Glass for use as substrate for information recording medium, substrate for information recording medium and information recording medium, and their production methods

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United States of America Patent

PATENT NO 8785011
APP PUB NO 20120328907A1
SERIAL NO

13605006

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ATTORNEY / AGENT: (SPONSORED)

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Abstract

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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, La2O3 Y2O3 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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Patent Owner(s)

  • HOYA CORPORATION

International Classification(s)

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Hachitani, Yoichi Tokyo, JP 29 468
Ikenishi, Mikio Tokyo, JP 45 654
Osakabe, Kinobu Tokyo, JP 36 543
Tachiwana, Kazuo Tokyo, JP 20 268
Zou, Xuelu Tokyo, JP 89 1513

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