to 20 μm. Is preferred.

As the transparent solid substance used in the present invention, a photocurable synthetic resin is suitable. A photo-curable resin obtained by polymerizing a polymer-forming monomer or oligomer is preferable as a polymer that gives a three-dimensional network structure. In order to obtain a light scattering type liquid crystal device having a lower driving voltage, it is more preferable to use a monofunctional monomer and a bifunctional monomer in combination.

As a method of forming a three-dimensional network structure by the transparent solid substance of the light control layer, for example, (a) a liquid crystal material and (b) a polymer-forming monomer or oligomer sandwiched between two substrates. And a method of polymerizing the photopolymerizable composition by irradiating an active ray while maintaining the light control layer forming material containing a polymerization initiator in an isotropic liquid state.

As the polymer-forming monomer, for example, styrene, chlorostyrene, α-methylstyrene, divinylbenzene; as a substituent, methyl, ethyl, propyl, butyl, amyl, 2-ethylhexyl, octyl,
Nonyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl,
Acrylate, methacrylate or fumarate having a group such as 3-chloro-2-hydroxypropyl, dimethylaminoethyl, diethylaminoethyl; ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexa Poly (meth) acrylates or poly (meth) acrylates such as methylene glycol, neopentyl glycol, trimethylolpropane, glycerin and pentaerythritol;
Vinyl acetate, vinyl butyrate or vinyl benzoate, acrylonitrile, cetyl vinyl ether, limonene, cyclohexene, diallyl phthalate, 2-, 3- or 4-vinyl pyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethyl acrylamide or N-hydroxyethyl methacrylamide and alkyl ether compounds thereof; di- or tri (meth) acrylate of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane; to 1 mol of neopentyl glycol Di (meth) diol obtained by adding 2 moles or more of ethylene oxide or propylene oxide
Acrylate; Reaction product of 1 mol of 2-hydroxyethyl (meth) acrylate and 1 mol of phenyl isocyanate or n-butyl isocyanate; Poly (meth) acrylate of dipentaerythritol; Poly (tris- (hydroxyethyl) -isocyanuric acid poly ( (Meth) acrylate; poly (meth) acrylate of tris- (hydroxyethyl) -phosphoric acid; di- (hydroxyethyl)-
Dicyclopentadiene mono (meth) acrylate or di (meth) acrylate; pivalate neopentyl glycol diacrylate; caprolactone modified hydroxypivalate neopentyl glycol diacrylate; linear aliphatic diacrylate; polyolefin modified neopentyl glycol di An acrylate etc. can be mentioned.

The polymer-forming oligomers include, for example,
Epoxy (meth) acrylate, polyester (meth)
Various acrylate oligomers such as acrylate, polyurethane (meth) acrylate, and polyether (meth) acrylate can be used.

As the polymerization initiator, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Geigy). Irgacure 184 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-
On (Merck "Darocur 1116"), benzyl dimethyl ketal (Ciba Geigy "Irgacure 651"), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 (Ciba)・ Geigy's "Irgacure 907"), 2,4-diethylthioxanthone (Nippon Kayaku's "Kayacure DET"
X)) and ethyl p-dimethylaminobenzoate (“Kayacure EPA” manufactured by Nippon Kayaku Co., Ltd.), isopropyl thioxanthone (“Cantcure ITX” manufactured by Ward Prekinsop) and ethyl p-dimethylaminobenzoate. And a mixture thereof.

The proportion of the polymerization initiator used is preferably 0.1 to 10.0% of the total amount of the polymerizable compounds.

The average distance between the meshes of the three-dimensional mesh structure formed of the transparent solid substance is preferably in the range of 0.2 to 5 μm. In addition, the layer thickness of the layer having a transparent solid substance is set to 1 to obtain a sufficient contrast between the opacity due to light scattering and the transparency achieved electrically or thermally depending on the purpose of use. The range of 30 μm is preferable.

The energy for polymerization is ultraviolet light, visible light,
An electron beam or the like can be used, but ultraviolet rays are preferable. In the polymerization of the polymerizable composition by ultraviolet irradiation in the liquid crystal material, the light irradiation intensity and the irradiation amount also require a certain intensity or more, which depends on the reactivity of the polymerizable composition and the type and concentration of the polymerization initiator. Depending on the light intensity, it is possible to form a three-dimensional mesh and uniformize the size of the mesh by selecting an appropriate light intensity. More preferably, as the method of irradiating light, uniform irradiation in time and plane allows the polymerizable composition interposed between the substrates to be instantaneously irradiated with strong light to proceed with the polymerization. It is effective in making the size of the uniform. That is, a uniform three-dimensional network polymer can be realized in the liquid crystal continuous layer by irradiating with pulsed light at an appropriate light intensity.

The present invention can be applied to other light-scattering type liquid crystal devices, for example, to a nematic-cholesteric phase transition type or a dynamic scattering mode.

The solar cell plate used in the present invention may be a germanium solar cell or a silicon solar cell, and a single crystal, polycrystal or amorphous silicon solar cell is practical. Some amorphous silicon solar cells allow light to pass therethrough, and some do not allow light to pass therethrough, but according to the present invention, those can be used. As such a solar cell plate, for example,
"AM-1400", "AM-180" manufactured by Sanyo Electric Co., Ltd.
0 "," AM-5600 ", and" AMP-D10 "series.

[0031]

The function will be described in detail below with reference to the drawings. FIG. 1 is a schematic perspective view showing the configuration of an example of the liquid crystal display device of the present invention. Here, 1 is a light scattering type liquid crystal device, 2 is a solar cell plate which does not transmit light, and 3 is a drive circuit. When a solar cell plate that transmits light is used, a light absorbing plate, a background plate, a transparent film, a reflecting plate, or the like may be arranged behind this, or may not be used. As a matter of course, the drive circuit 3 can be arranged at a position other than the position shown in FIG. 1 depending on the application. FIG. 2 shows a cross-sectional view of the configuration of the liquid crystal display device of FIG. Here, 4 is a gap layer, 5 is incident ambient light, 6 is a pixel of the light scattering liquid crystal device in a transparent state, and 7 is a pixel of the light scattering liquid crystal device 1 in a scattering state.

The most important thing in the present invention is that the function of the solar cell is basically maintained in the configuration of FIG. Light incident on the light-scattering liquid crystal device 1 according to the present invention is divided into forward scattered light and back scattered light depending on the scattering state of the liquid crystal device. The amount of forward scattered light depends on the scattering characteristics of the light-scattering type liquid crystal device, and it has been clarified by the present inventors that it is usually in the range of 50 to 90% (1993 SID International Symposium Dige).
st of Technical Paper, Vol. 26, p. 75). The forward scattered light passes through the gap layer 4 and reaches the solar cell plate 2. Even if the light-scattering liquid crystal device 1 is in a scattering state on the entire surface, the forward scattered light reaches the solar cell plate 2. In the above-described AM-1400 series, for example, the solar cell plate 2 can take out a predetermined electric power as long as the illuminance is 50 to 200 Lx or more. As a general indoor lighting environment, for example, according to occupational safety and health regulations, 70 to 300
It is defined as Lx or more. Therefore, the liquid crystal display device of the present invention can be widely used not only outdoors but also indoors by designing these things according to the application.

On the other hand, in the TN type or STN type liquid crystal display, since a polarizing plate is required, the light transmittance is as low as 5 to 30% even in the so-called white display. Becomes 1% or less, and the function of the solar cell is stopped. Further, in the medium-sized large-sized liquid crystal display, a large solar cell plate is required due to the need for high power supply, whereas a display device in which the solar cell plate 2 can occupy the entire effective display surface of the light-scattering liquid crystal device 1. It was possible to fabricate, and it became possible to obtain higher power. Therefore, the liquid crystal display device of the present invention is a liquid crystal display device that does not require a portion occupied by a solar cell and has good storability, and is preferable for a portable or large-sized display device. An example of such a display device is shown in FIG.

The display in the liquid crystal display device of the present invention is visually recognized as follows. In FIG. 1, for example, when the scattering state 7 is used as the background color of the white background, the pixel selected according to the desired character diagram is displayed as the transparent state 6. The pixel in the transparent state 6 directly displays the color of the solar cell plate 2, usually dark brown or dark blue. Therefore, as a display, a dark brown or dark blue character map is visually recognized on a white background. When displaying black and white in a conventional light scattering type liquid crystal device, a light absorbing plate is used behind. However, according to the liquid crystal display device of the present invention, the solar cell plate 2 also serves as a light absorbing plate. Therefore, it is possible to provide a simpler reflective display device.

When the solar cell plate 2 that transmits light is used, both a transmissive display device and a reflective display device can be manufactured. The transmissive display device may be produced by simply stacking the light-scattering liquid crystal device 1 and the solar cell plate 2,
As shown in FIG. 4, the light scattering type liquid crystal device 1 may be sandwiched between two sets of solar cell plates 2. In this case, for example, the scattering state 7
Can be displayed as a transparent state 6 with a white background color. Further, for example, as shown in FIG.
Further, by providing a transparent color layer or film 8 or the like, the white background in the scattering state 7 can be changed to a desired background color.

The reflective display device can be manufactured by disposing the background plate 9 behind the solar cell plate 2 as shown in FIG. In this case, for example, the scattering state 7 can be a white background color, and the character diagram formed by the pixels in the transparent state 6 can be displayed in the color of the background plate 9. That is, according to the present invention, a display device can be manufactured with a color scheme that does not depend on the solar cell plate 2.

The present invention is characterized by the presence of the solar cell plate 2.
An unexpected improvement effect was found in the scattering characteristics of the light scattering type liquid crystal device 1. That is, part of the forward scattered light obtained by the light-scattering liquid crystal device 1 is reflected by the solar cell plate 2, and this is added to the back-scattered light obtained by the light-scattering liquid crystal device 1 to obtain a brighter white background. You can Therefore, the display device of the present invention has a display characteristic of brighter and improved contrast.

This effect is obtained by adjusting the refractive index of the gap layer 4 to the refractive index of the substrate surface of the light-scattering liquid crystal device 1 facing the solar cell plate 2 side and / or the solar cell facing the light-scattering liquid crystal device 1 side. It is preferable to design the refractive index smaller than that of the surface of the plate 2. For example, it may simply be an air layer. However, in this case, specular reflection light of ambient light may appear on the surface of the solar cell plate 2. This phenomenon can be reduced by adjusting the refractive index of the gap layer between the light scattering liquid crystal device and the solar cell plate. Therefore, it is preferable to specify the refractive index of the gap layer 4 in the range of 1 to 1.5.

[0039]

EXAMPLES The present invention will be described more specifically below by showing examples of the present invention. However, the invention is not limited to these examples.

In the following examples and comparative examples,
The characteristic values of T ₀ and T ₁₀₀ of the light scattering type liquid crystal device have the following symbols and contents. With the device removed from the photometric state, the light transmittance when the light source is on is 100%, the light transmittance when the light is off is 0%, the light transmittance of the device when no voltage is applied is T ₀ , and the applied voltage is The light transmittance saturated with the increase of T ₁₀₀ is T ₁₀₀ . V ₉₀ is the light transmittance (T ₀ ) of the device when no voltage is applied and is 0%, and the light transmittance (T ₁₀₀ ) is 100 when the light transmittance does not change as the applied voltage increases. %, The voltage is such that the light transmittance is 90%.

Example 1 <Liquid crystal material>"PN-011" (manufactured by Rodick) 80% by weight <Polymer-forming compound>"HX-220" 13.8% by weight (caprolactone modified by Nippon Kayaku Co., Ltd.) Hydroxypivalic acid ester neopentyl glycol diacrylate) 4- (trans-4- (3,4-difluorophenyl) cyclohexyl) cyclohexyl acrylate 6.0% by weight <Polymerization initiator> 2-hydroxy-2-methyl-1- A light control layer forming material of a uniform solution in which 0.2% by weight of phenylpropan-1-one was mixed was prepared. This uniform solution was vacuum-injected into an empty cell having a 10 μm gap between two glass substrates (55.0 mm × 29.3 mm) having ITO electrode layers on the entire surface at a temperature 10 ° C. higher than the transition temperature of the uniform solution. . While maintaining this at a temperature of 37.5 ° C., it was passed through a metal halide lamp (100 W / cm ² ) under ultraviolet light at a speed of 3.5 m / min to obtain a light-scattering liquid crystal device.

Regarding the obtained light-scattering liquid crystal device,
When a cross section of the cured product formed between the substrates was observed using a scanning electron microscope, a transparent solid substance having a three-dimensional network structure composed of a polymer was observed.

Further, in this light-scattering type liquid crystal device, the driving voltage V ₉₀ is 4.75 V and the transmissivity T ₀ at the time of OFF is 3.7.
%, And the transmittance T ₁₀₀ at the time of ON was 82.4%.

Next, this light scattering type liquid crystal device and AM-
5703 (manufactured by Sanyo Electric Co., Ltd.) solar cell plates were overlaid to prepare a liquid crystal display device of the present invention. As an IC element, "T
C4043BP "(manufactured by Toshiba Corporation) or" HD14070B
A driving circuit using "P" (manufactured by Hitachi Ltd.) was manufactured and an operation was tried. When installed at an illuminance of 300 Lx, white display and dark blue display were repeated.

Example 2 A light-scattering liquid crystal device was prepared in the same manner as in Example 1 except that two glass substrates each having an ITO electrode layer patterned into segments capable of expressing 6-digit numbers were used. A liquid crystal display device of the present invention was obtained. When it was installed at an illuminance of 600 Lx, dark blue navy 8 characters were sequentially displayed up to 6 digits on a white background, and then the entire surface became a white background periodically. This display was visible with high contrast in a bright and wide viewing angle.

[0046]

The liquid crystal display device of the present invention can accommodate a solar cell which is bright, has high contrast, and is suitable for energy saving. Further, since the liquid crystal display device of the present invention can switch its display electrically with a high-speed response, it can be used as various display devices such as an advertising board, a decorative display board, and a sign board which require a bright screen.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a liquid crystal display device of the present invention including a light-scattering liquid crystal device and a solar cell plate.

FIG. 2 is a schematic cross-sectional view of a liquid crystal display device of the present invention including a light scattering type liquid crystal device and a solar cell plate.

FIG. 3 is a front view of a portable calculator to which the liquid crystal display device of the present invention is applied.

FIG. 4 is a schematic cross-sectional view of a liquid crystal display device of the present invention configured by sandwiching a light-scattering liquid crystal device between two sets of solar cell plates.

FIG. 5 is a schematic cross-sectional view when the liquid crystal display device of the present invention is configured as a reflective display.

[Explanation of symbols]

 1 Light-scattering type liquid crystal device 2 Solar cell plate 3 Driving circuit 4 Gap layer 5 Ambient light 6 Pixels in transparent state 7 Pixels in scattering state 8 Transparent color film 9 Background plate

Claims (4)

[Claims] 1. A light-scattering type liquid crystal device having a light control layer sandwiched between two transparent substrates having a transparent electrode layer, the light control layer containing a liquid crystal material and a transparent solid substance. A liquid crystal display device having a solar cell plate behind it. 2. The refractive index of a gap layer formed between the liquid crystal device and the solar cell plate is a refractive index of a substrate on the surface of the liquid crystal device facing the solar cell plate side and / or a surface facing the liquid crystal device side. The liquid crystal display device according to claim 1, wherein the refractive index is smaller than that of the surface of the solar cell plate. 3. The liquid crystal display device according to claim 1, wherein an effective display surface of the liquid crystal device is occupied by the solar cell plate. 4. The light control layer comprises a continuous layer of a liquid crystal material and a transparent solid substance having a three-dimensional network structure formed in the continuous layer. The described liquid crystal device.