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. 18, 2000
Filed:
Jan. 05, 1999
Joseph P Kirk, Chelsea, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Exposures of a photosensitive material through an array of blazed gratings illuminate a lens asymmetrically to detect effects of a plurality of azimuthal aberrations including coma, astigmatism, and three-leaf and four-leaf clover aberrations. A plurality of such exposures of the array of blazed gratings at slightly differing focus allows detection of focus shift due to any aberrations present in the lens. Upon development of the plurality of exposures, contrast of each area is measured, for example, by reflection or scattering from the relief in the developed photosensitive material and the aberrations thus detected can be simulated by effective summation of individual aberration effects.