Patent ID: 7869132

Claim:
An immersion microscope objective having an object side and an image side and comprising, in order from the object side: a first lens group having positive refractive power; a second lens group having positive refractive power; a third lens group; a fourth lens group having negative refractive power with its surface nearest the image side being concave; and a fifth lens group having positive refractive power with its surface nearest the object side being concave; wherein said first lens group includes a cemented lens component formed of, in order from the object side, a lens element of positive refractive power and a meniscus lens element having its concave surface on the object side; and the following conditions are satisfied: 0.75 <h 1 /h 0<1 0.4 <h 2 /h 1<0.6 0.8 <h 3 /h 1<1.3 where h0 is the largest ray height on any lens surface in the immersion microscope objective, h1 is the marginal ray height on the surface of the fourth lens group nearest the object side, h2 is the marginal ray height on the surface of the fourth lens group nearest the image side, and h3 is the marginal ray height on the surface of the fifth lens group nearest the image side.