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. 20, 2003
Filed:
Feb. 26, 2001
Bradley Frederick Baumgartner, Los Banos, CA (US);
Andrew John Buhler, San Jose, CA (US);
Erich Chuh, San Mateo, CA (US);
Hang Fai Ngo, San Jose, CA (US);
Alma Lujan Ortega-Avery, San Jose, CA (US);
Bob C. Robinson, Hollister, CA (US);
Song How Wong-Jessel, San Jose, CA (US);
Elmer Tyree York, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A disk for a disk drive uses a circular platter having first and second sides and a circumferential edge. The circumferential edge of the disk has four symmetrically spaced apart shadows and a fifth or additional shadow that gives the disk an asymmetrical shadow signature. The fifth shadow is offset relative to the other shadows, which have congruent arcuate lengths and separation. The fifth shadow has an arcuate length that is about half as long as those of the other shadows, and is closely spaced adjacent to one of the other shadows. The asymmetric shadow signatures of the disk is used to precisely determine both the circumferential position of the platters and their planar orientation (i.e., A-side or B-side). For example, when the disk is mounted on a tool spindle and rotated, an optical detector detects the pattern of the shadows and feeds the data to a computer system. The rotational position of the spindle also is relayed to the computer for coordinating the processing of the rotating disk. When the disk is mounted on a different tool, the same shadow signature is used to determine its planar and angular positions.