JPH05249485A - Active matrix liquid crystal display having thin-film transistor for switching - Google Patents

Abstract

PURPOSE:To improve an opening rate by disposing pixel electrodes consisting of transparent electrode films formed on a glass substrate and disposing thin-film transistors (TFTs) within the wiring regions of these pixel electrodes. CONSTITUTION:The pixel electrodes 11 consisting of the transparent electrode films are provided on a glass substrate 10. These pixel electrodes 11 are connected to n<+> layers (sources) 16 doped with phosphorus in order to obtain the ohmic contact of the TFTs via source lines 18. Gate lines 12 are wired in an (x) direction on the glass substrate 10. Gate insulating layer 15 are formed on the gate lines 12 and semiconductor layers 14 consisting of amorphous silicon, etc., are provided thereon. The n<+> layers (sources) 16 doped with the phosphorus in order to obtain the ohmic contact and the n<+> layers (drains 17) doped with the phosphorus in order to obtain the ohmic contact are provided on these semiconductor layers 14. Drain lines 13 are provided thereon; in a (y) direction in this embodiment. As a result, such thing that the picture element part are partly occupied by TFTs is eliminated and the opening rate is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix liquid crystal display having a thin film transistor used for switching pixels such as a liquid crystal display and a liquid crystal shutter.

[0002]

2. Description of the Related Art FIG. 3 is a plan view of a liquid crystal display having a conventional pixel switching thin film transistor. As shown in this figure, 21 is a pixel electrode made of a transparent electrode film, which is connected to the source of the thin film transistor. Reference numeral 22 is a gate line, and 23 is a drain line to which an image signal is applied. Reference numeral 24 is a thin film transistor (hereinafter referred to as TFT) for turning on / off the pixel electrode, each electrode of the gate, source and drain, a semiconductor layer 25 such as amorphous silicon, and a gate which also serves as an insulating layer of a gate line and a drain line. It is composed of an insulating layer 26. Here, usually TFT
Are arranged in the pixel region near the intersection of the gate line and the drain line.

[0003]

However, in such a TFT arrangement, since the TFT occupies a part of the pixel area, there arises a problem that the aperture ratio is lowered, which causes colorization and redundancy. Along with the increase in the number of TFTs, there has been a big problem. SUMMARY OF THE INVENTION It is an object of the present invention to provide an active matrix liquid crystal display having a switching thin film transistor having a large aperture ratio by arranging TFTs in the regions of the gate line and the drain line in order to eliminate the above-mentioned decrease in aperture ratio. And

[0004]

In order to achieve the above object, the present invention provides an active matrix liquid crystal display in which each pixel on a glass substrate has a switching thin film transistor, and a transparent electrode film formed on the glass substrate. The pixel electrode and the thin film transistor are arranged in the wiring region of the pixel electrode.

[0005]

According to the present invention, the pixel electrode made of the transparent electrode film formed on the glass substrate and the thin film transistor are arranged in the wiring region of the pixel electrode, and the gate electrode is used as it is without being drawn out into the pixel. , Forming a channel mainly on the intersection area of the gate line and the drain line. Therefore, unlike the conventional case, the TFT does not occupy a part of the pixel portion, and the aperture ratio can be improved.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a plan view of a liquid crystal display showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of the liquid crystal display. In the figure, 11 is a glass substrate 10.
Pixel electrodes made of a transparent electrode film formed above, 12 are gate lines, and 13 are drain lines. Further, 14 is a semiconductor layer such as amorphous silicon, 15 is a gate insulating layer, 16 is an n ⁺ layer (source) doped with phosphorus for obtaining ohmic contact, and 17 is doped with phosphorus for obtaining ohmic contact. The n ⁺ layer (drain), 18 is a source line to which the pixel electrode 11 is connected.

The manufacturing process may be the same as the conventional example. Here, the channel of the TFT exists inside the drain line. 1 and 2, the glass substrate 10
A pixel electrode 11 made of a transparent electrode film is provided on the upper side, and the pixel electrode 11 is connected via a source line 18 to a phosphorus-doped n ⁺ layer (source) 16 for obtaining ohmic contact of the TFT. Further, the gate line 12 is wired on the glass substrate 10 in the x direction here. A gate insulating layer 15 is formed on the gate line 12, and a semiconductor layer 14 such as amorphous silicon is provided on the gate insulating layer 15. On the semiconductor layer 14, a phosphorus-doped n ⁺ layer (source) 16 for obtaining an ohmic contact and a phosphorus-doped n ⁺ layer (drain) 17 for obtaining an ohmic contact are provided. Then, the drain line 13 is formed in the y direction.

FIG. 4 is a plan view of a liquid crystal display showing another embodiment of the present invention. In the figure, 31 is a pixel electrode made of a transparent electrode film formed on a glass substrate, 32 is a gate line, and 33 is a drain line. Further, 34 is a semiconductor layer such as amorphous silicon, 35 is a gate insulating layer, and 36 is a source line to which the pixel electrode 31 is connected. In this way, when it is desired to increase the channel width, as shown in FIG.
The gate may be branched from the gate line 32.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention, and these modifications are not excluded from the scope of the present invention.

[0010]

As described above in detail, according to the present invention, the channel of the TFT is arranged in the same region as the drain line or the gate line. The TFT is not occupied and the aperture ratio can be improved.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a plan view of a liquid crystal display including a conventional pixel switching thin film transistor.

FIG. 4 is a plan view of a liquid crystal display showing another embodiment of the present invention.

[Explanation of reference signs] 10 glass substrate 11,31 pixel electrode 12,32 gate line 13,33 drain line 14,34 semiconductor layer 15,35 gate insulating layer 16 n ⁺ layer (source) 17 n ⁺ layer (drain) 18, 36 source line

Claims (2)

[Claims] 1. An active matrix liquid crystal display having a switching thin film transistor in each pixel on a glass substrate, wherein (a) a pixel electrode made of a transparent electrode film formed on the glass substrate and (b) wiring of the pixel electrode. An active matrix liquid crystal display having a switching thin film transistor, characterized in that a thin film transistor is arranged in a region. 2. The active matrix liquid crystal display having a switching thin film transistor according to claim 1, wherein the wiring region is a region where a gate line and a drain line intersect with each other.