| 摘要 |
PURPOSE:To simplify the constitution of a lens driving device and to contrive to reduce its size by rotating a driving lever reciprocally according to a pulse signal, and rotating an operating gear in one direction and moving forth and back a lens barrel. CONSTITUTION:While a circuit is powered-ON prior to range finding operation, a solenoid 22 is driven and the tooth part 24 of the driving lever 20 engages the tooth groove of the operating gear 7. When the range finding operation is finished, solenoids 22 and 23 are driven alternately and a movable part 21 rotates reciprocally around a shaft 27, so the lever 20 is put in reciprocal rota tion in a direction a-b and the operating gear 7 rotates clockwise to extend the lens barrel. Then clock pulses whose number corresponds to a measured range value are supplied to a driving circuit to stop the alternate driving of the solenoids 22 and 23. Consequently, the tooth part 24 or 25 of the lever 7 is held engaged with the tooth groove of the gear and the lens barrel is fixed temporarily at a focusing position. Consequently, feedback constitution, reversible constitution, etc., are not necessary. |
