Patent ID: 6402323
Filing Date: 2002-06-11
Classification: G03B

Abstract:
A reflective type liquid crystal projection system comprising:an incident light source for generating a parallel light beam, said parallel light beam having first, second and third primary color frequencies and being s-polarized; a first frequency dependent beam splitter reflecting said first primary color frequency light and transmitting said second and third primary color frequency light beams; a first mirror for directing said second and third primary color frequency light beams through an s-polarizing plate for polarization filtering; a second mirror for directing said first primary color frequency light through a first retarder plate and a p-polarizing plate, said first retarder plate converting said first primary color frequency light to p-polarized light, said p-polarizing plate filtering said p-polarized first primary color frequency light; a second frequency dependent beam splitter reflecting said second primary color frequency light and transmitting said first and third primary color frequency light beams, said first and second primary color frequency light beams being received by a two-color polarizing beam splitter, said two-color polarizing beam splitter converting said second primary color frequency light to p-polarization and said first primary color frequency light to s-polarization, said third primary color frequency light beam being received by a single-color polarizing beam splitter, said single-color polarizing beam splitter converting said s-polarized third primary color frequency light to p-polarization and transmitting said p-polarized third primary color frequency light through a p-polarization filter and then through a second retarder plate, converting said third primary color frequency light back to s-polarization, said third primary color frequency light beam being received by a single-color polarizing beam splitter, said single-color polarizing beam splitter converting said s-polarized third primary color frequency light to p-polarization and transmitting said p-polarized third primary color frequency light through a p-polarization filter and then through s-polarized first and third primary color frequency light beams being recombined with said p-polarized second primary color frequency light beam.