A large deflection translatory actuator for optical path length modulation

摘要

A novel translational micro mirror with a circular shape of 3 mm diameter and oscillation frequencies of 500 Hz and 1000 Hz is presented including a design study based on analytical and numerical calculations. The study takes mechanical limits like stress and shock resistivity into account as well as fabrication issues resulting in the design points presented. Considerations and results of this study including stress limits for single crystalline silicon and a FE analysis of the main oscillation mode of the resonant structure will be illustrated. Based on an SOI process with 30 μm thick and highly doped single crystalline silicon several devices were fabricated. For the characterization of the devices a Michelson interferometer set-up was used which allows determining the voltage-deflection curves as a function of the air pressure. Deflections of more than ?50 μm for the 500 Hz device and ?85 μm for the 1000 Hz have been achieved at a pressure of 10 Pa. The target is at ?250 μm and ?180 μm amplitude. In the outlook packaging requirements and approaches will be shown.