Optically variable security device and method

A security device comprising at least first and second superposed diffractive or holographic optically variable effect generating structures, the first structure having a surface relief microstructure and including a reflective layer formed by a high refractive index dielectric material, the second optically variable effect generating structure being a volume hologram viewable through the first optically variable effect generating structure, and wherein the replay characteristics of the structures generate a visually integrated image, an optically variable generating effect of the visually integrated image appearing to derive from one optical effect generating structure.

A method of manufacturing a security device, the method comprising providing at least first and second superposed diffractive or holographic optically variable effect generating structures, the first structure having a surface relief microstructure and including a reflective layer formed by a high refractive index dielectric material, wherein the second optically variable effect generating structure is a volume hologram viewable through the first optically variable effect generating structure, and wherein the replay characteristics of the structures generate a visually integrated image, an optically variable generating effect of the visually integrated image appearing to derive from one optical effect generating structure.

A security device comprising at least first and second superposed diffractive or holographic optically variable effect generating structures, each structure having a surface relief microstructure, the second optically variable effect generating structure being viewable through the first, wherein the first optically variable effect generating structure includes a discontinuous metallic layer, wherein a dye or pigment is provided between the optically variable effect generating structures, and wherein the replay characteristics of the structures generate a visually integrated image, an optically variable generating effect of the visually integrated image appearing to derive from one optical effect generating structure, wherein the first and second optically variable effect generating structures comprise first and second zero-order diffractive devices, wherein the first zero-order diffractive device generates an image in a first color at a first orientation and in a second color at a second orientation, while the second zero-order diffractive device generates an image in the second color in the first orientation and the first color in the second orientation.

A method of manufacturing a security device, the method comprising providing at least first and second superposed diffractive or holographic optically variable effect generating structures, each structure having a surface relief microstructure, providing the surface relief microstructure of the first optically variable effect generating structure with a discontinuous reflective metal layer;

• and providing a dye or pigment between the optically variable effect generating structures, whereby the second optically variable effect generating structure is viewable through the first, and wherein the replay characteristics of the structures generate a visually integrated image, an optically variable generating effect of the visually integrated image appearing to derive from one optical effect generating structure, wherein the first and second optically variable effect generating structures comprise first and second zero-order diffractive devices, wherein the first zero-order diffractive device generates an image in a first color at a first orientation and in a second color at a second orientation, while the second zero-order diffractive device generates an image in the second color in the first orientation and the first color in the second orientation.