Magnetic disk and a glass substrate for the magnetic disk

摘要

A magnetic disk comprises a glass substrate and a magnetic layer formed on the glass substrate wherein the maximum deflection of a bent portion in the radial direction of the magnetic disk with respect to a reference length of 2 mm is 1,500 ANGSTROM or less in the entire region of a surface of the disk excluding annular areas having a width of 250 mu m which are respectively formed inwardly from annular lines at which chamfered portions formed at the inner and outer peripheries of the magnetic disk and the disk surface intersect.