JPH0553098A - Production of liquid crystal device - Google Patents

Abstract

PURPOSE:To obtain the large-sized liquid crystal device having a light control layer which is not incorporated with bubbles without using a large-sized device by sticking substrates to each other while supplying a light control layer constituting material by a supplying nozzle. CONSTITUTION:Two sheets of the substrates 2 which have electrode layers and at least one of which are transparent are disposed in a wedge shape and while the light control layer constituting material 1 contg. a liquid crystal material, a photopolymerizable compsn. and a photopolymn. initiator is supplied by using the supply nozzle 3, this material is stuck to two sheets of the substrates 2 and is irradiated with UV rays. The polymerizable compsn. is then polymerized to form the light control layer constituted by forming a transparent high-polymer material having a three-dimensional network structure in the continuous layer of the liquid crystal material. The substrates 2 are such that two sheets thereof can face each other to have a proper spacing therebetween. At least one thereof are required to have transparency to allow the direct recognition of the light control layer of the liquid crystal layer crimped between two sheets of the substrates 2 and the layer having the transparent high-polymer material from the outside. The intrusion of the bubbles between the two substrates 2 is prevented at the time of injection in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of electrically controlling cut-off, opening, and transmission of light or illumination light, control of cut-off, and transmission of a field of view, displaying characters and figures, and high-speed response. The present invention relates to a method for manufacturing a liquid crystal device which is used for displaying various devices, a guide plate, a notice plate, a decorative display plate and the like by electrically switching the display.

[0002]

2. Description of the Related Art Two substrates, at least one of which has an electrode layer, are transparent, and a light control layer supported between the substrates,
A liquid crystal device in which the light control layer is a light control layer having a transparent polymer material formed by forming a three-dimensional network structure in a continuous layer of liquid crystal material is already known (Japanese Patent Laid-Open No. 1-19).
8725 publication).

This liquid crystal device has the advantages that it is possible to adjust lighting, adjust the field of view, and display characters and figures in a large size, and further, it is possible to perform time-division driving at a low voltage. In this liquid crystal device, a light control layer constituting material containing a liquid crystal material, a photopolymerizable composition and a photopolymerization initiator is interposed between at least one transparent substrate having an electrode layer, and the transparent substrate is passed through. It can be produced by polymerizing the polymerizable composition by irradiating with ultraviolet rays.

In this case, as a method of interposing a light control layer constituting material between two substrates, an injection hole portion of an empty cell having two transparent electrodes at least one side having an electrode layer is adjusted under vacuum. A vacuum injection method in which the dimming layer constituent material is immersed in the light layer constituent material, and the pressure is restored in this state to inject the dimming layer constituent material into the cell, or after applying the dimming layer constituent material on one substrate, the other A method of stacking substrates (hereinafter referred to as a bonding method) and the like are known.

[0005]

However, when the vacuum injection method is used, a large vacuum container is required to manufacture a large-sized liquid crystal device, resulting in a large-scale manufacturing apparatus. However, it has a drawback that the manufacturing cost is also high.

On the other hand, in the bonding method, a large-sized liquid crystal device can be manufactured without requiring a large-scale equipment such as a vacuum injection method, but on the other hand, it is possible to manufacture two large-scale liquid crystal devices via a light control layer constituent material. There is a drawback that air bubbles are easily mixed in when the substrates are bonded together, and as a result, the yield of liquid crystal devices is reduced.

The problem to be solved by the present invention is to provide a method of manufacturing a liquid crystal device capable of preventing air bubbles from being mixed in when two substrates are bonded together via a light control layer constituent material. .

[0008]

In order to solve the above-mentioned problems, the present invention provides (1) a liquid crystal material, a photopolymerizable composition and a photopolymerizable composition between two substrates having at least one transparent electrode layer. A first step of bonding two substrates by interposing a light control layer constituent material containing an initiator using a supply nozzle; and (2) irradiating the light control layer constituent material with ultraviolet rays, Provided is a method for producing a liquid crystal device, which comprises a second step of polymerizing a polymerizable composition to form a light control layer formed by forming a transparent polymer substance having a three-dimensional network structure in a continuous layer of a liquid crystal material. .

The substrate used in the present invention may be a rigid material such as glass or metal, or a flexible material such as a plastic film. The two substrates are opposed to each other and are separated by an appropriate distance. At least one of the substrates has transparency, and the liquid crystal layer and the transparent polymer substance sandwiched between the two substrates are provided. The light control layer, which is composed of the layers, 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 will be provided with appropriate transparency. Appropriate transparent or opaque electrodes may be disposed on the entire surface or a part of the substrate, depending on the purpose.

However, in the case of a flexible material such as a plastic film, it is preferable to use it after fixing it to a rigid material such as glass or metal. It should be noted that a spacer for holding a space can be usually interposed between the two substrates, as in a known liquid crystal device.

As the spacer, for example, Mylar,
Alumina, rod-type glass fiber, glass beads, polymer beads, and other various liquid crystal cells 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 kinds of liquid crystal compounds or substances other than the liquid crystal compounds. What is normally recognized as a liquid crystal material in this technical field may be used, and one having a positive dielectric anisotropy is preferable. The liquid crystal used is preferably a nematic liquid crystal, a smectic liquid crystal or a cholesteric liquid crystal, and a nematic liquid crystal is particularly preferable. To improve its performance, cholesteric liquid crystal, chiral nematic liquid crystal, chiral smectic liquid crystal, etc., chiral compound, dichroic dye, etc. 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 transition between the isotropic liquid and the liquid crystal. Temperature, melting point, viscosity, refractive index anisotropy (Δ
n), dielectric anisotropy (Δε), solubility with a polymerizable composition and the like 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)
A 5-substituted pyrimidine etc. can be mentioned.

Also, 3 formed in a continuous layer of liquid crystal material
As the transparent polymer substance having a dimensional network structure, a synthetic resin is preferable, and an ultraviolet curable resin obtained by polymerizing a polymer-forming monomer or oligomer is preferable.

Examples of the polymer-forming monomer that forms the transparent polymer substance include 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,
Acrylate, methacrylate or fumarate having a group such as allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxypropyl, dimethylaminoethyl, diethylaminoethyl; ethylene glycol, polyethylene glycol, propylene Mono (meth) acrylates or poly (meth) acrylates such as glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and pentaerythritol; vinyl acetate, butyric acid Vinyl or vinyl benzoate, acrylonitrile, cetyl vinyl ether, limonene, cyclohexene, diallyl phthalate, diallyl iso Tallates, 2-, 3- or 4-
Vinyl pyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethyl acrylamide or N-hydroxyethyl methacrylamide and their alkyl ether compounds; 2 mol or more of ethylene oxide or propylene oxide is added to 1 mol of neopentyl glycol. Di (meth) acrylate of diol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane; di or tri (meth) acrylate of triol; 2 mol or more per 1 mol of bisphenol A Di (meth) acrylate of diol obtained by adding ethylene oxide or propylene oxide of 2;
-A reaction product of 1 mol of hydroxyethyl (meth) acrylate and 1 mol of phenyl isocyanate or n-butyl isocyanate; poly (meth) acrylate of dipentaerythritol and the like can be mentioned, but trimethylolpropane triacrylate, tricyclo Decanedimethylol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, tris- (acryloxyethyl) isocyanurate and the like are particularly preferable.

Examples of the polymer-forming oligomer forming the transparent polymer substance include caprolactone-modified hydroxypivalic acid ester neopentyl glycol diacrylate.

As the polymerization initiator, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxycyclohexylphenylketone (manufactured by Ciba Geigy). Irgacure 184 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (Merck" Darocur 1116 "), benzyl dimethyl ketal (Ciba Geigy" Irgacure 65 "
1 "), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 (" Irgacure 907 "manufactured by Ciba Geigy), 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.) "Kayacure DETX") and ethyl p-dimethylaminobenzoate ("Kayacure-EPA" manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone ("Cantacure ITX" manufactured by Ward Prekinsop)
And a mixture of ethyl p-dimethylaminobenzoate and the like.

In order to control the thickness of the transparent polymer substance uniformly attached to the substrate, a spacer may be mixed with a solution of the liquid crystal material and the monomer or oligomer, or a solution of the organic solvent and the monomer or oligomer.
A spacer may be applied on one of the substrates.

As a method for forming a light control layer containing a transparent polymer substance having a uniform three-dimensional network structure on a substrate, for example, a liquid crystal material, a polymer-forming monomer or oligomer, and if necessary, Using a supply nozzle, the light control layer constituting material consisting of a uniform solution with a photopolymerization initiator is used.
After adhering the two substrates while injecting them between the two substrates, pressurizing them so that the thickness between the substrates becomes a predetermined thickness, and keeping the light control layer constituent material in an isotropic liquid state Is irradiated to form a light control layer having a transparent polymer substance having a three-dimensional network structure in the continuous layer of the liquid crystal material.

It is preferable that the constituent material of the light control layer is degassed in advance before being injected from the supply nozzle. The method of injecting the material for the light control layer, which is a feature of the method for manufacturing a liquid crystal device of the present invention, is briefly shown in FIG. In FIG. 1, 1 is a light control layer constituent material, 2 is a substrate, and 3 is a supply nozzle.

First, two substrates are installed in a wedge shape as shown by (1) in FIG. 1, and a supply nozzle is inserted into the narrowest portion between the wedge-installed substrates to adjust the light control layer. Inject constituent materials.

Subsequently, as in (2) and (3), while the light control layer constituent material is being injected, the supply nozzle is retracted and the angle between the two substrates is narrowed. At this time, it is preferable that the height of the narrowest portion between the substrates is lower than or the same as the position of the supply nozzle, and the substrate is adjusted so that the injected light control layer constituent material flows into the narrowest portion between the substrates. It is preferable to incline.

Finally, by injecting the material for forming the light control layer and then applying pressure, a cell having a constant thickness between the substrates as in (4) can be obtained. The shape of the supply nozzle may have a horizontally long injection port corresponding to the width of the substrate,
It may be any as long as it has a large number of small injection holes arranged in parallel and can uniformly inject a constant amount of the light control layer constituting material from each injection hole.

The moving speed of the supply nozzle and the diameter of the nozzle may be appropriately adjusted according to the injection amount of the material for the light control layer and the physical properties such as the viscosity of the material for the light control layer to be used. If the average diameter of the shape of the three-dimensional network structure formed by the transparent polymer material by such a manufacturing method is too large or too small as compared with the wavelength of light, the light scattering property tends to deteriorate. , 0.2-2 μm is preferable.
In addition, the layer thickness of the layer having the transparent polymer substance is 2 to 20 depending on the purpose of use in order to obtain a sufficient contrast between the opacity due to light scattering and the transparency achieved electrically.
The range of μm is preferred.

[0026]

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.

Hereinafter, in the Examples, "%" means "% by weight".
And each of the evaluation characteristics means the following symbols and contents. T ₀ : White turbidity; Light transmittance (%) when applied voltage is 0 T ₁₀₀ : Transparency; Light transmittance (%) when the applied voltage hardly increases with increasing applied voltage V ₁₀ : Threshold: _Applied voltage (V _rms ) V ₉₀ at which light transmittance is 10% when T ₀ is 0% and T ₁₀₀ is 100%: Saturation voltage; Same as above, applied voltage at which light transmittance is 90% ( V _rms ) CR: contrast = T ₁₀₀ / T ₀ (Example 1)

[0028]

[Chemical 1]

A liquid crystal composition (A) consisting of was prepared. The properties of this liquid crystal composition (A) were as follows. Two ITO electrode glass substrates (30 cm) coated with 11.0 micron glass fiber spacers on one substrate
X 30 cm) was assembled into a wedge shape with an angle of 45 degrees. Next, 80.0% of the above liquid crystal composition (A), 19.6% of "KAYARAD-HX-620" (caprolactone-modified hydroxypivalate neopentylglycol diacrylate manufactured by Nippon Kayaku Co., Ltd.) as a photopolymerizable composition, and initiation of photopolymerization "Darocur 1173" (2-hydroxy-2-methyl-1-phenylpropan-1-one manufactured by Merck & Co., Inc.) as an agent was evacuated from the light control layer constituting material, and an injection port having a diameter of 0.5 mm was formed into 6 Using a supply nozzle having a width of 30 cm and a height of 1 mm, while injecting between the two substrates assembled in the wedge shape,
While retreating at a speed of 60 mm per minute, the wedge-shaped angle of the two substrates was narrowed, and the two substrates were bonded via the light control layer constituting material for 5 minutes.

Next, while maintaining the whole substrate at 38 ° C.,
Irradiate with W / cm ² of UV light for 60 seconds to adjust the thickness of the light control layer to 11.5.
A micron liquid crystal device was obtained. When the light control layer of the obtained liquid crystal device was observed with an electron microscope, a transparent polymer substance having a three-dimensional network structure was confirmed.

As a result of measuring various characteristics relating to the applied voltage and the light transmittance of this liquid crystal device, T ₀ = 3.2%, T ₁₀₀ = 89
_{%, CR = 27.8, V 10} = 7.1V rms, V 90 = 16.1V rms,
ΔV = 0.44 V _rms .

No bubbles were observed in the obtained liquid crystal device. (Comparative Example) In Example 1, except that the light control layer constituting material was applied onto one substrate using a bar coater, and then the other substrate was superposed and two substrates were bonded together.
A liquid crystal device was obtained in the same manner as in Example 1.

When the light control layer of the obtained liquid crystal device was observed with an electron microscope, a transparent polymer substance having a three-dimensional network structure was confirmed. However, it was a device that could not be put to practical use because many bubbles were observed.

[0034]

According to the method of manufacturing a liquid crystal device of the present invention, it is possible to obtain a large-sized liquid crystal device having a light control layer in which bubbles are not mixed, without using a large device.

[Brief description of drawings]

FIG. 1 is a process diagram showing a part of a method for manufacturing a liquid crystal device of the present invention in a simplified manner.

[Explanation of symbols]

 1 Light control layer constituent material 2 Substrate 3 Supply nozzle

Claims (1)

[Claims] 1. A supply nozzle is provided with a dimming layer constituent material containing a liquid crystal material, a photopolymerizable composition and a photopolymerization initiator, between two substrates having at least one transparent electrode layer. The first step of adhering the two substrates while injecting and (2) irradiating the dimming layer-constituting material with ultraviolet rays to polymerize the polymerizable composition so that 3 in a continuous layer of the liquid crystal material. A method for producing a liquid crystal device, comprising a second step of forming a light control layer formed by forming a transparent polymer material having a dimensional network structure.