Murata Manufacturing Co., Ltd.

Denso Corporation

Yoichi Mochida

Shinsuke Ikeuchi

Hideya Horiuchi

Takuo Hada

Kansho Yamamoto

Kazufumi Moriya

Tomoya Jomori

Yutaka Kishimoto

Fumiya Kurokawa

Yoshihiro Konaka

Seiji Umezawa

Katsuhiko Tanaka

Tomoyasu Hasegawa

Masaya Tamura

Nobuyoshi Adachi

Kennichi Atsuchi

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 piezoelectric transformer that includes a vibration portion assembly having an output electrode, an output-side intermediate electrode, an input-side intermediate electrode, and an input electrode. The vibration portion assembly includes n vibration portions. The input electrode includes one to n input electrode pieces. The output electrode includes one to n output electrode pieces. Wiring lines are arranged such that voltages of opposite phases can be respectively applied to a first input electrode piece group of the input electrode pieces corresponding to odd-numbered vibration portions, and a second input electrode piece group of the input electrode pieces corresponding to even-numbered vibration portions. The second output electrode piece and the first output-side intermediate electrode piece are superposed with each other in the thickness direction. The first output electrode piece is not superposed with either of the first and second output-side intermediate electrode pieces in the thickness direction.

Piezoelectric transformer

A piezoelectric transformer that includes a base and an upper layer supported by the base. The upper layer includes a first piezoelectric layer that includes the portion of the upper layer that is interposed between an output electrode and an intermediate electrode, and a second piezoelectric layer that is superposed with the first piezoelectric layer and includes the portion of the upper layer interposed between the intermediate electrode and an input electrode in at least n vibration portions. Moreover, the input electrode includes multiple input electrode pieces and the output electrode includes multiple output electrode pieces. In addition, wiring lines are routed such that voltages of opposite phases can be respectively applied to a first input electrode piece group and a second input electrode piece group with the potential of the intermediate electrode serving as a reference.

A piezoelectric device that includes a base member having an opening therein and an upper layer supported by the base member. The upper layer includes a vibration portion at a location corresponding to the opening in the base member. The vibration portion includes a lower electrode, an intermediate electrode and an upper electrode that are spaced apart from one another in a thickness direction of the piezoelectric device. The upper layer includes a first piezoelectric layer disposed so as to be at least partially sandwiched between the lower electrode and the intermediate electrode, and a second piezoelectric layer disposed so as to overlap with the first piezoelectric layer and so as to be at least partially sandwiched between the intermediate electrode and the upper electrode. The first piezoelectric layer and the second piezoelectric layer are different in relative permittivity in the thickness direction of the piezoelectric device.

Piezoelectric device, piezoelectric transformer, and method of manufacturing piezoelectric device

A vibration angular velocity sensor includes a substrate and a vibrator. The vibrator includes support members, linear drive beams, and a plurality of weight portions connected by the drive beams. The vibrator vibrates the plurality of weight portions by bending of the drive beams. The vibrator is fixed to the substrate through the support members at fixed points of the drive beam. A spring property of the support members is smaller than a spring property of the drive beams.

Vibration angular velocity sensor

A physical quantity sensor has a resonance frequency f1 in same-phase mode and a resonance frequency f3 in same-phase absorptive mode greater than the resonance frequency f1. An absolute value &#x394;f3 is a difference between the resonance frequency f3 in the same-phase absorptive mode and a value that is the product of the resonance frequency f1 in the same-phase mode multiplied by n; an avoidance difference D indicates a degree of deviation of the absolute value &#x394;f3 from the resonance frequency f1 in the same-phase mode. A relation (&#x394;f3&#x3e;n&#xb7;f1&#xb7;D) is satisfied, and, simultaneously, the avoidance difference D is provided to be greater than 0%. This can avoid the vibrational excitation by resonance interference from becoming the maximum displacement.

Physical quantity sensor

In an angular velocity sensor, driven mass portions are disposed on a surface of a base plate at point-symmetrical locations with respect to a central point O. The driven mass portions are connected to a coupling beam to be interconnected. The coupling beam is flexibly supported through connecting portions and driven beam. Detecting mass portions are disposed inside the driven mass portions, and the detecting mass portions are supported by detecting beams to be displaceable in the Z-axis direction. Two adjacent ones of the driven mass portions in the circumferential direction are vibrated by vibration generation portions in opposite phases to each other. When angular velocities are exerted in such a state, the detecting mass portions are caused to displace and vibrate in the direction of thickness of the base plate. Displacement detecting portions detect displacements of the detecting mass portions in the direction of the thickness.

Angular velocity sensor

An acceleration sensor includes a base having an XY-substrate surface which is parallel to an XY plane, a beam portion having a frame shape which is arranged in a floating state above the XY-substrate surface of the base, a beam-supporting fixed portion which supports the beam on the base via supporting units like a beam supported by its both ends, weight portionswhich are arranged so as to float above the XY-substrate surface of the base, and connecting portions which support the weight portionsto the beam portion in a cantilever manner. The weight portions are displaceable in the X-axis direction, the Y-axis direction, and the Z-axis direction by the bending deformation of the frame-shaped beam portion. The beam portion is provided with an X-axis direction acceleration detecting portion, a Y-axis direction acceleration detecting portion, and a Z-axis direction acceleration detecting portion.

Acceleration sensor

An acceleration sensor includes a frame-shaped beam portion disposed above an XY substrate surface of a base in a floating state and a beam-portion supporting/fixing unit arranged to attach the beam portion to the base with support portions so as to be supported on two sides. The acceleration sensor also includes weight portions disposed above the XY substrate surface of the base in a floating state and connecting portions for attaching the weight portions to the beam portion in a cantilever state. The weight portions are movable in three axial directions including an X-axis direction, a Y-axis direction, and a Z-axis direction when the beam portion is deflected. The beam portion is provided with an X-axis-direction acceleration detection unit arranged to detect an acceleration in the X-axis direction, a Y-axis-direction acceleration detection unit arranged to detect an acceleration in the Y-axis direction, and a Z-axis-direction acceleration detection unit arranged to detect an acceleration in the Z-axis direction. The Z-axis-direction acceleration detection unit is disposed near proximal ends of Y-axis-direction extending portions of the beam portion, and the Y-axis-direction acceleration detection unit is disposed near distal ends of the Y-axis-direction extending portions.

An Angular-rate detecting apparatus includes four mass portions connected by at least one support beam, and the mass portions have respective individual vibration generators disposed thereon. The individual vibration generators excite the normal vibration mode by vibrating pairs of the mass portions adjacent to each other in opposite phases. Thus, the mass portions are forcibly vibrated in the normal vibration mode. Angular rate detectors detect displacements of inner frames of central mass portions as an angular rate about an axis perpendicular to a detection direction and also to a vibration direction when the inner frames are displaced in the detection direction while vibrating in the vibration direction.

Angular-rate detecting apparatus

An angular velocity sensor includes a substrate; an impact damping mechanism disposed on the substrate for damping an impact applied to the substrate; an oscillator supported to the inside of the impact damping mechanism displaceable in two directions parallel to the substrate and orthogonal to each other by using an oscillator support beam; oscillation-generating means for oscillating the oscillator in an oscillating direction; and angular-velocity detecting means for detecting a displacement of the oscillator as an angular velocity when the oscillator is displaced in a detecting direction orthogonal to the oscillating direction. The impact damping mechanism damps an impact along at least one direction of the oscillating direction and the detecting direction so as to prevent the impact from being transferred to the oscillator from the substrate.

An angular velocity sensor includes four mass members which are connected by retaining beams, and the retaining beams are fixed to a substrate at node portions which correspond to nodes of the retaining beams when the mass members vibrate such that two adjacent mass members are in opposite phases. The mass members vibrate in an X-axis direction while the overall center of gravity is maintained at an approximately constant position. Two mass members disposed at the central region move in a Y-axis direction in accordance with an angular velocity about a Z axis, and the angular velocity is detected on the basis of the displacements thereof. The mass members vibrate in a stable vibrational state and dimensional errors or other problems, are compensated for by their shapes that are symmetric to each other in the Y-axis direction. Accordingly, the detection accuracy and reliability of the sensor are improved.

An angular velocity sensor includes a substrate; a first vibrator supported on the substrate by a first support beam, such as to be vibratable in a direction parallel to the substrate; a second vibrator supported by a second support beam parallel to the first vibrator, such as to be vibratable in a direction orthogonal to the vibrating direction of the first vibrator; a vibration generator for vibrating the first vibrator parallel to the substrate; an angular velocity detector for detecting the amount of displacement of the second vibrator due to an angular velocity; and a vibration-state monitor provided between the substrate and the first vibrator for monitoring the amount of displacement of the first vibrator when it is vibrated by the vibration detector.

A center mass and a pair of outer masses are connected to each other via supporting beams displaceable in the X-axial direction. When an angular velocity sensor is operated, a vibration generator causes masses to vibrate substantially at opposite phases to each other with respect to the X-axial direction. In this state, if an angular velocity on the Y-axis is added, the displacements of the masses, caused when the masses are displaced in the Z-axial direction, are detected as the angular velocity. Moreover, fixing portions, formed on a substrate, support the nodes of the supporting beams corresponding to the nodes to suppress vibration of the masses from being transmitted to the substrate.

External force measuring device

A capacitance-type external-force detecting device includes a substrate, a moveable unit which is supported by the substrate via a supporting beam and which can be displaced in the detecting direction, a comb-shaped fixed electrode provided on the substrate and including a plurality of fixed electrode units spaced in the detecting direction, a comb-shaped moveable electrode provided on the moveable unit and including a plurality of moveable-side electrode units provided between the corresponding fixed electrode units so that the moveable-side electrode units are meshed with the corresponding fixed electrode units, and a capacitance-detecting unit for detecting the displacement amount of the moveable part, at the time when the external force causes the moveable unit to be displaced in the detecting direction, as the variation in the ratio of the overall capacitance between the fixed electrode units and the moveable electrode units and for outputting a voltage signal substantially in proportion thereto.

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Fujisawa, Japan

Yoichi Mochida