JPH06214106A - Production of color filter by printing - Google Patents

Abstract

PURPOSE:To obtain a color filter having high density and high accuracy by a gravure direct method by forming a base coating layer having adhesion property and cushion property on the one surface of base material prior to printing of filter elements. CONSTITUTION:Prior to printing filter elements 31-33 for red, green and blue colors on a transparent base material 10 which is the substrate of the color filter, a base coating layer having adhesion property and cushion property is formed on the one surface of the base material 10. Then a color filter element 31 of the first color is formed by a gravure direct printing method on the base material 10 coated with the base coating layer 20. Then, after printing the filter element 31, the second and third color filter elements 32, 33 are formed by the gravure direct method same as the first color. During printing the second and third colors, an enough amt. of ink is transferred from recesses of a master plate by adhesion and cushion effect of the base coating layer. Moreover, the obtd. pattern has high accuracy. After printing, the base coating layer 20 is completely hardened by heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing a color filter having a filter element of red, green, blue or the like on one surface of a transparent substrate by printing by a direct gravure method.

[0002]

[Prior Art and Problems Thereof] A printing method is known as one of color filter manufacturing methods. This method has superior mass productivity and is advantageous in cost as compared with other techniques such as electrodeposition and photolithography (for example, NIKKEI NEW MATERIALS 199).
February 25, 1st edition, p. 48-56 "See" Low-cost filters that hold the key to the spread of color LCDs "). Among such printing methods, the gravure method has a large amount of ink deposition compared to other methods such as planographic printing and letterpress printing, and printing on a color filter substrate such as a plastic film or glass is easy. . Even if this gravure method is adopted, if the gravure offset method is adopted, in which the ink in the recesses (cells) of the plate is once transferred to the rubber blanket and the ink on the blanket is transferred to the base material, the cost and pattern There is a difficulty in terms of accuracy. That is, since the gravure offset printing machine is expensive, the cost advantage is halved, and the pattern accuracy and the ink film thickness are inevitably reduced by transferring the ink twice. In order to eliminate such difficulties, it is preferable to adopt a gravure direct method in which the ink in the recesses of the plate is directly transferred to the substrate side.

However, when the color filter is manufactured by the gravure direct method, it becomes difficult to print the patterns of the second and third colors. It is considered that this is because the ink thickness of the already printed filter element (for example, the one of the first color) makes it difficult to apply the printing pressure in the next printing. In particular, in the case of a color filter, since each filter element is solid and the filter element groups of the respective colors are arranged so as not to overlap with each other, the printed filter element may not be printed when the next filter element is printed. It is unavoidable that it will become an obstacle in giving impression pressure. In order to avoid such printing pressure problems, the ink film thickness must be kept small. However, in that case, the print density becomes low, and a sufficient color density as a filter cannot be obtained.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned examination results, and an object of the present invention is to provide a manufacturing technique capable of obtaining a high-density and high-precision color filter by the gravure direct method. .

[0005]

[Means and Actions therefor] In the present invention, it is premised that the gravure direct method is used. Before printing a group of filter elements such as red, green and blue on one surface of the substrate, first, one surface of the substrate is first printed. An undercoat layer is formed on. The undercoat layer is required to have sufficient tackiness to improve the transferability of the ink and cushioning properties to cover the printing pressure of the second and subsequent colors. Such an undercoat layer, due to its tackiness, greatly improves the transfer rate of ink from the recesses of the plate (for example, 3 times the transfer rate compared to the case without the undercoat layer), and improves the color density of each filter element. Not only does it increase the sharpness of the edges of the pattern. In addition, the undercoat layer enables multicolor printing by a direct method due to its cushioning property, and also enables multicolor printing of each filter element together with the improvement of transferability of ink due to the adhesiveness.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 are sectional views showing an embodiment of the present invention during the process. First, as shown in FIG.
A transparent base material 10 which itself serves as a substrate for a color filter.
To prepare. As the substrate 10, a plastic film, a glass plate or the like can be used, but a plastic film is preferable because it can be wound up. When a plastic film is used, it should be heat resistant enough to withstand the heat treatment at the time of manufacturing the color filter, and be excellent in optical isotropy and transparency. For example, a film of triacetate, polycarbonate, polymethylmethacrylate, polyethylene terephthalate, polyethylene naphthalate, or the like can be used.

Prior to printing the filter elements 31, 32, and 33 of three colors of red, green, and blue on one surface of the base material 10,
The undercoat layer 20 is formed on one surface of the base material 10. As a material for the undercoat layer 20, a water-soluble acrylic resin (trade name:
An aqueous solution was used in which Almatex WA911, manufactured by Mitsui Toatsu Kagaku Co., Ltd.) was used as a main agent, and methoxylated melamine (trade name: Cymel 350, manufactured by Mitsui Cyanamid) was added as a curing agent. The ratio of main agent to curing agent is 4: 1
And This material is spin coated on the substrate 10
Applied to one surface, for example, heat treatment at 70 ° C. for 5 minutes,
Alternatively, by leaving it at room temperature for about 10 hours, an undercoat layer 20 in a slightly tacky state was obtained. The dried undercoat layer 20 has a film thickness of about 4 μm, and
Since the cross-linking of the resin has hardly started, it is flexible and has cushioning properties.

Substrate 10 having such an undercoat layer 20 formed thereon
The color filter element 31 of the first color is printed on the top by the gravure direct method. The ink for forming each filter element 31, 32, 33 including the first color is a solvent type ink material, that is, a resin as a binder,
The ink material is composed of a solvent for dissolving it, a pigment as a colorant, and a dispersant for dispersing the pigment. This ink material is slightly more viscous than normal printing inks in order to obtain higher dimensional accuracy. The viscosity of a normal printing ink for gravure is, for example, 12 to 3 with Zancup # 3.
While it is about 20 seconds, that of the ink material used here is about 30 to 80 seconds.

After the printing of the first color filter element 31 is completed, the second color filter element 32 and the third color filter element 33 are gravure similarly to the first color as shown in FIG. 2 and FIG. Direct printing is performed sequentially. During printing of the second and third colors, a sufficient amount of ink is transferred from the recesses of the plate due to the adhesion and cushioning action of the undercoat layer 20, and the pattern accuracy is high. The ink film thickness of each of the transferred filter elements 31, 32 and 33 is, for example, 2 to 3 μm, and the value thereof sufficiently exceeds the film thickness of 1.5 μm required for color density, and the edge of the pattern. Had sufficient accuracy without sagging. After printing each color, the undercoat layer 20 is completely thermoset by using an oven or the like. In addition, each filter element 31, 3 is provided on the base material 10.
2, 33 (in some cases, each filter element 31, 32,
A light shielding layer is also formed in the boundary region of 33. ) Is covered with a transparent protective film.

In the example shown in the figure, the base material 10 itself is used as the substrate of the color filter, but each filter element 31, 32, 33 printed on the base material 10 may be transferred to another base material. It is also possible to manufacture a color filter. In that case, it is preferable to use a vinylon film obtained by dissolving a polyvinyl alcohol resin in water to form a film as a substrate on which each filter element is printed. This is because the vinylon film with a high degree of saponification (saponification degree of 98 to 99 mol%) does not dissolve in water at room temperature but swells, so its characteristics are utilized. This is because the transfer process can be easily performed. Moreover, since the vinylon film is soft, the undercoat layer 2
Combined with the cushioning property of 0, direct printing can be performed more effectively.

Further, the ink used for printing itself has a considerably higher viscosity than the ordinary gravure ink, but the ink in the recesses of the plate is dried to further reduce the motility, and then the substrate 10 side It can also be transferred.

[0012]

According to the present invention, each filter element 3
Prior to printing 1, 32 and 33, the undercoat layer 20 having adhesiveness and cushioning property is formed on one surface of the substrate 10, so that each filter element 31, 3
2, 33 can be printed with high density and high precision by the gravure direct method, and when manufacturing a color filter, the merit of cost reduction by the printing method can be greatly enjoyed.

[Brief description of drawings]

FIG. 1 is a diagram in the process of an embodiment of the present invention,
It is a figure which shows the state which formed the 1st color.

FIG. 2 is a diagram in the middle of steps of one embodiment of the present invention,
It is a figure which shows the state which formed the 2nd color.

FIG. 3 is a drawing in the process of one embodiment of the present invention,
It is a figure which shows the state which formed the 3rd color.

[Explanation of symbols]

 10 Base Material 20 Undercoat Layer 31, 32, 33 Filter Element

Front page continuation (72) Inventor Kazuo Otake 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Kyodo Printing Co., Ltd. (72) Inventor Katsuaki Terada 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Kyodo Printing Co., Ltd. (72) Inventor Akira Oizumi 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Kyodo Printing Co., Ltd. (72) Inventor Shunsuke Nishikawa 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Kyodo Printing Co., Ltd. (72) Inventor Masazumi Takizawa 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Within Kyodo Printing Co., Ltd. (72) Inventor Takuji Oikawa 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Within Kyodo Printing Co., Ltd.

Claims (3)

[Claims] 1. When printing the ink in the recess of the plate for forming the filter element on one surface of the substrate, an undercoat layer having adhesiveness and cushioning property is provided on one surface of the substrate, and The method of printing by a color filter, wherein the ink of 1) is directly transferred to the substrate side. 2. The method of printing a color filter according to claim 1, wherein the undercoat layer is mainly composed of a water-soluble acrylic resin material. 3. The ink in the concave portion of the plate is dried before being transferred to the substrate side.
The manufacturing method by printing the color filter of.