Viewing optical system for use with endoscope

Claim 1

An endoscope viewing system consisting of in order, a rigid objective lens unit receiving light from an object to be examined under illumination, a flexible optical-fiber image guide transmitting the image of the object focused by said rigid objective lens unit on a light receiving end surface of said optical-fiber image guide, said optical-fiber image guide consisting of a multiplicity of optical fibers fixed in side-to-side, parallel fashion, and a rigid eyepiece for observing the image emerging from a light emerging surface at the opposite end of said image guide from said light-receiving surface, the improvement wherein; said rigid objective lens unit consists of a first lens imaging a curved image plane conjugate with an object plane; and wherein the light-receiving end surface of the optical-fiber image guide is curved to substantially conform to said curved image plane of said rigid objective lens unit and is positioned at said image plane, such that all parts of said image are in focus at said light-receiving fiber image guide end surface permitting a sharp image of the object to be observed through said rigid eyepiece.