Piezoelectric actuator with wrap-around electrode on inactive constraining layer

摘要

A piezoelectric actuator such as for a hard disk drive or other application has a restraining layer on its side that is opposite the side on which the PZT is mounted. The restraining layer is a stiff material. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses the sign of the bending which increases the effective stroke length of the PZT even further. For simplicity of construction and assembly to the suspension, the PZT actuator may be a multi-layer PZT with the top layer being unpoled or otherwise inactive PZT material, and having a wrap-around electrode so that the actuator can be mechanically and electrically bonded to the suspension or other environment using a single adhesive dispense and cure step.

主权项

1. A piezoelectric actuator assembly having a top side, a bottom side, and at least a first end, the assembly comprising:
a first layer comprising a single active piezoelectric layer, the first layer having a bottom face thereof; a first electrode disposed on the first layer; a second electrode having at least a bottom electrode portion disposed on the bottom face of the first layer; and a second layer on the first electrode, the second layer comprising a stiff material, the second layer acting as a constraining layer to constrain expansion or contraction of the first layer when the first layer is activated by application of a voltage across the first and second electrodes; the first electrode having a wrap-around portion that extends onto at least one of the first end of the assembly, the top side of the assembly, and the bottom side of the assembly; wherein the constraining layer comprises unpoled piezoelectric material.