Near field optical certifying head for disc asperity mapping
US6445447B1 · kind B1 · utility
4Cited by
46References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 24, 1998 |
| Grant date | Sep 3, 2002 |
| Priority date | — |
| Expiry date | Mar 24, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/268
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical certifying head flies above a disc surface within an evanescent decay length of the disc surface. A light beam is focused through an objective lens, and further focused through a SIL. The SIL-focused light is coupled to the disc surface through near-field coupling. The light is reflected from the disc surface depending on a surface condition of the disc such that the surface condition can be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.