Design of a Piezoelectric Uniaxial MEMS Micromirror with Integrated Angular Feedback

This paper proposes a novel integrated piezoelectric angle sensor for piezoelectrically actuated MEMS micromirrors to achieve high-sensitivity closed-loop control. Traditional open-loop MEMS micromirrors face nonlinear issues like drift, while existing integrated sensing solutions (piezoresistive sensors) complicate manufacturing, and piezoelectric sensing suffers from low sensitivity. To address this, two micromirror designs (conventional F1 and optimized F2) were fabricated: F2 adopts a hollowed-out stress-concentrating structure at the torsion beam-mirror junction and a differential sensing scheme. Simulations confirm enhanced stress in F2, and experiments show that despite a slight reduction in optical scanning angle, F2's angular sensitivity is 178.79% higher than F1. The F2-based closed-loop system also exhibits superior stability, verifying the method's effectiveness for high-performance self-sensing MEMS micromirrors.