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, 2001
Filed:
May. 02, 2000
Shuji Yoneyama, Saitama, JP;
Nobutaka Minefuji, Saitama, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A photographic lens comprising: a front lens group and a rear lens group that are arranged in order from the object side; wherein the front lens group comprises, in order from the object side, a first lens element which is a positive meniscus lens having a convex surface facing the object side, a second lens element which is a positive meniscus lens having a convex surface facing the object side, and a third lens element that is cemented to the second lens element, the third lens element being a negative meniscus lens having a convex surface facing the object side; wherein said rear lens group comprises, in order from the object side, a fourth lens element which is a positive meniscus lens having a convex surface facing the image side; a fifth lens element which is a negative meniscus lens having a concave surface facing the object side; a sixth lens element that is cemented to the fifth lens element, the sixth lens element being a positive meniscus lens having a convex surface facing the image side; and wherein the front lens group and the rear lens group are moved toward the object side so that the distance between the front and rear lens groups more increases when a focusing operation is performed on the object at a closer object distance than when a focusing operation is performed on the object at a longer object distance.