OBJECTIVE OPTICAL SYSTEM, HARD MIRROR OPTICAL SYSTEM USING SAME, AND HARD MIRROR

摘要

Provided are an objective optical system that is compact and yet has a wide angle of view and high resolution, and has corrected lens distortion and chromatic aberration; a hard mirror optical system using the same; and a hard mirror. The objective optical system comprises, in order starting from nearest the object, a first lens having negative refractive power and a second lens having positive refractive power, and satisfies conditional formulas (1) and (2). (1)–3 (RL1i+RL1o)/(RL1i–RL1o) –1.3 (2)30 νdL1 RL1o is the radius of curvature of the object-side surface of the first lens, RL1i is the radius of curvature of the image-side surface of the first lens, and νdL1 is the Abbe number of the first lens.