| 摘要 |
PROBLEM TO BE SOLVED: To provide a microscope zoom objective lens having improved optical performance, and comprising a compact optical system with a zoom ratio of at least 3. SOLUTION: The microscope zoom objective lens comprises a first lens group G1 having positive power, a second lens group G2 having negative power and a third lens group G3 having positive power. For zooming from a low to a high magnification side, the second and the third lens groups G2 and G3 move along an optical axis while the separation between the first lens group G1 and the second lens group G2 becomes wide and the separation between the second lens group G2 and the third lens group G3 becomes narrow. The second lens group G2 has at least two lens groups, which are constituted so that their concave surfaces face each other. When the focal distance of the first lens group G1 is defined as F1, and while the focal distance of the second lens group G2 is defined as F2 and the focal distance of the third lens group G3 is defined as F3, the microscope zoom objective lens satisfies conditions (6) and (7). COPYRIGHT: (C)2007,JPO&INPIT
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