Light-emitting device

Patent metadata

Field	Value
Publication number	US-9653517-B2
Application number	US-201514820814-A
Country	US
Kind code	B2
Filing date	Aug 7, 2015
Priority date	Aug 8, 2014
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A light-emitting device in which different electrodes in a work function are used in a first light-emitting element and a second light-emitting element are provided. A light-emitting device includes a first light-emitting element and a second light-emitting element. The first light-emitting element includes a first electrode, an EL layer, and a second electrode in this order. The second light-emitting element includes a third electrode, the EL layer, and the second electrode in this order. The EL layer includes a first light-emitting layer, a layer, and a second light-emitting layer in this order. The structure of the first light-emitting layer is different from the structure of the second light-emitting layer. The first light-emitting element and the second light-emitting element are different in a carrier-injection property.

First claim

What is claimed is:

1. A light-emitting device comprising:
a first light-emitting element comprising:
a first electrode;
an EL layer over the first electrode; and
a second electrode over the EL layer; and

a second light-emitting element comprising:
a third electrode;
the EL layer over the third electrode; and
the second electrode over the EL layer,

wherein the EL layer comprises a first light-emitting layer, a first layer over and in contact with the first light-emitting layer, and a second light-emitting layer over and in contact with the first layer,
wherein the first electrode comprises a first reflective layer,
wherein the third electrode comprises a second reflective layer and a light-transmitting layer over the second reflective layer,
wherein a material of the first reflective layer is same as a material of the second reflective layer,
wherein the second electrode has a light-transmitting property,
wherein the EL layer is in contact with the first reflective layer,
wherein a first structure of a substance of the first light-emitting layer is different from a second structure of a substance of the second light-emitting layer, and
wherein the first light-emitting element and the second light-emitting element are different in a carrier-injection property.

2. The light-emitting device according to claim 1 ,
wherein a peak wavelength of emission from the first light-emitting element is shorter than a peak wavelength of emission from the second light-emitting element.

3. The light-emitting device according to claim 1 , wherein the second electrode comprises a metal film.

4. The light-emitting device according to claim 1 ,
wherein the EL layer further comprises a second layer in contact with the first reflective layer, and
wherein the second layer comprises an acceptor substance.

5. The light-emitting device according to claim 1 ,
wherein the first electrode comprises titanium, and
wherein the third electrode comprises indium, tin and oxygen.

6. The light-emitting device according to claim 1 ,
wherein the first light-emitting layer comprises a first compound,
wherein the second light-emitting layer comprises a second compound,
wherein the first compound is different from the second compound.

7. The light-emitting device according to claim 6 , wherein each of the first compound and the second compound is a light-emitting material.

8. The light-emitting device according to claim 6 ,
wherein the first compound is a fluorescent light-emitting material, and
wherein the second compound is a phosphorescent light-emitting material.

9. The light-emitting device according to claim 1 , wherein the first light-emitting element emits blue light.

10. The light-emitting device according to claim 1 ,
wherein the first light-emitting element further comprises a first color filter,
wherein the second light-emitting element further comprises a second color filter,
wherein the first color filter is capable of transmitting light whose color is different from a color of light that the second color filter can transmit.

11. The light-emitting device according to claim 1 ,
wherein the first electrode is electrically connected to a first transistor, and
wherein the third electrode is electrically connected to a second transistor.

12. A display panel comprising:
the light-emitting device according to claim 1 ; and
a driver circuit.

13. A lighting device comprising:
the light-emitting device according to claim 1 ; and
a power switch.

14. An electronic appliance comprising:
the light-emitting device according to claim 1 ; and
an operation button.

15. A light-emitting device comprising:
a first light-emitting element comprising:
a first electrode;
an EL layer over the first electrode; and
a second electrode over the EL layer, the second electrode comprising a metal film; and

a second light-emitting element comprising:
a third electrode;
a transmitting layer over the third electrode;
the EL layer over the transmitting layer; and
the second electrode over the EL layer,

wherein the first electrode and the third electrode comprises the same material,
wherein the EL layer comprises:
a hole-injection layer in contact with the first electrode;
a hole-transport layer in contact with the hole-injection layer; and
a first light-emitting layer in contact with the hole-transport layer,

wherein the hole-injection layer comprises an acceptor substance,
wherein the first light-emitting layer comprises a second light-emitting layer and a third light-emitting layer,
wherein the second light-emitting layer comprises a first light-emitting material,
wherein the third light-emitting layer comprises a second light-emitting material,
wherein an emission peak wavelength of the first light-emitting material is shorter than that of the second light-emitting material,
wherein the first light-emitting material is different from the second light-emitting material, and
wherein the first light-emitting element and the second light-emitting element are different in a carrier-injection property.

16. The light-emitting device according to claim 15 ,
wherein each of the first electrode and the third electrode is a reflective layer,
wherein the second electrode has a light-transmitting property, and
wherein a peak wavelength of emission from the first light-emitting element is shorter than a peak wavelength of emission from the second light-emitting element.

17. The light-emitting device according to claim 15 ,
wherein the first light-emitting element further comprises a first color filter,
wherein the second light-emitting element further comprises a second color filter,
wherein the first color filter is capable of transmitting light whose color is different from a color of light that the second color filter can transmit.

18. The light-emitting device according to claim 15 ,
wherein the first electrode is electrically connected to a first transistor, and
wherein the third electrode is electrically connected to a second transistor.

19. A display panel comprising:
the light-emitting device according to claim 15 ; and
a driver circuit.

20. A lighting device comprising:
the light-emitting device according to claim 15 ; and
a power switch.

21. An electronic appliance comprising:
the light-emitting device according to claim 15 ; and
an operation button.

22. The light-emitting device according to claim 15 , wherein the third light-emitting layer is positioned over the second light-emitting layer.

23. The light-emitting device according to claim 15 , wherein the hole-injection layer comprises two layers.

Assignees

• Semiconductor Energy Lab

Inventors

• Uesaka Shogo
• Ohsawa Nobuharu

Classifications

• H10K59/877

  comprising scattering means · CPC title

• H10K59/80524

  Transparent cathodes, e.g. comprising thin metal layers · CPC title

• H10K59/80518

  Reflective anodes, e.g. ITO combined with thick metallic layers · CPC title

• H10K59/32

  Stacked devices having two or more layers, each emitting at different wavelengths · CPC title

• H10K59/30 Primary

  Devices specially adapted for multicolour light emission · CPC title