JPS62127702A - Preparation of color filter having superior characteristics and high precision - Google Patents

Abstract

PURPOSE:To disperse molecules of dye sufficiently and to improve reproducibility of dimension in a stage for migrating a dye contained in an ink layer in gaseous state into an activated film layer by heating and dyeing the activated layer by performing heating in the atmosphere under reduced pressure. CONSTITUTION:An activated film layer comprising activated alumina and/or activated silica is formed on a transparent substrate; metal mask having a desired pattern hole formed thereon is mounted on the activated film layer. Further, a transfer sheet provided with an ink layer contg. a sublimable dye or/and a vaporizable dye by thermal fusion is mounted thereon. The transfer sheet is heated at a temp. where the dye migrates in vaporized state into fine pores in the activated film layer, and in the atmosphere under reduced pressure; thus, a fine pattern having sufficient dyeing concn. is obtd. Then, a hard and transparent resin is coated on the fine pores on the activated film layer. An overcoated layer is obtd. be heating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a color filter with high physical properties and high precision used in various display devices.

[Conventional technology and its problems]

Conventionally, as a method for manufacturing color filters, a method of dyeing gelatin using a photolithography method is known. This method cannot be said to be a method that fully satisfies consumers because the manufacturing process is complicated and the physical properties of the color filter are poor.

As a result of intensive research, the present inventors have previously invented the so-called metal mask method (see Japanese Patent Application No. 59-97210). That is, this method includes the steps of forming an active film layer made of at least one of activated alumina or activated silica on a transparent substrate, placing a metal mask having a predetermined pattern of holes on the active film layer, and then A step of placing a transfer sheet having an ink layer containing a sublimable dye or/and a dye that vaporizes by heat melting, and by heating, the dye in the ink layer is transferred in a gaseous state to the active film layer and dyed. Step 1 Next, by repeating the steps of removing the transfer sheet and the metal mask according to the number of colors required, patterns corresponding to the pattern holes of the metal mask are sequentially formed in the active film layer, Finally, an overcoat layer is provided to seal the upper part of the fine pores of the active film layer, thereby producing a color filter. According to this method, the drawbacks of the photolithography method described above could be solved, but the following new problems arose. In other words, since a metal mask is interposed between the transparent substrate and the transfer sheet, the dye is not thermally transferred in a close contact state as in conventional transfer printing, but the dye is always vaporized and travels a distance equivalent to the thickness of the metal mask. There is a need to. Therefore, a large amount of energy (heat and time) was required due to effects such as air resistance. As a result, a considerable amount of distortion occurred due to expansion of the metal mask, which had a large negative impact on accuracy. In addition, the dye used must be easily vaporized, which narrows the range of dye selection, making it impossible to use dyes with excellent dyeability and thermal stability, and causing a decline in the physical properties of color filters. was. Therefore, in order to solve these problems, we attempted to use a metal mask with a thin film. However, due to lack of strength, the metal mask was damaged and there were problems with durability.

[Configuration of the present invention]

Therefore, as a result of intensive research in view of the drawbacks of the conventional method described above, the present inventor has completed the present invention which solves the various drawbacks of the conventional method by improving the so-called metal mask method described above. .

That is, the present invention includes a step of forming an active film layer made of at least one of activated alumina or activated silica on a transparent substrate, placing a metal mask having a predetermined pattern of holes on the active film layer, and then A step of placing a transfer sheet having an ink layer containing a sublimable dye or/and a dye that is heat-melted and vaporized on the substrate, and by heating, the dye in the ink layer is transferred in a gaseous state to the active film layer and dyed. Step 1 Next, by repeating the steps of removing the transfer sheet and the metal mask according to the number of colors required, patterns corresponding to the pattern holes of the metal mask are sequentially formed in the active film layer, A method for producing a color filter by finally providing an overcoat layer for sealing the upper part of the micropores of the active film layer; characterized in that the heating is performed in a reduced pressure atmosphere with high physical properties and high precision. This is a method for manufacturing a color filter.

The present invention will be explained in detail below. The transparent substrate used in the present invention may be one commonly used in liquid crystal display devices, and usually a glass plate is preferably used.

An active film layer made of at least one of activated alumina and activated silica is formed on the transparent substrate. To form this active film layer, first coat colloidal alumina, colloidal silica, or a mixture of both on the surface of a transparent substrate, dry it, and then heat it at 350°C to 850°C for 10 minutes.
It is sufficient to bake for 180 minutes. The active membrane layer obtained in this way is transparent and has many micropores formed therein.
This becomes the dyed layer. In addition, the active film layer has its transparency,
Considering surface hardness, dye receptivity, etc., 0.5 μm to 10
A layer thickness of .mu.m, preferably 1.5 .mu.m to 5 .mu.m is desirable. This is because when the thickness of the active film layer increases, it tends to whiten and become opaque, and on the other hand, when the layer thickness decreases, the dye receptivity decreases and dyeing density cannot be obtained.

Further, the material of the metal mask used in the present invention may be any metal as long as it is possible to form holes in a predetermined pattern. The film thickness is 0.005 to 0.5 mm, preferably 0.005 to 0.5 mm.
It is about 0.007 to 0.05 mm. The above-mentioned predetermined pattern is formed by electrohoming, chemical etching,
It is formed by electrical discharge machining, laser machining, etc. If the object is a color filter for a don't-matrix type liquid crystal display device, it must have a sufficiently fine door pattern hole accuracy.

Next, the transfer sheet used in the present invention includes a base sheet made of a film or paper made of a polymeric material having heat-induced heat properties, and an ink layer made of a dye, a binder, etc. as the minimum necessary constituent layers. The dye in this case is a sublimable dye or/and a dye that is thermally melted and vaporized, and specifically, disperse dyes, metal-free oil-soluble dyes,
There are cationic dyes, etc. Note that the colorant layer for synthetic resins is similar to oil-soluble dyes and can be used.

The above-described dye is transferred in a gaseous state to the active film layer by heating and is dyed therein. The heating conditions are such that an ink containing the dye is used and the temperature is such that the dye is thermally transferred into the micropores.

Although this differs depending on the type of dye, it may be heated, for example, at 100° C. to 250° C. for several seconds to 600 seconds.

For the overcoat layer, a hard and transparent resin such as acrylic, melamine, epoxy, silicone polymer, polyimide, etc. is applied onto the micropores of the active film layer, and then heated at a temperature that hardens the resin. formed by In addition, it can also be formed by coating and heating an inorganic material such as sodium silicate or lithium silicate. The overcoat layer thus obtained prevents re-vaporization of dye molecules trapped in the micropores of the active membrane layer, prevents contamination with unnecessary substances, and improves surface smoothness. It is useful for

A feature of the present invention is that the above-described heating is performed under a reduced pressure atmosphere. The specific conditions vary depending on the type of dye used, the thickness of the metal mask, etc. When the pressure is reduced, the vaporization start temperature of the dye decreases, but it is difficult to find any regularity therein, so it is necessary to set specific reduced pressure conditions for each dye. For example, the film thickness is 0.
When using a 0.5m metal mask and a dye with a vaporization start temperature of 250°C, no dyeing will occur even if heated at 180°C for 1 minute under normal pressure, but if the atmosphere is reduced to 1 torr, the heating temperature and heating time will change. Even if the values are the same, a fine staining pattern with sufficient staining density can be obtained.

〔effect〕

Since the method for manufacturing a color filter with high physical properties and high precision according to the present invention performs heating under a reduced pressure atmosphere, the following effects can be obtained. That is, since there is no effect such as air resistance, the dye molecules can be sufficiently dispersed. Therefore, since processing can be performed with less energy, distortion due to expansion of the metal mask is reduced, dimensional reproducibility is increased, and a highly accurate color filter having a uniform and uniform dyeing pattern can be obtained. In addition, since the vaporization temperature of dye molecules is lowered, the range of dye selection is expanded, and dyes with excellent dyeability and thermal stability can be used (for example, dyes with a melting temperature of 200°C or higher and vaporization High-temperature vaporizable dyes with excellent physical properties that have a temperature of 250°C or higher can be used at 180°C or lower.) Furthermore, in a normal pressure atmosphere, impurities that are easily adsorbed to the active film layer are vaporized, so that the transparency of the active film layer is improved. Therefore, a color filter with high physical properties can be obtained. Since the influence of the metal mask thickness is small, it is possible to use a thick metal mask, and it is possible to provide durability.

〔Example〕

Examples of the present invention will be described below.

Example 1 Alumina sol-2O0 (manufactured by Nissan Chemical Co., Ltd.) was spray coated on one side of a transparent glass plate that had been washed with alkali, and heated at 70°C.
After drying for 5 minutes at 550° C., it was fired for 45 minutes, thereby obtaining an active film layer on the glass plate with an N thickness of about 2 μm.

On the other hand, three types of screen inks were obtained by mixing the following ingredients using a three roll mill.

■Red ink ethyl cellulose N-7 (manufactured by Vercules) 15 parts (
Weight parts) Ethyl cellulose N-22 (Percules'yA) 5
Part Watasorin Renodo YP (manufactured by RCR) 8 parts Butyl Cellsolve 22 parts Butyl Cellsolve Acetate 20 parts Tsurupetz 150
30 parts Green ink Ethyl cellulose N-7 (manufactured by Vercules) 15 parts (
(parts by weight) Ethyl cellulose N-22 (manufactured by Vercules) 5 parts Orezur Fast Yellow 5G (manufactured by Taoka Chemical) 6 parts Miketone Polyester Green G (manufactured by Mitsui Toatsu) 4 parts Butyl cellosolve 20 parts Butyl cellosolve Acetate 20 parts Trubec 150
30 parts Blue ink Ethyl cellulose N-7 (manufactured by Vercules) 15 parts (
(parts by weight) Ethyl cellulose N22 (manufactured by Vercules) 5 parts Kayalon Polyester Blue TS (manufactured by Nippon Kayaku Co., Ltd.) 10 parts Butyl Cellusolve 20 parts Butyl Cellusolve Acetate 20 parts Trubec 150
30 copies Screen printed on each sheet using the above screen ink, red,
Green and blue transfer sheets were obtained.

In addition, on the other hand, a thickness of 0 with a predetermined tonneau I/pattern hole
．． Three stainless steel metal masks with 03 fins were manufactured.

Next, the glass plate manufactured by the above method was preheated to 180°C, a metal mask for blue ink was placed on a predetermined position on the glass plate, and a transfer sheet printed with blue ink was placed on top of the metal mask. was placed so that its printed surface was in contact with the metal mask, and the hardness was 180 with a JIS hardness of 50 under l torr conditions.
Heat and pressure was applied for 1 minute using silicone rubber heated to °C.

After that, when the transfer sheet and metal mask are removed,
A blue dot pattern corresponding to the dot pattern on the metal mask was transferred.

Next, on the glass plate on which the blue dot pattern obtained in the above step was formed, a metal mask for green ink was placed at a predetermined position different from the blue dot pattern, and then A transfer sheet printed with green ink! 32 to 50 tor in the same manner as above.
A green dot pattern was transferred by heating and pressing at 180° C. for 40 seconds under r conditions.

Next, using a metal mask for red ink and a transfer sheet printed with red ink, 10
A red dot pattern was transferred by heating and pressing at 180° C. for 30 seconds under 0 torr conditions.

On the glass plate onto which the three primary color dot patterns have been transferred, an overcoat agent melamine resin consisting of the following composition is applied.
It was coated with 5 parts acrylic resin, 10 parts, and 85 parts water, and was subjected to dry heat treatment at 180°C for 15 minutes.

By doing this, a color filter in which a dot pattern of three primary colors was formed was obtained.

Comparative Example For comparison, the treatment was carried out under the same conditions as in the above-mentioned Examples, except that the heating was carried out under normal pressure. As a result, each color was not dyed at all. Therefore, we conducted an experiment with stricter heating conditions, and found that blue dyeing was possible at 250°C for 120 seconds, green dyeing was 250°C for 90 seconds, and red dyeing was possible at 250°C for 60 seconds. A color filter on which a pattern was formed was obtained.

Table 1 shows the physical properties and precision of the color filters obtained in the Examples and Comparative Examples described above.

Table 1: [-1] As is clear from Table 1, the color filters obtained in Examples have excellent transparency.

In the case of the comparative example, since the color filter is obtained under high heat conditions, impurities such as gas generated from the ink layer and transfer sheet during transfer dyeing are adsorbed to the active film layer, which reduces transparency. This is thought to have been inhibited.

Furthermore, the effective area in the color characteristics of one dyed dot pattern in the case of the example is 415 times that of the comparative example, and the dimensional distortion error of the four corners in the case of the effective area 60 x 60 m color filter is 7 /6 times.

Claims (1)

[Claims] (1) A step of forming an active film layer made of at least one of activated alumina or activated silica on a transparent substrate, placing a metal mask having a predetermined pattern of holes on the active film layer, and adding a sublimation layer on top of the active film layer. a step of placing a transfer sheet having an ink layer containing a dye or/and a dye that can be thermally melted and vaporized;
The steps of transferring the dye in the ink layer in a gaseous state to the active film layer by heating and dyeing it, and then removing the transfer sheet and metal mask are repeated according to the number of colors required. By this, a pattern corresponding to the pattern holes of the metal mask is sequentially formed on the active film layer, and finally an overcoat layer is provided to seal the upper part of the fine pores of the active film layer, thereby manufacturing a color filter. A method for producing a color filter with high physical properties and high precision, characterized in that the heating is performed under a reduced pressure atmosphere.