Patent ID: 6251068
Filing Date: 2001-06-26
Classification: A61B

Abstract:
An endoscopic observation system, comprising:an optical image pickup system having an objective lens of a variable observation distance to pick up images of a subject through an observation window provided at a distal end of an endoscopic insertion instrument;an illumination system having at least a couple of illumination means located on the opposite sides of and substantially in the same plane as said observation window of said optical image pickup system;said illumination means each having a light guide and an illumination lens for diverging illuminating light from said light guide toward a subject under examination;said illumination means on the opposite sides of said observation window being located in positions spaced from said observation window by such a distance as to hold illuminance in peripheral portions of an imaging area of said subject to a level lower than 200% of an illuminance level in a center portion of said imaging area at the time of observation from a minimal observation distance of said objective lens.