GLASS SUBSTRATE FOR HARD DISK AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a glass substrate for a hard disk whose outer circumferential edge face is fully polished to a mirror plane, and to provide a method for easily manufacturing the same at a low cost. SOLUTION: The glass substrate for a hard disk is free of outer circumferential finishing. Without control of the outer circumferential edge face, the method for manufacturing glass substrates for a hard disk free of outer circumferential finishing comprises a press molding treatment of a glass between the upper and the lower molds, a crystallization or annealing treatment, a centroid coring treatment for forming a central hole with a center of gravity, the first lapping treatment, a precision working treatment of the inner circumferential edge face, a polishing treatment of the inner circumferential edge face, the second lapping treatment, a polishing treatment, and a washing treatment.