Light emitting devices with improved light extraction efficiency

• US 7,276,737 B2
• Filed: 01/09/2006
• Issued: 10/02/2007
• Est. Priority Date: 07/31/2003
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Inventors: Harbers, Gerard, Martin, Paul S., Steranka, Frank M., Camras, Michael D., Imler, William R., Tichy, Ladislav, Ticha, Helena, Pocius, Douglas W., Keuper, Matthijs H., West, R. Scott
• Primary Examiner(s): TRAN, MINH LOAN
• Application Number:
  US11/328,964
• Publication Number:
  US 20060118805A1
• Time in Patent Office: 631 Days
• Field of Search: 257 98-100, 257/E33.058, 257/E33.037, 257/E33.073, 257/E33.071
• US Class Current: 257/98
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• 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
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A device includes a light emitting semiconductor device bonded to an optical element. In some embodiments, the optical element may be elongated or shaped to direct a portion of light emitted by the active region in a direction substantially perpendicular to a central axis of the semiconductor light emitting device and the optical element. In some embodiments, the semiconductor light emitting device and optical element are positioned in a reflector or adjacent to a light guide. The optical element may be bonded to the first semiconductor light emitting device by a bond at an interface disposed between the optical element and the semiconductor light emitting device. In some embodiments, the bond is substantially free of organic-based adhesives.

Claims

1. A device comprising:

a semiconductor light emitting device comprising a stack of semiconductor layers including an active region;

an optical element bonded to the semiconductor light emitting device; and

a bonding layer disposed between the optical element and the semiconductor light emitting device;

wherein the bonding layer comprises an oxide of tellurium.

2. The device of claim 1 wherein the semiconductor light emitting device comprises one of a substrate and a superstrate.

3. The device of claim 2 wherein the one of a substrate and a superstrate comprises a material selected from the group of sapphire, SiC, aluminum oxynitride, zirconia oxide, GaN, AlN, spinel, GaP, ZnS, an oxide of tellurium, an oxide of lead, an oxide of tungsten, and transparent alumina.

4. The device of claim 1 further comprising a plurality of grooves formed on the optical element.

5. The device of claim 1 wherein the optical element comprises a Fresnel lens.

6. The device of claim 1 further comprising a Fresnel lens formed on the optical element.

7. The device of claim 1 further comprising a reflective material formed on at least a portion of the optical element.

8. The device of claim 1 wherein the bonding layer has a softening temperature between about 250°

C. and about 500°

C.

9. The device of claim 1 wherein the shape of the optical element is one of a dome, a paraboloid, a cone-shape, and a beveled shape.

10. The device of claim 1 wherein the optical element comprises one or more luminescent materials, capable of converting a wavelength of light emitted by the stack of layers to at least another wavelength.

11. The device of claim 1 wherein a portion of the optical element is coated with one or more luminescent materials, capable of converting a wavelength of light emitted by the stack of layers to at least another wavelength.

12. The device of claim 1 wherein the bonding layer comprises one or more luminescent materials, capable of converting a wavelength of light emitted by the stack of layers to at least another wavelength.

13. The device of claim 1 wherein at least one surface of the stack of layers is beveled.

14. The device of claim 1 wherein a bottom surface of the optical element is substantially parallel to a growth direction of the stack of layers.

15. The device of claim 1 wherein a bottom surface of the optical element is substantially perpendicular to a growth direction of the stack of layers.

16. The device of claim 1 wherein the semiconductor light emitting device is bonded to the optical element in a flip chip orientation.

17. The device of claim 1 wherein the optical element comprises a material selected from the group of sapphire, SiC, aluminum oxynitride, zirconia oxide, GaN, AlN, spinel, GaP, ZnS, an oxide of tellurium, an oxide of lead, an oxide of tungsten, and transparent alumina.