Patent ID: 6104542
Filing Date: 2000-08-15
Classification: G02B

Abstract:
A wide-angle microscope eyepiece lens comprising, in order from the object side to the eye side:(a) a first lens group having a positive refractive power;(b) a second lens group comprising a lens having a concave surface facing the object side, and comprising an air-contacting surface at an end of the second lens group closest to the eye side; and(c) a third lens group having a positive refractive power and comprising a surface contacting air, wherein at least one of the air-contacting surface at the end of the second lens group closest to the image side and the air-contacting surface of the third lens group is aspherical, the eyepiece lens satisfying the conditional expressions:1.0<n.multidot.f/.vertline.R2.vertline.<3.5, and 0.5<f1/f<1.5,wherein R2 is the curvature radius of the concave surface of the second lens group, n is the refractive index (relative to d-line light) of the lens in the second lens group having the concave surface, f is the overall focal length of the eyepiece lens, and f1 is the focal length of the first lens group.