High efficiency organic light emitting device

• US 20080129191A1
• Filed: 06/28/2007
• Published: 06/05/2008
• Est. Priority Date: 12/04/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kim, Sang-Yeol, Kim, Mu-Gyeom, Lee, Sung-Hun, Ahn, Pil-Soo
• Granted Patent: US 7,750,564 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices

Abstract

Provided is an organic light emitting device (OLED) having increased optical extraction efficiency. The OLED includes a transparent substrate, an optical path control layer made of an optical transmittance material on the transparent substrate, a transparent electrode, an organic light emitting layer that generated light, and a reflection electrode formed on the organic light emitting layer, which are sequentially stacked. The refractive index And thickness of the optical path control layer are optimized.

Claims

1. An organic light emitting device comprising:

a transparent substrate;

a reflection electrode;

an organic light emitting layer formed between the transparent substrate and the reflection electrode, the organic light emitting layer emitting light;

a transparent electrode formed between the transparent substrate and the organic light emitting layer; and

an optical path control layer formed between the transparent substrate and the transparent electrode, the optical path control layer increasing emission of light.

2. The organic light emitting device of claim 1, comprised of the optical path control layer being made of a material having an optical transmittance no less than 90% in the visible light region.

3. The organic light emitting device of claim 1, wherein a difference between refractive indices of the optical path control layer and the transparent electrode is no greater than 10% in the visible light region.

4. The organic light emitting device of claim 1, comprised of the optical path control layer having a refractive index in a range from 1.6 to 2.4 in the visible light region.

5. The organic light emitting device of claim 1, comprised of the organic light emitting layer comprising a red color light emitting layer, a green color light emitting layer, and a blue color light emitting layer, wherein a white color being produced by mixing the lights emitted from the red color light layer, a green color light emitting layer, and a blue color light emitting layer.

6. The organic light emitting device of claim 1, wherein a sum of thicknesses of the transparent electrode and the optical path control layer ranges from about 400 nm to about 900 nm.

7. The organic light emitting device of claim 1, comprised of the organic light emitting layer comprising at least two light emitting layers, one of which generates a first color, and another of which generates a second color that is a complementary color of the first color.

8. The organic light emitting device of claim 7, wherein the sum of thicknesses of the transparent electrode and the optical path control layer ranges from about 400 nm to about 900 nm.

9. The organic light emitting device of claim 1, wherein the organic light emitting layer comprises a light emitting layer that generates a single color.

10. The organic light emitting device of claim 1, wherein the optical path control layer is made of a material selected from the group consisting of an organic material, an oxide material, a nitride material, a sulfide material, and combinations thereof.

11. The organic light emitting device of claim 10, wherein the optical path control layer is made of a material selected from the group consisting of Al₂O₃, BaO, MgO, HfO₂, ZrO₂, CaO₂, SrO₂, Y₂O₃, Si₃N₄, AlN, GaN, ZnS, CdS, and combinations thereof.

12. An organic light emitting device comprising:

a substrate;

an optical path control layer for increasing emission of light;

a reflection electrode formed between the substrate and the optical path control layer;

an organic light emitting layer formed between the reflection electrode and the optical path control layer, the organic light emitting layer emitting light; and

a transparent electrode formed between the organic light emitting layer and the optical path control layer.

13. The organic light emitting device of claim 12, comprised of the optical path control layer being made of a material having an optical transmittance no less than 90% in the visible light region.

14. The organic light emitting device of claim 12, wherein a difference between refractive indices of the optical path control layer and the transparent electrode is no greater than 10% in the visible light region.

15. The organic light emitting device of claim 12, comprised of the optical path control layer having a refractive index in a range from 1.6 to 2.4 in the visible light region.

16. The organic light emitting device of claim 12, comprised of the organic light emitting layer comprising a red color light emitting layer, a green color light emitting layer, and a blue color light emitting layer, wherein a white color being produced by mixing the lights emitted from the red color light layer, a green color light emitting layer, and a blue color light emitting layer.

17. The organic light emitting device of claim 12, comprised of the organic light emitting layer comprising at least two light emitting layers, one of which generates a first color, and another of which generates a second color that is a complementary color of the first color.

18. The organic light emitting device of claim 12, wherein the organic light emitting layer comprises a light emitting layer that generates a single color.

19. The organic light emitting device of claim 12, wherein the optical path control layer is made of a material selected from the group consisting of an organic material, an oxide material, a nitride material, a sulfide material, and combinations thereof.

20. The organic light emitting device of claim 19, wherein the optical path control layer is made of a material selected from the group consisting of Al₂O₃, BaO, MgO, HfO₂, ZrO₂, CaO₂, SrO₂, Y₂O₃, Si₃N₄, AlN, GaN, ZnS, CdS, and combinations thereof.