JPH11237622A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate a disclination line generated with a lateral electric field between a pixel electrode and a drain line from the pixel electrode. SOLUTION: Mutually contiguous parts of mutually contiguous color filter elements 13 are put one over the other. Consequently, the interval between the peripheral part of a right-side pixel electrode 4 in the figure and a common electrode 14 faces it is narrower than the interval between the center part of the pixel electrode 4 and the opposite common electrode 14. Consequently, the longitudinal electric field intensity between the peripheral part of the right- side pixel electrode 4 and the common electrode 14 becomes relatively strong and then the lateral electric field at the peripheral part of the pixel electrode 4 becomes relatively weak correspondingly, so that the disclination line 17 can be separated from the pixel electrode 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art FIG. 3 is a partial sectional view of an example of a conventional liquid crystal display device. This liquid crystal display device includes a transparent lower substrate 1 and an upper substrate 11 made of glass or the like. On the upper surface of the lower substrate 1, a thin film transistor 2 as a switching element and a gate insulating film 3 are provided. In this case, although not shown, a gate line is provided at a predetermined position between the lower substrate 1 and the gate insulating film 3 so as to be connected to the thin film transistor 2. At a predetermined position on the upper surface of the gate insulating film 3, a pixel electrode 4 is provided so as to be connected to the thin film transistor 2. An overcoat film 5 is provided on the periphery of the pixel electrode 4 and on the upper surfaces of the thin film transistor 2 and the gate insulating film 3. A drain line 6 is connected to the thin film transistor 2 at a predetermined position on the upper surface of the overcoat film 5. An alignment film 7 is provided on the upper surface of the overcoat film 5 including the drain line 6 and the upper surface of the pixel electrode 4.

On the other hand, a black mask 12 made of chromium is provided on the lower surface of the upper substrate 11, and red and
Green and blue color filter elements 13 are provided, a common electrode 14 is provided on a lower surface thereof, and an alignment film 1 is provided on a lower surface thereof.
5 are provided. Then, the lower substrate 1 and the upper substrate 1
Reference numeral 1 is attached to each other via a sealing material (not shown). Also, both substrates 1 and 11 inside the sealing material
Liquid crystal 16 is sealed between the alignment films 7 and 15.

In this liquid crystal display device, adjacent color filter elements 13 are separated from each other. Next, the reason will be described. When the red, green, and blue color filter elements 13 are formed by photolithography, it is extremely difficult to make the adjacent color filter elements 13 in close contact with each other in consideration of the alignment accuracy of the photomask. . Therefore, if the adjacent color filter elements 13 are separated from each other, high accuracy is not required for the alignment of the photomask.

[0005]

However, when the adjacent color filter elements 13 are separated from each other, the common electrode 14 and the pixel electrode between the adjacent color filter elements 13 (in this case, the pixel electrode on the right side in FIG. 3). The distance between the peripheral portion of the pixel electrode 4 and the peripheral portion of the pixel electrode 4 (in this case, the distance in the vertical direction, the same applies hereinafter) is the central portion between the common electrode 14 and the pixel electrode 4 in the color filter element 13 forming region on the right side in FIG. Therefore, the vertical electric field strength between the peripheral portion of the pixel electrode 4 and the common electrode 14 becomes weaker in accordance with the increase of the interval. Therefore, the horizontal electric field strength between the pixel electrode 4 and the drain line 6 increases in accordance with the decrease in the vertical electric field strength. For example, as shown by a dashed line in FIG. The line 17 approaches the pixel electrode 4 side. As a result, the area where the disclination occurs becomes large, and when the black mask 12 is provided so as to cover the area where the disclination occurs, there is a problem that the aperture ratio decreases. It is an object of the present invention to separate a disclination line from a pixel electrode.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method of combining a substrate provided with a pixel electrode on one surface thereof and another substrate provided with a common electrode on a surface of the one substrate opposed to the one surface. In a liquid crystal display device in which liquid crystal is sealed in between, a distance between a peripheral portion of the pixel electrode and the common electrode opposed thereto is set between a central portion of the pixel electrode and the common electrode opposed thereto. Is smaller than the interval. According to the present invention, the distance between the peripheral portion of the pixel electrode and the common electrode facing the pixel electrode is smaller than the distance between the central portion of the pixel electrode and the common electrode facing the pixel electrode. The vertical electric field strength between the periphery of the electrode and the common electrode becomes relatively strong, and accordingly the horizontal electric field strength around the pixel electrode becomes relatively weak. It can be separated from the electrodes.

[0007]

FIG. 1 is a sectional view showing a main part of a liquid crystal display device according to a first embodiment of the present invention. In this figure, the same reference numerals are given to the same parts as those in FIG. 3, and the description thereof will be appropriately omitted. In this liquid crystal display device, a black mask 12 made of chrome is provided on the lower surface of an upper substrate 11 as in the conventional case, and red, green, and blue color filter elements 13 are formed on the lower surface of each other in the black mask 12 portion. They are provided in an overlapping manner. That is, the color filter element 13 on the left side of FIG.
Of the color filter element 13 on the right side of the black mask 12 is superposed on the lower surface of the black mask 12 so as to extend to the vicinity of the right end of the black mask 12.
The black mask 12 is provided so as to be superimposed on the lower surface of the color filter element 13 on the left side. Also in this case, the common electrode 14 is provided on the lower surface of the color filter element 13 and the alignment film 15 is provided on the lower surface.
Is provided. Note that a predetermined peripheral portion of the pixel electrode 4 on the right side in FIG. 1 is provided on the upper surface of the thin film transistor 2.

As described above, in this liquid crystal display device, the adjacent color filter elements 13 are overlapped with each other at the black mask 12 so that the adjacent color filter elements 13 are overlapped with each other. The distance between the common electrode 14 and the peripheral portion of the pixel electrode (the pixel electrode on the right side in FIG. 1, the same applies hereafter) 4 in the designated area is set to the color filter element 1 on the right side in FIG.
The distance between the common electrode 14 and the central portion of the pixel electrode 4 in the formation region 3 can be made smaller. As a result,
The vertical electric field intensity between the peripheral portion of the pixel electrode 4 and the common electrode 14 becomes relatively strong, and accordingly, the horizontal electric field intensity at the peripheral portion of the pixel electrode 4 becomes relatively weak, and consequently disclination. The line 17 can be separated from the pixel electrode 4; As a result, the area where the disclination occurs becomes smaller, and the opening of the black mask 12 can be enlarged accordingly, and therefore the aperture ratio can be increased. Moreover, in this liquid crystal display device, the predetermined peripheral portion of the pixel electrode 4 is provided on the upper surface of the thin film transistor 2, so that the vertical electric field strength between the peripheral portion of the pixel electrode 4 and the common electrode 14 is further increased. be able to.

FIG. 2 is a sectional view of a main part of a liquid crystal display device according to a second embodiment of the present invention. In this figure, the same reference numerals are given to the same names as those in FIG.
The description is omitted as appropriate. In this liquid crystal display device, red, green and blue color filter elements 1 are provided on the lower surface of the upper substrate 11.
3 are provided apart from each other, and the adjacent portions of the adjacent color filter elements 13 and the upper substrate 11 therebetween.
A black mask 12 made of resin black is provided on the lower surface of the substrate. In this case, the thickness of the black mask 12 is substantially the same as the thickness of the color filter element 13. Also in this case, the common electrode 14 is provided on the lower surface of the color filter element 13 and the black mask 12,
An alignment film 15 is provided on its lower surface. Note that FIG.
A predetermined peripheral portion of the pixel electrode 4 on the right side of the right side of FIG.

As described above, in this liquid crystal display device, the black masks 12 made of resin black having substantially the same thickness as the color filter elements 13 are provided so as to overlap the adjacent color filter elements 13. Therefore, except for the central portion between the color filter elements 13, 13, the common electrode 14 and the pixel electrode 4 in the region where the color filter element 13 and the black mask 12 overlap each other.
Can be made narrower than the distance between the common electrode 14 and the center of the pixel electrode 4 in the color filter element 13 forming region on the right side of FIG. In this case, the central portion between the color filter elements 13 has substantially the same thickness as the portion where the black mask 12 is not formed, in other words, the portion facing the pixel electrode 4. Since the vertical electric field strength is relatively high in the region where the filter element 13 and the black mask 12 are superimposed, the horizontal electric field strength in this region is relatively low, and the disclination line 17 is connected to the pixel electrode. 4. As a result, also in the second embodiment, as in the first embodiment, the area where the disclination occurs is reduced, and accordingly, the opening of the black mask 12 can be enlarged, and accordingly, the aperture ratio can be increased. Can be.

In the second embodiment, the case where the thickness of the black mask 12 is made substantially the same as the thickness of the color filter element 13 has been described. However, the present invention is not limited to this. It may be thicker than the thickness of the element 13. In the second embodiment, the case where the color filter element 13 is provided on the lower surface of the upper substrate 11 and the black mask 12 is provided on the lower surface has been described. However, the present invention is not limited to this. 12, and a color filter element 13 may be provided on the lower surface thereof. Further, in the second embodiment, the case where adjacent portions of the adjacent color filter elements 13 are separated from each other is described. However, the present invention is not limited to this, and the adjacent portions of the adjacent color filter elements 13 may be separated. They may overlap each other.

[0012]

As described above, according to the present invention, the distance between the peripheral portion of the pixel electrode and the common electrode facing the pixel electrode is set between the central portion of the pixel electrode and the common electrode facing the same. , The vertical electric field strength between the peripheral portion of the pixel electrode and the common electrode becomes relatively strong, and accordingly, the horizontal electric field strength at the peripheral portion of the pixel electrode becomes relatively large. Therefore, the disclination line can be separated from the pixel electrode, and as a result, the area where the disclination occurs can be reduced, the opening of the black mask can be enlarged, and the aperture ratio can be increased. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of an example of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower substrate 2 Thin film transistor 4 Pixel electrode 6 Drain line 11 Upper substrate 12 Black mask 13 Color filter element 14 Common electrode

Claims (3)

[Claims] 1. A liquid crystal is sealed between one substrate having a pixel electrode on one surface and another substrate having a common electrode on a surface of the one substrate facing the one surface. In the liquid crystal display device, an interval between a peripheral portion of the pixel electrode and the common electrode opposed thereto is smaller than an interval between a central portion of the pixel electrode and the common electrode opposed thereto. A liquid crystal display device characterized by the above-mentioned. 2. A color filter element is provided between the other substrate and the common electrode corresponding to the pixel electrode, and adjacent portions of adjacent color filter elements are overlapped with each other. The liquid crystal display device according to claim 1, wherein: 3. A color filter element is provided between the other substrate and the common electrode so as to correspond to the pixel electrode, and a black mask made of resin black is provided between adjacent color filter elements. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is provided so as to overlap an adjacent portion.