KR100433662B1 - Apparatus for In Plane Switching Liquid Crystal Display - Google Patents

Abstract

The present invention discloses an in-plane switching liquid crystal display device. The disclosed in-plane switching liquid crystal display device includes an in-plane switching liquid crystal display device in which a counter electrode and a pixel electrode are disposed on a single substrate to form a transverse electric field in a liquid crystal cell between a lower substrate and an upper substrate. A thin film transistor portion including a gate, a gate insulating layer, an active layer, and a source / drain, a pixel portion on which a counter electrode and a pixel electrode are disposed, and a data line portion including a gate insulating layer, an active layer, and a data line are formed on the substrate. Low dielectric constant resin layers are formed on the thin film transistor unit and the data line unit, respectively, which serve as a protective layer and a spacer for maintaining cell gaps. The counter electrode and pixel electrode of the pixel unit are disposed on a lower substrate without the presence of an insulating layer. The upper substrate is disposed on the low dielectric constant resin layer, and the low dielectric constant resin layer The only part of the pixel in the liquid crystal is characterized in that it is charged. According to the present invention, crosstalk and afterimage phenomenon can be prevented by removing the insulating film from the pixel portion, light leakage can be prevented by removing the spacer, and the response speed of the liquid crystal can be improved by lowering the cell gap. .

Description

Inplane Switching Liquid Crystal Display {Apparatus for In Plane Switching Liquid Crystal Display}

The present invention relates to an in-plane switching liquid crystal display device, and more particularly, to an in-plane switching liquid crystal display device that can maintain a liquid crystal cell gap without a spacer by generating a step between a pixel region and a data / gate region using a low dielectric material. It is about.

As is well known, In Plane Switching Liquid Crystal Display is an electrode that drives liquid crystal molecules is formed on the same substrate to improve the viewing angle characteristics of the conventional twisted nematic mode liquid crystal display It is proposed to make.

In such an in-plane switching liquid crystal display, a plurality of gate lines and a plurality of data lines are vertically arranged on a lower substrate to form a matrix array. Each of these matrix arrays defines a unit pixel area.

FIG. 1 is a plan view showing a unit pixel area of an in-plane switching liquid crystal display device, in which a pair of gate lines 11 and data lines 13 are shown on a substrate 10. Although not shown in FIG. 1, the gate line 11 and the data line 13 are insulated with the gate insulating film interposed therebetween.

The counter electrode 15 is disposed in the unit pixel region, and the pixel electrode 17 is disposed to overlap a predetermined portion on the counter electrode 15 with a gate insulating film (not shown) therebetween. Here, the storage capacitance Cst is formed at a portion where the counter electrode 15 and the pixel electrode 17 overlap.

The thin film transistor 19 as a switching element is provided at the intersection of the gate line 11 and the data line 13, and includes a gate electrode extending from the gate line 11 and a drain electrode extending from the data line 13; And a channel layer formed on the source electrode and the gate electrode extending from the pixel electrode 17. Here, the gate line 11, the data line 13, the counter electrode 15, and the pixel electrode 17 are made of metal such as aluminum.

In the in-plane switching liquid crystal display, when a scan signal is applied to the gate line 11 and a display signal is applied to the data line 13, the thin film transistor 19 is turned on. Then, the display signal is transmitted to the pixel electrode 17 through the thin film transistor 19 and the common signal is continuously applied to the counter electrode 15. Thus, an electric field is formed between the counter electrode 15 and the pixel electrode 17.

At this time, the electric field formed is almost parallel to the surface of the substrate so that the optical axis of the liquid crystal molecules is twisted parallel to the electric field. Accordingly, the user sees the long axis of the liquid crystal molecules in either direction, thereby improving the viewing angle of the liquid crystal display.

However, the above-described in-plane switching liquid crystal display device has a problem in that an opaque metal such as aluminum is used as the electrode material and the transmittance is low due to the limitation of the transverse electric field between the electrodes. In addition, there is a problem that the afterimage is severe due to the deterioration of the insulating film between the electrodes, and the response speed of the liquid crystal is slow due to the low electric field effect.

Accordingly, the in-plane switching liquid crystal display device according to the present invention is designed to solve the problems of the prior art, and an object of the present invention is to provide a pixel region and a data / gate using a low dielectric constant material for improving transmittance, improving image retention, and providing high-speed response. The present invention provides an in-plane switching liquid crystal display device that can maintain a cell gap without a spacer by generating a step difference in an area.

1 is a cross-sectional view of an in-plane switching liquid crystal display according to the prior art.

2 is a cross-sectional view of the in-plane switching liquid crystal display according to the present invention.

3 is a plan view of the in-plane switching liquid crystal display according to the present invention.

4 is a cross-sectional view showing a gap of a liquid crystal cell at an intersection of a gate line and a data line.

5 is a cross-sectional view showing a sponge liquid crystal injection method.

<Description of the symbols for the main parts of the drawings>

100; Lower substrate 105; Gate electrode

110; A gate insulating film 112; Active layer

114; Data line 114a; Source electrode

114b; Dray electrode 116; Resin layer

118; Counter electrode

In the in-plane switching liquid crystal display according to the present invention for achieving the object of the present invention, the in-plane in which the counter electrode and the pixel electrode is disposed on a single substrate to form a transverse electric field in the liquid crystal cell between the lower substrate and the upper substrate A switching liquid crystal display device comprising: a thin film transistor portion including a gate, a gate insulating film, an active layer, and a source / drain on a lower substrate, a pixel portion on which a counter electrode and a pixel electrode are disposed, a gate insulating film, an active layer, and a data line A low dielectric constant resin layer is formed on the thin film transistor unit and the data line unit to serve as a protective layer and a spacer for maintaining a cell gap, respectively, and the counter electrode and the pixel electrode of the pixel unit are formed of an insulating film. Is disposed on the lower substrate without being present, the upper substrate on the low dielectric constant resin layer The liquid crystal is disposed only in the pixel portion between the low dielectric constant resin layers.

Hereinafter, an in-plane switching liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view of the in-plane switching liquid crystal display according to the present invention, FIG. 3 is a plan view of the in-plane switching liquid crystal display according to the present invention, and FIG. 4 is a view of the liquid crystal cell at the intersection of the gate line and the data line. 5 is a cross-sectional view showing a gap, and FIG. 5 is a cross-sectional view showing a sponge liquid crystal injection method.

As shown in FIG. 2, the in-plane switching liquid crystal display according to the present invention can be divided into a thin film transistor unit, a pixel unit, and a data line unit.

First, the thin film transistor unit includes a gate electrode, a gate insulating layer, an active layer, and a source / drain electrode on the lower substrate. The pixel unit includes a counter electrode and a pixel electrode, and the data line unit includes a gate insulating layer and an active layer. And a data line.

Here, a low dielectric resin layer is formed on the thin film transistor unit and the data line unit as a substitute material for the protective layer. Examples of the low dielectric constant resin layer material include benzenecyclobutyne, microform or polyimide, and the like.

On the other hand, in the pixel portion, a counter electrode and a pixel electrode are formed on the lower substrate in the absence of the gate insulating film and the low dielectric constant resin layer. This is because after forming low dielectric constant resin layers such as bezencyclobutyne, microform or polyimide, a resin layer is left on the thin film transistor portion and the data line portion using a halftone mask, The resin layer may be formed by removing the resin layer and the gate insulating layer. In this case, an electrode may be formed on the low dielectric constant resin layer, or may not be formed otherwise.

As shown in Fig. 3, in the unit pixel defined by the gate line and the data line, the formation of the storage capacitance is inevitable by the low dielectric constant resin layer, and thus remaining as described above to compensate for the reduction of the storage capacitance. The storage capacitance is formed by the gate insulating film. In other words, the area of storage capacitance is reduced and its value is increased.

In the present invention, since the low dielectric constant resin layer plays a role of maintaining the gap of the liquid crystal cell, the existence of the spacer is not required. Therefore, the gap of the liquid crystal cell is determined by the step height of the region where the gate line and the data line overlap, specifically, as shown in FIG. 4, the distance from the upper surface of the lower substrate to the upper surface of the upper data line. The sum of d1 and the distance d2 from the upper surface of the data line to the lower surface of the upper substrate is determined.

The d1 is 5,000 to 15,000 mm 3 and the d2 is 10,000 to 30,000 mm 3. Therefore, the gap of the liquid crystal cell is at least 15,000 mm 3 and at most 45,000 mm 3.

On the other hand, the present invention also provides a liquid crystal injection method using a liquid crystal sponge to solve the liquid crystal injection problem through the resin layer.

In the liquid crystal injection method using the liquid crystal sponge, as shown in FIG. 5, the pressure is properly adjusted as the liquid crystal bath having the liquid crystal sponge and the pressure control system proceeds on the substrate, and the liquid crystal is discharged through the liquid crystal sponge. While being injected into the substrate. Here, the liquid crystal sponge is formed with a micro tube, the micro tube diameter is 100 to 5,000 micrometers. The liquid crystal sponge material may be polyethylene, propylene, acrylic, vinyl, or the like as a material having a small adhesive force with the liquid crystal.

The injection rate of the liquid crystal is determined by the diameter and pressure of the microtube in the liquid crystal sponge. After completion of the liquid crystal injection, the liquid crystal cell is completed by bonding the upper substrate to sealing.

The embodiments disclosed herein are merely exemplary of any preferred embodiment of the present invention, and are not intended to limit the present invention. In addition, it can implement in various changes within the range which does not deviate from the summary of this invention.

As described above, the in-plane switching liquid crystal display according to the present invention has the following effects.

First, since there is no spacer, light leakage due to the spacer does not occur.

Second, since the gap of the liquid crystal cell can be uniformly achieved, the response speed of BNU and the liquid crystal can be improved.

Third, the reduction in storage capacitance caused by using a low dielectric material can be achieved by remaining the gate insulating film in a portion using a halftone mask to form a storage capacitance, thereby compensating for the reduction in storage capacitance and improving transmittance.

Fourth, crosstalk and light leakage due to the electric field effect between the data line portion and the pixel portion can be prevented.

Fifth, liquid crystal injection and rubbing can be facilitated by leaving the gate insulating film in the thin film transistor portion and the data line portion using a halftone mask.

Sixth, since no insulating film exists between the electrodes in the pixel portion, no afterimage occurs.

Seventh, it is possible to reduce the injection time and nonuniformity by injecting the liquid crystal by the sponge.

Claims (8)

An in-plane switching liquid crystal display device in which a counter electrode and a pixel electrode are disposed on a single substrate to form a transverse electric field in a liquid crystal cell between a lower substrate and an upper substrate. A thin film transistor unit including a gate, a gate insulating layer, an active layer, and a source / drain, a pixel unit including a counter electrode and a pixel electrode, and a data line unit including a gate insulating layer, an active layer, and a data line are formed on the lower substrate. The low dielectric constant resin layer is formed on the thin film transistor unit and the data line unit to serve as a protective layer and a spacer for maintaining a cell gap, respectively. The counter electrode and the pixel electrode of the pixel unit are disposed on a lower substrate without the presence of an insulating layer. And an upper substrate disposed on the low dielectric constant resin layer, and only a liquid crystal is filled in the pixel portion between the low dielectric constant resin layers. delete The method of claim 1, The low dielectric constant resin layer is in-plane switching liquid crystal display, characterized in that any one selected from the group consisting of benzocyclobutin, acrylic, microform and polyimide. The method of claim 1, And a gate insulating film of the thin film transistor portion and the data line portion is left using a halftone mask. The method of claim 1. In-plane switching liquid crystal display device between the lower substrate and the upper substrate is filled with liquid crystal by the liquid crystal injection method using a liquid crystal sponge. The method of claim 5, wherein And the liquid crystal sponge comprises a low adhesion material with a liquid crystal including polyethylene, propylene, acryl or vinyl. The method of claim 5, wherein The liquid crystal sponge is formed with a micro tube, the diameter of the micro tube is in-plane switching liquid crystal display, characterized in that the micrometer. The method of claim 1, And a distance from an upper surface of the lower substrate to an upper surface of the data line is 5,000 to 15,000 ,, and a distance from an upper surface of the data line to an lower surface of the upper substrate is 10,000 to 30,000 Å.