JPH07333596A - Color filter manufacturing method - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing a color filter having a good smoothness of the filter surface. [Structure] A transparent colored layer 2R, 2G, 2B of three colors of red, green, and blue is formed in a pattern on a transparent substrate 1 for coloring the transmitted light of this pixel region for each color, and the transparent coloring is performed. The ultraviolet curable resin layer 3 is provided on the entire surface including the layer, and then the portion 3a corresponding to the inter-pixel portion of the ultraviolet curable resin layer 3 is selectively exposed to light, followed by heat treatment to obtain a surface unevenness difference. Is contracted and smoothed.

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 color liquid crystal display device or the like, and more particularly to a method for manufacturing a color filter having a good surface smoothness.

[0002]

2. Description of the Related Art In a liquid crystal display device, a liquid crystal material is sealed between a front substrate and a rear substrate, and a voltage is applied to a transparent electrode provided on each of the front substrate and the rear substrate to drive the liquid crystal substance. It is a display device that displays a screen by controlling transmission / non-transmission of light rays. When performing color display with this liquid crystal display device, a color filter for coloring the transmitted light into each color is applied as the front substrate or the rear substrate.

A color filter of this type generally has a structure as shown in FIG. That is, in FIG. 1, reference numeral 1 denotes a transparent substrate such as a glass substrate, and a transparent colored layer 2 is provided in a pattern on pixel portions on the transparent substrate 1. The transparent coloring layer 2 is for coloring the transmitted light passing through the pixel portion for each color, and is generally the three primary colors of light: red, green and blue (depending on the purpose, red, green and blue may be complementary colors). ) Three-color transparent colored layers 2R, 2
G and 2B are provided for each pixel.

Although not shown, the transmitted light from between pixels (inter-pixel portion) becomes disturbance light, which lowers the contrast of the screen. Therefore, the disturbance light is blocked at the inter-pixel portion. A light-shielding portion (generally formed of a metal chrome thin film or a black pigment-dispersed resin layer) is provided.

When the color filter is applied to the front substrate or the rear substrate of the liquid crystal display device,
In order to make the gap between the front substrate and the rear substrate uniform over the entire surface and stabilize the driving of the liquid crystal material, the smoothness of the color filter surface is required.

By the way, the formation of the transparent colored layer 2 is well known by a photolithography method such as a dyeing method or a pigment dispersion method, a printing method, an electrodeposition method (in FIG. 1, the transparent coloring by the printing method is used. The case where the layer 2 is formed is shown.). For example, in the case of the dyeing method, a photosensitive resin solution is applied on a transparent substrate, and then a predetermined pattern is baked by a mask exposure method and developed to form a relief pattern, which is dyed with a dye of a desired color. Dyeing, and after that, post-treatment such as washing with water, fixing and fixing is performed. This process is repeated for each color. Further, in the case of the pigment dispersion method, instead of dyeing after development, a photosensitive resin containing a pigment of a desired color in advance is used. In the case of the printing method, a printing ink in which a color pigment is dispersed is printed on the pixel portion in a pattern to form the ink. Further, in the case of the electrodeposition method, a colored electrodeposition resin is electrodeposited in a pixel pattern.

[0007]

Among the above methods for forming a transparent colored layer, the printing method is particularly advantageous in terms of process simplification and cost, but like other methods, the surface of the formed transparent colored layer is the same. Is not good in smoothness. As a means for improving the smoothness, for example, there is a method of overcoating with a transparent resin after forming the transparent colored layer, but in reality, the uneven shape of the surface after forming the transparent colored layer also affects the surface of the overcoat layer. It remains as it is and does not improve the smoothness so much. There is also a method of polishing the entire surface of the filter,
Since not only the convex portions but also the concave portions are polished, the uneven shape after the formation of the transparent colored layer remains as in the above case. for that reason,
Conventionally, a method of performing the overcoating process twice or alternately repeating overcoating and polishing several times has been carried out. However, the process is complicated and a great effect of improving smoothness can be obtained. There wasn't.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a method of manufacturing a color filter having good smoothness of the filter surface.

[0009]

In order to achieve the above object, a method of manufacturing a color filter according to the present invention comprises a transparent colored layer for coloring transmitted light of the pixel portion for each color on a pixel portion on a transparent substrate. Forming in a pattern, providing an ultraviolet curable resin layer on the entire surface including the transparent colored layer, and then selectively exposing a portion of the ultraviolet curable resin layer corresponding to an inter-pixel portion, followed by heat treatment. Is characterized by.

Further, the method for manufacturing a color filter of the present invention is characterized in that a light-shielding portion for blocking light transmission from this portion is formed at a portion between pixels on the transparent substrate.

[0011]

According to the present invention, the ultraviolet curable resin layer is provided on the entire surface including the transparent colored layer formed on the transparent substrate, and then the portion corresponding to the inter-pixel portion of the ultraviolet curable resin layer is selectively exposed. Then, heat treatment is performed. The above-mentioned UV-curable resin layer has a difference in thermal shrinkage between a portion cured by exposure and a portion not cured (a portion which is not cured due to unexposed) in the subsequent heat treatment, and the unexposed portion is more than the exposed portion. Large heat shrinkage. Therefore, since the portion corresponding to the pixel portion (convex portion) of the ultraviolet curable resin layer is unexposed, heat shrinkage occurs more than the portion corresponding to the exposed inter-pixel portion (concave portion). The rate is high and as a result,
The difference between the convex portion and the concave portion on the surface of the ultraviolet curable resin layer is reduced, and the surface smoothness is improved.

[0012]

The present invention will be described in detail below with reference to examples.

As described above, FIG. 1 shows a state in which three transparent colored layers 2R, 2G and 2B of red, green and blue are formed in a pixel pattern on a transparent substrate 1 such as a glass substrate by a printing method. Is shown. The three colored transparent colored layers 2R, 2G, and 2B can be formed by the above-mentioned dyeing method, pigment dispersion method (above photolithography method), or electrodeposition method in addition to the printing method. As described above, the printing method is used in this embodiment because it is advantageous in terms of process simplicity and cost.

In the case of the printing method, the transparent colored layer is formed by printing in a pixel pattern with a printing ink in which a color pigment is dispersed.

The printing ink used comprises a resin binder, a transparent coloring pigment, a solvent, additives (surfactant, dispersant, coupling agent, etc.) as main components, and the transparent coloring pigment is added to 100 parts by weight of the resin binder. For 1 to 100
Parts by weight, solvents and additives are each added in an appropriate amount, and examples of the resin binder include acrylic resins, epoxy resins, polyester resins, polystyrene resins, polyimide resins, melamine resins, and mixtures of these resins. Used.

The plate type is a screen printing method, a relief printing method,
It is a lithographic printing method, an intaglio printing method, an intaglio offset printing method, etc., and after printing on the transparent substrate 1, drying and precure treatment (for example, 50 to 100 ° C., 10 to 60 minutes) are performed, and then heat hardening treatment (for example, 150-250 ° C, 10-60
Minutes).

More specifically, for example, the red ink is supplied onto the printing plate (the intaglio plate for the red pixel pattern), the ink is made uniform with a squeegee, and the excess ink is scraped off with a doctor. Then, the plate cylinder blanket is brought into contact with the surface of the printing plate while rotating, and the ink pattern is transferred from the printing plate to the plate cylinder blanket. Further, the plate cylinder blanket is brought into rotary contact with the transparent substrate 1, and the ink pattern is transferred from the plate cylinder blanket onto the transparent substrate 1 to form a red pixel pattern (transparent colored layer). Similarly, green and blue pixel patterns are formed.

Thus, the transparent colored layers 2R, 2G, 2 of three colors of red, green and blue are printed on the transparent substrate 1 by the printing method.
B is formed in a pixel pattern. The arrangement of the pixel patterns is not particularly limited, and may be stripes, deltas, mosaics, or the like.

Although not shown, as described above, a light-shielding portion for blocking the transmitted light from the inter-pixel portion can be formed on the transparent substrate 1 so as not to reduce the contrast of the screen. . The light shielding portion is generally provided in a pattern with a metal chromium thin film or a black pigment dispersed resin layer.

Then, an ultraviolet curable resin layer 3 is formed on the entire surface including the transparent colored layer, and the state shown in FIG. 2 is obtained.

The UV-curable resin used in the present invention is a transparent resin which is made UV-curable by containing a photoinitiator based on, for example, an acrylic resin, an epoxy resin, a polyimide resin or the like. (Eg 250 ° C)
It is preferable that the visible light transmittance is 95% or more even if the above is performed. Examples of commercially available products include TLC-2000, 2500, 2600, 2650 mainly composed of epoxy resin.
(Product name) (manufactured by Okuno Chemical Industries Co., Ltd.).

The ultraviolet curable resin layer 3 is applied and formed by a spin coating method, a roll coating method, a bar coating method, a printing method or the like. The coating thickness of the ultraviolet curable resin layer 3 is appropriately in the range of about 1.0 to 2.0 μm.

As can be seen from FIG. 2, the concavo-convex shape on the surface after the formation of the transparent colored layer remains on the surface of the ultraviolet curable resin layer 3 as it is, and the smoothness is not good as it is.

Next, as shown in FIG. 3, a contact method or a proximity method (a gap of about 200 μm or less is provided to prevent dust from adhering to the mask through a photomask 4 on which a predetermined pattern is formed. ), For example, by irradiating with an ultraviolet ray at an exposure amount of ^{20 to} 1000 mJ / cm ² , the portion 3 a corresponding to the inter-pixel portion of the ultraviolet curable resin layer 3 is selectively exposed.

Then, heat treatment is subsequently performed. This heat treatment is performed using a hot oven or the like at a temperature of 150 to 250 ° C. for about 30 to 120 minutes. The UV-curable resin layer 3 has a difference in thermal shrinkage between a portion cured by exposure and a portion not cured (a portion which is not cured due to unexposed) in the subsequent heat treatment, and the unexposed portion is more exposed than the exposed portion. Also has a large heat shrinkage rate. That is, since the portion 3b corresponding to the pixel portion of the ultraviolet curable resin layer 3 is unexposed, the heat shrinkage rate is larger than that of the portion 3a corresponding to the exposed inter-pixel portion. As a result, as shown in FIG. In addition, the difference between the convex portion and the concave portion on the surface of the ultraviolet curable resin layer 3 is reduced, and the surface smoothness is improved.

For example, a concrete example will be described. As the UV curable resin, the above-mentioned commercial product TLC-2650 was used, and this was applied to a thickness of 1.0 μm to form a photomask with an exposure dose of 50 mJ / cm ^2. When selectively exposed to ultraviolet light through, and then heat-treated at 200 ° C. for 60 minutes, the portion cured by exposure shrinks to 85 to 95% and the portion not cured due to unexposed shrinks to 60 to 70%. . For example, when there is a difference of about 1.5 μm in the surface of the ultraviolet curable resin layer 3 before the exposure and heat treatment, the difference between the unevenness becomes 1.0 μm or less by the exposure and the heat treatment. Further, when the above-mentioned light-shielding portion is formed of a black pigment-dispersed resin layer having a thickness of 1.2 to 1.5 μm and the transparent colored layer is formed, the difference in surface irregularities is about 1.0 μm. By exposing and heat-treating the ultraviolet curable resin layer 3, the unevenness difference is reduced to 0.
It is smoothed to about 5 μm or less.

[0027]

As described in detail above, according to the method of manufacturing a color filter of the present invention, an ultraviolet curable resin layer is provided on the entire surface including a transparent colored layer formed on a transparent substrate, and then the ultraviolet curable resin is cured. By selectively exposing a portion corresponding to the inter-pixel portion of the resinous resin layer and then performing a heat treatment, the ultraviolet-curable resin layer has a portion cured by exposure and a portion not cured by exposure (cured because it is not exposed. The difference in the thermal contraction rate between the non-exposed area and the exposed area is larger than that in the exposed area. Is not exposed to light, the heat shrinkage rate is larger than that of a portion corresponding to the exposed inter-pixel portion (which is a concave portion). The difference with the recess is reduced It demonstrates an excellent effect of smoothness of the surface is improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a color filter in which three color transparent colored layers are formed on a transparent substrate.

FIG. 2 is a schematic cross-sectional view showing a state where an ultraviolet curable resin layer is formed on a transparent colored layer.

FIG. 3 is a schematic cross-sectional view showing a state where a portion corresponding to a portion between pixels of the ultraviolet curable resin layer is selectively exposed.

FIG. 4 is a schematic cross-sectional view showing a state where a surface is smoothed by performing heat treatment after exposure.

[Explanation of symbols]

 1 Transparent Substrate 2 Transparent Colored Layer 2R Red Transparent Colored Layer 2G Green Transparent Colored Layer 2B Blue Transparent Colored Layer 3 UV Curable Resin Layer 3a Irradiated Part 3b Unirradiated Part 4 Photomask

Claims (2)

[Claims] 1. A transparent coloring layer for coloring the transmitted light of each pixel portion for each color is formed in a pattern on a pixel portion on a transparent substrate, and an ultraviolet curable resin layer is provided on the entire surface including the transparent coloring layer, Next, a method for producing a color filter, which comprises selectively exposing a portion of the ultraviolet curable resin layer corresponding to an inter-pixel portion, and subsequently performing heat treatment. 2. The method of manufacturing a color filter according to claim 1, wherein a light-shielding portion that blocks light transmission from the transparent substrate is formed at a portion between pixels on the transparent substrate.