发明名称 Variable focal length lens system
摘要 A variable focal length lens system includes at least three lens groups, in order from an object side, a first lens group G1, a second lens group G2, and a third lens group G3. When the lens group positions are changed from a wide-angle end state to a telephoto end state, each lens group moves from a state focused at infinity to a state focused at near object, in order from a state focused at infinity in the wide-angle end state to a state focused at near object in the telephoto end state. G2 has an aperture diaphragm S, and lens elements are arranged to both object and image side of the aperture diaphragm S. When the lens group positions are changed from the wide-angle end state to the telephoto end state, G1 and G2 moves such that a moving ratio of G2 to G1 is always same, and G3 moves such that a space between G2 and G3 increases when a focusing state in a predetermined focal length changes from infinity to near object, and the space decrease when a focusing state and a focal length state change from near object in the predetermined focal length state to infinity in the next focal length state.
申请公布号 US6333822(B1) 申请公布日期 2001.12.25
申请号 US20000634855 申请日期 2000.08.08
申请人 NIKON CORPORATION 发明人 OHTAKE MOTOYUKI
分类号 G02B15/20;G02B15/167;(IPC1-7):G02B15/14;G02B9/00 主分类号 G02B15/20
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