HERMETICALLY SEALED BIAS MAGNET ASSEMBLY FOR MAGNETO-OPTIC DISC DRIVE

摘要

A hermetically sealed bias magnet assembly (30) for use in a magneto-optic drive system for recording data onto a magneto-optic disc (16) utilizes a permanent magnet (34) that is rotatably mounted in a hermetically sealed chamber (52) of a housing that has a second chamber (58) containing a drive coil (32) that rotates the magnet to thereby change the polarity of the magnet field applied to the disc. Hermetic sealing of the magnet permits a small magnet and small bearings to be used to provide the low rotational mass required for rapid operation and avoids the performance degradation that often occurs when small components are exposed to a hostile environment.