Patent ID: 7714945

Claim:
A liquid crystal display based projection system comprising: a light source; a first polarizer for receiving light from the light source and transmitting a first linearly polarized light having a first linear polarization axis; a liquid crystal display panel for optically modulating the first linearly polarized light, the liquid crystal display panel having a slow-axis and a fast-axis; a second polarizer for receiving the optically modulated light and for transmitting a second linearly polarized light having a second linear polarization axis; a projection lens for projecting the second linearly polarized light onto a screen; and a trim retarder disposed between the liquid crystal display panel and at least one of the first and second polarizers, the trim retarder having an in-plane retardance greater than a residual in-plane retardance of the liquid crystal display panel and having a slow axis, an azimuthal angle of the slow axis selected to be in an azimuthal angle range predetermined to provide a system contrast level that is substantially unaffected by at least one of an orientation of the slow axis of the liquid crystal display panel and orientations of the first and second polarizers.