Color separation-synthesizing optical system for LC projector, has dichroic mirror whose wavelength cut-off characteristics depends on projection angle of light, so that mean wavelength of light is equal

摘要

Optical system has dichroic mirrors (30,31A) which split R, G, B light and irradiate on liquid crystal light valves (34R,34G). Dichroic prisms synthesize R, G, B color light. The wavelength cut off characteristics of the mirror (31A) depends on the projection angle ( tau 1, tau 2) of light projected from lens (23), so that the mean wavelength of the light irradiated on the LC light valve is equal. Independent claims are also included for the following: (a) Optical integrator; (b) Lighting system; (c) Liquid crystal projector