A Parallel-Bimorph-Type Piezoelectric Actuator for High-Resolution Imager

As minute positioning actuators for high-resolution imagers using CCD(charge coupled device)-chip-shift operation, piezoelectric bimorph actuators having low voltage drive and high-speed response are required. In this study, a highly sensitive parallel-bimorph-type piezoelectric actuator using both-ends support with a U-shaped metal plate is proposed and developed. Firstly, the effectiveness of the proposed actuator is confirmed from the frequency and displacement characteristics in relation to the added mass. Secondly, a parallel-bimorph-type piezoelectric actuator where two bimorphs are arranged parallel to each other is fabricated for use in a high-resolution imager that employs CCD-chip-shift operation for practical applications. Through those experiments, the optimal bimorph length and the U-shaped metal plate length are experimentally obtained for stable and high performance of the imager. A box-shaped package of imager, with a 22-pin, dual-in-line format, and dimensions of 30(L)×20(W)×11(H) mm is obtained. A demand displacement of 8.5×10-3 mm is obtained at a driving voltage of 13 Vp-p (30 Hz pulses).