Method for detecting surface defects in patterned media
US8169868B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 2, 2010 |
| Grant date | May 1, 2012 |
| Priority date | — |
| Expiry date | Mar 5, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/2516
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical defect detection method for patterned media includes: irradiating a laser beam onto a patterned medium and obtaining reflected light by reflection very close to a sample; outputting the reflected light as an analog electrical signal from an optical receiver; converting the analog signal to a digital signal; obtaining a surface profile in a track direction by sampling the analog signal; obtaining a servo area profile by setting a slice for detecting servo area; calculating an average value in a track width direction based on plural servo area profiles; generating a master servo area profile based on the average value; obtaining a difference between the master servo area profile and the specific servo area profile; and detecting the presence of a defect including surface roughness, process fluctuation, and adhesion of foreign matters, from a differential waveform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.