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. 02, 2014
Filed:
Mar. 31, 2011
Yosuke Suzuki, Tokyo, JP;
Yosuke Suzuki, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An object of the invention is to effectively remove particles on the glass substrate surfaces, even in the case wherein abrasive particles having a small particle size is used in the polishing step of the glass substrate and a supersonic treatment is performed at a high frequency at the supersonic cleaning step after the polishing step. In a manufacturing method of a glass substrate for a magnetic disk comprising a polishing step for performing polishing of the glass substrate and a supersonic cleaning step for performing supersonic cleaning of the glass substrate after the polishing step, the polishing step uses abrasive particles having a particle size of 10 nm to 30 nm and a first supersonic cleaning is performed at a frequency of 300 kHz to 1,000 kHz to form secondary particles and then a second supersonic cleaning is performed at a frequency of 30 kHz to 100 kHz in the supersonic cleaning step.