Achromatic design in the illumination system for a mini projector with LED light source

Abstract

We provide a novel achromatic design in the illumination system for a mini projector with an LED light source. The lateral color aberration at the corners of the DMD active area can be reduced to 0.48 mu m by our compact ATIR prism. The total prism size is 4091 mm(3). The spot sizes at the corner and the edge are also controlled under 198 mu m. Moreover, we use a light pipe for color uniformity at the center of the DMD active area. Under the two components for color uniformity, the Delta u' v' is well controlled under 0.016 by a 20 mm length of light pipe. The illuminance uniformity at the active area of the DMD chip is higher than 92.8%. The optical efficiency of the light pipe is 94.1%. (C) 2011 Optical Society of America