Display device

• US 9,130,067 B2
• Filed: 02/28/2013
• Issued: 09/08/2015
• Est. Priority Date: 10/08/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Akimoto, Kengo, Komori, Shigeki, Uochi, Hideki, Futamura, Tomoya, Kasahara, Takahiro
• Primary Examiner(s): WOJCIECHOWICZ, EDWARD JOSEPH
• Application Number:
  US13/780,138
• Publication Number:
  US 20130175525A1
• Time in Patent Office: 922 Days
• Field of Search: 257/43, 257/59, 257/66, 257/102, 257/103, 257/410, 257/613
• US Class Current: 1/1
• CPC Class Codes: G02F 1/136204 Arrangements to prevent high voltage or static electricity failures
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
• 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 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/0041 characterised by field-effect operation

Abstract

In order to take advantage of the properties of a display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area are necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer over the gate insulating film; a channel protective layer covering a region which overlaps with a channel formation region of the first oxide semiconductor layer; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and over the first oxide semiconductor layer. The gate electrode is connected to a scan line or a signal line, the first wiring layer or the second wiring layer is directly connected to the gate electrode.

Claims

1. A display device comprising:

a substrate;

a scan line;

a signal line intersecting with the scan line over the substrate;

a pixel portion in which pixel electrodes are arranged in matrix; and

a first non-linear element provided over the substrate in a region outside the pixel portion,

wherein the pixel portion comprises a thin film transistor in which a channel formation region is in a first oxide semiconductor layer,

wherein the thin film transistor comprises;

a gate electrode which is connected to the scan line;

a first wiring layer which is connected to the signal line and the first oxide semiconductor layer; and

a second wiring layer which is connected to one of the pixel electrodes and the first oxide semiconductor layer,

wherein the first non-linear element comprises;

a gate electrode;

a second oxide semiconductor layer over the gate electrode of the first non-linear element;

a channel protective layer covering a region which overlaps with a channel formation region of the second oxide semiconductor layer; and

a first wiring layer and a second wiring layer being over the channel protective layer and the gate electrode of the first non-linear element,

wherein the gate electrode of the first non-linear element is connected to the scan line,

wherein one of the first wiring layer and the second wiring layer of the first non-linear element is directly connected to a wiring in the same layer as the gate electrode of the first non-linear element, and

wherein at least one of the first oxide semiconductor layer and the second oxide semiconductor layer includes a nanocrystal.

8. The display device according to claim 1,

wherein the pixel portion comprises an organic electroluminescent element.

11. The display device according to claim 1,

wherein the pixel portion comprises an electrophoretic display element.

13. The display device according to claim 1,

wherein a channel protective layer is on the channel formation region.

16. A module comprising:

the display device according to claim 1; and

a flexible printed circuit electrically connected to the display device.

18. An electronic device comprising the display device according to claim 1.

2. A display device comprising:

a substrate;

a scan line over the substrate;

a signal line intersecting with the scan line over the substrate;

a pixel portion in which pixel electrodes are arranged in matrix;

a gate driver; and

a first element and a second element between the pixel portion and the gate driver,

wherein the first element comprises a first terminal being a gate, a second terminal, and a third terminal,

wherein the second element comprises a fourth terminal being a gate, a fifth terminal, and a sixth terminal,

wherein the pixel portion comprises a thin film transistor comprising an oxide semiconductor layer,

wherein the first terminal is connected to the second terminal and the scan line, the second terminal is connected to the scan line, and the third terminal is connected to a wiring,

wherein the fourth terminal is connected to the fifth terminal and the wiring, the fifth terminal is connected to the wiring, and the sixth terminal is connected to the scan line, and

wherein each of the first element and the second element comprises an oxide semiconductor layer including a nanocrystal.

3. The display device according to claim 2,

wherein the second terminal is a drain, the third terminal is a source, the fifth terminal is a drain, and the sixth terminal is a source.

4. The display device according to claim 2,

wherein each of the first element and the second element is a non-linear element.

9. The display device according to claim 2,

wherein the pixel portion comprises an organic electroluminescent element.

12. The display device according to claim 2,

wherein the pixel portion comprises an electrophoretic display element.

14. The display device according to claim 2,

wherein a channel protective layer is on the oxide semiconductor layer including the nanocrystal.

17. A module comprising:

the display device according to claim 2; and

a flexible printed circuit electrically connected to the display device.

19. An electronic device comprising the display device according to claim 2.

20. The display device according to claim 2,

wherein the wiring is the signal line.

5. A computer comprising:

a display device comprising;

a substrate;

a scan line over the substrate;

a signal line intersecting with the scan line over the substrate;

a pixel portion in which pixel electrodes are arranged in matrix;

a gate driver; and

a first element and a second element between the pixel portion and the gate driver,

wherein the first element comprises a first terminal being a gate, a second terminal, and a third terminal,

wherein the second element comprises a fourth terminal being a gate, a fifth terminal, and a sixth terminal,

wherein the pixel portion comprises a thin film transistor comprising an oxide semiconductor layer,

wherein the first terminal is connected to the second terminal and the scan line, and the second terminal is connected to the scan line, and the third terminal is connected to a wiring,

wherein the fourth terminal is connected to the fifth terminal and the wiring, the fifth terminal is connected to the wiring, and the sixth terminal is connected to the scan line, and

wherein each of the first element and the second element comprises an oxide semiconductor layer and the oxide semiconductor layer including a nanocrystal.

6. The computer according to claim 5,

wherein the second terminal is a drain, the third terminal is a source, the fifth terminal is a drain, and the sixth terminal is a source.

7. The computer according to claim 5,

wherein each of the first element and the second element is a non-linear element.

10. The computer according to claim 5,

wherein the pixel portion comprises an organic electroluminescent element.

15. The computer according to claim 5,

wherein a channel protective layer is on the oxide semiconductor layer including the nanocrystal.

21. The computer according to claim 5,

wherein the wiring is the signal line.