American Institute of Aeronautics and Astronautics 1 A High Speed Electrostatically Actuated Al-MEMS Micromirror Array Adam D. Mathias, 1 Jon R. Fox, 2 and Stephen B. Horowitz 3 Miltec Corporation, Emerging Technologies Group, Huntsville, AL, 35806 and Mark G. Temmen 4 AMRDEC, Redstone Arsenal, AL 35898 The design of an electrostatically-actuated, aluminum, torsional micromirror, on the order of 20x20 microns, is presented. The design is repeated in 25x25 arrays for high-speed deflection of incident light as an optical shutter. Future designs would include individually addressable micromirror elements. Parameterization of geometries is described and the resulting optimized micromirror design is detailed. The COMSOL Multiphysics finite element analysis environment is utilized to study the optimized design. Within the finite element analysis software, a 132 V electric potential is applied to an underlying electrode in order to produce a minimum of 5° tilt which yields a downward mirror-edge displacement of 1.39 μm into a 4 μm gap between the electrode and the bottom of the micromirror. When the electric potential is removed, it is shown that the micro-mirror has a settle time ~10 μs. The prototypical micromirror arrays are fabricated using an Al-MEMS fabrication process. The developed fabrication process uses a 4 micron sacrificial photo-definable polymer and a sub- micron thick aluminum layer suspended over patterned gold electrodes. The sacrificial polymer was plasma-ashed to release the deformable aluminum structures. Nomenclature E = Young's modulus of micromirror material, GPa G = shear modulus of micromirror material, GPa ν = Poisson's ratio of micromirror material L = length of torsional beams, μm W = mirror width, μm t = mirror thickness, μm L T = length of torsional beam, μm l b = length of side section of the torsional beam, μm l bc = length of center section of the torsional beam, μm w b = width of side section of the torsional beam, μm w bc = width of center section of the torsional beam, μm t b = thickness of the torsional beam, μm T = twisting moment of the torsional beam l e = length of driving electrode, μm w e = width of driving electrode, μm t e = thickness of driving electrode, μm h = gap height, μm 1 Aerospace Engineer, 689 Discovery Drive, Huntsville, AL 35806 2 MEMS Engineer, 689 Discovery Drive, Huntsville, AL 35806 3 Director of Emerging Technologies Group, 689 Discovery Drive, Huntsville, AL 35806 4 Research Engineer, Weapons Sciences Directorate Infotech@Aerospace 2011 29 - 31 March 2011, St. Louis, Missouri AIAA 2011-1578 Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Go