LED projector with two liquid crystal on silicon light valves and a fly’s eye integrator

We present a projection system with two liquid crystal on silicon light valves that are illuminated by light-emitting diode light sources (LEDs). The LED illumination system is designed with a fly’s eye integrator. Using this integrator we combine for each primary color two LEDs into one bright source to illuminate the light valve. In the color management system a wire-grid polarizer is used to combine two beams with opposite state of polarization. The contrast behavior of our two LCOS approach is investigated with a basic model and ray tracing. The consequences of using this polarizer are discussed. We present contrast, uniformity and light output measurements of a concept demonstration set-up.