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:
Jul. 09, 2013
Filed:
Jun. 16, 2011
Masahiro Mizuta, Yokohama, JP;
Fumio Suzuki, Yokohama, JP;
Masahiro Mizuta, Yokohama, JP;
Fumio Suzuki, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An optical system including, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having negative refractive power. The second lens group has, in order from the object, a front group having negative refractive power and a rear group. In various embodiments, the following conditional expressions are satisfied, 0.4<f2F/f2<1.6 and −3.0<q2<−0.3 where f2 denotes a focal length of the second lens group, f2F denotes a focal length of the front group, and q2 denotes a form factor of a negative lens disposed closest to the object of the front group.