Piezoelectric diaphragm and piezoelectric electroacoustic transducer using the same

A piezoelectric diaphragm comprising:

• a multilayer ceramic body including a plurality of piezoelectric ceramic layers, principal-surface electrodes disposed on upper and lower principal surfaces of the multilayer ceramic body, and an internal electrode provided at an interface between adjacent piezoelectric ceramic layers;
• wherein
• flexure vibration occurs in the piezoelectric diaphragm when an AC signal is applied between the internal electrode and the upper and lower principal-surface electrode;
• the upper and lower principal-surface electrodes are electrically connected to each other via a first side surface electrode disposed on one side surface of the multilayer ceramic body;
• the internal electrode is electrically connected to a second side surface electrode disposed on a side surface that is different from the side surface on which the first side-face electrode is provided;
• the second side surface electrode is electrically connected to a lead electrode disposed on at least on the upper principal surface of the multilayer ceramic body;
• the upper and lower principal surfaces of the multilayer ceramic body being substantially entirely covered with a resin layer;
• a first cutout being formed in a side-edge portion, along the first side surface electrode, of the upper resin layer such that the upper principal-surface electrode is partially exposed in the first cutout;
• a second cutout being formed in a side-edge portion, along the first side surface electrode, of the lower resin layer such that the lower principal-surface electrode is partially exposed in the second cutout;
• and
• a third cutout being formed in a side-edge portion, along the second side surface electrode, of the upper resin layer such that the lead electrode is exposed in the third cutout, and
• the first and second cutouts formed in the upper and lower resin layers, respectively, are at locations that do not oppose each other.