PZT actuated micromirror for fine-tracking mechanism of high-density optical data storage

Abstract

A micromirror actuated by piezoelectric cantilevered unimorphs is proposed as a fine-tracking device for high-density optical data storage. Bending motions of the metal/PZT/metal unimorphs translate an integrated micromirror along the out-of-plane vertical direction. The micromirror alters the optical path of the incident laser beam and linearly steers the reflected laser beam by its out-of-plane parallel actuation. Numerical analysis shows that the actuated micromirror can satisfy the tracking speed imposed by the requirement on the access time for the high-density optical data storage up to few tens Gbit/in. 2 owing to the light mass of the micromirror. In this paper, preliminary characteristics of the micromachined PZT actuated micromirror (PAM) are reported. Only a 3600 Å-thick PZT film deposited by sol–gel process shows both good electrical and mechanical characteristics for the fine-tracking actuator. The micromirror can be easily actuated up to several micrometers under low voltage operation condition well below 10 V.