JPS5888787A - Liquid crystal display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display bag f6 in which nonlinear elements are arranged in a matrix. More specifically, the method for measuring the electrical characteristics of the nonlinear element and the possibility of measuring the electrical characteristics relate to the structure of a liquid crystal display device.

The liquid crystal display device according to the present invention is a large capacity dot matrix liquid crystal display device. When each dot (liquid crystal display pixel) is an electrode at the intersection of scanning lines and data lines arranged in an IJ box shape, the effective value per cycle of the voltage at the intersection is the threshold of the liquid crystal. (If it is higher than rU, the light will turn on,
If the effective value is low, the light will not turn on.

On the other hand, as the number of scanning lines increases, the selection time at the intersection becomes shorter, and if the driving voltage is constant, it becomes difficult to obtain an effective value higher than Vsat for lighting the liquid crystal.

If the drive voltage is then increased, the effective values of the unselected intersections will also increase. In order to suppress the occurrence of 70 strokes due to the poor threshold characteristics of the liquid crystal and obtain a contrast that can withstand practical use, the limit is up to 1/16th of a day.

Conventionally, as a method to increase the duty, a metal-insulator-metal element (hereinafter referred to as M element), which is a nonlinear element, is formed between the scanning line and the data line with a liquid crystal layer interposed between the scanning line and the data line. and the scanning line was connected. If the M element has properties close to diode characteristics, the selection signal from the scanning line can be stored in the MIM element during the selection period to compensate for the drop in effective value during the non-selection period. I can do it. Although it depends on the transmittance and resistivity of the liquid crystal, it is easy to obtain several hundred data.

An example of a pattern of a conventional liquid crystal display device is shown in FIG.

The pattern is formed on a glass substrate.

The timing line 101 in the figure is used as one electrode.
An oxide film is formed between the metal thin film 102 and an M element. Reference numeral 103 is a transparent metal connected to the metal thin film, and is a liquid crystal drive electrode that applies a voltage to the liquid crystal to drive it.

This figure only shows a part of the pattern, and the actual pattern consists of several hundred timing lines. Furthermore, hundreds of liquid crystal drive electrodes connected to the timing line are formed per timing line, and the number of pixels in the entire pattern is tens of thousands.

It is desirable for each pixel to be of good quality, but in reality, defects such as disconnections in timing lines, defects in M process M elements, and defective patterns in liquid crystal drive electrodes occur due to various problems in the manufacturing process. do.

A break in a timing line can be checked by touching both ends with a needle and measuring the resistance of the timing line. However, if a defect occurs in a pixel, it is impossible to discover the presence or absence of the defect and the location of the defect unless the operation of the liquid crystal is confirmed when the pixel is mounted and actually driven.

On the other hand, a defect in an M element is strictly speaking a defect in the element characteristics, but ultimately it depends on whether or not the liquid crystal can be sufficiently driven in a selected duty time of several hundred. Items that can maintain this are good and others are defective.

As described above, defects in pixels cannot be investigated unless they are mounted, and in order to analyze defects, it is necessary to destroy the mounted liquid crystal display device, which is extremely difficult.

Further, defects cannot be corrected, and there are drawbacks such as a decrease in yield and an increase in costs due to the mounting process, and improvements are desired.

The present invention eliminates the above-mentioned drawbacks, and its purpose is to provide a structure of a liquid crystal display device and a method for measuring the electrical characteristics, which allows the electrical characteristics of pixels of the liquid crystal display device to be measured before mounting.

The structure of the liquid crystal display device according to the present invention will be described in detail below.

Figures 2 and 3 are examples, and in the figures 201 to 203 and 3.
01 to 303 are the same as the description of the conventional pattern, and will therefore be omitted. Reference numerals 204 and 304 indicate a board for connecting the liquid crystal drive electrodes for each row, and 305 indicates a terminal for electrically connecting the liquid crystal drive electrodes to the outside. The shaded area is the same thin film as the electrodynamic frame on the liquid crystal θ, and the electrodes are formed at the same time.

The liquid crystal drive electrode is formed using any one of the above three types of thin films: an indium oxide thin film, a thin film formed by forming a gold thin film with the same pattern on the indium oxide thin film, and a gold thin film.

Next, a method of measuring pixels using the equivalent circuits shown in FIGS. 2 and 3 and the above structure will be explained.

In Fig. 4, 401 is a timing line, and 402 is a timing line.
403 is a liquid crystal drive electrode line, 404 and 405 are terminals for electrically connecting the timing line and liquid crystal drive line to the outside, 406 is a resist register, and 407 is a MOS transistor. This is a transmission gate (hereinafter referred to as an analog switch).

Connection between the liquid crystal drive device and an external shift register is made by diagonal contact using a probe card and pressure contact using anisotropic conductive rubber and heat sealing.

Select any analog switch with the soft register,
Select the timing line and liquid crystal drive electrode line.

One side of the analog switch is connected for each line, and the timing line side is connected to the VT liquid crystal drive electrode line side.
Set to 0. An impedance meter and a cavanter meter are connected between VT and 0, and the 2-2 characteristics of the M element and the capacitance of the element are measured at the intersection of each line selected by the soft register.

In this case, since the intersection of the liquid crystal drive electrode line and the timing line itself also has a kind of M/M structure, it is necessary to correct the measurement data.

Measurement of the (1)-mechanical characteristics at the intersection shows almost the same characteristics when the liquid crystal driving electrode line side is the negative electrode and the timing side is the positive electrode, as shown in FIG. 5(a). (
+, ) are equivalent circuits, which are connected in parallel with the equivalent circuits of MT and M elements. For this reason, the ■-■ characteristics of the M element are measured with the liquid crystal drive electrode line side as the positive electrode and the timing line side as the negative electrode, taking into account the current value flowing due to the M element structure at the intersection point itself. If the measurement data is corrected and the opposite measurement is performed, no correction is required. Measurement of touts requires correction regardless of polarity.

It is necessary to measure the data of the V-2 characteristics and capacity due to the M/M structure of the intersection itself in advance and understand the variations in the data.

Once a pixel defect is found through measurement in this manner, the address of the pixel can be found by counting how many steps the shift register has shifted.

After completing the full11 period, in order to mount the liquid crystal drive device,
The pattern other than the conductor connecting between the liquid crystal drive electrodes is masked with a resist or the like and etched to restore the pattern to the conventional liquid crystal drive device pattern.

According to the present invention, it is possible to confirm the presence or absence of pixel defects in the liquid crystal drive device before mounting, and it becomes possible to correct and analyze defective addresses, improving yields and feeding back analysis results to the next process to establish manufacturing processes. can be achieved.

[Brief explanation of drawings]

FIG. 1 is a partial schematic diagram of a pattern constituting a conventional liquid crystal driving device. FIGS. 2 and 6 are partial schematic diagrams of patterns of embodiments of the present invention. FIG. 4 is a schematic diagram of an equivalent circuit of an M-processor M-element according to an embodiment of the present invention and peripheral circuits connected to the outside. FIG. 5 (α) represents the 1-2 characteristic at the intersection of the timing line and the liquid crystal drive electrode line, and (1,) represents the equivalent circuit at the intersection. Above (9) 601

Claims (1)

[Claims] 1. A nonlinear element with a metal-insulator-metal structure
In a liquid crystal display device in which the nonlinear elements are arranged in an IJ box shape, one metal of the nonlinear element is connected to each column wiring, and the other metal is connected to a liquid crystal drive electrode, the liquid crystal drive electrode is connected to each row. A liquid crystal display device characterized by all being connected in series. 2. Measuring the characteristics of each nonlinear element by making an electrical connection between the column wiring to which one metal of the nonlinear element is connected and the outside, and also making an electrical connection between each row of the liquid crystal drive electrodes and the outside. A liquid crystal display device according to claim 1, characterized in that: 3. The liquid crystal display device according to claim 1, wherein after the measurement of the characteristics is completed, the metal connecting the liquid crystal drive electrode is etched.