THREE-COLOR LIQUID CRYSTAL LIGHT VALVE DOUBLE IMAGE PROJECTION SYSTEM WITH COLOR SELECTIVE PREPOLARIZATION

摘要

A first color selective beam splitter is provided for splitting light from a source into first and second beams, the first beam being blue and the second beam having red and green color components. PPA second beam splitter is provided for directing light of the first beam to a blue liquid crystal light valve. The light valve modulates the polarization of the light in the first beam and returns it to the second beam splitter which converts the modulations of polarization to modulations of intensity in the conventional manner and reflects it to a first projection lens.PPA third beam splitter is provided for splitting the second beam into third and fourth beams having first and second polarization states, respectively. The third beam is reflected to a red filter. The fourth beam is transmitted through a green filter. PPThe output of each filter is a substantially monochromatic beam of a single polarization state. The filter outputs are recombined into a single beam which illuminates a fourth beam splitter. The fourth beam splitter is a main polarizing prism. It reflects light of the first polarization state to the green light valve and transmits light of the second polarization state to the red light valve. The light valves modulate the polarization state of incident light in the conventional manner and return it to the main prism. The main prism recombines the light from the first and second light valves into a single beam which is directed to a second projection lens.