US5237307A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-contact tamper sensing by electronic means
Assignee: United States Department of Energy
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Filing: 1991-11-27
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Granted: 1993-08-17
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Expires: 2011-11-27
Abstract
Abstract A tamper-sensing system for an electronic tag 10 which is to be fixed to a surface 11 of an article 12, the tamper-sensing system comprising a capacitor having two non-contacting, capacitively-coupled elements 16, 19. Fixing of the body to the article will establish a precise location of the capacitor elements 16 and 19 relative to each other. When interrogated, the tag will generate a tamper-sensing signal having a value which is a function of the amount of capacity of the capacitor elements. The precise relative location of the capacitor elements cannot be duplicated if the tag is removed and affixed to a surrogate article having a fiducial capacitor element 19 fixed thereto. A very small displacement, in the order of 2-10 microns, of the capacitor elements relative to each other if the tag body is removed and fixed to a surrogate article will result in the tamper-sensing signal having a different, and detectable, value when the tag is interrogated.
Inventors
- 👤 Dale G. Gritton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:48
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2414; G08B13/242; G08B13/2417; G08B13/2428; G08B13/2431; G08B13/2437; G08B13/2448; G08B29/00; G08B29/02; G08B29/04; G08B29/046
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
316 words
A tamper-sensing tag comprising: a tag body adapted to be fixed against movement relative to a surface of an article, a capacitor having at least one variable-capacity section with first and second elements, said first element being positionable relative to said second element at various positions, displaced from each other, said one variable-capacity section having different amounts of capacity when said first element is in its various positions, respectively, relative to said second element, means for generating a first signal which is a function of the amount of capacity of said one variable-capacity section, said first signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being adapted to be fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first position relative to each other, means in said tag for generating a second signal having a value unrelated to the amount of capacity of said one variable-capacity section, means in said tag for combining said first and second signals, means in said tag for encrypting said combined signals, means in said tag responsive to external interrogation of said tag for sending from said tag the encrypted combined signals in digital form, and wherein said means for generating said second signal has the function of changing the value of said second signal for each interrogation of said tag.
Claim 2
Dependent Claim
316 words
A tamper-sensing tag comprising: a tag body adapted to be fixed against movement relative to a surface of an article, a capacitor having at least one variable-capacity section with first and second elements, said first element being positionable relative to said second element at various positions, displaced from each other, said one variable-capacity section having different amounts of capacity when said first element is in its various positions, respectively, relative to said second element, means for generating a first signal which is a function of the amount of capacity of said one variable-capacity section, said first signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being adapted to be fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first position relative to each other, means in said tag for generating a second signal having a value unrelated to the amount of capacity of said one variable-capacity section, means in said tag for combining said first and second signals, means in said tag for encrypting said combined signals, means in said tag responsive to external interrogation of said tag for sending from said tag the encrypted combined signals in digital form, and wherein said means for generating said second signal has the function of changing the value of said second signal for each interrogation of said tag.
Claim 3
Dependent Claim
313 words
A tagged article comprising: an article having a surface, a tag body fixed against movement relative to said surface, a capacitor having at least one variable-capacity section with first and second elements, said first element being positionable relative to said second element at various positions, displaced from each other, said one variable-capacity section having various different amounts of capacity when said first element is in its various positions, respectively, relative to said second element, means for generating a first signal which is a function of the amount of capacity of said one variable-capacity section, said first signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first position relative to each other, means in said tag for generating a second signal having a value unrelated to the amount of capacity of said one variable-capacity section, means in said tag for combining said first and second signals, means in said tag for encrypting said combined signals, means in said tag responsive to external interrogation of said tag for sending from said tag for encrypted combined signals in digital form, and wherein said means for generating said second signal has the function of changing the value of said second signal for each interrogation of said tag.
Claim 4
Dependent Claim
313 words
A tagged article comprising: an article having a surface, a tag body fixed against movement relative to said surface, a capacitor having at least one variable-capacity section with first and second elements, said first element being positionable relative to said second element at various positions, displaced from each other, said one variable-capacity section having various different amounts of capacity when said first element is in its various positions, respectively, relative to said second element, means for generating a first signal which is a function of the amount of capacity of said one variable-capacity section, said first signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first position relative to each other, means in said tag for generating a second signal having a value unrelated to the amount of capacity of said one variable-capacity section, means in said tag for combining said first and second signals, means in said tag for encrypting said combined signals, means in said tag responsive to external interrogation of said tag for sending from said tag for encrypted combined signals in digital form, and wherein said means for generating said second signal has the function of changing the value of said second signal for each interrogation of said tag.
Claim 5
Dependent Claim
226 words
A tamper-sensing tag comprising: a tag body adapted to be fixed against movement relative to a surface of an article, a differential capacitor having a variable-capacity section with first and second parallel elements, said first element being laterally positionable relative to said second element at various lateral positions, displaced from each other, said variable-capacity section having various different amounts of capacity when said first element is in its various lateral positions, respectively, relative to said second element, means for generating a signal which is a function of the amount of capacity of said variable-capacity section, said signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being adapted to be fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being laterally positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first lateral position relative to each other.
Claim 6
Dependent Claim
226 words
A tamper-sensing tag comprising: a tag body adapted to be fixed against movement relative to a surface of an article, a differential capacitor having a variable-capacity section with first and second parallel elements, said first element being laterally positionable relative to said second element at various lateral positions, displaced from each other, said variable-capacity section having various different amounts of capacity when said first element is in its various lateral positions, respectively, relative to said second element, means for generating a signal which is a function of the amount of capacity of said variable-capacity section, said signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being adapted to be fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being laterally positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first lateral position relative to each other.
Claim 7
Dependent Claim
39 words
A tamper-sensing tag as set forth in claim 3 and further including: means responsive to external interrogation of said tag for sending from said tag digital information indicative of the value of said signal of said one variable-capacity section.
Claim 8
Dependent Claim
38 words
A tamper-sensing tag as set forth in claim 3 wherein said various positions of said first element relative to said second element are distinguishable when displaced from each other in the range of from 2 to 10 microns.
Claim 9
Dependent Claim
119 words
A tamper-sensing tag as set forth in claim 3 and further including: means in said tag for generating a second signal having a value unrelated to the amount of capacity of said one variable-capacity section, means in said tag for combining said second signal and said signal which is a function of the amount of capacity of said one variable-capacity section, means in said tag for encrypting said combined signals, means in said tag responsive to external interrogation of said tag for sending from said tag the encrypted combined signals in digital form, and wherein said means for generating said second signal has the function of changing the value of said second signal for each interrogation of said tag.
Claim 10
Dependent Claim
222 words
A tagged article comprising: an article having a surface, a tag body fixed against movement relative to said surface, a differential capacitor having a variable-capacity section with first and second parallel elements, said first element being laterally positionable relative to said second element at various lateral positions, displaced from each other, said variable-capacity section having various different amounts of capacity when said first element is in its various lateral positions, respectively, relative to said second element, means for generating a signal which is a function of the amount of capacity of said variable-capacity section, said signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being laterally positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first lateral position relative to each other.
Claim 11
Dependent Claim
222 words
A tagged article comprising: an article having a surface, a tag body fixed against movement relative to said surface, a differential capacitor having a variable-capacity section with first and second parallel elements, said first element being laterally positionable relative to said second element at various lateral positions, displaced from each other, said variable-capacity section having various different amounts of capacity when said first element is in its various lateral positions, respectively, relative to said second element, means for generating a signal which is a function of the amount of capacity of said variable-capacity section, said signal having various values distinguishable from each other when said first element is in its various positions, respectively, relative to said second element, one of said first and second elements being fixed against movement relative to said tag body, and the other of said first and second elements being fixed against movement relative to said surface of said article and with said first element being in a first position relative to said second element, said tag body and said other of said first and second elements being laterally positionable relative to each other on said article prior to said tag body's being fixed to said article so as to enable said elements to be fixed to said article in said first lateral position relative to each other.
Claim 12
Dependent Claim
34 words
A tagged article as set forth in claim 7 and further including: means responsive to external interrogation of said tag for sending from said tag digital information indicative of the value of said signal.
Claim 13
Dependent Claim
38 words
A tagged article as set forth in claim 7 wherein said various positions of said first element relative to said second element are distinguishable when displaced from each other in the range of from 2 to 10 microns.
Claim 14
Dependent Claim
117 words
A tagged article as set forth in claim 7 and further including: means in said tag for generating a second signal having a value unrelated to the amount of capacity of said variable-capacity section, means in said tag for combining said second signal and said signal which is a function of the amount of capacity of said variable-capacity section, means in said tag for encrypting said combined signals, means in said tag responsive to external interrogation of said tag for sending from said tag for encrypted combined signals in digital form, and wherein said means for generating said second signal has the function of changing the value of said second signal for each interrogation of said tag.
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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) | 1996-08-16 | 1997-02-15 | 1997-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-16 | 2001-02-15 | 2001-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-16 | 2005-02-15 | 2005-08-17 | $7700.00 | Window Closed / Lapsed |