Investigation of piezoelectric driven MEMS mirrors based on single and double S-shaped PZT actuator for 2-D scanning applications

A silicon micromirror driven by piezoelectric Pb(Zr,Ti)O3 cantilever actuator has been demonstrated for 2-D scanning applications. Two different PZT actuator designs have been fabricated and characterized to investigate the effects of the dimensions and number of S-shaped PZT cantilever actuator folds on the 2-D scanning performances of the micromirror. Three modes of operation have also been investigated for both devices. Device A, which is driven by single S-shaped PZT cantilever actuator, performs better in both dc and ac laser scanning compared to device B, which is driven by double S-shaped PZT actuator. At 10 Vdc, static ODA of 4.6° and 3.3° are obtained for devices A and B respectively. In the ac actuation regime, device A achieved ±9.0° at resonant frequency of 27 Hz, 1 Vpp while device B achieved ±7.2° at 20 Hz, 1 Vpp for bending mode. In torsional mode, dynamic ODA peaks of ±1.8° and ±1.2° are observed at 70 Hz and 156 Hz for devices A and B respectively. Lissajous scan patterns for both devices have been successfully demonstrated by superimposing two ac sinusoidal signals of different frequencies into one signal to be used to actuate the mirror.