WO2006010294A1

WO2006010294A1 - Liquid crystal display device

Info

Publication number: WO2006010294A1
Application number: PCT/CN2004/000865
Authority: WO
Inventors: Zhenyu Liu
Original assignee: Quanta Display Inc.; Quanta Display Japan Inc.
Priority date: 2004-07-26
Filing date: 2004-07-26
Publication date: 2006-02-02

Abstract

The present invention relates to a liquid crystal display device. Said device mainly comprises a substrate, a common line, a gate line, a thin film transistor, a signal line, a protective layer, a flattened insulating layer on the protect layer, and a plurality of pixel electrodes and a plurality of counter electrodes on the flattened insulating layer; wherein the beginning and the end of the pixel electrodes and the counter electrodes are at the same side of the pixel region defined by the gate line and the signal line. And the material of the pixel electrode and the counter electrode are all the transparent conductive material, so the penetration rate is better. The pixel electrode and the counter electrode cross with each other, and are horizontal in a direction paralleled to the signal line, so the wide viewing angle effect is attained.

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device. Background technique

A typical liquid crystal display (LCD) utilizes the optical anisotropy and polarization properties of liquid crystal molecules. Liquid crystal molecules have a clear orientation grade due to their thin and long shape alignment. The alignment direction of the liquid crystal molecules can be controlled by applying an electric field to the liquid crystal molecules. In other words, when the direction of the electric field is changed, the arrangement of the liquid crystal molecules also changes. Since the incident light is refracted to the orientation of the liquid crystal molecules due to the optical anisotropy of the aligned liquid crystal molecules, image data can be displayed.

It is known that liquid crystal molecules are arranged by applying an electric field perpendicularly, and have the advantages of high transparency and high aperture ratio. However, the shortcoming of the liquid crystal display in which liquid crystal molecules are aligned by applying an electric field vertically is narrow. In order to overcome the shortcomings of this narrow viewing angle, coplanar switching has been developed.

(In-plane switching, IPS) liquid crystal display panel. The IPS LCD panel applies an electric field parallel to the substrate that is different from a twisted nematic (TN) or super twisted nematic (STN) LCD panel. These IPS LCDs use a lateral electric field because the pixel electrode and the common electrode are formed on the same substrate. Such IPS LCD devices have the advantages of wide viewing angle and low color dispersion.

An In-Plane Switching Mode (IPS) liquid crystal display device generally includes upper and lower substrates that are parallel to each other and separated from each other, and liquid crystal sandwiched between the upper and lower substrates. A pixel electrode and a common electrode which are parallel to each other and are separated from each other are provided on the lower substrate. The long axis direction of the liquid crystal is twisted and arranged by the transverse electric field between the pixel electrode and the common electrode. But known IPS The LCD uses a non-transparent metal as a counter electrode and a pixel electrode, as described in US Patent Publication No. US 2002-0158994. The pixel area structure of the liquid crystal display disclosed in this patent is as shown in FIG. The portion includes a drain line A, a gate line M, a common electrode B, a pixel electrode (drain layer) F, a counter electrode (ITO) C, a pixel electrode (ITO) D, and A thin film transistor (TFT) disposed at the intersection of the source electrode K, the drain electrode Η, and the semiconductor layer L. Here, a contact hole of the pixel electrode (drain layer) F, a contact hole E of the pixel electrode (ITO) D, and a contact hole I of the drain line A are also included. Although it can provide a wide viewing angle, simplify the manufacturing process and improve the reliability, a pixel electrode in the middle of the Pixel region is composed of an opaque conductive metal, which is easy to cause a decrease in aperture ratio, thereby affecting luminance performance.

Accordingly, there is still a need to develop an IPS LCD having improved aperture ratio and luminance. Summary of the invention

The main object of the present invention is to provide a liquid crystal display device in which the counter electrode and the pixel electrode are both made of a transparent conductive material, which can effectively increase the panel aperture ratio, and reduce the mutual influence between the electrodes by using a planarization insulating layer. .

Another object of the present invention is to provide a liquid crystal display device in which the counter electrode and the pixel electrode are disposed on the same substrate, which can reduce the influence of the vertical electric field on the liquid crystal, and has a large margin for the alignment accuracy of the manufacturing process.

Another object of the present invention is to provide a liquid crystal display device in which a planarization insulating layer is added in a pixel design, and in addition to increasing the surface planarization effect, the influence of the power line caused by the bottom metal line on the liquid crystal can be indirectly reduced. According to the present invention, a liquid crystal display device mainly includes a substrate, a gate line and a signal line defining a pixel region on the substrate, a thin film transistor on a portion intersecting the gate line and the signal line, and a common line, protection a layer, a planarization insulating layer over the protective layer, and a plurality of pixel electrodes and a plurality of counter electrodes over the planarization insulating layer; wherein the pixel electrode and the start and end points of the counter electrode are located on the same side of the pixel region, and the The material of the pixel electrode and the counter electrode are transparent conductive materials.

These and other objects, features and advantages of the present invention will become apparent to those skilled in the < DRAWINGS

1 is a schematic plan view of a known pixel region;

2 is a plan view showing a pixel area in accordance with an embodiment of the present invention; FIG. 3 is a cross-sectional view taken along line AA' of the liquid crystal display device of the present invention of FIG. 2; A schematic plan view of a pixel region of another embodiment of the invention. Simple description of the figure

1 substrate

2 common line

3 protective layer

4 flattening the insulation

5 pixel electrode

6 counter electrode ' 7, 7 gate line

8 insulation

9, 9' signal line

10 source

11 bungee

12 contact hole

13 contact hole

14 amorphous silicon layer

15 doped amorphous silicon layer

16 thin film transistor

In order to achieve the above objects and advantages of the present invention and other additional advantages, the present invention provides a liquid crystal display device including a substrate, a gate line and a signal line defining a pixel region on the substrate, and a gate line and a signal line. a thin film transistor on the intersection portion, a common line, a protective layer, a planarization insulating layer over the protective layer, and a plurality of pixel electrodes and a plurality of counter electrodes over the planarization insulating layer; wherein the pixel electrode and the start and end points of the counter electrode Located on the same side of the pixel region, the pixel electrode and the counter electrode are made of any transparent conductive material selected from the group consisting of indium tin oxide (IT0) and indium zinc oxide (IZ0), whereby the gate line and the signal are The transmittance of the pixel region defined by the line is increased, that is, the aperture ratio is increased to obtain a better transmittance. The pixel electrodes and the fork electrodes extending into the pixel region are juxtaposed with each other, and are horizontally arranged in parallel with the signal line to achieve a wide viewing angle effect of the panel. In addition, the flat is placed above the protective layer The canned insulating layer can increase the surface flatness and reduce the alignment abnormality caused by the poor flatness of the liquid crystal, and further increase the brightness.

According to the liquid crystal display of the present invention, the counter electrode and the pixel electrode may be arranged in a "Z" zigzag arrangement or a linear arrangement or any other arrangement as long as a transverse electric field can be generated therebetween, and only the multi-region liquid crystal alignment is generated. In terms of reducing the color shift, it is preferably arranged in a "Z" shape.

The invention will be described in more detail by reference to the accompanying drawings. Those skilled in the art will appreciate that the drawings are only illustrative of the invention and are not intended to limit the scope thereof.

Please refer to Figure 2 and Figure 3. 2 is a plan view showing a specific embodiment of a liquid crystal display device according to the present invention, and FIG. 3 is a schematic cross-sectional view of the liquid crystal display device of the present invention taken along line AA' of FIG. 2, the liquid crystal display device of the present invention includes a substrate 1, a common line 2 disposed on the substrate 1, a protective layer 3, a planarization layer 4 over the protective layer 3, and a plurality of layers above the protective layer. The pixel electrode 5 and the plurality of counter electrodes 6, and the thin film transistor 16 on the intersection of the gate line 7 and the signal line 9. Next, referring to FIG. 2, a gate line 7, 7' is disposed on the substrate 1, and the insulating layer 8 is over the gate lines 7, 7' and the common line 2. Here, the gate line 7, 7' is overlaid with an insulating layer 8, which is overlaid with an amorphous silicon layer 14 and a doped amorphous silicon layer 15. Among them, the doped amorphous silicon layer 15 is divided by the protective layer 3 and divided into two parts. The source 10 and the drain 11 are symmetrical to the gate line 7 and are respectively placed in two portions of the doped amorphous silicon layer 15. The first signal line 9 and the second signal line 9' are horizontally and parallel to each other and disposed above the insulating layer 8 and disposed on opposite sides of the pixel region, and the second signal line 9' is connected to the source 10. The gate lines 7, 7' intersect with the first and second signal lines 9, 9' to define a pixel area. The drain electrode 11 is connected to the pixel electrode 5 via the contact hole 12, and the common line 2 is connected to the counter electrode 6 via the contact hole 13. In addition, the counter electrode 6 and the pixel electrode 5 may be arranged in a zigzag manner. The start and end points of the pixel electrode 5 and the counter electrode 6 are all on the same side of the pixel region, and the counter electrode 6 surrounds the fork-shaped counter electrode portion in the pixel region, and is surrounded by a "π" font. The periphery of the pixel area. Further, the material of the pixel electrode 5 and the counter electrode 6 is a transparent conductive material, and for example, indium-tin oxide (IT0) or indium-zinc oxide (IZ0) can be used, whereby a better transmittance can be obtained. The fork electrodes extending from the pixel electrode 5 and the counter electrode 6 into the pixel region are juxtaposed and arranged horizontally at a distance and parallel to the signal line. Further, in order to improve the surface flatness, a planarization insulating layer 4 is added to the protective layer 3, and the pixel electrode 5 and the counter electrode 6 are provided thereon. Since the planarization insulating layer 4 can reduce the phenomenon of alignment abnormality of the liquid crystal due to poor surface flatness, and because the planarization insulating layer 4 itself is insulated, the power line induced by the bottom metal line can be indirectly reduced. Impact.

As shown in FIG. 2, the common line 2 is composed of an opaque metal layer which is disposed on one side of the pixel region and is adjacent to the signal line 9 (when the common line is arranged in the lateral direction) or the gate line 7 (as shown in FIG. 2). If the common line is arranged vertically, does not divide or cross the pixel area (pixel transmissive area) and makes the light transmissive area of the entire pixel area a complete large area. In this way, the aperture ratio can be further increased, and the effect of luminance can be increased. The opaque metal layer may be formed of, for example, an opaque conductive metal selected from the group consisting of aluminum (Al), aluminum-niobium alloy (AlNd), tungsten (W), and molybdenum (Mo).

In addition, the portion of the counter electrode 6 adjacent to the signal line 9, 9' may overlap or not overlap with the signal line 9, 9'. For example, as shown in FIG. 2, the portion of the pixel region adjacent to the signal line 9, 9' in the pixel region does not overlap any of the signal lines 9. When the portion of the pixel region adjacent to the signal line 9, 9' overlaps the signal line 9 in the pixel region, the generated lateral electric field can further increase the aperture ratio of the pixel region.

4 shows a specific embodiment of another liquid crystal display device of the present invention, which includes a substrate 1. a common line 2 disposed on the substrate 1, a protective layer 3, a planarization layer 4 over the protective layer 3, a plurality of pixel electrodes 5 and a plurality of counter electrodes 6 above the protective layer, and a gate line 7 and a signal line 9 Thin film transistor 16 on the intersection portion. Referring also to FIG. 2, a gate line 7, V is disposed on the substrate 1, and the insulating layer 8 is over the gate lines 7, 7' and the common line 2. Here, the gate line 7, 7' is overlaid with an insulating layer 8, which is overlaid with an amorphous silicon layer 14 and a doped amorphous silicon layer 15. Among them, the doped amorphous silicon layer 15 is divided by the protective layer 3 and divided into two parts. The source 10 and the drain 11 are symmetrical to the gate line 7 and are respectively placed in two portions of the doped amorphous silicon layer 15. The first signal line 9 and the second signal line 9' are horizontally and parallel to each other and disposed above the insulating layer 8 and disposed on opposite sides of the pixel region, and the second signal line 9' is connected to the source 10. The gate line 7, 7' intersects the first and second signal lines 9, 9' to define a pixel region. The drain electrode 11 is connected to the pixel electrode 5 via the contact hole 12, and the common line 2 is connected to the counter electrode 6 via the contact hole 13. Further, the counter electrode 6 and the pixel electrode 5 are arranged in a line. And wherein the start and end points of the pixel electrode 5 and the counter electrode 6 are on the same side of the pixel region, and the counter electrode 6 is surrounded by a fork-shaped counter electrode portion extending into the pixel region. The periphery of the pixel area. In addition, the material of the pixel electrode 5 and the counter electrode 6 are all transparent conductive materials. The pixel electrodes 5 and the counter electrode 6 extend into the pixel region, and the fork electrodes are juxtaposed at a separation distance and horizontally arranged in parallel with the signal line. Further, in order to improve the surface flatness, the planarization insulating layer 4 is added to the protective layer 3, and the pixel electrode 5 and the counter electrode 6 are provided thereon.

Further, as shown in FIG. 2, the common line 2 is formed of an opaque metal layer which is disposed on one side of the pixel region and is adjacent to the signal line 9 (when the common line is laterally arranged) or the gate line 7 (as shown in FIG. 2). It is shown that if the common line is arranged vertically, the pixel area is not divided or crossed (the pixel light transmission area) and the light transmission area of the entire pixel area is a complete large area. In this way, the opening can be further increased Rate, while increasing the effect of brightness. Similarly, the opaque metal layer may be formed of, for example, an opaque conductive metal selected from the group consisting of aluminum (Al), aluminum-niobium alloy (AlNd), tungsten (W), and molybdenum (Mo).

The effects and advantages of the present invention are described in detail by the above-described embodiments, but are not intended to limit the scope of the present invention. Therefore, equivalent changes and modifications of the shapes, structures, features, and spirits of the present invention are intended to be included within the scope of the appended claims.

Claims

A liquid crystal display device, comprising: a substrate, a gate line and a signal line defining a pixel region on the substrate, a thin film transistor on a portion intersecting the gate line and the signal line, a common line, a protective layer, a planarized insulating layer over the protective layer and a right above the planarized insulating layer

The plurality of pixel electrodes and the plurality of counter electrodes; wherein the pixel electrode and the back electrode have a starting point and a final point on the same side of the pixel region, and the pixel electrode and the counter electrode are made of a transparent conductive material.

The liquid crystal display device according to claim 1, wherein the transparent material is indium-tin oxide (IT0) or indium-zinc oxide (IZ0).

3. The liquid crystal display device according to claim 1, wherein the pixel electrode and the counter electrode are located at the same plane height, so that the effect of the horizontal electric field can be obtained.

The liquid crystal display device according to claim 1 or 3, wherein the pixel electrode and the counter electrode are arranged in a straight strip shape or a "Z" shape.

The liquid crystal display device according to claim 1 or 3, wherein the common line is formed of an opaque metal layer located on a side of the pixel electrode and adjacent to the signal line or the gate line, not dividing or crossing the pixel The area is transparent and the light-transmissive area of the entire pixel area is a complete large-area area.

The liquid crystal display device according to claim 1 or 3, wherein the reverse electrode distribution region in the pixel region does not overlap with the signal line.

The liquid crystal display device according to claim 1 or 3, wherein the reverse electrode distribution region in the pixel region adjacent to the signal line overlaps the signal line.

The liquid crystal display device according to claim 3, wherein the pixel electrode and the counter electrode are juxtaposed and arranged horizontally in parallel with the signal line.

The liquid crystal display device according to claim 3, wherein the pixel electrode and the counter electrode are juxtaposed and arranged horizontally in parallel with the gate line.