Phosphor based light sources having a reflective polarizer

• US 20040150997A1
• Filed: 01/20/2004
• Published: 08/05/2004
• Est. Priority Date: 01/27/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ouderkirk, Andrew J., Weber, Michael F.
• Granted Patent: US 7,091,661 B2
• Time in Patent Office: Days
• US Class Current: 362/255
• 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 2924/01077 Iridium [Ir]
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• 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 33/505 characterised by the shape, e.g. plate or foil

Abstract

A LED package includes an LED that emits excitation light and an optically transparent body. A layer of phosphor material is positioned to receive the excitation light and is disposed on or in the optically transparent body. The phosphor material emits visible light when illuminated with the excitation light. A reflective polarizer layer is disposed on or in the optically transparent body and is positioned to receive the emitted visible light.

Claims

1. An LED package, comprising:

an LED that emits excitation light;

an optically transparent body;

a layer of phosphor material positioned to receive the excitation light and disposed on or in the optically transparent body, the phosphor material emitting visible light when illuminated with the excitation light; and

a reflective polarizer layer disposed on or in the optically transparent body positioned to receive the emitted visible light.

2. The LED package according to claim 1, wherein the LED is disposed within the optically transparent body.

3. The LED package according to claim 1, wherein the LED is disposed adjacent to the optically transparent body.

4. The LED package according to claim 1, wherein the reflective polarizer layer is disposed on the optically transparent body.

5. The LED package according to claim 1, wherein the reflective polarizer layer is disposed in the optically transparent body.

6. The LED package according to claim 1, further comprising a short pass reflector disposed between the LED and the layer of phosphor material.

7. The LED package according to claim 1, further comprising a long pass reflector disposed between the layer of phosphor material and the reflective polarizer.

8. The LED package according to claim 1, further comprising a short pass reflector disposed between the LED and the layer of phosphor material and a long pass reflector disposed between the layer of phosphor material and the reflective polarizer.

9. The LED package according to claim 6, wherein the short pass reflector comprises polymeric material.

10. The LED package according to claim 7, wherein the long pass reflector comprises polymeric material.

11. The LED package according to claim 6, wherein the short pass reflector is a non-planar short pass reflector.

12. The LED package according to claim 7, wherein the long pass reflector is a non-planar long pass reflector.

13. The LED package according to claim 1, wherein the reflective polarizer comprises cholesteric material.

14. The LED package according to claim 1, wherein the reflective polarizer comprises a multilayer polymeric material.

15. The LED package according to claim 1, wherein the reflective polarizer comprises a multilayer birefringent polymeric material.