The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 12, 2025
Filed:
May. 18, 2018
Nikon Corporation, Tokyo, JP;
Tomoyuki Sashima, Tokyo, JP;
Saburo Masugi, Kawasaki, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An optical system comprises a first lens group having positive refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, arranged in order from an object side, wherein, when focusing, the second lens group moves along an optical axis, and the optical system satisfies the conditional expressions 0.100<BFa/f<0.500 and −5.000<(−G1R1)/f<500.000, where BFa is an air equivalent distance on the optical axis between a lens surface on an image side of a lens disposed closest to an image and the image, f is a focal length of the optical system, and G1R1 is a radius of curvature of a lens surface on the object side for a lens component disposed farthest on the object side in the first lens group.