| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lens barrel with which the change of a focal distance and focusing operation are performed with a simple structure without necessitating many parts and a complicated technique, which is inexpensive and whose reliability is high. SOLUTION: A pair of cam grooves consisting of a cam groove 15 by which a rear group lens 4 is moved in the optical axis direction and a cam groove 16 by which a front group lens 6 is moved in the optical axis direction is formed on a cam ring 3, and the front group lens 6 is moved stepwise (in a stair-like state) in the optical axis direction at the flat cam parts Cra, Crc and Cre of the cam groove 15 maintaining the focal distances of WIDE, STANDARD AND TELE states so that the focusing operation is performed. COPYRIGHT: (C)2003,JPO
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