Patent ID: 6796180
Filing Date: 2004-09-28
Classification: G01C

Abstract:
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 &agr; 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 (mÂ·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: Î±&GreaterEqual;5.720Ã—10-9&CenterDot;Q&it;â€ƒ&it;s6-1.012Ã—10-6&CenterDot;Q&it;â€ƒ&it;s5+7.102Ã—10-5&CenterDot;Q&it;â€ƒ&it;s4-2.517Ã—10-3&CenterDot;Q&it;â€ƒ&it;s3+4.736Ã—10-2&CenterDot;Q&it;â€ƒ&it;s2-4.549Ã—10-1&CenterDot;Q&it;â€ƒ&it;s+2.923