Title:
GLASS SUBSTRATE FOR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING MEDIUM
Document Type and Number:
WIPO Patent Application WO/2017/115468
Kind Code:
A1
Abstract:
The present invention provides a glass substrate for a magnetic recording medium such that thermal cracking that is caused by dramatic temperature changes can be minimized. The glass substrate for a magnetic recording medium according to the present invention is donut shaped and includes a pair of main surfaces, an outer peripheral end surface, and an inner peripheral end surface. The outer peripheral end surface has an outer peripheral lateral surface and a pair of outer peripheral chamfers. The outer peripheral lateral surface has an arithmetic average roughness Ra of 0.1 μm or less. The outer peripheral lateral surface has an arithmetic average roughness Ra of 0.5 μm or less after being etched to 5 μm from the surface.
Inventors:
NAKAYAMA SATOSHI (JP)
Application Number:
PCT/JP2016/052541
Publication Date:
July 06, 2017
Filing Date:
January 28, 2016
Export Citation:
Assignee:
ASAHI GLASS CO LTD (JP)
International Classes:
C03C19/00; G11B5/73; G11B5/84
Domestic Patent References:
| WO2015152316A1 | 2015-10-08 |
Foreign References:
| JP2015135720A | 2015-07-27 | |||
| JP2013023420A | 2013-02-04 | |||
| JP2015060614A | 2015-03-30 | |||
| JP2006179180A | 2006-07-06 | |||
| JPH11175964A | 1999-07-02 |
Attorney, Agent or Firm:
EIKOH PATENT FIRM, P.C. (JP)
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