Patent ID: 7529024

Claim:
A polarization conversion system for converting at least one non-polarized first light beam and a non-polarized second light beam into a polarized beam, comprising: at least one beam splitting and combining unit, comprising: a polarization beam splitting element for reflecting a first portion beam of the first light beam and allowing a second portion beam of the first light beam to pass through; and a dichroic element, disposed substantially in parallel to the polarization beam splitting element and allowing the first light beam to pass through; and a dichroic unit, disposed at a side of the beam splitting and combining unit for reflecting the first portion beam of the first light beam; and a polarization beam splitting unit, disposed at another side of the beam splitting and combining unit for reflecting a third portion beam of the second light beam and allowing a fourth portion beam of the second light beam to pass through, wherein the third portion beam from the polarization beam splitting unit is reflected by the dichroic element; a first half wave plate, disposed between the beam splitting and combining unit and the polarization beam splitting unit for converting the polarization of the third portion beam of the second light beam; and a second half wave plate, disposed between the beam splitting and combining unit and the dichroic unit for converting the polarization of the first portion beam of the first light beam, wherein the first portion beam, the second portion beam, the third portion beam and the fourth portion beam passing through the polarization conversion system form the polarized beam.