| 摘要 |
A security document is disclosed having an at least semi-transparent or translucent window region of lower optical density than an adjacent non-window region of the security document. The window region is defined by at least one opacifying layer 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 disposed at least partially in the window region, comprising a first ink layer and a second ink layer 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. |
