JPH07294713A - Color filter and its production - Google Patents

Abstract

PURPOSE:To thin a color filter itself and to improve the resistance of the upper and side faces of each picture element by hardening the side wall of a pattern consisting of a colored resin and covering the whole body with a transparent conductive film. CONSTITUTION:Colored picture element patterns 30R, 30G and 30B are formed on one side of a supporting substrate 20 as the base of a color filter 100, and the side wall 31 of the pattern consisting of a colored resin is hardened as compared with the other parts. The one side of the substrate 20 including the patterns 30R, 30G and 30B is wholly covered with a transparent conductive film 50 without an intervening protective film. The film 50 acts as the protective film of the patterns 30R, 30G and 30B, and the protecting function by the protective film is reinforced by the hardened side wall 31 of the pattern itself. The hardened side wall is directly covered with the film 50, and the upper face of the pattern is preferably covered with the film 50 with an intervening photoresist film 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique effective in thinning a color filter, and more particularly to a technique using a transparent conductive film as a protective film for a color filter.

[0002]

BACKGROUND OF THE INVENTION Colorants (dyes, pigments) as one of color filters used for color display of liquid crystal displays and the like.
It is known that a pixel pattern of each color such as red, green, and blue is formed by a colored resin material mixed in advance with. In order to protect the surface of this type of color filter, generally, the entire surface of the color filter is covered with a protective film (overcoat), and a transparent conductive film is formed on the protective film. There are various materials for the protective film. For example, JP-A-4-5120.
In JP-A No. 2-1800, a photosensitive acrylic resin is disclosed.
No. 66, epoxy resin;
In Japanese Patent No. 233720, inorganic silicon dioxide is used. The transparent conductive film on the protective film is an electrode for driving a liquid crystal display or the like together with the counter electrode, and is made of a known material such as ITO.

[0003]

However, if the protective film is formed between the transparent conductive film and the color filter, not only the number of steps increases but the cost also increases, but also the failure rate increases. The thickness of the color filter is increased by the amount of the protective film, which is disadvantageous in reducing the thickness. Therefore, the inventors tried to form a color pixel pattern by a photolithography technique, and then form a transparent conductive film without separately forming a protective film thereon. As a result, the upper surface portion of each color pixel pattern (particularly, the portion covered with the photoresist) has sufficient resistance without interposing a protective film, while the side wall portion of the etched pattern has resistance. It turned out that there was a problem. According to the examination, when the thickness of the transparent conductive film 50 is viewed, when the upper surface portion of each color pixel pattern is 1, the sidewall portion of the pattern is, for example, about 0.3 to 0.5, and the coverage of the sidewall portion is good. Absent.

[0004]

SUMMARY OF THE INVENTION The present invention has been made based on the results of the above examination, and it is possible to reduce the thickness of the color filter itself. Moreover, not only the upper surface portion of each filter pixel but also the side surface portion thereof It is an object of the present invention to provide a technique capable of effectively improving resistance. Also,
Another object of the present invention is to provide a technique suitable for manufacturing such a color filter which is thin and has excellent durability. In particular, another object of the present invention is to provide a technique suitable for a color filter using a polyimide-based colored resin material.

[0005]

In a color filter 100 according to the present invention, as shown with reference to FIG. 1 corresponding to an embodiment, a support substrate 20 serving as a base of the color filter, and a color pixel pattern formed on one surface of the support substrate 20. 30R, 30
G, 30B, a pattern in which the side wall portion 31 of the pattern made of a colored resin material is hardened as compared with other portions, and one surface of the support substrate 20 including the color pixel patterns 30R, 30G, 30B is A transparent conductive film 5 that covers the entire surface without a protective film that covers the entire surface
It has 0 and. That is, the color filter 100
Is the transparent conductive film 50 for each color pixel pattern 30R, 30
It serves as a protective film for G and 30B, and the protective function of the protective film is reinforced by the side wall portion 31 of the hardened pattern itself.

As the colored resin material, a material containing a resin such as epoxy, acryl or polyimide, and a pigment or a dye mixed in these resins can be used. Among them, the polyimide type is particularly excellent. This is because the resin material itself is more resistant than other materials, and the side wall portion of the pattern can be easily hardened. In the case of a polyimide system, the patterned material is usually composed mainly of a polyimide precursor, and the exposed side wall portion can be hardened by subjecting the side wall portion to a diamine treatment. This diamine treatment can be easily performed by dipping or spraying the support substrate of the color filter while leaving the photoresist covering the upper surface of the pattern. In Japanese Patent Laid-Open No. 63-6503, which shows the same diamine treatment, the diamine treatment is performed in a state where the photoresist is peeled off. However, in the present invention, an acrylic photoresist having high transparency which is not affected by the diamine treatment. , Which protects the pattern, so there is no bleaching problem with diamine treatment. Therefore, without worrying about decolorization, various coloring materials,
For example, a triphenylmethane-based dye that is likely to be decolorized in an alkaline region having a pH of 8 or more can be positively used.

Here, the diamine treatment for the polyimide type will be briefly described. The processing here means
The diamine solution is brought into contact with a polyimide resin pattern, and a dipping method or a spray method is preferable. Although diamine compounds include aromatic compounds as well as aliphatic compounds, aromatic compounds are not effective because they have poor reactivity. Aliphatic diamine solutions include ethylenediamine, heptanediamine, hexamethylenediamine and other aliphatic diamine compounds, benzene, ethanol and other alcohols, methyl cellosolve and other cellosolves,
It is a liquid dissolved in an organic solvent such as trichlene, water, or a mixture thereof. In the case of dipping, dipping is performed for tens of seconds to tens of minutes, and then rinsing is performed with the above-mentioned appropriate solvent. In the case of spraying,
After spraying, do the same rinse. When performing these treatments, the liquid temperature of the solution may be kept between room temperature and the boiling point. When the treatment with the aliphatic diamine solution is performed, the amine reacts with the carboxyl group in the polyimide precursor molecule to form an amide (that is, a crosslinking reaction occurs), and the portion of the treated pattern does not undergo treatment. Hardened compared to other parts.

When a color resin material of the polyimide type is used, as a method of manufacturing the color filter 100, as shown in FIG. 2 to FIG. 6 in addition to FIG.
Those that include at least the steps B and C are preferable. (A) A step of patterning color pixels 30R (30G, 30B) of a color filter made of a polyimide-based colored resin material on one surface of the support substrate 20 by a photolithography technique, (B) a photoresist 70 after the patterning. The color pixel pattern 30R (30G, 3
0B), a step of hardening the exposed side wall portion 31 of the pattern by performing a diamine treatment in the state where (C) the partially hardened color pixel pattern 30.
A step of forming the transparent conductive film 50 on one surface of the support substrate 20 including R, 30G, and 30B without a protective film covering the entire surface. Of course, the steps A to B are repeated for each color, and after the B diamine treatment and the post bake treatment to finish the treatment for all color pixels, the transparent conductive film 50 is formed.

[0009]

In such a color filter 100, the transparent conductive film 50 directly covers the pixel patterns 30R, 30G, 30B of the respective colors (the photoresist 70 used for patterning may be left or peeled off). May be). Therefore, the color filter 100 becomes thin because there is no protective film covering the entire portion below the transparent conductive film 50. Further, since the side wall portion 31 of each color pixel pattern 30R, 30G, 30B is hardened as compared with the other portions, the side wall portion 3 is irrespective of whether the transparent conductive film 50 covering the side wall portion 31 is thin.
A resistance of 1 is sufficient.

[0010]

[Embodiment of Color Filter] FIG. 1 shows a sectional structure of a color filter 100 according to an embodiment of the present invention. The color filter 100 includes three color pixel patterns 30R, 30G and 30B of red, green and blue on a transparent support substrate 20 such as a glass plate or an acrylic resin plate. Each of the color pixel patterns 30R, 30G, 30B has a size of, for example, about 80 to 200 μm, and a large number of them are arranged in a matrix. Since each color pixel pattern is formed for each color, ideally the gap between adjacent color pixel patterns can be made zero. However, in general, in order not to overlap adjacent color pixel patterns,
Provide a small gap. A so-called black matrix can be formed in the gap. Such a gap is narrow, and therefore, the entire pixel patterns 30R, 30G, 30B of each color on the support substrate 20 are entirely covered with the transparent conductive film 5.
Even if it is covered with 0, the coverage of the side wall portion 31 of each pattern is not so good. However, this color filter 100
Since the side wall portion 31 is hardened, the side wall portion 31 can also have resistance close to that of the upper surface portion.

[0011]

[Examples of Manufacturing Method] FIGS. 2 to 6 are views showing processing steps for manufacturing the color filter 100 shown in FIG. In the example shown here, the photoresist 70 used for patterning is left as it is on the pattern of each color pixel. First, a coloring resin 40 made of dye-dispersed polyimide is applied on the transparent substrate 20. The film thickness of the colored resin 40 is about 1 to 2 μm. The coating material of the dye-dispersed polyimide is a solution containing a polyimide precursor, a dye, and methyl cellosolve as a solvent, and a spin coater can be used for coating.

Next, the applied colored resin 40 is prebaked. As a pre-baking condition, for example, heat treatment is applied on a hot plate at 130 ° C. for 10 minutes. After this pre-baking, the photoresist 6 is applied on the colored resin 40.
0 is evenly applied (FIG. 2). The film thickness of the photoresist 60 is 0.3 to 2 μm, preferably 0.3 to 1 μm. As the photoresist 60, not only the negative type,
Although a positive type can also be used, a negative acrylic type (CFPR CL-015, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is used here. Application is by a spin coater. After coating, the photoresist 60 is prebaked. The pre-baking condition is 1 on the hot plate.
A heat treatment at 00 ° C. for 10 minutes is applied.

After prebaking, the photoresist 60 is exposed through a predetermined mask 90 (FIG. 3). The exposed portion of the negative photoresist 60 reacts and is not dissolved in a developing solution or the like. Then, the process of development and etching is started. In this case, since the lower layer colored resin 40 and the upper layer photoresist 60 are both soluble in alkali, development of the photoresist 60 and etching of the colored resin 40 are performed at the same time, and the predetermined color pixel pattern 30 is formed.
R can be obtained (FIG. 4). As the treatment liquid, for example, 0.5% Na ₂ CO ₃ is used. About 60 seconds is suitable for the etching time.

After such etching, the pattern in which the side wall portion is exposed is treated with diamine for hardening. For example, a 0.25% hexamethylenediamine solution may be sprayed on the pattern side of the supporting substrate 20 (FIG. 5).
At this time, it is preferable to perform the spray from diagonally above while rotating the support substrate 20. By spraying obliquely from above with rotation, the processing solution can be effectively spread to the side wall portion located in the narrow gap. Following this diamine treatment, color pixel pattern 30
Post Bake R. This post bake is for promoting and strengthening the crosslinking of the pattern 30R, and as its condition, for example, heat treatment at 220 ° C. for 30 minutes in a clean oven is applied.

The above processing steps are performed on the remaining green and blue color pixel patterns 30G and 30B to obtain all three color patterns on one surface of the support substrate 20 (FIG. 6). The three-color pattern is entirely covered with a transparent conductive film 50 such as ITO, and the color filter 1 shown in FIG.
00 is completed.

If the photoresist 70 on each color pixel pattern is left, the removal process can be omitted, and the upper surface of the pattern can be protected more reliably. Photoresist 70
Alternatively, the transparent conductive film 50 may be formed after removing the.

[0017]

According to the present invention, since the transparent conductive film 50 is entirely covered without separately forming a protective film on each color pixel pattern 30R, 30G, 30B on the support substrate 20, the color The filter 100 can be made thin, and the pixel patterns 30R, 30G, 30 of the respective colors can be formed.
Since the side wall portion 31 of B is hardened, the resistance of the side surface portion can also be effectively increased.

[Brief description of drawings]

FIG. 1 is a sectional structural view showing an embodiment of a color filter according to the present invention.

FIG. 2 is a diagram in the middle of the steps showing the manufacturing method, and is a diagram showing a state where the photoresist application is completed.

FIG. 3 is a diagram in the middle of the steps showing the manufacturing method, and is a diagram showing an exposed state.

FIG. 4 is a diagram in the middle of the steps showing the manufacturing method, and is a diagram showing a state in which development and etching have been completed.

FIG. 5 is a diagram in the middle of the steps showing the manufacturing method, and is a diagram showing a state of hardening treatment.

FIG. 6 is a diagram in the middle of the steps showing the manufacturing method, and is a diagram showing a state in which the post bake is finished.

[Explanation of symbols]

 20 Support substrate 30R, 30G, 30B Color pixel pattern 50 Transparent conductive film 70 Photoresist 100 Color filter

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shinji Mizumoto 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Kyodo Printing Co., Ltd.

Claims (6)

[Claims] 1. A support substrate serving as a base of a color filter, and a color pixel pattern formed on one surface of the support substrate, wherein a sidewall portion of the pattern made of a colored resin material is hardened as compared with other portions. A color filter comprising: a pattern; and a transparent conductive film that covers the entire surface of a support substrate including such a color pixel pattern, without interposing a protective film that entirely covers the surface. 2. The color filter according to claim 1, wherein the transparent conductive film directly covers the side wall portion of the hardened pattern and covers the upper surface portion of the pattern via a photoresist film. 3. The color filter according to claim 1, wherein the color pixel pattern is made of a colored resin material containing a polyimide resin and a coloring material contained in the resin. 4. A method of manufacturing a color filter, comprising at least the following steps A, B and C: (A) A step of patterning color pixels of a color filter made of a polyimide-based colored resin material on one surface of the support substrate by a photolithography technique, (B) leaving the photoresist on the pattern of the color pixels after the patterning. In a state where the diamine treatment is performed to harden the exposed side wall portion of the pattern, (C) one surface of the supporting substrate including the partially hardened color pixel pattern is entirely covered. Without a protective film
A step of forming a transparent conductive film. 5. After the diamine treatment in the step B, the pattern of color pixels is post-baked and the same treatment is completed for all the color pixels, and then the transparent conductive film in the step C is formed. Item 4. A method for manufacturing a color filter according to item 4. 6. The method of manufacturing a color filter according to claim 4, wherein the pattern of the color pixels includes a dye as a coloring material.