JPH03166522A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To correct the dispersion in operating characteristics by providing plural small section parts positioned intermittently along the longitudinal direction of a long piece shape part in this part so that the length of the function part of a sintered body varistor element can be adjusted by cutting and separating the small section parts. CONSTITUTION:A metallic electrode 28 is formed to the long piece shape part in which the part to be connected to the sintered body varistor element 23 extends toward the junction of the sintered body varistor element 23 and a line electrode 21. The plural small section parts 28a positioned intermittently along the longitudinal direction of this long piece shape part are provided in this part. The long piece shape part is formed to a ladder shape. The length (d1 to d5) of the function part of the sintered body varistor element 23 is adjusted by cutting the small section parts 28a by laser fusion cutting, etc., and disconnecting the metallic electrode 28 from its front end part when there is a fluctuation in the varistor characteristics between the respective liquid crystal picture elements. The characteristics of the sintered body varistor element 23 are adjusted in this way, by which the dispersion in the operating characteristics of the liquid crystal display device is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a two-element liquid crystal display (LCD) using a sintered varistor element as a nonlinear element.

[Prior Art] At present, image display devices for, for example, liquid crystal televisions are broadly classified into simple matrix type and active matrix type.

In the simple matrix method, a plurality of liquid crystal pixels are arranged in a matrix and connected between two sets of band-shaped electrode groups (row electrode group and column electrode group) arranged at right angles. During this time, a predetermined voltage is applied by a drive circuit to operate the liquid crystal pixels. This method has the advantage of being able to realize a system at a low cost due to its simple structure, but because crosstalk occurs in each LCD pixel, the contrast of the image is low, and it cannot be used for displaying images on LCD TVs. there were.

On the other hand, in the active matrix method, a switch is provided for each liquid crystal pixel to maintain the voltage, and even if the liquid crystal display device is time-divisionally driven, the liquid crystal pixel can maintain the voltage at the time of selection. It is possible to increase the display capacity,
It has good image quality characteristics such as contrast, and can be used to display images on a liquid crystal television. However, the active matrix method has the disadvantage that the structure is complicated and the manufacturing cost is high.

For example, in a TFT type switch that uses a film-like field effect transistor as a switch, it is difficult to increase the product yield because five or more photomasks are used in the manufacturing process to stack five or more thin films.

Due to the above-mentioned circumstances, there is a desire to realize a liquid crystal display device that has good characteristics related to image quality such as contrast, has a simple structure, and is low in cost. Two-terminal element type liquid crystal display devices using varistor elements are attracting attention.

The two-terminal element type liquid crystal display device is an improvement on the simple matrix method, and as shown in FIG.
The sintered varistor element 3 and the liquid crystal pixel 4 are electrically connected in series between the sintered varistor element 3 and the liquid crystal pixel 4. This is what was used. In other words, in time-division driving using the simple matrix method, as shown in FIG. (=V90/
V 10= (V 10+ , a V )/V 1
o), the maximum number of scanning lines Nrnax allowed without causing crosstalk between each liquid crystal pixel is Nmax
= ((72+1)/γ2-1))2, and the smaller the value of γ, the larger the number of scanning lines, which is advantageous for liquid crystal television display. On the other hand, in the two-terminal element type, a voltage exceeding the threshold voltage v is applied to the liquid crystal pixel 3 by the sintered varistor element 4, and no sintered varistor element is provided. By providing a sintered body varistor element, the operating voltage of the liquid crystal pixel (see FIG. 11(a)) is increased by its threshold voltage Vv (see FIG. 11(a)).
b)). As a result, the value of γ is V90/V
10 to (VV+V90)/(VV+V10), the maximum number of scanning lines Nn+ax can be increased by decreasing the γ value, and a high-quality liquid crystal display can be realized.

5 to 7 show conventional two-terminal element type liquid crystal display devices.

As shown in the figure, a row electrode 11 and a pixel electrode 12 are provided on a lower glass substrate 10 at a predetermined distance d, and these row electrodes 11 and pixel electrodes 12 are connected by a sintered ZnO varistor element 13. It has been done. Then, attach the upper part of these to the liquid crystal 14.
Furthermore, column electrodes 15, color filters 16, and an upper glass substrate 17 are provided.

As shown in detail in FIG. 7, the sintered varistor element 13 is
Varistor grains 13a in which ZnO is coated with Mn and Co oxides
is sintered with a glass frit 13b, and a threshold voltage of about 3 μm can be obtained per varistor grain with a grain size of about 5 μm. Therefore, the distance d between the row electrode 11 and the pixel electrode 12
is set to 30 μm, one electrode 11 is connected via substantially six varistor grains 13a in series within this interval d.
and the pixel electrode 12 are connected, and a threshold voltage of 6×3V=18V is obtained between these electrodes 11 and 12.

[Problems to be Solved by the Invention] The two-terminal element type can realize a liquid crystal display device with a simple structure and low cost and good image quality, but the characteristics of the sintered varistor element 13 are limited by the varistor grains 13a. particle size,
Since the distance d between the row electrode l1 and the pixel electrode 12 changes due to minute errors, there is a problem in that the operating characteristics of the liquid crystal display device vary.

The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a liquid crystal display device that can adjust the characteristics of a sintered varistor element and correct variations in the operating characteristics of the liquid crystal display device. shall be.

[Means for Solving the Problems] A liquid crystal display device according to the present invention is a liquid crystal display device in which a sintered varistor element and a liquid crystal pixel are electrically connected in series between a row electrode and a column electrode. In this step, the sintered varistor element connected to the row electrode and the electrode of the liquid crystal pixel are connected by a conductive piece, and the part of the conductive piece connected to the sintered varistor element is connected to the sintered varistor element. It is formed into a long strip shape that extends toward the connecting portion with the row electrode, and a plurality of small cross-sectional portions are provided intermittently along the elongated direction in the long strip-shaped portion, and the small cross-sectional portions are cut and separated. This feature makes it possible to adjust the length of the functional portion of the sintered varistor element.

[Function] In the liquid crystal display device of the present invention, the length of the functional portion of the sintered varistor element is adjusted by cutting and separating the small cross-section portion of the conductor piece using laser cutting or the like. The characteristics of the liquid crystal display device are adjusted to correct variations in the operating characteristics of the liquid crystal display device.

When cutting and separating the conductor pieces, a small cross section is cut, so there is less risk of damaging the sintered varistor element and damaging its characteristics, and the small cross section can be used as a guide for adjustment. It can also happen.

[Example] A liquid crystal display device according to the present invention will be specifically described based on an example.

1 and 2 show a liquid crystal display device according to an embodiment of the present invention.

As shown in the figure, a pixel electrode 22 is provided on a lower glass substrate 20. , ZnO are provided at intervals, and the pixel electrode 22 and the sintered varistor element 23 are connected by a metal electrode 28 as a conductive piece. A row electrode 21 is formed on the sintered varistor element 23 at a distance di from the tip of the metal electrode 28. The other configurations are the same as the conventional example described above, and the upper part is connected to the liquid crystal 24.
Furthermore, column electrodes 25, color filters 26, and an upper glass substrate 27 are provided.

This sintered varistor element 23 has a composition similar to that shown in FIG. 7, and is formed on the lower glass substrate 20 in the following manner. Add 25% by weight of glass frit and 10% by weight of ethyl cellulose to barista grains with a particle size of approximately 5 μm,
Carbidol is used as a solvent to form an ink, which is screen printed on the lower glass substrate 20 on which the pixel electrodes 22 have been formed in advance, and then sintered. After sintering the sintered varistor element 23, a metal electrode 28 is formed into a predetermined shape by vapor deposition, sputtering, or the like. That is, in the metal electrode 28 of this embodiment, the portion connected to the sintered varistor element 23 is formed into a long piece shape extending toward the connection portion between the sintered varistor element 23 and the row electrode 21, and this length is A plurality of small cross-section portions 2 are located intermittently along the longitudinal direction of the piece-shaped portion.
8a is provided, and the long piece-shaped portion is formed into a ladder shape.

According to the above configuration, the varistor characteristics are tested with the row electrodes 21 and the metal electrodes 28 formed on the sintered varistor 23, and if there is variation in the varistor characteristics between each liquid crystal pixel, , the length (di
-d5), thereby adjusting the sintered body varistor element 23.
It is possible to correct variations in the operating characteristics of the liquid crystal display device by adjusting the characteristics of the liquid crystal display device. That is, when the small cross-section portions 28a are sequentially cut from the tip side of the metal electrode 28, the row electrode 2
The length of the sintered band varistor element 23 contributing to the connection between the varistor 1 and the metal electrode 28 increases sequentially from di to d5, and as a result, the threshold voltage vv increases sequentially. In addition, when cutting the metal electrode 28, a small cross-sectional area 28a having a small cross-sectional area is cut.
Since the sintered body varistor element 23 is cut, the cutting can be performed easily and quickly, and there is little risk of damaging the sintered varistor element 23 and impairing its characteristics. Further, since the plurality of small cross-section portions 28a are disposed intermittently, the work can be easily performed using these small cross-section portions 28a as a guide for adjustment.

FIGS. 3 and 4 each show another embodiment of the present invention.

The metal electrode 28 shown in FIG.
8 is formed into a comb shape with both teeth. These have one small cross-section portion 28a disposed intermittently in the longitudinal direction of the metal electrode 28, and are cut in comparison with the one shown in FIG. 1 in which there are two small cross-section portions 28a on the left and right sides. Work can be done easily.

In the above embodiments, a sintered varistor element made of ZnO is shown, but a sintered varistor element made of other known materials such as SiC may also be used.

[Effects] According to the liquid crystal display device of the present invention, since the elongated portion of the conductor piece is provided with a plurality of small cross-sectional portions located intermittently along the elongated direction, the small cross-sectional portions are cut and separated. This makes it possible to adjust the characteristics of the sintered body varistor element to correct variations in the operating characteristics of the liquid crystal display device, and to provide a liquid crystal display device with a simple structure, low cost, and excellent image quality.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along arrows 1 and 2 in FIG. 1, and FIG. 3 is a plan view of a liquid crystal display device according to another embodiment of the present invention. FIG. 4 is a plan view of a liquid crystal display device according to yet another embodiment of the present invention, FIG. 5 is a plan view of a conventional liquid crystal display device, and FIG. 6 is a plan view of a conventional liquid crystal display device. FIG. 7 is an enlarged view of the main parts in FIG. 6, FIG. 8 is a schematic configuration diagram of a two-terminal element type liquid crystal display device, and FIG. 9 is a diagram of a sintered varistor element. Voltage-current characteristic diagram, Figure 10 is a liquid crystal pixel operating characteristic diagram, Figure 11 (a)
(b) is an operational characteristic diagram of a liquid crystal pixel explaining the action of a sintered body varistor element. 21 is a row electrode, 22 is a pixel electrode, 23 is a sintered varistor element, 24 is a liquid crystal, 25 is a column electrode, 28 is a metal electrode (conductor piece), and 28a is a small cross section.

Claims (1)

[Claims] In a liquid crystal display device in which a sintered varistor element and a liquid crystal pixel are electrically connected in series between a row electrode and a column electrode, the sintered varistor element and the liquid crystal pixel electrode connected to the row electrode are connected by a conductor piece, and a portion of the conductor piece to be connected to the sintered varistor element is formed into a long piece shape extending toward the connection portion between the sintered varistor element and the row electrode, The length of the functional part of the sintered varistor element can be adjusted by providing a plurality of small cross-sectional parts intermittently located in the long strip-shaped part along its longitudinal direction, and cutting and separating the small cross-sectional parts. A liquid crystal display device characterized by: