Abstract: A piezoelectric electroacoustic transducer includes a substantially rectangular piezoelectric diaphragm having an internal electrode, a plurality of laminated piezoelectric ceramic layers having the internal electrode interposed between two of the piezoelectric ceramic layers, principal-surface electrodes disposed on top and bottom principal surfaces of the piezoelectric diaphragm, the piezoelectric diaphragm generating surface bending-vibrations in response to application of an alternating signal between the principal-surface electrodes and the internal electrode, a resin film that is larger than the piezoelectric diaphragm and having the piezoelectric diaphragm affixed onto substantially a central portion of a front surface thereof, and a housing having a support for supporting the outer periphery of the resin film.

Abstract: A three-terminal filter using the area flexural vibration mode is smaller than filters using the area expansion vibration mode or the length vibration mode, and is easily adjusted to produce a desired frequency by changing the thickness and length of the three-terminal filter. The three-terminal filter includes three electrodes having a substantially square shape, and two piezoelectric layers having a substantially square shape, which are alternately laminated. The piezoelectric layers are polarized in the same thickness direction as the thickness direction, or in opposite thickness directions. The three-terminal filter further includes one surface electrode that functions as an input electrode, another surface electrode that functions as an output electrode, and an internal electrode that functions as a ground electrode.

Abstract: A piezoelectric electroacoustic transducer includes a substantially rectangular piezoelectric diaphragm having an internal electrode, a plurality of laminated piezoelectric ceramic layers having the internal electrode interposed between two of the piezoelectric ceramic layers, principal-surface electrodes disposed on top and bottom principal surfaces of the piezoelectric diaphragm, the piezoelectric diaphragm generating surface bending-vibrations in response to application of an alternating signal between the principal-surface electrodes and the internal electrode, a resin film that is larger than the piezoelectric diaphragm and having the piezoelectric diaphragm affixed onto substantially a central portion of a front surface thereof, and a housing having a support for supporting the outer periphery of the resin film.

Abstract: A piezoelectric electro-acoustic transducer includes a piezoelectric vibration plate having a plurality of piezoelectric ceramic layers laminated to each other with an internal electrode being interposed between the ceramic layers, and main surface electrodes provided on the front and back surfaces thereof, whereby area bending vibration is produced by applying an AC signal between the main surface electrodes and the internal electrode, respectively, a resin film having a size that is greater than the piezoelectric vibration plate and having the piezoelectric vibration plate bonded substantially to the central portion of the surface thereof, and a casing which accommodates the piezoelectric vibration plate and the resin film. The piezoelectric vibration plate has an area of about 40% to about 70% of that of the resin film.

Abstract: A three-terminal filter using the area flexural vibration mode is smaller than filters using the area expansion vibration mode or the length vibration mode, and is easily adjusted to produce a desired frequency by changing the thickness and length of the three-terminal filter. The three-terminal filter includes three electrodes having a substantially square shape, and two piezoelectric layers having a substantially square shape, which are alternately laminated. The piezoelectric layers are polarized in the same thickness direction as the thickness direction, or in opposite thickness directions. The three-terminal filter further includes one surface electrode that functions as an input electrode, another surface electrode that functions as an output electrode, and an internal electrode that functions as a ground electrode.