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:
Dec. 30, 2008
Filed:
Oct. 22, 2003
Norimasa Ishii, Osaka, JP;
Kazuishi Mitani, Osaka, JP;
Yasuhiro Saito, Osaka, JP;
Koji Okuhata, Osaka, JP;
Norimasa Ishii, Osaka, JP;
Kazuishi Mitani, Osaka, JP;
Yasuhiro Saito, Osaka, JP;
Koji Okuhata, Osaka, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A glass substrate for a magnetic recording medium is formed to have a disc shape and includes ridge shaped texturesextending along concentric circles on a main surface. When measuring a 10 μm square range with an atomic force microscope, the textures have a width W that is between 10 and 200 nm. The textures have a height H that is between 2 and 10 nm. Further, the textures have a ratio (Rp/RMs) of a maximum mountain height with respect to a root mean square roughness that is less than or equal to 15. The textures include high frequency components superimposed on the low frequency components. It is preferable that the textures of the high frequency components have a width W' that is between 0.1 and 20 nm, and the textures of the high frequency components have a height H′ that is between 0.1 and 1 nm.