Infocus Systems, Inc.

Gary B Kingsley

Arlie R Conner

Jonathan R Biles

Terry J Scheffer

An optical notch filter component in a color LCD display comprises an electronically controllable variable retarder interposed between circularly polarizing elements. Entering light in a particular spectral region is circularly polarized by a first of the circularly polarizing elements, and selectively retarded by zero or a half wavelength by the retarder so as to controllably yield right or left handed circular polarization. The second circular polarizer transmits only one of the circular polarizations of the light. By controlling the circular polarization of the light with the retarder, the light is either transmitted or attenuated. More uniform stopband attenuation is provided when the optical notch filter component comprises oppositely handed circular polarizing elements and a variable retarder which applies zero retardation in one of its states. A direct view display system substantially without parallax effects is formed from a stacked assembly of the notch filter components with thin substrate construction. Higher contrast is provided by doubly analyzing each color band.

Notch filters with cholesteric polarizers with birefringent film and

A projector (100) including an liquid crystal display image source (120), a field lens (126), and a projection lens (128) projects a full-color image by projecting and converging images of multiple liquid crystal displays ('LCDs'). The image is properly positioned without keystoning by tilting the field lens and offsetting the center of the LCD image source from the optical axis (142) of the projection lens. Trapezoidal error is eliminated by maintaining the optical center (156) of the field lens on the optical axis of the projection lens. During focusing, a mounting apparatus (164) adjusts the offset (154) between the center of the LCD and the optical axis of the projection lens for proper convergence of the images and maintains the optical center of the field lens on the optical axis of the projection lens.

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Tualatin, OR, United States of America

Gary B Kingsley