JP2001221911A - Color filter and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter which is provided with columnar projections to determine the thickness of a liquid crystal layer and which enables the production of a color liquid crystal display device with excellent display quality, and to provide a method of producing the color filter. SOLUTION: The color filter is provided with a color layer of a plurality of colors formed into a specified pattern on a substrate and transparent columnar projections formed in a plurality of specified positions on the substrate, with each columnar projection having a plurality of small projections on its upper end. The color filter is produced by forming a color layer of a plurality of colors into a specified pattern on the substrate, forming a photosensitive resin layer on the substrate to cover at least the color layer, exposing the photosensitive resin layer though a specified photomask having opening corresponding to the pattern of the columnar projections to be formed with each opening consisting of a group of minute opening, and developing the resin layer to from the transparent columnar projections in a plurality of specified positions on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color filter and a method of manufacturing the same, and more particularly, to a color filter capable of manufacturing a color liquid crystal display device having excellent display quality and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, color liquid crystal display devices have attracted attention as flat displays. As an example of the color liquid crystal display device, a black matrix, a colored layer composed of a plurality of colors (usually three primary colors of red (R), green (G), and blue (B)), a transparent conductive layer (common electrode), and an alignment layer A color filter comprising: a thin film transistor (TFT element);
There is a type in which a pixel electrode and a TFT array substrate provided with an alignment layer face each other with a predetermined gap therebetween, and a liquid crystal material is injected into the gap to form a liquid crystal layer. In such a color liquid crystal display device, the gap portion is the thickness of the liquid crystal layer itself, and enables good display performance such as high-speed response, high contrast ratio, and wide viewing angle required for the color liquid crystal display device. It is necessary to keep the thickness of the liquid crystal layer, that is, the gap distance between the color filter and the TFT array substrate strictly constant.

Conventionally, as a method of determining the thickness of a liquid crystal layer in a color liquid crystal display device, a color filter and a TFT are used.
There is a method of injecting a liquid crystal in which a number of particles or rods called spacers made of glass, alumina, plastic, or the like are mixed into a gap between the array substrate and the substrate. The size of the gap between the two substrates, that is, the thickness of the liquid crystal layer is determined by the size of the spacer.

However, the above-described color filter and T
The method of forming the gap with the FT array substrate has the following problems in the operation of the color liquid crystal display device.
That is, if the density of the spacers scattered on the substrate surface is appropriate and the spacers are not uniformly dispersed on the substrate surface, a gap portion having a uniform size over the entire surface of the color liquid crystal display device is not formed. . In general, when the scattered amount (density) of the spacers is increased, the deviation in the thickness of the gap decreases, but as the scattered amount (density) increases, the number of spacers present on the display pixel portion also increases, and the display pixel portion increases. In this case, the spacer becomes a foreign matter of the liquid crystal material. And
Due to the presence of the spacer, the alignment of the liquid crystal molecules regulated by the alignment film is disturbed, and only the liquid crystal around the spacer becomes difficult to control the alignment by turning on and off the voltage. There is a problem that display performance is reduced.

[0005]

In order to solve such a problem, a color filter having a columnar convex portion for determining a gap (the thickness of a liquid crystal layer) has been proposed (JP-A-4-318816). No.). In this color filter,
After a colored layer is formed and a protective layer is formed so as to cover the colored layer, a columnar convex portion is formed at a predetermined position on a black matrix by a photolithography process using a photosensitive resin. However, with the recent increase in the definition of black matrices and TFTs, thinner columnar projections are required. However, the conventional narrower columnar projections are required when assembling a color filter and a TFT array substrate. However, there is a problem in that deformation, destruction, and the like may occur without being able to withstand the load imposed on the spacer, thereby impairing the function as a spacer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has a columnar convex portion for setting the thickness of a liquid crystal layer, and enables the manufacture of a color liquid crystal display device having excellent display quality. An object of the present invention is to provide a color filter and a method for manufacturing the color filter.

[0007]

In order to achieve the above object, a color filter according to the present invention comprises a substrate, a colored layer of a plurality of colors formed in a predetermined pattern on the substrate, A transparent columnar projection formed at a plurality of upper predetermined portions; and the columnar projection has a plurality of small projections at an upper end.

Further, the color filter of the present invention includes a transparent protective layer formed so as to cover at least the colored layer, and the columnar convex portion is provided on the transparent protective layer.

In the method of manufacturing a color filter according to the present invention, after forming a colored layer having a plurality of colors in a predetermined pattern on a substrate, a photosensitive resin layer is formed on the substrate so as to cover at least the colored layer. Exposing and developing the photosensitive resin layer via a predetermined photomask to form transparent columnar protrusions at a plurality of predetermined portions on the substrate, wherein the photomask is formed of a columnar protrusion. An opening corresponding to the formation pattern was provided, and each opening was configured to be a set of minute openings.

According to the present invention, the plurality of small projections provided at the upper end of the columnar convex portion increase the surface area of the upper end portion even if the columnar convex portion is narrower, so that the color filter and the TFT array substrate have a larger surface area. The load applied to the upper end of the columnar protrusion during assembly is dispersed by the small protrusion, and the deformation of the columnar protrusion due to this load stops at the deformation of the small protrusion, and the function as a spacer is not impaired.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below with reference to the drawings. Color Filter Figure 1 is a partial plan view showing an example of an embodiment of a color filter of the present invention, FIG. 2 is a longitudinal sectional view along the line A-A. 1 and 2, a color filter 1 of the present invention includes a substrate 2, a black matrix 3 and a coloring layer 5 formed on the substrate 2, and a transparent protective film covering the black matrix 3 and the coloring layer 5. A layer 6 is formed, and transparent columnar projections 7 are provided at a plurality of predetermined locations (five locations in FIG. 1) of the black matrix 3.
Is formed on the transparent protective layer 6 described above.

Substrate 2 constituting color filter 1 described above
For example, a transparent rigid material having no flexibility such as quartz glass, Pyrex glass, or a synthetic quartz plate, or a transparent flexible material having flexibility such as a transparent resin film or an optical resin plate can be used. Of these, Corning 7059 glass is a material having a low coefficient of thermal expansion, excellent dimensional stability and workability in high-temperature heat treatment, and is an alkali-free glass containing no alkali component in the glass. It is suitable for a color filter for a color liquid crystal display device according to the method.

The black matrix 3 constituting the color filter 1 is provided between the display pixel portions composed of the colored layers 5 and outside the region where the colored layers 5 are formed. Such a black matrix 3 is formed by forming a metal thin film of chromium or the like having a thickness of about 1000 to 2000 ° by a sputtering method, a vacuum evaporation method, or the like, and patterning the thin film, and containing light-shielding particles such as carbon fine particles. Forming a resin layer of polyimide resin, acrylic resin, epoxy resin, etc., and forming a photosensitive resin layer containing light-shielding particles such as carbon fine particles, metal oxides, etc. The photosensitive resin layer may be formed by patterning the photosensitive resin layer.

The coloring layer 5 has a red pattern 5R, a green pattern 5G and a blue pattern 5B arranged in a desired pattern shape, and is formed by a pigment dispersion method using a photosensitive resin containing a desired coloring material. And a known method such as a printing method, an electrodeposition method, and a transfer method. Further, for example, the color pattern 5 may be thinnest in the red pattern 5R and thicker in the order of the green pattern 5G and the blue pattern 5B, so that the optimal liquid crystal layer thickness may be set for each color of the color layer 5. .

The transparent protective layer 6 is provided for flattening the surface of the color filter 1 and for preventing components contained in the colored layer 5 from being eluted into the liquid crystal layer. The thickness of the transparent protective layer 6 depends on the light transmittance of the material used,
It can be set in consideration of the surface condition of the color filter 1 and the like, and can be set, for example, in the range of 0.1 to 3 μm. Such a transparent protective layer 6 is used for the color filter 1.
Is formed so as to cover at least the colored layer 5 which is in contact with the liquid crystal layer when the TFT is bonded to the TFT array substrate.

The columnar projections 7 are formed by connecting the color filter 1 to a TFT.
It functions as a spacer when bonded to an array substrate. FIG. 3 is an enlarged perspective view of such a columnar projection 7. As shown in FIG. 3, the columnar convex portion 7
The upper end is provided with a plurality (four in the illustrated example) of small projections 7a.

The columnar protrusions 7 have a certain height so as to protrude from the transparent protective layer 6 in the range of about 2 to 10 μm, and the protrusion amount is equal to the liquid crystal layer of the color liquid crystal display device. It can be set appropriately from the required thickness and the like. In addition, the thickness of the columnar convex portion 7 can be appropriately set in a range of about 5 to 30 μm. On the other hand, the number of small projections 7a is preferably about 2 to 6, and the height of one small projection 7a can be appropriately set in a range of about 0.1 to 0.5 μm. The thickness of the small projections 7a is preferably in the range of about 5 to 10 μm in consideration of the resolution of the material (transparent photosensitive resin) to be used.

The formation density of the columnar projections 7 can be appropriately set in consideration of the thickness unevenness of the liquid crystal layer, the aperture ratio, the shape and material of the columnar projections 7, and the like. The necessary and sufficient spacer function is expressed in one set of the red pattern 5R, the green pattern 5G, and the blue pattern 5B constituting the fifth pattern 5. The shape of the columnar convex portion 7 is a prismatic shape in the illustrated example, but is not limited thereto, and may be a cylindrical shape, a truncated cone shape, or the like. The number of the small projections 7a can be appropriately set in the range of 2 to 6, and the shape of the small projections 7a is not particularly limited.

The columnar projection 7 is formed using a transparent photosensitive resin. The transparent photosensitive resin can be selected from publicly known negative-type and positive-type transparent photosensitive resins in consideration of the mechanical strength and the like required for the columnar projections 7.

When an alignment layer is provided on the color filter 1 of the present invention having the above-mentioned transparent protective layer 6 and columnar projections 7 and alignment processing (rubbing) is performed, and then the TFTs are bonded to a TFT array substrate, the columnar projections 7 A gap is formed between the color filter 1 and the TFT array substrate. And, as described above, since the columnar projection 7 has a plurality of small projections 7a at the upper end, even if the columnar projection 7 is thin, the surface area of the upper end is large, and when the color filter and the TFT array substrate are assembled. Columnar projection 7
Even if a load is applied to the upper end of this, this load is distributed to the plurality of small projections 7a. For this reason, the deformation of the columnar convex portion 7 due to the load during processing stops at the deformation of the small projection 7a,
The function of the columnar projection 7 as a spacer is maintained, and the gap accuracy between the two substrates is extremely high. Note that the color filter of the present invention may not include the black matrix 3 and may have the above-described columnar convex portion 7 formed at a position corresponding to a non-pixel portion.

In the above-described embodiment of the color filter, the columnar projections 7 are formed in a sea-island shape on the transparent protection layer 6, but the transparent protection layer 6 and the transparent columnar projections 7 are integrally formed. It may be formed.

The method of manufacturing a color filter Next, an example embodiment of a color filter manufacturing method of the present invention, the color filter 1 shown in FIGS. 1 to 3
Will be described with reference to FIGS. 4 and 5.

In the method for manufacturing a color filter according to the present invention,
First, a black matrix 3 is formed on the substrate 2, and then a red pattern 5R is formed in a red pattern forming region, a green pattern 5G is formed in a green pattern forming region, and a blue pattern 5B is formed in a blue pattern forming region on the substrate 2. To form a colored layer 5 (FIG. 4A). Next, a negative-type transparent photosensitive resin layer is formed so as to cover the black matrix 3 and the colored layer 5, and is exposed to form a transparent protective layer 6 (FIG. 4B). Next, a negative-type transparent photosensitive resin layer 8 is formed so as to cover the transparent protective layer 6 (FIG. 4C).

The formation of the black matrix 3 is as follows.
For example, it can be performed as follows. First, a light-shielding layer formed of a metal thin film such as chromium formed by a sputtering method, a vacuum evaporation method, or the like, a resin layer containing light-shielding particles such as carbon fine particles, or the like is formed on the substrate 2, and a known light-shielding layer is formed on the light-shielding layer. A photosensitive resist layer is formed using a positive or negative photosensitive resist. Next, the black matrix 3 is formed by exposing and developing the photosensitive resist layer through a black matrix photomask, etching the exposed light shielding layer, and removing the remaining photosensitive resist layer.

The formation of the colored layer 5 is performed, for example, by
It can be performed as follows. First, a red photosensitive resin layer containing a red coloring material is formed on the substrate 2 so as to cover the black matrix 3, and the red photosensitive resin layer is exposed to light through a predetermined photomask and developed. Thereby, a red pattern 5R is formed in the red pattern forming region on the substrate 2. Hereinafter, similarly, a green pattern 5G is formed in a green pattern formation region on the substrate 2, and further, a blue pattern 5B is formed in a blue pattern formation region on the substrate 2.

The transparent protective layer 6 is formed by, for example, optimizing the viscosity of a known negative-type transparent photosensitive resin composition and then using a known means such as a spin coater or a roll coater. Black matrix 3 and colored layer 5
Can be formed by applying a coating so as to cover and curing the film by exposure.

Further, the transparent photosensitive resin layer 8 is formed by optimizing the viscosity of a known negative-type transparent photosensitive resin composition and then using a known means such as a spin coater or a roll coater. It can be formed by coating and drying so as to cover the transparent protective layer 6. The thickness of the transparent photosensitive resin layer 8 can be appropriately set according to the height required for the columnar projections 7.

Next, the negative type transparent photosensitive resin layer 8 is exposed through a photomask 11 for forming columnar convex portions (FIG. 5).
(A)). The photomask 11 used has an opening 12 at a predetermined position for forming the columnar projection 7. FIG.
FIG. 3 is a partially enlarged perspective view of such an opening 12 of the photomask 11. As shown in FIG. 6, the opening 12 of the photomask 11 is a set of a plurality (four in the illustrated example) of small openings 12a. The size of such a minute opening 12a can be appropriately set within a range of about 2 to 6 μm, which is larger than the resolution of the negative type transparent photosensitive resin layer 8 to be used.

Next, the transparent photosensitive resin layer 8 is developed with a developing solution. As a result of this development, the transparent photosensitive resin layer 8 at the portion where the columnar projections are formed is not dissolved, and the transparent columnar projections 7 are not dissolved.
Remains as. Further, the transparent photosensitive resin layer 8 in a region other than the minute region exposed through the minute opening 12a in each of the columnar projecting portion forming portions is partially dissolved and removed. The projections 7a (not shown) are formed, and the color filter 1 of the present invention is obtained (FIG. 5B). In the above embodiment, the coloring layer 5 is formed by a pigment dispersion method, but the present invention is not limited to this. For example, a printing method, a transfer method, or the like can be used, and a transparent conductive film can be formed on the substrate 2 in advance, and an electrodeposition method can be used.

[0030]

Next, the present invention will be described in more detail with reference to examples. 300mm × as substrate for color filter
A glass substrate (Corning 7059 glass) having a thickness of 400 mm and a thickness of 1.1 mm was prepared. After washing the substrate according to a conventional method, a light-shielding layer (thickness 0.1 μm) made of metallic chromium is formed on one side of the substrate by sputtering.
Was formed. Next, the light-shielding layer was subjected to photosensitive resist coating, mask exposure, development, etching, and resist layer peeling by a normal photolithography method to form a black matrix.

Next, a photosensitive coloring material for red pattern (Color Mosaic CR-700 manufactured by Fuji Film Ohrin Co., Ltd.) is applied over the entire surface of the substrate on which the black matrix is formed.
1) was applied by spin coating to form a red photosensitive resin layer, and prebaked (85 ° C., 5 minutes). Thereafter, the red photosensitive resin layer is aligned and exposed using a predetermined colored pattern photomask, and is developed with a developing solution (a diluting solution of a color mosaic developing solution CD manufactured by Fuji Film Olin Co., Ltd.). Post bake (200
At 30 ° C. for 30 minutes) to form a red pattern (1.5 μm thick) at a predetermined position with respect to the black matrix pattern.
m) was formed.

Similarly, a photosensitive coloring material for a green pattern (Color Mosaic CG-Fuji Film Orin Co., Ltd.)
7001), a green pattern (thickness: 1.5 μm) was formed at a predetermined position with respect to the black matrix pattern. Further, a photosensitive coloring material for a blue pattern (Color Mosaic CB-Fuji Film Olin Co., Ltd.)
7001), a blue pattern (thickness: 1.5 μm) was formed at a predetermined position with respect to the black matrix pattern.

Next, a negative-type transparent photosensitive resin material (NN550, manufactured by JSR Corporation) is applied on the substrate on which the colored layer is formed by spin coating, and is exposed to light to a thickness of 1.5 μm.
Was formed.

Next, a negative type transparent photosensitive resin material (NN700 manufactured by JSR Corporation) was applied on the transparent protective layer by a spin coating method and dried to form a 6 μm thick transparent photosensitive resin layer. .

Next, a projector using an ultra-high pressure mercury lamp as an exposure light source.
Use a roximity exposure machine to form a columnar projection
250mJ / through a photomask with a hole opening
cm ^Two Exposure was performed at an exposure amount of Photomask used
As shown in FIG. 6, the opening has a side length of 4 μm.
Four square micro openings arranged at a pitch of 2μm
It was done.

Next, the substrate was washed with a developing solution (KOH 2.0% by weight).
Aqueous solution) for 60 seconds to develop, after washing, post-baking in a clean oven (200 ° C, 30 minutes)
Was done.

By such a series of processes, the exposed portion becomes a 5.5 μm-high transparent prismatic columnar protrusion, and the upper end of each columnar protrusion has a side length of 3 μm, Four small prism-shaped projections with a height of 0.5 μm are formed,
A color filter (Example) having a structure as shown in FIGS. 1 to 3 was obtained.

For comparison, a color filter was prepared in the same manner as in the embodiment except that a photomask having a square opening having a side of 10 μm and having no minute opening was used instead of the above photomask. (Comparative example) was obtained. The loads shown in Table 1 below were applied to the upper ends of the columnar projections of the color filters (Examples and Comparative Examples), and the results of observing deformation and destruction of the columnar projections are shown in Table 1 below.

[0039]

[Table 1] As shown in Table 1, in the color filter of the present invention,
Even when a load of 100 kg / mm ² was applied, small projections were deformed, but no destruction occurred in the columnar projections. However, in the comparative color filter, destruction occurred in the columnar projection at a load of 80 kg / mm ² .

[0040]

As described above in detail, according to the present invention, the plurality of transparent columnar projections have a height required as a spacer for setting the thickness of the liquid crystal layer, and a plurality of small projections are provided at the upper end thereof. Therefore, even if the columnar projection is thin, the surface area of the upper end becomes large, and even if a load is applied to the upper end of the columnar projection when assembling the color filter and the TFT array substrate, this load is small. The deformation of the columnar protrusions is stopped by the deformation of the small protrusions, preventing the scattering due to the destruction of the columnar protrusions, and also maintaining the function as a spacer, and improving the definition of the black matrix and TFT. Correspondingly, the columnar projections can be made thinner, and a color liquid crystal display device that requires high precision in controlling the thickness of the liquid crystal layer, for example, a color liquid crystal display device in an IPS (In-Plane Switching) liquid crystal mode It is possible to cope with, it is possible to better display quality reliable color liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing an example of an embodiment of a color filter of the present invention.

FIG. 2 is a diagram illustrating a color filter according to the present invention shown in FIG.
It is a longitudinal cross-sectional view in the A line.

FIG. 3 is an enlarged perspective view of a columnar protrusion of the color filter of the present invention shown in FIG.

FIG. 4 is a process chart illustrating an example of a method for manufacturing a color filter of the present invention.

FIG. 5 is a process chart illustrating an example of a method for manufacturing a color filter of the present invention.

FIG. 6 is a partially enlarged perspective view showing an example of a photomask used in the method for manufacturing a color filter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Color filter 2 ... Substrate 3 ... Black matrix 5 ... Coloring layer 6 ... Transparent protective layer 7 ... Columnar convex part 7a ... Small protrusion 8 ... Transparent photosensitive resin layer 11 ... Photomask 12 ... Opening 12a ... Micro opening

Continued on the front page F-term (reference) 2H048 BB08 BB37 BB42 2H091 FA02Y FA35Y FC10 FD06 GA08 GA11 LA02 LA30 5C094 AA03 AA08 AA36 AA43 AA47 AA48 AA55 BA43 CA19 CA24 DA12 DA13 EC03 ED03 FA01 FB01 A12 CCB HH02 KK07

Claims (3)

[Claims] 1. A substrate comprising: a substrate; a colored layer of a plurality of colors formed in a predetermined pattern on the substrate; and transparent columnar protrusions formed at a plurality of predetermined portions on the substrate. The color filter, wherein the projection has a plurality of small projections at an upper end. 2. The color filter according to claim 1, further comprising a transparent protective layer formed so as to cover at least the coloring layer, wherein the column-shaped protrusions are provided on the transparent protective layer. . 3. After forming a colored layer of a plurality of colors in a predetermined pattern on a substrate, a photosensitive resin layer is formed on the substrate so as to cover at least the colored layer, and a predetermined photomask is interposed therebetween. Exposing and developing the photosensitive resin layer, and forming a transparent columnar convex portion at a plurality of predetermined portions on the substrate, wherein the photomask has openings corresponding to the formation pattern of the columnar convex portion. A method for manufacturing a color filter, wherein each opening is a set of minute openings.