IP Library › Granted Patent US 9,847,379
Granted Patent B2
US 9,847,379 · App. 15/061,062 · Granted Dec 19, 2017

Light-emitting device, electronic appliance, and lighting device comprising a light-emitting element having optimized optical path length

Inventor: Kaoru Hatano (Kanagawa, JP)
Assignee: Semiconductor Energy Laboratory Co., Ltd.
H01L27/3211H01L51/504H01L51/5218H01L51/5234H01L51/5265H01L2251/558
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Quick Facts
Patent No.
US 9,847,379
App. No.
15/061,062
Granted
Dec 19, 2017
Kind
B2
Abstract

A light-emitting device and a lighting device each of which includes a plurality of light-emitting elements exhibiting light with different wavelengths are provided. The light-emitting device and the lighting device each have an element structure in which each of the light-emitting elements emits only light with a desired wavelength, and thus the light-emitting elements have favorable color purity. In the light-emitting element emitting light (λ R ) with the longest wavelength of the light with different wavelengths, the optical path length from a reflective electrode to a light-emitting layer (a light-emitting region) included in an EL layer is set to λ R /4 and the optical path length from the reflective electrode to a semi-transmissive and semi-reflective electrode is set to λ R /2.

Claims (70)

1. A light-emitting device comprising:

a first light-emitting element including a first reflective electrode, a first transparent conductive layer in contact with the first reflective electrode, an EL layer in contact with the first transparent conductive layer, and a semi-transmissive and semi-reflective electrode in contact with the EL layer;

a second light-emitting element including a second reflective electrode, a second transparent conductive layer in contact with the second reflective electrode, the EL layer in contact with the second transparent conductive layer, and the semi-transmissive and semi-reflective electrode in contact with the EL layer; and

a third light-emitting element including a third reflective electrode, the EL layer in contact with the third reflective electrode, and the semi-transmissive and semi-reflective electrode in contact with the EL layer,

wherein the EL layer includes a light-emitting layer emitting light with a wavelength λR,

wherein the light with the wavelength λR is emitted from the third light-emitting element, and

wherein, in the third light-emitting element, an optical path length from the third reflective electrode to the light-emitting layer is λR/4 and an optical path length from the third reflective electrode to the semi-transmissive and semi-reflective electrode is λR/2.

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

wherein the EL layer includes one or more of a hole-injection layer, a hole-transport layer, an electron-transport layer, and an electron-injection layer.

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

wherein the first transparent conductive layer is thicker than the second transparent conductive layer.

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

wherein light emitted from the first light-emitting element, light emitted from the second light-emitting element, and light emitted from the third light-emitting element have wavelengths different from each other.

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

wherein the first, second and third reflective electrodes are formed using a same material.

6. An electronic appliance comprising the light-emitting device according to claim 1 .

7. A lighting device comprising the light-emitting device according to claim 1 .

8. A light-emitting device comprising:

a first light-emitting element including a first reflective electrode, a first transparent conductive layer in contact with the first reflective electrode, an EL layer in contact with the first transparent conductive layer, and a semi-transmissive and semi-reflective electrode in contact with the EL layer;

a second light-emitting element including a second reflective electrode, a second transparent conductive layer in contact with the second reflective electrode, the EL layer in contact with the second transparent conductive layer, and the semi-transmissive and semi-reflective electrode in contact with the EL layer; and

a third light-emitting element including a third reflective electrode, the EL layer in contact with the third reflective electrode, and the semi-transmissive and semi-reflective electrode in contact with the EL layer,

wherein the EL layer includes a first light-emitting layer emitting light with a wavelength λR, a second light-emitting layer emitting light with a wavelength λG, and a third light-emitting layer emitting light with a wavelength λB, where a wavelength relation of λR>λG>λB is satisfied,

wherein the light with the wavelength λG is emitted from the first light-emitting element,

wherein, in the first light-emitting element, an optical path length from the first reflective electrode to the second light-emitting layer is 3λG/4 and an optical path length from the first reflective electrode to the semi-transmissive and semi-reflective electrode is λG,

wherein the light with the wavelength λB is emitted from the second light-emitting element,

wherein, in the second light-emitting element, an optical path length from the second reflective electrode to the third light-emitting layer is 3λB/4 and an optical path length from the second reflective electrode to the semi-transmissive and semi-reflective electrode is λB,

wherein the light with the wavelength λR is emitted from the third light-emitting element, and

wherein, in the third light-emitting element, an optical path length from the third reflective electrode to the first light-emitting layer is λR/4 and an optical path length from the third reflective electrode to the semi-transmissive and semi-reflective electrode is λR/2.

9. The light-emitting device according to claim 8 ,

wherein the EL layer includes one or more of a hole-injection layer, a hole-transport layer, an electron-transport layer, and an electron-injection layer.

10. The light-emitting device according to claim 8 ,

wherein the first transparent conductive layer is thicker than the second transparent conductive layer.

11. The light-emitting device according to claim 8 ,

wherein light emitted from the first light-emitting element, light emitted from the second light-emitting element, and light emitted from the third light-emitting element have wavelengths different from each other.

12. The light-emitting device according to claim 8 ,

wherein the first, second and third reflective electrodes are formed using a same material.

13. An electronic appliance comprising the light-emitting device according to claim 8 .

14. A lighting device comprising the light-emitting device according to claim 8 .

15. A light-emitting device comprising:

a first light-emitting element including a first reflective electrode, a first transparent conductive layer in contact with the first reflective electrode, an EL layer in contact with the first transparent conductive layer, and a semi-transmissive and semi-reflective electrode in contact with the EL layer; and

a second light-emitting element including a second reflective electrode, the EL layer in contact with the second reflective electrode, and the semi-transmissive and semi-reflective electrode in contact with the EL layer,

wherein the EL layer includes a light-emitting layer emitting light with a wavelength λR,

wherein the light with the wavelength XR is emitted from the second light-emitting element, and

wherein, in the second light-emitting element, an optical path length from the second reflective electrode to the light-emitting layer is λR/4 and an optical path length from the second reflective electrode to the semi-transmissive and semi-reflective electrode is λR/2.

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

wherein the EL layer includes one or more of a hole-injection layer, a hole-transport layer, an electron-transport layer, and an electron-injection layer.

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

wherein light emitted from the first light-emitting element and light emitted from the second light-emitting element have wavelengths different from each other.

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

wherein the first and second reflective electrodes are formed using a same material.

19. An electronic appliance comprising the light-emitting device according to claim 15 .

20. A lighting device comprising the light-emitting device according to claim 15 .

21. A light-emitting device comprising:

a first light-emitting element including a first reflective electrode, a first transparent conductive layer in contact with the first reflective electrode, an EL layer in contact with the first transparent conductive layer, and a semi-transmissive and semi-reflective electrode in contact with the EL layer;

a second light-emitting element including a second reflective electrode, a second transparent conductive layer in contact with the second reflective electrode, the EL layer in contact with the second transparent conductive layer, and the semi-transmissive and semi-reflective electrode in contact with the EL layer; and

a third light-emitting element including a third reflective electrode, the EL layer in contact with the third reflective electrode, and the semi-transmissive and semi-reflective electrode in contact with the EL layer,

wherein the light with the wavelength λ1 is emitted from the first light-emitting element

wherein the light with the wavelength λ2 is emitted from the second light-emitting element

wherein the light with the wavelength λ3 is emitted from the third light-emitting element,

wherein a wavelength relation of λ3>λ1>λ2 is satisfied,

wherein an optical path length from the first reflective electrode to the semi-transmissive and semi-reflective electrode in the first light-emitting element is longer than an optical path length from the third reflective electrode to the semi-transmissive and semi-reflective electrode in the third light-emitting element, and

wherein an optical path length from the second reflective electrode to the semi-transmissive and semi-reflective electrode in the second light-emitting element is longer than the optical path length from the third reflective electrode to the semi-transmissive and semi-reflective electrode in the third light-emitting element.

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

wherein the EL layer includes one or more of a hole-injection layer, a hole-transport layer, an electron-transport layer, and an electron-injection layer.

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

wherein the first transparent conductive layer is thicker than the second transparent conductive layer.

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

wherein the first, second and third reflective electrodes are formed using a same material.

25. An electronic appliance comprising the light-emitting device according to claim 21 .

26. A lighting device comprising the light-emitting device according to claim 21 .

Priority Claims (1)
JP 2011-085922 · Apr 8, 2011 · national
Continuity (2)
Division 13439329 · Apr 4, 2012
Related Publication 20160190215A1 · Jun 30, 2016