Performance modeling of liquid crystal phase diffraction gratings suitable for HDTV projection systems

Because of the inherent inefficiency associated with polarization-rotation liquid crystal light valves in an high intensity environment, this paper discusses the applicability and performance of these valves operated as phase diffraction gratings in HDTV projection systems. A numerical method for evaluating performance and optimizing design parameters is presented. The resulting model is used to consider design improvement to increase the modulation efficiency and to adapt the projector to use unpolarized light as well as linearly polarized light. The modeling results are used to determine and optimize the parameters of the liquid crystal panel, such as, the refractive index of the liquid crystal, the thickness of liquid crystal cells, and the width of panel pixels.