FILM-TYPE PIEZOELECTRIC/ELECTROSTRICTIVE ELEMENT

摘要

A film-type piezoelectric/electrostrictive element which is a fired object includes a body part, a pair of side-surface electrodes and an electrode exposed surface. The body part has n+1 layered piezoelectric/electrostrictive films and n layered internal electrode layer(s). The piezoelectric/electrostrictive films are composed of ceramic. The piezoelectric/electrostrictive films and the internal electrode layer(s) are stacked in an alternating manner. The n is an integer equal to 1 or more. The pair of side-surface electrodes is positioned on two opposing side surfaces. The two opposing side surfaces extend in a stacking direction of the body part. The internal electrode layer(s) is/are exposed on an electrode exposed surface of a side surface of the element. The electrode exposed surface extends in the stacking direction of the piezoelectric/electrostrictive films and the internal electrode layer(s). A surface coverage ratio of the internal electrode layer(s) on the electrode exposed surface as defined by Formula (1) being more than 0% and less than or equal to 10%. The surface coverage ratio % = A �¢ 1 / L �¢ 1 × L �¢ 2 × 100 ) A1 denotes an exposed area of the internal electrode layer(s) exposed on an active portion of the electrode exposed surface. L1 denotes an average thickness of the internal electrode layer(s). L2 denotes a sum length of each of the internal electrode layer(s) in a lengthwise direction on the active portion of the electrode exposed surface.