Patent ID: 10723164

Abstract:
A method of manufacturing a security device is provided. The method comprises providing a substrate, the substrate having opposing first and second surfaces and a relief structure formed in the first surface of the substrate. A reflection enhancing layer is applied over the first surface of the substrate such that the reflection enhancing layer at least partially overlaps the relief structure and such that a first region of the first surface of the substrate does not have the reflection enhancing layer. An absorber layer is applied over the reflection enhancing layer such that the absorber layer at least partially overlaps the reflection enhancing layer and the relief structure where the reflection enhancing layer and the relief structure overlap each other, and such that the absorber layer at least partially overlaps the first region of the first surface of the substrate. An optical spacer layer is applied over the absorber layer such that the optical spacer layer at least partially overlaps the absorber layer, reflection enhancing layer and the relief structure where the absorber layer, reflection enhancing layer and the relief structure overlap each other, and such that the optical spacer layer at least partially overlaps the absorber layer and the first region where the absorber layer and the first region overlap each other. A reflector layer, formed of an at least partially reflective material, is applied over the optical spacer layer such that the reflector layer at least partially overlaps the optical spacer layer, the absorber layer, the reflection enhancing layer and the relief structure where the optical spacer layer, the absorber layer, the reflection enhancing layer and the relief structure overlap each other, and such that the reflector layer at least partially overlaps the optical spacer layer, the absorber layer and the first region where the optical spacer layer, the absorber layer and the first region overlap each other. The reflection enhancing layer and the absorber layer are formed of the same material. The absorber layer, the optical spacer layer and the reflector layer, together, form a colour-shifting structure. The reflection enhancing layer and the absorber layer, together, are substantially opaque or transmit less than 40% of incident light, preferably less than 20% of incident light.