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:
Apr. 14, 2015
Filed:
Jul. 25, 2014
Applicant:
Hoya Corporation, Tokyo, JP;
Inventors:
Naomi Matsumoto, Shinjuku-ku, JP;
Kazuaki Hashimoto, Shinjuku-ku, JP;
Assignee:
Hoya Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 11/00 (2006.01); G11B 5/62 (2006.01); G11B 5/73 (2006.01); C03C 3/085 (2006.01); C03C 3/087 (2006.01); C03C 17/06 (2006.01); C03C 21/00 (2006.01); G11B 5/84 (2006.01); G11B 13/04 (2006.01); G11B 5/00 (2006.01);
U.S. Cl.
CPC ...
G11B 5/7315 (2013.01); C03C 3/085 (2013.01); C03C 3/087 (2013.01); C03C 17/06 (2013.01); C03C 21/00 (2013.01); G11B 5/73 (2013.01); G11B 5/8404 (2013.01); G11B 13/04 (2013.01); G11B 2005/0021 (2013.01);
Abstract
An aspect of the present invention relates to glass for a magnetic recording medium substrate, which includes essential components in the form of SiO, LiO, NaO, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO, wherein a molar ratio of a content of MgO to a combined content of MgO, CaO, SrO, and BaO (MgO/(MgO+CaO+SrO+BaO)) is equal to or greater than 0.80, and which has a Young's modulus of equal to or greater than 80 GPa, and a glass transition temperature of equal to or greater than 620° C.