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. 11, 2007
Filed:
May. 04, 2005
Nobutaka Minefuji, Saitama, JP;
Nobutaka Minefuji, Saitama, JP;
PENTAX Corporation, Tokyo, JP;
Abstract
An imaging optical system includes an aperture stop, a positive first lens group, and a positive or negative second lens group. The first lens group includes a positive first lens element and a negative second lens element. The first lens element is provided with an aspherical surface on the object-side surface thereof. The aspherical surface is formed so that the higher a height from the optical axis in a radial direction becomes the more an aspherical surface at the height is displaced toward the object, compared with a paraxial spherical surface. The second lens group includes a meniscus third lens element. The meniscus third lens element is provided with an aspherical surface on each lens surface thereof, and has the convex surface facing toward the object in the vicinity of the optical axis.