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. 03, 1989
Filed:
Sep. 09, 1987
Hisayuki Masumoto, Sakai, JP;
Akira Fukushima, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
The present invention provides a compact zoom lens system comprising; a first lens group having a positive refractive power; a second lens group having a negative refractive power located at the image side of the first lens group with a first variable air space between the first and second lens groups; and a third lens group having a positive refractive power, located at the image side of the second lens group with a second variable air space between the second and third lens groups, including a positive front lens unit and a positive rear lens located at the image side of the front lens unit with a third variable air space between the front and rear lens units, and having at least one aspheric surface; wherein the first lens group and the front and rear lens units of the third lens group are shiftable to the object side in the zooming operation from the shortest focal length to the longest focal length with changing the first, second and third variable air spaces.