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:
Feb. 28, 2012
Filed:
May. 29, 2009
Applicants:
Shinpei Todo, Tokyo, JP;
Yasuhiro Naka, Tokyo, JP;
Inventors:
Shinpei Todo, Tokyo, JP;
Yasuhiro Naka, Tokyo, JP;
Assignee:
The Furukawa Electric Co., Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 5/70 (2006.01); B24B 1/00 (2006.01); C09K 3/14 (2006.01);
U.S. Cl.
CPC ...
Abstract
There is provided a glass substrate for a magnetic disk in which a maximum height of bumps forming a roughness pattern at a period of smaller than 2 μm is 6 nm or lower in an annular area having a width of 30 μm on a main surface on which a magnetic recording area is formed, a number of bumps having a height of 3 nm or higher in a unit area having a circular arc length of 30 μm within the annular area is one or less, and a difference in arithmetic average roughness between unit areas within the annular area is 0.2 nm or smaller.