JPH03150532A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve in contrast by providing a light shield film on one of two opposite substrates which has a common electrode and covering signal lines, scanning lines, and the recessed parts of liquid crystal driving parts on the other substrate with the light shield layer. CONSTITUTION:The light shield layer 114 is formed on the side of the substrate 115 which has the common electrode between the two opposite substrates, and the light shield layer 114 covers the signal lines 11a and scanning lines 11b and also covers part of the liquid crystal driving electrodes 110. Namely, the liquid crystal driving electrodes 110 serving as light reflecting surfaces have the recessed parts at through hole parts which are contacts for active elements, and the recessed parts reflect incident light irregularly, so that the contrast decreases. The recessed parts are covered with the light shield layer 114 and then displayed darkly, but only important parts are displayed to prevent contrast from decreasing. Consequently, contrast can easily be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a light shielding layer of a reflective active matrix liquid crystal display device. In some cases, it is necessary to cover the entire active element, whereas in reflective simple matrix liquid crystal display devices, only the signal lines and scanning lines need to be covered because they do not have active elements built-in.

In addition, some reflective active matrix liquid crystal display devices are described in Section 5.30 of the Proceedings of the 1989 Autumn National Conference of the Institute of Electronics, Information and Communication Engineers. This is the fifth
As shown in the figure, the signal lines and scanning lines are covered with a light shielding layer.

[Problem to be solved by the invention]

In a liquid crystal display device, the liquid crystal cannot be driven in areas such as signal lines, scanning lines, and active elements where liquid crystal driving electrodes cannot be installed, so that contrast decreases in the surrounding areas. For this reason, a light-shielding layer is provided to hide the areas where the liquid crystal cannot be driven and increase the contrast. However, in reflective active matrix liquid crystal display devices, the through holes of the liquid crystal drive electrodes are concave and not flat in the normal method. , the contrast decreases due to diffused reflection. Since the method of filling the through-hole portion is complicated, there is a problem in that the contrast cannot be easily improved.

The present invention solves this problem, and its purpose is to provide a structure that can easily improve contrast.

[Means to solve the problem]

In the liquid crystal display device of the present invention, in a reflective active matrix liquid crystal display device, among two opposing substrates,
It is characterized by a structure in which a light shielding layer is provided on the side of the substrate having one common electrode, and covers the concave portions of the signal lines, scanning lines, and liquid crystal drive electrodes on the other substrate.

〔Example〕

FIG. 1 is a sectional view of a liquid crystal display device of the present invention.

From the bottom of FIG. 1, the drive electrode side glass substrate 101, active elements 102 to 109, and signal line 111a.
Or the scanning line 111b, the liquid crystal drive electrode 110, the liquid crystal 11
2, a common electrode 113, a light shielding layer 114, and a common electrode side glass substrate 115.

FIGS. 2 and 3 show this as seen from the common board side. The light shielding layer 114 covers the signal line 111a and the scanning line 111b, and also partially covers the liquid crystal drive electrode 110.

A liquid crystal driving electrode that also serves as a light reflecting surface, which is a component of the present invention, has a recess formed in a through-hole portion that is a contact point with an active element. The incident light is diffusely reflected by these four parts, resulting in a decrease in contrast. If these four parts are covered with a light-shielding layer, the image will always be displayed in black, but by displaying only the important parts, a decrease in contrast can be prevented.

This light shielding layer may be a single layer as shown in Figure 1, or
If a color filter is provided, it may be integrated with it as shown in FIG. It is also possible to form a light shielding layer on the liquid crystal side of the common electrode. Further, in the figure, the light-shielding portions covering the four portions of the liquid crystal drive electrodes are not independent regions, but it is also possible to make them independent from the light-shielding portions of the scanning lines and signal lines.

In Figures 1, 2, 3, 4, and 5, FETs are shown as active elements, but these are 0MO3
Even when changing the device structure, such as using an FET, a dual-gate type with two gate electrodes for redundancy, or an inverted staggered structure, the liquid crystal drive electrode that also serves as a light-reflecting surface remains unchanged. The light shielding portion of the present invention is effective if the device has a concave portion generated during the device formation process.

In addition, polycrystalline silicon was mentioned as a material for liquid crystal drive elements, but this is different from amorphous silicon, single crystal silicon,
Or other substances may be used.

〔Effect of the invention〕

The liquid crystal display device of the present invention described above is a reflective active matrix liquid crystal display device in which a light shielding layer is provided on one of the two opposing substrates having a common electrode, and a light shielding layer is provided on the side having a common electrode on the other substrate. The structure that covers the concave portions of the signal line, scanning line, and liquid crystal drive electrode has the effect of improving contrast.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a liquid crystal display device of the present invention. FIG. 2 is a plan view of the liquid crystal display device of the present invention viewed from the common electrode side. FIG. 3 is a plan view of the liquid crystal display device of the present invention, enlarged by one pixel from the common electrode side. FIG. 4 is a diagram of a liquid crystal display device of the present invention in which a color filter and a light shielding layer are integrated. FIG. 5 is a cross-sectional view of a conventional reflective active matrix liquid crystal display device. 101...Drive electrode side glass substrate 102...Source 103...Polycrystalline silicon 104...Drain 105...Interlayer insulating film 106...Gate insulating film 107...Gate 108...Source Electrode 109...Drain electrode 110...Liquid crystal drive electrode 111a...Signal line 111b...Scanning line 112...Liquid crystal 113...Common electrode 114...Light shielding layer 115...Common electrode side Glass substrate 281-

Claims (1)

[Claims] In reflective active matrix liquid crystal display devices,
A light-shielding layer provided on the side of one of the two opposing substrates that has a common electrode, and a signal line on the other substrate,
A liquid crystal display device characterized by a structure that covers scanning lines and concave portions of liquid crystal drive electrodes.