Invention Grant
- Patent Title: Glass for use in substrate for information recording medium, substrate for information recording medium and information recording medium, and their manufacturing method
- Patent Title (中): 用于信息记录介质的基板,信息记录介质用基板和信息记录介质的玻璃及其制造方法
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Application No.: US13244399Application Date: 2011-09-24
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Publication No.: US08357459B2Publication Date: 2013-01-22
- Inventor: Kazuo Tachiwana , Yoichi Hachitani , Xuelu Zou , Mikio Ikenishi , Kinobu Osakabe
- Applicant: Kazuo Tachiwana , Yoichi Hachitani , Xuelu Zou , Mikio Ikenishi , Kinobu Osakabe
- Applicant Address: JP Tokyo
- Assignee: Hoya Corporation
- Current Assignee: Hoya Corporation
- Current Assignee Address: JP Tokyo
- Agency: Sughrue Mion, PLLC
- Priority: JP2006-159223 20060608
- Main IPC: C03C3/097
- IPC: C03C3/097 ; C03C3/04

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 SiO2 and Al2O3, where SiO2 content is equal to or greater than 50 percent and Al2O3 content is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of Li2O, Na2O and K2O; 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 ZrO2, HfO2, Nb2O5, Ta2O5, La2O3Y2O3 and TiO2; with the molar ratio of the total content of Li2O, Na2O and K2O to the total content of SiO2, Al2O3, ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2((Li2O+Na2O+K2O)/(SiO2+Al2O3+ZrO2+HfO2+Nb2O5+Ta2O5+La2O3+Y2O3+TiO2)) 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.
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