Synchronized Oscillation of 2-by-2 Electrostatic Torsional Micromirror Array

We demonstrated synchronized oscillation of 2-by-2 electrostatic micromirror array by tuning electrostatic coupling force, which will be used for high-performance spatial light modulators. The SOI-MEMS device structures were fabricated, and the torsion beams are patterned using two step Bosch process. The unit torsional resonant mirrors were coupled by vertical comb electrodes and driven by a common ac oscillation voltage and dc bias voltage. The coupling stiffness was tuned by the bias voltage, while the same ac actuation signal is applied to all mirrors. The phase variation between mirrors is smaller than ±0.2 °.