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. 14, 2010
Filed:
Mar. 02, 2006
Albert Tchekanov, San Jose, CA (US);
Robert Weng, San Jose, CA (US);
E. Noel Abarra, Santa Clara, CA (US);
Michael Mallary, Sterling, MA (US);
Albert Tchekanov, San Jose, CA (US);
Robert Weng, San Jose, CA (US);
E. Noel Abarra, Santa Clara, CA (US);
Michael Mallary, Sterling, MA (US);
Seagate Technology LLC, Scotts Valley, CA (US);
Abstract
A system for reducing spike noise in a perpendicular recording medium having a soft underlayer is provided. The system radially biases the soft underlayer to substantially eliminate domain walls therein. In a first embodiment of the system, a permanent magnetic bias ring is disposed generally adjacent to the soft underlayer and a magnetic circuit is formed between the magnetic ring and the soft underlayer. Other embodiments include a concentric stationary magnetic flux return disk to extend the radial distance of the flux path. In alternative embodiments, a ferromagnetic spindle assembly is modified to produce a radiation pattern that has a net radial exterior field that biases the adjacent soft underlayer of the medium. The entire assembly can be shielded from external magnetic fields in the disk drive. Further, the shielding may operate as part of the magnetic circuit.