Light emitting device

• US 7,402,948 B2
• Filed: 04/24/2003
• Issued: 07/22/2008
• Est. Priority Date: 04/26/2002
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kuwabara, Hideaki, Seo, Satoshi, Yamazaki, Shunpei
• Primary Examiner(s): Patel; Ashok
• Application Number:
  US10/422,380
• Publication Number:
  US 20030201716A1
• Time in Patent Office: 1,916 Days
• Field of Search: 313/506, 313/503, 313/509, 313/492, 313/498, 313/917, 313/512, 313/504, 428/690, 428/917, 445/24, 445/25, 257 79-106, 257/59
• US Class Current: 313/506
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/818 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 50/824 combined with auxiliary electrodes
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/127 comprising two substrates, e.g. display comprising OLED array and TFT driving circuitry on different substrates
• CPC Class Codes: H10K 59/1315 comprising structures specially adapted for lowering the resistance
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/80518 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 59/80522 combined with auxiliary electrodes
• CPC Class Codes: H10K 59/80524 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/875 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 59/878 comprising reflective means

Abstract

Not all of light generated in the light emitting layer comprising the organic material are taken out in the desirable direction. For example, light emitted in the lateral direction (the direction parallel to the substrate face) is not taken out and therefore is a loss. An object of the present invention is to provide a light emitting device structured so as to increase the amount of light which is taken out in a certain direction after emitted from a light emitting element, as well as a method of manufacturing this light emitting device.

In the present invention, an upper end portion of an insulating material 19 that covers an end portion of a first electrode 18 is formed to have a curved surface having a radius of curvature, a second electrode 23a is formed to have a slant face as going from its center portion toward its end portion along the curved surface. Light emitted from a light emitting layer comprising an organic material 20 that is formed on the second electrode 23a is reflected at the slant face of the second electrode 23a to increase the total amount of light taken out in the direction indicated by the arrow in FIG. 1A.

Claims

1. A light emitting device possessing plural light emitting elements, comprising:

a first electrode connected to one of a source region of a thin film transistor and a drain region of the thin film transistor,

an insulating material coveting an end portion of the first electrode,

a second electrode covering a side face of the insulating material and contacting with the first electrode,

a light emitting layer comprising an organic material on the second electrode and a portion of the insulating material, and

a third electrode on the light emitting layer comprising the organic material and a portion of the insulating material,

wherein the insulating material has a curved surface possessing a first radius of curvature in its upper end portion and a curved surface possessing a second radius of curvature in its lower end portion, and the first radius of curvature and the second radius of curvature are 0.2 μ

m to 3 μ

m.

2. A light emitting device according to claim 1, wherein the first electrode is the same in its electric potential as the second electrode, and is one of an anode and a cathode.

3. A light emitting device according to claim 1, wherein the second electrode is formed in a concave shape partially having a curved surface, and reflects a light emitted from the light emitting layer comprising the organic material.

4. A light emitting device according to claim 1, wherein the center portion of the second electrode contacts with the first electrode, and the insulating material exists between the end portion of the first electrode and an end portion of the second electrode.

5. A light emitting device according to claim 1, wherein the third electrode is a conductive film through which a light is transmitted.

6. A light emitting device according to claim 1, wherein the light emitting layer comprising the organic material emitting a monochromatic light, and is combined with a color changing layer.

7. A light emitting device according to claim 1, wherein the light emitting device is one of selected from the group consisting of a video camera, a digital camera, a goggle type display, a car navigation, a personal computer, a DVD player, an electronic game equipment and a portable information terminal.

8. A light emitting device according to claim 1, wherein the second electrode has a slant face, and its slant angle is 30°

to 70°

.

9. A light emitting device according to claim 1, wherein the light emitting layer comprising the organic material comprises one of a material emitting a red light, a material emitting a green light and a material emitting a blue light.

10. A light emitting device according to claim 1, wherein the tight emitting layer comprising the organic material comprises a material emitting a white light, and is combined with a color filter.

11. A light emitting device possessing plural light emitting elements, comprising:

a transistor,

an interlayer insulating film over the transistor,

a first electrode electrically connected to the transistor through a contact hole of the interlayer insulating film,

an insulating material covering an end portion of the first electrode,

a second electrode covering a side face of the insulating material and contacting with the first electrode,

a light emitting layer comprising an organic material on the second electrode and a portion of the insulating material, and

a third electrode on the light emitting layer comprising the organic material and a portion of the insulating material,

wherein the insulating material has a curved surface possessing a first radius of curvature in its upper end portion and a curved surface possessing a second radius of curvature in its lower end portion, and the first radius of curvature and the second radius of curvature are 0.2 μ

m to 3 μ

m.

12. A light emitting device according to claim 11, wherein the first electrode is the same in its electric potential as the second electrode, and is one of an anode and a cathode.

13. A light emitting device according to claim 11, wherein the second electrode is formed in a concave shape partially having a curved surface, and reflects a light emitted from the light emitting layer comprising the organic material.

14. A light emitting device according to claim 11, wherein the center portion of the second electrode contacts with the first electrode, and the insulating material exists between the end portion of the first electrode and an end portion of the second electrode.

15. A light emitting device according to claim 11, wherein the third electrode is a conductive film through which a light is transmitted.

16. A light emitting device according to claim 11, wherein the second electrode has a slant Thee, and its slant angle is 30°

to 70°

.

17. A light emitting device according to claim 11, wherein the light emitting layer comprising the organic material comprises one of a material emitting a red light, a material emitting a green light and a material emitting a blue light.

18. A light emitting device according to claim 11, wherein the light emitting layer comprising the organic material comprises a material emitting a white light, and is combined with a color filter.

19. A light emitting device according to claim 11, wherein the light emitting layer comprising the organic material is a material emitting a monochromatic light, and is combined with a color changing layer.

20. A light emitting device according to claim 11, wherein the light emitting device is one of selected from the group consisting of a video camera, a digital camera, a goggle type display, a ear navigation, a personal computer, a DVD player, an electronic game equipment and a portable information terminal.

21. A light emitting device possessing plural light emitting elements, comprising:

a transistor,

an interlayer insulating film over the transistor,

a first electrode electrically connected to the transistor through a contact hole of the interlayer insulating film,

an insulating material covering an end portion of the first electrode,

a second electrode covering a side face of the insulating material and contacting with the first electrode,

a light emitting layer comprising an organic material on the second electrode and on a portion of the insulating material, and

a third electrode on the light emitting layer comprising the organic material and a portion of the insulating material,

wherein the insulating material has a curved surface possessing a first radius of curvature in its upper end portion and a curved surface possessing a second radius of curvature in its lower end portion, and the first radius of curvature and the second radius of curvature are 0.2 μ

m to 3 μ

m.

22. A light emitting device according to claim 21, wherein the first electrode is the same in its electric potential as the second electrode, and is one of an anode and a cathode.

23. A light emitting device according to claim 21, wherein the second electrode is formed in a concave shape partially having a curved surface, and reflects a light emitted from the light emitting layer comprising the organic material.

24. A light emitting device according to claim 21, wherein the center portion of the second electrode contacts with the first electrode, and the insulating material exists between the end portion of the first electrode and an end portion of the second electrode.

25. A light emitting device according to claim 21, wherein the third electrode is a conductive film through which a light is transmitted.

26. A light emitting device according to claim 21, wherein the second electrode has a slant face, and its slant angle is 30°

to 70°

.

27. A light emitting device according to claim 21, wherein the light emitting layer comprising the organic material comprises one of a material emitting a red light, a material emitting a green light and a material emitting a blue light.

28. A tight emitting device according to claim 21, wherein the light emitting layer comprising the organic material comprises a material emitting a white light, and is combined with a color filter.

29. A light emitting device according to claim 21, wherein the light emitting layer comprising the organic material is a material emitting a monochromatic light, and is combined with a color changing layer.

30. A light emitting device according to claim 21, wherein the light emitting device is one of selected from the group consisting of a video camera, a digital camera, a goggle type display, a car navigation, a personal computer, a DVD player, an electronic game equipment and a portable information terminal.

31. A light emitting device possessing plural light emitting elements, comprising:

a first electrode connected to one of a source region of a thin film transistor and a drain region of the thin film transistor,

an insulating material covering an end portion of the first electrode,

a second electrode containing aluminum covering a side face of the insulating material and contacting with the first electrode,

a light emitting layer comprising an organic material on the second electrode and a portion of the insulating material, and

a third electrode on the light emitting layer comprising the organic material and a portion of the insulating material,

wherein the insulating material has a curved surface possessing a first radius of curvature in its upper end portion and a curved surface possessing a second radius of curvature in its lower end portion, and the first radius of curvature and the second radius of curvature are 0.2μ

m to 3 μ

m.

32. A light emitting device according to claim 31, wherein the first electrode is the same in its electric potential as the second electrode, and is one of an anode and a cathode.

33. A light emitting device according to claim 31, wherein the second electrode is formed in a concave shape partially having a curved surface, and reflects a light emitted from the light emitting layer comprising the organic material.

34. A light emitting device according to claim 31, wherein the center portion of the second electrode contacts with the first electrode, and the insulating material exists between the end portion of the first electrode and an end portion of the second electrode.

35. A light emitting device according to claim 31, wherein the third electrode is a conductive film through which a light is transmitted.

36. A light emitting device according to claim 31, wherein the second electrode has a slant face, and its slant angle is 30°

to 70°

.

37. A light emitting device according to claim 31, wherein the light emitting layer comprising the organic material comprises one of a material emitting a red light, a material emitting a green light and a material emitting a blue light.

38. A light emitting device according to claim 31, wherein the light emitting layer comprising the organic material comprises a material emitting a white light, and is combined with a color filter.

39. A light emitting device according to claim 31, wherein the light emitting layer comprising the organic material is a material emitting a monochromatic light, and is combined with a color changing layer.

40. A light emitting device according to claim 31, wherein the light emitting device is one of selected from the group consisting of a video camera, a digital camera, a goggle type display, a car navigation, a personal computer, a DVD player, an electronic game equipment and a portable information terminal.