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Proceedings Paper

Metal halide lighting systems and optics for high-efficiency compact LCD projectors
Author(s): Benjamin A. Jacobson; Robert D. Gengelbach; Charles N. Stewart; Douglas M. Rutan
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Paper Abstract

Compact LCD projectors require a high efficiency light source that has the smallest possible spatial extent. Further, they require optical systems that preserve the etendue. Current projector illumination systems have aberrations that produce a light beam whose etendue far exceeds the intrinsic etendue of the light source itself. As a result both efficiency and uniformity fall short of what is theoretically possible. We provide a theoretical framework for understanding these aberrations and the magnitude of their effect. We also present results showing the efficiency, uniformity, and other performance gains which are possible when these aberrations are corrected. This work also describes the performance of long-life, short-arc metal halide lighting systems that are able to increase screen brightness of compact projectors several fold without any increase in system power or heat. With these systems it has been possible to design and validate lamps operating at 50 Watts, producing > 3,000 lumens and having excellent lumen maintenance throughout their 4,000 hour life. The benefits of the combination of an improved etendue-preserving optical system and a short-arc metal halide lamp will be demonstrated.

Paper Details

Date Published: 17 April 1998
PDF: 8 pages
Proc. SPIE 3296, Projection Displays IV, (17 April 1998); doi: 10.1117/12.305536
Show Author Affiliations
Benjamin A. Jacobson, Illumitech Inc. (United States)
Robert D. Gengelbach, Illumitech Inc. (United States)
Charles N. Stewart, Welch Allyn, Inc. (United States)
Douglas M. Rutan, Welch Allyn, Inc. (United States)

Published in SPIE Proceedings Vol. 3296:
Projection Displays IV
Ming Hsien Wu, Editor(s)

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