Light emitting device

• US 8,237,179 B2
• Filed: 09/23/2011
• Issued: 08/07/2012
• Est. Priority Date: 01/17/2001
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koyama, Jun, Arao, Tatsuya, Azami, Munehiro
• Primary Examiner(s): Malsawma, Lex
• Application Number:
  US13/241,351
• Publication Number:
  US 20120012888A1
• Time in Patent Office: 319 Days
• Field of Search: 257/89, 257/E27.12, 257/E51.018, 257/E33.005
• US Class Current: 257/89
• 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
• CPC Class Codes: H01L 29/78633 with a light shield
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals

Abstract

A light emitting device is provided which can prevent a change in gate voltage due to leakage or other causes and at the same time can prevent the aperture ratio from lowering. A capacitor storage is formed from a connection wiring line, an insulating film, and a capacitance wiring line. The connection wiring line is formed over a gate electrode and an active layer of a TFT of a pixel, and is connected to the active layer. The insulating film is formed on the connection wiring line. The capacitance wiring line is formed on the insulating film. This structure enables the capacitor storage to overlap the TFT, thereby increasing the capacity of the capacitor storage while keeping the aperture ratio from lowering. Accordingly, a change in gate voltage due to leakage or other causes can be avoided to prevent a change in luminance of an OLED and flickering of screen in analog driving.

Claims

1. A light-emitting device comprising:

a switching transistor and a driving transistor, each including a semiconductor layer;

a source line electrically connected to the semiconductor layer of the switching transistor;

a gate line adjacent to the semiconductor layer of the switching transistor;

a wiring electrically connected to the semiconductor layer of the driving transistor;

an interlayer insulating film over the switching transistor and the driving transistor;

a pixel electrode over and in contact with the interlayer insulating film, wherein the pixel electrode is electrically connected to the semiconductor layer of the driving transistor;

a light emitting layer over the pixel electrode;

a counter electrode over the light emitting layer; and

a conductive film over and in contact with the interlayer insulating film, wherein the conductive film has a region overlapping the wiring.

2. The light-emitting device according to claim 1, wherein the conductive film is a capacitance wiring.

3. The light-emitting device according to claim 1, wherein the conductive film overlaps the semiconductor layer of the switching transistor.

4. The light-emitting device according to claim 1, wherein the pixel electrode contains indium tin oxide.

5. The light-emitting device according to claim 1, wherein the counter electrode contains MgAg.

6. The light-emitting device according to claim 1, wherein the wiring is a power supply line.

7. The light-emitting device according to claim 6, wherein an electric potential of the power supply line is kept constant.

8. The light-emitting device according to claim 1, wherein the light-emitting device is incorporated in one selected from the group consisting of a display device, a camera, a computer, an image reproducing device, a goggle type display, and a cellular phone.

9. A light-emitting device comprising:

a switching transistor and a driving transistor, each including a semiconductor layer;

a source line electrically connected to the semiconductor layer of the switching transistor;

a gate line adjacent to the semiconductor layer of the switching transistor;

a wiring electrically connected to the semiconductor layer of the driving transistor;

an interlayer insulating film over the switching transistor and the driving transistor;

a pixel electrode over and in contact with the interlayer insulating film, wherein the pixel electrode is electrically connected to the semiconductor layer of the driving transistor;

a light emitting layer over the pixel electrode;

a counter electrode over the light emitting layer; and

a conductive film over and in contact with the interlayer insulating film, wherein the conductive film has a region extending in parallel with the gate line.

10. The light-emitting device according to claim 9, wherein the conductive film is a capacitance wiring.

11. The light-emitting device according to claim 9, wherein the conductive film overlaps the semiconductor layer of the switching transistor.

12. The light-emitting device according to claim 9, wherein the pixel electrode contains indium tin oxide.

13. The light-emitting device according to claim 9, wherein the counter electrode contains MgAg.

14. The light-emitting device according to claim 9, wherein the wiring is a power supply line.

15. The light-emitting device according to claim 14, wherein an electric potential of the power supply line is kept constant.

16. The light-emitting device according to claim 9, wherein the light-emitting device is incorporated in one selected from the group consisting of a display device, a camera, a computer, an image reproducing device, a goggle type display, and a cellular phone.

17. A light-emitting device comprising:

a switching transistor and a driving transistor, each including a semiconductor layer;

a source line electrically connected to the semiconductor layer of the switching transistor;

a gate line adjacent to the semiconductor layer of the switching transistor;

a wiring electrically connected to the semiconductor layer of the driving transistor;

an interlayer insulating film over the switching transistor and the driving transistor;

a pixel electrode over and in contact with the interlayer insulating film, wherein the pixel electrode is electrically connected to the semiconductor layer of the driving transistor;

a light emitting layer over the pixel electrode;

a counter electrode over the light emitting layer; and

a conductive film over and in contact with the interlayer insulating film, wherein the conductive film has a region overlapping the wiring and extending in parallel with the gate line.

18. The light-emitting device according to claim 17, wherein the conductive film is a capacitance wiring.

19. The light-emitting device according to claim 17, wherein the conductive film overlaps the semiconductor layer of the switching transistor.

20. The light-emitting device according to claim 17, wherein the pixel electrode contains indium tin oxide.

21. The light-emitting device according to claim 17, wherein the counter electrode contains MgAg.

22. The light-emitting device according to claim 17, wherein the wiring is a power supply line.

23. The light-emitting device according to claim 22, wherein an electric potential of the power supply line is kept constant.

24. The light-emitting device according to claim 17, wherein the light-emitting device is incorporated in one selected from the group consisting of a display device, a camera, a computer, an image reproducing device, a goggle type display, and a cellular phone.