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:
Sep. 25, 2001
Filed:
Dec. 03, 1992
Andrei Brunfeld, Bay-Yam, IL;
Joseph Shamir, Haifa, IL;
Gregory Toker, Jerusalem, IL;
Liviu Singher, Haifa, IL;
Ilan Laver, Kefau Saba, IL;
Ely Pekel, Kefau Saba, IL;
Brown & Sharpe Surface Inspection Systems, Inc., North Kingstown, RI (US);
Abstract
An optical inspection apparatus operates at high speed at very high resolution for detecting defects in transparent disks in a production environment. These transparent disks are of the type commonly used as disk platters in hard disk drives. This apparatus uses a laser beam directed to a polygon scanner, which provides a linear scan of the beam along a radius of the disk. The disk to be inspected is rotated such that its entire surface passes the scan path of the laser beam. The laser beam, after passing through the unit to be inspected, is directed to a parallel detector array, which detects changes in the nominal Gaussian distribution of the laser beam that correspond to defects in the surface of the transparent disk above a programmable threshold level. This parallel detection method allows the inspection apparatus to identify defects much smaller than the diffraction limits of the optics used, and will accurately identify changes of the laser beam caused by defects in the disk. An automatic disk handler loads untested disks into the apparatus and unloads and sorts tested disks according to the results of the inspection.