Apparatus for applying bias magnetic field including a rotatable magnet and a plurality of coils for controlling the rotation of the magnet
US5351221A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 24, 1993 |
| Grant date | Sep 27, 1994 |
| Priority date | — |
| Expiry date | Aug 24, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/1056
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for applying a bias magnetic field has a magnet rotatably supported around a rotational axis parallel to a face of a magnetooptic disk and magnetized in a direction perpendicular to the rotational axis; a coil section for controlling the rotation of the magnet by flowing a driving electric current therethrough; and a first coil constituting the coil section and having a first portion parallel to the rotational axis and located on a side opposite to the magnetooptic disk with respect to the magnet, the first coil further having a second portion parallel to the rotational axis and arranged on a side of the magnet in a position near the magnetooptic disk in comparison with the rotational axis. The first coil may have a third portion for connecting both ends of the first and second portions. The coil section may have a second coil constituting the coil section and constructed such that the first and second coils are approximately arranged symmetrically with respect to a plane including the rotational axis and perpendicular to the face of the magnetooptic disk. Another bias magnetic field applying apparatus is also shown. The bias magnetic field applying apparatus may have …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.