JPH0743519A - Color filter - Google Patents

Abstract

PURPOSE:To make thickness of a photoresist as small as possible, to prevent increase in the pattern exposure time and to improve precision in the pattern edge of the black matrix pattern when the black matrix pattern of a color filter is formed by a photofabrication (photolithographic) method. CONSTITUTION:This color filter consists of a black matrix pattern 2, filter color pattern comprising each color pattern of blue, green, and red, and transparent conductive layer, etc. The black matrix pattern 2 consists of a first pattern layer 3 formed of a halftransparent or opaque indium oxide film and a second pattern layer 4 formed oa light-shading photosensitive resin matched to and lamination on the first pattern layer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter for a liquid crystal display device, and more particularly to a color filter for a liquid crystal display device which has low reflection with respect to external light.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3A, a color filter for a liquid crystal display device or the like has a light-shielding property formed on a glass substrate 11 in a regular parallel line shape, a grid shape or the like. (Or light absorbing) black matrix pattern 1
2 is provided, and the black matrix pattern 1 shown in FIG.
2, a filter color pattern 15 composed of blue, green, and red color patterns is provided.
A transparent protective film and a transparent conductive film (not shown) are appropriately laminated on the upper side of the black matrix pattern 12 and the filter color pattern 15.

In the above color filter, it is necessary to arrange the black matrix pattern 12 and the filter color pattern 15 so as to be in close contact with each other so that no void is formed in the adjacent portion between the black matrix pattern 12 and the filter color pattern 15. Therefore, the filter color pattern 15 is provided so as to overlap the black matrix pattern 12.

The black matrix pattern 12 is
When forming a pattern on the glass substrate 11, an opaque metal such as chromium (Cr), an oxide such as chromium oxide (CrO), or a material such as a black photoresist is used. In addition, for example, JP-A-63-2827
As in No. 02, a black matrix having a two-layer structure of a chrome layer and a photoresist layer has also been proposed.

[0005]

However, these methods have the following problems. That is, when an opaque metal such as chrome is used, when incorporated in a liquid crystal display device, the light reflectance with respect to external light is large, and the display quality deteriorates. Further, in the case of using an oxide such as chromium oxide, there are problems that the light-shielding effect is low and the chromium oxide film formation cost is high.

Further, when a black matrix is formed by a photofabrication (photolithography) method using a black photoresist (pigment-dispersed photoresist), there is an advantage that it is low in reflection against external light. However, the light-shielding effect is not sufficient, and there is a problem in that switching characteristics are deteriorated particularly when a driving method using a TFT (thin film transistor), which has been increasing in recent years, is adopted. If the thickness of the black photoresist (for example, about 1.2 μm) is increased in order to improve the light-shielding effect, the smoothness of the color filter is affected, causing a gap defect in the liquid crystal layer when incorporated in a liquid crystal display device. There was a problem that became. In addition, since black photoresist is applied thickly and then pattern exposure is performed,
There was also a problem that the curing was insufficient and the resolution deteriorated. Further, the black matrix having a two-layer structure of a chromium layer and a photoresist layer has a problem that the reflectance on the chromium surface is large.

An object of the present invention is to provide a color filter having a light-shielding layer which has low reflection against external light, has a sufficient light-shielding effect, and has no problem in smoothness.

[0008]

The present invention provides a glass substrate 1
Black matrix pattern 2 on top, and Blue, Gr
The black matrix pattern 2 includes a first pattern layer 3 formed of translucent or opaque indium oxide, and a filter color pattern 5 including een and Red color patterns and a transparent conductive film. It is a color filter characterized by being constituted by two layers, that is, a second pattern layer 4 formed of a light-shielding photosensitive resin which is laminated on one pattern layer in a matched manner.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The color filter of the present invention will be described in detail below with reference to one embodiment shown in FIGS. 1 and 2. As shown in FIG. 1, regular parallel lines on a transparent glass substrate 1, A light-shielding (or light-absorbing) black matrix pattern 2 having a lattice shape or the like is provided.

The black matrix pattern 2 formed on the glass substrate 1 is exposed under an atmosphere of low oxygen concentration,
Alternatively, in an atmosphere in which oxygen is excluded, a semitransparent film (for example, a transmittance of about 20% to 30%) formed into a predetermined film thickness by vacuum deposition, sputtering, or the like or opaque indium oxide (In ₂ O ₃ or tin (S
n) or a black ITO film formed by doping a small amount of tin using tin oxide SnO ₂ )
A pattern layer 3 and a resin monomer for photo-crosslinking polymerization in which a black pigment (or a dark color pigment such as dark blue) which is laminated in an aligned state on the first pattern layer 3 is dispersed, and a photopolymerization initiator. The second pattern layer 4 is made of a light-shielding photosensitive resin (black photoresist) made of a photosensitive resin (pigment-dispersed photoresist).

The color filter of the present invention, as shown in FIG.
A filter color pattern 5 including e, Green, and Red color patterns is provided. Above the black matrix pattern 2 and the filter color pattern 5, although not shown, a transparent conductive film or the like (a small amount of indium oxide is appropriately included). % Tin-doped ITO film, or the ITO film laminated via a transparent protective layer).

In the color filter of the present invention,
As in the conventional case, the black matrix pattern 2 and the filter color pattern 5 are arranged so as to be in close contact with each other so that no void is formed in the adjacent portion between the black matrix pattern 2 and the filter color pattern 5. And the edge portions of the filter color pattern 5 are adjacent to each other, or the filter color pattern 5 is on the black matrix pattern 2 at least the edge portion thereof, or the filter color pattern 5 if necessary.
Are provided so that they all overlap.

In the color filter of the present invention, the first pattern layer 3 formed of a translucent or opaque indium oxide film, and a black pigment (or a dark blue color or the like) laminated on the first pattern layer 3 in an aligned state. (Dark color pigment)
The black matrix pattern 2 composed of a second pattern layer 4 formed of a light-shielding photosensitive resin made of a photosensitive resin (pigment-dispersed photoresist) in which is dispersed.
In the case of forming a pattern on the glass substrate 1,
This will be described below.

First, ITO (oxide) itself is used as a vapor deposition material or a target on a glass substrate 1 in a low oxygen atmosphere, or indium-trace tin alloy (I
n-Sn) is used as a vapor deposition material or a target in a low oxygen atmosphere in a vacuum vapor deposition system or by sputtering, respectively, to obtain a predetermined film thickness (for example, a vapor deposition film thickness: 500).
A translucent or opaque indium oxide film (or a black (light absorbing) ITO film) having a thickness of Å to 2,000 Å and an optical density of 0.3 to 1.5 is formed.

Subsequently, the formed semi-transparent to opaque indium oxide film (or black (light absorbing) ITO)
Black, dark color pigment on top of the film)
Alternatively, a pigment-dispersed photoresist in which a photosensitive photoresist mainly containing styrene resin (for example, an acrylic polymer and an acrylic monomer and a photopolymerization initiator, or an acrylic monomer and a photopolymerization initiator are contained) is mixed and mixed. A photosensitive resin layer (for example, coating thickness: 0.5 μm to 1 μm, optical density: 0.7 to
2.0 or more). A known photopolymerization initiator can be used.

Next, the photosensitive resin layer is subjected to a pattern exposure (exposure using a master plate such as a photomask) to a shape of a black matrix pattern 2 having an appropriate shape by using a photofabrication (photolithography) method with ultraviolet rays. Alternatively, electron beam exposure) is performed to photopolymerize and cure the exposed region of the photosensitive resin layer with a resin monomer and a photopolymerization initiator to form a cured region in a black matrix pattern.

Subsequently, the unexposed area (uncured area) of the photosensitive resin layer is developed with an organic solvent to form a resist pattern having a shape corresponding to the black matrix pattern 2 (which will later become the second pattern layer 4). Form.

Thereafter, by using the resist pattern as an etching mask, the lower semi-transparent or opaque indium oxide film (or black (light-absorbing) ITO film) is appropriately etched with an etching solution to obtain the structure shown in FIG. As shown, the first pattern layer 3 formed of a translucent or opaque indium oxide film (or a black (light absorbing) ITO film) on the glass substrate 1 is aligned with the first pattern layer 3. Black matrix pattern 2 composed of a second pattern layer 4 formed of a light-shielding photosensitive resin layer formed of laminated pigment dispersion photoresist
Is formed.

In the color filter of the present invention, the second pattern layer 4 applied on the first pattern layer 3 is used.
The pigment-dispersed photoresist as described above can be applied to a thinner film than the applied film thickness of the first pattern layer 3 to the extent that it does not hinder the etching mask.

In the color filter of the present invention,
In the case where the filter color pattern 5 including the blue, green, and red color patterns is formed on a portion of the glass substrate 1 after the black matrix pattern 2 is formed, other than the area where the black matrix pattern 2 is formed, A method similar to the method of forming the filter color pattern of the color filter of, for example, a transparent photosensitive liquid with good dyeability such as gelatin and Blue, Green,
Relief dyeing method using each red dye, and the above-mentioned B
Pigment dispersion photoresist method using each of the pigment dispersion photoresists of blue, green and red, and blue and green
Organic filter color pattern forming method by printing method such as intaglio offset printing method using each of the colored printing inks of reen and Red, or titanium oxide (TiO ₂ , light refractive index;
2.40) and silicon oxide (SiO ₂ , photorefractive index; 1.4
6) Inorganic filter color pattern formation by a dielectric multi-layer film method in which dielectric films such as 6) are vapor-deposited and laminated, and the interference color filters (polarization filters) of Blue, Green, and Red are formed depending on the thicknesses and combinations thereof. According to the method, the black matrix pattern 2 and the filter color pattern 5 are arranged such that their edges are closely adjacent to each other, or the filter color pattern 5 overlaps the black matrix pattern 2 at its edges. 5 is patterned.

An example of the method of forming the black matrix pattern 2 on the glass substrate 1 in the color filter of the present invention will be shown below.

In a magnetron sputtering apparatus equipped with a strong magnetic field cathode of 1200 gauss, targeting indium oxide containing 5% to 10% of tin oxide on the entire surface of the glass substrate 1 (thickness 1.1 mm), 1000 Å thick semi-transparent or opaque by sputtering method
TO thin film (thin film that will later become the first pattern layer, optical density;
0.5 to 1.8, and 1.0 is suitable).

In this case, first, the inside of the chamber is set to 10 ^-6.
After evacuating to about Torr, 2 × 1 argon gas
Sputtering is performed by introducing 0 ^-3 Torr and further introducing oxygen gas at 0.5% of argon gas. The temperature of the glass substrate at this time is room temperature (about 18 ° C. to 25 ° C.).

Next, a black pigment-dispersed photoresist (for example, OFPR; manufactured by Tokyo Ohka Kogyo Co., Ltd., or CK2000; Fuji) in which a black pigment is dispersedly added to a positive type (photolytic type) photoresist on the ITO film. Hunt Co., Ltd.
Manufactured) by a spin coater to a film thickness of 0.5 μm to 1.0 μm.
m (for example, film thickness; 0.6 μm to 0.7 μm, optical density; 1.5 or more is suitable) and dried uniformly, and a light-shielding photosensitive resin layer (layer to be the second pattern layer later) ) Is formed.

The translucent or opaque light-shielding ITO thin film which becomes the first pattern layer and is laminated on the glass substrate 1 in this manner, and the light-shielding photosensitive resin layer which becomes the second pattern layer, respectively. Has a total thickness of 0.7 μm to 0.8 μm
And the total optical density is 2 to 2.5 or more (practical use standard of total optical density; 2).

Next, pattern exposure (mask pattern exposure or beam exposure) is performed on the light-shielding photosensitive resin layer serving as the second pattern layer by ultraviolet rays (or electron beams) corresponding to the black matrix pattern shape to obtain black. A portion other than the matrix pattern corresponding portion is exposed to alkali to make it soluble, and the exposed portion is removed by developing with an alkali solution such as sodium hydroxide, and the black matrix pattern shape corresponding to the black matrix pattern shape is formed on the light-shielding photosensitive resin layer. A resist pattern is formed. As the photoresist for the resist pattern, a negative type (photo-curing type) photoresist can be used.

Next, using this resist pattern as an etching mask, black ITO serving as a lower first pattern layer is formed.
By pattern etching the film with ferric chloride solution or sodium thiocyanate and sodium formate,
The part without etch mask is removed by etching,
A black matrix pattern composed of a first pattern layer 3 made of a black ITO film on a glass substrate 1 and a second pattern layer 4 made of a light-shielding photosensitive resin layer laminated on the first pattern layer 3 in alignment with each other. Form 2.

Thereafter, the black matrix pattern 2 formed on the glass substrate 1 is exposed to 120 ° C. to 250 ° C.
By heating for 10 minutes to 60 minutes, the second pattern layer 4 formed of the light-shielding photosensitive resin layer is subjected to a baking treatment to impart chemical resistance.

Next, a red (Red) ink is used between the black matrix patterns 2 by a printing method to make a red.
A colored pattern R is formed. In the same way, blue (Blu
e) A blue color pattern B and a green color pattern G are sequentially formed by a printing method using an ink and a green ink to form a filter color pattern 5.

Finally, if necessary, an acrylic resin (or urethane resin, epoxy resin, silicone resin, etc.) is used to form a transparent protective layer on the entire surface of the filter color pattern 5 by coating, and the ITO is formed. A transparent conductive film such as a film (indium oxide doped with tin) is formed.

[0031]

The color filter of the present invention comprises a glass substrate,
Dispersing a first pattern layer 3 formed of a semitransparent or opaque indium oxide film (or a black (light absorbing) ITO film) and a black pigment that is laminated on the first pattern layer 3 in alignment. Since the black matrix pattern 2 having the two-layer structure of the second pattern layer 4 formed of the light-shielding photosensitive resin layer is provided, the light-shielding property of the black matrix pattern 2 is the same as that of the first pattern layer 3. It is possible to obtain the sum of the film thicknesses of the second pattern layer 4 and to set the single-layer film thickness of each of the first pattern layer 3 and the second pattern layer 4 to be smaller than the conventional one.

The semi-transparent or opaque indium oxide film or the black ITO film of the first pattern layer 3, which is the lower layer, has a light-shielding property, so that the film thickness of the photosensitive resin layer of the upper second pattern layer 4 is large. Even when the film thickness is set to a relatively small value that can withstand as an etching mask, sufficient light shielding property and light absorbing property as the black matrix pattern 2 can be obtained.

[0033]

EFFECT OF THE INVENTION The color filter of the present invention allows the color pigment dispersed photoresist to be set as thin as possible when forming a black matrix pattern by a photofabrication (photolithography) method. It is possible to eliminate the lengthening of the exposure time for the exposure, which can eliminate the occurrence of halation on the glass substrate surface, and improve the accuracy of the black matrix pattern edge portion.
By making it possible to set the film thickness of the color pigment-dispersed photoresist to be small, it is possible to eliminate the conventional generation of protrusions.

Further, when incorporated into a liquid crystal display device, it has a low reflectance to external light, so that it has the effect of improving the visibility, and the formation of an indium oxide film by vacuum vapor deposition or sputtering according to the present invention. Has an effect that the manufacturing cost can be reduced because the film forming speed is faster than the film forming by vacuum vapor deposition or sputtering of chromium or chromium oxide.

[Brief description of drawings]

FIG. 1 is a side sectional view illustrating a black matrix pattern in an embodiment of a color filter of the present invention.

FIG. 2 is a side sectional view illustrating a black matrix pattern and a filter color pattern in one embodiment of the color filter of the present invention.

3A is a side sectional view illustrating a black matrix pattern in a conventional color filter, and FIG. 3B is a side sectional view illustrating a black matrix pattern and a filter color pattern in a conventional color filter.

[Explanation of symbols]

1 ... Glass substrate 2 ... Black matrix pattern 3
... 1st pattern layer 4 ... 2nd pattern layer 5 ... Filter color pattern 11 ... Glass substrate 12 ... Black matrix pattern 13 ... 1st pattern layer 14 ... 2nd pattern layer 15 ... Filter color pattern

Claims (1)

[Claims] 1. A black matrix pattern 2 on a glass substrate 1, a filter color pattern 5 composed of blue, green, and red coloring patterns, a transparent conductive film, and the like. The black matrix pattern 2 is semitransparent or transparent. The first pattern layer 3 is made of opaque indium oxide, and the second pattern layer 4 is made of a light-shielding photosensitive resin and laminated on the first pattern layer. A color filter characterized in that