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:
Dec. 10, 2013
Filed:
Aug. 10, 2010
Naomi Matsumoto, Shinjuku-ku, JP;
Yoichi Hachitani, Shinjuku-ku, JP;
Kinobu Osakabe, Shinjuku-ku, JP;
Naomi Matsumoto, Shinjuku-ku, JP;
Yoichi Hachitani, Shinjuku-ku, JP;
Kinobu Osakabe, Shinjuku-ku, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An aspect of the present invention relates to glass for a magnetic recording medium substrate, which comprises, denoted as molar percentages, 50 to 75 percent of SiO, 0 to 5 percent of AlO, 0 to 3 percent of LiO, 0 to 5 percent of ZnO, a total of NaO and KO of 3 to 15 percent, a total of MgO, CaO, SrO, and BaO of 14 to 35 percent, a total of ZrO, TiO, LaO, YO, YbO, TaO, NbO, and HfOof 2 to 9 percent, with a molar ratio of {(MgO+CaO)/(MgO+CaO+SrO+BaO)} falling within a range of 0.85 to 1, and a molar ratio of {AlO/(MgO+CaO)} falling within a range of 0 to 0.30.