| 摘要 |
PURPOSE:To obtain a flexible magnetic disc adaptable to practical use by controlling the thicknesses of a base film and magnetic layer optimum for a disc from the relation among running stability, reproduced output, durability, etc. CONSTITUTION:A thin ferromagnetic metallic film having (b)mum thickness per surface is formed on both surfaces of a base consisting of an arom. polyamide high polymer film and having (a)mum thickness in such a way that (a), (b) thereof satisfy the equation I . Thin magnetic films are formed on both surfaces of such base film by a method such as vapor deposition or sputtering, etc. of a ferromagnetic metal such as Co-Cr, Co-Ni, Co or the like. The thickness (a) of the base film and the thickness (b) of the thin magnetic film are so determined that the conditions in the hatched frame shown in the figure are satisfied. The magnetic disc having the extremely good characteristic with respect to the envelope of the reproduced output, rotative running stability and durability is thus produced. |
