Detection apparatus and method
First Claim
1. A detector for authenticating an article provided with a taggant security mark, comprising:
- a radiation source for irradiating the taggant with a pulse of excitation radiation so as to cause the taggant to emit luminescent radiation that decays with time, wherein in use the taggant is repeatedly irradiated;
a radiation detector for detecting the luminescent radiation emitted from the taggant;
a storage means for storing a reference reading and a decay reading of the luminescent radiation emitted from the taggant after each pulse of excitation radiation;
a controller for ratioing the reference reading and the decay reading to generate decay ratio data;
a radiation source adjustment means for adjusting the intensity of the excitation radiation emitted by the radiation source depending on previously measured ratio data; and
authentication means for authenticating the article by referencing the ratio data generated.
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Accused Products
Abstract
Apparatus for detection of infrared radiation emitted from a taggant following excitation of the taggant sample measures the decay time of the radiation used. If the decay characteristic is accurately measured, the particular taggant can be accurately identified. The apparatus comprises an electronic controller, light-emitting diodes, a photo-detector, a first amplifier, a three-way sampling switch, filter/stores, second amplifiers and an output display. The infrared emission is excited by repeatedly illuminating the taggant for a period of microseconds every few milliseconds. When the light source is turned off, the sample continues radiating for a few milliseconds. The emission is detected by photo-detector sensitive to the 800 to 1000 nm waveband thereby rejecting interference from visible light sources.
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Citations
18 Claims
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1. A detector for authenticating an article provided with a taggant security mark, comprising:
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a radiation source for irradiating the taggant with a pulse of excitation radiation so as to cause the taggant to emit luminescent radiation that decays with time, wherein in use the taggant is repeatedly irradiated; a radiation detector for detecting the luminescent radiation emitted from the taggant; a storage means for storing a reference reading and a decay reading of the luminescent radiation emitted from the taggant after each pulse of excitation radiation; a controller for ratioing the reference reading and the decay reading to generate decay ratio data; a radiation source adjustment means for adjusting the intensity of the excitation radiation emitted by the radiation source depending on previously measured ratio data; and authentication means for authenticating the article by referencing the ratio data generated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of authenticating an article provided with a taggant security mark, comprising:
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repeatedly irradiating the taggant with a pulse of excitation radiation so as to cause the taggant to emit luminescent radiation that decays with time; detecting the luminescent radiation emitted from the taggant; storing a reference reading and a decay reading of the luminescent radiation emitted from the taggant after each pulse of excitation radiation; ratioing the reference reading and the decay reading to generate decay ratio data; adjusting the intensity of the excitation radiation emitted by the radiation source depending on previously measured ratio data; and authenticating the article by referencing the ratio data generated. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification