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. 12, 2016
Filed:
Jun. 17, 2014
Hoya Corporation, Tokyo, JP;
Kazuo Tachiwana, Tokyo, JP;
Yoichi Hachitani, Tokyo, JP;
Xuelu Zou, Tokyo, JP;
Mikio Ikenishi, Tokyo, JP;
Kinobu Osakabe, Tokyo, JP;
HOYA CORPORATION, Tokyo, JP;
Abstract
According to one aspect of the present invention, provided is glass for use in substrate for information recording medium, which comprises, denoted as molar percentages, a total of 70 to 85 percent of SiOand AlO, where SiOcontent is equal to or greater than 50 percent and AlOcontent is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of LiO, NaO and KO; a total of 1 to 6 percent of CaO and MgO, where CaO content is greater than MgO content; a total of greater than 0 percent but equal to or lower than 4 percent of ZrO, HfO, NbO, TaO, LaOYOand TiO; with the molar ratio of the total content of LiO, NaO and KO to the total content of SiO, AlO, ZrO, HfO, NbO, TaO, LaO, YOand TiO((LiO+NaO+KO)/(SiO+AlO+ZrO+HfO+NbO+TaO+LaO+YO+TiO)) being equal to or less than 0.28. Further provided are the substrate for information recording medium, information recording medium and their manufacturing methods according to the present invention.