| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive unit of an electromagnetic driving type actuator having a function capable of stably detecting an oscillating state of a movable part with high accuracy. SOLUTION: This drive unit has a resonance frequency following/amplitude control circuit 212 and a driver amplifier 214 constituting a driving signal supplying part for supplying a driving signal (waveform A) of an optical scanner 100, and an amplifier 222 for amplification and a signal processing circuit 224 constituting an oscillation detecting part for detecting an oscillating state of the movable part 112 on the basis of voltage (waveform B) of both ends of a driving coil 132. The signal processing circuit 224 has a signal comparison circuit 226 for extracting a part (waveform C) where a potential is lower than 0 V from the voltage of the both sides of the driving coil 132 and a peak detection circuit 228 for acquiring a maximum value (waveform D) of an output waveform of the signal comparison circuit 226 in order to extract amplitude information and phase information of oscillation of the movable part 112.
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