JP4433245B2 - 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 ink jet method described above, it is usually necessary to apply colored ink to 1000 or more stripe patterns for each of the RGB colors. Therefore, in consideration of productivity, it is desirable to use an inkjet head having a large number of orifices. However, since a piezo element that pushes out colored ink is provided for each ink flow path connected to the orifices, it matches the required resolution. Therefore, there is a problem that it is structurally difficult to arrange a large number of piezoelectric elements. In addition, the formation of the colored layer is different from the graphic application, and there is also a problem of variation in dots where the colored ink is dropped. As a method for correcting the variation in dots, there is a method for correcting the voltage applied to the piezo element. However, this also has a problem that control becomes difficult when the number of dots increases.
[0011]
The present invention has been made in view of such a background, and an object of the present invention is to provide a resolution required for producing a color filter by applying a colored ink to a substrate with a black matrix by an inkjet method. Another object of the present invention is to provide a method of manufacturing a color filter that enables the application of colored ink with the number of orifices matched to the above, and that allows the color ink to be dripped onto a substrate with less variation in size.
[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 method for manufacturing a color filter including the step of coloring a specific portion of the substrate in a pattern, the inkjet head having a structure in which the ink flow path is branched from one piezoelectric element to a plurality of orifices is used. The color ink is dripped simultaneously from a plurality of orifices.
[0013]
In the color filter manufacturing method, the lengths and thicknesses of the plurality of ink flow paths from one piezo element to the plurality of orifices may all be the same.
[0014]
In the color filter manufacturing method having the above-described configuration, a plurality of orifices branched from one piezoelectric element may be arranged in a line in a direction perpendicular to the relative movement direction of the inkjet head. Good.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 5 is a schematic view for explaining an ink jet head used in the method for producing a color filter 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. In this method, the colored ink 3 is ejected from the orifice. An ordinary ink jet head has a piezo element and an ink flow path corresponding to each orifice. The ink jet head shown in FIG. 5 has an ink so that one piezo element 1 reaches two orifices. The flow path 2 is branched, and an electric field is applied to the piezo element 1 so that colored ink is dropped simultaneously from two orifices at the end of the branch flow path.
[0017]
FIG. 6 shows an example of the arrangement of the orifices. The orifice arrangement in FIG. 6 is a case where ink is dropped from two orifices 4 with one piezo element as in the case described in FIG. 5, and the orifices 4 are not arranged linearly on the orifice plate 5. Is illustrated. That is, since the colored ink is simultaneously ejected from the two orifices 4 corresponding to the same piezo element, as shown in FIG. 7, the direction perpendicular to the stripe pattern 6 of the color filter is adjusted with the angle adjusted for pitch adjustment. Are arranged so that two orifices 4 are aligned. By not arranging the orifices 4 linearly in this way, the interval can be increased and the space for arranging the piezoelectric elements can be increased.
[0018]
In this way, when colored ink is ejected from a plurality of orifices using a single piezo element, the ejection from each orifice cannot be controlled independently. Need to be arranged in a line in a direction orthogonal to.
[0019]
Note that the number of orifices that can be ejected by one piezo element is not limited to two, but in order to make the size of the droplets the same, the ink flow paths need to be symmetrical, and 2, 4 , 8...
[0020]
Also, since it is necessary to make the size of the ink droplets ejected from the plurality of orifices the same, the length and thickness of the plurality of ink flow paths from one piezo element to the plurality of orifices are all the same. It is desirable to do.
[0021]
In the above description, the stripe-shaped pixels are described. However, the target substrate in the present invention is not limited to the stripe-shaped substrate, but includes a matrix-shaped substrate. That is, in the case of a matrix-like color filter, even if the pixels are arranged in a matrix, pixels of the same color are arranged in parallel as shown in FIG. Color ink can be applied to the substrate from the orifice 4 by a method and colored in a pattern.
[0022]
【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 color filter, an ink jet head having a structure in which an ink flow path is branched from one piezo element to a plurality of orifices is used, and colored ink is simultaneously supplied from a plurality of orifices. By dripping, the number of piezo elements can be greatly reduced, so it becomes possible to increase the number of orifices according to the required resolution, and the control of the entire piezo element becomes easy, so colored ink Can be accurately dropped on the substrate to color the pixels.
[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 view for explaining an ink jet head used in the production 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.
FIG. 8 is an explanatory diagram for applying colored ink to pixels arranged in a matrix.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piezo element 2 Ink flow path 3 Colored ink 4 Orifice 5 Orifice plate 6 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 (3)

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, an ink jet head having a structure in which an ink flow path is branched so as to reach a plurality of orifices from one piezoelectric element is used, and colored ink is simultaneously dropped from the plurality of orifices. A method for producing a color filter. 2. The method for producing a color filter according to claim 1, wherein a plurality of ink flow paths from one piezoelectric element to a plurality of orifices have the same length and thickness. 3. The color filter manufacturing method according to claim 1, wherein a plurality of orifices branched from one piezoelectric element are arranged in a line in a direction perpendicular to a relative movement direction of the ink jet head. A method for producing a color filter characterized by the above.

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