JP2700802B2 - Support substrate for color LCD panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a color filter and a color filter on a transparent substrate such as glass, which is one of two support substrates sandwiching a liquid crystal. The present invention relates to a support substrate for a color liquid crystal panel having a transparent electrode line thereon, and more particularly to a technique for preventing disconnection of a transparent electrode line.

(Prior Art) In general, a color liquid crystal panel uses a liquid crystal as an optical shutter and can perform color display by using a color filter having three primary color pixels of red (R), green (G), and blue (B). This is a display device.

In such a color liquid crystal panel, the liquid crystal is sandwiched between two support substrates, and the color filter is disposed on the side facing the liquid crystal in order to eliminate the effect of color mixing due to parallax.

A transparent electrode is provided on each of the support substrates. In order to apply an effective driving voltage to the liquid crystal, a transparent electrode is preferably provided on the color filter for a support substrate having a color filter. . The above is described in, for example, JP-A-61-51126.

(Problem to be Solved by the Invention) When a transparent electrode is provided on the upper layer of a color filter, in a simple matrix system or an active matrix system using a two-terminal element such as MIM, the transparent electrode is
It is formed in a line for each column of each color pixel.

However, such a line-shaped transparent electrode, that is, a transparent electrode line is liable to be disconnected, and it is necessary to take measures to prevent such disconnection. Disconnection often occurs at the step portion when each color pixel of the color filter is thickened. Therefore, as a measure to prevent disconnection, thinner color filters,
Alternatively, it is conceivable to reduce the level difference by covering the color filter with a thick transparent protective film. However, such measures cannot provide sufficient color density,
Alternatively, it is not preferable because formation of a transparent protective film becomes difficult.

The present inventor studied the mechanism of such disconnection, and found that the disconnection was caused by the penetration of the etching solution from the edge portion of the transparent electrode line, and also by the penetration from the step portion having poor adhesion to the base. I knew it was there.

The present invention has been made in consideration of the above-described examination results, and its purpose is to prevent disconnection of the transparent electrode line even when the color pixels of the color filter are thick and the transparent protective film is thin. An object of the present invention is to provide a technology that can be effectively prevented.

(Summary of the Invention) In the present invention, adjacent color pixels of a color filter are separated from each other by a predetermined distance, a flat boundary area is provided between the color pixels, and each transparent electrode also serves as an electrode and a wiring for each color pixel. By setting the width of the line to be larger than the size of each color pixel, each transparent electrode line completely covers the color pixels in each column, and the edges on both sides are located on the flat boundary region. I have to.

Thereby, the edge of each transparent electrode line is always located on a flat surface, so that the adhesiveness thereof is improved, and the permeation of the etching solution from the edge can be prevented.

(Example) The transparent substrate 10 which is a transparent glass plate has two upper and lower surfaces parallel to each other, and each surface 10a, 10b is flat. An upper surface 10a is a side facing the liquid crystal, and a light-shielding layer 20 capable of blocking transmitted light is provided on the surface 10a. This light-shielding layer 20 can be formed of a polyimide resin containing a black dye, or a metal material such as chromium. The light-shielding layer 20 is etched to form each color pixel, but it is preferable that the thickness of the light-shielding layer 20 itself be thin, for example, 1.5 μm or less, in order to reduce a step caused by the etching. In that regard, it is preferable to form the layer 20 using a material having a high light-shielding property.

The size of the portion 22 removed by etching is, for example,
The size of each color pixel, such as 150 μm × 150 μm, is slightly smaller than, for example, 170 μm × 170 μm. At this time, a sufficient space having a width of, for example, 50 μm is provided between the cutout portions 22.

Red (R), green (G), and blue (B) color pixels 30 are formed on the light shielding layer 20. Each color pixel 30
It is formed by a photolithography technique similarly to the light-shielding layer 20, using a polyimide resin material containing a coloring material or the like. Each color pixel 30 is formed so as to completely cover each cutout portion 22, but it is better to make the overlap with the light shielding layer 20 as small as possible. This is because it is desired to provide a sufficient space for the flat light shielding layer 20 between the adjacent color pixels 30. Color pixel
Assuming that the overlap between the light-shielding layer 20 and the light-shielding layer 20 is 10 μm on both the left and right sides, the space on the light-shielding layer 20 that forms the boundary area between the color pixels 30
It is about 30 μm.

On the transparent substrate 10 on which the light shielding layer 20 and the pixels 30 of each color are formed, a transparent protective film 40 is further formed so as to cover the whole. The transparent protective film 40 is made of an organic material such as polyimide.
Alternatively, an inorganic material such as silicon dioxide can be used. The transparent protective film 40 is usually formed to be considerably thick in order to reduce surface irregularities, but here, for example, is relatively thin, for example, about 1 μm. Therefore, the step due to each color pixel 30 is not sufficiently mitigated by the transparent protective film 40. However, the portion of the boundary area between the color pixels 30 is flattened accordingly since the lower layer is flat.

On such a transparent protective film 40, a transparent electrode line 50 is placed. Each transparent electrode line 50 is formed by a conventional method of forming a film of a transparent electrode material such as ITO by sputtering or the like, and then etching it by a photolithography method. In the present invention, the edge portions 50a, 50
Position b over a flat border area. Therefore, the width of each transparent electrode line 50 is, for example, 180 μm and
Larger than the dimensions. In any case, each transparent electrode line 50 runs on the uneven surface of each color pixel 30 and the light-shielding layer 20, but in the screen, the edge portions 50a and 50b are located on a flat boundary area in any portion. Located in. Thereby, both edges 50a, 50b of each transparent electrode line 50 are
It adheres well to the underlying transparent protective film 40. Therefore,
The etching liquid does not penetrate from the edge portions 50a and 50b, and the transparent electrode line 50 does not break.

Although the light-shielding layer 20 is provided in the illustrated embodiment, the light-shielding layer 20 may be omitted depending on the size of each color pixel or the type of the display device.

Further, in the embodiment, each color pixel is aligned in a straight line in the X and Y directions. For example, as shown in JP-A-59-9636, each color pixel is arranged in each row or each column. For example, they can be shifted by a half pitch. In that case, each transparent electrode line becomes zigzag, but those adjacent to each other run in parallel. The present invention can be applied to such a case.

Further, regarding the transparent electrode film 40, the transparent electrode line 50
In the case where the color filter is not damaged by the forming step, for example, when each color pixel 30 is sufficiently cured, it can be formed very thin or can be omitted.

(Effect of the Invention) In the present invention, the edge portions 50a and 50b of the transparent electrode line 50 are provided.
Are positioned on a flat surface, so that the edges 50a and 50b have good adhesion with the base, and therefore,
The disconnection of the transparent electrode line 50 can be prevented without the etchant penetrating from the edge portion. In particular, since the boundary region between the respective color pixels 30 is surely and sufficiently flat according to the flat surface 10a of the transparent substrate 10, the effect of preventing disconnection according to the present invention is reliable.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a portion taken along line II-II of FIG. 10 transparent substrate, 20 light-shielding layer, 30 color pixels, 40
Transparent protective film, 50: Transparent electrode line, 50a, 50b: Edge part.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-43729 (JP, A) JP-A-61-46931 (JP, A) JP-A-61-51127 (JP, A)

Claims (3)

(57) [Claims] 1. A transparent substrate having a flat surface, which is one of two support substrates sandwiching a liquid crystal, and each color pixel formed in a matrix on one surface facing the liquid crystal side of the transparent substrate. In a support substrate of a color liquid crystal panel having a plurality of transparent electrode lines that run in parallel with each other and serve also as electrodes and wirings for each color pixel in the upper layer of each color pixel, adjacent ones of the color pixels are separated from each other, There is a flat boundary area between each color pixel, and the width of the transparent electrode line is larger than the size of each color pixel, and each transparent electrode line completely covers the color pixels of each column, and the edges on both sides thereof A support substrate for a color liquid crystal panel, wherein the portion is located in the flat boundary region. 2. The support substrate for a color liquid crystal panel according to claim 1, wherein the flat boundary region is formed of a light-shielding layer covering one surface of the transparent substrate. 3. The supporting substrate for a color liquid crystal panel according to claim 1, wherein a transparent protective film covers each color pixel, and each transparent electrode line is formed on the transparent protective film. .