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:
Jan. 30, 2024
Filed:
Aug. 24, 2022
Applicant:
Hoya Corporation, Tokyo, JP;
Inventors:
Koichi Sato, Tokyo, JP;
Kazuaki Hashimoto, Tokyo, JP;
Assignee:
HOYA CORPORATION, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C03C 3/091 (2006.01); G11B 5/73 (2006.01); C03C 3/078 (2006.01); C03C 3/083 (2006.01); C03C 3/087 (2006.01); C03C 3/093 (2006.01); C03C 3/095 (2006.01);
U.S. Cl.
CPC ...
C03C 3/091 (2013.01); C03C 3/078 (2013.01); C03C 3/083 (2013.01); C03C 3/087 (2013.01); C03C 3/093 (2013.01); C03C 3/095 (2013.01); G11B 5/73921 (2019.05);
Abstract
A glass, which is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording and reproducing apparatus, is an amorphous oxide glass. An SiOcontent ranges from 56 mol % to 80 mol %, an LiO content ranges from 1 mol % to 10 mol %, a BOcontent ranges from 0 mol % to 4 mol %, a NaO content is 0 mol %, a total content of MgO and CaO (MgO+CaO) ranges from 9 mol % to 40 mol %, and the oxide glass has a specific gravity of 2.75 g/cmor less, a glass transition temperature of 650° C. or higher, and a Young's modulus of 90 GPa or more.