US5538803A
Expired / Lapsed
US
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Multibit tag using Barkhausen effect
Assignee: Intermec IP Corp
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Filing: 1994-11-23
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Granted: 1996-07-23
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Expires: 2014-11-23
Abstract
Abstract An identification tag which can be encoded with multiple bits of information and can be remotely interrogated and read includes a plurality of magnetic elements. The information is stored in the magnetic elements which produce a large domain wall displacement (Barkhausen jump) at a particular magnetic field.
Inventors
- 👤 Richard J. Gambino
- 👤 Robert J. VON Gutfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:37
CPC Classifications
G; G06; G06K; G06K19/00; G06K19/06; G06K19/06187; G06K19/06196; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
137 words
A multibit identification tag for storing digital data, comprising: a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; and a hard magnetic layer deposited onto said first nonmagnetic spacer layer, a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field.
Claim 2
Dependent Claim
137 words
A multibit identification tag for storing digital data, comprising: a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; and a hard magnetic layer deposited onto said first nonmagnetic spacer layer, a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field.
Claim 3
Dependent Claim
116 words
A multibit identification tag for storing digital data, comprising; a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein.
Claim 4
Dependent Claim
116 words
A multibit identification tag for storing digital data, comprising; a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein.
Claim 5
Dependent Claim
125 words
A multibit identification tag for storing digital data, comprising: a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein, said at least one gap incorporating nonmagnetic material therein.
Claim 6
Dependent Claim
125 words
A multibit identification tag for storing digital data, comprising: a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein, said at least one gap incorporating nonmagnetic material therein.
Claim 7
Dependent Claim
30 words
A tag according to claim 3, wherein the thickness of said soft magnetic shunt path layer of a respective magnetic structure of said plurality of magnetic structures is selectively varied.
Claim 8
Dependent Claim
20 words
A tag according to claim 1 wherein the presence or absence of said discontinuous change in magnetization comprises a code.
Claim 9
Dependent Claim
13 words
A tag according to claim 5 wherein said code is a binary code.
Claim 10
Independent Claim
156 words
A method of constructing a multibit identification tag for storing digital data, said method comprising steps of: depositing Barkhausen jump magnetic material onto a substrate; depositing a first nonmagnetic spacer layer on said Barkhausen jump magnetic material layer, said Barkhausen jump magnetic material layer being demagnetized and annealed; depositing a hard magnetic layer over said first nonmagnetic spacer layer; depositing a second nonmagnetic spacer layer on said hard magnetic layer; and depositing a soft magnetic shunt path layer on said second nonmagnetic spacer layer, thereby to produce said multibit identification tag, said multibit identification tag comprising a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field and wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field.
Claim 11
Independent Claim
156 words
A method of constructing a multibit identification tag for storing digital data, said method comprising steps of: depositing Barkhausen jump magnetic material onto a substrate; depositing a first nonmagnetic spacer layer on said Barkhausen jump magnetic material layer, said Barkhausen jump magnetic material layer being demagnetized and annealed; depositing a hard magnetic layer over said first nonmagnetic spacer layer; depositing a second nonmagnetic spacer layer on said hard magnetic layer; and depositing a soft magnetic shunt path layer on said second nonmagnetic spacer layer, thereby to produce said multibit identification tag, said multibit identification tag comprising a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field and wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field.
Claim 12
Dependent Claim
22 words
A method as in claim 7, further comprising a step of magnetizing the hard magnetic layer by applying an external field thereto.
Claim 13
Dependent Claim
37 words
A method as in claim 8, further comprising steps of driving the hard magnetic layer to saturation, and decreasing the external field applied thereto to zero, thereby to leave the hard magnetic layer in its remanent state.
Claim 14
Dependent Claim
18 words
A method as in claim 7, wherein said soft magnetic shunt path layer is deposited in different thicknesses.
Claim 15
Dependent Claim
47 words
A method as in claim 7, wherein said step of depositing said soft magnetic shunt layer comprises a step of evenly depositing said soft magnetic layer, said method further comprising a step of heating designated portions of said soft magnetic material to render said designated portions nonmagnetic.
Claim 16
Dependent Claim
20 words
A method as in claim 11, wherein said step of heating includes a step of laser heating said designated portions.
Claim 17
Dependent Claim
24 words
A method as in claim 7, wherein said step of annealing includes annealing said active magnetic material layer at 300° C. for 30 minutes.
Claim 18
Dependent Claim
30 words
A method as in claim 7, wherein said step of depositing said Barkhausen jump magnetic material onto said substrate includes a step of sputter depositing said Barkhausen jump magnetic material.
Claim 19
Dependent Claim
17 words
A method as in claim 7, further comprising a step of maintaining said substrate at room temperature.
Claim 20
Dependent Claim
38 words
A method as in claim 7, wherein said soft magnetic shunt layer is one of a permalloy and a soft amorphous magnetic composition deposited below 200° C., further comprising a step of maintaining said substrate at room temperature.
Claim 21
Dependent Claim
19 words
A method as in claim 7, further comprising a step of adjusting a bias field on individual tag elements.
Claim 22
Dependent Claim
21 words
A method as in claim 7, further comprising a step of rendering portions of said soft magnetic shunt path layer nonmagnetic.
Claim 23
Independent Claim
159 words
A method of constructing a multibit identification tag for storing digital dam, said method comprising the steps of: depositing Barkhausen jump magnetic material onto a first substrate; depositing a first nonmagnetic spacer layer on said Barkhausen jump magnetic material layer, said Barkhausen jump magnetic material layer being demagnetized and annealed; depositing a hard magnetic layer over said first nonmagnetic spacer layer; depositing a second nonmagnetic spacer layer on said hard magnetic layer; and providing a soft magnetic shunt path layer on said second nonmagnetic spacer layer, thereby to produce said multibit identification tag, said multibit identification tag comprising: a first substrate; an Barkhausen jump magnetic material deposited on said first substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer.
Claim 24
Independent Claim
159 words
A method of constructing a multibit identification tag for storing digital dam, said method comprising the steps of: depositing Barkhausen jump magnetic material onto a first substrate; depositing a first nonmagnetic spacer layer on said Barkhausen jump magnetic material layer, said Barkhausen jump magnetic material layer being demagnetized and annealed; depositing a hard magnetic layer over said first nonmagnetic spacer layer; depositing a second nonmagnetic spacer layer on said hard magnetic layer; and providing a soft magnetic shunt path layer on said second nonmagnetic spacer layer, thereby to produce said multibit identification tag, said multibit identification tag comprising: a first substrate; an Barkhausen jump magnetic material deposited on said first substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer.
Claim 25
Dependent Claim
46 words
A method as in claim 19, wherein said soft magnetic shunt path layer is first deposited on a second substrate and said substrate/shunt layer is attached to said second nonmagnetic spacer layer and wherein the thicknesses of said shunt layer is varied within said multibit tag.
Claim 26
Dependent Claim
68 words
An identification tag for storing multi-bit digital data, comprising: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer.
Claim 27
Dependent Claim
68 words
An identification tag for storing multi-bit digital data, comprising: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer.
Claim 28
Dependent Claim
82 words
An identification tag for storing multi-bit digital data, comprising: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein.
Claim 29
Dependent Claim
82 words
An identification tag for storing multi-bit digital data, comprising: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein.
Claim 30
Dependent Claim
91 words
An identification tag for storing multi-bit digital data, comprising: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein, said at least one gap incorporating nonmagnetic material therein.
Claim 31
Dependent Claim
91 words
An identification tag for storing multi-bit digital data, comprising: a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein, said at least one gap incorporating nonmagnetic material therein.
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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) | 1999-07-23 | 2000-01-22 | 2000-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-23 | 2004-01-22 | 2004-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-23 | 2008-01-22 | 2008-07-23 | $7700.00 | Window Closed / Lapsed |