Valuable document, e.g. a banknote, incorporates a resonant conducting structure with leads running along the edge of the note, such that when one of the leads is broken the frequency changes

摘要

Valuable document, e.g. banknote or passport, has a planar electrically insulating substrate with an enclosing edge (18). The substrate is provided with a planar, electrically conducting structure (12) with conducting leads (16) that form a resonant circuit. The conducting leads run in sections (20b, 22b, 22c) along the edges of the substrate. Lead sections are arranged along the edges so that a circuit break changes the resonant frequency of the circuit. An independent claim is included for a method for checking the condition of valuable documents.