US5764138A
Expired / Lapsed
US
⏱️ 0.0 years remaining
RF identification system for providing static data and one bit of variable data representative of an external stimulus
Assignee: Assa Abloy AB
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Filing: 1994-04-29
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Granted: 1998-06-09
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Expires: 2014-04-29
Abstract
Abstract An RF identification system for generating data indicative of an item that is tagged, and one bit of variable data representative of an external stimulus. An ID code reader is provided and an RF identification tag is coupled to the item that is to be monitored and the ID code reader queries the tag. The tag comprises two RF transponder chips that store a data relating to the item, and an excitation coil coupled thereto. A switch is coupled to the chips and excitation coil, and a capacitor is coupled across the switch. A sensor is coupled to the switch for generating one bit of variable data representative of an external stimulus, such as the pressure in a tire. The ID code reader comprises an exciter and RF excitation coil, and a receiver and an RF receiver coil. The receiver includes phase detection circuitry for detecting a state of the switch by detecting the phase shift between signals received from each of the transponder chips. When the switch is shorted, the effect of the capacitor is nullified. When the switch is is open, then the return signal from the second transponder chip has a small phase shift with respect to the signal from the first transponder chip. The phase detection circuitry detects this phase shift and determines the state of the switch. The system permits the use of an RF identification tag in remote or inaccessible positions to determine the state of a variable (the position of the switch) and store identification data. An example of this is an identification tag in a vehicle tire that stores the tire ID and also enables the reading of a pressure switch to confirm adequate tire pressure.
Inventors
- 👤 Peter R. Lowe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:36
CPC Classifications
B; B60; B60C; B60C23/00; B60C23/02; B60C23/04; B60C23/0408; B60C23/0422; B60C23/0433; B60C23/0435; B60C23/0438; B60C23/0442; G; G06; G06K; G06K19/00; G06K19/06; G06K19/067; G06K19/07; G06K19/077; G06K19/07749; G06K19/07758; G06K19/07764
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
191 words
An RF identification system for generating data indicative of an item that is tagged, and one bit of variable data representative of an external stimulus, said system comprising: an RF identification tag coupled to the item that is to be monitored that comprises: first and second RF transponder chips that each store data relating to the item that is to be monitored and that each comprise first and second antenna outputs; an excitation coil having one input coupled to respective first antenna outputs of the first and second RF transponder chips; a switch coupled between respective second antenna outputs of the first and second RF transponder chips and coupled to a second input of the excitation coil; a capacitor coupled across the switch; and a sensor coupled to the switch for generating one bit of variable data representative of an external stimulus; and an ID code reader that comprises: an exciter; an RF excitation coil coupled to the exciter; a receiver comprising an RF receiver coil and phase detection circuitry for detecting a state of the switch by detecting the phase shift between signals received from each of the transponder chips.
Claim 2
Dependent Claim
191 words
An RF identification system for generating data indicative of an item that is tagged, and one bit of variable data representative of an external stimulus, said system comprising: an RF identification tag coupled to the item that is to be monitored that comprises: first and second RF transponder chips that each store data relating to the item that is to be monitored and that each comprise first and second antenna outputs; an excitation coil having one input coupled to respective first antenna outputs of the first and second RF transponder chips; a switch coupled between respective second antenna outputs of the first and second RF transponder chips and coupled to a second input of the excitation coil; a capacitor coupled across the switch; and a sensor coupled to the switch for generating one bit of variable data representative of an external stimulus; and an ID code reader that comprises: an exciter; an RF excitation coil coupled to the exciter; a receiver comprising an RF receiver coil and phase detection circuitry for detecting a state of the switch by detecting the phase shift between signals received from each of the transponder chips.
Claim 3
Dependent Claim
13 words
The RF identification system of claim 1 wherein the item comprises a tire.
Claim 4
Dependent Claim
14 words
The RF identification system of claim 1 wherein the sensor comprises a pressure sensor.
Claim 5
Dependent Claim
13 words
The RF identification system of claim 3 wherein the item comprises a tire.
Claim 6
Dependent Claim
27 words
The RF identification system of claim 2 wherein the one bit of variable data representative of the external stimulus is representative of the pressure in the tire.
Claim 7
Dependent Claim
27 words
The RF identification system of claim 4 wherein the one bit of variable data representative of the external stimulus is representative of the pressure in the tire.
Claim 8
Dependent Claim
203 words
In an RF identification system that comprises an RF identification tag coupled to the item that is to be monitored for generating data indicative of the item, and an ID code reader comprising an exciter, an RF excitation coil coupled to the exciter, and a receiver comprising an RF receiver coil and phase detection circuitry for detecting a state of the switch by detecting the phase shift between signals received from identification tag, wherein the improvement comprises an RF identification tag for generating the data indicative of the item, and one bit of variable data representative of an external stimulus, said identification tag comprising: first and second RF transponder chips that each store data relating to the item that is to be monitored and that each comprise first and second antenna outputs; an excitation coil having one input coupled to respective first antenna outputs of the first and second RF transponder chips; a switch coupled between respective second antenna outputs of the first and second RF transponder chips and coupled to a second input of the excitation coil; a capacitor coupled across the switch; and a sensor coupled to the switch for generating one bit of variable data representative of the external stimulus.
Claim 9
Dependent Claim
203 words
In an RF identification system that comprises an RF identification tag coupled to the item that is to be monitored for generating data indicative of the item, and an ID code reader comprising an exciter, an RF excitation coil coupled to the exciter, and a receiver comprising an RF receiver coil and phase detection circuitry for detecting a state of the switch by detecting the phase shift between signals received from identification tag, wherein the improvement comprises an RF identification tag for generating the data indicative of the item, and one bit of variable data representative of an external stimulus, said identification tag comprising: first and second RF transponder chips that each store data relating to the item that is to be monitored and that each comprise first and second antenna outputs; an excitation coil having one input coupled to respective first antenna outputs of the first and second RF transponder chips; a switch coupled between respective second antenna outputs of the first and second RF transponder chips and coupled to a second input of the excitation coil; a capacitor coupled across the switch; and a sensor coupled to the switch for generating one bit of variable data representative of the external stimulus.
Claim 10
Dependent Claim
13 words
The RF identification system of claim 7 wherein the item comprises a tire.
Claim 11
Dependent Claim
14 words
The RF identification system of claim 7 wherein the sensor comprises a pressure sensor.
Claim 12
Dependent Claim
13 words
The RF identification system of claim 9 wherein the item comprises a tire.
Claim 13
Dependent Claim
27 words
The RF identification system of claim 8 wherein the one bit of variable data representative of the external stimulus is representative of the pressure in the tire.
Claim 14
Dependent Claim
27 words
The RF identification system of claim 10 wherein the one bit of variable data representative of the external stimulus is representative of the pressure in the tire.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-08 | 2001-12-08 | 2002-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-08 | 2005-12-08 | 2006-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-08 | 2009-12-08 | 2010-06-09 | $7700.00 | Window Closed / Lapsed |