JPH08106086A - Production of color filter and multicolor display device - Google Patents

Abstract

PURPOSE: To provide an industrially advantageous method, which is capable of inexpensively producing a high precision color filter excellent in evenness, that is film thickness uniformity, at high yield, particularly useful for producing the color filter in the case of increasing the size of a substrate and the available area of screen of the substrate, and a producing method of a high quality large screen color LCD. CONSTITUTION: In the producing method of the color filter by electrodeposition method for selectively forming a colored coating film on a conductive layer of a substrate 1 provided with the conductive layer on the surface by using the substrate 1 as an electrode of one side and a plate like conductive body as the counter electrode 2, the plate like conductive body having larger surface ratio to the substrate 1 than 1 is used as the counter electrode 2 and a multicolor display device is produced by using the color filter produced by the method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter and a method for manufacturing a multicolor display device using the color filter. More specifically, the present invention relates to a method of manufacturing a color filter by an electrodeposition method and a method of manufacturing a multicolor display device, for example, a color liquid crystal display device (LCD) using the color filter.

[0002]

2. Description of the Related Art Conventionally, LCDs using liquid crystals have been used for so-called pocket televisions and the like, but in recent years, their size and screen have been rapidly increased. The image quality is also TN (twis
t nematic) liquid crystal to STN (super-t
Wist nematic liquid crystal and TFT (thin)
In the development of an active driving element represented by a film transistor, a CRT approaching commercialization has been commercialized. It is known that a color filter used for making an LCD multi-colored is manufactured by a method such as a dyeing method, a pigment dispersion method, an electrodeposition method, and a printing method. Among these methods, in particular, the electrodeposition method can form a colored coating film with high precision simply by immersing the substrate having the conductive layer and the counter electrode in the electrodeposition liquid bath and applying a voltage and heat treatment. It is attracting attention because it has the advantages of simple process, high yield, and inexpensive color filter manufacturing.

The conventional typical electrodeposition method will be described in more detail. First, a transparent substrate such as glass having a transparent conductive layer such as ITO (indium tin oxide) on its surface is immersed in an electrodeposition bath. At this time, as the electrodeposition liquid, a color pigment, a polymer material, an organic solvent and the like are mixed and dispersed at a predetermined ratio, and the temperature is maintained at a predetermined temperature. Further, in the electrodeposition liquid tank, opposing electrodes are installed in parallel with each other at a predetermined interval so as to face the substrate on which the colored coating film is formed. As the counter electrode, a conductive plate such as a stainless plate is often used. After the transparent substrate is immersed in the electrodeposition liquid bath, in the case of anion electrodeposition, a voltage of 10 V to 300 V is applied for 1 second to 3 minutes by using the conductive layer side of the substrate as an anode and the counter electrode side as a cathode. A colored layer is selectively formed on the conductive layer of the substrate. After that, the substrate is pulled up from the electrodeposition liquid tank, washed to wash away excess electrodeposition liquid, and then heat-treated at a predetermined temperature. If desired, the desired multicolor color filter can be manufactured by repeating this electrodeposition operation a plurality of times.

[0004]

However, large-screen LCDs and high-definition LCs that are expected to be widely used in the future are expected.
In addition to D, of course, it is now strongly desired to produce higher quality color filters at low cost, and in particular, development of a method for producing color filters with good flatness, that is, film thickness uniformity, at high yield. Is desired. In the current method for producing electrodeposited color filters, the film thickness distribution of the colored coating film is quite good, but inevitably the electrodeposited film thickness at the end of the utilization surface in the substrate tends to be unstable. As a result, the overall film thickness distribution tends to be poor. In the future, if the size of the substrate increases and the ratio of the area used within the substrate increases even for substrates of the same size, the film thickness instability at this edge will be further promoted.
This will greatly affect the quality of the color filter.
An object of the present invention is to solve such a problem, in particular, a uniform film thickness is obtained even at the end of the substrate utilization portion, the overall film thickness distribution is good, and a large screen and high-definition multicolor are provided. It is an object of the present invention to provide a method for inexpensively and industrially producing a high-quality color filter capable of producing a display device.

[0005]

According to the present invention, a substrate having a conductive layer on its surface is used as one electrode, and a plate-shaped conductor is used as a counter electrode to selectively form a colored coating film on the conductive layer of the substrate. In the method for producing an electrodeposited color filter to be formed, a plate-shaped conductor having an area ratio to the substrate of more than 1 is used as a counter electrode, and a color filter produced by the method. Is a method for manufacturing a multicolor display device.

The present invention will be described in detail below. In the present invention, the substrate used as one of the electrodes can be manufactured by a known method. For example, a transparent conductive film such as an ITO film (tin-doped indium oxide film) or a NESA film (antimony-doped tin oxide film) is formed on a transparent substrate such as a glass plate or a plastic plate by a conventional method. can do. If necessary, the transparent conductive film on the transparent substrate can be formed into a plurality of transparent conductive circuits having a desired shape that are insulated from each other by a method such as etching.

The resistivity of such a conductive layer is not particularly limited, but the lower it is, the better, and in order to improve the flatness, it is 30Ω.
/ □ or less, preferably 20Ω / □ or less, more preferably 15Ω / □ or less. Moreover, it is preferable that the resistivity distribution in the substrate is uniform. Further, the flatness of the substrate is preferably as flat as possible in order to form a uniform colored film having a good film thickness distribution. In principle, the size of the substrate is not limited as long as these conditions are satisfied, and a color filter of an arbitrarily large substrate can be produced. Productivity can be improved by enlarging the substrate, which is one of the major advantages of the electrodeposition method.

The ratio (used area ratio) occupied by the conductive layer on the substrate is not particularly limited, but is usually 60% or more.

The material of the plate-shaped conductor used as the counter electrode is not particularly limited as long as it is a conductor that does not react with the electrodeposition liquid, and for example, stainless steel is a typical material. The plate-shaped conductor may be in the form of a plate, but is preferably in the form of a wire mesh in order to further improve flatness, and its shape may be completely different from that of the substrate, but preferably the substrate. Is the same or similar. The area ratio of such a plate-shaped conductor to the substrate is larger than 1, preferably about 1.3 or more, more preferably about 1.5 or more. The upper limit of the area ratio is not particularly limited and can be appropriately determined from the viewpoint of workability and productivity.

The electrodeposition can be performed by a generally known method. The electrodeposition method includes an anion type and a cation type, and either method can be used in the present invention, but the anion type electrodeposition method is preferable because it has little influence on the circuit. The resin material (binder) of the electrodeposition liquid used for electrodeposition includes maleated oil-based, acrylic-based, polyester-based,
Examples thereof include resins that may be photocurable, such as polybutadiene resins and polyolefin resins. These can be used alone or as a mixture. A dye having a desired hue such as a dye or a pigment is added to these binders. The electrodeposition liquid can be generally prepared by dispersing, dissolving and diluting components such as a binder and a dye in a suitable solvent. Water, an organic solvent, etc. are used as a solvent. The electrodeposition liquid tank is not particularly limited as long as it is an insulator made of a material capable of holding the electrodeposition liquid, and for example, a plastic electrodeposition liquid tank such as hard vinyl chloride or acrylic resin is used.

The above electrodeposition liquid is placed in such an electrodeposition liquid tank, and the substrate and the plate-shaped conductor are placed in parallel so as to face each other. At this time, it is preferable that the substrate is installed so that its central portion coincides with the central portion of the plate-shaped conductor.

In the case of performing anion electrodeposition, when a DC voltage is applied with the conductive layer of the substrate as an anode and the plate-shaped conductor as a cathode, a colored coating film is selectively formed on the conductive layer.

The thickness of the colored coating film can be controlled by controlling the electrodeposition conditions. The electrodeposition condition is usually 10 to 300 V and 1
It is about 2 to 3 minutes. It is desirable that the colored coating film be thoroughly washed after forming the coating film to remove unnecessary substances. To increase the strength of the coating film, if necessary, 100 to 280 ° C, 10 to
The heat treatment can be performed for 120 minutes.

In the present invention, if desired, a light-shielding film called a black matrix can be formed in the gap between the colored coating films by a known method. In this way, it is possible to industrially advantageously manufacture a color filter that is excellent in various properties required for a color filter such as flatness and that can manufacture a large-screen, high-definition multicolor display device. it can. Using the color filter manufactured by the method of the present invention, a high quality color L
A multicolor display device such as a CD can be manufactured.

[0015]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

Example 1 Phthalocyanine green SAX (manufactured by Sanyo Dye Co., Ltd.) was dispersed in Svia ED-3000 (anionic polyester resin type electrodeposition coating, manufactured by Shinto Paint Co., Ltd.) to prepare a green electrodeposition liquid.

A 70 μm wide ITO film (15Ω /
□) Circuits are formed in strips at intervals of 30 μm (100 μm pitch), length 342 mm, width 300 m
A glass substrate having a thickness of m and a thickness of 1.1 mm was prepared. As a counter electrode, a stainless mesh electrode having a length of 480 mm and a width of 350 mm, which is about 1.6 times larger than the area of the substrate, was prepared.

The above-mentioned electrodeposition liquid was placed in the electrodeposition liquid tank, and the substrate and the counter electrode were placed parallel to each other with their surfaces facing each other at a predetermined interval. At this time, the substrate was placed so that the upper portion of the counter electrode and one side thereof were aligned. (Figs. 1 and 2)

Using the ITO circuit on the substrate as an anode, 3
Electrodeposition was performed under conditions of 0 ° C., 50 V and 10 seconds to form a colored coating film on the ITO circuit. Then take out the substrate 1
It was dried at 20 ° C. for 10 minutes.

With respect to the substrate on which the colored coating film was formed in this manner, the film thickness at 14 points was measured using a stylus type film thickness meter (Dektak 16000 type), and the throwing coefficient was calculated. Covering coefficient (%) = {(maximum film thickness-minimum film thickness) /
(Average film thickness at 14 points)} × 100 As a result, the throwing coefficient was 15% or less, which was evaluated as “excellent” in the actual size of the substrate.

Example 2 A colored coating film was formed by electrodeposition in the same manner as in Example 1 except that the substrate was placed so that its central portion coincided with the central portion of the stainless steel mesh electrode (FIG. 3). . As a result, the throwing coefficient was smaller than that in Example 1.

Comparative Example Electrodeposition was carried out in the same manner as in Example 1 except that a stainless plate electrode having a length of 342 mm and a width of 300 mm was used as the counter electrode to form a colored coating film. The throwing coefficient was much higher than 15%.

[0023]

According to the method of the present invention, a highly accurate color filter having excellent flatness, that is, film thickness uniformity can be produced at a high yield and at a low cost. It is useful for manufacturing a color filter when the used area ratio as is increased, and uses the color filter manufactured by the method of the present invention to manufacture a multi-color display device such as a large screen and a high-definition color LCD. can do.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the positions of a substrate and a counter electrode in Example 1 of the present invention (corresponding to the upper portion of the substrate).

FIG. 2 is a schematic view from the side of the electrodeposition tank showing the positions of the substrate and the counter electrode in Example 1 of the present invention.

FIG. 3 is a schematic diagram showing positions of a substrate and a counter electrode in Example 2 of the present invention (corresponding to the central portion of the substrate).

[Explanation of symbols]

 1 substrate having a conductive layer on the surface 2 counter electrode 3 electrodeposition liquid 4 electrodeposition power supply

Claims (2)

[Claims] 1. A color filter for electrodeposition method in which a substrate having a conductive layer on its surface is used as one electrode and a plate-shaped conductor is used as a counter electrode to selectively form a colored coating film on the conductive layer of the substrate. In the manufacturing method, as the counter electrode,
A method for producing a color filter, which comprises using a plate-shaped conductor having an area ratio of more than 1 to a substrate. 2. A method for manufacturing a multi-color display device, which comprises using the color filter manufactured by the method according to claim 1.