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:
Jan. 14, 2025
Filed:
Feb. 07, 2023
Applicant:
Showa Denko K.k., Tokyo, JP;
Inventors:
Assignee:
RESONAC HARD DISK CORPORATION, Chiba, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 5/73 (2006.01); G11B 5/82 (2006.01); G11B 5/84 (2006.01);
U.S. Cl.
CPC ...
G11B 5/73921 (2019.05); G11B 5/82 (2013.01); G11B 5/8404 (2013.01);
Abstract
A dummy substrate is formed with a disk-shaped glass substrate having a center hole, and a magnetic recording film on an outer circumferential surface along a thickness direction of the glass substrate and an inner circumferential surface of the center hole, and a surface roughness (Ra) of one surface and the other surface of the glass substrate is in a range of 0.2 nm or more and 100 nm or less.