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:
Aug. 30, 1994
Filed:
Jun. 11, 1992
John S Batchelder, Somers, NY (US);
Donald M DeCain, New York, NY (US);
Philip C Hobbs, Briarcliff Manor, NY (US);
Marc A Taubenblatt, Pleasantville, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A heterodyne interferometer is combined with darkfield surface particle detection for improved surface particle detection sensitivity. The probe beam and the reference beam have different wavelengths. The reference beam may either be a real reference beam or a virtual reference beam. The probe beam may be incident at the surface at either a grazing angle or at an angle substantially normal to the surface. The real reference beam is incident at the surface at a grazing angle. The detection may either be conventional heterodyne detection or a combination of heterodyne and Lloyd's mirror detection.