Display device

• US 9,153,627 B2
• Filed: 03/02/2012
• Issued: 10/06/2015
• Est. Priority Date: 03/04/2011
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohsawa, Nobuharu, Sasaki, Toshiki, Seo, Satoshi
• Primary Examiner(s): Yang, Minchul
• Application Number:
  US13/410,799
• Publication Number:
  US 20120223346A1
• Time in Patent Office: 1,313 Days
• Field of Search: 257/40, 257/89, 257/79, 257/E33.072
• US Class Current: 1/1
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• 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 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/30 Devices specially adapted for multicolour light emission
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels
• 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 59/8052 Cathodes
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/622 containing four rings, e.g. pyrene
• CPC Class Codes: H10K 85/626 containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene
• CPC Class Codes: H10K 85/633 comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: H10K 85/6576 comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene

Abstract

To provide a display device with low power consumption. The display device includes a plurality of pixels each having a light-emitting element having a structure in which light emitted from a light-emitting layer is resonated between a reflective electrode and a light-transmitting electrode, wherein no color filter layers are provided or color filter layers with high transmittance are provided in pixels for light with relatively short wavelengths (e.g., pixels for blue and/or green), and a color filter layer is selectively provided in pixels for light with a long wavelength (e.g., pixels for red), and thereby maintaining color reproducibility and consuming less power.

Claims

1. A display device comprising:

a first substrate;

a first light-emitting element over the first substrate;

a second light-emitting element over the first substrate;

a third light-emitting element over the first substrate;

a first color filter layer having a transmission center wavelength in a green wavelength region, the first color filter layer overlaps with the second light-emitting element;

a second color filter layer having a transmission center wavelength in a red wavelength region, the second color filter layer overlaps with the third light-emitting element; and

a second substrate over the first light-emitting element, the second light-emitting element, and the third light-emitting element,

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises;

a reflective electrode;

a first light-emitting layer over the reflective electrode;

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

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

a light-transmitting electrode over the third light-emitting layer,

wherein emission colors of the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer are different from each other,

wherein a color filter layer overlapping with the first light-emitting element is not provided,

wherein a distance between the reflective electrode and the light-transmitting electrode of the first light-emitting element, a distance between the reflective electrode and the light-transmitting electrode of the second light-emitting element, and a distance between the reflective electrode and the light-transmitting electrode of the third light-emitting element are different from each other, and

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises a layer including an organic compound between the first light-emitting layer and the second light-emitting layer.

2. The display device according to claim 1,

wherein the second light-emitting element comprises a first light-transmitting conductive layer over the reflective electrode,

wherein the third light-emitting element comprises a second light-transmitting conductive layer over the reflective electrode, and

wherein a thickness of the first light-transmitting conductive layer and a thickness of the second light-transmitting conductive layer are different from each other.

3. The display device according to claim 1, wherein an area of the first light-emitting element is smaller than an area of the third light-emitting element.

4. The display device according to claim 1,

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises a layer including an organic compound between the reflective electrode and the light-transmitting electrode, and

wherein a thickness of the layer of the first light-emitting element, a thickness of the layer of the second light-emitting element, and a thickness of the layer of the third light-emitting element are different from each other.

5. The display device according to claim 1,

wherein the first color filter layer and the second color filter layer are positioned over the second substrate.

6. The display device according to claim 1, further comprising a metal plate and an adhesive layer between the first substrate and the metal plate.

7. The display device according to claim 1, wherein the first light-emitting layer, the second light-emitting layer, and the third-light emitting layer each comprise a phosphorescent compound.

8. A display device comprising:

a first substrate;

a first light-emitting element over the first substrate;

a second light-emitting element over the first substrate;

a third light-emitting element over the first substrate;

a first color filter layer having a transmission center wavelength in a green wavelength region, the first color filter layer overlaps with the second light-emitting element;

a second color filter layer having a transmission center wavelength in a red wavelength region, the second color filter layer overlaps with the third light-emitting element; and

a second substrate over the first light-emitting element and the second light-emitting element,

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises;

a reflective electrode;

a first light-emitting layer over the reflective electrode;

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

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

a light-transmitting electrode over the third light-emitting layer,

wherein emission colors of the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer are different from each other,

wherein a distance between the reflective electrode and the light-transmitting electrode of the first light-emitting element, a distance between the reflective electrode and the light-transmitting electrode of the second light-emitting element, and a distance between the reflective electrode and the light-transmitting electrode of the third light-emitting element are different from each other,

wherein a color filter layer overlapping with the first light-emitting element is not provided,

wherein the second color filter layer has a maximum transmittance in the red wavelength region higher than a maximum transmittance of the first color filter layer region in the green wavelength region, and

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises a layer including an organic compound between the first light-emitting layer and the second light-emitting layer.

9. The display device according to claim 8,

wherein the second light-emitting element comprises a first light-transmitting conductive layer over the reflective electrode,

wherein the third light-emitting element comprises a second light-transmitting conductive layer over the reflective electrode, and

wherein a thickness of the first light-transmitting conductive layer and a thickness of the second light-transmitting conductive layer are different from each other.

10. The display device according to claim 8, wherein an area of the first light-emitting element is smaller than an area of the third light-emitting element.

11. The display device according to claim 8,

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises a layer including an organic compound between the reflective electrode and the light-transmitting electrode, and

wherein a thickness of the layer of the first light-emitting element, a thickness of the layer of the second light-emitting element, and a thickness of the layer of the third light-emitting element are different from each other.

12. The display device according to claim 8,

wherein the first color filter layer and the second color filter layer are positioned over the second substrate.

13. The display device according to claim 8, further comprising a metal plate and an adhesive layer between the first substrate and the metal plate.

14. The display device according to claim 8, wherein the first light-emitting layer, the second light-emitting layer, and the third-light emitting layer each comprise a phosphorescent compound.

15. A display device comprising:

a first substrate;

a first light-emitting element over the first substrate;

a second light-emitting element over the first substrate;

a third light-emitting element over the first substrate;

a first color filter layer having a transmission center wavelength in a green wavelength region, the first color filter layer overlaps with the second light-emitting element;

a second color filter layer having a transmission center wavelength in a red wavelength region, the second color filter layer overlaps with the third light-emitting element; and

a second substrate over the first color filter layer and the second color filter layer,

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises;

a reflective electrode;

a first light-emitting layer over the reflective electrode;

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

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

a light-transmitting electrode over the third light-emitting layer,

wherein emission colors of the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer are different from each other,

wherein a distance between the reflective electrode and the light-transmitting electrode of the first light-emitting element, a distance between the reflective electrode and the light-transmitting electrode of the second light-emitting element, and a distance between the reflective electrode and the light-transmitting electrode of the third light-emitting element are different from each other,

wherein the first color filter layer has a maximum transmittance of 75% or more in the green wavelength region,

wherein a color filter layer overlapping with the first light-emitting element is not provided, and

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises a layer including an organic compound between the first light-emitting layer and the second light-emitting layer.

16. The display device according to claim 15, wherein the first color filter layer has a maximum transmission of 5% or more in a wavelength region of from 570 nm to 760 nm, inclusive.

17. The display device according to claim 15,

wherein the second light-emitting element comprises a first light-transmitting conductive layer over the reflective electrode,

wherein the third light-emitting element comprises a second light-transmitting conductive layer over the reflective electrode, and

wherein a thickness of the first light-transmitting conductive layer and a thickness of the second light-transmitting conductive layer are different from each other.

18. The display device according to claim 15, wherein an area of the first light-emitting element is smaller than an area of the third light-emitting element.

19. The display device according to claim 15,

wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises a layer including an organic compound between the reflective electrode and the light-transmitting electrode, and

wherein a thickness of the layer of the first light-emitting element, a thickness of the layer of the second light-emitting element, and a thickness of the layer of the third light-emitting element are different from each other.

20. The display device according to claim 15,

wherein the first color filter layer and the second color filter layer are positioned over the second substrate.

21. The display device according to claim 15, further comprising a metal plate and an adhesive layer between the first substrate and the metal plate.

22. The display device according to claim 15, wherein the first light-emitting layer, the second light-emitting layer, and the third-light emitting layer each comprise a phosphorescent compound.