This invention provides a projector capable of effectively utilizing the light from the light source and significantly reducing the light illuminating the outside of the area to be illuminated, thereby attaining an excellent efficiency of light utilization. In the illuminating system of...http://www.google.fr/patents/US5749642?utm_source=gb-gplus-shareBrevet US5749642 - Illuminating optical system and projector utilizing the same
Illuminating optical system and projector utilizing the same