Patent ID: 7532261

Claim:
A projection system comprising: a light source unit for emitting polarized light with a first polarization direction along an axis; a liquid crystal panel; a projection lens; the liquid crystal panel and the projection lens being set along the axis associated with the polarized light; a polarization direction rotating member interposed between the light source unit and the liquid crystal panel, the polarization direction rotating member having a solid body and a through hole defined in the solid body, the polarized light having a first portion incident on the solid body of the polarization direction rotating member and a second portion passing through the through hole thereof, the polarization direction rotating member being configured for rotating the first polarization direction of the first portion of the polarized light to a second polarization direction and allowing the second portion of the polarized light to pass therethrough with the polarization direction thereof kept unchanged; and a polarization direction polarization direction restoration polarizer interposed between the polarization direction rotating member and the liquid crystal panel, the polarization direction polarization direction restoration polarizer being configured for changing the second polarization direction of the first portion of the polarized light transmitting therethrough to the first polarization direction.