Patent US3704712A successfully refreshed from Google Patents.
US4882569A
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US
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Deactivatable fequency-dividing-transponder tag
Assignee: Sensormatic Electronics Corp
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Filing: 1988-07-26
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Granted: 1989-11-21
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Expires: 2008-07-26
Abstract
Abstract A presence-detection-system tag in which a frequency-dividing transponder may be decisively deactivated notwithstanding the intensity of the ambient magnetic field. The tag includes a frequency-dividing transponder including an active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency; a first bias strip of magnetic material disposed in relation to the active strip of magnetic material for biasing the active strip of magnetic material to be within the predetermined magnetic field intensity range only when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the active strip of magnetic material for further biasing the active strip to be outside of the predetermined magnetic field intensity range to thereby prevent the active strip of magnetic material from radiating electromagnetic radiation of the second predetermined frequency in response to excitation by electromagnetic radiation of the first predetermined frequency when the first and second bias strips of magnetic material are both magnetized. A coded tag includes two such active strips having different magnetomechanical resonant frequencies. Either tag may be detected in a presence detection system that includes means for transmitting an electromagnetic radiation signal of a first predetermined frequency into a surveillance zone; and means for detecting electromagnetic radiation of the second predetermined frequency within the surveillance zone. The system further includes a magnetizer for magnetizing the second bias strip to thereby deactivate the frequency-dividing transponder of the tag.
Inventors
- 👤 Subrata Dey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:25
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2408; G08B13/2411; G08B13/2428; G08B13/2437; G08B13/2442; G08B13/2448
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
190 words
A tag for attachment to an article to be detected within a surveillance zone, comprising a frequency-dividing transponder including an active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency, a first bias strip for magnetic material disposed in relation to the active strip of magnetic material for biasing the active strip of magnetic material to be within the predetermined magnetic field intensity range only when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the active strip of magnetic material for further biasing the active strip to be outside of the predetermined magnetic field intensity range to thereby prevent the active strip of magnetic material from radiating electromagnetic radiation of the second predetermined frequency in response to excitation by electromagnetic radiation of the first predetermined frequency when the first and second bias strip of magnetic material are both magnetized.
Claim 2
Dependent Claim
190 words
A tag for attachment to an article to be detected within a surveillance zone, comprising a frequency-dividing transponder including an active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency, a first bias strip for magnetic material disposed in relation to the active strip of magnetic material for biasing the active strip of magnetic material to be within the predetermined magnetic field intensity range only when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the active strip of magnetic material for further biasing the active strip to be outside of the predetermined magnetic field intensity range to thereby prevent the active strip of magnetic material from radiating electromagnetic radiation of the second predetermined frequency in response to excitation by electromagnetic radiation of the first predetermined frequency when the first and second bias strip of magnetic material are both magnetized.
Claim 3
Dependent Claim
20 words
A tag according to claim 1, wherein the first and second bias strip of magnetic material have different magnetic properties.
Claim 4
Dependent Claim
19 words
A tag according to claim 2, wherein the first and second bias strips of magnetic material have different dimensions.
Claim 5
Dependent Claim
19 words
A tag according to claim 1, wherein the first and second bias strips of magnetic material have different dimensions.
Claim 6
Dependent Claim
110 words
A tag according to claim 1, wherein the active strip of magnetic material is a thin, flat ribbon of low coercivity magnetostrictive amorphous magnetic material having a transverse uniaxial magnetic anisotropy defining a magnetomechanical resonant frequency "f 1 " equal to one-half the first predetermined frequency in accordance with the dimensions of the ribbon, wherein when the ribbon is in the presence of a magnetic bias field within the predetermined magnetic field intensity range, the ribbon responds to the detection of electromagnetic radiation of a frequency "2f 1 " by transmitting electromagnetic radiation of the second predetermined frequency, which is a frequency divided quotient of the frequency "2f 1 .
Claim 7
Dependent Claim
267 words
A coded tag for attachment to an article to be detected within a surveillance zone, comprising a first frequency-dividing transponder including a first active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency; a second frequency-dividing transponder including a second active strip of magnetic material that, when magnetically biased to be within the predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a third predetermined frequency by radiating electromagnetic radiation of a fourth predetermined frequency that is a frequencydivided quotient of the third predetermined frequency; a first bias strip of magnetic material disposed in relation to the first and second active strips of magnetic material for biasing the first and second active strips of magnetic material to be within the predetermined magnetic field intensity range when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the first and second active strips of magnetic material for further biasing the first and second active strips to be outside of the predetermined magnetic field intensity range to thereby prevent the first and second active strips of magnetic material from respectively radiating electromagnetic radiation of the second and fourth predetermined frequencies in response to excitation by electromagnetic radiation of the first and second predetermined frequencies when the first and second bias strips of magnetic material are both magnetized.
Claim 8
Dependent Claim
267 words
A coded tag for attachment to an article to be detected within a surveillance zone, comprising a first frequency-dividing transponder including a first active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency; a second frequency-dividing transponder including a second active strip of magnetic material that, when magnetically biased to be within the predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a third predetermined frequency by radiating electromagnetic radiation of a fourth predetermined frequency that is a frequencydivided quotient of the third predetermined frequency; a first bias strip of magnetic material disposed in relation to the first and second active strips of magnetic material for biasing the first and second active strips of magnetic material to be within the predetermined magnetic field intensity range when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the first and second active strips of magnetic material for further biasing the first and second active strips to be outside of the predetermined magnetic field intensity range to thereby prevent the first and second active strips of magnetic material from respectively radiating electromagnetic radiation of the second and fourth predetermined frequencies in response to excitation by electromagnetic radiation of the first and second predetermined frequencies when the first and second bias strips of magnetic material are both magnetized.
Claim 9
Dependent Claim
20 words
A tag according to claim 6, wherein the first and second bias strips of magnetic material have different magnetic properties.
Claim 10
Dependent Claim
19 words
A tag according to claim 7, wherein the first and second bias strips of magnetic material have different dimensions.
Claim 11
Dependent Claim
19 words
A tag according to claim 6, wherein the first and second bias strips of magnetic material have different dimensions.
Claim 12
Dependent Claim
218 words
A coded tag according to claim 6, wherein the first active strip of magnetic material is a thin, flat ribbon of low coercivity magnetostrictive amorphous magnetic material having a transverse uniaxial magnetic anisotropy defining a magnetomechanical resonant frequency "f 1 " equal to one-half the first predetermined frequency in accordance with the dimensions of the ribbon, wherein when the ribbon is in the presence of a magnetic bias field within the predetermined magnetic field intensity range, the ribbon responds to the detection of electromagnetic radiation of a frequency "2f 1 : by transmitting electromagnetic radiation of the second predetermined frequency, which is a frequency divided quotient of the frequency "2f 1 ; and wherein the second active strip of magnetic material is a thin, flat ribbon of low coercivity magnetostrictive amorphous magnetic material having a transverse uniaxial magnetic anisotropy defining a magnetomechanical resonant frequency "f 2 " equal to one-half the third predetermined frequency in accordance with the dimensions of the ribbon, wherein when the ribbon is in the presence of a magnetic bias field within the predetermined magnetic field intensity range, the ribbon responds to the detection of electromagnetic radiation of a frequency "2f 2 " by transmitting electromagnetic radiation of the fourth predetermined frequency, which is a frequency divided quotient of the frequency "2f 2 .
Claim 13
Dependent Claim
232 words
A presence detection system, comprising means for transmitting an electromagnetic radiation signal of a first predetermined frequency into a surveillance zone; a tag for attachment to an article to be detected within the surveillance zone, comprising a frequency-dividing transponder including an active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency; a first bias strip of magnetic material disposed in relation to the active strip of magnetic material for biasing the active strip of magnetic material to be within the predetermined magnetic field intensity range only when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the active strip of magnetic material for further biasing the active strip to be outside the predetermined magnetic field intensity range to thereby prevent the active strip of magnetic material from radiating electromagnetic radiation of the second predetermined frequency in response to excitation by electromagnetic radiation of the first predetermined frequency when the first and second bias strips of magnetic material are both magnetized. means for detecting electromagnetic radiation of the second predetermined frequency within the surveillance zone; and means for magnetizing the second bias strip.
Claim 14
Dependent Claim
232 words
A presence detection system, comprising means for transmitting an electromagnetic radiation signal of a first predetermined frequency into a surveillance zone; a tag for attachment to an article to be detected within the surveillance zone, comprising a frequency-dividing transponder including an active strip of magnetic material that, when magnetically biased to be within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency; a first bias strip of magnetic material disposed in relation to the active strip of magnetic material for biasing the active strip of magnetic material to be within the predetermined magnetic field intensity range only when the first bias strip of magnetic material is magnetized; and a second bias strip of magnetic material disposed in relation to the active strip of magnetic material for further biasing the active strip to be outside the predetermined magnetic field intensity range to thereby prevent the active strip of magnetic material from radiating electromagnetic radiation of the second predetermined frequency in response to excitation by electromagnetic radiation of the first predetermined frequency when the first and second bias strips of magnetic material are both magnetized. means for detecting electromagnetic radiation of the second predetermined frequency within the surveillance zone; and means for magnetizing the second bias strip.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-11-20 | 1993-05-22 | 1993-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-20 | 1997-05-22 | 1997-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-20 | 2001-05-22 | 2001-11-21 | $7700.00 | Window Closed / Lapsed |