Angular velocity sensor
First Claim
1. An angular velocity sensor comprising:
- a base;
a vibrator;
a spring device for connecting the vibrator to the base such that a driving vibration can be applied to the vibrator in a first direction and such that the vibrator produces a detecting vibration in a second direction, which is perpendicular to the first direction; and
a detecting electrode opposed to the vibrator, wherein, when an angular velocity is applied to the sensor while the vibrator receives the driving vibration, a change in capacitance between the vibrator and the detecting electrode is produced as a result of the detecting vibration, and the detecting electrode permits the change in capacitance to be detected, wherein a degree of detuning α
is expressed by fd/fs, where fd is a resonance frequency of the driving vibration and fs is a resonance frequency in the detecting vibration, and a term Qs, which is expressed by (m·
k)1/2/c, where m is the mass of the vibrator and k is the spring constant of the spring device, and c is an attenuation coefficient of the vibrator, satisfy a relationship expressed by the following expression;
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Accused Products
Abstract
An improved vibration type angular velocity sensor suppresses temperature variation of the sensitivity in the atmosphere. When the vibrator 31 is subjected to an angular velocity Ω while it is in a driving vibration, it produces a detecting vibration in a direction perpendicular to the direction of the driving vibration. Angular velocity detection is based on a change in capacitance between a comb-like portion 36 of the vibrator 31 and a detecting electrode 50. A relationship between a degree of detuning α=fd/fs, where fd is the resonance frequency in the driving vibration mode and fs is the resonance frequency in the detecting vibration mode, and a value Qs in the detecting vibration mode is given. The term Qs is a function of the mass of the vibrator, a spring constant of springs supporting the vibrator, and an attenuation coefficient.
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Citations
4 Claims
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1. An angular velocity sensor comprising:
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a base;
a vibrator;
a spring device for connecting the vibrator to the base such that a driving vibration can be applied to the vibrator in a first direction and such that the vibrator produces a detecting vibration in a second direction, which is perpendicular to the first direction; and
a detecting electrode opposed to the vibrator, wherein, when an angular velocity is applied to the sensor while the vibrator receives the driving vibration, a change in capacitance between the vibrator and the detecting electrode is produced as a result of the detecting vibration, and the detecting electrode permits the change in capacitance to be detected, wherein a degree of detuning α
is expressed by fd/fs, where fd is a resonance frequency of the driving vibration and fs is a resonance frequency in the detecting vibration, and a term Qs, which is expressed by (m·
k)1/2/c, where m is the mass of the vibrator and k is the spring constant of the spring device, and c is an attenuation coefficient of the vibrator, satisfy a relationship expressed by the following expression;
- View Dependent Claims (2, 3, 4)
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Specification