PURPOSE: To prevent the titled device from undergoing harmful sound generated at the inversion of the driving direction of a focus lens or deterioration of a driving system by once reducing a control speed at the time of inversion and then gradually increasing the control speed.
CONSTITUTION: Focus lens driving speed information outputted from a double- wave rectifier 7 is inputted to a speed control means 14 in a microcomputer 15 through an A/D converter 12. The means 14 outputs the controlled contents to a D/A converter 16 in accordance with the output status of an inversion detecting means 13. Namely, when the change of the direction is detected by the means 3, a speed control value is set up to zero corresponding to the minimum speed. After the elapse of time required for soft start, the speed control value is increased. The speed information converted into an analog value by the converter 16 is transmitted to a focus lens driving circuit 11 to drive the focus lens 2 at a proper speed.
SHIMIZU TOMIO
TAKAHASHI HIROAKI
MORISHITA TADAYUKI
| JPS59201007A | 1984-11-14 |