Reflective liquid crystal spatial light modulator and projection apparatus comprising same

摘要

Reflective spatial light modulators (RSLMs) and projection apparatus employing such RSLMs are disclosed. The RSLM comprises a reflective surface and a superposed light-modulation layer. The reflective surface is configured to have a reflective diffraction optical element or a microfaceted reflective array. Incident light impinging on the RSLM can pass through the light-modulation layer, reflect from the reflective surface, and return through the light-modulation layer to become modulated signal light capable of forming a viewable image if projected onto a screen or other surface. The reflective diffraction optical element or microfaceted reflective array on the reflective surface is operable to cause the signal light to propagate from the RSLM in a different direction than any ghost light reflected from the RSLM. Projection apparatus employing such an RSLM comprise an illumination optical system, a projection optical system that may or may not be coaxial with the illumination optical system, and a stop operable to pass signal light but not ghost light to a screen for viewing. The viewed image has enhanced contrast over the prior art.