Symmetry breaking and mechanical filter make a pseudo-gimbal-less two-dimensional MEMS scanning mirror with multiple scanning modes

Miniaturized two-dimensional scanning mirror based on microelectromechanical systems (MEMS) technology has great potential in automotive industry, consumer electronics, and biomedicine, etc. Due to its high frequency and large angle, resonant scanning is the mainstream in all MEMS actuation mechanisms, such as harmonic resonant electromagnetic scanner and parametric resonant electrostatic scanner. Although electrostatic scanner has the advantages of low power consumption and IC process compatibility, some shortcomings of parametric resonance, including double frequency of driver electronics and additional feedback control or frequency stabilization system, limit its further application. The symmetry of coplanar electrostatic comb actuator is broken in this paper, and harmonic resonant electrostatic scanner with excellent performance is realized. Further, through adopting mechanical filter, two-dimensional scanning can be achieved through one set of actuators, which avoids the problem that two sets (each for one dimension) of electrostatic actuators must be insulated each other through complicated and expensive processes. A two-dimensional MEMS scanner based on symmetry breaking and mechanical filter was proposed and demonstrated. Multiple scanning modes can be achieved through selective control of a set of four identical actuators.