Patent Number: 6,251,068

Title: Endoscopic observation system

Abstract: An endoscopic observation means having least a couple of illumination means are provided at a distal end portion of an endoscopic insertion instrument, the illumination means being on the opposite sides of and substantially on the same plane as an optical image pickup means. Each one of the illumination means includes a light guide for transmitting on illumination light from a light source, and an illumination lens for dispersing illumination light over an imaging area of a subject under observation. Further, the endoscopic observation means includes an objective lens system having a variable observation distance. The illumination means on the opposite sides of the observation means are spaced apart from each other by such a distance as to hold illuminance in peripheral portions of an imaging area of the subject to a level not greater than 200%, preferably, in the range of 200% to 120% of an illuminance level in portions of the imaging area.

Inventors: Akiba; Haruo (Omiya, JP), Miyano; Hitoshi (Omiya, JP), Minami; Itsuji (Omiya, JP), Mitsumori; Naotake (Omiya, JP)

Assignee: Fuji Photo Optical Co., Ltd.

International Classification: A61B 1/055 (20060101); A61B 1/07 (20060101); A61B 1/06 (20060101); A61B 001/07 ()

Expiration Date: 06/26/2018