JPH0325414A - Production of liquid crystal device - Google Patents

Abstract

PURPOSE:To prevent the generation of a deviation between two sheets of substrates by superposing one substrate onto the coating surface consisting of a specific light control layer constituting material from above, tentatively fixing these substrates, and curing a polymerizable compsn. overall while applying pressure to two sheets of the substrates from both sides thereof. CONSTITUTION:The light control layer constituting material contg. a liquid crystal material, the polymerizable compsn. and a polymn. initiator is applied on one substrate of two sheets of the substrates, which have patterned electrode layers and at least one of which is transparent. Another substrate is superposed on the coated surface from above and the substrates are registered. The polymerizable compsn. is spot-cured and tentatively fixed. Further, the entire part of the polymerizable compsn. is cured while the pressure is exerted to two sheets of the substrates from both sides thereof. Spacers for maintaining a spacing are usually preferably interposed between two sheets of the substrates in the same manner is for known liquid crystal devices. The liquid crystal device having the practicably sufficient accuracy in the registration of the patterned electrodes between the upper and lower substrates is efficiently obtd. in this way while the uniformity of the thickness of the light control layer is maintained.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a large-area liquid crystal device that is responsive to electric fields or heat.
The present invention relates to a method for manufacturing a liquid crystal device that enables display by time-division driving by forming a dimensional network polymer.

(Prior Art) A light control layer is supported between two substrates, at least one of which is transparent, having a buttered electrode layer, and the light control layer is made of a liquid crystal material and a transparent substrate. In the method for manufacturing a liquid crystal device, the liquid crystal material forms a continuous phase, and the transparent solid substance is present in the liquid crystal material in the form of particles or in the form of a three-dimensional book or twerk. After bonding and aligning the two boards, a misalignment may occur between the upper and lower boards during the move to the next crimping process or during the next crimping process.
There was a drawback that the positioning became inaccurate, resulting in poor yield.

(Problem to be Solved by the Invention) The present inventors have conducted research on a method for manufacturing a liquid crystal device that does not cause misalignment between two substrates after they are pasted together and aligned. As a result, we have arrived at the present invention.

(Means for solving the vA problem) The present invention provides the following methods: (a) a liquid crystal material; (b) a polymerizable composition; (c) The first step of applying the photochromic layer $1 material containing a polymerization initiator, and the other substrate made of the photochromic NI constituent material is overlapped and aligned from above the coated surface, and the polymerization is carried out. a second step in which the polymerizable composition is cured in spots and temporarily fixed between the two substrates, and a third step in which the polymerizable composition is entirely cured while applying pressure from both sides of the two substrates. a light control layer supported between said two substrates, said light control layer comprising a liquid crystal material and a transparent solid material, said liquid crystal material forming a continuous phase; This invention relates to a method for manufacturing a liquid crystal device in which a solid substance exists in the liquid crystal material in the form of particles or a three-dimensional network. The substrate may be a rigid material, such as glass, metal, etc., or a flexible material, such as plastic or film.

Two substrates can be placed facing each other with an appropriate distance between them. In addition, at least one of the layers must be transparent so that the light control layer sandwiched between the two layers can be seen from the outside world.

However, complete transparency is not required.

If this liquid crystal device is used to act on light passing from one side of the device to the other, both substrates are provided with suitable transparency. On this substrate, four turning electrodes (transparent or opaque as appropriate) are arranged on the entire surface or a portion of the casing. However, in the case of a flexible material such as a plastic film, the manufacturing method of the present invention can be used by fixing it to a rigid material such as glass or gold F4.

A light control layer consisting of a liquid crystal material and a transparent solid component is interposed between the two substrates. Note that it is usually desirable to interpose a spacer between the two substrates to maintain the distance, as in well-known liquid crystal devices.

As the spacer, various materials for liquid crystal cells such as mylar and alumina can be used, but square and double type glass fibers are suitable.

In order to obtain uniform spacing between the substrates, it is important to distribute the spacers uniformly on the substrate surface. For this purpose, ■ Suspend and disperse the spacers in the material constituting the light control layer so that the spacers do not separate or settle. In between, there is a method in which the suspension or dispersion is spread over the entire surface of the substrate, or (2) a method in which spacers are uniformly spread over the substrate or protrusions for spacers are provided on the substrate in advance. An example of a method for spraying in advance is to suspend the spacers in a low boiling point solvent such as ethanol, which has a low boiling point and relatively high viscosity, apply the suspension onto the substrate, and then dry the solvent. It is also effective to provide protrusions for spacers on the substrate surface using methods such as reeding or printing. Of course, the liquid crystal material does not need to be a single liquid crystal compound, and may be a mixture containing two or more types of liquid crystal compounds or substances other than liquid crystal compounds. Any material that can be recognized as such is acceptable, and those with positive dielectric anisotropy are preferred. Preferred liquid crystals to be used are nematic liquid crystal, smectic liquid crystal, black liquid crystal, and cholesteric liquid crystal. As a liquid crystal material, for example, 4-Elbenzoic acid 4'-f
f-substituted phenyl ester, 4-monosubstituted cyclohexanecarboxylic acid 4'-substituted 7-enyl ester, 4-monosubstituted cyclohexanecarboxylic acid 4'-monosubstituted biphenyl ester, 4-
(4-tert-substituted cyclohexanecarbonyloxy)benzoic acid 4'-monosubstituted phenyl ester, 4-(4-[9cyclohexyl)benzoic acid 4'-substituted phenyl ester, 4-(
4-[9cyclohexyl)benzoic acid 4'-monosubstituted cyclohexyl ester, 4-monosubstituted 4''-substituted biphenyl, 4-monosubstituted phenyl-4'-1f<substituted cyclohexane, 4-K
t-substituted 41-substituted terphenyl, 4-monosubstituted V phenyl 4'
-t-substituted cyclohexane, 2-(4-fi-substituted 7-enyl)
-5-substituted pirimiqunes, etc. Liquid crystal materials require a continuous phase between two substrates. If the proportion of the liquid crystal material is low, it is difficult to form a continuous phase. The ratio of the liquid crystal material to the light control layer components is preferably 6.
If the weight is 0 or more, it is better to use a 70 to 90 weight axe. Examples of the polymerizable composition include polymer-forming monomers or oligomers, as long as they form a three-dimensional network in the continuous phase of the liquid crystal material when cured. Examples of such polymeric monomer monomers include Eha,
Styrene, chlorostyrene, α-methylstyrene, divinylbenzene: Substituents include methyl, ethyl, globyl, butyl, amyl, 2-ethylhexyl, octyl, nonyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, methoxyethyl, butoxy Acrylates, methacrylates or fumarates having groups such as ethyl, 7-enoxyethyl, allyl, methallyl, glycisol, 2-hydroxyethyl, 2-hydroxyglobil, 3-chloro-2-hydroxyglobin, dimethylaminoethyl, diethylaminoethyl, etc.; Ethylene glycol, polyethylene glycol, clobylene glycol, polypropylene glycol, 1,3-7' ethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, trimethylolpronozene, glycerin and hyhentaerythrin}
Mono(meth)acrylates or poly(meth)acrylates such as vinyl acetate, vinyl butyrate or pinyl benzoate, acryloethryl, cetyl vinyl ether, limonene, cyclohexene, diallyl 7-thalerate, diallyl iso-7-thalerate, 2-3- or 4- vinylpyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethylacrylamide or N-
Hydroxyethyl methacrylamide and their alkyl ether compounds, 2 per mole of neopentyl glycol
di(meth)acrylate of diol obtained by adding mol or more of ethylene oxide or propylene oxide; di(meth)acrylate of triol obtained by adding 3 mol or more of ethylene oxide or glopylene oxide to 1 mol of trimethylolpropane; meta) acrylate,
Diol di(meth)acrylate obtained by adding 2 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A, 1 mole of 2-hydroxyethyl (meth)acrylate and 1 mole of phenyl isocyanate or savetyl isocyanate. Examples include poly(meth)acrylate of dipentaerythritol, trimethylolpropane triacrylate, tricyclodecane dimethylol diacrylate, polyethylene glycol diacrylate,
Particularly preferred are polypropylene glycol diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, and tris(acryloxyethyl)in cyanurate. Similarly, examples of polymer-forming oligomers include (1) (meth) bisphenol AM epoxy resin;
Epoxy (meth)acrylate obtained by esterifying acrylic acid, and in some cases long chain fatty acids such as coconut oil fatty acid, or its long chain fatty acid modified product, epoxy (meth)acrylate having a hydroxyl group and dibasic acid anhydride, Epoxy (meth)acrylates and modified products thereof, such as epoxy (meth)acrylates having a carpoxyl group obtained by adding tetrabasic acid dianhydride, trimeri anhydride, and tonic acid.

(2) Specification of British Patent No. 1,147,732 (Japanese Unexamined Patent Publication No. 51-37193 and Unexamined Japanese Patent Application No. 51-13
A terminal isocyanate compound obtained by reacting a diisocyanate compound and a polyol in advance as described in Japanese Patent Publication No. 8797) is further supplemented with β-hydroxyalkyl acrylate and/or methacrylate. Two or more acryloids in the molecule obtained by reaction■
Addition polymerizable compound having an xy group and/or a methacryloyloxy group. (3) Dibasic acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydroheptalic anhydride, tetrachlorophthalic anhydride, or het's acid anhydride as described in Japanese Patent Publication No. 47-3262. A linear polyester compound having a large number of acryloyloxy groups and/or methacryloyloxy groups obtained by open-ring polymerization of glycysol acrylate and/or glycidyl methacrylate. (4) a polyhydric alcohol having at least three esterifiable hydroxyl groups on adjacent carbon atoms, acrylic acid and/or methacrylic acid, and zocarponic acid as described in Japanese Publication No. 47-23661; 1. Polymerizable esters prepared by coesterification with dicarboxylic acids selected from the group consisting of carbonaceous acids and their anhydrides.

(5) Specification of British Patent No. 628,150, U.S. Patent No. 3,020,255@;b and monthly magazine “
Macromore Medium 1 Rules Volume 4, No. 5, No. 630-6
Melamine or penzoguanamine as described on page 32 (1971) with formaldehyde, methyl alcohol or β-hydroxyalkyl acrylate (
Polyacrylic (or polymethacrylic)-modified triazine resin obtained by reacting polyacrylic (or polymethacrylate) or the like.

(6) An unsaturated polyester resin obtained by reacting a glycidyl etherified polyhydroxy compound with acrylic acid or methacrylic acid as described in US Pat. No. 3,377,406. (7) The general formula described in U.S. Patent No. 3,455,801 and U.S. Patent No. 3,455,8 Q.2 (where R is carbon It represents a divalent saturated or unsaturated aliphatic hydrocarbon group having 2 to 10 atoms, R' represents two saturated aliphatic hydrocarbon groups having 2 to 10 carbon atoms, and RI represents a hydrogen atom or Represents a methyl group, n is 1 to 1
It is an integer of 4. ) A polyester compound having an acryloyloxy group or a methacryloyloxy group at both ends.

(8) General formula described in U.S. Patent No. 3,483,104 and U.S. Patent No. 3,470,079 (where A is 10 One or -
-, at least two in one molecule shall be one, R represents a divalent saturated aliphatic or unsaturated aliphatic hydrocarbon group, and RI represents a divalent saturated or unsaturated aliphatic hydrocarbon group. represents an aliphatic or loamy hydrocarbon, RI represents a hydrogen atom or an alkyl group, and n is an integer from 1 to 14.
) Diacrylic modification (or dimethacrylic modification) indicated by
Polyamide compound. (9) Diacrylic acid obtained by reacting a compound having carpoxyl groups at both ends obtained by reacting the general formula described in Japanese Patent Publication No. 48-37246 with glycidyl acrylate or glycidyl methacrylate. Modified (or dimethacrylic modified) polyester compound. 0 The general formula in the molecule as described in Japanese Patent Publication No. 48-12075, (where X represents a hydrogen atom or an acyl group, and B represents a divalent saturated or unsaturated aliphatic or cyclic hydrocarbon B' represents a divalent aliphatic hydrocarbon group, R2 represents a hydrogen atom or an alkyl group, A represents 101 or 1, and at least 2 in one molecule. is 1M, and n is an integer from 1 to 14.) Diacrylic modification (or methacrylic modification) represented by
Polyamide compound.

α0 Saturated or unsaturated dibasic acids or their anhydrides, as described in U.S. Pat. No. 3,485,732, or if necessary, diols (
Here, X represents an acyl group or a urethane group, and R represents H, CM, , CL or CN. ) A compound based on a (meth)acrylic copolymer having an unsaturated acid ester bond in the side chain and having a repeating unit. Among them, cabrolactone-modified hydroxypiparic acid ester neopentyl glycol diacrylate is particularly preferred. As a polymerization initiator, for example, 2-hydroxy-2-meth'F-ru-l-phenylpropan-1-one ("Dalokia 1173J" manufactured by Merck & Co., Ltd.
). 1-Hydroxycyclohexyl 7-enyl ketone (Chipa● is “Irgacure 184” manufactured by Iggy), 1-(4
-Inglobylphenyl)-2-hydroxy-2-methylpropan-1-one (Merck & Co., Ltd. “Darokichia 111”)
6J), penzyl dimethyl ketal (Chipa● is manufactured by Iggy Co., Ltd. “Irugaki, A651J”), 2-methyl-1-(4-
(Methylthio)phenyl]-2-morpholinozolopanone-1 (Irgacure 907J manufactured by Chipa-Gaiyi),
2. A mixture of 4-diethylthioxanthone (Kayacure DETXJ manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate (Kayacure EPA J manufactured by Nippon Kayaku Co., Ltd.), isoprobylthioxanthone (Ward Prequinn,
Examples include a mixture of ``Kantaki. It is particularly preferred in terms of compatibility with molecule-forming monomers or oligomers.

Chain transfer agents, photosensitizers, dyes, crosslinking agents, etc. can be appropriately used in combination with the light control layer constituting material as optional components, depending on the type of monomer oligomer, etc., and the performance of the desired liquid crystal device. .

In particular, the combined use of a chain transfer agent is extremely effective depending on the type of monomer or oligomer, and prevents the resin from becoming too highly crosslinked, thereby preventing... The liquid crystal material is made more responsive to electric fields and exhibits low voltage drive performance. Good examples of chain transfer agents are gutanedioldithiogropionate, pentaerythritol tetrakis (β-thioglopionate), triethylene glycol dimercagutan, and the like. The amount of chain transfer agent added varies depending on the type of heptamer or oligomer used, but if it is too small, the effect will be weak, and if it is too large, the opacity of the device will decrease and the contrast of the display will tend to deteriorate. I don't like it because it is. The effective amount is considered to be 0.05 to 30% by weight based on the monomer or oligomer, but 0.1 to 2% by weight.
0 weight Jim is suitable. In order to stack and align one substrate coated with the light control layer constituent material and the other, a stacking and alignment device generally used for manufacturing liquid crystal empty cells can be used. However, since the material constituting the light control layer is interposed over the entire surface between the substrates, the upper and lower substrates often become misaligned after overlapping and positioning.

The present inventors have discovered that it is possible to prevent misalignment of the upper and lower substrates by curing the polymerizable composition in the porcelain layer constituent material in spots in that state after superimposing and aligning the substrates. invention has been achieved.

By controlling the size and number of spots, it is possible to temporarily fix the spots and to compress the spots to the desired substrate spacing during the next process of crimping. In addition, since the same material for the light control layer is used in the spot-cured part according to the present invention and the part to be cured in the next process, by making the spot-curing conditions and the curing conditions in the next process the same, the spot-cured part and the part to be cured in the next step can be cured. Parallax at the border with other hardened parts can be made invisible.

The size of the spot can be appropriately determined depending on the concentration of the polymer, hardness, adhesion to the substrate, and thickness of the spacing between the substrates.

If the polymer has good contact with the substrate and is hard, the spot size may be small, but if the opposite is the case, the spot size should be increased. Approximately 0. Spots with a diameter of 2 to 20 m are suitable.・
The number of spots can be determined as appropriate depending on the size of the substrate and the thickness of the spacing between the substrates, and is generally 100cIA/1cm.
It is preferable to provide ~2 pieces.

In the case of thermal polymerization, methods such as heat beams and lasers can be used to cure spots, but in consideration of curing time, methods using electron beams and ultraviolet rays are preferable. The method using ultraviolet rays is particularly suitable.

In order to cure the material in spots with ultraviolet rays, a normal ultraviolet irradiation device can be used by shielding the substrate surface other than the spot portion, but it is preferable to use an ultraviolet spot irradiation device using an optical fiber or the like. That is, a multi-branch light guide may be attached to the ultraviolet ray irradiation device to simultaneously irradiate multiple spots with ultraviolet rays, or a single spot may be irradiated with ultraviolet rays from the ultraviolet ray spot irradiator. After that, you can sequentially irradiate other spots with ultraviolet light. The pressure applied to the substrates is determined by the properties of the material forming the light control layer interposed between the substrates. In particular, the magnitude of the pressure is influenced by the viscosity of the material constituting the light control layer. The higher the viscosity of the bottle, the greater the pressure required. Although lower pressures are advantageous for operation, various methods of reducing viscosity can be used for this purpose. For example, it is effective to raise the temperature or to add a low molecular weight monomacrylate with low polarity to the material constituting the light control layer within a range that does not impede the performance of the liquid crystal device. It is important to apply pressure evenly over the entire surface of the substrate, and in this way nine different machines can be used.

Further, in the method for manufacturing a liquid crystal device of the present invention, the entire surface of the substrate is brought into contact with the coated surface from the time when the substrates stacked from above the coated surface made of the light control layer constituent material partially contact the core coated surface. By intermittently bringing the substrate close to the coating surface during this period, it is possible to effectively prevent air bubbles from entering the light control layer. Furthermore, it is particularly effective to bring the substrate to be superimposed on the coated surface made of the material constituting the light control layer close to the coated surface for 1 to 5 seconds at a rate of 1 to 50 μm/sec every 1 to 10 seconds.

When setting these time intervals and speeds, it is desirable to take work efficiency into consideration and to make them as short or fast as possible. The method for polymerizing and curing the polymerizable composition may be any commonly known curing method, such as thermal polymerization, radiation polymerization, electron beam polymerization, etc., but a polymerization and curing method using ultraviolet irradiation is preferred.

In the ultraviolet polymerization curing method, (1) setting the curing temperature to a higher temperature than the phase transition temperature of the liquid crystal phase of the mixed solution and (2) depending on the UV absorption wavelength of the mixed solution and the polymerizable composition; In addition, by irradiating strong ultraviolet rays in a linear pattern with no difference in polymerizability depending on the thickness of the spacing between the substrates, it is possible to form a polymer in the continuous phase of the liquid crystal material that is present between the substrates. By uniformizing and controlling the mesh size of the three-dimensional network of transparent solid components, we manufacture a liquid crystal display element with clear threshold voltage and steepness, that is, a liquid crystal device capable of time-division drive display. You can.

(Function) According to the method for manufacturing a liquid crystal device of the present invention, the light control layer construction material is applied to one substrate, and the polymerizable composition is spot-cured at the time when the other substrate is superimposed and aligned. ,
Temporary fixing prevents misalignment during the next process of crimping and curing, making it possible to perform crimping and curing while maintaining highly accurate positioning. That is, it is possible to provide a high-performance liquid crystal device in which polymers are dispersed in a three-dimensional network in a liquid crystal without misalignment between the upper and lower substrates of the two terminal electrodes. Furthermore, by using a substrate having matrix and matrix electrodes, it is possible to provide a high-performance liquid crystal device that can accurately perform time-division driving.

(Example) Glass fiber spacer (average fiber diameter 1
2. On ) 0. 2 1 to 100
A solution suspended in cc is sprinkled onto a glass substrate having a 20 x 20 cm square ITO matrix and electrode. After spraying, ethanol is evaporated to dryness.

Liquid crystal composition (4) Transition temperature 68.5°C (N-I) -25
°C (C-N) no÷1.5 3 3 2 Viscosity at 0 °C 59a. p
．． jn=0.2 5 4! ! Electricity translation direction AM-
269 Next, 80% by weight of liquid crystal composition (A) was used as the liquid crystal material, 19.6% by weight of polypropylene glycol-modified pentyl glycol diacrylate (C-9003 manufactured by Sartomer Co., Ltd.) as the polymerizable compound, and 2% by weight as the polymerization initiator.
Hydroxy-2-methyl-1-7-enyl-glono-1
-On 0. The material constituting the light control layer consisting of 4 layers of IS is applied to the substrate surface in an isotropic liquid state at 35°C. Next, the other matrix and the glass substrate having the electrodes are laminated together carefully without entrainment of air bubbles, and alignment is performed using an alignment device. After the alignment was completed, UV rays were irradiated near the circumferential edge of the substrate using an ultraviolet spot irradiation device so that each spot had a diameter of 811 mm to perform spot curing. The UV irradiation at this time is intensity 6
It was 0 mW/1 for 15 seconds. When curing was performed in spots at four points, no shearing occurred between the upper and lower substrates even when force was applied. Next, the upper and lower substrates were crimped using a crimping jig while applying pressure at 35°C. The applied pressure and time were 0.26 kg/aA, a minute. In that state, pass through the transparent glass surface on the opposite side of the pressurized side.
When irradiated with ultraviolet light at mW/ad intensity for 15 seconds, a sufficiently uniform cloudy device was obtained. The positional deviation of the upper and lower electrode substrates of the obtained liquid crystal device was 10
The thickness of the light control layer in μm is 12.3±0. 5μ
The thickness of the part that was uniform with m and fixed in the form of a b spot was within the same thickness range. The positional deviation of devices fabricated in the same way was less than 25 μm, and the desired thickness of the light control layer could be obtained.

(Comparative Example) A liquid crystal device was produced in the same manner as in the above example except that spot curing was not performed in the above example. In this case, the positional deviation between the upper and lower substrates was 108 μm. It is possible to efficiently provide liquid crystal devices whose positioning accuracy is sufficient for practical use. Therefore, by using the method of manufacturing a liquid crystal device of the present invention, a liquid crystal device capable of advanced display such as time-division drive, which is used not only for viewing-blocking screens and lighting control curtains, but also for large display boards for characters and graphics, can be produced. It can be manufactured efficiently.

Claims (1)

[Claims] 1. On one of two substrates, at least one of which is transparent, having a patterned electrode layer, (a) a liquid crystal material, (b) a polymerizable composition, and (c) a polymerization initiator. The first step is to apply the light control layer constituent material containing the light control layer constituent material, and the other substrate is placed and aligned from above the coated surface made of the light control layer constituent material, and the polymerizable composition is cured in spots. a second step in which the two substrates are temporarily fixed together; and a third step in which the polymerizable composition is completely cured while applying pressure from both sides of the two substrates. a light control layer supported therebetween, said light control layer comprising a liquid crystal material and a transparent solid component, said liquid crystal material forming a continuous phase, and said transparent solid material being particulate within said liquid crystal material. Or a method for manufacturing a liquid crystal device that exists in the form of a three-dimensional network. 2. The method for manufacturing a liquid crystal device according to claim 1, wherein the polymerizable composition is an ultraviolet curable resin composition. 3. The method for manufacturing a liquid crystal device according to claim 1 or 2, wherein the spot-like curing is performed by ultraviolet irradiation means. 4. The method of manufacturing a liquid crystal device according to claim 1, 2 or 3, wherein an ultraviolet spot irradiation device is used for spot partial curing. 5. Claim 1 in which a liquid crystal material exhibiting positive dielectric anisotropy is used.
, 2, 3 or 4, the method for manufacturing a liquid crystal device. 6. The method for manufacturing a liquid crystal device according to claim 1, 2, 3, 4 or 5, wherein the liquid crystal material accounts for 60% by weight or more of the light control layer constituting material. 7. The liquid crystal according to claim 1, 2, 3, 4, 5, or 6, wherein the curing temperature condition of the polymerizable composition is higher than the phase transition temperature of the liquid crystal material from a liquid crystal phase to an isotropic liquid phase. Method of manufacturing the device.