Projection display systems

Abstract

A projection apparatus has a first light beam having a first state of polarization and containing a first set of primary colors, a first light modulator arrangement for spatially modulating the polarization state of the first light beam to encode a first image thereon in the first set of primary colors, a second light beam having a second state of polarization and containing a second set of primary colors, and a second light modulator arrangement for spatially modulating the polarization state of the second light beam to encode a second image thereon. A polarizing beam splitter having first and second input ports to admit the first and second encoded light beams. Light of one polarization state incident on the first port is transmitted to the output port and light of another polarization state incident on the second port is reflected to said output port so that said transmitted and reflected light is combined into a common output beam at said output port. The first and second images having different polarizations contained in the output beam projected onto a display screen can be viewed with the aid of glasses with selective color filters responsive to the first and second sets of primary colors. By using different sets of primary colors considerable efficiencies and economies can be realized relative to a pure polarization-based system.