公开(公告)号：US20180364466A1

公开(公告)日：2018-12-20

申请号：US16006543

申请日：2018-06-12

Applicant: OLYMPUS CORPORATION

Inventor： Kenichiro ABE ,  Masaru KOBAYASHI ,  Kazuhiko YAMANOUCHI ,  Toru KANEDA ,  Masaki AKAHANE

IPC: G02B21/02 ,  G02B9/64

Abstract: An objective includes a first lens group that has a positive refractive power and a second lens group that has a negative refractive power. The objective satisfies conditional expressions below. 0.2≤NAob≤1  (1) 2.9 mm≤D0×NAob≤30 mm  (2) 30 mm≤L≤70 mm  (3) 0.0001≤RMSh/λh≤0.035  (4) NAob is a numerical aperture on an object side of the objective. D0 is a distance on an optical axis between an object plane and a lens surface of the objective that is situated closest to the object side. L is a distance on the optical axis between the object plane and a lens surface of the objective that is situated closest to the image side. RMSh is an axial RMS wave aberration with respect to the h line. λh is a wavelength of the h line.