| 摘要 |
An optical information storage disk (10) especially adapted for tamper-proof monitoring by an electronic article surveillance (EAS) system. The compact disk (10) hereof includes a generally planar, annular first disk surface (12) and an opposed, generally annular second disk surface (14), a plurality of generally concentric data tracks (24) on at least one of the disk surfaces, a centered aperture (20) and a generally annular EAS magnetic marker (16) concentrically oriented about the centered aperture. The annular EAS marker (16) comprises a dual status, multi-directional marker with a selectively demagnetizable, essentially linear magnetic switching field. The marker is preferably received within a grooved recess (18) in one of the disk surfaces and is immovably retained within the grooved recess by a coating (62) covering the disk surface. <IMAGE> |
