ANTI-COUNTERFEITING LABEL FOR DETECTING CORK ALTERATIONS
A near field magnetically coupled contactless device includes a foldable substrate in the form of a tape; two metal surfaces located facing each other on opposite sides of the substrate in a region of interest of the substrate, configured such that a piercing of the region of interest causes a permanent short circuit between the two metal surfaces; and a circuit configured to detect a short circuit between the two metal surfaces.
1 . A near field magnetically coupled contactless device, comprising:
a foldable substrate in the form of a tape;
two metal surfaces located facing each other on opposite sides of the substrate in a region of interest of the substrate, configured such that a piercing of the region of interest causes a permanent short circuit between the two metal surfaces; and
a circuit configured to detect a short circuit between the two metal surfaces.
2 . The device of claim 1 , comprising:
an antenna circuit tuned to a nominal frequency, including an antenna and a first capacitor connected to the antenna; and
a sacrificial capacitor formed by the two metal surfaces connected to the antenna circuit to contribute to the tuning of the antenna circuit to the nominal frequency.
3 . The device of claim 2 , wherein the sacrificial capacitor is connected in series with the antenna.
4 . The device of claim 2 , wherein the antenna encircles the region of interest.
5 . The device of claim 2 , comprising a control microcircuit connected to be powered by the antenna circuit, and including information transmission functions and cryptographic functions; wherein the antenna circuit tuning parameters are selected so that a short circuit of the sacrificial capacitor lowers the supply power received by the microcircuit to a level insufficient for supplying the cryptographic functions, yet sufficient for supplying the transmission functions.
6 . The device of claim 2 , comprising a conductive track for connecting the sacrificial capacitor to the antenna circuit, configured to cross areas of preferential rupture of the tape.
7 . A container comprising:
a cork; and
a contactless device according to claim 6 adhesively secured over the container and the cork so that the region of interest of the substrate is in correspondence with the cork.
8 . The container of claim 7 in the form of a bottle comprising a cap enveloping the cork, the neck of the bottle, and the tape, the cap including, in the vicinity of the cork, a material permeable to magnetic field.