Patent ID: 7764449

Claim:
A piezoelectric actuator comprising: a piezoelectric body having a first piezoelectric body and a second piezoelectric body, the first piezoelectric body comprising a multi-layer stack of a plurality of first ceramic sheets and a second ceramic sheet having a pattern-printed ground electrode interposed therebetween, the plurality of first ceramic sheets having first and second internal electrodes pattern-printed to be spaced apart from each other at a predetermined distance each arranged such that the first internal electrode is superimposed on a first vibration part and the second internal electrode is superimposed on a second vibration part; a second piezoelectric body comprising a multi-layer stack of the plurality of first ceramic sheets and the second ceramic sheet interposed therebetween, the plurality of first ceramic sheets each arranged such that the first internal electrode is superimposed on a second vibration part and the second internal electrode is superimposed on a first vibration part; and an electrode part comprising a first external electrode, a second external electrode and a ground external electrode, the first external electrode formed on an outer surface of the piezoelectric body to connect to a terminal of the first internal electrode, the second external electrode formed on the outer surface of the piezoelectric body to connect to a terminal of the second internal electrode, and the ground external electrode formed on the outer surface of the piezoelectric body to connect to a terminal of the ground electrode; and a friction member disposed on the outer surface of the piezoelectric body to transfer vibration generated from the piezoelectric body to the outside.