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:
Nov. 28, 2000
Filed:
Dec. 04, 1998
Applicant:
Inventors:
Masayuki Murata, Saitama-ken, JP;
Takayuki Ito, Saitama-ken, JP;
Assignee:
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
359693 ; 359740 ;
Abstract
A macro lens system includes a positive first lens group, an aperture and a negative second lens group arranged in the order from an object side. The driving mechanism drives the lens groups and the aperture to move independently along an optical axis for focusing. When the lens groups are moved toward the object side, the aperture is also moved to the object side. The moving amount of the aperture is determined to control increasing of an effective F-number. The moving amount of the aperture is smaller than that of the first lens group and is larger than that of the second lens group.