| 摘要 |
An optically variable device, including a plurality of groups of surface relief elements. The groups are interlaced and/or stacked. A first group of relief elements is characterised by a first height or depth and produces a first type of optical and/or electromagnetic effect. A second group of relief elements is characterised by a second height or depth which is different to the first height or depth. The second group produces a second different type of optical and/or electromagnetic effect than that produced by the first group. |
