Evaluation of electromechanical properties and field concentrations near electrodes in piezoelectric thick films for MEMS mirrors by simulations and tests

We examine the nonlinear electromechanical response of piezoelectric mirrors driven by PZT thick films in a combined numerical and experimental investigation. First, some electromechanical tests were performed to measure the response (displacement versus load, displacement versus electric field) of the PZT thick films on elastic layers. A finite element analysis was then employed to determine the material properties in the PZT thick films using measured data. Next, the mirror tilt angle and electromechanical field concentrations due to electrodes in piezoelectric mirrors under electric fields were analyzed by introducing a model for polarization switching in local areas, and a nonlinear behavior was discussed in detail. The mirrors consisted of four fully or partially poled PZT unimorphs. Test results on the mirror tilt angle versus electric field, which verify the model, were also presented.