JPH0450925A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To increase the rate of opening and to obtain high image quality by connecting 1st and 2nd TFT's to the same image element electrode at one connecting part and 1st and 2nd TFT's to the same signal line at one connecting part. CONSTITUTION:The drain D11a of TFT 11a and the drain D11b of TFT 11b are connected to an image element electrode 11 at a connecting part 121. The source S11b of the TFT 11b and the source S22a of TFT 22a are connected to a signal line X2 at a connecting part 122. Since the number of such connecting parts can be reduced, the area of an opening 100 is increased and high image quality can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a liquid crystal display device, and particularly to an active matrix type device.

(Conventional technology) As a conventional active matrix type liquid crystal display device,
“Nikkei Electronics December 15, 1986 issue, p.
, 193-210, and its schematic structure is shown in Fig. 4. Signal lines Xi, X2 . X3
．． ... are wired, and scanning lines Y1 . . . are wired in the row direction. ．． Y2. Y
3. ...is wired.

Further, pixel electrodes 11 are arranged in a matrix, and thin film transistors (hereinafter referred to as
(referred to as TPT).

For example, a thin film transistor 11a is arranged at the intersection of the signal line X1 and the scanning line Y1, a TPTI 1b is arranged at the intersection of the signal line X2 and the scanning line Y2, and two TFTI 1a and TFTI 1b are arranged for one pixel electrode 11. 11b is provided. In this way, redundancy is provided so that even if one of them does not operate normally, the other can be used for relief.

Then, in TFTI 1a, the gate G11a is connected to the scanning line Y.
1, the source S] and 1a are connected to the signal line X1, and the drain Dlla is connected to the pixel electrode 11.

Further, the gate Gflb of TPTllb is connected to the scanning line Y2, the source Sllb is connected to the signal line X2, and the drain Dllb is connected to the same pixel electrode 11.

As a result, a video signal is input from the signal line X1 or X2 to the TPTl 1a or 11b selected by the selection pulse sent to the scanning line Y1 or Y2, and its output is applied to the pixel electrode 11.

(Problem to be solved by the invention) However, since two TPTs are arranged for each pixel electrode, the number of connections between the train of each TPT and the pixel electrode, as well as between the source and the signal line X increases. Ta. As shown in FIG. 5, for example, the pixel electrode 11 is connected to the drain Dlla of TFTlla through a contact hole 202, and is connected to the drain Dllb of TFTl, 1b through a contact hole 201. When the number of contact holes increases in this way, the area of the openings 200 that can transmit light or liquid crystal decreases, resulting in a problem that the screen becomes dark and image quality deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device that can increase the aperture ratio and achieve high image quality.

[Structure of the invention]

(Means for Solving the Problem) The present invention provides a first pixel electrode arranged on a first insulating substrate on a pixel electrode or matrix, scanned by a first scanning line, and inputted with a signal from a first signal line. and a second TP scanned by the second scanning line and receiving a signal from the second signal line.
T is connected to each pixel electrode, a counter electrode is arranged on the surface of a second insulating substrate provided oppositely on the second insulating substrate, and A liquid crystal display device in which a liquid crystal is sandwiched between a substrate and a connecting portion of a first TPT to a pixel electrode and a second TPT.
The connection portion of the first TPT and the connection portion of the second TPT to the same signal line are also shared.

(Function) In order to provide redundancy for each pixel electrode, the first and second T
PT is connected, but the first to the same pixel electrode
Since the connection part between the first TPT and the second TPT is shared, and the connection part between the first TPT and the second TPT for the same signal line is also shared, the number of connections is reduced and the number of openings is reduced. This results in improved image quality and improved image quality. Further, since the semiconductor thin films of each TPT are connected and short-circuited, there is no need to cause dielectric breakdown during the process of implanting impurity ions into the semiconductor thin film during manufacturing, thereby improving manufacturing yield.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a liquid crystal display device according to this embodiment. This embodiment is characterized in that the number of connection parts is reduced by sharing the connection part between the TPT and the pixel electrode, as well as the connection part between the TPT and the signal line, and the aperture ratio is improved. be.

FIG. 1 shows the circuit configuration of a liquid crystal display device according to this embodiment. Pixel electrode Co1 and drain Dll of TFTI1a
The connection portion 121 is shared by the connection portion between the pixel electrode 11 and the drain Dllb of the TPTI 1 b. Similarly, the connection between the signal line X2 and the source 5llb of TFTllb, and the connection between the signal line X2 and the TFT22a
The connection with the source S 22a or the connection 122 is shared.

A specific planar structure in this case is shown in FIG.

Drain Dl of TFTl 1 a and T P T l
The drain DIlb of Ib is connected to the conductive semiconductor thin film 103 through a shared contact hole 10.
1 is connected to the pixel electrode 11 .

Drain Dllb of TPTllb for signal line X2
Similarly, the connection between and the drain D22a of the TFT22a is as follows.
This is done in a shared contact hole 102. In this way, by sharing the connection parts, the number of connections is reduced and the area of the aperture 100 is increased to realize a bright screen and achieve high image quality. Specifically, compared to the area of the conventional opening 200 shown in FIG. 5, the area has increased by about 20%.

In addition, since the semiconductor thin films of each TPT are short-circuited, dielectric breakdown due to chatter bulges does not occur when impurity ions are implanted during manufacturing, and the electrostatic breakdown voltage is improved, thereby improving the yield rate.

The other embodiment shown in FIG. 3 corresponds to the case where the storage capacity 11] is provided. In this case as well, TPTl 1
Drain D lla of a and train Dl of TPTllb
It is connected to the pixel electrode 11 through a shared contact hole 10u such as lb. However, here, the common electrode 1]2 of the storage capacitor 111 and the pixel electrode 11 are also connected to each other by sharing this contact hole 101.

The embodiments described above are merely examples and do not limit the present invention. For example, TPT can be polycrystalline silicon, amorphous silicon, cadmium selenium (C
It can be applied to devices using TPT made of any material such as dSe).

〔Effect of the invention〕

As explained above, according to the present invention, the connecting parts between the TPT and the pixel electrode, as well as between the TPT and the signal line, are shared and the aperture ratio is improved, making it possible to realize a bright and high-quality screen. At the same time, since the semiconductor thin films of each TPT are connected and short-circuited, there is no need to cause dielectric breakdown during the process of implanting impurity ions into the semiconductor thin film, and the manufacturing yield can be improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a plan view showing the structure of the device,
FIG. 3 is a circuit diagram showing the structure of a liquid crystal display device according to another embodiment of the present invention, FIG. 4 is a circuit diagram showing the structure of a conventional liquid crystal display device, and FIG. 5 is a circuit diagram showing the structure of the device. FIG. 11-...Pixel electrode, lla, llb, 22a-...T
FT, Dlla, Dllb, D22a
...Drain, 5lla, 5llb, 5
22a-=source, 101°102...contact hole, 103...semiconductor thin film, 100.110...
Opening portion, 111... Holding capacitor, 112... Common electrode, Xl, , X2, X3... Signal line, Yl, Y2. Y
3...Scanning line. Qi 1 figure

Claims (1)

[Claims] Pixel electrodes are arranged in a matrix on a first insulating substrate, a first thin film transistor scanned by a first scanning line, and a signal inputted from a first signal line; A second thin film transistor scanned by a scanning line and receiving a signal from a second signal line is connected to each of the pixel electrodes, and a second thin film transistor provided oppositely on the second insulating substrate is connected to each pixel electrode. In a liquid crystal display device in which a counter electrode is disposed on a surface of an insulating substrate, and a liquid crystal is sandwiched between the first insulating substrate and the second insulating substrate, the first thin film transistor is connected to the same pixel electrode. A connecting portion and a connecting portion of the second thin film transistor are shared, and a connecting portion of the first thin film transistor and a connecting portion of the second thin film transistor are shared with respect to the same signal line. LCD display device.