MEMS Scanning Mirror with Vertical Comb Actuator Based on Latching Technique

Abstract

A MEMS(Micro-Electro-Mechanical Systems) scanning mirror with vertical comb actuator was designed, modeled, fabricated and tested, which can be widely applied in scanning micromirrors, optical switches, and variable capacitors. Purposive latching has been successfully applied to the batch fabrication of vertical comb actuators made of silicon on insulator (SOI). The manufacturing process is introduced, and a novel design of latching structure and mechanical spring is also presented. The latching of microstructures is enabled in a controlled manner and significantly reduces the distance between the combs, reducing the driving voltage. The prototype microactuators operate at the driving voltage of 28 Vdc with 9.6 optical angle. A reliability test on an unpackaged actuator with more than 100 million cycles of operation showed extremely small variation in the scanning angle and the driving voltage, showing no sign of degradation in the induced latching interface or the microstructures.