Electro-mechanical validation of a resonant MEMS mirror with PZT actuation and PZR sensing

MEMS mirrors are used in projection systems based on Laser Beam Scanning LBS and hence they are involved in applications as Augmented Reality Headset and LiDAR. Characterization of the electro-mechanical behavior of MEMS structures plays an important role in the following control strategy definition and system integration. A mono-axial resonant PZT actuated MEMS mirror is addressed and the characteristics of the mechanical structure is investigated by measuring the frequency response of the functional and the main spurious vibrational modes. In addition, a dedicated analysis on the nonlinear behavior is performed Calibration stations with camera sensors are used for optical and electrical analyses while vibrometric and stroboscopic measurement techniques are employed for detecting micrometric movements of the structure. A piezoresistive sensor with Wheatstone bridge configuration is built on board of the MEMS mirror for tracking mirror position during actuation. The combined effects of the functional and spurious modes on the sensor frequency response are evaluated and compared with the MEMS mirror model. In this work, a full characterization on the electro-mechanical parameters of a resonant mono-axial PZT actuated MEMS mirror is presented and a detailed comparison between collected data and model prediction is reported.