| 摘要 |
PURPOSE:To improve the diaphragm control precision without using a complicated electric circuit by driving a diaphragm driving member with a motor and energizing this member in the stopping-down direction by an elastic member and providing a diaphragm restoring means. CONSTITUTION:An elastic member 11 energizes a diaphragm driving member 10, which is engaged with a diaphragm member 30 in a lens barrel, in the stopping-down direction, and gear trains 9a and 9b connect a motor 1 having an armature core in a rotor and the diaphragm driving member 10. A state detecting means SW1 detects whether the diaphragm driving member 10 is in the diaphragm opening position or not. If the state detecting means SW1 detects that the diaphragm is not in the open position at the time of power-on or release signal input, the motor 1 is driven to restore the diaphragm driving member 10 to the diaphragm opening position. The motor 1 is rotated in the approximately non-loaded state by the aid of the elastic force of a spring at the time of stopping down, and the diaphragm driving member 10 is restored to the opening position if the member 10 is not in this position at the time of power-on or release signal input. Thus, the diaphragm control precision is improved.
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