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. 28, 1995
Filed:
May. 20, 1994
Chiayu Ai, Tucson, AZ (US);
Paul J Caber, Tucson, AZ (US);
Wyko Corporation, Tucson, AZ (US);
Abstract
Interferometric apparatus that combines white-light VSI and single-wavelength PSI capabilities to improve the accuracy of height measurements in steep regions and in areas with large inter-pixel steps on the test surface. The technique consists of performing VSI measurements to obtain a relatively coarse profile of the test surface and to identify regions separated by a large step. Then PSI measurements are carried out over the test surface to obtain a relatively fine profile. Offsets between VSI and PSI measurements are calculated to correct for misalignments and phase shifts that may have occurred between the two sets of measurements. Finally, the fine PSI data are integrated to within one quarter wavelength of the coarse VSI data. The resulting quality of the height data in each of the step regions is thus improved to within the resolution of the PSI measurements.