US3878367A
Expired / Lapsed
US
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Magnetic security document and method for making same
Assignee: 3M Co
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Filing: 1973-05-02
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Granted: 1975-04-15
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Expires: 1993-05-02
Abstract
Abstract A security document having a magnetic recording layer containing uniformly dispersed magnetizable material having magnetic anisotropy wherein the material at a plurality of selected locations is differently physically aligned with respect to a reference location to provide a magnetically detectable permanent fixed information pattern such as a code pattern useful for authenticating the document. The document is authenticated in the following manner. A magnetic field is applied to the document to cause the material within the plurality of selected locations to be differently magnetized according to the physical alignment thereof. The differently magnetized selected locations are subsequently sensed by traversing the document past a sensor device to provide a signal representative of the plurality of selected locations. This signal is compared with a predetermined signal pattern to authenticate the document. A method for making such a security document includes, providing a sheet having a nonmagnetic backing and a layer thereon of a substantially uniform dispersion of magnetically anisotropic magnetizable particles wherein the particles are temporarily free to rotate, physically aligning the magnetizable particles at selected locations by applying magnetic fields to form a fixed information pattern; and then immobilizing the particles to provide a permanent magnetically detectable fixed information pattern. Visible indicia characteristic of an intended use of the document, are applied to the sheet.
Inventors
- 👤 Richard E Fayling
- 👤 Douglas D Campbell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:36
CPC Classifications
G; G06; G06K; G06K19/00; G06K19/06; G06K19/08; G06K19/10; G06K19/12; Y; Y10; Y10S; Y10S283/00; Y10S283/904
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
69 words
A security document having visible indicia characterisTic of an intended use thereof, which document includes a magnetic recording layer comprising uniformly dispersed magnetizable material having magnetic anisotropy, wherein the magnetizable material at a plurality of selected locations in the layer is differently physically aligned from the physical alignment of the magnetizable material at a reference location in the layer to provide a magnetically detectable permanent fixed information code pattern.
Claim 2
Dependent Claim
69 words
A security document having visible indicia characterisTic of an intended use thereof, which document includes a magnetic recording layer comprising uniformly dispersed magnetizable material having magnetic anisotropy, wherein the magnetizable material at a plurality of selected locations in the layer is differently physically aligned from the physical alignment of the magnetizable material at a reference location in the layer to provide a magnetically detectable permanent fixed information code pattern.
Claim 3
Dependent Claim
15 words
A security document according to claim 1, wherein the magnetizable material is particulate barium ferrite.
Claim 4
Dependent Claim
29 words
A security document according to claim 1, wherein the selected locations form a repetitive pattern defining a permanent signal track from which a predetermined repetitive signal may be produced.
Claim 5
Dependent Claim
45 words
A security document according to claim 3, wherein the repetitive pattern consists of adjacent selected locations within each of which the magnetizable material is differently physically aligned to define a continuously varying permanent signal track from which a predetermined continously varying signal may be produced.
Claim 6
Dependent Claim
54 words
A security document according to claim 1, wherein the magnetizable material in the remainder of the layer outside said selected locations is physically aligned in a single direction and the magnetizable material at more than two selected locations in a region not to be used for recording is differently aligned from said single direction.
Claim 7
Dependent Claim
42 words
A security document according to claim 5, wherein each of said selected locations consists of a discrete section within which the magnetizable material is physically aligned perpendicular to the direction of physical alignment of the material in the remainder of the layer.
Claim 8
Dependent Claim
29 words
A security document according to claim 1, wherein the selected locations form a non-repetitive pattern defining a permanent signal track from which a predetermined non-repetitive signal may be produced.
Claim 9
Independent Claim
102 words
A method for making a security document having a magnetically detectable permanent fixed information code pattern comprising providing a sheet having a nonmagnetic backing and a layer thereon of a substantially uniform dispersion of magnetically anisotropic magnetizable particles wherein the particles are temporarily free to rotate, causing the magnetizable particles at selected locations defining a permanent fixed information code pattern in the layer to be differently physically aligned from the physical alignment of the magnetizable particles at a reference location; and subsequently permanently immobilizing the particles, and applying to said sheet visible indicia characteristic of an intended use of the security document.
Claim 10
Independent Claim
102 words
A method for making a security document having a magnetically detectable permanent fixed information code pattern comprising providing a sheet having a nonmagnetic backing and a layer thereon of a substantially uniform dispersion of magnetically anisotropic magnetizable particles wherein the particles are temporarily free to rotate, causing the magnetizable particles at selected locations defining a permanent fixed information code pattern in the layer to be differently physically aligned from the physical alignment of the magnetizable particles at a reference location; and subsequently permanently immobilizing the particles, and applying to said sheet visible indicia characteristic of an intended use of the security document.
Claim 11
Dependent Claim
25 words
A method according to claim 8, wherein the magnetizable particles are physically aligned at the selected locations by applying magnetic fields at the selected locations.
Claim 12
Dependent Claim
22 words
A method according to claim 8, wherein said sheet is provided with a layer containing magnetically anisotropic magnetizable particles of barium ferrite.
Claim 13
Independent Claim
111 words
A system for making a security document having a magnetically detectable permanent fixed information code pattern comprising means for providing a sheet having a nonmagnetic backing and a layer thereon of a substantially uniform dispersion of magnetically anisotropic magnetizable particles wherein the particles are at least temporarily free to rotate, means for causing the magnetizable particles at selected locations defining a permanent fixed information code pattern in the layer to be differently physically aligned from the physical alignment of the magnetizable particles at a reference location and for subsequently permanently immobilizing the particles, and means for applying to said sheet visible indicia characteristic of an intended use of the security document.
Claim 14
Independent Claim
111 words
A system for making a security document having a magnetically detectable permanent fixed information code pattern comprising means for providing a sheet having a nonmagnetic backing and a layer thereon of a substantially uniform dispersion of magnetically anisotropic magnetizable particles wherein the particles are at least temporarily free to rotate, means for causing the magnetizable particles at selected locations defining a permanent fixed information code pattern in the layer to be differently physically aligned from the physical alignment of the magnetizable particles at a reference location and for subsequently permanently immobilizing the particles, and means for applying to said sheet visible indicia characteristic of an intended use of the security document.
Claim 15
Dependent Claim
39 words
A system according to claim 11, wherein said means for causing said particles to be differently physically aligned comprises means for applying magnetic fields upon the layer at selected locations to physicallY align the magnetizable particles within said locations.
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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) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |