| abstract |
A security device comprising a substrate having an array of microlenses on one side and at least two corresponding arrays of microimages on the other side, the images being located at a distance from the microlenses substantially equal to the focal length of the microlenses, the substrate being sufficiently transparent to enable light to pass through the microlenses so as to reach the microimages, wherein the images within each array are the same, but differ from the images in the or each other array, and wherein at least one microimage array is in imperfect registration with the microlens array, the arrangement being such that when the microimages are viewed through the microlens array, moir6 .magnified versions of the images are visible and, when the substrate is tilted, the magnified images of one array move relative to the magnified images of the or each other array. WO 2005/106601 PCT/GB2005/001618 t f Figure 1 |