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:
Jan. 04, 2011
Filed:
Jul. 29, 2009
Tomohiko Ishibashi, Utsunomiya, JP;
Tomohiko Ishibashi, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical system includes a first optical element and a second optical element on at least one of an enlargement side and a reduction side relative to a point P at which a light axis and a paraxial chief ray intersect. Each of the first optical element and second optical element is composed of a solid material having a refractive light incident surface and a refractive light emergent surface. The optical system satisfies the following conditional expressions: ΔθgF>0.0272, ΔθgF<−0.0278, and f×f<0 where ΔθgFand ΔθgFdenote anomalous partial dispersion values of the first and second optical elements for the g-line and F-line, respectively, and fand fdenote focal lengths of the first and second optical elements, respectively, when the light incident surfaces and the light emergent surfaces of the first and second optical elements are in contact with air.