Patent ID: 7486445

Claim:
An immersion type microscope objective comprising, in order from an object side to an image side, a positive lens group Ga, a positive lens group Gb, a lens group Gc, a lens group Gd, and a lens group Ge, wherein: the positive lens group Ga includes a cemented lens obtained by cementing a plano-convex lens whose plane surface faces the object side and a meniscus lens whose concave surface faces the object side, and a positive single lens; the positive lens group Gb is formed by a cemented lens; the lens group Gc includes at least one cemented lens; the lens group Gd includes a meniscus lens having a strongly concave surface that faces the image side; the lens group Ge includes a negative lens Len having a strongly concave surface that faces the object side, and a positive lens Lep; wherein the following conditions are satisfied: 0.5 ≦H 2 /H 1≦0.75, 0.5 ≦H 3 /H 1≦0.65, and 7.8 ≦|f ( Gb )/ f|≦ 20, where H 1 indicates a ray height of a marginal ray emergent from the lens group Gb, H 2 indicates a ray height of a marginal ray incident to the lens group Gd, H 3 indicates a ray height of a marginal ray emergent from the lens group Ge, f indicates a focal length of the entire objective, and f(Gb) indicates a focal length of the lens group Gb; and wherein the following condition is satisfied: 45 ≧νd (Len)− νd (Lep)≧30, where νd(Len) is an Abbe number of glass of the negative lens Len, and νd(Lep) is an Abbe number of glass of the positive lens Lep.