| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a cam ring and also simplify its structure in the cam mechanism of a zoom lens barrel designed such that cam grooves of two or more types are formed on the same circumferential face of the cam ring. SOLUTION: In the cam mechanism of the zoom lens barrel designed such that the internal or external circumferential face of the single cam ring has cam grooves for two optical elements, one behind the other, which are linearly guided, the cam groove for the front optical element is formed at the rear of the cam ring whereas the cam groove for the rear optical element is formed at the front of the cam ring. COPYRIGHT: (C)2006,JPO&NCIPI
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