Phosphor based light sources having a non-planar short pass reflector and method of making

• US 20040145289A1
• Filed: 12/02/2003
• Published: 07/29/2004
• Est. Priority Date: 01/27/2003
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Wheatley, John A., Weber, Michael F., Ouderkirk, Andrew J.
• Application Number:
  US10/726,968
• Publication Number:
  US 20040145289A1
• Time in Patent Office: Days
• US Class Current: 313/113
• CPC Class Codes: H01J 1/70 with protective, conductive, or reflective layers
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body

Abstract

A light source includes an LED that emits excitation light, a layer of phosphor material positioned to receive the excitation light, the phosphor material emitting visible light when illuminated with the excitation light, and a non-planar flexible multilayer reflector that transmits the excitation light and reflects visible light. The non-planar flexible multilayer reflector is positioned between the LED and the layer of phosphor material.

Claims

1. A light source, comprising:

an LED that emits excitation light;

a layer of phosphor material positioned to receive the excitation light, the phosphor material emitting visible light when illuminated with the excitation light; and

a non-planar flexible multilayer reflector that transmits the excitation light and reflects visible light, the non-planar flexible multilayer reflector being positioned between the LED and the layer of phosphor material.

2. The light source according to claim 1, wherein the non-planar flexible multilayer reflector comprises polymeric material.

3. The light source according to claim 1, wherein the non-planar flexible multilayer reflector comprises alternating layers of a first and second thermoplastic polymer and wherein at least some of the layers are birefringent.

4. The light source according to claim 1, wherein the excitation light comprises UV light.

5. The light source according to claim 1, wherein the non-planar flexible multilayer reflector is a concave polymeric multilayer reflector.

6. The light source according to claim 1, wherein the non-planar flexible multilayer reflector is a hemispherical concave polymeric multilayer reflector.

7. The light source according to claim 1, wherein the layer of phosphor material is disposed on the non-planar flexible multilayer reflector.

8. The light source according to claim 1, wherein the non-planar flexible multilayer reflector comprises a polymeric material that resists degradation when exposed to U.V. light.

9. The light source according to claim 2, wherein the non-planar polymeric multilayer reflector is a polymeric material substantially free of inorganic materials.

10. The light source according to claim 1, wherein the layer of phosphor material is a discontinuous layer of phosphor material.

11. The light source according to claim 1, wherein the layer of phosphor material is a plurality of dots of phosphor material.

12. The light source according to claim 11, wherein each dot has an area of less than 10000 micron².

13. The light source according to claim 11, wherein the plurality of dots comprise phosphor material that emit red, green and blue light when illuminated with excitation light.

14. The light source according to claim 11, wherein at least a first phosphor dot emits light at a first wavelength and a second phosphor dot emits light at a second wavelength different than the first wavelength.

15. A method of manufacturing a light source, comprising the steps of:

providing a LED that emits excitation light;

positioning a layer of phosphor material such that the phosphor material emits visible light when illuminated with the excitation light; and

positioning a non-planar flexible multilayer reflector that transmits the excitation light onto the phosphor material and reflects visible light.

16. The method according to claim 15, wherein the positioning a non-planar flexible multilayer reflector further comprises shaping a flexible multilayer reflector to form a non-planar flexible multilayer reflector.

17. The method according to claim 15, further comprising thermoforming a polymeric multilayer reflector to form a non-planar flexible multilayer reflector.