EXTENSION STRUCTURE OF LENS BARREL

摘要

PROBLEM TO BE SOLVED: To obtain a multistage zoom lens barrel which has enhanced rigidity and secures a sufficient stroke for barrier opening/closing driving. SOLUTION: The zoom lens barrel is equipped with a helicoid extension structure which extends and retracts at least one lens barrel. The helicoid extension structure has a helicoid idle section wherein neither extension nor retraction is allowed even in case of rotation between the storage position and the photographing-enabled extension position of the lens barrel. The helicoid extension structure has a female helicoid provided to one lens barrel and a male helicoid provided to the other lens barrel; and the female and male helicoids have helicoid idle areas wherein movement along the optical axis is restricted and circumference-directional rotation is allowed when the positional relation between one lens barrel and the other lens barrel is in a storage position state. Further, both lens barrels have shake prevention parts which engage with each other in a slidable state without any play in the circumferential direction and optical-axis direction and guide rotation in the helicoid idle sections when the lens barrels are in positional relation where the positions along the optical axis are at least at the storage position and slightly extended from the storage position.