| 摘要 |
Detection electrodes 82 D and 82 E are formed at positions that include an antinode of a flexural oscillation mode. The strain of flexural oscillation reaches a maximum and the effects on the phase difference in the longitudinal oscillation mode can be cancelled out. The detection electrodes 82 D and 82 E are formed at the positions of drive electrodes 82 B and 82 C used to excite the flexural oscillation mode. A phase difference in the flexural oscillation mode opposite in sign relative to the longitudinal oscillation mode is created making it is easy to classify based on the phase difference between a frequency at which the longitudinal oscillation mode is dominant and a frequency at which the flexural oscillation mode is dominant. Thus, reliable control can be achieved based on the oscillation behaviors at each frequency ensuring a satisfactory drive force based on oscillation in the longitudinal oscillation mode.
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