JP3047966B2 - Liquid crystal optical element and manufacturing method thereof - Google Patents

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 is in an absorbing state when no voltage is applied and is in a selective reflection state when a voltage is applied.
It is used for a display device that displays characters, figures, and the like.

[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 that does not require a backlight as a liquid crystal device, that is, a reflective liquid crystal device. 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 Laid-Open 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 this reflection type liquid crystal optical element has bistability, it is driven by a simple matrix. In this liquid crystal optical element, a liquid crystal optical element having different selective reflection wavelengths can be manufactured by setting the distance between liquid crystal droplets. Can be realized. However, since this liquid crystal optical element reflects one of the left and right circularly polarized lights, there is a problem that the reflection efficiency is low.

On the other hand, Japanese Patent Publication No. 3-52843 discloses a transmission / scattering type liquid crystal optical element in which liquid crystal is microencapsulated and dispersed in a polymer material. This disclosed technology has advantages in that light utilization efficiency is high because a polarizing plate is not required, and that it can be driven by an active element such as a TFT (thin film transistor) or MIM. As a technique similar to the disclosed technique, a transmission / absorption type liquid crystal optical element in which a dichroic dye is dissolved in a liquid crystal, that is, a so-called guest-host mode is disclosed in JP-A-62-50278.
No. 0 report. Further, Japanese Patent Application Laid-Open No. 9-804
No. 01 discloses a technique of laminating a liquid crystal microcapsule layer in which a dichroic dye is dissolved in a liquid crystal on a reflector via an electrode layer. Further, JP-A-5-134
266 discloses a reflective liquid crystal element composed of 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. When no voltage is applied, the liquid crystal molecules in the liquid crystal droplets are randomly oriented, and a difference in refractive index from the polymer material occurs. Light is selectively reflected by the refractive index difference and the period of the liquid crystal droplet. When a voltage is applied to the liquid crystal optical element, the difference in the refractive index between the polymer material and the liquid crystal droplet becomes smaller, and the intensity of the selectively reflected light decreases.

[0004]

The holographic polymer-dispersed liquid crystal device (HPDLC) has a multicolor method for spatial division of red, green and blue (planar arrangement) or red, green and blue.
It has been reported that three monochromatic panels respectively reflecting green and blue are bonded together (JP-A-6-29495).
No. 2). The space division type has a problem that the light use efficiency is reduced to 1/3 of that of the single color panel because the pixel is divided into three. When three panels are combined, the light use efficiency is three times as large as the space division. There has been a problem that parallax due to the thickness of the substrate occurs.

Japanese Patent Application Laid-Open No. 9-80401 discloses a guest-host mode liquid crystal optical element in which three layers are stacked without using a substrate between liquid crystal microcapsule layers. As a process of manufacturing a layered structure of layers, a process of manufacturing conductive columns for applying a voltage to each pixel electrode, a resist process for each liquid crystal microcapsule layer to electrically connect each pixel electrode and the conductive column There is a problem that a process is required and the manufacturing process is complicated.

An object of the present invention is to provide a high-resolution image without parallax.
An object of the present invention is to provide a holographic polymer-dispersed liquid crystal optical element whose manufacturing process is relatively simple.

[0007]

Means for Solving the Problems The present invention is as follows. 1. Dimming layers composed of a polymer resin and a liquid crystal material are alternately stacked on the light absorbing substrate and the electrode layers, and each dimming layer is sandwiched between the electrode layers. Droplets are regularly arranged in the polymer resin, and at least one opening is provided for each display pixel in the liquid crystal optical element, which is characterized by selectively reflecting light in the visible light region. A liquid crystal optical element comprising: 2. 2. The liquid crystal optical element according to the above item 1, wherein the laminated light control layer is separated for each display pixel. 3. 3. The liquid crystal optical element according to the above 1 or 2, further comprising an extraction electrode from each electrode layer on a side surface of each display pixel. 4. 3. The liquid crystal optical element according to the above item 1 or 2, wherein the angle formed between the plane of the light absorbing substrate and the side surface of the opening forming the extraction electrode is less than 90 degrees. 5. 3. The liquid crystal optical element according to the above 1 or 2, wherein three light control layers are laminated on the light absorbing substrate, and reflected light of each light control layer is red, green, and blue, respectively. 6. The ordinary light refractive index of the liquid crystal material matches the refractive index of the polymer resin, and the dimming layer is in a light reflecting state when no voltage is applied,
6. The liquid crystal optical element according to any one of the above items 1 to 5, wherein the intensity of the reflected light decreases as the applied voltage increases. 7. 5. The light control layer according to the above item 5, wherein the thickness of the light control layer that reflects green is smaller than the film thickness of the light control layer that reflects blue and red.
The liquid crystal optical element according to the above. 8. 2. The liquid crystal optical element according to the above item 1, wherein at least one electrode layer is made of a conductive polymer material. 9. 9. The liquid crystal optical element according to any one of the above 1 to 8, wherein a protective film having a thickness less than the thickness of the light control layer is provided between the light control layer and the electrode layer. 10. 10. The liquid crystal optical element according to any one of the above items 1 to 9, wherein one electrode layer is electrically connected to the counter electrode, and the other electrode layer is electrically connected to the source electrode of the thin film transistor. 11. The electrode layer between the light absorbing substrate and the light modulating layer and the electrode layer between each light modulating layer are electrically connected to the source electrode of the thin film transistor installed on the light absorbing substrate, and the electrode layer on the outermost surface is electrically connected to the counter electrode. 11. The liquid crystal optical element according to the above item 10, wherein the liquid crystal optical element is connected to the optical element. 12. The electrode layer between the light absorbing substrate and the light modulating layer and the electrode layer between each light modulating layer are electrically connected to the source electrode of the thin film transistor installed on the light absorbing substrate, and the electrode layer on the outermost surface is on the light absorbing substrate. 12. The liquid crystal optical element according to the above item 11, wherein the liquid crystal optical element is electrically connected to a counter electrode formed in the element. 13. A step of forming an electrode layer on the light absorbing substrate, a step of alternately laminating the dimming layer and the electrode layer on the light absorbing substrate with the electrode layer, and a step from the outermost surface electrode layer to the light absorbing substrate for each display pixel. A method for manufacturing a liquid crystal optical element, comprising: a step of forming an opening to reach; and a step of forming an extraction electrode on a side surface of each display pixel.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The light absorbing substrate used in the present invention may be an inorganic material or an organic material as long as it is made of a material that absorbs visible light. The light absorption intensity or light absorption wavelength can be arbitrarily changed according to the target device characteristics. The light-absorbing material may be formed by coating a light-absorbing material on a transparent substrate such as glass or plastic, or by laminating a light-absorbing substrate on a transparent substrate. At this time, the light absorbing material is preferably on the light control layer side, but is not limited thereto. When bonding to the opposite side of the light control layer, a light absorbing substrate may be bonded on the transparent substrate after the light control layer is formed.

The light modulating layer comprising the polymer resin and the liquid crystal material of the present invention is obtained by irradiating a solution containing at least a precursor compound of the polymer resin, a liquid crystal material and a polymerization initiator with light to form a precursor of the polymer resin. The compound can be produced by curing, ie, polymerizing, a polymer resin. In addition, the structure in which the liquid crystal material in the polymer resin is regularly arranged in the form of drops should be manufactured by curing the precursor compound of the polymer resin by a two-beam interference method using laser light in a nitrogen atmosphere. Can be. The selective reflection wavelength and its intensity can be adjusted by the distance between the liquid crystal droplets and the difference in the refractive index between the polymer resin and the liquid crystal material. For full-color display, a dimming layer that selectively reflects red on a light-absorbing substrate, a dimming layer that selectively reflects green,
Three types of light control layers, which selectively reflect blue light, are laminated.
The order of lamination may be any. The thickness of each light control layer is 5
About 15 μm is desirable. Further, the thickness of each light control layer does not need to be the same. Preferably, the thickness of the light control layer that selectively reflects red and the light control layer that selectively reflects blue is greater than the thickness of the light control layer that selectively reflects green.

The refractive index of the polymer resin of the present invention, that is, the precursor compound of the polymer resin, is set at or near the ordinary light refractive index (n _O ) of the liquid crystal material after photocuring. The liquid crystal material in the liquid crystal droplets of the light control layer is in a random state when no voltage is applied, so the light control layer is caused by the difference between the refractive index of the polymer resin and the liquid crystal material when no voltage is applied and the distance between the liquid crystal droplets. And a selective reflection state of light is obtained. On the other hand, as the voltage applied to the light control layer increases, the difference in the refractive index between the polymer resin and the liquid crystal material decreases, and the selective reflection intensity decreases.

As the precursor compound of the polymer resin, a monomer or oligomer which is cured or polymerized by light irradiation, or a mixture of a monomer and an oligomer can be used. That is, any polymer precursor having an ordinary photopolymerizable group such as an acryloyl group, a methacryloyl group, and a vinyl group can be used. A plurality of photopolymerizable groups may be present in one molecule of the polymer precursor compound. Examples of the monomer include 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-dimethylaminoethyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, isobonyl acrylate, isodecyl acrylate, lauryl acrylate, morpholine acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, etc. Monofunctional acrylate compound, 2-ethylhexyl methacrylate, butylethyl methacrylate, butoxyethyl methacrylate, 2-cyanoethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, 2-hydroxypropyl methacrylate, 2-ethoxyethyl acrylate, N, N-diethylaminoethyl methacrylate, N, N-Jim Monofunctional methacrylates such as laminoethyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, isobonyl methacrylate, isodecyl methacrylate, lauryl methacrylate, morpholine methacrylate, phenoxyethyl methacrylate, and phenoxydiethylene glycol 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 diaclaire Polyfunctional acrylate compounds such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, urethane acrylate oligomer, diethylene glycol dimethacrylate , 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.

[0012] The precursor compound of the polymer resin includes a photopolymerization initiator for initiating polymerization by light irradiation, a photoinitiator which supplies protons to the photopolymerization initiator, and a photoinitiator which absorbs light and converts excitation energy to light. A dye sensitizer or the like that is transferred to the polymerization initiator can be added. However, when the photopolymerization initiator itself absorbs light used for photopolymerization, the dye sensitizer may not be added.

As the photopolymerization initiator, ordinary photopolymerization initiators such as acetophenone type, benzoin type, benzophenone type and thioxanthone type can be used. 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 photopolymerization initiator may be a solid or a liquid, but is desirably one that is dissolved or compatible with the liquid crystal in view of the uniformity of the device. The photopolymerization initiator concentration is preferably 30% by weight or less of the polymer resin precursor. If necessary, a photopolymerization initiation aid such as methyldiethanolamine and 4-dimethylaminobenzoic acid can be added. As the dye sensitizer in the present invention, coumarin dyes, rhodamine dyes, oxazine dyes, carbocyanine dyes, dicarbocyanine dyes, tricarbocyanine dyes, tetracarbocyanine dyes, pentacarbocyanine dyes, Oxonol dyes, styryl dyes, xanthene dyes, merocyanine dyes, rhodocyanine dyes,
Examples include porphyrin dyes and acridine dyes, but are not limited thereto. Any dye material can be used as long as it is excited by laser light to transfer energy to the start of photopolymerization and has photopolymerizability such as a vinyl group.

As a light beam used for photopolymerization of the precursor of the polymer resin, a visible laser beam 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, and laser light sources having different wavelengths are used. At this time, a light shielding film such as a photomask may be used.

The liquid crystal used in the liquid crystal optical element of the present invention is particularly preferably a nematic liquid crystal. As the nematic liquid crystal, any liquid crystal such as cyano-based, fluorine-based, and chlorine-based can be used. However, a fluorine-based liquid crystal having a high charge retention rate is required for active driving with an active element such as a thin film transistor (TFT). Is desirable. As the dielectric anisotropy of the liquid crystal, a positive dielectric anisotropy is preferable, but by changing the frequency, a two-frequency driving liquid crystal in which the dielectric anisotropy can take both positive and negative values, or Liquid crystals having a negative dielectric anisotropy may be used. Further, the size and interval of the liquid crystal droplets regularly present in the light control layer can be arbitrarily set according to the target reflected light wavelength. The ratio of the liquid crystal in the light control layer is desirably 20% by weight or more and 80% by weight or less. Outside this range, the regular arrangement of the liquid crystal droplets is not formed, and the reflectance of visible light decreases. If the amount of the liquid crystal material is too small, the driving voltage of the liquid crystal optical element becomes high.

As a material for the electrode layer used in the present invention, indium-tin-oxide (ITO) or a conductive polymer material can be used. The electrode layer formed on the light-absorbing substrate is not necessarily required to be transparent, but it is desirable that the other electrode layers, that is, the electrode layer between the light control layers and the outermost electrode layer are transparent. Further, the extraction electrode for applying a voltage to each electrode layer does not need to be transparent, and any conductive material such as a metal and a conductive polymer material may be used. When each dimming layer is driven by the thin film transistor, one electrode layer may be electrically connected to the counter electrode and the other electrode layer may be electrically connected to the source electrode of each thin film transistor. The electrode layer between the light absorbing substrate and the light modulating layer and the electrode layer between each light modulating layer are electrically connected to the source electrode of the thin film transistor provided on the light absorbing substrate, and the electrode layer on the outermost surface is formed. Is desirably a counter electrode provided on the light absorbing substrate. When the outermost electrode layer is used as a counter electrode, it is not always necessary to separate the outermost electrode layer for each display pixel. When the outermost electrode layer is electrically connected to the counter electrode formed on the light-absorbing substrate, the number of connection portions does not need to match the number of each display pixel, and may be one or more. As the conductive polymer material, polypyrrole, polythiophene, polyaniline, or the like can be used, and the conductivity may be adjusted by adding a dopant.

In the laminated dimming layer of the present invention, at least one opening is provided for each display pixel from the outermost electrode layer to the light absorbing substrate. This opening is provided for each display pixel,
That is, it is for forming an extraction electrode from each electrode layer on the side surface of the laminated light control layer, and the shape and size of the opening can be arbitrarily selected depending on the thickness of the light control layer, the number of layers, and the like.
The side surface of the opening for forming the extraction electrode may be parallel to the normal line of the light-absorbing substrate, but the light-absorbing substrate plane and the extraction electrode are formed so that the extraction electrode can be formed from above by sputtering or the like. It is desirable that the angle formed by the side surface of the opening to be formed is less than 90 degrees. Further, the light control layers stacked by the openings may be separated for each display pixel. At this time, the side surface on which the extraction electrode is formed may be parallel to the normal line of the light absorbing substrate, but the light absorption substrate plane and the extraction electrode are formed so that the extraction electrode can be formed by sputtering or the like from above. It is desirable that the angle formed by the side surface of the opening is less than 90 degrees.

In the present invention, as the light control layer, a protective film having a thickness less than the thickness of the light control layer can be provided between the light control layer and the electrode layer before the electrode layer is laminated. This protective film is mainly for preventing the light control layer from being damaged during the formation of the electrode layer, and the material and thickness depend on the material of the electrode layer to be used and the film forming conditions. It is preferable to have properties such as resistance to plasma, resistance to organic solvents, resistance to ultraviolet rays, and the like. The material may be an inorganic or organic material, but is preferably a material that does not significantly reduce the charge retention of the light control layer.

Further, in the present invention, a transparent surface protective layer may be formed on the light control layer laminated for protecting the device. This surface protective layer may be filled in the openings formed between the display pixels or when the display pixels are independent from each other, between the openings or between the pixels. The thickness of the surface protective layer can be arbitrarily selected, but is preferably 10 μm to 1 mm from the viewpoint of strength and transparency.

As this surface protective layer, a transparent substrate can be used by laminating it. At this time, a transparent substrate provided with an electrode layer can be used as the transparent substrate, and the number of steps of forming an electrode on the light control layer can be reduced by one. Naturally, the electrode on the transparent substrate is in contact with the light control layer.

The configuration of the liquid crystal optical element of the present invention described above will be further described with reference to the drawings. FIG. 1 is a schematic view of a liquid crystal optical element of the present invention in which a light control layer has a two-layer structure. The electrode layer 2, the light control layer 5, the interlayer electrode layer 3, the light control layer 5, and the outermost surface electrode layer 4 are sequentially laminated on the light absorbing substrate 1, and the extraction electrode 6 of each electrode layer is a side surface on which the extraction electrode is formed. 7 are collected on the surface of the light absorbing substrate 1.
As shown in FIG. 2, the side surface 7 on which the extraction electrode is formed is inclined at an angle 9 smaller than 90 ° with the plane 8 of the light absorbing substrate.

FIG. 3 shows that FIG. 1 has a two-layer structure,
The figure shows a three-layer structure, and each symbol is the same as in FIG. FIG. 4 is a schematic cross-sectional view of the liquid crystal optical element of the present invention in which two pixels are formed on a light absorbing substrate. The first light control layer is a green selective reflection layer 12, and the second layer is a light control layer. The light control layer is formed by laminating the red selective reflection layer 11 and the third light control layer by the blue selection reflection layer 13. The transparent element protection layer (surface protection layer) 22 is formed by the opening 10 (or the gap between pixels). 3) shows a state where it is filled. Here, as shown in FIG.
The thickness of 2 is preferably smaller than the thicknesses of the blue selective reflection layer 13 and the red selective reflection layer 11.

FIG. 5 shows a light control layer (1) in the configuration of FIG.
1, 12, 13) and the electrode layer (3, 4), a transparent protective film 14 thinner than the light control layer is provided. Further, FIG. 6 shows a configuration in which a transparent substrate 23 is provided on the outermost surface electrode layer in the configuration of FIG. 4, and this transparent substrate serves as a surface protection layer and has a transparent substrate provided with an electrode layer. As described above, it is possible to reduce one of the electrode forming steps on the dimming layer by using.

FIG. 7 shows the arrangement of the openings 10 when there are two pixels shown in FIG. FIG. 8 is a plan view showing a state in which four display pixels as shown in FIG. 7 are arranged on a substrate.

FIG. 9 shows a photochromic layer formed by applying a mixed solution 16 of a precursor of a polymer compound and a liquid crystal material to the surface of the electrode layer 2 formed on the light-absorbing substrate 1 and curing with a laser beam 15. FIG. 10 is a diagram showing a situation in which the liquid crystal optical element of the present invention in which an electrode layer (interlayer electrode layer) 3 is further laminated on the light control layer of FIG. 9 is taken out, and incident light during use is taken out. 19,
FIG. 3 is a diagram illustrating reflected light 20. In the figure, reference numeral 17 denotes a liquid crystal drop;
8 schematically shows a polymer compound.

The manufacturing method of the present invention comprises the steps of forming an electrode layer on a light-absorbing substrate, alternately laminating a dimming layer and an electrode layer on the light-absorbing substrate with the electrode layer, Forming an opening reaching the light-absorbing substrate from the outermost surface electrode layer, and forming an extraction electrode on the side surface of each display pixel. A step of laminating a protective film on the layer may be provided, or a step of forming a surface protective film for protecting the element on the outermost surface electrode may be provided. In the step of forming the electrode layer on the light absorbing substrate, ordinary sputtering, vapor deposition, and the like can be used. At this time, an active element such as a thin film transistor may be formed. As a step of forming a dimming layer on the light absorbing substrate with an electrode layer, at least a mixed solution of a liquid crystal material, a precursor compound of a polymer resin, and a photopolymerization initiator is coated on the light absorbing substrate using a spin coater or a bar coater. It is preferable to cast and cure by laser two-beam interference method. As a process of forming a protective film for protecting the light control layer, vapor deposition, spin coating, or the like can be used, but is not limited thereto. In forming the protective film, there may be a step of removing the liquid crystal material on the surface. As a process of forming an electrode layer on the light control layer having a protective film or the light control layer itself, deposition of a conductor,
There is a sputter or a coat of a solvent-soluble conductive polymer. As a process of forming the opening, a normal resist process can be used. As the step of forming the extraction electrode on the side surface, as in the step of forming the electrode layer of the light control layer, vapor deposition of a conductor, sputtering, or coating of a solvent-soluble conductive polymer can be used.

[0027]

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

Example 1 A solution containing a precursor compound of a polymer resin which is a mixture of ditrimethylol tricyclodecane diacrylate and a urethane acrylate oligomer, a nematic liquid crystal material TL215 (manufactured by Merck) and a polymerization initiator for curing visible light was prepared. Cast on a light absorbing substrate with electrode layer, wavelength 488nm
The first photochromic layer (blue selective reflection) having a thickness of 5 μm was prepared by using a two-beam interference method in a nitrogen atmosphere using an argon laser. ITO on this light control layer
After forming the electrode layer, a second light modulating layer (red selective reflection) having a thickness of 5 μm was formed using the same material and process as the first light modulating layer except that the angle of the laser was changed. further,
After forming the ITO electrode layer on the light control layer, the third light control layer having a thickness of 5 μm is made of the same material and process as the first light control layer and the second light control layer except that the laser angle is changed. An optical layer (green selective reflection) was prepared. Then, an ITO electrode layer was formed on the third light control layer. An opening was formed in each display pixel by using a resist process on the laminated light control layer. Then, an extraction electrode was formed on the side surface of each pixel using ITO, and further coated with an element protection layer. The obtained liquid crystal optical element displayed white when no voltage was applied. When an AC voltage was independently applied to each light control layer, a full-color display was obtained.

Example 2 A solution containing a precursor compound of a polymer resin, which is a mixture of 2-ethylhexyl acrylate and a urethane acrylate oligomer, a nematic liquid crystal material TL204 (manufactured by Merck), and a polymerization initiator for visible light curing was used as an electrode layer and Cast on a light-absorbing substrate with a thin-film transistor, photo-curing by a two-beam interference method in a nitrogen atmosphere using an argon laser with a wavelength of 488 nm, and perform a first light control layer with a thickness of 5 μm (blue selective reflection) Was prepared. After forming a protective film and an ITO electrode layer on this light control layer, the same light control layer as the first light control layer is used except that the laser angle is changed. A layer (green selective reflection) was made. Further, after forming the protective film and the ITO electrode layer on the light control layer, the same material and process as those of the first and second light control layers except that the angle of the laser is changed, and having a thickness of 5 μm. A third light control layer (red selective reflection) was produced. Then, a protective film and an I
A TO electrode layer was formed. An opening was formed in each display pixel by using a resist process on the laminated light control layer.
Then, an extraction electrode from each electrode layer was formed on the side surface of each display pixel using ITO. The outermost surface electrode layer (the electrode layer on the third light control layer) was connected to the counter electrode, and the other electrodes were connected to the source electrodes of each thin film transistor. Thereafter, an element protection layer was coated. The obtained liquid crystal optical element displayed white when no voltage was applied. When each dimming layer was independently driven in an active matrix by a thin film transistor, a full-color display was obtained.

Example 3 A precursor compound of a polymer resin which is a mixture of 2-ethylhexyl acrylate and ditrimethylol tricyclodecane diacrylate, a nematic liquid crystal material TL213 (manufactured by Merck), a photopolymerization initiator and a dye sensitizer were used. The solution was cast on a light-absorbing substrate with an electrode layer and a thin film transistor, and photocured by a two-beam interference method in a nitrogen atmosphere using an argon laser with a wavelength of 488 nm to control the first layer having a thickness of 7 μm. A layer (blue selective reflection) was produced. After forming an ITO electrode layer on this light control layer, a second light control layer (green) having a thickness of 5 μm is formed using the same material and process as the first light control layer except that the laser angle is changed. Selective reflection). Further, after forming the ITO electrode layer on the light control layer, except for changing the angle of the laser,
The same material and process as those of the first and second light control layers and a thickness of 7
A third light control layer (red selective reflection) of μm was prepared. Then, the laminated dimming layer was separated for each display pixel by using a resist process. Then, an extraction electrode from each electrode layer was formed on one side surface of each display pixel using ITO. Each lead electrode was connected to the source electrode of each thin film transistor. A transparent substrate on which a transparent electrode layer was attached was stuck so that the electrode layer was in close contact with the light control layer. The electrode layer attached to the transparent substrate was a counter electrode. The obtained liquid crystal optical element displayed white when no voltage was applied. When each dimming layer was independently driven in an active matrix by a thin film transistor, a full-color display was obtained.

Example 4 A liquid crystal optical element was manufactured under the same conditions as in Example 3 except that a conductive polymer (polyaniline) was used for the electrode layer between the light control layers. The obtained liquid crystal optical element displayed white when no voltage was applied. When each dimming layer was independently driven in an active matrix by a thin film transistor, a full-color display was obtained.

[0032]

As described above in detail, in the liquid crystal optical element of the present invention, the problem of parallax is solved because the holographic polymer-dispersed liquid crystal is laminated only through the electrode layer. Further, since multi-color and multi-color can be realized with one pixel, a holographic polymer-dispersed liquid crystal optical element with high resolution can be obtained. Furthermore, according to the manufacturing method of the present invention, the number of resist steps is small, the manufacturing of conductive columns is not required, and the laminated structure can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a two-layer structure of a liquid crystal optical element of the present invention.

FIG. 2 is a perspective view showing a side surface on which an extraction electrode of the liquid crystal optical element of the present invention is formed.

FIG. 3 is a perspective view schematically showing a three-layer structure of the liquid crystal optical element of the present invention.

FIG. 4 is a sectional view schematically showing a three-layer structure of the liquid crystal optical element of the present invention.

FIG. 5 is a sectional view schematically showing another example of the three-layer structure of the liquid crystal optical element of the present invention.

FIG. 6 is a sectional view schematically showing another example of the three-layer structure of the liquid crystal optical element of the present invention.

FIG. 7 is a schematic view showing an opening of the liquid crystal optical element of the present invention.

FIG. 8 is a plan view showing a display pixel of the liquid crystal optical element of the present invention.

FIG. 9 is a schematic view illustrating a photo-curing method for a liquid crystal optical element of the present invention.

FIG. 10 is a schematic cross-sectional view showing a state in which one light control layer of the liquid crystal optical element of the present invention is formed and further an electrode layer is formed.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 light absorbing substrate 2 electrode layer on light absorbing substrate 3 interlayer electrode layer 4 outermost surface electrode layer 5 light modulating layer 6 extraction electrode 7 side surface on which extraction electrode is formed 8 light absorption substrate plane 9 light absorption substrate plane and extraction electrode Angle formed by side surface to be formed 10 Opening 11 Red selective reflection layer 12 Green selective reflection layer 13 Blue selective reflection layer 14 Protective film 15 Laser light 16 Mixed solution of precursor of polymer compound and liquid crystal material 17 Liquid crystal droplet 18 Polymer compound 19 Incident light 20 Reflected light 21 Display pixel 22 Element protection layer 23 Transparent substrate

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masaharu Sato 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (56) References JP-A-4-178624 (JP, A) JP-A-3 -2825 (JP, A) JP-A-4-309922 (JP, A) JP-A-8-43848 (JP, A) JP-A-4-11224 (JP, A) JP-A-6-337643 (JP, A) JP-A-9-80401 (JP, A) JP-A-8-146456 (JP, A) JP-A-1-252936 (JP, A) JP-A-6-95133 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G02F 1/1333 G02F 1/1347 G02F 1/1368

Claims (13)

(57) [Claims] 1. A light modulating layer composed of a polymer resin and a liquid crystal material is alternately laminated with an electrode layer on one light absorbing substrate, and each light modulating layer is sandwiched between the electrode layers. In the liquid crystal optical element, wherein the liquid crystal material in the liquid crystal material is regularly arranged in the form of drops in the polymer resin, and selectively reflects light in the visible light region, at least for each display pixel A liquid crystal optical element having an opening. 2. The liquid crystal optical element according to claim 2, wherein the laminated light control layers are separated for each display pixel. 3. The liquid crystal optical element according to claim 2, wherein a side surface of each display pixel has an extraction electrode from each electrode layer. 4. The liquid crystal optical element according to claim 1, wherein an angle formed between a plane of the light absorbing substrate and a side surface of the opening forming the extraction electrode is less than 90 degrees. 5. The light control device according to claim 1, wherein three light control layers are laminated on the light absorbing substrate, and reflected light of each light control layer is red, green, and blue, respectively. The liquid crystal optical element according to the above. 6. The ordinary light refractive index of the liquid crystal material matches the refractive index of the polymer resin, the light control layer is in a light reflecting state when no voltage is applied, and the reflected light intensity decreases as the applied voltage increases. 6. The liquid crystal optical element according to claim 1, wherein: 7. The liquid crystal optical element according to claim 5, wherein the thickness of the light control layer that reflects green is smaller than the film thickness of the light control layer that reflects blue and red. 8. The liquid crystal optical element according to claim 1, wherein at least one electrode layer is made of a conductive polymer material. 9. The liquid crystal optical element according to claim 1, further comprising a protective film having a thickness less than the thickness of the light control layer between the light control layer and the electrode layer. 10. The liquid crystal optical element according to claim 1, wherein one electrode layer is electrically connected to the counter electrode, and the other electrode layer is electrically connected to the source electrode of the thin film transistor. 11. An electrode layer between the light absorbing substrate and the light control layer and an electrode layer between each light control layer are electrically connected to a source electrode of a thin film transistor provided on the light absorption substrate, respectively.
The liquid crystal optical element according to claim 10, wherein the electrode layer on the outermost surface is electrically connected to the counter electrode. 12. An electrode layer between the light absorbing substrate and the light modulating layer and an electrode layer between each light modulating layer are electrically connected to a source electrode of a thin film transistor provided on the light absorbing substrate, respectively.
The electrode layer on the outermost surface is electrically connected to a counter electrode formed on the light absorbing substrate.
2. The liquid crystal optical element according to 1. 13. A step of forming an electrode layer on a light-absorbing substrate, a step of alternately laminating a dimming layer and an electrode layer on the light-absorbing substrate with the electrode layer, and a step of forming a top electrode layer for each display pixel. A step of forming an opening reaching from the substrate to a light absorbing substrate, and a step of forming an extraction electrode on a side surface of each display pixel.