Dynamics Of Thin-Film Piezoelectric Vertical-Rotational Scanning Actuator

Certain advanced optical endomicroscopy techniques, including dual axes confocal and multi-photon microscopy, require the ability to perform a combination of large displacement axial and fast lateral scanning in a small form factor, to generate real-time vertical cross sectional images in vivo. Vertical translational microactuators with 200 gm or more of axial scanning range have been coupled with passive internal scanning mirrors achieving up to 6 mechanical scanning angle, suitable for imaging applications. This paper examines the influence of nonlinearities associated with large axial stroke on actuator dynamics. Coupling of internal mirror platform resonance with lateral compliance of the axial scanning stage is found to produce dramatic variation in resonant frequency of the mirror at varying stage heights. Smaller non-idealities are identified in asymmetrical stage rotation and piezoelectric forcing.