IMAGING OPTICAL SYSTEM, IMAGING APPARATUS FOR ENDOSCOPE AND ENDOSCOPIC SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an imaging optical system for a television camera connected to the eyepiece part of an endoscope so as to be used, which is composed of a small number of lenses, whose aberration is excellently corrected, and which is constituted so that various filters can be easily arranged between the imaging optical system and the imaging device of the television camera even when a focal distance is short, and to provide an imaging apparatus for an endoscope and an endoscopic system utilizing the imaging optical system. SOLUTION: The imaging optical system for the television camera connected to the eyepiece part of the endoscope so as to be used is constituted of a diaphragm; a 1st lens group composed of a negative meniscus single lens having a concave surface on an object side; a 2nd lens group having positive power; and a 3rd lens group having positive power in order from the object side, and satisfies following conditional expressions (1) -0.121<-0.02 and (2) -2.51<-1.4 (wherein f is the focal distance of an entire system; f1is the focal distance of the 1st lens group; and R1is the radius of curvature of the concave surface on the object side of the 1st lens group). COPYRIGHT: (C)2005,JPO&NCIPI