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 mm(2). 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 degrees at 150 V-DC, as well as benefits like great linearity, repeatability and long-term stability. No angle change larger than 0.02 degrees was observed during 100 on-and-off switching circles with 5 s intervals under 100 V-DC. Long-term test over 76 hours under 100 V-DC has shown maximum 0.1 degrees 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.