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:
Jan. 30, 1990
Filed:
Feb. 18, 1988
Hiroshi Endo, Kanagawa, JP;
Sadatoshi Takahashi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens is composed of, as counted from the object side of the lens, a first lens unit or group having a positive refractive power, a second lens unit or group having a negative refractive power, a third lens unit or group having a positive refractive power, a fourth lens unit or group having a negative refractive power and a fifth lens unit or group having a positive refractive power. Assuming that, when varying the magnifying power of the lens from a wide angle end to a telephoto end, an air space between an i-th lens unit and an i+l-th lens unit varies to a degree .DELTA.Di, the i-th lens unit has a focal length fi, the focal length of the whole lens system as obtained at the telephoto end is FT, and a space between the first and second lens units varies to a degree .DELTA.E1 between the wide angle end and the telephoto end, the zoom lens is arranged to satisfy the following conditions: