LIGHT-EMITTING ELEMENT, LIGHT-EMITTING DEVICE, LIGHTING DEVICE, DISPLAY DEVICE, DISPLAY PANEL, AND ELECTRONIC APPLIANCE

• US 20160043146A1
• Filed: 08/07/2015
• Published: 02/11/2016
• Est. Priority Date: 08/08/2014
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: UESAKA, Shogo, OHSAWA, Nobuharu
• Granted Patent: US 9,653,517 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2101/27 Combination of fluorescent and phosphorescent emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/12 comprising dopants
• CPC Class Codes: H10K 50/13 comprising stacked EL layers within one EL unit
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/818 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 59/30 Devices specially adapted for multicolour light emission
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths
• 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 59/80524 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/877 comprising scattering means

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.

Claims

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 light-emitting layer has a different structure from 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 the first electrode comprises a first reflective layer,

wherein the third electrode comprises a second reflective layer and a light-transmitting 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, 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.

3. The light-emitting device according to claim 2, wherein the second electrode comprises a metal film.

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

wherein the EL layer further comprises a second layer in contact with the first electrode, and

wherein the second layer comprises an acceptor substance.

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

wherein the first electrode comprises indium, tin and oxygen, and

wherein the third electrode comprises titanium.

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 4, 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 light-transmitting layer over the third electrode;

the EL layer over the light-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.