| 摘要 |
A security paper comprising a first layer of paper having an inner surface and an outer surface, a second layer of paper having an inner surface and an outer surface, and an authentication indicator disposed on an inner surface of at least one of said layers of paper; the inner surfaces of said layers of paper being affixed relative to each other to form a lamination with said authentication indicator being disposed therebetween and said authentication indicator being substantially imperceptible in said security paper in reflected light of visible wavelength. In a preferred embodiment, the security paper includes two layers of paper each having predetermined mechanical properties, color and optical density. Authentication indicia are printed on the inner surface of at least one layer. The indicia are formed of a chemically, mechanically and thermally stable medium. A chemically, mechanically and thermally stable adhesive permanently adheres the inner surfaces of the layers together. The color and optical density of the layers, the color, color intensity and optical density of the medium and the color and optical density of the adhesive are chosen to render the authentication indicia substantially imperceptible in reflected light but detectable in transmitted light. <IMAGE> |
