JPH0497137A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To reduce capacity formed between a driving electrode and a counter electrode and reduce the current consumption by removing the part of the wiring pattern of the counter electrode which overlaps with the driving electrode so that part of it is left. CONSTITUTION:Plural picture element electrodes 2 are formed on a substrate 1 by depositing, for example, I.T.O., etc., by sputtering and etching it. Then a nonlinear resistance film 4 and the driving electrode 3 are deposited successively in this order and etched continuously in a single mask process. The counter electrode 5 is also formed by depositing I.T.O., etc., by sputtering and etching it selectively. At this time, part 5a of the pattern of the counter electrode 5 consisting of a transparent conductive film facing the driving electrode 3 is removed. Consequently, the parasitic capacity between the driving electrode 3 and counter electrode 5 decreases and the power consumption of a liquid crystal panel is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display panel for a measuring instrument, an image display device for a personal computer, a liquid crystal display device for a liquid crystal television, and the like.

[Summary of the invention]

The present invention provides a liquid crystal display device using a two-terminal element in which a nonlinear resistance film is provided between a pixel electrode and a drive electrode, in which a portion of the transparent electrode on a transparent substrate facing the drive electrode is covered. The purpose is to reduce the parasitic capacitance of the liquid crystal panel and reduce current consumption.

[Conventional technology]

2. Description of the Related Art Liquid crystal display devices have advantages over other display devices as small, lightweight, thin, and low power consumption display devices, and have been put into practical use in recent years. In order to increase the amount of information displayed on liquid crystal display devices, we are using three-terminal active matrix liquid crystal display devices such as thin film transistors, ZnO varistors, and so-called MTM type non-shape linear resistor elements consisting of metal-insulating film metal structures. Two-terminal active matrix liquid crystal display devices such as nonlinear resistance elements using silicon nitride films, oxide films, and the like are being researched.

Compared to three-terminal devices, one-terminal devices have features such as a smaller number of formed films and relatively rough patterning accuracy, and can be applied to low-cost, large-area display devices.

FIG. 3 is an X-Y matrix panel circuit diagram of a two-terminal active matrix liquid crystal display device using nonlinear resistance elements. Usually about 100 to 1000 row liquid crystal drive electrodes 31 and column liquid crystal drive electrodes 32 are formed on each of the substrate and the counter substrate. A liquid crystal 33 and a nonlinear resistance element 3 are placed at the X-Y intersection.
4 is formed. Figure 2 shows Si as a nonlinear resistance element.
FIG. 2 is a front view and a cross-sectional view of a two-terminal device using a rich silicon nitride film or the like.

After selectively forming a pixel electrode 2 (1, T, ○) on one transparent substrate, a nonlinear resistance film 4 (nitride silicon) is formed.
and a drive electrode 3 (Cr) (corresponding to the row liquid crystal drive electrode 31 in FIG. 3) are deposited and each is selectively etched.

On the other substrate, a counter electrode 5 (corresponding to the column liquid crystal drive electrode 32 in FIG. 3) made of a transparent conductive film is formed.

Driving of such a liquid crystal display device is performed as follows.

A large number of row electrodes 31 in FIG. 3 are selected line-sequentially from the top one by one, and data is written using the column electrodes 32 within the selection period. In order to display with sufficient contrast at this time, the effective voltage applied to the liquid crystal at the selected point must be greater than the saturation voltage of the liquid crystal, and the effective voltage applied to the liquid crystal at non-selected points must be higher than the saturation voltage of the liquid crystal. It needs to be smaller than the threshold voltage. When a nonlinear resistance film is used, the resistance of the nonlinear resistance film 24 becomes low at the selection point during writing (when high voltage is applied), and charges are easily injected into the liquid crystal 33.
During the holding period (when low voltage is applied), the resistance of the nonlinear resistance film 24 becomes high, and the charges injected into the liquid crystal 33 are easily held. In this way, the effective voltage applied to the liquid crystal 33 can be kept high. Furthermore, when not selected, the resistance of the nonlinear resistance film 24 does not decrease so much during writing, and not much charge is injected into the liquid crystal 33. Therefore, the effective voltage applied to the liquid crystal 33 can be kept relatively small, and high contrast can be maintained even if the number of divisions is considerably large.

In the nonlinear resistance element, the composition and structure of the nonlinear resistance film are determined so that the nonlinear resistance film has a desired resistance value during each of the writing period and the holding period. In addition, in order to obtain a sufficient drive margin when displaying with such a liquid crystal display device, it is necessary to increase the capacitance CL of the liquid crystal section in each pixel.
It is also necessary to make the ratio between C and the capacitance CI of the nonlinear resistance element section sufficiently large. (At least CLC/CI≧5) [Problem to be solved by the invention] In a simple matrix panel, the optimum bias voltage (+1) is determined by the number of divisions, but in a panel using two-terminal elements, the The characteristics determine the bias, which is usually larger than that of a simple matrix panel. Therefore, the voltage applied to the liquid crystal panel increases when it is not selected, increasing current consumption.

Furthermore, considering each pixel, the pattern on the two-terminal element side is about 10% driving electrodes, 90% pixel electrodes, and a capacitor with liquid crystal sandwiched between them and the counter electrode. When not selected, a bias voltage is applied to the drive electrode, and a bias voltage divided by capacitance ratio (CLC/CI = 10) is applied to the pixel electrode, and the current flowing at this time is 2πfCV (A), and the voltage between the drive electrode and the pixel electrode is Then, the capacity is 1=9 and the voltage is 10:
1, so it is consumed at a ratio of approximately 1:1.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention adopts a structure in which a part of the wiring pattern of the counter electrode is left behind, and a part of the wiring pattern overlapping with the driving electrode is removed.

[For production]

With the above structure, the capacitance formed between the driving electrode and the counter electrode is reduced, thereby reducing current consumption.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1st
The figure shows an embodiment of the present invention. In FIG. 1, a plurality of pixel electrodes 2 are formed on a substrate l. This is for example l T, 0. It can be formed by depositing such as by sputtering method or the like and selectively etching it. Next, a nonlinear resistive film 4 (for example, Si-rich 5iN
x) and the driving electrode 3 (for example, Cr) are successively deposited in this order and successively etched in - mask steps. Further, the counter electrode 5 is also 1. It can be formed by depositing T, O, etc. by sputtering or the like and selectively etching it. At this time, part 5 of the pattern of the counter electrode 5 made of a transparent conductive film facing the drive electrode 3
By removing the letter a, the parasitic capacitance between the driving electrode 3 and the counter electrode 5 is reduced. In the case of FIG. 1, both ends of the line are left and the central part is removed, but the same applies if one side is left and removed.

〔Effect of the invention〕

As explained above, according to the present invention, the current consumption of the liquid crystal panel can be reduced by about 40% by simply changing the shape of the mask without increasing the number of steps. Also, if you remove the center part while leaving both ends of the line, mask scratches,
The incidence of patterning defects due to dust etc. is also the same as that of conventional pixel patterns.

FIG. 3 is an X-Y matrix panel circuit diagram of a two-terminal active matrix liquid crystal display device using nonlinear resistance elements.

１　・・ 2・・・ ３　・・ ４　・・ 5　・・ 6 ・・ 33・・ 34・・ substrate pixel electrode Drive electrode nonlinear resistive film Counter electrode liquid crystal Row liquid crystal drive electrode Column liquid crystal drive electrode liquid crystal nonlinear resistance element

[Brief explanation of drawings]

Fig. 1 (δ1. (bl) is a plane and I-I sectional view showing the embodiment of the present invention, and Fig. 2 (181. fb) is a plane and nn sectional view showing the conventional pixel pattern, respectively. People Seiko Electronics Industries Co., Ltd.

Claims (1)

[Claims] In a liquid crystal display device that has a plurality of pixel electrodes on a transparent substrate and uses a two-terminal element consisting of a nonlinear resistive film, a driving electrode, etc., the transparent electrode is on a counter substrate that faces the substrate on which the driving electrode is formed. The liquid crystal display device is characterized in that a portion of the portion facing the driving electrode is covered.