Hughes Aircraft Company

David D Scofield

Joseph Hubert Colles

Stephen J Reinsch

Paul F Robusto

John C Hamacher

Chan H Wang

Byung S Hong

Stephen J Purdy

A method for restricting the mode of operation of long wavelength waveguide laser (FIG. 1) by introducing an approximate step function into the reflectivity of circular optical elements (19) used in such lasers. The preferred method is to grind off a portion of the optical coating (20) of the optical element (19) leaving a circular unground region (26) of high reflectivity having a diameter (D) of approximately 60% of the laser bore width (b) bounded by a ground region (28) of lower reflectivity. The method permits simple, inexpensive field modification of existing lasers.

Method of altering reflectivity of optical elements

An improved optical block for use in a high brightness, full color image projection system of the type wherein high intensity (acrhomatic) projection light is modulated by a full color image composed of a plurality of monochromatic images applied to a plurality of polarization modulating light valves. A polarizer accepts the achromatic, unpolarized output of a high intensity source. Light of a preferred polarization orientation emergent therefrom is directed by the polarizer to a two level array of polarization-sensitive dichroic filters and wavelength-tuned biprisms. Input level dichroic filters separate the incoming unmodulated light into a plurality of component wavelength bands and direct each to a wavelength-tuned biprism. Each biprism directs the selected bandwidth of polarized light to the reflective surface of a light valve. Light reflected therefrom is altered in polarization in the presence of the chromatic component of the full color image and passes to the second or output level of the optical block. Polarization selective dichroic filters in the output level combine the polarization-modulated chromatic components into a high brightness, full color modulated image and direct the image to projection optics.

Optical block for high brightness full color video projection system

Growing community of inventors

San Diego, CA, United States of America

David D Scofield