US4446204A
Expired / Lapsed
US
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Security paper with authenticity features
Assignee: GAO GESELLSCHAFT fur AUTOATION und ORGANISATION MBH
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Filing: 1981-05-29
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Granted: 1984-05-01
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Expires: 2001-05-29
Abstract
Abstract Security paper with authenticity characteristics embodied therein or printed thereon which are both ferrimagnetic and also only slightly absorbed in the infrared spectral region. The presence of both properties at the same position on the security paper is tested, wherein both tests can preferably be carried out simultaneously. Materials which show this rare combination of properties are some ferrites, ferrimagnetic garnet compounds and the so-called green ferromagnetic compounds.
Inventors
- 👤 Wittich Kaule
- 👤 Gerhard Schwenk
- 👤 Gerhard Stenzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:57
CPC Classifications
D; D21; D21H; D21H21/00; D21H21/14; D21H21/40; D21H21/44; D21H21/48; B; B41; B41M; B41M3/00; B41M3/14; B41M3/144; G; G06; G06K; G06K19/00; G06K19/06; G06K19/08; G06K19/10; G06K19/14; G07; G07D; G07D7/00; G07D7/04; G07D7/06; G07D7/12; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/913; Y10S428/916; Y10S428/917; Y10S428/918; Y10T; Y10T428/00; Y10T428/25; Y10T428/26; Y10T428/261; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/31504; Y10T428/31551; Y10T428/31634; Y10T428/31678; Y10T428/31703
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
69 words
A security document with authenticity features, comprising: a carrier material having a known infra-red absorption characteristic; and a coloring agent having magnetic properties for enabling magnetic verification of said security document to be conducted, said coloring agent having an infra-red absorption characteristic such that in at least one given spectral region said coloring agent absorbs infra-red radiation less than or substantially to the same extent as said carrier material.
Claim 2
Dependent Claim
69 words
A security document with authenticity features, comprising: a carrier material having a known infra-red absorption characteristic; and a coloring agent having magnetic properties for enabling magnetic verification of said security document to be conducted, said coloring agent having an infra-red absorption characteristic such that in at least one given spectral region said coloring agent absorbs infra-red radiation less than or substantially to the same extent as said carrier material.
Claim 3
Dependent Claim
26 words
A security document according to claim 1 wherein the transmission curve for infra-red radiation at the shortwave boundary of said spectral region changes with characteristic structure.
Claim 4
Dependent Claim
66 words
A security document according to claim 1 wherein said coloring agent comprises a ferrimagnetic garnet compound of the general formula M 3-2x M' 2x Fe 5-x V x O 12 wherein x has a value between 0 and 1.2, wherein M denotes a rare earth metal or bismuth and wherein furthermore M' is an element selected from the group consisting of calcium, magnesium, strontium and barium.
Claim 5
Dependent Claim
91 words
A security document according to claim 1 wherein said coloring agent comprises a ferrimagnetic garnet compound of the general formula M 3-x M' x Fe 5-x M" x O 12 , wherein x has a value from 0 to 3, wherein M is an element selected from the group consisting of the rare earth metals and wherein furthermore M' is an element selected from the group consisting of calcium, strontium, barium, magnesium, zinc and cadmium and M" is an element selected from the group consisting of silicon, germanium, tin and tellurium.
Claim 6
Dependent Claim
70 words
A security document according to claim 1 wherein said coloring agent comprises a ferrimagnetic garnet compound of the general formula M 3 Fe 5-x M' x O 12 , wherein x has a value from 0 to 5, wherein M is an element selected from the group consisting of the rare earth metals and bismuth, and M' is an element selected from the group consisting of aluminium, gallium and indium.
Claim 7
Dependent Claim
19 words
A security document according to claim 1 wherein said given spectral region lies between 0.7 μm and 10 μm.
Claim 8
Dependent Claim
34 words
A security document according to claim 1 wherein said coloring agent comprises a ferrimagnetic garnet compound doped with rare earth metals such that, on excitation, said compound emits radiation in a predetermined spectral band.
Claim 9
Dependent Claim
16 words
A security document according to claim 1 wherein said coloring agent comprises a green ferromagnetic compound.
Claim 10
Dependent Claim
18 words
A security document according to claim 8 wherein the green ferromagnetic compound comprises iron borate FeBO 3 .
Claim 11
Dependent Claim
18 words
A security document according to claim 8 wherein the green ferromagnetic compound comprises iron fluoride FeF 3 .
Claim 12
Dependent Claim
20 words
A security document according to claim 1 wherein said coloring agent comprises a compound belonging to the group of ferrites.
Claim 13
Dependent Claim
25 words
A security document according to claim 11 wherein said compound belonging to the ferrites is Li 0 .5 Fe 2 .5 O 4 (lithium ferrite).
Claim 14
Dependent Claim
21 words
A security document according to claim 11 wherein said compound belonging to the ferrites is MgFe 2 O 4 (magnesium ferrite).
Claim 15
Dependent Claim
21 words
A security document according to claim 8 through 13 wherein said given spectral region lies between 0.7 μm and 10 μm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-01 | 1987-10-31 | 1988-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-01 | 1991-10-31 | 1992-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-01 | 1995-10-31 | 1996-05-01 | $7700.00 | Window Closed / Lapsed |