MAGNETIC DISK GLASS SUBSTRATE, MAGNETIC DISK, AND MAGNETIC DISK MANUFACTURING METHOD

摘要

Of the surface shapes of two individual regions selected arbitrarily on the surface of a glass substrate closer to the central portion than an outer circumference end, the surface shape having a shape wavelength of a band of 60 to 500 µm is extracted. Provided is a magnetic disk glass substrate, in which the difference of a fine swell (Rq) of that region is 0.02 nm or less or in which the difference of the standard deviation of the fine swell (Rq) of that region is 0.04 nm or less, if the root mean square value roughness (Rq) of the extracted surface shape is made into the fine swell (Rq).