NEW OPTICAL CONFIGURATION FOR LARGE-SCREEN HDTV PROJECTOR

First the diffraction efficiencies of various light-valve arrangements are compared. The arrangement based on total internal reflection is one of the best of these. It requires only around one-quarter of the control-layer deformation that would be necessary for the same light output with a single-transmission arrangement. In the total-internal-reflection arrangement, the large angle between the normal to the control layer and the direction of the output light causes unusual problems for the design of the projection optics. The preferred solution relies on reflective optics with strongly eccentric light paths. Examples for the implementation of this concept are given. Finally the possible configuration of an Eidophor colour projector with total internal reflection is discussed.