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. 19, 2002
Filed:
Sep. 14, 1999
Louis J. Fioravanti, Boulder, CO (US);
Kent D. Dillin, Yukon, OK (US);
Seagate Technology LLC, Scotts Valley, CA (US);
Abstract
A method for evaluating head flight characteristics in a disc drive includes accelerating a disc to an initial rotational velocity sufficient to aerodynamically support a head over the disc at a nominal flying height. A read bias current is applied to the head to generate a readback signal determined in relation to the voltage drop across the head. A thermal asperity threshold level is applied which the readback signal exceeds in response to contact between the head and the disc as the disc rotates. A head touchdown velocity is determined by decelerating the disc to decrease the flying height of the head and detecting subsequent contact between the head and the disc when the readback signal exceeds the thermal asperity threshold level. A head take off velocity is similarly determined by monitoring the head readback signal as the disc is accelerated and lifts off the disc.