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Primary Examiner: Dixon, Harold A.
Assistant Examiner:
Attorney: Burns, Doane, Swecker & Mathis

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Title: Checking an identity, authority or check document or the like

Abstract: A document such as an ID-card is provided with check markings comprising a material based upon rare earth metals and having the property that when excited by IR radiation it emits visible light. When checking the document, the document is irradiated with pulsed IR radiation, the occurrence of corresponding visible light pulses originating from said material being detected. The visible light pulses have well defined rise and decay times dictated by the check material used, which fact is used to check that output pulses from the detector are the correct ones for indicating the genuiness of the document.

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Other info:

Inventors: Malmberg, Thor Anders Helge (Stockholm, SW)
Hogberg, Knut Goran (Hasselby, SW)
Sjoquist, Stig Roland (Vallentuna, SW)

Application Number: 624473
Filing Date: 1975-10-21
Publication_date: 1977-09-06
Assignee: AB ID-Kort (Stockholm, SW)
Primary Class(es): 250/341.1 250/330, 250/338.1, 250/458.1
Other Classes:
US Patent Ref:

3070698	Dec, 1962	Bloembergen	250/459.
3105908	Apr, 1965	Burkhardt et al.	250/461.
3452332	Jun, 1969	Bron et al.	250/271.
3473027	Oct, 1969	Freeman et al.	250/365.
3539941	Nov, 1970	Halverson	250/461.
3564215	Feb, 1971	Peoples	250/271.
3586640	Jun, 1971	Pershan	250/330.
3654463	Apr, 1972	Geusic	250/486.
3663813	May, 1972	Shaw	250/365.
3764807	Oct, 1973	Pollack	250/330.
3793527	Feb, 1974	Forest	250/461.
3958970	May, 1976	Auzel et al.	250/487.

Other Refs: Other References: Efficient Green-Emitting IR Phosphors by Kano et al., Electro Chemical Society vol. 119 No. 11 Nov. 1972 pp. 1561-1564.