| 摘要 |
<p>PURPOSE: To test the authenticity of a security document by passing the security document through an inspection device at a certain speed and under the condition in which a security thread becomes vertical to the transport direction, by detecting the physical properties of individual areas and their changes with the passage of time and by determining the geometrical distribution of various areas of the security thread based on the testing signals coming from these areas. CONSTITUTION: Inside a security document 37, a security thread 4 is embedded, which can be confirmed visually by either reflected light or transmitted light and which has particular physical properties detectable mechanically. The said security document 37 is passed through an inspection device 42 at a certain speed and under the condition in which the security thread 4 becomes vertical to the transport direction. When the security document 37 passes through the inspection device 42, physical properties and their changes with the passage of time in individual areas of the security thread 4 are detected by using one or more sensors. Then, based on the testing signals coming from various areas of the security thread 4, the geometrical distribution of these areas are determined and compared with the prescribed values. As a result, a security thread hardly reproducible for a counterfeiter can be inspected promptly.</p> |
