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:
May. 08, 1979
Filed:
Jan. 25, 1978
Applicant:
Inventors:
Akira Tajima, Kawasaki, JP;
Naoto Kawamura, Iragi, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
350184 ; 350176 ; 350189 ; 350207 ;
Abstract
In a zoom lens consisting of a first lens group having a negative refractive power and a second lens group having a positive refractive power with the air separation between the first and second groups being variable for zooming, there are provided two non-spherical surfaces positioned respectively in the first lens group and on the image side of a diaphragm in the second lens group at optional locations to prevent deterioration of aberrations which occurs when the image angle of the zoom lens is increased.