Light emitting device including plural carbon-based thin film layers

• US 7,038,374 B2
• Filed: 04/04/2003
• Issued: 05/02/2006
• Est. Priority Date: 04/05/2002
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kuwabara, Hideaki, Yamazaki, Shunpei
• Primary Examiner(s): Guharay, Karabi
• Application Number:
  US10/406,564
• Publication Number:
  US 20040012331A1
• Time in Patent Office: 1,124 Days
• Field of Search: 313/504, 313/506, 313/512, 313/110, 428/690, 428/917, 315/169.3
• US Class Current: 313/506
• CPC Class Codes: H10K 50/87 Arrangements for heating or cooling
• CPC Class Codes: H10K 59/8794 Arrangements for heating and cooling
• CPC Class Codes: H10K 85/146 poly N-vinylcarbazol; Derivatives thereof
• CPC Class Codes: H10K 85/60 Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence
• CPC Class Codes: H10K 85/649 Aromatic compounds comprising a hetero atom
• CPC Class Codes: H10K 85/6565 Oxadiazole compounds

Abstract

When a light emitting element is actuated to allow the light emission, the generation of Joule heat occurs, leading to the decomposition or crystallization of an organic compound to cause the degradation of the light emitting device. Therefore, a light emitting element of the present invention is provided for effecting removing or decreasing the generation of heat. In the present invention, between two electrodes, layers having organic compounds and carbon-based thin films are alternatively laminated one after another for stepping down the driving voltage in the light emitting element using the tunnel effect. In addition, a carbon-based thin film is placed on a film containing an organic compound, so that it prevents the electric filed from being locally concentrated and also prevents the generation of short-circuit between the anode and the cathode.

Claims

1. A light emitting device comprising a plurality of light emitting elements over a substrate having an insulating surface, wherein each of the light emitting elements comprises:

a first electrode;

a first layer comprising an organic compound formed over the first electrode;

a first carbon-based thin film formed over the first layer;

a second layer comprising an organic compound formed over the first carbon-based thin film;

a second carbon-based thin film over the second layer;

a third layer comprising an organic compound formed over the second carbon-based thin film;

a third carbon-based thin film over the third layer;

a fourth layer comprising an organic compound formed over the third carbon-based thin layer;

a fifth organic layer comprising an organic compound formed over the fourth layer; and

a second electrode provided over the fifth layer comprising an organic layer,

wherein the first carbon-based thin film and the second carbon-based thin film are in direct contact with the second layer, and

wherein the second carbon-based thin film and the third carbon-based thin film are in direct contact with the third layer.

2. A light emitting device according to claim 1, each of the carbon-based thin films is a diamond like carbon film or an amorphous carbon film.

3. A light emitting device according to claim 1, wherein the first layer comprising the organic compound or the fifth layer comprising the organic compound is a layer of transporting or injecting a hole, or a layer of transporting or injecting an electron.

4. A light emitting device according to claim 1, wherein each of the second layer comprising the organic compound, the third layer comprising the organic compound, and the fourth layer comprising the organic compound comprises a material that generates red illumination, a material that generates green illumination, or a material that generates blue illumination.

5. A light emitting device according to claim 1, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates white illumination, and is combined with a color filter mounted over a sealing member.

6. A light emitting device according to claim 1, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates monochroic illumination, and is combined with a color changing layer or a coloring layer provided over the sealing member.

7. An electronic device having the light emitting device according to claim 1, wherein said electronic device is selected from the group consisting of a video camera, a digital camera, a goggles-type display, a car navigation system, a personal computer, a DVD player, an electronic game machine, or a portable information terminal.

8. A light emitting device comprising a plurality of light emitting elements over a substrate having an insulating surface, wherein each of the light emitting elements comprises:

a first electrode;

a first layer comprising an organic compound formed over the first electrode;

a second layer comprising an organic compound formed over the first layer;

a first carbon-based thin film formed over the second layer;

a third layer comprising an organic compound formed over the first carbon-based thin film;

a second carbon-based thin film formed over the third layer;

a fourth layer comprising an organic compound formed over the second carbon-based thin film;

a third carbon-based thin film formed over the fourth layer;

a fifth layer comprising the organic compound formed over the third carbon-based thin film; and

a second electrode provided over the fifih layers,

wherein the first carbon-based thin film and the second carbon-based thin film are in direct contact with the third layer, and

wherein the second carbon-based thin film and the third carbon-based thin film are in direct contact with the fourth layer.

9. A light emitting device according to claim 8, each of the carbon-based thin films is a diamond like carbon film or an amorphous carbon film.

10. A light emitting device according to claim 9, wherein each of the second layer comprising the organic compound, the third layer comprising the organic compound, and the fourth layer comprising the organic compound comprises a material that generates red illumination, a material that generates green illumination, or a material that generates blue illumination.

11. A light emitting device according to claim 9, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates white illumination, and is combined with a color filter mounted over a sealing member.

12. A light emitting device according to claim 9, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates monochroic illumination, and is combined with a color changing layer or a coloring layer provided over the sealing member.

13. An electronic device according to claim 9, wherein the light emitting device is a video camera, a digital camera, a goggles-type display, a car navigation system, a personal computer, a DVD player, an electronic game machine, or a portable information terminal.

14. A light emitting device according to claim 8, wherein the first layer comprising the organic compound or the fifth layer comprising the organic compound is a layer of transporting or injecting a hole, or a layer of transporting or injecting an electron.

15. A light emitting device according to claim 8, wherein each of the second layer comprising the organic compound, the third layer comprising the organic compound, and the fourth layer comprising the organic compound comprises a material that generates red illumination, a material that generates green illumination, or a material that generates blue illumination.

16. A light emitting device according to claim 8, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates white illumination, and is combined with a color filter mounted over a sealing member.

17. A light emitting device according to claim 8, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates monochroic illumination, and is combined with a color changing layer or a coloring layer provided over the sealing member.

18. An electronic device according to claim 8, wherein said electronic device is selected from the group consisting of a video camera, a digital camera, a goggles-type display, a car navigation system, a personal computer, a DVD player, an electronic game machine, or a portable information terminal.

19. A light emitting device comprising a plurality of light emitting elements over a substrate having an insulating surface, wherein each of the light emitting elements comprises:

a first electrode;

a first layer comprising an organic compound formed over the first electrode;

a first carbon-based thin film formed over the first layer;

a second layer comprising an organic compound formed over the first carbon-based thin film;

a second carbon-based thin film formed over the second layer;

a third layer comprising an organic compound formed over the second carbon-based thin film;

a third carbon-based thin film formed over the third layer;

a fourth layer comprising an organic compound formed over the third carbon-based thin film;

a fourth carbon-based thin film formed over the fourth layer;

a fifth layer comprising an organic compound formed over the fourth carbon-based thin film; and

a second electrode provided over the fifth layer,

wherein the first carbon-based thin film and the second carbon-based thin film are in direct contact with the second layer,

wherein the second carbon-based thin film and the third carbon-based thin film are in direct contact with the third layer, and

wherein the third carbon-based thin film and the fourth carbon-based thin film are in direct contact with the fourth layer.

20. A light emitting device according to claim 19, each of the carbon-based thin films is a diamond like carbon film or an amorphous carbon film.

21. A light emitting device according to claim 19, wherein the first layer comprising the organic compound or the fifth layer comprising the organic compound is a layer of transporting or injecting a hole, or a layer of transporting or injecting an electron.

22. A light emitting device according to claim 19, wherein each of the second layer comprising the organic compound, the third layer comprising the organic compound, and the fourth layer comprising the organic compound comprises a material that generates red illumination, a material that generates green illumination, or a material that generates blue illumination.

23. A light emitting device according to claim 19, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates white illumination, and is combined with a color filter mounted over a sealing member.

24. A light emitting device according to claim 19, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates monochroic illumination, and is combined with a color changing layer or a coloring layer provided over the sealing member.

25. An electronic device according to claim 19, wherein said electronic device is selected from the group consisting of a video camera, a digital camera, a goggles-type display, a car navigation system, a personal computer, a DVD player, an electronic game machine, or a portable information terminal.

26. A light emitting device comprising a plurality of light emitting elements over a substrate having an insulating surface, wherein each of the light emitting elements comprises:

a first electrode;

a first layer comprising an organic compound formed over the first electrode;

a second layer comprising an organic compound formed over the first layer;

a first carbon-based thin film formed over the second layer;

a third layer comprising an organic compound formed over the first carbon-based thin film;

a second carbon-based thin film formed over the third layer;

a fourth layer comprising an organic compound formed over the second carbon-based thin layer;

a fifth layer comprising an organic compound formed over the fourth layer; and

a second electrode provided over the fifth layer,

wherein the first carbon-based thin film and the second carbon-based thin film are in direct contact with the third layer, and

wherein the second carbon-based thin film is in direct contact with the fourth layer.

27. A light emitting device according to claim 26, each of the carbon-based thin films is a diamond like carbon film or an amorphous carbon film.

28. A light emitting device according to claim 26, wherein the first layer comprising the organic compound or the fifth layer comprising the organic compound is a layer of transporting or injecting a hole, or a layer of transporting or injecting an electron.

29. A light emitting device according to claim 26, wherein each of the second layer comprising the organic compound, the third layer comprising the organic compound, and the fourth layer comprising the organic compound comprises a material that generates red illumination, a material that generates green illumination, or a material that generates blue illumination.

30. A light emitting device according to claim 26, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates white illumination, and is combined with a color filter mounted over a sealing member.

31. A light emitting device according to claim 26, wherein at least one of the second layer comprising the organic compound, the third layer comprising the organic compound, or the fourth layer comprising the organic compound comprises a material that generates monochroic illumination, and is combined with a color changing layer or a coloring layer provided over the sealing member.

32. An electronic device according to claim 26, wherein the light emitting device is a video camera, a digital camera, a goggles-type display, a car navigation system, a personal computer, a DVD player, an electronic game machine, or a portable information terminal.