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. 07, 2010
Filed:
Mar. 15, 2010
Miwako Yoshida, Yokohama, JP;
Miwako Yoshida, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An objective lens OL includes, in order from an object, a first lens group Ghaving positive refractive power, a second lens group Ghaving positive refractive power, a diffractive optical element GD forming a diffractive optical surface D thereon, and a third lens group Ghaving negative refractive power. The first lens group Gincludes at least one cemented lens and the most object side surface thereof forms a concave surface facing the object. The second lens group Gincludes at least one cemented lens. The third lens group Gincludes at least one cemented negative lens. In the objective lens OL, a principal ray crosses an optical axis between the second lens group Gand the third lens group G, and in the diffractive optical element GD, the diffractive optical surface D is disposed in the vicinity of the position where the principal ray crosses the optical axis.