An LED multiplexer with improved efficiency

Joshua Cobb

doi:10.1117/12.801757

23 September 2008 An LED multiplexer with improved efficiency

Joshua Cobb

Proceedings Volume 7103, Illumination Optics; 710308 (2008) https://doi.org/10.1117/12.801757
Event: Optical Systems Design, 2008, Glasgow, Scotland, United Kingdom

Abstract

Light emitting diodes (LED) have been increasingly used as light sources for projection display. LEDs have numerous advantages as a light source for these applications especially when used with a digital micro-mirror spatial light modulator such as the device offered by Texas Instruments. LEDs create an expanded color gamut, they can be modulated at very high rates (thus, eliminating the need for a color wheel), and they last longer than other light sources. One disadvantage they have is the luminous output is lower than would be desired for most front projection applications. Smaller pocket projectors have used the LED sources successfully, but the luminous output is limited to between 25 and 100 lumens. One of the areas of light loss in the illumination system is in the multiplexer that combines the three colored LEDs into a coaxial illumination beam. In this paper, this loss is quantified and an alternate multiplexer design is proposed.

Citation Download Citation

Joshua Cobb "An LED multiplexer with improved efficiency", Proc. SPIE 7103, Illumination Optics, 710308 (23 September 2008); https://doi.org/10.1117/12.801757

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