Importance

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Abstract

An apparently conventional document such as an identification (ID) card is constructed as a laminate within which is a code or other coding indicia such as a photograph, bar code or fingerprint. concealed from human view. The document is read by a conventional electro-optic reader means placed against a face of the card, if the reader uses a beam of light in the wavelength absorbed by the material with which the coded indicia is produced, but reflected by the background against which the coded indicia is 'seen' by the beam. The card is preferably a laminate of at least an upper lamina and a lower lamina, each made of a synthetic resin which has a substantially white imprintable surface conventionally printed with the identification of the owner of the card with a pigment-free, non-aqueous ink which is visible to the human eye but substantially transparent to wavelengths outside the visible range. Typically, both the upper and lower laminae, are opaque to visible light, but the face through which the coded indicia is to be read by the reader, is transparent to the reader's beam. The code is read because there is sufficient contrast between the transmitted and absorbed light in the wavelength used by the reader.

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First Claim