Murata Manufacturing Co., Ltd.

Tetsuo Takeshima

Takashi Yamamoto

Toshihiko Unami

Manabu Sumita

Shigemasa Kusabiraki

Jiro Inoue

Takeshi Kishimoto

Toshiyuki Baba

Hirohide Yoshino

Kiyotaka Tajima

Keiichi Kami

Takeshi Yamazaki

Mitsunori Ishimasa

Kazuaki Hamada

Toshio Nishimura

Masakazu Yamauchi

Yuji Kosugi

Yutaka Kawai

Yoshitaka Nakamura

Makoto Irie

Masanaga Nishikawa

Mamoru Ogawa

Muneyuki Daidai

Yuko Yokoi

Akihiro Nomura

Kimitoshi Nakamura

Tadashi Okuzawa

Masayuki Fujino

Tatsunori Kakuda

Yuk Yokoi

Kenichi Takahashi

Yuichi Sakai

A piezoelectric power generating device includes a power generating element and a package member. The power generating element includes a plate-like piezoelectric element and a metal plate. The piezoelectric element has a pair of principal surfaces opposite each other. The metal plate is bonded to one of the principal surfaces of the piezoelectric element. The package member has a supporting part and a restricting part. The supporting part supports an end of the power generating element in a cantilevered manner. The restricting part is disposed opposite the piezoelectric element with the metal plate interposed therebetween. The restricting part restricts displacement of the power generating element toward the outside of the metal plate.

Piezoelectric power generating device

An insert terminal containing case includes a bottom wall, four side walls, and an opening at the upper portion, wherein a terminal made of a metal plate is vertically fixed to at least one of the four side walls by insert molding. A groove is vertically arranged at the outer side surface of the side wall fixing the terminal, the groove extending downward, the outer side surface of the terminal is partially exposed at the groove, and the inner side surface opposite the outer side surface of the terminal exposed at the groove is partially exposed at the inner side surface of the side wall. Therefore, when the terminal is provided in the case by insert molding, molding can be performed only using upper and lower dies. Furthermore, the terminal can be reliably exposed at the inner surface of the side wall. The insert terminal containing case has the minimum difference between the opening dimension of the case and the dimension of a piezoelectric diaphragm and is molded without using a sliding die.

Insert terminal-containing case, piezoelectric electroacoustic transducer using the same, and process for producing insert terminal-containing case

A piezoelectric electroacoustic transducer includes a piezoelectric sounding body in which bending vibration is generated by applying an alternating signal between two electrodes, a case housing the piezoelectric sounding body, and a pair of terminals insert-molded in the case. In the piezoelectric electroacoustic transducer, internal connection portions of the pair of terminals are exposed on the inside surface of the side wall portion of the case so as to extend in a direction that is substantially perpendicular relative to the piezoelectric sounding body, and the internal connection portions of the terminals are electrically connected to the electrodes of the piezoelectric sounding body by using conductive adhesive. The internal connection portions of the terminals do not largely extend inside the case and accordingly, the dimensional difference between the case and the piezoelectric sounding body is minimized.

Piezoelectric electroacoustic transducer

A piezoelectric diaphragm has principal-surface electrodes formed on upper and lower principal surfaces of a multilayer ceramic body. An internal electrode is disposed in an interface between adjacent piezoelectric ceramic layers. The upper and lower principal surfaces of the multilayer ceramic body are substantially entirely covered with a resin layer. A first cutout is formed in a side-edge portion, along the first side surface electrode, of the upper resin layer such that the upper principal-surface electrode is partially exposed in the first cutout. A second cutout is formed in a side-edge portion, along the first side surface electrode, of the lower resin layer such that the lower principal-surface electrode is partially exposed in the second cutout. The locations of the first and second cutouts formed in the upper and lower resin layers, respectively, are selected such that they do not oppose each other.

Piezoelectric diaphragm and piezoelectric electroacoustic transducer using the same

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.

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. The inner peripheral surface of the case is provided with a supporting portion having a frame shape that is larger than that of the piezoelectric vibration plate, and the outer peripheral portion of the resin film having no piezoelectric vibration plate bonded thereto is supported by the supporting portion of the case.

Piezoelectric electro-acoustic transducer

A piezoelectric electro-acoustic transducer includes a substantially rectangular piezoelectric diaphragm, a casing having a support unit for supporting four corners of the piezoelectric diaphragm, terminals fixed to the casing such that an internal connection portion of the terminal is exposed in the vicinity of the support unit, a first elastic adhesive for coating between the external periphery of the piezoelectric diaphragm and the internal connection portion of the terminal therewith, a conductive adhesive for coating between electrodes of the piezoelectric diaphragm and the internal connection portion of the terminal via the upper surface of the first elastic adhesive therewith, and a second elastic adhesive for sealing the external periphery of the piezoelectric diaphragm and the internal periphery of the casing, and a cradle provided in the internal periphery of the casing as well as below the piezoelectric diaphragm in the vicinity that is coated with the first elastic adhesive for forming a gap for stopping flow of the first elastic adhesive at a position lower than the support unit as well as between the upper surface of the cradle and the bottom surface of the piezoelectric diaphragm.

Piezoelectric electro-acoustic transducer and manufacturing method of the same

A piezoelectric electroacoustic transducer is miniaturized and has a reduced frequency, and even when a diaphragm has a warp or winding, the resonance frequency is be stabilized. The piezoelectric electroacoustic transducer includes a substantially rectangular piezoelectric diaphragm flexurally vibrating in a thickness direction in response to the application of an alternating signal between electrodes and a casing for accommodating the piezoelectric diaphragm, wherein the casing is provided with supporting members for supporting four corners of the piezoelectric diaphragm.

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. The resin film has heat resistance at least a reflow-soldering temperature and at least one undulated portion bending in the front and rear directions thereof and formed in the outer periphery thereof, and the perimeter of the resin film including the four corners thereof is fixed to the support of the housing by adhesion.

A piezoelectric type electric acoustic converter achieves large improvement in shatter resistance strength, increased operating efficiency and reduced size, and includes piezoelectric ceramic layers which are laminated to form a laminate. Main surface electrodes are disposed on the front and back main surfaces of the laminate, and an internal electrode is disposed between respective ceramic layers. A side electrode which connects the main surface electrodes, and a side electrode which is conducted to the internal electrode are formed on the side surface of the laminate. All the ceramic layers are polarized in the same direction, and by applying an alternating signal between the main surface electrodes and the internal electrode, bending vibration of the laminate occurs. The front and back surfaces of the laminate is almost entirely covered with resin-layers.

Piezoelectric type electric acoustic converter

A piezoelectric electroacoustic transducer includes a piezoelectric diaphragm having a substantially rectangular shape which vibrates in the thickness direction when an alternating current is applied between electrodes of the piezoelectric diaphragm, a housing which stores the piezoelectric diaphragm, and a pair of terminals formed in the housing by insert molding. One end of each terminal is inserted inside the housing and includes a body portion fixed to the housing and wing portions which extend from both sides of the body portion toward the corners of the housing. The wing portions are not fixed to the housing, and stress-relieving portions are disposed between the body portion and the wing portions so that the wing portions are able to move toward the inside of the housing. Each electrode of the piezoelectric diaphragm is connected to at least one of the wing portions of the terminals by a conductive adhesive.

A piezoelectric electroacoustic transducer includes two electrodes, a substantially square piezoelectric diaphragm producing a bending vibration in the thickness direction thereof in response to application of an alternating voltage between the two electrodes, a housing for housing the piezoelectric diaphragm, an elastic sealant for sealing the gap between the periphery of the diaphragm and the inner side surface of the housing, supports, disposed in the housing, for supporting at least two mutually opposing sides of the piezoelectric diaphragm or the four corners of the piezoelectric diaphragm, grooves which are disposed in the housing so as to face the periphery of the rear surface of the piezoelectric diaphragm and in which the elastic sealant is filled, and walls defining inner portions of the grooves, arranged such that the upper surfaces of the walls are located below those of the supports, for preventing the elastic sealant from flowing out to the bottom of the housing.

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.

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Toyama, Japan

Tetsuo Takeshima