US 2012/0057730 A1 · PIEZOELECTRIC ACOUSTIC TRANSDUCER

Abstract

A piezoelectric acoustic transducer (1) of the present invention includes a lower frame (78), a lower speaker circuit (20), an upper frame (77), an upper speaker circuit (10), and a surround (76). The upper speaker circuit (10) has a piezoelectric diaphragm (14) in which piezoelectric elements (16, 17), each having a structure that flat plate electrodes are disposed on top and bottom of a piezoelectric member, are mounted on top and bottom surfaces of a board (15). The lower speaker circuit (20) has a piezoelectric diaphragm (24) in which piezoelectric elements (26, 27), each having the same structure, are mounted on a top surface and a bottom surface of a board (25). The piezoelectric diaphragms (14, 24) are coupled to each other via coupling members (74, 75). At an application of a voltage, the piezoelectric diaphragms (14, 24) are caused to curve in directions opposite to each other. Having this structure, the piezoelectric acoustic transducer (1) has an increased displacement in a thickness direction thereof, and thereby achieving high quality sound with space-saving.

Claims9

Dependent claims

A piezoelectric acoustic transducer that vibrates in accordance with a voltage applied thereto, the piezoelectric acoustic transducer comprising:

a plurality of piezoelectric diaphragms each having a piezoelectric element mounted on at least one main surface of a board;
and
a plurality of coupling members for aligning a vibration axis of the piezoelectric element of each of the plurality of piezoelectric diaphragms with each other, and for coupling adjacent piezoelectric diaphragms of the plurality of piezoelectric diaphragms to each other, wherein
the polarity of the piezoelectric element of each of the adjacent piezoelectric diaphragms is set so that the adjacent piezoelectric diaphragms are displaced in directions opposite to each other, in accordance with a voltage applied thereto, and
one of the plurality of piezoelectric diaphragms that is disposed on one side is coupled, in a center of the board, to a non-vibrating fixed frame of the piezoelectric acoustic transducer, and is coupled, in end portions, of the board, perpendicular to directions in which the piezoelectric element expands or contracts, to the adjacent piezoelectric diaphragm via the plurality of coupling members.

2 more elements

Dependencies are inferred from the claim text.

Piezoelectric acoustic transducer

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Piezoelectric acoustic transducer

Life of this patent

Abstract

Claims9