| 摘要 |
The present invention relates to a security structure (10) comprising at least: a first set (O1) of microperforations all forming a single first angle (a1) to the normal to the structure, and defining a first pattern visible when observed in a direction of observation that coincides with the axis of the microperforations of the first set; and a second set (O2) of microperforations all forming a single second angle (a2) to the normal to the structure, which is different from the first angle, said second set defining a second pattern visible when observed in a direction of observation that coincides with the axis of the microperforations of the second set. |
