Write and erase magnetic bias field switching system for a magneto-optic disk drive
US4977549A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 20, 1988 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Sep 20, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10554
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optic disk drive includes a magneto-optic disk and a rotary arm for positioning a focus/bias field switching assembly adjacent bit positions on the disk. A bias field switching assembly includes an annular permanent magnet mounted within a guide for movement between write and erase positions and an objective lens. The magnet has central and pole surfaces generally parallel to the disk. Coils on the guide are energized to drive the magnet between the write and erase positions. In its erase position the magnet impinges a first polarity erase magnetic field on the disk. In its write position the magnet impinges a second polarity write magnetic field upon the disk. The magnet is releasably latched in both its write and erase positions by ferro-magnetic elements mounted to the guide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.