JPH1090654A - Production of liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a light scattering type liquid crystal device having a light-controlling layer of a liquid crystal and a transparent solid material, by which reflection of active rays on the interface between a substrate or a scattering layer and a light-shielding material such as a black matrix which partly cuts the active rays is prevented, and by which a process to wipe a liquid on the substrate can be omitted. SOLUTION: A liquid crystal device having a light-controlling layer comprising a liquid crystal material and a transparent solid material between the two substrates is produced by interposing a light-controlling layer material containing a liquid crystal material, polymerizable compsn. and polymn. initiator between two substrates at least one of which is transparent, and then irradiating the material through a scattering layer with active rays to polymerize the photopolymerizable compsn. In this method, active rays are made to irradiate while an elastic material which transmits active rays is held between the scattering layer and the substrate in such a manner that the elastic material is tightly adhered to the whole surfaces of the scattering layer and the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal device capable of forming a large area, and more specifically, to electrically control the blocking, opening, and limiting, blocking, and transmitting of light or illumination light. It is used as a screen for blocking the view of a building window or a show window, or as a curtain for lighting control, and displays characters and figures, and switches the display electrically with high-speed response. Accordingly, the present invention relates to a method for manufacturing a liquid crystal device used as a high information display such as a display or a projection device of an OA apparatus, an advertisement board, a guide board, a decorative display board, or the like.

[0002]

2. Description of the Related Art Bright and bright without the need for a polarizing plate and alignment treatment.
JP-A-58-501631, US Pat. No. 4,43,43 discloses a large and inexpensive liquid crystal device with good contrast.
JP-A-5,047, JP-T-61-501345 and JP-A-62-48789 disclose liquid crystal encapsulation in which liquid crystal droplets are dispersed in a polymer to form a film of the polymer. A light-modulating layer has been proposed.

[0003] In the technique disclosed in the above specification, liquid crystal molecules encapsulated by polyvinyl alcohol are exposed to an electric field if they have a positive dielectric anisotropy in a thin layer. as the liquid crystal molecules under is arranged in the direction of the electric field, the refractive index n _p of the liquid crystal of the ordinary refractive index n _o and the polymer
When are equal, transparency is exhibited. When an electric field is removed, the liquid crystal molecules are returned to the random sequence, the refractive index of the liquid crystal droplets is deviated from the n _o, the liquid crystal droplets scatter light at the boundary surface, since blocking the transmission of light, Ususotai is It becomes cloudy.

[0004] In addition to the above-mentioned techniques, some techniques for forming a thin film of a polymer in which encapsulated liquid crystals are dispersed and encapsulated are known.
No. 1208 discloses a liquid crystal dispersed in an epoxy resin,
Japanese Patent Application No. 61-305528 and Japanese Patent Application Laid-Open No. 62-2231 disclose that a liquid crystal and a photocurable resin are phase-separated by irradiating a liquid mixture of the photocurable resin and the liquid crystal with ultraviolet rays. A method of forming a light control layer dispersed therein has been reported.

In order to drive a liquid crystal device having such a dimming layer, a voltage of about 20 V or more is required.
In many cases, a high voltage of 40 V or more was required.

Further, light scattering performance required for a liquid crystal device,
In order to obtain light transmission performance, it is necessary to optimize the matching and mismatch between the refractive indices of the liquid crystal material and the resin component, and there is a limit in selecting a combination of the liquid crystal material and the resin material.

[0007] From these problems, in order to enable low-voltage driving characteristics, high-contrast, and time-division driving, which are important characteristics required for practical use of the liquid crystal device as described above, Japanese Patent Application Laid-Open No. 1-187725. And JP-A-2-85
No. 822 discloses a liquid crystal device having a liquid crystal material forming a continuous layer, and a light modulating layer formed by forming a three-dimensional network polymer material in the continuous layer.

In such a liquid crystal device, a light modulating layer forming material containing a liquid crystal material, a photopolymerizable composition and a photopolymerization initiator is interposed between two transparent substrates having an electrode layer.
By irradiating light in the isotropic liquid state of the light modulating layer forming material to polymerize the photopolymerizable composition, a high performance having a light modulating layer composed of a liquid crystal material and a transparent polymer material as described above. A liquid crystal device can be manufactured.

In this method of manufacturing a liquid crystal device, in the case of a liquid crystal device comprising an active element, a black matrix or a substrate with a color filter, it is necessary to irradiate active light from the black matrix or the active element side. As a result of being blocked or dimmed, it has been difficult to form a light modulating layer having a uniform three-dimensional network structure over the entire surface of the pixel. In order to solve this problem, Japanese Patent Application Laid-Open No. 6-294953 proposes a method of irradiating the substrate with actinic rays through a scattering layer such as ground glass.

[0010]

In this method, when air or the like is present between the scattering layer and the substrate, the amount of active light is reduced due to reflection at the interface, and the polymerizable composition is cured. In order to secure a sufficient amount of light, the irradiation time of active light must be lengthened, which is not preferable. Therefore, in this method, a method of interposing a liquid such as silicone oil between the scattering layer and the substrate has been used in order to prevent generated light from being reflected at the interface.

However, in this method, after irradiating with the actinic ray, it is troublesome to take a removing means such as wiping the liquid.

An object of the present invention is to provide a method for manufacturing a light-scattering type liquid crystal device having a light control layer made of a liquid crystal and a transparent solid substance, wherein an active light such as a black matrix is partially shielded. For the substrate, it is possible to prevent the reflection of the actinic ray at the interface between the substrate or the scattering layer and the space created between them, and to omit the steps such as wiping off the liquid as in the above-described conventional technique. It is an object of the present invention to provide a method for manufacturing a liquid crystal device.

[0013]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have reached the present invention. That is, in order to solve the above-mentioned problems, the present invention provides (1) a liquid crystal material, (2) a polymerizable composition, and (3) a polymerization initiator between at least one transparent substrate having an electrode layer. After interposing a dimming layer-forming material containing, by irradiating actinic rays through a scattering layer to polymerize the photopolymerizable assembly, a liquid crystal material and a transparent solid are interposed between two substrates. In a method of manufacturing a liquid crystal device having a light modulating layer made of a substance, an active material having a property of transmitting an active light between the scattering layer and the substrate is tightly interposed between the scattering layer and the substrate. And a method for manufacturing a liquid crystal device characterized by irradiating the liquid crystal device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate used in the present invention may be a rigid material, for example, glass, metal, or the like, or a flexible material, for example, a plastic film. The two substrates are opposed to each other and are obtained at an appropriate distance. At least one of the substrates has transparency, and a liquid crystal layer and a layer having a transparent solid substance sandwiched between the two substrates. The dimming layer must be visible from the outside world. However, complete transparency is not essential. If the liquid crystal device is used to act on light passing from one side of the device to the other, both substrates are provided with the appropriate transparency. Appropriate transparent and opaque electrodes may be disposed on the entire or partial surface of the substrate depending on the purpose.

The thickness of the light control layer of the liquid crystal device obtained by the manufacturing method of the present invention is preferably in the range of 5 to 100 μm.
The range of 8 to 50 μm is particularly preferred.

A light control layer composed of a liquid crystal material and a transparent solid substance is interposed between the two substrates, and between the two substrates, a distance maintaining layer is usually provided as in a well-known liquid crystal device. Can be interposed.

As the spacer, for example, Mylar,
Various types of liquid crystal cells such as alumina and polymer beads can 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 liquid crystal compounds or a substance other than the liquid crystal compound. Any material which is generally recognized as a liquid crystal material in this technical field may be used, and a material having a positive dielectric anisotropy is preferable. As a liquid crystal to be used, a nematic liquid crystal, a smectic liquid crystal, and a cholesteric liquid crystal are preferable, and a nematic liquid crystal is particularly preferable. In order to improve the performance, a cholesteric liquid crystal, a chiral nematic liquid crystal, a chiral smectic liquid crystal, a chiral compound, a dichroic dye, or the like may be appropriately contained.

The liquid crystal material used in the present invention is preferably a compounded composition comprising at least one compound selected from the group of compounds shown below. The properties of the liquid crystal material, that is, the phase transition between isotropic liquid and liquid crystal Temperature, melting point, viscosity, refractive index anisotropy (Δ
n), the dielectric constant anisotropy (Δε), the solubility with the polymerizable composition, and the like can be appropriately selected, blended, and used.

As the liquid crystal material, benzoic acid ester type,
Cyclohexylcarboxylic acid ester type, biphenyl type,
Terphenyl, phenylcyclohexane, biphenylcyclohexane, pyrimidine, pyridine, dioxane, cyclohexanecyclohexane ester,
Various liquid crystal compounds such as cyclohexylethane, tolan and alkenyl are used.

For example, 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 and the like can be mentioned.

The transparent solid substance formed in the light modulating layer may be a substance in which a liquid crystal material is dispersed in a polymer in the form of droplets, but more preferably has a three-dimensional network structure.

The transparent solid substance is preferably formed in a three-dimensional network in a continuous layer of the liquid crystal material. By forming the disordered alignment state of the liquid crystal material, an optical interface is formed, Strong scattering can be expressed.

As the transparent solid substance of the present invention, a synthetic resin is preferable. As a material giving a three-dimensional network structure, a photocurable resin obtained by polymerizing a polymer-forming monomer or oligomer or a composition thereof is suitable.

As a method of forming a three-dimensional network structure by a transparent solid substance formed between substrates, an active light beam is applied while a light modulating layer forming material encapsulated in a panel is kept in an isotropic liquid state. Irradiation may be used to polymerize a polymerizable composition containing a polymer-forming monomer or oligomer.

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,
Having a group such as cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxypropyl, dimethylaminoethyl, diethylaminoethyl, etc. Acrylates, methacrylates or fumarates; mono- (meth) acrylates such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and pentaerythritol A) acrylate or poly (meth) acrylate; vinyl acetate, vinyl butyrate or vinyl benzoate, acrylonitrile , Cetyl vinyl ether, limonene, cyclohexene, diallyl phthalate, diallyl isophthalate, 2-, 3- or 4-vinylpyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethylacrylamide or N-
Hydroxyethyl methacrylamide and their alkyl ether compounds, trimethylolpropane, di or tri (meth) acrylate of triol obtained by adding at least 3 mol of ethylene oxide or propylene oxide to 1 mol, 2 mol / mol of neopentyl glycol
Reaction product of 1 mol of di (meth) acrylate, 2-hydroxyethyl (meth) acrylate of diol obtained by adding at least ethylene oxide or propylene oxide with 1 mol of phenyl isocyanate or n-butyl isocyanate, Erythritol poly (meth) acrylate, tris- (hydroxyethyl) -isocyanuric acid poly (meth) acrylate,
Poly (meth) tris- (hydroxyethyl) -phosphate
Acrylate, mono (meth) acrylate or di (meth) acrylate of di- (hydroxyethyl) -dicyclopentadiene
Acrylate, neopentyl glycol pivalate di (meth) acrylate, caprolactone-modified neopentyl glycol di (meth) acrylate hydroxypivalate, linear aliphatic di (meth) acrylate, polyolefin-modified neopentyl glycol di (meth) acrylate, and the like. be able to.

As the polymer-forming oligomer, for example, epoxy (meth) acrylate, polyester (meth) acrylate, polyurethane (meth) acrylate, polyether (meth) acrylate and the like can be used.

The content of the liquid crystal material and the polymerizable composition in the light control layer forming material is preferably in the range of 60:40 to 95: 5 by weight, and particularly preferably in the range of 75:25 to 85:15. If the amount of the liquid crystal material is too large or too small, the dispersion state of the liquid crystal material and the transparent solid substance will not be uniform.
Not preferred.

Examples of the polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one ("Darocur 1173" manufactured by Merck) and 1-hydroxycyclohexylphenyl ketone ("Ciba Geigy"). Irgacure 184 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
-One (“Darocur 1116” manufactured by Merck), benzyldimethyl ketal (“Irgacure 651” manufactured by Ciba-Geigy), 2-methyl-1- [4- (methylthio)
Phenyl] -2-morpholinopropanone-1 ("Irgacure 907" manufactured by Ciba-Geigy), 2,4-diethylthioxanthone ("Kayacure DET" manufactured by Nippon Kayaku Co., Ltd.)
X ") and ethyl p-dimethylaminobenzoate (" Kayacure-EPA "manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone (" Kantacure ITX "manufactured by Ward Prekinsopp) and ethyl p-dimethylaminobenzoate And the like.

In order to interpose the dimming layer forming material between the two substrates, the dimming layer forming material is placed in an empty cell composed of two substrates whose peripheral parts except for the injection holes are solidified with a sealing material. Although a method of injecting may be used, a method of uniformly applying the solution to one of the substrates using a suitable solution coater or a spin coater, and then overlapping and pressing the other substrate may be used.

The actinic rays include, for example, ultraviolet rays, EB
(Electron beam), visible light and the like. In particular, it is preferable to use an ultraviolet irradiation device having an emission wavelength in a wavelength region of 365 nm, and examples of such an ultraviolet light source include a metal halide lamp, an ultra-high pressure mercury lamp, and a high pressure mercury lamp.

Because of the heating caused by the irradiation of the ultraviolet rays, the temperature of the substrate rises so much that it may be difficult to obtain predetermined characteristics. Therefore, it is necessary to control the temperature rise as much as possible. For that purpose, it is effective to cut off an infrared portion generated from the ultraviolet irradiation light source, and it is effective to interpose such an infrared cut filter between the light source and the substrate.

The scattering layer that scatters the actinic ray irradiation light can be used without particular limitation as long as it is a scattering plate that scatters the actinic ray. The space between the substrate and the intervening substrate is preferable. In particular, it is effective to arrange the substrate in close contact with the surface of the substrate so as to reduce the loss of scattered light. As the scattering layer, for example, ultraviolet light, opal glass for scattering active light such as visible light or the surface of an active light transmitting substrate is uneven, and a scattering plate for scattering active light, for example, ground glass that can be used at very low cost Is mentioned.

The elastic body provided between the scattering layer and the substrate is
Preferably, it has a property of transmitting sufficient actinic rays so that polymerization phase separation proceeds properly, has strength as an elastic body, easily adheres to the substrate and the scattering layer, and is easily peelable. Further, those having a refractive index equivalent to that of the substrate and the diffusion layer are preferable. Among such materials, a silicone resin is particularly effective because it has excellent transmittance in the ultraviolet region and thus has a small loss of actinic rays. As such an elastic body, various silicone rubbers or polymers of silicone gel can be used. Examples of commercially available elastic bodies include silicone rubber manufactured by Shin-Etsu Chemical Co., Ltd .; "KE103", "KE106", and "K".
E109 ", a silicon gel made by the company;" KE105 ",
“KE1051”, “KE104Gel”, “KE11
0 Gel "and the like.

[0035]

The present invention will be described below in more detail with reference to Examples of the present invention. However, the invention is not limited to these examples.

In the following examples, "parts" and "%" represent "parts by weight" and "% by weight", respectively. In addition, each of the evaluation characteristics means the following symbols and contents. (1) T ₀ : white turbidity; light transmittance (%) when applied voltage is 0 (2) T ₁₀₀ : transparency; light transmittance when light transmittance hardly increases as applied voltage is increased ( %) (3) V ₉₀ : Saturation voltage; same as above. _Applied voltage (V _rms ) at which the light transmittance becomes 90%.
It measured using the Unimeter with -365PD (UIT-101). (4) CR: contrast = T ₁₀₀ / T ₀

Example 1 10 μm “Micropearl SP210” (polymer beads manufactured by Sekisui Fine Chemical Co., Ltd.) was sprayed on the common electrode side of a transparent substrate having an ITO electrode as a common electrode. Next, an ITO pixel electrode connected to an active element of a thin film transistor (TFT) made of a Cd-Se semiconductor and a peripheral portion excluding a portion serving as an injection hole of a substrate of a substrate with a black matrix (aperture ratio: 60%), After applying DSA-001 (Rodick's sealant), the two substrates were bonded together such that the electrodes were on the inside, and were baked and cured to obtain 10 cm × 1
An empty cell having a 0 cm square and a cell thickness of 10.2 μm was prepared.

Next, a light control layer forming material (“PNM-20” manufactured by Roddick Co., Ltd.) was injected into the empty cell by vacuum injection.
1)) was injected while maintaining the temperature at 30 ° C.

A transparent elastic body having a thickness of 2 mm formed by curing silicone rubber KE106 (manufactured by Shin-Etsu Chemical Co., Ltd.) is overlaid on the entire surface of one substrate of the cell into which the light modulating layer forming material has been injected. After laminating frosted glass as a diffusion layer on the body, the illuminance on the substrate surface was 40 mW / cm ^2.
A liquid crystal having a light control layer composed of a liquid crystal material and a transparent solid substance is cured by irradiating ultraviolet light (light source: metal halide lamp) for 30 seconds to cure the polymerizable composition in the light control layer forming material. Got the device. After irradiation with ultraviolet rays, the transparent elastic body made of silicone rubber could be easily peeled off from the substrate.

When the dimming layer of the obtained liquid crystal device was observed with a scanning electron microscope, a uniform three-dimensional network polymer material was confirmed.

As a result of measuring the relationship between the applied voltage and the light transmittance of the obtained liquid crystal device, T ₀ = 1.2%, T ₁₀₀ = 53.9%, CR = 44.1,
V ₉₀ = 3.7 V _rms .

Comparative Example 1 The procedure of Example 1 was repeated, except that a transparent silicone oil was interposed between the ground glass and the substrate in place of the transparent elastic body made of silicone rubber.
In the same manner as in Example 1, a liquid crystal device having the same characteristics as in Example 1 and having a uniform three-dimensional network polymer material in the light control layer was obtained. In addition, after irradiating with ultraviolet rays, wiping and solvent washing were required to remove the silicone oil from the substrate, which was troublesome and expensive.

[0043]

According to the manufacturing method of the present invention, it is possible to efficiently irradiate the substrate with the black matrix with the diffused light of the active light, and it is easy to perform post-processing after the irradiation. Makes the manufacturing process more efficient, and productivity is greatly improved. Therefore, the present invention is useful as a method for manufacturing a liquid crystal device.

Claims (2)

[Claims] 1. A light modulating layer forming material containing (1) a liquid crystal material, (2) a polymerizable composition, and (3) a polymerization initiator, between two substrates having at least one transparent electrode layer. A liquid crystal having a light modulating layer composed of a liquid crystal material and a transparent solid substance between two substrates by polymerizing the photopolymerizable assembly by irradiating active light through a scattering layer after intervening. In a method for manufacturing a device, a liquid crystal is irradiated with active light while an elastic body having a property of transmitting active light between the scattering layer and the substrate is closely interposed between the scattering layer and the substrate. Device manufacturing method. 2. The method for manufacturing a liquid crystal device according to claim 1, wherein the elastic body having a property of transmitting actinic rays is a silicone resin.