Rabin & Berdo, P.C.
Patterned medium inspection method and inspection device
A defect inspection method and device for a perpendicular magnetic recording medium that has discrete recording tracks and grooves between recording tracks, including DC demagnetizing the perpendicular magnetic recording medium, detecting a reproduced signal from the perpendicular magnetic recording medium after the DC demagnetizing, removing output fluctuation components caused by the grooves from the reproduced signal using a filter with a prescribed cutoff frequency and separating a peak output of the reproduced signal, comparing the peak output with a prescribed reference signal, and identifying a location where the peak output exceeds the reference signal as a defect location. The method further includes performing an envelope-detection on the reproduced signal, detecting a pre-format region in the perpendicular magnetic recording medium using the envelope-detection result, masking the detected pre-format region, and detecting the defect location in a region outside the masked pre-format region in the perpendicular magnetic recording medium.
Fuji Electric Device Technology Co., Ltd
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Hiroto
Kikuchi