JPH09325206A - Color filter - Google Patents

Abstract

(57) Abstract: A color filter which can easily obtain an overcoat layer having a smooth surface even when the overcoat layer is formed by a known coating means such as a spin coating method and a roll coating method. . In a color filter in which color pixel patterns of a plurality of colors are sequentially formed on a transparent substrate with a color material,
When forming a color pixel pattern for one color of the color pixel pattern, a frame-shaped dummy pattern surrounding the color pixel pattern region is simultaneously formed with the color material of the color pixel pattern for one color. The color filter to use.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a color filter incorporated in a color liquid crystal display device or the like.

[0002]

2. Description of the Related Art A color liquid crystal display device includes a color filter electrode substrate in which a transparent electrode layer is formed on a color filter in which a color pixel pattern is formed on a transparent substrate, and a TFT.
A switching element such as a (thin film transistor) is made to face an electrode substrate formed on a transparent substrate with a predetermined gap, liquid crystal is sealed between both substrates, and the substrates are bonded together.

If the gap between the two substrates facing each other varies depending on the part, the quality of the color liquid crystal display is significantly deteriorated.

Therefore, the surface of the color filter electrode substrate, more specifically, the surface of the color filter is required to be smooth so as to have no unevenness. In order to meet this demand, one means is to form an overcoat layer made of a transparent resin or the like on the color filter so that the color filter surface has smoothness. In this case, a transparent electrode layer is formed on the overcoat layer to form a color filter electrode substrate.

[0005]

Conventionally, in the color filter 1, as shown in FIG. 10, a photosensitive resin in which a color pigment is dispersed in a predetermined portion on the transparent substrate 2, or titanium oxide, silicon oxide, or the like is used. Is used as a coloring material, for example, R (red), G (green), B
A plurality of color pixel patterns 3 composed of a plurality of colors such as (blue) are formed. The area of the color pixel pattern 3 formed on the color filter 1 is generally located near the center of the substrate, away from the plate edge portion of the transparent substrate 2.

For this reason, as shown in FIG. 10, in order to make the surface of the color filter 1 smooth, the overcoat layer 5 is formed on the color filter 1 simply by a known coating method such as spin coating or roll coating. Even if it is formed, it can be said that the raised portion 8 is generated in the overcoat layer in the color pixel pattern 3 region.

Conventionally, in order to make the electrode substrate and the color filter electrode substrate face each other with a predetermined gap, a spacer such as a fine bead sphere having a predetermined particle diameter is sandwiched outside the color pixel pattern area, and then both substrates are placed. The method of facing them is adopted.

However, when the overcoat layer in the color pixel pattern area is bulged or the surface of the overcoat layer is uneven, a predetermined gap accuracy cannot be obtained even if the two substrates are opposed to each other with a spacer interposed therebetween.

Therefore, an overcoat layer having a smooth surface is required, and conventionally, for example, the method described below has been used. That is, for example, by using a spin coat method or the like, as shown in FIG. 10, once the overcoat layer 5 in which the color pixel pattern 3 region is raised is obtained, the raised portion 8 is ground and polished to smooth the surface. However, the method of scraping and polishing the raised portion 8 is
It is difficult to control the layer thickness of the overcoat layer 5, and the layer thickness of the finally obtained overcoat layer 5 tends to be uneven depending on the site, and the specifications of a color liquid crystal display device that requires a highly accurate gap between substrates. It was difficult to provide a surface smoothness that matches the above. Further, the polishing method is very time-consuming and causes contamination, thus reducing the production efficiency of the color filter.

Further, a method of forming an overcoat layer in two steps by using a photolithography method is also performed. That is, a photosensitive material such as a photosensitive resin is used as a main material of the first-stage overcoat layer, and the first-stage overcoat layer 5a is formed on the color filter 1 by, for example, a spin coating method. Next, as shown in FIG. 9A, for example, the first step overcoat layer 5a is formed through the pattern exposure mask 7 in which the color pixel pattern 3 region is used as a light-shielding portion and the outside of the color pixel pattern 3 region is a light transmitting portion. Pattern exposure is carried out to photo-cure the portion of the overcoat layer outside the color pixel pattern 3 region. Next, the overcoat layer 5a of the first stage is developed to remove the overcoat layer in the unexposed and uncured portion. As a result, as shown in FIG. 9B, the color pixel pattern 3
Outside the region, an overcoat layer 5a having the same height as the color pixel pattern is obtained. Next, as shown in FIG. 9C, the second overcoat layer 5b is applied to the color filter 1
Form on top. As a result, an overcoat layer having a smooth surface is finally obtained.

However, also in the method using the photolithography method described above, since the material used as the overcoat layer is a photosensitive material such as a photosensitive resin, resistance such as heat resistance, chemical resistance, moisture resistance and light resistance is obtained. There is a problem that it is scarce. Therefore, the durability of the color filter formed with the overcoat layer is inferior, which in turn affects the durability of the color liquid crystal display device having the color filter incorporated therein. In addition, many photosensitive materials that will be the overcoat layer have a light absorption region in the visible light region, and when a color filter is installed in a color liquid crystal display device or the like,
The visible light with which the color filter is irradiated is absorbed by the overcoat layer, and the display quality is deteriorated.
Further, even in the method using the photolithography method, it can be said that the forming process is complicated and very time-consuming, and the production efficiency of the color filter is reduced.

The present invention has been made in view of the above circumstances, and even if the overcoat layer is formed by a known coating means such as a spin coating method or a roll coating method, the overcoat having a smooth surface is easily obtained. An object of the present invention is to provide a color filter in which a layer can be obtained and solve the above-mentioned problems.

[0013]

In order to achieve the above object in the present invention, first, in claim 1, a color filter in which a plurality of color pixel patterns of color materials are sequentially formed on a transparent substrate. In forming a color pixel pattern for one color of the color pixel pattern,
A color filter is characterized in that a frame-shaped dummy pattern surrounding a color pixel pattern region is simultaneously formed with the color material of the color pixel pattern for one color.

The color filter according to claim 1, wherein the color pixel pattern for one color is a color pixel pattern formed thickest in the color pixel pattern. Is.

The color filter according to claim 1, wherein the frame-shaped dummy pattern is formed of a color material having a light transmission property with respect to ultraviolet light. According to a fourth aspect of the present invention, in the color filter according to the third aspect, the dummy pattern and the color pixel patterns of the same color are thicker than the color pixel patterns of other colors. It is used as a color filter.

Further, in the fifth aspect of the present invention, the frame-shaped dummy pattern is formed by a set of a plurality of patterns which are separated from each other by a UV-permeable gap. The color filter according to claim 6, wherein the color material forming the color pixel pattern is a multilayer interference film according to claim 6. The color filter is as described.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, description will be given with reference to the drawings schematically showing the embodiments of the present invention.

FIG. 1 is a plan view of the color filter 1 of the present invention, and FIG. 2 is a sectional view taken along line XX 'of FIG. As shown in FIG. 1 and FIG. 2, the color filter 1 of the present invention has a conventional multilayer interference film in which titanium oxide and silicon oxide are alternately formed and laminated on a transparent substrate 2 as a coloring material. Method, for example, R (red),
A color pixel pattern 3 region composed of a plurality of colors such as G (green) and B (blue) is formed.

Here, as a feature of the color filter of the present invention, a frame-shaped dummy pattern 4 is formed around the color pixel pattern 3 region. The gap between the color pixel pattern 3 region and the dummy pattern 4 is appropriately set according to the specifications of the color filter.

The dummy pattern 4 formed on the color filter of the present invention is formed at the same time when the color pixel pattern for one color among the color pixel patterns of a plurality of colors is formed. This will be described with reference to FIG. Note that FIG. 4 uses a known method of forming a color pixel pattern using a multilayer interference film as a coloring material.

First, as shown in FIG. 4 (a), after a heat-resistant positive photosensitive resist layer is formed on a transparent substrate 2 such as glass, a pattern exposure mask 7 having a predetermined pattern is used, Pattern exposure is performed on the photosensitive resist layer.
Since the photosensitive resist layer used is a positive type,
In the pattern exposure mask 7, the portion where the color pixel pattern 3R is formed and the portion where the frame-shaped dummy pattern 4 is formed are used as light transmitting portions. Further, if necessary, a black matrix layer having a predetermined pattern is formed on the transparent substrate 2 in advance by using black resin, metallic chrome or the like. Then, the photosensitive resist layer is developed to leave an unexposed portion of the photosensitive resist layer as shown in FIG. 4 (b).

Next, by a low temperature ion assisted vapor deposition method or the like, a multilayer interference film in which titanium oxide, silicon oxide and the like are alternately formed and laminated is formed on the transparent substrate 2 as shown in FIG. 4 (c). Then, the photosensitive resist layer remaining on the transparent substrate 2 is removed using a solvent. This also removes the multilayer interference film on the photosensitive resist layer, and finally,
As shown in FIG. 4D, a color pixel pattern 3R of one color, for example, R (red) color is formed, and at the same time, a dummy pattern 4 of R (red) color is formed around the color pixel pattern area.
Is formed.

Next, when a plurality of colors are required for the color pixel pattern, the steps of FIGS. 4A to 4D are repeated to obtain the remaining color pixel patterns, and the example of FIGS. The color filter 1 of the present invention is shown. The pattern exposure mask used at that time uses a region other than the region where a predetermined color pixel pattern is formed and the already formed dummy pattern 4 as a light shielding part.

In the conventional color filter, as shown in FIG. 10, the region of the color pixel pattern 3 is located near the center of the transparent substrate 2 away from the plate edge portion.
Therefore, when the overcoat layer is formed on the color filter, the overcoat layer portion of the color pixel pattern area is raised.

However, in the color filter 1 of the present invention, a frame-shaped dummy pattern 4 is provided around the area of the color pixel pattern 3 to cover, for example, the plate end portion of the transparent substrate 2. That is, the color filter 1 of the present invention is a color filter formed with a pattern having the same role as that of the first-stage overcoat layer 5a described in FIG. Therefore, even if the overcoat layer 5 is formed on the color filter 1 of the present invention by a known coating means or film forming means such as a spin coating method or a roll coating method, only the color pixel pattern 3 region is raised. Is eliminated, and a substantially smooth overcoat layer 5 can be formed as shown in FIG.

Since the photolithography method is not used for forming the overcoat layer, the overcoat layer 5
The material does not need to have photosensitivity. For this reason,
As a material for the overcoat layer, it is possible to use a highly transparent material such as an acrylic resin or an epoxy resin and having resistance such as heat resistance, chemical resistance, moisture resistance, and light resistance.

Next, the invention according to claim 2 will be described. As described above, in the color filter 1 of the present invention, when the color pixel pattern 3 for one color is formed,
At the same time, the dummy pattern 4 is formed. Therefore, the thickness of the dummy pattern 4 is the same as the thickness of the color pixel pattern 3 formed at the same time. Here, in order to obtain a predetermined spectral characteristic, the thickness of the color pixel pattern 3 of each color may not be constant, and the thickness of the color pixel pattern of each color may be different.

For example, assume that the color pixel patterns 3 for three colors are formed on the transparent substrate 2. At this time, as shown in FIG. 8, it is assumed that the second color pixel pattern 3G is thicker than the first color pixel pattern 3R and the third color pixel pattern 3B. in this case,
When the dummy pattern 4 is formed at the same time as the color pixel pattern 3R of the first color, the thickness of the dummy pattern 4 is thinner than the thickness of the color pixel pattern 3G of the second color, so the color pixel pattern 3G of the second color is as shown in FIG. That is, it can be said that it protrudes from the dummy pattern 4 surface.

When there is a color pixel pattern protruding from the dummy pattern 4 surface, when the overcoat layer 5 is formed, as shown in FIG. 8, the overcoat layer 5 slightly protrudes from the color pixel pattern portion protruding from the dummy pattern 4 surface.
May protrude. When a highly accurate inter-substrate gap is required due to the specifications of the color liquid crystal display device, even this slight protrusion may cause a problem.

That is, as shown in FIG. 5, the color filter according to claim 2 is a color filter in which the dummy pattern 4 is simultaneously formed when the color pixel pattern having the largest thickness is formed among the color pixel patterns of each color. It is a filter. Incidentally, in the example of FIG. 5, the color pixel pattern 3G has the largest thickness, and the dummy pattern 4 is formed simultaneously with the formation of the color pixel pattern 3G. In the color filter according to claim 2, the dummy pattern 4 described above is used.
The protrusion of the color pixel pattern from the surface is eliminated, so that the smoothing accuracy of the overcoat layer 5 formed on the color filter 1 is improved.

By the way, in the process example shown in FIG. 4, when the color filter 1 according to claim 2 is obtained, the dummy pattern 4 is used as the pattern exposure mask used when forming the color pixel pattern having the largest thickness. The part to be formed is a light transmitting part, and the other pattern exposure masks are parts to form a dummy pattern as a light shielding part.

Next, the invention according to claims 3 to 5 will be described below.

As described in the above section (Prior Art), in the color liquid crystal display device, the color filter electrode substrate and the electrode substrate on which a switching element such as a TFT (thin film transistor) is formed are opposed to each other. Are adhered together, and an ultraviolet curable adhesive may be used during this adhesion.

That is, after applying an ultraviolet-curing adhesive to the outside of the color pixel pattern area, the two substrates are bonded together, and then, for example, ultraviolet light is irradiated from the transparent substrate 2 side of the color filter to remove the adhesive. It cures. Note that, depending on the type of the adhesive to be used, after the irradiation of the ultraviolet light, the bonding site or the like may be heated.

In the conventional color filter, almost no pattern is formed outside the color pixel pattern area, and the irradiated ultraviolet light reaches the ultraviolet curable adhesive. However, as mentioned above,
In the color filter 1 of the present invention, a frame-shaped dummy pattern 4 is formed outside the color pixel pattern area.

Therefore, if the coloring material forming the dummy pattern does not have the property of transmitting the irradiated ultraviolet light, the dummy pattern blocks the ultraviolet light. That is, when the color material forming the dummy pattern shields ultraviolet light, the amount of light required for curing the ultraviolet curable adhesive cannot be obtained, and the above-mentioned bonding of both substrates using the ultraviolet curable adhesive is performed. May not be possible.

According to a third aspect of the present invention, the color material of the color pixel pattern is formed simultaneously with the formation of the color pixel pattern having a light transmission property with respect to the ultraviolet light used for curing the ultraviolet curable adhesive. This problem is solved by using a color filter in which a frame-shaped dummy pattern is formed. That is, for example, when a multilayer interference film is used as a coloring material and color pixel patterns of R (red), G (green), and B (blue) colors are formed, for example, B ( A dummy pattern is formed with a (blue) color material. As a result, the irradiated ultraviolet rays are also transmitted through the dummy pattern portion, so that it is possible to bond the both substrates using an ultraviolet curable adhesive as in the conventional case.

Next, the invention according to claim 4 will be described. As described above, when the color pixel pattern is projected from the surface of the dummy pattern 4, the smoothing accuracy of the overcoat layer 5 formed on the color filter 1 is deteriorated. Therefore, as described above, in claim 2,
When forming the color pixel pattern with the thickest,
At the same time, the color filter was formed with the dummy pattern 4.

However, in the color filter according to the third aspect, the frame-shaped dummy pattern is formed by the color material having the light transmission property with respect to the ultraviolet light. When the dummy pattern is formed with the thickness of the pattern, the color pixel pattern of another color may project from the dummy pattern surface. For example,
Conventional R (red), G (green), B using multilayer interference film
In the color filter formed with the (blue) color pixel pattern, the thickness of the color pixel pattern is B
It can be said that the layers are formed thicker in the order of (blue), R (red), and G (green). Therefore, when a dummy pattern is formed with a conventional thickness using a color material having a light transmission property for ultraviolet light, for example, a color material of B (blue) color, a color material of R (red) and G (green) color is formed. The color pixel pattern is projected from the dummy pattern surface.

In order to prevent this, in the present invention, when the dummy pattern is formed of a coloring material having a light transmission property with respect to ultraviolet light, the thickness of the dummy pattern and the color pixel pattern of the same color are The color filter is characterized in that it is thicker than the color pixel pattern of the color.

For example, as a method of increasing the thickness, when the color material is a multilayer interference film, the number of layers is increased when forming the dummy pattern and the color pixel pattern of the same color.
Alternatively, there is a method of forming a transparent layer such as a SiO ₂ layer on at least one of the upper and lower sides of the dummy pattern and the color pixel pattern of the same color, that is, by putting a so-called getter on.

Next, as a modification of the above-mentioned means for solving the problems that occur when the substrates are bonded using the ultraviolet-curable adhesive, the invention according to claim 5, that is, a frame-shaped dummy pattern, The present invention proposes a color filter which is characterized by being formed by a set of a plurality of patterns which are separated from each other by UV-transmittable gaps.

In the above description, the frame-shaped dummy pattern is formed solid. Therefore, if the coloring material forming the dummy pattern does not have the property of transmitting the irradiated ultraviolet light, the dummy pattern blocks the ultraviolet light. However, when the dummy pattern is formed by a set of a plurality of patterns which are separated from each other by a UV-transmittable gap, for example, a set of a plurality of stripe patterns 9 as shown in FIG. It can be said that it can pass between the stripe patterns 9. Therefore, the ultraviolet light passing between the stripe patterns 9 can cure the ultraviolet curing adhesive as in the conventional case, and the substrates can be bonded together.

In addition to the stripe pattern 9 described above, a mosaic pattern, a dot pattern, or the like may be used as the shape of a plurality of patterns that are separated from each other by a space through which ultraviolet rays can pass. Since the size and interval of each pattern vary depending on the specification of the ultraviolet-curable adhesive to be used, that is, the amount of light necessary for curing, it can be said that it is desirable to appropriately set them.

When a dummy pattern formed by a set of a plurality of patterns described above is used, it is not necessary to consider the light transmission characteristics of the coloring material used for the ultraviolet light. With the color material of the color pixel pattern formed to be the thickest among the color pixel patterns formed to have the same thickness, the dummy pattern can be formed simultaneously with the formation of the color pixel pattern formed to the thickest.

The embodiment of the present invention is not limited to the above description and drawings, and it goes without saying that various modifications can be made based on the spirit of the present invention.

For example, in the above-mentioned drawings, the frame-shaped dummy pattern 4 reaches the plate edge of the transparent substrate 2, but it can be said that the frame width does not necessarily have to reach the plate edge of the substrate, and the gist of the present invention is not limited. Therefore, the frame width with which the overcoat layer having a smooth surface can be obtained may be appropriately set.

Further, in the above description, the frame-shaped dummy pattern 4 surrounding the color pixel pattern 3 area is used. However, depending on the specifications of the color filter, as shown in the plan view of FIG. Instead, the corner portion of the color filter 1 by the above-mentioned method,
For example, the dummy pattern 4 may be provided at each alignment mark 6 part.

That is, the electrode substrate and the color filter constituting the color liquid crystal display device are each provided with a registration mark which serves as a reference when the two substrates are opposed to each other. The color filter 1 of FIG. 6 has a cross-shaped alignment mark 6 formed therein.

Usually, this alignment mark is formed on the corner portion of the substrate, and the color filter 1
The dummy pattern 4 is provided at each alignment mark 6 part. In this case, as shown in FIG. 7, when the overcoat layer 5 is formed on the color filter 1, it can be said that the overcoat layer 5 is recessed in a region other than the color pixel pattern 3 region and the dummy pattern 4. However, the color pixel pattern 3 area part and the dummy pattern 4
The overcoat layer 5 having substantially the same thickness is obtained at the portion. As a result, by positioning the above-mentioned spacer for facing the electrode substrate and the color filter electrode substrate with a predetermined gap at the corner portion of the substrate, it is possible to make both substrates face each other with a predetermined gap. It will be.

As described above, by forming the dummy pattern 4 on the alignment mark 6, the alignment mark 6 is formed.
When it becomes difficult to recognize both the substrates and it is difficult to make the two substrates face each other, as shown in FIG. 6, the alignment mark 6 portion may be exposed, for example, a square-shaped dummy pattern 4a. I can say.

Further, the coloring material forming the color pixel pattern may be a photosensitive resin containing a coloring pigment. However, when the frame-shaped dummy pattern 4 is formed by using a photosensitive resin containing a coloring pigment as a coloring material, when the color filter is irradiated with ultraviolet light, the dummy pattern 4 part is shielded from the ultraviolet light. . For this reason,
When an ultraviolet curable adhesive is used to bond the substrates together, it can be said that the dummy pattern 4 is preferably formed by a set of a plurality of patterns separated from each other by a space through which ultraviolet light can pass.

[0053]

As described above (problems to be solved by the invention), the conventional color filter requires a troublesome and complicated forming process to obtain an overcoat layer having a smooth surface. In addition, the material of the overcoat layer is limited in that it must have photosensitivity, so that it is inferior in resistance, and has a light absorbing region in the visible light region. I didn't get it. However, the color filter obtained by the present invention can easily form an overcoat layer having a smooth surface by a known coating method such as a spin coating method or a roll coating method. Further, since the material of the overcoat layer does not need to have photosensitivity, it is possible to use a highly transparent and durable material such as acrylic resin and epoxy resin.

That is, by using the color filter of the present invention, an overcoat layer having a smooth surface can be easily obtained, so that the gap accuracy when the electrode substrate and the color filter electrode substrate are opposed to each other is improved, and the durability is improved. The durability of a color liquid crystal display device incorporating a color filter having a certain overcoat layer is improved. Furthermore, since the color filter of the present invention can form an overcoat layer having excellent transparency, the display quality of the color liquid crystal display device is improved, and a color liquid crystal display device using a conventional substrate bonding means is provided. In other words, the present invention provides practically excellent effects.

[0055]

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a color filter of the present invention.

FIG. 2 is a sectional view showing an embodiment of the color filter of the present invention.

FIG. 3 is a cross-sectional view showing an example in which an overcoat layer is formed on the color filter of the present invention.

4 (a) to 4 (d) are explanatory views showing a main part of an example of a method for producing a color filter of the present invention in process order.

FIG. 5 is a sectional view showing another embodiment of the color filter of the invention.

FIG. 6 is a plan view showing another embodiment of the color filter of the invention.

FIG. 7 is a cross-sectional view showing another example in which an overcoat layer is formed on the color filter of the present invention.

FIG. 8 is a cross-sectional view showing another example in which an overcoat layer is formed on the color filter of the present invention.

9A to 9C are explanatory views showing an example of forming an overcoat layer on a conventional color filter in the order of steps.

FIG. 10 is an explanatory diagram showing an example of a swell of an overcoat layer formed on a conventional color filter.

FIG. 11 is a plan view showing another embodiment of the color filter of the invention.

[Explanation of symbols]

 1 Color Filter 2 Transparent Substrate 3 Pixel Pattern 4 Dummy Pattern 5 Overcoat Layer 6 Alignment Mark 7 Exposure Mask 8 Raised Area 9 Stripe Pattern

Claims (6)

[Claims] 1. A color filter in which color pixel patterns of a plurality of colors are sequentially formed of a color material on a transparent substrate,
When forming a color pixel pattern for one color of the color pixel pattern, a frame-shaped dummy pattern surrounding the color pixel pattern region is simultaneously formed with the color material of the color pixel pattern for one color. The color filter to use. 2. The color filter according to claim 1, wherein the color pixel pattern for one color is a color pixel pattern formed thickest in the color pixel pattern. 3. The color filter according to claim 1, wherein the frame-shaped dummy pattern is formed of a color material having a light transmission property with respect to ultraviolet light. 4. The color filter according to claim 3, wherein the dummy pattern and the color pixel patterns of the same color are thicker than the color pixel patterns of the other colors. 5. The color filter according to claim 1, wherein the frame-shaped dummy pattern is formed by a set of a plurality of patterns separated from each other by a gap capable of transmitting ultraviolet rays. 6. The color material forming the color pixel pattern comprises a multilayer interference film.
The color filter according to 2, 3, 4 or 5.