| 摘要 |
PROBLEM TO BE SOLVED: To obtain the microscope objective which can correct a visible area and a far ultraviolet area at the same time, has very good operability, and also has a very long operating distance. SOLUTION: This is a×>=20 high-power microscope objective lens of an infinite-distance correction type of a retrofocus optical system including a 1st lens group which has negative refracting power on the whole and a 2nd lens group which is arranged closer to an object side than the 1st lens group and has positive refracting power on the whole. In this case, the 1st lens group consists of a cemented lens obtained by combining >=1 convex lens and a concave lens and the 2nd lens group includes a cemented lens constituted by combining >=1 single convex lens and >=1 convex lens and a concave lens; and the microscope objective satisfies (1)1f<|F1|<4.5f and (2) 2.5f<D12 <7.5f, where (f) is the focal length of the whole optical system, F1 is the focal length of the 1st lens group, and D12 is the distance from the peak of the object-side surface of the 1st lens group to the peak of the surface of the 2nd lens group which is farther from the object.
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