Patent ID: 6981648

Claim:
An information carrier medium which comprises: at least first and second sheet members each having first and second surfaces opposite to each other, said first and second sheet members being laminated together with the first surface of the first sheet member bonded to the first surface of the second sheet member; and a security indicium formed on at least one of the first surfaces of the respective first and second sheet members, said security indicium comprising a pattern of a plurality of regions with various sizes, each of the regions in said security indicium being made of a first inking material and a second inking material which are disposed separately from each other, the first inking material for giving out light in response to a first wavelength of incident light, and the second inking material for giving out light in response to a second wavelength of incident light, the light given out by the first inking material having a first wavelength different from a second wavelength, the light given out by the second inking material having the second wavelength and not having the first wavelength is different from the first wavelength, the light given out by the second inking material not having the first wavelength and having the second wavelength, the first and second sheet members being opaque to visible light and transparent to the lights of the first and second wavelengths.