| 摘要 |
The invention provides security devices that can be used in varying shapes and sizes for various authenticating or security applications. The security device comprises a first layer or film of an optically variable liquid crystal material 12, a second layer or film of an optically variable liquid crystal material 13 which exhibits different reflective characteristics to the first layer, and a partial layer of a light absorbing translucent material 14 between the first and second liquid crystal layers. This may form indicia such as symbols, patterns or alphanumeric characters and may be multi-coloured. Light reflected at certain angles may be in the infrared or ultraviolet regions of the electromagnetic spectrum. The device is secured to a document by adhesive layer 19. Partially demetallised polymeric film 17 carries indicia 26. |
