Murata Manufacturing Co., Ltd.

Mikio Nakashima

Kiyoshi Iyama

Sachihito Nakafuku

A piezoelectric electroacoustic transducer, including a plurality of piezoelectric layers deposited to define a deposited product, flexurally vibrates the deposited product by polarizing the entire piezoelectric ceramic layers in the same thickness direction and also by applying an alternating signal between external electrodes disposed on the front/rear major surfaces of the deposited product and an internal electrode disposed between the ceramic layers. A dummy electrode is provided between the ceramic layers outside the internal electrode via a gap, and a portion of the internal electrode is exposed at at least one side surface of the piezoelectric ceramic layers, while the dummy electrode is exposed at the other side surface of the piezoelectric ceramic layers. The external electrodes extend to the side surfaces other than the side surface at which the internal electrode is exposed.

Piezoelectric electroacoustic transducer and manufacturing method of the same

A plurality of polarization electrodes are provided oppositely on front and back surfaces of a piezoelectric ceramic substrate, while the polarization electrodes on the front surface and the polarization electrodes on the back surface are connected respectively by connecting electrodes which are formed on positions not opposed to each other. A dc voltage is applied across the polarization electrodes on the front and back surfaces for polarizing the substrate to form a plurality of polarized portions in the substrate. Thus, it is possible to reduce stress concentration in polarizing process, thereby inhibiting the substrate from cracking.

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Toyama-ken, Japan

Mikio Nakashima