JPH04338718A - liquid crystal display device - Google Patents

Abstract

PURPOSE:To reduce orientation defects and improve the outward appearance of a display by making the top surface of a data line or scanning line and the surface of a picture element smooth and flat and covering the data line and scanning line with an insulator. CONSTITUTION:As for the active matrix liquid crystal display device, a projection is formed by forming a transparent insulating film below a picture element electrode 3 or a recessed part is formed by etching the data line 2 and scanning line 1 previously so as to flatten the top surface of the data line 2 or scanning line 1 and the transparent picture element electrode 3. Then the data line 2 and scanning line 1 are covered with the insulator 4. When the insulator 4 uses a transparent material and is used for a transmission type liquid crystal display body while covered with metal, a black frame on an opposite substrate side for hiding the data line 2 and scanning line 1 is preferably eliminated.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to the structure of active matrix liquid crystal display devices.

0002

2. Description of the Related Art An example of the structure of a conventional active matrix liquid crystal display device is as shown in FIG. First, the switch elements for each pixel are made, then the data lines and scanning lines are formed, and finally the pixel electrodes are made. The switch element of each pixel is placed at the intersection of the data line and the scan line. In such a structure, the step difference between the data line or scanning line and the pixel surface or pixel electrode is 5000 to 1
It is about 0,000 Å. For this reason, the direction of the rubbing treatment for orienting the liquid crystal is preferably a direction that does not cross the step, and has been performed in the direction of the data line or scanning line. Also,
When the pixel pitch is 50 μm or less, the orientation becomes particularly poor.

0003

The above-mentioned prior art has the disadvantage that due to the difference in level between the data line or scanning line and the pixel surface or pixel electrode, the lines are not rubbed evenly during rubbing, resulting in poor alignment.

[0004] An object of the present invention is to make the step difference smooth and flat so that it can be rubbed evenly during rubbing, and to improve the display appearance by increasing the contrast and improving the alignment force.

[0005]

The above object is achieved by making one of the data line or the scanning line smooth and flat with the pixel surface or the pixel electrode, and covering the data line and the scanning line with an insulator.

[0006]

[Embodiment] Hereinafter, an embodiment of the present invention will be explained with reference to FIGS. 1 and 2. In order to flatten the upper surfaces of the data lines 2 and scanning lines 1 and the pixel electrode surface 3, either a transparent insulating film 5 is placed under the pixel electrodes to form convex portions, or the data line and scanning line portions are etched in advance. It is necessary to make a recess. Next, by covering the data line 2 and the scanning line 1 with an insulator 4, the level difference between the pixel and the transparent electrode surface 3 is made extremely flat to 2000 Å or less, as shown in FIG. This makes it possible to perform the alignment process extremely evenly when performing alignment processing on the surface of the pixel, for example, by rubbing. As the insulator 4, a material such as a polyimide resin film is used, for example.

It is also possible to use an opaque insulator as the insulator 4 covering the data line 2 or scanning line 1. As a result, when used in transmissive liquid crystal displays, etc.,
The black frame on the opposing substrate side for hiding the data line 2 and scanning line 1 can be eliminated. As the opaque insulator 4 used here, an opaque polyimide resin film is used. Also, Figure 2
The insulator may be covered with a metal 7 as shown in FIG. This also allows the same effect as when using an opaque insulator to be obtained. The metal 7 used is, for example, chromium. The thickness of the metal film is preferably 1000 to 2000 Å in order to reduce the difference in level from the pixel surface.

[0008]

According to the present invention, since the surfaces of data lines or scanning lines and pixels or pixel electrodes are smooth and flat, it is possible to achieve extremely uniform alignment during alignment processing such as rubbing. This reduced alignment defects and improved contrast ratio. Furthermore, the alignment process can be performed regardless of the direction of the data lines or scanning lines. By making the material in which the data lines and scanning lines are embedded opaque, it is possible to eliminate the light-shielding black frame on the opposing substrate side that hides the data lines and scanning lines, making alignment during the panel assembly process easier.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing data lines, scanning lines, and flattening of a pixel surface according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example in which an insulator covering data lines and scanning lines is covered with a metal film, which is an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a pixel structure of a conventional active matrix liquid crystal display device.

[Explanation of symbols]

1 Scanning line 2 Data line 3 Transparent pixel electrode 4. Insulating material covering data lines and scanning lines 5 Transparent insulator 6 Pixel switch element

Claims (4)

[Claims] 1. An active matrix liquid crystal display device in which a plurality of data lines and a plurality of scanning lines intersect perpendicularly, and a switch element and a pixel electrode are provided at the intersections, in which at least one of the data lines or the scanning lines is located on the surface of a pixel or A liquid crystal display device characterized in that the data line and the scanning line are smooth and flat with the pixel electrode, and the data line and the scanning line are covered with an insulator. 2. The liquid crystal display device according to claim 1, wherein the insulator covering the data line and the scanning line is a polyimide resin film. Claim 3: Claim 2 wherein the polyimide film is opaque.
The liquid crystal display device described. 4. The liquid crystal display device according to claim 1, wherein the insulating material covering the data line or the scanning line is covered with metal.