Patent ID: 7839546

Claim:
A security device comprising: a surface relief microstructure which, in response to incident radiation, replays a hologram viewable within a viewing zone, the hologram comprising: at least a first holographic image element in an image plane spaced from the surface of the microstructure, the device exhibiting at least one further image in a plane spaced from said image plane of the first holographic image element, wherein the spacing between the first holographic image element image plane and the plane of the at least one further image is such that, on tilting the device through a maximum viewing angle of 45°, the first holographic image element exhibits an apparent rate of movement relative to the at least one further image, the rate of movement being at least 6 mm per radian of tilt, and the product of the rate of movement and an included angle of the viewing zone defining a distance at least 18% of a dimension of the device in the parallax direction.