Liquid crystal display device

• US 10,120,245 B2
• Filed: 11/11/2016
• Issued: 11/06/2018
• Est. Priority Date: 12/18/2013
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Tsuruma, Takeyuki, Yamaguchi, Hidemasa
• Primary Examiner(s): Mandala, Michelle
• Application Number:
  US15/349,032
• Publication Number:
  US 20170059950A1
• Time in Patent Office: 725 Days
• Field of Search: None
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: G02F 2202/103 a-Si

Abstract

In order to increase the transmittance around a pixel and to increase the brightness of the screen in an IPS mode liquid crystal display device, a pixel electrode with a slit is formed on a common electrode through an interlayer insulating film. An opening is formed in the common electrode on the outside of the end portion of the pixel electrode as seen in a plane view. Because of the presence of the opening, the electric field lines from the end portion of the pixel electrode reach the layer above the liquid crystal layer and reach further away from the end portion of the pixel electrode, so that it is possible to increase the control ability to the liquid crystal around the pixel. As a result, the pixel transmittance can be increased as a whole and the brightness of the screen can be increased.

Claims

1. A display device comprising:

a TFT substrate having scanning lines extending in a first direction, video signal lines extending in a second direction crossing the first direction, a first electrode overlapped with the scanning lines and the video signal lines, an insulating film formed on the first electrode, and a second electrode formed on the insulating film overlapping with the first electrode; and

a counter substrate opposed to the TFT substrate;

wherein the second electrode is formed in an area surrounded by the scanning lines and the video lines,

the first electrode has an opening formed in the area,

the opening is formed along the second electrode and an edge of the opening in the first direction is apart from the second electrode, in a plan view, and

the edge of the opening is between the second electrode and the video signal lines, in a plan view.

2. The display device according to claim 1,

wherein the distance is in the range of 0.25 μ

m to 5 μ

m.

3. The display device according to claim 1,

wherein the distance is in the range of 0.5 μ

m to 3 μ

m.

4. The display device according to claim 1,

wherein the opening does not overlap the video signal line as seen in a plan view.

5. The display device according to claim 1,

wherein the opening does not overlap the scanning line as seen in a plan view.

6. The display device according to claim 1,

wherein the opening is formed between the video signal line and the second electrode,

wherein a part of the opening overlaps with the second electrode.

7. The display device according to claim 1,

wherein the second electrode is a line shape electrode and does not have a slit.

8. The display device according to claim 1,

wherein the opening does not overlap with the second electrode, in a plan view.

9. The display device according to claim 8,

wherein the opening includes a first opening and a second opening, and

the second electrode is between the first opening and the second opening, in a plan view.

10. The display device according to claim 9,

wherein the second electrode opposes to the first electrode between the first opening and the second opening.

11. The display device according to claim 1,

wherein the TFT substrate has a thin film transistor in the area, and

the second electrode is connected to the thin film transistor through a through hole.

12. The display device according to claim 11,

wherein the first electrode has a hole corresponding to the through hole, and

the hole and the opening are not connected.