JP4796751B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

  The present invention relates to a method of manufacturing a liquid crystal display device obtained by arranging a spacer on a substrate by an ink jet method.

  Liquid crystal display devices are currently widely used in personal computers, portable electronic devices, and the like. In general, as shown in FIG. 1, the liquid crystal display device has two transparent electrodes in which a transparent electrode 3, an alignment film 9, a color filter 4, a black matrix 5 and the like are formed on the inner side and a polarizing plate 2 is disposed on the outer side. The substrate 1 is disposed so as to face each other with a sealant 10 disposed around these substrates, and the liquid crystal 7 is sealed in the formed gap. In this liquid crystal display device, the spacer 8 regulates the distance between the two transparent substrates 1 to maintain an appropriate liquid crystal layer thickness (cell gap).

  In a conventional method for manufacturing a liquid crystal display device, spacers are randomly and uniformly distributed on a substrate on which a pixel electrode is formed. Therefore, as shown in FIG. Spacers are also arranged in (region). The spacer is generally formed of synthetic resin, glass, or the like, and when the spacer is disposed on the pixel electrode, the spacer portion leaks light due to a biasing action. Further, the liquid crystal alignment on the spacer surface is disturbed, so that light leakage occurs, the contrast and color tone are lowered, and the display quality is deteriorated. In the TFT liquid crystal display device, the TFT element is arranged on the substrate. However, when the spacer is arranged on the element, there is a serious problem that the element is damaged when pressure is applied to the substrate. .

In order to solve the problems associated with the random dispersion of the spacers, it has been proposed to dispose the spacers under the light shielding layer (the portion that defines the pixel region). As a method of arranging the spacer only at a specific position in this way, for example, a method of spraying the spacer through the mask after matching the position where the mask having the opening is to be arranged (see Patent Document 1). A method is disclosed in which a spacer is electrically adsorbed and then transferred to a transparent substrate (see Patent Document 2).
However, these methods have a problem in that the mask and the photoconductor are in direct contact with the substrate, thereby damaging the alignment film on the substrate and reducing the image quality of the liquid crystal display.

In addition, a method for manufacturing a liquid crystal display device is disclosed in which a voltage is applied to pixel electrodes on a substrate and dispersed spacers are dispersed by electrostatic repulsion (see Patent Document 3). .)
However, this method requires an electrode in accordance with the pattern to be arranged, so that it was impossible to arrange it completely at an arbitrary position.

On the other hand, a method of disposing spacers by an ink jet method is disclosed (see Patent Document 4). This method is effective because it does not come into contact with the substrate itself as described above, and the spacer can be arranged in an arbitrary pattern at an arbitrary position.
However, since the spacer particle dispersion to be discharged contains spacer particles of about 1 to 10 μm, in order to discharge straightly, the nozzle diameter of the inkjet head has to be increased. Even if the droplets ejected onto the substrate become large and are ejected aiming at the light shielding region, the droplets protrude from the light shielding region to the pixel region, and the spacers are arranged up to the transmission region. There was a problem that the quality of the liquid crystal could not be improved sufficiently.

Japanese Patent Laid-Open No. 4-198919 JP-A-6-258647 JP-A-10-339878 JP-A-57-58124

  SUMMARY OF THE INVENTION An object of the present invention is to provide a manufacturing method for manufacturing a liquid crystal display device having a high display quality without any light leakage by the spacer by accurately arranging spacers on a non-display portion of a liquid crystal display device substrate by an ink jet method. It is a thing.

According to the first aspect of the present invention, in a liquid crystal display device comprising a pixel region arranged according to a certain pattern and a light-shielding region that defines the pixel region, a spacer particle dispersion liquid in which spacer particles are dispersed using an ink jet device is provided. A substrate in which spacer particles are arranged in a region corresponding to a light shielding region of a substrate on which a pixel is formed or a region in which a pixel is not formed or a region corresponding to a light shielding region of a substrate on which a pixel is not formed, and a substrate on which no spacer particle is arranged A method of manufacturing a liquid crystal display device opposed to each other through spacer particles arranged in the light-shielding region or a region corresponding to the light-shielding region, wherein the spacer in the spacer dispersion liquid is charged by an inkjet method It is a manufacturing method of a liquid crystal display device.
According to a second aspect of the present invention, there is provided an ink-jet liquid crystal display device according to the first aspect, wherein there is a wiring material made of a material that can be charged adjacent to a specific position corresponding to a region defining the pixel region. It is a manufacturing method.
A third aspect of the invention is a method for manufacturing a liquid crystal display device according to the second aspect of the invention, wherein the wiring material made of a chargeable material is charged to a charge opposite to that of the charged spacer.

  The spacer particles used in the present invention are not particularly limited, and may be inorganic particles such as silica particles or organic polymer particles. Among them, the organic polymer particles have an appropriate hardness that does not damage the alignment film formed on the substrate of the liquid crystal display device, and can easily follow the change in thickness due to thermal expansion and contraction. It is preferably used because it has the advantage that the movement of the spacer is relatively small.

  The composition of the organic polymer is not particularly limited, and usually a monofunctional monomer having one vinyl group and a polyfunctional monomer having two or more vinyl groups are used in combination for strength and the like. In this case, the ratio of the monofunctional monomer to the polyfunctional monomer is not particularly limited, and is appropriately adjusted depending on the strength and hardness required for the obtained organic polymer particles.

  Examples of the monofunctional monomer include styrene derivatives such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and chloromethylstyrene; vinyl chlorides; vinyl esters such as vinyl acetate and vinyl propionate; acrylonitrile and the like. Unsaturated nitriles; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol (meth) acrylate, tri And (meth) acrylic acid ester derivatives such as fluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, and cyclohexyl (meth) acrylate. These monofunctional monomers may be used alone or in combination of two or more.

  Examples of the polyfunctional monomer include divinylbenzene, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolpropanetetra (meta ) Acrylate, diallyl phthalate and its isomers, triallyl isocyanurate and its derivatives, trimethylolpropane tri (meth) acrylate and its derivatives, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (Meth) acrylate, polyethylene glycol di (meth) acrylate such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, etc. Ripropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 2,2-bis [4- (methacryl 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane di (meth) acrylate such as loxyethoxy) phenyl] propanedi (meth) acrylate, 2,2-hydrogenated bis [4- (acryloxypolyethoxy) Phenyl] propane di (meth) acrylate, 2,2-bis [4- (acryloxyethoxypolypropoxy) phenyl] propane di (meth) acrylate, and the like. These polyfunctional monomers may be used alone or in combination of two or more.

A monomer having a hydrophilic group may be used as the monofunctional or polyfunctional monomer.
Examples of the hydrophilic group include a hydroxyl group, a carboxyl group, a sulfonyl group, a phosphonyl group, an amino group, an amide group, an ether group, a thiol group, and a thioether group. Examples of the monomer having a hydrophilic group include 2-hydroxyethyl (meth) acrylate, 1,4-hydroxybutyl (meth) acrylate, (poly) caprolactone-modified hydroxyethyl (meth) acrylate, allyl alcohol, glycerin monoallyl Monomers having a hydroxyl group such as ether; acrylic acids such as (meth) acrylic acid, α-ethylacrylic acid, crotonic acid, and their α- or β-alkyl derivatives; fumaric acid, maleic acid, citraconic acid, Unsaturated dicarboxylic acids such as itaconic acid; monomers having a carboxyl group such as mono 2- (meth) acryloyloxyethyl ester derivatives of these unsaturated dicarboxylic acids; t-butylacrylamide sulfonic acid, styrenesulfonic acid, 2-acrylamide Such as 2-methylpropanesulfonic acid Monomers having a nyl group; Monomers having a phosphonyl group such as vinyl phosphate and 2- (meth) acryloyloxyethyl phosphate; Amino groups such as amines having an acryloyl group such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate A compound having both a hydroxyl group and an ether group such as (poly) ethylene glycol (meth) acrylate and (poly) propylene glycol (meth) acrylate; a terminal alkyl ether of (poly) ethylene glycol (meth) acrylate, Monomers having an ether group such as (poly) propylene glycol (meth) acrylate terminal alkyl ether, tetrahydrofurfuryl (meth) acrylate; (meth) acrylamide, methylol (meth) acrylamid Or a monomer containing an amide group such as vinyl pyrrolidone.

The method for producing particles by polymerizing the monomer is not particularly limited, and examples thereof include suspension polymerization method, seed polymerization method, dispersion polymerization method and the like, and any method may be adopted.
In the suspension polymerization method, the particle size distribution of the obtained particles is relatively wide and polydispersed particles can be obtained. Therefore, when used as a spacer, classification is performed to have a desired particle size or particle size distribution. It is suitably used when obtaining various types of particles. On the other hand, seed polymerization and dispersion polymerization can be suitably used when producing a large amount of particles having a specific particle diameter because monodispersed particles can be obtained without going through a classification step.

The suspension polymerization method is a method in which a monomer composition comprising a monomer and a polymerization initiator is dispersed and polymerized in a dispersion medium so as to have a target particle size. As the dispersion medium used for the suspension polymerization, a solution obtained by adding a dispersion stabilizer to water is usually used. Examples of the dispersion stabilizer include polymers soluble in the medium, such as polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene oxide. Nonionic or ionic surfactants are also used as appropriate.
The polymerization conditions vary depending on the polymerization initiator and the type of monomer, but the polymerization temperature is usually 50 to 80 ° C. and the polymerization time is 3 to 24 hours.

The seed polymerization method is a polymerization method in which a monodisperse seed particle synthesized by soap-free polymerization or emulsion polymerization is further absorbed with a polymerizable monomer to expand to a target particle diameter. The organic monomer used for the seed particles is not particularly limited, and the above-mentioned monomers are used. The composition of the seed particles is a monomer component during seed polymerization in order to suppress phase separation during seed polymerization. And styrene and its derivatives are preferred from the standpoint of monodispersity of the particle distribution. Since the particle size distribution of the seed particles is reflected in the particle size distribution after seed polymerization, it is preferably monodispersed as much as possible, and is preferably 5% or less as the Cv value. As described above, phase separation from the seed particles is likely to occur during seed polymerization. Therefore, the monomer absorbed during seed polymerization is preferably as close as possible to the seed particle composition. If the seed particles are styrene, aromatic divinyl is used. In the case of a monomer or acrylic, it is preferable to polymerize by absorbing an acrylic polyfunctional vinyl monomer.
In the seed polymerization method, a dispersion stabilizer can be used as necessary. The dispersion stabilizer is a polymer that is soluble in a medium, and examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene oxide. Nonionic or ionic surfactants are also used as appropriate.
In the seed polymerization method, it is desirable to add 20 to 100 parts by weight of monomer with respect to 1 part by weight of seed particles. When the monomer is less than 20 parts by weight, the breaking strength of the obtained particles may be insufficient. When the monomer exceeds 100 parts by weight, the particle size distribution is wide due to particle coalescence during seed polymerization. It tends to be unfavorable.

  In the dispersion polymerization method, polymerization is performed in a poor solvent system in which the monomer is dissolved but the generated polymer is not dissolved, and the resulting polymer is precipitated in a particle shape by adding a polymer dispersion stabilizer to this system. Is the method. In general, when the crosslinking component is polymerized by dispersion polymerization, the particles tend to aggregate and it is difficult to stably obtain monodispersed crosslinked particles. However, by selecting the conditions, the monomer containing the crosslinking component can be polymerized. Is possible.

  The medium used for the seed polymerization should be appropriately determined depending on the polymerizable monomer to be used, and generally suitable organic solvents include alcohols, cellosolves, ketones or hydrocarbons. Furthermore, these can be used alone or as a mixed solvent with other organic solvents, water, or the like that are compatible with each other, but is not limited thereto. For example, acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide, alcohols such as ethyl acetate, methanol, ethanol, propanol, cellosolves such as methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, methyl butyl ketone, 2-butanone, etc. The following ketones can be listed.

  In the polymerization, a polymerization initiator is used, and is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, benzoyl peroxide, benzoyl orthomethoxybenzoate, 3,5,5-trimethylhexanoyl peroxide, Organic peroxides such as t-butylperoxy-2-ethylhexanoate and di-t-butylperoxide, azobisisobutyronitrile, azobiscyclohexacarbonitrile, azobis (2,4-dimethylvaleronitrile) An azo compound such as) is preferably used. In general, the amount of the polymerization initiator used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

Since the spacer particles used in the present invention are used as a gap material of a display element, a certain strength is required. As an index indicating the compressive strength of the particles, when expressed by a compressive elastic modulus (10% K value) when the diameter of the particles is displaced by 10%, 2000 to 15000 MPa is preferable as the gap material of the display element. If the pressure is less than 2000 MPa, the spacer is deformed by a pressing pressure when assembling the display element, and an appropriate gap is hardly generated. If the pressure is higher than 15000 MPa, the display film may be damaged due to damage to the alignment film on the substrate when incorporated in the display element.
The compression elastic modulus (10% K value) of the particles is a value determined by the following method.
That is, it was measured according to Japanese Patent Publication No. 6-503180, and 10% of the particles were measured with a smooth end face of a diamond column having a diameter of 50 μm using a micro compression tester (PCT-200, manufactured by Shimadzu Corporation). It is obtained from the load for distorting.

  The spacer particles obtained by the above method may be colored and used for improving the contrast of the display element. Colored particles include, for example, particles treated with carbon black, disperse dyes, acid dyes, basic dyes, metal oxides, etc., and an organic film is formed on the surface of the particles and decomposed or carbonized at high temperatures. And colored particles. In addition, when the material itself which forms particle | grains has a color, you may use as it is, without coloring.

In the present invention, the spacer particles are subjected to a chargeable process.
The chargeable treatment is treatment in which the spacer particles have some potential even in the spacer dispersion liquid, and this potential (charge) can be measured by an existing method such as a zeta potential measuring device.
Examples of a method for performing chargeable treatment include a method in which a charge control agent is contained in spacer particles, a method in which spacer particles are produced from a monomer containing a monomer that is easily charged, and a surface in which spacer particles can be charged. The method of processing etc. are mentioned.
In addition, since the spacer particles can be charged in this manner, the dispersibility and dispersion stability of the spacer particles in the spacer dispersion liquid are improved, and the spacers are located in the vicinity of the wiring portion (step) portion due to the electrophoretic effect at the time of dispersion. It becomes easy to gather together.

The charge control agent may be added by a method in which the charge control agent is allowed to coexist when the spacer particles are polymerized and are contained in the spacer particles, or when the spacer particles are polymerized, the monomer constituting the spacer particles. A charge control agent having a functional group copolymerizable with the monomer constituting the spacer particles to be contained in the spacer particles, and a monomer used for surface modification in the surface modification of the spacer particles described later A charge control agent having a functional group that can be copolymerized with the surface modification layer is copolymerized and contained in the surface modification layer, or the surface modification layer or charged particles having a functional group opposite to the surface functional group of the spacer particle are reacted to be contained on the surface. And the like.
As the charge control agent, compounds as described in JP-A-2002-148865 can be used. Specifically, for example, organometallic compounds, chelate compounds, monoazo dye metal compounds, acetylacetone metal compounds, aromatic hydroxyl carboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, anhydrides, esters, bisphenols, etc. And phenol derivatives. Urea derivatives, metal-containing salicylic acid compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylic-sulfonic acid copolymers, non-metals Carboxylic acid compounds, modified products with nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs thereof Onium salts such as phosphonium salts and their lake pigments, triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, Felici ), Metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, diorganotin borates such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate, etc. Is mentioned. These charge control agents may be used alone or in combination of two or more.
The spacer particles containing the charge control agent can be charged by positively or negatively charging the spacer particles with respect to the surrounding environment by appropriately selecting an appropriate charge control agent from among the antistatic control agents. You can make it.

  When manufacturing spacer particles, as a method for selecting a monomer appropriately from monomers including monomers that are easily charged, the monomer described in the section for manufacturing spacer particles has a hydrophilic functional group. The method of using things in combination is given. By appropriately selecting an appropriate monomer from these monomers having a hydrophilic functional group, the spacer particles can be charged positively or negatively with respect to the surrounding environment. .

  As a method for modifying the surface of the spacer particles, as disclosed in JP-A-1-247154, a method for modifying the surface by depositing a resin on the spacer surface, as disclosed in JP-A-9-11915. The surface modification is performed by graft polymerization on the spacer surface as described in JP-A-11-223818 and Japanese Patent Application No. 2002-102848. Although a method etc. are mentioned, When performing these, the method in which a spacer particle is electrically charged is selected suitably.

As a surface modification method, a method of forming a surface layer chemically bonded to the particle surface is preferable because there are few problems of peeling of the surface layer and elution into the liquid crystal in the cell of the liquid crystal display device. In particular, the method described in JP-A-9-113915 is a method in which an oxidizing agent is reacted with particles having a reducing group on the surface, radicals are generated on the particle surface, and graft polymerization is performed on the surface. This is preferable because a surface layer having a sufficient thickness can be formed. In this method, for the charging treatment, a monomer having a hydrophilic functional group is used in combination as a monomer when graft polymerization is performed.
Further, by performing the surface treatment in this manner, there is an effect that the adhesion of the spacer particles to the substrate is increased, and if the monomer to be used is appropriately selected, the alignment of the liquid crystal in the liquid crystal display body is not disturbed.

The spacer dispersion used in the present invention is not particularly limited as long as the above-described spacer particles are dispersed in a medium in which the spacer particles can be dispersed.
As the medium of the spacer dispersion liquid, for example, various solvents that are liquid at the temperature discharged from the head are used. Of these, a water-soluble or hydrophilic solvent is preferable. In addition, since the heads of some ink jet devices are made for aqueous media, when these heads are used, a solvent having a strong hydrophobic property may cause the member constituting the head to be affected by the solvent or to adhere the member. It is not preferable because a part of the adhesive is dissolved.

  Examples of the water-soluble or hydrophilic solvent include water, ethanol, n-propanol, 2-propanol, 1-butanol, 2-butanol, 1-hexanol, 1-methoxy-2-propanol, furfuryl alcohol, tetrahydro Monoalcohols such as furfuryl alcohol, ethylene glycol multimers such as ethylene glycol, diethylene glycol recall, triethylene glycol and tetraethylene glycol; large amounts of propylene glycol such as propylene glycol, dipropylene glycol, tripropylene glycol and tetrapropylene glycol Body: lower monoalkyl ethers of glycols such as monomethyl ether, monoethyl ether, monoisopropyl ether, monopropyl ether, monobutyl ether Lower alkyl ethers such as dimethyl ether, diethyl ether, diisopropyl ether and dipropyl ether; alkyl esters such as monoacetate and diacetate, 1,3-propanediol, 1,2-butanediol and 1,3-butane Diol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 3-hexene-2,5-diol, 1,5-pentanediol, 2,4-pentanediol, 2-methyl-2, Diols such as 4-pentanediol, 2,5-hexanediol, 1,6-hexanediol, neopentylglycol, ether derivatives of diols, acetate derivatives of diols, glycerin, 1,2,4, -butanetriol 1,2,6-hexanetriol, 1,2,5, -pen Ntriol, trimethylolpropane, trimethylolethane, pentaerythritol and other polyhydric alcohols or ether derivatives thereof, acetate derivatives, dimethyl sulfoxide, thiodiglycol, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, r-butyrolactone, 1,3-dimethyl-2-imidazolidine, sulfolane, formamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylformamide, acetamide, N-methylacetamide, α-terpineol, ethylene Carbonate, propylene carbonate, bis-β-hydroxyethylsulfone, bis-β-hydroxyethylurea, N, N-diethylethanolamine, abietinol, diacetone alcohol, urea, etc. It is below.

As the spacer dispersion liquid, a spacer dispersion liquid having a receding contact angle (θr) with respect to the substrate to be discharged of 5 degrees or more is preferably used.
If the receding contact angle is 5 degrees or more, the droplet of the spacer dispersion liquid that has landed on the substrate dries and shrinks toward the center, and at least one spacer contained in the droplet is the center of the droplet. It becomes possible to gather near. As a result, the movement of the pacer is more likely to occur as will be described later, and the spacer placement accuracy is further improved.
When the receding contact angle (θr) is less than 5 degrees, the droplet dries around the center (landing center) where the droplet landed on the substrate, the droplet diameter decreases, and the spacer It's harder for people to get to the center.
Here, the receding contact angle is the landing diameter when the spacer dispersion liquid droplet placed on the substrate is first placed on the substrate after it is placed on the substrate and dried. The contact angle shown when it starts to become smaller (when the droplet starts to shrink) or the contact angle when 80 to 95% by weight of the volatile components of the droplet volatilizes.

As a method for setting the receding contact angle to be 5 degrees or more, there are a method for adjusting the composition of the dispersion medium of the spacer dispersion liquid described above, and a method for adjusting the surface of the substrate.
In order to adjust the composition of the dispersion medium of the spacer dispersion liquid, a medium having a receding contact angle of 5 degrees or more may be used alone, or two or more kinds of media may be mixed and used. It is preferable to use a mixture of the above because it is easy to adjust the dispersibility of the spacer, the workability of the spacer dispersion, the drying speed, and the like.

  When two or more solvents are mixed and used as the spacer dispersion liquid, they may be mixed so that the receding contact angle (θr) of the solvent having the highest boiling point is 5 degrees or more. preferable. If the receding contact angle (θr) of the solvent with the highest boiling point is less than 5 degrees, the droplet diameter becomes large in the latter stage of drying (the droplet spreads on the substrate), and the spacer is landed on the substrate. It becomes difficult to gather in the center.

In the present invention, the spacer dispersion medium preferably contains a solvent having a boiling point of less than 100 ° C. More preferably, the organic solvent has a boiling point of 70 ° C. or higher and lower than 100 ° C.
The boiling point in the present invention refers to the boiling point under the condition of 1 atm. Examples of the solvent having a boiling point of less than 100 ° C. include lower monoalcohols such as ethanol, n-propanol and 2-propanol, acetone. Etc. are preferably used.
When drying the solvent by spraying the spacer dispersion liquid, if the medium comes into contact with the alignment film at a high temperature, the alignment film is contaminated and the display image quality of the liquid crystal display device is impaired. By using a solvent of less than 100 ° C., the drying temperature can be lowered, so that the alignment film is not contaminated. The ratio of the solvent having a boiling point of less than 100 ° C. in the medium is preferably 5 to 80% by weight. If it is less than 10% by weight, the drying rate as a dispersion at a relatively low drying temperature applied in the present invention is slow, and production efficiency is lowered, which is not preferable. On the other hand, if it exceeds 80% by weight, the spacer dispersion near the nozzles of the ink jet device is likely to be dried, and the ink jet discharge property is impaired. Become.
The solvent mixed with the solvent having a boiling point of less than 100 ° C. is a solvent having a boiling point of 100 ° C. or higher, preferably water or a solvent having a boiling point of 150 ° C. or higher, more preferably a boiling point of 150 ° C. or higher and 200 ° C. The following solvents are added:

  Specific examples of the solvent having a boiling point of 150 ° C. or higher include lower alcohol ethers such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol, and dimethyl ether. Such a solvent prevents the spacer dispersion liquid from being excessively dried near the nozzles of the ink jet device and lowers the discharge accuracy, and suppresses the generation of aggregated particles when the spacer dispersion liquid is produced or dried in the tank. The ratio of the solvent having a boiling point of 150 ° C. or higher in the medium is preferably 0.1 to 95% by weight, and more preferably 0.2 to 90% by weight. If it is less than 0.1% by weight, it is not preferable because the discharge accuracy is lowered and the generation of aggregated particles is likely to occur due to drying of the dispersion liquid as described above. If it exceeds 95% by weight or the boiling point exceeds 200 ° C., not only the drying time is remarkably reduced but the efficiency is lowered, and the display image quality of the liquid crystal display device is liable to deteriorate due to contamination of the alignment film.

The solvent having a boiling point of less than 100 ° C. preferably has a surface tension at 20 ° C. of 25 mN / m or less, and a solvent having a boiling point of 100 ° C. or higher at 20 ° C. The surface tension is preferably 30 mN / m or more.
A general inkjet device exhibits good ejection accuracy when the surface tension of the liquid to be ejected is 30 to 50 mN / m. In addition, a higher surface tension of the dispersed droplets discharged onto the substrate is suitable for moving the spacer during the drying process.
When a solvent having a boiling point of less than 100 ° C. and a surface tension of 25 mN / m or less is mixed, the surface tension of the spacer dispersion liquid can be relatively lowered during discharge, so that good discharge accuracy can be obtained. By mixing a solvent having a boiling point of 150 ° C. or more and a surface tension of 30 mN / m or more, it becomes easy to set the receding contact angle to 5 degrees or more. That is, after the spacer dispersion liquid droplets have landed on the substrate, the low surface tension solvent having a boiling point of less than 100 ° C. is volatilized first, and the surface tension of the remaining dispersion liquid increases, toward the center of the landing point. This is preferable because the movement of the spacer tends to occur.

  In the process leading to the present invention, the receding contact angle tends to be smaller than the so-called contact angle (the initial contact angle when the droplet is placed on the substrate, which is usually called the contact angle in most cases). I knew that there was. This is because the initial contact angle is the contact angle of the droplets on the substrate surface that is not in contact with the solvent constituting the spacer dispersion liquid, whereas the receding contact angle is the solvent constituting the spacer dispersion liquid. This is presumably because the contact angle of the droplet with respect to the substrate on the surface of the substrate after contacting the substrate. That is, when the receding contact angle is significantly lower than the initial contact angle, it indicates that the alignment film is damaged by those solvents, and using these solvents can prevent the alignment film from being contaminated. I also found that it was not good.

  The spacer dispersion in the present invention is preferably blended so that the surface tension thereof is [surface energy of substrate −5] to 50 (mN / m). For example, when the surface energy of the substrate is 30 mN / m, 25 to 50 mN / m is preferable. When the surface tension is [surface energy of substrate -5] mN / m, the contact angle (initial contact angle) of the spacer dispersion liquid droplets discharged onto the substrate is highly hydrophobic (low surface tension). Even on a substrate using an alignment film or the like, it cannot be enlarged, and the spacer dispersion liquid is wet and spread on the substrate, so that the spacer arrangement interval cannot be reduced, or if it is larger than 50 mN / m, There may be a problem that bubbles remain in the nozzle and cannot be discharged.

  In addition, the spacer dispersion liquid is preferably adjusted so that the initial contact angle θ between the spacer dispersion liquid and the substrate surface is 10 to 110 degrees. When the initial contact angle between the spacer dispersion liquid and the substrate surface is less than 10 degrees, the spacer dispersion liquid droplets discharged onto the substrate are wet and spread on the substrate, and the spacer spacing cannot be reduced. If the angle is greater than 110 degrees, the liquid droplets easily move around on the substrate with a slight vibration, resulting in a problem that the placement accuracy is deteriorated and the adhesion between the spacer and the substrate is deteriorated.

  The viscosity at the time of discharge of the spacer dispersion liquid in the present invention is preferably too high because it cannot be discharged by the ink jet apparatus, and if it is too low, even if it can be discharged, it becomes difficult to control the discharge amount. Is 0.5 to 15 mPa · s, more preferably 5 to 10 mPa · s. When discharging the spacer dispersion liquid, the head temperature of the ink jet apparatus is cooled by a Peltier element, a refrigerant, or the like, or heated by a heater or the like, so that the liquid temperature at the time of discharging the spacer dispersion liquid is −5 ° C. You may adjust between 50 to 50 degreeC.

The solid content concentration of the spacer particles in the spacer dispersion is preferably from 0.01 to 5% by weight, more preferably from 0.1 to 2% by weight. If it is less than 0.01% by weight, the probability that the spacers are not included in the discharged droplets becomes high, which is not preferable. On the other hand, if it exceeds 5% by weight, the nozzles of the ink jet device are likely to be clogged, or the number of spacers contained in the dispersed liquid droplets that have landed will increase so that it is difficult for the spacers to move during the drying process.
In the spacer dispersion liquid, the spacer particles are preferably dispersed in the form of single particles. The presence of aggregates in the dispersion liquid is not preferable because not only the discharge accuracy is lowered, but in the case of remarkable, the nozzles of the ink jet apparatus may be clogged.

  In the present invention, within the range that does not hinder the effects of the present invention, the adhesive component for imparting adhesiveness in the spacer dispersion liquid, the dispersion of the spacer is improved, and the physical properties such as surface tension and viscosity are controlled. Various surfactants, viscosity modifiers, and the like may be added for the purpose of improving discharge accuracy or improving spacer mobility.

The inkjet apparatus according to the present invention is not particularly limited, and is a normal ejection method such as a piezo system that ejects a liquid by vibration of a piezo element or a thermal system that ejects a liquid by utilizing the expansion of the liquid due to rapid heating. Is used.
The nozzle diameter of the ink jet apparatus is preferably 7 times or more the particle diameter. If it is less than 7 times, the nozzle diameter is too small compared to the particle diameter, and if the discharge accuracy is reduced or significant, the nozzle is blocked and discharge is not preferable.

  The reason why the discharge accuracy is lowered is considered as follows. In the piezo method, ink is sucked into an ink chamber adjacent to the piezo element by the vibration of the piezo element or ink is ejected from the ink chamber through the nozzle tip. As the droplet discharge method, the meniscus (interface between ink and gas) at the tip of the nozzle is pulled in immediately before discharge, and then the liquid is pushed out and the liquid is pushed out directly from the position where the meniscus is on standby. Although there is a method, in the general ink jet apparatus, the former striking method is the mainstream, and as a feature thereof, small droplets can be ejected. In the spacer discharge according to the present invention, the diameter of the nozzle is somewhat large and the discharge of small droplets is required, so this striking method is effective. However, in the case of the pulling method, since the meniscus is drawn immediately before discharge, when the nozzle diameter is small (the nozzle diameter is less than 7 times the particle diameter) (see FIG. 2A), there is a spacer in the vicinity of the drawn meniscus. Since the meniscus is not drawn in an axisymmetric manner, it is considered that when pushing out after the drawing, the droplet does not advance straight but bends, and the discharge accuracy is lowered. When the nozzle diameter is large (nozzle diameter is more than 7 times the particle diameter) (see Fig. 2 (b)), even if there is a spacer near the drawn meniscus, it is not affected by the spacer, so the meniscus is axisymmetric It is considered that when the liquid is drawn in and pushed out after the drawing, the liquid droplet goes straight and the discharge accuracy is improved. However, if the nozzle diameter is increased unnecessarily in order to eliminate the bending of the droplets during ejection, the ejected droplets become larger and the landing diameter becomes larger. Absent.

  The amount of the spacer dispersion liquid discharged from the nozzle is preferably 10 to 80 pl. As a method for controlling the droplet amount, there are a method for optimizing the nozzle diameter and a method for optimizing an electric signal for controlling the ink jet head. The latter is particularly important when a piezo ink jet apparatus is used.

In an ink jet apparatus, a plurality of nozzles as described above are provided in an ink jet head in a fixed arrangement system (for example, 64 or 128, etc.) at equal intervals in a direction orthogonal to the moving direction of the head. These may be provided in a plurality of rows such as two rows). The interval between the nozzles is restricted by the structure of the piezoelectric element and the nozzle diameter. Therefore, when the spacer dispersion liquid is discharged onto the substrate at intervals other than the intervals at which the nozzles are arranged, it is difficult to prepare a head at each of the discharge intervals. Discharges by tilting (rotating) the head arranged in a direction perpendicular to the scanning direction of the head (in a plane parallel to the substrate while keeping parallel to the substrate), and if all the nozzles are larger than the head spacing, In this case, the ink is ejected by only a fixed nozzle, or by tilting the head.
In order to increase productivity, a plurality of such heads can be attached to the ink jet apparatus. However, if the number of attachments is increased, the control becomes complicated, so care must be taken.

  As the substrate for discharging the spacer dispersion liquid, a substrate such as glass or a resin plate which is usually used as a panel substrate of a liquid crystal display device can be used. Each of these substrates is composed of a set of two, one of which consists of a pixel area arranged according to a certain pattern and an area that defines the pixel area. For example, in a color filter substrate, pixel areas are color filters, and these pixel areas are substantially black matrixes such as a resin in which a metal such as chrome or carbon black that hardly transmits light is dispersed. Area).

In the present invention, it is preferable to discharge onto one of the surfaces.
At this time, the location where the spacer dispersion liquid droplets are ejected and landed on the substrate is adjusted so that the receding contact angle (θr) of the spacer dispersion liquid is 5 degrees or more, or the spacer dispersion liquid Is a mixture of one or more solvents, it is preferable that the receding contact angle (θr) of the solvent having the highest boiling point among the solvents is adjusted to be 5 degrees or more.
Examples of the method for setting the receding contact angle to 5 degrees or more include a method for selecting the solvent of the spacer dispersion liquid and a method for setting the surface of the substrate to a low energy surface.

As a method of setting the surface of the substrate to a low energy surface, a method of applying a resin having a low energy surface such as a fluorine film or a silicone film may be applied, but it is necessary to regulate the alignment of liquid crystal molecules on the surface of the substrate. Therefore, a method of providing a resin thin film (usually 0.1 μm or less) called an alignment film is generally performed. A polyimide resin film is usually used for these alignment films. The polyimide resin film is obtained by applying a polyamic acid soluble in a solvent and then thermally polymerizing it, or applying a soluble polyimide resin and then drying. As these polyimide resins, those having a long side chain and a main chain are more preferable for obtaining a low energy surface. Since the alignment film controls the alignment of the liquid crystal, the surface of the alignment film is rubbed after coating.
In addition, it is necessary to select a medium for the spacer dispersion liquid that does not contaminate the alignment film by permeating or dissolving in the alignment film.

  In the present invention, the substrate on which the charged ink or the spacer dispersion liquid is discharged has a portion having a low energy surface in the region corresponding to the region that defines the pixel region. The droplets of the spacer dispersion liquid are landed so as to be present at a portion having a low energy surface. Here, the region corresponding to the region that defines the pixel region is the region that defines the pixel region (the above-described black matrix for a color filter substrate) or the other substrate (the TFT array for a TFT liquid crystal panel). When the substrate is superposed on a substrate having a region that defines a pixel region, the region corresponds to the region having the pixel region (such as a wiring portion in the case of a TFT array substrate).

The surface energy of the portion having a low energy surface is preferably 45 mN / m or less, more preferably 40 mN / m or less. If it exceeds 45 mN / m, as long as a spacer dispersion having a surface tension that can be ejected by an ink jet apparatus is used, the liquid droplets will spread on the substrate and the spacer will protrude from the area defining the pixel area. become.
The low energy surface obtained by applying an alignment film or the like may be only the location where the spacer lands or the entire surface of the substrate. Considering processes such as patterning, the entire surface is usually a low energy surface.

In the present invention, the spacer dispersion liquid droplets are landed on the substrate on which the spacer dispersion liquid is discharged so that the liquid droplets after landing are present in the region corresponding to the region defining the pixel region. However, it is preferable that there is a wiring material made of a material that can be charged adjacent to the landing point, and it is even more preferable to charge the wiring material to a charge opposite to that of the charged particles. preferable.
The term “adjacent” here does not necessarily mean that the landed droplets are in direct contact with the wiring material. For example, a low-energy surface material such as an alignment film as described above is interposed on the wiring material. In addition, the case where the droplet landed through the film and the wiring material are close to each other is included (of course, it may be in direct contact).

Specifically, such a wiring material may be charged with a charge different from that of other portions only in such portions as gate electrode lines, source electrode lines, and arrays in an array substrate of a liquid crystal panel such as TFT or TFD. Possible metallic materials such as chromium, molybdenum, tantalum, and aluminum with electrical conductivity. Here, charging is performed by applying a voltage so that a potential difference is generated between the other portion and the wiring material. At this time, it is preferable that the potential be opposite to that of the charged spacer.
In many cases, the potential of such a wiring material is different from the charged spacer in the originally dispersed spacer dispersion, and the potential of the surface-treated spacer and the potential of such a wiring material are different from each other. Since it is determined by the functional groups on the surface and the ionization tendency of atoms, there is a case where it is not necessary to apply a voltage and charge it in this way.
As for the action, it is conceivable that particles are moved and adsorbed to the portion in the droplet by electrostatic interaction (so-called electrostatic electrophoresis effect). Accordingly, the metal species such as wiring, the functional group of the compound used for the surface treatment, etc. are changed (for example, using an ionic functional group), or the wiring or substrate (such as source wiring or gate wiring). By applying a positive or negative voltage that does not damage the circuit over the entire surface (until the spacer dispersion liquid lands and dries), the gathering of the spacers can be controlled.

In the present invention, the substrate on which the spacer dispersion liquid is discharged has a portion having a low energy surface in the region corresponding to the region defining the pixel region, and the droplet after landing has a low energy surface. The droplets of the spacer dispersion liquid are landed so as to be present at the portions having the same, but there may be included portions having a step and a periphery. In addition, it is more preferable that the charged ink is discharged and dried only at a portion having a step.
Here, the level difference is an unintentional unevenness (level difference from the surroundings) caused by wiring provided on the substrate, or intentionally provided to collect spacers as in the present invention. The structure below the surface of unevenness is not questioned. Therefore, the level difference referred to here refers to the level difference between the concave or convex portion and the flat portion (reference plane) in the surface uneven shape.

Specifically, for example, in an array substrate in a TFT liquid crystal panel, a step due to a gate electrode or a source electrode (about 0.2 μm, FIGS. 3A to 3C) or a step due to an array (about 1.0 μm, FIG. 3 (g)), in the color filter substrate, there is a recess step (about 1.0 μm, FIGS. 3D to 3F and 3H) between the image color filters on the black matrix.
In the present invention, when the spacer particle diameter is D (μm) and the step is B (μm), the step is preferably a step having a relationship of 0.01 μm <| B | <0.95D.
If it is smaller than 0.01 μm, it is difficult to collect spacers around the step, and if it exceeds 0.95 D, it becomes difficult to obtain a substrate gap adjusting effect by spacer particles.
Regarding the effect of the step, if there is a step, the droplet drying center is artificially fixed to the step portion at the final stage of drying, so that after the landed spacer dispersion droplet is dried, the spacer is moved to the pixel region. It is explained that the images can be collected at a very limited position around the step in the area corresponding to the area where the image is drawn.
In this case, as shown in FIG. 6, the position where the spacer finally remains after drying is often a corner if it is a convex portion and is in a recess if it is a concave portion.

  In the present invention, the spacer dispersion liquid is ejected to a specific position corresponding to a region defining the pixel region of the substrate described above by an ink jet method and dried. At this time, since the spacer is subjected to a chargeable process, as described above, the spacer gathers due to electrostatic interaction in addition to the effect of drying the medium, and the placement accuracy is improved.

  That is, when there is no part where the spacers gather due to the electrostatic interaction (see FIG. 4A), on the area (or the area corresponding to it) that defines the pixel area at a constant interval (s1 = s2). Even if the spacer dispersion liquid is ejected, if any part of the droplet edge is fixed for some reason during the drying process (see FIGS. 4A and 4), the left edge except for the central droplet is left. Are fixed during drying), even if the spacers after drying gather at one place in each place, the interval is not constant (L1 ≠ L2), and the spacer protrudes into the pixel region. On the other hand, if there is a part where spacers gather due to electrostatic interaction (see FIG. 4B), even if any part of the droplet end is fixed for some reason during the drying process. Even if (see FIGS. 4B and 2), as the drying further proceeds, the droplet end is fixed at the site where the spacers gather due to electrostatic interaction (see FIGS. 4B and 3). ), The spacer is fixed there. Since the fixing force at the part where the spacer gathers due to electrostatic interaction is strong, the fixing of the end of the liquid droplet is released, and finally it dries toward the part where the spacer gathers due to electrostatic interaction. The dried spacers gather in one place at each location, and the interval between them is almost constant (L1≈L2) and does not protrude into the pixel region.

  FIG. 5 shows a case (b) in which the wiring portion is used as a portion 14 where the spacers gather by electrostatic interaction when the spacer dispersion liquid is discharged at a constant interval (s1 = s2). It is the figure which showed typically the case where there is no site | part which a spacer gathers by interaction (a). That is, FIG. 5B schematically shows the state of the spacers gathered in the drying process after the spacer dispersion liquid is discharged when the wiring portion is used as the portion 14 where the spacers gather by electrostatic interaction. In the figure, spacers gather at the wiring portion (L1≈L2) and do not protrude into the pixel region. FIG. 5A shows a case where there is no part where the spacers gather due to electrostatic interaction, and the gathering position of the spacers shifts to the left and right (L1 ≠ L2), so that they protrude into the pixel area.

  In the present invention, it is preferable that the spacer dispersion liquid is discharged onto the substrate with an interval of formula (1) or more. This interval is the minimum interval between droplets when the next droplet is ejected while the landed spacer dispersion droplet is not dried.

上記より小さな間隔で吐出しようとすると、液滴径が大きいままなので着弾径も大きくなり液滴の合着が起き、乾燥過程で粒子の凝集方向が一カ所に向かって起こらなくなり、結果として乾燥後のスペーサの配置精度が悪くなったりする問題が発生する。また、吐出液滴量を小さくしようとしてノズル径を小さくすると、相対的にスペーサ粒子径がノズル径に対して大きくなってしまうので先述したようにインクジェットヘッドノズルより安定的（常に同一方向に直線的）にスペーサ粒子を吐出できず、飛行曲がりにより着弾位置精度が低下する。また、粒子によってノズルが閉塞する場合がある。

If you try to eject at a smaller interval than the above, the droplet diameter will remain large, so the landing diameter will also increase and droplet coalescence will occur, and the aggregation direction of the particles will not occur toward one place during the drying process, and as a result after drying There arises a problem that the arrangement accuracy of the spacers deteriorates. Further, if the nozzle diameter is reduced in order to reduce the discharge droplet amount, the spacer particle diameter becomes relatively larger than the nozzle diameter, so that it is more stable than the inkjet head nozzle as described above (always linear in the same direction). ), The spacer particles cannot be discharged, and the landing position accuracy decreases due to the flight bend. Further, the nozzle may be blocked by particles.

It is preferable that the arrangement number (dispersion density) of the spacers discharged and arranged on the substrate as described above is usually 50 to 350 pieces / mm ² . Any pattern may be arranged in any part of the region corresponding to the region defining the pixel region such as black matrix or the region defining the pixel region such as wiring as long as the particle density is satisfied. However, in order to prevent protrusion to the display unit (pixel area), for a color filter composed of a grid-shaped light-blocking area (area that defines the pixel area), the grid-shaped light-blocking area on one substrate It is more preferable to arrange with aiming at the location corresponding to the grid points.
The number of spacers at one arrangement position is different for each arrangement place, but is generally about 0 to 12, and the average number is about 2 to 6. The average number is adjusted by the particle diameter of the spacer and the concentration of the spacer dispersion.

Further, in this way, in order to discharge the spacer dispersion liquid and land the droplets on the substrate, the inkjet head can be scanned once or divided into a plurality of times. In particular, when the interval at which the spacers are to be arranged is narrow (from the formula (1)), discharge is performed at an integer multiple of the interval, dried once, shifted by that interval, and then discharged again. You can also do things. With respect to the movement (scanning) direction, it is possible to alternately change (reciprocal discharge) for each discharge, or discharge only when moving in one direction (unidirectional discharge).
Further, as such an arrangement method, as disclosed in Japanese Patent Application No. 2000-19456, the head is tilted so as to have an angle with the perpendicular to the substrate surface, and the droplet discharge direction is changed (usually parallel to the perpendicular to the substrate surface). In addition, by controlling the relative speed between the head and the substrate, it is possible to reduce the diameter of the droplets that land, and to make it easier to fit the spacers in the region that defines the pixel region or the region that corresponds to it. .

Next, a process of drying the medium (solvent, solvent) in the dispersion after the spacer dispersion has landed on the substrate will be described.
The conditions for drying in the present invention include heating the substrate or blowing hot air, and are not particularly limited. In order to gather the spacers near the center of the landing droplets during the drying process, the boiling point of the medium It is preferable to set the drying temperature, drying time, surface tension of the medium, contact angle of the medium with respect to the alignment film, the concentration of the spacer, and the like under appropriate conditions.
In order to gather the spacers in the landing droplets during the drying process, the spacers are dried with a certain time width so that the liquid does not disappear while the spacers move on the substrate. For this reason, the conditions which a medium dries rapidly are not preferable. Further, if the medium is in contact with the alignment film for a long time at a high temperature, the alignment film is contaminated and the display image quality of the liquid crystal display device may be impaired.
It is not preferable to use a medium that is extremely volatile at room temperature or under such a condition that it is volatile at a room temperature, because the spacer dispersion near the nozzles of the ink jet apparatus tends to dry and impairs the ink jetting properties. Further, aggregated particles may be generated during the production of the dispersion or by drying in a tank, which is not preferable.
Even if the substrate temperature is relatively low, if the drying time is remarkably increased, the production efficiency of the liquid crystal display device is lowered, which is not preferable.

In the present invention, the substrate surface temperature when the spacer dispersion reaches the substrate is preferably 20 ° C. or more lower than the boiling point of the lowest boiling solvent contained in the dispersion. When the temperature is higher than the boiling point of the lowest boiling point solvent by 20 ° C., the lowest boiling point solvent evaporates rapidly and the spacer cannot move. Since it moves around and the arrangement accuracy of the spacer is remarkably lowered, it is not preferable.
Further, when the medium is dried while the substrate temperature is gradually increased after the spacer dispersion has landed on the substrate, the substrate surface temperature until the drying is completed is preferably 90 ° C. or less, and more preferably It is 70 degrees C or less. If the substrate temperature until the drying is completed exceeds 90 ° C., it is not preferable because the alignment film is contaminated and the display image quality of the liquid crystal display device is impaired.
In the present invention, the term “drying completion” refers to the time when the droplets on the substrate disappear.

(Assembly of liquid crystal display device)
The substrate on which the spacers are arranged according to the manufacturing method of the present invention is thermocompression-bonded using an opposing substrate and a peripheral sealant, and a liquid crystal is filled in a gap between the formed substrates to form a liquid crystal display device.

(Function)
In the method for manufacturing a liquid crystal display device according to the present invention, spacer particles in which spacer particles are dispersed using an inkjet device in a liquid crystal display device comprising pixel regions arranged according to a certain pattern and light-shielding regions that define the pixel regions. The dispersion liquid is discharged, and the substrate in which spacer particles are arranged and the spacer particles are not arranged in the region corresponding to the light shielding region of the substrate on which the pixels are formed or the light shielding region of the substrate on which the pixels are not formed. In the manufacturing method of the liquid crystal display device in which the substrate is opposed to the light-shielding region or the region corresponding to the light-shielding region via the spacer particles, the spacer in the spacer dispersion liquid is charged. In addition, it is made of a wiring material made of a material that can be charged adjacent to a specific position corresponding to a region defining the pixel region. If the wiring material is made of a material made of a material that can be charged, and the wiring material is charged to the opposite charge to the charged spacer, the specific area corresponding to the area defining the pixel area is specified. As a result, when the substrate is a liquid crystal display device, the spacer can be accurately placed in the non-display portion with a narrow width, and the display image quality is lowered due to light leakage from the periphery of the spacer. Thus, an excellent liquid crystal display device free from the problem can be efficiently produced.

  With regard to this action, it is conceivable that particles are moved and adsorbed to the portion in the droplet by electrostatic interaction (so-called electrostatic electrophoresis effect).

  In the present invention, since the liquid crystal display device is manufactured by the manufacturing method in which the spacers are arranged by the ink jet method as described above, it is possible to efficiently manufacture a liquid crystal display device having excellent display image quality without light leakage by the spacers. become.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[Examples 1-11 and Comparative Examples 1-2]
A liquid crystal display element was prepared by the following method using the spacer dispersion and the substrate shown in Table 1.
(Preparation of spacer particles)
In a separable flask, 15 parts by weight of divinylbenzene, 5 parts by weight of isooctyl acrylate, and 1.3 parts by weight of benzoyl peroxide as a polymerization initiator were uniformly mixed, and then polyvinyl alcohol (GL-03, manufactured by Kuraray Co., Ltd.) After adding 20 parts by weight of a 3% aqueous solution and 0.5 parts by weight of sodium dodecyl sulfate and stirring well, 140 parts by weight of ion-exchanged water was added. The solution was reacted at 80 ° C. for 15 hours under a nitrogen stream while stirring. After the obtained particles were washed with hot water and acetone, classification operation was performed to obtain volatile spacer particles (S) using acetone. The average particle diameter of the obtained particles was 4.0 μm, and the CV value was 3.0%.

(Surface modification of spacer particles)
After 5 parts by weight of the spacer particles obtained above were put into 20 parts by weight of dimethyl sulfoxide (DMSO), 2 parts by weight of hydroxymethyl methacrylate and 18 parts by weight of N-ethylacrylamide, and uniformly dispersed by a sonicator, the reaction system Nitrogen gas was introduced into the mixture and stirring was continued at 30 ° C. for 2 hours. Next, 10 parts by weight of a 0.1 mol / l ceric ammonium nitrate solution prepared with a 1N aqueous nitric acid solution was added, and the reaction was continued for 5 hours. After completion of the reaction, the particles and the reaction solution were separated by filtration with a 2 μm membrane filter. The particles were sufficiently washed with ethanol and acetone and dried under reduced pressure in a vacuum dryer to obtain spacer SA.
Further, the spacer SB was converted into dimethyl sulfoxide (DMSO) from 5 parts by weight of the spacer particles obtained above, 20 parts by weight of dimethyl sulfoxide (DMSO), 2 parts by weight of hydroxymethyl methacrylate, 16 parts by weight of methacrylic acid, and 2 parts by weight of lauryl acrylate. A spacer SC was obtained in the same manner as described above using 20 parts by weight, 2 parts by weight of hydroxymethyl methacrylate, and 18 parts by weight of polyethylene glycol methacrylate (molecular weight 800).

(Preparation of spacer dispersion)
The spacer obtained above is taken in a necessary amount so as to have a predetermined particle concentration, slowly added to a solvent having the composition shown in Table 1, and dispersed by stirring well while using a sonicator. The mixture was filtered through an open stainless steel mesh to remove aggregates, and spacer dispersions S1 to S8 were obtained. The zeta potential of the obtained spacer dispersion was determined as “colloid chemistry IV.
Colloid chemistry experiment method (The Chemical Society of Japan, Tokyo Chemical Doujin (1996)) p217 ”. The results are shown in Table 1. The properties of the solvent used are shown in Table 2.

(Creation of substrate)
As a substrate for a liquid crystal test panel, a substrate (TFT array model substrate) imitating a color filter substrate and a TFT array substrate was used.
The color filter substrate is provided with a black matrix (width 25 μm, vertical interval 150 μm, horizontal interval 75 μm, thickness 0.2 μm) made of metal chromium on a glass substrate by a normal method, and color filter pixels consisting of three colors of RGB (Thickness 1.5 μm) was formed between them. Furthermore, an overcoat layer and an ITO transparent electrode are provided thereon, and a solution containing the polyimide (Sanver SE1211, manufactured by Nissan Chemical Industries, surface tension (γ): 26 mN / m) is uniformly formed thereon by spin coating. And dried at 80 ° C. and then baked and cured at 190 ° C. for 1 hour to form an alignment film.
At this time, a substrate having a smooth surface (see FIG. 7 (b) 15 (I)) and a substrate having a recess (step (depth) 1.3 μm) due to a difference in spacing between the color filters of each color pixel (FIG. 7). (B) 1
5 (II)) were prepared.
The TFT array substrate is provided with a copper wiring (width 8 μm, thickness 0.2 μm) on the glass substrate at a position opposite to the black matrix of the color filter substrate by a conventionally known method, and oriented by the method described above. A film was formed (see FIGS. 7B and 16I). At this time, substrates with steps of 0.005 (μm) and 1.0 (μm) were also produced.

(Spacer placement by inkjet method)
A step corresponding to the black matrix of this color filter is formed in an inkjet apparatus in which the above-mentioned TFT array model substrate is mounted on a stage heated to 45 ° C. by an attached heater and a piezo-type head having a diameter of 50 μm is mounted. Aiming, every other vertical line, the spacer dispersion liquid was discharged on the vertical line at intervals of 110 μm (arranged at a pitch of 110 μm × 150 μm in width) and dried. The distance between the nozzle (head surface) and the substrate at the time of ejection is 0.5 mm, a double pass method is used, and a potential of −3 V (to ground) is applied to the copper wire of the TFT array model substrate until it is dried. In contrast, all other devices that were applied with the potential were grounded). After confirming that the spacer dispersion liquid discharged onto the substrate on the stage was completely dried visually, on the hot plate heated to 150 ° C. to further remove the residual solvent and fix the spacer to the substrate. And heated and left for 15 minutes. Thus, the distribution density of the spacers thus arranged was 180 pieces / mm ² and the average number of spacers was 3.0 pieces / dot.

(Production of liquid crystal display cell for evaluation)
The TFT array model substrate on which the spacers are arranged as described above and the color filter substrate to be the counter substrate are bonded together using a peripheral sealing material, and the sealing material is heated at 150 ° C. for 1 hour to cure the sealing agent, and the cell gap. An empty cell in which the particle size of the spacer becomes the particle size of the spacer was prepared, then the liquid crystal was filled by a vacuum method, and the inlet was sealed with a sealing agent to prepare a liquid crystal display cell.

[Evaluation]
The following items were evaluated and are shown in Table 1.
(Spacer spray density)
After fixing the spacers to the substrate, the number of spacers dispersed per 1 mm ² was observed and used as the distribution density.
(Average number of spacers)
The average value of the number of spacers aggregated per arrangement in the range of 1 mm ² was defined as the average number of spacers. In addition, aggregation was not recognized by-mark.
(Spacer placement accuracy)
The arrangement state of the spacers after the droplets were dried was judged according to the following criteria.
○: Almost all the spacers were in the light shielding area.
(Triangle | delta): Some spacers existed in the position which protruded from the light shielding area | region.
-: Many particles were in a position protruding from the light shielding region.
(Spacer placement accuracy)
A parallel line is drawn at equal intervals on both sides from the center of the black matrix or the corresponding part, and the distance between the parallel lines in which 95% or more of the spacers exist between the two parallel lines is defined as the spacer existence range. did.
(Display quality)
The position of the spacer was observed and judged according to the following criteria.
◯: Almost no spacer was observed in the display area, and no light leakage due to the spacer was observed.
(Triangle | delta): Some spacer was recognized in the display area, and the light omission due to the spacer occurred.
-: A spacer was observed and light leakage due to the spacer was observed.

    As shown in Table 1, in the example, the spacers were almost accurately arranged in the non-display area, and the display image quality was excellent. On the other hand, in the comparative example, although they are gathered, the arrangement accuracy is poor and the non-display area is arranged, and the display image quality is inferior.

Schematic diagram showing the cross section of a liquid crystal display device (conventional example) Schematic diagram showing droplet discharge state from inkjet nozzle (a) When meniscus is not an axis object (b) When meniscus is an axis object Schematic diagram showing examples of steps Schematic diagram showing the drying process seen from the side (a) When there is no part where spacers gather due to electrostatic interaction (b) When there is part where spacers gather due to electrostatic interaction Schematic diagram showing the drying process seen from above (a) When there is no part where spacers gather due to electrostatic interaction (b) When there is part where spacers gather due to electrostatic interaction Schematic showing the position where the spacer remains Schematic diagram of the substrate used in the examples (a) View from above (b) View from the side Schematic diagram showing the evaluation method of the existence range of spacer particles

Explanation of symbols

1: Transparent (glass) substrate 2: Polarizing plate 3: Transparent electrode 4: Color filter 5: Black matrix 6: Overcoat 7: Liquid crystal 8: Spacer 9: Alignment film 10: Sealing agent 11: Meniscus 12: Spacer dispersion 13 : Landing spacer dispersion liquid droplet 14: Site where spacers gather due to electrostatic interaction 15, 15 (I), 15 (II): Color filter substrate 16, 16 (I): TFT array model substrate B: Stepped portion Height d: Distance between parallel lines in which 95% or more of the spacer particles exist

Claims (3)

In a liquid crystal display device comprising a pixel region arranged according to a certain pattern and a light-shielding region that defines the pixel region, a pixel particle is formed by discharging a spacer particle dispersion liquid in which spacer particles are dispersed using an inkjet device. A substrate in which spacer particles are arranged in a region corresponding to a light shielding region of a substrate on which the pixel is not formed or a region in which pixels are not formed, and a substrate in which spacer particles are not arranged in the light shielding region or the light shielding region. corresponding method of manufacturing the liquid crystal display device opposed to each other through a spacer particle arranged in the area, charged to the spacer particles of the spacer dispersion has been applied, the spacer dispersion has a surface at 20 ° C. A solvent having a boiling point of 25 mN / m or less and a boiling point of less than 100 ° C., and a boiling point having a surface tension at 20 ° C. of 30 mN / m or more. Method of manufacturing a liquid crystal display device but by an inkjet method, characterized by containing a 0.99 ° C. or more solvents. 2. The method of manufacturing a liquid crystal display device according to claim 1, wherein there is a wiring material made of a material that can be charged adjacent to a specific position corresponding to a region defining the pixel region. . 3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the wiring material made of a material that can be charged is charged to a charge opposite to that of the charged spacer.

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