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:
Oct. 04, 1988
Filed:
Oct. 08, 1985
Applicant:
Inventors:
Keiji Ikemori, Kanagawa, JP;
Takashi Matsushita, Kanagawa, JP;
Assignee:
Canon Kabushiki Kaisha, , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350426 ;
Abstract
A zoom lens whose first lens group, counting from front, has a negative refractive power and moves axially in differential relation to a following lens group to effect zooming, wherein the first lens group is constructed with a lens unit of negative power followed by another lens unit of positive power, whereby for focusing purposes, the negative lens unit is axially moved, while the positive lens unit is held stationary, to improve the stabilization of aberration correction throughout the entire focusing range.