| 摘要 |
PROBLEM TO BE SOLVED: To provide a personal identification card, simple and high in security. SOLUTION: Luminous invisible ink, reacting to light having a specified wavelength, is injected by an ink jet system to print a fingerprint on the surface of the card. In another method, transparent ink, having impermeability against light having the wavelength of a specified frequency, is injected to print the fingerprint on the surface of a transparent card. |
