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:
Apr. 03, 2007
Filed:
Apr. 04, 2002
Nathan Ellis Jacobson, Rochester, MN (US);
Terry Lee Jensen, Rochester, MN (US);
Rick Allan Sprague, San Jose, CA (US);
Nathan Ellis Jacobson, Rochester, MN (US);
Terry Lee Jensen, Rochester, MN (US);
Rick Allan Sprague, San Jose, CA (US);
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
A salt mixture used for chemical strengthening of data recording disks is subjected to sub-micron filtration prior to use to remove certain impurities. Preferably, glass disks are chemically strengthened by ion exchange in a bath of molten sodium nitrate and potassium nitrate. A salt fresh mixture is prepared by starting with high-grade bulk salt in the intended proportions, melting the salt, and filtering the salt in a stainless steel filter, which is preferably approximately 2 micron or smaller. Filtration removes trace amounts of certain contaminants. The salt mixture thus prepared is then used for chemical strengthening of disks in the conventional manner.