EL display device and manufacturing method thereof

• US 8,358,063 B2
• Filed: 06/07/2012
• Issued: 01/22/2013
• Est. Priority Date: 09/03/1999
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Patel, Ashok
• Application Number:
  US13/490,694
• Publication Number:
  US 20120248454A1
• Time in Patent Office: 229 Days
• Field of Search: None
• US Class Current: 313/506
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78627 with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/321 Inverted OLED, i.e. having cathode between substrate and anode
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/822 characterised by their shape
• CPC Class Codes: H10K 50/826 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays
• CPC Class Codes: H10K 59/805 Electrodes
• CPC Class Codes: H10K 59/80521 characterised by their shape
• CPC Class Codes: H10K 59/80523 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 59/877 comprising scattering means
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

Reducing the manufacturing cost of an EL display device and an electronic device furnished with the EL display device is taken as an objective. A textured structure in which projecting portions are formed on the surface of a cathode is used. External stray light is diffusely (irregularly) reflected by the action of the projecting portions when reflected by the surface of the cathode, and therefore a defect in which the face of an observer or the surrounding scenery is reflected in the surface of the cathode can be prevented. This can be completed without using a conventionally necessary high price circular polarizing film, and therefore it is possible to reduce the cost of manufacturing the EL display device.

Claims

1. A display device comprising:

a pixel portion comprising a pixel comprising;

a first transistor;

a second transistor electrically connected to the first transistor; and

a light emitting element electrically connected to the second transistor;

a first gate side driving circuit at a first side of the pixel portion;

a second gate side driving circuit at a second side of the pixel portion; and

wherein a gate electrode of the first transistor comprises a material which is different from a material of a gate wiring line,

wherein an electrode of the light emitting element is electrically connected to one of a source wiring and a drain wiring of the second transistor through a first contact hole,

wherein the one of the source wiring and the drain wiring of the second transistor is electrically connected to a semiconductor film of the second transistor through a second contact hole,

wherein the first contact hole and the second contact hole do not overlap with each other,

wherein a silicon nitride layer is positioned over the light emitting element,

wherein a current flows through the first transistor in a first direction,

wherein a current flows through the second transistor in a second direction,

wherein the first direction intersects with the second direction, and

wherein the display device does not comprise a circular polarizing film.

2. The display device according to claim 1,

wherein a surface of the electrode of the light emitting element has projecting portions.

3. The display device according to claim 1,

wherein a surface of a light emitting layer of the light emitting element has projecting portions.

4. The display device according to claim 1,

wherein a surface of another electrode of the light emitting element has projecting portions.

5. An electroluminescence module comprising the display device according to claim 1 and a flexible print circuit.

6. An electronic device comprising the display device according to claim 1, comprising an operation switch, a battery, or a recording medium.

7. An electronic device comprising the electroluminescence module according to claim 5, comprising an operation switch, a battery, or a recording medium.

8. A display device comprising:

a pixel portion comprising a pixel comprising;

a first transistor comprising a multi-gate structure;

a second transistor electrically connected to the first transistor; and

a light emitting element electrically connected to the second transistor;

a first gate side driving circuit at a first side of the pixel portion;

a second gate side driving circuit at a second side of the pixel portion; and

wherein gate electrodes of the first transistor comprises a material which is different from a material of a gate wiring line,

wherein an electrode of the light emitting element is electrically connected to one of a source wiring and a drain wiring of the second transistor through a first contact hole,

wherein the one of the source wiring and the drain wiring of the second transistor is electrically connected to a semiconductor film of the second transistor through a second contact hole,

wherein the first contact hole and the second contact hole do not overlap with each other,

wherein a silicon nitride layer is positioned over the light emitting element,

wherein a current flows through the first transistor in a first direction,

wherein a current flows through the second transistor in a second direction,

wherein the first direction intersects with the second direction, and

wherein the display device does not comprise a circular polarizing film.

9. The display device according to claim 8,

wherein a surface of the electrode of the light emitting element has projecting portions.

10. The display device according to claim 8,

wherein a surface of a light emitting layer of the light emitting element has projecting portions.

11. The display device according to claim 8,

wherein a surface of another electrode of the light emitting element has projecting portions.

12. An electroluminescence module comprising the display device according to claim 8 and a flexible print circuit.

13. An electronic device comprising the display device according to claim 8, comprising an operation switch, a battery, or a recording medium.

14. An electronic device comprising the electroluminescence module according to claim 12, comprising an operation switch, a battery, or a recording medium.

15. A display device comprising:

a pixel portion comprising a pixel comprising;

a first transistor;

a second transistor electrically connected to the first transistor; and

a light emitting element electrically connected to the second transistor;

a first gate side driving circuit at a first side of the pixel portion;

a second gate side driving circuit at a second side of the pixel portion; and

wherein a gate electrode of the first transistor comprises a material which is different from a material of a gate wiring line,

wherein an electrode of the light emitting element is electrically connected to one of a source wiring and a drain wiring of the second transistor through a first contact hole,

wherein the one of the source wiring and the drain wiring of the second transistor is electrically connected to a semiconductor film of the second transistor through a second contact hole,

wherein the first contact hole and the second contact hole do not overlap with each other,

wherein a silicon nitride layer is positioned over the light emitting element,

wherein a current flows through the first transistor in a first direction,

wherein a current flows through the second transistor in a second direction,

wherein the first direction intersects with the second direction, and

wherein the display device does not comprise an optical film.

16. The display device according to claim 15,

wherein a surface of the electrode of the light emitting element has projecting portions.

17. The display device according to claim 15,

wherein a surface of a light emitting layer of the light emitting element has projecting portions.

18. The display device according to claim 15,

wherein a surface of another electrode of the light emitting element has projecting portions.

19. An electroluminescence module comprising the display device according to claim 15 and a flexible print circuit.

20. An electronic device comprising the display device according to claim 15, comprising an operation switch, a battery, or a recording medium.

21. An electronic device comprising the electroluminescence module according to claim 19, comprising an operation switch, a battery, or a recording medium.

22. A display device comprising:

a pixel portion comprising a pixel comprising;

a first transistor comprising a multi-gate structure;

a second transistor electrically connected to the first transistor; and

a light emitting element electrically connected to the second transistor;

a first gate side driving circuit at a first side of the pixel portion;

a second gate side driving circuit at a second side of the pixel portion; and

wherein gate electrodes of the first transistor comprises a material which is different from a material of a gate wiring line,

wherein an electrode of the light emitting element is electrically connected to one of a source wiring and a drain wiring of the second transistor through a first contact hole,

wherein the one of the source wiring and the drain wiring of the second transistor is electrically connected to a semiconductor film of the second transistor through a second contact hole,

wherein the first contact hole and the second contact hole do not overlap with each other,

wherein a silicon nitride layer is positioned over the light emitting element,

wherein a current flows through the first transistor in a first direction,

wherein a current flows through the second transistor in a second direction,

wherein the first direction intersects with the second direction, and

wherein the display device does not comprise an optical film.

23. The display device according to claim 22,

wherein a surface of the electrode of the light emitting element has projecting portions.

24. The display device according to claim 22,

wherein a surface of a light emitting layer of the light emitting element has projecting portions.

25. The display device according to claim 22,

wherein a surface of another electrode of the light emitting element has projecting portions.

26. An electroluminescence module comprising the display device according to claim 22 and a flexible print circuit.

27. An electronic device comprising the display device according to claim 22, comprising an operation switch, a battery, or a recording medium.

28. An electronic device comprising the electroluminescence module according to claim 26, comprising an operation switch, a battery, or a recording medium.