| 摘要 |
A multi-bit magnetic tag is disclosed which comprises a substrate (1) carrying a plurality of magnetised zones (2), the magnetic material from which said zones are formed being an anisotropic magnetic material having an axis of easy magnetisation; at least two of the magnetically active zones (2) are such that their easy axes of magnetisation are non-parallel. Tags of this form may be manufactured by sputtering a magnetically anisotropic material onto a substrate (1) carried on a coating drum while a non-uniform magnetic bias is applied to, or close to, the drum or the substrate (1) so as to influence the direction of the axis of easy magnetisation of the magnetically anisotropic material as it is deposited by the sputtering process. The coated substrate is then removed from the coating drum and cut into tags of the desired shape and size. Other multi-bit magnetic tags are also described. |
