JP2015069072A - Color filter and manufacturing method of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive layer capable of maintaining conductivity that can secure voltage necessary for drive, originated from a border such as between pixels, with no occurrence of an ITO crack and having necessary transmissivity.SOLUTION: A color filter includes a black matrix 3, a pigmented layer 2 composed of three primary colors and a transparent conductive layer sequentially formed on a transparent substrate 1. The transparent conductive layer formed on the black matrix is thicker than the transparent conductive layer formed on the pigmented layer. Thickness of the transparent conductive layer formed on the black matrix is 1400Å or more.

Description

  The present invention relates to a color filter used for a flat panel display, a flexible display, etc., such as a liquid crystal display element and an EL element, which are used for a television, a personal computer, a portable terminal and the like.

  Recently, with the spread of OA equipment and portable small TVs, liquid crystal display elements and EL elements have been put into practical use. Among them, the liquid crystal display element has features such as extremely light weight and thinness, low price and low power consumption driving, and good compatibility with an integrated circuit.

  In a liquid crystal display element, two conductive plates, a common driving substrate and a segment driving substrate, are arranged in parallel, and liquid crystal is injected between them to display an arbitrary design by an electro-optic effect. Yes.

  A material having dielectric anisotropy is arranged to display an image using the property of being oriented when placed on an electric field, and a transparent electrode and an alignment film formed on a black matrix, a colored layer, The structure is such that liquid crystal is injected into a liquid crystal cell formed by surrounding the laminated upper and lower glass substrates with a sealing material.

As the LCD becomes larger, the transparent electrodes formed in a stripe shape become thinner and longer, and a potential difference is generated between the voltage application side (IC drive side) and the opposite side when a voltage is applied. The potential difference is caused by a line voltage drop because ITO (indium tin oxide) itself used as a transparent conductive layer has a minimum surface resistance of 10 to 30 Ω / cm ² when only a transparent electrode is used, As a result, a difference in image quality occurs between both sides of the display screen, causing image quality defects.

  The main characteristics required for ITO are transmittance and resistance. Increasing the ITO thickness increases the ITO transmittance, but conversely increases the sheet resistance by decreasing the ITO thickness. Resulting in.

  In addition, by making the ITO film thin, ITO cracks are likely to occur. Especially when the ITO film thickness is less than 1400 mm, ITO cracks occur starting from the boundary between pixels, etc., and abnormal resistance values and irregularities occur. This causes a problem as a color filter.

JP 2005-84493 A

  The present invention has been made in view of the above-described circumstances, maintains the conductivity that can secure the voltage necessary for driving, does not generate ITO cracks starting from boundaries such as between pixels, and has the necessary transmittance. It is in providing the transparent conductive layer which has.

As means for solving the above problems, the invention according to claim 1 is a color filter in which a black matrix on a transparent substrate, a colored layer composed of three primary colors and a transparent conductive layer are sequentially formed,
The color filter is characterized in that the transparent conductive layer provided on the black matrix is thicker than the transparent conductive layer provided on the colored layer.

  The invention according to claim 2 is the color filter according to claim 1, wherein the transparent conductive layer provided on the black matrix has a thickness of 1400 mm or more.

The invention according to claim 3 is a method for producing a color filter according to claim 1 or 2,
After forming the transparent conductive layer on the entire surface of the transparent substrate on which the black matrix and the colored pixels composed of the three primary colors are formed,
A method for producing a color filter, comprising: applying a positive resist on the transparent conductive layer; irradiating UV light from the transparent substrate side; developing the positive resist; and etching the transparent conductive layer on the colored pixels. is there.

The invention according to claim 4 is the method for producing a color filter according to claim 1 or 2, wherein
After forming the transparent conductive layer on the entire surface of the transparent substrate on which the black matrix and the colored pixels composed of the three primary colors are formed,
Applying a negative resist on the transparent conductive layer, irradiating UV light through a photomask having an opening only on the black matrix, developing the negative resist, and etching the transparent conductive layer on the colored pixels It is a manufacturing method of the color filter characterized.

  According to the present invention, the influence of the resistance of the transparent conductive layer and the generation of cracks due to the increase in size of the color filter and the like, and when the transparent conductive layer is thickened, the colored layer portion becomes yellowish and the transmittance is reduced. Can also be prevented.

It is the conceptual diagram which showed the structure of the color filter of this invention. The upper view of FIG. 1 is a plan view, and the lower view is a cross-sectional view taken along line AA. It is the process conceptual diagram which showed the manufacturing method using the positive resist of the color filter of this invention. It is the process conceptual diagram which showed the manufacturing method using the negative resist of the color filter of this invention. It is the conceptual diagram which showed the structure of the conventional color filter, and the generation | occurrence | production location of a crack. The upper drawing of FIG. 4 is a plan view, and the lower drawing is a cross-sectional view taken along line AA.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings and examples. FIG. 1 shows the configuration of the color filter of the present invention, in which a transparent conductive layer 4 is provided on the colored layer 2 and the black matrix 3, and the thickness of the transparent conductive layer 4 is the same as the thickness on the colored layer 2. On the other hand, the thickness on the black matrix 3 is increased.

  FIG. 2 shows a flow of the manufacturing method according to the first embodiment of the present invention. As the transparent substrate 1, glass was used and the black photosensitive resin composition was apply | coated to the whole surface. Next, UV light (ultraviolet light) 8 was exposed through a black matrix-shaped mask, and alkali development was performed to form a black matrix 3.

  Next, a red photosensitive resin composition was applied to the entire surface. Subsequently, ultraviolet rays were exposed through a colored layer-shaped mask, and alkali development was performed to form a red colored layer 2. Similarly, green and blue colored layers 2 were formed (a).

  Next, a transparent conductive layer (ITO) 4 having a thickness of 1500 mm was formed on the entire surface of the colored layer 2 by sputtering. On top of that, a positive resist (photolytic resist) 5 was applied on the transparent conductive layer 4 and irradiated with exposure light from the substrate side (b).

  The positive resist 5 was developed to form the positive resist 5 on the transparent conductive layer on the black matrix (c).

  The portion where the positive resist 5 is not formed on the transparent conductive layer is etched with an etching solution containing oxalic acid as a main component, the transparent conductive layer thickness on the colored layer 2 is set to 1200 mm, and the transparent conductive layer on the black matrix 3 The thickness of 4 was 1500 mm. In addition, according to this manufacturing method, a photomask is not necessary for resist exposure.

  FIG. 3 shows a flow of the manufacturing method of Example 1 of the present invention, and a black photosensitive resin composition was applied on the entire surface of the transparent substrate 1. Subsequently, ultraviolet rays were exposed through a photomask having a shape 7 and alkali development was performed to form a black matrix 3.

  Subsequently, the red photosensitive resin composition was apply | coated to the whole surface. Subsequently, ultraviolet rays were exposed through a mask having a colored layer shape, and alkali development was performed to form a red colored layer 2. Similarly, green and blue colored layers were formed. Next, a transparent conductive layer (ITO) 4 having a thickness of 1500 mm was formed on the entire surface including the colored layer and the black matrix by a sputtering method (a).

  On top of that, a negative resist 6 was applied on the transparent conductive layer 4 and irradiated with UV light 8 through a photomask 7 having an opening in the shape of the thickened portion of the transparent conductive layer (b).

  The negative resist 6 was developed, and the negative resist 6 was formed on the rack matrix 3 of the transparent conductive layer 4 laminated on the black matrix 3 (c).

  A portion where the negative resist 6 is not formed on the transparent conductive layer, that is, the transparent conductive layer 4 on the colored layer 2 is etched with an etching solution mainly composed of oxalic acid, and the transparent conductive layer 4 on the colored layer 2 is etched. The thickness was 1200 mm (d).

  According to this manufacturing method, the shape of the thickened portion of the transparent conductive layer 4 can be made different from the shape of the black matrix 3.

<Comparative Example 1>
In the same manner as in Example 1 and Example 2, after forming the black matrix 3 and the colored layer 2, a transparent conductive layer (ITO) 4 was formed on the entire surface with a thickness of 1500 mm using a sputtering method. Next, without providing a resist on the transparent conductive layer 4, etching was performed with an etching solution containing oxalic acid as a main component, so that the thickness of the transparent conductive layer 4 was 1200 mm (see FIG. 4).

<Comparative Example 2>
In the same manner as in Example 1 and Example 2, after forming the black matrix 3 and the colored layer 2, a transparent conductive layer (ITO) 4 was formed on the entire surface with a thickness of 1500 mm using a sputtering method.

<Evaluation>
With respect to the produced Examples 1 and 2 and Comparative Examples 1 and 2, the microscopic observation and the transmission spectral characteristics of the colored layer 2 part were measured. The results are shown in Table 1.

In the case where the thickness of the transparent conductive layer 4 on the black matrix 3 was 1500 mm, no generation of the ITO crack was observed including the ITO crack starting from the boundary between the pixels. Further, in the case where the thickness of the transparent conductive layer 4 on the colored layer 2 was adjusted to 1200 mm, the yellow component was not found in the measurement of the spectral characteristics, but in the case where the thickness was 1500 mm, the influence of the yellow component was observed.

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Colored layer 3 ... Black matrix 4 ... Transparent conductive layer 5 ... Positive resist 6 ... Negative resist 7 ... Photomask 8 ... UV light 9 ···crack

Claims (4)

A color filter in which a black matrix, a colored layer composed of three primary colors, and a transparent conductive layer are sequentially formed on a transparent substrate,
A color filter, wherein the transparent conductive layer provided on the black matrix is thicker than the transparent conductive layer provided on the colored layer.   The color filter according to claim 1, wherein the transparent conductive layer provided on the black matrix has a thickness of 1400 mm or more. A method for producing a color filter according to claim 1 or 2,
After forming the transparent conductive layer on the entire surface of the transparent substrate on which the black matrix and the colored pixels composed of the three primary colors are formed,
A method for producing a color filter, comprising: applying a positive resist on the transparent conductive layer; irradiating UV light from the transparent substrate side; developing the positive resist; and etching the transparent conductive layer on the colored pixels. A method for producing a color filter according to claim 1 or 2,
After forming the transparent conductive layer on the entire surface of the transparent substrate on which the black matrix and the colored pixels composed of the three primary colors are formed,
Applying a negative resist on the transparent conductive layer, irradiating UV light through a photomask having an opening only on the black matrix, developing the negative resist, and etching the transparent conductive layer on the colored pixels A method for producing a color filter.