Mems-based Light Valves for Ultra-high Resolution Projection Displays

Ultra-high resolution projectors will improve the visual systems of military flight simulators dramatically. There are changes in aspect angle and aspect rate which fixed-wing fighter pilots can discriminate at long standoff distances, but which cannot be displayed with adequate resolution by the visual systems of contemporary flight simulators. At present the limit of display resolution is fixed by the capacity of the display’s projector. This issue is being addressed by INO and its partners working toward the development of a new light-modulating micromirror MEMS. This unique device incorporates 25 μm x 25 μm microbridges acting as flexible micromirrors. Each micromirror corresponds to one pixel of an image and is capable of modulating light intensity in analog fashion, with switching speeds in the range of 5 μs. A linear array of micromirrors is combined with a scanning system, a microlaser light source and a Schlieren-type optical system to produce a 256 grey-level image. The result is a MOEMS-based system that can write thousands of image lines at a frame rate of 60 Hz. Finite-element analyses have been performed to describe mechanical properties of the micromirrors. Several examples will be given from both static and dynamic electromechanical simulation. The micromirror fabrication process will be summarized. The physical characteristics of the micromirrors will be reported, including their response time and damage threshold. Finally, future plans including the development of 2000 x 1 linear pixel arrays with the associated control electronics, will be described.