Displacement analysis of micromirror composed of large deflection spiral beams

Abstract

We present a new two-axis spiral-shaped micromirror manipulator developed for free space optical switching. The actuator is an electrostatic actuator, comprised of two different parts, which are fabricated using conventional surface micromachining processes and then assembled. In spite of the conventional monolithic self-assembling design approaches, these two parts are fabricated on two different chips and assembled using a spatial-mechanical approach from point of view of a simple MEMS-manufacturing process of each part. Making as one MEMS device becomes a lot of number of processes. Because a fixed place of the screw beam from the mirror device is at the position where only the height of a lower micro pyramid is low compared with the height of a central point. The design utilizes the increased flexibility of the spiral shaped electrode and zipping effect technique in order to increase the maximum tilt angle. The footprint of the assembled device is 600µm×600µm and height of the micro pyramid is 200µm.The switch was simulated using an energy concept and electromechanical coupled model. Its performance was measured statically using a reflection measurement approach. A continuous tilt actuation of 17 degree has been achieved with actuation voltage of 235 volts.