| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly-accurate variable-capacity type acceleration sensor utilizing a tuning-fork type piezoelectric vibrator. SOLUTION: An acceleration sensor element 1 has a pair of vibration arms 3, 4 extending in parallel from a base part 2, three detection arms 5-7 elongating in parallel along both sides of the vibration arms and the interval therebetween from a weight part 10 positioned ahead, and connection parts 8, 9 having a narrow width for bonding detection arms on both sides to the base part. Capacitors C1-C4 formed respectively of the second excitation electrode on the vibration arm side face and a detection electrode on the adjacent detection arm side face form a bridge circuit. When the connection parts are bent by an acceleration, and the weight part and the detection arm are displaced integrally, by application of an AC current and by excitation of the vibration arms, gaps between each capacitor are fluctuated and each capacitance is changed, and thereby the magnitude and the direction of an acceleration are detected by detecting synchronously an output from the bridge circuit. COPYRIGHT: (C)2009,JPO&INPIT
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