EP0033994A1
Expired / Lapsed
EP
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A method of checking the authenticity of papers
Assignee: Papierfabrieken Van Houtum & Palm Bv
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Filing: 1981-02-04
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Granted: —
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Expires: 2001-02-04
Abstract
Abstract A method of checking the authenticity of papers, such as ba nknotes, is provided which comprises using authentic paper containing a minor amount of substance showing an ESR spectrum at room temperature and checking the authenticity by ESR spectroscopy, as well as paper for use in said method, containing a minor amount of a compound showing an ESR spectrum at room temperature, said compound being either an oxide or salt having a crystal lattice of cubic symmetry doped with such a metal, or an oxide or salt of arbitrary symmetry doped with a freely rotatable ion containing such a metal.
Inventors
- 👤 Hendrik Daniel Dokter
- 👤 Roelof Hildering
- 👤 Adrianus Mackor
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 23:34
CPC Classifications
D; D21; D21H; D21H21/00; D21H21/14; D21H21/40; D21H21/44; D21H21/48; G; G01; G01N; G01N24/00; G01N24/10; G07; G07D; G07D7/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
42 words
A method of checking the authenticity of papers in a physical way, characterized by using authentic paper containing a minor amount of a substance showing an electron spin resonance spectrum at room temperature, and checking the authenticity by electron spin resonance spectroscopy.
Claim 2
Independent Claim
42 words
A method of checking the authenticity of papers in a physical way, characterized by using authentic paper containing a minor amount of a substance showing an electron spin resonance spectrum at room temperature, and checking the authenticity by electron spin resonance spectroscopy.
Claim 3
Dependent Claim
12 words
A method according to claim 1, wherein said paper is a banknote.
Claim 4
Dependent Claim
87 words
Physically identifiable paper for use in the method of claim 1 containing a minor amount of a compound of a metal which has an incompletely filled 3d or 4f orbital, characterized by the fact that said compound shows an electron spin resonance spectrum at room temperature and is either an oxide or salt having a crystal lattice of cubic symmetry doped with such a metal, or an oxide or salt of arbitrary symmetry of the crystal lattice doped with a freely rotatable ion containing such a metal.
Claim 5
Dependent Claim
24 words
Paper according to claim 3, wherein the doped salt or oxide has been incorporated in a fiber which has been woven in the paper.
Claim 6
Dependent Claim
22 words
Paper according to claim 3 or 4, wherein the doped material on burning of the paper constitutes a component of the ash.
Claim 7
Dependent Claim
19 words
Paper according to any of claims 3 - 5, wherein the oxide or salt has been doped with manganese.
Claim 8
Dependent Claim
19 words
Paper according to any of claims 3 - 5, wherein the oxide or salt has been doped with gadolinum.
Claim 9
Dependent Claim
17 words
Paper according to any of claims 3 - 7, wherein the host crystal has a perovskite structure.
Claim 10
Dependent Claim
24 words
Paper according to any of claims 3 - 7, wherein the host crystal is chosen from the group consisting of magnesia, calcia and strontia.
Claim 11
Dependent Claim
13 words
Paper according to claims 3 - 9, wherein the paper is a banknote.
References Cited (Backward Citations)
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