The study of scratch detection on magnetic disks by using a thermal infrared camera

Abstract

Presently, hard disks require a greater recording density as their sizes are increasing. This results in a lessened distance between the inscriber/reader heads and the disks, which in turn may cause contact between the disk surface and the head, and hence unwanted scratches. This study attempted to detect scratches on magnetic disks by using a thermal infrared camera. When direct and alternate currents are applied on the disk surface, the thermographs are similar, i.e., no scratches have been detected since they are too small.The different emissivity between the scratched and normal surfaces is similar. However,an alternative detection method can be improved by a different emissive surface technique, which results in a clearer detection of scratches.