JPH0695162B2 - Color filter manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a color filter.

Conventionally, water-soluble photosensitive substances for colored base materials in the production of color filters include hydrophilic resins such as egg white, glue, casein, polyvinyl alcohol, and gelatin, and dichromate and chromate as photosensitizers (photopolymerization initiators). Alternatively, there is one to which a diazo compound is added, both of which are negative type.

As a method of use for producing a color filter, the following processes (Japanese Patent Publication No. 52-17375, Japanese Patent Publication No. 52-173) are used.
No. 76 specification) is used.

That is, (1) preparation of a photosensitive solution base, (2) addition of a photosensitive main agent, (3) coating on a substrate, (4) pre-baking,
(5) Ask exposure, (6) Hot or cold water development, (7)
Burning and (8) dyeing (usually dyeing with an acid dye) are sequentially performed.

Since the pot life of the photosensitive solution is short here, it is general to add the main photosensitive agent immediately before use.

However, the conventional gelatin photosensitizer for color filter production is a high molecular weight gelatin with a molecular weight of 150,000 to 250,000 (for photographic use) Since gelatin, general industrial gelatin, edible gelatin, etc.) are used, most of the amides in gelatin have been converted to carboxyl groups during the lime treatment process, and the isoelectric point was low. That is, in the photosensitive solution using the conventional lime-processed gelatin, the dyeing position (that is, amino group) by the acid dye is small, and therefore, in order to obtain the dyeing density required for the color filter, the coating film thickness of about 2 to 3 μm. Needed.

However, in recent years, there has been a demand for manufacturing a mosaic filter having a pattern dimension of about 5 μm, as the precision of the color mosaic filter for a solid-state imaging device has increased.
It was not possible to obtain sufficient pattern accuracy with the coating thickness of.

On the other hand, since the molecular weight of gelatin is as high as 150,000-250,000, at a gelatin concentration of 10-20%, almost all gels at 30-40 ° C.
% Does not gel at about 25 ± 5 ° C. ).

Therefore, if the coating process of the gelatin photosensitive solution is performed at 25 ± 5 ° C, that is, at room temperature, even if the photosensitive solution is heated in advance, gelation may occur during the coating and smooth coating may not be performed, or the film thickness may be controlled. Was also very difficult. Therefore, in general, the coating operation is currently performed at a constant temperature of 40 to 45 ° C, but considering the operation of a constant temperature chamber at 40 to 45 ° C and the rationalization of the coating process, gelatin that does not gel near room temperature is used. A method using a photosensitizer has been desired.

The present invention has been made in view of the drawbacks of the color filter production using the gelatin-based photosensitive solution described above, and an object thereof is a gelatin-based photosensitive solution which is easy to dye,
That is, there are many amino groups in the molecule, and at room temperature (25 ± 5
It is an object of the present invention to provide a method for producing a color filter using a photosensitive material for producing a color filter which does not gel even at (° C.).

As a gelatin manufacturing process, the process shown in FIG. 1 is known, but the major difference between acid-processed gelatin and lime-processed gelatin is that the finished products have different isoelectric points. That is, as shown in FIG. 1, skins, bones, etc. are washed with water, soaked in an acid (hydrochloric acid, etc.) and extracted, and the acid-treated gelatin produced through the steps from filtration to mixing has a pH of 7 to
It is about 9 and contains a large amount of amino groups, whereas in lime-processed gelatin, most of the amino groups are changed to carboxyl in the lime-processing step, so the isoelectric point is about pH 4.8-5.1.

Therefore, according to the study by the present inventor, it has been clarified that the acid-processed gelatin has more dyeing positions (that is, amino groups) with respect to the acid dye and has a property of being easily dyed. Therefore, the present invention, for example, the collagen in the skin or bone is previously treated with hydrochloric acid to remove unnecessary organic substances, and the extracted acid-treated gelatin is further decomposed with a proteolytic enzyme or the like to reduce the molecular weight to 5000 to 70,000. Prepared by adding the photopolymerization initiator and the auxiliary agent to prepare a photosensitive solution, coating at room temperature, exposing, developing with cold water, and dyeing with an acid dye. It enables uniform coating at room temperature while preventing gelation at the time, realizes thinning of the colored base film, and forms a filter pattern with a high dyeing concentration, which is a suitable method for manufacturing color filters. It is characterized by being provided.

The acid-processed gelatin with a low molecular weight is almost the same as ordinary lime-processed high-molecular gelatin except that it is easily dyed with an acid dye and has a low gelling temperature. It has been found that it is also possible to dissolve it in water, ie to develop it.

Description of Examples In advance, acid-treated gelatin extracted from collagen in the skin or bone by hydrochloric acid treatment to remove unnecessary organic substances,
Further, an acid or an alkali is added to decompose and desalting is carried out with an ion exchange resin to prepare a low molecular weight gelatin having an average molecular weight of 5000 to 70,000 (acid-treated residence molecular gelatin).

Next, water is added to a predetermined concentration, and a photopolymerization initiator (photosensitive main agent such as ammonium dichromate) and an auxiliary agent (such as alcohol, chrome alum, tincture of benzoin etc.) are added to prepare a photosensitive solution. To do. Then, after the above-mentioned step, that is, the removal of bubbles, it is applied onto a predetermined glass substrate, prebaked, and then subjected to ultraviolet exposure and cold water development (3 minutes) using a photomask.
After burning at 0 ° C, a color filter is manufactured by dyeing with an acid dye at 800 ° C for about 10 minutes.

Incidentally, when it is desired to form a color filter of a plurality of colors on the substrate, it is natural that a transparent dye-proof resin film is formed by coating on the colored color filter, and the dye-proof resin is again used. A mosaic color filter having a plurality of colors can be easily manufactured by applying a photosensitive solution on the film and repeating pattern formation and dyeing.

Hereinafter, specific examples of acid-processed gelatin as a main component for the photosensitive liquid used for producing the color filter of the present invention and comparative examples having lime-processed gelatin as a main component will be described.

(Example 1) Each of the following substances: ○ water 1000cc ○ acid-treated gelatin (molecular weight 5,000 to 20,000) 400g ○ ammonium dichromate 40g ○ alcohol 60cc ○ benzoin tincture 50cc ○ chromium alum (0.2 aqueous solution) 20cc well mixed and dissolved (50-60 ℃), cooled to 20 ℃ and left for one day, but no gelation occurred and viscosity was 140cps at room temperature.
Met. After coating on a glass substrate, UV exposure and cold water development (3 minutes) were performed using a chrome mask with a test pattern formed, and then dyeing was performed at 80 ° C for 10 minutes with Eriocin Scarletton RE of Ciba-Geigy Japan. Then, the pattern shown in FIG. 2 (a) was obtained, and good dyeing was confirmed. At this time, the thickness of the photosensitive film was 0.68 μm.

(Comparative Example 1) The same procedure as in Example 1 was carried out except that the amount of ammonium dichromate as a photosensitizing agent was 40 g, and 300 g of low-molecular gelatin treated with gelatin / lime (molecular weight 10,000 to 20,000) was used. No gelation occurs, the viscosity is about 210 cps,
An equivalent pattern was formed, but after that, it was dyed with Eriocin Scarlet RE of Japan Ciba-Geigy Co., Ltd. at 80 ° C. for 10 minutes, and the result was as shown in FIG. 2 (b). Similarly, even at 0.7 μm, it was not dyed as much as in Example 1 as can be seen from FIG.

The visible spectral characteristics are shown in FIG. In the figure, (a) shows the case of the acid-processed gelatin of Example 1 and (b) shows the case of the lime-processed gelatin of Comparative Example 1.

(Comparative Example 2) In the above-mentioned Example 1, the amount of ammon dichromate which is a photosensitizing agent was 25 g, and gelatin was treated with lime (molecular weight: 100,000 to 25).
The experiment was carried out under the same conditions except that 150 g of photographic gelatin of 10,000) was used, but the gel remained completely gelated even at room temperature of 25 ° C. Then, after re-dissolving at 50 ° C., coating, exposure and development were performed, but development was performed for 10 minutes with cold water, but a sharp pattern was not formed.

The result after staining is shown in FIG.

(Example 2) Each of the following substances: ○ water 1000cc ○ acid-treated gelatin (molecular weight 30,000 to 70,000) 200g ○ potassium dichromate 10g ○ ammonium dichromate 30g ○ lead nitrate 2.5g ○ alcohol 30cc well mixed and dissolved ( After 50-60 ℃), it was cooled to 20 ℃ and left for one day, but no gelation occurred and the viscosity was 160 cps. Also, after coating on a glass substrate, UV exposure using a chrome mask on which a test pattern is formed is about 3μ.
A pattern of m line width could be formed. In addition, the first embodiment
When stained under the same conditions as above, the same degree of staining as in Example 1 was obtained.

Example 3 Gelation did not occur even under the same conditions as in Example 2 except that 300 g of acid-treated gelatin (molecular weight 5,000 to 20,000) was used as gelatin, and the viscosity was about 140 cps and that of Example 2 Similar patterns and stains were obtained.

(Comparative Example 3) In the same manner as in Example 2, except that 150 g of lime-processed gelatin (molecular weight 50,000 to 250,000) for general industry was used as gelatin, the experiment was conducted under the same conditions until ammonium dichromate was added. Although gelation occurred at around 30 ° C, gelation did not occur after addition of ammonium dichromate. On the other hand, the pattern formation and dyeing density were the same as in Comparative Example 1.

In addition to the above Examples 1 to 3, gels prepared by mixing a small amount of acid-treated or lime-treated high-molecular gelatin (molecular weight 100,000-20,000) with acid-treated low-molecular gelatin (molecular weight 5,000-20,000) are also gels at room temperature. It was possible to prepare a sensitizing solution which does not cause deterioration and has a high viscosity and which is well dyed with an acid dye. This example is shown below as Example 4.

(Example 4) The same as Example 1 except that 300 g of acid-treated low-molecular gelatin (molecular weight 5,000 to 20,000) and 40 g of lime-treated high-molecular gelatin (molecular weight 100,000 to 200,000) were mixed with gelatin. When experimented under the conditions, the viscosity at room temperature
The same results as in Example 1 were obtained except that the value was 250 cps.

The above-mentioned photosensitive solution has been described in the case where dichromate is used as the photopolymerization initiator, but it is clear that the same effect can be obtained with a radical type initiator, for example, a diazo compound type or a peroxide type. is there. The benzoin tincture, which is an auxiliary agent used in the examples, has the effect of controlling and hardening the star of gelatin, and alcohol has the effects of preventing foaming and improving spreadability.

As described above, acid-treated low molecular weight gelatin (molecular weight 5,000
~ 30,000, or 30,000 to 70,000) is prepared as a main component to obtain a gelatin photosensitive solution, which has good dyeability with acid dyes and does not cause gelation even at room temperature. Therefore, the production process of the color filter can be greatly simplified by producing a gelatin-based photosensitive liquid having such a slow viscosity change and using it. That is, by using this photosensitive solution, the film thickness can be easily controlled even when the coating process is performed at room temperature, and moreover, uniform coating can be performed. Will be very large. Further, the developing step can be performed with cold water, which is very advantageous.

Furthermore, the dyeing density per unit thickness can be increased by using acid-treated gelatin. That is,
Even if the coating film thickness is about 0.5 μm, a dyeing density that can be sufficiently used as a color filter can be obtained, so that it is easy to form a fine pattern of about 5 μm. That is, as is clear from FIG. 3, the lime-processed gelatin exhibited only extremely bad visible spectral characteristics, but according to the present invention, good visible spectral characteristics as a color filter can be obtained, and thin and fine colors can be obtained. It can greatly contribute to the realization of a filter pattern.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a general gelatin production process, and FIG. 2 (a) is an enlarged view of a pattern formed by using acid-treated gelatin in Example 1 of the present invention. 2 (b) is an enlarged view of a pattern formed by using the lime-processed gelatin photosensitive liquid of Comparative Example 1 for comparison with Example 1, and FIG. 3 is Example 1 of the present invention and comparison therewith. FIG. 4 is a diagram showing visible spectral characteristics of a dyed product after forming a pattern using the photosensitive solution of Comparative Example 1. FIG. 4 shows an attempt to form a pattern using the photosensitive solution of Comparative Example 2 in cold water development. Is an enlarged pattern diagram showing that pattern formation does not go well.

Continuation of the front page (56) References JP-A-57-85051 (JP, A) JP-A-58-33208 (JP, A) Jaromir Kosar, "Light-Sensitive Systems: Chemistry and Application Noflicization of Applications". Photographic process "1965 pages 55-62

Claims (1)

[Claims] 1. An acid-treated gelatin containing a large amount of amino groups, which is obtained by acid-treating collagen to remove unnecessary organic substances without treating it with lime, and further decomposes it to give a molecular weight of 5000-70.
The main component is gelatin and water produced by reducing the molecular weight to 000, a step of preparing a photosensitive solution by adding a photopolymerization initiator and an auxiliary agent, a step of applying the photosensitive solution onto a substrate at room temperature, Exposing using a photo mask of No. 2, and developing with cold water to form the required gelatin pattern,
A method of manufacturing a color filter, comprising the step of forming the pattern and then dyeing the pattern with an acid dye.