JP2010060987A - Composition for optical compensation film and color filter substrate provided with the optical compensation film composed of the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that the film thickness of an optical compensation layer is required to be precisely controlled, the control of the phase difference is not easy and a development process causes the increase of the number of steps to lower the yield, which occur when the optical compensation layer is formed on a color filter to control phase difference. <P>SOLUTION: The composition for the optical compensation film containing at least a photopolymerization initiator and a polymerizable liquid crystal. The photopolymerization initiator contains at least 1,2-octanedione 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime) by the content of 1.0-3.0 wt.% based on the weight of the polymerizable liquid crystal and contains the polymerizable liquid crystal expressed by formula (1) (in formula(1), X=4, 6). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color filter substrate having an optical compensation film used for a liquid crystal display device, and more particularly to a composition for an optical compensation film for producing an optical compensation film.

  In recent years, liquid crystal display devices have been highly evaluated for their space-saving properties, light weight, and power-saving properties due to their thinness, and recently, they are rapidly spreading to portable devices and television applications. The liquid crystal display device can perform color display by providing a color filter substrate in the panel structure, and generally uses a color filter composed of colored pixels of RGB three colors.

For liquid crystal display devices for portable devices, a reflective type or a transflective type liquid crystal display device in which a reflective part is partially formed is often used in order to ensure visibility even under strong outdoor light in the daytime. . In such a case, it is possible to correct the shift in phase difference that occurs in the configuration by incorporating a λ / 4 phase difference film, a λ / 2 phase difference film, or the like into the liquid crystal panel configuration integrally with the absorption type circularly polarizing plate. The reflected light can be used effectively.
On the other hand, a liquid crystal display device for television use is often used in combination with a retardation film and a linear polarizing plate for the purpose of further improving visibility in all directions.

  However, since such retardation films generally have the same retardation value in the plane, when the liquid crystal display device in which the retardation film is incorporated is colored by a color filter substrate, the wavelength range of light passing through each colored region Therefore, there arises a problem of whether or not appropriate phase difference control is performed.

  For example, in a reflective or transflective liquid crystal display device for portable devices, a retardation film having a retardation amount of λ / 4 (about 138 nm) in a green wavelength region (center wavelength around 550 nm) is combined with a linear polarizing plate. When used as a circularly polarizing plate, the light in the blue wavelength region (center wavelength around 450 nm) is more than λ / 4, and the light in the red wavelength region (center wavelength around 630 nm) is insufficient relative to λ / 4. In the red and blue wavelength regions, complete circularly polarized light cannot be obtained.

In addition, when a retardation film is designed so that the phase difference is compensated for one of the three colors RGB (wavelength region) in a liquid crystal display device for television applications, compensation is not possible for the other colors (wavelength region). The situation of perfection occurs. The following factors can be cited as the cause.
(1) The liquid crystal of the cell does not necessarily have the same phase difference in the entire wavelength region,
(2) Many of the colored pigments used in color filters have optical anisotropy, and the degree depends on the type of pigment, so the phase difference varies depending on the red, green, and blue pixels. is there.

  In order to solve such a problem, a method is known in which a phase difference layer is provided for each color in the liquid crystal cell and optical compensation is performed for each color.

  As an example, there has been invented a color filter substrate that expresses phase difference amounts corresponding to display pixels of three colors by forming polymerizable liquid crystal materials having different film thicknesses or different optical characteristics (for example, , See Patent Document 1).

  In addition, the light-transmitting pattern of the color filter is formed to have a different thickness for each color, and a retardation control layer such as a polymerizable liquid crystal is formed thereon, and the total thickness of the color filter layer and the retardation control layer is constant. A color filter having a phase difference control layer that expresses a phase difference amount corresponding to display pixels of three colors by stacking by a spin coat method or the like and making the thickness of the phase difference control layer different for each color. It has been invented (see, for example, Patent Document 2).

Furthermore, the thickness of the light transmissive pattern of the color filter is formed to be different for each color and further in the transmissive part / reflective part, and a retardation control layer made of a polymerizable liquid crystal or the like is formed on the color filter layer. By laminating the layers so as to flatten the step and to have different orientation directions, the transmission part has no phase difference and the reflection part has a phase difference and a value corresponding to each color (λ / 4) has also been invented. As a method for changing the orientation direction, mask rubbing or the like can be cited (for example, see Patent Document 3).
However, these conventional methods have the following problems.

  For example, in Patent Document 1, as a means for differentiating the thickness of the retardation layer for each color, a polymerization-type liquid crystal material is applied, and radiation such as ultraviolet rays is applied to each color while changing the irradiation amount for each color. A method of developing with an organic solvent is shown. In this method, especially when an uncured component remains in the cured thin film, the final film thickness greatly depends on the development conditions. Therefore, the desired film thickness can be stably controlled only by controlling the dose during exposure. There is a problem that it is difficult to obtain. In addition, when patterning a polymerization type liquid crystal material having different birefringence using a photolithography method or a printing method, a photolithography process or a printing process is required for each polymerization type liquid crystal material. There is a problem that it is not easy.

  In Patent Document 2, the thickness of the retardation control layer depends on the thickness of the underlying color filter layer. However, since the thickness of the retardation layer is not adjusted by the amount of light irradiation and development, the retardation layer is formed. Although the difficulty in the film process is somewhat eliminated, this time it becomes necessary to strictly control the thickness of the color filter layer, which limits the design of the color filter or increases the difficulty of the manufacturing process of the color filter There are problems such as. In the first place, it is easy if the base is flat, but on a color filter layer with a step difference in thickness so as to keep the total thickness of the retardation layer and the color filter layer uniform using a spin coat method or the like. It is not so easy to apply phase difference control layers having different film thicknesses.

The problem in applying the retardation layer so as to flatten the color filter including the meaning of eliminating the step of the color filter in Patent Document 3 is the same as that in Patent Document 2. As a means for differentiating the alignment method of the retardation layer made of the polymerizable liquid crystal, a method of forming an alignment film with different alignment directions by photo-alignment treatment, in Patent Document 3, alignment with different alignment directions by mask rubbing Although a method for forming a film is disclosed, an exposure apparatus becomes large and expensive, and mask rubbing is performed, for example, in order to perform photo-alignment processing, it is necessary to perform exposure from an oblique direction with polarized light exposure or non-polarized parallel light. However, there is a problem that the yield is inevitably reduced because a process involving physical contact must be performed a plurality of times.
JP 2004-191832 A JP 2005-24919 A JP 2006-85130 A

  In the present invention, the problem that arises when the above-described optical compensation layer is formed on a color filter to eliminate the phase difference adjustment for each color required in a color liquid crystal display device, and the film thickness of the optical compensation layer is precisely measured. This is to solve the problem that the control of the phase difference is not easy, the phase difference control is not easy, and the number of steps increases and the yield decreases when the development method is used.

The invention according to claim 1 for solving the above-mentioned problem is an optical compensation film composition comprising at least a photopolymerization initiator and a polymerizable liquid crystal, wherein the photopolymerization initiator is at least
1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), the content of which is 1.0 to 3.0 wt% with respect to the weight of the polymerizable liquid crystal, This is a composition for an optical compensation film.

  The invention according to claim 2 is a composition for an optical compensation film according to claim 1, which contains a polymerizable liquid crystal represented by the following (Chemical formula 1). (Where X = 4, 6)

請求項３に記載の発明は、前記重合性液晶（化１）においてXは４又は６であることを特徴とする請求項１から２のいずれか１項に記載の光学補償膜用組成物としたものである。

According to a third aspect of the present invention, in the polymerizable liquid crystal (Chemical Formula 1), X is 4 or 6, and the composition for an optical compensation film according to any one of the first to second aspects, It is a thing.

  The invention according to claim 4 is the optical compensation film composition according to any one of claims 1 to 3, wherein the composition for optical compensation film after being applied to a substrate and dried exhibits a nematic layer. It is a composition.

  The invention according to claim 5 is the composition for optical compensation film according to any one of claims 1 to 4, wherein the polymerization inhibitor is contained in an amount of 0.01 to 0.05 wt% of the total weight. Is.

  The invention according to claim 6 is an optical compensation film obtained by curing the composition for optical compensation film according to any one of claims 1 to 5 by light / thermal polymerization at a lower part or an upper part of the color filter layer. A color characterized in that the optical compensation film has a birefringence corresponding to each colored layer constituting the color filter so as to express a phase difference corresponding to each colored layer. This is a filter substrate.

  By using the optical compensation film composition according to the present invention, the color filter layer is formed on the substrate without greatly changing the thickness, and the optical compensation layer having the same film thickness is formed on the entire surface. A color filter substrate in which the phase difference is adjusted can be obtained. Since the optical compensation layer does not go through a development process and the film thickness is not precisely controlled, the phase difference can be controlled very easily.

  FIG. 1 illustrates one form (part) of a color filter substrate obtained by the present invention. This color filter substrate is configured such that an R, G, B color filter layer 6 and a liquid crystal fixing layer 7 (retardation thin film) are laminated on a glass substrate 1. As a result of the polymerization and / or crosslinking of the liquid crystal immobilization layer 7 for each color constituting the color filter layer 6, the liquid crystal compound layers are immobilized in different degrees of orientation. For example, the region R (3) is in a state in which the liquid crystal compound layer is almost completely aligned and the birefringence is most strongly expressed, and the region G (4) is in a state in which the degree of alignment is lower than that in the region R and is birefringent. The region B (5) has a lower degree of orientation than the region G and has the lowest birefringence. In general, the degree of orientation can be estimated based on the birefringence.

  When the degree of orientation of the liquid crystal fixing layer is different, the birefringence of the region is also different, so that the amount of phase difference that appears is different.

  In the present invention, the “degree of orientation” does not necessarily mean that the “degree of orientation” is constant in the thickness direction for each in-plane region. For example, in a certain region, the vicinity of the lower surface may be in a more aligned state, and the vicinity of the upper surface may be in a more non-oriented state. In this case, the “degree of orientation” is an average of the “degree of orientation” in the thickness direction.

  In the color filter substrate of the present invention, the portion corresponding to the transmissive display portion can be made optically isotropic by fixing the liquid crystal in a non-oriented state. Since the liquid crystal fixing layer region does not substantially exhibit a retardation, it functions as a simple transparent thin film.

  Since the color filter substrate of the present invention is intended to control the phase difference to a desired value by changing the birefringence of the liquid crystal fixing layer for each RGB color, it requires a different amount of phase difference. It is not necessary to change the film thickness of the liquid crystal immobilization layer even in the region to be applied. Therefore, all of the liquid crystal fixing layers on the plurality of colored pixels have substantially the same film thickness, that is, the film thickness is the same throughout the retardation film.

  Various means for obtaining a color filter substrate provided with the retardation control film of the present invention can be considered, but an existing manufacturing method can be used as a method for forming a color filter layer. The color filter layer can also be provided above or below the liquid crystal immobilization layer provided on the substrate.

  First, a case where a color composition is formed by forming a colored composition in which a pigment is dispersed in a pigment carrier into a predetermined region for each color and curing the composition to form a color filter will be described.

As the pigment contained in the colored composition, organic or inorganic pigments can be used alone or in admixture of two or more. The pigment is preferably a pigment having a high color developability and a high heat resistance, particularly a pigment having a high heat decomposition resistance, and an organic pigment is usually used. Below, the specific example of the organic pigment which can be used for a coloring composition is shown with a color index number.
Examples of the red coloring composition include C.I. I. Pigment Red 7, 14, 41, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 81: 4, 146, 168, 177, 178, 179, 184, 185, Red pigments such as 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, and 279 can be used, and a yellow pigment can also be used in combination. Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 147, 150, 151, 152, 153, 154, 155 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 198, 213, 214 and the like.

  Examples of the green coloring composition include C.I. I. Pigment Green 7, 10, 36, 37 or the like can be used, and a yellow pigment can be used in combination. As the yellow pigment, the same pigments as those mentioned for the red coloring composition can be used.

  Examples of the blue coloring composition include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, and the like can be used, and a purple pigment can be used in combination. Examples of purple pigments include C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like.

It is also possible to use inorganic pigments as pigments. Specifically, yellow lead, zinc yellow, red bean (red iron (III) oxide), cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green, and other metals. Examples thereof include oxide powder, metal sulfide powder, and metal powder. Inorganic pigments are used in combination with organic pigments in order to ensure good coatability, sensitivity, developability and the like while maintaining a balance between saturation and lightness.
The coloring composition can contain a dye within a range that does not reduce heat resistance for color matching.

The pigment carrier contained in the colored composition is for dispersing a pigment, and is composed of a transparent resin such as a thermoplastic resin, a thermosetting resin, or a photosensitive resin, a precursor thereof, or a mixture thereof. The transparent resin is a resin having a transmittance of preferably 80% or more, more preferably 95% or more in the entire wavelength region of 400 to 700 nm in the visible light region. The transparent resin includes a thermoplastic resin, a thermosetting resin, and a photosensitive resin, and its precursor includes a monomer or an oligomer that is cured by irradiation with radiation to form a transparent resin. Alternatively, two or more kinds can be mixed and used.
The pigment carrier can be used in an amount of 30 to 700 parts by weight, preferably 60 to 450 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition. When a mixture of a transparent resin and its precursor is used as a pigment carrier, the transparent resin is 20 to 400 parts by weight, preferably 50 to 250 parts by weight, based on 100 parts by weight of the pigment in the coloring composition. Can be used. The precursor of the transparent resin can be used in an amount of 10 to 300 parts by weight, preferably 10 to 200 parts by weight, with respect to 100 parts by weight of the pigment in the coloring composition.

Examples of thermoplastic resins include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, and polyester resin. And acrylic resins, alkyd resins, polystyrene resins, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polybutadiene, polyethylene, polypropylene, polyimide resins, and the like.
Examples of the thermosetting resin include epoxy resins, benzoguanamine resins, rosin-modified maleic acid resins, rosin-modified fumaric acid resins, melamine resins, urea resins, and phenol resins.

  Examples of the photosensitive resin include (meth) acrylic compounds having a reactive substituent such as an isocyanate group, an aldehyde group, and an epoxy group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group, A resin obtained by reacting an acid and introducing a photocrosslinkable group such as a (meth) acryloyl group or a styryl group into the linear polymer is used. Further, a linear polymer containing an acid anhydride such as a styrene-maleic anhydride copolymer or an α-olefin-maleic anhydride copolymer is converted into a (meth) acrylic compound having a hydroxyl group such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

  Monomers and oligomers that are precursors of transparent resins include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, polyethylene glycol di (meth) acrylate, pentaerythritol tri (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, melamine (meth) acrylate, various acrylic esters such as epoxy (meth) acrylate and methacrylic acid Examples include esters, (meth) acrylic acid, styrene, vinyl acetate, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and acrylonitrile. These can be used alone or in admixture of two or more.

When the composition is cured by irradiation with ultraviolet rays or the like, a photopolymerization initiator or the like is added to the coloring composition.
Examples of the photopolymerization initiator include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- Hydroxycyclohexyl phenyl ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane- Acetophenone photopolymerization initiators such as 1-one, benzoin photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzyldimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4 -F Benzophenone photopolymerization initiators such as nylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone Thioxanthone photopolymerization initiators such as 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s- Triazine, 2,4-bis (trichloro Til) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, etc. A polymerization initiator, a borate photopolymerization initiator, a carbazole photopolymerization initiator, an imidazole photopolymerization initiator, or the like is used.
A photoinitiator can be used in the amount of 5-200 weight part with respect to 100 weight part of pigments in a coloring composition, Preferably it is 10-150 weight part.

The above photopolymerization initiators are used alone or in combination of two or more. As sensitizers, α-acyloxy ester, acylphosphine oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone. , Camphorquinone, ethyl anthraquinone, 4,4′-diethylisophthalophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 4,4′-diethylaminobenzophenone, etc. It can also be used together.
The sensitizer can be contained in an amount of 0.1 to 60 parts by weight with respect to 100 parts by weight of the photopolymerization initiator.

Furthermore, the coloring composition can contain a polyfunctional thiol that functions as a chain transfer agent.
The polyfunctional thiol may be a compound having two or more thiol groups. For example, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene Glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, Pentaerythritol tetrakisthiopropionate, trimercaptopropionic acid tris (2-hydroxyethyl) isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimerca DOO -s- triazine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination.
The polyfunctional thiol can be used in an amount of 0.2 to 150 parts by weight, preferably 0.2 to 100 parts by weight, with respect to 100 parts by weight of the pigment in the coloring composition.

Furthermore, in the coloring composition, the pigment is sufficiently dispersed in the pigment carrier, and applied to a flat body such as a glass substrate so that the dry film thickness is 0.2 to 5 μm to form each color display pixel. A solvent can be included for ease. Examples of the solvent include cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, diethylene glycol dimethyl ether, ethylbenzene, ethylene glycol diethyl ether, xylene, ethyl cellosolve, methyl-n amyl ketone, propylene glycol monomethyl ether, toluene, Examples include methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, petroleum solvent, and the like. These may be used alone or in combination.
The solvent can be used in an amount of 800 to 4000 parts by weight, preferably 1000 to 2500 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

The coloring composition comprises one or more pigments, if necessary, together with the above photopolymerization initiator, in a pigment carrier and an organic solvent, such as a three roll mill, a two roll mill, a sand mill, a kneader, and an attritor. It can be produced by finely dispersing using a dispersing means. Moreover, the coloring composition containing 2 or more types of pigments can also be manufactured by mixing each pigment separately finely dispersed in a pigment carrier and an organic solvent. When the pigment is dispersed in the pigment carrier and the organic solvent, a dispersion aid such as a resin-type pigment dispersant, a surfactant, or a pigment derivative can be appropriately contained. Since the dispersion aid is excellent in pigment dispersion and has a great effect of preventing re-aggregation of the pigment after dispersion, a coloring composition comprising a pigment dispersed in a pigment carrier and an organic solvent using a dispersion aid is used. If so, a color filter excellent in transparency can be obtained.
The dispersion aid can be used in an amount of 0.1 to 40 parts by weight, preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  The resin-type pigment dispersant has a pigment-affinity part that has the property of adsorbing to the pigment and a part that is compatible with the pigment carrier, and adsorbs to the pigment to stabilize the dispersion of the pigment on the pigment carrier. It works. Specific examples of resin-type pigment dispersants include polycarboxylic acid esters such as polyurethane and polyacrylate, unsaturated polyamides, polycarboxylic acids, polycarboxylic acid (partial) amine salts, polycarboxylic acid ammonium salts, and polycarboxylic acid alkylamines. Salts, polysiloxanes, long-chain polyaminoamide phosphates, hydroxyl group-containing polycarboxylic acid esters, their modified products, amides formed by the reaction of poly (lower alkyleneimines) with polyesters having free carboxyl groups, and the like Water-based dispersants such as oily dispersants such as salts, (meth) acrylic acid-styrene copolymers, (meth) acrylic acid- (meth) acrylic acid ester copolymers, styrene-maleic acid copolymers, polyvinyl alcohol, polyvinylpyrrolidone Resin, water-soluble polymer, polyester Modified polyacrylate, ethylene oxide / propylene oxide addition compound, phosphate ester-based and the like are used, they can be used alone or in admixture of two or more.

Surfactants include polyoxyethylene alkyl ether sulfate, sodium dodecylbenzenesulfonate, alkali salt of styrene-acrylic acid copolymer, sodium alkylnaphthalenesulfonate, sodium alkyldiphenyletherdisulfonate, lauryl sulfate monoethanolamine, lauryl Anionic surfactants such as triethanolamine sulfate, ammonium lauryl sulfate, monoethanolamine stearate, sodium stearate, sodium lauryl sulfate, monoethanolamine of styrene-acrylic acid copolymer, polyoxyethylene alkyl ether phosphate; Polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene Nonionic surfactants such as alkyl ether phosphates, polyoxyethylene sorbitan monostearate, and polyethylene glycol monolaurate; chaotic surfactants such as alkyl quaternary ammonium salts and their ethylene oxide adducts; alkyldimethylamino Examples include amphoteric surfactants such as alkylbetaines such as betaine acetate and alkylimidazolines, and these can be used alone or in admixture of two or more.

  The dye derivative is a compound in which a substituent is introduced into an organic dye, and is preferably close to the hue of the pigment to be used. However, if the addition amount is small, those having different hues may be used. Organic dyes also include light yellow aromatic polycyclic compounds such as naphthalene and anthraquinone that are not generally called dyes. Examples of the dye derivatives are described in JP-A-63-305173, JP-B-57-15620, JP-B-59-40172, JP-B-63-17102, JP-B-5-9469, and the like. You can use what you have. In particular, a pigment derivative having a basic group is preferably used because it has a large pigment dispersion effect. These can be used alone or in admixture of two or more.

The coloring composition can contain a storage stabilizer in order to stabilize the viscosity with time of the composition. Examples of storage stabilizers include quaternary ammonium chlorides such as benzyltrimethyl chloride and diethylhydroxyamine, organic acids such as lactic acid and oxalic acid, and organic acids such as methyl ether, t-butylpyrocatechol, tetraethylphosphine, and tetraphenylphosphine. Examples thereof include phosphine and phosphite.
The storage stabilizer can be contained in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

In addition, the coloring composition may contain an adhesion improving agent such as a silane coupling agent in order to improve the adhesion to the substrate.
Examples of the silane coupling agent include vinyl silanes such as vinyltris (β-methoxyethoxy) silane, vinylethoxysilane, and vinyltrimethoxysilane, (meth) acrylsilanes such as γ-methacryloxypropyltrimethoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) methyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ) Epoxysilanes such as methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β ( Aminoethyl) γ-aminopro Lutriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N Examples include aminosilanes such as -phenyl-γ-aminopropyltriethoxysilane, thiosilanes such as γ-mercaptopropyltrimethoxysilane, and γ-mercaptopropyltriethoxysilane.
The silane coupling agent can be contained in an amount of 0.01 to 100 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

The coloring composition can be prepared in the form of gravure offset printing ink, waterless offset printing ink, silk screen printing ink, ink jet printing ink, solvent development type or alkali development type colored resist. The colored resist is obtained by dispersing a dye in a composition containing a thermoplastic resin, a thermosetting resin or a photosensitive resin, a monomer, a photopolymerization initiator, and an organic solvent.
The pigment is preferably contained in a proportion of 5 to 70 wt% based on the total solid content of the coloring composition (100 wt%). More preferably, it is contained in a proportion of 20 to 50 wt%, and the remainder consists essentially of a resinous binder provided by the pigment carrier.
The colored composition is removed by means of centrifugal separation, sintering filter, membrane filter, etc. to remove coarse particles of 5 μm or more, preferably coarse particles of 1 μm or more, more preferably 0.5 μm or more and coarse particles It is preferable to carry out.

The color filter of the present invention includes RGB colored display pixels formed on a transparent substrate by a printing method or a photolithography method (hereinafter also referred to as display pixels).
As the transparent substrate, glass plates such as soda lime glass, low alkali borosilicate glass and non-alkali alumino borosilicate glass, and resin plates such as polycarbonate, polymethyl methacrylate, and polyethylene terephthalate are used. In addition, a transparent electrode made of indium oxide, tin oxide, or the like may be formed on the surface of the planar body for driving the liquid crystal after forming the liquid crystal panel. Furthermore, the liquid crystal immobilization layer according to the present invention may be formed on the transparent substrate.

  The formation of display pixels for each color by the printing method allows patterning by simply repeating the printing and drying of the colored composition prepared as the above-mentioned various printing inks. Are better. Furthermore, it is possible to print a fine pattern having high dimensional accuracy and smoothness by the development of printing technology. In order to perform printing, it is preferable that the ink does not dry and solidify on the printing plate or on the blanket. Control of ink fluidity on a printing press is also important, and ink viscosity can be adjusted with a dispersant or extender pigment.

When forming display pixels of each color by photolithography, the colored composition prepared as the solvent development type or alkali development type color resist is applied to a transparent substrate such as spray coat, spin coat, slit coat, roll coat, etc. By a coating method, coating is performed so that the dry film thickness is 0.2 to 10 μm. When drying the coating film, a vacuum dryer, a convection oven, an IR oven, a hot plate, or the like may be used.
If necessary, the dried film is exposed to ultraviolet light through a mask having a predetermined pattern provided in contact with or non-contact with the film. Then, after immersing in a solvent or alkali developer or spraying the developer by spraying or the like to remove the uncured portion to form a desired pattern, the same operation is repeated for other colors to produce a color filter. be able to. Furthermore, in order to accelerate the polymerization of the colored resist, heating can be performed as necessary. According to the photolithography method, a color filter with higher accuracy than the above printing method can be manufactured.

In development, an aqueous solution such as sodium carbonate or sodium hydroxide is used as an alkali developer, and an organic alkali such as dimethylbenzylamine or triethanolamine can also be used. Moreover, an antifoamer and surfactant can also be added to a developing solution. As a development processing method, a shower development method, a spray development method, a dip (immersion) development method, a paddle (liquid accumulation) development method, or the like can be applied.
In order to increase the UV exposure sensitivity, after coating and drying the colored resist, a water-soluble or alkaline water-soluble resin such as polyvinyl alcohol or a water-soluble acrylic resin is applied and dried to form a film that prevents polymerization inhibition by oxygen. Thereafter, ultraviolet exposure can also be performed.

The color filter layer in the color filter of the present invention can be produced by an ink jet method, an electrodeposition method, a transfer method or the like in addition to the above method. The ink jet method is a method in which display pixels are formed by discharging and landing each color ink with a fine nozzle in a region partitioned by a light-shielding separation wall formed on a transparent substrate. The electrodeposition method is a method in which each color display pixel is electrodeposited on a transparent conductive film by electrophoresis of colloidal particles using a transparent conductive film formed on a transparent substrate. The transfer method is a method in which a color filter layer is formed in advance on the surface of a peelable transfer base sheet, and this color filter layer is transferred onto a desired transparent substrate.

  Next, a method for obtaining the liquid crystal immobilization layer of the present invention will be described. Various means can be considered as in the case of forming the color filter layer, but a polymerizable liquid crystal having a thermotropic property on the substrate (Chemical Formula 1).

を含有し（X=４〜10）、かつ光重合開始剤として、
1,2- octanedione 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime)を含む溶液を塗布し、露光と加熱を併用して硬化させる。
この時、重合性液晶は硬化後の耐熱性の観点からX＝４〜６が好ましく、さらに混和性が損なわなければX＝４〜６の重合成液晶を混合した混合物であってもかまわない。
さらに1,2- octanedione 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime)の添加量は重合性液晶の全量に対して1.0〜3.0ｗｔ％が好ましい。1.0ｗｔ％以下であると必要な最大位相差が得られず、3.0wt%以上であると必要な最小位相差が得られない。
また重合禁止剤を0.01~0.05wt%添加することは位相差の制御性が向上するのでさらに好ましい。重合禁止剤は添加してもしなくてもよい。ただし、0.05wt%以上加えることは光学補償物の耐熱性が劣化するので好ましくない。

(X = 4 to 10) and as a photopolymerization initiator,
A solution containing 1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) is applied and cured by using both exposure and heating.
In this case, the polymerizable liquid crystal is preferably X = 4 to 6 from the viewpoint of heat resistance after curing, and may be a mixture obtained by mixing polysynthetic liquid crystals of X = 4 to 6 as long as the miscibility is not impaired.
Further, the addition amount of 1,2-octaneione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) is preferably 1.0 to 3.0 wt% with respect to the total amount of the polymerizable liquid crystal. If it is 1.0 wt% or less, the necessary maximum phase difference cannot be obtained, and if it is 3.0 wt% or more, the necessary minimum phase difference cannot be obtained.
Further, it is more preferable to add 0.01 to 0.05 wt% of a polymerization inhibitor because the controllability of the phase difference is improved. A polymerization inhibitor may or may not be added. However, adding 0.05 wt% or more is not preferable because the heat resistance of the optical compensator deteriorates.

  In addition to the above liquid crystal compound and solvent, the solution is chiral agent, photopolymerization initiator, thermal polymerization initiator, sensitizer, chain transfer agent, polyfunctional monomer or oligomer, resin, surfactant, storage stabilizer, adhesion improvement Agents and other necessary materials can be added as long as the liquid crystal compound does not lose liquid crystallinity.

  Next, this solution is applied on the transparent substrate 1 or the color filter 6. At this time, if necessary, a film 2 having orientation ability such as a rubbed polyimide film is formed on the surface of the coated portion. For solution coating, spin coating method, slit coating method, letterpress printing method, screen printing, planographic printing, reversal printing, gravure printing and other printing methods or methods combining these printing methods with an offset method, ink jet method, bar A coating method and other known film forming methods can be applied.

  The type of transparent substrate is not particularly limited, but when the color filter substrate of the present invention is incorporated in a matrix type liquid crystal display device, the transparent substrate is a glass plate or a resin plate, or display pixels are formed on them. A light-transmitting substrate such as a color filter is suitable. In addition, a light-transmitting film such as a plastic film can be used as the transparent substrate.

  Subsequently, after the applied solution is dried to form a liquid crystal compound layer, pattern exposure is performed with a different dose for each color region. As a result, the color region irradiated with a sufficient amount of light to polymerize and / or crosslink the polymerizable liquid crystal is fixed while maintaining its alignment state, and a smaller amount of light is irradiated. A part of the region left uncured component is fixed and the region not irradiated with light remains unreacted. In general, ultraviolet light can be used for the exposure.

Thus, the board | substrate which exposed the irradiation amount which changes with color areas is heated more than the isotropic phase transition temperature of the said liquid crystal compound. Then, in the liquid crystal compound layer, the color area that is not irradiated with light transitions to an isotropic phase and becomes substantially non-oriented, and the color area that is irradiated with an insufficient amount of light depends on the irradiation amount. The orientation of the components that remain uncured is disturbed, resulting in a low orientation state. A color region irradiated with a sufficient amount of light remains in a fixed state with orientation maintained, that is, in a highly oriented state.

  Finally, the liquid crystal compound is heated to a temperature that is equal to or higher than the isotropic phase transition temperature of the liquid crystal compound and higher than polymerization and / or crosslinking. In this case, the region not irradiated with light first transitions to an isotropic phase and becomes substantially non-oriented, and the region irradiated with an insufficient amount of light remains an uncured component depending on the amount of irradiation. The color region irradiated with a sufficient amount of light in a low alignment state due to the disorder of the orientation of the film becomes a highly aligned state while maintaining the alignment state without being disturbed by heating, and subsequently Polymerization and / or cross-linking by heat proceeds while maintaining each state.

  As a means of irradiating different amounts of light to change the "degree of orientation" for each region, a method of performing multiple exposures using a plurality of photomasks, or moving this using the same photomask A method of performing multiple exposures, a method of using a halftone mask having a plurality of regions having different light transmittances, and a gray tone mask having a plurality of regions composed of portions having slits less than the resolution of the exposure machine. A method of using, a method of using a wavelength limiting mask having a plurality of regions having different light transmission wavelengths, and a method of scanning and drawing a light beam such as an electron beam are conceivable.

[Example 1]
The red colored composition was applied onto the substrate with a spin coater so that the dry film thickness was 1.0 μm, and then dried by heating in a clean oven at 70 ° C. for 20 minutes to obtain a coated substrate. After cooling the substrate to room temperature, ultraviolet rays were exposed through a photomask using an ultrahigh pressure mercury lamp. Thereafter, the substrate was spray-developed using a sodium carbonate aqueous solution at 23 ° C., washed with ion-exchanged water, and air-dried. Further, baking was performed at 230 ° C. for 30 minutes in a clean oven to form red pixels on the substrate. Next, a green pixel was similarly formed using the green coloring composition, and a blue pixel was further formed using the blue coloring composition, thereby obtaining a color filter layer. In either case, the film thickness was 1.0 μm.
When the in-plane retardation Re of the substrate on which the color filter layer was formed was measured, no retardation was detected in any color pixel.

  An alignment film material (“SE-1410” manufactured by Nissan Chemical Industries, Ltd.) is applied on the color filter layer of the substrate with a spin coater so as to have a dry film thickness of 0.1 μm, and on a hot plate at 90 ° C. And baked at 230 ° C. for 40 minutes in a clean oven. Subsequently, the substrate was subjected to a rubbing process in a certain direction to obtain a color filter having orientation ability.

A liquid crystal compound obtained by stirring and mixing a mixture having the following composition and filtering through a 0.6 μm filter is 1.6 μm in dry film thickness on a spin coater on the alignment film of the substrate. And then dried by heating at 90 ° C. for 2 minutes on a hot plate to obtain a liquid crystal alignment substrate. The phase transition temperature of the liquid crystal material is as shown in Table 1. Also in the optical compensation composition, the phase transition temperature after coating and drying is substantially the same.
○ Optical compensation composition 1
・ Bis (4- (6- (acryloyloxy) hexyloxy) phenyl) 2-methylterephthalate 19.5 parts ・ 1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) 0.5 parts・ Surfactant 3.0 parts ("BYK330" 2% cyclohexanone solution manufactured by Big Chemie)
・ Polymerization inhibitor (p-Methoxyphenol) 0.01 part ・ Cyclohexanone 77 part ○ Optical compensation composition 2
・ Bis (4- (6- (acryloyloxy) butanoxy) phenyl) 2-methylterephthalate 19.5 parts ・ 1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) 0.5 parts・ Surfactant 3.0 parts ("BYK330" 2% cyclohexanone solution manufactured by Big Chemie)
・ Polymerization inhibitor (p-Methoxyphenol) 0.01 part ・ Cyclohexanone 77 part ○ Optical compensation composition 3 (comparative example)
Bis (4- (6- (acryloyloxy) hexyloxy) phenyl) 2-methylterephthalate 19.5 partsIrg. 907 0.5 parts Surfactant 3.0 parts (BYK330 2% cyclohexanone solution manufactured by BYK Chemie)
・ Polymerization inhibitor (p-Methoxyphenol) 0.01 parts ・ Cyclohexanone 77 parts

Next, the liquid crystal alignment substrate was subjected to ultraviolet exposure for each color region through a photomask using an ultrahigh pressure mercury lamp. The dose of ultraviolet rays, 200 mJ / cm ² in the red pixel region, a green pixel in a region 100 mJ / cm ^2, the blue pixel area was 20 mJ / cm ^2. The results of changing the initiator amount and the polymerization inhibitor amount are shown in Tables 2 and 3. Since the optical compensation composition 2 shows almost the same result as the optical compensation composition 1, it will be omitted.

Subsequently, the substrate was placed in a clean oven and baked at 230 ° C. for 40 minutes to obtain a color filter substrate with a retardation film.
When the in-plane phase difference Re of the color filter substrate using the optical compensators 1 and 2 was measured, the red pixel portion was 158 nm for light with a wavelength of 630 nm, the green pixel portion was 138 nm for light with a wavelength of 550 nm, and the blue pixel portion was It was 113 nm in light having a wavelength of 450 nm.
On the other hand, when the optical compensator 3 was used, the red pixel portion was 160 nm for light having a wavelength of 630 nm, the green pixel portion was 160 nm for light having a wavelength of 550 nm, and the blue pixel portion was 150 nm for light having a wavelength of 450 nm. By selecting 1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), it became easy to vary the phase difference value depending on the exposure dose. FIG. 2 shows the retardation produced by the optical compensation compositions 1 to 3 as a function of the exposure amount. It is clear that compositions 1 and 2 (broken line) tend to change the phase difference more easily than composition 3 (solid line).
[Example 2]
An alignment film material (“SE-1410” manufactured by Nissan Chemical Industries, Ltd.) is applied onto the color filter layer of the substrate with a spin coater so that the dry film thickness is 0.1 μm, and is heated on a hot plate at 90 ° C. And baked at 230 ° C. for 40 minutes in a clean oven. Subsequently, a rubbing process was performed on the substrate in a certain direction to obtain a substrate having orientation ability.

A liquid crystal compound obtained by stirring and mixing a mixture having the following composition and filtering through a 0.6 μm filter is formed on the alignment film of the substrate to a dry film thickness of 1.8 μm using a spin coater. And then dried by heating at 90 ° C. for 2 minutes on a hot plate to obtain a liquid crystal alignment substrate.
・ Bis (4- (6- (acryloyloxy) hexyloxy) phenyl) 2-methylterephthalate 19.5 parts ・ 1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) 0.5 parts・ Surfactant 3.0 parts ("BYK330" 2% cyclohexanone solution manufactured by Big Chemie)
・ Polymerization inhibitor 0.01 part ・ Cyclohexanone 77.0 parts

Next, the liquid crystal alignment substrate was subjected to ultraviolet exposure for each color region through a photomask using an ultrahigh pressure mercury lamp. The dose of ultraviolet rays, 200 mJ / cm ² in the red pixel region, a green pixel in a region 100 mJ / cm ^2, the blue pixel area was 20 mJ / cm ^2.

Subsequently, the substrate was placed in a clean oven and baked at 230 ° C. for 40 minutes to obtain a substrate with a retardation film.
When the in-plane retardation Re of the retardation film substrate was measured, the red pixel portion was 170 nm for light with a wavelength of 630 nm, the green pixel portion was 150 nm for light with a wavelength of 550 nm, and the blue pixel portion was 125 nm for light with a wavelength of 450 nm. It was.

The red colored composition was applied to the substrate obtained above with a spin coater so that the dry film thickness was 1.0 μm, and then dried by heating at 70 ° C. for 20 minutes in a clean oven to obtain a coated substrate. After cooling the substrate to room temperature, ultraviolet rays were exposed through a photomask using an ultrahigh pressure mercury lamp. Thereafter, the substrate was spray-developed using a sodium carbonate aqueous solution at 23 ° C., washed with ion-exchanged water, and air-dried. Further, baking was performed at 230 ° C. for 30 minutes in a clean oven to form red pixels on the substrate. Next, a green pixel was similarly formed using the green coloring composition, and further a blue pixel was formed using the blue coloring composition to obtain a color filter layer with a retardation film.
When the in-plane retardation Re of the color filter substrate was measured, the red pixel portion was 158 nm in the light of wavelength 630 nm, the green pixel portion was 138 nm in the light of wavelength 550 nm, and the blue pixel portion was 113 nm in the light of wavelength 450 nm. .

The perspective view explaining the structure of a color filter board | substrate provided with the optical compensation film | membrane which becomes this invention. It is the figure which showed the phase difference of the optical compensation composition which becomes this invention as a function of exposure amount.

Explanation of symbols

1 ... Glass substrate 2 ... Alignment film 3 ... Red region 4 ... Green region 5 ... Blue region 6 ... Color filter layer 7 ... Phase difference control layer

Claims (6)

An optical compensation film composition comprising at least a photopolymerization initiator and a polymerizable liquid crystal, wherein the photopolymerization initiator is at least
1,2-octedione 1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), the content of which is 1.0 to 3.0 wt% with respect to the weight of the polymerizable liquid crystal, A composition for an optical compensation film. The composition for optical compensation films according to claim 1, comprising a polymerizable liquid crystal represented by the following (Chemical Formula 1). (Where X = 4, 6)

  3. The composition for an optical compensation film according to claim 1, wherein X is 4 or 6 in the polymerizable liquid crystal (Chemical Formula 1).   The composition for optical compensation films according to any one of claims 1 to 3, wherein the composition for optical compensation films after being applied to a substrate and dried exhibits a nematic layer.   The composition for an optical compensation film according to any one of claims 1 to 4, wherein the polymerization inhibitor is contained in an amount of 0.01 to 0.05 wt% of the total weight.   An optical compensation film obtained by curing the composition for optical compensation film according to any one of claims 1 to 5 by light / thermal polymerization is provided below or above the color filter layer, and the optical compensation film Is a color filter substrate characterized by having a birefringence corresponding to each colored layer constituting the color filter so as to express a phase difference corresponding to each colored layer.

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