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:
Sep. 08, 2020
Filed:
Apr. 04, 2018
Agc Inc., Chiyoda-ku, JP;
Eriko Maeda, Tokyo, JP;
Hiroyuki Hijiya, Tokyo, JP;
Kensuke Nagai, Tokyo, JP;
Tetsuya Nakashima, Tokyo, JP;
Yutaka Kuroiwa, Tokyo, JP;
AGC Inc., Chiyoda-ku, JP;
Abstract
The present invention pertains to a glass for a data storage medium substrate which contains a specific amount of each of SiO, AlO, MgO, CaO, SrO, BaO, LiO, NaO, and KO, in molar percentage based on the oxides, and does not substantially contain BOor ZrO, wherein the sum of the LiO, NaO, and KO contents (RO), the molar ratio of the SiOcontent to the AlOcontent (SiO/AlO), and the molar ratio of the sum of the SiOand AlOcontents (SiO+AlO) to RO[(SiO+AlO)/RO] fall within their specific ranges, formula (1): 90<[SiO]+2×[AlO]+0.8×[RO]−0.5×[RO] [in formula (1), RO represents the sum of the MgO, CaO, SrO, and BaO contents] is satisfied, and the glass transition point T, the alkali resistance, and the acid resistance fall within their specific ranges.