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:
Nov. 30, 1999
Filed:
Jul. 08, 1997
John B Hayes, Tucson, AZ (US);
Wyko Corporation, Tucson, AZ (US);
Abstract
An optical crossed grating is used to calibrate a conventional autocollimator operated with a single-frequency light source. Since a collimated monochromatic beam is diffracted at a number of well known angles after being reflected from the grating, an array of spots is formed on the detector surface that makes it possible to calibrate the autocollimator in a single operation. Because the angle of the diffracted light is determined only by the spacing in the grid, the calibration accuracy is insensitive to temperature variations and to the position of the grid on the sample stage. The calibration scaling values are calculated simply by measuring the spot spacings on the detector surface in relation to the diffraction angles corresponding to the grid spacing.