JPH05173151A - Manufacture of liquid crystal device - Google Patents

Abstract

PURPOSE:To shorten the time of a vacuum state required for liquid crystal material or dimming layer forming material injection by forming a cell where no impurity sticks without using a press-contacting jig by sticking two substrates on each other under a vacuum while one of the substrate which has the electrode layer is transparent. CONSTITUTION:The peripheral part of one of the two substrates which has the electrode layer and is transparent is coated with a seal agent except at the injection hole of one substrate and suck on the other substrate under a vacuum, and the hole is sealed by using a 1st peelable sealing agent, which is heated and cured to form a cell. Then the sealing agent is peeled under a vacuum and after a liquid crystal material or dimming layer forming material is injected into the cell, the hole is sealed at atmospheric pressure by using a 2nd sealing agent and irradiated with an active light beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal device capable of forming a large area, and more particularly, to blocking or opening a field of view and limiting or blocking transmission of light or illumination light.
The transmission can be electrically operated, and it is used as a screen for blocking the field of view in building windows and show windows, and as a curtain for daylighting control. The present invention relates to a method for manufacturing a liquid crystal device which is used as a high information display body such as a display of an OA equipment or a projection device, an advertising board, a guide board, a decorative display board, etc. by electrically switching the display.

[0002]

2. Description of the Related Art Conventionally, liquid crystal devices are of TN (twisted nematic) type using nematic liquid crystal,
The STN (Super Twisted Nematic) type has been put into practical use.

Further, in order to enable low-voltage driving characteristics, high contrast, and time-division driving, which are important characteristics required for practical use of liquid crystal devices, JP-A-1-198725.
The liquid crystal material forms a continuous layer, and in this continuous layer,
A liquid crystal device having a light control layer formed by forming a three-dimensional network-like solid substance is disclosed.

In such a liquid crystal device, one of two transparent substrates having an electrode layer is coated with a sealant, the other substrate is superposed on the other, and a sealant is used to apply the sealant. The cells were created by bonding by heating and curing.

In order to inject the liquid crystal material or the light control layer forming material into this cell, it was necessary to leave the cell in a vacuum for a long time to sufficiently reduce the pressure in the cell.

[0006]

However, in such a bonding method, it is indispensable to use a heavy crimping jig and a large heating furnace for heating it.
Further, since it is carried out under normal pressure, there is a limit in maintaining cleanliness.

Further, when the liquid crystal material or the light control layer forming material is injected, the inside of the cell must be in a vacuum state, but due to the small cell thickness and the presence of volatile substances such as water on the surface of the substrate. In order to bring the cell into a sufficient vacuum state, it was necessary to keep the cell under vacuum in the injection tank for a long time. This was necessary for a longer time, especially for larger cells.

[0008] The problem to be solved by the present invention is to provide a method for manufacturing a liquid crystal device using a cell produced in a cleaner atmosphere without the need for a crimping jig, and further to bring the inside of the cell into a vacuum state. A method of manufacturing a liquid crystal device, which shortens the time of a vacuum state in an injection tank for the purpose.

[0009]

The present inventor has accomplished the present invention as a result of extensive studies to solve the above problems. That is, the present invention provides a method for manufacturing a first liquid crystal device,
(1) A sealant is applied to the peripheral portion of one of the two substrates having at least one transparent electrode substrate, excluding the injection hole, and the sealant is defoamed and the substrate surface is dried under vacuum. The second step of (2) bonding the substrate and the other substrate to each other under vacuum to form a cell, and sealing the injection hole with a first sealing agent capable of peeling. 3) Third step of re-pressurizing and main curing the sealing agent under normal pressure, (4)
A fourth step of removing the first sealing agent under vacuum, injecting a liquid crystal material into the cell, and applying the second sealing agent to the injection hole portion,
(5) There is provided a method for producing a liquid crystal device including a fifth step of curing the second pore-sealing agent by irradiating the cell obtained in the fourth step with an actinic ray.

Furthermore, the present invention provides, as a second method for manufacturing a liquid crystal device, (1) a sealant is applied to a peripheral portion of one of two substrates having at least one having an electrode layer, which is transparent, except an injection hole. Then, the first step of defoaming the sealant of the substrate and drying the substrate surface under vacuum, (2) bonding this substrate and the other substrate under vacuum to create a cell, and the injection hole can be peeled off Second step of sealing using the first sealing agent, (3) Third step of re-pressurizing and main curing of the sealing agent under normal pressure, (4) Peeling off the first sealing agent under vacuum Then, the fourth step of injecting the liquid crystal material, the polymerizable composition and the light control layer constituting material containing the polymerization initiator into the cell, and applying the second sealing agent to the injection hole portion, (5) the fourth step The second pore-sealing agent and the polymerizable composition are polymerized and cured by irradiating the cell obtained in the step with an actinic ray. , To provide a method of manufacturing a liquid crystal device having a fifth step of forming a liquid crystal material and the light control layer formed of a transparent solid material.

Since the method for manufacturing a liquid crystal device of the present invention does not use a crimping jig, it does not handle heavy objects and does not require equipment for heavy objects as compared with the conventional manufacturing method. In addition, there is no unevenness in the cell thickness due to a defective crimping jig.

Furthermore, since the substrates are bonded under reduced pressure, a higher degree of cleanliness than in clean air can be obtained.

When the liquid crystal material or the light control layer forming material is vacuum-injected, the inside of the cell is already in a vacuum state to some extent. It is possible to reduce the time in a vacuum state to less than half by the present invention.

The substrate used in the present invention may be a rigid material such as glass or metal. And the substrate is 2
A plurality of sheets are opposed to each other with an appropriate distance, at least one of which is transparent, and a dimming layer composed of a layer having a liquid crystal layer and a transparent solid substance sandwiched between the two sheets. It must be visible from the outside world. However,
It does not require complete transparency.

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 appropriate transparency. .

On this substrate, an appropriate transparent or opaque electrode may be arranged on the whole surface or a part thereof depending on the purpose.

A dimming layer made of a liquid crystal material and a transparent solid substance is interposed between the two substrates, and the two substrates are usually spaced apart from each other as in a known liquid crystal device. It is also possible to interpose a holding spacer.

As the spacer, for example, Mylar,
A variety 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 kinds of liquid crystal compounds or substances other than liquid crystal compounds. Any material generally 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. In order to improve the performance, cholesteric liquid crystals, chiral nematic liquid crystals, chiral smectic liquid crystals, chiral compounds, dichroic dyes and 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 transition between the isotropic liquid and the liquid crystal. Temperature, melting point, viscosity, refractive index anisotropy (Δ
n), the dielectric anisotropy (Δε), the solubility with the polymerizable composition, and the like can be taken into consideration and appropriately selected and blended.

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 content of the liquid crystal material and the polymerizable composition in the light control layer forming material used in the second method for producing a liquid crystal device of the present invention is preferably in the range of 60:40 to 95: 5 by weight ratio. , 7
The range of 5:25 to 85:15 is particularly preferable. This is not preferable when the liquid crystal material is too much or too little because the liquid crystal material and the transparent solid substance are not dispersed in a uniform state, and the dimming function due to light scattering tends to deteriorate.

The transparent solid substance formed in the light control layer may be one in which a liquid crystal material is spherically dispersed in a polymer, but one having a three-dimensional network structure is more preferable.

The three-dimensional network portion of the transparent solid substance is preferably filled with a liquid crystal material, and the liquid crystal material preferably forms a continuous layer. It is essential for forming the boundary surface and expressing light scattering.

A synthetic resin is suitable as the transparent solid substance of the present invention. A photo-curable resin obtained by polymerizing a polymer-forming monomer or oligomer is preferable as a material that gives a three-dimensional network structure.

As a method for forming a three-dimensional network structure by the transparent solid substance formed between the substrates, active light is irradiated while the light control layer forming material enclosed in the cell is kept in an isotropic liquid state. Then, a method of polymerizing the photopolymerizable composition may be mentioned.

Examples of the polymer-forming monomer forming the transparent solid 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, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxypropyl, Acrylate, methacrylate or fumarate having a group such as dimethylaminoethyl, diethylaminoethyl, etc .; ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, triglyceride Mono (meth) acrylates such as methylolpropane, glycerin and pentaerythritol, or poly (meth) actuates Lilate; vinyl acetate, vinyl butyrate or vinyl benzoate, acrylonitrile, cetyl vinyl ether, limonene, cyclohexene, diallyl phthalate, diallyl isophthalate, 2-, 3- or 4-
Vinyl pyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethyl acrylamide or N-hydroxyethyl methacrylamide and their alkyl ether compounds, trimethylolpropane, 1 mol of ethylene oxide or propylene oxide of 3 mol or more Di- or tri (meth) acrylate of triol obtained by addition, di (meth) acrylate of diol obtained by addition of 2 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol, 2-hydroxyethyl (meth) )
Reaction product of 1 mol of acrylate and 1 mol of phenyl isocyanate or n-butyl isocyanate, poly (meth) acrylate of dipentaerythritol, poly (meth) acrylate of tris- (hydroxyethyl) -isocyanuric acid, tris- (hydroxyethyl) ) -Phosphoric acid poly (meth) acrylate, di- (hydroxyethyl) -dicyclopentadiene mono (meth) acrylate or di (meth) acrylate, pivalic acid neopentyl glycol di (meth) acrylate, caprolactone modified hydroxypivalic acid Examples include neopentyl glycol di (meth) acrylate, linear aliphatic di (meth) acrylate, polyolefin-modified neopentyl glycol di (meth) acrylate, and the like.

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.

Examples of the polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one ("Darocur 1173" manufactured by Merck), 1-hydroxycyclohexyl phenyl ketone ("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.

The peelable first pore-sealing agent used in the present invention may be one having an adhesive property, or one capable of sealing a hole by vacuum adsorption, and its material is not particularly limited, but is flexible. It is more desirable to have one.

Examples of the adhesive material include vinyl tape and cellophane tape.

Examples of materials that can be sealed by vacuum adsorption include rubber, metal, and plastic pieces and films.

The second sealing agent used in the present invention is as follows:
Although those used for ordinary liquid crystal devices can be used without particular limitation, in the second method for manufacturing a liquid crystal device of the present invention, a seal capable of sealing simultaneously with the formation of the dimming layer by irradiation with actinic rays. It is desirable to use pores.

As the actinic ray source for polymerizing the second sealing agent or the photopolymerizable composition, for example, a mercury lamp, a metal halide lamp or the like can be used.

The thickness of the light control layer of the liquid crystal device obtained by the present invention is preferably in the range of 5 to 50 μm, particularly preferably in the range of 8 to 25 μm.

[0036]

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.

(Example 1) Two sheets of ITO having an alignment film
As a sealant on the periphery of one glass substrate with electrodes (300 mm square, 1.1 mm thick) excluding the injection hole part
Liquid epoxy adhesive "DSA-001" (manufactured by Rodick) was applied, and this substrate and the other substrate on which 12.0 micron glass fiber spacers were dispersed were placed in a vacuum glove box, and the pressure inside the box was reduced. 20to
After setting rr, bond both substrates and create a cell,
A heat-resistant vinyl tape (1.5 cm × 0.5 cm) as the first sealing agent was attached to the injection hole portion.

After the pressure in the system was restored, the cell was placed in a clean oven to heat and cure the sealant.

Further, as the cell and the liquid crystal material, "RO
-TN-571 "(manufactured by Roche) was placed in a vacuum injecting device to reduce the pressure, and when the pressure reached 20 torr or less, the heat-resistant vinyl tape was peeled off.

45 minutes after the start of the pressure reduction in the vacuum injection tank, the injection hole of the cell was brought into contact with the liquid crystal material to start the injection, and the pressure was gradually restored. The pressure in the pouring tank at the start of pouring is
It was 0.05 torr.

Next, after heating this cell under normal pressure and applying "TB-3051" (manufactured by ThreeBond Co.) as a second sealing agent to the injection hole, the temperature is returned to room temperature and the sealing agent is injected into the injection hole. did. By irradiating this sealing portion with ultraviolet rays, the sealing agent was cured to obtain a liquid crystal device.

The obtained liquid crystal device had good adhesiveness and no bubbles were observed.

(Comparative Example 1) Two pieces of ITO having an alignment film
One of the glass substrates with electrodes (300 mm square, 1.1 mm thick) is used as a sealant on the peripheral part of the one substrate except the part after injection.
Liquid epoxy adhesive "DSA-001" (made by Rodick) is applied, and this substrate and the other substrate on which 12.0 micron glass fiber spacers are scattered are attached under normal pressure, and then in a pressure-bonding and curing jig. Then, the sealant was heated and cured in a clean oven while applying pressure to prepare a cell.

Further, as the cell and the liquid crystal material, "RO
-TN-571 "(manufactured by Roche) is placed in a vacuum injecting device to reduce the pressure, and after the start of the reducing pressure, the injection hole of the cell is brought into contact with the liquid crystal material to start the injection, and the injection is gradually restored. Pressed. The pressure in the injection tank at the start of injection is 0.05 torr.
Met.

Next, the cell is heated under normal pressure, "TB-3051" (manufactured by ThreeBond Co.) as a sealing agent is applied to the injection hole, and then the temperature is returned to room temperature to inject the sealing agent into the injection hole. did. By irradiating this sealing portion with ultraviolet rays, the sealing agent was cured to obtain a liquid crystal device.

The liquid crystal device thus obtained had good adhesiveness, but the presence of air bubbles was observed in the portion away from the injection hole.

(Example 2) In Example 1, "RO-
Instead of using "TN-571", 80% by weight of a liquid crystal composition (A) having the following composition, "Kayarad HX620" as a photopolymerizable composition (Nippon Kayaku Co., Ltd., caprolactone-modified hydroxypivalate neopentyl glycol) Diacrylate) 20% by weight and "IRGACURE 651" (manufactured by Ciba-Geigy, benzyl dimethyl ketal) 0.1% by weight as a polymerization initiator, and the dimming layer forming material is used in a cell or the like. Example 1 except that injection was performed while maintaining the temperature of the isotropic liquid state, then a sealing agent was applied to the injection holes, and the entire substrate was irradiated with ultraviolet rays.
Similarly to the above, a liquid crystal device having a light control layer made of a liquid crystal material and a transparent solid substance was obtained.

The liquid crystal composition (A) is

[0049]

[Chemical 1]

It is composed of

The obtained liquid crystal device had good adhesiveness and no bubbles were observed.

[0052]

According to the method of manufacturing a liquid crystal device of the present invention, a cell can be formed in a clean atmosphere, and the inside of the cell is sealed with a first sealing agent while maintaining a vacuum state.
Almost no foreign matter is mixed in, and it is not necessary to use a heavy object called a crimping jig.

Further, the time of the vacuum state in the vacuum injection tank can be shortened, and the time of the whole process can be shortened. Therefore, the manufacturing method is suitable for producing a large-sized liquid crystal device.

Claims (3)

[Claims] 1. A sealant is applied to the peripheral portion of one of the two substrates having an electrode layer, at least one of which is transparent, excluding the injection hole, and the sealant is applied to the substrate under vacuum. First step of defoaming and drying the substrate surface, (2) bonding this substrate and the other substrate together under vacuum to create a cell, and sealing the injection hole with a first sealing agent capable of peeling A second step of perforating, (3) a third step of recompressing and permanently curing the sealing agent under normal pressure, (4) peeling off the first sealing agent under vacuum,
After injecting the liquid crystal material into the cell, the second step is performed by irradiating the cell obtained in the fourth step of (5) the fourth step of applying the second sealing agent to the injection hole portion with the active light. A method for manufacturing a liquid crystal device, comprising a fifth step of curing a sealing agent. 2. (1) A sealant is applied to the peripheral portion of one of the two substrates having an electrode layer, at least one of which is transparent, excluding the injection hole, and the sealant is applied to the substrate under vacuum. First step of defoaming and drying the substrate surface, (2) bonding this substrate and the other substrate together under vacuum to create a cell, and sealing the injection hole with a first sealing agent capable of peeling A second step of perforating, (3) a third step of recompressing and permanently curing the sealing agent under normal pressure, (4) peeling off the first sealing agent under vacuum,
In the fourth step of injecting the light control layer constituting material containing the liquid crystal material, the polymerizable composition and the polymerization initiator into the cell and applying the second sealing agent to the injection hole portion, (5) the fourth step A liquid crystal having a fifth step of irradiating the obtained cell with an actinic ray to polymerize and cure the second pore-sealing agent and the polymerizable composition to form a light control layer composed of a liquid crystal material and a transparent solid substance. Device manufacturing method. 3. The method for producing a liquid crystal device according to claim 2, wherein the light control layer is a light control layer formed by forming a three-dimensional network structure of a transparent solid substance in a continuous layer of liquid crystal material.