JPH0313920A - Electrostatic breakdown preventive electrode structure of liquid crystal display element - Google Patents

Abstract

PURPOSE:To prevent a nonlinear resistance element from breaking down by providing a non-display area consisting of picture elements outside a display area which is used as picture elements by the input terminal of one picture element formation side substrate. CONSTITUTION:In the range of a picture element group 7, several picture elements are further arranged between the input terminal part and the picture element group 7 of the display area. The capacity of those picture elements which are provided nearly lowers the applied voltage of static electricity, so the applied voltage of static electricity applied to the nonlinear resistance element 4 of the display area picture element part can be suppressed low and the nonlinear resistance element 4 is therefore prevented from breaking owing to an excessive voltage generated by static electricity, etc., during packaging in a manufacture process. Further, picture element formation for electrostatic breakdown prevention is possible in a conventional manufacture process under conventional manufacture conditions only by changing a pattern mask, so the manufacture cost does not increase and the manufacture yield does not decrease.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an active matrix liquid crystal display device in which a nonlinear element is provided for each pixel.

[Summary of the invention]

In an active matrix liquid crystal display device using a non-linear resistance element, the present invention is capable of destroying the non-linear resistance element from an excessive input signal applied from the outside or a voltage caused by static electricity by forming a pixel with a capacitance between opposing electrodes. It is designed to prevent this.

[Conventional technology]

As an example of a conventional liquid crystal display element, the equivalent circuit of an active matrix liquid crystal display element using a nonlinear resistance element is shown in the second example.
Figure (shown in al.

Figure 2 (al) 11 is a row electrode, 12 is a column electrode, and pixels 15 are arranged for the required number of pixels. At the intersection of the row electrode and column electrode, a liquid crystal 13 and a nonlinear resistance element 14 are connected in series. is formed.

Fig. 2(a) shows a plan view of an active matrix liquid crystal display element using a conventional nonlinear resistance element.

FIG. 2 fc) is a sectional view of an active matrix liquid crystal display element using a conventional nonlinear resistance element.

A nonlinear resistance ll117 is provided on the film of the pixel electrode 16, and a row electrode 19 is further provided on the film 17 to form a nonlinear resistance element.

A liquid crystal 21 is sealed and held between glass substrates 20 and 20.

FIG. 4 shows the current-voltage characteristics between the pixel electrode 16 and the row electrode 19 of this element.

In FIG. 4, the vertical axis is current, and the horizontal axis is voltage, where voltage is the logarithm of the current flowing through the element. From this diagram, it can be seen that there is a steep current-voltage characteristic. Furthermore, due to the structure of the liquid crystal display element, the column electrodes are floating from the ground potential (because they are not grounded due to the electrode structure).

For this reason, if static electricity of several kilovolts is applied to either the row electrode or column electrode terminal, this voltage will be applied directly to the nonlinear resistance element, exceeding the electrostatic withstand voltage of the element and damaging the nonlinear resistance element. It will be destroyed (electrostatic damage).

Until now, manufacturing yield and product reliability of liquid crystal display elements using nonlinear resistance elements have been poor due to such electrostatic damage.

[Problems to be Solved by the Invention] In the conventional technology, pixel defects due to abnormalities in nonlinear resistance elements caused by static electricity occur relatively frequently, which promotes a decrease in yield and an increase in costs.

Failures of nonlinear resistance elements due to static electricity occur over a wide range of situations, from ``during the product manufacturing process'' to ``after the product is completed,'' and it is extremely difficult to take measures to prevent failures caused by static electricity.

Therefore, the present invention provides an active matrix liquid crystal display element using a nonlinear resistance element that is relatively easy to prevent destruction of the nonlinear resistance element due to static electricity, and has high yield and reliability without increasing the product manufacturing process. is intended to do.

[Means to solve the problem]

The above-mentioned problem is solved by providing at least one pixel outside the display area used as a pixel at the input terminal of at least one pixel electrode forming side substrate.

[Effect]

The majority of pixel defects caused by static electricity tend to occur within a few pixels from the input terminal side. A number of pixels corresponding to several pixels are provided in .

This newly installed pixel capacitance lowers the voltage applied to static electricity, which makes it possible to keep the voltage applied to static electricity applied to the nonlinear resistance elements in the pixel area of the display area low, thereby preventing the destruction of these nonlinear resistance elements. I can do it.

〔Example〕

As Example +11 of the present invention, an equivalent circuit diagram of an active matrix liquid crystal display element using a nonlinear resistance element is shown in the first example.
Shown in Figure 1al.

In FIG. 1 (al), 1 is a row electrode, 2 is a column electrode, and pixels 5 are arranged as many as the required number of pixels.

A liquid crystal 3 and a nonlinear resistance element 4 are placed at the intersection of the row electrode and column electrode.
are formed in series.

The structure up to this point is the same as the conventional technology, but there are 7
As shown in the area surrounded by , several more pixels were arranged between the input terminal section and the pixel group 6 in the display area.

Since the structure of this newly arranged pixel group 7 is similar to that of the conventional technology, it can be manufactured using the conventional manufacturing process and manufacturing process conditions by changing only the pattern mask. 1st
8 in the figure (FIG. 1 (1) in which bl shows a plan view of the substrate in the embodiment of the present invention) is!・The T.0 transparent electrode becomes the pixel electrode. 9 is a nonlinear resistance element, 1 is a row electrode, and 2 is a column electrode on the opposing substrate side. A number of pixels identical to the pixels formed in the display area are formed between the input terminal portion 1a and the display area as many as possible to suppress the applied voltage of static electricity.

An equivalent circuit diagram of another embodiment of the present invention is shown in FIG.

This embodiment is different from the above-described embodiments in that the input terminal section 1a
The shape of the pixel group provided between the pixel groups of the display area that causes the display effect is different. As shown in the figure, the pixels are formed to be at least one times larger than the pixels formed in the display area, and accordingly, the nonlinear resistance element can be made larger by the size of the pixels. In this way, the size of the pixels provided to prevent electrostatic damage is varied, and after the module is completed, the number of pixels is reduced so as not to adversely affect the appearance of the display.

〔Effect of the invention〕

In the present invention, pixels are formed in an active matrix liquid crystal display element using a nonlinear resistance element to prevent damage caused by static electricity, thereby preventing damage caused by excessive voltage caused by static electricity, etc. of the nonlinear resistance element that occurs during the manufacturing process and mounting. It can be prevented. In addition, pixel formation to prevent electrostatic damage can be manufactured using the conventional manufacturing process and manufacturing conditions by changing only the pattern mask, so there is no increase in the manufacturing process and the manufacturing cost does not increase. , and the manufacturing yield does not decrease.

FIG. 3 is a cross-sectional view of one pixel of a liquid crystal display element, FIG. 3 is a plan view of another embodiment of the present invention, and FIG. 4 is a graph showing current-voltage characteristics of a nonlinear resistance element.

1... Row electrode 3...LCD 6...Display area 2...Column electrode 4...Nonlinear resistance element 7... Hidden area that's all

Claims (1)

[Claims] On one substrate, pixels consisting of pixel electrodes and nonlinear resistance elements are formed in a matrix as row electrodes or column electrodes, and on the other substrate, column electrodes or row electrodes are formed. In a liquid crystal display element in which liquid crystal is sealed between formed substrates, a non-display area consisting of pixels is provided outside the display area used as pixels at the input terminal of at least one pixel forming side substrate. LCD display element.