Gyro sensor and composite sensor comprising gyro sensor
First Claim
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1. A gyro sensor comprising:
- a substrate including a fixed portion;
a movable portion connected to the fixed portion via a support beam and including a drive weight having a mass portion, wherein a plane being parallel with a planar surface of the substrate and including an x-axis and a y-axis orthogonal to the x-axis is referred to as an xy plane, a direction along the x-axis is referred to as an x-axis direction, and a direction along the y-axis is referred to as a y-axis direction, and wherein, when an angular velocity is detected, the mass portion is reciprocally rotationally vibrated in the xy plane or reciprocally vibrated in the y-axis direction on the basis of a displacement of the support beam;
two detection weights connected to the drive weight via detection beams and arranged in the x-axis direction;
a coupling spring coupling the two detection weights to each other; and
detection electrodes placed to be spaced apart at predetermined distances from the two detection weights in a z-axis direction as a direction along a z-axis perpendicular to the xy plane,wherein it is configured that, as a result of an application of the angular velocity, the two detection weights are vibrated oppositely in the z-axis direction to cause changes in the respective distances between the two detection weights and the detection electrodes and cause anti-phase changes in capacitance values of two capacitors formed between the two detection weights and the detection electrodes and, on the basis of the anti-phase changes in the capacitance values, the angular velocity is detected using a differential output of signals showing the changes in the two capacitance values, andwherein the coupling spring includes torsion springs connected respectively to the two detection weights, and a middle rigid body coupling the torsion spring connected to one of the detection weights to the torsion spring connected to the other detection weight.
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Abstract
In a gyro sensor, two detection weights are placed in an outer drive weight to be arranged in an x-axis direction and coupled to each other via a coupling spring. By thus coupling the two detection weights via the coupling spring, it is possible to separate an in-phase-mode resonant frequency fin and an anti-phase-mode resonant frequency fanti from each other. As a result, it is possible to provide the gyro sensor which can suppress an output error on receiving an impact and perform more precise angular velocity detection.
10 Citations
14 Claims
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1. A gyro sensor comprising:
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a substrate including a fixed portion; a movable portion connected to the fixed portion via a support beam and including a drive weight having a mass portion, wherein a plane being parallel with a planar surface of the substrate and including an x-axis and a y-axis orthogonal to the x-axis is referred to as an xy plane, a direction along the x-axis is referred to as an x-axis direction, and a direction along the y-axis is referred to as a y-axis direction, and wherein, when an angular velocity is detected, the mass portion is reciprocally rotationally vibrated in the xy plane or reciprocally vibrated in the y-axis direction on the basis of a displacement of the support beam; two detection weights connected to the drive weight via detection beams and arranged in the x-axis direction; a coupling spring coupling the two detection weights to each other; and detection electrodes placed to be spaced apart at predetermined distances from the two detection weights in a z-axis direction as a direction along a z-axis perpendicular to the xy plane, wherein it is configured that, as a result of an application of the angular velocity, the two detection weights are vibrated oppositely in the z-axis direction to cause changes in the respective distances between the two detection weights and the detection electrodes and cause anti-phase changes in capacitance values of two capacitors formed between the two detection weights and the detection electrodes and, on the basis of the anti-phase changes in the capacitance values, the angular velocity is detected using a differential output of signals showing the changes in the two capacitance values, and wherein the coupling spring includes torsion springs connected respectively to the two detection weights, and a middle rigid body coupling the torsion spring connected to one of the detection weights to the torsion spring connected to the other detection weight. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A gyro sensor comprising:
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a substrate including a fixed portion; a movable portion connected to the fixed portion via detection beams and including two detection weights each having a mass portion, wherein a plane being parallel with a planar surface of the substrate and including an x-axis and a y-axis orthogonal to the x-axis is referred to as an xy plane, a direction along the x-axis is referred to as an x-axis direction, and a direction along the y-axis is referred to as a y-axis direction, and wherein, when an angular velocity is detected, the mass portion is reciprocally rotationally rotated in the xy plane or reciprocally vibrated in the y-axis direction on the basis of a displacement of each of the detection beams; two drive weights formed integrally with the two detection weights and arranged in the x-axis direction; a coupling spring coupling the two detection weights to each other; and detection electrodes placed to be spaced apart at predetermined distances from the two detection weights in a z-axis direction as a direction along a z-axis perpendicular to the xy plane, wherein it is configured that, as a result of an application of the angular velocity, the two detection weights are vibrated oppositely in the z-axis direction to cause changes in the respective distances between the two detection weights and the detection electrodes and cause anti-phase changes in capacitance values of two capacitors formed between the two detection weights and the detection electrodes and, on the basis of the anti-phase changes in the capacitance values, the angular velocity is detected using a differential output of signals showing the changes in the two capacitance values, and wherein the coupling spring includes torsion springs connected respectively to the two detection weights, and a middle rigid body coupling the torsion spring connected to one of the detection weights to the torsion spring connected to the other detection weight. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification