- Patent Title: Glass for magnetic recording medium substrate, magnetic recording medium substrate, magnetic recording medium, glass spacer for magnetic recording and reproducing apparatus, and magnetic recording and reproducing apparatus
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Application No.: US17629002Application Date: 2020-07-22
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Publication No.: US11688424B2Publication Date: 2023-06-27
- Inventor: Koichi Sato , Kazuaki Hashimoto
- Applicant: HOYA CORPORATION
- Applicant Address: JP Tokyo
- Assignee: HOYA CORPORATION
- Current Assignee: HOYA CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Global IP Counselors, LLP
- Priority: JP 19134578 2019.07.22 JP 19205993 2019.11.14
- International Application: PCT/JP2020/028450 2020.07.22
- International Announcement: WO2021/015240A 2021.01.28
- Date entered country: 2022-01-21
- Main IPC: G11B5/73
- IPC: G11B5/73 ; C03C3/087
Abstract:
Provided is a glass for a magnetic recording medium substrate, which is an amorphous glass, in which an SiO2 content is in a range of 54 mol % or more and 62 mol % or less, an MgO content is in a range of 15 mol % or more and 28 mol % or less, an Li2O content is in a range of 0.2 mol % or more, and an Na2O content is in a range of 5 mol % or less.
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