| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance forgery preventing, falsification preventing and copy preventing functions of a valuable printed matter such as a paper money, a passport, securities, stamp or the like. SOLUTION: Illuminant 3 for emitting a light having an intrinsic wavelength region when a light having a specific wavelength region is illuminated is given to a sheet 1 having partly different opacity to constitute an optically reading sheet. Lights having a specific wavelength are illuminated to the sheet by a front side lamp 5 and a rear side lamp 9. A light emitted from the illuminant 3 is received by photosensors 6, 7 and 10, 12, voltage waveforms are simultaneously or one or more are selectively obtained, and a truth or falsehood is decided.</p> |
