Patent ID: 6375327
Filing Date: 2002-04-23
Classification: G03B

Abstract:
An illuminating system, comprising:an output screen including a liquid crystal display (LCD), means for generating white light; a light source system for illuminating said output screen with polarized light such that a first portion of light of a first polarization state from the means for generating light is output for imaging without change of polarization state and a second portion of light of a second polarization state is converted to polarized light of the first polarization state for display on said screen, said light source system including: (a) a first polarization selective light processing element including a conicoidal light processing element whose vertex contains a small inlet that receives light from the means for generating white light and the small inlet passes a focused high numerical aperture white light of mixed polarization state and the conicoidal light processing element converts the white light incident on a surface of the conicoidal light processing element from a first circular polarization state into reflected light of a second circular polarization state, the second circular polarization state being orthogonal to that of said first circular polarization state; (b) a second polarization selective light processing element including a first element which reflects light of a second linear polarization state and also transmits light of a first linear polarization state and further including a second optical element for converting light of the second linear polarization state into light of second circular polarization state and upon reflecting from said conicoidal light processing element becomes light of said first linear polarization state, thereby enabling output through the first light processing element of light of the first linear polarization state onto the output screen; and said output screen including at least one of a Fresnel lens and a diffuser for converting the light of the first linear polarization state passed through said Fresnel lens into output beams of specific angular extent to the LCD display which receives output light.