JPH08313721A - Production of color filter and liquid crystal panel - Google Patents

Abstract

PURPOSE: To prevent mixing of colors and an irregular colored state and to obtain a color filter of high precision by first injecting a coloring material, drying and then injecting the next coloring material when coloring materials of different color elements are arranged on a substrate by an ink-jet method. CONSTITUTION: A black matrix 2 as a light-shielding part is formed on a substrate, on which a resin layer 3 is formed by applying a resin having ink- accepting property. The substrate is set in an ink-jet plotting device and aligned to the position of an ink head. An ink of the first color is injected into the resin layer 3 on the substrate 1 and dried, and then an ink of the second color is injected. After the ink 5 of the second color is dried, an ink 6 of the third color is injected, and if necessary, the ink is dried or the resin layer 3 is hardened by baking. Drying of the ink may be performed only to such a degree that mixing of colors is prevented after the ink is injected and before the ink of the next color is injected. Drying conditions are decided in the range of 30-200 deg.C surface temp. of the resin layer 3 according to the properties of the ink.

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 mainly used for liquid crystal display and a liquid crystal panel using the same.

[0002]

2. Description of the Related Art A color filter used for a liquid crystal display or a camera is a filter in which coloring materials having different color elements are arranged in a mosaic pattern or a stripe pattern. Most commonly, the color elements are the three primary colors of red (R), green (G), and blue (B). In addition, each pixel is R,
Each of G and B is formed of at least one of each color, and generally has a black matrix light-shielding region of a desired width in order to enhance display contrast.

A color filter is generally manufactured by a photolithography method for each color as represented by a pigment dispersion method and a dyeing method. Regarding the electrodeposition method, which has recently received attention, a transparent electrode is patterned on the substrate to form an electrode pattern for electrodeposition first, and then electrodeposition coating consisting of pigment, resin, electrolyte solution, etc. Immerse in the liquid to electrodeposit the first color. This process of electrodeposition is repeated to form the colored layers of R, G, B, and finally firing. This method also requires a patterning process such as a photolithography method, resulting in high manufacturing cost.

Although the printing method does not require a photolithography process, it is not suitable for forming a fine pitch pattern because of its low resolution.

In the method of manufacturing a color filter using the ink jet method, it is ideal that the number of times of alignment between the filter substrate and the ink jet head is reduced and ink of three colors is simultaneously ejected (drawn) in consideration of throughput and the like. However, when three colors are simultaneously ejected, when they come into contact with inks of other colors, the inks are mixed with each other (mixed colors) and the characteristics as a color filter are impaired. (See FIG. 7) Therefore, there arises a problem that a high-definition color filter cannot be obtained or the yield is lowered. Therefore, it has been considered to provide a layer (or a wall) for preventing color mixture at the boundary of each color, but all of them cause a cost increase.

When it is attempted to form the color filters one by one so as not to mix the colors, the takt time for producing one color filter is about three times as long as that for the simultaneous formation of three colors, and the one for each color is required. If it is to be produced by another device, the time for substrate alignment and the cost of the manufacturing device will be increased.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a color filter which uses an ink jet method and which can reduce the cost as compared with the conventional method.

Specifically, it is an object of the present invention to provide a method for manufacturing a color filter with high throughput by one-time alignment with one apparatus. Further, the present invention provides a method for manufacturing a color filter which has a high yield and is inexpensive, and an economical liquid crystal display device, camera, etc. manufactured by the method.

[0009]

The present invention provides a color filter having a color element on a substrate by an inkjet method in a method of manufacturing a color filter in which a color material having a different color element is arranged on a substrate by an inkjet method. And a step of applying a colorant having another color element adjacent to the applied colorant, and a step of drying the color filter.

Further, the present invention is a liquid crystal panel comprising a color filter obtained by the above method and a substrate facing the color filter, wherein a liquid crystal compound is enclosed between the substrates.

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of a color filter manufacturing process and a color filter configuration according to the present invention.

In FIG. 1A, a black matrix 2 which is a light shielding portion is provided on a substrate 1, and a resin layer 3 is formed by coating a resin (composition) having ink receptivity on the black matrix 2. The resin layer 3 can be formed by a coating method such as spin coating, roll coating, bar coating, spray coating, or dip coating, and is not particularly limited.

The above resin has ink receptivity,
Any material can be used as long as it can be cured by heating or the like. For example, acrylic resin; epoxy resin; silicon resin; cellulose derivative such as hydroxypropyl cellulose, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose or its modified product; Are used alone or as a mixture (composition).

Next, the substrate 1 is set in an ink jet drawing device (not shown), and after alignment of the substrate and the head position, the ink of the first color is placed at a desired position and in a desired amount as shown in FIG. Implant into the resin layer 3 on the substrate shown in FIG.
(B)).

As the ink jet system, a bubble jet type using an electric / heat converter as an energy generating element or a piezo jet type using a piezoelectric element can be used, and a colored area and a pattern can be set arbitrarily. .

Next, after the ink according to the present invention has been dried, as shown in FIG. 1C, the second color ink is sprayed onto the resin layer 3 on the substrate at a desired position and in a desired amount. . Next, after the ink is dried, as shown in FIG. 1D, the third color ink is sprayed onto the resin layer 3 on the substrate at a desired position and in a desired amount. If necessary, the resin layer is cured by drying or baking the ink.

As a means for drying the ink, after the ink is sprayed by an ink jet system, warm air of 20 ° C. or more is blown out (FIG. 2- (a)) and a lamp (FIG. 2-
(B)), a small drying means such as an infrared laser can be used, and the temperature of the heated portion is not particularly limited as long as it becomes room temperature or higher.

The ink may be dried after the ink has been ejected and before the next color ink is ejected to such an extent that color mixing can be prevented. The temperature and time of overheating are the nature of the ink and the penetration of the ink into the ink receiving layer. It is selected in a timely manner in consideration of speed, and does not require heating to dry the ink completely. Preferably, the surface temperature of the resin layer is 30 ° C. or higher, 200
It is desirable to keep the temperature below ℃.

FIG. 3 shows a sectional view of a TFT color liquid crystal panel incorporating the color filter obtained by the method of the present invention.

The color liquid crystal panel is formed by putting together the color filter 9 and the counter substrate 14 and enclosing the liquid crystal compound 12. TFTs (not shown) and transparent pixel electrodes 13 are formed in a matrix inside one substrate of the liquid crystal panel. On the inside of the other substrate, a color filter 9 is installed at a position facing the pixel electrode, and a transparent counter (common) electrode 10 is formed on one surface of the color filter 9. Further, an alignment film 11 is formed in the plane of both substrates, and by rubbing the alignment film 11, liquid crystal molecules can be aligned in a certain direction. A polarizing plate 15 is adhered to the outside of each glass substrate,
The liquid crystal compound is filled in the gap (about 2 to 5 μm) between these glass substrates. Further, as the backlight 16, a combination of a fluorescent lamp and a scattering plate (neither of which is shown) is used, and a liquid crystal compound functions as an optical shutter for changing the transmittance of the backlight to perform display.

In this example, a black matrix is formed on the substrate, but the black matrix is formed on the resin layer after forming an effective resin (composition) or after coloring. Also, there is no particular problem, and the form is not limited to this example.

It is desirable that the ink ejection head used in the ink jet system according to the present invention is multi-headed, and that the head and the heating device are installed at a fixed interval. This is because if the ink lands on the resin layer and then immediately dries, the unevenness after drying will become large. However, it is not limited to this as long as the ink droplet can be made sufficiently small.

FIG. 4 shows a schematic view of an example of a color filter producing apparatus using the ink jet method. The apparatus of FIG. 4 vertically scans a unit in which R, G, and B ink ejection heads and a lamp heater are integrated,
This is a device for forming a color filter by scanning the substrate 1 in the lateral direction. In the apparatus of this example, both the unit having the head and the heating means and the substrate are moved, but either one may be moved.

In the example of the apparatus shown in FIG. 5, the head and the heating means are installed independently of each other, and a color filter is created by moving the substrate step-and-repeat like a stepper or at a constant speed. It is an example of a device that can.

Further, as shown in FIG. 6, if the ink ejection head is made with a multi-nozzle according to the pixel pitch,
The color filter can be created on the substrate only by scanning in one direction, and the throughput can be maximized.

Various methods are conceivable for carrying out the present invention by the ink jet method as described above. In any method, after the ink is ejected, it is dried by heating (heating) before ejecting the ink of the next color. The method of providing the means for effecting the above is within the scope of the present invention.

[0027]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. Example 1 A 7059 glass substrate manufactured by Corning Inc. was washed by a conventional method, and a black matrix was formed thereon. On top of that, as an ink receiving layer (resin layer), 5 g of hydroxypropylcellulose (HPC-H manufactured by Nippon Soda) and a methylolated melamine derivative (Sumitec M-3 manufactured by Sumitomo Kasei)
A resin composition having a water-based ink absorbability of 5 g was spin-coated to a film thickness of 1 μm, and prebaked at 90 ° C. for 10 minutes. Next, an R, G, B matrix pattern was formed on this substrate by using an inkjet drawing apparatus as shown in FIG. Infrared lamp (500
The irradiation time of W) was about 3 seconds. No color mixture was observed by microscopic observation. (See FIG. 8) Therefore, it was found that such a drying time is sufficient. Example 2 As in Example 1, a resin composition was spin-coated on a glass substrate with a black matrix so as to have a film thickness of 1 μm, and prebaked at 90 ° C. for 20 minutes. Then 300
Inkjet drawing device with pixels of μm × 300 μm, approximately 30 ml in a grid of 80 μm × 250 μm for each color
7 drops of the above ink were sprayed to form a color filter for liquid crystal. The surface temperature during drying was 60 ° C. Further, the resin layer was cured by heating at 230 ° C. for 30 minutes.

When the thus-prepared color filter for liquid crystal was observed with an optical microscope, defects such as color mixture, color unevenness, and color loss were not observed.

Further, when the liquid crystal panel shown in FIG. 2 was prepared using this color filter and driven, high-definition color display was possible. Example 3 As an ink receiving layer (resin layer), 5 g of hydroxyethyl cellulose (AH-15 manufactured by Fuji Chemical) and a methylolated melamine derivative (Sumitex M-3 manufactured by Sumitomo Kasei)
A color filter for liquid crystal was prepared in the same manner as in Example 2 except that the resin composition consisting of 5 g was used. When observing this liquid crystal color filter with an optical microscope, defects such as color mixture, color unevenness, and color loss were not observed. Example 4 A liquid crystal color filter was prepared in the same manner as in Example 2 except that a bisphenol A type epoxy resin was used as the ink receiving layer (resin layer). 80 because the ink density was low
Nine drops of ink were sprayed onto the 250 μm opening, but no color mixture was observed. Example 5 Similar to Example 1, 6 drops of ink were sprayed onto a 80 × 90 μm pixel on a glass substrate to form a 15 ″ liquid crystal color filter.

Even if the pattern size was reduced, defects such as color mixture, color unevenness, and color loss were not observed. Furthermore, using this color filter, the liquid crystal panel shown in FIG.
When driven, high-definition color display was possible. Example 6 Using the apparatus shown in FIG. 5, a glass substrate having a size of 450 × 500 mm was used, and a color filter having a size of 15 ″ was used.
When chamfered, defects such as color mixture, color unevenness, and color loss were not observed.

In addition, the apparatus shown in FIG. 5 uses a stage for a stepper, and since the ink jet head and the heating device are fixed, the alignment accuracy of the substrate is improved. Since the drawing accuracy can be suppressed within ± 3 μm, the width of the black matrix can be reduced from 20 μm to 10 μm.
It has been possible to reduce the aperture ratio to m, and it has also become possible to improve the aperture ratio.

When this color filter was applied to a simple matrix ferroelectric liquid crystal display, a high-definition and bright color display could be produced.

[0033]

As described above, according to the present invention, with a simple process, a color filter for liquid crystal with high accuracy without defects such as color mixture, color unevenness, and color loss, and a color that enables high-definition color display. A liquid crystal panel can be provided. Further, since the width of the black matrix can be narrowed, the aperture ratio is increased, the display is brightened, and the capacity of the backlight can be reduced. Therefore, a color liquid crystal panel can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a schematic view illustrating a manufacturing process of a color filter according to the method of the present invention.

FIG. 2 is a schematic diagram illustrating a drying step in the method of the present invention, in which (a) is hot air drying and (b) is drying by an infrared lamp.

FIG. 3 is a schematic cross-sectional view illustrating a liquid crystal panel incorporating the color filter of the invention.

FIG. 4 is a schematic view of an example of a color filter producing apparatus according to the method of the present invention using an inkjet method.

FIG. 5 is a schematic view of another example of a color filter producing apparatus according to the method of the present invention using an inkjet method.

FIG. 6 is a schematic view illustrating a color filter producing apparatus according to the method of the present invention using an inkjet method equipped with multiple nozzles.

FIG. 7 is a copy diagram of a microscope observation showing an example of a color filter in which colors are mixed by a conventional method.

FIG. 8 is a copy diagram of a microscope observation showing an example of a high-definition color filter according to the method of the present invention.

[Explanation of symbols]

 1 Color Filter Substrate (Glass Substrate) 2 Black Matrix 3 Ink Receptive Layer (Resin Layer) 4 to 6 R, G, B Inks 9 Color Filter 10 Common Electrode 11 Alignment Film 12 Liquid Crystal Compound 13 Pixel Electrode 14 Glass Substrate Substrate) 15 Polarizing plate 21 Ink ejection head of ink jet device 22 Drying gas blowing nozzle 23 Drying lamp (infrared lamp)

Claims (4)

[Claims] 1. A method of manufacturing a color filter in which colorants having different color elements are arranged on a substrate by an inkjet method, wherein a step of applying a colorant having a certain color element and a colorant having another color element are used. The method for producing a color filter, further comprising: a step of drying the applied colorant between the step of applying the colorant adjacent to the applied colorant. 2. A liquid crystal panel comprising a color filter obtained by the method according to claim 1 and a substrate facing the color filter, wherein a liquid crystal compound is sealed between both substrates. 3. The method according to claim 1, further comprising a step of providing a resin layer having ink receptivity on the substrate before the step of applying the coloring material.
A method for manufacturing the described color filter. 4. A liquid crystal panel comprising a color filter obtained by the method according to claim 3 and a substrate facing the color filter, wherein a liquid crystal compound is sealed between both substrates.