Patent ID: 8002412

Claim:
A projection system comprising: a light source module emitting a plurality of monochromic lights; at least one optical modulator modulating light emitted by the light source module according to a color signal, wherein the at least one optical modulator includes at least one semiconductor diode including a P type semiconductor layer, an N type semiconductor layer, and an intrinsic semiconductor layer located between the P and N type semiconductor layer, the intrinsic semiconductor layer of the at least one semiconductor diode absorbing or transmitting monochromic light from the light source module according to the value of a reverse bias voltage corresponding the color signal; a color combining prism combining the monochromic lights including light modulated by the optical modulator to form an image; and a projection lens projecting the image formed by the color combining prism toward a screen, wherein the optical modulator comprises a plurality of said semiconductor diodes arranged in units corresponding to pixels of the image, and a single semiconductor diode corresponds to a single pixel of the image.