Patent Number: 6,252,723

Title: Objective optical system

Abstract: An objective optical system comprising, in order from the object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power and a third lens unit having a positive refractive power, wherein the second lens unit is moved along an optical axis for changing a magnification. This objective optical system is configured to be compact and have favorable optical performance by adequately selecting an airspace between the first lens unit and the second lens unit as well as a power for the first lens unit.

Inventors: Nagaoka; Toshiyuki (Hachioji, JP)

Assignee: Olympus Optical Co., Ltd.

International Classification: G02B 15/163 (20060101); G02B 23/24 (20060101); G02B 15/173 (20060101); G02B 015/14 (); G02B 003/00 (); G02B 009/00 (); G02B 027/02 (); A61B 001/06 ()

Expiration Date: 06/26/2018