JP2009109542A - Color filter and in-plane switching mode-type liquid crystal display device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the elusion of a component (resistance to liquid crystal) which is derived from a pigment in the coloring layer of the filter to liquid crystal in a color filter for an in-plane switching mode-type liquid crystal display device, while restraining reduction in specific resistance of liquid crystal, and ensuring a voltage maintenance rate which keeps display quality excellent. <P>SOLUTION: As pigments in a blue-color coloring layer, one or more pigments selected from the group consisting of PB15:1, 15:2, 15:3 and 15:4 are contained, or one or more pigments selected from the group consisting of PB15:1, 15:2, 15:3 and 15:4, and PV23 are contained. In this case, B/V is 100/0-75/25, and B/V is 88/12-80/20, wherein B represents the total weight of PB15:1, 15:2, 15:3 and 15:4, and V represents the weight of PV23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color filter for a liquid crystal display device and a liquid crystal display device, and in particular, improves the chemical resistance (liquid crystal resistance) of a blue colored layer of the color filter to reduce elution into the liquid crystal, and is transparent The present invention relates to a color filter capable of obtaining a liquid crystal display device having a sufficiently good voltage holding ratio without providing a protective layer (overcoat layer) made of resin, and a horizontal electric field type liquid crystal display device including the color filter.

  Color liquid crystal display devices are rapidly spreading mainly in computer terminal display devices and television image display devices. The color filter is an indispensable important component for color display of a liquid crystal display device. In recent years, this liquid crystal display device has a high demand for higher image quality, and various new types of liquid crystal display devices having a high viewing angle and high-speed response have appeared. Among these, the horizontal electric field method (In Plane Switching = IPS method) is a method that is widely used because it has excellent display quality such as viewing angle and contrast ratio.

  However, unlike other Twisted Nematic methods (TN method), Vertical Alignment method (VA method), and the like, a horizontal electric field type liquid crystal display device does not include a transparent electrode layer on a pixel. Since the transparent electrode layer is generally made of an inorganic material such as a composite oxide of indium and tin (ITO), the transparent electrode layer also functions as a protective film that improves the chemical resistance of the pixel. However, the color filter used in the lateral electric field method does not have a transparent electrode layer that has also served as a protective film.

  In recent applications for television image display devices, there is a strong demand for improvement in contrast. Since the contrast of the color filter is dominant in the contrast of the liquid crystal display device, the demand for improving the contrast of the color filter is very strong. The contrast of the color filter is mainly determined by the organic pigment contained in the colored layer, and the contrast is improved as the particle diameter of the pigment is reduced. However, when the particle size is made fine, the specific surface area increases, and thus the chemical resistance decreases. When used in the horizontal electric field method, there is no transparent electrode layer that also served as a protective film as described above, so the influence of this decrease in chemical resistance is significant, and a defect in the manufacturing process of the liquid crystal display device This is a cause of deterioration in reliability and display quality.

  This decrease in chemical resistance is due to the nature of the pigment contained in the colored layer and the fine particle size, and it is difficult to fundamentally avoid it in view of the required characteristics of color filters in recent years. Therefore, a color filter for a horizontal electric field type liquid crystal display device is generally provided with a chemical resistance by providing a protective layer (overcoat layer) of a transparent resin on a colored layer.

However, the price of liquid crystal display devices in recent years has been remarkably reduced, and the color filter that is a member of the liquid crystal display device has been urged to reduce the price. As described above, the horizontal electric field type liquid crystal display device is provided with an overcoat layer made of a transparent resin. However, the overcoat layer may need to be provided with a thickness of 2 μm or more in some cases, and it may be applied uniformly. It is difficult to do so, which is one factor that hinders price reduction. In addition, the material cost and the yield reduction due to the increase in the process are also factors that hinder the price reduction, and there is a demand for a color filter that can be used in a horizontal electric field type liquid crystal display device without providing an overcoat layer. Because of the above problems, it was difficult to realize.
Japanese Patent No. 3375325

The present invention has been made to solve the above-described problem, and is incorporated in a liquid crystal display device without an electrode between the pixel and the liquid crystal, with the pixel formation surface of the color filter facing the liquid crystal sandwiching surface side. Improves the chemical resistance (liquid crystal resistance) of the colored layer of the color filter for horizontal electric field type liquid crystal display devices, and it is sufficient in the manufacturing process of the liquid crystal display device without providing a protective layer (overcoat layer) with transparent resin Color filter that can ensure the proper aptitude and reliability of the liquid crystal display device, especially the specific resistance of the liquid crystal in the liquid crystal display device by improving the elution of the component derived from the pigment of the colored layer into the liquid crystal (liquid crystal resistance) It is an object of the present invention to provide a color filter that can suppress a decrease in the voltage and secure a voltage holding ratio that maintains a good display quality of a liquid crystal display device.
It is another object of the present invention to provide a horizontal electric field liquid crystal display device including the color filter and having a good voltage holding ratio.

  The present invention relates to a color filter used in a liquid crystal display device having a plurality of color pixels on a transparent substrate, and C.I. as a pigment in a blue coloring layer constituting a blue pixel in the plurality of color pixels. I. Pigment Blue 15: 1, 15: 2, 15: 3, or 15: 4 contains one or more, or C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, or 15: 4 and at least one of C.I. I. Pigment Violet 23 and C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4 total weight B, C.I. I. When the weight of the PigmentViolet 23 is V, B / V is 100/0 to 75/25.

  The present invention is the color filter according to the above invention, wherein the B / V is 88/12 to 80/20.

  In the color filter according to the present invention, the elution of the component derived from the pigment in the blue colored layer into the liquid crystal is blue colored in 1 g of liquid crystal (trade name “MLC-6601” manufactured by Merck). The color filter is characterized in that the absorbance of the supernatant obtained by mixing 5 mg of layer powder and centrifuging after 1 hour at 23 ° C. is 0.23 or less.

  The present invention also provides the color filter according to the above invention, wherein a protective layer is not provided on the blue colored layer.

  Moreover, this invention is a liquid crystal display device of a horizontal electric field system provided with the color filter of any one of Claims 1-4.

  Further, the present invention is the horizontal electric field type liquid crystal display device according to claim 5, wherein the voltage holding ratio is 99.5% or more at 23 ° C.

The present invention provides C.I. as a pigment in the blue colored layer. I. Pigment Blue 15: 1, 15: 2, 15: 3, or 15: 4 contains one or more, or C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, or 15: 4 and at least one of C.I. I. Pigment Violet 23 and C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4 total weight B, C.I. I. When the weight of Pigment Violet 23 is V, B / V is 100/0 to 75/25, or the B / V is 88/12 to 80/20. The elution of the derived components into the liquid crystal (liquid crystal resistance) is improved, the decrease in the specific resistance of the liquid crystal in the liquid crystal display device is suppressed, and a voltage holding ratio that maintains the display quality of the liquid crystal display device is ensured. It becomes a color filter that can.
Accordingly, it is not necessary to provide a protective layer on the blue colored layer, and the cost can be reduced without deteriorating the quality of the liquid crystal display device by the effect of reducing the material cost and the effect of improving the yield by reducing the process. In particular, it can be suitably used for a horizontal electric field type liquid crystal display device.

  Below, the color filter by this invention is demonstrated in detail based on the embodiment. The color filter of the present invention includes a plurality of color pixels on a transparent substrate, and the plurality of color pixels are composed of at least a colored layer. A plurality of colors include a combination of red, green, and blue (R, G, and B) or a combination of yellow, magenta, and cyan (Y, M, and C). The color filter of the present invention has a blue colored layer. The present invention can be applied to color filters (that is, RGB systems).

Among organic pigments used for the colorant of the blue color layer in RGB color filters, C.I. is widely used as a pigment that is widely used because it can realize vivid and bright colors. I. PigmentBlue 15: 6 (PB15: 6).
However, since PB15: 6 contains a component that dissolves in the liquid crystal, the component derived from the pigment elutes into the liquid crystal from the blue colored layer, thereby reducing the specific resistance of the liquid crystal. This reduction in the specific resistance of the liquid crystal lowers the voltage holding ratio of the liquid crystal display device and adversely affects the display quality. That is, the liquid crystal resistance of PB15: 6 is extremely poor.

In particular, when the pigment particle size is reduced in order to improve the contrast, the tendency becomes conspicuous. Therefore, when a color filter having a blue colored layer containing PB15: 6 is used in a horizontal electric field type liquid crystal display device. It is essential to provide a protective layer (overcoat layer) made of a transparent resin.
However, from the background detailed in the prior art, when a color filter having a blue colored layer containing PB15: 6 is used in a horizontal electric field type liquid crystal display device, it is required not to provide a protective layer made of a transparent resin. Yes.

Therefore, the present inventors have intensively studied to drastically improve the liquid crystal resistance of the blue colored layer, and as a result, have reached the present invention.
As a result of various studies on the reason why PB15: 6 is inferior in liquid crystal resistance, the present inventors have found that this is because it has an ε-type crystal structure. Therefore, further investigations were made and the blue pigment Pigment Blue 15: 1, 15: 2 (PB15: 1, PB15: 2) having the α-type crystal structure, or the blue pigment Pigment Blue 15 having the β-type crystal structure: 3, 15: 4 (PB15: 3, PB15: 4) was found to be excellent in liquid crystal resistance and to solve various problems occurring in PB15: 6. Among these blue pigments, PB15: 1 and 15: 2 having an α-type crystal structure are particularly preferable because the color development characteristics are closer to those of PB15: 6.

  In addition, in the study for improving and improving the liquid crystal resistance of the blue colored layer, the inventors have selected one or more of PB15: 1, PB15: 2, PB15: 3, and PB15: 4 and Pigment Violet 23. It has also been found that by using (PV23) in a mixture, the total amount of pigments in the blue colored layer can be greatly reduced while maintaining the same color density, and the liquid crystal resistance can be further improved.

The larger the amount of PV23 mixed, the more the total amount of pigment can be reduced while maintaining the same color density. However, when the amount of PV23 mixed is too large, the hue as blue is not satisfied. Specifically, the preferred mixing ratio is that the total weight of PB15: 1, 15: 2, 15: 3, 15: 4 is B, PV
When the weight of 23 is V, B / V = 100/0 to 75/25, more preferably about 88/12 to 80/20, since the total amount of pigment can be reduced to almost half.

  Hereinafter, a method for obtaining the color filter of the present invention will be described. The color filter of the present invention includes a plurality of color pixels on a transparent substrate, and the plurality of color pixels are composed of at least a colored layer. A plurality of colors include a combination of red, green, and blue (R, G, and B) or a combination of yellow, magenta, and cyan (Y, M, and C). The color filter of the present invention has a blue colored layer. The present invention can be particularly preferably applied to color filters (that is, RGB systems). Of course, the present invention can also be applied to a color filter in which Y, M, and C are arranged on the same substrate in addition to R, G, and B.

The color filter of the present invention is used by being incorporated in a liquid crystal display device with the pixel formation surface facing the liquid crystal sandwiching surface. An alignment film is formed on the colored layer as necessary.
In the color filter of the present invention, since the colored layer has high chemical resistance (liquid crystal resistance), it is not necessary to provide an overcoat layer covering the colored layer. Therefore, the yield is good and the cost is reduced. In addition, since the distance between the liquid crystal and the colored layer is closer, the viewing angle is improved and a high-definition liquid crystal display device can be provided.

  As described above, the color filter of the present invention does not need to be provided with an overcoat layer in order to supplement the solvent resistance of the colored layer, but supplements chemical resistance (liquid crystal resistance) such as the purpose of flattening the color filter. A layer made of a resin can be provided for other purposes. In this case, the thickness as in the conventional overcoat layer is not necessarily required.

  The transparent substrate used in the color filter of the present invention preferably has a certain degree of transmittance with respect to visible light, and more preferably has a transmittance of 80% or more. Generally, it may be one used in a liquid crystal display device, and examples thereof include a plastic substrate such as PET and glass, but a glass substrate is usually used. When using a light shielding pattern, it is sufficient to use a metal thin film such as chromium or a pattern made of a light shielding resin on the transparent substrate in advance by a known method, but particularly in the case of a horizontal electric field type liquid crystal display device. A pattern made of a light shielding resin is preferably used.

  The pixel may be formed on the transparent substrate by any known method such as an inkjet method, a printing method, a photoresist method, or an etching method. However, considering high definition, controllability and reproducibility of spectral characteristics, etc., a colored composition in which a pigment is dispersed in a transparent resin together with a photoinitiator and a polymerizable monomer in a suitable solvent is formed on a transparent substrate. A photoresist method is preferred in which a color filter is prepared by repeating the process of forming one color pixel by applying and forming a coating film, applying pattern exposure to the coating film, and developing the coating film for each color.

  When the colored layer constituting the pixel included in the color filter of the present invention is prepared by preparing a photosensitive colored composition and using a photoresist method, for example, the following method is followed. A pigment serving as a colorant is dispersed in a suitable solvent together with a photoinitiator and a polymerizable monomer in a transparent resin. There are various methods such as mill base, three rolls, jet mill and the like, and there are no particular limitations.

Specific examples of organic pigments that can be used in the colored composition forming the colored layer of the color filter of the present invention are indicated by color index numbers.
The red coloring composition for forming red pixels is mainly used for C.I. I. Pigment
In addition to Red 254, C.I. I. Pigment Red 7, 9, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 97, 122, 123, 146, 149, 168, 177, 178, 179, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 246, 255, 264, Red pigments such as 272 and 279 can be used. A yellow pigment and an orange pigment can be used in combination with the red coloring composition.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 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, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138, 139, 144, 146, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 1 73, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 213, 214 and the like.

Examples of orange pigments include C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.
Examples of the green coloring composition for forming a green pixel include C.I. I. Green pigments such as Pigment Green 7, 10, 36, and 37 can be used. The green coloring composition can be used in combination with the same yellow pigment as the red coloring composition.
As described above, the blue coloring composition for forming a blue pixel may be C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4 blue pigment, C.I. I. Pigment Violet 23 purple pigment is used.

In addition, in combination with the above organic pigments, in order to ensure good coatability, sensitivity, developability, etc. while balancing saturation and lightness, inorganic pigments should be used in combination as long as the liquid crystal resistance is not lowered. Is also possible. Examples of inorganic pigments include yellow lead, zinc yellow, red pepper, cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green, and other metal oxide powders, metal sulfide powders, and metal powders.
Furthermore, for color matching, a dye can be contained within a range that does not deteriorate liquid crystal resistance and heat resistance.

  The transparent resin used in the coloring composition 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. If necessary, the transparent resin can be used alone or as a mixture of two or more monomers or oligomers that are precursors of the transparent resin that are cured by irradiation with radiation to form a transparent resin.

  Examples of the thermoplastic resin 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. , Acrylic resins, alkyd resins, polystyrene, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene, polybutadiene, 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. In addition, linear polymers containing acid anhydrides such as styrene-maleic anhydride copolymer and α-olefin-maleic anhydride copolymer can be obtained from (meth) acrylic compounds having hydroxyl groups such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

  A polymerizable monomer or oligomer is used as the photocrosslinking agent. Polymerizable monomers and oligomers include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, β-carboxyethyl (meta ) Acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, penta Erythritol tri (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neope N-glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, ester acrylate, methylolated melamine (meth) acrylate, epoxy (meth) acrylate, Various acrylic esters and methacrylic esters such as caprolactone-modified dipentaerythritol hexaacrylate and urethane acrylate, (meth) acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide N-hydroxymethyl (meth) acrylamide, N-vinylformamide, acrylonitrile and the like. These can be used alone or in admixture of two or more.

  The amount added is preferably as long as it does not impair applicability and development suitability, and is about 20% to 80% by weight, more preferably about 50% to 70% by weight, based on the total solid content of the colored composition. is there. If the addition amount is less than this range, the crosslinkability is insufficient and the liquid crystal resistance is deteriorated. If the addition amount is more than this range, unevenness and pinholes are likely to occur when the colored composition is applied, and the applicability is remarkably deteriorated. The solubility of the liquid is remarkably lowered and the development suitability becomes poor.

  When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the coloring composition. As photopolymerization initiators, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- Acetophenone compounds such as hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl Benzoin compounds such as dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3 Benzophenone compounds such as 3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4- Thioxanthone compounds such as diethylthioxanthone, 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 (trichloromethyl) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloro) Methyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, Triazine compounds such as 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], Oxime ester compounds such as O- (acetyl) -N- (1-phenyl-2-oxo-2- (4′-methoxy-naphthyl) ethylidene) hydroxylamine, bis (2,4,6-trimethylbenzoyl) phenyl Phosphine compounds such as phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 9,10-phenanthrenequinone, camphorquinone, ethyl anthraquino Quinone compounds such as borate compounds, carbazole compounds, imidazole compounds, titanocene compounds and the like. These photopolymerization initiators can be used alone or in combination.

  The amount of the photopolymerization initiator used is preferably 0.5 to 50% by weight, more preferably 3 to 30% by weight, based on the total solid content of the colored composition.

  Further, as sensitizers, triethanolamine, methyldiethanolamine, triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, 2-Ethylhexyl 4-dimethylaminobenzoate, N, N-dimethylparatoluidine, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (ethylmethyl) Amine-based compounds such as amino) benzophenone can also be used in combination. These sensitizers can be used alone or in combination.

  The amount of the sensitizer used is preferably 0.5 to 60% by weight, more preferably 3 to 40% by weight based on the total amount of the photopolymerization initiator and the sensitizer.

  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, tris (2-hydroxyethyl) isocyanurate trimercaptopropionate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-to Azine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination.

  The amount of the polyfunctional thiol used is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight based on the total solid content of the colored composition. If it is less than 0.1% by mass, the effect of adding a polyfunctional thiol is insufficient, and if it exceeds 30% by mass, the sensitivity is too high and the resolution is lowered.

  Moreover, a thermal crosslinking agent can also be added as needed. Examples of the thermal crosslinking agent include melamine resin and epoxy resin.

  Examples of the melamine resin include alkylated melamine resins (methylated melamine resin, butylated melamine resin, etc.), mixed etherified melamine resins, and the like, which may be a high condensation type or a low condensation type. Any of these may be used alone or in admixture of two or more. Moreover, an epoxy resin can also be mixed and used as needed.

  Examples of the epoxy resin include glycerol / polyglycidyl ether, trimethylolpropane / polyglycidyl ether, resorcin / diglycidyl ether, neopentyl glycol / diglycidyl ether, 1,6-hexanediol / diglycidyl ether, ethylene glycol (polyethylene). Glycol) and diglycidyl ether. Also about these, it can use individually or in mixture of 2 or more types.

  The coloring composition can contain an organic solvent as necessary. Examples of the organic 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.

On the transparent substrate, the above-mentioned photosensitive coloring composition is applied and prebaked. As a means for applying, spin coating, dip coating, die coating, etc. are usually used. However, the coating means is not limited to these as long as it can be applied with a uniform film thickness on the substrate.
Prebaking is preferably performed at 50 to 120 ° C. for about 10 to 20 minutes. The coating film thickness is arbitrary, but considering the spectral transmittance and the like, the film thickness after pre-baking is usually about 2 to 2.5 μm. The substrate on which the photosensitive coloring composition is applied to form a colored layer is exposed through a pattern mask. A normal high-pressure mercury lamp or the like may be used as the light source.

  Subsequently, development is performed. An alkaline aqueous solution is used as the developer. Examples of the alkaline aqueous solution include a sodium carbonate aqueous solution, a sodium hydrogen carbonate aqueous solution, a mixed aqueous solution of the two, or a mixture obtained by adding an appropriate surfactant to them. After development, it is washed with water and fired to obtain a pixel of any one color. By repeating the above-described series of steps by changing the photosensitive coloring composition and pattern as many times as necessary, it is possible to obtain a colored pattern in which a necessary number of colors are combined, that is, a pixel of a plurality of colors.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited thereto without departing from the spirit of the present invention.

[Preparation of acrylic resin solution]
Preparation of the acrylic resin solution used in Examples 1 to 4 and Comparative Examples 1 and 2 will be described. The molecular weight of the resin is a weight average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography).

370 parts of cyclohexanone was placed in a reaction vessel, heated to 80 ° C. while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out a polymerization reaction.
Methacrylic acid 20.0 parts methyl methacrylate 10.0 parts n-butyl methacrylate 35.0 parts 2-hydroxyethyl methacrylate 15.0 parts 2,2'-azobisisobutyronitrile 4.0 parts 20.0 parts of paracylphenol ethylene oxide modified acrylate (“Aronix M110” manufactured by Toa Gosei Co., Ltd.).

After completion of the dropwise addition, the mixture was further reacted at 80 ° C. for 3 hours, and then 1.0 part of azobisisobutyronitrile dissolved in 50 parts of cyclohexanone was added, and the reaction was further continued at 80 ° C. for 1 hour. A resin solution was obtained. The weight average molecular weight of the acrylic resin was about 40,000.
After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20 wt%. To prepare an acrylic resin solution.

[Preparation of pigment dispersion]
Red Pigment 1 (CI PigmentRed254, Ciba Specialty Chemicals “IRGAPHORREDB-CF”; R-1) is the first pigment, and Red Pigment 2 (CI PigmentRed 177, Ciba Specialty Chemicals) “CROMOPHTALREDA2B”; R-2) was used as the second pigment, and the mixture having the composition (weight ratio) shown in Table 1 was uniformly stirred and mixed, and then dispersed in an Eiger mill for 2 hours using zirconia beads having a diameter of 0.5 mm. Thereafter, the mixture was filtered through a 5 μm filter to prepare a pigment dispersion RP-1.

  Green pigment 1 (CI Pigment Green 36, “LIONOLGREEN 6YK” manufactured by Toyo Ink Co., Ltd .; G-1) is used as the first pigment, and yellow pigment 1 (CI Pigment Yellow 150, “FANCHON FASTYELLOWY-5688” manufactured by BAYER; Y-1) was used as the second pigment, and a mixture having a composition (weight ratio) shown in Table 1 was uniformly stirred and mixed, and then dispersed with an Eiger mill for 2 hours using zirconia beads having a diameter of 0.5 mm. It filtered with the filter and produced the pigment dispersion GP-1.

  Blue Pigment 1 (CI Pigment Blue 15: 6, “LIONOLBLUEES”; B-1) manufactured by Toyo Ink Manufacturing Co., Ltd. is used as the first pigment, Purple Pigment 1 (CI Pigment Violet 23, Toyo Ink Manufacturing Co., Ltd.) “LIONOGENVIOLETRL”; V-1) was used as the second pigment, and a mixture having the composition (weight ratio) shown in Table 1 was uniformly stirred and mixed, and then dispersed in an Eiger mill for 2 hours using zirconia beads having a diameter of 0.5 mm. Thereafter, the mixture was filtered through a 5 μm filter to prepare pigment dispersion BP-1.

  Blue Pigment 2 (CI Pigment Blue 15: 1, “PV Fast Blue BV” manufactured by BASF; B-2) is the first pigment, and Purple Pigment 1 (CI Pigment Violet 23, manufactured by Toyo Ink Manufacturing Co., Ltd.) LIONOGENVIOLETRL "; V-1) as a second pigment, a mixture having the composition (weight ratio) shown in Table 1 was uniformly stirred and mixed, and then dispersed in an Eiger mill for 2 hours using zirconia beads having a diameter of 0.5 mm. It filtered with a 5 micrometers filter, and produced pigment dispersion BP-2-6.

［着色組成物の調製］
次いで、表２に示す組成（重量比）の混合物を均一になるように攪拌混合した後、１μｍのフィルタで濾過して各色の着色組成物を得た。

[Preparation of colored composition]
Subsequently, the mixture of the composition (weight ratio) shown in Table 2 was stirred and mixed so as to be uniform, and then filtered through a 1 μm filter to obtain a colored composition of each color.

Monomer: alkyl-modified dipentaerythritol pentaacrylate (“Kayarad D-310” manufactured by Nippon Kayaku Co., Ltd.)
Photopolymerization initiator: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Sensitizer: 4,4′-bis (diethylamino) benzophenone (“EAB-F” manufactured by Hodogaya Chemical Co., Ltd.)
Organic solvent: cyclohexanone.

［カラーフィルタの作製］
得られた赤色着色組成物、緑色着色組成物、及び青色着色組成物を用いて下記の要領でカラーフィルタを作成した。表３に示すように、赤色着色組成物としては、表２に示すＲＲ−１を、また、緑色着色組成物としては、表２に示すＧＲ−１を本実施例（実施例１〜４、及び比較例１、２）の全てにおいて用いた。
また、青色着色組成物としては、表２に示すＢＲ−２、３、４、５を実施例１〜４に用い、表２に示すＢＲ−１、６を比較例１、２に用いた。

[Production of color filter]
A color filter was prepared in the following manner using the obtained red coloring composition, green coloring composition, and blue coloring composition. As shown in Table 3, RR-1 shown in Table 2 is used as the red coloring composition, and GR-1 shown in Table 2 is used as the green coloring composition in this example (Examples 1 to 4, And in all of Comparative Examples 1 and 2).
Moreover, as a blue coloring composition, BR-2, 3, 4, 5 shown in Table 2 was used for Examples 1-4, and BR-1, 6 shown in Table 2 was used for Comparative Examples 1 and 2.

A red coloring composition was applied to a glass substrate on which a black matrix had been formed in advance so as to have a film thickness of 2 μm by spin coating. After drying at 70 ° C. for 20 minutes, striped pattern exposure was performed using a photomask with ultraviolet rays using an exposure machine equipped with an ultrahigh pressure mercury lamp. Spray development with an alkali developer for 90 seconds, washing with ion exchange water, and air drying. Further, post-baking was performed at 230 ° C. for 30 minutes in a clean oven to form red pixels, which are striped colored layers, on a transparent substrate. The alkaline developer has the following composition. Hereinafter, in Examples 1 to 4 and Comparative Examples 1 and 2, development is performed using this alkaline developer.
・ 1.5% by weight sodium carbonate
・ Sodium bicarbonate 0.5% by weight
・ Anionic surfactant 8.0% by weight
("Peralex NBL" manufactured by Kao Corporation)
・ 90% by weight of water
Next, the green coloring composition is similarly applied by spin coating so that the film thickness becomes 2 μm. After drying, the striped colored layer was exposed and developed at a place different from the above-mentioned red pixel by an exposure machine, thereby forming a green pixel adjacent to the above-mentioned red pixel.
Further, in the same manner as red and green, a blue pixel adjacent to the red pixel and the green pixel was formed with a film thickness of 2 μm for the blue coloring composition. Thus, a color filter having striped pixels of three colors of red, green and blue on the transparent substrate was obtained.

［カラーフィルタの色度、耐液晶性の評価］
作製したカラーフィルタの青色画素の色度、耐液晶性の評価の結果を表３に示した。色度の評価は、顕微分光光度計（ＫＳオリンパス製 ＯＳＰ―ＳＰ２００）を用いた。
耐液晶性は、青色着色層中の顔料に由来する成分の液晶への溶出の度合いとし、溶出の度合いは、顔料に由来する成分が溶出した液晶の吸光度により測定した。
作製したカラーフィルタの青色着色層を削り取り粉末とし、この粉末５ｍｇを、液晶（Ｍｅｒｃｋ社製：商品名ＭＬＣ−６６０１）１ｇ中に２３℃、１時間混合後、遠心分離した上澄み液（顔料に由来する成分が溶出した液晶（溶出液晶））を採取し行った。上澄み液（溶出液晶）の分光測定には紫外可視近赤外分光光度計（島津製作所（株）製：ＵＶ−３１５０）を用いた。

[Evaluation of chromaticity and liquid crystal resistance of color filter]
Table 3 shows the results of evaluation of chromaticity and liquid crystal resistance of blue pixels of the produced color filter. For the evaluation of chromaticity, a microspectrophotometer (OSP-SP200 manufactured by KS Olympus) was used.
The liquid crystal resistance was defined as the degree of elution of the component derived from the pigment in the blue colored layer into the liquid crystal, and the degree of elution was measured by the absorbance of the liquid crystal from which the component derived from the pigment was eluted.
The blue colored layer of the produced color filter is scraped off to obtain a powder, and 5 mg of this powder is mixed in 1 g of liquid crystal (Merck, trade name: MLC-6601) at 23 ° C. for 1 hour, and then centrifuged (from the pigment) The liquid crystal from which the components to be eluted (elution liquid crystal) was collected. An ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation: UV-3150) was used for spectroscopic measurement of the supernatant (elution liquid crystal).

As shown in Table 3, Comparative Example 1 is a color filter using conventional PB15: 6 for the coloring composition forming the blue colored layer, and the absorbance at λmax (absorption maximum wavelength) of the eluted liquid crystal is 0.
. It was as large as 830, and coloring was clearly recognized visually.
On the other hand, Examples 1 to 4 and Comparative Example 2 are color filters using PB15: 1, and the absorbance at λmax of the eluted liquid crystal is reduced to ¼ to ３, and visual coloring is also possible. Almost not recognized. When Examples 1 to 4 and Comparative Example 2 were compared, the greater the content of PV23, the smaller the absorbance of the eluted liquid crystal was observed, and B / V = 100/0 to 75/25 was favorable. In Comparative Example 2 where B / V = 70/30, the chromaticity coordinate x with the C light source was as large as 0.155, and even with visual evaluation, it was not perceived as blue but perceived as purple.

[Liquid crystal cell evaluation]
The produced color filter and the counter electrode substrate were bonded together by a known method, and liquid crystal was sealed to produce a transverse electric field type liquid crystal cell. Table 4 shows the results of measuring the voltage holding ratio between the pixel electrode and the common electrode for the horizontal electric field type liquid crystal cell.
The liquid crystal used for the production of the horizontal electric field type liquid crystal cell is a product name “MLC-2041” manufactured by Merck & Co., Ltd., and the alignment film is a product name “Sanyubar 1410” manufactured by Nissan Chemical Co., Ltd.

In the liquid crystal cells using the color filters of Examples 1 to 4, the voltage holding ratio showed a good value of 99.5% or more, but both Comparative Examples 1 and 2 were 99.5% or less. Further, the display quality after aging treatment of the liquid crystal cell at 60 ° C. for 500 hours was good in the liquid crystal cell using the color filter of Examples 1 to 4, but the color quality of Comparative Examples 1 and 2 In a liquid crystal cell using a filter, spots were generated and display quality was poor.
That is, as shown in Examples 1 to 4 in Table 3, a color filter having a blue colored layer with an elution degree of 0.230 or less in absorbance is protected on the blue colored layer as shown in Table 4. Even when it was used for a liquid crystal display device without providing a layer, a result was obtained that the voltage holding ratio of the liquid crystal display device was good, that is, the display quality was good.

Claims (6)

  In a color filter used in a liquid crystal display device having a plurality of color pixels on a transparent substrate, C.I. as a pigment in a blue coloring layer constituting a blue pixel in the plurality of color pixels. I. Pigment Blue 15: 1, 15: 2, 15: 3, or 15: 4 contains one or more, or C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, or 15: 4 and at least one of C.I. I. Pigment Violet 23 and C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4 total weight B, C.I. I. A color filter, wherein B / V is 100/0 to 75/25 when the weight of PigmentViolet 23 is V.   2. The color filter according to claim 1, wherein the B / V is 88/12 to 80/20.   The elution of the component derived from the pigment in the blue colored layer into the liquid crystal was performed by mixing 5 mg of the powder of the blue colored layer in 1 g of liquid crystal (trade name “MLC-6601” manufactured by Merck) at 23 ° C. for 1 hour. The color filter according to claim 1 or 2, wherein the absorbance of the supernatant after centrifugation is 0.23 or less.   The color filter according to claim 1, wherein a protective layer is not provided on the blue colored layer.   A horizontal electric field type liquid crystal display device comprising the color filter according to claim 1.   6. The horizontal electric field type liquid crystal display device according to claim 5, wherein the voltage holding ratio is 99.5% or more at 23 ° C.