| 摘要 |
PURPOSE:To enable a floppy disc to withstand the severe environmental conditions by specifying the relation between the thickness and the tensile elastic modulus of a metallic foil as well as the thickness and the tensile elastic modulus of a plastic film. CONSTITUTION:The inequalities 1-4 are satisfied, where a metallic foil has the Tm(mm) thickness and a YMm(kg/mm<2>) tensile elastic modulus and a plastic film has the Tf(mm) thickness and a YMf(kg/mm<2>) tensile elastic modulus respectively. The value Tm.YMm/Tf.Mf of the equation 1 depends on the size stability and rigidity of a substrate. The size stability is improved higher to the change of the temperature and the humidity as said value of the inequalities 1 is higher. Furthermore the substrate rigidity is also improved. The Tm.YMm of the inequality 2 affects greatly the substrate rigidity and has the relation with the follow-up performance of a head. The thickness Tm and Tf are mainly subject to the recovery properties and the shock resistance of the substrate. The Tf should be decided from the relation between the metallic foil and a magnetic layer put on the plastic film.
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