Abstract: A security device comprises a substrate (1) having an array of microlenses (3) on one side and one or more corresponding arrays of microimages (4) on the other side. The microimages (4) are located at a distance from the microlenses (3) substantially equal to the focal length of the microlenses. The substrate (1) is sufficiently transparent to enable light to pass through the microlenses (3) so as to reach the microimages (4). Each microimage (4) is defined by an anti-reflection structure on the substrate (1) formed by a periodic array of identical structural elements, light passing through the substrate and impinging on the microimages being reflected to a different extent than light which does not impinge on the microimages thereby rendering the microimages visible.

Abstract: A method of manufacturing a security device comprises: a) providing a transparent, plastics support layer releasably on a carrier layer; b) coating the plastics support layer with a radiation curable material, wherein either i) the radiation curable material inherently provides an optically variable effect or ii) the method further comprises providing the radiation curable material with an optically variable effect generating structure, c) curing the radiation curable material by exposure to suitable curing radiation; and, d) cutting through the cured material and the support layer along a boundary defining the security device.

Abstract: A security device comprises at least two regions, each region comprising a prismatic surface structure defining an array of substantially planar facets. Each region forms a reflector due to total internal reflection when viewed at least one first viewing angle and is transparent when viewed at least one second viewing angle. The said at least one first viewing angle of one region is different from the at least one first viewing angle of the other region. Furthermore, a security device comprising an asymmetrical or truncated prismatic surface structure is located in a transparent area of an article.

Abstract: The present invention relates to improvements in methods of manufacture of substrates which can be used in varying shapes and sizes for various authenticating or security applications, which combine the advantages of indicia formed from metallisation or demetallisation of a security element and the colorshift effects of liquid crystal materials. The invention therefore provides a method of manufacturing a substrate comprising the steps of applying a darkly colored resist to at least a part of a metallic layer on one side of a substantially transparent polymeric film, removing metal from areas not covered by the resist to form demetallised regions and applying a polymeric liquid crystal material over the resist and the demetallised regions.