Thermal sensor for in situ flying height measurements of optical flying heads

The application of flying head technology in optical recording promises a considerable increase in recording density. It may be used for both far field and near field recording. For dynamic in situ flying height and flight attitude measurements, a prototype of a thermal test head has been developed. It takes advantage of the heat transfer in sub-micrometer air bearings as well as its dependence from the air gap width. Such a test head has a slider with a similar air bearing surface as the recording head, but with thermo-resistive sensors that are energized by Joule's heat and embedded at each of the four corners. The paper describes the head design and the fabrication technology and provides first experimental test results as well.