Magnetic recording media and servo systems using light-transmitting optical gratings
US4816939A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 1986 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Aug 21, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/82
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Magnetic recording media, and magnetic recording systems using such media, are disclosed which incorporate a light-transmitting optical grating at least substantially coextensive with the magnetic recording area. A second light-transmitting optical grating is associated with the magnetic transducer or read/write head. A moire pattern is produced by light transmitted through both optical gratings, and changes in the moire pattern resulting from changes in the alignment of the optical gratings resulting from movement of the read/write head relative to the media are utilized to provide servo information to keep the magnetic transducer aligned with the magnetic track. Higher magnetic recording capacities may be obtained using such media and systems, since none of the magnetic recording area is used for servo information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.