Checking an identity, authority or check document or the like
First Claim
1. A checkable document, characterized in that it is provided with a marking comprising a material based upon rare earth metals, with the property that when excited by longer wave radiation it emits shorter wave radiation.
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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.
181 Citations
28 Claims
- 1. A checkable document, characterized in that it is provided with a marking comprising a material based upon rare earth metals, with the property that when excited by longer wave radiation it emits shorter wave radiation.
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8. A method of marking and checking a document, the method comprising the steps of
at the time of marking providing the document with a material based on rare earth metals, which has the property that when excited by longer wave radiation, it emits shorter wave radiation; - and
at the time of checking, irradiating at least parts of the document which are provided with said material by said longer wave radiation, and detecting the presence of consequent shorter wave radiation. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus for checking a document, which document is provided with a marking comprising a material based upon rare earth metals, having the property that when excited by longer wave radiation, it emits shorter wave radiation, the apparatus comprising means for placing the document and said radiation-generating and radiating-detecting means in a predetermined check position relatively to one another, a number of means for generating longer wave radiation for irradiation of said document;
- and a corresponding number of means for detecting shorter wave radiation emitted from said document as a consequense of said irradiation, each radiation- generating means being assigned to a specific radiation-detecting means.
- View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
Specification