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. 03, 2023
Filed:
May. 07, 2021
Hoya Corporation, Tokyo, JP;
Kinobu Osakabe, Tokorozawa, JP;
HOYA CORPORATION, Tokyo, JP;
Abstract
A non magnetic substrate for a magnetic disk includes a substrate main body having two opposing main surfaces and being a glass substrate main body or an aluminum alloy substrate main body, and a metal film made of an Ni—P alloy and provided on the main surfaces and an outer circumferential edge surface of the substrate main body. The non magnetic substrate has a thickness (T+D) of 0.57 mm or less, which is the sum of a thickness T of the substrate main body and a thickness D of the metal film. The non magnetic substrate has a diameter of 90 mm or more. A ratio D/T is 0.025 or more. The outer circumferential edge surface of the substrate main body forming an interface with the metal film has a surface roughness maximum height Rz of 0.5 μm or more.