| 摘要 |
The filament or film has a supple backing layer (3), an opaque layer (4) marked with identification letters, numerals or other characters by YAG laser beam engraving, and an optional transparent layer (5). The engraving tolerances are of the order of plus or minus ten per cent for engraving with a width of under 100 microns and plus or minus five per cent for an engraving width of over 100 microns. A variant of the design can have a series of opaque layers, of which one or all are engraved, alternating with transparent layers. The opaque layers are made from a metal or based on a metal oxide, especially of aluminum, a magnetic material, or different coloured inks. The transparent layer is of varnish, a magnetic coating, or transparent coloured, fluorescent, thermochrome or iridescent inks. |
