JPH03274502A - Color filter - Google Patents

Abstract

PURPOSE:To improve heat resistance and light resistance by using a pigment resist containing pigment and acrylic resin so that a color filter layer may be formed. CONSTITUTION:This color filter is provided with a transparent substrate 1, a light shielding layer 2 consisting of an opaque metallic layer formed in a lattice state on one surface and a photoresist layer 3 left and arranged on the upper surface of the layer 2. Then, it is constituted of the color filter layers of red R, green G and blue B using the pigment resist, which are formed, at least, to fill up a gap between the lattices of the layer 2, and an overcoat layer 4 which is formed to wholly cover the color filter layer and the layer 2. The color filter layers R, G and B are formed of the pigment resist which is principally composed of the acrylic resin, the pigment, dispersant and solvent. Thus, the heat resistance and the light resistance are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a color filter used in color liquid crystal display devices and the like.

[Prior Art] In a color liquid crystal display device, a color filter layer is formed on the inner surface of one of the glass substrates disposed opposite to each other in order to prevent deterioration of display quality.

Conventionally, the method for forming this color filter layer was performed as follows. That is, a hydrophilic resin solution such as gelatin, green casein, or polyvinyl alcohol made photosensitive with dichromate is coated on the entire surface of a transparent substrate such as a glass plate by a spin coating method, and then by a mask exposure method. A predetermined pattern is printed, exposed, and developed to form a relief pattern, which is dyed with an acid dye of a desired color, and then resist-dyed with an aqueous solution of tannic acid and an aqueous solution of tartarite. This process is repeated for the number of colors to create color filter sections. Furthermore, in order to improve display quality as a liquid crystal display, a grid-like or line-like light-shielding black matrix is formed at the boundary between each color section before or after forming the color filter section. For forming this light-shielding pattern, a relief pattern is formed by photolithography in the same manner as the color filter section, and this is dyed with black dye.

[Problems to be Solved by the Invention] According to the conventional method of forming a color filter layer as described above,
Since the part to be dyed is made of natural materials, there was a problem of low heat resistance. Furthermore, since dyes were used, there was also the problem of low light resistance.

The present invention was made based on this viewpoint, and an object of the present invention is to provide a color filter with excellent heat resistance and light resistance.

[Means for Solving the Problems] In order to achieve the above object, the color filter of the present invention includes a transparent substrate, a light shielding layer made of an opaque metal layer patterned on one surface of the substrate, A black photoresist layer left on the light-shielding layer, and red, green, and blue color filter layers using pigment resist formed at least to fill in the space between the light-shielding layers. Features.

In a desirable embodiment, the opaque metal layer is Cr, AI
! , and Cu, and the light-shielding layer is formed by photolithography. Preferably, the pigment resist is a photocurable coloring composition containing an acrylic resin, an organic dye, a dispersant, and a solvent as main components. Preferably, a transparent overcoat layer is further provided on the entire surface.

[Function] The pigment resist forming the color filter layer has excellent heat resistance, light resistance, etc., and this makes it possible to provide a color filter with high definition and long life.

The combination of the opaque metal light-shielding layer and the black photoresist layer enhances the light-shielding properties of the area and reduces the influence of pinholes generated in the metal light-shielding layer.

[Example] FIG. 1 schematically shows a cross section of an example of a color filter according to the present invention, which consists of a transparent substrate 1 and an opaque metal layer formed in a grid pattern on one surface of the transparent substrate 1. A light-shielding layer 2, a photoresist layer 3 left on the upper surface of the light-shielding layer 2, and a pigment resist formed so as to fill at least the lattice spaces of the light-shielding layer 2. Red R1 Green G and Blue B colors are used. It consists of a filter layer and an overcoat layer 4 formed to cover the entire color filter layer and light shielding layer 2.

The transparent substrate 1 is made of glass, for example. The light shielding layer 2 is made of, for example, Cr, Aj7. It consists of Cu etc. Photo 1 Nodist layer 3
The photoresist layer contains a black colorant.

The color filter layers RSG and B are formed from a pigment resist whose main components are an acrylic resin, a pigment, a dispersant, and a solvent.

The role of the acrylic resin in the pigment resist is to fix the pigments of each color onto the transparent substrate, and also to enable patterning in any shape as required.

Pigments of each color play the role of decomposing white light, so they must have excellent transparency, light resistance, and heat resistance. The primary particle size of the pigment is 0.3 μm or less, preferably 0.1 μm or less.
It is smaller than μm and is sufficiently small compared to the wavelength of visible light. Furthermore, organic pigments are desirable as pigments with excellent transparency.

The dispersant is added to prevent pigment agglomeration and to uniformly disperse the pigment in the acrylic resin. Therefore, the dispersant must also have heat resistance and must not impair the properties of the color filter. It has been found that organic pigment conductors of pigments are extremely effective as dispersants that meet this purpose. Of course, the dispersant is not limited to the derivatives of the pigment, and may include cationic activators, anionic activators, etc.
, nonionic activators, etc. can also be applied.

As a solvent, methyl cellosolve, ethyl cellosolve,
Cyclohexanone, xylene, etc. are preferred, and mixtures of these solvents may also be used, but cyclohexanone and methylcellosalb are particularly preferred from the viewpoint of solubility.

The weight ratio of pigment to 1 part of acrylic resin is usually 0.25.
The range of 3 to 3 is preferable. Lowering the pigment ratio improves the properties as a filter, but in order to obtain a predetermined optical density, it is necessary to increase the film thickness, making microfabrication difficult. When the proportion of pigment is increased, the dispersibility and coating properties of the pigment are significantly deteriorated. The weight ratio of dispersant to pigment is 0
．． 01 to 0.2 is preferable, but it is not necessarily limited to this value. The film thickness of the color filter with the above formulation was 0.75 μm to 3.0 μm.

There are two ways to impart photocurable properties to the colored composition of the present invention: a crosslinking method and a polymerization method. Various azide compounds can be used as the crosslinking agent when curing by the crosslinking method. Furthermore, in the case of curing by a polymerization method, there are many commercially available additives such as monomers and polymerization initiators.

Next, a method for manufacturing the above color filter will be explained.

First, as shown in FIG. 2, one surface of the transparent substrate 1 is coated with a thickness of, for example, 500 to 200 nm by vapor deposition, sputtering, or the like.
A uniform opaque metal film 2a with a thickness of 0.000 μm is formed over the entire surface. Next, a photoresist is uniformly applied to the upper surface using a spinner or a roll coater, dried, and then exposed and developed by a mask exposure method to form a black photoresist layer 3 in a predetermined pattern.

Next, using this photoresist layer 3 as a mask, the exposed portions of the metal film 2a are removed by etching to form a light shielding layer 2 in a lattice pattern as shown in FIG. Next, the photoresist layer 3 is heat-treated at a temperature of 200° C. or higher to impart sufficient chemical resistance to the photoresist layer 3.

Next, as shown in FIG. 4, a red pigment resist is applied to the entire substrate using a spinner roll coater or the like. Next 230
The solvent is removed at a temperature below .degree. C. to form a dry film of the colored resist. Next, this film is partially exposed to light through a predetermined mask and developed to form a red color filter layer R at a predetermined portion between the light shielding layers 2.

Similarly, as shown in FIGS. 5 and 6, color filter layers G and B are sequentially formed at predetermined positions using a green pigment resist and a blue pigment resist.

Finally, as shown in FIG. 1, the entire surface is coated with an overcoat layer 4 using a transparent material such as acrylic resin, urethane resin, epoxy resin, silicone resin, etc.
A color filter is created by flattening the surface irregularities.

[Effects of the Invention] According to the present invention, by using a pigment resist containing a pigment and an acrylic resin to form a color filter layer, a high-definition color filter with excellent heat resistance and light resistance is created. can do.

Furthermore, the combination of the light-shielding layer made of opaque metal and the black photoresist layer left thereon provides extremely good light-shielding properties in the area.

Moreover, since the photoresist layer remains, the influence of pinholes generated in the metal light-shielding layer is also reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment of a color filter according to the present invention, and FIGS. 2 to 6 are cross-sectional views showing an example of manufacturing the embodiment shown in FIG. 1 in the order of steps.

Claims (5)

[Claims] (1) A transparent substrate, a light-shielding layer made of an opaque metal layer patterned on one surface of the substrate, a black photoresist layer left on the light-shielding layer, and at least a lattice gap of this light-shielding layer. A color filter comprising red, green, and blue color filter layers using embedded pigment resists. (2) The color filter according to claim 1, wherein the light shielding layer is formed by a photolithography method. (3) The color filter according to claim 1, wherein the opaque metal layer contains a metal selected from Cr, Al, and Cu as a main component. (4) The color filter according to claim (1), further comprising a transparent overcoat layer on the entire surface. (5) The color filter according to claim 1, wherein the resist is a photocurable coloring composition containing an acrylic resin, an organic dye, a dispersant, and a solvent as main components.