Patent ID: 8331006

Claim:
An apparatus comprising: a light source configured to emit light; an illuminating unit configured to provide illuminating light by distributing light emitted from said light source; a reflective light modulator array comprising a plurality of pixels configured to modulate said illuminating light; and imaging optics configured to focus or collimate light reflected from said pixels, wherein said illuminating unit comprises a substrate having two surfaces separated by a substantially constant distance, said substrate further comprising: an in-coupling portion configured to couple light of said light source into said substrate to form a waveguided beam which is confined to said substrate by total internal reflections on said surfaces; an integrating portion configured to reduce spatial variations in the intensity of said waveguided beam, the ratio of the length of said integrating portion to the thickness of said integrating portion being greater than or equal to 10; and an out-coupling portion configured to provide said illuminating light by coupling light of said waveguided beam out of said substrate.