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. 03, 2017
Filed:
Nov. 23, 2012
Engineering Synthesis Design, Inc., Tucson, AZ (US);
Piotr Szwaykowski, Glendale, CA (US);
Raymond J. Castonguay, Tucson, AZ (US);
Other;
Abstract
Polarization based interferometric methods suffer from errors caused by the internal instrument birefringence. Disclosed herein are methods for using dual interferometric measurements allow separating the influence of instrument errors (e.g., due to geometry and birefringence errors) and the measured part. The interferometric system error in an interferometry system having two light sources orthogonally polarized with respect to each other wherein each light source reflects from a reference surface and a test surface, creating four reflected beams (Wr, Vr, Wt, Vt), may be determined by performing a first interference measurement (M) from Wr-Vt. A second interference measurement (M) from Wt-Vr is performed and a third measurement (M), indicative of the interferometric system error, is calculated by averaging the first and second measurements ([M+M]/2).