Enlarged-spot erasure of optical media in dual-beam systems
US5216658A · kind A · utility
6Cited by
8References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1990 |
| Grant date | Jun 1, 1993 |
| Priority date | — |
| Expiry date | Jul 26, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0055
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for erasing data from optical media in dual beam systems. The erase spot is focused to have a diameter equal to three times the track pitch of the medium. The larger erase spot eases spot alignment requirements since even beam misalignments of half a track width still supply enough energy to the medium to erase the data bump. The larger erase spot heats a larger area more gradually than a single track width erase beam and thereby also enables a more complete erasure of the medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.