PIEZOELECTRIC ACTUATOR

PROBLEM TO BE SOLVED: To provide a piezoelectric actuator suppressed in the formation of oxygen vacancy on side faces of a laminate (piezoelectric layer) and short-circuited thereby. SOLUTION: A laminate type piezoelectric device 1 comprises: a laminate 2 in which a plurality of piezoelectric layers 21 are laminated and first internal electrode layers 221 and second internal electrode layers 222 are alternately formed between layers of the piezoelectric layers 21, the first internal electrode layers 221 are exposed to one of a set of opposing side faces, and the second internal electrode layers 222 are exposed to the other of a set of opposing side faces, and both the internal electrode layers are exposed on the other set of opposing side faces; a first external electrode layer and a second external electrode layer attached on respective side faces of the set of opposing side faces; and films 4 composed of an oxide covering regions where the first internal electrode layers 221 and the second internal electrode layers 222 are exposed on side faces of the other set of opposing side faces. The laminate type piezoelectric device 1 is enclosed in a case 5 so as to be extensible and contractible in the lamination direction of the laminate 2 together with an inert gas 6 so that both end faces in the lamination direction of the laminate 2 contact with inner walls of the case 5. COPYRIGHT: (C)2011,JPO&INPIT