Light-Emitting Device and Display Device

• US 20170025479A1
• Filed: 10/10/2016
• Published: 01/26/2017
• 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
• Granted Patent: US 10,741,619 B2
• Time in Patent Office: Days
• 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. (canceled)

2. A light-emitting device, comprising a plurality of pixels on a substrate, wherein each pixel comprises:

a transistor;

a light-emitting element further away from the substrate than the transistor and driven by the transistor, the light-emitting element sequentially comprising a first electrode, a light-emitting layer, and a second electrode having a light-transmitting property in a direction away from the substrate, wherein the first electrode is a layer having a reflective property, or the first electrode has a light-transmitting property and comprises a layer having a reflective property thereunder; and

a color filter layer over the light-emitting element,

wherein color filter layers of pixels of different colors have different thicknesses, and

wherein each pixel is arranged so that a cavity effect is obtained.

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

wherein the layer having a reflective property is made of any metal selected from the consisting of silver, aluminum, molybdenum, copper, and chrome, an alloy of aluminum and titanium, or an alloy of silver and copper;

and/or

wherein the second electrode is made of any of indium tin oxide, indium zinc oxide, and graphene.

4. The light-emitting device according to claim 2, wherein the first electrode is a cathode of the light-emitting element, and the second electrode is an anode of the light-emitting element.

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

wherein the light-emitting element comprises:

a second light-emitting layer between the first electrode and the second electrode; and

a third light-emitting layer between the first electrode and the second electrode,

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

6. The light-emitting device according to claim 2, wherein the transistor comprises a channel formation region comprising an oxide semiconductor.

7. The light-emitting device according to claim 2, wherein the transistor comprises a channel formation region comprising indium and oxygen.

8. The light-emitting device according to claim 2, wherein an optical path length between the first electrode and the light-emitting layer is determined based on a central wavelength of a wavelength range where visible light passing through the color filter layer with a transmittance of 50% or higher.

9. The light-emitting device according to claim 2, wherein an optical path length between the first electrode and the light-emitting layer is one-quarter of a central wavelength of a wavelength range where visible light passing through the color filter layer with a transmittance of 50% or higher.

10. A light-emitting device comprising:

a first pixel comprises;

a first transistor;

a first light-emitting element over and electrically connected to the first transistor, the first light-emitting element comprising a light-emitting layer; and

a first color filter layer over the first light-emitting element,

a second pixel comprises;

a second transistor;

a second light-emitting element over and electrically connected to the second transistor, the second light-emitting element comprising the light-emitting layer; and

a second color filter layer over the second light-emitting element,

wherein a color of the first pixel differs from a color of the second pixel,

wherein a thickness of the first color filter layer differs from a thickness of the second color filter layer, and

wherein a distance between a top surface of the first color filter layer and a top surface of the light-emitting layer differs from a distance between a top surface of the second color filter layer and the top surface of the light-emitting layer.

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

wherein the first light-emitting element and the second light-emitting element comprise a second light-emitting layer and a third light-emitting layer, and

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

12. The light-emitting device according to claim 10, wherein the first transistor comprises a channel formation region comprising an oxide semiconductor.

13. The light-emitting device according to claim 10, wherein the first transistor comprises a channel formation region comprising indium and oxygen.

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

wherein the first light-emitting element comprises a first electrode having a reflective property under the light-emitting layer, and

wherein an optical path length between the first electrode and the light-emitting layer is determined based on a central wavelength of a wavelength range where visible light passing through the first color filter layer with a transmittance of 50% or higher.

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

wherein the first light-emitting element comprises a first electrode having a reflective property under the light-emitting layer, and

wherein an optical path length between the first electrode and the light-emitting layer is one-quarter of a central wavelength of a wavelength range where visible light passing through the first color filter layer with a transmittance of 50% or higher.