JPH11160523A - Manufacture of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacture of the color filter which is free of a residue to an adjacent pixel and color mixture. SOLUTION: This color filter has a process for forming a pixel section film 1 of specific BM, etc., on a light-transmissive substrate 2, forming photosensitive resin colored layers 3a-1, 19, and 15, arranging a mask 17 having a specific opening part on the opposite surface of the light-transmissive substrate 2 from the surface where the pixel section film 1 is formed, irradiating the photosensitive resin colored layers 3a-1, 19, and 15 with an active light beam from the reverse surface of the light-transmissive substrate 2 through the mask opening part, and forming specific pixels through development is performed a specific number of times and the γ value of the photosensitive resin is 45 to 90 deg.. Consequently, the color filter is insensitive to light traveling round to below a photomask light shield part owing to the diffraction of the light and the occurrence of a residue to an adjacent pixel can be prevented.

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.

[0002]

2. Description of the Related Art Liquid crystal displays (hereinafter abbreviated as LCDs).
Utilizing features such as thinness, small size, and low power consumption, is currently used for display units such as watches, calculators, TVs, and personal computers. In recent years, color LCDs have been developed and OA / AV
It has begun to be used in many applications such as navigation systems and viewfinders, mainly in equipment, and the market is expected to expand rapidly in the future.

As shown in FIG. 5, a light-shielding layer color filter for displaying a color image on an LCD has a lattice pattern of B-color.
Color pixels 3 (about 100 × 300 × 2 μm) composed of R (red), G (green), and B (blue) are sequentially formed on a substrate 2 such as a glass plate on which an M (black matrix, light shielding layer) 1 is formed. Then, a transparent overcoat (OC) 4 is formed thereon. 5 is a polarizing plate and 6 is an ITO electrode.

[0004] In the color LCD, the color filter 7 has an LC
D, the display screen can be colored by transmitting backlight light through a color filter. 8 is an alignment film, 9 is a liquid crystal, 10 is a seal material, 11 is a top coat layer, 12 is an ITO electrode, 13 is a substrate such as a glass plate, 14
Is a polarizing plate.

At present, color filters are mainly manufactured using a dyeing method. However, in this method, a step of forming a pixel by applying a transparent photosensitive resin on a glass substrate, drying, exposing, and developing, dyeing with a dye, and then forming a color mixing prevention layer is required to be repeated three times. Therefore, the number of steps is large and the cost is high. Further, since a dye is used as a coloring agent, there is a disadvantage that reliability (weather resistance and heat resistance), which is an important issue of a color filter, is inferior.
Therefore, some color filters using a pigment as a coloring agent have been proposed, among which are an electrodeposition method, a printing method, and a photolithography method (photolithography method).

However, in the electrodeposition method, it is necessary to form an electrode pattern. (1) The degree of freedom of the pattern is small (2).
The cost is high, and the printing method is (1) it is difficult to align large substrates and the resolution is low, so it is difficult to respond to miniaturization.
(2) There are problems such as poor pattern flatness, and at present, the photolithography method is considered to be the mainstream. The photolithography method includes a liquid resist method and a film transfer method. In the liquid resist method, a varnish in which a pigment is dispersed in a photosensitive resin is applied on a glass substrate with a spinner, dried,
Exposure and development form color pixels. On the other hand, in the film transfer method, a varnish is formed into a film in the same manner as a photosensitive film for a printed board. After lamination on a substrate, color pixels are formed by exposure and development.

[0007]

Conventionally, a pixel partition film (B
M) requires a light-shielding layer having high light-shielding properties, and metallic chromium having a high optical density per unit film thickness has been applied. In the case of a thin film transistor (TFT) liquid crystal, the optical density of the light shielding layer is required to be 3 or more in order to prevent malfunction of the TFT. To achieve this optical density, a thickness of 0.15 μm was sufficient for chromium metal. However, since the metal chromium reflectance is high, there is a problem that reflection of external light is high when the LCD is used, and visibility is reduced. Therefore,
In order to reduce the reflectance, a method of laminating chromium oxide is adopted, and the visibility is improved. However, there is a problem that the cost is high because metal chromium and chromium oxide are formed by a vacuum deposition method such as sputtering. In order to solve this problem, a resin in which a black coloring layer material such as carbon is dispersed in a photocurable resin, and a resin light-shielding layer in which graphite is dispersed in a thermosetting resin are being adopted.

The resin light-shielding layer needs to be thicker than the metal light-shielding layer in order to obtain a necessary absorbance. By increasing the thickness of the resin light-shielding layer serving as the base, the pixel projections 1 shown in FIG.
6 occurred, and the flatness was impaired.
In order to improve the flatness, a back surface exposure method has been proposed in which a pixel disclosed in Japanese Patent No. 2587653 or JP-A-7-120608 is exposed from the back side through a photomask and a light-shielding layer is used as a part of the photomask. ing. But,
Since a gap corresponding to the thickness of the glass is generated between the photomask and the photosensitive layer, even if adjacent pixels that should not be exposed due to the diffracted light from the photomask are exposed and developed, FIG.
As shown in (1), there is a problem that a residue 21 is generated, resulting in color mixture.

FIG. 2 shows the photosensitive characteristics of the negative photosensitive coloring layer. Above the exposure amount A, the film thickness after development is constant, but below A, the film thickness decreases linearly with decreasing exposure amount.
To obtain a predetermined film thickness, a minimum exposure amount A or more is required. Due to the diffraction of light when the photomask is irradiated with light, as shown in FIG. 3, light goes inside the light-shielding portion edge of the photomask and reaches slightly below the light-shielding portion (pixel partition film). I do. This peripheral indentation becomes larger as the distance between the photomask and the coloring layer becomes larger. The conventional negative-type photosensitive coloring layer is sensitive to even a small amount of light, so the backside exposure method with a 1.1 mm thick transparent substrate between the coloring layer and the photomask allows color printing without residue on adjacent pixels. It was difficult to form a filter. The present invention provides a method for manufacturing a color filter that has no residue on adjacent pixels and no color mixing.

[0010]

According to the present invention, a pixel partition film such as a predetermined BM is formed on a light-transmitting substrate, a photosensitive resin colored layer is formed, and a pixel partition film of the light-transmitting substrate is formed. A mask having a predetermined opening on the back surface of the transparent surface, irradiating the photosensitive resin colored layer with actinic light from the back surface of the light-transmitting substrate through the mask opening, and forming a predetermined pixel by development a predetermined number of times. A method for producing a color filter, wherein the γ value of the photosensitive resin is 45 ° to 90 °. The photomask does not become sensitive to the light that has passed under the light blocking portion of the photomask generated by the diffraction of light, thereby preventing the generation of residues in adjacent pixels.

[0011]

FIG. 3 shows the light intensity of the diffracted light when the gap is 1.1 mm. In order to uniformly expose the entire surface inside the pixel, the exposure amount needs to be four times the minimum exposure amount A. Also,
The exposure amount in the adjacent pixel is about 10% of the exposure amount to be irradiated. That is, the exposure amount 4 × A for uniformly exposing the inside of the pixel.
Is given, the exposure amount at the adjacent pixel is 0.4 × A. The γ value of a general negative photosensitive coloring material is approximately 45 °
Assuming that the minimum exposure amount A is 100 mj / cm ² , a diffracted light of 40 mj / cm ² or less does not remain as a residue. At this time, the width of the pixel partition film which can be ideally made is about 20 μm. As a practical matter, due to the misalignment of the photomask and the glass substrate and the parallelism of the incident light, the width of the pixel partition film that can be dealt with is wide, and it is necessary to produce a high-definition display with a high aperture ratio. It will be difficult. By using a photosensitive colored layer having an exposure γ value of 45 ° to 90 °, the latitude is increased and no residue is generated.

Here, the γ value refers to the slope of the film thickness in a region where the film thickness depends on the exposure amount when the photosensitive colored layer is developed by irradiating the transparent substrate side with active light rays. It is defined as arctan (unit is °) in FIG. γ
The value is determined by the width of the pixel partition film and the thickness of the photosensitive resin colored layer. γ value is a constituent material of the photosensitive colored layer,
It can be arbitrarily changed by selecting the type and amount of the photosensitizer, sensitizer, polymerization inhibitor, polymerization initiator, and ultraviolet absorber.

[0013]

An embodiment of the present invention will be described with reference to FIG. Corning # 1737 glass 200m vertical as transparent substrate
A glass substrate 2 of mx 300 mm wide x 0.7 mm thick was used. The pixel partition film 1 was formed by dispersing carbon in a photocurable resin, and was formed at a predetermined position at 1 μm. At this time, the pattern of the pixel division film has a width of 15 μm, a pitch of 100 μm, a height of 300 μm, and a numerical aperture of 640 × (three colors).
A matrix of 480 rows and columns was used.

Next, a pixel forming process is started. As a photosensitive colored layer, 20 as a base film base material serving as a temporary support
Using a polyethylene terephthalate (PET) film 15 having a thickness of 10 μm and a cushion layer 19 having a thickness of 10 μm as a base film 20, a coloring layer 3 serving as a pixel base material was applied thereon by 1.6 μm. Colored layer (polymer) Styrene, methyl methacrylate, ethyl acrylate, acrylic acid, glycidyl methacrylate copolymer Molecular weight (weight average) about 3.5000, acid value 110 70 parts (monomer) pentaerythritol tetraacrylate 30 parts (photoinitiator ) Irgacure 369 (Ciba Specialty Chemicals) 2.2 parts N, N-tetraethyl-4,4'-diaminobenzophenone 2.2 parts (solvent) propylene glycol monomethyl ether 492 parts (polymerization inhibitor) p-methoxyphenol 0 1 part (colorant) Pigment 22 parts (parts are parts by weight) As shown in FIG.
The value is 87 °, the green γ value is 85 °, and the blue γ value is 87 °. First, as the first color, the red colored layer 3a-1 is laminated on the glass substrate 2 on which the pixel partitioning film 1 has been formed at a laminating temperature of 60 ° C., a laminating speed of 1 m / min, and a roll pressure of 5 kg / cm ² . Next, an exposure step is started. As a light exposure, a photomask 17 is installed at a position (back surface) opposite to the side on which the colored layer 3 is formed using a proximity exposure machine, and the photomask 17 is aligned with a predetermined position of the pixel partition film 1. And exposed at 400 mj / cm ^{2 at} 405 nm from the back through a photomask. Here, the colored layer forming side and the exposure stage 16 were made to face each other. At this time, the opening of the photomask is
The layout was such that each side overlapped by 3 μm.
The gap between the substrate and the photomask was 60 μm. This gap amount may be any value within the range of 0 to 500. Next, the base film 20 is peeled off by a dry method, then developed with an aqueous alkali solution, and thermally cured at 200 ° C.
-1 is formed. This process is repeated for green and blue, and pixel 3
b-2 and the pixel 3b-3 are formed. The order of formation is not limited. After the three colors are formed, washing is performed, and an overcoat is formed thereon as necessary, thereby completing a color filter.

[0015]

In the method of manufacturing a color filter according to the present invention, pixels which should not be cured by exposure adjacent to pixels to be exposed are not cured.

[Brief description of the drawings]

FIG. 1 is a graph for explaining a γ value of a photosensitive colored layer of the present invention.

FIG. 2 is a graph showing the photosensitive characteristics of a negative photosensitive coloring layer.

FIG. 3 is a diagram for explaining light diffraction.

FIG. 4 is a cross-sectional view for explaining a manufacturing process of the color filter according to the present invention.

FIG. 5 is a sectional view of a liquid crystal display.

FIG. 6 is a cross-sectional view of a pixel protrusion generated by a conventional method.

FIG. 7 is a cross-sectional view for explaining a residue on an adjacent pixel in a conventional method.

[Explanation of symbols]

 1. 1. Pixel partition film Glass substrate 3. Color pixels 4. 4. Overcoat layer (OC) Polarizing plate 6. 6. ITO electrode Color filter 8. Alignment film 9. Liquid crystal 10. Seal material 11. Top coat layer 12. ITO electrode 13. Glass substrate 14. Polarizing plate 15. Base film substrate 16. Exposure stage 17. Photo mask 18. Photomask light-shielding film 19. Cushion layer 20. Base film 21. Residue

Continued on the front page (72) Inventor Ken Yoshida 48 Wadai, Tsukuba-shi, Ibaraki Prefecture Tsukuba Research Laboratory, Hitachi Chemical Co., Ltd.

Claims (1)

[Claims] 1. A predetermined pixel partition film is formed on a light-transmitting substrate, a photosensitive resin colored layer is formed, and a predetermined opening is formed on the back surface of the light-transmitting substrate on which the pixel partition film is formed. A method for manufacturing a color filter, comprising arranging a mask having a mask, irradiating the photosensitive resin colored layer with actinic rays from the back surface of the light-transmitting substrate through the mask opening, and forming a predetermined image by development a predetermined number of times. Wherein the γ value of the photosensitive resin is 45 ° to 90 °.