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:
Mar. 24, 2015
Filed:
Jul. 09, 2012
Toshio Takizawa, Tokyo, JP;
Kraisorn Phandon, Amphur Muang, TH;
Kenichi Nishimori, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Hoya Glass Disk (Thailand) Ltd., Lamphun, TH;
Abstract
It is an object to provide a magnetic disk substrate highly reliable to prevent the occurrence of crash failure even if a magnetic disk is rotated at high speed, and suitable for a hard disk that starts and stops by the load/unload method, and a magnetic disk using such a substrate. The representative structure of a magnetic disk substrate is a disk-shaped glass substratehaving a generally flat main surface, an end face, a chamfered faceformed between the main surfaceand the end face, and an offset portion, at the periphery of the main surface, raised or lowered with respect to a flat surface, other than the periphery, of the main surface, and characterized in that the magnitude of the offset portion is approximately uniform over the entire circumference of the glass substrate