A highly linear piezoelectric quasi-static MEMS mirror with mechanical tilt angles of larger than 10°

This paper presents a new type of piezoelectric quasi-static mirror, which utilizes a three-level-construction comprising a mirror plate (diameter = 0.8 mm), a pillar and four actuators hidden beneath the mirror plate, reducing the chip size to 1.3 mm2 . Special folded springs connecting the pillar and actuators are applied to reduce the mechanical non-linearity. Moreover, the newly developed piezoelectric material AlScN delivers large force enabling a mechanical tilting angle of ±12.5° at 150 VDC, as well as benefits like great linearity, repeatability and long-term stability. No angle change larger than 0.02° was observed during 100 on-and-off switching circles with 5 s intervals under 100 VDC. Long-term test over 76 hours under 100 VDC has shown maximum 0.1°shift. More precise measurements are ongoing. Based on the great linearity a simple closed-loop-control has also been developed and more results will be presented in the near future