JP2008299080A - Color filter and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter for securing adaptability and reliability to/in a lateral electric field type liquid crystal display manufacturing process, without providing a transparent resin protection layer on a colored layer, and reducing an elution of copper ion. <P>SOLUTION: In this color filter provided with a plurality of colors of pixels including a blue pixel on a transparent substrate, an amount of the copper ion eluted to N-methyl-2-pyrrolidinone from the colored layer is 4.2 ng/cm<SP>2</SP>or less in the colored layer constituting the blue pixel. An amount of a blue colored pigment is within a range of 79 to 85 wt.%, when adding C. I. Pigment 23 as a violet colored pigment to a blue colored composition using C. I. Pigment 15:6, and when total amount of the blue colored pigment and the violet colored pigment contained in the blue colored composition are 100 wt.%, in an organic pigment of the colored layer constituting the blue pixel. <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. In particular, the present invention relates to a liquid crystal display device in which a pixel formation surface faces the liquid crystal sandwiching surface and no electrode is interposed between the pixel and the liquid crystal. In a built-in liquid crystal display device, due to the reduction of copper ions eluted from the colored layer that constitutes the blue pixel, the suitability and reliability of the liquid crystal display device manufacturing process are sufficient without providing a protective layer (overcoat layer) made of transparent resin. The present invention relates to a color filter that can secure the property and a liquid crystal display device including the same.

  Color liquid crystal display devices are rapidly spreading mainly in television image display devices and computer terminal 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, high-speed response, etc. 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 systems (TN systems), Vertical Alignment systems (VA systems), etc., a horizontal electric field type liquid crystal display device does not have a transparent electrode layer on a pixel. Since the transparent electrode layer is generally made of an inorganic material such as a complex oxide (ITO) of indium and tin, it also has a function as a protective film that improves the chemical resistance of the pixel. However, in the color filter used for the lateral electric field method, there is no transparent electrode layer that has also served as a protective film.

  In color filters, in order to avoid contamination of the liquid crystal from the colored layer that may elute ionic impurities from organic pigments, organic resins with higher purity (transparent than transparent oxides and other inorganic oxide films) It is more effective to laminate a protective layer such as a (resin) layer. In general, the inorganic oxide constituting the transparent electrode is not perfect as a protective layer against ionic impurities because it has a thin film thickness of 0.1 μm or the like and has defects due to crystal grain boundaries. .

  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, if the particle size is made fine, the specific surface area increases, so the chemical resistance decreases (it is easy to activate due to the increase in surface area), and the ions eluted from the pigment component increase accordingly. 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 defects in the liquid crystal display device manufacturing process, This was a cause of deterioration in reliability.

  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, it is common to maintain a chemical resistance by providing a protective layer (overcoat layer) with a transparent resin on a colored layer in a color filter for a horizontal electric field type liquid crystal display device, It is a sure method.

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, an overcoat layer, which is a protective layer made of a transparent resin, is used in a horizontal electric field type liquid crystal display device. However, in some cases, the overcoat layer needs to have a thickness of 2 μm or more. This is one factor that hinders price reduction. In addition, the material cost and the decrease in yield due to an increase in the process are also factors that hinder the price reduction, and a color filter that can be used in a liquid crystal display device without providing an overcoat layer has been desired. This is difficult to achieve because the effect of the decrease is significant. When a color filter having no protective layer such as an overcoat layer is employed, particularly in a horizontal electric field type liquid crystal display device, an ionic impurity is liable to be adversely affected by the liquid crystal.

Patent Document 1 describes the influence of the extraction amount of the pigment itself on hydrochloric acid. However, there is no process using hydrochloric acid including the manufacturing process of the color filter and the panel forming process of the liquid crystal display device, and it is not suitable as a means for evaluating a member such as a color filter for a liquid crystal display device. Color filters and liquid crystals (color filters and liquid crystals) are not evaluated as a structure close to a liquid crystal display device as a color filter or colored layer (coating film in which an organic pigment is dispersed in a resin matrix such as an acrylic resin and formed on a glass substrate). There is a problem that is not easily associated with the reliability of the display device and the image quality evaluation.
JP 2001-166124 A

  The present invention has been made to solve the above problems, and in particular, the pixel formation surface of the color filter is on the liquid crystal sandwiching surface side, and the liquid crystal display device has no electrode between the pixel and the liquid crystal. In a built-in horizontal electric field type liquid crystal display device, the pigment of the blue colored layer is sufficient so that the liquid crystal display device can be adequately manufactured without being provided with a protective layer (overcoat layer) made of a transparent resin, and the reliability can be ensured. It aims at providing the color filter which can reduce elution of the copper ion etc. which are a component.

The invention according to claim 1 of the present invention is a color filter comprising a plurality of color pixels including a blue pixel on a transparent substrate, and a protective layer made of a transparent resin is not provided. The amount of copper ions eluted from N-methyl-2-pyrrolidinone is 4.2 ng / cm ² or less.

  In the invention described in claim 1, the organic pigment of the colored layer constituting the blue pixel is C.I. I. Pigment Blue 15: 6 is added to a blue coloring composition as a purple coloring pigment. I. Pigment Violet 23 is added, and when the total amount of the blue color pigment and the purple color pigment contained in the blue color composition is 100% by weight, the amount of the blue color pigment is 79% by weight to 85% by weight. % Is a color filter having a range of not more than%.

  Furthermore, the present invention is a liquid crystal display device in which the liquid crystal is sandwiched between two substrates and the color filter is in direct contact with the liquid crystal, and the color filter according to claim 1 or 2 is provided. This is a liquid crystal display device.

  The colored layer used in the present invention is a cured coating film on a transparent substrate of a colored composition containing an organic pigment having a predetermined thickness as a color filter. The color filter pixel (colored pixel) refers to a colored layer on a transparent substrate that is patterned into a size necessary for a liquid crystal display device.

  The present invention relates to a color filter having a plurality of color pixels on a transparent substrate, and a light mainly comprising at least an organic pigment, an acrylic transparent resin, a photocrosslinking agent, and a solvent in a colored layer constituting one color pixel. An organic pigment used for forming a colored layer constituting a blue pixel using a curable coloring composition and C.I. I. Pigment Blue 15: 6 (hereinafter abbreviated as PB15: 6) is added to a blue coloring composition as a purple coloring pigment. I. By adding Pigment Violet 23 (hereinafter abbreviated as PV23), the content of the blue coloring pigment in the blue coloring composition can be reduced, and accordingly, the elution of copper ions as a component derived from the blue coloring pigment is reduced. A color filter that can be obtained. For this reason, when used in a liquid crystal display device in which a color filter is in contact with the liquid crystal, such as a horizontal electric field method, a problem occurs in the liquid crystal display device manufacturing process without providing a protective layer (overcoat layer) made of transparent resin. It is effective as a color filter that does not deteriorate, has high reliability, or does not deteriorate image quality such as defective bright spots.

  Below, the color filter by this invention is demonstrated in detail based on the one Embodiment.

  The color filter of the present invention includes pixels of a plurality of colors on at least a transparent substrate, and the pixels of the plurality of colors are each formed by patterning with a colored layer. Examples of the plurality of colors include combinations of red, green, and blue (R, G, and B), and combinations of yellow, magenta, and cyan (Y, M, and C). The color filter of the present invention is applicable to the configuration of a color filter having a blue colored layer.

  In the liquid crystal display device manufacturing step, there is a step of forming an alignment film for regulating the alignment of the liquid crystal on the color filter. The alignment film material is generally formed by applying, drying, and baking a solution in which polyimide or a precursor thereof is dissolved in an appropriate solvent.

  As a solvent for dissolving polyimide or a precursor thereof, N-methyl-2-pyrrolidinone (hereinafter abbreviated as NMP), γ-butyrolactone, or a mixture thereof is often used as a main component. Therefore, the color filter is required not to elute ions or the like with respect to these solvents.

  Among the organic pigments used for the colorant of the blue color layer in the RGB color filter, PB15: 6 is mentioned as a pigment that can realize a bright and bright color. However, the blue colored layer using PB15: 6 has low NMP resistance, and particularly when the pigment particle size is reduced in order to improve contrast, the chemical resistance is significantly reduced, so PB15: 6 is contained. When a color filter having a blue colored layer 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 made various studies to reduce copper ions derived from PB15: 6 eluted from a color filter having a blue colored layer containing PB15: 6, and as a result, the present invention has been made.

The reason why the blue colored layer using PB15: 6 has low NMP resistance is that PB15: 6 itself has a property of being dissolved in NMP in a small amount and is eluted from the colored layer into the solvent. Therefore, in order to reduce the elution amount of PB15: 6 in the blue colored layer using PB15: 6, it is necessary to reduce the content itself of PB15: 6 contained in the blue colored composition. The present inventors have empirically confirmed that the elution amount of ionic impurities such as copper with respect to NMP can be substantially substituted as the elution amount of ionic impurities with respect to various liquid crystal materials.

  Therefore, when the total amount of PB15: 6 and PV23 contained in the blue coloring composition is 100% by weight, PV23 is added and used in proportions of 5, 10, 15, 20, 25, and 30% by weight to form a film. When the thickness is 2 μm and the y-axis value of the CIE chromaticity coordinate is fixed at 0.115, the blue coloring pigment occupies the solid content of the blue coloring composition when PB15: 6 is used in a proportion of 85% by weight or less. It has been found that the concentration can be reduced to half or less of PB15: 6 alone.

  That is, for the photocurable color composition mainly composed of an organic pigment, an acrylic transparent resin, a photocrosslinking agent, and a solvent used for the colored layer constituting the blue pixel, the colored layer constituting the blue pixel is formed. By adding PV23 as a purple coloring pigment to a blue coloring composition using at least PB15: 6 as an organic pigment, the content of PB15: 6 in the blue coloring composition is greatly reduced, thereby reducing the blue color. It has been found that elution of copper ions from the coloring composition can be reduced.

Specifically, the elution amount of copper ions with respect to NMP is 100 wt.% Of the total amount of PB15: 6 and PV23 contained in the blue coloring composition with respect to 11.2 ng / cm ^{2 in} the case of PB15: 6 alone. When PB15: 6 is 90% by weight or less, the copper ion elution amount is 4.2 ng / cm ² or less, and when PB15: 6 is 85% by weight or less, the copper ion elution amount is It became 3.6 ng / cm < ² > or less, and it discovered that it reduced significantly.

  However, if the amount of PV23 added is increased, the violet color becomes darker. Therefore, increasing the amount of PV23 unnecessarily impairs the intended blue hue. Therefore, when the film thickness is 2 μm and the y-axis value of the CIE chromaticity coordinate is 0.115, the blue color pigment concentration in the required solid content is less than half, and the x-axis value of the CIE chromaticity coordinate is As a result of examining the ratio of PB15: 6 and PV23 in the blue coloring composition so as to be within the range of 0.134 to 0.149, the total amount of PB15: 6 and PV23 contained in the blue coloring composition was 100. It is necessary to contain the blue coloring pigment in the range from 79% by weight to 85% by weight when the weight is set.

In the present invention, a configuration in which the color filter is in direct contact with the liquid crystal is proposed for simplicity and low cost. In a horizontal electric field type liquid crystal display device, if the elution amount of the copper ions is 4.3 ng / cm ² or more, there is a tendency that minute foreign substance defects are easily formed on the color filter surface. In particular, when it greatly exceeds 6 ng / cm ² , the minute foreign matter tends to cause a display defect called “bright spot”. The present inventors have not yet determined the mechanism of the formation of this minute foreign matter, but have found a strong correlation with the elution amount of copper ions.

  The color filter of the present invention can be particularly preferably applied to a color filter having a blue colored layer (that is, RGB system). Needless to say, the present invention can also be applied to a color filter in which YMC is arranged on the same substrate in addition to RGB.

  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 pixels as necessary. In the color filter of the present invention, since components eluted from the colored layer are suppressed, it is not necessary to provide an overcoat layer that covers the colored layer, leading to cost reduction. In addition, since the distance between the liquid crystal and the pixel becomes closer, the viewing angle is improved and a high-definition liquid crystal display device can be provided.

As described above, in the color filter of the present invention, it is not necessary to provide an overcoat layer on the pixel in order to supplement the solvent resistance of the colored layer, but other than supplementing chemical resistance such as the purpose of flattening the color filter. For the purpose, a resin layer can be provided. In this case, the thickness as in the conventional overcoat layer is not necessarily required.

  The transparent substrate used in 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 used for liquid crystal display devices such as a plastic substrate such as PET or a glass substrate, a glass substrate is usually used. In the case of using a light shielding pattern, it is only necessary to use a metal thin film such as chrome or a pattern made of a light shielding resin previously attached to the transparent substrate by a known method.

  The pixel may be formed on the transparent substrate by any known method such as an inkjet method, a printing method, a photolithography method, or an etching method. However, in consideration of high definition, controllability and reproducibility of spectral characteristics, a colored composition in which a pigment is dispersed in a suitable solvent together with a photoinitiator and a polymerizable monomer in a transparent resin is formed on a transparent substrate. A photolithographic method is preferred in which a colored layer is formed by coating and forming, and a step of forming a pixel of one color by pattern exposure, development, and baking of the colored layer is repeated for each color to produce a color filter.

  When the colored layer constituting the pixel included in the color filter of the present invention is prepared by preparing a photosensitive coloring composition by a photolithography method, for example, the following method is used. A pigment 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 shown by color index numbers.

  Examples of the red coloring composition for forming the red filter segment (pixel) include 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, 254, 255, Red pigments such as H.264, 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 the green filter segment 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.

  The blue coloring composition for forming the blue filter segment mainly includes C.I. I. Pigment Blue 15: 6 and C.I. I. In addition to Pigment Violet 23, for example, C.I. I. Blue pigments such as Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 22, 60, 64, and 80 can be used. In addition, C.I. I. Pigment Violet 1, 19, 27, 29, 30, 32, 37, 40, 42, 50, and other purple pigments can be used in combination.

  In combination with the organic pigment, an inorganic pigment may be used in combination in order to ensure good coatability, sensitivity, developability and the like while balancing saturation and lightness. Inorganic pigments include yellow lead, zinc yellow, red bean (red iron oxide (III)), cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green and other metal oxide powders, metal sulfide powders, metal powders, etc. Can be mentioned. Furthermore, for color matching, a dye can be contained within a range that does not lower the heat resistance.

  The transparent resin used for 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 in admixture of two or more monomers or oligomers that are precursors thereof that are cured by irradiation with radiation to produce 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.

  Examples of the polymerizable monomer that can be used as the photocrosslinking agent include caprolactone-modified dipentaerythritol hexaacrylate having a caprolactone-modified site. These can be used alone or in combination of two or more, and for the purpose of keeping the photocurability appropriate, other polymerizable monomers and oligomers can be mixed and used as necessary.

Other polymerizable monomers and oligomers include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, β-carboxyethyl (Meth) 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 , Pentaerythritol tri (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate , Neopentyl glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, ester acrylate, (meth) acrylic acid ester of methylolated melamine, epoxy (meth) acrylate , Various acrylates and methacrylates such as 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. Also about these, it can use individually or in mixture of 2 or more types.

  Generally, in order to suppress the elution of PB15: 6, it is relatively effective to increase the amount of the photocrosslinking agent with respect to the transparent resin among the components of the colored composition, and the necessary photocurability is ensured. This is also preferable. However, if the photocrosslinking agent is increased unnecessarily, the toughness of the colored layer to be formed is impaired, and there is a problem that cracks (cracks) are likely to occur due to chemicals and heat. The amount of the photocrosslinking agent used is preferably 5 to 20% by weight, more preferably 10 to 15% by weight, based on the total solid content of the colored composition.

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.

  It is also possible to add a thermal crosslinking agent. Increasing the amount of the thermosetting agent can suppress elution of PB15: 6 without impairing the toughness of the formed colored layer. However, unnecessarily increasing the amount of the thermal crosslinking agent impairs the photocurability of the colored composition.

Examples of the thermal crosslinking agent include epoxy resins and melamine resins. The epoxy resin is a compound having at least one epoxy group in the molecule. For example, an alicyclic epoxy resin, a polyalcohol type epoxy resin, a polyglycol type epoxy resin, a bisphenol A or F type epoxy resin, tetrahydroxyphenyl Ethane type epoxy resin, polyolefin type epoxy resin, phenol novolac epoxy resin, methylenecyclohexane oxide, cycloheptene epoxide, 1,2-epoxycyclohexane, glycerol / polyglycidyl ether, trimethylolpropane / polyglycidyl ether, resorcin / diglycidyl Ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol (polyethylene glycol) There is a glycidyl ether, and the like. Any of these may be used alone or in admixture of two or more. Moreover, a melamine resin can also be mixed and used as needed. 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. Also about these, it can use individually or in mixture of 2 or more types. Moreover, an epoxy resin can also be mixed and used as needed.
Moreover, as the usage-amount of a thermal crosslinking agent, 5-25 weight% is preferable on the basis of the total solid content of a coloring composition, More preferably, it is 10-20 weight%.

  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, but it is not limited to these as long as it can be applied on the substrate with a uniform film thickness. 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 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, dried and post-baked 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.

  Specific examples of the present invention will be described below.

<Preparation of coloring composition>
A mixture of the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a blue pigment dispersion.
Blue pigment: C.I. I. Pigment Blue 15: 6
(Lionol Blue ES manufactured by Toyo Ink Co., Ltd.) 3.6 parts Dispersant (Solves Birds 20000 manufactured by Zeneca) 0.6 parts Acrylic varnish (solid content 20%) 22.1 parts Thereafter, a mixture having the following composition Was stirred and mixed so as to be uniform, and then filtered through a 5 μm filter to obtain a blue colored composition.
・ Dispersion of blue pigment 26.3 parts ・ Acrylic transparent resin 9.4 parts ・ Monomer (Aronix M-402 manufactured by Toa Gosei Co., Ltd.) 4.7 parts ・ Photopolymerization initiator TPP 0.4 part ・ Photopolymerization initiator (Irg.379 manufactured by Ciba Geigy) 1.4 parts sensitizer (Kayacure DETX-S manufactured by Nippon Kayaku Co., Ltd.) 0.2 parts Leveling agent (BYK-323) 1.0 part PGMAc (propylene glycol monomethyl ether acetate) 11.0 parts · EEP (ethyl 3-ethoxypropionate) 20.0 parts · cyclohexanone 26.0 parts The blue colored composition 1 has a solid content ratio of 15% and a pigment concentration of 27%. After stirring and mixing uniformly, using a glass bead having a diameter of 1 mm, dispersing with a sand mill for 5 hours, and then filtering with a 5 μm filter, a purple pigment dispersion was prepared. .
Purple pigment: C.I. I. Pigment Violet 23
(BASF Paliogen Violet 5890) 5.6 parts Dispersant (Zeneca Sols Birds 20000) 1.0 part Acrylic varnish (solid content 20%) 34.4 parts Thereafter, a mixture having the following composition is homogenized. After stirring and mixing as described above, the mixture was filtered through a 5 μm filter to obtain a purple colored composition.
-41.0 parts of the above violet pigment dispersion-4.1 parts of acrylic transparent resin-4.7 parts of monomer (M-402)-0.4 part of TPP (polyphenylphosphine)-photoinitiator (Irg. 379) ) 1.4 parts sensitizer (DETX-S) 0.2 parts BYK-323 1.0 part PGMac 24.4 parts EEP 20.0 parts cyclohexanone 2.8 parts Purple colored composition 1 has a solid content ratio of 15% and a pigment concentration of 27% <Preparation of Color Filter>
100% by weight to 0% by weight, 95% by weight to 5% by weight, 90% by weight to 10% by weight, 85% by weight to 15% by weight, 80% by weight to 20% A mixed solution is made in the proportions of wt%, 75 wt% to 25 wt%, 70 wt% to 30 wt%. To each of these solutions, a transparent resin, a photocrosslinking agent, a solvent, and the like are added to obtain a pigment concentration in the solid content required when the film thickness is 2 μm and the value of the y-axis of the CIE chromaticity coordinate is 0.115. The liquid was prepared and a color filter was produced using this.

  On a well-washed glass substrate, the blue colored composition prepared at each ratio described above was applied by spin coating so that the film thickness after heat curing was 2 μm. These were dried and then exposed, developed with an alkaline developer, heat cured, and a blue colored layer was formed on the glass substrate.

<Extraction and atomic absorption analysis>
Each color filter produced by the above method was placed on a heated hot plate, 0.5 ml of NMP was dropped thereon, covered with a silicon wafer from which the oxide film was removed, and heated at 50 ° C. for 15 minutes. Thereafter, 4.5 ml of ultrapure water was used to wash away components eluted on the silicon wafer, and this eluate was mixed with 5 ml of ethanol. Using the solution obtained here, the elution amount of copper ions was measured with an atomic absorption spectrometer (SIMA6000, manufactured by PERKIN ELMER). Table 1 shows the results.

表１に示すように、青色着色顔料に紫色着色顔料を添加させた青色着色組成物のＮＭＰに対する銅イオンの溶出量は紫色着色顔料濃度が増加するにつれ低減する。また、ＣＩＥ色度座標のｙ軸の値を０．１１５としたとき、紫色着色顔料濃度が増加するにつれ、固形分中の青色顔料濃度を低減でき、銅イオンの溶出の低減が可能となった。尚、コントラストを考慮に入れて考えると、青色着色組成物に含まれる紫色着色顔料の割合は１５％が最適である。

As shown in Table 1, the elution amount of copper ions with respect to NMP of the blue coloring composition obtained by adding the purple coloring pigment to the blue coloring pigment decreases as the concentration of the purple coloring pigment increases. When the y-axis value of the CIE chromaticity coordinate is 0.115, the blue pigment concentration in the solid content can be reduced as the purple pigment concentration increases, and the elution of copper ions can be reduced. . When the contrast is taken into consideration, the optimal ratio of the purple coloring pigment contained in the blue coloring composition is 15%.

  Moreover, as shown in Table 1, the elution amount of copper ions can be reduced as the purple pigment ratio is increased. However, when the violet pigment ratio exceeds 21%, the x coordinate of chromaticity becomes a value of 0.15 or more, resulting in a purple color and a reduction in image quality. Therefore, in order to secure the color of the blue pixel, the pigment ratio of the blue coloring pigment needs to be added by 79% by weight or more.

Claims (3)

In a color filter having a plurality of color pixels including a blue pixel on a transparent substrate and not provided with a protective layer made of a transparent resin, N-methyl-2-copper ions from a colored layer constituting the blue pixel A color filter having an elution amount with respect to pyrrolidinone of 4.2 ng / cm ² or less.   The organic pigment of the colored layer constituting the blue pixel is C.I. I. Pigment Blue 15: 6 was added to a blue coloring composition as a purple coloring pigment. I. Pigment Violet 23 is added, and when the total amount of the blue color pigment and the purple color pigment contained in the blue color composition is 100% by weight, the amount of the blue color pigment is 79% by weight to 85% by weight. The color filter according to claim 1, wherein the color filter is in a range of% or less.   3. A liquid crystal display device having a structure in which a liquid crystal is sandwiched between two substrates and a color filter is in direct contact with the liquid crystal, wherein the color filter according to claim 1 or 2 is provided. .