Tdk Corporation

Kazushi Tachimoto

Yoshiki Ohta

Akihiro Takeda

Hideya Sakamoto

Yoshikazu Shimura

Tetsuyuki Taniguchi

Satoshi Sasaki

Kaoru Kijima

Tatsuya Taki

Ryuhei Sasaki

Nobuo Furukawa

Akira Suzuki

Kenji Horino

Hitoshi Oka

Mitsunao Homma

Toshiki Maruyama

Masayoshi Inoue

Kazuo Miyabe

Yoshiaki Ohta

Katsuya Inaba

Tomohiro Takeda

Junpei Kikuchi

Takahiro Kezuka

Rin Sato

Yuzo Komatsu

Nobou Furukawa

Shinya Syoji

Mahoko Takada

A vibration device includes a bimorph type piezoelectric element having a first main surface and a second main surface facing each other and a vibration member bonded to the second main surface of the piezoelectric element. The piezoelectric element has a first active region disposed closer to the first main surface between the first and second main surfaces and a second active region disposed closer to the second main surface than the first active region between the first and second main surfaces. When a force generated in the first active region is F1, a force generated in the second active region is F2, and a force by which the vibration member restrains the second active region is Fr, F2−F1≥Fr is satisfied.

Vibration device and piezoelectric element

A piezoelectric element includes a piezoelectric body, an electrode layer, and a reinforcing layer. The piezoelectric body has a first main surface, a second main surface, and a side surface. The first main surface and the second main surface oppose each other. The side surface extends in an opposing direction in which the first main surface and the second main surface oppose each other in such a way as to connect the first main surface and the second main surface. The electrode layer is provided in the piezoelectric body. The reinforcing layer is provided on the first main surface. The electrode layer is provided opposing the first main surface and apart from the side surface. When viewed from the opposing direction, the electrode layer has a corner. When viewed from the opposing direction, the reinforcing layer overlaps the corner.

Piezoelectric element and vibrating device

A vibration device includes a piezoelectric vibrator having a piezoelectric element and a diaphragm having a pair of main surfaces facing each other, the piezoelectric element being bonded to the main surface, a vibration member where the piezoelectric vibrator is disposed, and an adhesive member disposed between the diaphragm and the vibration member and bonding the diaphragm and the vibration member. Each of the pair of main surfaces of the diaphragm has a rectangular shape when viewed from a facing direction of the pair of main surfaces, and the adhesive member is disposed in a facing manner on at least a pair of sides of the main surfaces.

Vibration device

In a piezoelectric element, shift of a resonance point to a low-pitched sound side is achieved. A resonance point of a piezoelectric element moves to a low-pitched sound side when an active region is configured to be surrounded by an inactive region as in the configuration of the piezoelectric element. According to the piezoelectric element whose resonance point is moved to a low-pitched sound side, the piezoelectric element can realize a sound pressure that is sufficiently high for practical use when it is applied to an acoustic device.

Piezoelectric element

A piezoelectric element includes a piezoelectric element body including a first principal surface and a second principal surface opposing each other, and a plurality of external electrodes disposed on the first principal surface. A vibration member includes a third principal surface opposing the second principal surface. The piezoelectric element is joined to the third principal surface. A wiring member is electrically connected to the piezoelectric element. The wiring member includes a region located on the plurality of external electrodes and joined to the plurality of external electrodes. The region of the wiring member monolithically covers the plurality of external electrodes when viewed from a direction orthogonal to the first principal surface.

A piezoelectric element includes a piezoelectric body layer, a first electrode, a second electrode, a third electrode, and a conductor. The piezoelectric body layer has rectangular first and second principal surfaces opposing each other, and includes a piezoelectric material. The first electrode is provided on the first principal surface. The second electrode is provided on the first principal surface in such a way that the second electrode is separated from the first electrode. The third electrode is provided on the second principal surface in such a way that the third electrode opposes the first electrode. The conductor is connected to the second electrode and the third electrode. The first electrode has a round corner being rounder than a corner part of the piezoelectric body layer when seen in an opposing direction of the first and second principal surfaces.

A multilayer piezoelectric element includes a piezoelectric element body, a first internal electrode and a second internal electrode, a plurality of first connecting conductors, a plurality of second connecting conductors, and an external member. The piezoelectric element body is formed by laminating a plurality of piezoelectric element body layer. The piezoelectric element body includes a first main surface and a second main surface, and a side surface. The plurality of first connecting conductors are connected to the first internal electrode. The plurality of second connecting conductors are connected to the second internal electrode. The external member is conductive and is bonded to the first main surface in such a way as to cover the first end portions of the plurality of first connecting conductors. The external member is electrically connected to the plurality of first connecting conductors.

Multilayer piezoelectric element and vibrating device

Vibration element

A vibrating device includes a piezoelectric element, a wiring board electrically connected with the piezoelectric element, and a diaphragm including a metal. The piezoelectric element and the wiring board are bonded to the diaphragm. The piezoelectric element includes a piezoelectric element body, a plurality of internal electrodes, and a plurality of external electrodes. The piezoelectric element body has a first principal plane and a second principal plane opposed to each other. The plurality of internal electrodes is disposed in the piezoelectric element body. The internal electrodes are opposed to each other in a direction in which the first principal plane and the second principal plane are opposed. The plurality of external electrodes is disposed on the first principal plane, and is electrically connected with corresponding internal electrodes, of the plurality of internal electrodes. The wiring board has a resin film and a plurality of conductors.

Vibrating device

A vibrating device includes a diaphragm, a piezoelectric element, and a wiring board. The piezoelectric element and the wiring board are bonded to a first principal plane of the diaphragm. The wiring board is electrically connected with the piezoelectric element. The piezoelectric element includes a piezoelectric element body, a plurality of internal electrodes, and a plurality of external electrodes. The piezoelectric element body has a second principal plane, a third principal plane, and a side surface. The third principal plane and the side surface are bonded to the first principal plane. The wiring board has a resin film, a plurality of conductors, and a coating film. The coating film is disposed on the plurality of conductors in such a way as to cover the plurality of conductors. One end portions of the plurality of conductors are exposed from the coating film and electrically connected with corresponding external electrodes.

A piezoelectric element includes first and second electrodes, a first piezoelectric body layer, and a plurality of first through-hole conductors. The first and second electrodes oppose each other. The first piezoelectric body layer is disposed between the first electrode and the second electrode. The plurality of first through-hole conductors penetrates the first piezoelectric body layer and is connected to the first electrode and the second electrode. When seen in an opposing direction of the first and second electrodes, the plurality of first through-hole conductors is arrayed in a matrix.

In a piezoelectric element, internal stress generated in an inactive portion at the time of sintering when a piezoelectric element is fabricated or stress applied from the outside to the inactive portion is absorbed by a recess of a lower surface of a first through hole conductor and a recess of an upper surface of a second through hole conductor. Accordingly, for example, deformation, rupture, or the like of the through hole conductor is prevented, and conduction failure or disconnection of an electrode layer or a through hole conductor is prevented. Further, in the inactive portion, since a protrusion of the piezoelectric layer enters the recess of the through hole conductor, a holding force of the piezoelectric layer with respect to the through hole conductor increases, and deformation of the through hole conductor is prevented or obstructed.

A piezoelectric element body has a first principal surface and a second principal surface. A pair of first electrodes is disposed on the first principal surface. The vibrating body includes a metal plate, an insulating layer, and a pair of second electrodes. The metal plate has a third principal surface and a fourth principal surface. The insulating layer is disposed on the third principal surface. The pair of second electrodes is disposed on the insulating layer. The piezoelectric element and the vibrating body are disposed in such a manner that the first principal surface and the third principal surface oppose each other via the insulating layer. The pair of second electrodes physically contacts the respective first electrodes. The second electrodes are exposed from the piezoelectric element and are separated from all of edges of the insulating layer, when viewed from a direction orthogonal to the third principal surface.

A piezoelectric element includes a piezoelectric body layer, a first electrode, a second electrode, a third electrode, and a first through-hole conductor. The piezoelectric body layer has rectangular first and second principal surfaces opposing each other, and includes a piezoelectric material. The first electrode is provided on the first principal surface. The second electrode is provided on the first principal surface in such a way that the second electrode is separated from the first electrode. The third electrode is provided on the second principal surface in such a way that the third electrode opposes the first electrode. The through-hole conductor penetrates the piezoelectric body layer and is connected to the second electrode and the third electrode. The first electrode has a round corner when seen in an opposing direction of the first and second principal surfaces.

An acceleration sensor capable of improving sensitivity is provided. In the acceleration sensor, although a solder fillet is formed in a lower end of a terminal electrode exposed from a covering portion, the covering portion suppresses the rise of the solder fillet. Due to this, the operation of the acceleration sensor is not easily limited by the solder fillet, and the acceleration sensor can generate electric charge which corresponds to a load more accurately. Therefore, the sensitivity of the acceleration sensor can be improved.

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Tokyo, Japan

Kazushi Tachimoto