Patent ID: 8785011
Filing Date: 2014-07-22
Classification: C03C,G11B,Y10T

Abstract:
1. A glass substrate for information recording medium, which is comprised of glass comprising, denoted as molar percentages, a total of 70 to 85 percent of SiO a total of equal to or greater than 10 percent of Li equal to or greater than 5 percent of Li 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 3 percent of ZrO with a molar ratio of MgO content to CaO content (MgO/CaO) being equal to or greater than 0.14; with the molar ratio of a total content of Li which has been subjected to chemical strengthening treatment, and has a hole in the center.