JP2000347021A - Color filter and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter equipped with column-shaped projecting parts for setting thickness of a liquid crystal layer and capable of manufacturing a color liquid crystal display device with excellent display quality and a method for manufacturing the color filter. SOLUTION: The color filter 1 is provided with a transparent protective layer 6 formed with a thermosetting resin so as at least to coat a colored layer 5 and column-shaped projecting parts 7 formed with a photosetting resin on plural specified locations on a substrate 2 so as to protrude from the transparent protective layer 6. This sort of color filter 1 is manufactured by forming the colored layer 5 consisting of plural colors with a specified pattern on the substrate 2, subsequently by forming the transparent protective layer 6 by prebaking the thermosetting resin layer formed on the substrate 2 so as at least to coat the colored layer 5, subsequently by forming the column-shaped projecting parts 7 on plural specified locations of the substrate by exposing and developing the photosetting resin layer formed on the substrate so as to coat the transparent protective layer 6, via a photomask provided with openings corresponding to the pattern to form the column-shaped projecting parts and subsequently by postbaking them.

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 And a TFT array substrate provided with a thin film transistor (TFT element), a pixel electrode and an alignment layer with a predetermined gap therebetween, and injecting a liquid crystal material into the gap to form a liquid crystal layer. There is. 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 in which glass beads or plastic beads are used as spacers when bonding to an array substrate. That is, before bonding the color filter and the TFT array substrate, glass beads or plastic beads having a predetermined diameter and uniform particle size are scattered on one of the color filter and the TFT array as a spacer,
Thereafter, the two substrates are bonded to each other, and the size of the gap between the two substrates, that is, the thickness of the liquid crystal layer is determined based on the diameter of the glass beads or the plastic beads.

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.

First, in the case where glass beads or plastic beads are used as spacers, if the density dispersed on the substrate surface is appropriate and the particles are not evenly dispersed on the substrate surface, the entire color liquid crystal display device is covered. A gap having a uniform size 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. The presence of the spacer causes disturbances in the alignment of the liquid crystal molecules regulated by the alignment film, and in the liquid crystal around the spacer, it becomes impossible to control the alignment by turning ON / OFF the voltage. However, there has been a problem that the display performance such as the above is deteriorated.

[0006]

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.). This color filter forms a colored layer, and after forming a transparent protective layer using a photocurable resin so as to cover the colored layer, a photolithography process using a photosensitive resin is performed at a predetermined position on a black matrix. This forms a columnar convex portion. Since the columnar projections function as spacers, the conventional bead-shaped spacers are not required to be dispersed, and the display performance can be improved even if the columnar projections are not present in the pixel display unit, causing the alignment of the liquid crystal molecules to be disturbed. Will not be adversely affected.

In the formation of the transparent protective layer using the above-mentioned photocurable resin, after applying the photocurable resin, the whole surface or the pattern exposure corresponding to the imposition is performed, and heat treatment is performed after development. . This heat treatment is performed to prevent the surface of the transparent protective layer from being roughened by the development in the photolithography step of forming the columnar protrusions, thereby preventing the function from being deteriorated.

However, the formation of the transparent protective layer requires a heat treatment step in addition to the exposure and development steps of the photocurable resin as described above. There is a problem that the process is complicated because an exposure step is required even if the processing is performed. Further, during the manufacturing process, an exposure apparatus for forming the transparent protective layer and an exposure apparatus for forming the columnar projections are required, so that the production line becomes longer, and there is a limit to the improvement in throughput.

The present invention has been made in view of the above-mentioned circumstances, and has a columnar convex portion for setting the thickness of a liquid crystal layer, and makes it possible to manufacture 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.

[0010]

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, and at least A transparent protective layer formed so as to cover the coloring layer, and a column-shaped convex portion formed at a plurality of predetermined portions on the substrate and projecting from the transparent protective layer, wherein the transparent protective layer is made of a thermosetting resin. Is formed using
The columnar projections were formed using a photosensitive resin.

In the method of manufacturing a color filter according to the present invention, after a colored layer having a plurality of colors is formed on a substrate in a predetermined pattern, a thermosetting resin layer is formed on the substrate so as to cover at least the colored layer. Then, a pre-baking is performed on the thermosetting resin layer to form a transparent protective layer, and thereafter, a photosensitive resin layer is formed on the substrate so as to cover the transparent protective layer, which corresponds to a formation pattern of columnar convex portions. Exposure and development of the photosensitive resin layer through a photomask having an opening to be formed, to form a columnar convex portion at a plurality of predetermined portions on the substrate,
The configuration was such that post baking was performed.

According to the present invention, the transparent protective layer formed by prebaking the thermosetting resin layer is stable with respect to the developing solution at the time of forming the columnar projections, and the surface does not become rough. In addition to flattening the surface, it prevents the components contained in the colored layer from being eluted into the liquid crystal layer, and eliminates the need for a photolithography step in the formation of the transparent protective layer. It has the necessary height as a spacer and can be set with high precision.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below with reference to the drawings.

[0014] 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. Further, columnar convex portions 7 are formed on the transparent protective layer 6 at a plurality of predetermined locations (five locations in FIG. 1) of the black matrix 3.

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 including 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. In addition, for example, by making the colored pattern 5 thinnest in the red pattern 5R and thickening in the order of the green pattern 5G and the blue pattern 5B, an optimal liquid crystal layer thickness may be set for each color of the colored 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. This transparent protective layer 6 is formed using a thermosetting resin. Examples of the thermosetting resin to be used include an acrylic resin, an epoxy resin, a vinyl ether resin, a polyimide resin, a phenol resin, a polyester resin, a melamine resin, and a urea resin.

The thickness of the transparent protective layer 6 can be set in consideration of the light transmittance of the material used, the surface condition of the color filter 1, and the like, and is set, for example, in the range of 0.1 to 2.0 μm. be able to. Such a transparent protective layer 6 is formed so as to cover at least the colored layer 5 which is in contact with the liquid crystal layer when the color filter 1 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. The columnar protrusions 7 have a certain height so as to protrude from the transparent protective layer 6 in a range of about 2 to 10 μm, and the protrusion amount is required for a liquid crystal layer of a color liquid crystal display device. It can be set appropriately from the thickness and the like. The thickness of the columnar protrusions 7 can be appropriately set in a range of about 5 to 50 μm. It can be appropriately set in consideration of the material and the like, for example,
Red pattern 5R and green pattern 5 constituting the colored layer 5
A necessary and sufficient spacer function is expressed in one set of the G and blue patterns 5B. Such columnar projections 7
Is a columnar shape in the illustrated example, but is not limited thereto, and may be a prismatic shape, a truncated pyramid shape, or the like.

The columnar projections 7 are formed using a photosensitive resin. The photosensitive resin can be selected from known negative-type and positive-type 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 transparent protective layer 6 and the columnar projections 7 and the 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 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.

The method of manufacturing a color filter Next, an example embodiment of a color filter manufacturing method of the present invention, an example color filter 1 shown in FIGS. 1 and 2, with reference to FIGS. 3 and 4 explain.

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. 3A).

The formation of the black matrix 3 can be performed, for example, 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.

Next, a transparent protective layer 6 is formed so as to cover the black matrix 3 and the colored layer 5.
(B)). The transparent protective layer 6 is formed by applying a thermosetting resin such as an acrylic resin, an epoxy resin, a vinyl ether resin, a polyimide resin, a phenol resin, a polyester resin, a melamine resin, and a urea resin as described above to a resin having a viscosity. After optimization, it can be formed by applying a known method such as a spin coater or a roll coater so as to cover the black matrix 3 and the colored layer 5, applying a pre-baking treatment, and curing. in this way,
The formation of the transparent protective layer 6 does not require a photolithography step, and the formed transparent protective layer 6 is stable and has a rough surface with respect to a developing solution used in a photolithography step of forming columnar projections described later. It will not be. Therefore, the transparent protective layer 6 can flatten the surface of the color filter and prevent the components contained in the colored layer from being eluted into the liquid crystal layer.

Next, a negative photosensitive resin layer 8 is formed so as to cover the transparent protective layer 6 (FIG. 3C). The photosensitive resin layer 8 is formed by optimizing the viscosity of a known negative photosensitive resin composition and then covering the transparent protective layer 6 by a known means such as a spin coater or a roll coater. It can be formed by coating and drying. Photosensitive resin layer 8
Can be appropriately set according to the height required for the columnar projections 7.

Next, the photosensitive resin layer 8 is exposed through a photomask M for forming columnar projections (FIG. 4A). The photomask M to be used has an opening at a predetermined position for forming the columnar projection 7. Next, the photosensitive resin layer 8 is developed with a developer. As a result of this development, the photosensitive resin layer 8 at the portion where the columnar projections are formed is not dissolved but remains as the columnar projections 7, and the color filter 1 of the present invention is obtained (FIG. 4B). 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.

(Example) As a substrate for a color filter, a glass substrate having a size of 300 mm x 400 mm and a thickness of 1.1 mm (Corning 7059 glass) was prepared. After washing the substrate according to a conventional method, a light-shielding layer (thickness: 0.1 μm) made of metallic chromium was formed on the entire surface of one side of the substrate by a sputtering method. 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 (95 ° 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 obtain a red pattern (1.5 μm
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 thermosetting resin material (Optomer SS6699 manufactured by JSR Corporation) is formed on the substrate on which the colored layer is formed.
G) is applied by a spin coating method to form a thermosetting resin layer, and the thermosetting resin layer is subjected to a prebaking treatment at 120 ° C. for 5 minutes to form a 1.5 μm-thick transparent protective layer. Formed.

Next, on the above-mentioned transparent protective layer, a negative type transparent photosensitive resin material having the following composition, the viscosity of which was adjusted with propylene glycol monomethyl ether acetate, was applied by spin coating, followed by drying. 5.5 μm
Was formed.

Composition of transparent photosensitive resin material Binder resin 150 parts by weight Benzyl methacrylate-methacrylic acid copolymer (molar ratio 73/27) Monomer 80 parts by weight Dipentaerythritol hexaacrylate Polymerization initiator 25 parts by weight Irgacure 369 made by Ciba Specialty Chemical Co., Ltd.

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
400 mJ / through a photomask provided with
cm ^Two Exposure was performed at an exposure amount of

Next, the substrate is washed with a developing solution (potassium hydroxide 0. 1).
05% by weight aqueous solution) for 60 seconds to develop, after washing, post-baking (200 ° C.,
30 minutes). As a result, a transparent columnar convex portion having a height of 5.0 μm was formed on the transparent protective layer at the exposed portion, and the color filter having the structure shown in FIGS. ) Got.

(Comparative Example 1) First, as in the example,
A black matrix and a colored layer were formed. 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 300 mJ / m is applied using a proximity exposure machine.
Exposure was performed at an exposure dose of cm ² . After that, another 20
A heat treatment was performed at 0 ° C. for 30 minutes to form a transparent protective layer having a thickness of 1.5 μm.

Next, columnar projections were formed on the transparent protective layer in the same manner as in the example, to obtain a color filter (Comparative Example 1).

Comparative Example 2 A color filter (Comparative Example 2) was obtained in the same manner as in Comparative Example 1 except that no heat treatment was performed in the step of forming the transparent protective layer.

A transparent conductive layer (0.15 μm thick) made of indium tin oxide (ITO) was formed by a sputtering method on the transparent protective layer of each color filter produced in the above-mentioned Examples and Comparative Examples 1 and 2. Furthermore, after a polyimide alignment layer was provided and subjected to an alignment treatment (rubbing), it was bonded to a TFT array substrate using an epoxy resin sealant, and TN type liquid crystal was sealed in a gap between the color filter and the TFT array substrate. .

In the liquid crystal display devices manufactured using the color filters of Example and Comparative Example 1, a uniform gap is maintained on the entire display surface, the surface of the color filter is flat, and a color layer is contained. Since the components did not elute into the liquid crystal layer, good display quality was obtained without causing color unevenness or the like.

On the other hand, in the liquid crystal display device manufactured using the color filter of Comparative Example 2, the surface smoothness of the transparent protective layer was poor, and good display quality was not obtained.

[0045]

As described above in detail, according to the present invention, since the transparent protective layer is formed by pre-baking the thermosetting resin layer, a photolithography step is not required, and the formed transparent protective layer is formed. The protective layer is stable to the developing solution at the time of forming the columnar projections and does not become rough, so that the surface of the color filter is flattened and the components contained in the colored layer are prevented from being eluted into the liquid crystal layer. In addition, the plurality of columnar protrusions formed by exposing and developing the photosensitive resin layer have a height required as a spacer for setting the thickness of the liquid crystal layer,
Its height can be set with excellent accuracy. Further, in the above-described formation of the transparent protective layer and the columnar projections, the photolithography process is performed once for forming the columnar projections, so that the production line is shortened and the effect of improving the throughput is achieved.

[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 a process diagram illustrating an example of a method for manufacturing a color filter of the present invention.

FIG. 4 is a process chart illustrating an example of a 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 ... Column-shaped convex part 8 ... Photosensitive resin layer

Claims (2)

[Claims] 1. A substrate, a colored layer of a plurality of colors formed in a predetermined pattern on the substrate, a transparent protective layer formed so as to cover at least the colored layer, and a plurality of predetermined layers on the substrate. A column-shaped protrusion formed at a site and protruding from the transparent protection layer, wherein the transparent protection layer is formed using a thermosetting resin, and the column-shaped protrusion is formed using a photosensitive resin. A color filter, characterized in that the color filter is a color filter. 2. After forming a colored layer having a plurality of colors in a predetermined pattern on a substrate, a thermosetting resin layer is formed on the substrate so as to cover at least the colored layer. To form a transparent protective layer by pre-baking, and then form a photosensitive resin layer on the substrate so as to cover the transparent protective layer, and provide a photomask having an opening corresponding to the formation pattern of the columnar protrusions. Exposing and developing the photosensitive resin layer through the substrate to form columnar projections at a plurality of predetermined portions on the substrate, and thereafter performing post-baking.