Magnetic recording medium substrate and magnetic recording medium
AssigneeMitsubishi Chemical Corporation
InventorsJun Saiki, Hideo Okada, Yukihiro Miyamoto
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Abstract
A magnetic recording medium substrate comprising glass, wherein the substrate uniformly recess minute grooves having a length and a width in the range of from 0.001 to 1 μm on the whole surface and an area percentage of grooves having a length or a width exceeding 1 μm is at most 0.5% of the glass substrate.
Claims24
A magnetic recording medium substrate comprising glass, wherein the substrate surface uniformly has minute grooves having a length and a width both in the range of from 0.001 to 1 μm on the whole surface and an area percentage of grooves having a length or width exceeding 1 μm is at most 0.5% of the surface of the glass substrate.
A magnetic recording medium which comprises a glass substrate uniformly having minute grooves having a length and a width both in the range of from 0.001 to 1 μm on the whole surface of said substrate wherein an area percentage of grooves having a length or a width exceeding 1 μm is at most 0.5% of the surface of the glass substrate, and having a NiP layer, an underlayer, a magnetic layer and a protective layer provided therein in order.
A magnetic recording medium substrate comprising glass, wherein the substrate uniformly has minute grooves having a length and a width both in the range of from 0.001 to 1 μm on the whole surface and grooves having a length or a width exceeding 1 μm are present only in an amount of at most 30 pieces/10000 μm2 on the surface of the glass substrate.
A magnetic recording medium which comprises a glass substrate uniformly having minute grooves having a length and a width in the range of from 0.001 to 1 μm on the whole surface of said substrate wherein grooves having a length or a width exceeding 1 μm are present only in an amount of at most 30 pieces/10000 μm2 on the surface of the glass substrate, and having a NiP layer, an underlayer, a magnetic layer and a protective layer provided thereon in order.
A magnetic recording medium substrate comprising glass, wherein the substrate surface uniformly has minute grooves having both a length and a width in the range of form 0.001 to 1 μm and grooves having a length or a width exceeding 1 μm are present only at an area percentage of at most 0.5% and in an amount of at most 30 pieces/10000 μm2 on the surface of the glass substrate.
A magnetic recording medium which comprises a glass substrate uniformly having minute grooves having both a length and a width in the range of from 0.001 to 1 μm on the whole surface wherein grooves having a length or a width exceeding 1 μm are present only at an area percentage of at most 0.5% and in an amount of at most 30 pieces/10000 μm2 on the surface of the glass substrate, and having a NiP layer, an underlayer, a magnetic layer and a protective layer provided thereon in order.
Dependencies are inferred from the claim text.