| 摘要 |
A microscope objective lens of medium or high magnification having a great working distance and yet having an excellent imaging performance comprises, in succession from the object side, a first lens group of positive refractive power for converting a light flux from an object into a convergent light flux, the first lens group having a positive meniscus lens component having its concave surface facing the object side and a cemented lens component, a second lens group having a cemented lens component of small refractive power disposed in the convergent light flux, and a third lens group having a meniscus lens component having its convex surface facing the object side and a succeeding negative lens component. The objective lens satisfies the following conditions: ¦r1¦>¦r2¦>f 3f>1/2¦r1¦>d1 dF+dA>dR where r1 and r2 are the radii of curvature of the object side and image side lens surfaces, respectively, of the positive meniscus lens component in the first lens group which is most adjacent to the object side, d1 is the center thickness of the positive meniscus lens component, f is the focal length of the entire system, dF is the center thickness of the meniscus lens component in the third lens group which has its convex surface facing the object side, dR is the center thickness of the negative lens component, and dA is the air space between the meniscus lens component and the negative lens component.
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