PIEZOELECTRIC STACK

摘要

Provided is a highly reliable piezoelectric stack with a principal surface electrode sometimes subjected to stress, which can prevent the occurrence of a crack when the principal surface electrode is subjected to stress. A piezoelectric stack (10) is provided with a stack element (3) provided with piezoelectric ceramic layers (1) and first and second effective internal electrodes (2a, 2b) facing each other with the piezoelectric ceramic layer therebetween, first and second side surface electrodes (4a, 4b) formed on first and second side surfaces (3a, 3b) of the stack element and connected to the first and second effective internal electrodes, and first and second principal surface electrodes (5a1, 5b1) formed on at least one of an obverse or reverse principal surface of the stack element and electrically connected to the first and second side surface electrodes.  The piezoelectric stack is configured in such a manner that one or more layers of first dummy electrodes (6a) are provided in a region (3Ra) of the stack element corresponding to a region (Ra) subjected to stress of the first principal surface electrode, and one or more layers of second dummy electrodes (6b) are provided in a region (3Rb) thereof corresponding to a region (Rb) subjected to stress of the second principal surface electrode.