Patent ID: 8358469

Claim:
An immersion microscope objective, comprising, in order from an object side: a first lens group having a positive refractive power, comprising a cemented lens composed of a plano-convex lens whose plane surface faces the object side and a meniscus lens whose concave surface faces the object side, and at least one single lens having a positive refractive power; a second lens group having a positive refractive power, comprising a three-piece cemented lens; and a third lens group having a negative refractive power comprising a Gaussian type lens structure, wherein the immersion microscope objective satisfies the following conditions: 1.7≦ n 1 0.75≦ NAob≦ 1.45 0.4≦ NAob*d 0≦3 0.03≦ NAob/ β≦0.1, where n1 is a refractive index at a d-line of the single lens having a highest refractive index included in the first lens group, NAob is a numerical aperture on the object side of the immersion microscope objective, d0 is a working distance of the immersion microscope objective, and β is a magnification of the immersion microscope objective.