JP2000284319A - Method for manufacturing active matrix type liquid crystal display element and display element thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an active matrix type liquid crystal display element which realizes high quality by suppressing a decrease in display quality due to the influence of impurity ions in a lateral electric field mode liquid crystal display element, and to provide the display element. . A liquid crystal is sandwiched between two substrates and a signal electrode, a scanning electrode and a pixel electrode are arranged on an array substrate, and an electric field parallel to the substrates is generated. In an active matrix type liquid crystal display device in which the arrangement causes the arrangement of liquid crystal molecules defined by the alignment layers 12 arranged on the substrates 1 and 7 to be changed, at least two combs are formed on the light shielding layer 9 arranged on the counter substrate 7. Electrode wiring 10,
11 are arranged in such a manner that the liquid crystal 13 is sandwiched between the substrates 1 and 7, and then an electric field is applied between the two comb-shaped electrode wirings 10 and 11 so that the impurity ions are disposed on the opposing substrate 7.
Take it on 0,11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used for a flat display such as an AV device, a personal computer (hereinafter, referred to as a personal computer), a word processor (hereinafter, referred to as a word processor), and more particularly, the display characteristics depend on the viewing angle. The present invention relates to a method of manufacturing an in-plane switching mode active matrix liquid crystal display element having a low resistance and a display element thereof.

[0002]

2. Description of the Related Art Liquid crystal display devices have been applied to liquid crystal televisions, personal computers, word processors, etc., and have recently been widely used as OA displays and projection TVs, and their display quality has been improving year by year.

In particular, an active matrix type liquid crystal display device using a thin film transistor (TFT) as a switching element has a great feature that a high contrast is maintained even when a large-capacity display is performed. It is being developed and commercialized as a favorite for large and large-capacity full-color displays for laptop and notebook computers, as well as for engineering workstations.

In such a display element of an active matrix type liquid crystal display device, there is a TN (Twisted Nematic) type as a widely used liquid crystal display mode. In the TN mode, a panel having a structure in which liquid crystal molecules are twisted by 90 ° between electrode substrates sandwiching a liquid crystal layer is sandwiched between two polarizing plates. When a voltage is applied between the electrode substrates, the liquid crystal molecules try to align in the direction of the electric field while unwinding the twisted structure, and the polarization state of the light passing through the panel changes depending on the arrangement state of the molecules, and the light transmittance is reduced. This is because it is modulated.

[0005] However, even in the same molecular arrangement state, the polarization state of transmitted light changes depending on the incident direction of light incident on the liquid crystal panel, so that the light transmittance differs according to the incident direction. That is, the characteristics of the liquid crystal panel have a viewing angle dependency. This viewing angle characteristic causes a luminance inversion phenomenon when the viewpoint is inclined obliquely to the main viewing angle direction (the major axis direction of the liquid crystal molecules in the intermediate layer of the liquid crystal layer). In other words, this phenomenon means that the display luminance at a certain voltage becomes brighter than the luminance at a lower voltage. In particular, the luminance reversal phenomenon when a high voltage is applied for black display is caused by the image quality of the liquid crystal panel. This is an important issue.

In order to solve this problem, instead of applying an electric field in a direction perpendicular to the substrate as in a TN type liquid crystal display system, a method of applying an electric field to the liquid crystal in a direction substantially parallel to the substrate (horizontal direction). Electric field type).
No. 1907 and JP-A-6-160878. A general horizontal electric field type liquid crystal display element has a structure in which an electrode substrate in which comb-shaped pixel electrodes and a common electrode are engaged and a panel in which liquid crystal is interposed between opposing substrates are sandwiched between two polarizing plates. Here, by applying a voltage between the pixel electrode and the common electrode, the molecular arrangement of the liquid crystal between the electrodes is changed planarly, and the light transmittance is modulated to display an image.
In the lateral electric field method, since the arrangement change of the liquid crystal molecules changes in parallel with the electrode substrate, a high-quality liquid crystal display device having little viewing angle dependence of light modulation can be obtained.

A general TN type and lateral electric field type manufacturing method uses a rubbing method in which the surface of an alignment layer of polyimide or the like formed on the substrate is rubbed using a resin fiber cloth. Is applied, and a bead material for controlling the thickness between the substrates is dispersed. Then, the counter substrate subjected to the rubbing treatment is bonded to the substrate coated with the sealing material, and the sealing material is cured. Then, a liquid crystal material is sandwiched between the substrates by a vacuum injection method to complete a liquid crystal display element.

[0008]

However, TN
In any of the liquid crystal display devices of the liquid crystal display type and the horizontal electric field type, the presence of the impurity ions causes an apparent change in the electric field applied to the display electrode for display, thereby deteriorating the display quality such as a decrease in contrast. In addition, impurity ions are unevenly distributed due to the driving electric field, and display defects such as display unevenness, afterimage, and burn-in phenomenon are caused. Examples of the impurity ions include impurity ions contained in the liquid crystal interposed in the element and impurity ions eluted into the liquid crystal from impurities mixed in the element during the manufacturing process. Therefore, impurity ions are reduced by using high-purity liquid crystal materials, advanced cleaning of liquid crystal injection jigs, measures against foreign substances, and the use of highly reliable sealing materials. However, this raises costs and reduces productivity. become.

The present invention relates to a method of manufacturing a high-quality active matrix type liquid crystal display element in which a display quality is not degraded due to impurity ions found in the above-mentioned conventional example and a display thereof in a horizontal electric field mode having a comb-shaped electrode on a substrate. It is intended to provide an element.

[0010]

In order to achieve the above object, the present invention provides an electrode substrate having signal wiring, scanning wiring, and pixel electrodes formed on a surface thereof, and an opposing substrate having a light shielding layer formed on the surface thereof. An active matrix type liquid crystal display device in which liquid crystal is sandwiched via an alignment layer to generate an electric field parallel to each substrate, thereby changing the arrangement of liquid crystal molecules defined by the alignment layer disposed on each substrate. In the manufacturing method, at least two comb-shaped electrode wirings are arranged so as to bite at a portion of the light-shielding layer opposite to the signal wirings or the scanning wirings, and after the liquid crystal is sandwiched between substrates, the two comb-shaped electrode wirings are formed. A step of applying an electric current to the wiring to generate an electric field between the comb-shaped electrode wirings.

Further, according to the present invention, a liquid crystal is sandwiched between an electrode substrate having signal wiring, scanning wiring and pixel electrodes formed on the surface thereof and an opposing substrate having a light shielding layer formed on the surface thereof, with an alignment layer interposed therebetween.
In an active matrix type liquid crystal display element in which the arrangement of liquid crystal molecules defined by the alignment layer arranged on each substrate is changed by generating an electric field parallel to each substrate, the signal wiring or At least two comb-shaped electrode wirings are arranged so as to engage with each other at a position opposed to the scanning wirings.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, at least two comb-shaped electrode wirings are bitely arranged on a light-shielding layer of a counter substrate, and a liquid crystal is sandwiched between the electrode substrate and the counter substrate. The step of generating impurity ions reduces the incorporation of impurity ions into the display electrode by the electric field applied to the pixel electrode on the electrode substrate during display by adsorbing and incorporating impurity ions into the comb-shaped electrode by applying an electric field. Things.

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

FIG. 1 is a plan view of an in-plane switching mode liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the in-plane switching mode liquid crystal display device of this embodiment.

As shown in FIG. 1A, a pattern was formed on the array substrate 1 by etching using chromium for the scanning electrode 2 and the common electrode 3 at a pitch of 240 μm. The material is not limited to chromium, and a conductive single-layer film or a multilayer film such as aluminum or a metal containing aluminum as a main component may be used. Silicon nitride (SiN _x ) is laminated thereon as a TFT insulating film. Next, the switching element 4 that controls the switching function of the TFT is formed by laminating amorphous silicon (α-Si) by a plasma CVD method and forming a pattern by etching. Then, two layers of titanium / aluminum (Ti / Al) are deposited, and thereafter, the signal electrode 5 and the pixel electrode 6 having a pitch of 80 μm are etched.
Is patterned as shown in FIG. The material is not limited to titanium / aluminum (Ti / Al), and a single-layer film or a multilayer film of a conductive metal may be used. At this time, the interval between the common electrode 3 and the pixel electrode 6 is 10 μm. Then, an insulating layer of silicon nitride (SiN _x ) is formed to form an array substrate 1.

On an opposing substrate 7 opposing the array substrate 1,
A color filter layer 8 and a light-shielding layer 9 for three colors are formed, and are arranged in parallel with the signal electrodes 5 on the array substrate 1 as shown in FIG.
As shown in (1), electrode wiring (A) 10 and electrode wiring (B) 11 are formed in a comb-like pattern on the light-shielding layer 9 opposite to the signal electrode 5 by etching using chromium so as to mesh with each other. The material of the electrode wirings 10 and 11 is not limited to chromium, and a conductive single-layer film or a multilayer film such as aluminum or a metal containing aluminum as a main component may be used.

Next, a polyamic acid solution (PIX-140 manufactured by Hitachi Chemical Co., Ltd.) is placed on the array substrate 1 and the counter substrate 7 shown in FIG.
2), after printing, a polyimide alignment layer 12 subjected to a thermal condensation treatment at 220 ° C. for 1 hour is formed, and then subjected to an alignment treatment by a rubbing method. As shown in FIG.
And a liquid crystal (Merck: ZLI-4792) 1
A liquid crystal display element is formed by injecting and sandwiching 3 by a vacuum injection method. At this time, the electrode wirings 10 and 11 are arranged on the light shielding layer 9 facing the signal electrode 5.

Next, a current is applied to the electrode wiring (A) 10 and the electrode wiring (B) 11. An electric field is formed on the light-shielding layer 9 formed on the opposite substrate 7 by applying a current,
The impurity ions penetrating into 3 are adsorbed on the alignment layer 12 on the electrode wirings 10 and 11. As a result, since the impurity ion concentration is reduced, it is not adsorbed on the pixel electrode 6 and the common electrode 3 on the array substrate 1 during display, and the occurrence of deterioration in display quality such as an afterimage or a burn-in phenomenon is reduced.

Table 1 shows the relationship between the intensity of the electric field applied to the comb-shaped electrode on the counter substrate 7 and the time until the burn-in phenomenon occurs when the same pattern is displayed. It can be seen that the application time increases the occurrence time of the burn-in phenomenon. In particular, when a DC electric field of 50 V or more was applied for 30 minutes, no burn-in phenomenon was observed even in the same pattern display for 10 hours.

[0020]

[Table 1]

In this embodiment, the two electrode wirings 10 and 11 are formed in a comb shape on the light shielding layer 9 facing the signal electrode 5, but the two electrode wirings 10 and 11 are engaged with the light shielding layer 9 facing the scanning electrode 2. Similar effects were obtained when the comb electrodes were formed.

[0022]

According to the present invention configured as described above, in the lateral electric field mode liquid crystal display element, the electrode wiring is arranged on the light shielding layer of the opposite substrate facing the array substrate to which the electric field related to the display is applied. When an electric field is applied, impurity ions entering during the manufacturing process and impurity ions entering after the completion of the display element are captured on the electrode wiring arranged on the counter substrate. Incorporation of impurity ions into the display electrode by the applied electric field is reduced, and a high-quality liquid crystal display device can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a substrate constituting a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 array substrate 2 scanning electrode 3 common electrode 4 switching element 5 signal electrode 6 pixel electrode 7 counter substrate 8 color filter layer 9 light shielding layer 10 electrode wiring (A) 11 electrode wiring (B) 12 alignment layer 13 liquid crystal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA14 JA24 JB22 JB31 JB51 NA01 PA08 PA11 QA07 5C094 AA03 AA12 AA31 AA43 BA03 BA43 CA19 DA13 DB04 DB10 EA04 EA10 ED15 GB01 5F110 BB01 EE03 EE04 HG15 HG04 HK04 GG03 HL11 NN41

Claims (2)

[Claims] A liquid crystal is sandwiched between an electrode substrate having signal wiring, scanning wiring and pixel electrodes formed on the surface thereof and an opposing substrate having a light shielding layer formed on the surface thereof with an alignment layer interposed therebetween. In a method of manufacturing an active matrix type liquid crystal display element in which a parallel electric field is generated to change the arrangement of liquid crystal molecules defined by the alignment layers disposed on each substrate, the signal wiring or the scanning on the light shielding layer At least two comb-shaped electrode wirings are arranged so as to engage with each other at a position opposite to the wiring, and after interposing a liquid crystal between the substrates, a current is applied to the two comb-shaped electrode wirings to generate an electric field between the comb-shaped electrode wirings. A method for manufacturing an active matrix type liquid crystal display element, comprising a step of generating. 2. A liquid crystal is sandwiched between an electrode substrate having signal wiring, scanning wiring and pixel electrodes formed on the surface thereof and an opposing substrate having a light shielding layer formed on the surface thereof with an alignment layer interposed therebetween. In an active matrix type liquid crystal display element in which a parallel electric field is generated to change the arrangement of liquid crystal molecules defined by the alignment layer disposed on each substrate,
An active matrix type liquid crystal display element, wherein at least two comb-shaped electrode wirings are arranged so as to engage with each other on the light shielding layer at a position facing the signal wirings or the scanning wirings.