Patent ID: 8721083

Claim:
A polarization conversion system, comprising: a polarization beam splitter for receiving a non-polarized image light from a relay lens group, and splitting said non-polarized image light into a first-state first polarized beam and a second-state second polarized beam, wherein said first-state first polarized beam is propagated along a first optical path, and said second-state second polarized beam is propagated along a second optical path, wherein a total optical length of said first optical path is substantially equal to a total optical length of said second optical path; a polarization rotating element located in said second optical path for transforming said second-state second polarized beam into a first-state second polarized beam; and a polarization switch for receiving said first-state first polarized beam and said first-state second polarized beam, and selectively transforming said first-state first polarized beam and said first-state second polarized beam into a first output polarized beam and a second output polarized beam, so that said first output polarized beam and said second output polarized beam are alternately switched between said first state and said second state and respectively directed two identical projection lenses.