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. 12, 1988
Filed:
Sep. 26, 1986
Applicant:
Inventor:
Takayuki Itoh, Tokyo, JP;
Assignee:
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350427 ;
Abstract
A high zoom-ratio finite-distance lens with fixed object-to-image distance having arranged from the object side a first lens unit of positive focal length, a second lens unit of negative focal length and third and fourth lens units of positive focal length. The first, third and fourth lens units are moved relative to the second lens units. Conditions are set on the magnifications of the first, second and fourth lens units at the ends of the magnification range, on the relative displacements of the third and fourth lens units and on the location of the entrance pupil.