LIQUID CRYSTAL DISPLAY DEVICE AND ELECTRONIC DEVICE INCLUDING THE SAME

• US 20110085104A1
• Filed: 10/04/2010
• Published: 04/14/2011
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Arasawa, Ryo, Shishido, Hideaki
• Granted Patent: US 8,482,690 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio
• CPC Class Codes: G09G 2300/0447 for multi-domain technique to improve the viewing angle in a liquid crystal display, such as multi-vertical alignment [MVA]
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors

Abstract

An object is to provide a liquid crystal display device in which a pixel including a thin film transistor using an oxide semiconductor has a high aperture ratio. The liquid crystal display device includes a plurality of pixels each including a thin film transistor and a pixel electrode. The pixel is electrically connected to a first wiring functioning as a scan line. The thin film transistor includes an oxide semiconductor layer over the first wiring with a gate insulating film therebetween. The oxide semiconductor layer is extended beyond the edge of a region where the first wiring is provided. The pixel electrode and the oxide semiconductor layer overlap with each other.

Claims

1. A liquid crystal display device comprising:

a scan line;

a first pixel including a first transistor and a first pixel electrode; and

a second pixel including a second transistor and a second pixel electrode,

wherein the first pixel is electrically connected to the scan line,

wherein the first transistor includes an oxide semiconductor layer, the oxide semiconductor layer being over the scan line with a gate insulating film therebetween,

wherein a width of the oxide semiconductor layer is larger than that of the scan line, and

wherein the second pixel electrode and the oxide semiconductor layer overlap with each other.

2. The liquid crystal display device according to claim 1,

wherein the width of the oxide semiconductor layer is larger than that of the scan line in a channel width direction of the first transistor.

3. The liquid crystal display device according to claim 1,

wherein the width of the oxide semiconductor layer is larger than that of the scan line in a channel length direction of the first transistor.

4. The liquid crystal display device according to claim 1, further comprising an oxide insulating layer,

wherein the oxide insulating layer is over and in contact with at least part of the oxide semiconductor layer.

5. The liquid crystal display device according to claim 4, wherein the oxide insulating layer includes phosphorus or boron.

6. A liquid crystal display device comprising:

a scan line;

a signal line;

a first pixel including a first transistor and a first pixel electrode; and

a second pixel including a second transistor and a second pixel electrode,

wherein the first pixel is electrically connected to the scan line and the signal line,

wherein the first transistor includes an oxide semiconductor layer, the oxide semiconductor layer being over the scan line with a gate insulating film therebetween,

wherein a width of the oxide semiconductor layer is larger than that of the scan line,

wherein the signal line includes a portion which is extended along a longitudinal direction of the scan line and over the scan line, and

wherein the second pixel electrode and the oxide semiconductor layer is overlapped with each other.

7. The liquid crystal display device according to claim 6,

wherein the width of the oxide semiconductor layer is larger than that of the scan line in a channel width direction of the first transistor.

8. The liquid crystal display device according to claim 6,

wherein the width of the oxide semiconductor layer is larger than that of the scan line in a channel length direction of the first transistor.

9. The liquid crystal display device according to claim 6, further comprising an oxide insulating layer,

wherein the oxide insulating layer is over and in contact with at least part of the oxide semiconductor layer.

10. The liquid crystal display device according to claim 9, wherein the oxide insulating layer includes phosphorus or boron.

11. The liquid crystal display device according to claim 6,

wherein the first pixel further comprises an insulating layer, and

wherein the insulating layer is between the gate insulating film and the signal line.

12. The liquid crystal display device according to claim 11,

wherein an edge portion of the oxide semiconductor layer is covered with the insulating layer.

13. A liquid crystal display device comprising:

a scan line;

a signal line;

a first pixel including a first transistor, a first wiring, and a first pixel electrode; and

a second pixel including a second transistor and a second pixel electrode,

wherein the first pixel is electrically connected to the scan line and the signal line,

wherein the first wiring is electrically connected to the first pixel electrode,

wherein the first transistor includes an oxide semiconductor layer, the oxide semiconductor layer being over the scan line with a gate insulating film therebetween,

wherein a width of the oxide semiconductor layer is larger than that of the scan line,

wherein the signal line includes a portion which is extended along a longitudinal direction of the scan line and over the scan line, and

wherein the second pixel electrode and the oxide semiconductor layer is overlapped with each other.

14. The liquid crystal display device according to claim 13,

wherein the width of the oxide semiconductor layer is larger than that of the scan line in a channel width direction of the first transistor.

15. The liquid crystal display device according to claim 13,

wherein the width of the oxide semiconductor layer is larger than that of the scan line in a channel length direction of the first transistor.

16. The liquid crystal display device according to claim 13, further comprising an oxide insulating layer,

wherein the oxide insulating layer is over and in contact with at least part of the oxide semiconductor layer.

17. The liquid crystal display device according to claim 16, wherein the oxide insulating layer includes phosphorus or boron.

18. The liquid crystal display device according to claim 13,

wherein the first pixel further comprises a first insulating layer and a second insulating layer,

wherein the first insulating layer is between the gate insulating film and the signal line, and

wherein the second insulating layer is between the gate insulating film and the first wiring.

19. The liquid crystal display device according to claim 18,

wherein an edge portion of the oxide semiconductor layer is covered with the first insulating layer and the second insulating layer.