On the design of a KNN piezoelectric MEMS resonant scanner for wide-angle and high-frequency scanning

This study designs and realizes a piezoelectric MEMS scanning mirror with large scan angle and high frequency for high-resolution laser beam scanning displays. In this design, the micro-mirror consists of mirror plate (1.2 mm in diameter), torsional springs, two pair of wing-shaped actuators, and supporting beams. The wing-shaped actuators acts as the pure torque generator to drive the torsional spring and mirror plate with good linearity (since no axial/transverse loads), also confining the energy at torsional-spring and mirror to achieve large scan angle (at the scanning mode). By varying the width of the supporting beam, mode coupling is suppressed, and the maximum stress on the beam during scanning is also reduced. Measurements demonstrate the scanner has an optical scan angle of 70-degree (mechanical scan angle of ± 17.5-degree) at the resonant frequency of 37.7 kHz with a unipolar driving voltage of 20 V. Moreover, no vacuum environment is required for the presented scanning mirror to achieve the above scan angle. In summary, compared with existing scanners, the performance of the presented one is competitive in FOM (optical scan angle (θ) × mirror size (D)) when driving at resonant frequency, which satisfies the requirement of 1080 P.