Douglas Allen Harrison

US Patent:

46601325, Apr 21, 1987

Filed:

Apr 3, 1986

Appl. No.:

6/847692

Inventors:

Bradley S. Basler - Redwood City CA
Douglas H. Harrison - Los Altos CA

Assignee:

Pindar Development Corporation - Sunnyvale CA

International Classification:

F21V 2900
F21V 914

US Classification:

362294

Abstract:

A cooling device for protecting a light absorbing optical element is provided. The cooling device includes an optical unit which comprises a transparent, thermally-conductive material disposed in heat conductive relation to the optical element. A mounting body supports the optical unit and receives heat energy therefrom. A heat pipe is mounted in the mounting body. Thus, heat energy is removed from the optical element and transferred to ambient through the thermally-conductive material, the mounting body and the heat pipe.

US Patent:

53749685, Dec 20, 1994

Filed:

Nov 8, 1993

Appl. No.:

8/148479

Inventors:

Duane A. Haven - Cupertino CA
David W. Vollmer - Santa Cruz CA
Douglas H. Harrison - Redwood City CA

Assignee:

Greyhawk Systems, Inc. - Mountain View CA

International Classification:

G03B 2100

US Classification:

353 31

Abstract:

A high-efficiency optical system for use in a liquid-crystal light-valve video projector. High intensity, unpolarized white light is separated into primary color components by color-selective filters transmitting light containing both first and second polarization states. Light of each primary color is characterized by a wavelength passband whereby the endpoints of the passband are defined by first and second wavelengths. The second passband endpoint of the first polarization state of the first primary color overlaps the first passband endpoint of the second polarization state of the second primary color, and the second passband endpoint of the second polarization state of the second primary color overlaps the first passband endpoint of the first polarization state of the third primary color. In addition, the video projector design utilizes low f/# optics in conjunction with absorptive polarizers to remove residual light of an unwanted polarization state allowed into the system by the low f/# optics. This allows high brightness with high efficiency and without sacrificing contrast.