Magnetic disc substrate and a magnetic disc using the same

摘要

Using a thermoplastic norbornene type plastic as a material for the magnetic disc substrate, a magnetic disc substrate having a small deformation and a high modulus of elasticity is prepared. By optimizing the thickness of the substrate, the resonance frequency of the magnetic disc can be elevated to a level higher than the servo band. As a result, a magnetic disc substrate can form a servo mark having a high positional precision, and can carry out tracking with high precision.