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:
Jul. 29, 2014
Filed:
Sep. 20, 2011
Hiroto Yasui, Saitama, JP;
Hiroto Yasui, Saitama, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
The optical system includes plural lens groups, a negative lens included in one lens group among the plural lens groups and formed of a first medium, a diffractive grating formed on at least one lens surface of the negative lens and being in contact with a second medium different from the first medium, and a positive lens included in the one lens group and formed of a third medium different from the first medium and the second medium. The first medium satisfies ndA≧1.7 and 40≦νdA≦55 where ndA represents a refractive index of the first medium for a d-line, and νdA represents an Abbe number of the first medium for the d-line. The third medium satisfies ndC≦1.55 and νdC≧60 where ndC represents a refractive index of the third medium for the d-line, and νdC represents an Abbe number of the third medium for the d-line.