Detection of defects embedded in servo pattern on stamper by using scattered light
US6903888B2 · kind B2 · utility
4Cited by
3References
18Claims
0Family size
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Key dates
| Filing date | Jan 15, 2003 |
| Grant date | Jun 7, 2005 |
| Priority date | — |
| Expiry date | Jun 27, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Defects of a hard disk drive servo pattern stamper are detected by comparing a scattered light beam pattern against the known servo pattern. A magnetic field is applied to stamper and the beam is linearly polarized. Variations in the physical offset of the beam, its scatter, are indicative of physical defects. Variations in the Kerr rotation of scattered beam are indicative of magnetic defects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.