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:
Jan. 06, 2015
Filed:
Mar. 31, 2011
Takuhiro Hirakawa, Shinjuku-ku, JP;
Yasunari Hirano, Shinjuku-ku, JP;
Kouichi Tamoto, Shinjuku-ku, JP;
Tomoyuki Yamaguchi, Shinjuku-ku, JP;
Takuhiro Hirakawa, Shinjuku-ku, JP;
Yasunari Hirano, Shinjuku-ku, JP;
Kouichi Tamoto, Shinjuku-ku, JP;
Tomoyuki Yamaguchi, Shinjuku-ku, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An object of the invention is to remove effectively metallic contaminants adhering to the glass substrate surfaces without increasing roughness of the glass substrate surfaces in the glass substrate for a magnetic disk. In a manufacturing method of a glass substrate for a magnetic disk, a cleaning step comprising a treatment of contacting the glass substrate with a cleaning liquid containing peroxodisulfate and having a pH of not less than 2 and not more than 4 is appended. In addition, an example of the cleaning liquid can be prepared by adding sodium peroxodisulfate to an acidic solution.