JPH0926506A - Color filter and its production and liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain color filters free from faults, such as color mixing, unequal colors and color drop-outs in pixels, at a low cost by imparting a dyeing ink to an ink absorption layer, drying ink under a posi tive pressure and thermally curing the ink absorption layer. SOLUTION: A compsn. which is degraded in the ink absorptivity of photoirradiated parts by photoirradiation or the photoirradiation and heat treatment is applied on a glass substrate 2 formed with a black matrix 1 and is subjected to prebaking at need, by which a compsn. layer 3 degraded in the ink absorptivity of the photoirradiated parts by the photoirradiation or the photoirradiation and the heat treatment is formed. The exposure of the compsn. layer is then executed via a photomask 4 and the parts low in the ink absorptivity are formed in the ink absorption layer. The layer is thereafter colored with respective colors R, G, B by using an ink jet head 5 and the ink is dried. In such a case, the colored substrate is held under the positive pressure to allow the ink to diffuse completely in the ink absorption layer. The substrate is thereafter heat treated at a high temp. for the purpose of fixing and stabilizing the ink. A protective layer 6 is further formed according to need.

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 for a color liquid crystal display used in a color television, a personal computer and the like, and more particularly to a method for manufacturing a color filter using an inkjet recording technology. The present invention also relates to a color filter manufactured using an inkjet recording technique and a liquid crystal panel including the color filter.

[0002]

2. Description of the Related Art In recent years, with the development of personal computers, especially portable personal computers, the demand for liquid crystal displays, especially color liquid crystal displays, has been increasing. However, cost reduction is required for further popularization, and there is an increasing demand for cost reduction of a color filter, which has a large specific gravity in terms of cost.

Conventionally, various methods have been tried to satisfy the above requirements while satisfying the required characteristics of the color filter, but no method has yet been established which satisfies all the required characteristics. Hereinafter, each method will be described.

The first and most frequently used method is the dyeing method. The dyeing method involves first forming a layer of a water-soluble polymer material, which is a material for dyeing, on a glass substrate, patterning this into a desired shape by a photolithography process, and then immersing the obtained pattern in a dyeing bath. To obtain a colored pattern. By repeating this three times, R, G,
A color filter layer of B is formed.

[0005] The second method is a pigment dispersion method, which has recently been replaced by a dyeing method. In this method, first, a photosensitive resin layer in which a pigment is dispersed is formed on a substrate, and a monochromatic pattern is obtained by patterning the photosensitive resin layer. Further, this step is repeated three times to form R, G, and B color filter layers.

A third method is an electrodeposition method. In this method, first, a transparent electrode is patterned on a substrate, and a pigment,
The first color is electrodeposited by dipping in an electrodeposition coating solution containing a resin, an electrolytic solution or the like. This process is repeated 3 times to form R, G, B color filter layers. It is the one that is fired at the end.

As a fourth method, a pigment is dispersed in a thermosetting resin, and printing is repeated three times so that R, G,
After coating B separately, the colored layer is formed by thermosetting the resin. In any method, a protective layer is generally formed on the colored layer.

[0008]

However, what is common to these methods is that the same process needs to be repeated three times in order to color the three colors of R, G and B, resulting in high cost. That is. Also. There is a problem that the yield decreases as the number of processes increases. Further, in the electrodeposition method, since the pattern shape that can be formed is limited, it is difficult to apply the current technology for TFT. Further, the printing method is not suitable for forming a fine pitch pattern because of poor resolution.

As a method of manufacturing a color filter using an ink jet in order to make up for these drawbacks, Japanese Patent Laid-Open No. 59-59 has been proposed.
-75205, JP-A-63-235901, JP-A-1-
There is a proposal in 217320 etc., but it is still insufficient.

Therefore, an object of the present invention is to solve the problems of these conventional methods and to provide a highly reliable color filter satisfying the required properties such as heat resistance, solvent resistance and resolution at a low cost in a short process. Another object of the present invention is to provide a manufacturing method, a color filter and a liquid crystal panel with high reliability. In particular, when the colorant is arranged by ejecting the ink using the inkjet recording device, the ink does not completely diffuse into the ink absorption layer, and it is possible to prevent an uncolored portion from being generated in the peripheral portion of the pixel. A method for manufacturing a color filter is provided.

[0011]

SUMMARY OF THE INVENTION The present invention is a method for manufacturing a color filter, which comprises a step of ejecting ink by an ink jet method to arrange a colorant in a light-transmitting portion on a substrate, and applying dye ink onto the substrate. A heat-curable ink absorbing layer formed on the ink-absorbent layer, the ink is dried under a positive pressure after the application of the ink, and then the ink absorbing layer is heat-cured; Provided is a color filter manufactured by the method; and a liquid crystal panel in which a liquid crystal compound is enclosed between a substrate on which the color filter is arranged and a counter substrate facing the substrate.

When the colored portion is formed by using the ink jet method for the color filter, the ink diffusivity varies depending on the type of the water-based dye ink used in the ink jet method, and among the three colors, B and G are ink diffusive. The sex is a little bad. Therefore, in the method of the present invention, the pressure of the atmosphere in which the ink is dried is made higher than the atmospheric pressure to promote the diffusion of the ink to the ink absorbing layer so that the ink is spread over the entire pixel, so-called "color loss". To obtain a color filter that does not cause

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 is a process drawing showing one embodiment of the method for manufacturing a color filter of the present invention.

In the color filter of the present invention, a glass substrate is generally used as the substrate 2, but the substrate is not limited to the glass substrate as long as it has necessary properties such as transparency and mechanical strength as a color filter. Absent.

FIG. 1A shows a diagram in which the black matrix 1 is formed on the glass substrate 2.

First, on the substrate 2 on which the black matrix 1 is formed, a composition that reduces the ink absorbency of the light-irradiated portion by light irradiation or light irradiation and heat treatment is applied, and prebaked if necessary. Then, the composition layer 3 in which the ink absorptivity of the light-irradiated portion is lowered by light irradiation or light irradiation and heat treatment is formed (FIG. 1B).

Next, the composition layer is exposed through the photomask 4 (FIG. 1C) to form a portion having low ink absorbability in the ink absorbing layer.

By these steps, color mixing of ink can be completely prevented.

As a method of forming the ink absorbing layer,
A coating method such as spin coating, roll coating, bar coating, or dip coating can be used and is not particularly limited.

Next, each color of R, G and B is colored by using the ink jet head 5 (FIG. 1 (d)), and then the ink is dried. When performing this ink drying operation, the colored substrate is kept under positive pressure to completely diffuse the ink into the ink absorbing layer. After the ink is diffused in the pixels, a heat treatment is performed at a high temperature to fix and stabilize the ink.

As the ink jet head, a so-called bubble jet type using an electrothermal converter as an energy generating element, a piezo jet type using a piezoelectric element, or the like can be used, and a colored area and a colored pattern can be arbitrarily set. Can be set.

Next, a protective layer 6 is formed if necessary (FIG. 1 (e)). As the protective layer 6, a thermosetting type resin material is mainly used, but an inorganic film formed by vapor deposition, sputtering or the like can be used, and it has transparency as a color filter. IT
Any material that can withstand the O formation process, the alignment film formation process, and the like may be used.

FIG. 2 shows a sectional view of an example of a TFT color liquid crystal panel incorporating a color filter according to the present invention. The mode is not limited to this example.

A color liquid crystal panel is generally formed by combining a color filter substrate and a counter substrate and enclosing a liquid crystal compound. TFTs (not shown) and transparent pixel electrodes are formed in a matrix on the inner side of the other substrate of the liquid crystal panel. Also, inside the other board,
A color filter is installed at a position facing the pixel electrode so that RGB color materials are arranged, and a transparent counter electrode (common electrode) is formed on one surface of the color filter. Further, an alignment film is formed in the plane of both substrates, and rubbing the alignment film allows liquid crystal molecules to be aligned in a certain direction. A polarizing plate is adhered to the outside of each glass substrate, and the liquid crystal compound is filled in the gap (about 2 to 5 μm) between these glass substrates. As a backlight, a combination of a fluorescent lamp (not shown) and a scattering plate (not shown) is generally used, and a liquid crystal compound is displayed by functioning as an optical shutter for changing the transmittance of the backlight. I do.

[0026]

The present invention will be described below in detail with reference to examples.

Example 1 (1) 10 parts by weight of a terpolymer of N-methylolacrylamide, methyl methacrylate and hydroxyethyl methacrylate (monomer composition ratio = 20: 30: 50) and (2) triphenylsulfonium Composition comprising 0.2 parts by weight of trifluoromethyl sulfonate (TPS-105 manufactured by Midori Kagaku Co., Ltd.), which has water-based ink absorbability and whose ink absorbency in the light-irradiated portion is lowered by light irradiation or by combined use of light irradiation / heat treatment. Prepared above, spin-coated on a glass substrate on which a black matrix is formed, and subjected to a bake for 10 minutes at 60 ° C. to reduce the ink absorbability of the light-irradiated portion by light irradiation or a combination of light irradiation / heat treatment. An object layer was formed. At this time, the film thickness was 1 μm.

Next, the width of the black matrix (40 μm
m) A portion of the composition layer on the black matrix is D through a photomask having a narrower opening (30 μm).
Pattern exposure was performed with eeep UV light at an energy amount of 100 mJ / cm ² , and the ink absorbency of the portion was reduced. Further, the R, G, and B matrix patterns of the openings were colored with a dye ink using an inkjet printer, and then the ink was dried at 90 ° C. for 5 minutes. This drying was performed in a drying furnace whose inside can be pressurized, and the pressure of the atmosphere was raised to 5 kg / cm ² . Further, for the purpose of fixing ink and the like, heat treatment was performed at 230 ° C. for 1 hour.

Next, a two-component thermosetting resin SS-7625 (manufactured by JSR) was spin-coated as a protective layer to a film thickness of 1 μm, and heat-treated at 230 ° C. for 1 hour to cure the resin. .

When the color filter thus manufactured is observed with an optical microscope, the ink is completely diffused in R, G, and B in each pixel, and the peripheral portion is uniformly colored. I was able to confirm that. Also, mixed colors,
No defects such as color unevenness and color loss were observed.

When a liquid crystal panel was produced using this color filter and driven, a high-definition color display was possible.

(Example 2) Ink drying in a drying oven
A color filter was produced in the same manner as in Example 1 except that the atmosphere pressure was 9.5 kg / cm ² .

Observation of the thus-prepared color filter with an optical microscope revealed that the ink was completely diffused in R, G, and B in each pixel and was uniformly colored up to the peripheral portion. I was able to confirm that. Also, mixed colors,
No defects such as color unevenness and color loss were observed.

Further, when a liquid crystal panel was produced using this color filter and driven, high-definition color display was possible.

Comparative Example 1 A color filter was produced in the same manner as in Example 1 except that the drying after coloring the ink was performed under atmospheric pressure.

When the color filter was observed by an optical microscope, it was confirmed that the inks of B and G were not completely diffused among the pixels.

[0037]

As described above, according to the present invention, a highly reliable color filter free from obstacles such as color mixture, color unevenness, and color loss in pixels can be manufactured at low cost.
A liquid crystal panel that gives a high-definition image can be manufactured using the color filter.

[Brief description of drawings]

FIG. 1 is a method 1 for manufacturing a color filter according to the present invention.
It is process drawing which shows an example.

FIG. 2 is a partial cross-sectional view of a liquid crystal panel incorporating the color filter of FIG.

[Explanation of symbols]

 1 Black Matrix 2 Substrate 3 Composition Layer 4 Photomask 5 Inkjet Head 6 Protective Layer

Claims (3)

[Claims] 1. A method of manufacturing a color filter, which comprises a step of arranging a colorant in a light-transmitting portion on a substrate by ejecting ink by an inkjet method, and applying a dye ink to the substrate is a thermosetting process performed on the substrate. A method for producing a color filter, which comprises applying to the ink absorbing layer, drying the ink under a positive pressure after applying the ink, and then thermally curing the ink absorbing layer. 2. A color filter manufactured by the method according to claim 1. 3. A liquid crystal panel in which a liquid crystal compound is sealed between a substrate on which the color filter according to claim 2 is arranged and a counter substrate facing the substrate.