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:
Jan. 16, 2001
Filed:
Mar. 15, 1999
Kabushiki Kaisha Ohara, , JP;
Abstract
A glass-ceramic substrate for an information storage medium includes, as a predominant crystal phase, lithium disilicate (Li,O·2SiO,) or a combination of lithium disilicate and at least one crystal phase selected from the group consisting of &agr;-quartz (&agr;-SiO,), &agr;-quartz solid solution (&agr;-SiO,solid solution), &agr;-cristobalite (&agr;-SiO,) and &agr;-cristobalite solid solution (&agr;-SiO,solid solution). This substrate has Young's modulus (GPa)/specific gravity of 37 or over, surface roughness Ra (arithmetic mean roughness) of 5.0 Å or below, a coefficient of thermal expansion within a temperature range from −50° C. to +70° C. which ranges from +65×10,/° C. to +130×10,/° C. and bending strength of 400 MPa or over.