Murata Manufacturing Co., Ltd.

Takeshi Kishimoto

Tetsuo Takeshima

Takashi Yamamoto

Kazuaki Hamada

Muneyuki Daidai

Akihiro Nomura

Masayuki Fujino

A piezoelectric electroacoustic transducer eliminates the need for the interconnection between main surface electrodes and internal electrodes, and is capable of constructing a bimorph diaphragm using a simple connection structure. The piezoelectric electroacoustic transducer includes a laminated body formed by laminating two or three piezoelectric ceramic layers, main surface electrodes each provided on the top and bottom main surfaces, and an internal electrode provided between any adjacent two piezoelectric ceramic layers. In the piezoelectric electroacoustic transducer, all ceramic layers are polarized in the same direction with respect to the thickness direction, and by applying an alternating voltage across the main surface electrodes and the internal electrode, the laminated body generates a bending vibration in its entirety.

Piezoelectric electroacoustic transducer

A piezoelectric acoustic component having excellent efficiencies of productivity and of acoustic conversion, a greatly miniaturized size, and excellent impact resistance properties, includes a unimorph type diaphragm. The unimorph type diaphragm is defined by adhering a substantially square piezoelectric element onto a substantially square metal plate, the shorter sides of the diaphragm are supported on the supporting portion provided within the two opposing side wall portions of the case, the clearance between the remaining two sides of the diaphragm, and the case is sealed with a resilient sealing agent. The case is adhered on the substrate having external electrodes, the metal plate is connected to the external electrode with a resilient conductive paste, and the surface electrode of the piezoelectric element is connected to the external electrode with a resilient conductive paste. In this arrangement, the reliability of connection between the diaphragm and the external terminals on the substrate against the impact is greatly improved.

Piezoelectric acoustic components

A piezoelectric electro-acoustic transducer is constructed such that adherence of a piezoelectric diaphragm to a casing is easily performed, a sufficient supporting strength is achieved, and the piezoelectric diaphragm is supported while hindrance of vibration thereof is minimized. This piezoelectric electro-acoustic transducer includes a piezoelectric diaphragm constructed by adhering a piezoelectric ceramic plate having front and back surfaces including electrodes, onto a metallic plate, and a case in which the piezoelectric diaphragm is accommodated by fixing the peripheral portion thereof with an elastic adhesive. Support portions for supporting the peripheral portion of the piezoelectric diaphragm are provided in the case, and a supporting surface having an arcuate cross-section is provided on the supporting portions so that a center of curvature of the supporting surface is positioned near a lower surface of the peripheral portion of the piezoelectric diaphragm.

Piezoelectric electro-acoustic transducer

A piezoelectric acoustic component includes a diaphragm having a substantially rectangular piezoelectric plate including front and back surfaces, an electrode disposed on the front surface, a substantially rectangular metal plate bonded to the back surface of the substantially rectangular piezoelectric plate directly or via an electrode disposed on the back surface of the substantially rectangular piezoelectric plate, an insulating cap having an upper wall, four side walls extending from the upper, a pair of support members arranged to support the diaphragm at the inside of the two of four sides walls opposed to each other, and a plate shaped substrate having a first electrode section and a second electrode section. The diaphragm is disposed the insulating cap. Two of four side edges of the diaphragm are opposed to each other and fixed to the pair of support members. A gap is formed between the other two of four side edges of the diaphragm and the cap and is sealed by elastic sealing material. An acoustic space is provided between the diaphragm and the upper wall of the insulating cap. An opening edge of the four side walls of the insulating cap is bonded to the substrate. The metal plate is electrically connected to the first electrode section. The electrode disposed on the front surface of the substantially rectangular piezoelectric plate is electrically connected to the second electrode section.

Piezoelectric acoustic component

An electroacoustic transducer includes a diaphragm including a substantially rectangular metal plate and a substantially rectangular piezoelectric plate having electrodes on an upper surface and a lower surface thereof, with one of the electrodes being connected to the metal plate. A support medium including retaining parts for retaining two shorter sides of the diaphragm is provided. The shorter sides of the diaphragm are fixed to the retaining parts by an adhesive having a Young's Modulus after curing that is between about 4.0&times;10 N/m and about 5.0&times;10 N/m . Gaps between the two longer sides of the diaphragm and the support member are sealed by an elastic sealant. The diaphragm is arranged to undergo bending vibration in a longitudinal bending mode by applying a predetermined electrical signal between the metal plate and the opposing electrode provided on the piezoelectric plate.

Electroacoustic transducer

A piezoelectric acoustic component includes a unimorph-type vibration body, a mounting substrate, and a cover. The vibration body includes a substantially rectangular piezoelectric plate and a substantially rectangular metallic plate bonded to the back side of the piezoelectric plate. Longitudinal opposite end portions of the vibration body are fixed onto the mounting substrate via respective support members. The metallic plate of the vibration body is fixedly connected to a first electrode located on the mounting substrate via one of the support members, whereas the electrode located on the front side of the piezoelectric plate is connected to a second electrode located on the mounting substrate via a conductive wire. A gap between the mounting substrate and each of lateral opposite end portions of the vibration body is charged with silicone rubber, thereby defining an acoustic space between the vibration body and the mounting substrate. A cover having a sound release hole formed therein is bonded onto the mounting substrate so as to cover the vibration body without contacting the same.

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Toyama-ken, Japan

Takeshi Kishimoto