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:
May. 25, 2004
Filed:
Oct. 24, 2001
Applicant:
Inventors:
Jianmin Wang, Fremont, CA (US);
Jason L. Pressesky, Menlo Park, CA (US);
Assignee:
Seagate Technology LLC, Scotts Valley, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B 9/07 ;
U.S. Cl.
CPC ...
G01B 9/07 ;
Abstract
A method and apparatus for interferometnc measurement of a medium surface is disclosed. More particularly, a quadrature phase shift interferometer and a process for unwrapping phase are described. The interferometer has a reduced number of optical components though yields results sufficient to measure surface of a hard disc for final inspection. Defects on such a surface are characterized by their out-of-plane displacement with nanometer resolution.