Patent ID: 6992836

Claim:
A lens barrel comprising: a lens-holding cylinder which supports a lens and includes a cam-follower and a rectilinear key; a cam-cylinder having a cam-groove which engages with the cam-follower so as to apply a driving force to the lens-holding cylinder in the optical-axis direction; and a guide cylinder which is enclosed by the cam-cylinder, the guide cylinder having a rectilinear guide opening which engages with the rectilinear key so as to guide the lens-holding cylinder in the optical-axis direction, wherein the cam-cylinder has a first segment and a second segment, the wall thickness of the first segment being greater than that of the second segment such that the first segment has a higher elevation than the second segment in the inner periphery of the cam-cylinder, and wherein the guide cylinder has a first portion and a second portion, the first portion corresponding to the first segment of the cam-cylinder and the second portion corresponding to the second segment of the cam-cylinder, the wall thickness of the second portion being greater than that of the first portion such that the second portion has a higher elevation than the first portion on the outer periphery of the guide cylinder.