Patent ID: 6132651
Filing Date: 2000-10-17
Classification: G11B,Y10S

Abstract:
An improvement in a process for producing a magnetic recording medium comprising a step of focusing a laser beam for texturing a surface of a substrate disc to form a multiplicity of microscopic bumps on the disc surface, said improvement comprising focusing the laser beam in a manner such that spacings D between adjacent microscopic bumps in the circumferential direction of the substrate disc are varied to an extent such that the following formula (1) is satisfied:1.ltoreq.[(D.sub.max -D.sub.min)/D.sub.avg ].times.100(%).ltoreq.200(1)wherein D.sub.max, D.sub.min and D.sub.avg are the maximum spacing, minimum spacing and average spacing, respectively, among the spacings D between adjacent microscopic bumps in the circumferential direction of the substrate disc, as determined by a method wherein 2.5% of the total number of spacings D, having the largest dimensions, and 2.5% of the total number of spacings D, having the smallest dimensions, are excluded, and D.sub.max, D.sub.min and D.sub.avg are measured on the remaining 95% of the total number of spacings D.