Murata Manufacturing Co., Ltd.

Tomio Shibano

Eiichi Takata

Kazufumi Moriya

Tomoyasu Hasegawa

Tetsuo Osawa

Kaneo Yaji

Nobuhiro Ito

Mamoru Ishibe

Shogo Yoshino

The angular velocity detection element includes: a substrate; a pair of spaced support bodies arranged on the substrate and having support-side electrodes that face each other; a movable body, disposed between the support bodies, having a pair of movable-side electrodes facing the support-side electrodes; and a vibration generator for vibrating the movable body in one direction. The support-side electrodes mounted on the support bodies and the movable-side electrodes that are mounted on the movable body are arranged such that the movable-side electrodes face the support-side electrodes. A pair of displacement detectors detect the displacement of the movable body in one direction when the vibration generator imparts a vibration in one direction to the movable body, and a pair of angular velocity detectors detect, as an angular velocity, a displacement perpendicular to the one direction in which the movable body vibrates when the angular velocity acts on the movable body.

Angular velocity detection element and angular velocity measuring device

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.

Angular velocity sensor

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.

A capacitance-type electrostatic servo acceleration sensor capable of detecting applied acceleration with high sensitivity and with low error without needing an accurate oscillator. The sensor makes use of a PAM (pulse amplitude-modulation) circuit for performing pulse amplitude-modulation in proportion to the acceleration. The sensor is equipped with a capacitance-detecting portion having a movable electrode and a pair of fixed electrodes located on opposite sides of the movable electrode. The movable electrode is displaced in response to the acceleration. A comparator is formed by an operational amplifier, and a servomechanism is formed. The electrically obtained open gain of this operational amplifier is set sufficiently greater than the mechanically obtained gain of the capacitance-detecting portion. A measurement mode period and a force-balanced mode period are repeated alternately. During the measurement mode period, the movable electrode is not constrained by the servomechanism, and a voltage corresponding to the acceleration is applied to a sample-and-hold amplifier. During the force-balanced mode period, the movable electrode is constrained by the servomechanism according to the output from the sample-and-hold amplifier which corresponds to the acceleration, and the movable electrode is short-circuited to ground.

Capacitance-type electrostatic servo acceleration sensor

A capacitor type acceleration sensor is disclosed. In this sensor, an acceleration sensing element 1 has two variable capacitors C1 and C2 that are constructed with a couple of fixed electrodes and a movable electrode located between the fixed electrodes. Electrostatic power generation/feedback means 15 applies to the fixed- and movable-electrode pairs such an electrostatic power as to set the movable electrode at a preset reference position in accordance with the output signal of capacitance-difference detector means 10. The electrostatic power is outputted as an output signal of the capacitor type acceleration sensor. In the capacitor type acceleration sensor, another fixed capacitor Cx of which the capacitance value Cx is larger than the maximum capacitance-difference between the variable capacitors C1 and C2 of which the capacitance values vary in accordance with an acceleration, is connected in parallel with the variable capacitor C2. The capacitance (C2+Cx) is larger than the capacitance of the variable capacitor C1, irrespective of the direction of acceleration.

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Yokohama, Japan

Tomio Shibano