JPH11295518A - Substrate for color filter and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rising that cannot be avoided in the conventional process by using a substrate with a recess sufficient to absorb rising at a color joining part, that is, on a light shielding resin layer in place of the substrate setting the conventional light shielding black resin layer. SOLUTION: A light shielding black resin layer 2' is formed on a glass substrate 1 in a strip shape. A photosetting resin film 8 comprising a photosetting resin layer 6 and a base film 7 is heated to about 60-80 deg.C and press-bonded to the substrate 1 with a laminator or the like so that the layer 6 comes in contact with the substrate 1 (a). Reverse exposure is then carried out by irradiation with UV 9 from the substrate side. The light shielding layer 2' acts as a light shielding mask, the photosetting resin layer in the gap part of the light shielding layer is set 6' and the part on the light shielding layer remains in the unset state 6 (b). The base film 7 is peeled and the unset part 6 is removed by development with an about 2% alkali soln. to obtain the objective transparent substrate with a light shielding layer pattern (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for a color filter used for a flat panel display such as a color liquid crystal display, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 5, a light shielding layer 2 between pixels is formed on a transparent substrate 1 made of glass, plastic, or the like.
On top of this, R, G, B and other colored layers 3 having the necessary optical characteristics as a color filter are formed in a required pattern. The colored layer is formed by various methods such as a pigment dispersion method, a dye dispersion method, an electrodeposition method, and a printing method, and the flatness and smoothness of the surface greatly affect the display characteristics of the liquid crystal cell.

However, in any of the methods, each of the colored layers R, G,
If there is no gap where light leakage occurs at the boundary between B, there is a tendency for bulges 4 to occur at the boundary junction, which is a factor that impairs flatness. In particular, when a black resin light-shielding layer (FIG. 5-b "2 '") is used instead of the conventional chromium and chromium oxide thin film (FIG. 5-a "2") for the purpose of cost reduction of the light-shielding layer, the film becomes characteristically thin. A thickness of about 1 μm is required. Therefore, the light-shielding layer becomes about 10 times as thick as the conventional one, and the bulge 4 becomes even greater (FIG. 5).
b).

In order to solve this problem, a transparent resin is applied to the entire surface of the light-shielding layer pattern to eliminate a large step (Japanese Patent Laid-Open No. 7-294723). Surface (Japanese Unexamined Patent Publication No. 7-28
A technique for flattening the substrate surface, such as 7112), has been proposed. The surface of the formed color filter is polished, and a smooth layer 5 made of a transparent resin is further formed on the color filter.
For example, means such as overcoating is used.

[0005]

As described above, in a color filter using a thick light-shielding layer such as a black resin layer formed by carbon dispersion as described above, in any of the manufacturing methods, each colored layer joint portion on the light-shielding layer is formed. There is a large tendency for bulging protrusions to occur, and there are many problems to solve this, and it is difficult to achieve a sufficient solution only by reducing the degree by various complicated measures.

Accordingly, the present invention provides a means for drastically solving these problems by using a transparent substrate having a shape for preventing the occurrence of bulges which cannot be avoided in the production method by the current method.

[0007]

In order to achieve the above object, the structure of the color filter substrate of the present invention comprises a color filter.
A transparent layer thicker than the light-shielding layer is provided in the gap between the light-shielding layer patterns on the transparent substrate so that the light-shielding layer at the boundary between the colored layers of the filter is concave. In addition, when each colored layer is formed on a transparent substrate having a light-shielding layer, a concave portion having a capacity corresponding to a bulging amount generated at a boundary portion between the colored layers or a concave portion larger than that is formed.
Further, the upper end surface of the concave portion formed by the light shielding portion pattern and the transparent resin layer provided in the gap portion is rounded.

As a method for producing a substrate having such a shape, a photocurable resin film having a photocurable transparent resin coating layer having a thickness such that the film thickness after curing becomes larger than the light-shielding layer by a required amount is used. A first step of pressing the coating film layer against the transparent substrate on which the light-shielding layer pattern is formed, a second step of irradiating light from the transparent substrate side to cure the resin layer in the gap between the light-shielding layers, and A third step of developing and removing the cured portion;
And a fourth step of fully curing this.

[0009]

Embodiments of the present invention will be described below. FIG.
A black resin light-shielding layer 2 ′ having a width of 20 μm and a thickness of 0.9 μm is formed in stripes at intervals of 90 μm on a glass substrate 1 having a size of 300 × 400 mm and a thickness of 1.1 mm. A photocurable resin film 8 and a photocurable resin layer 6 are formed on the glass substrate 1.
Then, it is pressed by using a laminator or the like in a state where it is heated to about 60 to 80 ° C. so as to be in contact with (FIG. 1A). The photocurable resin film 8 is made of a base film 7 such as polyester.
For example, a commercially available acrylic styrene-based transparent UV-curable resin layer 6 having a required coating film thickness is selected from those coated thereon.

Next, back exposure is performed by UV irradiation 9 of about 10 to 15 j / cm from the transparent substrate side. As a result, the light-shielding layer 2 'becomes a light-shielding mask, and the photocurable resin layer in the gap between the light-shielding layers is hardened 6', and the portion on the light-shielding layer remains unhardened 6 (FIG. 1-b).

Then, the base film 7 is peeled off to remove 2%
The light-shielding layer of the present invention having a transparent resin layer 6 ′ having a larger thickness than the light-shielding layer in the gap between the light-shielding layers 2 ′ is developed by removing the uncured portions 6 by developing using an alkaline solution of about A transparent substrate with a light-shielding layer pattern is obtained (FIG. 1-c).

In this case, the practical size of the concave portion, that is, the step between the transparent portion and the transparent portion may be determined according to the following conditions. First, a resin light shielding layer 2 ′ is formed on a conventional glass substrate 1.
When the R, G, and B color layers are provided on the substrate on which the pattern is formed, the actual state of the bulge amount 4 generated at the boundary between the layers is measured (FIG. 2A). Therefore, a substrate having a concave portion having a size corresponding to this amount may be formed. If the size is smaller than the swell amount, the swell remains (see FIG. 2).
b), if it is large, a dent is formed (FIG. 2-c). Therefore, the size of the concave portion that can obtain the shape (FIG. 2D) that is flat or slightly concave by exhibiting the effect of the present invention may be selected and put to practical use.

As a specific example, when the R, G, and B colors are formed to a thickness of 1.0 μm by a printing method using the substrate provided with the black resin light-shielding layer pattern of the present embodiment, the height of the swell amount is as follows. 0.45μ. Therefore, a substrate having the shape of the present invention in which the step was 0.35 μm was prepared using a photocurable resin film in which the thickness of the transparent resin became 1.25 μm after curing, and R, G, and B colors were similarly formed. A color filter having excellent flatness was obtained. This effect is shown in FIG. 3 in comparison with a conventional example using actually measured surface roughness data. The effect of improving the surface flatness of the glass substrate with a light shielding layer itself a and the color filter after formation b in the conventional method A and the present invention B is apparent.

Furthermore, chemical resistance is improved while flatness is improved.
When an overcoat layer is formed thereon as an auxiliary means for improving the spatter resistance and the like, the flattening is easier with the concave type rather than the one with some protrusions. Therefore, it is effective to select the configuration conditions of the substrate such that the surface of the boundary portion is flush or concave.

The shape of the concave portion also affects the uniformity and yield of the productivity. The state described so far has a general shape as shown in FIG. 4-a, but depending on the process conditions, a horn-shaped projection may be formed at the upper end as shown in FIG. 4-b. With such a shape, a smooth flow is inhibited at the time of forming the R, G, and B colored layers, and a desired flatness cannot be obtained even when a concave substrate is used. Therefore, it is practically effective to provide the upper end face with a rounded shape as shown in FIG. These shapes can be determined by a combination of conditions for forming the photocurable resin, that is, lamination conditions, UV exposure conditions, environmental conditions, and the like.

[0016]

As described above, the present invention fundamentally solves the problem of the flatness caused by the swelling of the junction of each color, which was a fatal problem in the process of manufacturing the color filter by various methods. Things. In this method, instead of a conventional substrate provided simply with a black resin light-shielding layer, a concave portion large enough to absorb an amount corresponding to the build-up amount generated by the conventional method is provided at the joint of each color, that is, the upper part of the resin light-shielding layer. It can be easily applied to any of the conventional methods by a very simple means using only a substrate. Here, the size and shape of the concave portion may be selected and designed according to the type, shape, manufacturing method, and the like of the color filter to be formed thereon, so as to obtain a flat surface suitable for the purpose of the present invention.

Although the effects of the present invention can be obtained by using any of the color filters manufactured by any of the methods, it is particularly remarkable in the production of a color filter having a printing method which has the highest possibility of low-cost production. Among the printing methods, a three-color simultaneous printing method for the purpose of efficient production, that is, printing each color between light-shielding layers at a fixed interval to avoid mixing of three colors of R, G, and B, and pressing the gap. The method of compensating is particularly effective for removing the adverse effect of increasing the swelling in the construction method.

As described above, according to the present invention, a color filter having excellent surface flatness can be completely eliminated since the ridges and protrusions of each color which cannot be avoided in any color filter manufacturing method can be completely eliminated. can get. Of course, only by using such a substrate, it can be easily applied to any color filter manufacturing method, so that the practical effect is large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a manufacturing method according to the present invention.

FIG. 2 is a cross-sectional view showing surface flatness due to a difference in typical conditions of the present invention.

FIG. 3 is a conventional example of a substrate with a resin light-shielding layer and a color filter using the same, and a surface roughness measurement chart in the present invention.

FIG. 4 is a cross-sectional view showing a difference between end face shapes in the present invention.

FIG. 5 is a cross-sectional view when a thin film light shielding layer and a thick film light shielding layer of a conventional example are used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2, 2 'light-shielding layer 3 Color filter coloring layer 4 Rise (protrusion) 5 Smooth layer 6, 6' light-cured transparent resin layer 7 Base film 8 light-cured resin film 9 light (UV)

Claims (4)

[Claims] 1. A transparent layer thicker than a light-shielding layer is provided in a gap between light-shielding layer patterns on a transparent substrate so that a light-shielding layer portion at a boundary between respective colored layers of a color filter becomes concave. Color filter substrate. 2. The method according to claim 1, wherein when each colored layer is formed on a transparent substrate having a light-shielding layer, a concave portion having a capacity corresponding to the amount of swelling generated at the boundary between the colored layers is provided. The substrate for a color filter according to claim 1. 3. The color filter substrate according to claim 1, wherein the upper end of the concave portion formed by the light shielding layer pattern and the transparent resin layer provided in the gap has a rounded shape. 4. A photo-curable resin film having a photo-curable transparent resin film layer having a thickness such that the film thickness after curing is larger than the light-shielding layer by a required amount. A first step of pressing against the substrate, a second step of irradiating light from the transparent substrate side to cure the resin layer in the light-shielding layer gap, and a third step of removing the uncured portion by peeling the base film. 4. The method for producing a color filter substrate according to claim 1, further comprising a fourth step of fully curing the color filter substrate.