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. 21, 2015
Filed:
Jan. 06, 2014
Canon Kabushiki Kaisha, Tokyo, JP;
Kazuhiro Inoko, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In an optical system including a front lens unit having negative refractive power, a stop, and a rear lens unit having positive refractive power in order from an enlargement side to a reduction side, the front lens unit has a combination lens in which a negative lens and a positive lens are adjacently arranged in order from the enlargement side to the reduction side, and a focal length of the negative lens f, an Abbe number νand relative partial dispersion θof a material of the negative lens, an Abbe number νand relative partial dispersion θof a material of the positive lens, and a focal length of the entire optical system fare appropriately set.