Patent ID: 6865064
Filing Date: 2005-03-08
Classification: G02B,H02P

Abstract:
1. A drive apparatus for an electromagnetic drive type actuator, which comprises a movable element, a fixed element, a connection element connecting the movable element and the fixed element to allow the movable element to oscillate with respect to the fixed element, a magnetic field generation element provided to one of the fixed element and the movable element, and a drive coil provided to the other one of the fixed element and the movable element, the movable element being caused to oscillate with respect to the fixed element in accordance with a force generated by the interaction between a current flowing through the drive coil and a magnetic field generated by the magnetic field generation element, the drive apparatus comprising: a drive signal supply element, which supplies to the drive coil a current signal with a periodic waveform that has a frequency substantially equal to a resonance frequency of the movable element and whose current value is zero in a fixed period in one cycle; and an oscillation detection element, which detects an oscillation state based on a timing of a zero-cross point of a voltage waveform between both ends of the drive coil in a period corresponding to the period in which the current value is zero.