LENS BARREL

PROBLEM TO BE SOLVED: To provide a lens barrel with reduced thickness by operating a moving means using a cam and other moving means cooperate together as means for moving a plurality of imaging lens frames forward or backward in the direction of an optical axis. SOLUTION: Projections 31 are formed on the peripheral part of a third group frame 30. Locking grooves 61 are formed in a linear frame 60 so as to engage with the projections 31 of the third group frame 30 and block rotation of the third group frame 30 around the optical axis O-O' and movement of the third group frame 30 in the direction of the optical axis O-O'. While the third group frame 30 and straight advancement frame 60 are engaged, they are engaged with the inside of a drive frame 50. Then, the projections 31 of the third group frame 30 rotatable integrally with the linear frame 60 are engaged with the lateral groove 55 of the drive frame 50, so that the three components can integrally move forward or backward in the direction of the optical axis O-O', thereby requiring no cam groove for the third group frame formed in the internal circumferential part of the drive frame 50. Accordingly, the flexibility in arranging the cam is increased, and hence the entire length of the drive frame 50 can be shortened. This contributes to reduction in the thickness of the lens barrel. COPYRIGHT: (C)2008,JPO&INPIT