WO2009097797A1

WO2009097797A1 - Transflective liquid crystal display device

Info

Publication number: WO2009097797A1
Application number: PCT/CN2009/070248
Authority: WO
Inventors: Jun Ma; Zhihua Ling
Original assignee: Shanghai Tianma Micro-electronics Co., Ltd.
Priority date: 2008-01-31
Filing date: 2009-01-21
Publication date: 2009-08-13
Also published as: CN101498870B; CN101498870A

Abstract

A transflective liquid crystal display device includes an upper substrate (301), a lower substrate opposite to the upper substrate (301), and a liquid crystal layer sandwiched between the upper substrate (301) and the lower substrate. The lower substrate has scanning lines (208) and data lines (202) which intersect with each other to form pixel regions. Each pixel region includes a reflective region having a reflective electrode (201) and a transmissive region having a transmissive electrode (205). At the border of the reflective electrode (201) and the adjoining transmissive electrode (205), there is an insulating layer (214) between the reflective electrode (201) and the transmissive electrode (205) to isolate the reflective electrode (201) and the transmissive electrode (205).

Description

Reflective transmission type liquid crystal display device

The present application claims priority to Chinese Patent Application No. 20081003334, filed on Jan. 31, 2008, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present invention relates to a liquid crystal display device, and more particularly to a reflective transmissive liquid crystal display device capable of increasing a pixel aperture ratio and reducing a display area to a panel edge distance.

Background technique

With the rapid development of flat panel display technology, liquid crystal display devices are gradually developing in the direction of wide viewing angle, high contrast, and high readability. The liquid crystal display device can be classified into a reflective liquid crystal display device, a transmissive liquid crystal display device, and a reflective transmissive liquid crystal display device according to the display mode employed. Among them, the reflective liquid crystal display device mainly uses the reflection of external light to achieve the display effect, the transmissive liquid crystal display device mainly relies on adding a backlight on the panel to realize the display, and the reflective transmissive liquid crystal display device can reflect external light or rely on The light emitted by the backlight or a combination of the two enables display. Therefore, the reflective transmissive liquid crystal technology which exhibits a good display effect when the ambient light is strong and weak is being widely developed and utilized.

The Chinese patent publication CN101097931A provides a reflective transmission type liquid crystal display device, and Fig. 1 is a cross-sectional view of a substrate under the pixel structure in the prior art. As shown in FIG. 1, the reflective electrode 101 of the lower substrate is disposed on the uppermost layer of the entire substrate, and the transmissive electrode 102 is disposed under the two electrodes. The two electrodes are in direct contact and are connected to the source of the thin film transistor switching element 104 through the via hole, and are organically The film 103 is designed to have a thickness of the liquid crystal layer of the reflective region as half the thickness of the liquid crystal layer of the transmissive region. However, since the material of the reflective electrode 101 is generally a metal having high reflectivity such as A1 or Ag, and the work function of the metal is significantly different from that of the transmissive electrode 102, the reflective electrode directly contacts the transmissive electrode to generate an electrochemistry. In response, the surface metal will be oxidized to reduce the reflectivity. Moreover, if the previous process has been completed, the glass substrate is placed too long before the process of the box, the reflective metal is directly exposed to the air, and some of the reflective metal such as A1 is oxidized to A1 ₂ 0 ₃ , which affects the reflection effect.

In addition, in the prior art, since the reflective electrode of the adjacent pixel and the transmissive electrode of the adjacent pixel are on the same layer, the pixel electrode (reflection electrode or transmissive electrode) of the adjacent pixel is spaced apart by a large distance. , usually 5-6 m, to avoid short circuits between adjacent pixel electrodes and crosstalk between pixels. and so, In the prior art, the pixel aperture ratio is limited because the distance between adjacent pixel electrodes cannot be shortened.

At the same time, the margins from the display area to the edge of the panel reduce the use efficiency of the glass and reduce the area of the display area. Therefore, the flat panel display producer has been working to reduce the margin of the display area to the edge of the panel, but still has not Find the ideal solution.

Summary of the invention

The present invention has been made to solve the above technical problems, and an object thereof is to provide a reflective transmission type liquid crystal display device which can effectively increase an aperture ratio and reduce a distance from a display region to a panel edge, and can prevent oxidation due to direct exposure of a reflective metal. The metal reflectivity is reduced.

In order to achieve the above object, a reflective transmission type liquid crystal display device of the present invention includes: an upper substrate; a lower substrate opposite to the upper substrate; a liquid crystal layer sandwiched between the upper substrate and the lower substrate; a data line disposed on the lower substrate; and a pixel region formed by the intersection of the scan line and the data line; wherein each of the pixel regions includes a reflective region and a transmissive region, and the reflective region is disposed a reflective electrode having a transmissive electrode disposed at an edge of the reflective electrode and an adjacent transmissive electrode, and an insulating layer between the reflective electrode and the transmissive electrode for reflecting the reflection The electrodes are spaced apart from the transmissive electrodes.

Preferably, an insulating layer is disposed at an edge of the pixel region to separate the reflective electrode of the pixel region from the transmissive electrode of an adjacent pixel region.

Preferably, in the pixel region, an insulating layer is disposed between the reflective electrode and the transmissive electrode in a portion where the reflective electrode and the transmissive electrode overlap.

Preferably, in a portion where the reflective electrode and the transmissive electrode overlap, the transmissive electrode is disposed on a side of the reflective electrode adjacent to the liquid crystal layer.

Preferably, the insulating layer extends to a surface of the reflective electrode adjacent to a side of the liquid crystal layer. Preferably, the insulating layer is a transparent insulating layer.

Preferably, the material of the transparent insulating layer comprises SiNx, wherein X is a natural number.

Preferably, the reflective electrode is made of metal.

Preferably, the metal comprises silver or aluminum.

Preferably, the transmissive electrode is composed of ITO, iridium or IGO.

Preferably, the surface of the reflective electrode has a small convex structure. Preferably, the lower substrate further has a thin film transistor switching element disposed on a side of the reflective electrode adjacent to the lower substrate, and having between the reflective electrode and the thin film transistor switching element Organic film.

Preferably, the reflective transmissive liquid crystal display device further includes a color filter, and an aperture is provided on the color filter corresponding to the reflective area.

Preferably, the thickness of the liquid crystal layer corresponding to the reflective region is one-half the thickness of the liquid crystal layer corresponding to the transmissive region.

In order to achieve the above object, the present invention further includes: a reflective transmission type liquid crystal display device, comprising: an upper substrate; a lower substrate disposed opposite to the upper substrate; a liquid crystal layer sandwiched between the upper substrate and the lower substrate Between the scan line and the data line, disposed on the lower substrate; a pixel region formed by the scan line and the data line crossing, each of the pixel regions including a reflective area and a transmissive area, and the reflection a transmissive electrode is disposed in the region, the transmissive region is provided with a transmissive electrode; and scan line leads are formed on the edge of the lower substrate for inputting a scan signal to the scan line, and corresponding to odd-line scan lines and even-line scans a line, provided with an odd row scan line lead and an even row scan line lead; one of the odd row scan line lead and the even row scan line lead is extended by the reflective electrode metal, and the other is formed by a gate The pole metal extends.

Preferably, at the edge of the lower substrate, a pair of the odd row scan line leads and the even row scan line leads are in a stacked structure, and between the odd row scan line leads and the even row scan line leads Set the organic film.

Preferably, the pixel region connected to the scan line lead is disposed as a dummy pixel region, and corresponds to the scan line lead formed by the reflective electrode metal extension, and a via hole is disposed in the dummy pixel region And used to connect the scan line lead and the scan line.

Preferably, an insulating layer is provided on the scan line lead extending from the reflective electrode metal.

Preferably, at the pad to which the scan line lead is connected to the integrated circuit or the flexible circuit board, a transmissive electrode is formed on the metal surface constituting the scan line lead.

The reflective transmissive liquid crystal display device of the present invention has the advantages of avoiding oxidation of the metal layer directly exposed to the air, and suppressing the electrochemical reaction between the reflective metal and the transmissive electrode; and realizing double-layer wiring around the lower substrate, reducing The distance from the display area to the edge of the substrate; the adjacent The distance between the pixels effectively increases the aperture ratio, and in the pixel structure of the present invention, the aperture ratio (reflective display region + transmissive display region) can reach 95% or more.

DRAWINGS

1 is a schematic cross-sectional view of a substrate under a pixel structure in the prior art.

2a is a schematic view showing the pixel structure of a lower substrate of a liquid crystal display device of the present invention.

Fig. 2b is a schematic cross-sectional view showing the pixel structure in the A-A' direction shown in Fig. 1 in the present invention.

Figure 3 is a cross-sectional view showing the structure of the upper substrate of the pixel structure corresponding to the structure of the lower substrate shown in Figure 2b in the present invention.

Fig. 4a is a schematic view showing the structure of a pixel array on the side of the scanning line lead of the liquid crystal display device of the present invention.

Fig. 4b is a schematic view showing the structure of a pixel array near the side of the scanning line of the liquid crystal display device of the present invention.

detailed description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

2a is a schematic view showing the structure of a lower substrate of a liquid crystal display device of the present invention. As shown in FIG. 2a, the pixel structure of the present invention comprises: a thin film transistor (TFT) switching element 204; a data line 202 for inputting a data signal to the pixel, connected to the drain of the switching element 204; a scan line 208 of the scan signal, and a switch The gate of element 204 is connected; the source/drain metal (S/D metal) 211 (shown in Figure 2b) connected to the source of switching element 204; the transmissive electrode 205; the reflective electrode 201; the common (common) line of the pixel 207; the transmissive electrode 205 to the via 203 of the lower S/D metal 211, and the reflective electrode 201 to the via 206 of the underlying S/D metal 211. The reflective electrode is made of a metal such as aluminum or silver. The transmissive electrode 205 may be composed of transparent ITO (Indium Tin Oxides), antimony (indium zinc oxide) or IGO material.

Figure 2b is a cross-sectional view of the pixel structure taken along the AA' direction shown in Figure 2a. As shown in FIG. 2b, a cross-sectional structure 209 of the TFT switching element 204 of the pixel; a small bump structure 210 prepared on the organic film of the substrate reflective region for forming diffuse reflection to prevent specular reflection; The S/D metal 211, the SiNx insulating layer 214, the organic film 213, wherein x is a natural number; the storage capacitor structure 212 of the pixel, and the lower electrode of the capacitor is a common line of pixels composed of a gate metal material. a portion of 207, which provides a common potential from the common line 207 to the lower plate of the storage capacitor. The electrode is an S/D metal 211 connected to the source of the switching element 204; a via 206 connecting the reflective electrode 201 and the S/D metal 211, inputting a potential from the data line 202 to the reflective electrode 201; connecting the transmissive electrode 205 and S The via 203 of the /D metal 211 inputs the potential from the data line 202 to the transmissive electrode 205; the reflective electrode 201 and the transmissive electrode 205 have only a small overlap at the junction, and the transmissive electrode 205 is located above the reflective electrode 201. A SiNx insulating layer 214 is interposed therebetween. In the liquid crystal display device of the present invention, since the SiNx insulating layer 214 is provided on the surface of the reflective electrode, oxidation of the metal constituting the reflective electrode can be prevented, thereby improving product yield.

As shown in Fig. 2b, a SiNx insulating layer 214 is interposed between the reflective electrode 201 and the transmissive electrode 205 disposed above the organic film 213. Moreover, the electrodes of adjacent pixels are not directly adjacent to each other, but the transmissive electrode 205 and the reflective electrode 201 of the adjacent pixel are adjacent to each other through the SiNx insulating layer 214, thereby avoiding the adjacent layer of the same layer metal in the prior art. Short circuit problem between. Moreover, due to the presence of the SiNx layer 214, the spacing d between adjacent pixels can be reduced, and even the spacing d of adjacent pixels can be zero, so that the area of each pixel electrode can be increased to achieve a high aperture ratio.

In the present invention, if the pitch d of the adjacent pixels is set to 0, when the transmissive electrode 205 and the reflective electrode 201 are designed, the interval between the electrodes is determined by the alignment precision between the photolithographic layers, and the alignment between the lithographic layers is usually performed. The precision is lm. Therefore, the interval can be much smaller than the design pitch between the adjacent pixel transmissive electrodes or the reflective electrodes in the prior art, so that the liquid crystal display device of the present invention can significantly increase the aperture ratio of the pixel.

Coating the organic film in the pixel can reduce the parasitic capacitance Cpd between the reflective electrode 201 and the data line 202, and can reduce the parasitic capacitance Cpg between the reflective electrode 201 and the scan line 208. The reflective electrode 201 and the data line 202 can be And the reflective electrode 201 and the scan line 208 are relatively large overlap. And as long as the value of Cpd or Cpg satisfies the display requirement after the reflective electrode 201 overlaps the data line 202 and the scan line 208, the reflective electrode 201 can be extended below the transmissive electrode 205 of the adjacent pixel. Thereby, a reflective electrode is disposed above the data line and the scan line to increase the effective display area of the pixel.

In addition, the transmissive electrode 205 is disposed at the uppermost portion of the entire lower substrate, and can be used as a transmissive electrode at the same time as a pad (pad) where the peripheral lead is connected to an integrated circuit (IC) or a flexible circuit board (FPC). The conductive material of the outer layer is used so that the lower metal layer can be used for the peripheral lead under the transparent ITO layer, and the outermost metal of the lead is protected by the transmissive electrode 205. It is oxidized when exposed to the air.

Figure 3 is a cross-sectional view showing the structure of the upper substrate of the pixel structure corresponding to the structure of the lower substrate shown in Figure 2b in the present invention. As shown in FIG. 3, the liquid crystal display device includes a glass substrate 301 on which a color filter and a transmissive electrode (not shown) are disposed; an organic film protrusion 302 corresponding to the reflective region passes through the pair of organic film protrusions 302. The thickness is set such that the thickness of the liquid crystal layer corresponding to the reflective region is half the thickness of the liquid crystal layer corresponding to the transmissive region.

An opening (not shown) is formed in the color filter corresponding to the reflective area, and is filled with an organic film at the opening position to achieve planarization of the entire substrate to avoid abnormal alignment of the liquid crystal at the opening position. Moreover, due to the presence of the opening, most of the incident light passing through the reflective region passes through the color filter when entering the liquid crystal cell, and is directly emitted without passing through the color filter layer when the liquid crystal cell is exited. The upper substrate structure of the present invention allows the reflective region and the transmissive region to exhibit the same gray scale. Further, in the case where an organic film is formed on the upper substrate, it is not necessary to fabricate a double-cassette structure on the lower substrate, and the stability of the process is improved to some extent.

Fig. 4a is a schematic view showing the structure of a pixel array on the side of the scanning line lead of the liquid crystal display device of the present invention. As shown in FIG. 4a, in a region 407 near the reflective metal electrode on the side of the data line 202 and the transmissive electrode of the adjacent pixel, there is an insulating layer between the reflective electrode and the transmissive electrode, so that between the two layers of the adjacent pixel The distance can be close to each other without generating crosstalk between pixels.

In addition, since the distance between the reflective electrode and the transmissive electrode is very close, and the reflective electrode overlapping the data line can still provide an effective display for the entire pixel, the aperture ratio of the pixel can be effectively improved in the structure. The region 408 near the reflective electrode on the side of the scan line 208 and the adjacent pixel transmissive electrode is similar to the principle described in the region 407, which can reduce the distance between the reflective metal and the transmissive electrode of the adjacent pixel in the region 408, thereby Reduce the pixel spacing and effectively increase the aperture ratio.

As shown in FIG. 4a, the liquid crystal display device according to the present invention further includes: a common lead 401 of the liquid crystal display panel; an odd row scan line lead 404; an even row scan line lead 405; a via 403 for connecting the panel common lead 401 And a common line 207 of pixels, and a common signal is supplied to the pixel array through the via; the dummy pixel 402 of the outermost row of the entire row of pixels.

In the liquid crystal display device of the present invention, the structure of the odd pixel row and the dummy pixel 402 of the even pixel row are different, wherein the dummy pixel of the even pixel row includes the via hole 406 from the even row scanning line lead 405 to the lower layer scanning line metal. In the present invention, the odd-numbered rows corresponding to the scan lines, the odd-line scan line leads 404 It consists of a gate metal and is connected to odd-line display pixels after passing directly through the dummy pixels. Corresponding to the even rows of the scan lines, the even rows of scan line leads 405 are composed of the metal of the reflective electrode layer, the metal of the reflective electrode layer and the scan line metal are separated by an organic film layer, and the even rows of scan line leads 405 are passed through the dummy pixels. The hole 406 and the lower scan line are connected to display the pixel input scan signal to the even line.

In addition, the odd-line scan line leads 404 are disposed under the organic film layer, and are arranged by the gate metal; the even-line scan line leads 405 are disposed above the organic film layer, and the metal layout of the reflective electrode layer is on the lower substrate. At the edge, the two layers of scan line leads can be alternately arranged to achieve double layer wiring. Since the odd-line scan line lead 404 and the even-line scan line lead 405 are double-layered, the lateral distance between the two layers of leads can be small.

Fig. 4b is a schematic view showing the structure of a pixel array near the side of the scanning line of the liquid crystal display device of the present invention. As shown in Figure 4b, odd row scan line leads 404 and even row scan line leads 405 are collected at the edges of the lower substrate glass. Since the odd-line scan line lead 404 and the even-line scan line lead 405 are double-layered, the distance between the two outer leads can be made small, thereby reducing the distance between the display area and the edge of the glass. Moreover, even if the vertical odd-numbered scanning line leads 404 and the even-numbered scanning line leads 405 overlap or partially overlap, since the organic film layer is interposed between the two layers of leads, the parasitic capacitance is relatively small, and crosstalk does not occur. problem.

Therefore, the liquid crystal display device according to the present invention has the following advantages, one of which avoids electrochemical corrosion caused by direct contact between the reflective metal electrode and the transmissive electrode, and prevents oxidation of the reflective metal electrode in the prior art, thereby improving the liquid crystal display device. Yield, optimize display effect; Second, at the edge of the lower substrate glass, the scan line leads can realize double-layer wiring, thereby reducing the distance from the display area to the lower substrate glass, improving the utilization of the glass, and increasing the area of the effective display area; Thirdly, while suppressing crosstalk and short circuit, the distance between the pixel electrode (reflecting electrode and the transmitting electrode) is reduced, and the aperture ratio of the pixel is increased, so that the upper side of the data line and the scanning line can also become a reflective display area. Therefore, the aperture ratio (reflective display area + transmission display area) can be made 95% or more.

According to the liquid crystal display device of the present invention, the pixel aperture ratio can be effectively increased without increasing the process, the spacing between adjacent pixels can be reduced, and the distance from the display region to the edge of the glass plate can be reduced, the display effect can be optimized, and the display effect can be improved. Productivity and lower production costs.

A person skilled in the art will recognize that various modifications and changes can be made thereto without departing from the spirit and scope of the invention. Accordingly, it is intended that the present invention covers the modifications and the modifications

Claims

Rights request

A reflective transmission type liquid crystal display device comprising:

Upper substrate

a lower substrate opposite to the upper substrate;

a liquid crystal layer sandwiched between the upper substrate and the lower substrate;

a scan line and a data line are disposed on the lower substrate;

a pixel region formed by the intersection of the scan line and the data line;

Wherein each of the pixel regions includes a reflective region and a transmissive region, a reflective electrode is disposed in the reflective region, and a transmissive electrode is disposed in the transmissive region.

It is characterized in that an insulating layer is interposed between the reflective electrode and the transmissive electrode at an edge of the reflective electrode and the adjacent transmissive electrode to separate the reflective electrode from the transmissive electrode.

2. The reflective transmissive liquid crystal display device according to claim 1, wherein an insulating layer is disposed at an edge of the pixel region for the reflective electrode of the pixel region and an adjacent pixel region The transmissive electrodes are separated.

The reflective transmission type liquid crystal display device according to claim 1, wherein in the pixel region, the reflective electrode and the transmissive portion are overlapped at a portion where the reflective electrode and the transmissive electrode overlap There is an insulating layer between the electrodes.

The reflective transmissive liquid crystal display device according to claim 3, wherein in the portion where the reflective electrode and the transmissive electrode overlap, the transmissive electrode is disposed adjacent to the liquid crystal layer of the reflective electrode side.

The reflective transmission type liquid crystal display device according to claim 1, wherein the insulating layer extends to a surface of the reflective electrode on a side close to the liquid crystal layer.

The reflective transmission type liquid crystal display device according to any one of claims 1 to 5, wherein the insulating layer is a transparent insulating layer.

The reflective transmission type liquid crystal display device according to claim 6, wherein the material of the transparent insulating layer comprises SiNx, wherein X is a natural number.

The reflection-transmission type liquid crystal display device according to any one of claims 1 to 5, wherein the reflective electrode is made of metal.

The reflective transmission type liquid crystal display device according to claim 8, wherein the metal comprises silver or aluminum.

The reflective transmission type liquid crystal display device according to any one of claims 1 to 5, wherein the transmissive electrode is made of ITO, germanium or IGO.

The reflective transmission type liquid crystal display device according to claim 1, wherein the surface of the reflective electrode has a small convex structure.

The reflective transmissive liquid crystal display device according to claim 1, wherein the lower substrate further has a thin film transistor switching element, and the thin film transistor switching element is disposed on a side of the reflective electrode near the lower substrate And having an organic film between the reflective electrode and the thin film transistor switching element.

The reflective transmissive liquid crystal display device of claim 1, further comprising a color filter, and the color filter corresponding to the reflective region An opening is provided on the upper side.

The reflective transmissive liquid crystal display device according to claim 1, wherein a thickness of the liquid crystal layer corresponding to the reflective region is one-half of a thickness of the liquid crystal layer corresponding to the transmissive region .

15. A reflective transmissive liquid crystal display device comprising:

Upper substrate

a lower substrate disposed opposite to the upper substrate;

a scan line and a data line are disposed on the lower substrate;

a pixel region formed by intersection of the scan line and the data line, each of the pixel regions including a reflective region and a transmissive region, and the reflective region is provided with a reflective electrode, and the transmissive region is provided with a transmissive electrode;

a scan line lead formed on an edge of the lower substrate for inputting a scan signal to the scan line, and corresponding to an odd row scan line and an even row scan line, and having odd row scan line leads and even row scan line leads;

The method is characterized in that one of the odd row scan line leads and the even row scan line leads is extended by the reflective electrode metal, and the other is formed by the gate metal.

16. The reflective transmissive liquid crystal display device according to claim 15, wherein a pair of the odd-numbered row scan line leads and the even-numbered row scan line leads are laminated structures on the lower reverse edge, and An organic film is disposed between the odd row scan line leads and the even row scan line leads.

The reflective transmissive liquid crystal display device according to claim 15, wherein the pixel region connected to the scan line lead is provided as a dummy pixel region, and is formed corresponding to extension of the reflective electrode metal The scan line lead is provided with a via hole in the dummy pixel region for connecting the scan line lead and the scan line.

The reflective transmission type liquid crystal display device according to claim 15, wherein an insulating layer is provided on the scanning line lead extending from the reflective electrode metal.

The reflective transmissive liquid crystal display device according to claim 15, wherein at the pad connecting the scan line lead to the integrated circuit or the flexible circuit board, on a metal surface constituting the scan line lead A transmissive electrode is formed.