CN103852940B - For fringe field switching mode LCD pixel cell and array base palte - Google Patents

Abstract

The invention discloses a pixel unit for a fringe field switch mode liquid crystal display device, the pixel unit includes a pixel electrode, a common electrode and an insulating layer arranged between the pixel electrode and the common electrode; the common electrode is the same as the common electrode A planar electrode arranged opposite to the pixel electrode; the pixel electrode includes a terminal electrode and a first strip electrode, a second strip electrode, and a third strip electrode arranged in parallel, wherein the second strip electrode is arranged on the Between the first strip-shaped electrode and the third strip-shaped electrode, and the shape of the terminal electrode is arc-shaped and connects the ends of the first strip-shaped electrode and the third strip-shaped electrode. The pixel unit proposed by the invention stabilizes the arrangement of the liquid crystal molecules at the control edge by setting the terminal electrodes in an arc shape, and suppresses the disclination phenomenon.

Description

Pixel unit and array substrate for fringe field switching mode liquid crystal display device

technical field

The invention relates to the technical field of liquid crystal display, in particular to a pixel unit and an array substrate for a fringe field switching mode liquid crystal display device.

Background technique

In Thin Film Transistor Liquid Crystal Display (TFT-LCD) products, fringe field switching technology (Fringe Field Switching, FFS for short) can improve the aperture ratio and transmittance of In-Plane-Switching (IPS) mode liquid crystal display .

The liquid crystal display of FFS mode comprises common electrode and pixel electrode, and the distance between common electrode and pixel electrode can be controlled to be less than the distance between upper and lower glass substrates, so that fringe field can be formed between common electrode and pixel electrode, thereby, It can control the liquid crystal molecules located above the pixel electrodes, overcome the defect that the electric field directly above the pixel electrodes of the traditional IPS liquid crystal display is in the vertical direction, and the liquid crystal molecules are not controlled, and greatly improve the aperture ratio and transmittance of the liquid crystal display.

FIG. 1 is a schematic top view of a pixel unit of a conventional FFS mode liquid crystal display. FIG. 2 is a schematic cross-sectional view of a conventional FFS-mode liquid crystal display pixel unit. As shown in FIG. 1 and FIG. 2 , the pixel unit 10 includes a comb-shaped pixel electrode 11 , a planar common electrode 12 and an insulating layer 13 disposed therebetween. Wherein, the pixel electrode 11 includes a plurality of strip electrodes 111 arranged in parallel and a terminal electrode 112 connecting ends of the strip electrodes. After different voltages are applied between the pixel electrode 11 and the common electrode 12 to form a voltage difference, the terminal electrode 112 and the common electrode 12 will move in the Y direction (that is, the direction in which the strip electrodes extend) and the Z direction (that is, perpendicular to the common electrode 12 ). direction of the plane) form the electric field components E _Y and E _Z , respectively. The existence of the above-mentioned electric field components will make the alignment of the liquid crystal molecules at the edge of the pixel unit unstable. Specifically, the electric field components in the Y direction will affect the rotation direction of the liquid crystal molecules in the XY plane, causing disclination (Disclinationlines) phenomenon; The electric field component will cause the liquid crystal molecules to shift in the Z direction, causing disorder.

Contents of the invention

The technical problem to be solved by the present invention is to provide a pixel unit and an array substrate for a fringe field switching mode liquid crystal display device, which can weaken or eliminate the disclination problem at the edge of the pixel unit caused by the terminal electrodes.

For reaching this purpose, the present invention adopts following technical scheme:

A pixel unit for a fringe field switching mode liquid crystal display device, the pixel unit comprising a pixel electrode, a common electrode, and an insulating layer arranged between the pixel electrode and the common electrode;

The common electrode is a planar electrode opposite to the pixel electrode;

The pixel electrode includes a terminal electrode and a first strip-shaped electrode, a second strip-shaped electrode, and a third strip-shaped electrode arranged in parallel, wherein the second strip-shaped electrode is arranged between the first strip-shaped electrode and the first strip-shaped electrode. between the three strip-shaped electrodes, and the shape of the terminal electrode is arc-shaped and connects the ends of the first strip-shaped electrode and the third strip-shaped electrode.

Further, the second strip electrodes are connected to the terminal electrodes.

Further, the second strip electrodes are not connected to the terminal electrodes.

Further, both the pixel electrode and the common electrode are transparent electrodes.

Further, there is a voltage difference between the pixel electrode and the common electrode, so as to generate an electric field between the pixel electrode and the common electrode.

Correspondingly, the present invention also proposes an array substrate for a fringe field switching mode liquid crystal display device, the array substrate comprising:

Intersecting gate lines and data lines, the gate lines and data lines define a pixel area;

A switching device arranged at the crossing position of the gate line and the data line;

a pixel electrode located in the pixel area;

a common electrode covering the array substrate; and

an insulating layer disposed between the pixel electrode and the common electrode;

Wherein, the common electrode is a planar electrode disposed opposite to the pixel electrode;

The pixel electrode includes a terminal electrode and a first strip-shaped electrode, a second strip-shaped electrode, and a third strip-shaped electrode arranged in parallel, and the second strip-shaped electrode is arranged between the first strip-shaped electrode and the third strip-shaped electrode. between the strip-shaped electrodes, and the shape of the terminal electrode is arc-shaped and connects the ends of the first strip-shaped electrode and the third strip-shaped electrode.

Further, the second strip electrodes are connected to the terminal electrodes.

Further, the second strip electrodes are not connected to the terminal electrodes.

Further, both the pixel electrode and the common electrode are transparent electrodes.

Further, there is a voltage difference between the pixel electrode and the common electrode, so as to generate an electric field between the pixel electrode and the common electrode.

The technical solution proposed by the present invention sets the terminal electrodes in an arc shape, so that the electric field components E _Y formed in the Y direction due to the terminal electrodes cancel each other out, thereby stabilizing the arrangement of the liquid crystal molecules at the control edge and suppressing the occurrence of errors.

Description of drawings

FIG. 1 is a top schematic diagram of a pixel unit of a liquid crystal display in an existing FFS mode;

2 is a schematic cross-sectional view of a pixel unit of a liquid crystal display in an existing FFS mode;

FIG. 3 is a schematic top view of a pixel unit according to a first embodiment of the present invention;

4 is a schematic cross-sectional view of a pixel unit according to a first embodiment of the present invention;

FIG. 5 is a schematic top view of a pixel unit according to a second embodiment of the present invention;

6 is a schematic cross-sectional view of a pixel unit according to a second embodiment of the present invention;

Fig. 7a is a schematic diagram of the luminous brightness distribution of the pixel unit of the existing FFS liquid crystal display device;

Fig. 7b is a schematic diagram of the luminance distribution of the pixel unit according to the second embodiment of the present invention;

Fig. 8a is a distribution diagram of liquid crystal molecules on the XZ plane at point C obtained by simulation of the pixel unit of the existing FFS liquid crystal display device;

Fig. 8b is a distribution diagram of liquid crystal molecules in the XZ plane at point C of the pixel unit of the second embodiment of the present invention obtained by simulation;

FIG. 9 is a schematic top view of an array substrate according to a fifth embodiment of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.

A first embodiment of the invention is shown in Figures 3-4.

FIG. 3 is a schematic top view of a pixel unit according to a first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a pixel unit according to a first embodiment of the present invention. As shown in FIG. 3 and FIG. 4 , the pixel unit 300 includes a pixel electrode 31 , a common electrode 32 and an insulating layer 33 (shown in dotted line in FIG. 3 ) disposed between the pixel electrode 31 and the common electrode 32 .

As shown in FIG. 3 and FIG. 4 , according to the first embodiment of the present invention, the common electrode 32 is a planar electrode disposed opposite to the pixel electrode 31 .

As shown in FIG. 3, according to the first embodiment of the present invention, the pixel electrode 31 includes a terminal electrode 314 and a first strip electrode 311, a second strip electrode 312, and a third strip electrode 313 arranged in parallel, wherein The second strip electrode 312 is disposed between the first strip electrode 311 and the third strip electrode 313, and the terminal electrode 314 is arc-shaped and connected to the first strip electrode 311 and the end of the third strip electrode 313.

In this embodiment, as shown in FIG. 3 and FIG. 4 , the second strip electrodes 312 are connected to the terminal electrodes 314 .

In this embodiment, there is a voltage difference between the pixel electrode 31 and the common electrode 32 , so as to generate an electric field between the pixel electrode 31 and the common electrode 32 .

Preferably, both the pixel electrode 31 and the common electrode 32 are transparent electrodes, and the transparent electrodes can be made of indium tin oxide (ITO), indium zinc oxide (IZO) or other transparent conductive materials.

The pixel unit 300 according to the first embodiment of the present invention is suitable for a fringe field switching mode liquid crystal display device, and it is arranged in a pixel area surrounded by gate lines and data lines.

In this embodiment, since the shape of the terminal electrodes 314 is arc-shaped, the electric field components E _Y formed by the terminal electrodes in the Y direction cancel each other, thereby stabilizing the arrangement of the liquid crystal molecules at the control edge and inhibiting the occurrence of errors.

A second embodiment of the invention is shown in Figures 5-6.

FIG. 5 is a schematic top view of a pixel unit according to a second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a pixel unit according to a second embodiment of the present invention. As shown in FIG. 5 and FIG. 6 , the pixel unit 500 includes a pixel electrode 51 , a common electrode 52 and an insulating layer 53 (shown in dotted line in FIG. 5 ) disposed between the pixel electrode 51 and the common electrode 52 .

As shown in FIG. 5 and FIG. 6 , according to the second embodiment of the present invention, the common electrode 52 is a planar electrode disposed opposite to the pixel electrode 51 .

As shown in FIG. 5, according to the second embodiment of the present invention, the pixel electrode 51 includes a terminal electrode 514 and a first strip electrode 511, a second strip electrode 512, and a third strip electrode 513 arranged in parallel, wherein The second strip electrode 512 is disposed between the first strip electrode 511 and the third strip electrode 513, and the terminal electrode 514 is arc-shaped and connected to the first strip electrode 511 and the end of the third strip electrode 513.

In the second embodiment, as shown in FIG. 6 , the second strip electrode 512 is not connected to the terminal electrode 514 , but has an opening 516 .

In the second embodiment, the pixel electrode 51 and the common electrode 52 have a voltage difference, so that an electric field is generated between the pixel electrode 51 and the common electrode 52 .

Preferably, both the pixel electrode 51 and the common electrode 52 are transparent electrodes, and the transparent electrodes can be made of indium tin oxide (ITO), indium zinc oxide (IZO) or other transparent conductive materials.

The pixel unit 500 according to the second embodiment of the present invention is suitable for a fringe field switching mode liquid crystal display device, and it is arranged in a pixel area surrounded by gate lines and data lines.

In this embodiment, since the shape of the terminal electrode 514 is arc-shaped and the second strip electrode 512 is not connected to the terminal electrode 514 (has an opening 516), making it different from the first embodiment of the present invention In comparison, the electric field components E _Y formed in the Y direction due to the terminal electrodes are better canceled out, thereby better stabilizing the arrangement of liquid crystal molecules at the control edge, and further suppressing the disclination phenomenon.

Figures 7-8 are for the existing pixel unit structure and the pixel unit structure of the second embodiment of the present invention, under the premise that a 5v voltage is applied to the pixel electrode and a 0v voltage is applied to the common electrode (in order to form a 5v voltage difference) , and the comparison chart of the parameters of the pixel unit is obtained by simulation.

Fig. 7a is a schematic diagram of the luminance distribution of the pixel unit of the conventional FFS liquid crystal display device. Fig. 7b is a schematic diagram of the luminance distribution of the pixel unit according to the second embodiment of the present invention. The gray scale of the color in the figure represents the brightness of the light at this position. According to the comparison of Figure 7a and Figure 7b, it can be seen that for point C located at the same position on the edge of the pixel unit, the brightness of the existing pixel unit at point C is obviously lower than that of the second pixel of the present invention. The brightness of the pixel unit in the embodiment at point C. Moreover, it can be seen from the comparison that the light emitting brightness of the pixel unit in this embodiment is uniform at the edge position, indicating that the liquid crystal molecules basically have no disclination. However, the brightness of the existing pixel unit at the edge is not uniform, indicating that the liquid crystal molecules have relatively serious disclination.

FIG. 8 a is a distribution diagram of liquid crystal molecules on the XZ plane at point C of a pixel unit of an existing FFS liquid crystal display device obtained through simulation. Fig. 8b is a distribution diagram of liquid crystal molecules in the XZ plane at point C of the pixel unit according to the second embodiment of the present invention obtained by simulation. The cylinders in the figure represent liquid crystal molecules with orientation. As shown in Figure 8a and Figure 8b, among them, the liquid crystal molecules on the right side in Figure 8a are basically arranged perpendicular to the plane of the figure, and no rotation has occurred, while the liquid crystal molecules in Figure 8b have rotated, reflecting better transparency. Lightness.

To sum up, according to the comparison of the electric field distribution and liquid crystal molecule distribution of the existing pixel unit shown in FIGS. The shape of the terminal electrode is set to be arc-shaped and the second strip electrode is set to be disconnected from the terminal electrode, thereby greatly reducing the electric field component in the undesired direction at the edge of the pixel unit, suppressing The occurrence of disclination.

A third embodiment of the invention is shown in FIG. 9 .

FIG. 9 is a schematic top view of an array substrate according to a third embodiment of the present invention. As shown in FIG. 9 , the array substrate 900 includes crossing gate lines 91 and data lines 92 , and the gate lines 91 and data lines 92 define a pixel region 93 . The array substrate 900 also includes a switching device 94 arranged at the intersection of the gate line 91 and the data line 92, a pixel electrode 95 located in the pixel area 93, a common electrode 96 covering the array substrate; Insulation layer 97 between 96.

Wherein, the common electrode 96 is a planar electrode disposed opposite to the pixel electrode 95;

The pixel electrode 95 includes a terminal electrode 954 and a first strip electrode 951, a second strip electrode 952, and a third strip electrode 953 arranged in parallel, and the second strip electrode 952 is arranged on the first strip electrode. between the electrode 951 and the third strip electrode 953 , and the terminal electrode 954 is arc-shaped and connects the ends of the first strip electrode 951 and the third strip electrode 953 .

In this embodiment, as shown in FIG. 9 , the second strip electrodes 952 are connected to the terminal electrodes 954 . In other embodiments, the second strip electrodes 952 may not be connected to the terminal electrodes 954 .

In this embodiment, the pixel electrode 95 and the common electrode 96 have a voltage difference, so as to generate an electric field between the pixel electrode 95 and the common electrode 96 .

Preferably, both the pixel electrode 95 and the common electrode 96 are transparent electrodes, and the transparent electrodes can be made of indium tin oxide (ITO), indium zinc oxide (IZO) or other transparent conductive materials.

In this embodiment, since the shape of the terminal electrodes 954 is arc-shaped, the electric field components E _Y formed by the terminal electrodes in the Y direction cancel each other, thereby stabilizing the arrangement of the liquid crystal molecules at the control edge and inhibiting the occurrence of errors.

Compared with the prior art, the pixel unit and the array substrate proposed by the present invention set the terminal electrodes of the pixel units in a circular arc shape, so that the electric field components E _Y formed in the Y direction due to the terminal electrodes cancel each other out, thereby stabilizing In order to control the arrangement of liquid crystal molecules at the edge, the disclination phenomenon is suppressed.

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention, and the present invention The scope is determined by the scope of the appended claims.

Claims (8)

1. A pixel unit for a fringe field switching mode liquid crystal display device, the pixel unit comprising a pixel electrode, a common electrode and an insulating layer arranged between the pixel electrode and the common electrode; The common electrode is a planar electrode opposite to the pixel electrode; The pixel electrode includes a terminal electrode and a first strip-shaped electrode, a second strip-shaped electrode, and a third strip-shaped electrode arranged in parallel, wherein the second strip-shaped electrode is arranged between the first strip-shaped electrode and the first strip-shaped electrode. between the three strip-shaped electrodes, and the shape of the terminal electrode is arc-shaped and connects the ends of the first strip-shaped electrode and the third strip-shaped electrode, There is a voltage difference between the pixel electrode and the common electrode, so that an electric field is generated between the pixel electrode and the common electrode. Since the shape of the terminal electrode is arc-shaped, the Y direction formed by the terminal electrode The electric field components EY cancel each other out. 2 . The pixel unit for a fringe field switching mode liquid crystal display device according to claim 1 , wherein the second strip electrodes are connected to the terminal electrodes. 3 . The pixel unit for a fringe field switching mode liquid crystal display device according to claim 1 , wherein the second strip electrodes are not connected to the terminal electrodes. 4 . 4 . The pixel unit for a fringe field switching mode liquid crystal display device according to claim 1 , wherein both the pixel electrode and the common electrode are transparent electrodes. 5. An array substrate for a fringe field switching mode liquid crystal display device, comprising: Intersecting gate lines and data lines, the gate lines and data lines define a pixel area; A switching device arranged at the crossing position of the gate line and the data line; a pixel electrode located in the pixel area; a common electrode covering the array substrate; and an insulating layer disposed between the pixel electrode and the common electrode; Wherein, the common electrode is a planar electrode disposed opposite to the pixel electrode; The pixel electrode includes a terminal electrode and a first strip-shaped electrode, a second strip-shaped electrode, and a third strip-shaped electrode arranged in parallel, and the second strip-shaped electrode is arranged between the first strip-shaped electrode and the third strip-shaped electrode. between the strip electrodes, and the terminal electrode is arc-shaped and connects the ends of the first strip electrode and the third strip electrode, There is a voltage difference between the pixel electrode and the common electrode, so that an electric field is generated between the pixel electrode and the common electrode. Since the shape of the terminal electrode is arc-shaped, the Y direction formed by the terminal electrode The electric field components EY cancel each other out. 6 . The array substrate for a fringe field switching mode liquid crystal display device according to claim 5 , wherein the second strip electrodes are connected to the terminal electrodes. 7 . The array substrate for a fringe field switching mode liquid crystal display device according to claim 5 , wherein the second strip electrodes are not connected to the terminal electrodes. 8 . The array substrate for a fringe field switching mode liquid crystal display device according to claim 5 , wherein both the pixel electrode and the common electrode are transparent electrodes.