US5680106A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multibit tag with stepwise variable frequencies
Assignee: Intermec IP Corp
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Filing: 1995-10-27
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Granted: 1997-10-21
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Expires: 2015-10-27
Abstract
Abstract A transponder is disclosed comprising a resonant RLC circuit with one or more components that can be connected or disconnected non-destructively using switches that respond to an externally applied magnetic field. The switching in or out of the components causes a change in the resonant frequency of the original RLC circuit that is detected by the base station sweeping a carrier signal through a range of frequencies to detect a returned signal that changes when the carrier signal frequency matches the resonant frequency of the resonant circuit/tag. The resonant frequency changes when one or more of the circuit components is connected or disconnected. Each switch transfers at a unique magnetic field intensity so that electrical contact is achieved at a predetermined value of an externally applied magnetic field. The detected changes are used to create a code that is used to pass information from the resonant circuit/tag to the base station.
Inventors
- 👤 Alejandro Gabriel Schrott
- 👤 Richard Joseph Gambino
- 👤 Robert Jacob von Gutfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:36
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2414; G08B13/242; G06; G06K; G06K19/00; G06K19/06; G06K19/067; G06K19/0672; G08B13/2417; G08B13/2428; G08B13/2431; G08B13/2465; G08B13/2482
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
67 words
A transponder comprising: a resonant circuit having two or more circuit components that determine a resonance frequency of the circuit; and one or more switches, each of the switches transferring at a respective threshold intensity of a local magnetic field created by an externally applied, ramping magnetic field, the resonant frequency of the circuit shifting to a next resonant frequency each time one of the switches transfers.
Claim 2
Dependent Claim
67 words
A transponder comprising: a resonant circuit having two or more circuit components that determine a resonance frequency of the circuit; and one or more switches, each of the switches transferring at a respective threshold intensity of a local magnetic field created by an externally applied, ramping magnetic field, the resonant frequency of the circuit shifting to a next resonant frequency each time one of the switches transfers.
Claim 3
Dependent Claim
29 words
A transponder, as in claim 1, where one or more of the switches shifts the resonant frequency by connecting one or more added circuit components to the resonant circuit.
Claim 4
Dependent Claim
18 words
A transponder, as in claim 2, where one or more of the added circuit components is a capacitor.
Claim 5
Dependent Claim
18 words
A transponder, as in claim 2, where one or more of the added circuit components is an inductor.
Claim 6
Dependent Claim
29 words
A transponder, as in claim 1, where one or more of the switches shifts the resonant frequency by disconnecting one or more deleted circuit components from the resonant circuit.
Claim 7
Dependent Claim
18 words
A transponder, as in claim 5, where one or more of the deleted circuit components is a capacitor.
Claim 8
Dependent Claim
18 words
A transponder, as in claim 5, where one or more of the deleted circuit components is an inductor.
Claim 9
Dependent Claim
17 words
A transponder, as in claim 1, where one or more of the switches is a reed switch.
Claim 10
Dependent Claim
53 words
A transponder, as in claim 8, where the reed switch has a first and a second soft magnetic element separated by a gap and the local magnetic field having an intensity greater than the threshold causes the gap to close to establish an electrical contact between the first and second soft magnetic elements.
Claim 11
Dependent Claim
36 words
A transponder, as in claim 9, where the reed switch also has a hard magnetic element providing a bias to the first and second soft magnetic elements to change the threshold at which the gap closes.
Claim 12
Dependent Claim
76 words
A transponder, as in claim 1, where one or more of the switches has a first magnetostrictive element with an attached end and a free end, the free end separated by a gap from a contact, and the local magnetic field ramping in intensity in a first direction causing the first magnetostrictive element to change in length so that the free end electrically connects with the contact when the local magnetic field passes through the threshold.
Claim 13
Dependent Claim
32 words
A transponder, as in claim 11, where the free end electrically disconnects with the contact when the local magnetic field ramps in intensity in a second direction and passes through the threshold.
Claim 14
Dependent Claim
26 words
A transponder, as in claim 11, further comprising a hard magnetic element that changes the threshold at which the free end electrically connects with the contact.
Claim 15
Dependent Claim
80 words
A transponder, as in claim 1, where one or more of the switches has a first and second magnetostrictive element, each with an attached end and a free end, the free ends separated by a gap, and the local magnetic field ramping in intensity in a first direction causes the first and second magnetostrictive elements to change in length so that the gap closes and the free ends make electrical contact when the local magnetic field passes through the threshold.
Claim 16
Dependent Claim
32 words
A transponder, as in claim 14, where the gap opens when the local magnetic field ramping in intensity in a second direction passes through the threshold to electrically disconnect the free ends.
Claim 17
Dependent Claim
21 words
A transponder, as in claim 14, further comprising a hard magnetic element that changes the threshold at which the gap closes.
Claim 18
Dependent Claim
63 words
A transponder, as in claim 1, where one or more of the switches has a bimorph element with an attached end and a free end, the free end separated by a gap from a contact, and the local magnetic field ramping in intensity causing the bimorph element to bend so that the switch transfers when the local magnetic field passes through the threshold.
Claim 19
Dependent Claim
68 words
A transponder, as in claim 1, where one or more of the switches has a first and a second bimorph element each with an attached end and a free end, the free ends separated by a gap from one another, and the local magnetic field ramping in intensity causing the bimorph elements to bend so that the switch transfers when the local magnetic field passes through the threshold.
Claim 20
Dependent Claim
33 words
A transponder, as in claim 1, where one or more of the switches has two or more elements capable of making electrical contact, each of the elements positioned non parallel to one another.
Claim 21
Dependent Claim
34 words
A transponder, as in claim 1, where one or more of the switches is a master switch that is capable of electrically connecting and disconnecting one or more other switches to the resonant circuit.
Claim 22
Independent Claim
124 words
A method of communication with a transponder in a field of a base station, comprising the steps of: ramping a magnetic field; sweeping a radio frequency carrier through a frequency range at a sweep frequency simultaneously with the magnetic field, the frequency range including a set of frequencies called a frequency set; sensing a return signal, being a background signal, when the radio frequency carrier is not at one of the frequencies in the frequency set; sensing the return signal, being a resonance frequency, when the radio frequency carrier is at one of the frequencies in the frequency set; and storing a code that indicates if the resonance frequency is different from the background signal at each of the frequencies in the frequency set.
Claim 23
Independent Claim
124 words
A method of communication with a transponder in a field of a base station, comprising the steps of: ramping a magnetic field; sweeping a radio frequency carrier through a frequency range at a sweep frequency simultaneously with the magnetic field, the frequency range including a set of frequencies called a frequency set; sensing a return signal, being a background signal, when the radio frequency carrier is not at one of the frequencies in the frequency set; sensing the return signal, being a resonance frequency, when the radio frequency carrier is at one of the frequencies in the frequency set; and storing a code that indicates if the resonance frequency is different from the background signal at each of the frequencies in the frequency set.
Claim 24
Independent Claim
225 words
A system for interrogating one or more transponders, comprising: a resonant circuit in the transponder having two or more circuit components that determine a resonance frequency of the circuit and one or more switches, each of the switches capable of transferring to electrically connect and disconnect one or more switched circuit components to the resonant circuit, the switched circuit components shifting the resonance frequency of the resonant circuit to a next resonant frequency when the switch transfers; a base station further comprising: an emitter unit that ramps a magnetic field to cause a range of local magnetic field intensities at a location of the transponder and simultaneously sweeps a radio frequency carrier through a frequency range, the frequency range having one or more frequencies in a frequency set; a detection unit that detects a return signal from the transponder, the return signal being a background signal when the radio frequency carrier is not at one of the frequencies in the frequency set and a resonant frequency signal when the radio frequency carrier is at one of the frequencies in the frequency set; and a memory storing a code that indicates that the resonant frequency signal is different than the background signal at one or more frequencies in the frequency set when the switch transfers because the local magnetic field has passed through a threshold intensity.
Claim 25
Independent Claim
225 words
A system for interrogating one or more transponders, comprising: a resonant circuit in the transponder having two or more circuit components that determine a resonance frequency of the circuit and one or more switches, each of the switches capable of transferring to electrically connect and disconnect one or more switched circuit components to the resonant circuit, the switched circuit components shifting the resonance frequency of the resonant circuit to a next resonant frequency when the switch transfers; a base station further comprising: an emitter unit that ramps a magnetic field to cause a range of local magnetic field intensities at a location of the transponder and simultaneously sweeps a radio frequency carrier through a frequency range, the frequency range having one or more frequencies in a frequency set; a detection unit that detects a return signal from the transponder, the return signal being a background signal when the radio frequency carrier is not at one of the frequencies in the frequency set and a resonant frequency signal when the radio frequency carrier is at one of the frequencies in the frequency set; and a memory storing a code that indicates that the resonant frequency signal is different than the background signal at one or more frequencies in the frequency set when the switch transfers because the local magnetic field has passed through a threshold intensity.
Claim 26
Dependent Claim
80 words
A transponder comprising: a resonant circuit means for resonating at two or more resonant frequencies, the resonant circuit means having two or more circuit components that determine a resonance frequency of the circuit; and one or more switch means for transferring at a respective threshold intensity of a local magnetic field created by an externally applied, ramping magnetic field, the resonant frequency of the circuit shifting to a next resonant frequency each time one or more of the switches transfers.
Claim 27
Dependent Claim
80 words
A transponder comprising: a resonant circuit means for resonating at two or more resonant frequencies, the resonant circuit means having two or more circuit components that determine a resonance frequency of the circuit; and one or more switch means for transferring at a respective threshold intensity of a local magnetic field created by an externally applied, ramping magnetic field, the resonant frequency of the circuit shifting to a next resonant frequency each time one or more of the switches transfers.
Claim 28
Independent Claim
246 words
A system for interrogating one or more transponders, comprising: a resonant circuit means for resonating at two or more resonant frequencies, the resonant circuit means being in the transponder and having two or more circuit components that determine the resonance frequency of the circuit and one or more switch means, each of the switch means capable of transferring to electrically connect and disconnect one or more switched circuit components to the resonant circuit means, the switched circuit components shifting the resonance frequency of the resonant circuit to a next resonant frequency when the switch means transfers; a base station further comprising: an emitter means for ramping a magnetic field to cause a range of local magnetic field intensities at a location of the transponder and simultaneously sweeps a radio frequency carrier through a frequency range, the frequency range having one or more frequencies in a frequency set; a detection means for detecting a return signal from the transponder, the return signal being a background signal when the radio frequency carrier is not at one of the frequencies in the frequency set and a resonant frequency signal when the radio frequency carrier is at one of the frequencies in the frequency set; and a memory means for storing a code that indicates that the resonant frequency signal is different than the background signal at one or more frequencies in the frequency set when the switch transfers because the local magnetic field has passed through a threshold intensity.
Claim 29
Independent Claim
246 words
A system for interrogating one or more transponders, comprising: a resonant circuit means for resonating at two or more resonant frequencies, the resonant circuit means being in the transponder and having two or more circuit components that determine the resonance frequency of the circuit and one or more switch means, each of the switch means capable of transferring to electrically connect and disconnect one or more switched circuit components to the resonant circuit means, the switched circuit components shifting the resonance frequency of the resonant circuit to a next resonant frequency when the switch means transfers; a base station further comprising: an emitter means for ramping a magnetic field to cause a range of local magnetic field intensities at a location of the transponder and simultaneously sweeps a radio frequency carrier through a frequency range, the frequency range having one or more frequencies in a frequency set; a detection means for detecting a return signal from the transponder, the return signal being a background signal when the radio frequency carrier is not at one of the frequencies in the frequency set and a resonant frequency signal when the radio frequency carrier is at one of the frequencies in the frequency set; and a memory means for storing a code that indicates that the resonant frequency signal is different than the background signal at one or more frequencies in the frequency set when the switch transfers because the local magnetic field has passed through a threshold intensity.
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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) | 2000-10-20 | 2001-04-21 | 2001-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-10-20 | 2005-04-21 | 2005-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-10-20 | 2009-04-21 | 2009-10-21 | $7700.00 | Window Closed / Lapsed |