JP3078554B2 - Reflective liquid crystal display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a structure of a light shielding layer of an active matrix liquid crystal display device.

[Conventional technology]

The conventional light-shielding layer needs to cover the entire active element in the case of a transmission type active matrix liquid crystal display device, and the reflection type simple matrix liquid crystal display device has no built-in active element. I should have covered it.

Some reflective active matrix liquid crystal display devices are described in the 1989 IEICE Autumn National Convention Lecture Papers, Vol. This covers the signal lines and the scanning lines with a light shielding layer as shown in FIG.

[Problems to be solved by the invention]

In a liquid crystal display device, a portion where a liquid crystal driving electrode such as a signal line, a scanning line, or an active element cannot be installed cannot drive the liquid crystal, so that the contrast is reduced around the portion. For this reason, a light-shielding layer is provided so that the portion where the liquid crystal cannot be driven is made invisible to increase the contrast.However, in a reflection type active matrix liquid crystal display device, the through hole of the liquid crystal drive electrode becomes concave and does not become flat in a normal method. The contrast is reduced due to irregular reflection. Since the method of filling the through-hole portion is complicated, there is a problem that the contrast cannot be easily improved.

The present invention solves this problem, and an object of the present invention is to provide a structure in which the contrast is easily improved.

[Means for solving the problem]

According to the present invention, a liquid crystal layer is sealed between a pair of substrates,
In a reflective liquid crystal display device, a plurality of drive electrodes formed in a matrix and a plurality of switching elements connected to the drive electrodes are arranged on one of the pair of substrates. The electrodes are connected to each other through through holes formed in an insulating film on the switching element. On the other substrate of the pair of substrates, a position facing the concave portion of the drive electrode caused by the through holes. A light-shielding film is formed thereon.

〔Example〕

FIG. 1 is a sectional view of the liquid crystal display device of the present invention. First
In order from the bottom of the figure, the drive electrode side glass substrate 101, 102 to 109 constituting the active element, the signal line 111a or the scanning line 111
b, liquid crystal drive electrode 110, liquid crystal 112, common electrode 113, light shielding layer 11
4. The common electrode side glass substrate 115.

FIGS. 2 and 3 show this as viewed from the common substrate side. The light shielding layer 114 covers a part of the liquid crystal driving electrode 110 at the same time as covering the signal line 111a and the scanning line 111b. The liquid crystal driving electrode which also serves as a light reflecting surface, which is a component of the present invention, has a concave portion formed in a through hole portion which is a contact point with an active element. The incident light is irregularly reflected by the concave portion, and as a result, the contrast is reduced. When this concave portion is covered with a light-shielding layer, it is always displayed in black, but by displaying only the important portion, a decrease in contrast can be prevented.

This light-shielding layer may be a single layer as shown in FIG. 1, or may be integrated with a color filter as shown in FIG. 4 when a color filter is provided. Further, the light-shielding layer can be formed on the liquid crystal side of the common electrode. Further, in the figure, the light-shielding portion covering the concave portion of the liquid crystal drive electrode is not an independent region, but it can be made independent of the light-shielding portion of the scanning line or the signal line.

1, 2, 3, 4, and 5 each show an FET as an active element, it is a CMOSEFT, or a dual gate having two gate electrodes to provide redundancy. The light-shielding portion of the present invention is effective if the liquid crystal driving electrode also serving as the light reflecting surface has a concave portion generated during the device formation process even when the device structure is changed, such as forming a device or an inverted stagger type device. It is.

In addition, although polycrystalline silicon has been described as a material of the liquid crystal driving element, it may be amorphous silicon, single crystal silicon, or another substance.

〔The invention's effect〕

As described above, in the present invention, since the light-shielding film is formed on the other substrate of the pair of substrates at a position facing the concave portion of the drive electrode, the concave portion of the drive electrode disturbs the molecular arrangement of the liquid crystal. However, the disordered molecular arrangement near the concave portion can be covered with the light shielding film on the counter substrate side. Therefore, it is possible to prevent a decrease in contrast due to a disorder in the molecular arrangement.

[Brief description of the drawings]

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 as viewed from the common electrode side. FIG. 3 is a plan view in which the liquid crystal display device of the present invention is 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 sectional view of a conventional reflection type active matrix liquid crystal display device. 101 glass substrate on drive electrode side 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

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-64-68729 (JP, A) JP-A-1-156724 (JP, A) JP-A-1-104051 (JP, U)

Claims (1)

(57) [Claims] A liquid crystal layer is sealed between a pair of substrates,
In a reflective liquid crystal display device, a plurality of drive electrodes formed in a matrix and a plurality of switching elements connected to the drive electrodes are arranged on one of the pair of substrates. The electrodes are connected to each other through through holes formed in an insulating film on the switching element. On the other substrate of the pair of substrates, a position facing the concave portion of the drive electrode caused by the through holes. A reflection type liquid crystal display device, wherein a light shielding film is formed on the liquid crystal display device.