| 摘要 |
A security element, a security device and a method of forming a security device is disclosed, the security element including a plurality of focusing elements, a first group of image elements, and a second group of image elements, each image element being located in an object plane to be viewable through a focusing element, and being located a distance from the focusing element such that the focal point width of the focusing element in the object plane is substantially equal to the size of the image element or differs from the size of the image element by a predetermined amount, wherein image elements of the first group are visible in a first range of viewing angles and image elements of the second group are visible in a second range of viewing angles, and wherein a second image formed in the second range of viewing angles is a contrast-inverted version of a first image formed in the first range of viewing angles. The security element is particularly suitable for use on security documents, such as banknotes. |
