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, 1998
Filed:
Sep. 30, 1997
Kenji Morinaga, Nakagawa-machi, JP;
Yuji Akimoto, Fukuoka, JP;
Fumiyuki Shimizu, Chikushino, JP;
Mineto Iwasaki, Tosu, JP;
Naoto Shindo, Ohnojo, JP;
Sec Inc., Tokyo, JP;
Abstract
A crystallized glass for a substrate of an information-recording disk, which has been obtained by melting a glass forming material consisting essentially of, in wt. % as oxide, 55 to 85% of SiO.sub.2, 5 to 20% of Li.sub.2 O, 0 to 10% of K.sub.2 O+Na.sub.2 O, 0 to 10% of MgO, 0 to 20% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 10% of ZnO, 0 to 10% of Al.sub.2 O.sub.3, 0 to 15% of B.sub.2 O.sub.3, 0 to 6% of P.sub.2 O.sub.5, 0 to 3% of TiO.sub.2, 0 to 3% of ZrO.sub.2, 0 to 3% of SnO.sub.2 and 0 to 1% of As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3, 0.1 to 10 wt. % of F and 0.1 to 20 wt. % of Cl, molding, vitrifying and crystallizing the material, and which contains at least 0.05% by weight of chlorine after crystallization. The glass forming material may further contain 0 to 10% of Fe.sub.2 O.sub.3, 0 to 10% of Cr.sub.2 O.sub.3, 0 to 10% of NiO, 0 to 10% of V.sub.2 O.sub.5, 0 to 10% of CuO, 0 to 10% of MnO.sub.2, 0 to 10% of MoO.sub.3, the total of Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3 +NiO+V.sub.2 O.sub.5 +CuO+MnO.sub.2 +MoO.sub.3 being 0.5 to 10%, and 0 to 3% of CeO.sub.2. The crystallized glass has a microcrystalline structure and surface properties desirable as a substrate material for an information-recording disk as well as excellent meltability and moldability.