Patent ID: 9097850
Filing Date: 2015-08-04
Classification: A61B,G02B

Abstract:
1. An endoscope objective lens comprising, in order from an object side, a positive first lens group, a negative second lens group, and a positive third lens group, wherein the first lens group has only one meniscus lens; and a normal observation state (wide angle end) and a magnifying observation state (telephoto end) can be switched between by moving the second lens group on an optical axis, and the following conditions are satisfied;  where f wherein the second lens group consists of a joined lens that is formed of a concave lens having a first refractive index and a convex lens having a second refractive index lower than the first refractive index; and a lens surface of the second lens group that is located closest to an object and a lens surface thereof that is located closest to an image each have a planar shape.