Magnetic disk comprising a flexible substrate and a plastic film each having a specified Young's modulus and which meet specified thickness relationships

摘要

A magnetic disk comprising an annular flexible substrate and a magnetic layer on at least one substrate major surface is provided with a plastic film ring or a pair of plastic film rings along the outer periphery of the disk. The ring is adhesively secured to the disk on the substrate major surface. The ring thickness is controlled to a specific range relative to the substrate thickness, presenting a magnetic disk featuring stable operation and a minimized output variation.