SUBSTRATE FOR MAGNETIC RECORDING MEDIUM, ITS SURFACE CONTROL METHOD AND MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To obtain a substrate corresponding to high recording density by setting the average height of a micro waviness to a specified value so that modulation becomes a desired value from a correlation between the average height of the micro waviness and the modulation. SOLUTION: In a substrate for a magnetic recording medium, the average height (average value) Ra' of a micro waviness obtained by measuring the main surface with a non-contact laser interfering method is compared with the result obtained by evaluating the modulation of the magnetic recording medium, and the average height (average value) Ra' of the micro waviness such that the modulation becomes a desired value from both correlations is set to be obtained. Where the average height Ra' of the micro waviness is the value obtained by a formula. Hereupon, xi expresses the measuring point value in the measuring point (the height from a reference line to a measuring curve in the measuring point), X expresses the average value of the measuring point values and (n) expresses the member of the measuring point.