| 摘要 |
A security device comprises an optically variable effect generating structure (3,4). An obscuring layer (7) is located, in use, between the optically variable effect generating structure and a substrate (8) to which the device is secured. A color layer (6) is also included which exhibits one or more predetermined colors when viewed under certain viewing conditions from the side of the device remote from the obscuring layer. The obscuring layer (7) is substantially opaque under the said certain viewing conditions. |
