Title:
磁気ディスク用非磁性基板及び磁気ディスク
Document Type and Number:
Japanese Patent JP6574537
Kind Code:
B2
Abstract:
A substrate for a magnetic disk includes a substrate main body having a disk shape and an alloy film. The substrate has a thickness (T+D) of 0.520 mm or less, which is the sum of a thickness T of the substrate main body and a thickness D of the film formed on main surfaces of the substrate main body. The disk shape has an outer diameter of 90 mm or more. A ratio D/T of the thickness D to the thickness T is 0.025 or more. The thickness of the film formed on an outer circumferential edge surface of the substrate main body is greater than the thickness of the film formed on each of the main surfaces, and the thickness of the film formed on each of the main surfaces is 80% or more of the thickness of the film formed on the outer circumferential edge surface.
Inventors:
Koshisakabe Motonobu
Application Number:
JP2019509441A
Publication Date:
September 11, 2019
Filing Date:
April 02, 2018
Export Citation:
Assignee:
HOYA CORPORATION
International Classes:
G11B5/73; G11B5/82
Domestic Patent References:
| JP7057233A | ||||
| JP2005346880A | ||||
| JP2005322364A | ||||
| JP2009160831A | ||||
| JP2006085887A | ||||
| JP2006260700A |
Attorney, Agent or Firm:
Global IP Tokyo Patent Business Corporation