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:
Apr. 10, 2001
Filed:
Dec. 30, 1998
Xuelu Zou, Tokyo, JP;
Hisayoshi Toratani, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
Disclosed is disc substrate consisting of SiO,—Al,O,—RO (RO=divalent metal) glasses having high specific elastic modulus of 36×10,Nm/kg or more or high Young's modulus of 110 GPa or more, high transition temperature of 700° C. or higher (high heat resistance), excellent surface smoothness (surface roughness Ra<5 Å) and high strength. The substrates exhibiting high specific elastic modulus or high Young's modulus and high strength enables to realize thinner magnetic discs and prevent breakdown of magnetic discs. Since glass substrates being composed of the glass have excellent heat resistance and flatness, the substrates can be subjected to heat treatment for improvement of magnetic layer characteristics and realize smaller flying height of magnetic head, i.e., higher recording density.