摘要 |
<p>The element (1) has a half-tone image type and/or standard rainbow holography type optical structure (2) e.g. optically variable diffractive structure, representing a pattern (22). An achromatic optical structure (3) represents another pattern (23) partially identical to the former pattern. Half-tone image (26) of the former structure has a set of points obtained by perforation, deposition and/or removal of materials. The materials are chosen from metals such as copper, tin, chromium, silver, gold and nickel, metallic compounds, alloys e.g. stainless steel, varnishes or metallic inks. An independent claim is also included for a security support made of natural fibrous materials such as cellulose and/or cotton, and/or synthetic fibers.</p> |