PURPOSE: To drive a motor without the generation of vibration or shock by maintaining a driving voltage to be supplied to the motor at a fixed level after being gradually dropped when a mirror is moved from a photographing position to a finder observing position.
CONSTITUTION: When a capacitor 95 starts electrostatic charge, the voltage Va of a line (a) is gradually boosted. A voltage Vb appearing on a line (b) is proportional to a voltage Vb1. Thereby, a voltage corresponding to either lower voltage out of the voltages Va, Vb is outputted to the output terminal of an operational amplifier 104 and a forward driving voltage Vc outputted to a point (c) is gradually increased in proportion to the voltage Va on the line (a) until the time t2 is satisfied with Va<Vb, and then fixed at the constant level proportional to the voltage Vb1 of the line (b). When the motor is forward driven by the forward driving voltage Vc having said waveform, the motor is gradually led at the time of starting and a driving plate also is gradually rotated while increasing the speed. Consequently, almost all electric and mechanical shock can be removed.
FUJI PHOTO FILM CO LTD
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