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:
May. 07, 2002
Filed:
Aug. 19, 1999
Applicant:
Inventors:
Assignee:
Hoya Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C03C 1/700 ;
U.S. Cl.
CPC ...
C03C 1/700 ;
Abstract
In a glass substrate for use in a magnetic recording medium, a surface roughness of at least a principal surface of the glass substrate is measured by the use of the interatomic force microscope (AFM), Ra falls within the range between 0.2 and 2.5 nm, Rmax falls within the range between 3 and 25 nm, and Rmax/Ra falls within the range between 3 and 35.