LEDS WITH IMPROVED LIGHT EXTRACTION

• US 20150084005A1
• Filed: 09/23/2013
• Published: 03/26/2015
• Est. Priority Date: 09/23/2013
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Liu, Jie Jerry, Shi, Xiaolei, Shiang, Joseph John, Janora, Kevin Henry, Sista, Srinivas Prasad
• Application Number:
  US14/034,151
• Publication Number:
  US 20150084005A1
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: H10K 2102/331 Nanoparticles used in non-emissive layers, e.g. in packaging layer
• CPC Class Codes: H10K 50/854 comprising scattering means

Abstract

A light extraction structure that includes a composition of a base material and a scattering material disposed within the base material. The scattering material is a metal oxide, and the difference between the refractive indices of the base material and the scattering material is at least +/−0.05.

Claims

1. A light extraction structure comprising:

a base material with a first refractive index; and

a scattering material with a second refractive index disposed within the base material, wherein the scattering material is a metal oxide;

wherein the difference between the first and second refractive indices is at least +/−

0.05.

2. The light extraction structure of claim 1, wherein the light extraction structure comprises an organic light emitting diode (OLED).

3. The light extraction structure of claim 2, wherein the base material has solvent resistant properties to organic solvents.

4. The light extraction structure of claim 1, wherein the scattering material comprises particles ranging in size from 0.5 μ

m to 5 μ

m.

5. The light extraction structure of claim 1, wherein the base material is a glass material with a low melting point.

6. The light extraction structure of claim 1, wherein the base material is a polymer.

7. The light extraction structure of claim 1, comprising a semiconductor material, wherein the first refractive index of the base material matches a refractive index of the semiconductor material.

8. The light extraction structure of claim 1, comprising a semiconductor material, wherein the first refractive index of the base material is less than a refractive index of the semiconductor material.

9. The light extraction structure of claim 8, wherein nanoparticles with a third refractive index are dispersed uniformly within the base material.

10. The light extraction structure of claim 9, wherein the nanoparticles comprise a metal oxide and range in size from 2 nm to 20 nm.

11. The light extraction structure of claim 9, wherein the base material is a glass material, and the third refractive index of the nanoparticles is greater than the first refractive index of the base material by at least 0.1.

12. The light extraction structure of claim 9, wherein the base material is a polymer, and the third refractive index of the nanoparticles is greater than the first refractive index of the base material by at least 0.3.

13. The light extraction structure of claim 1, wherein the light extraction structure is planarized.

14. A light extraction structure comprising:

a first layer comprising a base material with a first refractive index and a scattering material with a second refractive index disposed within the base material; and

a planarization layer with a third refractive index disposed directly over the base material.

15. The light extraction structure of claim 14, wherein the scattering material comprises a metal oxide.

16. The light extraction structure of claim 14, wherein the light extraction structure comprises an OLED.

17. The light extraction structure of claim 16, wherein the base material and the planarization layer have solvent resistant properties to organic solvents.

18. The light extraction structure of claim 14, wherein the planarization layer has a transparency of at least 90%, a haze of less than 5%, or both.

19. The light extraction structure of claim 14, wherein the planarization layer is a glass material.

20. The light extraction structure of claim 14, wherein the planarization layer is an ultraviolet curable polymer or monomer.

21. The light extraction structure of claim 14, comprising a semiconductor material, wherein the third refractive index of the planarization layer matches that of the semiconductor material.

22. The light extraction structure of claim 14, comprising a semiconductor material, wherein the third refractive index of the planarization layer is less than that of the semiconductor material.

23. The light extraction structure of claim 22, wherein nanoparticles with a fourth refractive index are dispersed uniformly within the planarization layer.

24. The light extraction structure of claim 23, wherein the nanoparticles comprise a metal oxide and range in size from 2 nm to 20 nm.

25. The light extraction structure of claim 23, wherein the planarization layer is a glass material, and the fourth refractive index of the nanoparticles is greater than the third refractive index of the planarization layer by at least 0.3.

26. The light extraction structure of claim 23, wherein the planarization layer is a polymer or monomer, and the fourth refractive index of the nanoparticles is greater than the third refractive index of the planarization layer by at least 0.1.

27. The light extraction structure of claim 14, wherein the first layer is textured with micro lenses or micro cones with dimensions less than 10 μ

m.

28. A light emitting diode (LED) comprising:

a substrate;

a light extraction structure disposed directly over the substrate and comprising a first layer comprising a base material and a scattering material, wherein the scattering material comprises a metal oxide;

a first electrode disposed over the light extraction structure;

a plurality of layers of semiconductor materials disposed over the first electrode;

and

a second electrode disposed over the layers of semiconductor materials, wherein the light extraction structure is configured to reduce the amount of total internal reflection that occurs within the semiconductor materials.

29. The LED of claim 28, wherein the LED is an OLED.

30. The LED of claim 28, wherein the light extraction structure comprises a planarization layer.

31. The LED of claim 28, wherein the refractive indices of each successive layer decreases when moving from the layers of semiconductor materials to the first electrode.

32. The LED of claim 28, wherein the first electrode comprises a transparent anode and the second electrode comprises a cathode.

33. The LED of claim 28, wherein the first electrode comprises a transparent cathode and the second electrode comprises an anode.