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. 18, 2021
Filed:
Nov. 30, 2017
Yoshifumi Sudoh, Wako, JP;
Yoshifumi Sudoh, Wako, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An image forming lens includes a first lens group and a second lens group. The first lens group has positive refractive power moved toward the object side when focusing from a long distance to a short distance. The second lens group has positive refractive power arranged closer to the image side than the first lens group. The second lens group includes, in order from the object side to the image side, a negative lens having a concave surface on the image side, a negative meniscus lens having a concave surface on the object side, and a positive lens. The focal length fof the negative lens and the focal length fof the negative meniscus lens satisfy the following conditional expression: (1) 0.1<f/f<0.5.