Patent ID: 8597457

Claim:
A method of bonding a flat end surface of a pillar-shaped laminated piezoelectric element in an expansion direction to a bonded surface of a bonded object using an adhesive agent in a state in which said laminated piezoelectric element is not displaced in the expansion direction, wherein said laminated piezoelectric element comprises a plurality of internal electrodes which are laminated in the expansion direction, wherein said laminated piezoelectric element has an effective area of the internal electrodes in which the internal electrodes are opposed to one another and has a dead area at outer regions thereof outside of the effective area of the internal electrodes, wherein the effective area of said internal electrodes is smaller than an outside shape of said laminated piezoelectric element, and wherein the flat end surface includes the effective area and the dead area, said method comprising: applying said adhesive agent to the flat end surface of said laminated piezoelectric element at the effective area of the internal electrodes alone so as to avoid the dead area of said laminated piezoelectric element; and bonding the flat end surface of said laminated piezoelectric element to the bonded surface of said bonded object, wherein said applying comprises: forming, in the bonded surface of said bonded object, a cavity having a size in a direction perpendicular to the expansion direction which is equivalent to that of the effective area of said internal electrodes of said laminated piezoelectric element; and accumulating said adhesive agent in said cavity.