US4376264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of checking the authenticity of papers and physically identifiable paper for use in said method
Assignee: Papierfabrieken Van Houtum & Palm
•
Filing: 1981-02-04
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Granted: 1983-03-08
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Expires: 2001-02-04
Abstract
Abstract A method of checking the authenticity of papers, such as banknotes, 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 D. Dokter
- 👤 Roelof Hildering
- 👤 Adrianus Mackor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:42
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 which comprises 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 which comprises 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
20 words
Paper according to claim 3, wherein the doped material on burning of the paper constitutes a component of the ash.
Claim 7
Dependent Claim
15 words
Paper according to claim 3, wherein the oxide or salt has been doped with manganese.
Claim 8
Dependent Claim
15 words
Paper according to claim 3, wherein the oxide or salt has been doped with gadolinum.
Claim 9
Dependent Claim
13 words
Paper according to claim 3, wherein the host crystal has a perovskite structure.
Claim 10
Dependent Claim
20 words
Paper according to claim 3, wherein the host crystal is chosen from the group consisting of magnesia, calcia and strontia.
Claim 11
Dependent Claim
11 words
Paper according to claim 3, wherein the paper is a banknote.
References Cited (Backward Citations)
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US3348136A
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US3358222A
Cited
US3480785A
Cited
US3491243A
Cited
US4267620A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-07 | 1986-09-06 | 1987-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-07 | 1990-09-06 | 1991-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-07 | 1994-09-06 | 1995-03-08 | $7700.00 | Window Closed / Lapsed |