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. 20, 2007
Filed:
Mar. 01, 2007
Tatsumaro Yamashita, Miyagi-ken, JP;
Eiki Matsuo, Nagano-ken, JP;
Tatsumaro Yamashita, Miyagi-ken, JP;
Eiki Matsuo, Nagano-ken, JP;
Alps Electric Co., Ltd., Tokyo, JP;
Abstract
A front group is formed of a negative first lens as a meniscus lens which is convex at the object side and a negative second lens, and a rear group is formed of a biconvex positive third lens, an aperture stop, a negative fourth lens and a biconvex positive fifth lens. The first lens is a glass lens, and the second lens is a plastic aspherical lens. The following conditions are satisfied: −2.4<fI/f<−1.55, 0.15<f2/f1<0.35, va<29, and vb>50, where f denotes a focal distance of a whole system, f1 denotes a focal distance of the first lens, f2 denotes a focal distance of the second lens, fI denotes a focal distance of the front group, va denotes an average value of abbe numbers of the third and the forth lenses, and vb denotes an average value of abbe numbers of the rest of the lenses.