JPH05297211A - Manufacture of light-shielding layer of color filter for liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide a color filter for a liquid crystal display element that is inexpensive, highly accurate, and excellent in contrast by coating a dye-affinity medium layer having a photosensitive property, and by exposing from the rear side of the base plate on which picture elements have been formed so as to form a dye-affinity medium layer only between picture elements. CONSTITUTION:After picture elements of three primary colors of red, green, and blue have been formed on the surface of a light-transmitting base material by means of a pigment dispersed polymer composition, a dye-affinity medium layer having photosensitivity is coated thereon, and then exposure and development are selectively carried out from the rear side of the base plate on which picture elements have been formed to form a dye-affinity medium layer only between the picture elements, and consecutively the dye-affinity medium layer is colored with a light absorbent dye to form a light-shielding layer. The dye-affinity medium layer to be used requires characteristics such as coating-formability, pattern workability, dye-affinity, chemical resistance, heat resistance, or the like. A photosensitive composition in which bichromate is mixed in a natural polymer such as collagen and gelatin, and a photosensitive composition in which bichromate is mixed in a water soluble polymer in which polyvinyl alcohol or the like are synthesized are suitable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a color for a liquid crystal display device.
The present invention relates to a method for easily and highly accurately manufacturing a light shielding layer provided between pixels of a filter. (EN) A color filter for a liquid crystal display device having good contrast by forming a light-shielding layer of the present invention after colored pixels of three primary colors of RGB are formed by a pigment dispersion method.

[0002]

2. Description of the Related Art A light-shielding layer provided between pixels of a color filter for a liquid crystal display element is generally called a black matrix, but it is usually formed by etching a metal chromium deposition film or a sputtering film. It is essential to produce a chromium thin film uniformly and without defects such as pinholes, and patterning requires processing steps such as resist coating, exposure / development, baking, etching, and resist stripping. ..

There has been an attempt to manufacture these light-shielding layer patterns using a photosensitive resist material containing a visible light-shielding (black) material, but it is compatible with high light-shielding effect and high sensitivity and high resolution. It's hard to do. A method has been proposed in which an ink containing a photosensitive or non-photosensitive material that blocks visible light (black) is applied by a printing method, but it is very difficult to form a pattern of 10-50 μm size. Have difficulty.

In some color filters used in STN type liquid crystal display elements, this light shielding layer is formed by a color superimposing method, but a black pattern which is expected to have a sufficient light shielding effect from the demand for quality improvement. Formation is desired.

[0005]

In the present invention, after the pixels of three colors of red, green and blue formed by the photolithography method using a pigment dispersion paste are arranged, the entire surface is exposed to light. The dyeable medium layer having the dye is applied, and the dyeable medium layer is exposed only from the back side of the substrate on which the pixels are formed to form a dyeable medium layer between the pixels.
A light-shielding layer which is made into a transparent film is formed to inexpensively and highly accurately manufacture a color filter for a liquid crystal display device having an excellent contrast.

[0006]

According to the present invention, a pixel having three primary colors of red, green and blue is formed with a pigment-dispersed polymer composition on the surface of a light-transmitting substrate, and then a dye having photosensitivity is formed on the pixel. Of the dyeable medium layer, and then selectively exposing and developing from the back side of the substrate on which the pixels are formed to form the dyeable medium layer only between the pixels, and then the dyeable medium layer is exposed to visible light. The present invention relates to a method for producing a light-shielding layer of a color filter for a liquid crystal display device, which comprises dyeing with an absorptive dye to form the light-shielding layer.

A color filter for a liquid crystal display element is an essential member for colorizing a liquid crystal display element, and is formed by forming colored pixels on a glass or transparent plastic substrate. Red (R), green (G), and blue (B) pixels of the three primary colors are arranged in a line or mosaic, and the size is 100.
It is around μm. In order to increase the contrast of an image, a light-shielding portion is formed between each pixel so as to shield a transistor and a wiring portion in the active matrix driving method. This is usually called a black matrix. The black matrix is made in a stripe shape, a mosaic shape, a lattice shape, etc. according to the arrangement of each pixel of RGB, but the width is a few μm in a narrow place and about 100 μm in a wide place. Become.

Since a high light-shielding property and a highly precise pattern forming property are required, a thin film of metallic chromium is currently produced by etching. The method of forming the pixel parts of the three primary colors of RGB on the substrate on which the black matrix is formed is as follows.
Dyeing methods, pigment dispersion methods, electrodeposition methods, printing methods, etc. have been proposed.

The present invention relates to a method for producing a patterned light-shielding layer, which is indispensable for improving the quality of color filters, more simply, efficiently, and highly accurately.

The light transmissive substrate used is glass or a transparent plastic sheet. Although various methods for forming colored pixels have been devised, the preferred one for the present invention is one in which a pigment is used as a coloring component, and a manufacturing method thereof is a printing method,
It is called an electrodeposition method or a pigment dispersion method. The pigment dispersion method uses a paste in which an organic pigment is mixed with a photosensitive or non-photosensitive composition containing a polymer as a binding component and subjected to dispersion treatment. A photosensitive material forms pixels by its own photolithography, but a photoresist is used for forming pixels of a non-photosensitive material. These compositions mainly include an organic pigment having a polymer material as a binding component, and as the polymer, a polyimide having excellent heat resistance, an acrylic polymer having excellent transparency, a polyvinyl alcohol type, or the like is used. However, it is not limited to these as long as the color filter characteristics such as transparency, heat resistance and chemical resistance are satisfied. Color pastes containing these polymers and organic pigments as essential components,
Although it may be non-photosensitive or photosensitive, known methods can be applied to make it photosensitive.

Pixel formation using a photosensitive color paste is performed in the following procedure. A coating film having a thickness of about 2 μm is formed on the substrate by using a dip method, a coater such as a roller coater, and a spin coater such as a holer and a spinner. After drying and pre-baking, it is exposed through a mask having a pixel pattern and developed to form a pixel pattern, which is post-baked.
Then, the formation of the pixel of the first color is completed. This operation is repeated for the pixels of the second and third colors. The method of the present invention is applied starting from a state in which predetermined pixels having a pigment as a coloring material are formed on the surface of a light-transmitting substrate obtained by such a photolithography method, a printing method, or an electrodeposition method. It

The dyeable medium layer used here is required to have characteristics such as coating film forming property, pattern processability, dyeing property, chemical resistance and heat resistance. A photosensitive composition or polyvinyl in which a dichromate is blended with a natural polymer such as collagen, gelatin, glue, and casein which has been used for producing a small liquid crystal color TV or a color filter for an image pickup tube. A photosensitive composition in which dichromate is mixed with a synthesized water-soluble polymer such as alcohol or polyvinylpyrrolidone,
It is a material having excellent film forming properties, patterning processability, dyeability, etc., and is also suitable as a material used for the purpose of the present invention. For example, an aqueous solution prepared by mixing and dissolving gelatin / dichromate is prepared, and this is applied by spin coating such as a spinner or by means such as a roll coater to form a coating film on the pixel formation surface. The composition is irradiated with light to be cured to have a three-dimensional structure in order to maintain the shape of the coating film during dyeing and to improve durability such as heat resistance of the film itself. This has a negative effect on dye dyeing, but is necessary from the viewpoint of maintaining the shape of the film during dyeing. The dyeing is mainly performed using an acid dye. Since it is preferable that the deep dyeing can be performed quickly, the degree of curing before dyeing can be controlled.

Since collagen, gelatin, casein, gluer, etc. are used in the dyeable medium layer, the dye is mainly a water-soluble dye having a sulfonic acid group or a carboxylic acid group in the molecule. In terms of chemical structure, azo series, anthraquinone series,
Examples include triphenylmethane type and xanthene type. Dyeing is generally carried out in an acid bath. Metal complex dyes are also included in these categories. After dyeing, a fixing process can be performed for fixing the dye. When the protective layer is provided on the surface layer including the pixels, it is not always necessary.

A polymer having a dyeable site in its main chain or side chain can also be used in the dyeable medium layer. Polymers of various structures can be synthesized or used. For example, a water-developable acrylic negative resist having a dyeable group, a hydrophilic group and a hydrophobic group can be used. These are coated with an organic solvent. For the photosensitivity, a method of forming a three-dimensional structure by a reaction of a cross-linking type or a polyfunctional monomer is adopted. Moreover, you may use these methods together.

Further, it is also possible to use a polymer in which the photosensitive group of the side chain contains a dyeable group and a component which causes a dimerization reaction such as a chalcone group, a cinnamyl group and a stilbazolium group.

Acid dyes are suitable for the purpose of the present invention because they have good heat resistance and light resistance. However, in the case of dyeing with an acid dye, the dyeable group may be an amino group, an amide group, an ammonium salt or the like. Owning is a requirement. Curing by back exposure so that only the dyeable medium layer between pixels remains on the substrate,
The uncured part is removed. Since the pixel portion blocks ultraviolet rays, the dyeable medium layer coated on the pixel surface is an uncured material and is removed by treatment with an aqueous developer. If the pixel is not sufficiently shielded from ultraviolet rays, it is preferable to use a wavelength selective filter for exposure.

The dyeable medium layer can be made to absorb visible light by dyeing, but it does not prevent photocuring of the dyeable medium layer between pixels in order to obtain a high level of visible light blocking property. Additives can be added in advance to a degree. These additives can be selected from inorganic or organic color pigments, extender pigments, white pigments, metal powders, polymer powders and the like.
From the viewpoint of shading, black pigments (carbon black, aniline black, cyanine black, etc.) are expected to be most effective, but the amount added is selected within a range that does not impair the resistance value or photosensitivity of the film. It Besides blocking absorption of visible light, scattering and reflection are also effective, and white pigments such as titanium oxide and zinc white can be added. Similarly, extender pigments such as talc, alumina and kaolin also have a shielding effect. Metal powders such as aluminum, bronze and tin and polymer powders such as polyethylene and polypropylene are also effective, but the amount to be added is limited. These are added in consideration of synergistic effects on the effect of dyeing, and a material having a dyed site is more preferable.

A substrate having a dyeable medium layer formed between pixels is dipped in a dyeing bath and dyed with a visible light absorbing dye at an appropriate temperature and time. At this time, since the pixel portion is a photo-cured or heat-cured film and has high acid resistance and chemical resistance, it is not contaminated with dyes. Therefore, dyeing of the dyeable medium layer can be applied under fairly strong conditions.

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

[0020]

【Example】

Example 1 On a glass substrate having pixels of three primary colors of red, green and blue prepared using a photosensitive color paste containing an acrylic polymer as a binding component, dichromic acid was added to an aqueous solution containing 20 wt% of gelatin component. An aqueous solution of ammonium was added, and the solution was spin-coated so that the gelatin component in the solution was 15 wt% and the ammonium dichromate was 0.75 wt%. As a result of drying for 1 hr in an oven at 100 ° C., a transparent thin film with a film thickness of 1.5 μm was formed between the pixels. Ultraviolet light of an ultra-high pressure mercury lamp was irradiated from the back side of the glass substrate using the pixel portion as a mask to make it insoluble in water by utilizing the photosensitivity of gelatin / ammonium dichromate between pixels. The gelatin component attached on the pixels can be removed by washing with water. A substrate having a dyeable medium layer made of gelatin, which is hardened between pixels, produced by the above operation is used as an acid dye "Aminyl-F" manufactured by Sumitomo Chemical Co., Ltd.
The black Black F-SGL of was dissolved and dyed by immersing it in an aqueous solution containing acetic acid and a small amount of ionic surfactant ammonium polyoxyethylene sulfonate at 60 ° C. After the substrate was pulled up from the dye solution, it was washed with water and treated with tannic acid to fix the dye. The visible light transmittance of the portion of the gelatin dyeable medium layer dyed with this black dye was 5% or less.

Example 2 On the same pixel forming glass substrate as in Example 1, 10 wt% of the organic pigment phthalocyanine blue (PB15) was added to the gelatin component.
In the same manner as in Example 1 except that was added, a light-shielding layer made of a colored gelatin film was formed between pixels. The optical density of this light shielding layer was about 2 (transmittance 1%).

Example 3 A colored paste was prepared by dispersing organic pigments of three primary colors in a solution of polyamic acid. The colored paste was applied to a glass substrate, and the pixels were patterned by an etching method using a positive resist. went. The patterned pigment / polyamic acid film layer was heat treated at 250-300 ° C. for imidization to form pigment / polyimide pixels. Repeat this operation,
Pixels of three primary colors were produced.

As a polymer having dyeability with an acid dye and negative photosensitivity, J. Photopolym. Sci. Technol., Vol. 3,
A copolymer having a chalcone group and a tertiary dimethylamino group in its side chain was produced according to the method described in No. 2, p.168-172 (1990). A solution of this copolymer in ethyl cellosolve is applied on the pixel formation substrate, dried, and then exposed to an ultra-high pressure mercury lamp from the back side of the substrate to cure it. The pixel formation surface was washed with. The dyeing was performed under the same conditions as in Example 1. After thoroughly washing with water, heat treatment was performed at 200 ° C for 1 hr. The transmittance of the obtained light shielding layer was 1.6%.

Example 4 In Example 3, organic pigments PR-177 and PB-15 were preliminarily added to the polymer solution of the dyeable medium layer in a ratio of 1: 1 to 10 wt% of the weight of the polymer.
In addition, the same process was performed. The transmittance of the obtained light shielding layer was 0.5%.

[0025]

Since the present invention is constructed as described above, it is possible to form a light-shielding layer easily and with high accuracy, and it is possible to easily manufacture a color filter.

Claims (4)

[Claims] 1. A surface of a light-transmitting substrate is formed with pixels of three primary colors of red, green, and blue by a pigment-dispersed polymer composition, and then a dyeable medium layer having photosensitivity is coated thereon, and then. Selectively expose and develop from the back side of the substrate on which pixels are formed to form a dyeable medium layer only between pixels, and then dye the dyeable medium layer with a visible light absorbing dye to block light. A method for producing a light-shielding layer of a color filter for a liquid crystal display element, which comprises forming a layer. 2. A dichromate is added to at least one water-soluble resin selected from the group consisting of collagen, gelatin, glue, casein, polyvinyl alcohol and polyvinylpyrrolidone for the dyeable medium layer. It is a photosensitive composition, The manufacturing method of the light shielding layer of the color filter for liquid crystal display elements of Claim 1 characterized by the above-mentioned. 3. The colorant for a liquid crystal display device according to claim 1, wherein the dyeable medium layer is a photosensitive composition containing a synthetic polymer as a main component having a dyeing site on a main chain or a side chain. −
A method of forming a light shielding layer of a filter. 4. A photosensitive dyeable medium layer to be coated contains one or more components selected from inorganic or organic color pigments, extender pigments, white pigments, metal powders and polymer powders. A method for producing a light-shielding layer of a color filter for a liquid crystal display device according to claim 1.