Semiconductor light emitting devices with densely packed phosphor layer at light emitting surface

• US 8,410,679 B2
• Filed: 09/21/2010
• Issued: 04/02/2013
• Est. Priority Date: 09/21/2010
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Ibbetson, James, Andrews, Peter S.
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Breval, Elmito
• Application Number:
  US12/887,097
• Publication Number:
  US 20120068594A1
• Time in Patent Office: 924 Days
• Field of Search: 313495-512, 257/98, 257/E33.06, 257/E21.211
• US Class Current: 313/501
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources

Abstract

An LED includes a chip having a light emitting surface, and a coating of phosphor-containing material on the light emitting surface. Phosphor particles are arranged in a densely packed layer within the coating at the light emitting surface, and such that the light emitting surface is in contacting relationship with the phosphor particles.

Claims

1. A semiconductor light emitting device, comprising:

a semiconductor light emitting element having a light emitting surface; and

a coating of phosphor-containing material on the light emitting surface, wherein phosphor particles are arranged in a densely packed layer within the coating at the light emitting surface, and such that the light emitting surface is in contacting relationship with the densely packed layer of phosphor particles, and wherein the densely packed layer of phosphor particles does not extend all the way through the coating.

2. The semiconductor light emitting device of claim 1, wherein an average distance that heat generated by the phosphor particles travels from the densely packed layer to the semiconductor light emitting element is substantially less than half the thickness of the coating.

3. The semiconductor light emitting device of claim 1, wherein the light emitting surface comprises a pattern of features extending outwardly to form receptacles for receiving the phosphor particles.

4. The semiconductor light emitting device of claim 1, wherein the light emitting surface emits light having a first dominant wavelength upon the application of a voltage to the semiconductor light emitting element, and wherein the phosphor particles convert light emitted by the light emitting surface to light having a second dominant wavelength different from the first dominant wavelength.

5. The semiconductor light emitting device of claim 1, wherein the semiconductor light emitting element is selected from the group consisting of light emitting diodes and laser diodes.

6. The semiconductor light emitting device of claim 1, wherein the coating of phosphor-containing material comprises silicone or silicon.

7. A lighting device, comprising:

a semiconductor light emitting element that emits light having a first dominant wavelength upon the application of a voltage thereto; and

a coating of phosphor-containing material on a light emitting surface of the element, wherein phosphor particles are arranged in a densely packed layer within the material at the light emitting surface, and such that the light emitting surface is in contacting relationship with the densely packed layer of phosphor particles, wherein the phosphor particles convert light emitted by the light emitting surface to light having a second dominant wavelength different from the first dominant wavelength, and wherein the densely packed layer of phosphor particles does not extend all the way through the coating.

8. The lighting device of claim 7, wherein the light emitting surface comprises a pattern of features extending outward from the light emitting surface that form receptacles for receiving the phosphor particles.

9. A semiconductor light emitting device, comprising:

a semiconductor light emitting element having a light emitting surface;

an element in adjacent, spaced-apart relationship with the light emitting surface; and

a coating of phosphor-containing material on the element, wherein phosphor particles are arranged in a densely packed layer within the coating.

10. The semiconductor light emitting device of claim 9, wherein the element comprises a lens.

11. The semiconductor light emitting device of claim 9, wherein the element comprises a reflective element.

12. A semiconductor light emitting device, comprising:

a semiconductor light emitting element having a light emitting surface wherein the light emitting surface comprises a pattern of features extending outwardly to form receptacles; and

a coating of phosphor-containing material on the light emitting surface, wherein phosphor particles are arranged in a densely packed layer within the coating at the light emitting surface, and such that phosphor particles in the densely packed layer are received within the light emitting surface receptacles, and wherein the densely packed layer of phosphor particles does not extend all the way through the coating.

13. The semiconductor light emitting device of claim 12, wherein an average distance that heat generated by the phosphor particles travels from the densely packed layer to the semiconductor light emitting element is substantially less than half the thickness of the coating.

14. The semiconductor light emitting device of claim 12, wherein the light emitting surface emits light having a first dominant wavelength upon the application of a voltage to the semiconductor light emitting element, and wherein the phosphor particles convert light emitted by the light emitting surface to light having a second dominant wavelength different from the first dominant wavelength.

15. The semiconductor light emitting device of claim 12, wherein the semiconductor light emitting element is selected from the group consisting of light emitting diodes and laser diodes.

16. The semiconductor light emitting device of claim 12, wherein the coating of phosphor-containing material comprises silicone or silicon.

17. A semiconductor light emitting device, comprising:

a semiconductor light emitting element having a light emitting surface;

an intermediate layer of material on the light emitting surface, wherein the intermediate layer of material comprises a pattern of features extending outwardly therefrom to form receptacles for receiving phosphor particles; and

a coating of phosphor-containing material on the intermediate layer of material, wherein phosphor particles are arranged in a densely packed layer within the coating at the intermediate layer of material and such that phosphor particles in the densely packed layer are received within the receptacles, and wherein the densely packed layer of phosphor particles does not extend all the way through the coating.

18. The semiconductor light emitting device of claim 17, wherein an average distance that heat generated by the phosphor particles travels from the densely packed layer to the semiconductor light emitting element is substantially less than half the thickness of the coating.

19. The semiconductor light emitting device of claim 17, wherein the light emitting surface emits light having a first dominant wavelength upon the application of a voltage to the semiconductor light emitting element, and wherein the phosphor particles convert light emitted by the light emitting surface to light having a second dominant wavelength different from the first dominant wavelength.

20. The semiconductor light emitting device of claim 17, wherein the semiconductor light emitting element is selected from the group consisting of light emitting diodes and laser diodes.

21. The semiconductor light emitting device of claim 17, wherein the coating of phosphor-containing material comprises silicone or silicon.

22. A lighting device, comprising:

a semiconductor light emitting element that emits light having a first dominant wavelength upon the application of a voltage thereto;

an intermediate layer of material on the light emitting element, wherein the intermediate layer of material comprises a pattern of features extending outwardly therefrom to form receptacles for receiving phosphor particles; and

a coating of phosphor-containing material on the intermediate layer of material, wherein phosphor particles are arranged in a densely packed layer within the coating at the intermediate layer of material and such that phosphor particles in the densely packed layer are received within the receptacles, wherein the phosphor particles convert light emitted by the light emitting element to light having a second dominant wavelength different from the first dominant wavelength, and wherein the densely packed layer of phosphor particles does not extend all the way through the coating.

23. The semiconductor light emitting device of claim 22, wherein an average distance that heat generated by the phosphor particles travels from the densely packed layer to the semiconductor light emitting element is substantially less than half the thickness of the coating.

24. The semiconductor light emitting device of claim 22, wherein the light emitting surface emits light having a first dominant wavelength upon the application of a voltage to the semiconductor light emitting element, and wherein the phosphor particles convert light emitted by the light emitting surface to light having a second dominant wavelength different from the first dominant wavelength.

25. The semiconductor light emitting device of claim 22, wherein the semiconductor light emitting element is selected from the group consisting of light emitting diodes and laser diodes.

26. The semiconductor light emitting device of claim 22, wherein the coating of phosphor-containing material comprises silicone or silicon.