KR960014650B1 - Liquid crystal display elements - Google Patents

Abstract

The device is for preventing the destruction of an electrode pattern due to the electrostatic electricity generated in the manufacturing process. The circuit prevents the break-down of a transparent conductor by distributing the electrostatic electricity on the entire liquid crystal cell uniformly.

Description

LCD

1 is a cross-sectional view of a conventional liquid crystal display device.

2 is a cross-sectional view of the liquid crystal display device of the present invention.

3 is an equivalent circuit diagram between adjacent pixels of the liquid crystal display device of the present invention.

* Explanation of symbols for main parts of the drawings

3,3 ': transparent conductive film 4,4': insulating film

9,9 ': Antistatic conductive film 5,5': Alignment film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which prevents breakage of an electrode pattern due to static electricity, which is likely to occur in a manufacturing process.

A cross-sectional view of a conventional liquid crystal display device is shown in FIG.

Parts indicated by reference numerals 1 and 1 'are upper polarizing plate and lower polarizing plate, respectively, 2,2' is a glass substrate, and 3,3 'is a transparent conductive film which forms ITO (In ₂ O ₃ ) on the glass substrate and selectively It forms by etching.

Reference numeral 4,4 'is an insulating film and SiO ₂ is a main component, and serves to prevent the penetration of metal ions from the glass substrates 2, 2' or the transparent conductive films 3, 3 '.

The portion denoted by reference numeral 5 is an alignment layer which is an organic film mainly composed of PI, and serves to arrange liquid crystal molecules uniformly, and 6 is a liquid crystal layer when voltage is applied to the transparent conductive film 3 and when no voltage is applied. The molecular arrangement of this liquid crystal layer is different.

The part indicated by reference numeral 7,7 'forms a closed curved surface together with the glass substrate 2 with a sealant, and serves to trap the liquid crystal, and 8,8' is made of glass fiber as a spacer. The upper glass substrate 2 and the lower glass substrate 2 'serve to maintain a constant gap.

Looking at the operation of the liquid crystal display device of the above structure, when the non-polarized light is incident from the upper glass substrate 2 direction to the lower glass substrate 2 direction, the light is linearly polarized by the upper polarizing plate 1, and the light is When the silver voltage is not applied to the upper and lower transparent conductive films 3 and 3 ', the light becomes linearly polarized by the twisted liquid crystal molecular layer 6, and when it passes through the liquid crystal layer, it becomes an elliptical polarization and a part of its components is the lower polarizing plate. Selective transmission is performed by 1 '.

When the voltage is applied to the upper and lower transparent conductive films 3 and 3 'at a voltage higher than or equal to a specific voltage, since the molecular arrangement of the liquid crystal layer 6 is nematic, the linear polarization plate 1 The polarized light is not affected while passing through the liquid crystal layer 6, and thus becomes linearly polarized light and passes through the lower polarizing plate 1 ′.

The liquid crystal display device is a light-receiving device using the fact that the polarization state of the two light emitted through the liquid crystal layer when the voltage is applied and when not applied as described above is different.

Looking at the manufacturing method of the conventional liquid crystal display device as follows.

The glass substrate 2 coated with the transparent conductive film 3 is washed and dried to remove moisture on the glass substrate. Then, the photosensitive resin is coated on the glass substrate 2 and the photosensitive resin is selectively irradiated with light to form a transparent conductive film. By etching, a desired transparent conductive film pattern 3 is formed.

The upper and lower transparent conductive films 3 and 3 'of FIG. 1 have a matrix form shifted by 90 degrees from each other. When the transparent conductive film pattern 3 is formed, a solution containing SiO ₂ as the main solute is coated by using a roll coating method, followed by drying to evaporate the solvent, thereby making the SiO ₂ film 4 approximately 500 kPa. Form to thickness. Subsequently, the PI film 5 is printed on the SiO ₂ film 4 again using a roll coating method. At this time, the spacer 8 is mixed with the PI film and printed. The PI film 5 is then rubbed with a rubbing cloth to form mechanical scratches on the PI film. Subsequently, the sealing compound 7 is screen printed, and the upper and lower glass substrates are pressure-cured to form two liquid crystal cells by attaching two glass substrates. In this case, since a plurality of liquid crystal cells are formed on the glass substrate, the glass substrate is scribed using silicon carbide or a diamond cutter to be divided into respective liquid crystal cells, and then cut by applying mechanical impact. Subsequently, the unit liquid crystal cell and the liquid crystal are put in a vacuum chamber, and the air is extracted, ultrasonic waves are applied to a container containing liquid crystal to remove moisture or bubbles contained in the liquid crystal. When the chamber is in a vacuum state, the liquid crystal is sucked into the liquid crystal cell due to the difference between the air pressure in the liquid crystal cell and the air pressure in the chamber and the capillary phenomenon.

When the liquid crystal injection is completed as described above, the injection hole is sealed with a photocurable resin to prevent contact between the liquid crystal, air, and moisture contained in the air. Subsequently, the liquid crystal cell is washed with a freon for about 20 seconds so that the polarizer and the glass substrate are adhered to each other by removing a human hand or an organic substance from the liquid crystal cell, and then attach the polarizers 1, 1 '.

In the above-described conventional liquid crystal display device manufacturing, the rubbing process is performed by friction between the rubbing cloth and the PI film, which is an alignment film, whereby the rubbing cloth is charged with positive charge and the PI film is negatively charged by the electrostatic coefficient of the two materials. Will be taken.

The negative charge of the PI film 5 is diffused through the insulating film 4 to the transparent conductive film 3 by the diffusion action. The negative charges diffused into the transparent conductive film 3 are distributed in the angular portions of the transparent conductive film, and the charges collected in the angular portions induce the opposite charges to the adjacent transparent conductive films.

This induced charge instantaneously generates a constant voltage of thousands of V, causing the transparent conductive film to break (break-down), resulting in a sharp rise in resistance (from 10 ¹² Ω / ㎠ to 10 ⁴ to 10 ⁵ Ω / ㎠), resulting in crosstalk. The problem of lowering the picture quality occurs as a cause of cross-talk.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and its purpose is to distribute the electrostatic charges generated during the rubbing process of the liquid crystal display device manufacturing process evenly to the entire liquid crystal cell to prevent deterioration of the transparent conductive film.

In order to achieve the above object, the liquid crystal display device of the present disclosure is characterized in that an antistatic conductive film is formed between the alignment film and the transparent conductive film.

The antistatic conductive film is formed of SixTiyO ₂ (1-xy).

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

2 is a cross-sectional view of a liquid crystal display device according to the present invention. In Fig. 2, the same parts as those in Fig. 1 are denoted by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 2, the liquid crystal display of the present invention has a structure in which an antistatic conductive film 9, 9 'is formed between the PI film 5 and the insulating film 4, which are alignment films.

The conductive films 9 and 9 'uniformly distribute the electrostatic charge generated between the rubbing cloth and the PI film 4 as the alignment film in the rubbing process to serve to suppress the generation of inductive charges.

3 is a registration circuit diagram between adjacent pixels (x, y) of the liquid crystal display device according to the present invention. Vx is the voltage applied to the x pixels, Vy is the voltage applied to the y pixels and the R _{conductive film} is the resistance of the conductive film. If the capacitance of the pixel x, y is C, in order to apply the applied voltage Vx, Vy to the pixel x, y independently

The condition of must be satisfied.

In the above formula, f represents a driving frequency. Usually C 0.5pF, f = 10KH _Z, so the impedance of liquid crystal ) Is about 10 ⁷ Ω / cm 2. Therefore, when the sheet resistance (R _{conductive film} ) of the conductive film of FIG. 3 is about 10 ⁹ Ω / cm 2 or more, Vx and Vy are independently applied to the pixels x and y.

On the other hand, the conventional insulating film has a sheet resistance of about 10 ¹³ Ω / ㎠, but because it does not effectively suppress the generation of inductive charges for static electricity, the purpose of the conflict between the applied voltage problem and the static electricity generation problem for each pixel In order to achieve effectively, the sheet resistance of the conductive film is appropriately 10 ⁹ Ω / cm 2 to 10 ¹¹ Ω / cm 2.

SixTiyO _{2 (1-xy)} is used as the conductive film, which is not always composed of a constant molecular formula, but when crystallized in an amorphous or gel state, Si and Ti are mixed without being sintered in a predetermined amount. Since it is determined by the ratio, it is expressed by the above molecular formula. The larger the amount of Si (95% or more), the sheet resistance is about 10 ⁹ Ω / cm 2. As the antistatic conductive film of the present invention, it is preferable to use SixTiyO _{2 (1-xy)} having a Si-to-Si mixing ratio of 20 times or more. desirable.

As described above, the present invention provides a liquid crystal display device having high yield because an antistatic conductive film of SixTiyO _{2 (1-xy)} is formed between the alignment layer and the insulating layer to prevent breakage of the transparent conductive layer due to the electrostatic charge generated during rubbing. You can get it.

Claims (3)

And a conductive film having a sheet resistance of 10 ⁹ Ω / cm 2 to 10 ¹¹ Ω / cm 2 between the transparent conductive film and the alignment film. The liquid crystal display device of claim 1, wherein the conductive film is formed of SixTiyO _{2 (1-xy)} . The liquid crystal display device according to claim 2, wherein a mixing ratio of Si to Six TiyO _{2 (1-xy)} to Ti is 20 times or more.