JPH05150266A - Liquid crystal display device - Google Patents

Abstract

(57) [Summary] [Structure] A plurality of image signal wirings 1 and scanning signal wirings 2 are provided so as to intersect with each other, and at each intersection of the image signal wirings 1 and scanning signal wirings 2, a pixel electrode 3 and this pixel electrode 3 A thin film transistor 4 for supplying an image signal to
A liquid crystal display device, in which a counter electrode for applying a voltage to a liquid crystal material is provided in a portion facing the pixel electrode 3, wherein the image signal wiring 1 or the scanning signal wiring 2 is connected to the pixel electrode 3 via an insulating film. Coated. As a DC component is apparently generated in the vertical direction between the image signal wiring 1 or the scanning signal wiring 2 and the pixel electrode, the DC component is not directly applied to the liquid crystal layer, and the liquid crystal layer is eliminated. The disclination does not occur and the image quality is not deteriorated thereby. Therefore, a high-definition liquid crystal display device in which pixels are miniaturized can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to an active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art In a conventional active matrix type liquid crystal display device, as shown in FIGS. 3 and 4, a plurality of image signal wirings 31 and scanning signal wirings 32 are provided so as to intersect with each other, and the image signal wirings 31 and scanning are performed. Pixel electrodes 33 and thin film transistors 34 for supplying image signals to the pixel electrodes 33 are provided in a matrix at each intersection with the signal line 32, and a counter electrode for applying a voltage to a liquid crystal material at a portion facing the pixel electrodes 33. 35, the image signal wiring 3 is provided.
The supply of the image signal from 1 to the pixel electrode 33 through the thin film transistor 34 is controlled by turning on / off the transistor 34 based on the scanning signal of the scanning signal wiring 32, and the counter electrode signal is transmitted to the counter electrode 35. The image signal and the counter electrode signal are supplied to the liquid crystal layer 36.
To drive the liquid crystal.

[0003]

However, in this conventional liquid crystal display device, the image signal wiring 31, the scanning signal wiring 32, and the pixel electrode 33 are formed on the same surface of the substrate 37 with a minute interval. Therefore, D is provided between the image signal wiring 31, the scanning signal wiring 32, and the pixel electrode 33.
There is a problem that the C component is generated, and the DC component causes the disclination in the molecular arrangement of the liquid crystal layer 36 to deteriorate the image quality. In the disclination part, it becomes difficult for light to pass therethrough to obtain a beautiful black color. This phenomenon has a larger effect as the pixel size becomes smaller, and is a cause of hindering high definition.

[0004]

The liquid crystal display device according to the present invention has been made in view of such problems, and is characterized in that a plurality of image signal wirings and scanning signal wirings are provided. Pixel electrodes and thin film transistors for supplying image signals to the pixel electrodes are provided in a matrix at each intersection of the image signal wirings and the scanning signal wirings, and a liquid crystal material is provided in a portion facing the pixel electrodes. In the liquid crystal display device provided with a counter electrode for applying a voltage to, the image signal wiring and / or the scanning signal wiring is covered with the pixel electrode via an insulating film.

[0005]

With the above-described structure, a DC component is apparently generated in the vertical direction between the image signal wiring or the scanning signal wiring and the pixel electrode. Therefore, this DC component is directly applied to the liquid crystal layer. This eliminates the occurrence of disclination in the liquid crystal layer and the resulting deterioration of image quality. Therefore, a high-definition liquid crystal display device in which pixels are miniaturized can be realized.

[0006]

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view of a pixel electrode portion showing an embodiment of a liquid crystal display device according to the present invention, in which 1 is an image signal wiring,
Reference numeral 2 is a scanning signal wiring.

A pixel electrode 3 and a thin film transistor 4 for supplying an image signal to the pixel electrode 3 are provided in a matrix at each intersection of the image signal wiring 1 and the scanning signal wiring 2. The scanning signal wiring 2 is connected to the gate electrode 4a of the thin film transistor 4, and the image signal wiring 1 is connected to the source / drain electrode 4b of the thin film transistor 4. That is, from the image signal wiring 1 to the thin film transistor 4
The supply of the image signal to the pixel electrode 3 via is controlled by turning on / off the transistor 4 based on the scanning signal of the scanning signal wiring 2. An insulating film (not shown) is naturally formed at each intersection of the image signal wiring 1 and the scanning signal wiring 2 so as not to cause a short circuit. The pixel electrode 3 is formed to extend over the image signal wiring 1 and the scanning signal 2a of the next stage so as to cover the image signal wiring 1 and the scanning signal 2a of the next stage.

That is, as shown in the sectional view of FIG. 2, the pixel electrode 3 is formed so as to cover the image signal wiring 1 through the insulating film 8. When the pixel electrode 3 is thus formed so as to cover the image signal wiring 1 with the insulating film 8 in between, a DC component is generated between the pixel electrode 3 and the image signal wiring 1, but this DC component is apparent. This DC component is not applied to the liquid crystal material on the pixel electrode 3 in the direction perpendicular to the upper substrate 7. The scanning signal wiring 2a at the next stage shown in FIG. 1 is also covered with the pixel electrode 3 in the same manner. Further, the scanning signal wiring 2 of the main stage is covered with the pixel electrode 3a of the previous stage, and the image signal wiring 1a of the next stage is covered with the pixel electrode 3b of the next stage.

Further, as shown in FIG. 2, the pixel electrode 3
A counter electrode 5 for applying a voltage to the liquid crystal material by the pixel electrode 3 is provided in a portion facing the pixel electrode 3, and an image signal supplied to the pixel electrode 3 and a counter electrode signal supplied to the counter electrode 5 are supplied to the liquid crystal. It is applied to the layer 6 to drive the liquid crystal 6.

The pixel electrode 3 as described above is formed of a transparent conductive film such as tin oxide or indium tin oxide, but the image signal wiring 1, the scanning signal wiring 2, and the thin film transistor 4 are formed.
After forming the image signal wiring 1 and the scanning signal wiring 2
It may be formed by, for example, a sputtering method so as to cover the.

In the above embodiment, the image signal wiring and the scanning signal wiring are covered with one pixel electrode. However, the present invention is not limited to this embodiment, and the image signal wiring with two adjacent pixel electrodes is used. Also, the scanning signal wiring may be covered from both sides. Thus, by covering the image signal wiring and the scanning signal wiring from both sides with two adjacent pixel electrodes, it is possible to reduce the black matrix shielding area on the other surface.

[0012]

As described above, according to the liquid crystal display device of the present invention, since the image signal wiring or the scanning signal wiring is covered with the pixel electrode through the insulating film, the image signal wiring or the scanning signal wiring is provided. A DC component is apparently generated in the vertical direction between the pixel electrode and the pixel electrode, the DC component is not directly applied to the liquid crystal layer, and the disclination occurs in the liquid crystal layer, and thereby the image quality is improved. It will not deteriorate. Therefore, a high-definition liquid crystal display device in which pixels are miniaturized can be realized.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 3 is a plan view showing a conventional liquid crystal display device.

FIG. 4 is a cross-sectional view showing a conventional liquid crystal display device.

[Explanation of symbols]

1 ... Image signal wiring, 2 ... Scan signal wiring, 3 ...
-Pixel electrode, 4 ... Thin film transistor, 8 ... Insulating film.

Claims (1)

[Claims] 1. A plurality of image signal wirings and scanning signal wirings are provided so as to intersect with each other, and a pixel electrode and a thin film transistor for supplying an image signal to the pixel electrode are provided at each intersection of the image signal wiring and the scanning signal wiring. In a liquid crystal display device, which is provided in a matrix, and a counter electrode for applying a voltage to a liquid crystal material is provided in a portion facing the pixel electrode, the image signal wiring and / or the scanning signal wiring is provided through the insulating film. A liquid crystal display device characterized by being coated with.