Piezoelectric electroacoustic transducer and mfg. method thereof

Abstract

A piezoelectric electroacoustic transducer includes a substantially square piezoelectric diaphragm flexually vibrating in a plate-thickness direction in response to application of an alternating signal between electrodes, a substantially rectangular insulating case having a supporting member disposed inside sidewalls of the case for supporting the diaphragm, terminals having internal connections exposed in a vicinity of the supporting member and external connections exposed outside the case and electrically connecting to the internal connections, a first adhesive applied to a shortest route located between the external periphery of the diaphragm and the internal connections and connecting the diaphragm to the internal connections so as to fix the diaphragm to the case, a conductive adhesive applied to electrodes of the diaphragm and the internal connections via the upper surface of the first adhesive by detouring from the shortest route to connect the diaphragm to the internal connections for electrically connecting the electrodes of the diaphragm to the internal connections of the terminals, and a second adhesive for sealing a clearance between the external periphery of the diaphragm and the internal periphery of the case. The first and second adhesives have a Young's modulus after curing smaller than that of the conductive adhesive.

Description

technical field [0001] The present invention relates to a piezoelectric electroacoustic transducer, such as a piezoelectric buzzer and a piezoelectric receiver, and also relates to a manufacturing method of the transducer. Background technique [0002] So far, piezoelectric electroacoustic transducers have been widely used as piezoelectric buzzers or piezoelectric receivers to obtain alarm sounds or operation sounds in electronic equipment, household appliances, portable phones, and the like. The structure of this piezoelectric electroacoustic transducer is usually: a circular piezoelectric element, which is bonded on one surface of a circular metal plate to form a unimorph diaphragm, and the periphery of the metal plate Supported with silicone rubber in a circular container, the opening of which is closed by a lid. [0003] However, when using a circular diaphragm, there are problems in that production efficiency is low, sound conversion efficiency is low, and miniaturizat...

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Problems solved by technology

[0003] However, when using a circular diaphragm, there are problems in that the production efficiency is low, the sound conversion efficiency is low, and it is difficult to miniaturize

[0007] After the diaphragm sheet is fixed to the container with the elastic supporting material in the above-mentioned manner, even when they are coated with conductive glue, if the diaphragm sheet is opposed to each other on both sides and the supporting member of the container (i.e., for electrical connection with the external electrode The shortest connection path between internal connection parts) is coated with conductive adhesive, and the strain due to the curing and shrinkage of the conductive adhesive is applied to the diaphragm sheet, which may cause a problem of frequency characteristic change

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