JP4433247B2 - Manufacturing method of color filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of color filters used for liquid crystal color displays and the like, and particularly relates to a technique for producing a color filter by applying colored ink on a substrate in a line shape by an ink jet method. .
[0002]
[Prior art]
The color filter for liquid crystal has a structure in which pigments of three colors of red, green, and blue are arranged in a mosaic or stripe pattern on a transparent substrate such as glass, and each boundary is partitioned by a black matrix. At present, the pigment dispersion method is the main method for producing this color filter. In this method, first, a red, green, or blue photoreactive resist ink is applied on the entire surface of a glass substrate on which a black matrix is formed, and then only a portion where the applied colored layer is to be formed by mask exposure. Is cured and an unnecessary part is removed by a development process to form a colored layer of the first color, but the same process is repeated three times to obtain three colors of red, green, and blue. Therefore, since the number of steps is large and the resist ink is almost wasted by development, a low-cost and highly efficient color filter manufacturing method is desired. In view of this, a color filter manufacturing method based on an inkjet method has already been proposed in Japanese Patent Application Laid-Open No. 59-75205 as a low-cost and simple color filter manufacturing method.
[0003]
This inkjet filter manufacturing method uses an inkjet head having a plurality of orifices, and discharges colored ink while moving the inkjet head relative to the substrate to apply the ink to the substrate in a line. FIG. 1 shows a schematic diagram of a three-color simultaneous coating method which is a method for forming a colored layer by using a coating apparatus incorporating this inkjet head.
[0004]
In FIG. 1, G is a substrate to be coated placed on the stage S. By moving a coating apparatus having a plurality of inkjet heads relative to the substrate G, colored ink is formed in a line shape. It is comprised so that it may apply | coat to. That is, the left eight inkjet heads Hr eject red colored ink, and are attached to a frame (not shown) so that a plurality of orifices in each inkjet head Hr are continuous in the width direction of the substrate G. . Similarly, the eight coating heads Hg at the center eject green colored ink and are attached to a frame (not shown) so that a plurality of orifices in each inkjet head Hg are continuous in the width direction of the substrate. . Similarly, the right eight inkjet heads Hb eject blue colored ink, and are attached to a frame (not shown) so that a plurality of orifices in each inkjet head Hb are continuous in the width direction of the substrate. Yes. Therefore, the respective ink jet heads move integrally with the substrate while discharging the colored ink from the plurality of orifices, so that the three colored inks are applied in a single application process.
[0005]
As a method for producing a color filter by the ink jet method, three methods are roughly classified.
[0006]
The first method is proposed in Japanese Patent Laid-Open No. 9-203803. This method is a method of providing a partition wall. In this system, first, as shown in FIG. 2A, a partition wall 12 made of a line-shaped resin black matrix is formed on a substrate 11, and a water repellent treatment or the like is applied to an upper portion 12a of the partition wall 12. Then, as shown in FIG. 2B, colored ink 14 is applied from the inkjet head 13 into the partition wall 12. Since the colored ink 14 is prevented from diffusing by the partition walls 12, a colored layer 15 is formed between the partition walls 12 on the substrate 11 as shown in FIG.
[0007]
The second method is proposed in Japanese Patent Laid-Open No. 8-230314. This method is a method of providing an absorption layer. In this method, first, as shown in FIG. 3A, a linear resin black matrix 22 is formed on a substrate 21, and an ink absorption layer 23 is formed so as to cover it. Next, as shown in FIG. 3B, exposure is performed through a mask 24 to cure the upper portion 23a of the black matrix 22 to eliminate absorption, and as shown in FIG. The colored ink 26 is applied from 25 to the ink absorbing layer 23. Since the colored ink 26 soaks into the ink absorbing layer 23, a colored layer 27 is formed between the black matrices 22 on the substrate 21.
[0008]
Since these first and second methods have advantages and disadvantages, the present inventors have already proposed a method such as JP-A-11-337726 as the third method.
[0009]
This third method is a photocatalytic method. In this method, first, as shown in FIG. 4A, a chromium black matrix 32 is formed on a substrate 31, and a photocatalyst containing layer 33 in which titanium oxide is dispersed in a silicone resin is formed thereon as a photocatalyst. The photocatalyst-containing layer 33 has a function of decomposing the organic group in the exposed portion by the decomposition action of the photocatalyst and reducing the ink repellency of this portion. Next, as shown in FIG. 4B, only the portion 33a where the colored layer is formed is subjected to mask exposure through the mask 34, and then, as shown in FIG. When 36 is applied, the colored ink wets and spreads only on the exposed portion with the unexposed portion as a boundary due to the ink repulsion of the unexposed portion. The colored layer 37 can be formed by drying and curing this. The unexposed portion is formed between the pixels, that is, on the black matrix 32 in order to prevent wetting and spreading of the colored ink to the adjacent pixels. Preferably, a range narrower than the width of the black matrix 32 is defined as the unexposed portion. However, a more uniform colored layer can be formed. As the coloring ink, both water-based and solvent-based inks can be used, and preferable solvents include propylene glycol monoethyl ether acetate as a main component, and butyl carbitol acetate for improving ink resilience. The main ink is used. As the colored ink, any of dyes and pigments can be used.
[0010]
[Problems to be solved by the invention]
By the way, when forming the colored layer of the color filter by the above-described ink jet method, there is a problem of variation in the discharge amount between orifices in the ink jet head. That is, if the discharge amount of the colored ink varies between the orifices, color density unevenness is observed for each line of the colored layer, and the quality as a color filter is deteriorated. In particular, in the case of a piezo-type ink jet, the structure of the portion related to driving of the piezo element is complicated, so it is difficult to make a head with little variation, regardless of the accuracy of other portions. Therefore, in order to suppress such variations, a method of averaging by drawing a plurality of times at the same place using a plurality of ink jet heads is also considered, but adjustment of each head position and control of ejection timing can be performed. In addition to being complicated, there is a problem that it takes too much time and productivity is deteriorated.
[0011]
The present invention has been made in view of such a background, and the object of the present invention is to improve the production efficiency when producing a color filter by applying a colored ink to a substrate with a black matrix by an inkjet method. An object of the present invention is to provide a method of manufacturing a color filter that can reduce unevenness in color density for each line without dropping.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a color filter manufacturing method according to the present invention uses an inkjet head having a large number of orifices, and moves the substrate from the orifices while moving the substrate relative to the inkjet head. In the manufacturing method of the color filter including the step of coloring the specific part of the substrate in a pattern applied on the substrate, the ink flow path is branched from one piezo element and droplets of colored ink are dropped through a predetermined number of orifices In addition, the amount of colored ink dropped on each stripe pattern was averaged by dropping colored ink droplets onto one stripe pattern from each orifice in a plurality of piezoelectric elements. It is characterized by that.
[0013]
In the method for manufacturing a color filter having the above-described configuration, it is desirable to dispose the ink jet head so that a plurality of orifices branched and guided from one piezoelectric element are arranged perpendicularly to the stripe direction to be colored.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 5 is a schematic diagram for explaining an example of an inkjet head used in the production method of the present invention. The principle of the ink jet method is that an electric field is applied to the piezo element 1 to expand and contract in the direction of the arrow, and when the piezo element 1 is extended, the colored ink is pushed out from the ink flow path 2 to form the micropores formed below the ink flow path 2. This is a system in which the colored ink 3 is ejected from the orifice. A normal inkjet head has a piezo element 1 and an ink flow path 2 corresponding to each orifice. The inkjet head shown in FIG. The ink flow path 2 is branched from the piezo element 1 to the four orifices, and an electric field is applied to the piezo element 1 so that the colored ink 3 is dropped simultaneously from the four orifices at the end of the branch flow path. It has become.
[0016]
FIG. 6 shows an arrangement example of orifices of the ink jet head shown in FIG. In the orifice arrangement of FIG. 6, four orifices 4 correspond to each piezo element 1 as described in FIG. 5. The mark of the orifice 4 in FIG. 6 shows only the position where the orifice 4 is arranged, and the shape is meaningless. As shown in FIG. 7, the orifices 4 may be arranged in such a manner that the four orifices 4 of one piezoelectric element 1 are arranged in a direction perpendicular to the stripe pattern 5 of the color filter. In FIG. 6, 5a and 5b of the stripe pattern 5 can be coated with an averaged amount of colored ink by dropping colored ink from four piezo elements.
[0017]
Note that the number of orifices that can be ejected by one piezo element is not limited to four, but in order to make the size of the droplets the same, the ink flow paths need to be symmetrical, and 2, 4 , 8...
[0018]
【The invention's effect】
As described above, the present invention uses an inkjet head having a large number of orifices, and applies colored ink from the orifices onto the substrate while moving the substrate relative to the inkjet head, thereby providing a specific portion of the substrate. In a method for manufacturing a color filter including a step of coloring a pattern into a plurality of piezoelectric elements, the ink flow path is branched from one piezoelectric element and droplets of colored ink are dropped through a predetermined number of orifices. Since each ink droplet is dropped from one orifice onto one stripe pattern, the amount of the colored ink dropped on each stripe pattern is averaged, so a large number of inkjet heads are used. Can easily reduce color density unevenness for each line. .
[Brief description of the drawings]
FIG. 1 is a schematic view of a three-color simultaneous coating method performed using a coating apparatus incorporating an inkjet head.
FIG. 2 is an explanatory diagram showing one method for forming a colored layer on a substrate by discharging colored ink from an inkjet head.
FIG. 3 is an explanatory diagram showing another method for forming a colored layer on a substrate by discharging colored ink from an inkjet head.
FIG. 4 is an explanatory view showing still another method for forming a colored layer on a substrate by discharging colored ink from an inkjet head.
FIG. 5 is a schematic diagram for explaining an example of an ink jet head used in the manufacturing method of the present invention.
FIG. 6 is an explanatory view showing an arrangement example of orifices.
7 is an explanatory diagram of the orifice arrangement of FIG. 6. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piezo element 2 Ink flow path 3 Colored ink 4 Orifice 5 Stripe pattern 11 Substrate 12 Partition 13 Inkjet head 14 Colored ink 15 Colored layer 21 Substrate 22 Black matrix 23 Ink absorption layer 24 Mask 25 Inkjet head 26 Colored ink 27 Colored layer 31 Substrate 32 Black matrix 33 Photocatalyst layer 34 Mask 35 Inkjet head 36 Colored ink 37 Colored layer

Claims (2)

A color including a step of using an inkjet head having a large number of orifices, applying a colored ink from the orifice onto the substrate while moving the substrate relative to the inkjet head, and coloring a specific portion of the substrate in a pattern. In the filter manufacturing method, the ink flow path is branched from one piezo element and droplets of colored ink are dropped through a predetermined number of orifices. A method for producing a color filter, characterized in that the amount of colored ink dropped on each stripe pattern is averaged by dropping droplets of colored ink onto the stripe pattern. 2. The color filter manufacturing method according to claim 1, wherein the inkjet head is arranged so that a plurality of orifices branched and guided from one piezoelectric element are arranged perpendicularly to a stripe direction to be colored. The manufacturing method of the filter.

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