JPH07151911A - Color filter and its production - Google Patents

Abstract

PURPOSE:To uniformly stick a color filter to another electrode substrate or a polarizing plate by forming a pattern of a color ink coating film by using a printing ink on a substrate and polishing the surface of the coating film with a suspension liquid. CONSTITUTION:The color filter is produced by a printing method by forming a pattern of a color ink coating film 12 on a substrate 11 with using a printing ink. The surface of the coating film 12 is polished with a suspension liquid prepared by dissolving fine particles such as alumina having 0.06-1mum particle size in a liquid such as water. Thus, the surface of the color ink coating film 12 roughened with a lapping film is processed into an extremely smooth surface, and a color filter having improved transparency is obtd. By this method, an irregular rough state of the surface of the color ink coating film formed on a glass substrate is smoothed and projections due to dust or the like are scraped. Therefore, when the color filter is to be stuck to another electrode substrate or a polarizing plate, uniform sticking can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter used for a photodetection component of a liquid crystal display or other precision electronic device by forming a colored ink film on a substrate such as glass by a printing method, and a method for producing the same. .

[0002]

2. Description of the Related Art A colored filter having a desired pattern of a colored ink film of three primary colors of blue (B), green (G) and red (R) used for manufacturing a liquid crystal color display panel or the like has a colored ink film surface. If it is not smoothed, when assembling as a display, when laminated with another substrate such as thin plate glass for electrode formation or polarizing plate glass, voids and bubbles are created on the inner surface of the overlay, and the glass is parallel and even. It becomes impossible to attach it easily. In addition, ITO is formed on the colored ink film formed on the substrate.
When a film is formed by sputtering, etc., if the surface of the colored ink film has irregularities and the film thickness is uneven, the sputtered film may become insufficient at the thick part of the film, or the sputtered film may be formed. However, there is a possibility that wire breakage may occur, and thus the processing after manufacturing the color filter is likely to be hindered. In addition, the light diffusion phenomenon due to fine irregularities on the surface of the colored ink coating impairs the transparency and causes other optical loss.

Therefore, in the color filter manufactured by forming a colored ink film on a glass substrate by a printing method and a manufacturing method thereof, in order to solve the above-mentioned inconvenience, conventionally, the smoothness and the film thickness of the colored ink film surface have hitherto been known. In order to obtain the evenness of the film, a smooth roll heated to a predetermined temperature is applied to the surface of the colored ink film, and the surface of the film heated to near the glass transition point of the ink is rolled to obtain the smoothness of the film surface. Was doing.

However, the thickness of the color ink coating of this color filter is at most about 3 μm, and it is necessary to apply pressure evenly to smooth the color ink coating on the roll, and the color ink coating on the roll by heat is applied. The fusing affects the production yield of the color filter.

A method for producing a color filter having a flat film surface is disclosed in, for example, Japanese Patent Application No. 59-123439.
There is a method of manufacturing a liquid crystal color display element as disclosed in Japanese Patent Publication No. However, in this method, the surface of the colored ink film is polished with a wrapping film and then coated to obtain smoothness of the final film surface.

[0006]

However, polishing with a wrapping film makes the colored ink film flat,
Microscopically, since the coating is roughened and light is scattered, when this color filter is used as a display, there are problems such as deterioration of resolution, which is not preferable for optical characteristics.

In particular, when the ink used for printing formed on a substrate such as glass in the present invention mainly comprises a varnish containing a volatile solvent, the ink solvent contained in the ink rapidly increases with time after printing. The hardness of the ink increases as it evaporates. As a means for smoothing a film having high hardness, lapping with a wrapping film gives a diameter of 10
The protrusions with a height of 1 μm or more and 1 μm to 30 μm are removed. As a characteristic of polishing with a wrapping film, only the convex portions are scraped off without touching the concave portions.

Therefore, a surface having a uniform film thickness can be obtained by polishing to the position of the minimum film thickness. However, polishing with a wrapping film does not give a glossy surface because it makes the coating surface rough.

[0009]

In order to smooth the final coating surface, that is, the surface, a suspension of fine particles of alumina or the like having a particle diameter of 0.06 μm to 1 μm in a liquid such as water is used. The colored ink film roughened by the wrapping film is made extremely smooth to obtain a color filter with improved transparency.

Particularly, this polishing has a great effect after the polishing with the lapping film.

Further, polishing with a suspension in which fine particles are mixed with a liquid has the effect of making the rough surface of the coating film by lapping polishing a glossy and smooth surface. Polishing with a wrapping film is generally performed using a soft cloth for polishing which is impregnated with suspension.

Therefore, the ink film is smoothed with a soft cloth and small abrasive grains (0.06 μm to 0.3 μm) are used.
This makes it possible to finish the ink film on a glossy surface.

[0013]

After the colored ink film is formed on the pattern by using the printing ink, the surface of the film is polished with the material of fine particles such as alumina, so that the unevenness peculiar to the printing method, In addition, the method for producing a color filter is characterized in that the film surface is smoothed and made transparent by removing extremely minute irregularities that scatter light from the viewpoint of an optical system.

[0014]

EXAMPLES In more detail, FIGS. 2 (a) and 2 (b) show a color ink after printing on a glass substrate (11) by an intaglio offset printing method equipped with a pressure transfer blanket. The cross-section of the coating (12) in the rolling direction of the transfer blanket (hereinafter referred to as the vertical section) and the cross section perpendicular to the rolling direction of the transfer blanket (hereinafter referred to as the horizontal section) are formed.

In FIG. 2, the colored ink coating (12) is moved onto the substrate (11) by rotating the pressure transfer blanket from the right to the left in the drawing while rotating it.
It is printed for each color. In the vertical cross-sectional view of FIG. 2A, in the pixels of each color, the blanket causes a swelling of the coloring ink on the left side of the coloring ink film (2) on the side where printing is finally finished, and the second and third colors are formed. It shows that the thickness of the boundary of each color becomes the minimum when the printing is repeated.

Further, in the transverse sectional view of FIG. 2B, the surface of the colored ink film is formed into an arc shape in the pixel of each color, and when the second and third colors are overprinted, the film thickness at the boundary of each color is minimum. Indicates that the film thickness is maximum in the central portion of each color. After printing the colored ink film on the substrate in three colors, red, green, and blue, the swelling part in each color pixel is removed by using a lapping film to which fine particles such as alumina are adhered. To form a uniform rough surface.

In this state, the transparency required for the color filter is lost. However, after that, fine particles of alumina, zirconia, diamond or the like are mixed with water or a solution containing alcohol as a main component, and the rough coating surface is polished with an abrasive that has been diffused. Then, the rough surface by lapping becomes an extremely smooth surface, the optical characteristics are improved, and the transparency is improved.

Further, the film surface having a film thickness difference of 2 μm before polishing has a film pressure difference of 0.1 μm or less after polishing.

Example 1 An intaglio offset printing machine was used to form a film of 3 to 5 μm on a glass substrate (11) in accordance with an intaglio cell pattern, using a coloring ink mainly composed of a pigment and a solvent type epoxy resin varnish. When a thick colored ink film (12) was formed, this colored ink film (12) swelled at the trailing end in the printing direction (Max thin thickness 5 μ
m).

After that, it is dried and cured, and the colored ink film is polished by using an alumina lapping film having an abrasive grain of 0.1 μm. Then, a urethane polishing cloth is attached to a single-side polishing machine, and an average particle diameter is used as a polishing material. It was re-polished using a 0.06 μm alumina suspension. Before polishing, the difference in thickness of the colored ink coating (12), which was 2 μm, was within 0.2 μm, and an extremely smooth and glossy surface was obtained.

[0021]

INDUSTRIAL APPLICABILITY The present invention makes the unevenness generated on the surface of the colored ink film formed on the glass substrate in the color filter manufactured by the printing method extremely smooth,
In addition, since projections of several tens of μm due to dust or the like can be scraped off, it is possible to perform a uniform sticking process when sticking a color filter to another electrode substrate or polarizing plate, and to sputter a colored ink film. In such a case, the smoothness of the colored ink film provides a proper vapor deposition film, and the transparency of the color filter and the color filter B. G. The spectral transmittance of each R color is improved, and proper color balance can be obtained even in a liquid crystal color display or the like.

Further, since the polishing is a principle of scraping off, it is possible to make the colored ink film thinner. In the liquid crystal color display, there is a problem of a viewing angle peculiar to the liquid crystal, and thinning of the color filter is required.

As described above, the polishing has a remarkable effect in the color filter by the printing method and the manufacturing method thereof.

[0024]

[Brief description of drawings]

FIG. 1A is a cross-sectional view in the printing direction of the same colored ink film that has been polished, and FIG. 1B is a cross-sectional view perpendicular to the printing direction.

FIG. 2A is a cross-sectional view of a colored ink coating in the printing direction, and FIG. 2B is a cross-sectional view perpendicular to the printing direction.

[Explanation of symbols]

 (R) ... Red ink film (G) ... Green ink film (B) ... Blue ink film (11) ... Substrate (12) ... Colored ink film

Claims (7)

[Claims] 1. A color filter of a printing system in which a colored ink film is formed in a pattern on a substrate by using a printing ink, wherein the film surface of the colored ink film is a suspension polishing surface. . 2. The color filter according to claim 1, wherein the printing method is screen printing or intaglio offset printing method. 3. The color filter according to claim 1, wherein the printing ink is mainly composed of a pigment and a solvent type epoxy resin varnish. 4. A suspension is used for final polishing of the coating surface of the colored ink film of a printing type color filter in which a colored ink film is formed in a pattern on a substrate using a printing ink. Color filter manufacturing method. 5. The method for producing a color filter according to claim 4, wherein the printing method is screen printing or intaglio offset printing method. 6. The method for producing a color filter according to claim 4, wherein the printing ink mainly comprises a pigment and a solvent-type epoxy resin varnish. 7. A suspension according to claim 4, wherein fine particles such as alumina are mixed with water or alcohol.
Item 7. The method for producing a color filter according to any one of Items 5, 5 and 6.