Patent ID: 9110302
Filing Date: 2015-08-18
Classification: A61B,G02B

Abstract:
1. An endoscope optical system consisting of a first lens group having positive refractive power, an aperture diaphragm, a second lens group having negative refractive power, and a third lens group having positive refractive power, in this order from an object side to an image side, the second lens group moving along an optical axis to perform focusing, and the first lens group comprising a first lens having negative refractive power and a second lens having positive refractive power, in this order from the object side and satisfying the following conditional equations: where H(76) is a height at which a principal ray of an incidence angle of view of 76 degrees during normal observation transmits through a surface on the image side of the first lens, nd01 is a refractive index of the first lens with respect to a line d, and r1 and r2 are respectively curvature radii of a surface on the object side and the surface on the image side of the first lens.