A Research of Actuators for Micromirror Control

In this paper, a new thermal actuator for micromirror control with very low operating voltage is described. The actuator consists of three straight polysilicon cantilever arms and a polysilicon winding arm that is inherently twisted due to stress-induced bending. Controlling heat generating positions in those arms, the actuator shows both torsional and vertical motions. Mechanical-electro-thermal FEM simulation results show that the actuator has more than a 1.11 degree twisting angle and a 2.31 μm vertical displacement. In order to enhance torsional motion, design optimization is carried out by using a response surface method called the statistical design support system. After optimization, the total twisting angle improves to 2.05 degrees which is enough to actuate micromirrors for optical beam adjusting, switching and attenuating.