Observation of scratch on magnetic media by, using thermal infrared camera

Decreasing of distance between head and magnetic disk, due to higher data storage density requirement, often causes scratches on the magnetic media. In order to scratch failure improvement, a practical technique for measuring or monitoring scratch on media in manufacturing is in demand. In this paper, a technique of media scratched detection by using thermal infrared camera is proposed. It is found that, in order to visibly detect a micrometer-size of scratch, the thermal infrared camera must be taken at right angle to the media and a shorter time of current biasing shows a better result on scratch detection.