Murata Manufacturing Co., Ltd.

Fumiya Kurokawa

Shinsuke Ikeuchi

Yutaka Kishimoto

Masayuki Suzuki

Seiji Umezawa

Katsumi Fujimoto

Tetsuya Kimura

Nobuyoshi Adachi

Yoichi Mochida

Yasuhiro Aida

Yuzo Kishi

Anssi Blomqvist

Ville-Pekka Rytkönen

Matti Liukku

A piezoelectric element includes a piezoelectric layer, a first electrode layer, a second electrode layer, and a connecting electrode. The piezoelectric layer includes first and second surfaces, and a through-hole. The second electrode layer is adjacent to the second surface of the piezoelectric layer. The second electrode layer faces the through-hole. The second electrode layer includes silicon as a major component. The connecting electrode is on a connecting surface of the second electrode layer, and the connecting surface faces the through-hole. The connecting electrode is made of a metal. A surface roughness of the connecting surface is greater than a surface roughness of a major surface. The major surface is a portion, other than the connecting surface, of a surface of the second electrode layer, and the surface is adjacent to the piezoelectric layer.

Piezoelectric element

A piezoelectric element includes a second electrode layer on a second surface of a single-crystal piezoelectric layer. A hole continuous with a through-hole is provided in the second electrode layer. The second electrode layer is made of Pt, Ti, Al, Cu, Au, Ag, Mg, or an alloy including at least one of the metals as a main ingredient. A third electrode layer is on one side of the second electrode layer opposite to the single-crystal piezoelectric layer. The third electrode layer includes at least a portion outside of an edge of the hole with a distance maintained relative to the edge of the hole when viewed in a direction perpendicular or substantially perpendicular to the second surface. The third electrode layer is made of Ni or an alloy including Ni as a main ingredient.

A piezoelectric device includes a substrate including a first main surface and a second main surface. A piezoelectric element is on the first main surface. A cover on the first main surface. The cover covers the piezoelectric element and is spaced apart from piezoelectric element on the first main surface side. The piezoelectric element includes a base portion and a membrane portion. The base portion is on the first main surface and has an annular external shape when viewed from the first main surface side. The membrane portion is inside the annular base portion when viewed from the first main surface side. The cover includes a first through hole. The substrate includes a second through hole facing the membrane portion and extends between the first main surface and the second main surface.

Piezoelectric device and acoustic transducer

A piezoelectric device includes a beam portion with a fixed end portion and a free end portion opposite to the fixed end portion. The beam portion extends from the fixed end portion towards the free end portion. The beam portion includes a multilayer body including a piezoelectric layer and first and second electrode layers. A base is connected with the fixed end portion of the beam portion. As viewed from a layering direction of the multilayer body, the base surrounds the beam portion at an interval from the beam portion except for the fixed end portion. As viewed from the layering direction, an average of a dimension of a width of the beam portion in an orthogonal or substantially orthogonal direction to an extension direction of the beam portion is greater than a maximal dimension of a length thereof in the extension direction.

Piezoelectric device

A piezoelectric device includes an outer base, a protruding base, and only one cantilevered portion. A protruding base includes a protrusion and a tip portion. The protrusion protrudes from an internal circumferential surface of the outer base toward a center of a ring shape. The tip portion is connected to the protrusion and located at the center. The cantilevered portion is connected to the tip portion, and extends while being spaced apart from the protrusion. The cantilevered portion includes a fixed end portion and a free periphery. The fixed end portion is connected to the tip portion. The free periphery is located along the internal circumferential surface. The protrusion is located between a first end and a second end of the free periphery.

A piezoelectric device includes a substrate, a piezoelectric element, and a lid. The piezoelectric element includes a base portion and a membrane portion. The base portion is on a first main surface and has an annular outer shape when viewed from a normal direction of the first main surface. The membrane portion is at an inner side portion of the base portion when viewed from the normal direction. The lid is on the first main surface, covers the piezoelectric element, and is spaced apart from the piezoelectric element on the first main surface side. In the substrate, a first through hole extending from the first main surface to a second main surface is facing the membrane portion. The membrane portion includes a through slit.

Piezoelectric device and ultrasonic transducer

A piezoelectric device includes a base portion and an upper layer on an upper side of and supported by the base portion. The upper layer includes a membrane portion that does not overlap with the base portion in plan view. The membrane portion includes at least one piezoelectric layer sandwiched by electrode layers from a top and a bottom thereof. An intermediate layer is between a lower electrode and the base portion. The intermediate layer includes one or more individual layers, and an individual layer exposed as a lower surface of the membrane portion among the one or more individual layers includes a bent portion, which extends from the lower surface of the membrane portion to a lateral wall, on a boundary between a portion defining and functioning as the lower surface of the membrane portion and a portion overlapping with the base portion.

A piezoelectric device includes a membrane portion including a single-crystal piezoelectric layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer is on a first surface. The lower electrode layer is on a second surface facing at least a portion of the upper electrode layer sandwiching the single-crystal piezoelectric layer. The single-crystal piezoelectric layer includes piezoelectric body cleavage directions extending along a boundary line between a cleavage plane occurring when the single-crystal piezoelectric layer is cleaved and the first surface. When viewed in a vertical direction, at least a portion of an upper electrode outer edge and at least a portion of a lower electrode outer edge are non-parallel to at least one of the piezoelectric body cleavage directions.

Piezoelectric device including base portion and membrane portion

An ultrasonic transducer includes first and second acoustic transducers and a housing with a bottomed tubular shape. The second acoustic transducer includes an annular section supporting a second membrane section and contacting an entire periphery of the second membrane section, and an acoustic matching plate facing the second membrane section and spaced apart from the second membrane section. The acoustic matching plate is connected to a surrounding wall portion defining a sealed space with the housing. An ultrasonic transmission path sandwiched between the first membrane section and the second membrane section is provided in the sealed space. A maximum inner width of the ultrasonic transmission path is smaller than a maximum inner width of the surrounding wall portion.

Ultrasonic transducer

A piezoelectric device includes a connecting section connecting a pair of beam sections adjacent to each other. The connecting section is connected to one of the pair of beam sections at a first end portion. The connecting section is connected to another of the pair of beam sections at a second end portion. The second end portion faces the first end portion in a direction in which the pair of beam sections are aligned. A second coupling portion is located along a first coupling portion. The connecting section includes only one first end portion. The connecting section includes only one second end portion. Each of the first end portion and the second end portion is closer to a tip end portion than to a fixed end portion of each of the pair of beam sections.

A transducer includes a base, beams, and a coupler. The beams each include a piezoelectric layer, a first electrode layer, and a second electrode layer. The coupler is fitted in slits between adjacent beams to define a connection between the beams. The coupler extends from an upper portion of the base into each of the slits without a break. A Young's modulus of the material of the coupler is lower than a Young's modulus of the material of the piezoelectric layer. A maximum thickness of the coupler in the upper portion of the base in the direction of the central axis of the base is greater than a thickness of each of the beams.

Transducer including coupler fitted in slits between beams

A piezoelectric transducer includes beam portions each with a fixed end portion and extending in a direction away from the fixed end portion. A base portion is connected to the fixed end portion of each of the beam portions. The beam portions extends in a same plane, and respective extending directions of at least two beam portions are different from each other. The beam portions each include a single crystal piezoelectric layer having a polarization axis in a same direction, an upper electrode layer, and a lower electrode layer. A polarization axis has a polarization component in the plane. An axial direction of an orthogonal axis that is orthogonal to the polarization axis and extends in the above-described plane intersects with an extending direction of each of the plurality of beam portions.

Piezoelectric transducer

A MEMS device includes a piezoelectric layer made of a piezoelectric single crystal, a first electrode on a first surface of the piezoelectric layer, and a first layer covering the first surface of the piezoelectric layer. At least a portion of the piezoelectric layer is included in a membrane portion. The first electrode is covered with the first layer and includes a recess. The piezoelectric layer includes a through hole that passes through the piezoelectric layer between a surface of the piezoelectric layer, which is opposite to the first direction, and the recess at a position corresponding to at least a portion of the first electrode.

MEMS device

A piezoelectric device includes a membrane portion and a piezoelectric layer made of single crystal of a piezoelectric body. At least a portion of the piezoelectric layer is included in the membrane portion. An electrode is provided on a surface of the piezoelectric layer in the membrane portion. The piezoelectric layer includes a first polarization region in a first polarization state and a second polarization region in a second polarization state, and the first polarization region and the second polarization region are spaced apart from each other in a thickness direction or an in-plane direction.

A MEMS device includes a membrane portion, a piezoelectric layer made of a piezoelectric single crystal, a first electrode on a first surface of the piezoelectric layer, a second electrode on a second surface of the piezoelectric layer opposite to the first direction, and a first layer covering the first surface of the piezoelectric layer. At least a portion of the piezoelectric layer is included in the membrane portion. Each of the first electrode and the second electrode has a tapered cross-sectional shape with a width which decreases with increasing distance from the piezoelectric layer on a cross section along a plane vertical to the surface in the first direction.

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Nagaokakyo, Japan

Fumiya Kurokawa