JP4465757B2 - Manufacturing method of heat-resistant color filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a colored paste composition for baking for forming a colored layer containing an inorganic coloring pigment as a coloring material by baking.
The present invention also relates to a heat-resistant color filter applied to display devices such as field emission displays, fluorescent display devices, discharge display panels, and color liquid crystal displays, and solid-state imaging devices.
[0002]
[Prior art]
Conventionally, in a liquid crystal display, a color filter having a color characteristic of desired color light is used to display a color image, and these are organic pigments or organic dyes by a dyeing method, a pigment dispersion method, a printing method, or the like. A colored resin layer is used as a color filter. (See M.Tani, et al: "LCD Color Filters: Characteristics and Future Issues", SID 95 SEMINAR LECTURE (1995), etc.)
In addition, in cathode ray tube display devices (CRT), low-speed electron beam fluorescent display panels, discharge display panels, etc., it has been proposed to use color filters for reducing reflectance and controlling color characteristics when images are displayed. Yes. (See T.Ito, et al: "MicrofilterTM" Color CRT, SID 95 Digest, p.25 (1995) etc.)
As described above, in a display device, a solid-state imaging device, or the like, using a color filter for the purpose of reducing reflectance and controlling color characteristics is an effective means for improving color display image quality.
[0003]
By the way, in the case of a field emission display or a discharge display panel, a process of melting low-melting glass at a temperature of about 450 ° C. and sealing two glass substrates is used. For this reason, when color filters for liquid crystal displays are used as these color filters, the organic components constituting them cause reactions such as combustion and decomposition due to high heat during the production process, so that characteristics as color filters are obtained. I can't.
[0004]
As a solution to this problem, it has been proposed to use a color filter in which an inorganic coloring pigment is dispersed as a coloring material in a low-melting glass. (See Sakai et al .: “Ultra-low reflectance color display discharge panel (III)” Television Society Technical Report, ED993, IPD113-8 (1986-11), etc.)
As a method for forming the color filter pattern, a pixel paste on the glass substrate is colored by screen printing using a paste made of an inorganic color pigment, a low-melting glass powder, and an organic resin component that temporarily fixes them on the glass substrate. A pattern layer is formed. The printed color pattern layer is baked at about 600 ° C. to burn off organic resin components and the like, and the glass powder is melted to fix the inorganic color pigment to the glass substrate to obtain the color filter.
In this case, all the colored pattern layers are made of an inorganic material, and thus have durability against a high-temperature process related to the production.
[0005]
However, the low-melting glass powder is relatively expensive, and generally the powdery low-melting glass is not completely melted at a temperature of about 600 ° C. that the glass substrate can withstand. The low-melting glass cannot uniformly fill the voids formed by the burning and cannot exhibit sufficient transparency.
That is, the colored pattern layer is not sufficiently fixed to prevent the peeling of the colored pattern layer when handling the substrate, and the incident light is scattered due to the difference in refractive index between the inorganic colored pigment and air. There is a problem that the colored pattern layer is whitened and the color characteristics are deteriorated at the same time that it cannot be sufficiently suppressed.
[0006]
[Problems to be solved by the invention]
The present invention has been made in order to solve such problems, and it is an object of the present invention to provide a colored paste composition having sufficient fixing strength to a transparent substrate, a field emission display, and a fluorescent display device. Another object of the present invention is to provide a heat-resistant color filter having excellent color characteristics suitable for display devices such as discharge display panels and color liquid crystal displays and solid-state imaging devices.
[0007]
[Means for Solving the Problems]
1st invention of this invention is the coloring paste composition for baking which has (A) inorganic or organic phosphorus compound, (B) inorganic coloring pigment, and (C) resin as a main component.
[0008]
According to a second aspect of the present invention, there is provided a heat-resistant color filter characterized in that a colored pattern layer formed on a transparent substrate contains a phosphate glass and an inorganic colored pigment.
[0009]
A third aspect of the present invention is the heat resistant color filter according to claim 2, wherein the phosphate glass is contained in an amount of 0.1 to 50% by weight based on the inorganic color pigment.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
As the (A) inorganic or organic phosphorus compound in the present invention, phosphoric acid such as orthophosphoric acid, metaphosphoric acid and pyrophosphoric acid can be used. In addition to phosphoric acid, various phosphates, phosphate esters and the like can also be suitably used. Regarding the blending amount of (A), the phosphate glass produced by firing is 0.1% to 50% by weight, preferably 1% to 30% by weight, based on the inorganic color pigment. Decide the amount.
[0011]
The inorganic color pigment (B) in the present invention serves as a coloring material. For this, an inorganic compound resistant to heat can be suitably used. For example, inorganic oxides having various colors called red iron oxide, cobalt green, cobalt blue, molybdate orange, titanium yellow, and cobalt purple can be used. Moreover, it is also possible to adjust the color as appropriate by mixing a plurality of these.
[0012]
The (C) resin in the present invention is necessary for temporarily fixing the color material on the substrate. For example, vinyl acetate resin, ethyl cellulose, vinyl butyral resin, methyl methacrylate resin, nitrocellulose, polyvinyl alcohol, vinyl formal resin, shellac, rosin, polyethylene, acrylic resin, vinyl chloride resin, polyester resin, urea resin, phthalate An acid resin, a phenol resin, polystyrene, a vinylidene chloride resin, or the like can be used, and it can be suitably used alone or as a mixture of two or more. However, in the heat resistant color filter, it is not preferable that carbon in the organic component remains in a carbonaceous state at the time of firing because it affects the color characteristics. Therefore, the organic component may be a compound having a short carbon chain. desirable. This resin is desirably 1 to 500 parts by weight, and more preferably 5 to 300 parts by weight with respect to 100 parts by weight of the inorganic coloring pigment (B) which is a color material.
[0013]
Moreover, a solvent component can be suitably mix | blended as needed. The solvent can be arbitrarily used depending on the compatibility with the resin component and the like, the affinity with the coloring material, the pattern formation method, and the like. Cyclohexanone, hexane, toluene, 2- (2-ethoxyethoxy) ethanol Etc. can be used suitably. A compounding quantity is 5-400 weight part with respect to 100 weight part of resin components, More preferably, it is 10-200 weight part.
[0014]
Furthermore, silicic acid such as orthosilicic acid, mesosilicic acid, mesodisilicic acid, mesotrisilicic acid, mesotetrasilicic acid, etc. can be used in order to secure the adhesion to the glass substrate used for the transparent substrate as necessary. . In addition to silicic acid, various silicas, silicates, polysiloxanes, alkoxysilanes, and the like can be suitably used. The amount is 1 to 100 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the inorganic or organic phosphorus compound (A).
These materials are mixed into a colored paste by a known dispersion mixing method such as a disper mixer or a sand mill.
[0015]
Next, the heat-resistant color filter according to claims 2 and 3, which is the second and third inventions of the present invention, will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a heat-resistant color filter according to claim 2, which is an embodiment thereof. As shown in FIG. 1, the heat-resistant color filter 1 includes a blue color material 5, a green color material 6, and a red color material 7 dispersed in a phosphate glass 4 on a transparent substrate 2. It is formed in a pixel shape such as a stripe shape or a mosaic shape. As the transparent substrate 2, an arbitrary substrate having high transparency and excellent in various properties such as heat resistance and weather resistance can be used, but generally a glass substrate is used.
The phosphate glass 4 can be obtained by reacting the firing colored paste composition according to claim 1 at 400 ° C. or higher.
[0016]
Here, the phosphate glass 4 contained in the colored pattern layer 3 formed on the transparent substrate 2 is preferably contained in an amount of 0.1 wt% to 50 wt% with respect to each of the color materials 5 to 7. More preferably, it is 1 to 30% by weight.
When the phosphate glass is less than 0.1% by weight with respect to the color material, the color pattern layer made of the color material is not sufficiently fixed, sufficient strength cannot be obtained, and the color material formed by the burned-out organic component The voids between them are not sufficiently filled, and scattering of incident light cannot be suppressed. On the other hand, if it exceeds 50% by weight, the pores between the coloring materials when organic components are burned out are sufficiently filled, and the strength due to fixation is imparted. However, the increase in the layer thickness tends to cause cracks and rough surfaces. At the same time, the color characteristics are degraded.
[0017]
Next, as a method of forming the colored pattern layer 3, an inorganic coloring pigment as a coloring material is dispersed in a resin by a known dispersion method such as a disper mixer or a sand mill, and an inorganic or organic phosphorus compound is dispersed during or after the dispersion. Mix. A sufficiently mixed colored paste can be patterned on the transparent substrate 2 and baked at a high temperature exceeding 400 ° C. to form the paste.
[0018]
The patterning method is arbitrary, but in the production stage, the printing method, the photolithography method, the electrophotographic method, the electrodeposition method, the transfer method, etc. are generally used, and any method can be used. Here, a case where an alkali development method which is one method of the photolithography method is used will be described. In the alkali development method, a photosensitive monomer, a photopolymerization initiator, or the like is suitably blended with a resin having an acidic functional group such as a carboxyl group, and a pattern can be formed using photopolymerization and photocrosslinking reaction.
[0019]
Examples of photosensitive monomers include N-vinylpyrrolidone, acrylic acid esters such as ethyl acrylate and propyl acrylate, methacrylic acid esters such as ethyl methacrylate and propyl methacrylate, tetrahydrofurfuryl methacrylate, and derivatives such as caprolactone modified products thereof, styrene. , Α-methylstyrene, acrylic acid, and the like, and mixtures thereof. The amount used is desirably 1 to 100 parts by weight, more preferably 5 to 80 parts by weight based on 100 parts by weight of the resin component.
[0020]
Examples of photopolymerization initiators include benzoin such as benzoin, benzoin methyl ether, and benzoin ethyl ether and alkyl ethers thereof; acetophenones such as acetophenone and 2,2-dimethoxy-2-phenylacetophenone; methylanthraquinone, 2-ethylanthraquinone, and the like Anthraquinones; thioxanthones such as thioxanthone and 2,4-diethylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone and 4,4-bismethylaminobenzophenone, azo compounds, triazine compounds, etc. Can be suitably used alone or as a mixture of two or more. The amount used is desirably 1 to 50 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of the photosensitive monomer.
[0021]
Moreover, a solvent component can be suitably mix | blended as needed. The solvent can be arbitrarily used depending on the compatibility with the resin component and the like, the affinity with the coloring material, the pattern formation method, and the like, and the blending amount is 5 to 400 weights with respect to 100 parts by weight of the resin component. Parts, more preferably 10 to 200 parts by weight.
Furthermore, various compounding components can be suitably blended in addition to known general additives and fillers as necessary. For example, wetting agents and dispersants that improve wettability to resin components and solvents of colorants and dispersion stability, leveling agents that give smoothness when colored paste is coated, and adjust viscosity of colored paste A rheology control agent or the like can be suitably blended. The blending amount of the wetting agent and the dispersing agent is desirably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the color material. The blending amount of the leveling agent, the rheology control agent and the like is desirably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the resin component.
[0022]
Here, the above-mentioned colored paste composition mixed with the photosensitive monomer and the photopolymerization initiator is screen-printed on a transparent substrate. And after carrying out exposure hardening using a photomask, an unexposed part is removed with an alkali developing solution, and it is made to dry, and a colored pattern layer is formed. The thickness of the colored pattern layer patterned on the substrate is preferably 0.5 to 30 μm. More preferably, it is 1-20 micrometers.
[0023]
Each color pattern formed as described above is baked at a high temperature exceeding 400 ° C. in the air or in an inert gas atmosphere to obtain a color filter.
The thickness of the colored pattern layer after firing is preferably 0.1 to 20 μm, more preferably 1 to 10 μm.
[0024]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The “parts” and “%” are based on weight unless otherwise specified.
<Example 1>
First, 50 parts of butyl methacrylate, 20 parts of methyl methacrylate and 30 parts of methyl acrylate are copolymerized using 2- (2-ethoxyethoxy) ethanol as a solvent to produce an acrylic resin. The acrylic resin solution was adjusted so that the solvent was 60 parts relative to 40 parts of this acrylic resin. Then, with respect to 20 parts of this acrylic resin solution, 3.1 parts of orthophosphoric acid as a phosphorus compound, 32 parts of a blue pigment (manufactured by Asahi Kasei Kogyo Co., Ltd .: Super Blue CR2) as a coloring material, and 2- (2-ethoxyethoxy as a solvent) ) After 43 parts of ethanol and 1.5 parts of orthosilicic acid as a silicon compound were pre-dispersed with a disper, they were dispersed with a bead mill (Eiger Mill minimill moter manufactured by Eiger Japan) for 1 hour.
[0025]
Next, 2 parts of dipentaerythritol and 2 parts of hexaacrylate as a photosensitive monomer and 1 part of a photopolymerization initiator piperonyltrichloromethyl S-triazine were mixed with a disper.
This blue paste was screen printed on a transparent glass substrate using a 325 mesh, 80 μm thick stainless steel screen plate, allowed to stand at room temperature for 10 minutes to smooth the film surface, and then dried at 70 ° C. for 20 minutes. It was.
[0026]
Next, a photomask having a light-shielding film in which a stripe pattern of 200 mm in length and 210 μm in width was repeatedly formed at a pitch of 450 μm was brought into close contact, and contact exposure was performed with an ultrahigh pressure mercury lamp at an exposure amount of 150 mJ / cm ² . After the exposure, spray development was performed for 90 seconds at an ejection pressure of 1 kg / cm ² with an alkali developer at a temperature of 20 ° C. to remove the unexposed areas and expose the glass substrate. The substrate after the development treatment was dried and then heated at 230 ° C. for 1 hour to carry out a hardening treatment. The thickness of the blue pattern layer after hardening was 4.1 μm.
[0027]
A green paste (manufactured by Dainichi Seika Kogyo Co., Ltd .: TM GREEN # 3340) was used as a coloring material on the substrate on which the blue pattern layer was formed, and then a green paste was prepared with the same composition as described above, and then applied under the same conditions as described above. did.
Next, contact exposure was performed using the same photomask as described above under the condition of an exposure amount of 400 mJ / cm ² . After the exposure, spray development was performed for 60 seconds with an alkali developer at a temperature of 20 ° C. under an ejection pressure of 1 kg / cm ² to remove unexposed portions and expose the glass substrate. The substrate after the development treatment was dried and then heated at 230 ° C. for 1 hour to carry out a hardening treatment.
The thickness of the green pattern layer after hardening was 5.2 μm.
[0028]
In the same manner as in the formation of the blue and green pattern layers, a red pigment was prepared as a color material (Daiichi Seika Kogyo Co., Ltd .: TOR), and a red paste was prepared to form a pattern. The film thickness of the red pattern at this time was 2.3 μm.
And after heating this board | substrate in air | atmosphere with the temperature increase rate of 4 degree-C / min and baking for 60 minutes at the temperature of 440 degreeC, it further heats continuously to 600 degreeC and after baking for 45 minutes at the temperature of 600 degreeC When the substrate was cooled at a temperature drop rate of 4 ° C. per minute, the organic resin component of each color pattern layer was burned and removed, and the contained phosphoric acid and silicic acid reacted to form SiO ₂ · P ₂ O ₅ , A pattern made of a color material of each color was fixed to the substrate and the pattern was covered (see FIG. 1). SiO ₂ · P ₂ O ₅ was confirmed by an electron beam analyzer and X-ray diffraction.
The film thicknesses of the blue, green, and red pattern layers after firing were 3.7 μm, 4.7 μm, and 2.0 μm, respectively.
[0029]
<Example 2>
Next, 8.5 parts of tributyl phosphate was used to prepare a blue paste with the same composition as in Example 1, and a pattern was formed under the same conditions as described above, and a blue pattern layer having a thickness of 4.3 μm after the heat hardening treatment was formed. Formed.
Next, green and red pattern layers were sequentially formed on the substrate in the same manner as the blue pattern layer. The film thickness of the green pattern after film hardening was 5.7 μm, and the film thickness of the red pattern was 2.7 μm.
This substrate was heated in the air atmosphere at a temperature rising rate of 4 ° C. per minute in the same manner as described above, continuously heated to 600 ° C., baked at a temperature of 600 ° C. for 45 minutes, and then baked at a temperature of 440 ° C. for 60 minutes. Thereafter, the substrate is cooled at a temperature drop rate of 4 ° C. per minute, the organic resin component of each color pattern is burned and removed, SiO ₂ · P ₂ O ₅ is formed, and the pattern made of the color material is fixed to the substrate. The pattern was coated (see FIG. 1). At this time, SiO ₂ · P ₂ O ₅ was confirmed by an electron beam analyzer and X-ray diffraction.
The film thicknesses of the blue, green, and red pattern layers after firing were 3.9 μm, 5.1 μm, and 2.2 μm, respectively.
[0030]
<Comparative Example 1>
In order to compare the color characteristics of the heat-resistant color filters prepared in Example 1 and Example 2, Example 1 and Example were used as color materials in a low melting glass powder (manufactured by Nippon Electric Glass Co., Ltd .: GA-9). Similar heat-resistant color filters were prepared with each color paste having a composition using the same inorganic pigment as in Example 2.
The film thicknesses of the blue, green and red pattern layers after patterning were 4.4 μm, 5.3 μm and 2.1 μm.
The film thickness after firing was 3.6 μm, 4.8 μm, and 1.7 μm, respectively.
[0031]
<Evaluation>
The transmission spectrum of each color pattern of Example 1, Example 2 and Comparative Example 1 was measured with a spectrophotometer (Spectrophotometer manufactured by Shimadzu Corporation, UV3100), and the results are shown in FIGS. 2, 3 and 4, respectively. Show.
2, 3, and 4, the heat resistant color filters obtained in Example 1 and Example 2 compare the difference between the maximum value and the minimum value of the transmittance curve in the visible range for any color. It was larger than Example 1, and it was found that high contrast was obtained and color characteristics were improved.
The color filters of Examples 1 and 2 did not peel off the colored pattern layer even during the handling.
[0032]
【The invention's effect】
If the colored paste composition for baking of the present invention is used for the colored pattern layer of the color filter, the colored pattern layer is fixed on the transparent substrate with sufficient strength, and the color formed by the organic component in which the phosphate glass is burned out. By filling the holes between the materials and covering the pattern, it is possible to obtain a heat-resistant color filter with suppressed scattering of incident light and improved color characteristics.
[0033]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a heat-resistant color filter showing an embodiment of the present invention. FIG. 2 is a spectral transmittance curve of a heat-resistant color filter manufactured according to Example 1. FIG. Spectral transmittance curve of heat-resistant color filter [Fig. 4] Spectral transmittance curve of heat-resistant color filter prepared in Comparative Example 1 [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Heat resistant color filter 2 ... Transparent substrate 3 ... Colored pattern layer 4 ... Phosphate glass 5 ... Blue color material 6 ... Green color material 7 ... Red color material

Claims (3)

In the manufacturing method of the heat resistant color filter,
A layer of (A) an inorganic or organic phosphorous compound, (B) an inorganic coloring pigment, (C) a resin, and (D) a colored paste composition for firing mainly composed of orthosilicic acid is formed on a transparent substrate by screen printing. Process,
Forming each color pattern on the layer of the colored paste composition for baking using a photolithography method;
And heating each of the color patterns at a high temperature of 400 ° C. or higher to form SiO ₂ · P ₂ O ₅ to fix the color patterns and form a colored pattern layer. Method for producing a color filter. In the heating step, the transparent substrate is heated in the air atmosphere at a temperature rising rate of 4 ° C./min and baked at a temperature of 440 ° C. for 60 minutes, and then further heated to 600 ° C. The method for producing a heat-resistant color filter according to claim 1 , wherein the substrate is cooled at a temperature falling rate of 4 ° C. per minute after baking at a temperature for 45 minutes. 3. The method for producing a heat-resistant color filter according to claim 1, wherein the colored pattern layer has a thickness of 1 to 10 μm after the heating step.

Images