Robert S Fletcher

US Patent:

6933535, Aug 23, 2005

Filed:

Oct 31, 2003

Appl. No.:

10/699433

Inventors:

Daniel A. Steigerwald - Cupertino CA, US
William D. Collins III - San Jose CA, US
Robert M. Fletcher - San Jose CA, US
Michael J. Ludowise - San Jose CA, US
Jason L. Posselt - San Jose CA, US

Assignee:

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

International Classification:

H01L033/00

US Classification:

257 89, 257 79, 257 94, 257 95, 257 98, 257 99, 257100, 257103, 313501, 313502, 313503

Abstract:

A structure includes semiconductor light emitting device and a wavelength converting layer. The wavelength converting layer converts a portion of the light emitted from the semiconductor light emitting device. The dominant wavelength of the combined light from the semiconductor light emitting device and the wavelength converting layer is essentially the same as the wavelength of light emitted from the device. The wavelength converting layer may emit light having a spectral luminous efficacy greater than the spectral luminous efficacy of the light emitted from the device. Thus, the structure has a higher luminous efficiency than a device without a wavelength converting layer.

US Patent:

50600281, Oct 22, 1991

Filed:

Jan 19, 1989

Appl. No.:

7/300003

Inventors:

Chih-Ping Kuo - Milpitas CA
Robert M. Fletcher - San Jose CA
Timothy D. Osentowski - San Jose CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H01L 3300

US Classification:

357 17

Abstract:

A high band-gap opto-electronic device is formed by epitaxially growing the device section in a lattice-matched (Al. sub. x Ga. sub. 1-x). sub. y In. sub. 1-y P-GaAs system. The band-gap of the epitaxial layer increases with x. Instead of growing the device section directly on the GaAs substrate, a layer of (Al. sub. x Ga. sub. 1-x). sub. y In. sub. 1-7 P, graded in x and in temperature while maintaining substantially y=0. 5, is grown as a transitional layer. The high band-gap device structures include homojunctions, heterojunctions and particularly a separate confinement quantum well heterostructures. Various embodiments of the invention include devices on absorbing substrates and on transparent substrates, and devices incorporating strained-layer superlattices.

US Patent:

52332047, Aug 3, 1993

Filed:

Jan 10, 1992

Appl. No.:

7/819542

Inventors:

Robert M. Fletcher - San Jose CA
Chihping Kuo - Milpitas CA
Jiann Yu - Palo Alto CA
Timothy D. Osentowski - San Jose CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H01L 3300

US Classification:

257 13

Abstract:

A light emitting diode (LED) including a light generation region situated on a light-absorbing substrate also includes a thick transparent layer which ensures that an increased amount of light is emitted from the sides of the LED and only a minimum amount of light is absorbed by the substrate. The thickness of the transparent layer is determined as a function of its width and the critical angle at which light is internally reflected within the transparent layer. The thick transparent layer is located either above, below or both above and below the light generation region. The thick transparent layer may be made of materials and with fabrication processes different from the light generation region.

US Patent:

52042847, Apr 20, 1993

Filed:

Aug 13, 1991

Appl. No.:

7/744569

Inventors:

Chih-Ping Kuo - Milpitas CA
Robert M. Fletcher - San Jose CA
Timothy D. Osentowski - San Jose CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H01L 2120
H01L 21203

US Classification:

437127

Abstract:

A high band-gap opto-electronic device is formed by epitaxially growing the device section in a lattice-matched (Al. sub. x Ga. sub. 1-x). sub. y In. sub. 1-y P-GaAs system. The band-gap of the epitaxial layer increases with x. Instead of growing the device section directly on the GaAs substrate, a layer of (Al. sub. x Ga. sub. 1-x). sub. y In. sub. 1-y P, graded in x and in temperature while maintaining substantially y=0. 5, is grown as a transitional layer. The high band-gap device structures include homojunctions, heterojunctions and particularly a separate confinement quantum well heterostructures. Various embodiments of the invention include devices on absorbing substrates and on transparent substrates, and devices incorporating strained-layer superlattices.

US Patent:

63072181, Oct 23, 2001

Filed:

Nov 20, 1998

Appl. No.:

9/196928

Inventors:

Daniel A. Steigerwald - Cupertino CA
Serge L Rudaz - Sunnyvale CA
Kyle J. Thomas - Sunnyvale CA
Steven D. Lester - Palo Alto CA
Paul S. Martin - Pleasanton CA
William R. Imler - Oakland CA
Robert M. Fletcher - San Jose CA
Fred A. Kish - San Jose CA
Steven A. Maranowski - San Jose CA

Assignee:

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

International Classification:

H01L 3300

US Classification:

257 99

Abstract:

A light emitting device includes a heterojunction having a p-type layer and an n-type layer. The n-electrode is electrically connected to the n-type layer while the p-electrode is electrically connected to the p-type layer. The p and n-electrodes are positioned to form a region having uniform light intensity.

US Patent:

50087185, Apr 16, 1991

Filed:

Dec 18, 1989

Appl. No.:

7/452800

Inventors:

Robert M. Fletcher - San Jose CA
Chihping Kuo - Milpitas CA
Timothy D. Osentowski - San Jose CA
Virginia M. Robbins - Mountain View CA

International Classification:

H01L 3300
H01S 319

US Classification:

357 17

Abstract:

A light-emitting diode has a semiconductor substrate underlying active p-n junction layers of AlGaInP for emitting light. A transparent window layer of semiconductor different from AlGaInP overlies the active layers and has a lower electrical resistivity than the active layers and a bandgap greater than the bandgap of the active layers, for minimizing current crowding from a metal electrical contact over the transparent window layer. The active layers may be epitaxially grown on a temporary GaAs substrate. A layer of lattice mismatched GaP is then grown on the active layers with the GaP having a bandgap greater than the bandgap of the active layers so that it is transparent to light emitted by the LED. The GaAs temporary substrate is then selectively etched away so that the GaP acts as a transparent substrate. A transparent window layer may be epitaxially grown over the active layers on the face previously adjacent to the GaAs substrate.