JPH11149259A - Color filter - Google Patents

Abstract

(57) [Problem] To provide a reflection type color filter having a high reflectance and extremely small irregular reflection. SOLUTION: A color filter composed of a plurality of colored patterns is provided on a reflective layer provided on a substrate via a light-transmitting protective film to form a color filter, and a light-transmissive protection positioned between the reflective layer and the colored layer is provided. The film prevents the erosion of the reflective layer by the developer during the formation of the colored layer.
Prevents the generation of residues of the photosensitive coloring material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color filter, and more particularly to a color filter for a reflection type liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, a color liquid crystal display device has attracted attention as a flat display. The color liquid crystal display device is classified into a reflection type and a transmission type. A reflection type color liquid crystal display device generally has a plurality of colors (usually three primary colors of red (R), green (G), and blue (B)) on a reflection layer made of a metal such as aluminum provided on a substrate. A color filter having a coloring layer made of (including a black matrix and a flattening layer as necessary) and a thin film transistor (T
A TFT array substrate provided with an FT element is attached to the substrate with a predetermined gap therebetween, and a liquid crystal material is injected into the gap.

The above-described color filter used in a reflection type color liquid crystal display device is, for example, formed by forming a reflection layer on a substrate, applying a photosensitive coloring material on the reflection layer, and forming a predetermined photo-resist. After exposure through a mask, development is performed to form a colored pattern, and such an operation is performed in red (R),
It is produced by repeating three colors of green (G) and blue (B), and four or five colors including a black matrix and a flattening layer as necessary.

[0004]

However, in the conventional color filter for a reflection type color liquid crystal display device, there is a problem that the reflectance of the reflection layer is insufficient and a clear display image cannot be obtained. This is because, in the developing step after exposing the photosensitive coloring material layer applied on the reflective layer as described above, the reflective layer made of a metal material such as aluminum is eroded by the developer, and the reflectance of the reflective layer is reduced. It is caused. In addition, since the metal material constituting the reflective layer has high adhesion to the photosensitive coloring material, unnecessary photosensitive coloring material remains on the reflective layer after development, and the residue causes irregular reflection to reduce image quality. There was also the problem of adverse effects.

The present invention has been made in view of the above circumstances, and has as its object to provide a reflection-type color filter having a high reflectance and extremely little irregular reflection.

[0006]

In order to achieve such an object, a color filter according to the present invention comprises a substrate, a reflective layer provided on the substrate, and a light-transmitting protective film on the reflective layer. And a colored layer composed of a plurality of colored patterns.

The light-transmitting protective film may be a thin film made of an inorganic oxide, the light-transmitting protective film may be a thin film made of an organic resin, or the reflective layer may be made of a metal material. Wherein the light-transmitting protective film is a thin film made of a metal oxide formed by treating the surface of the reflective layer.

[0008] Further, a structure is provided in which a flattening layer covering the coloring layer is provided.

In the present invention as described above, the light-transmitting protective film located between the reflective layer and the colored layer prevents the reflective layer from being eroded by the developing solution at the time of forming the colored layer, and the light-transmitting protective film is formed. Shows low adhesion to the photosensitive coloring material.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.

FIG. 1 is a schematic longitudinal sectional view showing one embodiment of the color filter of the present invention. The color filter 1 shown in FIG. 1 includes a reflective layer 3 formed on a substrate 2 and a colored layer 5 formed on the reflective layer 3 with a light-transmitting protective film 4 interposed therebetween.
The coloring layer 5 includes a red coloring pattern 5R, a green coloring pattern 5G, and a blue coloring pattern 5B.

The substrate 2 includes various glass substrates, metal substrates,
A resin substrate, a composite substrate made of two or more of these materials, or the like can be used.
It can be appropriately set in consideration of the use of, for example,
It can be about 0.3 to 10 mm.

The reflecting layer 3 is made of aluminum, chromium, gold,
It is formed of a thin metal film such as silver or copper and has a thickness of 500 to 100.
The angle can be set in the range of 00 °, preferably 1000 to 3000 °. Such a reflective layer 3 can be formed by a known thin film forming method such as an evaporation method, a sputtering method, a CVD method, and an ion plating method.

In the light-transmitting protective film 4, the reflection layer 3 is eroded by a developing solution used in a developing step after exposing the photosensitive coloring material in the stage of forming the coloring layer 5, and the reflectance is lowered. And to prevent the photosensitive coloring material from remaining in the region where the coloring layer 5 is not formed. This light-transmitting protective film 4 is made of SiO ₂ , Al ₂ O ₃
, MgO, In ₂ O ₃ , SnO ₂ , Ta ₂ O ₅ , Y ₂
A thin film of an inorganic oxide such as O ₃ , PbTiO ₃ , ZnO, ITO (indium tin oxide), an acrylic resin, an epoxy resin, a vinyl ether resin, a polyimide resin,
A thin film made of an organic resin such as a propynyl-based resin, and
Γ-A generated by processing the surface of the above-mentioned reflective layer 3
It may have a single-layer structure made of a thin film of a metal oxide film such as l ₂ O ₃ or Cr ₂ O ₃ , or a multi-layer structure made of the same or different materials.

The light-transmitting protective film 4 made of the above-mentioned inorganic oxide thin film is formed by a resistance heating evaporation method, a sputtering method, an EB method, or the like.
It can be formed by a vacuum evaporation method, a thermal CVD method, a plasma CVD method, an ion plating method, or the like, and has a thickness of 5
It can be set in the range of 0-10000 °, preferably 100-3000 °. The light-transmitting protective film 4 made of the above-mentioned organic resin thin film can be formed by applying an organic resin material, drying and curing, and has a thickness of 0.1 to 3.0 μm, preferably 0.1 to 3.0 μm. 2 to 1.0 μm
Can be set in the range. Further, the light-transmitting protective film 4 made of the above-mentioned metal oxide thin film can be formed by treating the surface of the reflective layer 3 with sulfuric acid or the like or by performing anodizing treatment, and has a thickness of 50 to 10000Å. , Preferably in the range of 100 to 1000 °.

The coloring layer 5 can be formed by a pigment dispersion method using a photosensitive coloring material obtained by adding a coloring material to a known positive or negative photosensitive resist. That is, a desired photosensitive coloring material is applied on the light-transmitting protective film 4, and the applied film is exposed through a predetermined photomask, and then unnecessary portions are removed using a developing solution to form a pattern. Can be formed.

Since the color filter 1 of the present invention is provided with the light-transmitting protective film 4 on the reflective layer 3 as described above, the reflective layer 3 is eroded by the developer used in the developing step, for example, alkali. Corrosion of the aluminum reflective layer by the developer does not occur. Therefore, the reflection layer 3 of the color filter 1 of the present invention is maintained at a high reflectance state. Further, the light-transmitting protective film 4 is
Has low adhesion to the photosensitive coloring material, and can effectively prevent unnecessary photosensitive coloring material after exposure from remaining in the stage of forming the coloring layer 5. Therefore, the color filter 1 of the present invention has very little irregular reflection.

The color filter according to the present invention has a color layer 5
May be provided with a black matrix so as to be located between the respective colored patterns constituting. In this case, the black matrix is formed on the substrate 2, the one formed on the reflective layer 3, the one formed on the light-transmitting protective film 4, and the one formed on the boundary between adjacent colored patterns. Any of these may be used, and can be formed of a light-shielding resin or a metal such as chromium.
However, when a black matrix is formed by exposure and development using a photosensitive light-shielding resin, the black matrix is formed directly on the substrate 2 in order to prevent erosion of the reflective layer 3 by a developer, or After forming the light-transmitting protective film 4, it is necessary to form a black matrix.

Further, the color filter of the present invention may include a flattening layer 6 which covers the coloring layer 15 as shown in FIG. The flattening layer 6 can be formed using, for example, an organic resin such as an acrylic resin, an epoxy resin, a vinyl ether resin, a polyimide resin, or a propynyl resin, and the light-transmitting protective film 4 is made of an organic resin. When formed, it is preferable to use a similar organic resin.

[0020]

Next, the present invention will be described in more detail with reference to examples.

As a substrate, a glass substrate having a thickness of 1.1 mm (7059 glass manufactured by Corning Incorporated) was prepared. An aluminum reflective layer (thickness 3) was formed on this substrate by vacuum evaporation.
000 °).

Next, a light-transmitting protective film (thickness: 3) made of SiO _{2 is formed} on the aluminum reflective layer by sputtering.
00Å).

Next, a photosensitive coloring material for red coloring pattern (CR-2 manufactured by Fuji Hunt Co., Ltd.) is formed on the light transmitting protective film.
000) by spin coating, exposing the coating film through a predetermined photomask, and then developing using a developer (exclusive developer CD manufactured by Fuji Hunt Co., Ltd.). For 60 minutes to cure the colored layer to form a red colored pattern.

Further, a photosensitive coloring material for green coloring pattern (CG-2000 manufactured by Fuji Hunt Co., Ltd.) and a photosensitive coloring material for blue coloring pattern (CB-2000 manufactured by Fuji Hunt Co., Ltd.) are used. A green color pattern and a blue color pattern were formed in the same manner as described above to obtain a color filter (Example 1).

Also, instead of forming a light-transmitting protective film made of SiO ₂ , an acrylic resin (Hitachi Chemical Co., Ltd.
P-1008-IM1) was applied and cured to form a light-transmitting protective film (thickness: 0.8 μm).
In the same manner as in the above, a color filter (Example 2) was produced.

Further, instead of forming the light-transmitting protective film made of SiO ₂ , the surface of the aluminum reflective layer is oxidized by anodizing to form a light-transmitting protective film (thickness) of γ-Al ₂ O _3. A color filter (Example 3) was fabricated in the same manner as in Example 1 except that the thickness of the color filter was 300 °).

On the other hand, for comparison, a color filter (Comparative Example 1) was produced in the same manner as in Example 1 except that the light-transmitting protective film was not formed.

With respect to the color filters (Examples 1 to 3 and Comparative Example 1) thus manufactured, the reflectance of the aluminum reflective layer was measured by the following method.

Method for measuring reflectance AO-2 spectrophotometer manufactured by Olympus Optical Co., Ltd.
The measurement was carried out in a reflection measurement mode using.

As a result of the measurement of the reflectance, the color filters of the present invention (Examples 1 to 3) exhibited a reflectance of 98% in the wavelength region of 400 to 700 nm in the region where the colored layer was not formed.
As described above, the degree of occurrence of irregular reflection is extremely low, and it has been confirmed that the color filter can be sufficiently practically used as a color filter for a reflection type liquid crystal display device.

On the other hand, the color filter having no light-transmitting protective film (Comparative Example 1) has a reflectance of 6 in the wavelength region of 400 to 700 nm in the region where the colored layer is not formed.
The reflectance was as low as 0 to 70%, and the reflectance was insufficient for use in a reflective liquid crystal display device. In addition, irregular reflection was observed, and as a result of observation with an optical microscope, there was a residue of the photosensitive coloring material used in forming the coloring layer of another color between the aluminum reflecting layer and the coloring layer. It was confirmed that.

[0032]

As described in detail above, according to the present invention, a color filter is provided with a colored layer composed of a plurality of colored patterns on a reflective layer provided on a substrate via a light-transmitting protective film. Since the light-transmitting protective film located between the reflective layer and the colored layer prevents the reflective layer from being eroded by the developer during the formation of the colored layer, the reflective color filter having a high reflectance can be obtained. The light-transmitting protective film can reduce the adhesion of the reflective layer to the photosensitive coloring material, effectively prevent the photosensitive coloring material from remaining in the manufacturing stage, and provide a reflective color filter with extremely low diffuse reflection. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing one embodiment of a color filter of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing another embodiment of the color filter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Color filter 2 ... Substrate 3 ... Reflection layer 4 ... Light transmitting protective film 5 ... Coloring layer 6 ... Planarization layer

Claims (5)

[Claims] 1. A color filter comprising: a substrate; a reflective layer provided on the substrate; and a colored layer formed of a plurality of colored patterns on the reflective layer via a light-transmitting protective film. 2. The color filter according to claim 1, wherein the light-transmitting protective film is a thin film made of an inorganic oxide. 3. The color filter according to claim 1, wherein the light-transmitting protective film is a thin film made of an organic resin. 4. The reflection layer is a layer made of a metal material, and the light-transmitting protective film is a thin film made of a metal oxide generated by treating a surface of the reflection layer. 2. The color filter according to 1. 5. The color filter according to claim 1, further comprising a flattening layer covering the coloring layer.