JPH0545513A - Formation of color filter - Google Patents

Abstract

PURPOSE:To form the color filters of thick films which are free from unequal film thicknesses by repeating thin-film printing, thereby forming the thin films. CONSTITUTION:The color filter material is transferred onto a printing plate 2 mounted on a printing roller 1 and the printing plate 2 is rotated and moved and is brought into tight contact with a glass substrate 3, by which the substrate is printed. Namely, the uniform thin film is formed by printing the color filter film (a) and the color filter material is freshly transferred into the printing plate 2 and the color filter film (b) is formed on the color filter film (a) under the same conditions. Further, the color filter film (c) is similarly printed on the films (a), (b) to form the thick film. The film thicknesses can be controlled by the time when the respective color filter films (a), (b), (c) are printed. Further, the glass substrate 3 is rotated 180 deg. at every printing of the color filter films and the printing direction is changed, by which the unequal printing and unequal thicknesses generated by the repetition of the thin film printing are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a color filter, and more particularly to a method for forming a color filter used in a color image pickup device, a contact image sensor, a color liquid crystal display or the like.

[0002]

2. Description of the Related Art Conventionally, a printing method has been used in consideration of cost and mass productivity as a method for forming a color filter used in a color image pickup device, a contact image sensor, a color liquid crystal display, etc. For example, a flexographic printing method in which a color filter material is transferred to a printing plate provided on a printing roller and then the color filter material is transferred to a glass substrate is used.

In addition, as a method of forming a color filter pattern, there are a method of printing a predetermined pattern shape on the pattern and a method of forming a pattern by a photolithography process after printing. At the same time as forming the color filter by these methods. Alternatively, the pattern is formed in another process.

[0004]

However, since color characteristics are important for color filters, the normal thickness is 1.
Since it is necessary to set the thickness in the range of 3 to 1.8 μm and make the film thickness uniform, the conventional method for forming a color filter by a printing method such as flexographic printing has the following drawbacks.

Due to the low viscosity of the color filter material, the amount transferred to the printing plate or the glass substrate is small, and it is impossible to print with a large film thickness.

When the viscosity of the color filter material is increased to increase the transfer amount, the variation in the film thickness after printing is increased, the color characteristics are not uniform, and the quality of the color filter is deteriorated.

The present invention has been made in order to improve the drawbacks of the prior art as described above, and an object thereof is to provide a method for forming a color filter having a thick film with no film thickness unevenness. ..

[0008]

That is, the present invention is a method for forming a color filter, which is characterized in that a thin film printing is repeated to form a film in the method for forming a color filter by a printing method.

The color filter formed in the present invention is formed into a desired film thickness by repeating thin film printing at least twice, and the film thickness is preferably controlled by the time of repeating thin film printing. Further, it is preferable to form the films so that the printing directions of the repeated thin film printing are different.

[0010]

In the method of forming a color filter of the present invention, thin film printing is repeated to form a film. Therefore, compared with the conventional method of forming a film by a single printing method, the color filter is thicker and has uniform film thickness. Can be formed.

Further, in the method for forming a color filter of the present invention, it is possible to control the formation of a thick film (1.5 to 1.8 μm) by the time for repeating thin film printing, and further, in the printing direction when repeating thin film printing. By changing, it is possible to form a color filter which is particularly thick and has a uniform thickness.

[0012]

EXAMPLES The present invention will be described more concretely with reference to the following examples.

Example 1 FIGS. 1A and 1B are explanatory views showing an example of a method for forming a color filter of the present invention. In the figure, 1 is a printing roller to which a printing plate is attached, 2 is a printing plate on which a color filter material such as a dye is transferred, and 3 is a glass substrate on which a color filter is printed.

The method for forming a color filter of the present invention is
First, the color filter material is transferred to the printing plate 2 attached to the printing roller 1, and the printing plate 2 is rotated and moved to be in close contact with the glass substrate 3 for printing. First, the color filter film (a film) of a is printed (see FIG. 1A). By this thin film printing of the a film, for example, a film thickness of 0.3
A uniform thin film of 0.8 μm can be formed.

Next, the color filter material is newly transferred to the printing plate 2, and the color filter film (b film) of b is printed on the color filter film of a under the same conditions as described above. Further, by the same printing method, the color filter film (c film) of c is printed on the a film and the b film, and the thick film (1.3 to
1.8 μm) can be formed (see FIG. 1B).

At this time, the film thickness can be controlled by the time for printing the a film, the b film, and the c film. For example, when the printing time is 10 to 40 seconds, the film thickness is 1.3 to
When it becomes 1.5 μm and 60 to 120 seconds,
The film thickness is 1.6 to 1.8 μm. The film thickness is R,
Since it depends on the G and B color filter materials,
It is necessary to set the printing frequency and time depending on the material.

Next, FIGS. 3A to 3C are explanatory views showing another example of the method for forming a color filter of the present invention.
FIG. 3 shows a method in which the printing direction is changed to reduce the variation in film thickness. In the figure, 1 is a printing roller, 2
Is a printing plate, 3 is a glass substrate, and 4 is a contact pin of a printing machine.

In FIG. 3 (a), a color filter film (e film) of e is first prepared by the same method as the printing method of FIG.
To print. Next, the glass substrate 3 is rotated 180 ° to reverse the printing direction, and the color filter film of f (f film)
Is printed (see FIG. 3B). Next, the glass substrate 3 is rotated by 90 ° to print a g color filter film (g film) (see FIG. 3C).

In this way, while changing the printing direction, e
By printing the film, f film, g film, thick film (1.3 ~
It was possible to prevent uneven printing and uneven film thickness caused by repeating thin film printing.

FIG. 2 shows that the viscosity of the color filter material is changed from 500 to 600 cp, which is usually used, to 2000 to cp.
It is an explanatory diagram showing an example in which the thick film printing is possible by increasing the transfer amount to 5000 cp, but the variation in the film thickness becomes large.

As shown in the above embodiments, according to the method of the present invention, it is possible to form a color filter having good color characteristics, because it is possible to reduce variation in film thickness with a thick film. Further, the present invention is particularly suitable for a method for forming a color image sensor, a contact image sensor, a color filter used in a color liquid crystal display and the like.

[0022]

As described above, according to the present invention,
In the method of forming a color filter by a printing method, by repeatedly printing a thin film having a uniform film thickness and changing the printing direction, there is an effect that a color filter having a thick film and having no film thickness unevenness can be formed.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a method for forming a color filter of the present invention.

FIG. 2 is an explanatory diagram showing a method of forming a color filter printed by using a color filter material having an increased viscosity.

FIG. 3 is an explanatory view showing another example of the method for forming a color filter of the present invention.

[Explanation of symbols]

 1 substrate 1 printing roller 2 printing plate 3 glass substrate 4 contact pins a to g color filter film

Claims (3)

[Claims] 1. A method of forming a color filter by a printing method, wherein thin film printing is repeated to form a film. 2. The method for forming a color filter according to claim 1, wherein the film thickness is controlled by the time for repeating the thin film printing. 3. The method for forming a color filter according to claim 1, wherein the printing directions of the repeated thin film printing are different.