RFID Condition Latching
First Claim
1. A radio-frequency identification (RFID) tag for use with an RFID reader that transmits RF signals to the RFID tag via a RF communication path, comprising:
- an RFID integrated circuit (IC) chip electrically coupled to a RF antenna system and adapted to be externally powered by the RF signals;
an energy storage device operably coupled to the RFID IC chip and adapted to store energy from the RF signals;
a switch operably coupled to the RFID IC chip and configured to be placed in either an ON state or an OFF state; and
a memory device operably coupled to the switch and the energy storage device and powered by the energy device so as to store switch-state information when the RFID IC chip is inadequately externally powered so that when the RFID IC chip is adequately externally powered it allows the tag antenna system to communicate a RF switch-state signal representative of the stored switch-state information.
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Accused Products
Abstract
A passive radio-frequency identification (RFID) system has an RFID reader that communicates with and provides power to an RFID tag. The RFID tag has an RFID integrated circuit chip that contains a memory device for storing information to be transmitted to the RFID reader, and energy storage device that stores energy for powering the integrated circuit chip. In the event that the RFID tag is activated during periods when the RFID integrated circuit chip is not receiving sufficient energy from the RFID reader, then either an energy storage device is provided to allow the activation event to be recorded at the RFID integrated circuit chip, or a memory device is provided that senses and records the activation event and communicates this activation event once power has been restored.
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Citations
23 Claims
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1. A radio-frequency identification (RFID) tag for use with an RFID reader that transmits RF signals to the RFID tag via a RF communication path, comprising:
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an RFID integrated circuit (IC) chip electrically coupled to a RF antenna system and adapted to be externally powered by the RF signals; an energy storage device operably coupled to the RFID IC chip and adapted to store energy from the RF signals; a switch operably coupled to the RFID IC chip and configured to be placed in either an ON state or an OFF state; and a memory device operably coupled to the switch and the energy storage device and powered by the energy device so as to store switch-state information when the RFID IC chip is inadequately externally powered so that when the RFID IC chip is adequately externally powered it allows the tag antenna system to communicate a RF switch-state signal representative of the stored switch-state information. - View Dependent Claims (2, 3, 4, 5)
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6. A passive radio-frequency identification (RFID) tag for use with an RFID reader that transmits RF signals to the RFID tag via a RF communication path, comprising:
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an RFID IC chip electrically coupled to a RF antenna system and adapted to be externally powered by the RF signals; a latching memory device capable of moving from a first state to a second state upon an activation event to the RFID tag, even when this activation event occurs when power is interrupted between the RFID reader and the RFID IC chip, such that when the RFID IC chip is adequately externally powered it allows the tag antenna system to communicate a RF signal representative of the stored second state information. - View Dependent Claims (7, 8, 9, 10, 11, 23)
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12. A passive RFID system comprising:
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an RFID reader having an RFID reader antenna capable of transmitting an RF signal, and an RFID tag comprising; an RFID integrated circuit chip containing a memory device for storing information to be communicated to the RFID reader, an RFID tag antenna coupled to the RFID integrated circuit chip, capable of communicating an RFID response signal to the RFID reader, an energy storage device that stores energy for powering the memory device, the energy storage device being electrically coupled to the integrated circuit chip, wherein the energy storage device is selected so as to store energy from the RF interrogation signal to power the memory device in the event that power to the RFID integrated circuit is interrupted, and a condition sensing device having a first state and a second state, the condition sensing device being electrically connected to the RFID tag, and wherein the condition sensing device may be switched from the first state to the second state. - View Dependent Claims (13, 14, 15)
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16. A passive RFID system comprising:
an RFID reader having an RFID reader antenna capable of transmitting an RF signal, and an RFID tag comprising; an RFID integrated circuit chip, an RFID tag antenna coupled to the RFID integrated circuit chip, capable of receiving energy from the RF signal, a memory device for storing information to be transmitted to the RFID reader, the memory device having a first state and a second activated state, and being operably connected to the RFID integrated circuit chip, and where the RFID tag antenna coupled to the RFID integrated circuit chip is capable of communicating an RFID response signal to the RFID reader, wherein the memory device is capable of recording a change from its first state to its second activated state during periods when the energy from the RF signal is insufficient to cause the RFID integrated circuit chip to record the change in memory device states. - View Dependent Claims (17, 18, 19, 20, 21)
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22. In an RFID system providing a method for communicating an activation event that has occurred during a period of time in which power has been interrupted between an RFID reader and an RFID tag, comprising the steps of:
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a. powering a first electric capacitor that is electrically attached to an RFID integrated circuit chip associated with the RFID tag, such that the first electric capacitor is placed in a charged state, b. simultaneously powering a second electrical capacitor that is also attached to the RFID integrated circuit chip of the RFID tag, such that the second electric capacitor is likewise placed in a charged state, c. switching a memory device from a first state to a second activated state, but in so doing, interrupting an RF signal to the RFID tag, and thereby interrupting power to the RFID tag, d. discharging the first electric capacitor upon switching the memory device to the second activated state, thereby moving the first electric capacitor from a charged stated to a second discharged stated, e. upon restoring power to the RFID integrated circuit chip, comparing the first electric capacitor to the second electric capacitor, and if the first electric capacitor is in the second discharged state while the second electric capacitor has remained in the charged state, f. communicating to the RFID reader that an activation event of the RFID tag has occurred.
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Specification