JPH05241197A - LCD display panel - Google Patents

Abstract

(57) [Abstract] [Objective] An active matrix type liquid crystal display panel having a thin film transistor for switching in each pixel, and providing a plurality of TFTs in each pixel to promote defect-free, high definition and high brightness. The object is to provide an improved liquid crystal display panel. When forming a TFT 74 in an active matrix type liquid crystal display panel, at least two TFTs 74 connected to the same pixel electrode 73 are arranged at right angles with one corner of the connected pixel electrode 73 interposed therebetween. To configure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display panel having a switching thin film transistor for each pixel, and more particularly, a liquid crystal display having a plurality of thin film transistors for each pixel to promote defect-free operation. The present invention relates to high definition and high brightness of a panel.

A 10-inch class medium-definition liquid crystal display panel has already been put into practical use and is used as a display element for a personal computer, a word processor, etc. In recent years, a high-definition liquid crystal display panel that can be used for a high-density display television, a workstation, etc. The practical application of is strongly desired.

However, a high-definition liquid crystal display panel used as a display element in a high-density display television or the like has about three times as many pixels as a medium-definition liquid crystal display panel.
The size of the pixel is halved, and further promotion of defect-free and higher brightness is required.

Therefore, a plurality of thin film transistors (referred to as TFTs) are provided for each pixel to promote further defect-free operation, and at the same time, an active matrix type liquid crystal display panel (liquid crystal display panel) having high definition and high brightness is achieved. Is abbreviated).

[0005]

2. Description of the Related Art FIG. 3 is a schematic view showing a layer structure of a liquid crystal display device, and FIG. 4 is a plan view showing an arrangement of conventional TFTs.

In FIG. 3, an active matrix type liquid crystal display device has a TFT substrate 2 facing each other through a liquid crystal layer 1.
And a liquid crystal display panel composed of a CF substrate 3 and a polarizing plate 4 attached to the outsides of the TFT substrate 2 and the CF substrate 3, respectively.

The TFT substrate 2 has a large number of pixel electrodes 22 and TFTs 23 arranged in a matrix on a glass substrate 21, and the pixel electrodes 22 correspond to columns or rows via one or two TFTs 23. It is connected to the gate bus 24 and the drain bus 25.

On the other hand, the CF substrate 3 has a common electrode 32 formed on the glass substrate 31, and the common electrode 32 is connected to, for example, a ground terminal. In the case of a color liquid crystal display device, color filters 33 corresponding to the three primary colors are formed at positions corresponding to the pixel electrodes 22.

The scan driver 5 connected to all the gate buses 24 sequentially selects one gate bus 24 and supplies a scanning voltage. The data driver 6 connected to all the drain buses 25 sequentially selects one drain bus 25 and supplies the data voltage.

When a predetermined scanning voltage is supplied to the selected gate bus 24, all T's connected to the gate bus 24 are selected.
The FT 23 is activated, a data voltage is supplied to the pixel electrode 22 via the TFT 23 connected to the selected drain bus 25, and the pixel is lit.

However, the TF connected to the pixel electrode 22
If there is only one T23, the pixel will not light up if the TFT23 becomes defective. Therefore, one pixel electrode is adopted with a redundant configuration.
22 is connected to the same gate bus 24 and drain bus 25 via two TFTs 23.

In FIG. 4, the conventional liquid crystal display panel is TF.
T23 is parallel to the long side of the pixel electrode 22 and 1 at both ends of the long side.
For example, even if one of the TFTs 23 becomes defective, the data voltage can be supplied to the pixel electrode 22 via the other TFT 23.

That is, the gate electrodes of the two TFTs 23 on the gate bus 24 which are simultaneously selected by the scan driver 5.
26 is connected and the drain electrodes 27 of the two TFTs 23 are connected.
Are connected to the same drain bus 25, and the source electrode 28 is connected to the same pixel electrode 22.

[0014]

The definition and brightness of the liquid crystal display panel depend on the area ratio of the blinkable area in the display area, that is, the aperture ratio. For example, the area where the TFT is formed cannot be blinked, and if the area where the TFT is formed is large, realization of high brightness is hindered. Further, since the number of TFTs increases in proportion to the improvement in definition, widening the formation area of TFTs impedes realization of high definition.

In order to realize high definition and high brightness of such a liquid crystal display panel, it is necessary to reduce the TFT formation region as much as possible. However, in the conventional liquid crystal display panel, two TFTs connected to the same pixel electrode are arranged at both ends of the long side, and as shown by the broken line in FIG. 4, the blinkable area associated with the aperture ratio is extremely narrow. There was a problem.

It is an object of the present invention to provide a liquid crystal display panel in which a plurality of TFTs are provided for each pixel to promote defect-free, high definition and high brightness.

[0017]

FIG. 1 is a plan view showing a main part of a liquid crystal display panel according to the present invention. Note that the same object is denoted by the same symbol throughout the drawings.

The above problem is solved by a plurality of orthogonal drain buses 71.
And a plurality of pixel electrodes 73 formed in a region surrounded by the gate bus 72 and a plurality of TFTs 74 formed near the intersection of the drain bus 71 and the gate bus 72, and each pixel electrode 73 has an independent drain. In a liquid crystal display panel connected to the drain bus 71 and the gate bus 72 via at least two TFTs 74 having electrodes 75, at least two TFTs 74 connected to the same pixel electrode 73 when forming the TFTs 74 are connected. This is achieved by the liquid crystal display panel of the present invention in which the pixel electrodes 73 are arranged at right angles with one corner therebetween.

[0019]

In FIG. 1, by arranging at least two TFTs at right angles with one corner of a pixel electrode interposed therebetween, a plurality of TFTs connected to the same pixel electrode are conventionally provided by one TF.
It becomes possible to accommodate in the area where T was formed.

That is, it is possible to realize a liquid crystal display panel in which a plurality of TFTs are provided for each pixel to promote defect-free and high definition and high brightness.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 2 is a plan view showing another embodiment of the present invention.

In FIG. 1, the liquid crystal display panel according to the present invention has a plurality of orthogonal drain buses 71 and gate buses 72 formed on a glass substrate 21, and one region is surrounded by each drain bus 71 and gate bus 72. One pixel electrode 73 and two TFTs 74 are formed.

Two TFTs 74 connected to the same pixel electrode 73
Are formed in the vicinity of the intersections because they are driven by the same drain bus 71 and the gate bus 72. ing.

The first TFT 74 whose source electrode 76 is parallel to the short side of the pixel electrode 73 uses the gate bus 72 as a gate electrode, and the drain electrode 75 is parallel to the short side of the pixel electrode 73. Drain bath through the formed bifurcation 77
Connected to 71.

In the second TFT 74 in which the source electrode 76 is parallel to the long side of the pixel electrode 73, the drain electrode 75 is close to the drain bus 71, and the gate electrode 78 is extended and connected to the gate bus 72. In addition, the drain electrode 75 is directly connected to the drain bus 71.

By arranging the TFTs at right angles in this way, it becomes possible to form two TFTs in the area which was conventionally occupied by one TFT, and the blinkable area linked to the aperture ratio is indicated by a broken line in the figure. As shown, it is greatly expanded to realize high definition and high brightness.

In FIG. 2, according to another embodiment of the present invention, a plurality of orthogonal drain buses 71 and gate buses 72 are formed on the glass substrate 21, and the drain buses 71 and the gate buses 72 are surrounded by one area. Each pixel electrode 73 and two TFTs 74 are formed.

Two TFTs 74 connected to the same pixel electrode 73
Are driven by the same drain bus 71 and the gate bus 72, and are formed in the vicinity of the intersection, and the source electrodes 76 of the two TFTs 74 arranged in parallel with the short side of the pixel electrode 73 are the pixel electrodes.
It connects to the short side of 73.

The two TFTs 74 in which the source electrode 76 is parallel to the short side of the pixel electrode 73 utilize the gate bus 72 as a gate electrode, and the drain electrode 75 is parallel to the short side of the pixel electrode 73. Drain bath through the formed bifurcation 77
Connected to 71.

By arranging the TFTs in parallel with the short sides of the pixel electrodes in this way, two TFTs are formed in the area conventionally occupied by one TFT, and a blinkable area linked to the aperture ratio is shown by a broken line in FIG. Further, as shown in, it can be further expanded to realize high definition and high brightness.

In each of the above embodiments, the gate bus is used as the gate electrode, but the gate electrode is formed separately from the gate bus, and the gate electrode is extended and connected to the gate bus parallel to the gate electrode. However, it goes without saying that the same effect can be obtained.

[0032]

As described above, according to the present invention, it is possible to provide a liquid crystal display panel in which a plurality of TFTs are provided for each pixel to promote defect-free, high definition and high brightness.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of a liquid crystal display panel according to the present invention.

FIG. 2 is a plan view showing another embodiment of the present invention.

FIG. 3 is a schematic view showing a layer structure of a liquid crystal display device.

FIG. 4 is a plan view showing a layout of a conventional TFT.

[Explanation of symbols]

 71 Drain bus 72 Gate bus 73 Pixel electrode 74 TFT 75 Drain electrode 76 Source electrode 77 Branch limb 78 Gate electrode

Claims (2)

[Claims] 1. A plurality of pixel electrodes (73) formed in an area surrounded by a plurality of orthogonal drain buses (71) and a gate bus (72), the drain bus (71) and the gate bus (72). ) Has a plurality of thin film transistors (74) formed in the vicinity of the intersection, each of the pixel electrodes (73) is an independent drain electrode (75)
In forming an thin film transistor (74) in an active matrix type liquid crystal display panel which is connected to the drain bus (71) and the gate bus (72) through at least two thin film transistors (74) having Same pixel electrode (7
At least two thin film transistors (74) connected to 3)
Are arranged at right angles with one corner of the connected pixel electrode (73) interposed therebetween. 2. The same pixel electrode (73) according to claim 1.
At least two thin film transistors (74) connected to
Is arranged in parallel with the same short side of the pixel electrode (73) to be connected, the liquid crystal display panel.