PHOTONIC CRYSTAL PHOSPHOR LIGHT CONVERSION STRUCTURES FOR LIGHT EMITTING DEVICES

• US 20110215355A1
• Filed: 03/08/2010
• Published: 09/08/2011
• Est. Priority Date: 03/08/2010
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: van de Ven, Antony P., Negley, Gerald H.
• Granted Patent: US 9,991,427 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

Solid state light emitting devices include a solid state light emitting die and a photonic crystal phosphor light conversion structure. The photonic crystal phosphor light conversion structure may include a solid phosphor layer that includes dielectric nanostructures therein and may be on a light emitting surface of the solid state light emitting die. The photonic crystal phosphor light conversion structure may be attached to the light emitting surface of the solid state light emitting die via an adhesive layer. The photonic crystal phosphor light conversion structure may also be directly on a light emitting surface of the solid state light emitting die. Related methods are also disclosed.

Claims

1. A photonic crystal phosphor comprising a solid phosphor layer that comprises dielectric nanostructures therein.

2. The photonic crystal phosphor of claim 1, wherein the solid phosphor layer consists of a discrete single crystal phosphor.

3. The photonic crystal phosphor of claim 1, wherein the solid phosphor layer consists essentially of a discrete single crystal phosphor.

4. A solid state light emitting device comprising:

a primary solid state light emitting die that is configured to emit light upon energization thereof; and

a light conversion structure comprising a photonic crystal phosphor on a light emitting surface of the primary solid state light emitting die,

wherein the photonic crystal phosphor comprises a solid phosphor layer having dielectric nanostructures therein.

5. The solid state light emitting device of claim 4, wherein the dielectric nanostructures comprise holes within the solid phosphor layer.

6. The solid state light emitting device of claim 4, wherein the solid phosphor layer consists of a discrete single crystal phosphor.

7. The solid state light emitting device of claim 4, wherein the solid phosphor layer consists essentially of a discrete single crystal phosphor.

8. The solid state light emitting device of claim 4, further comprising an adhesive layer that attaches the light conversion structure to the light emitting surface.

9. The solid state light emitting device of claim 8, wherein the adhesive layer comprises silicone polymer.

10. The solid state light emitting device of claim 4, wherein the light conversion structure is sized to fit the light emitting surface of the primary solid state light emitting die.

11. The solid state light emitting device of claim 4, wherein the solid phosphor layer comprises cerium.

12. The solid state light emitting device of claim 11, wherein the solid phosphor layer comprises cerium at a concentration in a range of about 0.1 to about 20 weight percent.

13. The solid state light emitting device of claim 11, wherein the solid phosphor layer comprises Y₃Al₅O₁₂ doped with Ce³+(Ce:

YAG).

14. The solid state light emitting device of claim 11, wherein solid phosphor layer comprises Ca_xSr_yMg_1-x-yAlSiN₃ doped with cerium or strontium thio-gallate doped with cerium.

15. The solid state light emitting device of claim 4, wherein the solid phosphor layer comprises europium.

16. The solid state light emitting device of claim 15, wherein the solid phosphor layer comprises europium at a concentration in a range of about 0.5 to about 20 weight percent.

17. The solid state light emitting device of claim 15, wherein the solid phosphor layer comprises Sr_2-xBa_xSiO₄ doped with Eu²⁺ (BOSE).

18. The solid state light emitting device of claim 15, wherein the solid phosphor layer comprises a europium doped material, wherein the material is selected from the group consisting of Ca_xSr_1-xAlSiN₃, strontium thio-gallate, alpha-SiAlON, silicon garnet, Y₂O₂S and La₂O₂S.

19. The solid state light emitting device of claim 4, wherein a surface of the photonic crystal phosphor light conversion structure is texturized, roughened, etched and/or featured.

20. The solid state light emitting device of claim 4, wherein the light conversion structure is directly on the light emitting surface of the primary solid state light emitting die.

21. The solid state light emitting device of claim 4, wherein the light conversion structure acts as a substrate for the primary solid state light emitting die.

22. The solid state light emitting device of claim 4, wherein the solid phosphor layer has a thickness in a range of about 1 μ

m to about 200 μ

m.

23. The solid state light emitting device of claim 4, wherein the solid phosphor layer is spatially separated from the primary solid state light emitting die.

24. The solid state light emitting device of claim 4, further comprising one or more additional solid state light emitting dice configured to emit light upon energization thereof.

25. The solid state light emitting device of claim 24, wherein a first portion of the dielectric nanostructures are configured to interact with the primary solid state light emitting die and a second portion of the dielectric nanostructures are configured to interact with at least one of the additional solid state light emitting dice.

26. A method of fabricating a solid state light emitting device comprising:

placing a light conversion structure comprising a photonic crystal phosphor on a light emitting surface of a solid state light emitting die,

wherein the photonic crystal phosphor comprises a solid phosphor layer having dielectric nanostructures therein.

27. The method of claim 26, wherein placing the light conversion structure on the light emitting surface comprises adhesively attaching the light conversion structure to the light emitting surface of the solid state light emitting die.

28. The method of claim 26, wherein the dielectric nanostructures comprise holes within the solid phosphor layer.

29. A method of fabricating a solid state light emitting device comprising:

placing a light conversion structure comprising a solid phosphor layer on a light emitting surface of a solid state light emitting die, and

forming dielectric nanostructures in the solid phosphor layer.

30. The method of claim 29, wherein the dielectric nanostructures comprise holes in the solid phosphor layer.

31. The method of claim 29, wherein placing the light conversion structure on the light emitting surface comprises adhesively attaching the solid phosphor layer to the light emitting surface of the solid state light emitting die.

32. The method of claim 29, wherein placing the light conversion structure on the light emitting surface comprises growing a solid phosphor layer on the surface of the solid state light emitting die via a thin film deposition technique.

33. A method of fabricating a solid state light emitting device comprising

growing a solid state light emitting die on a surface of a light conversion structure that comprises a solid phosphor layer having dielectric nanostructures defined therein.

34. The method of claim 33, further comprising polishing the surface of the light conversion structure before the solid state light emitting die is grown thereon.