Article identification process and articles for practice thereof

Details Article identification process and articles for practice thereof Article identification process and articles for practice thereof

1980-10-23

1983-06-07

Lusignan, Michael R.

Coating processes

Fraud or tamper detecting

283 92, 283901, 427 541, 427 561, 427157, 436 56, B44F 112

Patent

active

043871127

ABSTRACT:
Ordinary articles involved in transactions that require ascertaining authenticity of the article, such as wearing apparel, electronic parts, identification cards, or credit cards, may be identified as genuine through use of stimulatable inorganic phosphor compositions. The inorganic phosphors are applied to the article to be identified. The phosphors are excited to store energy therein, such as excitation by application of light as in a radiative photon process, or by application of thermal or electric fields as in a conductive process. The storage may be for however short or long a period. The result of storage is a later emission of real--time luminescence, sometimes called fluorescence, or of time-lag luminescence, sometimes called phosphorescence, or of no luminescence, where energy is either totally stored, converted to non-visible emissions such as infrared radiation, or internal conversion processed. The phosphors with stored energy as a result of this excitation are then stimulated during or after the excitation. The stimulation may be by use of light as in a radiative photon process, or by use of thermal or electric fields as in a conductive process. A change in emission of radiant energy from the phosphor as a result of the stimulation, such as change of luminescence of the phosphor, is then observed to verify the presence of the inorganic phosphor in the article. Such inorganic phosphors provide positive identification of the article because their behavior under the process steps above cannot be mimicked with organic compounds, and preparation of such inorganic phosphors, or phosphors capable of mimicking individual observed phenomena of the bona fide phosphor, especially preferred intermediate converter mixed phosphor type, is beyond the capability of counterfeiters. The behavior of such phosphors in response to the above process steps is also easily recognizable visually without use of complex analytical apparatus, thus providing an ideal forensic test.

REFERENCES:
patent: Re29334 (1977-08-01), Ryan et al.
patent: 2848348 (1958-08-01), McCafferty
patent: 3679448 (1972-07-01), Tramposch
patent: 3775173 (1973-11-01), Yamamoto et al.
patent: 4197104 (1980-04-01), Krystyniak et al.
Leverenz, Luminescence of Solids, publ. Wiley & Sons, N.Y., 1950, Table V.
Leverenz, H. W. An Introduction to Luminescence of Solids, Dover Publ., 1968, pp. 150, 151, 180-183.

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