Patent ID: 6327874
Filing Date: 2001-12-11
Classification: G11B,Y10S,Y10T

Abstract:
A method for manufacturing a glass-ceramic substrate for a magnetic information storage medium having a data zone and a landing zone comprising steps of:melting a base glass and forming the molten glass into a desired shape;subjecting the formed glass to heat treatment for producing a crystal nucleus;further subjecting the formed glass to heat treatment for crystallization;polishing the surface of the glass to a surface roughness (Ra) within a range from 3 .ANG. to 9 .ANG.; andforming in the landing zone a multiplicity of projections or depressions having a uniform shape by irradiation of laser beam, said projections or depressions having a height within a range of 50 .ANG. to 300 .ANG. and a surface roughness (Ra) within a range from 10 .ANG. to 50 .ANG..