Title:
MAGNETIC DISK AND SUBSTRATE FOR MAGNETIC DISK
Document Type and Number:
WIPO Patent Application WO/2023/189233
Kind Code:
A1
Abstract:
An object of the present invention to provide a magnetic disk that is flat while being thin, and is resistant to physical errors. The present invention provides a magnetic disk having a hole in the center, wherein the disk thickness is 0.60 mm or less, and where TIR measured on the circumference of different radial distances r1 (mm) and r2 (mm) in the outer peripheral region of the magnetic disk with r/R = 0.70 - 0.99, R (mm) being the disk radius and r (mm) being a radial distance measured from the disk center, is denoted by TIR1 (μm) and TIR2 (μm), respectively, a radial variation amount ΔTIR represented by an absolute value |(TIR1 - TIR2)/(r1 - r2)| of the ratio of the difference (TIR1 - TIR2) between TIR1 and TIR2 to the difference (r1 - r2) between the radial distance r1 and the radial distance r2 of the magnetic disk is 0.50 μm/mm or less.
Inventors:
KUMAGAI WATARU (JP)
HATAKEYAMA HIDEYUKI (JP)
SAKAMOTO RYO (JP)
KITAMURA NAOKI (JP)
KITAWAKI KOTARO (JP)
HATAKEYAMA HIDEYUKI (JP)
SAKAMOTO RYO (JP)
KITAMURA NAOKI (JP)
KITAWAKI KOTARO (JP)
Application Number:
PCT/JP2023/008264
Publication Date:
October 05, 2023
Filing Date:
March 06, 2023
Export Citation:
Assignee:
FURUKAWA ELECTRIC CO LTD (JP)
UACJ CORP (JP)
UACJ CORP (JP)
International Classes:
G11B5/73; G11B5/84
Domestic Patent References:
| WO2012001924A1 | 2012-01-05 | |||
| WO2011096310A1 | 2011-08-11 |
Foreign References:
| JP2013016214A | 2013-01-24 | |||
| JP2010080025A | 2010-04-08 | |||
| JP2022035634A | 2022-03-04 |
Attorney, Agent or Firm:
KURUMA Kiyoshi et al. (JP)
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