Patent ID: 8237876
Filing Date: 2012-08-07
Classification: G02B,G02F,H04N

Abstract:
1. A liquid crystal display projector comprising: a light source; an optical illumination system for converging light emitted by the light source to an optical path having a principal axis; a liquid crystal display panel, oriented in a panel plane and having a slow-axis and a fast-axis therein, for optically modulating the light converged by the optical illumination system; a projection lens for magnifying and projecting the light modulated by the liquid crystal display panel; a first polarizing means, disposed to accept the light converged by the optical illumination system, for transmitting a first linearly polarized light having a first linear polarization axis onto the liquid crystal display panel with on-axis incidence; a second polarizing means, disposed to accept the light optically modulated by the liquid crystal display panel, for transmitting a second linearly polarized light having a second linear polarization axis to the projection lens; and a retardance compensating plate having a uniaxial C-symmetry, rotated away from the panel plane by an acute tilt angle about an axis of rotation and disposed between the liquid crystal display panel and at least one of the first and second polarizing means, wherein the axis of rotation is parallel to the panel plane; wherein one of a slow and a fast axis of the retardance compensating plate is aligned with the axis of rotation; wherein the axis of rotation is non-parallel to the first and second linear polarization axes, and wherein a retardance profile of the tilted retardance compensating plate having uniaxial C-symmetry substantially matches that of the liquid crystal display panel, and wherein the retardance compensating plate includes a dielectric thin-film form-birefringent coating having a plurality of inorganic transparent layers, the dielectric design tailored such that the retardance compensating plate substantially compensates for residual on- axis and off-axis retardance of the liquid crystal display panel.