CHARACTERIZATION OF MAGNETIZING PROCESS FOR PRE-EMBOSSED SERVO PATTERN OF PLASTIC HARD DISKS

Rigid disks which have pre-embossed servo patterns have been developed . These media make it possible to follow tracks less than 5 mu m pitch . The substrates are made hom plastic; and pre-embossed servo patterns and discrete data tracks are made by a stamping technology similar to optical disks. To generate signals from pre-embossed servo patterns, the magnetization direction of the elevated pattern and recessed area must be opposing. Therefore, a two-step magnetization method has been developed. Based on experimental results, optimum conditions are met w hen the magnetization transition occurs at the upper edge of the patte rns.