| 摘要 |
A security document 1 has an at least semi-transparent or translucent window region 2 of lower optical density than an adjacent non-window region 3 of the security document. The window region is defined by at least one opacifying layer 6a, 6b of the security document which is present in the non-window region and not in the window region of the document. The security document further includes an optically variable security device 10 disposed at least partially in the window region, comprising a first ink layer 11 and a second ink layer 12 which at least partially overlap one another in the window region, wherein the first ink layer comprises a non-iridescent, semi-transparent ink composition with a visible colour which does not vary with viewing angle, and the first ink layer has a different composition from the at least one opacifying layer of the security document. The second ink layer comprises an iridescent, semi-transparent ink composition, the appearance of which varies according to the viewing angle. |
