Design and simulation of a direct and indirect drive electrostatically actuated resonant micro-mirrors for scanner applications

Abstract

Laser scanners have been an integral part of MEMS research for more than three decades. The demand for electrostatically actuated scanning micro-mirrors have been growing in the last decade, mainly for pico-projection and medical applications. These type of actuation wins over others, because it provides long-term stability, size advantages and fabrication schemes which are easier to render CMOS compatibility. The growing field in softwares capable of design and simulate MEMS devices, have been a crucial help for engineers, which are limited to a few of them and still cost huge amount of time. MEMS+® is a software platform that provides simulation results up to 100 times faster than conventional finite element analysis tools and allows to integrate designs in MathWorks®. In this work two types of electrostatically actuated scanning micro-mirrors were designed and simulated using both MEMS+® and MathWorks®, one is a direct drive micro-mirror and the other an indirect drive micro-mirror. In the first the torque is imparted directly from the actuation mechanism to the frame containing the mirror, and in the second the resonance mode amplifies a small motion in a larger mass to a considerably larger motion in the smaller mirror. Regarding the direct-drive micro-mirror, the presented work mainly shows the reliability of MEMS+® compared to other softwares. The indirect drive one, is a state-of-art solution for high frequency electrostatically actuated micro-mirrors, and all the simulations taken on it were aimed to verify it´s behaviour, and then proceed with the microfabrication step. The target microfabrication technology is SOIMUMPs.