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:
Oct. 20, 2015
Filed:
Jun. 27, 2014
Canon Kabushiki Kaisha, Tokyo, JP;
Hiroto Yasui, Saitama, JP;
CANON KABUSHIKI KAISHA, , JP;
Abstract
The optical system includes, in order from an object side, a front lens unit LF, an aperture stop S, a rear lens unit LR. The front lens unit includes a diffraction optical element Ldoe. A stop side positive lens Lsp disposed closest to the aperture stop among the rear lens unit satisfies 1.55≦Nd≦1.70, 30.0≦νd≦50.0, and 5.0×10≦ΔθdC≦5.0×10. Ndand νdrepectively represent a refractive index and an Abbe number of the stop side positive lens for a d-line, and ΔθdCis represents a value defined by ΔθdC=θdC−(−0.17041×θgd+0.513577) where Ng, NCand NFrespectively represent refractive indices of the stop side positive lens for a g-line, a C-line and an F-line. θdCand θgdare respectively defined by θdC=(Nd−NC)/(NF−NC) and θgd=(Ng−Nd)/(NF−NC).