Patent ID: 7184115
Filing Date: 2007-02-27
Classification: G02B,G02F,H04N

Abstract:
1. A modulation optical system for providing contrast modulation of an incident light beam comprising: (a) a wire grid prepolarizer for modifying the polarization of said incident beam of light to provide a polarized beam of light; (b) a wire grid polarization beamsplitter for receiving said polarized beam of light, for transmitting said polarized beam of light having a first polarization, and for reflecting said polarized beam of light having a second polarization orthogonal to said first polarization; (c) a reflective spatial light modulator which receives said polarized beam of light, having either a first polarization or a second polarization, and then selectively modulates said polarized beam of light to encode data thereon, providing both modulated light and unmodulated light which differ in polarization; (d) wherein said reflective spatial light modulator reflects back both said modulated light and said unmodulated light to said wire grid polarization beamsplitter; (e) wherein a first polarization compensator, located between said wire grid polarization beamsplitter and said reflective spatial light modulator, conditions the polarization states of oblique and skew light rays relative to said wire grid polarization beamsplitter, or said reflective spatial light modulator, or both; (f) wherein said wire grid polarization beamsplitter separates said modulated light from said unmodulated light; (g) a wire grid polarization analyzer which receives said modulated light, and which further removes any residual unmodulated light from said modulated light; (h) a second polarization compensator, which is provided for conditioning the polarization states of oblique and skew rays relative to said wire grid polarization beamsplitter and to either of said wire grid polarization analyzer or said wire grid prepolarizer; and (g) wherein said first compensator and said second compensator each comprise one or more birefringement layers, wherein said birefringement layers comprise at least one of the following: an A-plate film, a C-plate film, or a biaxial film.