JP5600961B2 - Color filter substrate - Google Patents

Description

The present invention relates to a color filter substrate used in a liquid crystal display device and a color image pickup tube device.

  In recent years, liquid crystal display devices have been evaluated for space saving, light weight, and power saving due to their thinness. In particular, the spread to display applications such as television receivers is rapidly advancing, and it is desired to improve display performance such as brightness, contrast, and visibility in all directions, and further increase the brightness of the color filters used therefor. High contrast is desired. The display quality of liquid crystal display devices has improved year by year, and its performance has reached a level exceeding that of conventional cathode ray tubes, but improvement of white luminance remains a problem.

  In a color liquid crystal display device, light is transmitted through two polarizing plates, and the light from the backlight is usually less than 1/3 due to loss in the colored pixel layer and the optical unit for color display. Not used. In addition, since light from the backlight having uniform luminance is used on the entire display screen, there is no difference between the luminance when the entire display screen is white and the peak luminance when locally displaying white. On the other hand, in a self-luminous display such as a cathode ray tube, the luminance can be increased by reducing the display area of white, which is excellent in expressing local white display.

  With the recent increase in global environmental problems and the expansion of demand for large-sized flat-screen TVs, more and more power savings are required for liquid crystal display devices. Therefore, if the luminance of the liquid crystal display device can be improved, the luminance of the backlight can be reduced to save power. Various techniques have been proposed for improving luminance. For example, Patent Document 1 discloses RGBW including a transparent pixel (W) in addition to a red pixel (R), a green pixel (G), and a blue pixel (B). A color display device using a color filter with improved light transmittance is disclosed.

  In an active matrix liquid crystal display device, generally, a substrate in which an active element (thin film transistor, TFT) is formed for each pixel on a glass substrate, and a color filter substrate in which a color filter and a uniform transparent electrode are formed on the glass substrate. Are arranged opposite to each other with a liquid crystal interposed therebetween. The shutter action of the liquid crystal of each pixel is controlled by the switching action of each TFT element of the TFT substrate (hereinafter, the substrate on which the active element is formed is abbreviated as TFT substrate).

  In a liquid crystal display device using TFTs, a TFT substrate and a color filter substrate are arranged to face each other with a predetermined interval, and the liquid crystal is sandwiched between sealing materials in which reinforcing fibers are mixed with epoxy resin or the like. It is composed by pasting together. Liquid crystal is sealed between the color filter substrate and the TFT substrate, but if the distance between the color filter substrate and the TFT substrate is not accurately maintained, the thickness of the liquid crystal layer will differ, resulting in a difference in the optical rotation characteristics of the liquid crystal. This causes a phenomenon that coloring is caused by or a partial color unevenness occurs and the image is not displayed correctly. Conventionally, in a liquid crystal display device, in order to ensure a uniform cell gap between a TFT substrate and a color filter substrate, glass called a spacer or resin transparent spherical particles (beads) are interposed between these substrates. However, there may be a phenomenon that the spacers are not uniformly dispersed and the spacers are partially biased. When such a phenomenon occurs, the display quality of the portion where the spacers are gathered deteriorates, and there is a problem in terms of accurately maintaining the interval.

Therefore, a method of forming columnar protrusions having a diameter of 10 μm to 50 μm called spacers on the liquid crystal has been proposed. Patent Documents 2 to 5 disclose techniques for forming a spacer for a liquid crystal display device on a color filter substrate by a photolithography technique. Patent Documents 6 to 8 disclose a technique of a stacked PS (Photo Spacer) in which a spacer for a liquid crystal display device is formed by overlapping colored layers without increasing the number of processes.

  The laminated PS is usually formed by overlaying a plurality of photosensitive coloring compositions on a black matrix (BM) so as not to lower the aperture ratio of the color filter. However, since the coloring composition has poor wettability to the hard film, a repelling phenomenon occurs, and the coloring composition flows into the pixel region in the post-baking process, so that the coloring is formed on the narrow BM portion. The film thickness of the composition is thinner than the film thickness of the pixel flat portion. In addition, the conventional transparent resin composition for white pixels has high fluidity and is more difficult to ride on than the colored composition, but rather flattens the laminated portion. Therefore, the colored composition is overlapped with two colors and three colors to obtain the necessary PS stacking height, but when priority is given to the thickness of the colored pixels in order to obtain a desired hue, the stacked PS is desired. It was difficult to control the height.

Japanese Patent Laid-Open No. 10-10998 JP 9-258192 A Japanese Patent Laid-Open No. 11-248921 JP 2001-201750 A Japanese Patent Laid-Open No. 2001-108813 JP-A-4-93924 JP-A-4-184423 JP 2007-212826 A

The present invention has been made in view of the above problems, and when giving priority to the thickness of the colored pixel in order to obtain a desired hue, by applying the desired thickness of the white pixel, It is an object of the present invention to provide a color filter substrate that can adjust a difference in film thickness between a pixel portion and a portion that runs on a BM, and that can control a laminated photo spacer to a desired height.

The invention according to claim 1 of the present invention includes at least a black matrix, a plurality of colored pixels and white pixels on a substrate, and a photosensitive white composition and colored pixels constituting the white pixels on the black matrix. A color filter substrate having a laminated photo spacer formed by laminating one or more colors of the photosensitive coloring composition to constitute,
A color filter substrate comprising 5 to 40% by mass of a transparent extender pigment in the total solid content of the photosensitive white composition.

According to the color filter substrate of the present invention, by which the photosensitive white composition forming the pixel and laminated PS is contained 5 to 40% by weight of transparent extender pigment in the total solid content, the photosensitive The fluidity of the white composition can be controlled low. In the state of being stacked on the BM, the white composition is less likely to flow into the pixel region even in the post-baking process. For this reason, the climbing rate compared to the thickness of the flat pixel portion of the white composition formed on the BM portion is increased. It is possible to obtain the necessary PS stacking height by stacking photosensitive coloring compositions having a small number of colors. That is, in addition to improving the performance by obtaining a stable laminated PS height, the amount (film thickness) of the photosensitive coloring composition applied in the photolithography process can be reduced, or the number of laminated colors can be reduced. As a result, the yield can be improved and the amount of resist used can be reduced.

The schematic diagram which shows the color filter substrate of an example which formed laminated | multilayer PS of this invention in a partial cross section. The plane expansion schematic diagram of the color filter board | substrate which has a pixel of RGBW. Explanatory drawing which shows the relationship between the white pixel of the color filter board | substrate which concerns on this invention, and the film thickness of the white composition riding on BM in a cross section. The graph which shows the relationship between the transparent extender pigment ratio in the white photosensitive coloring composition concerning this invention, and a climbing rate.

  The color filter substrate of the present invention and the photosensitive white composition used therefor will be described in detail below based on one embodiment.

  The color filter substrate of the present invention is a photosensitive white composition comprising a black matrix (2) on a substrate (1), a plurality of colored pixels (3), a white pixel (4), and a white pixel on the black matrix. And a laminated photospacer (5) formed by laminating one or more colors of the photosensitive coloring composition constituting the colored pixel. The color filter substrate of the present invention is characterized in that 5 to 40% by mass of a transparent extender pigment is contained in the entire solid sentence of the photosensitive white composition. The photosensitive white composition according to the present invention is a photosensitive white composition comprising at least a transparent resin, a photopolymerizable monomer, a photopolymerization initiator, a solvent, and a transparent extender pigment, and 5 to A photosensitive coloring composition containing 40% by mass of a transparent extender pigment.

As a method for forming colored pixels and a black matrix on a transparent substrate, a pigment dispersion method has become the mainstream. In the pigment dispersion method, a color filter is formed of a plurality of colored layers (red, green, blue, etc.) by patterning a coating layer of a photosensitive coloring composition in which a coloring material such as an organic pigment is dispersed by a known photolithography method. This is a method of forming a pixel. Similarly, the white photosensitive composition of the present invention is patterned by a photolithography method using a transparent extender pigment instead of the color material. Although the order of coloration of the plurality of colored layers is not limited, a transparent white pixel is first formed using the white photosensitive composition of the present invention after the pattern formation of the black matrix layer from the convenience of alignment and the formability of the laminated PS. After that, a red pixel, a green pixel, a blue pixel, and the like are sequentially formed by applying a colored layer, exposing, developing, and the like, and simultaneously forming the pixel, a stacked PS having a desired height is formed.

  When a white (transparent) layer and a colored layer are laminated as a spacer, the laminated portion first stacks a white (transparent) layer on the black matrix layer, and then laminates one or more colored layers thereon. To do. The number of colors to be superimposed is defined by the cell gap necessary for the liquid crystal display device, but preferably two to three colors. In the case of stacking two colors, when the red and blue colored layers are stacked, the color becomes close to black, which prevents color mixture in the pixel portion when color misregistration occurs. Alternatively, by using two types of stacked portions of two colors and three colors, the lower stacked portion can be used as a sub-spacer. The sub-spacer serves as a spacer that prevents cell destruction when a large pressure is applied to the liquid crystal panel during use as a display device. The formation ratio of the spacer and the sub-spacer is not limited, but about 1: 2 (the latter is the sub-spacer) is practical. Alternatively, for example, it can be formed as a laminated portion of two colors, and can be used as a spacer or a sub-spacer depending on whether or not a protrusion is further formed on the laminated portion.

  In a normal color filter substrate, the black matrix layer has a thickness of 0.5 to 3 μm and a width of 3 to 30 μm. The thickness (thickness) of each of the white pixel, red pixel, green pixel, and blue pixel is 0.5 to 3 μm. This film thickness largely depends on the composition of the photosensitive white composition or the photosensitive coloring composition and the coating method. However, the white layer (transparent layer), red layer, green layer, and blue layer that is formed on the black matrix. The thickness of the layer tends to be thinner than the pixel thickness of the flat portion. Therefore, the resin composition flowing into the pixel flat portion increases the film thickness in the vicinity of the pixel portion and the stacked PS, resulting in a problem that the stacked PS is lowered and the cell gap is difficult to control.

  The black matrix layer, which is the basis of the stacked PS, is a thin light-shielding pattern formed between the pixels in order to increase the contrast of a liquid crystal display device formed using a black resin. As a method of forming the black matrix layer, a protective resist is formed by a photolithography method using a black non-photosensitive resin, and a matrix or stripe is formed by etching, or by a photolithography method using a black photosensitive resin. There is a method of forming a matrix or stripe. As the black color material, carbon black, titanium oxide, or a plurality of organic pigments can be used.

  As described above, the photosensitive white composition according to the present invention includes at least a transparent resin, a photopolymerizable monomer, a photopolymerization initiator, a solvent, and a transparent extender pigment. The photosensitive white composition is prepared by adding 5 to 40% by mass of a transparent extender pigment in the total solid sentence. The black photosensitive resin and photosensitive coloring composition used for the formation of the black matrix and the colored pixel are, for example, a pigment component dispersed in a transparent resin binder using a dispersant, and a photopolymerizable monomer and photopolymerization in this dispersion. It is prepared by adding an initiator, a sensitizer, a solvent and the like.

The black photosensitive resin used for forming the black matrix, the photosensitive coloring composition used for forming the colored pixels, and the photosensitive white composition of the present invention are mainly composed of a resin binder and an initiator, and the resin binder is photopolymerized, or It undergoes three-dimensional crosslinking through thermal polymerization or photopolymerization and thermal polymerization. By three-dimensionally crosslinking the resin binder of the black matrix, the coloring composition, and the white composition, it is possible to suppress the thickness of the black matrix, the coloring pixels, the white pixels, and the laminated PS from being reduced due to the load in the panel assembly process.

  Examples of resin binders suitable for photopolymerization include acrylate resins, examples of resin binders suitable for thermal polymerization include epoxy resins, and examples of resin binders suitable for photopolymerization and thermal polymerization include epoxy acrylate resins. It is done.

  The transparent extender pigment contained in the photosensitive white composition of the present invention may be at least one selected from the group consisting of silicon oxide (silica), barium sulfate, aluminum oxide, calcium carbonate, and magnesium carbonate. Moreover, it is preferable that the average particle diameter of an extender is 500 nm or less from a transparency point. In particular, fine powder silica gel having a refractive index close to that of a binder resin, excellent dispersibility in the resin, and exhibiting thickening can be more preferably used.

  In the photosensitive white composition of this invention, 5-40 mass% transparent extender pigment is contained with respect to the total solid of a photosensitive white composition. If the amount of the transparent extender pigment contained in the total solid content of the photosensitive coloring composition is less than 5% by mass, the effect of increasing PS by thickening is insufficient. There arises a problem that the cross-sectional shape of the coating of the portion becomes a reverse taper. On the other hand, if the solid content of the transparent extender pigment exceeds 40% by mass, the photopolymerizable monomer and photopolymerization initiator must be reduced, and pixel formation becomes impossible.

  As described above, by containing a transparent extender pigment in the photosensitive white composition, the fluidity of the photosensitive white composition can be controlled to be low, and the repelling phenomenon to the BM hardened product hardly occurs, and even in the post-baking process. The white composition is less likely to flow into the pixel region. For this reason, the climbing rate compared to the film thickness of the flat pixel portion of the white composition formed on the BM portion is increased. That is, since the main PS height can be secured with the white composition, it is possible to obtain the necessary PS stacking height with a thinner colored pixel or with a photosensitive coloring composition having a smaller number of colors. Become. As will be described later, since a certain degree of linear relationship can be obtained between the content of the transparent extender pigment and the climbing rate, even if priority is given to the content of the colored pigment and the thickness of the colored pixel in favor of the hue, It is possible to control the height of the laminated PS by changing the content of the transparent extender pigment in the white composition.

  The transparent resin is a resin that disperses a black pigment, a color pigment, or a transparent extender pigment, and is a resin in which an unexposed portion can be dissolved and removed by an alkaline developer during development after pixel pattern exposure. Specifically, acrylic monomers such as alkyl acrylates, cyclic acrylates, cyclic methacrylates, hydroxyethyl ethyl acrylates, hydroxyethyl methacrylates, acrylic transparent resins composed of radical polymerizable monomers having ethylenically unsaturated groups, fluorene skeletons Epoxy acrylate transparent resin having a functional group or a polyfunctional epoxy resin in which a radical polymerizable monomer having an ethylenically unsaturated group is added can be used. However, it is not limited to the above resin.

As a photopolymerizable monomer, for example, the following monomers can be mixed or used alone. For example, monomers containing a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, Triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol di (meth) ) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate , (Meth) acrylic esters such as dipentaerythritol hexa (meth) acrylate, glycerol (meth) acrylate, or pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl Examples include (meth) acrylates, hexa (meth) acrylates of caprolactone adducts of dipentaerystol hexa (meth) acrylate, and melamine (meth) acrylates. It is preferable that a part of the polymerizable monomer is a polymerizable monomer containing a carboxyl group-containing polyfunctional monomer. For example, pentaerythritol or a derivative thereof may be used.

  As a photopolymerization initiator for generating an active species for initiating a polymerization reaction of a radical polymerizable monomer, tert-butylperoxy-iso-butarate, 2,5-dimethyl-2,5-bis (benzoyldioxy) hexane 1,4-bis [α- (tert-butyldioxy) -iso-propoxy] benzene, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butyldioxy) hexene hydroperoxide, α- (Iso-propylphenyl) -iso-propyl hydroperoxide, 2,5-bis (hydroperoxy) -2,5-dimethylhexane, tert-butyl hydroperoxide, 1,1-bis (tert-butyldioxy) -3,3 , 5-trimethylcyclohexane, butyl-4,4-bis (t-butyldioxy) valere -To, cyclohexanone peroxide, 2,2 ', 5,5'-tetra (tert-butylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (tert-butylperoxycarbonyl) benzophenone, 3,3 ' , 4,4′-tetra (tert-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (tert-hexylperoxycarbonyl) benzophenone, 3,3′-bis (tert-butylperoxycarbonyl)- Organic peroxides such as 4,4′-dicarboxybenzophenone, tert-butylperoxybenzoate, t-butyldiperoxyisophthalate, 9,10-anthraquinone, 1-chloroanthraquinone, 2- Quinones such as chloroanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone And benzoin derivatives such as benzoin methyl, benzoin ethyl ether, α-methylbenzoin, α-phenylbenzoin, and the like. Furthermore, as photopolymerization initiators that can be used in the present invention, Irgacure 651, 184, 1173, 907, 369, 379, 819, CGI 124, manufactured by Ciba Specialty Chemicals, TPO manufactured by BASF, Nippon Chemical In addition to Kayacure DTEX manufactured by Yakuhin Co., Ltd., or benzophenones such as 4,4′-diethylaminobenzophenone and 4,4′-dimethylaminobenzophenone, biimidazole compounds and triazine compounds can be exemplified.

  The photosensitive coloring composition contains an organic solvent in order to sufficiently disperse the pigment in the composition and facilitate application on the substrate. 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.

  As a coloring pigment contained in the photosensitive coloring composition according to the color filter substrate of the present invention, a commercially available organic pigment can be used. Moreover, a dye, a natural pigment, and an inorganic pigment can be used in combination according to the hue of the filter segment to be formed. As the organic pigment, those having high color developability and high heat resistance, particularly high heat decomposition resistance are preferably used. An organic pigment can be used individually by 1 type or in mixture of 2 or more types. Further, the organic pigment may be refined by salt milling, acid pasting or the like.

  Below, the specific example of the organic pigment which can be used for the photosensitive coloring composition which concerns on the color filter board | substrate of this invention is shown by a color index (CI) number. For the red pixel, for example, C.I. I. Pigment Red 7, 14, 41, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 81: 4, 146, 168, 177, 178, 179, 184, 185, Red pigments such as 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, and 279 can be used, and a yellow pigment and an orange pigment can also be used in combination.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180 181, 182, 187, 188, 193, 194, 199, 198, 213, 214 and the like. Examples of the orange pigment include C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.

  In the case where the red pixel contains one or more of diketopyrrolopyrrole red pigment and anthraquinone red pigment among these pigments, it is easy to obtain an arbitrary Rth (retardation value), which is preferable. . This is because the diketopyrrolopyrrole red pigment can be made positive or negative by devising the finer treatment, and its absolute value can be controlled to some extent. In addition, anthraquinone-based red pigments easily obtain Rth close to 0 regardless of the refinement treatment.

  The amount used is 10 to 90% by mass of the diketopyrrolopyrrole red pigment and 5 to 70% by mass of the anthraquinone red pigment based on the total mass of the pigment. From the viewpoint of contrast and the like. In particular, when focusing on contrast, it is more preferable that the diketopyrrolopyrrole red pigment is 25 to 75% by mass and the anthraquinone red pigment is 30 to 60% by mass.

  For example, C.I. I. Green pigments such as Pigment Green 7, 10, 36, 37, and 58 can be used, and a yellow pigment can be used in combination. As the yellow pigment, the same pigments as those used for the red pixel can be used.

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

When the blue pixel contains at least one of a metal phthalocyanine blue pigment and a dioxazine purple pigment among these pigments, it is easy to obtain a phase difference close to zero. The amount used is 40 to 100% by mass of the metal phthalocyanine blue pigment and 1 to 50% by mass of the dioxazine violet pigment based on the total mass of the pigment. It is preferable from the point. Further, it is more preferable that the metal phthalocyanine blue pigment is 50 to 98% by mass and the dioxazine violet pigment is 2 to 25% by mass. In the above, examples of the metal phthalocyanine blue pigment include C.I. I. Pigment Blue 15: 6, and dioxazine-based purple pigments include C.I. I. Pigment Violet 23 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  When dispersing the pigment in the resin, a dispersant such as a surfactant, a resin-type pigment dispersant, and a dye derivative can be appropriately used. Further, additives such as a chain transfer agent, a surfactant, and a silane coupling agent may be added for the purpose of improving applicability, improving sensitivity, and improving adhesion.

  The photosensitive coloring composition can be produced by mixing each component and finely dispersing it using various dispersing means such as a shaker, a desper, a three-roll mill, a two-roll mill, a sand mill, a kneader, and an attritor. . In addition, the photosensitive coloring composition may be mixed with a coarse particle of 5 μm or more, preferably a coarse particle of 1 μm or more, more preferably 0.5 μm or more by a means such as centrifugation, sintered filter, membrane filter, and the like. It is preferable to remove the dust.

  As the transparent substrate, a glass plate such as soda lime glass, low alkali borosilicate glass, non-alkali aluminoborosilicate glass or the like is used. As described above, a black matrix shading pattern is first formed on the transparent substrate in advance. Using the photosensitive white composition and the photosensitive coloring composition having the above-described composition prepared as an alkali development type colored resist material, spray coating, spin coating, slit coating, one color each on a BM-formed transparent substrate, It applies so that a dry film thickness may be set to 0.5-3 micrometers by application | coating methods, such as a roll coat. If necessary, the dried film is exposed to ultraviolet light through a mask having a predetermined pattern provided in contact with or non-contact with the film. Then, immerse it in an aqueous alkaline developer such as sodium carbonate or sodium hydroxide, or spray the developer with a spray to remove the uncured parts and form a desired pattern to form a filter segment for each color including white pixels And a laminated PS is formed. Furthermore, in order to accelerate | stimulate superposition | polymerization of a photosensitive white composition and a photosensitive coloring composition and to harden | cure, it heats (post-baking) as needed, respectively.

  In the color filter substrate of the present invention, a transparent protective layer may be further formed on the pixel and the laminated PS portion. In a liquid crystal that requires electric field driving in the thickness direction of the liquid crystal cell gap by a transparent electrode, such as a vertically aligned liquid crystal, a liquid crystal called OCB (Optically Compensated Birefringence), a ferroelectric liquid crystal, or a liquid crystal called ECB (Electrically Controlled Birefringence) And the process of forming a transparent conductive film can also be put after the process of forming laminated PS, and the process of forming a transparent protective layer. In this case, an insulating layer is formed on the transparent electrode on the laminated layer or at a site where the spacer of the counter substrate contacts. This insulating layer may be formed at the same time as the alignment regulating protrusion for the purpose of regulating liquid crystal alignment (alignment control) such as viewing angle and responsiveness improvement. For example, in the case of an IPS (lateral electric field) type liquid crystal display device which does not require the formation of a transparent conductive film as a color filter substrate, the insulating layer can be omitted.

  For example, in a VA liquid crystal display device in which liquid crystal is aligned vertically, a transparent electrode is formed on a black matrix, a white pixel, a colored pixel layer, and a laminated PS in advance, and a transparent resin is further used on the transparent electrode. Alternatively, a spacer or an alignment control protrusion may be formed.

  As a method for forming the transparent conductive film, vacuum deposition methods called vapor deposition, ion plating, and sputtering are generally used. For the transparent conductive film, a composite oxide of a metal oxide such as indium, tin, gallium, or zinc can be used.

  Specific examples of the present invention will be described below. In addition, this invention is not limited to a following example, unless the summary is exceeded. In Examples and Comparative Examples, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

  In order to clarify the effect of the present invention, a transparent extender pigment is contained on a 0.7 mm thick glass substrate on which a black matrix having a film thickness (height) of 2 μm is formed using a commercially available black photosensitive composition. A pseudo color filter having a laminated portion in which only white coloring compositions having different amounts were laminated was produced.

  First, preparation of acrylic resin solutions used in Examples and Comparative Examples 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).

[Preparation of acrylic resin solution]
A reaction vessel was charged with 370 parts of cyclohexanone, 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 the polymerization reaction. .
-20.0 parts of methacrylic acid-10.0 parts of methyl methacrylate-55.0 parts of n-butyl methacrylate-15.0 parts of 2-hydroxyethyl methacrylate-4.0 parts of 2,2'-azobisisobutyronitrile After completion of the reaction, the mixture was further reacted at 80 ° C. for 3 hours. 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 mass average molecular weight Mw of this acrylic resin was about 40000. After cooling to room temperature, about 2 g of the resin solution is sampled and heated and dried at 180 ° C. for 20 minutes, and the nonvolatile content is measured. Based on the measurement result, the previously synthesized acrylic resin solution has a nonvolatile content of 30%. Cyclohexanone was added to to prepare an acrylic resin solution.

[Preparation of photosensitive white composition]
The mixture of the composition (mass ratio) shown in Table 1 was stirred and mixed to be uniform, and then filtered through a 1 μm filter, and Comparative Example 1 containing no extender pigment was used, and transparent extender pigments having different contents were dispersed. The photosensitive white composition of Examples 1-5 was produced, respectively.

Specific contents of the materials constituting the compositions in Table 1 are shown below. Table 1 shows the mass of the solid content of each component when the mass of the acrylic resin is 100, and Pcon is a value obtained by calculating the solid content mass% of the transparent extender pigment (silicon dioxide: silica) contained in is there.
-Acrylic resin solution: previously prepared acrylic resin solution-Transparent extender pigment: "Organosilica sol: PMA-ST" (30% PGMac solution) manufactured by Nissan Chemical Co., Ltd.
Photopolymerizable monomer: “Aronix M402” manufactured by Toa Gosei Co., Ltd.
Photopolymerization initiator: “Irgacure 379” manufactured by Ciba Specialty Chemicals ・ Surfactant: “BYK330” 2% cyclohexanone solution manufactured by BYK Chemie ・ Organic solvent: EEP (ethyl-3-ethoxypropionate) / cyclohexanone [ White pixel, spacer formation]
A white pixel layer was formed using the resulting photosensitive white composition. A photosensitive white composition is spin-coated on a glass substrate on which a stripe-shaped resin black matrix having a thickness of 2 μm in advance and only a laminated portion is partially widened so that the finished film thickness becomes 2.0 μm. Applied. After drying at 90 ° C. for 5 minutes, it was irradiated with 300 mJ / cm ² of light from a high-pressure mercury lamp through a white pixel and a striped photomask for forming a laminated portion, and developed with an alkali developer for 60 seconds. A dot-shaped laminated portion having a diameter of 60 μm was obtained on a white pixel and a black matrix adjacent to the white pixel. Then, it hardened | cured at 230 degreeC for 30 minutes. As a result, as shown in FIG. 3, a pseudo color filter having a laminated portion having a stripe-shaped white pixel on a transparent substrate and a laminated PS pattern made of a white composition on a black matrix was obtained.

  The alkaline developer has the following composition.

Sodium carbonate 1.5% by mass
Sodium bicarbonate 0.5% by mass
Anionic surfactant (Kao Perillex NBL) 8.0% by mass
90.0% by mass of water
<Measurement of ride rate>
About the pseudo color filter produced using the photosensitive white composition of Examples 1-5 and Comparative Example 1, as shown in FIG. 3, the film thickness (a) of the white pixel and the dot-like lamination on the BM The film thickness (b) of the part was measured with a contact-type film thickness meter. Moreover, the boarding rate (b / a) was calculated. The results are shown in Table 2.

<Evaluation results>
From the results shown in Table 2, a relationship graph between the transparent extender pigment content (Pcon) and the run-up rate is shown in FIG. The main difference in composition between Examples 1 to 5 and Comparative Example 1 is the content of the transparent extender pigment, and as the amount of the transparent extender pigment increases, the tendency to increase the riding rate is seen, as shown in FIG. It was found that there is a substantially linear relationship between the content of the transparent extender pigment and the climbing rate.

  As a result of the above, in the color filter substrate having at least RGBW pixels using the photosensitive white composition of the present invention, the thickness of the white composition on the BM portion is compared with the thickness of the flat portion of the W pixel. Thus, it is possible to increase and control the climbing rate, and it is possible to obtain a necessary PS stacking height with a thinner colored pixel than in the past, or with a photosensitive colored composition having a smaller number of colors.

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Black matrix 3R ... Red pixel 3G ... Green pixel 3B ... Blue pixel 4 ... White pixel
5, 5W, 5R, 5G, 5B ... laminated PS 6 ... transparent electrode (ITO film)

Claims (1)

  At least one of a black matrix, a plurality of colored pixels and a white pixel on the substrate, and one or more of the photosensitive white composition constituting the white pixel and the photosensitive coloring composition constituting the colored pixel on the black matrix A color filter substrate having a laminated photospacer formed by laminating the above, wherein 5 to 40% by mass of a transparent extender pigment is contained in the total solid content of the photosensitive white composition Filter substrate.