JP2011039392A - Color filter substrate and method for producing the same - Google Patents

Abstract

When a black matrix, RGB colored pixels, transparent electrodes, and photo spacers are manufactured by a photolithography method, the required number of photomasks is six to seven, and the mask is increased as the mother glass becomes larger. There is a problem that the burden of cost increases.
On the substrate, at least the colored pixels with the side walls arranged in a mutually tapered manner, the transparent electrode layer, and the photospacer on the upper side at the position of the gap. , 8 is a color filter substrate characterized in that a black matrix 9 provided with 8 is laminated in this order.
[Selection] Figure 1

Description

  The present invention relates to a color filter substrate for coloring used in liquid crystal display devices widely used such as portable display terminals, personal computer monitors, and televisions.

  A liquid crystal display device is manufactured by sealing a substrate on which a TFT is formed and a substrate on which a color filter is formed so as to face each other in parallel and encapsulate the liquid crystal in a substrate gap of several μm. From mobile phones and personal computers to large-sized TVs, products of various sizes are manufactured, ranging from a small one having a diagonal of 5,6 cm to a large one having a size of about 130 cm.

  The color filter substrate that is indispensable for colorization of liquid crystal display devices is a substrate in which very fine colored pixels of red (R), green (G), and blue (B) are periodically arranged using photolithography technology. However, today, not only the substrate on which the colored pixels are formed, but also a member having a function other than coloring especially with an increase in size is provided as much as possible if it can be manufactured with a photosensitive resin. It has become. For example, photo spacers for holding the gap between the substrates, protrusions for controlling the alignment of the liquid crystal, formation of a protective film for reducing unevenness, and the like.

  Accordingly, in view of the fact that a black matrix has been formed on a color filter substrate, a black matrix, R, G, and B colored layers, protrusions for controlling the alignment of liquid crystals, and photo spacers are photolithography. It can be manufactured using technology.

  As for spacers, fine particle spacers made of organic materials or inorganic materials have been dispersed in the past, but photo spacers that can form protrusions of a predetermined shape at a predetermined location using a photosensitive resin give little display of foreign matters. Since the adverse effect is low, it is more advantageous than the fine particle spray type.

Japanese Patent Laid-Open No. 9-189904 JP 2002-258267 A JP 2003-121857 A

  However, if black matrix, R, G, and B colored pixels and photo spacers are manufactured by photolithography technology, the number of necessary photomasks is required from about 6 to 7 plates, and the mother glass becomes larger. There is a problem that the burden of the mask cost is increased.

  Further, in the conventional configuration in which the black matrix is formed on the glass substrate, there is a problem that the black matrix is not sufficiently adhered to the glass substrate, and the black matrix is peeled off when the panels are bonded together or in the panel reliability test. .

Furthermore, in the manufacturing method starting from the current black matrix, the shape of the black matrix is basically determined by the exposure and development conditions, but it is technically difficult to narrow the black matrix itself, so the light transmittance of the color filter substrate is difficult. There was a problem of low.
Therefore, the present invention provides means for simultaneously solving the above problems.

  The invention according to claim 1 for attaining the above-described object is that the side wall shape arranged on the substrate with a gap therebetween is a forward-tapered colored pixel, the transparent electrode layer, the position of the gap, The color filter substrate is characterized in that a black matrix having a photo spacer on top is laminated in this order.

  The invention according to claim 2 is the color filter substrate according to claim 1, wherein the black matrix including the photo spacer is formed of the same material at the same time.

  The invention according to claim 3 is the color filter substrate according to claim 1 or 2, wherein the photo spacer includes photo spacers having different heights.

  In the invention according to claim 4, on the substrate, at least a step of forming a colored pixel having a forward tapered shape in a side wall shape arranged with a gap therebetween, a step of forming a transparent electrode layer, and the position of the gap, And a step of forming a black matrix having a photo-spacer on the top using a multi-tone mask.

  According to the present invention, since the black matrix and the photo spacer are collectively formed, the input process is reduced and the manufacturing cost can be reduced.

  The black matrix is not formed on the glass substrate, but the transparent electrode layer for increasing the adhesion is interposed between the substrate and the black matrix, so that the adhesion of the black matrix to the substrate is improved. Therefore, there is no peeling of the black matrix.

  The shape below the side surface of the black matrix is not defined by the exposure and development conditions, and exhibits a reverse taper shape that is regulated by the forward taper shape of the base, so that obliquely incident light can be used without being blocked. In other words, the aperture ratio is increased by about 9 points.

  Since colored pixels do not run on the black matrix, the colored pixel surface becomes flat and does not adversely affect liquid crystal alignment.

  Furthermore, the use of a multi-tone photomask and the provision of photo spacers having different heights lead to improved panel reliability.

(a)-(d) is process drawing explaining the manufacturing process of the color filter substrate which becomes this invention.

  Hereinafter, an example of a manufacturing method and configuration of a color filter substrate according to the present invention will be described with reference to the drawings, but the present invention is not limited to the examples described herein. In the examples, “parts” and “%” mean “parts by weight” and “% by weight”, respectively.

First, material aspects such as the adjustment method of the acrylic resin solution and pigment dispersion used in the 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).

(Synthesis of acrylic resin solution)
370 parts of cyclohexane was placed in a reaction vessel, heated to 80 ° C. while injecting nitrogen gas into this vessel, and 20.0 parts of methacrylic acid, 10.0 parts of methyl methacrylate, 55.0 n-butyl methacrylate at the same temperature. A mixture of 15.0 parts of 2-hydroxyethyl methacrylate and 4.0 parts of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour to conduct a polymerization reaction.
After completion of the dropwise addition, the mixture was further reacted at 80 ° C. for 3 hours, then 1.0 part of azobisisobutyl dissolved in 50 parts of cyclohexane was added, and the reaction was further continued at 80 ° C. for 1 hour. A coalesced solution was obtained.

  After cooling to room temperature, 2 g of acrylic resin solution was sampled and heated and dried at 180 ° C. for 20 minutes to measure non-volatile components, and cyclohexanone was added to the previously synthesized acrylic resin solution so that the non-volatile content was 20% by weight. Then, an acrylic resin solution was prepared. The resulting acrylic resin had a weight average molecular weight of 40,000.

(Adjustment of pigment dispersion)
A mixture having the composition shown in Table 1 below was stirred and mixed, dispersed with a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered with a 5 μm filter to prepare a black pigment dispersion.

  Here, CB: carbon black (CI Pigment Black 7, “MA11” manufactured by Mitsubishi Chemical Co., Ltd.), pigment dispersant: “Solsperse 20000” manufactured by Nippon Lubrizeau, and organic solvent: cyclohexane.

  As the black matrix pigment, in addition to the carbon black, metal oxide components such as titanium oxide, titanium oxynitride, and iron tetroxide, pigments, and other known light shielding materials can be used. Furthermore, in order to adjust the color tone of the light shielding layer, a complementary color pigment may be mixed as necessary from the following pigments.

  The dispersion for coloring R, G, and B was prepared by appropriately using the following pigments.

  Examples of the red coloring dispersion 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 dispersion 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.

  Examples of the blue coloring dispersion 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. In addition, 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.

(Adjustment of photosensitive resin composition)
The mixture of the formulation shown in Table 2 including the previously prepared black pigment dispersion was stirred and mixed so as to be uniform, filtered through a 1 μm filter, and photosensitive resin of each BM, R, G, B A composition was obtained. In addition, Table 2 described the adjustment example of the black photosensitive resin composition, and the detail of the composition about R, G, B was abbreviate | omitted.

  Here, pigment dispersion: previously prepared product, acrylic resin: previously prepared product, monomer: dipentaerythritol hexaacrylate (“Aronix M-402” manufactured by Toagosei Co., Ltd.), organic solvent: cyclohexane, photopolymerization started Agent: α-aminoalkylphenone photopolymerization initiator 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (Ciba Specialty) “Irgacure 379” manufactured by Chemicals.

  In addition, as a resin that imparts photosensitivity, a reactive polymer such as an isocyanate group, an aldehyde group, or an epoxy group is added to a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group. It is possible to use a resin in which a photo-crosslinkable group such as a (meth) acryloyl group or a styryl group is introduced into the linear polymer by reacting the (meth) acrylic compound or cinnamic acid. Further, a linear polymer containing an acid anhydride such as a styrene-maleic anhydride copolymer or an α-olefin-maleic anhydride copolymer is converted into a (meth) acrylic compound having a hydroxyl group such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

  Examples of 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 (meta ) Acrylate, pentaerythritol tri (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) acrylate, bisphenol A diglycidyl ether di ( 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 ( Various acrylic esters and methacrylic esters such as (meth) acrylate and urethane acrylate, (meth) acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxy Examples include methyl (meth) acrylamide, N-vinylformamide, acrylonitrile and the like. These can be used alone or in admixture of two or more.

When curing by ultraviolet irradiation, a photopolymerization initiator or the like is added. Examples of the photopolymerization initiator include 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 ' Benzophenone compounds such as -methyldiphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4- Thioxanthone compounds such as diisopropylthioxanthone and 2,4-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 (trichloro) Methyl) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], O- (acetyl) -N- (1-phenyl-2-oxo-2- (4 ′ -Methoxy-naphthyl) ethylidene) oxime ester compounds such as hydroxylamine, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2,4,6-to Phosphine compounds such as methylbenzoyldiphenylphosphine oxide, quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone, borate compounds, carbazole compounds, imidazole compounds, titanocene compounds, etc. are used. . 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, a polyfunctional thiol that functions as a chain transfer agent can be contained. The polyfunctional thiol may be a compound having two or more thiol groups. For example, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene Glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, Pentaerythritol tetrakisthiopropionate, trimercaptopropionic acid tris (2-hydroxyethyl) isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercap -s- triazine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination. The amount of the polyfunctional thiol used is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the total solid content of the colored composition. If it is less than 0.1% by mass, the effect of adding a polyfunctional thiol is insufficient, and if it exceeds 30% by mass, the sensitivity is too high and the resolution is lowered.

  Moreover, an organic solvent can be contained as needed. 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.

  First, a red photosensitive resin was applied on the glass substrate 1 and dried to form an R (red) photosensitive resin layer. Then, the R colored pixel 2 was formed by pattern exposure using the photomask which used the site | part which forms R colored layer as an opening part (translucent part), and performing development and a post-baking process.

  Next, by repeating the same process for two colors (green and blue), a color filter substrate on which the G colored pixels 3 and the B colored pixels 4 were formed could be obtained (FIG. 1A). The coating thickness of each color can be set as appropriate, but considering the spectral transmittance and the like, the thickness after pre-baking is usually about 1 to 2 μm. 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 those obtained by adding an appropriate surfactant to them. In addition, as a coating method of the photosensitive resin resin layer, a spin coating method, a slit coating method, a coating method such as a bar coating method, an ink jet method, a printing method, or the like can be used.

  As the substrate 1 used in the present invention, commercially available inorganic glass substrates such as quartz glass, borosilicate glass and soda glass, plastic substrates such as PET, PES, and PC, or silicon oxide on these plastic substrates are used. In addition, an inorganic thin film such as aluminum oxide, silicon nitride, or silicon oxynitride formed on the surface can be used depending on the application.

  The colored pixels 2, 3, and 4 are preferably tapered as shown in FIG. The taper length of the colored pixels is determined by appropriately selecting from about 1 to 5 μm, the thickness is about 0.8 to 3.0 μm, and the width is about 20 to 40 μm. With the taper shape, as shown in FIG. 1D, the light cut by the lower surface of the black matrix 9 defined by this taper is reduced, and the light transmittance in the oblique direction is improved. For the black matrix 9, the line width may be different between the x direction and the y direction.

  Next, ITO was sputtered on the colored pixels 2, 3 and 4 to form the transparent electrode layer 5 (FIG. 1B). The material of the transparent electrode layer 5 is not particularly limited as long as it is a film that can achieve both the transmittance in the visible light region and the surface resistance value. In addition to indium tin oxide (ITO), indium zinc oxide (IZO) Aluminum zinc oxide (AZO) can be preferably used. The film thickness of the transparent electrode layer 5 is not particularly limited, but is about 1000 to 1500 mm.

  Next, the black photosensitive resin composition 6 was apply | coated on the transparent electrode layer 5 with the spin coater, and the solvent was dried and removed by performing reduced pressure drying (FIG.1 (c)).

Next, using a multitone photomask having a pattern of 20 μm with an interval of 150 μm, using a super high pressure mercury lamp lamp as a light source, pattern exposure was performed by irradiation at 200 mJ / cm ² , and 2.5% sodium carbonate Developed with an aqueous solution for 60 seconds and washed thoroughly with water. Further, it was dried and post-baked at 230 ° C. for 60 minutes to fix the pattern. The film thickness of the black matrix alone 9 (the black matrix on which the photo spacer is not mounted is not shown because it is a cross-sectional view) was 1.5 μm. The film thickness of the portion 7 where the photo spacer was thickly formed on the back of the black matrix 9 was 3.5 μm, and the film thickness of the sub-spacer 8 where the photo spacer was thinly formed was 2.7 μm (FIG. 1D).

  The multi-tone photomask used was formed with two portions having an intermediate transmittance in order to form two photo spacers having different heights in addition to a complete light shielding portion and a transmission portion. The ultraviolet transmittance of the part was 10% and 7%.

1. Substrate 2, colored pixel red (R)
3. Colored pixels Green (G)
4. Colored pixels Blue (B)
5, transparent electrode 6, black photosensitive resin 7, spacer 8, sub-spacer 9, black matrix

Claims (4)

On the substrate, at least
Colored pixels whose side wall shape is arranged with a gap between each other and has a forward taper shape,
Transparent electrode layer,
A color filter substrate, wherein a black matrix having a photo spacer on top is laminated in this order at a position of the gap.   The color filter substrate according to claim 1, wherein the black matrix including the photo spacer is formed of the same material at the same time.   The color filter substrate according to claim 1, wherein the photo spacer includes photo spacers having different heights. On the substrate, at least
A step of forming a colored pixel having a forward-tapered sidewall shape arranged with a gap between each other;
Forming a transparent electrode layer;
A method of manufacturing a color filter substrate, comprising: forming a black matrix having a photo spacer on the top using a multi-tone mask at a position of the gap.

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