JP2007304392A - Color filter and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter in which the electrical properties of colored layers constituting the color filter cause neither faulty liquid crystal alignment nor threshold deviance of switching, and which can therefore ensures satisfactory performance without disposing a protective layer (overcoat layer) of a transparent resin. <P>SOLUTION: The color filter comprises a plurality of color pixels on a transparent substrate, wherein a colored layer constituting at least one color pixel is formed using a colored resin composition containing a resin with a dielectric loss tangent (tanδ) of ≤0.008 in a frequency range of 10-100 Hz. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter for a liquid crystal display device, and in particular, a horizontal electric field method in which a pixel formation surface faces a liquid crystal sandwiching surface and is incorporated in a liquid crystal display device without an electrode between a pixel and a liquid crystal In liquid crystal display devices, the electrical properties of the colored layer of the color filter do not adversely affect the switching performance of the liquid crystal, and sufficient reliability can be ensured without the provision of a protective layer (overcoat layer) made of transparent resin. It relates to a color filter that can be used.

  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 systems (TN systems) and Vertical Alignment systems (VA systems), the horizontal electric field type liquid crystal display device has no electrodes on the colored layer of the color filter, so the liquid crystal molecules are the material of the colored layer. There is a problem in that it is directly affected by the electrical characteristics.
In fact, when a conventional colored layer material is used, various display defects such as poor liquid crystal alignment due to the electrical characteristics of the colored layer material and a seizure phenomenon due to a shift in the switching threshold have occurred in a horizontal electric field type liquid crystal display device. It was. Therefore, when a color filter made of a conventional colored layer material is used in a horizontal electric field type liquid crystal display device, a protective layer (overcoat layer) made of a transparent resin is provided on the colored layer so that the liquid crystal sandwiching surface and the colored layer do not directly touch each other. It is common to do so.

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, by providing an overcoat layer made of a transparent resin, it is possible to use a conventional colored layer material in a horizontal electric field type liquid crystal display device, but various display defects occur even when an overcoat layer is used. (For example, refer to Patent Document 1). Both the colored layer material and the overcoat layer material have been improved so as to be compatible with the horizontal electric field type liquid crystal display device, but the overcoat layer has a thickness of 2 μm or more in some cases in order to ensure sufficient performance. Therefore, there is a problem that it is difficult to apply uniformly, which is one factor that hinders cost 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.
JP 2004-117537 A JP 2004-297292 A

The present invention has been made in order to solve the above-described problems. In particular, the pixel formation surface of the color filter faces the liquid crystal sandwiching surface, and is incorporated in the liquid crystal display device without an electrode between the pixel and the liquid crystal. In a horizontal electric field type liquid crystal display device, a transparent resin protective layer (overcoat layer) does not adversely affect liquid crystal alignment defects and switching threshold shifts due to the electrical properties of the colored layers constituting the color filter. It is an object of the present invention to provide a color filter that can ensure a sufficient performance without providing a mask.

  The present invention relates to a color filter comprising a plurality of color pixels on a transparent substrate, wherein a colored layer constituting at least one color pixel has a dielectric loss tangent (tan δ) of 0.008 or less in a frequency range of 10 Hz to 100 Hz. It is a color filter formed using the coloring resin composition containing this.

  Further, the present invention provides the color filter according to the above invention, wherein the resin is obtained by further reacting a reaction product of an epoxy resin and an unsaturated group-containing carboxylic acid or its anhydride with a polybasic carboxylic acid or its anhydride. A color filter characterized by being a photopolymerizable unsaturated group-containing resin or a resin having a phenolic hydroxyl group.

  Further, the present invention is the color filter according to the above invention, wherein the color layer has a dielectric loss tangent (tan δ) of 0.03 or less in a frequency range of 10 Hz to 100 Hz.

  According to the present invention, in the color filter according to the above invention, the one color pixel is a green pixel.

  Further, the present invention is the color filter according to the above invention, wherein the pixels other than the green pixel are red pixels and / or blue pixels.

  Moreover, the present invention is the color filter according to the above invention, wherein the relative permittivity of the colored layer is 5.0 or less in a frequency range of 10 Hz to 100 Hz.

  The present invention is the color filter according to the invention, wherein the colored layer does not have a protective layer.

  Moreover, the present invention is a liquid crystal display device using the color filter according to any one of claims 1 to 7.

  The present invention is a color filter in which a colored layer is formed using a colored resin composition containing a resin whose dielectric loss tangent is 0.008 or less in a frequency range of 10 Hz to 100 Hz. When used, it is a color filter that does not have a protective layer (overcoat layer) made of a transparent resin, does not have a liquid crystal alignment defect, and does not shift a switching threshold, that is, does not adversely affect display performance.

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

As a result of various studies on the relationship between the electrical properties of the color filter and the display defect in the horizontal electric field type liquid crystal display device, the present inventor has found that the liquid crystal alignment defect and the switching threshold shift of the horizontal electric field type liquid crystal display device are mainly colored layers. It was found that this was caused by the dielectric properties of
Specifically, it can be explained by the value of dielectric loss tangent. It is based on the following mechanism. The dielectric loss tangent (tan δ) is the ratio between the amount of charge accumulated in the dielectric and the amount of charge consumed. When the dielectric loss tangent is relatively small, the electric charge accumulated in the dielectric is retained, whereas when it is relatively large, the electric charge is consumed and not retained.

  FIG. 1 is a schematic cross-sectional view of a horizontal electric field type liquid crystal display device. In the horizontal electric field type liquid crystal display device 20, the colored layer 2 constituting the color filter 10 is arranged so as to face inward, and is contained in the liquid crystal driving electric field 6. If the value of the dielectric loss tangent of the colored layer differs greatly from the dielectric loss tangent of the members (liquid crystal, alignment film, etc.) in other cells, a phenomenon that the charge retention state of the liquid crystal molecules becomes non-uniform occurs.

  Due to the non-uniform state of charge retention, a vertical electric field that should not be generated in a horizontal electric field type liquid crystal display device is generated, resulting in liquid crystal alignment failure, or excessive charge remaining. Display defects such as burn-in due to threshold shift. Therefore, the dielectric loss tangent of the colored layer constituting the color filter is an important characteristic that determines the display characteristics of the horizontal electric field type liquid crystal display device. The dielectric loss tangent is a value depending on the measurement frequency, but since one frame for driving the liquid crystal is about 60 Hz, attention is paid to the dielectric loss tangent at a period (second), that is, a frequency around 30 Hz, and a frequency of about 10 to 100 Hz. Is appropriate.

  Here, the measurement results of the dielectric loss tangent of several kinds of colored layers used in the conventional color filter are shown in FIG. 2, FIG. 3, and FIG. The dielectric loss tangent of the colored layer of each color constituting the conventional color filter is in the range of 10 Hz to 100 Hz, and shows a value of about 0.006 to 0.25 depending on the type of the colored layer. As shown in FIG. 3, in particular, the green colored layer has a large dielectric loss tangent, and in fact, at least in the green colored layer, if the overcoat layer is not provided at the boundary with the liquid crystal sandwiching surface, the liquid crystal alignment failure and switching It was easy for the threshold deviation of the above to occur remarkably.

  The present inventor has provided an overcoat layer at the boundary between the colored layer and the liquid crystal sandwiching surface in a color filter used in a liquid crystal display device, particularly a lateral alignment type liquid crystal display device in which no electrode is provided between the colored layer and the liquid crystal. In order to provide a color filter that can improve the display quality by eliminating liquid crystal alignment failure and switching threshold shift without being provided, various studies have been made on the improvement of this characteristic dielectric property.

  In general, a liquid crystal, an alignment film, or the like is formed using a material having a large ability to hold charges, that is, a dielectric tangent is relatively small, and its value is generally about 0.005 to 0.02. Therefore, it is considered that the value of the dielectric loss tangent of the colored layer provided in the color filter used in the horizontal electric field type liquid crystal display device is preferably the same value as that of the liquid crystal and the alignment film.

  That is, in the multicolored color filter for liquid crystal display devices, the dielectric loss tangent of the colored layer constituting the pixel provided in the color filter is about 0.03 or less, more preferably 0.02 or less, in the range of 10 Hz to 100 Hz. Thus, it has been found that deterioration in display quality such as pixel orientation failure and threshold deviation can be effectively prevented without providing an overcoat layer on the pixel. The lower the dielectric loss tangent of the colored layer is, the more preferable, but the lower limit is about 0.005 to 0.006 at present due to the characteristics of the material of the colored layer.

  As a result of various studies, it has been found that in the color filter of the present invention, it is preferable that the relative dielectric constant of the colored layer is 5.0 or less in the frequency range of 10 Hz to 100 Hz. The relative permittivity is an index of the amount of charge accumulated in the dielectric, and if the value is significantly large in the colored layer, the balance of the amount of charge accumulated between the members in the cell (liquid crystal, alignment film, etc.) is greatly disrupted. Thus, display failure such as burn-in occurs due to a deviation of the switching threshold. Therefore, the relative dielectric constant of the colored layer of the color filter needs to be 5.0 or less, more preferably 4.5 or less at a frequency of 10 Hz to 100 Hz. A lower relative dielectric constant is preferable, but about 3.0 is the lower limit at the present time due to material characteristics.

  Conventionally, as a method for realizing these characteristics, for example, in Patent Document 1 or 2, the concentration of a pigment that is a component having a high dielectric loss tangent is set to a certain level or less, the purity of the pigment is improved, and the dielectric loss tangent of the pigment itself is set. It has been reported to be smaller.

  However, since these methods limit the degree of freedom in selecting a pigment, it may be difficult in terms of labor, time, and cost to meet various color characteristic requirements. Therefore, as a result of intensive studies, the present inventor formed a colored layer using a colored resin composition containing a resin having a dielectric loss tangent of 0.008 or less, whereby the dielectric loss tangent of the colored layer was 0.03 or less. It has been found that it is easily possible to suppress it. This broadens the range of pigment selections, making it easy to provide color filters with color characteristics that meet various required specifications, thereby speeding up development and reducing development and material costs. Is also connected.

Hereinafter, a method for obtaining the color filter of the present invention will be described.
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 composed of at least a colored layer. Multiple colors include combinations of red, green, blue (RGB) and yellow, magenta, cyan (YMC). The color filter of the present invention is different from a color filter having a green colored layer (ie, RGB system). It can be applied particularly preferably.

  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. Since the color filter of the present invention does not affect the electric characteristics of the colored layer in the liquid crystal driving electric field, it is not necessary to provide an overcoat layer covering the colored layer, so that the yield is good and the cost is reduced. 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 in order to supplement the electrical characteristics of the colored layer, but a resin layer can be provided for the purpose of flattening the color filter. In this case, the thickness as in the conventional overcoat layer is not necessary.

  The transparent substrate used in the method 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. 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.

  As a method for producing the colored layer on the transparent substrate, any method such as a known ink jet method, printing method, photoresist method, etching method may be used. However, considering high definition, controllability and reproducibility of spectral characteristics, etc., a colored resin 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 coating film is formed on the coating film, and a process of forming a colored layer of one color by pattern exposure and development on the coating film 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 photolithography by preparing a colored resin composition, for example, the following method is used. 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 resin composition of the present invention are indicated by color index numbers.

  Examples of the red colored resin composition for forming the red filter segment (colored layer) 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 colored resin 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 3,174,175,176,177,179,180,181,182,185,187,188,193,194,199,213,214, 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 colored resin 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 colored resin composition can be used in combination with the same yellow pigment as the red colored resin composition.

Examples of the blue colored resin composition for forming the blue filter segment include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 80, etc., preferably C.I. I. Pigment Blue 15: 6 can be used.
The blue colored resin composition includes C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like, preferably C.I. I. Pigment Violet 23 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 that can be used in the colored resin composition of the present invention preferably has a transmittance of 80% or more, more preferably 95% or more, and a dielectric loss tangent in the entire wavelength region of 400 to 700 nm in the visible light region. This resin is 0.008 or less in the frequency range of 10 Hz to 100 Hz. 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 such resins include polyester resins, polystyrene, styrene-maleic acid copolymers, polyimide resins, epoxy resins, benzoguanamine resins, melamine resins, urea resins, novolac resins, polyvinylphenol resins, and modified ones thereof. Etc. Among these, a photopolymerizable unsaturated group-containing resin obtained by further reacting a reaction product of an epoxy resin and an unsaturated group-containing carboxylic acid or its anhydride with a polybasic carboxylic acid or its anhydride, or a novolak A resin, a resin having a phenolic hydroxyl group such as a polyvinylphenol resin, or a modified resin thereof is particularly preferable from the viewpoint of developability, patterning characteristics, cost, and the like.

  Polymerizable monomers and oligomers that can be used 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) a Chryrate, 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) Various acrylates and methacrylates such as acrylate and urethane acrylate, (meth) acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxymethyl ( And (meth) acrylamide, N-vinylformamide, acrylonitrile and the like. These can be used alone or in admixture of two or more.

When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the colored resin 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 resin 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 colored resin 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 resin 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.

  The colored resin 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 colored resin 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 colored resin composition is applied and the colored layer is formed 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. In addition, it is preferable to perform a post-baking at 180 to 260 degreeC for about 15 to 60 minutes.

  By repeating the above-described series of steps by changing the colored resin composition and the 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.

[Synthesis of Modified Epoxy Resin Solution (A-1)]
An epoxy compound obtained by adding 17.9 g of acrylic acid and 27.2 g of phenol to 100 g of bisphenol A type epoxy resin by a known method was reacted with 38.7 g of biphthalic anhydride by a known method. This was adjusted with cyclohexanone to a solid content concentration of 20% to obtain a modified epoxy resin solution (A-1) having a photopolymerizable unsaturated group. (Mw = 4600, acid value (solid content) 81 mgKOH / g, viscosity 59.6 mPa · s, solid content 37.5%).

[Synthesis of Modified Epoxy Resin Solution (A-2)]
57.5 g of the product obtained by purifying after reacting 70.5 g of biphenyl cyclohexyl ketone and 200.7 g of excess phenol by a known method is reacted with 195.8 g of epichlorohydrin, and the solvent is distilled off. As a result, 57 g (yield 79%) of 1,1-bis (4′-epoxypropyloxyphenyl) -1- (1 ″ -biphenyl) -1-cyclohexylmethane (hereinafter also referred to as compound a) was obtained. . (Melting point 64.2 ° C., epoxy equivalent 282, n = 0.04). An epoxy compound obtained by adding 1695 g of the compound a obtained by the above-mentioned method, 443 g of acrylic acid, and 6 g of 2,6-di-tert-butyl-p-cresol by a known method, and 482 g of succinic anhydride in a known method And reacted. This was adjusted with cyclohexanone to a solid content concentration of 20% to obtain a modified epoxy resin solution (A-2) having a photopolymerizable unsaturated group. (Mw = 4200, Mn = 2100, acid value (solid content) 55 mgKOH / g).

[Preparation of colored resin composition]
Red, blue and green colored resin compositions were prepared in the following manner.
<Red colored resin composition>
A mixture having 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 red pigment dispersion.

Red pigment: C.I. I. Pigment Red 254 18 parts ("Ilgar Forred B-CF" manufactured by Ciba Specialty Chemicals)
Red pigment: C.I. I. Pigment Red 177 2 parts (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals)
Dispersant ("Ajisper PB821" manufactured by Ajinomoto Fine-Techno Co., Ltd.) 2 parts Modified epoxy resin solution (A-1) 108 parts After that, the mixture of the following composition was stirred and mixed uniformly, and then filtered through a 5 μm filter. A red colored resin composition was obtained.

130 parts of the above dispersion 13 parts of trimethylolpropane triacrylate
("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 3 parts sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 1 part Cyclohexanone 253 parts.

<Blue colored resin composition>
A mixture having 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 50 parts
("Rionol Blue ES" manufactured by Toyo Ink Co., Ltd.)
Purple pigment: C.I. I. Pigment Violet 23 2 parts
(BASF "Paliogen Violet 5890")
Dispersant (“Solvers Bird 20000” manufactured by Zeneca) 6 parts Modified Epoxy Resin Solution (A-1) 200 parts Thereafter, the mixture having the following composition is stirred and mixed to be uniform, and then filtered through a 5 μm filter to give a blue color. A resin composition was obtained.

268 parts of the above dispersion 19 parts of trimethylolpropane triacrylate (“NK ester ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 4 parts sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts 214 parts cyclohexanone.

<Green colored resin composition 1>
A mixture having 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.

Green pigment: C.I. I. Pigment Green 36 16 parts
(Toyo Ink Manufacturing Co., Ltd. “Rionol Green 6YK”)
Yellow pigment: C.I. I. Pigment Yellow 150 8 parts
(Bayer's "Funcheon First Yellow Y-5688")
Dispersant ("Disperbyk-163" manufactured by Big Chemie) 2 parts Modified epoxy resin solution (A-1) 100 parts Thereafter, the mixture having the following composition was stirred and mixed to be uniform, then filtered through a 5 µm filter and green. A colored resin composition was obtained.

128 parts of the above dispersion 14 parts of trimethylolpropane triacrylate (“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy Co., Ltd.) 4 parts sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts Cyclohexanone 257 parts <Green Colored Resin Composition 2>
A green colored resin composition 2 was obtained in the same manner as in the <green colored resin composition 1> except that the modified epoxy resin solution (A-2) was used instead of the modified epoxy resin solution (A-1). .

<Green colored resin composition 3>
Instead of the modified epoxy resin solution (A-1), a resin solution (A-3) in which 20 g of cresol novolac resin (manufactured by Asahi Organic Materials Co., Ltd., product name: EP0010A) was dissolved in 80 g of cyclohexanone was used. Green colored resin composition 3 was obtained in the same manner as green colored resin composition 1>.

<Green colored resin composition 4>
Instead of the modified epoxy resin solution (A-1), a resin solution (A-4) in which 20 g of poly (p-vinylphenol) (manufactured by Maruzen Petrochemical Co., Ltd., product name; Marcalinker MS-1) was dissolved in 80 g of cyclohexanone. ) Was used in the same manner as in <Green Colored Resin Composition 1> to obtain Green Colored Resin Composition 4.

[Comparative example]
<Green colored resin composition 5>
Instead of the modified epoxy resin solution (A-1), 20 g of a resin (molecular weight of about 35000) obtained by copolymerizing benzyl methacrylate / styrene / methacrylic acid (copolymerization ratio 60/10/30) by a known method was added to 80 g of cyclohexanone. A green colored resin composition 5 was obtained in the same manner as in <Green colored resin composition 1> except that the dissolved resin solution (A-5) was used.

<Green colored resin composition 6>
Instead of the modified epoxy resin solution (A-1), butyl methacrylate / methacrylic acid / -2-hydroxyethyl methacrylate / methacrylic acid-2-isocyanatoethyl copolymer (copolymerization ratio 20/20/40/20 The same as the above <green colored resin composition 1> except that a resin solution (A-6) in which 20 g of a resin (molecular weight of about 35000) copolymerized by a known method was dissolved in 80 g of cyclohexanone was used. Thus, a green colored resin composition 6 was obtained.

[Production of color filter]
A color filter was prepared in the following manner using the obtained red colored resin composition, blue colored resin composition, and green colored resin composition. As the green colored resin composition, green colored resin compositions 1 to 6 were used, and Examples 1 to 4 and Comparative Examples 1 and 2 were used.

  The red colored resin composition was applied on a glass substrate by spin coating so as to have a film thickness of 2 μm. After drying, striped pattern exposure was performed with an exposure machine, and development was performed with an alkali developer for 90 seconds. Subsequently, post-baking was performed in an oven at 210 ° C. for 30 minutes to form red pixels, which are striped colored layers, on a transparent substrate. The alkaline developer has the following composition. In the following examples and comparative examples, development is performed using this alkaline developer.

Sodium carbonate 1.5% by weight
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 colored resin composition is similarly applied by spin coating so that the film thickness becomes 2 μm.
After drying, the striped colored layer was exposed to a position shifted from the above-mentioned red pixel with an exposure machine, and post-baked after development to form 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 colored resin composition. Thus, a color filter having striped pixels of three colors of red, green, and blue on the transparent substrate was obtained.

  For the color filters of Examples 1 to 4 and Comparative Examples 1 and 2, the name of the resin solution used, the value of the dielectric tangent of the resin, and the value of the dielectric tangent of the colored layer constituting the green pixel are shown in Table 1. 5 is plotted in FIG. The value at 20 Hz was used as the representative value for the dielectric loss tangent.

緑色着色層の誘電正接は樹脂の誘電正接に大きく依存し、樹脂の誘電正接が０．００８を超えると緑色着色層の誘電正接は０．０３を上回り、樹脂の誘電正接が０．００４程度で緑色着色層の誘電正接が０．０２程度とすることができていた。

The dielectric loss tangent of the green colored layer greatly depends on the dielectric loss tangent of the resin. When the dielectric loss tangent of the resin exceeds 0.008, the dielectric loss tangent of the green colored layer exceeds 0.03, and the dielectric loss tangent of the resin is about 0.004. The dielectric loss tangent of the green colored layer could be about 0.02.

  Using the color filters of Examples 1 to 4 and the color filters of Comparative Examples 1 and 2, respectively, horizontal electric field type liquid crystal display devices were prepared. In the liquid crystal display devices using the color filters of Examples 1 to 4, As a result, good display quality was obtained without causing a liquid crystal alignment defect of the pixel and a threshold shift of the driving voltage. On the other hand, in the liquid crystal display devices using the color filters of Comparative Examples 1 and 2, image sticking occurred due to poor liquid crystal alignment and switching threshold shift, and good display characteristics could not be obtained.

It is a cross-sectional schematic diagram of a horizontal electric field type liquid crystal display device. It is a figure which shows the frequency characteristic of the dielectric loss tangent of a red colored layer. It is a figure which shows the frequency characteristic of the dielectric loss tangent of a green colored layer. It is a figure which shows the frequency characteristic of the dielectric loss tangent of a blue colored layer. It is a figure which shows the relationship between the dielectric loss tangent of resin, and the dielectric loss tangent of a colored layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Colored layer 3 ... Polarizing plate 4 ... Pixel electrode 5 ... Common electrode 6 ... Drive electric field 7 ... Liquid crystal layer 10 ... Color filter 20 ... Horizontal electric field type liquid crystal display device

Claims (8)

  In a color filter including a plurality of color pixels on a transparent substrate, a colored layer constituting at least one color pixel contains a resin whose dielectric loss tangent (tan δ) is 0.008 or less in a frequency range of 10 Hz to 100 Hz. A color filter formed using a resin composition.   The resin is a photopolymerizable unsaturated group-containing resin obtained by further reacting a reaction product of an epoxy resin and an unsaturated group-containing carboxylic acid or its anhydride with a polybasic carboxylic acid or its anhydride, or phenolic The color filter according to claim 1, wherein the color filter is a resin having a hydroxyl group.   The color filter according to claim 1 or 2, wherein a dielectric loss tangent (tan δ) of the colored layer is 0.03 or less in a frequency range of 10 Hz to 100 Hz.   4. The color filter according to claim 1, wherein the one color pixel is a green pixel.   5. The color filter according to claim 1, wherein the pixel other than the green pixel is a red pixel and / or a blue pixel.   The color filter according to claim 1, 2, 3, 4, or 5, wherein a relative dielectric constant of the colored layer is 5.0 or less in a frequency range of 10 Hz to 100 Hz. .   The color filter according to claim 1, 2, 3, 4, 5, or 6, wherein a protective layer is not provided on the colored layer.   A liquid crystal display device using the color filter according to any one of claims 1 to 7.

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