For some types of digital projectors, the illumination path, projection path, and off-sate light path have an angular separation. For example in DLP™ (digital light processing) digital projectors, an illumination path is off-axis and a projection path is on-axis. This creates a geometrical challenge when combining different-colored light from each of three modulated light pixel arrays (or modulators) and maintaining separation between the illumination path, the projection path, and a beam dump path of the projector.
USPTO Backgrounds
USPTO Backgrounds