JP2004191799A - Color filter with transparent conductive film and polishing method of color filter with transparent conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter with a transparent conductive film having a smooth surface and to provide a manufacturing method of the same. <P>SOLUTION: The color filter having no fine ruggedness on the surface thereof is stably manufactured at satisfactory yield without being affected by a film-depositing condition of the transparent conductive film by performing a surface smoothing treatment according to working methods related to the claim in the present invention after the transparent conductive film is formed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color flat panel display device, and more particularly to a method for manufacturing a color filter substrate with a transparent conductive film used in a color flat panel display device.
[0002]
[Prior art]
The color filter used in the color flat panel display device divides each pixel on a transparent substrate and forms a black matrix that shields light, and then red (R), green (G), and blue (B). Colored pixels are formed by regularly arranging pixels made of a material that transmits only each wavelength (hereinafter referred to as RGB layer). This is not only for the purpose of enabling color display in a single color display device, but also in a display device having a color display function, preventing a decrease in contrast due to external light, improving the display color of each color and improving the quality of the color. It has functions such as display. Therefore, as the color flat panel display, the current mainstream transmissive liquid crystal display panel, reflective liquid crystal display panel, plasma display panel, inorganic electroluminescence panel, organic electroluminescence panel, encapsulated electrophoretic display are used. Essential for all types of color flat panel displays, such as electronic paper. Further, in most color filters used in such a color flat panel display, a transparent conductive film having a plurality of patterns formed in a line is often formed as an electrode used for display in most cases.
The colored pixel portion of the color filter is formed by a method such as a dyeing method, a pigment dispersion method, an electrodeposition method, or a printing method. A protective layer made of a synthetic resin composition is provided on the colored pixels. The protective layer fills the steps of the colored pixels to flatten the surface and protects the colored pixels. A transparent conductive film for driving the color flat panel display device is formed on the protective layer. Taking a liquid crystal display device as an example, if a large convex portion is formed on the protective layer, the transparent conductive film on the color filter is short-circuited with the counter substrate, or display unevenness is caused by the difference in thickness of the liquid crystal layer due to the unevenness. It happens. (For example, see Patent Document 1)
[0004]
In addition, glass fibers, beads, etc. may be used to control the gap when the panel is made. In this case, if there is a protruding part, it will be sunk in that part, peeling of the transparent conductive film, Electrical short circuit between the films, partial thinning of the color filter layer, and disconnection of the transparent conductive film occur.
[0005]
Among these, especially when a disconnection occurs, in order to prevent this, the transparent conductive film must be thickened. However, when the transparent conductive film becomes thick like this, the light transmittance of the transparent conductive film inevitably tends to decrease. Further, if there is a protruding portion in the transparent conductive film, the conductive film interval is reduced at that portion, and the drive margin is reduced due to non-uniform driving conditions of the display element.
[0006]
If the surface shape is complicated as described above, the color filter layer portion is likely to be cracked or peeled off. In addition to the light non-reflective layer portion, the color filter layer is lifted also in the vicinity thereof. Therefore, in that portion, the thickness of the color filter layer is larger than in the other portions, and the optical characteristics are different.
[0007]
Therefore, various measures are taken in the manufacturing process to prevent foreign matter from being mixed into the colored pixel or the material for forming the protective layer so that the unevenness is not formed, or to prevent the formation of unevenness when forming the colored pixel and the protective layer. Has been done.
[0008]
However, in reality, it is difficult to form a protective layer without unevenness, and after forming the protective layer, the unevenness formed on the protective layer is flattened. As a method of smoothing minute continuous irregularities on the surface of the color filter, a method of smoothing the surface of the RGB resin film layer or the protective film surface by polishing or applying a smoothing material is generally used. (For example, see Patent Document 1)
[0009]
[Patent Document 1]
JP-A 63-17215 [0010]
[Problems to be solved by the invention]
However, in this method, a minute unevenness may occur again on the smoothed resin film surface depending on the formation condition (film formation condition) of the transparent conductive film, which is a subsequent process. There is a problem that there is no limit and it is limited.
Such minute irregularities, especially protrusions, can cause a short circuit with the opposing conductive film, and can cause serious problems in panel reliability, such as concentration of current and voltage, which impairs panel drive uniformity. There is.
[0011]
The subject of this invention is improving the smoothness of the surface by the side of a transparent conductive film of a color filter with a transparent conductive film of a color display apparatus, and a conductive film surface. The surface of the color filter with a transparent conductive film is smoothed to improve the reliability of the color display device. In the case of a liquid crystal display panel, when the surface of the color filter is made smooth, the thickness of the liquid crystal layer becomes uniform and the display quality is improved.
An object of the present invention is to provide a color filter with a transparent conductive film having an extremely smooth surface and a method for producing the same.
[0013]
[Means for Solving the Problems]
In the first aspect of the present invention, in the color filter having at least a colored layer and a transparent conductive film layer on the substrate, the surface of the transparent conductive film layer is smoothed, and the average of the surface of the transparent conductive film layer A color filter having a surface roughness (Ra) of 30 mm or less.
[0014]
A second aspect of the present invention is a method for producing a color filter, wherein after forming at least a colored layer and a transparent conductive film on a substrate, the surface of the transparent conductive layer is smoothed.
[0015]
According to a third aspect of the present invention, in the method for producing a color filter according to the second aspect, the average surface roughness (Ra) of the transparent conductive layer film surface is set to 30 mm or less by the smoothing treatment of the transparent conductive layer. It is a manufacturing method of the color filter characterized.
[0016]
According to a fourth aspect of the present invention, in the color filter manufacturing method according to the third aspect, the smoothing treatment of the transparent conductive film layer is performed using an abrasive having an average particle size of 50 mm or less. It is a manufacturing method of a filter.
[0017]
According to a fifth aspect of the present invention, in the color filter manufacturing method according to the third to fourth aspects, the smoothing treatment of the transparent conductive film layer is performed using a polyvinyl alcohol-based or polyurethane-based sponge brush. This is a method for manufacturing a color filter.
[0018]
According to the present invention, it is possible to provide a highly reliable color filter that does not cause display defects in a color display device and particularly alignment defects in a liquid crystal display device, and a manufacturing method thereof.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described.
The transparent substrate in the present invention is not particularly limited, and any material can be used as long as it is a material excellent in smoothness and transparency, and is restricted only by the type of display device using a color filter with a transparent conductive film. Is done. From an economical point of view, it is presumed that the material is often selected from glass or a highly transparent plastic material. If the character of the display element permits, in particular, an organic electroluminescence display and an electronic paper can be applied to a flexible film material.
[0020]
The material and forming method of the black matrix, the color filter layer (RGB resin layer), and the material and forming method of the overcoat layer may be selected from materials and forming methods suitable for each display device. In addition, smoothing treatment after the formation of the black matrix and color filter layer (RGB resin layer), for example, polishing, formation of the smoothing layer or both, and smoothing treatment after formation of the overcoat layer, such as polishing, It does not exclude the formation of the smoothing layer or both of them, but if the smoothness is not sufficient due to the material and process, the smoothing process in these previous steps is carried out more actively. Needless to say, a color filter with a transparent conductive film having high smoothness can be obtained.
[0021]
There are no particular restrictions on the material of the transparent conductive film. ITO (indium-tin oxide) zinc oxide, tin oxide, zinc oxide added with aluminum oxide or gallium oxide, tin oxide doped with antimony oxide or fluorine, etc. Either is applicable.
[0022]
The formation process is not particularly restricted, and sputtering widely used industrially because a low-resistance film can be produced on a large-area substrate at a relatively low temperature. Vacuum deposition including activated reactive deposition and high-density plasma-assisted deposition, in which reactive deposition is performed in an atmosphere in which oxygen is introduced using a metal as the evaporation source. A sol-gel method that uses a solution of a compound such as a metal alkoxide as a raw material to form a film by spin coating or heat treatment after dipping. Cluster beam deposition that simultaneously irradiates the substrate with an oxygen cluster ion beam during deposition from a metal or oxide source. A PLD method in which a target surface is struck out with a laser beam to form a film on an opposing substrate. Any forming method can be applied. In the present invention, a very good effect was confirmed in ITO (indium-tin oxide) formed by sputtering under a high temperature finishing condition with a film forming temperature of 200 ° C. and a film thickness of 1600 mm.
[0023]
A black matrix, a color filter layer (RGB resin layer), an ITO (indium-tin oxide) transparent conductive film formed by sputtering under a high-temperature condition under a film forming temperature of 200 ° C. and a film thickness of 1600 mm are formed on glass. A substrate was prepared. The surface roughness is measured using an arithmetic average roughness (hereinafter referred to as Ra) of a roughness curve, which is the arithmetic average of the absolute value of elevation at a measurement length of 128 μm, using a scanning probe microscope AS-7B manufactured by Takano Co., Ltd. It was measured. At this time, the unevenness (Ra) of the color filter surface was about 120 mm before the treatment.
[0024]
Normally, when used in a liquid crystal display device, the unevenness (Ra) can be used as a panel with about 50 mm, and if it is suppressed to 30 mm or less, a highly reliable liquid crystal display device with a sufficient driving margin can be realized. I was able to headline.
The surface smoothing method is to remove the fine irregularities by rubbing the surface of the color filter with a sponge brush that has absorbed the fine particle dispersion, and then remove the fine particle dispersion. .
[0025]
The fine particles subjected to the smoothing treatment were good in average spherical alumina because of few scars unnecessary in terms of material and good polishing efficiency. Silica, acid value cerium, and the like can also be used. The use of particles with many corners caused fine scratches on the substrate to impair the transparency of the transparent conductive film, and the resistance value when the panel was formed was high, and the variation was not reliable. The particle size is preferably 50 nm or less, and the particle shape is preferably spherical. When the particle size is increased, the processing speed is increased. However, when the particle size is 50 nm or more as the resistance value increases and scratches increase, the polishing speed increases, but the number of scratches increases significantly, and the resistance of the transparent conductive film also increases. It rises rapidly. Further, when the particle size is small, polishing scratches are few and polishing with high smoothness is possible. However, when the particle size is 20 nm or less, the processing speed is remarkably slowed.
[0026]
The concentration of the fine particles with respect to the water of the fine particle dispersed water is preferably 0.1 wt% or more, and is 0.3 wt%. When the concentration of the fine particles with respect to the water of the fine particle dispersed water is 0.1 wt% or less, the smoothness is remarkably lowered, and when the concentration of the fine particles with respect to the water of the fine particle dispersed water is 1.0 wt% or more, the transparent conductive film after the smoothing treatment The efficiency of removal from the attached color filter was significantly reduced.
[0027]
As a treatment method, the surface of the color filter was smoothed using a spongy brush using true spherical particles having an average particle diameter of 40 nm or less.
The sponge brush has a structure that easily absorbs the fine particle dispersion, and an open cell or semi-open cell type structure is preferable, and the shape can be a roll, a disk, or the like. The material is preferably a polyvinyl alcohol-based or polyurethane-based material. Specifically, a polyvinyl alcohol roll brush having a porosity of 90% and an Asker C hardness of 10 ° or less, a brand name Berclin, a polyurethane roll brush having a porosity of 80% and an Asker C hardness of 10 °, a trade name Ruby Cell, etc. In the case of a polyvinyl chloride roll brush having a porosity of 75% and an Asker C hardness of 10 ° or less, and an IC roller having a trade name of IC roller, many scratches were generated and it was not suitable for use.
[0028]
The use of a roll brush equipped with roll conveyance was very effective from the viewpoints of line suitability, efficiency, and homogeneity. (Refer to FIG. 1) With respect to the relationship with the speed of the substrate 2, the roll brush 1 can be rotated at a rotational speed of 300 to 450 rpm at a substrate transport speed of 0.3 to 0.5 m / min. It is necessary to consider that the brush rotation is fast so that it does not become the same speed as the substrate. From the viewpoint of efficiency, it goes without saying that the speed can be increased by increasing the number of roll brushes, and the efficiency is improved.
[0029]
The contact amount W of the brush is preferably 5 mm to 30 mm, and if it is 5 mm or less, sufficient polishing cannot be obtained and the smoothness is lowered. On the other hand, if it is 30 mm or more, the torque applied to the rotation of the brush becomes large, the rotation becomes unstable, and the smoothness becomes uneven.
[0030]
Further, the average particle diameter may be divided into two stages in consideration of processing efficiency and product quality. First, the first stage polishing is performed with a fine particle dispersion liquid having an average particle diameter of 50 nm to 40 nm, and then the surface is finished with a fine particle dispersion liquid of 35 nm to 20 nm, whereby the treatment can be efficiently performed with high quality. According to such a method, when the film thickness of the transparent conductive film is about 1600 mm, the surface having a high smoothness with a surface roughness of 10 mm or less after the surface treatment is applied to the transparent conductive film with practical processing efficiency. It can also be obtained without causing a decrease in transmittance or an increase in resistance value.
[0031]
[Example 1]
A color filter in which an RGB layer of about 1.3 μm was formed on glass having a thickness of 0.7 mm and a transparent conductive film of about 1600 mm was further formed was used in the experiment. The surface roughness (Ra) before the experiment was approximately 130 mm.
The color filter was processed with a smoothing device. (Equipment structure is omitted)
Equipment conditions: Conveying speed 0.5m / min Polyvinyl alcohol roll brush 400rpm (Rotating in the same direction as the substrate) Fine particle dispersion: Alumina 0.3wt% (average particle diameter 45nm and 30nm) Smoothing treatment was performed at a particle diameter of 45 nm, and treatment was performed at 30 nm as the second stage. The dispersion was absorbed by a sponge brush and rubbed on the surface of the color filter. After the surface treatment, the substrate was thoroughly rinsed with a sponge brush while being washed with water and dried. When the surface irregularities were measured, it was about 28 mm.
[0032]
As can be seen from these results, the color filter with a transparent conductive film formed on the transparent substrate has a smoothness and a highly reliable color filter with a transparent conductive film by smoothing after the formation of the transparent conductive film. Can be produced.
[0033]
【The invention's effect】
By performing a surface smoothing treatment after forming a transparent conductive film by the processing method according to the present invention, a color filter having no micro unevenness on the surface is stable with a high yield without being affected by the film forming conditions of the transparent conductive film. Can be produced.
[0034]
[Brief description of the drawings]
FIG. 1 schematically illustrates a brush contact amount.
[Explanation of symbols]
1 Roll Brush 2 Color Filter Substrate with Transparent Conductive Film 3 Alumina Dispersed Water (Abrasive)
W Brush contact amount

Claims (5)

In the color filter having at least a colored layer and a transparent conductive film layer on the substrate,
A color filter, wherein the surface of the transparent conductive film layer is smoothed, and the average surface roughness (Ra) of the surface of the transparent conductive film layer is 30 mm or less. After forming at least a colored layer and a transparent conductive film on the substrate,
A method for producing a color filter, wherein the surface of the transparent conductive film layer is smoothed. 3. The method for producing a color filter according to claim 2, wherein the average surface roughness (Ra) of the surface of the transparent conductive layer film is 30 mm or less by the smoothing treatment of the transparent conductive layer. . 4. The method for producing a color filter according to claim 3, wherein the smoothing treatment of the transparent conductive film layer is performed using an abrasive having an average particle diameter of 50 mm or less. 5. The method for producing a color filter according to claim 3, wherein the transparent conductive film layer is smoothed using a polyvinyl alcohol or polyurethane sponge brush.

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