JPH08234020A - Production of color filter - Google Patents

Abstract

PURPOSE: To enable free color arrangement without allowing the arrangement of respective colored layers to be affected by the shapes of a conductive film by forming a photosensitive film of a positive type on a substrate formed with the conductive film over the entire surface of a display region and repeating exposing, developing and electrodepositing. CONSTITUTION: The photosensitive film 3 of the positive type is first applied on the substrate 1 formed with the conductive film 2 over the entire surface of the display region and is then subjected to exposing and developing, by which the photosensitive film 3 is removed only in the part desired to be formed with the first colored layer on the conductive film 2. The first colored layer 4a is then electrodeposited by energizing the conductive film 2 in an electrodeposition bath. Next, the photosensitive film 3 of the part desired to be formed with the second colored layer on the conductive film 2 is removed by exposing and developing and the second colored layer 4b is electrodeposited. Further, the photosensitive film 3 of the part desired to be formed with the third colored layer on the conductive film 2 is removed by exposing and developing and the third colored layer 4c is electrodeposited and thereafter, the remaining photosensitive film 3 is removed and the colored layers 4a to 4c are cured by heating. While the colored layers 4 are three colors, the repetition of the exposing, developing and electrodepositing suffices if >=4 colors are needed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color filter used for multicoloring a display element such as liquid crystal. Specifically, it relates to a method for producing a color filter by electrodeposition.

The present invention is a method for forming a color filter on the surface of a substrate constituting a display device, in which a positive type photosensitive film is formed on the substrate, and exposure, development and electrodeposition are repeated to obtain a desired film. The present invention relates to formation of an array-shaped color filter for a multicolor display element.

[0003]

2. Description of the Related Art The following three methods are generally well known as main methods for forming a color filter on the surface of a substrate of a display device. (I) A method in which a polymer film of gelatin or the like is provided on the surface of the substrate and the film is dyed. (Ii) A method of printing ink directly on the substrate surface by offset printing or the like. (Iii) A method of electrodepositing a polymer in which a dye is dispersed on a patterned conductive film on a substrate.

The method (i) is the most general and has an advantage that a fine pattern can be formed with high precision, but the process is complicated and the cost is high. Although (ii) is very cheap in terms of cost and can be mass-produced, it is difficult to print ink with high accuracy on glass at present, and thus it is not suitable for producing a filter having a fine shape. The method by means of electrodeposition (iii) is described in detail in, for example, Japanese Patent Application Laid-Open No. 59-114572. Processing is also possible.

FIG. 2 shows a color filter for a typical matrix liquid crystal display device manufactured by a conventional electrodeposition method. 2A is a plan view thereof, and FIG. 2B is FIG.
It is sectional drawing which followed the BB 'line of (a). Next, the manufacturing method will be briefly described. A transparent conductive film 2 for driving a liquid crystal is formed on the substrate 1 and patterned in a line shape. Of the transparent conductive films 2, only those for which a first colored layer (for example, red) is desired to be formed are selected, connected to a power source, and energized in an electrodeposition bath to form a first colored layer 4a. . Hereinafter, the color filter of FIG. 2 is manufactured by repeating the same method to sequentially form the second colored layer 4b (for example, green) and the third colored layer 4c (for example, blue).

[0006]

However, the conventional method of manufacturing a color filter by electrodeposition has a problem that the arrangement shape of the colored layers is limited depending on the type of the display element or the number of steps is increased. Was there.

For example, consider the case of a color filter for a simple matrix type multicolor liquid crystal display element. In order to drive the liquid crystal by the simple matrix method, it is necessary to arrange the transparent conductive film 2 for driving in a line. Therefore, if an attempt is made to produce a color filter by electrodeposition using the conductive film 2, only a so-called stripe array color filter in which each colored layer is arranged in a line can be produced (see FIG. 2 (a) above). (See (b)). That is, since the arrangement of the colored layers is limited by the shape of the conductive film 2, there is a drawback that even if an attempt is made to make a color filter such as a mosaic-like arrangement that is advantageous for color mixing, it cannot be made.

Next, a color filter for a so-called active matrix type liquid crystal display device in which a TFT (thin film transistor) is formed on one substrate will be described. In this type of liquid crystal display element, the potential of the substrate facing the TFT needs to be kept constant at all times, so a transparent conductive film may be formed over the entire display area of the substrate, and patterning of the conductive film is generally unnecessary. Is. However, when a color filter is formed on this counter substrate by electrodeposition, first, the conductive film is patterned, each colored layer is electrodeposited, and then the conductive films are electrically connected again or a new color is formed. A step of forming a conductive film on the filter is required. That is, there is a drawback in that the number of whole steps is significantly increased.

[0009]

In order to solve the problems of arrangement limitation and complicated process, the present invention forms a positive type photosensitive film on a substrate on which a conductive film is formed at least over the entire display area. The method of producing a color filter by repeating exposure, development, and electrodeposition was adopted.

[0010]

The present invention uses the positive photosensitive film for exposure,
The position for electrodeposition is determined by developing. for that reason,
It is possible to manufacture a color filter having a free color arrangement without the arrangement of each colored layer being influenced by the shape of the conductive film. Further, in the color filter for active matrix, it is possible to eliminate the step of patterning the conductive film.

Specifically, the positive photosensitive film may be exposed and developed for the number of times of electrodeposition to make holes to expose the conductive film so as to be electrodeposited. For normal full-color display, the types of colored layers are red (R), green (G), and blue (B).
The primary color is selected. At this time, if the colored layers formed by electrodeposition are formed in contact with each other, the actual display pixels have a gap, so that the colored layers can be seen between the display pixels, resulting in poor display quality. In order to avoid this, it is preferable to form a gap without adjoining the colored layers.

However, if there is no layer in the gap, the surface of the substrate becomes uneven due to the thickness of the color filter, which adversely affects the characteristics of the display device such as liquid crystal. To solve this, it is practical to provide an achromatic transparent layer or a black layer in the gap. Regarding the formation of the light-shielding film, see JP-A-59-1
This is disclosed in Japanese Patent Publication No. 59131 (published on September 8, 1984), and the fourth color is used as a light shielding film in the present invention. From the time of the original application, four or more colors are clearly specified in Example 1.

[0013]

EXAMPLES The effects of the present invention will be specifically described below based on examples. (Example 1) FIGS. 1A to 1F are views showing a method for manufacturing a color filter of the present invention. Hereinafter, FIG. 1 (a)
Up to (f) will be described in detail in order. The positive photosensitive film 3 is applied to the substrate 1 on which the conductive film 2 is formed on the entire surface of the display area, exposed and developed to form a first film on the conductive film 2.
The photosensitive film 3 is removed only in the portion where the colored layer is desired to be formed (see FIG. 1A).

By energizing the conductive film 2 in the electrodeposition bath, the first colored layer 4a is electrodeposited (see FIG. 1 (b)).
The portion of the conductive film 2 where the second colored layer is to be formed is removed by exposing and developing the photosensitive film 3 (see FIG. 1C).
The second colored layer 4b is electrodeposited (see FIG. 1 (d)). A portion of the photosensitive film 3 on which the third colored layer is to be formed on the conductive film 2.
Are removed by exposure and development (see FIG. 1E). Third
After electrodepositing the colored layer 4c of No. 3, the remaining photosensitive coating 3 is removed, and the colored layers 4a to 4c are cured by heating (FIG. 1 (f)).
reference).

Usually, in the display element, the colored layer 4 has three colors, but when four or more colors are required, the above exposure and development and electrodeposition may be repeated. By the method described above, a color filter having a colored layer having a desired arrangement shape can be manufactured on a substrate on which the conductive film 2 is formed. When an active matrix type liquid crystal display device was produced by combining this color filter with a substrate provided with a TFT, good color display could be realized.

(Example 2) Colored layer 4 in Example 1
A color filter having a cross-sectional view shown in FIG. 1 (e) in which a gap was provided between a, 4b and 4c was produced. In the subsequent steps, a colored layer is formed in the same manner as in Example 1, and the achromatic layer 5 similar to that in FIG. 1F is formed by electrodeposition in the sectional view after formation of black after removing the photosensitive film. A TFT type active matrix type liquid crystal display device was manufactured using this color filter. In addition to the effect of Example 1, a good color display was obtained because the colored layers were achromatic and there was no step between the colored layers. Was realized.

(Example 3) The achromatic layer 5 formed by electrodeposition after removing the photosensitive film in Example 2 was made transparent and formed by electrodeposition, and then a color filter was prepared in the same manner as in Example 2. The same effect as in Example 2 was obtained. The cross-sectional view after formation is similar to that of FIG.

(Embodiment 4) An example in which the present invention is applied to a simple matrix type liquid crystal display device is shown in FIGS. 3 (a) and 3 (b). FIG. 3A is a plan view of a color filter manufactured by the method of the present invention, and FIG. 4B is A- of FIG. 3A.
It is sectional drawing along the A'line. Since it is a simple matrix type, the conductive films 2 are arranged in a line.

Development, exposure and electrodeposition were repeated on the conductive film 2 by the same procedure as described in Example 1 to form colored layers 4a, 4b and 4c in a mosaic pattern.
The mosaic color filter can be formed on the line-shaped conductive film, which was impossible with the conventional method.

When a simple matrix type liquid crystal display device was manufactured using the color filter of FIG. 3 and compared with the case of the conventional color filter shown in FIG. 2, the appearance of various mixed colors became clearer and the display was improved. The characteristics have improved. In addition,
In this embodiment, an example in which the respective colored layers are arranged in a mosaic pattern has been described, but it goes without saying that other arrangements such as triangles can be freely manufactured by the same method.

Although the present invention utilizes a positive type photosensitive coating, a negative type can be used in principle. Further, the present invention is not limited to a color filter for a liquid crystal display element, and is a manufacturing method which is always effective when a colored layer is formed on the surface of a conductor by electrodeposition.

(Example 5) Coloring layer 4 in Example 4
A colored layer was formed in the same manner as in Example 4 except that a gap was provided between a, 4b, and 4c, and a black achromatic layer 5 was formed by electrodeposition in the gap after removing the photosensitive film. A color filter having the drawing was prepared. A TFT type active matrix type liquid crystal display device was manufactured using this color filter. In addition to the effect of Example 1, a good color display was obtained because the colored layers were achromatic and there was no step between the colored layers. Was realized. The cross-sectional view after formation is the same as FIG. 1F except that the conductive film is linear.

(Example 6) The achromatic layer 5 formed by electrodeposition after removing the photosensitive film in Example 5 was made transparent and formed by electrodeposition, and a color filter was prepared in the same manner as in Example 5 below. The same effect as in Example 5 was obtained. The cross-sectional view after formation is the same as FIG. 1F except that the conductive film is linear.

[0024]

As described above, according to the method of the present invention, a color filter having a desired color arrangement can be manufactured by a simple electrodeposition method without depending on the pattern shape of the conductive film.

[Brief description of drawings]

1A to 1F are manufacturing process diagrams of a color filter according to the present invention.

2A is a plan view of a conventional color filter by electrodeposition, and FIG. 2B is a sectional view taken along line BB ′ of FIG.

3A is a plan view of a color filter manufactured according to the present invention, and FIG. 3B is a sectional view taken along line AA ′ of FIG.

4A is a plan view of a color filter manufactured according to the present invention, and FIG. 4B is a cross-sectional view taken along line CC ′ of FIG. 4A after pre-coloring formation of 4a, 4b, and 4c. Is.

[Explanation of symbols]

 1 Substrate 2 Conductive Film 3 Positive Photosensitive Film 4a, 4b, 4c Colored Layer 5 Achromatic Layer

Claims (3)

[Claims] 1. A method of manufacturing a color filter, comprising the steps of: a) forming a conductive film on at least the entire display region of the substrate or in a desired shape. b) A step of forming a positive photosensitive film on the conductive film. c) A step of forming a first exposed portion on the conductive film by exposing and developing the photosensitive film into a desired shape. d) A step of forming a first colored layer on the first exposed portion by electrodeposition by energizing the conductive film. e) A step of forming the second exposed portion in the conductive film by exposing and developing the photosensitive film again so as to form a predetermined gap with the first colored layer. f) A step of forming a second colored layer by electrodeposition on the second exposed portion by energizing the conductive film. A method of manufacturing a color filter comprising the above steps and the following repeated steps e) and f). 2. The method for producing a color filter according to claim 1, wherein the number of types of colored layers formed by the electrodeposition is four or more. 3. A method of manufacturing a color filter, comprising the steps of: a) forming a conductive film on at least the entire display region of the substrate. b) A step of forming a positive photosensitive film on the conductive film. c) A step of forming a first exposed portion on the conductive film by exposing and developing the photosensitive film into a desired shape. d) A step of forming a first colored layer on the first exposed portion by electrodeposition by energizing the conductive film. e) By exposing and developing the photosensitive film again,
A second layer is formed on the conductive film with a predetermined gap from the first colored layer.
Forming an exposed portion of the. f) A step of forming a second colored layer by electrodeposition on the second exposed portion by energizing the conductive film. g) A step of repeating steps e) and f) a predetermined number of times. h) A step of peeling off the photosensitive film. i) A step of forming an achromatic layer on the conductive film on which the colored layer is not formed by electrodeposition by energizing the conductive film. The method of manufacturing a color filter according to claim 2, further comprising: