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. 25, 1994
Filed:
Aug. 21, 1992
Applicant:
Inventor:
Tetsuya Abe, Hokkaido, JP;
Assignee:
Asahi Kogaku Kogyo K.K., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
359688 ; 359684 ;
Abstract
The improved zoom lens system includes, in order from the object side, a first lens group having a positive power, a second and a third lens group each having a negative power and a fourth lens group having an overall positive power, the fourth lens group being composed of a first sub-group 4a and a second sub-group 4b, which zoom lens system performs zooming by moving the second lens group relative to the overall system, the third lens group being moved relative to the overall system in operative association with the zooming so as to correct the shifting of the image plane due to the zooming which zoom lens system satisfies specific conditions.