Identification tag
First Claim
1. An identification tag, comprising:
- a) transponding means for receiving interrogating radiation and for emitting modulated radiation in response; and
b) modulating means for modulating the received interrogating radiation in a manner indicative of tag identity to generate the modulated radiation, the transponding means including first and second structures for receiving first and second radiation components of the interrogating radiation and generating corresponding first and second signals respectively, said first and second components being at mutually different frequencies, the modulating means including a coupling structure operative for receiving the second signal and generating corresponding acoustic radiation, and for coupling the acoustic radiation to the first structure, the acoustic radiation modulating the first signal in the first structure to generate the modulated radiation, the coupling structure comprising a piezo-electric film for generating the acoustic radiation in response to the second signal, the first and second structures comprising radio antennas for receiving the interrogating radiation and emitting the modulated radiation, and the antennas comprising conductive regions formed onto the piezo-electric film on a surface of the tag, the film being operative to generate the acoustic radiation in response to the second signal.
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Accused Products
Abstract
An identification tag is provided comprising a multilayer assembly incorporating, in sequence, a metal backing layer, a bulk structural layer, a piezo-electric layer and an electrode layer. The electrode layer incorporates antennas structures for receiving interrogating radiation comprising a first radiation component at a relatively lower frequency and a second radiation component at a relatively higher frequency. The electrode layer also incorporates a structure for modulating a second signal generated in response to receiving the second component by a first signal generated in response to receiving the first component to generate a modulated signal which is re-emitted as reflected radiation from the tag. The presence of the tag is determinable from modulation components present in the reflected radiation, thereby distinguishing the tag from other objects capable of reflecting radiation, but not modulating it.
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Citations
22 Claims
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1. An identification tag, comprising:
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a) transponding means for receiving interrogating radiation and for emitting modulated radiation in response; and
b) modulating means for modulating the received interrogating radiation in a manner indicative of tag identity to generate the modulated radiation, the transponding means including first and second structures for receiving first and second radiation components of the interrogating radiation and generating corresponding first and second signals respectively, said first and second components being at mutually different frequencies, the modulating means including a coupling structure operative for receiving the second signal and generating corresponding acoustic radiation, and for coupling the acoustic radiation to the first structure, the acoustic radiation modulating the first signal in the first structure to generate the modulated radiation, the coupling structure comprising a piezo-electric film for generating the acoustic radiation in response to the second signal, the first and second structures comprising radio antennas for receiving the interrogating radiation and emitting the modulated radiation, and the antennas comprising conductive regions formed onto the piezo-electric film on a surface of the tag, the film being operative to generate the acoustic radiation in response to the second signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A personnel wearable identity card incorporating an identification tag, comprising:
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a) transponding means for receiving interrogating radiation and for emitting modulated radiation in response; and
b) modulating means for modulating the received interrogating radiation in a manner indicative of tag identity to generate the modulated radiation, the transponding means including first and second structures for receiving first and second radiation components of the interrogating radiation and generating corresponding first and second signals respectively, said first and second components being at mutually different frequencies, the modulating means including a coupling structure operative for receiving the second signal and generating corresponding acoustic radiation, and for coupling the acoustic radiation to the first structure, the acoustic radiation modulating the first signal in the first structure to generate the modulated radiation, the coupling structure comprising a piezo-electric film for generating the acoustic radiation in response to the second signal, the first and second structures comprising radio antennas for receiving the interrogating radiation and emitting the modulated radiation, and the antennas comprising conductive regions formed onto the piezo-electric film on a surface of the tag, the film being operative to generate the acoustic radiation in response to the second signal.
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20. An anti-theft tag for counteracting theft of items attached thereto, the anti-theft tag incorporating an identification tag, comprising:
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a) transponding means for receiving interrogating radiation and for emitting modulated radiation in response; and
b) modulating means for modulating the received interrogating radiation in a manner indicative of tag identity to generate the modulated radiation, the transponding means including first and second structures for receiving first and second radiation components of the interrogating radiation and generating corresponding first and second signals respectively, said first and second components being at mutually different frequencies, the modulating means including a coupling structure operative for receiving the second signal and generating corresponding acoustic radiation, and for coupling the acoustic radiation to the first structure, the acoustic radiation modulating the first signal in the first structure to generate the modulated radiation, the coupling structure comprising a piezo-electric film for generating the acoustic radiation in response to the second signal, the first and second structures comprising radio antennas for receiving the interrogating radiation and emitting the modulated radiation, and the antennas comprising conductive regions formed onto the piezo-electric film on a surface of the tag, the film being operative to generate the acoustic radiation in response to the second signal.
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21. A combination comprising:
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a) an identification tag including i) transponding means for receiving interrogating radiation and for emitting modulated radiation in response; and
ii) modulating means for modulating the received interrogating radiation in a manner indicative of tag identity to generate the modulated radiation, the transponding means including first and second structures for receiving first and second radiation components of the interrogating radiation and generating corresponding first and second signals respectively, said first and second components being at mutually different frequencies, the modulating means including a coupling structure operative for receiving the second signal and generating corresponding acoustic radiation, and for coupling the acoustic radiation to the first structure, the acoustic radiation modulating the first signal in the first structure to generate the modulated radiation, the coupling structure comprising a piezo-electric film for generating the acoustic radiation in response to the second signal, the first and second structures comprising radio antennas for receiving the interrogating radiation and emitting the modulated radiation, and the antennas comprising conductive regions formed onto the piezo-electric film on a surface of the tag, the film being operative to generate the acoustic radiation in response to the second signal; and
b) an apparatus for interrogating the tag, the apparatus operative to emit the interrogating radiation to the tag, said interrogating radiation comprising first and second radiation components, and operative to receive modulated radiation emitted from the tag in response to the interrogating radiation and to determine identity of the tag from radiation components present in the modulated radiation corresponding to the first radiation component modulated by the second radiation component.
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22. A strain sensor incorporating an identification tag, comprising:
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a) transponding means for receiving interrogating radiation and for emitting modulated radiation in response; and
b) modulating means for modulating the received interrogating radiation in a manner indicative of tag identity to generate the modulated radiation, the transponding means including first and second structures for receiving first and second radiation components of the interrogating radiation and generating corresponding first and second signals respectively, said first and second components being at mutually different frequencies, the modulating means including a coupling structure operative for receiving the second signal and generating corresponding acoustic radiation, and for coupling the acoustic radiation to the first structure, the acoustic radiation modulating the first signal in the first structure to generate the modulated radiation, the coupling structure comprising a piezo-electric film for generating the acoustic radiation in response to the second signal, the first and second structures comprising radio antennas for receiving the interrogating radiation and emitting the modulated radiation, and the antennas comprising conductive regions formed onto the piezo-electric film on a surface of the tag, the film being operative to generate the acoustic radiation in response to the second signal, wherein the first structure comprises a launcher electrode connected to the second structure, an interdigitated surface acoustic wave structure and a dipole antenna connected to the interdigitated structure, the launcher electrode being operative to couple the second signal to generate surface acoustic waves, the interdigitated structure operative to receive the waves which modulate its electrical characteristics, and the dipole antenna being operative to receive the first component and to generate the first signal which the interdigitated structure is arranged to modulate to provide the modulated radiation, and wherein the sensor is operative to sense strain coupled to the tag causing change in the interdigitated structure and inducing corresponding changes induced in the modulated radiation.
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Specification