| 摘要 |
<p>A composite security thread, e.g. for a bank note, is produced by coating aluminium film onto a polyester film (11) and coating selected regions with magnetic material. Photoresist characters (14 to 18) are next printed onto the magnetic material, and a chemical applied to remove the aluminium coating except where protected by the resist. An obscuring silver coating (40) is then applied over the magnetic material, and a final transparent material applied as a barrier to reduce the risk of damage during subsequent processing.</p> |
