JPH07234311A - Color filter - Google Patents

Abstract

PURPOSE:To provide a color filter which is produced by a printing method and has good surface flatness. CONSTITUTION:The printing plate of the color filter for a liquid crystal display material produced by subjecting the surface of a transparent substrate which is imparted with light shielding film patterns by using ink of three primary colors or is not imparted with these patterns is subjected to printing of three colors is a waterless flat plate for direct printing. The color filter is obtd. without substantially including a curing stage of the ink between the printing stages of the first color and the second color and between the second color and the third color.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter manufactured by a printing method and having good surface flatness.

[0002]

2. Description of the Related Art For a color filter for a liquid crystal display material, various manufacturing methods such as a dyeing method, a pigment dispersion method, a printing method and an electrodeposition method have been proposed and implemented. Among the various manufacturing methods described above, it is established that the method that can manufacture the color filter at the lowest cost is the printing method in view of the number of manufacturing steps in principle. However, there are still unsolved problems in quality and manufacturing cost.

That is, the major problems in terms of quality are dimensional accuracy and surface flatness. In terms of dimensional accuracy, the pigment dispersion method directly exposes the thin film of the photocurable resin in which the pigment is dispersed by pattern exposure, whereas the printing method is a method of transferring the ink pattern attached to the plate surface formed by pattern exposure Therefore, it is theoretically difficult to achieve the dimensional accuracy equivalent to that of the pigment method by the printing method.

However, in an actual color filter, a black matrix is provided except for some low-priced products, and pixels are generally separated by an opaque portion having a width of at least about 20 μm. Although the dimensional accuracy of the printing method does not reach that of the pigment method, it is possible to suppress the variation in the dimensional accuracy within 20 μm, so that the inferior dimensional accuracy does not actually appear.

On the other hand, inferior surface flatness is in a practically unacceptable range, and therefore many flattening treatment methods have been proposed. Typical flattening methods include a method of pressing with a roller or a flat flat plate, a method of grinding / polishing the color filter surface, and a method of applying a flattening resin layer on the color filter. Proposed.

[0006]

However, the cost problem of the printing method color filter is a substantial manufacturing process as compared with the printing of paper because of the peculiar situation of printing the curable ink on the glass, which is peculiar to the color filter. It comes from the large number.

Almost all of the proposed printing methods employ a method in which an ink image is once transferred from the printing plate surface to the elastic body surface and then retransferred to the glass surface. The reason is that the metal plate that is desirable in terms of dimensional stability is a hard substance and it is difficult to press-bond it to glass, and the dimensional accuracy of printed matter cannot be obtained with a soft rubbery relief plate or screen printing plate. is there. That is, most of the proposed methods are methods of transferring an ink image onto a glass plate through a blanket using a plate-shaped metal intaglio plate or a waterless planographic plate.

In these cases, it is known that the cross section of the transferred one-color ink image is generally a chamfered shape and does not have a rectangular cross section, which causes a problem that the surface of the printed three-color filter is wavy. is there.

Further, there is a problem that it is necessary to cure the ink for each printing of one color in order to repeat the transfer using the rubber blanket in the printing of three colors.

In the case of printing on paper, since the ink solvent is absorbed into the paper and the ink image becomes non-adhesive, there is no problem even if the next color is printed subsequently, and in general, multicolor printing is performed. Although multi-color printing is carried out at the same time on the machine, in the case of a color filter, the ink solvent does not penetrate into the glass, so the ink image is sticky, and if the next color image is printed as it is There is a phenomenon that the ink image of the previous color adheres to the blanket for printing. Therefore, in the printing of the color filter, it is necessary to cure the ink image every time one color is printed, which deteriorates the productivity of the printing work.

An object of the present invention is to provide a color filter which has good flatness and is manufactured with high productivity.

[0012]

The structure of a color filter according to the present invention which achieves the above-mentioned object is to provide three colors on a transparent substrate with or without a light shielding film pattern using inks of three primary colors. In the color filter for a liquid crystal display material produced by performing printing, the printing plate is a waterless planographic printing plate for direct printing, and the first color and the second color, the second color and the third color of the printing process It is characterized in that it does not substantially include an ink curing step.

Further, in the above color filter, the advantage of the three-color printing is particularly remarkable when a multicolor printing machine having a plurality of plate cylinders is used.

Further, in the above-mentioned constitution, the three-color ink pattern is uncured and is flattened by a roller having an ink repellent surface.

The contents of the present invention will be described below.

The present invention relates to a color filter manufactured by using a waterless flat plate for direct printing as a printing plate and performing three-color printing without curing treatment between printing steps.

The waterless lithographic printing plate for direct printing can be printed on the glass surface without a blanket since a rubber elastic layer is provided between the aluminum support and the plate surface.

Even if the second color is printed while the first color ink remains uncured, the plate surface of the second color in the portion in contact with the image of the uncured ink of the first color is ink repellent silicone. Because of the rubber surface, the surface of the uncured ink plate of the first color is not contaminated. The situation is the same for the third color printing.

According to the method of the present invention, the ink curing treatment step between printing steps is not required, and not only a large cost reduction can be obtained by reducing the number of production steps but also the flatness of the surface of the printed matter is significantly improved. An unexpected quality improvement effect was obtained.

[0020]

EXAMPLES The embodiments of the present invention will be described with reference to examples using a flatbed printing machine in the following examples, but the practice of the present invention is not limited to this range, and a multi-color rotary printing machine can be used. The effect of the present invention is particularly exerted when the color filter is manufactured by using it once.

In carrying out the present invention, it is convenient to press the printed uncured ink images of the three colors with a flattening roll to perform a flattening treatment, and then to carry out a curing treatment.
The planarization method is not limited to this method, and it is possible to further improve the planarity by using other known planarization methods such as adding a planarization layer.

(Embodiment 1) As an example of a printing machine, "Ekter C" is used.
L600 "(manufactured by Koyosha Co., Ltd.) was used, a waterless planographic printing plate (manufactured by Toray Co., Ltd.) for direct printing was attached to the blanket cylinder, and the platen plate served as an ink platen for supplying ink. An ink in which an organic pigment is dispersed in an epoxy / melamine-based resin (see Japanese Patent Application Nos. 5256746 / 5-247734) is used to form a stripe of about 90 μm in each color on a glass substrate.
Printed at 0 micron pitch.

Printing was carried out sequentially in the order of blue, red and green without intermediate flattening treatment step and curing treatment step, and pressure was flattened by a roller utilizing the ink repulsion property of the water-free planographic printing plate. FIG. 1 shows the result of measuring the surface roughness of the obtained color filter after the heat curing treatment using a surface roughness measuring instrument “SE-30H” (manufactured by Kosaka Laboratory).

As a comparative example, a normal pear plate was attached to the plate surface plate, and a commercially available blanket was attached to the blanket cylinder.
The same ink as in the example was used, and a flattening roller treatment and a heat curing treatment were performed for each printing of one color, and printing of three colors was performed. The measurement result of the surface roughness is shown in FIG.

As is clear from the results shown in FIGS. 1 and 2,
It was demonstrated that the color filter of this example is excellent in surface smoothness.

[0026]

As described above together with the embodiments, according to the present invention, it is possible to manufacture a color filter having a high productivity, which is the original purpose of the printing method, and having a good surface flatness by the printing method. Became possible.

[Brief description of drawings]

FIG. 1 is a graph showing measurement results of surface roughness of a color filter according to this example.

FIG. 2 is a graph showing measurement results of surface roughness of a color filter according to a comparative example.

Claims (3)

[Claims] 1. A color filter for a liquid crystal display material, which is produced by performing three-color printing on a transparent substrate with or without a light-shielding film pattern using three primary color inks. Is a water-free flat plate for direct printing, which does not substantially include an ink curing step between the printing steps of the first and second colors and the second and third colors. . 2. The color filter according to claim 1, wherein three colors are printed by using a multicolor printing machine having a plurality of plate cylinders. 3. The color filter according to claim 1, wherein the three color ink patterns are uncured and are flattened by a roller having an ink repellent surface.