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:
Nov. 01, 1983
Filed:
Dec. 09, 1981
Satoru Tachihara, Tokyo, JP;
Sadao Okudaira, Tokyo, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A rear stop diaphragm type zoom lens is disclosed. The zoom lens is composed, in order from the object side, of a first lens group as a whole having a negative refractive power and consisting of two negative lenses and a positive lens and a second lens group as a whole having a positive refractive power and consisting of two or three positive lenses, a negative lens and one or two lenses including at least one positive lens. An aerial space between the lens groups is varied to thereby vary the magnification, and a stop diaphragm is disposed behind the overall lens system with the stop diaphragm being maintained at a constant position with respect to the focusing surface during variation of magnification.