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:
Sep. 18, 1990
Filed:
Mar. 17, 1989
Applicant:
Inventor:
Haruo Sato, Kawaguchi, JP;
Assignee:
Nikor Corp., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350432 ; 350458 ;
Abstract
A retrofocus type lens system has a first lens group having a negative refracting power and a second lens group having a positive refracting power in the order named from an object side. The second lens group is constituted by a front group having a positive refracting power and a rear group which has a positive refracting power and is movable along an optical axis to have a focusing function. The rear group of the second lens group has an aspherical lens having at least one aspherical surface. The aspherical lens has a shape with which a negative refracting power is gradually increased from its vertex to its periphery.