JPS63235901A - Color filter forming method - Google Patents

Abstract

PURPOSE:To reduce the man-hours of manufacture and to improve the operability by moving an ink jet head while controlling the injection of ink from the head. CONSTITUTION:The ink jet head 2 is movable in a plane parallel to a substrate and while the head 2 is moved, ink color particles from the ink injection opening 2a is brought under injection control to draw a pattern on the substrate with color ink. Thus, the movement of the head 2 and the flight of ink particles are controlled to draw the color pattern in specific color on the substrate. When a pattern is drawn in three primary colors, said process is performed three times by using the different colors, and an ink jet mechanism which has three ink injection openings 2a corresponding to the three primary colors is used for the head to manufacture the color filter by performing the drawing process only once. Further, the trouble of blurring is solved by providing a bank 6 which has a step except in a pattern on the substrate previously by using a dielectric film of silicon oxide, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] In a liquid crystal display device, in particular, by providing a color filter in an active matrix type liquid crystal display panel, full color display becomes possible. In the production of color filters, the present invention applies an inkjet recording method that has been put into practical use in printers, thereby solving the problems encountered when producing conventional color filters.

[Industrial application field]

In a liquid crystal display device, a liquid crystal cell corresponding to each pixel does not have a light emitting function, but operates as a shutter.

Therefore, full color display is possible by adding a color filter and a bank light that illuminates it. The present invention relates to a method of forming a color filter used for this purpose.

[Conventional technology]

Currently, there is no established method for forming color filters, and various methods have been tried. The most commonly used method is staining.

The dyeing method is a method in which a pattern is formed using gelatin or the like on a glass substrate, the area outside the color pattern area to be dyed is masked with a resist, and the gelatin is sequentially dyed with a dye. The color filter is then completed by heating and curing the substrate.

Electrodeposition is another method. This is a method in which a color pattern electrode such as a transparent conductive film is formed on a substrate, and the electrode is electrodeposited by immersing it in an electrolytic solution containing a pigment corresponding to each color.

Furthermore, the vapor deposition method covers the outside of the required area with a patterned resist, and then sputters a heat-resistant organic pigment onto the substrate.
Alternatively, it may be deposited by vapor deposition.

In addition, attempts have also been made to form a color pattern directly on a substrate using a printing method.

[Problem that the invention seeks to solve]

Each method of manufacturing a color filter that can be explained using conventional techniques has its advantages and disadvantages.

In the dyeing method and the vapor deposition method, it is necessary to form a resist mask corresponding to each of the three primary colors, and three patterning steps are required. On the other hand, in the electrodeposition method, patterning is performed only once, and the color can be selected by selecting the electrode during electrodeposition.

Further, in the electrodeposition method and the vapor deposition method, there are many restrictions on the selection of the electrodeposition liquid containing the dye or the source of the vapor deposition material.

The printing method also has many technical problems such as dust adhesion and patterning accuracy.

[Means for solving problems]

In order to solve the above problems, printing technology using inkjet, which has been put into practical use in printers, is utilized. The purpose is to manufacture color filters by moving the head while controlling the flying of ink from the inkjet head.

That is, the inkjet head is equipped with a mechanism that can move parallel to the surface of the substrate forming the filter, and a color pattern of a specific color is drawn on the substrate by controlling the movement of the head and the flying of ink particles.

To draw the three primary colors, the above steps are performed three times, each using different ink. If an inkjet mechanism is used in which the head is equipped with three ink ejection ports corresponding to the three primary colors, it is possible to manufacture a color filter in one drawing process.

In inkjet drawing, it is necessary to prevent ink from smearing for each pixel, but this is achieved by using a dielectric film such as silicon oxide on the front plate, which has a step outside the right-hand page area of the pattern. By providing a bank, it is possible to solve the problem of bleeding.

[Effect]

Since research and development of printer devices using inkjet is progressing, the technology can be used in the present invention by simply changing the printing target from paper to a glass substrate. Since the target is a glass substrate, there is a problem of bleeding, but
This can be prevented by forming a dielectric bank on the substrate.

(Example) FIG. 1 schematically shows an example of an inkjet type color filter manufacturing apparatus used in the present invention.

A glass substrate 1 is held horizontally as shown, and color filters are formed on the lower surface of the substrate. The reason is to prevent blurring and dust during printing.

The inkjet head 2 is mounted on a carrier (not shown) with the ink ejection port 2a facing upward, and the carrier is supported by a screw shaft 3 and is movable in the X-axis and Y-axis (perpendicular to the plane of the paper) directions. .

The screw shaft 3 is connected to a rotary drive mechanism 4 for its movement.

The control unit 5 sends control signals for driving the rotational drive mechanism 4 and controlling the inkjet head 2 on and off.

Inkjet ink droplet control involves continuously ejecting ink droplets and turning them on and off by applying electrical charges to the particles.
There is a charge control method that performs off-control, and an on-demand method that sprays ink particles only when necessary, but there is no particular method to choose from.

- For example, a color filter in which R, G, and B shown in Fig. 2 are regularly arranged in order is 100 x 100 x 1 m -
The case of forming on the glass substrate 1 will be taken up. R,G
, B is 100×100 μm 2 , a dielectric film, for example, a bank 6 of a silicon oxide film surrounding each pixel is formed on the substrate at the front side. In the case of a color pattern as shown in Figure 2, the width of the mesh of the base is 10 μm.
A bank 6 of m is formed.

Ordinary photolithography techniques can be applied to form the dielectric bank. As an example, a silicon oxide film is formed to a thickness of 5000 on the entire surface of the substrate, a resist film is applied, the resist in the pixel area is developed and removed by photolithography, and the silicon oxide film in the exposed area is removed by etching.

Next, the above-mentioned substrate is mounted on the apparatus shown in FIG. 1, and only the pattern R in FIG. 2 is scanned using, for example, ink containing a red organic dye as a coloring material and glycol as a solvent. Next, G and B patterns are formed in the same manner.

Using a substrate with the above dimensions, the ink atomization frequency is 2.4k.
In the case of lIz, the color filter ink application process is 10
The results were completed within minutes.

The direction of scanning may be such that the X-axis is the main scanning direction and the Y-axis is the sub-scanning direction, or vice versa. Furthermore, various color pixel arrangement patterns other than those shown in FIG. 2 are conceivable.

In the above explanation, the inkjet head was explained as having one ink ejection port, but by using a head with each RlG and 133 ink ejection ports, it is also possible to produce color filters of three primary colors in one scan. It becomes possible.

〔Effect of the invention〕

Application of the color filter manufacturing method of the present invention greatly contributes to reducing manufacturing man-hours, improving workability, etc. compared to conventional methods.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus used for manufacturing the color filter of the present invention, and FIG. 2 shows an example of the pattern of the three primary colors of the color filter. In the drawings, 1 is a glass substrate, 2 is an inkjet head, 2a is an ink discharge port, 3 is a screw shaft, 4 is a rotational drive mechanism, 5 is a control unit, and 6 is a dielectric bank.

Claims (4)

[Claims] (1) A method of forming a color filter on a transparent insulating substrate (1) for display, comprising an inkjet head (2) movable in a plane parallel to the substrate, while moving the head. A method for forming a color filter, comprising controlling the ejection of color ink particles from the ink ejection opening (2a) to draw a pattern using the color ink on the substrate. (2) The method for forming a color filter according to claim (1), wherein drawing of the pattern is repeated multiple times by changing the color of ink. (3) The method for forming a color filter according to claim (1), characterized in that a plurality of the ink ejection ports (2a) are provided and patterns of a plurality of colors are simultaneously drawn. (4) The pattern is drawn after the substrate (1) is partitioned by providing a bank (6) with steps outside the pattern area. How to form a color filter.