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:
May. 02, 2017
Filed:
Jan. 27, 2015
Kazuyasu Ohashi, Chiba, JP;
Kazuyasu Ohashi, Chiba, JP;
RICOH COMPANY, LTD., Tokyo, JP;
Abstract
A zoom lens includes, in the order starting from the object side to the side of an image plane, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power. The fourth lens group includes, in the order starting from the side closest to the image plane to the object side, a first positive lens, a first negative lens, a second negative lens and a second positive lens. The fourth lens group Ghas a configuration that satisfies the following conditional expression (1) when νdrepresents an Abbe number of the first positive lens Land νdrepresents an Abbe number of the first negative lens L−40<ν<0  (1).