Objective lens for endoscope

Abstract

Abstract PURPOSE:To obtain a wide-angle objective lens for an endoscope which consists of a front and a rear group while reducing distortion by using an aspherical surface in a specific shape for the object-side surface or rear-side surface of a lens in the front group. CONSTITUTION:A concave lens group (front group) I and a convex lens group (rear group) II are arranged successively from the object side, and a stop S is arranged near the front-side focus position of the lens group II. The objectside surface or image-side surface of one lens in the front group I is made aspherical so that the curvature increase gradually according to the distance from the optical axis.

Inventors

• 👤 Kimihiko Nishioka
• 👤 公彦 西岡

Bibliographic Details