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:
Mar. 14, 2000
Filed:
Aug. 10, 1998
Kimiaki Nakazawa, Kitakatushika, JP;
Fuji Photo Optical Co., Ltd., Omiya, JP;
Abstract
A super wide angle lens, having a viewing angle greater than 120 degrees, and an F-number of about 1.2 is disclosed. The lens is formed of a first lens group G.sub.1 of negative refractive power, a second lens group G.sub.2 of positive refractive power, and a third lens group G.sub.3 of positive refractive power. The lens is designed so that the lens elements used in the lens groups may be easily and economically manufactured. The first lens group has a first lens element L.sub.1 composed of a negative meniscus lens with its convex surface on the object side, and a second lens element L.sub.2 composed of a negative meniscus lens with its convex surface on the object side. The second lens group includes a third lens element L.sub.3, that is biconcave, cemented to a fourth lens element L.sub.4 that is biconvex. The third lens group has four lens elements: a fifth lens element L.sub.5 composed of a negative meniscus lens, with its convex surface on the object side; a sixth lens element L.sub.6 composed of a biconvex lens cemented to the fifth lens element; a seventh lens element L.sub.7 composed of a negative meniscus lens, with its convex surface on the object side; and an eighth lens element L.sub.8 composed of a biconvex lens cemented to the seventh lens element.