Experiments of a grating light modulator for projection display applications

A micromechanical optical modulator called a grating light modulator (GLM) with electrostatic actuation, fabricated by the conventional process, is described. The GLM is operated by the interaction of a stationary reflector and a movable sliding grating. The GLM is a micromechanical phase grating. The phase difference is determined by the slide of the movable part (upper grating), allowing different diffraction patterns of reflected light. In addition, 100% modulation in the first/zero order can act as an optical switch and produce bright or dark pixels in a projection display system. Built using microelectromechanical system technology, and designed to be manufactured using mainstream integrated circuit fabrication technology, a 256-pixel GLM array is fabricated. We also describe projection display applications of a GLM as a high efficiency spatial light modulator. The optimized display system with a GLM is theoretically discussed in detail. The single-color and three-color experimental results indicate that the GLM technology has characteristics that make it suitable for projection display applications. (C) 2009 Optical Society of America