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. 08, 2003
Filed:
Mar. 29, 2000
Applicant:
Inventor:
Nobuyuki Eto, Tokyo, JP;
Assignee:
Hoya Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 2/1302 ;
U.S. Cl.
CPC ...
H01L 2/1302 ;
Abstract
On manufacturing a glass substrate for an information recording medium, after a principal surface of the glass substrate is polished, sulfuric acid-cleaning of the principal surface is carried out so that the glass substrate has surface roughnesses Ra and Rmax satisfying Ra=0.1-0.7 nm and Rmax/Ra<20 as measured by an inter-atomic force microscope (AFM), where Ra is representative of a center-line-mean roughness and where Rmax is defined as a maximum height representative of a difference between a highest point and a lowest point.