| 摘要 |
<p>Security document (1) with security indicia (21) for preventing unauthorised reproduction, the security indicia being detectable in transmitted light, wherein the security indicia are located within the bounds of a security pattern (20) acting to visually conceal the security pattern in reflected light. The security pattern may be formed of one or more elements (25) and may have a complexity selected to enable the concealment of the security indicia (21).</p> |
