Large-stroke convex micromirror actuated by electromagnetic force for optical power control

This paper contributes a novel design and the corresponding fabrication process to research on the unique topic of micro-electromechanical systems (MEMS) deformable convex micromirror used for focusing-power control. In this design, the shape of a thin planar metalcoated polymer-membrane mirror is controlled electromagnetically by using the repulsive force between two magnets, a permanent magnet and a coil solenoid, installed in an actuator system. The 5 mm effective aperture of a large-stroke micromirror showed a maximum center displacement of 30.08 μm, which enabled control of optical power across a wide range that could extend up to around 20 diopters. Specifically, utilizing the maximum optical power of 20 diopter by applying a maximum controlling current of 0.8 A yielded consumption of at most 2 W of electrical power. It was also demonstrated that this micromirror could easily be integrated in miniature tunable optical imaging systems.