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:
Aug. 06, 2002
Filed:
Jun. 28, 2001
Hoya Corporation, Tokyo, JP;
Abstract
A method of producing a substrate for an information recording medium in which there is a step of washing and drying the substrate, which is also subjected to precision polishing. In the method, a correlation is preliminarily obtained between a contact angle of water on a surface of the substrate before the washing/drying step and a size (height) of protrusions attached to the surface of the substrate during the washing/drying step. The contact angle of water on the surface of the substrate before the washing/drying step is controlled so that the protrusions have a size ( ) so as not to cause a hit when at least a recording layer is formed on the surface of the substrate and when a slider provided with a recording device and/or a reproducing device is made to run on a surface of the information recording medium, and ( ) so as not to cause an error upon recording and/or reproducing the information recording medium.