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. 04, 2007
Filed:
Feb. 24, 2005
Applicant:
Akinori Ohkubo, Tochigi-ken, JP;
Inventor:
Akinori Ohkubo, Tochigi-ken, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B 9/02 (2006.01);
U.S. Cl.
CPC ...
Abstract
A point diffraction interferometer measures optical performance of a target optical system based on a light intensity distribution of an interference fringe through an interference between a wave front that passes the target optical system and a reference wave front generated from a pinhole, wherein the pinhole satisfies 1.05≦ellipticity≦1.16, where the ellipticity is defined as a diameter of a pinhole in a direction perpendicular to a linear polarization direction of light incident upon the pinhole, divided by a diameter of the pinhole in the linear polarization direction.