Actuator using piezoelectric element and head-positioning mechanism using the actuator

Abstract

An actuator having a simple configuration requiring no high dimensional accuracy, high in positioning accuracy and low in cost, and a head-positioning mechanism using the actuator are disclosed. An actuator according to a first application comprises a shear-type piezoelectric element of predetermined thickness and an opposed electrode formed on two electrodes in spaced relationship on a base member. The opposed electrode is displaced in accordance with the direction of polarization of the shear-type piezoelectric element upon applying a voltage between the two electrodes. The opposed electrode thus constitutes an operating section of the actuator. An actuator according to a second application comprises a movable member arranged on a drive member including a shear-type piezoelectric element on a base member. The drive member includes a plurality of layers of piezoelectric elements polarized in alternately opposite directions perpendicular to the thickness of the devices. A plurality of conductive layers are formed adjacently to the respective layers of the devices to permit voltage application thereto. The movable member can be driven in parallel to the base member upon application of a voltage between the conductive layers. Any one of these actuators can be incorporated as a part of the head actuator to constitute a head-positioning mechanism capable of displacing the head by a minuscule distance independently of the operation of the head actuator.