Murata Manufacturing Co., Ltd.

Kazufumi Moriya

Yoichi Mochida

Tomoyasu Hasegawa

Eiichi Takata

Tomio Shibano

Tetsuo Osawa

Yoshihiro Konaka

Shinji Kobayashi

Katsuhiko Tanaka

Kennichi Atsuchi

Yosuhiro Negoro

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.

Angular velocity sensor

An angular velocity sensor according to an embodiment of the present invention includes: a supporting substrate; a support-fixing portion disposed in the supporting substrate; a first supporting beam connected to the support-fixing portion; a first oscillator supported with the first supporting beam; a second supporting beam connected to the first oscillator; a second oscillator supported with the second supporting beam oscillating in the direction that a Coriolis force is generated; driving electrodes for driving the first oscillator and the second oscillator in a predetermined direction; and detecting electrodes for detecting the displacement of the second oscillator caused by the Coriolis force applied to the second oscillator, wherein the first supporting beam extends at least in the direction orthogonal to the oscillating direction of the first oscillator, both ends of the first supporting beam being connected to the first oscillator, and a longitudinally intermediate portion of the first supporting beam being joined to the support-fixing portion.

An angular velocity sensor including a framelike vibrator supported on a fixed support portion via a pair of beams. The framelike vibrator is placed into an inertial state by being vibrated by a driving means, and a displacement of the framelike vibrator due to Coriolis force is detected. The fixed support portion is formed on a support substrate made of a material having a different coefficient of thermal expansion in the center of the framelike vibrator, and the beams are T-shaped and include a first beam portion for displacing the framelike vibrator by the driving means in the driving direction, and a second beam portion for displacing the framelike vibrator in the direction of generation of the Coriolis force.

An angular velocity sensor includes a board, a first vibrator, a second vibrator, a vibration generator, a displacement detector and a frequency adjuster. The first vibrator is supported on the board through first supporting beams and arranged so as to be vibrated in the direction of a first axis. The second vibrator is supported on the first vibrator through second supporting beams and arranged so as to be vibrated in the direction of the first axis and in the direction of a second axis at a right angle to the direction of the first axis. The vibration generator cause the first vibrator to vibrate in the direction of the first axis. The displacement detector detects a displacement of the second vibrator in the direction to the second axis when an angular velocity has been applied around a third axis at right angles with the first and second axes. The frequency adjuster adjusts a vibrating side resonance frequency at the time when the first vibrator is vibrated in the direction of the first axis and adjusts a detecting side resonance frequency at the time when the second vibrator is vibrated in the direction of the second axis by an angular velocity applied around the third axis.

A downsized angular velocity sensor is disclosed in which the detection sensitivity is improved. An oscillator oscillatably supported by support beams along two horizontal axes is formed of two rod-like members extending along the Y axis and an interconnecting portion. A hollow region is formed between each of the rod-like members and the interconnecting portion. Displacement detecting sections are disposed in the hollow regions. The displacement detecting sections are each constructed of an antenna-like electrode array, so that a greater amount of change in capacitance generated between the antenna-like electrodes can be obtained.

An angular velocity sensor includes a movable bi-directional electrode and a fixed bi-directional electrode wherein L-shaped electrode plates of the movable bi-directional vibration-urging electrode mesh in spaced relationship with L-shaped electrode plates of the fixed bi-directional electrode. In one embodiment in response to a vibration driving signal applied between the electrodes, a vibration plate vibrates with a large amplitude in one direction parallel to the direction in which bent parts of the L-shaped electrode plates extend. If an angular velocity .OMEGA..sub.Z about the Z axis is applied to the vibration plate, the vibration plate is greatly displaced in the Y direction by Coriolis force. This displacement is detected by a displacement detecting part with high accuracy. In another embodiment, the bi-directional electrodes serve as the displacement detecting part.

In an angular velocity sensor for sensing angular velocities about two axes or an X-axis and a Y-axis which are perpendicular to each other, a frame-shaped oscillator 26 is disposed to the respective support portions 24 fixed on a substrate 22 through support beams 25 and a columnar electrode 33 is disposed in the oscillator 26 by being fixed to the substrate 22 . X-axis displacement sensing units 31, 31 are formed on the right and left sides of the oscillator 26 and Y-axis displacement sensing units 32, 32 are formed to the forward and rearward sides thereof. When an oscillation drive signal is imposed between the oscillator 26 and the columnar electrode 33, an electrostatic attracting force is generated therebetween and the oscillator 26 is oscillated in a Z-axis direction. When an angular velocity .OMEGA.Y is imposed about the Y-axis at this time, the oscillator 26 is displaced to the X-axis by a Coriolis force and the displacement can be sensed by the X-axis displacement sensing units 31, whereas when an angular velocity .OMEGA.X is imposed about the X-axis, the oscillator 26 is displaced to the Y-axis by a Coriolis force and the displacement can be sensed by the Y-axis displacement sensing units 32, so that the angular velocities about the two axes or the X-axis and the Y-axis can be sensed, respectively.

The present invention relates to an angular velocity sensor comprising a tuning fork vibrator which exerts a tuning fork vibration by receiving a driving input and which generates a torque around the axis of a tuning fork owing to Coriolis force by undergoing a rotational action around the center of the tuning fork. The sensor has a detection torsional vibrator which exerts torsional vibration owing to the torque generated by the tuning fork vibrator, whereby the angular velocity sensor detects a rotational angular velocity around the axis of the tuning fork based upon the magnitude of the vibration of the detection torsional vibrator. At least one buffer torsional vibrator is positioned around the detection torsional vibrator for moderating external transmission energy loss of the torsional vibration of the detection torsional vibrator.

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Yokohama, Japan

Kazufumi Moriya