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:
Dec. 15, 2020
Filed:
May. 31, 2017
Kazuyasu Ohashi, Chiba, JP;
Kazuyasu Ohashi, Chiba, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An imaging optical system includes a first lens having a concave image side surface and a negative refractive power; a second lens having a convex object side surface and a positive refractive index; a third lens having a concave object side surface and a negative refractive power; a fourth lens having a convex image side surface and a positive refractive power; and a fifth lens having a convex object side surface and a positive refractive power in the order from the object side to the image side, optionally includes a lens on the image side of the fifth lens. The imaging optical system satisfies conditional expressions [1] 1.94<n<2.20 and [2] 15.0<ν<20.0, where νand nrepresents an Abbe number and a refractive index of a lens material of the second lens Lat d-line, respectively.