Light-emitting device and display device

• US 9,472,601 B2
• Filed: 04/10/2015
• Issued: 10/18/2016
• Est. Priority Date: 02/11/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Seo, Satoshi, Sasaki, Toshiki, Ohsawa, Nobuharu, Ushikubo, Takahiro, Yamazaki, Shunpei
• Primary Examiner(s): Ahmed, Selim
• Assistant Examiner(s): Rahman, Moin
• Application Number:
  US14/683,695
• Publication Number:
  US 20150221703A1
• Time in Patent Office: 557 Days
• Field of Search: 257/13, 257 79-103, 257/918, 257/40, 257642-643, 257/759, 257/E51.001, 257/E51.052, 257E25008-E25009, 438 22- 47, 438/69, 438/493, 438/503, 438/507, 438/956
• US Class Current: 1/1
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/13 comprising stacked EL layers within one EL unit
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 50/816 Multilayers, e.g. transparent multilayers
• CPC Class Codes: H10K 50/818 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

A technique of manufacturing a display device with high productivity is provided. In addition, a high-definition display device with high color purity is provided. By adjusting the optical path length between an electrode having a reflective property and a light-emitting layer by the central wavelength of a wavelength range of light passing through a color filter layer, the high-definition display device with high color purity is provided without performing selective deposition of light-emitting layers. In a light-emitting element, a plurality of light-emitting layers emitting light of different colors are stacked. The closer the light-emitting layer is to the electrode having a reflective property, the longer the wavelength of light emitted from the light-emitting layer is.

Claims

1. A light-emitting device comprising:

a first element comprising;

a first color filter layer; and

a first light-emitting element,

wherein the first light-emitting element comprises;

a first electrode having a reflective property;

a first light-emitting layer over the first electrode; and

a second light-emitting layer over the first light-emitting layer; and

a second element comprising;

a second color filter layer; and

a second light-emitting element,

wherein the second light-emitting element comprises;

a second electrode having a reflective property;

the first light-emitting layer over the second electrode; and

the second light-emitting layer over the first light-emitting layer,

wherein a first optical path length is an optical path length between the first electrode and the first light-emitting layer, and the first optical path length is one-quarter of a first central wavelength of a first wavelength range in which the first color filter layer has a transmittance of 50% or higher in the visible light range,

wherein a second optical path length is an optical path length between the second electrode and the second light-emitting layer, and the second optical path length is m-quarters of a second central wavelength of a second wavelength range in which the second color filter layer has a transmittance of 50% or higher in the visible light range,

wherein m is an odd number of three or more, and

wherein a wavelength of a color of light emitted from the first light-emitting layer is longer than a wavelength of a color of light emitted from the second light-emitting layer.

2. The light-emitting device according to claim 1,

wherein the first central wavelength is a median of the first wavelength range, and

wherein the second central wavelength is a median of the second wavelength range.

3. The light-emitting device according to claim 1,

wherein the first central wavelength is longer than the second central wavelength.

4. The light-emitting device according to claim 1,

wherein the second light-emitting element further comprises a first conductive layer having a light-transmitting property between the second electrode and the first light-emitting layer.

5. The light-emitting device according to claim 4,

wherein the first conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

6. The light-emitting device according to claim 4,

wherein the first light-emitting element further comprises a second conductive layer having a light-transmitting property between the first electrode and the first light-emitting layer, and

wherein the second conductive layer has a different thickness from the first conductive layer.

7. The light-emitting device according to claim 6,

wherein the second conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

8. The light-emitting device according to claim 1, further comprising a charge generation layer between the first light-emitting layer and the second light-emitting layer.

9. The light-emitting device according to claim 1, further comprising an electrode having a light-transmitting property over the second light-emitting layer.

10. The light-emitting device according to claim 1,

wherein the light-emitting device is a display device.

11. The light-emitting device according to claim 1,

wherein the visible light range is 380 nm to 680 nm.

12. A light-emitting device comprising:

a first element comprising;

a first color filter layer; and

a first light-emitting element,

wherein the first light-emitting element comprises;

a first electrode having a reflective property;

a first light-emitting layer over the first electrode; and

a second light-emitting layer over the first light-emitting layer; and

a second element comprising;

a second color filter layer; and

a second light-emitting element,

wherein the second light-emitting element comprises;

a second electrode having a reflective property;

the first light-emitting layer over the second electrode; and

the second light-emitting layer over the first light-emitting layer,

wherein a first optical path length is an optical path length between a surface of the first electrode and a lower surface of the first light-emitting layer or more and an optical path length between the surface of the first electrode and an upper surface of the first light-emitting layer or less,

wherein the first optical path length is one-quarter of a first central wavelength of a first wavelength range in which the first color filter layer has a transmittance of 50% or higher in the visible light range,

wherein a second optical path length is an optical path length between a surface of the second electrode and a lower surface of the second light-emitting layer or more and an optical path length between the surface of the second electrode and an upper surface of the second light-emitting layer or less,

wherein the second optical path length is m-quarters of a second central wavelength of a second wavelength range in which the second color filter layer has a transmittance of 50% or higher in the visible light range,

wherein m is an odd number of three or more, and

wherein a wavelength of a color of light emitted from the first light-emitting layer is longer than a wavelength of a color of light emitted from the second light-emitting layer.

13. The light-emitting device according to claim 12,

wherein the first central wavelength is a median of the first wavelength range, and

wherein the second central wavelength is a median of the second wavelength range.

14. The light-emitting device according to claim 12,

wherein the first central wavelength is longer than the second central wavelength.

15. The light-emitting device according to claim 12,

wherein the second light-emitting element further comprises a first conductive layer having a light-transmitting property between the second electrode and the first light-emitting layer.

16. The light-emitting device according to claim 15,

wherein the first conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

17. The light-emitting device according to claim 15,

wherein the first light-emitting element further comprises a second conductive layer having a light-transmitting property between the first electrode and the first light-emitting layer, and

wherein the second conductive layer has a different thickness from the first conductive layer.

18. The light-emitting device according to claim 17,

wherein the second conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

19. The light-emitting device according to claim 12, further comprising a charge generation layer between the first light-emitting layer and the second light-emitting layer.

20. The light-emitting device according to claim 12, further comprising an electrode having a light-transmitting property over the second light-emitting layer.

21. The light-emitting device according to claim 12,

wherein the light-emitting device is a display device.

22. The light-emitting device according to claim 12,

wherein the visible light range is 380 nm to 680 nm.

23. A light-emitting device comprising:

a first element comprising;

a first color filter layer; and

a first light-emitting element,

wherein the first light-emitting element comprises;

a first electrode having a reflective property;

a first light-emitting layer over the first electrode;

a second light-emitting layer over the first light-emitting layer; and

a third light-emitting layer over the second light-emitting layer;

a second element comprising;

a second color filter layer; and

a second light-emitting element,

wherein the second light-emitting element comprises;

a second electrode having a reflective property;

the first light-emitting layer over the second electrode;

the second light-emitting layer over the first light-emitting layer; and

the third light-emitting layer over the second light-emitting layer; and

a third element comprising;

a third color filter layer; and

a third light-emitting element,

wherein the third light-emitting element comprises;

a third electrode having a reflective property;

the first light-emitting layer over the third electrode;

the second light-emitting layer over the first light-emitting layer; and

the third light-emitting layer over the second light-emitting layer,

wherein a first optical path length is an optical path length between the first electrode and the first light-emitting layer, and the first optical path length is one-quarter of a first central wavelength of a first wavelength range in which the first color filter layer has a transmittance of 50% or higher in the visible light range,

wherein a second optical path length is an optical path length between the second electrode having a reflective property and the second light-emitting layer in the second element, and the second optical path length is m-quarters of a second central wavelength of a second wavelength range in which the second color filter layer has a transmittance of 50% or higher in the visible light range,

wherein a third optical path length is an optical path length between the third electrode having a reflective property and the third light-emitting layer in the third element, and the third optical path length is n-quarters of a third central wavelength of a third wavelength range in which the third color filter layer has a transmittance of 50% or higher in the visible light range,

wherein m is an odd number of three or more, and n is an odd number of three or more,

wherein a wavelength of a color of light emitted from the first light-emitting layer is longer than a wavelength of a color of light emitted from the second light-emitting layer, and

wherein the wavelength of the color of light emitted from the second light-emitting layer is longer than a wavelength of a color of light emitted from the third light-emitting layer.

24. The light-emitting device according to claim 23,

wherein the first central wavelength is a median of the first wavelength range, and

wherein the second central wavelength is a median of the second wavelength range.

25. The light-emitting device according to claim 23,

wherein the first central wavelength is longer than the second central wavelength, and

wherein the second central wavelength is longer than the third central wavelength.

26. The light-emitting device according to claim 23,

wherein the second light-emitting element further comprises a first conductive layer having a light-transmitting property between the second electrode and the first light-emitting layer,

wherein the third light-emitting element further comprises a second conductive layer having a light-transmitting property between the third electrode and the first light-emitting layer, and

wherein the first conductive layer has a different thickness from the second conductive layer.

27. The light-emitting device according to claim 26,

wherein the first conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof, and

wherein the second conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

28. The light-emitting device according to claim 26,

wherein the first light-emitting element further comprises a third conductive layer having a light-transmitting property between the first electrode and the first light-emitting layer, and

wherein the third conductive layer has a different thickness from the first conductive layer and the second conductive layer.

29. The light-emitting device according to claim 28,

wherein the third conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

30. The light-emitting device according to claim 26, further comprising a charge generation layer between the first light-emitting layer and the second light-emitting layer,

wherein the second light-emitting layer is in contact with the third light-emitting layer,

wherein a spectrum of light emitted from the first light-emitting layer has a peak in a range of 600 nm to 700 nm,

wherein a spectrum of light emitted from the second light-emitting layer has a peak in a range of 520 nm to 550 nm, and

wherein a spectrum of light emitted from the third light-emitting layer has a peak in a range of 430 nm to 470 nm.

31. The light-emitting device according to claim 26, further comprising an electrode having a light-transmitting property over the third light-emitting layer.

32. The light-emitting device according to claim 23,

wherein the light-emitting device is a display device.

33. The light-emitting device according to claim 23,

wherein the visible light range is 380 nm to 680 nm.

34. A light-emitting device comprising:

a first element comprising;

a first color filter layer; and

a first light-emitting element,

wherein the first light-emitting element comprises;

a first electrode having a reflective property;

a first light-emitting layer over the first electrode;

a second light-emitting layer over the first light-emitting layer; and

a third light-emitting layer over the second light-emitting layer;

a second element comprising;

a second color filter layer; and

a second light-emitting element,

wherein the second light-emitting element comprises;

a second electrode having a reflective property;

the first light-emitting layer over the second electrode;

the second light-emitting layer over the first light-emitting layer; and

the third light-emitting layer over the second light-emitting layer; and

a third element comprising;

a third color filter layer; and

a third light-emitting element,

wherein the third light-emitting element comprises;

a third electrode having a reflective property;

the first light-emitting layer over the third electrode;

the second light-emitting layer over the first light-emitting layer; and

the third light-emitting layer over the second light-emitting layer,

wherein a first optical path length is an optical path length between a surface of the first electrode and a lower surface of the first light-emitting layer or more and an optical path length between the surface of the first electrode and an upper surface of the first light-emitting layer or less,

wherein the first optical path length is one-quarter of a first central wavelength of a first wavelength range in which the first color filter layer has a transmittance of 50% or higher in the visible light range,

wherein a second optical path length is an optical path length between a surface of the second electrode and a lower surface of the second light-emitting layer or more and an optical path length between the surface of the second electrode and an upper surface of the second light-emitting layer or less,

wherein the second optical path length is m-quarters of a second central wavelength of a second wavelength range in which the second color filter layer has a transmittance of 50% or higher in the visible light range,

wherein a third optical path length is an optical path length between a surface of the third electrode and a lower surface of the third light-emitting layer or more and an optical path length between the surface of the third electrode and an upper surface of the third light-emitting layer or less,

wherein the third optical path length is n-quarters of a third central wavelength of a third wavelength range in which the third color filter layer has a transmittance of 50% or higher in the visible light range,

wherein m is an odd number of three or more, and n is an odd number of three or more,

wherein a wavelength of a color of light emitted from the first light-emitting layer is longer than a wavelength of a color of light emitted from the second light-emitting layer, and

wherein the wavelength of the color of light emitted from the second light-emitting layer is longer than a wavelength of a color of light emitted from the third light-emitting layer.

35. The light-emitting device according to claim 34,

wherein the first central wavelength is a median of the first wavelength range, and

wherein the second central wavelength is a median of the second wavelength range.

36. The light-emitting device according to claim 34,

wherein the first central wavelength is longer than the second central wavelength, and

wherein the second central wavelength is longer than the third central wavelength.

37. The light-emitting device according to claim 34,

wherein the second light-emitting element further comprises a first conductive layer having a light-transmitting property between the second electrode and the first light-emitting layer,

wherein the third light-emitting element further comprises a second conductive layer having a light-transmitting property between the third electrode and the first light-emitting layer, and

wherein the first conductive layer has a different thickness from the second conductive layer.

38. The light-emitting device according to claim 37,

wherein the first conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof, and

wherein the second conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

39. The light-emitting device according to claim 37,

wherein the first light-emitting element further comprises a third conductive layer having a light-transmitting property between the first electrode and the first light-emitting layer, and

wherein the third conductive layer has a different thickness from the first conductive layer and the second conductive layer.

40. The light-emitting device according to claim 39,

wherein the third conductive layer comprises a material selected from a group consisting of indium oxide, indium tin oxide, an indium oxide-zinc oxide alloy, zinc oxide, zinc oxide to which gallium is added, graphene, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, and a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof.

41. The light-emitting device according to claim 37, further comprising a charge generation layer between the first light-emitting layer and the second light-emitting layer,

wherein the second light-emitting layer is in contact with the third light-emitting layer,

wherein a spectrum of light emitted from the first light-emitting layer has a peak in a range of 600 nm to 700 nm,

wherein a spectrum of light emitted from the second light-emitting layer has a peak in a range of 520 nm to 550 nm, and

wherein a spectrum of light emitted from the third light-emitting layer has a peak in a range of 430 nm to 470 nm.

42. The light-emitting device according to claim 37, further comprising an electrode having a light-transmitting property over the third light-emitting layer.

43. The light-emitting device according to claim 34,

wherein the light-emitting device is a display device.

44. The light-emitting device according to claim 34,

wherein the visible light range is 380 nm to 680 nm.