Three color channel, two-elevation optics for a single lens video projector

摘要

A high-efficiency optical system for use in a liquid-crystal light-valve video projector. High intensity, unpolarized white light is separated into primary color components by color-selective filters transmitting light containing both first and second polarization states. Light of each primary color is characterized by a wavelength passband whereby the endpoints of the passband are defined by first and second wavelengths. The second passband endpoint of the first polarization state of the first primary color overlaps the first passband endpoint of the second polarization state of the second primary color, and the second passband endpoint of the second polarization state of the second primary color overlaps the first passband endpoint of the first polarization state of the third primary color. In addition, the video projector design utilizes low f/# optics in conjunction with absorptive polarizers to remove residual light of an unwanted polarization state allowed into the system by the low f/# optics. This allows high brightness with high efficiency and without sacrificing contrast.