Christopher W Lowery

US Patent:

6351069, Feb 26, 2002

Filed:

Feb 18, 1999

Appl. No.:

09/252207

Inventors:

Christopher H. Lowery - Fremont CA
Gerd Mueller - San Jose CA
Regina Mueller - San Jose CA

Assignee:

LumiLeds Lighting, U.S., LLC - San Jose CA

International Classification:

H05B 3314

US Classification:

313512, 313503, 313504, 313501

Abstract:

A light emitting device and a method of fabricating the device utilize a supplementary fluorescent material that radiates secondary light in the red spectral region of the visible light spectrum to increase the red color component of the composite output light. The secondary light from the supplementary fluorescent material allows the device to produce âwhiteâ output light that is well-balanced with respect to color for true color rendering applications. The supplementary fluorescent material is included in a fluorescent layer that is positioned between a die and a lens of the device. The die is preferably a GaN based die that emits light having a peak wavelength of 470 nm. The fluorescent layer also includes a main fluorescent material. Preferably, the main fluorescent material is Cerium (Ce) activated and Gadolinium (Gd) doped Yttrium Aluminum Garnet (YAG) phosphor (âCe:YAG phosphorâ). In a first preferred embodiment, the supplementary fluorescent material is a compound that is produced by doping the Ce:YAG phosphor with a trivalent ion of Praseodymium (Pr).

US Patent:

6504301, Jan 7, 2003

Filed:

Sep 3, 1999

Appl. No.:

09/390006

Inventors:

Christopher H. Lowery - Fremont CA

Assignee:

LumiLeds Lighting, U.S., LLC - San Jose CA

International Classification:

H01J 6304

US Classification:

313512, 362800

Abstract:

An LED package and a method of fabricating the LED package utilize a prefabricated fluorescent member that contains a fluorescent material that can be separately tested for optical properties before assembly to ensure the proper performance of the LED package with respect to the color of the output light. The LED package includes one or more LED dies that operate as the light source of the package. Preferably, the fluorescent material included in the prefabricated fluorescent member and the LED dies of the LED package are selectively chosen, so that output light generated by the LED package duplicates natural white light. In a first embodiment of the invention, the prefabricated fluorescent member is a substantially planar plate having a disk-like shape. In a second embodiment, the prefabricated fluorescent member is a non-planar disk that conforms to and is attached to the inner surface of a concave lens. In this embodiment, the optical properties of the fluorescent member are tested by examining an integrated unit formed by the concave lens and the attached fluorescent member.

US Patent:

6650044, Nov 18, 2003

Filed:

Oct 13, 2000

Appl. No.:

09/688053

Inventors:

Christopher H. Lowery - Fremont CA

Assignee:

Lumileds Lighting U.S., LLC - San Jose CA

International Classification:

H01J 162

US Classification:

313502, 313503, 313506, 313498, 313499

Abstract:

A method for forming a luminescent layer on a light emitting semiconductor device includes positioning a stencil on a substrate such that a light emitting semiconductor device disposed on the substrate is located within an opening in the stencil, depositing a stenciling composition including luminescent material in the opening, removing the stencil from the substrate, and curing the stenciling composition to a solid state. The resulting light emitting device includes a stack of layers including semiconductor layers comprising an active region and a luminescent material containing layer having a substantially uniform thickness disposed around at least a portion of the stack. A surface of the luminescent material containing layer not adjacent to the stack substantially conforms to a shape of the stack. In one embodiment, the light emitting device emits white light in a uniformly white spatial profile.

US Patent:

6686691, Feb 3, 2004

Filed:

Sep 27, 1999

Appl. No.:

09/405947

Inventors:

Gerd O Mueller - San Jose CA
Christopher H Lowery - Fremont CA

Assignee:

Lumileds Lighting, U.S., LLC - San Jose CA

International Classification:

H01J 162

US Classification:

313503, 313498, 313501, 25230165

Abstract:

The present invention relates to a tri-color lamp for generating white light. In particular, the invention relates to a phosphor mixture comprising two phosphors having host sulfide materials that can absorb radiation emitted by a light emitting diode, particularly a blue LED. This arrangement provides a mixing of three light sourcesâlight emitted from the two phosphors and unabsorbed light emitted from the LED. The phosphors can contain the same dopant, such as a rare earth ion, to allow matching of the phosphors in relation to the LED emitted radiation. Power fractions of each of the light sources can be varied to achieve good color rendering. The present invention also relates to an alternative to a green LED comprising a single green phosphor that absorbs radiation from a blue LED. A resulting device provides green light of high absorption efficiency and high luminous equivalent values.

US Patent:

6878973, Apr 12, 2005

Filed:

Aug 23, 2001

Appl. No.:

09/938407

Inventors:

Christopher Haydn Lowery - Fremont CA, US
Troy Trottier - San Jose CA, US

Assignee:

Lumileds Lighting U.S., LLC - San Jose CA

International Classification:

H01L033/00
H01L023/29

US Classification:

257100, 257 98, 257 99, 257789, 257795

Abstract:

A light emitting device and a method of making the same are provided. The light emitting device includes a light emitting diode and a submount. A phosphormaterial is disposed around at least a portion of the light emitting diode. An underfill is disposed between a first surface of the light emitting diode and a first surface of the submount. The underfill reduces contamination of the light emitting diode by the phosphor material.

US Patent:

7049159, May 23, 2006

Filed:

Nov 5, 2003

Appl. No.:

10/703040

Inventors:

Christopher H. Lowery - Fremont CA, US

Assignee:

Lumileds Lighting U.S., LLC - San Jose CA

International Classification:

H01L 21/00
H01L 21/40

US Classification:

438 22, 438 33, 438 82, 438 99

Abstract:

A method for forming a luminescent layer on a light emitting semiconductor device includes positioning a stencil on a substrate such that a light emitting semiconductor device disposed on the substrate is located within an opening in the stencil, depositing a stenciling composition including luminescent material in the opening, removing the stencil from the substrate, and curing the stenciling composition to a solid state. The resulting light emitting device includes a stack of layers including semiconductor layers comprising an active region and a luminescent material containing layer having a substantially uniform thickness disposed around at least a portion of the stack. A surface of the luminescent material containing layer not adjacent to the stack substantially conforms to a shape of the stack. In one embodiment, the light emitting device emits white light in a uniformly white spatial profile.

US Patent:

7053419, May 30, 2006

Filed:

Sep 12, 2000

Appl. No.:

09/660317

Inventors:

Michael D. Camras - Sunnyvale CA, US
Michael R. Krames - Mountain View CA, US
Wayne L. Snyder - Palo Alto CA, US
Frank M. Steranka - San Jose CA, US
Robert C. Taber - Palo Alto CA, US
John J. Uebbing - Palo Alto CA, US
Douglas W. Pocius - Sunnyvale CA, US
Troy A. Trottier - San Jose CA, US
Christopher H. Lowery - Fremont CA, US
Gerd O. Mueller - San Jose CA, US

Assignee:

LumiLeds Lighting U.S., LLC - San Jose CA

International Classification:

H01L 33/00

US Classification:

257 98

Abstract:

Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent lens having a refractive index for light emitted by the active region preferably greater than about 1. 5, more preferably greater than about 1. 8. A method of bonding a transparent lens to a light emitting device having a stack of layers including semiconductor layers comprising an active region includes elevating a temperature of the lens and the stack and applying a pressure to press the lens and the stack together. Bonding a high refractive index lens to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection. Advantageously, this improvement can be achieved without the use of an encapsulant.

US Patent:

7064355, Jun 20, 2006

Filed:

Jun 12, 2001

Appl. No.:

09/880204

Inventors:

Michael D. Camras - Sunnyvale CA, US
Michael R. Krames - Mountain View CA, US
Wayne L. Snyder - Palo Alto CA, US
Frank M. Steranka - San Jose CA, US
Robert C. Taber - Palo Alto CA, US
John J. Uebbing - Palo Alto CA, US
Douglas W. Pocius - Sunnyvale CA, US
Troy A. Trottier - San Jose CA, US
Christopher H. Lowery - Fremont CA, US
Gerd O. Mueller - San Jose CA, US
Gloria E. Hofler - Sunnyvale CA, US

Assignee:

Lumileds Lighting U.S., LLC - San Jose CA

International Classification:

H01L 33/00

US Classification:

257 98, 257 99, 257 94, 257 96, 257 81, 257680, 369112

Abstract:

Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent optical element having a refractive index for light emitted by the active region preferably greater than about 1. 5, more preferably greater than about 1. 8. A method of bonding a transparent optical element (e. g. , a lens or an optical concentrator) to a light emitting device comprising an active region includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection. Advantageously, this improvement can be achieved without the use of an encapsulant.