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. 01, 2014
Filed:
Feb. 24, 2011
Yoshihito Souma, Sakai, JP;
Satoru Shibata, Chiyoda-ku, JP;
Yoshihito Souma, Sakai, JP;
Satoru Shibata, Chiyoda-ku, JP;
Konica Minolta Advanced Layers, Inc., Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
The disclosed internal focusing large-aperture medium telephoto lens has as lens groups a positive first lens group, a positive second lens group, and a third lens group, in that order from the object side. When focusing on nearby objects, the first lens group and the third lens group have a fixed position relative to the image surface, and the second lens group displaces toward the object side. The second lens group has only one negative lens, and, in order from the object side, has at least a positive lens, a negative lens, and a positive lens. The following expression is fulfilled: −0.5<(RR)(RR)<−0.1 (wherein, R: radius of curvature of the object side surface of the negative lens in the second lens group; R: radius of curvature of the image side surface of the negative lens in the second lens group).