JPH08106005A - Production of color filter - Google Patents

Abstract

PURPOSE: To reduce processes by simplifying a flow process for leveling and a next hardening process and to increase the uniformity of film thickness by decreasing the ruggedness of the surface. CONSTITUTION: This producing method of a color filter is provided with a 1st process for patterning a divided pattern 14 forming an almost closed internal region in a plane on one flat surface of a substrate 10, a 2nd process for forming a color pattern 16 with an ink composed of a mixed solution containing at least a thermoplastic resin solution, a catalyst and a coloring agent for coloring on the part of the internal region 12 surrounded by the divided pattern 14 on one surface of the substrate 10, a 1st heating process for leveling the ink for forming the color pattern 16 by heating to let flow and a 2nd heating process for hardening the ink by heating further after the 1st heating process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter used in a liquid crystal display, an image pickup device or the like, and more specifically, a flat surface of a substrate is patterned with a partition pattern such as a black stripe or a black matrix. After that, the present invention relates to a technique that can be effectively used for forming a highly flat color pattern by printing or the like in the portion of the internal region surrounded by this partition pattern.

[0002]

BACKGROUND OF THE INVENTION Conventionally, as a method of manufacturing a color filter, a method using a photolithography technique and a method using a printing technique are known. However, each of them has advantages and disadvantages. The former has excellent pattern dimensional accuracy and color purity, but has a large number of steps,
Moreover, since the material is expensive, the cost is high and it is difficult to increase the screen size. The latter is advantageous in terms of cost and large screen, but has drawbacks in each of the dimensional accuracy of the pattern, the uniformity of the film thickness, and the surface condition, which makes the image quality uneasy.

On the other hand, there is also known a method in which the advantages of each of them are utilized by combining the techniques of photolithography and printing. For example, a partition pattern such as a black stripe or a black matrix for partitioning a pixel region is formed on a transparent substrate by a photolithography technique, and an internal region surrounded by the partition pattern, that is, a portion of the pixel region is printed by a printing technique. It forms a color pattern. According to this method, a highly accurate division pattern having excellent surface accuracy and dimensional accuracy can be obtained, and accordingly, dimensional accuracy of the color pattern can be also obtained, and the cost and cost which are advantages of the printing technology can be obtained. It can be advantageously developed in terms of large screen. However, on the other hand, since it is difficult to obtain a good surface condition by the printing method, unevenness is likely to occur on the surface. Therefore, it is necessary to take measures to further improve the uniformity of the color pattern film thickness.

Therefore, in recent years, a leveling technique has been developed to flatten the surface of the color pattern and make the film thickness uniform. This is, for example, in JP-A-4-14.
As shown in Japanese Patent No. 3703, a substrate having a partition pattern such as a black stripe or a black matrix is printed with a color ink in an internal region surrounded by the partition pattern, and the flow characteristics of the constituent material of the ink itself are used. Then, after being diffused in the region, the ink material is cured. Here, when the color ink material for utilizing the flow characteristics is a photocurable material or an ultraviolet curable UV ink, the leveling is performed by allowing the color ink material to stand for a certain period of time after printing and allowing it to flow naturally.
Further, in the case of a thermoplastic ink material, the leveling is performed by actively heating, melting and flowing.

According to another technique disclosed in Japanese Patent Laid-Open No. 2-7001, a partition pattern having a relatively large film thickness having a barrier function is formed on a flat surface of a substrate by a photolithography technique, and the partition pattern is formed. In the portion of the inner region surrounded by the pattern, a partial pattern slightly smaller than the size of the inner region is formed by the fluid pattern material, and the peripheral portion is leveled by leveling the partial pattern. It is designed to be in contact with the inner surface. In this case, as a fluid pattern material, a colorant is mixed with a thermosetting resin material such as polyamide or polyimide, and further diluted with a solvent having a low surface tension to obtain a fluid solution having a low viscosity. It is used and leveled by natural flow.

[0006]

The present inventor is interested in a technique of combining both techniques of photolithography and printing, in which the leveling is performed to flatten the surface of the color pattern and make the film thickness uniform. , Variously examined. As a result, the following was found. In the technique described in JP-A-4-143703 mentioned above, in the method of causing natural flow using UV ink or the like, leveling is performed by mere natural flow utilizing the fluidity of the ink itself immediately after printing before solidification. Since this is a method, it takes time to perform leveling, and there is a problem in that leveling is not sufficiently performed when the surface tension of the ink is high or the viscosity of the ink is high. Although it is possible to reduce the viscosity by using a large amount of a solvent, when a large amount of the solvent is included, curing by ultraviolet irradiation may not be sufficiently performed, and it takes time even if the curing is performed. Conversely, the adverse effect of the solvent causes a problem that the excellent characteristics of the UV ink are impaired.

On the other hand, the method using a thermoplastic ink has an advantage that a pattern having a high flatness can be obtained relatively easily because the ink is fluidized and leveled by being positively heated and melted. On the other hand, on the other hand, since it is made to flow by heating, it takes time to cool it for curing, and during that time, the substrate itself cannot be moved in the manufacturing line until the ink is at least semi-cured, thus shortening the process. There is a problem that it is difficult to plan. Although a method of forced cooling can be considered as a means for solving this point, it is not preferable because the color pattern itself may be distorted or have fine cracks because of rapid cooling. Further, in this method, since it is necessary to move the substrate from the heating process to the cooling process in the manufacturing line, there is a problem that the leveling state of the ink obtained by flowing by heating changes when the substrate is moved.

On the other hand, in the technique disclosed in Japanese Unexamined Patent Publication No. Hei 2-7001, a thermosetting resin material mixed with a colorant is diluted with a solvent to form a low-viscosity solution as a fluid pattern material. Therefore, although it is possible to obtain sufficient fluidity, it is necessary to move the substrate itself to the heating process in order to heat-cure it. There is a problem that the problem of occurs. In addition, especially in the case of a pattern material containing a polyimide resin as a main component, it is difficult to dry, so that it takes a long time to cure. When a color pattern is formed in the inner area surrounded by the partition pattern by a printing method, even if the ink of the color pattern once adheres to the inner surface of the partition pattern, the partition pattern itself has a property of repelling ink slightly. In some cases, the ink itself is pushed back to the center of the inner area, and the center of the surface swells to form a lumpy shape, which is one of the causes of poor pattern flatness.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned examination results, and simplifies the flow process for leveling and the subsequent curing process to shorten the process,
Moreover, it is an object of the present invention to provide a method for manufacturing a color filter that can reduce unevenness on the surface and enhance the uniformity of film thickness.

[0010]

According to the present invention, there is provided a first step of patterning a partition pattern for forming a planarly closed internal region on a flat surface of a substrate, and a partition pattern on the one surface of the substrate. A second step of forming a color pattern using an ink composed of a mixed solution containing at least a thermoplastic resin solution, a thermosetting catalyst, and a coloring agent for coloring in a portion of an inner region surrounded by the color pattern; A first heating step of leveling the ink to be formed by heating and fluidizing it is provided, and a second heating step of further heating the ink to heat-cure the ink after the first heating step.

As the ink for forming the color pattern, there is used an ink composed of a mixed liquid having a characteristic that it can be melted and flowed by heating and can be cured by further heating. For example, a thermosetting catalyst and a colorant are added to an acrylic thermoplastic resin solution, and the viscosity required for the ink is adjusted by the amount of the solvent. When heated above the temperature, the thermosetting catalyst works and has the property of being thermoset. This characteristic is a characteristic that it flows only in a so-called heating temperature atmosphere and then cures. Therefore, by utilizing this characteristic, both the step of flowing and leveling the ink and the step of curing are performed only by the heating step. Is done by.

Here, the heating temperature in the second heating step is set higher than the heating temperature in the first heating step. In that case, the first heating step is performed under an atmosphere of a heating temperature necessary for the second heating step, particularly at a temperature required for the second heating step, but close to a temperature range required for the first heating step. By performing at the temperature, the first heating step and the second heating step may be performed at the same time.

[0013]

The color pattern formed in the inner region surrounded by the partition pattern is leveled by being fluidized in the first heating step. This leveling is performed by melting and fluidizing the thermoplastic resin, which is the main component of the ink material, so that a higher leveling action occurs than the natural flow of the ink itself, which improves the flatness. To do. Then, by the second heating step,
The thermosetting catalyst works and the ink is thermoset in the leveled state, whereby a highly flat color pattern is obtained.
Since the first heating step for leveling and the second heating step for curing are both heating steps, they can be performed without moving the substrate itself during the steps from leveling to curing. Therefore, the ink obtained by flowing by heating can be cured while maintaining a good leveling state.

When the heating temperature in the second heating step is higher than the heating temperature in the first heating step, the curing time of the ink is shortened accordingly, but the first heating step is Two
By performing the heating step in the heating temperature atmosphere required in step 1, both the leveling step and the curing step can be performed in a single heating step. In such a case, both the time required for leveling and the time required for curing can be shortened. From these, a color filter having a color pattern with a more uniform film thickness, which has a simple process, good productivity, a good surface condition, and the like can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a process of a color filter manufacturing method to which the invention is applied. First, FIG. 1A
As shown in FIG.
A glass substrate 10 having the above is prepared, and a black polyimide resin layer 20 is formed on one surface 10a of the glass substrate 10 using a black polyimide resin material mixed with carbon black, for example. The layer 20 has a thickness of, for example, 1 to 4 m in this embodiment.
It is set to a value that is relatively thick and causes the barrier function described later. A method such as spin coating, roll coating, or printing can be applied to form the layer 20, but leveling may be added to obtain a coating layer as uniform as possible. Then, the layer 20 is patterned by a well-known photography technique, and as shown in FIG. 1B, a matrix-shaped partition pattern (light-shielding pattern) 14 is formed.
To form. The partition pattern 14 is closed when seen in a plan view, and has a square inner region 12, for example, formed therein.

After the patterning, the partition pattern 14 is heat-treated to provide sufficient solvent resistance. Further, if necessary, the partition pattern 14 is subjected to a surface treatment for enhancing the affinity with the ink forming the color pattern described later. As the surface treatment for increasing the affinity, for example, a so-called corona treatment known as surface ion treatment by corona discharge, or a surface treatment method such as a treatment with a silane coupling agent can be used. The partition pattern 14 thus obtained has high dimensional accuracy because it is based on the photolithography technique.

Next, the internal region 1 surrounded by the partition pattern 14
The color pattern 16 is formed on the second portion by, for example, screen printing using an ink made of a mixed liquid containing a thermoplastic resin, a thermosetting catalyst, a colorant, and a solvent. When forming the color pattern 16, the ease of printing,
In consideration of the subsequent leveling, as shown in FIG. 1C, a certain amount of ink is printed so that a partial pattern 16a smaller than the internal region 12 is formed in the internal region 12. The partial pattern 16a for forming the color pattern 16 is performed for each color corresponding to the three primary colors of red, green and blue.

As the ink material for the color pattern 16, an ink composed of a mixed liquid having a characteristic that it can be melted and flowed by heating and then cured by heating is used. For example, a thermosetting catalyst and a colorant are added to an acrylic thermoplastic resin solution to adjust the viscosity required for the ink by the amount of solvent, and those that are in a fluidized state by heating have a certain temperature or higher. When heated, a thermosetting catalyst works and has the property of being thermoset.

In this embodiment, as the resin material, an acrylic resin known as a thermosetting overcoat material, in which a thermosetting catalyst is added to a thermoplastic resin (TOC Co., Ltd., trade name: MOC-001), is used. Was used, and a dye as a colorant and diethylene glycol dimethyl ether as a solvent were added thereto to prepare a mixed solution to be a color ink. Three types of mixed liquids for the color inks, red, green and blue, are prepared. For example, in the case of red ink, the acrylic resin (MOC-001) 120.0 26.8 parts by weight of red dye, based on parts by weight (solid content 70 wt%),
The solvent was 30.0 parts by weight. In the case of green ink,
29.4 parts by weight of the green dye and 30.0 parts by weight of the solvent were used with respect to 120.0 parts by weight of the acrylic resin (MOC-001) (solid content 70 wt%). In the case of blue ink, 14 parts by weight of blue dye and 30.0 parts by weight of solvent were used with respect to 120.0 parts by weight of acrylic resin (MOC-001) (solid content 70 wt%). In addition, an appropriate amount of an adhesive agent such as a silane coupling agent for enhancing the adhesiveness between the substrate and the color pixels was added to each color ink.

The thermosetting overcoat material (MOC-001) itself has a property of being thermally cured after being melted by heating, and therefore it is usually cured in an atmosphere at a heating temperature of about 150 ° C. or higher. is there. As the dye for coloring, various types of dyes such as azo, anthraquinone, phthalocyanine, carbonium, quinone itomine, methine, benzoquinone and naphthoquinone can be used. Each dye may be used alone or in combination of a few dyes for each color pattern. Further, as the colorant, various pigments can be used in addition to the above dyes. As for the solvent, those capable of dissolving colorants such as dyes,
Besides diethylene glycol dimethyl ether, for example, methyl cellosolve and ethyl cellosolve can be used.

As a method of forming the partial pattern 16a, another printing method or a printing method such as an ink jet method can be applied. According to these printing methods or their equivalents, the ink necessary for obtaining the pattern can be directly deposited on the substrate without a troublesome process such as photolithography.

After the partial pattern 16a is formed in this manner, the partial pattern 16a is then removed by, for example, 1
By heating at a temperature of 50 ° C. or higher to melt the ink forming the partial pattern 16a and bring it into a fluid state, FIG.
Level as shown in. Then, by further continuing the heating step, the thermosetting catalyst contained in the ink works to cause thermosetting. As a result, the surface is leveled and the surface is flattened, and in this state, the color pattern 16 having a uniform film thickness is obtained. Here, in this heating step, a clean open method, a method using a hot plate, a method of heating in a heating temperature atmosphere in a heating chamber, or the like is adopted.

FIG. 1D shows a state where the leveling is completed and the layer is hardened. As can be seen from this, at the time of leveling, the partition pattern 14 functions as a barrier that prevents the partial pattern 16a from spreading. Therefore, the amount of ink in the partial pattern 16a is determined by the amount of ink in the partition pattern 1 after leveling.
4 and the flattened partial pattern are preferably set to have substantially the same height. Each color pattern 1 obtained in this way
6 contacts the inner surface of the partition pattern 14, and therefore
The dimensional accuracy is the same as that of the partition pattern 14.

According to the inks of the formulations of the examples, the curing starts with less leveling at 150 ° C. or lower, but by heating to 150 ° C. or higher, the reaction of leveling → curing gradually occurs. occured. Therefore,
In this formulation example, heating to 150 ° C. or higher, preferably 1
It is desirable to heat at 80 ° C. or higher, more preferably 200 ° C. or higher. In addition, in the heating step during leveling, when heating is performed at a temperature of 150 ° C. or higher, leveling and curing can be performed.
The leveling step and the curing step can be performed at the same time under the same temperature atmosphere of about 0 ° C. In addition, when the leveling time and the curing time are shortened, the heating temperature may be set high. When heating at a high temperature of 200 ° C. or higher, the curing time can be particularly shortened, but it is preferable to determine the heating temperature in consideration of the time required for leveling and the heat resistance of the colorant. Curing time: clean open, 150 ° C for about 1 hour, 180 ° C for 30 minutes, 200
It was about 10 minutes at ° C.

[0025]

According to the present invention, when a color pattern is formed in a portion of an inner region surrounded by a partition pattern, a mixed solution containing at least a thermoplastic resin solution, a thermosetting catalyst, and a coloring agent for coloring is used. A color pattern is formed by using the ink, and the color pattern is formed by utilizing the characteristic that it melts and flows in a heating temperature atmosphere and is cured in the heating temperature atmosphere. That is, the ink used in the present invention has a property that it is in a fluid state by heating, but when it is heated to a certain temperature or more, the thermosetting catalyst works and heat cures. This characteristic is
Since it has the property of flowing only in a so-called heating temperature atmosphere and then hardening, by utilizing this property, both the steps of flowing and leveling the ink and hardening can be performed only by the heating step. it can. Therefore, the manufacturing process can be simplified as compared with the conventional color filter manufacturing process, and the productivity can be improved accordingly.

Moreover, the leveling of the ink is performed by melting and fluidizing the thermoplastic resin which is the main component of the ink material, so that a leveling action higher than the natural flow of the ink itself occurs. Thus, a color pattern with high flatness can be obtained. In addition, a first heating step for leveling and a second heating step for curing
Since both heating steps are heating steps, they can be performed without moving the substrate itself during the steps from leveling to curing. Therefore, the ink obtained by flowing by heating can be cured while maintaining a good leveling state.

If the heating temperature in the second heating step is set higher than the heating temperature in the first heating step, the curing time of the ink can be shortened accordingly, but the first heating By performing the process in the atmosphere of the heating temperature required in the second heating process, both the leveling process and the curing process can be performed in one heating process. In this way, both the time required for leveling and the time required for curing can be shortened. From the above, it is possible to provide a method for manufacturing a color filter having a simple process, good productivity, a good surface condition, and a color pattern with a more uniform film thickness.

[Brief description of drawings]

FIG. 1 is a sectional view showing an outline of a process according to the present invention.

[Explanation of symbols]

 10 Substrate 12 Internal Area 14 Partition Pattern 16 Color Pattern 16a Partial Pattern

Claims (6)

[Claims] 1. A method of manufacturing a color filter, comprising: a flat pattern on a flat surface of a substrate; a partition pattern forming a substantially closed inner region in a plane; and a color pattern occupying a portion of the inner region surrounded by the partition pattern. Then, next (A) ~
A method of manufacturing a color filter, comprising the steps (D). (A) A first step of patterning the partition pattern on one flat surface of the substrate. (B) The color pattern is formed on an inner region of the one surface of the substrate surrounded by the partition pattern using an ink composed of a mixed solution containing at least a thermoplastic resin solution, a thermosetting catalyst, and a coloring agent for coloring. Second step of forming. (C) A first heating step in which the ink forming the color pattern is heated and fluidized to be leveled. (D) A second heating step of further heating and thermosetting the ink after the first heating step. 2. The heating temperature in the second heating step is higher than the heating temperature in the first heating step,
The method for manufacturing a color filter according to claim 1. 3. The method of manufacturing a color filter according to claim 1, wherein the first heating step is performed in an atmosphere of a heating temperature required in the second heating step. 4. The method for manufacturing a color filter according to claim 3, wherein the first heating step and the second heating step are performed simultaneously. 5. The color filter according to claim 1, wherein the partition pattern is subjected to a corona treatment for giving affinity to the ink before the second step of forming the color pattern. Production method. 6. The method of manufacturing a color filter according to claim 1, wherein the second step is performed by printing or a method similar thereto.