Method for detecting surface defects in patterned media

A method for processing patterned media comprising a first process for producing a patterned medium having a predetermined magnetic pattern, and a second process for detecting defects on a surface of the patterned medium produced by the first process,

• wherein the second process includes the steps of:
• irradiating a laser beam onto the surface of the rotating patterned medium;
• detecting reflected light from the surface of the patterned medium by an optical receiver, and converting the detected light to an analog electrical signal;
• converging the analog electrical signal to a digital signal by an analog/digital converter;
• distinguishing between a data area and a servo area based on a profile obtained by sampling the digital signal;
• obtaining a differential waveform by taking a difference between the profile of the distinguished data servo area and a master servo area profile prepared in advance;
• and
• determining the presence or absence of a defect based on a predetermined threshold with respect to the obtained differential waveform.