Endoscope Objective Optical System

Abstract

Provided is an endoscope objective optical system including, in order from an object side, an aperture stop, a front group having positive refractive power, and a rear group having positive refractive power, in which the rear group is formed by joining a single lens having positive refractive power and a single lens having negative refractive power and is joined to an imaging device; a joining surface between the single lenses has positive refractive power; and the endoscope objective optical system satisfies following Conditional Expression (1): 0.15<fF/fR<0.5,  (1) where fF indicates a focal length of the front group, and fR indicates a focal length of the rear group.

Dependencies are inferred from the claim text.