A Novel High Performance Piezoelectrically Driven Microlens Actuator for Micro-Optics Applications

This paper presents a novel high performance piezoelectrically driven microlens actuator for micro-optics applications. The actuator exhibits large out-of-plane displacement of 228 μm at 22 V with a device footprint area of less than 36mm
²
and power consumption of 3.5 mW. The resonant frequencies of the actuator with and without a microlens load are 0.89 kHz and 2.1 kHz, respectively. Such actuation performances are achieved by using UHV E-beam evaporated polysilicon as the device platform where the residual stress can be controlled to alter the initial static deflection of the actuator. We report two cases of initial downward deflections (47 μm and 98 μm) obtained by targeting the residual stress of the polysilicon and SiO
₂
layers through judicious choice of deposition and processing parameters. Comparing both devices, the later resulted in a stroke range and actuation sensitivity enhancement of 47.6% and 64.7%, respectively.