JPH08262219A - Color filter - Google Patents

Abstract

PURPOSE: To provide a color filter with a light shielding layer having satisfactory light shielding property and less liable to peel. CONSTITUTION: Black matrices 12 as a latticed light shielding layer consisting of graphite, acrylic resin and silicon oxide are formed on a transparent substrate 11 and a protective film 13 consisting of silicon oxide and epoxy resin, epoxy acrylate resin, polyimide resin or acrylic resin is formed on the substrate 11 with the black matrices 12. A colored layer 14 is then formed on the protective film 13 by arranging colored cells 14R, 14G, 14B on the gaps each between the black matrices 12 so that the adjacent cells are made different from each other in color. A transparent electrode 15 of ITO is disposed on the colored layer 14, and the surface of the electrode 15 in contact with a liq. crystal is oriented by rubbing to form an oriented film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter having a colored layer and a light shielding layer made of graphite.

[0002]

2. Description of the Related Art Generally, a color filter used in a liquid crystal display device for color display has, for example, red (R), green (G) or blue (B) on an insulating transparent substrate.
It is formed by arranging a colored layer in which colored cells of primary colors are alternately arranged and a light-shielding layer called a so-called black matrix in a gap portion between the colored cells of the colored layer.

The black matrix, which is a light-shielding layer, separates the apparent colors between the colored cells to improve the color image display quality and the moving image display contrast ratio. In addition, a thin film transistor (TF
In the case of an active matrix type liquid crystal display device using T), it is provided for the purpose of blocking the light radiated to the thin film transistor from the outside in order to prevent malfunction of the thin film transistor due to photocurrent. A material having good appearance and a color close to black is used.

As a conventional color filter,
For example, the configuration shown in FIG. 3 is known.

As shown in FIG. 3, a black matrix 2 as a light-shielding layer made of metallic chromium (Cr) is provided on an insulating transparent substrate 1, and R, G, and B colored cells 3R, 3
The colored layer 3 is formed by arranging G and 3B so that the adjacent colored cells 3R, 3G and 3B have different colors. Then, for example, ITO (Indium Tin Oxid) is formed on the colored layer 3.
A transparent electrode 4 composed of e) is provided, and an alignment film is formed by subjecting the surface of the transparent electrode 4 in contact with the liquid crystal to rubbing alignment treatment.

In the method of manufacturing a color filter, first, a thin film of metallic chromium (Cr) having a thickness of about 0.1 μm is formed on the transparent substrate 1 by a general sputtering or vapor deposition method. The black matrix 2 as a light-shielding layer is formed by patterning by general photo-etching.

Next, after forming the colored layer 3 by a dyeing method, a pigment dispersion method, a printing method, or the like, a transparent electrode 4 made of ITO is formed.

[0008]

However, as described above, although the black matrix 2 of the conventional color filter using the thin film of metallic chromium (Cr) is extremely excellent in the light blocking property, the metallic chromium ( A vacuum film forming apparatus for forming a Cr) thin film is required, and the manufacturing is complicated and time-consuming, and the manufacturing cost is high.

Further, since the material is a thin film of metallic chromium (Cr), when the color filter is incorporated in the liquid crystal display element which becomes the display panel, the metallic chromium (Cr) is formed.
The black matrix 2 reflects the light radiated from the outside onto the entire surface of the display panel, and deteriorates the image quality of the display panel.

Therefore, the material of the black matrix 2 does not require the above vacuum film forming apparatus, and
It has been considered to use a black color resist instead of metallic chromium (Cr) that reflects the irradiated light.

As a black color resist, for example, a black resist B manufactured by Fuji Hunt Technology Co., Ltd.
Using K2000, this black resist is coated on an insulative transparent substrate 1 using a spinner, a so-called spin coater or roll coater, and an oxygen barrier film is formed on this color resist, which is then exposed and developed to form a predetermined pattern. The formation is performed to form the black matrix 2.

As described above, the black matrix 2 using the black color resist does not require a complicated device such as a vacuum film forming device, and can be used by a simple resist coating device such as a general spinner or a developing device. Since the film can be formed, the manufacturing method is simple and does not take time, and the manufacturing cost can be significantly reduced, but the light blocking property is not sufficient and the film thickness needs to be increased. Then, in addition to increasing the film thickness in this way, coloring cells 3R, 3G, 3B
If a transparent electrode or an alignment film is disposed on top of the above, the surface of the alignment film will have conspicuous unevenness, and this unevenness will cause alignment defects when the alignment film is subjected to an alignment treatment. The distance of the gap for enclosing the liquid crystal becomes uneven.

Further, as a substance that is inexpensive and has a high light blocking property, for example, as described in JP-A-6-11613, graphite or the like has an aspect ratio (ratio between particle thickness and width).
Are known to have a layered particle structure of 1:10 or more. For example, in the case of graphite, the distance between carbon atoms between graphite layers is 3.40 angstroms, and van
Since they are bonded only by the der Waals bond, the bond strength between layers is weak, and the strong cleavage (cleavage p
Therefore, when used for the black matrix 2, the film strength is weak and it cannot withstand the physical stress in the cleaning process such as brush cleaning, ultrasonic cleaning and high pressure jet cleaning performed before the formation of the colored layer. In addition, polishing may be performed to improve the smoothness of the colored layer, but the problem that the colored layer is scraped in the polishing process and that when the matrix layer substrate and the counter substrate are assembled together as a component of a liquid crystal display device, In many cases, the sealant for sealing the liquid crystal directly contacts the black matrix 2, and the adhesion of the black matrix to the transparent substrate is weak, so that the adhesion strength between the matrix array substrate and the counter substrate is low. ing.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a color filter having a light-shielding layer which has a good light-shielding property and is hard to peel off.

[0015]

A color filter according to claim 1 is a color filter having a transparent substrate and a light-shielding layer and a coloring layer formed on the transparent substrate.
The light shielding layer is made of graphite and at least one of an organic binder and an inorganic binder.

A color filter according to a second aspect is the color filter according to the first aspect, wherein the organic binder is an acrylic resin, an epoxy resin, an epoxy acrylate resin,
It contains at least one of a polyimide resin and a nylon resin.

The color filter according to claim 3 is the color filter according to claim 1, wherein the inorganic binder is silicon oxide, aluminum oxide, boron oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, nickel oxide and It contains at least one of titanium oxides.

[0018]

In the color filter of the present invention, the light shielding layer is made of graphite,
Since it is composed of at least one of the organic binder and the inorganic binder, it is possible to improve the light-shielding property by graphite, and at the same time, peeling by the binder of at least one of the organic binder and the inorganic binder. To prevent.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the color filter of the present invention will be described below with reference to the drawings.

In FIG. 1, 11 is a transparent substrate, and this transparent substrate 11 is, for example, glass or an optical resin (polycarbonate, polymethylmethacrylate, polyethylene terephthalate, polyimide, polyethylene, polyester, polyarylate, polysulfone polyetherimide, Alternatively, a black matrix 12 as a lattice-shaped light-shielding layer made of graphite, acrylic resin and silicon oxide is formed on the transparent substrate 11 and is transparent through the black matrix 12. A protective film 13 made of silicon oxide, epoxy resin, epoxy acrylate resin, polyimide resin or acrylic resin is formed on the substrate 11.

Further, the black matrix of this protective film 13
Colored cells 14R, 14G, and 14B of the respective colors R, G, and B are adjacent to each other in the gap between the colored cells 14R, 14G, and 14B.
The colored layers 14 are formed by arranging so that the colors of B are different from each other. Then, for example, ITO is formed on the colored layer 14.
A transparent electrode 15 made of (Indium Tin Oxide) is provided,
An alignment film is formed by rubbing the surface of the transparent electrode 15 in contact with the liquid crystal.

Here, a method for forming the black matrix 12 will be described.

First, a water-soluble negative resist (NONCRON-900 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied on the transparent substrate 11 to a predetermined thickness using a spinner, and the black matrix 12 is not formed through a photolithography process. Patterning is performed so that the resist remains on the portion. At that time, the cross-sectional shape of the resist is preferably an inverse taper shape in which the side in contact with the substrate is short. Further, on the transparent substrate 11 on which the resist pattern is formed, 4% by weight of graphite, 0.9% by weight of water-soluble acrylic resin, 0.8% by weight of colloidal silica (silicon oxide) and 0.1% by weight of iron oxide. %, 0.6% by weight of a surfactant, 1% by weight of ammonia water having a concentration of 28% by weight, and the rest being water to form a light-shielding layer-forming aqueous solution with a spinner to a predetermined film thickness.
After that, by drying in air at 70 ° C for 30 minutes,
A graphite film is obtained. Next, the unexposed portion of the resist is decomposed and removed using a saturated aqueous solution of sulfamic acid. afterwards,
The black matrix 12 is formed by removing the graphite film and the resist which are not in contact with the transparent substrate 11 with a high-pressure water stream, and baking them in the air at 200 ° C. for 1 hour.

After this, a silicon oxide film forming coating solution (OCD
-1500-T, manufactured by Tokyo Ohka Kogyo Co., Ltd.) to a predetermined film thickness using a spinner, and 500 ° C., 30
Protective film 13
To form.

According to the experiment, as shown in Table 1,
The conventional black resist has a film thickness of 1.3 μm when the optical density is 2.0, and a film thickness of 2.2 μ when the optical density is 3.5.
m, the black matrix of the above embodiment
12 has a high optical density of 1.0 μm or less, such as a film thickness of 0.4 μm when the optical density is 2.0 and a film thickness of 0.7 μm when the optical density is 3.5. As a result, a sufficient light blocking property is realized, which is about 1/3 of the film thickness of the conventional example.
It becomes the following. Further, unlike the case of metallic chromium (Cr), since a complicated device such as a vacuum film forming device is not used, the film can be formed at a low cost.

[0026]

[Table 1] Next, another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 2 is different from the embodiment shown in FIG. 1 in that the protective film 13 is not provided.

Now, a method of forming the black matrix 12 shown in FIG. 2 will be described.

First, a positive resist (O
FPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to a predetermined film thickness by using a spinner, and is patterned through a photolithography process so that the resist remains in a portion where the black matrix 12 is not formed. Then, 6% by weight of graphite, 1.5% by weight of water-soluble acrylic resin, 1% by weight of colloidal silica (silicon oxide), 0.1% by weight of nickel oxide, and 0.1% by weight of interface on the transparent substrate 11 on which the resist pattern is formed. An aqueous solution for forming a light-shielding layer containing 0.8% by weight of an activator, 1% by weight of ammonia water having a concentration of 28% by weight, and the balance being water is coated with a spinner to a predetermined film thickness.
After that, a graphite film is obtained by drying in air at 70 ° C. for 30 minutes. Next, the resist in the unexposed portion is decomposed and removed using a 2 wt% sodium hydroxide aqueous solution. After that, the graphite film and the resist in the portion not in contact with the transparent substrate 11 are removed by a high-pressure water flow, and the black matrix 12 is formed by baking in the air at 180 ° C. for 1 hour.

According to the experiment, as shown in Table 1 above, the conventional black resist has a film thickness of 1.3 μm when the optical density is 2.0 and a film thickness when the optical density is 3.5. In contrast to the thickness of 2.2 μm, the black matrix 12 of the above embodiment has a thickness of 0.5 when the optical density is 2.0.
When the optical density is 3.5 μm and the optical density is 3.5, the film thickness is 0.9 μm, so that a high optical density can be obtained with a film thickness of 1.0 μm or less and sufficient light blocking property is realized. It is about 1/2 or less of the film thickness. Further, unlike the case of metallic chromium (Cr), since a complicated device such as a vacuum film forming device is not used, the film can be formed at a low cost.

In each of the embodiments, the photolithography technique was used as a method for patterning the black matrix 12 into a predetermined pattern. However, a printing method such as a method using a solvent suitable for print transfer, or another method is used. You may form a pattern by the method.

Although the spinner is used as the coating method of the protective film 13 on the upper surface of the black matrix 12, it may be formed by another method such as dipping or spraying.

Furthermore, when inexpensive alkali glass is used as the transparent substrate 11, silicon dioxide is generally applied as a thin film on the surface of the alkali glass as a film for preventing migration of alkali ions to the liquid crystal layer. In the filter, the protective film 13 on the upper surface of the black matrix 12
By using silicon oxide or the like as the material, the silicon dioxide film on the surface of the alkali glass can be eliminated.

The binder of the black matrix 12 is
Not limited to the above, acrylic resin that is an organic binder,
Epoxy resin, epoxy acrylate resin, polyimide resin or nylon resin, and at least one of inorganic binders such as silicon oxide, aluminum oxide, boron oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, nickel oxide and titanium oxide. The same effect can be obtained even with one of them.

The content of the organic binder is preferably 1 to 30% by weight, regardless of whether or not the inorganic binder is contained. When the content is less than 1% by weight, the film strength of the black matrix 12 is obtained. If the content is more than 30% by weight, coating is difficult and the patterning property is poor.

Further, in any of the above-mentioned examples, the use of graphite can improve the contrast, and since a sufficient optical density can be obtained with a thin film thickness, an alignment defect or the like occurs in the alignment film. Without having a sufficient film strength as the black matrix 12, the black matrix 12 is not damaged or peeled off in the cleaning step, and the problem of peeling the seal does not occur even when the liquid crystal display device is formed.

A protective film 13 is formed on the black matrix 12.
When the black matrix 12 is provided, the black matrix 12 is not damaged or peeled off in the polishing process.

Further, the material cost is lower than that of the black resist, and metal chromium (C
Since the reflectance of light is lower than that of r), when the display panel is constructed, for example, the black matrix 12 does not reflect the light radiated from the outside to the front surface of the display panel to deteriorate the image quality of the display panel.

[0039]

According to the color filter of the present invention, since the light-shielding layer is composed of graphite and at least one of the organic binder and the inorganic binder, the graphite can improve the light-shielding property. At the same time, peeling can be prevented by at least one of the organic binder and the inorganic binder, and the durability can be improved at a low cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a color filter of the present invention.

FIG. 2 is a sectional view showing an embodiment of the same.

FIG. 3 is a cross-sectional view showing a conventional color filter.

[Explanation of symbols]

 11 Transparent substrate 12 Black matrix as a light shielding layer 14 Colored layer

Claims (3)

[Claims] 1. A color filter having a transparent substrate and a light-shielding layer and a colored layer formed on the transparent substrate, wherein the light-shielding layer is made of graphite and at least one of an organic binder and an inorganic binder. A color filter comprising a binder. 2. The color filter according to claim 1, wherein the organic binder contains at least one of acrylic resin, epoxy resin, epoxy acrylate resin, polyimide resin and nylon resin. 3. The inorganic binder contains at least one of silicon oxide, aluminum oxide, boron oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, nickel oxide and titanium oxide. The color filter according to claim 1.