Patent ID: 7038852
Filing Date: 2006-05-02
Classification: G02B

Abstract:
1. A polarization conversion optical system for converting light having a nonuniform plane of polarization to light having a uniform plane of polarization, comprising: a dielectric multilayer film having a different incidence angle dependency relative to a first polarized light component and a second polarized light component which have mutually intersecting planes of polarization, wherein the dielectric multilayer film is configured to transmit light of the first polarized light component at a first incidence angle, reflect light of the second polarized light component at the first incidence angle, and transmit light of the second polarized light component at a second incidence angle different from the first incidence angle; a reflecting element configured such that light entering the dielectric multilayer film at said first incidence angle and transmitted through the dielectric multilayer film is reflected from the reflecting element so as to impinge the dielectric multilayer film at an angle equal in magnitude to said second incidence angle; and a quarter-wavelength plate positioned medially to the dielectric multilayer film and the reflecting element, wherein, for incident light impinging on the dielectric multilayer film at the first incidence angle and comprising light having a first polarization direction and light having a second polarization direction: light of the first polarization direction incident on the dielectric multilayer film at the first incidence angle is transmitted through the dielectric multilayer film, light of the second polarization direction incident on the dielectric multilayer film at the first incidence angle is reflected from the dielectric multilayer film, the transmitted light of the first polarization direction is reflected at the reflecting element and is converted to converted light having the second polarization direction by passing through the quarter-wavelength plate twice, and the converted light having the second polarization direction is transmitted through the dielectric multilayer film at the second incidence angle, such that the reflected light of the second polarization direction and the converted light having the second polarization direction emerge from a same side of dielectric multilayer film.