JP3254798B2 - Reproduction method of color filter light shielding film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reproducing a light-shielding film of a color filter suitable for a color liquid crystal display device such as a color liquid crystal television and a color liquid crystal display for a computer.

[0002]

2. Description of the Related Art In a color filter, a light-shielding film is provided adjacent to a gap between R, G, and B pixels on a transparent substrate and an outer side of a colored pattern portion composed of R, G, and B pixels. In addition, it is preferable to form a frame light-shielding film. The light-shielding film is provided to improve display quality and color contrast by preventing light leakage from the color filter pixel gap, and the frame light-shielding film is provided from a pixel end when the cell is assembled. It is provided to prevent light leakage and provide a clear image (for example, Japanese Patent Application Laid-Open No. 2-193184).

A light-shielding film of a color filter is usually formed by etching a metal chromium deposition film or a sputtering film. At this time, it is essential to form the chromium film uniformly and free from defects such as pinholes, and the pattern is formed through steps such as resist coating, exposure, development, baking, etching, and resist peeling.
However, such a method using metal chromium is not preferable because it is expensive, reflects light, and deteriorates image quality.

On the other hand, there have been proposed a printing method using an ink or a paste obtained by coloring a photosensitive resist material with a black pigment, a coating method using a spinner, a roll coater, or the like, and a method of patterning by mask exposure. Since this method is inexpensive and does not reflect light as compared with the metal chromium method, development of a resin light-shielding film exclusively using a colored paste or the like has been actively performed recently.

[0005]

When such a resin light-shielding film is formed, a method (preparing method) in which a resin light-shielding film is formed on a substrate before forming an R, G, B pattern, and an R, G, B pattern are formed. Method of forming a light-shielding film after forming a mask (post-installation method)
There is. In the case of the pre-applying method, since the light-shielding film is formed first, even if a defective product occurs during the formation of the light-shielding film, it is not a major problem in terms of cost. However, in the case of the post-attachment method, since the light-shielding film is formed after forming the R, G, and B products,
If defective products (projections due to foreign matter in the light-shielding film, white pins (white spots in the light-shielding film), black pins (part of the light-shielding film remaining on or adhered to the pixels) during the formation of the light-shielding film, etc.) It greatly affects process yield and overall cost. Various studies have been made in the past to prevent the generation of a light-shielding film of a defective product, but at present, it has not yet been completely prevented.

Therefore, the present inventors have changed the viewpoint from the prior art and made intensive studies on how to increase the process yield even when a defective product occurs.

That is, an object of the present invention is to provide a method for increasing the process yield and reducing the overall cost even if a defective product occurs during the formation of the light-shielding film of the color filter.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
After forming pixels of a plurality of colors on the transparent substrate, the color filter produced by forming a light-shielding film in the gap between each pixel is immersed in a stripping solution to remove only the light-shielding film, and again, This is achieved by a color filter light-shielding film reproducing method, wherein a light-shielding film is formed in a gap between pixels.

Hereinafter, the present invention will be described in detail.

The color filter used in the color filter light-shielding film reproducing method of the present invention is manufactured by forming pixels of a plurality of colors on a transparent substrate and then forming a light-shielding film in a gap between the pixels. And a colored pattern composed of pixels of a plurality of colors and a light-shielding film at a predetermined position on the center side of the transparent substrate.

The transparent substrate used for the color filter is not particularly limited, but glass or transparent plastic is preferably used.

Each pixel is usually red (R), green (G), and blue (B), and the shape of each pixel is not particularly limited, but is generally a stripe shape, a mosaic shape, or the like. . Further, between each pixel, usually, 10 to 2
A space of about 0 μm is provided, and a light-shielding film is formed in this space. Examples of the material of the pixel include a material in which a coloring pigment and other additives are mixed and dispersed in a polymer such as a polyimide polymer, an acrylic polymer, or a polyvinyl alcohol polymer.

As a method for forming the light-shielding film, any known method can be used, and examples thereof include a photosensitive paste method, a non-photosensitive paste method (photoresist method), a printing method, and an electrodeposition method.

A method for forming a light shielding film by a photosensitive paste method will be described. In this case, a photosensitive paste containing a coloring component, a photosensitive component, and a solvent as main components is applied on a transparent substrate on which pixels are formed in advance, and dried, exposed, and developed to shield light from the gaps between the pixels. Form a film. The method of exposure includes a method of exposing from the front side of the transparent substrate and a method of exposing from the back side. When exposure is performed from the front side, a mask is required, and a position shift can be covered by overlapping a part of the light shielding film with an adjacent pixel pattern. On the other hand, in the case of exposure from the back side, since each pixel pattern serves as a mask, alignment is unnecessary and a light-shielding film with high dimensional accuracy can be formed. Examples of the material of the light-shielding film include a mixture of an acrylic polymer, a polyimide polymer, a black pigment as a black coloring component, and other additives.

[0015] The color filter obtained in this way goes through the inspection process to the next process. In this inspection process, the light-shielding film is defective and defective (projections due to foreign matter in the light-shielding film, white pins (white spots in the light-shielding film), black pins (parts of the light-shielding film remaining or adhered on the pixels) It is effective to apply the method for regenerating the color filter light-shielding film according to the present invention when (1) or (2) occurs.

A method of reproducing a light-shielding film for a color filter according to the present invention is characterized in that only the light-shielding film is removed without damaging each pixel, and a light-shielding film is formed again in a gap between the pixels.

Specifically, it is preferable to immerse the color filter in a stripping solution. In this case, a liquid having the property of dissolving or swelling only the light-shielding film without swelling each pixel is used as the stripping liquid.

As the stripping solution, an inorganic alkali, an organic alkali or a surfactant can be used alone or in combination of two or more. As inorganic alkalis, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium phosphate, sodium metasilicate, sodium carbonate, potassium carbonate,
And ammonium carbonate. Examples of the organic alkali include monoethanolamine, diethanolamine, triethanolamine, tetraalkylammonium hydroxide, and ammonium silicate. Examples of the surfactant include anionic surfactants such as sodium lauryl sulfonate, sodium octyl sulfonate, and sodium doenylbenzene sulfonate;
Nonionic surfactants such as alkyl ethylene oxide monomethyl ether and the like can be mentioned. In addition, ethylene glycol monophenyl ether, ethylene glycol monobutyl ether, n
-An organic solvent such as propyl alcohol, ethyl alcohol and butyl alcohol may be added.

A color filter (defective product) is added to the above stripping solution.
Is immersed for a certain period of time, and then, if necessary, ultrasonic cleaning and spray cleaning are performed to further enhance the effect of dissolving or swelling the light-shielding film.

The above-mentioned stripping solution can be used when the pixel and the light-shielding film are made of any of the known materials. However, it is preferable to inspect and strip after forming the light-shielding film and before performing post-baking. . If it is immersed in a stripping solution after the post-baking, the light-shielding film hardly swells and is hardly stripped even by ultrasonic cleaning, which is not preferable.

It should be noted that if the stripping solution is too strong, the immersion time is too long, or the temperature of the stripping solution is too high, the pixels may be damaged. That is, the concentration of the stripping solution is preferably 1 to 20% by weight, more preferably 2 to 10% by weight. As the immersion time,
0.5 to 16 hours are preferable, and more preferably, 1 to 4 hours.
Time. The temperature of the stripping solution is preferably from 15 to 50 ° C, more preferably from 20 to 30 ° C.

As a method of preventing damage to the pixels, it is a matter of course that the conditions for removing the light-shielding film are optimal as described above. However, after forming the pattern of the pixels, sufficient post-baking is performed to remove the pixels. The effect can be further enhanced by not dissolving or swelling in the liquid.

[0023]

【Example】

Example 1 A colored paste in which red, green, and blue organic pigments were dispersed in an N-methylpyrrolidone solution of polyamic acid (25% by weight) was prepared. Each of these coloring pastes was applied on a glass substrate by a spinner, and a pattern was formed by an ordinary method using an etching method using a positive resist. When the pattern formation of the first color is completed,
The post-baking was performed for 1 hour, the second color pattern was formed, and the post-baking was performed again at 300 ° C. for 1 hour.
Further, a third color pattern was formed, and post-baking was performed at 300 ° C. for 1 hour to form an RGB pattern. At this time, a gap for a light-shielding film of 15 μm was provided between each color.

A photosensitive black paste obtained by dispersing a black component in a photosensitive polyamic acid solution (“Photo Nice” manufactured by Toray Industries, Inc.) is applied on the entire surface of the R, G, and B patterns thus prepared by a spinner. The substrate was dried at 150 ° C. for 30 minutes, exposed from the back side of the substrate, and developed to form a black light-shielding film between each pixel.

The above operation was performed on 50 sheets, and an inspection was performed on the presence or absence of damage to the projections, white pins, black pins, and other light-shielding films due to foreign matter in the light-shielding film. As a result, it was found that there were 18 defective products.

The color filters of these defective products were applied to a stripping solution containing a 5% by weight aqueous solution of sodium metasilicate, sodium carbonate and alkyl ethylene oxide monomethyl ether at a ratio of 5: 2: 1 (weight ratio) at 20 ° C. After immersion for 1 hour, it was washed with water spray. As a result, in all of the 18 sheets, only the light-shielding film could be completely removed, and the R, G, and B patterns were not damaged at all. A light-shielding film was formed on the R, G, and B pattern products thus reproduced again using the photosensitive black paste in the same manner as described above.

As a result of similarly inspecting the 18 color filters, 16 were good and two were defective. Table 1 summarizes the results. That is, when the light-shielding film was not regenerated (No. 1), the process yield was 64%, but by regenerating the light-shielding film (No. 2), the yield was improved to 96%.

[0028]

[Table 1] Example 2 5% by weight of an acrylic polymer obtained by copolymerizing acrylic acid, styrene and methyl methacrylate in equal amounts, 3% by weight of trimethylolpropane triacrylate, 6% by weight of carbon black, 5% by weight of polyvinyl butyral, 1% by weight of α-aminoacetophenone 80% by weight of butyl cellosolve
Were mixed and dispersed in a bead mill to prepare a photosensitive paste for forming a light-shielding film.

This paste was mixed with R, G,
The entire surface was coated with a spinner on the glass substrate on which the B pattern was formed, and dried at 80 ° C. for 5 minutes. At this time, the film thickness was 1.5 μm. Next, exposure was performed from the back side of the substrate, and development was performed to form a black light-shielding film between the pixels.

The above operation was performed on 50 sheets, and an inspection was performed on the presence or absence of damage to the projections, white pins, black pins, and other light-shielding films due to foreign matter in the light-shielding film. As a result, it was found that there were 15 defective products.

These defective color filters were prepared by mixing sodium metasilicate, sodium carbonate, and alkyl ethylene oxide monomethyl ether at a ratio of 5: 2: 1 (weight ratio).
After being immersed in a stripping solution of a weight% aqueous solution at 20 ° C. for 1 hour, the film was washed with water spray. As a result, in all of the fifteen sheets, only the light-shielding film could be completely removed, and the R, G, and B patterns were not damaged at all. A light-shielding film was formed on the reproduced R, G, and B pattern products again using the photosensitive black paste in the same manner as described above. This 15
As a result of similarly inspecting one color filter, 1
Four sheets were good and one was defective. Table 2 shows the results.
Summarized in That is, when the light-shielding film was not regenerated (No. 1), the process yield was 70%, but by regenerating the light-shielding film (No. 2), the yield was improved to 98%.

[0032]

[Table 2]

[0033]

According to the present invention, the process yield can be increased and the overall cost can be reduced even if a defective product occurs when the light-shielding film of the color filter is formed by the post-installation method.

Claims (2)

(57) [Claims] 1. After forming pixels of a plurality of colors on a transparent substrate, a color filter produced by forming a light shielding film in a gap between the pixels is immersed in a stripping solution to remove only the light shielding film. Forming a light-shielding film in the gap between the pixels again. 2. A stripping solution, inorganic alkali, a method of reproducing according to claim 1 color filter shielding film, wherein in containing at least one selected from the group of organic alkali and surfactants.