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. 07, 2019
Filed:
Mar. 04, 2015
Takahiro Nakayama, Kanagawa, JP;
Hiroshi Nakanuma, Kanagawa, JP;
Takahiro Nakayama, Kanagawa, JP;
Hiroshi Nakanuma, Kanagawa, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An imaging optical system including, in order from an object side to an image side, a first lens group having a negative refractive power, an aperture stop, a second lens group having a positive refractive power, is provided. The first lens group includes in order from the object side a first lens having a positive refractive power and a meniscus shape turning a convex surface to the object side, a second lens having a negative refractive power, and a third lens having a positive refractive power. A lens surface positioned closest to the image side in the first lens group is a concave surface to the image side, and a lens surface positioned closest to the object side in the second lens group is a concave surface to the object side.