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:
Jun. 04, 2024
Filed:
Dec. 11, 2020
Hoya Corporation, Tokyo, JP;
Koichi Sato, Tokyo, JP;
Kazuaki Hashimoto, Tokyo, JP;
HOYA CORPORATION, Tokyo, JP;
Abstract
Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing apparatus, in which the total content of LiO, NaO, KO, BO, and ZnO (LiO+NaO+KO+BO+ZnO) is in a range of 0 mol % or more and 3 mol % or less, the mole ratio of the total content of AlOand MgO relative to the total content of SiOand CaO [(AlO+MgO)/(SiO+CaO)] is in a range of 0.30 or more and 0.6 or less, the total content of SiOand AlO(SiO+AlO) is in a range of 64 mol % or more and 85 mol % or less, and the total content of SiO, AlO, MgO, and CaO (SiO+AlO+MgO+CaO) is in a range of 87 mol % or more and 98 mol % or less.