| 摘要 |
<p>A reusable information recording material comprises a layer (10) of transparent plastics formed with dimples (16) on one side, a further plastics layer (34), having a magnetic coating (14), being bonded to the dimpled side of layer (10), with the magnetic coating (14) directly adjoining the layer (10), so that respective closed cavities are defined by the dimples (16) and the layer (34, 14). Each said cavity contains one or more indicator particles (18) in the form of permanent magnets, each indicator particle (18) being dark on the side thereof corresponding with one pole and light on the side thereof corresponding with the other pole. The indicator particles are visible from one side of the material and the arrangement is such that the orientation of each particle (18) mirrors closely the orientation of the magnetic field, due to the magnetic layer (14), in the immediate vicinity of the particle. Consequently the particles provide an accurate visual indication of the corresponding state of magnetisation of the magnetic layer (14) and therefore the particles (18) can be made to represent, in visible form, information recorded magnetically on the magnetic layer, and thus, for example can be made to display a text or graphics.</p> |
