JPH0618714A - Color filter for display - Google Patents

Abstract

PURPOSE:To obtain the color filter for display which decreases the light transmittance and light reflection in inter-picture element parts without degrading brightness and color purity. CONSTITUTION:The main parts of the color filter are constituted of a glass substrate 1, light scattering parts 2 formed by a surface roughening treatment in the inter-picture element parts of the glass substrate 1, metallic light shielding layers 3 formed on the light scattering parts 2, transparent colored layers 4R, 4G, 4B provided in the picture element parts of the glass substrate 1 and transparent electrodes 6 laminated via a smoothing layer 5. The light transmitted through the inter-picture element parts is shielded by the metallic light shielding layers 2 and the light which enters from the glass substrate 1 side and is reflected by the metallic light shielding layers 3 is scattered by the light scattering part 2 and, therefore, the intensity of the reflected light is lowered. The light scattering parts 2 are not formed in the picture element parts of the glass substrate 1, the degradation in the transmittance of the picture element parts and the degradation in the color purity arising from the development defect of the transparent colored layers 4R, 4G, 4B are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter applied to a display such as a liquid crystal display and, more particularly, to an improvement of a color filter having a metal light-shielding layer at a portion between pixels.

[0002]

2. Description of the Related Art A color filter of this type applied to a display such as a liquid crystal display is provided with a transparent substrate such as glass and a pixel portion on the substrate, the transmitted light of which has a different color (for example, red) for each pixel. , Green, blue light three primary colors) and the main part is composed of a transparent coloring layer
The colored light transmitted through the transparent colored layer is used as display light to display a color image. The transparent colored layer is formed at a pixel portion by, for example, applying a colored photoresist on the transparent substrate and selectively exposing and developing the photoresist.

By the way, in order to prevent color mixture of RGB due to transmitted light from a gap (inter-pixel portion) between pixels,
Japanese Patent Laid-Open No. 62-143 discloses a conventional color filter.
As described in Japanese Patent No. 023, a light shielding layer is formed in the inter-pixel portion.

Although a metal thin film, a photosensitive polymer or the like is applied as a material for the light-shielding layer, it has a low light transmittance and fine processing for selectively forming the light-shielding film only in the inter-pixel portion. Metal thin films, especially chrome thin films, have become the mainstream because they are easy to manufacture.

However, since metal generally has a high reflectance, when the display is observed from the transparent substrate side, the portion of the light shielding layer (metal light shielding layer) made of a metal thin film reflects ambient light to lower the contrast. Moreover, there is a problem that the viewing angle characteristic of the display image is deteriorated because it depends on the viewing angle.

In order to solve such a problem, there has been proposed a color filter in which the entire surface of the transparent substrate is roughened to scatter reflected light to improve the contrast and viewing angle characteristics (Japanese Patent Laid-Open No. 61-61). No. 143791).

[0007]

However, in such a prior art, since the entire surface of the transparent substrate is roughened, the transmittance of the substrate is reduced, and the surface to be roughened is the color of the substrate. There is a problem that the brightness of the entire display is lowered on either the filter side or the observation side.

When the transparent colored layer made of the above-mentioned photoresist is applied on the roughened transparent substrate, the adhesion of the photoresist to the transparent substrate becomes too large due to the roughening treatment, and It has a problem that it causes a poor development such as stain and causes a decrease in color purity.

The present invention has been made by paying attention to such a problem, and its object is to reduce the light transmission and the light reflection in the inter-pixel portion without causing the deterioration of the brightness and the color purity. The purpose is to provide a color filter.

[0010]

That is, the invention according to claim 1 is a transparent substrate, a transparent coloring layer which is provided at a pixel portion on the transparent substrate and colors transmitted light for each pixel, and the transparent substrate. Presuming a color filter for display including a metal light-shielding layer provided in the above inter-pixel portion, a light-scattering portion is formed on a transparent substrate at a portion corresponding to the metal light-shielding layer. Is.

In such technical means, the above-mentioned inter-pixel portion means a gap portion between pixels constituting a display image, and generally means a region other than the pixel portion which is patterned in a grid pattern. Further, the light scattering portion formed on the transparent substrate at a portion corresponding to the metal light-shielding layer reflects the reflected light when the light incident on the inter-pixel portion from the viewer side of the display is reflected by the metal light-shielding layer. It has a function of scattering.

Here, since the light scattering portion is formed only on the portion corresponding to the metal light shielding layer on the transparent substrate and is not formed on the pixel portion, lowering of the transmittance at the pixel portion occurs unlike the above-mentioned prior art. Absent. Therefore, it is possible to prevent the display brightness from decreasing even though the light scattering portion is formed. Further, when the transparent colored layer made of photoresist is applied, the adhesion of the photoresist to the transparent substrate does not increase because the light scattering portion is not formed at the pixel portion of the transparent substrate. Therefore, it is possible to prevent the deterioration of color purity because the above-mentioned development failure such as background stain does not occur.

Regarding such a light scattering portion, for example, a portion corresponding to the metal light shielding layer on the transparent substrate is roughened to have an uneven surface, and the light scattering portion is formed on the transparent substrate. This can be formed by providing a light-scattering layer composed of the particles and the binder.

The inventions according to claims 2 and 3 are based on such technical background.

That is, both the inventions according to claims 2 and 3 are based on the color filter according to claim 1, and in the invention according to claim 2, the portion corresponding to the metal light shielding layer on the transparent substrate is roughened. The invention according to claim 3 is characterized in that a light-scattering portion is formed by forming a light-scattering portion. It is characterized in that the light scattering portion is formed by providing a layer.

In order to selectively roughen the portion of the transparent substrate corresponding to the metal light-shielding layer (ie, the inter-pixel portion) in the invention according to claim 2, a photoresist is provided on the transparent substrate. Is applied, and a photomask is used to selectively expose and develop it to expose the inter-pixel portion of the transparent substrate, and the exposed inter-pixel portion is selectively roughened. In addition, the following wet etching or dry etching method, polishing method, or the like can be applied to this roughening treatment.

As the above-mentioned photoresist, a negative (N) type photoresist in which an unirradiated part is dissolved in a developing solution and an irradiated part is insoluble in a developing solution, and a light-irradiated part is dissolved in a developing solution and an unirradiated part is Positive (P) that becomes insoluble in the developer
Any type of photoresist can be applied, and a photomask corresponding to each type of photoresist may be applied.

Next, when the above-mentioned surface roughening treatment is performed by the wet etching method, the following materials can be applied as the etching liquid. That is, a hydrofluoric acid-based aqueous solution such as ammonium fluoride is used when the transparent substrate is made of glass, and a solvent that dissolves the plastic such as chloroform or acetone when the transparent substrate is made of plastic. Can be applied. When the surface is roughened by the wet etching method, it is desirable that the entire surface of the transparent substrate is covered with a hardened resist film or the like so as not to be corroded.

When the above-mentioned surface roughening treatment is performed by the dry etching method, for example, the reverse sputtering method can be applied.

On the other hand, when the above-mentioned roughening treatment is carried out by a polishing method, for example, 10 to 30% by weight of an abrasive having a particle size of 1 to 2 μm is mixed with water, oil or the like (water is efficient). A method using a polishing liquid can be applied. As the abrasive, cerium oxide, zirconium oxide, red iron oxide, chromium oxide, etc. can be used. Alternatively, a sand blast method in which solid particles are blown together with air may be applied. As such solid particles, gold sand, silica sand, etc. can be used, and a suitable spraying pressure is 4 to 7 kg / cm ² .

Next, in the invention according to claim 3, the light-scattering layer provided on the transparent substrate at a portion corresponding to the metal light-shielding layer is a thin film having a thickness of 1 μm or less, which is composed of particles having a submicron diameter and a binder. When the light incident on the inter-pixel portion from the viewer side of the display is reflected by the metal light-shielding layer, the reflected light is scattered at the interface between the particles and the binder to reduce its intensity. The particle size of such particles is preferably smaller than the film thickness of the light-scattering layer, and is preferably about the same as the wavelength of light so that the light is efficiently scattered, and particularly 0.1 to 0.9 μm. preferable. Examples of the material of the particles include organic substances such as resins, zirconium oxide, titanium oxide, other metal oxides, nitrides, fluorides, and inorganic substances such as metals.

On the other hand, the material of the binder may be any one that is colorless and transparent and can be finely processed, and examples thereof include resins, silicon oxides, other metal oxides, nitrides, fluorides, etc. Those are preferable.

The light-scattering layer may be formed as follows. First, the above particles are dispersed in a liquid in which a binder substance is dissolved. At this time,
Care must be taken not to select a solvent that will also dissolve the particles.

When the binder has photosensitivity, the above dispersion liquid is applied onto the transparent substrate by spin coating or roll coating. Then, by exposing through a mask for the metal light-shielding layer or an opposite type mask and developing, a light-scattering layer is formed only on the substrate portion where the metal light-shielding layer is formed. Type of mask above (positive or negative)
Is appropriately set according to the type of the photosensitive material (positive or negative).

On the other hand, when the binder has no photosensitivity, the binder solution in which the particles are dispersed is uniformly applied on the transparent substrate, cured or baked, and then the resist for patterning is further applied. Is applied, exposed and developed to leave the same pattern as the metal light-shielding layer. After the binder layer is etched using this resist pattern as a mask, the resist is peeled off to obtain a light-scattering layer having a desired pattern. Alternatively, if the etching solution for the light-scattering layer and the metal light-shielding layer can be used together, these two layers may be laminated and the light-scattering layer may be etched simultaneously with the metal light-shielding layer.

In addition, instead of dispersing the particles in the binder, a method may be adopted in which the particles are preliminarily arranged on the entire surface of the transparent substrate or on the portion of the substrate where the metal light-shielding layer is provided, and the binder liquid is applied thereon. Good.

When the binder is composed of a metal oxide, a nitride, a fluoride or the like, the light scattering layer can be formed by a dry process such as vacuum deposition or sputtering. That is, when the light scattering layer is formed by vacuum evaporation, the material forming the fine particles and the binder are put in separate crucibles, and the material forming the fine particles is evaporated so that they form fine islands with a diameter of submicron. At the same time, the binder is vapor-deposited so as to fill the gap between the island-shaped fine particles and the island-shaped fine particles, and then a photoresist is coated on these vapor-deposited films, which are exposed and developed through a photomask by a conventional method. After that, the light-scattering layer may be formed by etching and selectively leaving the vapor deposition film in the inter-pixel region. Even when another dry process such as sputtering is used, the light scattering layer can be formed by a method similar to the case of vacuum vapor deposition.

In any case of forming the light-scattering layer, it is desirable to form the light-scattering layer with high accuracy in the inter-pixel portion. However, even if the light-scattering layer slightly remains in the pixel portion, the binder is It is colorless and transparent, and the diameter of the fine particles is sufficiently small so that the display light is not substantially scattered,
It is possible to display a high-contrast image with excellent brightness and color purity.

Next, in the invention according to any one of claims 1 to 3, the material forming the metal light-shielding layer is not particularly limited as long as it has a low transmittance and can be easily subjected to fine processing such as etching. Ni or the like can be applied, and Cr is particularly preferable for the reasons described above. Further, the film thickness is suitably 200 nm to 1 μm, and after uniformly forming the film, the above-mentioned photolithography process including the formation of the photoresist and the etching process is performed to perform the patterning. The method of forming the metal light-shielding layer is arbitrary as long as a uniform thickness and composition can be obtained, and for example, a vacuum vapor deposition method, a sputtering method or the like can be applied. Here, when the invention according to claim 2 is applied in which the transparent substrate surface is roughened to form the light-scattering portion at a portion corresponding to the metal light-shielding layer, for forming the light-scattering portion and for forming the metal light-shielding layer. Resist type (P: positive type,
If it is desired to have the same (N: negative type), both P and N masks to be applied at the time of exposure may be prepared, otherwise, only one type of mask is required.

Further, in the invention according to claims 1 to 3, examples of the material applicable to the transparent substrate include glass and plastic, and glass is generally applied. The transparent colored layer is formed by applying a photosensitive resin, exposing and developing it, and then dyeing it with a dye (staining method), applying a photosensitive resin containing a transparent coloring agent, and then exposing and developing. It can be formed by a known method such as a method (pigment dispersion method) and a method of forming by printing a printing ink containing a transparent colorant (printing method).

Further, in the color filter according to any one of claims 1 to 3, there is provided a transparent electrode layer which is provided on the transparent colored layer and controls the light transmission of the pixel portion by changing the orientation of the liquid crystal for each pixel. Good. As the transparent electrode layer, a material having a light transmittance of 80% or more and a surface resistance value of 50Ω / □ or less can be used. Specifically, ITO (indium tin oxide) formed by a vacuum deposition method or a sputtering method can be used. )
Thin films are often used. Further, if necessary, a smooth layer or a protective layer made of a transparent resin may be provided between the transparent colored layer and the transparent electrode layer.

The applicable range of the color filters according to claims 1 to 3 is naturally applicable not only to the exemplified liquid crystal display but also to another type of display color filter.

[0033]

According to the inventions of claims 1 to 3, since the light-scattering portion is formed on the transparent substrate at a portion corresponding to the metal light-shielding layer, the metal light-shielding layer is provided for the light transmitted through the inter-pixel portion. It is possible to shield this by the action of, while the light incident on the inter-pixel region from the viewer side of the display is scattered by the action of the light scattering part when this light is reflected by the metal light shielding layer. The strength can be reduced.

Further, since the light scattering portion is formed only on the portion corresponding to the metal light shielding layer on the transparent substrate and is not formed on the image portion, the transmittance at the pixel portion does not decrease unlike the prior art. Therefore, it is possible to prevent the display brightness from decreasing even though the light scattering portion is formed. Furthermore, when the transparent colored layer made of photoresist is applied, the adhesion of the photoresist to the transparent substrate does not increase because the light scattering portion is not formed at the pixel portion of the transparent substrate. Therefore, it is possible to prevent a decrease in color purity because a development defect such as background stain does not occur.

[0035]

Embodiments of the present invention will now be described in detail with reference to the drawings.

Example 1 (1) Comparative Experiment of Reflectance with and without Light Scattering Part 2 inch square glass substrate (Corning # 705)
2μ of positive type photoresist on the entire surface of 9)
It was spin-coated to a thickness of m. After the photoresist was dried, the entire glass substrate was immersed in an aqueous solution of ammonium fluoride for several minutes, and the entire surface on the side not coated with the photoresist was etched to roughen it. Next, after dipping the photoresist by immersing it in a photoresist film stripping solution, a Cr film 6 is formed on the entire surface of the roughened side.
A sputtering film was formed to a thickness of 00 nm.

Light was incident from the glass substrate side of the glass substrate on which the Cr film was formed in this manner under the condition of an incident angle of 5 degrees, and the reflectance thereof was measured. The reflectance is 100% that of Al itself.
% And expressed as a percentage with respect to the reflectance of Al itself.

For comparison, a Cr film was similarly formed on a glass substrate which had not been roughened, and its reflectance was measured in the same manner.

The results are shown in FIG. In the figure, α is the case where the surface roughening treatment is applied, and β is the case where it is not applied.
From these results, it was confirmed that the reflectance was significantly reduced in the case where the surface-roughening treatment was applied, as compared with the case where the surface-roughening treatment was not applied.

(2) Display Experiment of Color Filter The color filter according to this example has a glass substrate 1 and a light formed by a roughening treatment on a portion between pixels of the glass substrate 1 as shown in FIG. Scattering section 2 and this light scattering section 2
The metal light-shielding layer 3 formed above and the transparent colored layer 4 of three colors of R, G, B provided on the pixel portion of the glass substrate 1.
R, 4G, 4B, and these metal light shielding layer 3 and transparent colored layer 4
The transparent electrode 6 is laminated on the smoothing layer 5 to form a main part thereof.

The color filter is manufactured through the following steps. That is, FIG.
As shown in A, positive type photoresists 11 and 12 having a thickness of 2 μm were spin-coated on both surfaces of a 4-inch square glass substrate (# 7059 manufactured by Corning Co., Ltd.) 1 and dried. Next, one of the photoresists 11 was exposed to ultraviolet light through the photomask 13 and developed to expose the inter-pixel portion of the glass substrate 1 (see FIG. 5B).

In this way, the glass substrate 1 on which the inter-pixel portion on one side is exposed is immersed in the above-mentioned ammonium fluoride aqueous solution, and the exposed portion is roughened by etching to form the light scattering portion 2.
After forming the photoresist (see FIG. 5C), photoresist 1 on both sides
1 and 12 were peeled off (see FIG. 5D).

Next, the light-scattering portion 2 is provided on the one surface between the pixels.
A 600 nm-thick Cr film was formed by sputtering on the processed surface of the glass substrate 1 on which the film had been formed, and then a positive type photoresist having a film thickness of 2 μm was spin-coated. After the resist was dried, it was exposed to ultraviolet rays using a photomask of the type opposite to the photomask used when forming the light-scattering portion 2, and developed. Further, this was immersed in an aqueous solution of ceric ammonium nitrate to pattern the Cr film, and the resist was peeled off to form the metal light-shielding layer 3 (see FIG. 5E). On top of this, Red, Green, Bl
The transparent colored layers 4R, 4G, and 4B are formed by using color resists in each of which the ue pigment is dispersed.
A polyimide-based smoothing layer 5 of m was spin-coated and heat-cured, and a transparent electrode 6 made of an ITO film was formed thereon by sputtering to obtain a display color filter (see FIG. 1).

For comparison, as shown in FIG. 3, the glass substrate 1 not subjected to the surface roughening treatment is used, and the metal light shielding layer 3, the transparent colored layers 4R, 4G, 4B and the smoothing layer are similarly used. 5 and transparent electrode 6 were formed to obtain a color filter (Comparative Example 1A).

Similarly, as shown in FIG. 4, using the glass substrate 1 whose one surface is roughened, the metal light shielding layer 3, the transparent colored layers 4R, 4G, 4B, the smoothing layer 5, and the transparent layer are formed. The electrode 6 was formed to obtain a color filter (Comparative Example 1B).

Then, when the display experiment of the color filters according to the examples and the comparative examples was conducted, the following results were obtained. That is, in the color filter according to Comparative Example 1A, since the reflected light from the metal light shielding layer 3 of the Cr film was strong, the contrast was low, and the color reproducibility was largely dependent on the viewing angle.

On the other hand, in the color filter according to Comparative Example 1B, the reflected light from the metal light-shielding layer 3 was weaker than that of the color filter according to Comparative Example 1A, and the viewing angle dependency of color reproducibility was also improved. However, the transparent colored layer 4 on the pixel part
The residual stain was observed, the color purity and brightness were low, and the contrast was low.

On the other hand, in the color filter according to the example, the reflected light from the metal light shielding layer 3 is weaker and the viewing angle dependency of the color reproducibility is improved as compared with the color filter according to the comparative example 1A. In addition, compared with the color filter according to Comparative Example 1B, the display light transmitted through the pixel portion was excellent in color purity and brightness, and it was possible to display an image having extremely high contrast.

Example 2 (1) Comparative Experiment of Reflectance with and without Light Scattering Part 2 inch square glass substrate (# 705 manufactured by Corning Incorporated)
After polishing the entire one surface of 9) with a polishing liquid composed of an aqueous solution containing 20% by weight of zirconium oxide fine particles having a particle diameter of 1 μm, a Cr film of 600 n is formed on the entire roughened surface.
A sputtering film was formed to a thickness of m.

With respect to the glass substrate on which the Cr film is formed in this way, the incident angle is 5 from the glass substrate side as in the first embodiment.
The light was incident under the condition of degrees and the reflectance was measured. As for the reflectance, the reflectance of Al itself is 100% as in Example 1.
The percentage is shown with respect to the reflectance of Al itself.

For comparison, a Cr film was similarly formed on a glass substrate which had not been roughened, and its reflectance was measured in the same manner.

The measurement results showed the same tendency as in Example 1 (see FIG. 7), and it was confirmed that the reflectance was lower than that in Comparative Example.

(2) Display Experiment of Color Filter A color filter similar to that of Example 1 shown in FIG. 1 was obtained through the following steps.

That is, a positive type photoresist having a film thickness of 2 μm was spin-coated on one surface of a 4-inch square glass substrate (# 7059 manufactured by Corning Incorporated) and dried.
Next, this surface was exposed to ultraviolet rays using a photomask of the type opposite to that for the metal light-shielding layer, and developed. Using this as a mask, the exposed portion was polished by the polishing liquid (aqueous solution containing 20% by weight of fine particles of zirconium oxide having a particle diameter of 1 μm) to form a light scattering portion, and then the photoresist was peeled off.

Hereinafter, the color filter according to this example was obtained through the same steps as in Example 1.

Further, for the same comparison as in Example 1, a glass substrate 1 whose one surface is roughened as shown in FIG. 4 is used, and a metal light shielding layer 3, transparent colored layers 4R, 4G, 4B,
A color filter (Comparative Example 2) was manufactured by forming the smoothing layer 5 and the transparent electrode 6, and a color filter according to Comparative Example 1A manufactured in Example 1 (see FIG. 3) was also prepared.

In the color filter of Comparative Example 2, the roughening treatment of the glass substrate 1 is performed by the polishing method applied in Example 2.

When the display experiment of the color filters according to these Examples and Comparative Examples was conducted in the same manner as in Example 1, the following results were obtained. That is, in the color filter according to Comparative Example 2, the reflected light from the metal light-shielding film 3 was weaker than that of the color filter according to Comparative Example 1A, and the viewing angle dependency of the color reproducibility was also improved. Background stain was observed on the part where the transparent colored layer 4 remained, and the color purity and lightness were low, and the contrast was low.

On the other hand, in the color filter according to Example 2, the reflected light from the metal light-shielding film 3 was weaker and the viewing angle dependency of color reproducibility was improved as compared with the color filter according to Comparative Example 1A. In addition, compared with the color filter according to Comparative Example 2, the display light transmitted through the pixel portion was excellent in color purity and brightness, and an image having extremely high contrast could be displayed.

Example 3 (1) Comparative Experiment of Reflectance with and without Light Scattering Part 2 inch square glass substrate (Corning # 705)
9) The whole surface of one side is roughened by sandblasting under air pressure of 5 kg / cm ² using air containing Kongoda, and then a Cr film is sputtered to a thickness of 600 nm on the whole roughened surface. A film was formed.

With respect to the glass substrate on which the Cr film was formed in this manner, the incident angle was 5 from the glass substrate side as in Example 1.
The light was incident under the condition of degrees and the reflectance was measured. As for the reflectance, the reflectance of Al itself is 100% as in Example 1.
The percentage is shown with respect to the reflectance of Al itself.

For comparison, a Cr film was similarly formed on a glass substrate which had not been roughened, and its reflectance was measured in the same manner.

The measurement results showed the same tendency as in Example 1 (see FIG. 7), and it was confirmed that the reflectance was lower than that in Comparative Example.

(2) Color filter display experiment A color filter similar to that of Example 1 shown in FIG. 1 was obtained through the following steps.

That is, a positive type photoresist having a film thickness of 2 μm was spin-coated on one surface of a 4-inch square glass substrate (# 7059 manufactured by Corning Incorporated) and dried.
Next, this surface was exposed to ultraviolet rays using a photomask of the type opposite to that for the metal light-shielding layer, and developed. Using this as a mask, the exposed portion was sandblasted with air containing Kongoda to form a light scattering portion, and then the photoresist was peeled off.

Hereinafter, the color filter according to this example was obtained through the same steps as in Example 1.

Further, for the same comparison as in Example 1, the glass substrate 1 whose one surface is roughened as shown in FIG. 4 is used, and the metal light shielding layer 3 and the transparent colored layers 4R, 4G, 4B,
The color filter (Comparative Example 3) was manufactured by forming the smoothing layer 5 and the transparent electrode 6, and the color filter according to Comparative Example 1A manufactured in Example 1 (see FIG. 3) was also prepared.

In the color filter according to Comparative Example 3, the roughening treatment of the glass substrate 1 is performed by the sandblast method applied in Example 2.

When the display experiment of the color filters according to these Examples and Comparative Examples was conducted in the same manner as in Example 1, the following results were obtained. That is, in the color filter according to Comparative Example 3, the reflected light from the metal light-shielding film 3 was weaker than that of the color filter according to Comparative Example 1A, and the viewing angle dependency of color reproducibility was also improved, but Background stain was observed on the part where the transparent colored layer 4 remained, and the color purity and lightness were low, and the contrast was low.

On the other hand, in the color filter according to Example 3, the light reflected from the metal light-shielding film 3 was weaker than that of the color filter according to Comparative Example 1A, and the viewing angle dependency of color reproducibility was improved. In addition, even when compared with the color filter according to Comparative Example 3, the display light transmitted through the pixel portion was excellent in color purity and brightness, and an image having an extremely high contrast could be displayed.

Example 4 (1) Comparative Experiment of Reflectance with and without Light Scattering Part 2-Hydroxyethyl methacrylate (HEMA) 80
Wt%, methoxymethyl acrylamide (MAAm) 1
An aqueous solution obtained by polymerizing 4% by weight, 3% by weight of dimethylaminopropylmethacrylamide (DMAPMA) and 3% by weight of acrylic acid and adding 10% by weight of the diazo resin to the polymer was used as a photosensitive binder. Zirconium oxide fine particles having an average particle size of 0.5 μm were mixed and dispersed in this photosensitive binder at a weight ratio of binder: fine particles = 6: 5, and the obtained dispersion was used for a glass substrate having a size of 2 inches (Corning Corporation). # 7059) with a film thickness of 1 on the entire surface
It was spin coated at .mu.m and dried. Next, the entire surface is exposed to ultraviolet light under the condition of 100 mJ / cm ² to form a light scattering portion, and then a Cr film of 600 n is formed on the entire surface of the light scattering portion.
A sputtering film was formed to a thickness of m.

With respect to the glass substrate on which the Cr film is formed in this manner, the incident angle is 5 from the glass substrate side as in the first embodiment.
The light was incident under the condition of degrees and the reflectance was measured. As for the reflectance, the reflectance of Al itself is 100% as in Example 1.
The percentage is shown with respect to the reflectance of Al itself.

For comparison, a Cr film was similarly formed on a glass substrate which had not been roughened, and its reflectance was measured in the same manner.

The measurement results showed the same tendency as in Example 1 (see FIG. 7), and it was confirmed that the reflectance was lower than that in Comparative Example.

(2) Display Experiment of Color Filter The color filter according to this example is, as shown in FIG. 2, a glass substrate 1, a light-scattering layer 20 formed between the pixels of the glass substrate 1, and a light-scattering layer 20. The metal light-shielding layer 3 formed on the light-scattering layer 20 and the transparent colored layers 4R, 4G, and 4B of three colors of R, G, and B provided on the pixel portion of the glass substrate 1.
And a smoothing layer 5 on these metal light-shielding layer 3 and transparent colored layer 4.
The main part is composed of the transparent electrode 6 laminated via the.

The color filter is manufactured through the following steps. That is, FIG.
As shown in A, the above dispersion was spin-coated on the entire surface of one side of a 4-inch square glass substrate (# 7059 manufactured by Corning Incorporated) to a thickness of 1 μm.

Next, this surface was exposed to ultraviolet light under the condition of 100 mJ / cm ² using a negative mask of a metal light-shielding layer, and developed with acetic acid to scatter light on the inter-pixel portions of the glass substrate 1. Layer 20 was formed (see Figure 6B).

Then, a Cr film having a film thickness of 600 nm was formed by sputtering on the processed surface of the glass substrate 1 on which the light scattering layer 20 was formed, and then a positive type photoresist having a film thickness of 2 μm was spin-coated. After drying this resist, it was exposed to ultraviolet rays using a photomask having a positive pattern of the metal light-shielding layer (see FIG. 6C) and developed.

Further, this was immersed in an aqueous solution of cerium ammonium nitrate to pattern the Cr film, and the resist was peeled off to form the metal light-shielding layer 3 (see FIG. 6D). Transparent colored layers 4R, 4G, and 4B are formed on this using color resists in which red, green, and blue pigments are dispersed, respectively, and a polyimide-based smoothing layer 5 having a film thickness of 2 μm is spin-coated and heat-treated. Cured,
A transparent electrode 6 made of an ITO film was formed thereon by sputtering to obtain a display color filter (see FIG. 2).

Next, for comparison as in Example 1, a glass substrate having a light-scattering layer formed on the entire surface on one side was used, and a metal light-shielding layer, a transparent coloring layer, a smoothing layer, and a transparent electrode were formed. A color filter (Comparative Example 4) was manufactured by the above method, and a color filter according to Comparative Example 1A manufactured in Example 1 (see FIG. 3) was also prepared.

In the color filter according to Comparative Example 4, the light-scattering layer of the glass substrate 1 contained zirconium oxide fine particles having an average particle diameter of 0.5 μm in the photosensitive binder in a weight ratio of binder: fine particles = 6: 5. It is formed by applying the dispersion liquid obtained by mixing.

Then, when the display experiment of the color filters according to these Examples and Comparative Examples was conducted in the same manner as in Example 1, the following results were obtained. That is, in the color filter according to Comparative Example 4, the light reflected from the metal light-shielding film was weaker than that of the color filter according to Comparative Example 1A, and the viewing angle dependency of color reproducibility was also improved, but the pixel portion A background stain with a transparent colored layer remained was observed, and the color purity and lightness were low, and the contrast was low.

On the other hand, in the color filter according to Example 4, the light reflected from the metal light-shielding film 3 was weaker and the viewing angle dependency of color reproducibility was improved as compared with the color filter according to Comparative Example 1A. In addition, even when compared with the color filter according to Comparative Example 4, the display light transmitted through the pixel portion was excellent in color purity and brightness, and an image having an extremely high contrast could be displayed.

[0084]

According to the inventions of claims 1 to 3, since the light scattering portion is formed in the portion corresponding to the metal light shielding layer on the transparent substrate, the light transmitted through the inter-pixel portion is the metal This can be blocked by the action of the light-shielding layer, while the light incident on the inter-pixel region from the viewer side of the display is scattered by the action of the light-scattering portion when this light is reflected by the metal light-shielding layer. As a result, its strength can be reduced.

Further, since the light scattering portion is formed only on the portion corresponding to the metal light shielding layer on the transparent substrate and not on the image portion, the transmittance in the pixel portion does not decrease unlike the prior art. Despite the formation of the scattering portion, it is possible to prevent the display brightness from decreasing.

Further, when the transparent colored layer made of photoresist is applied, since the light scattering portion is not formed at the pixel portion of the transparent substrate, the adhesion of the photoresist to the transparent substrate does not increase. Therefore, it is possible to prevent a decrease in color purity due to poor development.

Therefore, there is an effect that it is possible to provide a color filter in which the light transmission and the light reflection in the inter-pixel portion are reduced without causing the deterioration of the brightness and the color purity.

[Brief description of drawings]

FIG. 1 is a sectional view of a color filter according to Examples 1 to 3.

FIG. 2 is a sectional view of a color filter according to a fourth embodiment.

FIG. 3 is a cross-sectional view of a color filter according to Comparative Example 1A.

FIG. 4 is a sectional view of a color filter according to comparative examples 1B, 2 and 3.

FIG. 5 is an explanatory view showing the manufacturing process of the color filter according to the first embodiment.

FIG. 6 is an explanatory view showing the manufacturing process of the color filter according to the fourth embodiment.

FIG. 7 is a graph chart comparing the reflectance in the example and the comparative example.

[Explanation of symbols]

 1 Glass Substrate 2 Light Scattering Part 3 Metal Light Shielding Layer 4R Transparent Coloring Layer 4G Transparent Coloring Layer 4B Transparent Coloring Layer 5 Smoothing Layer 6 Transparent Electrode 20 Light Scattering Layer

Claims (3)

[Claims] 1. A transparent substrate, and a transparent colored layer which is provided at a pixel portion on the transparent substrate and colors the transmitted light for each pixel.
A color filter for a display, comprising a metal light-shielding layer provided in an inter-pixel portion on the transparent substrate, characterized in that a light-scattering portion is formed on a portion of the transparent substrate corresponding to the metal light-shielding layer. Color filter for display. 2. The color filter for a display according to claim 1, wherein the portion corresponding to the metal light-shielding layer on the transparent substrate is roughened to form the light scattering portion. 3. The light-scattering portion is formed by providing a light-scattering layer containing submicron-sized particles at a portion corresponding to the metal light-shielding layer on a transparent substrate. Display color filter described.