Glass-ceramic substrate for an information storage medium
US6174827A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1999 |
| Grant date | Jan 16, 2001 |
| Priority date | — |
| Expiry date | Mar 15, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/90
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A glass-ceramic substrate for an information storage medium includes, as a predominant crystal phase, lithium disilicate (Li.sub.2 O.multidot.2SiO.sub.2) or a combination of lithium disilicate and at least one crystal phase selected from the group consisting of .alpha.-quartz (.alpha.-SiO.sub.2), .alpha.-quartz solid solution (.alpha.-SiO.sub.2 solid solution), .alpha.-cristobalite (.alpha.-SiO.sub.2) and .alpha.-cristobalite solid solution (.alpha.-SiO.sub.2 solid solution). This substrate has Young's modulus (GPa)/specific gravity of 37 or over, surface roughness Ra (arithmetic mean roughness) of 5.0 .ANG. or below, a coefficient of thermal expansion within a temperature range from -50.degree. C. to +70.degree. C. which ranges from +65.times.10.sup.-7 /.degree. C. to +130.times.10.sup.-7 /.degree. C. and bending strength of 400 MPa or over.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.