US4350883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of marking and of identifying objects marked by electrically conducting elements
Assignee: Imphy SA
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Filing: 1980-06-24
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Granted: 1982-09-21
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Expires: 2000-06-24
Abstract
Abstract A method of marking and of identifying objects (1) which are non-conductors of electricity by inclusion of conducting masses and detection by passage through a high-frequency electromagnetic field and detection of the variation in the corresponding response signal picked up. Metallic wires (2) each selected from a range of specimens of different electric conductivity are used as marking elements. The responses are measured which are each characteristic of one specimen and of a predetermined code value. The invention applies to the recognition of the authenticity of cards or documents thus previously marked.
Inventors
- 👤 Pierre Lagarde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:38
CPC Classifications
G; G06; G06K; G06K19/00; G06K19/06; G06K19/067; G06K1/00; G06K1/12; G06K7/00; G06K7/10; G06K7/10009
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
105 words
A methodfor identifying a non-metallic object, said object having a plurality of conductive members attached thereto, each of said members having a conductivity which form a unique code for said object, comprising: successively subjecting each of said members on said object to an alternating electromagnetic field whereby a current is successively induced in each of said members; detecting the intensity of a radiation component resulting from each of said members carrying a current induced by said field, said radiation component being distinctive of a radiating member; and recording each of said responses whereby a visual identification of said radiation components is provided identifying said object.
Claim 2
Dependent Claim
105 words
A methodfor identifying a non-metallic object, said object having a plurality of conductive members attached thereto, each of said members having a conductivity which form a unique code for said object, comprising: successively subjecting each of said members on said object to an alternating electromagnetic field whereby a current is successively induced in each of said members; detecting the intensity of a radiation component resulting from each of said members carrying a current induced by said field, said radiation component being distinctive of a radiating member; and recording each of said responses whereby a visual identification of said radiation components is provided identifying said object.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein said members are wires having a resistivity which varies along their length.
Claim 4
Dependent Claim
19 words
The new method of claim 2 wherein said electromagnetic field comprises first and second alternating fields having different frequencies.
Claim 5
Dependent Claim
21 words
The method of claim 2 wherein said electromagnetic field frequency is varied while each of said wires receives an induced current.
Claim 6
Independent Claim
27 words
A method as claimed in any one of the claims 2, 3, or 4 wherein the regions containing the wires are further subjected to a magnetic polarization.
Claim 7
Independent Claim
32 words
A method as claimed in any one of the claims 2, 3, or 4 wherein the wires while subject to said electromagnetic field are further subjected to heating above the Curie point.
Claim 8
Dependent Claim
13 words
The method of claim 2 wherein said wires are plated with different metals.
Claim 9
Independent Claim
109 words
A method for identifying a non-metallic object, said object including a plurality of conductive members, located apart from each other and having conductivity forming a unique code comprising: passing said object through an anechoic chamber at a constant orientation, said chamber having an entrance opening and exit opening for said object to pass; radiating said object as it passes through said chamber with a varying electromagnetic field, whereby each of said members successively receives an inducing current, and detecting the intensity of a radiation component emitted by each of said members as said object passes through said chamber whereby said individual components form a unique code for said object.
Claim 10
Independent Claim
109 words
A method for identifying a non-metallic object, said object including a plurality of conductive members, located apart from each other and having conductivity forming a unique code comprising: passing said object through an anechoic chamber at a constant orientation, said chamber having an entrance opening and exit opening for said object to pass; radiating said object as it passes through said chamber with a varying electromagnetic field, whereby each of said members successively receives an inducing current, and detecting the intensity of a radiation component emitted by each of said members as said object passes through said chamber whereby said individual components form a unique code for said object.
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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) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |