| 摘要 |
A security document (1) including a substrate (3) of transparent polymeric material, and opacifying layers (5, 6) provided on opposing sides of the substrate (3). The opacifying layers (5, 6) act to guide light propagating within the substrate (3). The opacifying layers (5, 6) only partially cover the substrate (3) to form one or more windows (9). The substrate (3) is formed with at least one micro-prism (13) for diverting light propagating within the substrate (3) out of the windows (9) to thereby provide a contrast enhancement between specific areas of the security document (1) and remaining areas. The micro-prisms (13) may also be arranged to direct light incident on the windows (9) to propagate along the substrate (3) and out of an (edge 19), (21) of the substrate (3). The light emission caused by the micro-prisms (13) may be used to determine a characteristic of the security document (1). |
