CN102750571B - RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device - Google Patents
RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device Download PDFInfo
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- CN102750571B CN102750571B CN201210179913.5A CN201210179913A CN102750571B CN 102750571 B CN102750571 B CN 102750571B CN 201210179913 A CN201210179913 A CN 201210179913A CN 102750571 B CN102750571 B CN 102750571B
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Abstract
The present invention provides RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device, force sensitive device forms parallel-connection structure with the antenna of RFID label tag, the circuit that force sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection is with the part that the logic circuit controlling break-make is chip: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, the first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, now Antenna Operation is under the second resonant frequency；The instruction that RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.The present invention can detect the change of pressure at lower cost.
Description
Technical field
The present invention relates to RFID(RadioFrequencyIdentification, RF identification) technical field, particularly relate to RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device.
Background technology
In recent years, rfid system had become more prevalent.Rfid system is mainly used in the identification to people and thing.In general, this system includes at least a RFID reader, and this RFID reader can be launched in the range of a setting and accept the radiofrequency signal from one or more RFID label tag.This RFID label tag is usually encapsulated, and can paste on one object, and it includes that one can carry out the microchip of communication for information with antenna.This microchip is an integrated circuit in general, and it can be used to store and process information, modulation /demodulation radiofrequency signal, and can run other specific function.The antenna of RFID label tag is used to receive and send radiofrequency signal, and is commonly available to a kind of special frequency.
In some equipment, when the stress having been used for monitoring product local environment with the rfid system of force sensitive device has exceeded acceptable stress.In general these equipment requirements induction installations to have a lasting energy source, is used for detecting the change of pressure, but this can increase the cost of equipment.It addition, some equipment requirements induction installations to be also connected with a comparator circuit, thus detecting the degree size of deviation reference voltage, this requirement considerably increases the cost of equipment.In a word, improving what rfid system was a need for, it requires to can be used to detect the change of pressure when not using lasting energy source or using the adjunct circuit of a kind of low cost.
Summary of the invention
The embodiment of the present invention provides RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device, detects the change of pressure at lower cost.
On the one hand, embodiments provide the RFID label tag of a kind of band force sensitive device, the chip of described RFID label tag has two pins；Described force sensitive device is connected with the two pin, and form parallel-connection structure with the antenna of described RFID label tag, the change of extraneous stress can cause the change of the resistance of force sensitive device own, the circuit that described force sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines force sensitive device with sky line parallel: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is monopole antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is double-doublet antenna: described force sensitive device forms parallel-connection structure with a wherein antenna；Or described force sensitive device and two antennas concurrently form parallel-connection structure.
Optionally, in an embodiment of the present invention, described force sensitive device is resistor-type force sensitive device, and described force sensitive device includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor.
On the other hand, embodiments provide the RFID label tag of a kind of band force sensitive device, the chip of described RFID label tag has a pin；One end of described force sensitive device is connected with this pin, the other end is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of extraneous stress can cause the change of the resistance of force sensitive device own, the circuit that described force sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines force sensitive device with sky line parallel: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is monopole antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is double-doublet antenna: described force sensitive device forms parallel-connection structure with a wherein antenna；Or described force sensitive device and two antennas concurrently form parallel-connection structure.
Optionally, in an embodiment of the present invention, described force sensitive device is resistor-type force sensitive device, and described resistor-type force sensitive device includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor.
Another aspect, embodiments provide the RFID label tag of a kind of band force sensitive device, described force sensitive device is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of extraneous stress can cause the change of the resistance of force sensitive device own, the circuit that described force sensitive device is connected with antenna has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines force sensitive device with sky line parallel: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is monopole antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is double-doublet antenna: described force sensitive device forms parallel-connection structure with a wherein antenna；Or described force sensitive device and two antennas concurrently form parallel-connection structure.
Optionally, in an embodiment of the present invention, described force sensitive device is resistor-type force sensitive device, and described resistor-type force sensitive device includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor.
Another further aspect, embodiments provides the rfid system of a kind of band force sensitive device, and described rfid system includes that RFID label tag and RFID reader, described RFID label tag include the RFID label tag of above-mentioned band force sensitive device；Described RFID reader sends the instruction break-make with the logic circuit of control RFID label tag, thus by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
Another further aspect, embodiments provide the stress detection method of the rfid system of a kind of band force sensitive device, described stress detection method is applied to the rfid system of above-mentioned band force sensitive device, including: send instruction to control the break-make of the logic circuit of RFID label tag by described RFID reader；The break-make with control logic circuit is instructed: when logic circuit disconnects by what RFID tag RFID reader sent, force sensitive device not with sky line parallel, now be placed on certain by force intensity under, the first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, be now placed on certain by force intensity under, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；Described RFID reader is utilized to compare from the difference between the signal intensity of the different frequency of antenna to detect the change of pressure.
Technique scheme has the advantages that because using force sensitive device to form parallel-connection structure with the antenna of RFID label tag, the circuit that force sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection is with the part that the logic circuit controlling break-make is chip: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, the first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, now Antenna Operation is under the second resonant frequency；The instruction that RFID tag RFID reader sends is with the break-make of control logic circuit, thus realize by the technological means comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna, so having reached the technique effect of the change detecting pressure at lower cost, and utilize the energy that RFID obtains, solve the powerup issue of stress detection.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, the accompanying drawing used required in embodiment or description of the prior art will be briefly described below, apparently, accompanying drawing in describing below is only some embodiments of the present invention, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the schematic diagram that embodiment of the present invention force sensitive device is connected with RFID label chip；
Fig. 2 is the equivalent circuit diagram of RFID label chip inside antenna；
Fig. 3 is the schematic diagram that embodiment of the present invention force sensitive device, logic switch are connected with RFID label chip inside antenna equivalent circuit；
Fig. 4 is that embodiment of the present invention force sensitive device is joined directly together, with RFID label antenna, the schematic diagram connect；
Fig. 5. for the structure explanatory diagram of embodiment of the present invention force sensitive device；
Fig. 6 is the flow chart of embodiment of the present invention stressing conditions based on signal intensity detection method.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments.Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art are obtained under not making creative work premise, broadly fall into the scope of protection of the invention.
The force sensitive device of the embodiment of the present invention is connected with the chip of RFID label tag and at least there are three kinds of situations:
Two pins structure:
The embodiment of the present invention is device, system and the technology of a kind of change for detecting pressure.This system contains a RFID label tag, and the chip of this RFID label tag has two pins.Force sensitive device is connected with the two pin, forms parallel-connection structure with antenna.The change of extraneous stress can cause the change of the resistance of force sensitive device own.The circuit that pin is connected with chip has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip.The break-make of logic circuit determine force sensitive device whether with sky line parallel.
When logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, the first resonant frequency of antenna and signal intensity keep constant.When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency.RFID reader can send the break-make of instruction control logic circuit to label, when logic circuit is connected, and can be by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
For an example, this system contains a RFID label tag, an only antenna on this label.Two pins are had on the chip of this label.Force sensitive device is connected with the two pin, forms parallel-connection structure with this root antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of extraneous stress can cause the change of the resistance of force sensitive device own.
After being placed on certain stressing conditions lower a period of time when logic circuit is connected, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency.RFID reader can send instruction to label, and can be detected the change of pressure by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.Or rather, force sensitive device should have relatively low resistance, and its instantiation includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
For another example, this system contains a RFID label tag, and this label has two antennas.Now there are two kinds of situations.The first situation is that force sensitive device is connected with the two pin, forms parallel-connection structure with first antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of extraneous stress can cause the change of the resistance of force sensitive device own.And second antenna is all the time with the first resonant frequency proper communication.
When logic circuit is connected, after being placed on certain stressing conditions lower a period of time, at least meeting of the characteristic frequency of first antenna and signal intensity changes, and it is operated under the second resonant frequency.RFID reader can send instruction to label, and can detect the change of pressure by difference between the signal intensity of the different frequency of first and second antennas during CL Compare Logic circuit ON.The change of pressure can also be detected by the difference between the signal intensity of the different frequency during logic circuit break-make that compares second antenna self.
The second situation is, force sensitive device is connected with the two pin, concurrently forms parallel-connection structure with two antennas.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of extraneous stress can cause the change of the resistance of force sensitive device own.This situation only containing an antenna with label is similar.
After being placed on certain stressing conditions lower a period of time when logic circuit is connected, antenna features frequency and signal intensity at least have one and change, and it is operated under the second resonant frequency.RFID reader can send instruction to label, and can be detected the change of pressure by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.The first situation circuit connects fairly simple, and during work, the resonant frequency of two antennas may be different, can affect the precision of measurement.The second situation circuit connects more complicated, but during work, the resonant frequency of two antennas is consistent, and certainty of measurement is higher.Or rather, force sensitive device should have relatively low resistance, and its instantiation includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
One pin configuration:
The chip of this label can only have a pin, and this pin outwards one end with force sensitive device is connected, and the other end of force sensitive device is attached directly on antenna.Pin is similar at the junction point of chip internal and the situation of two pins, finally remains and to reach and the purpose of sky line parallel.On the circuit that pin is connected, there is a logic circuit controlling break-make with chip internal circuits simultaneously.
When logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, the first resonant frequency of antenna and signal intensity keep constant.When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, antenna features frequency and signal intensity at least have one and change, and it is operated under the second resonant frequency.RFID reader can send the break-make of instruction control logic circuit to label, when logic circuit is connected, and can be by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
For an example, this system contains a RFID label tag, an only antenna on this label.A pin is had on the chip of this label.Force sensitive device is connected with this pin, and the force sensitive device other end is attached directly on antenna, forms parallel-connection structure with antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of extraneous stress can cause the change of the resistance of force sensitive device own.
After being placed on certain stressing conditions lower a period of time when logic circuit is connected, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal intensity at least have one and change.RFID reader can send instruction to label, and can be detected the change of pressure by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.Or rather, force sensitive device should have relatively low resistance, and its instantiation includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
For another example, this system contains a RFID label tag, and this label has two antennas.A pin is had on the chip of this label.Force sensitive device is connected with this pin, and the force sensitive device other end is attached directly on antenna, forms parallel-connection structure with first antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of extraneous stress can cause the change of the resistance of force sensitive device own.And second antenna is all the time with the first resonant frequency communication.
When logic circuit is connected, after being placed on certain stressing conditions lower a period of time, first Antenna Operation is under the second resonant frequency, and at least meeting of its characteristic frequency and signal intensity changes.RFID reader can send instruction to label, and can detect the change of pressure by difference between the signal intensity of the different frequency of first and second antennas during CL Compare Logic circuit ON.The change of pressure can also be detected by the difference between the signal intensity of the different frequency during logic circuit break-make that compares first antenna self.Or rather, force sensitive device should have relatively low resistance, and its instantiation includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
Without pin configuration:
When not having pin on the chip of RFID label tag, force sensitive device can be attached directly on antenna.In this case, the antenna being connected with force sensitive device can not depart from force sensitive device and with normal frequency for communication.After being placed on certain stressing conditions lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change.RFID reader can send instruction to label apparatus, by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
For an example, this system contains a RFID label tag, and this label has two antennas.Force sensitive device is directly connected with first antenna, and second antenna is not connected with force sensitive device all the time with the first resonant frequency proper communication.After being placed on certain stressing conditions lower a period of time, first Antenna Operation is under the second resonant frequency, and at least meeting of its characteristic frequency and signal intensity changes, and the characteristic frequency of second antenna and signal intensity are constant.RFID reader can send instruction to label, and can detect the change of pressure by comparing the difference between the signal intensity of the different frequency of first and second antennas.Or rather, force sensitive device should have relatively low resistance, and its instantiation includes: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
In the same way, the chip of antenna can also can carry one can also carry multiple pin without pin by band.The radical of antenna can be one, two the most.Can also connect one or more force sensitive device accordingly, the model of force sensitive device can be the same or different simultaneously.For a kind of instantiation of device, after being placed on certain stressing conditions lower a period of time, at least meeting of the characteristic frequency of the antenna being connected with force sensitive device and signal intensity changes.RFID reader can send instruction to label apparatus, by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
For the instantiation of a kind of force sensitive device, simultaneous compares the method for numerical value and includes that these compare numerical value compares with most signal strength values.These signal strength values belong to different frequencies, and are associated with most stress values, are simultaneously based on comparison mentioned above and can detect the level of stress.
But, for another aspect, a rfid system includes a RFID label tag device and a RFID reader device.This RFID label tag device is used to send two kinds of signals, and signal when signal when the most above-mentioned logic circuit disconnects is connected with logic circuit, the request being subject to is responded by a kind of meeting of both signals.RFID reader device is used at least sending RFID label tag device one request.Install reading device be in order to accept from the logic circuit of label connect time signal strength values and logic circuit disconnect time signal strength values between fiducial value, and these fiducial values are converted into the varying level of stress.
In an example, the antenna of RFID label tag is connected with force sensitive device, has a logic circuit controlling break-make on this connection line.In the case of logic circuit break-make whether two kinds, have corresponding two kinds of different frequencies from antenna.After logic circuit is connected and this label apparatus is positioned over certain stressing conditions lower a period of time, due to the change of resonant frequency, the intensity level of two kinds of signals will be produced.
In an example, RFID label tag device includes first, second two antennas.Preferably, first antenna is connected with force sensitive device, after this label apparatus is placed on certain stressing conditions lower a period of time, due to the change of resonant frequency, will produce the different of secondary signal intensity level and the first signal strength values.
Another further aspect, embodiments provides the rfid system of a kind of band force sensitive device, and described rfid system includes that RFID label tag and RFID reader, described RFID label tag include the RFID label tag of above-mentioned band force sensitive device；Described RFID reader sends the instruction break-make with the logic circuit of control RFID label tag, thus by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
Another further aspect, embodiments provide the stress detection method of the rfid system of a kind of band force sensitive device, described stress detection method is applied to the rfid system of above-mentioned band force sensitive device, including: send instruction to control the break-make of the logic circuit of RFID label tag by described RFID reader；The break-make with control logic circuit is instructed: when logic circuit disconnects by what RFID tag RFID reader sent, force sensitive device not with sky line parallel, now be placed on certain by force intensity under, the first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, be now placed on certain by force intensity under, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；Described RFID reader is utilized to compare from the difference between the signal intensity of the different frequency of antenna to detect the change of pressure.
As it is shown in figure 1, the schematic diagram of the force sensitive label 10 being connected with RFID label chip for embodiment of the present invention force sensitive device.In Fig. 1, label apparatus 10, including a base 15, a surface-mounted integrated circuit 13,16,17 and one double-doublet antennas 11,12 of two pins.Having two pins 16,17 on surface-mounted integrated circuit 13, the two pin is outwards connected with force sensitive device 14, and the two pin is in parallel with the equivalent circuit of antenna at chip internal, and has a logic circuit controlling break-make on the circuit connected.Can control whether force sensitive module is access in chip circuit by the break-make of logic circuit, such that it is able to affect the frequency of the antenna being connected with radio-frequency module.When logic circuit disconnects, label antenna is with the first resonant frequency communication.When logic circuit is connected, after being placed on certain stressing conditions lower a period of time, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal intensity at least have one and change.
In an example, transmitting terminal 11,12 are made up of one or more different low electrical resistant materials, these materials have higher electric conductivity, such as copper, silver, and aluminum, they and force sensitive device mentioned above are by two pins 16,17 and antenna 11,12 be connected, when antenna 11, after 12 are placed on certain stressing conditions lower a period of time, force sensitive device can cause the change of one or more transmitting terminal generation resonant frequency.The frequency of this change is the most different with the frequency of reception and transmission.Such as, after force sensitive device is positioned over certain stressing conditions lower a period of time, may result in transmission frequency and accept in frequency that at least one changes.
In another example, the antenna frequencies value set at the beginning will be above the antenna frequencies under certain force environment, and then when reaching certain stress, it will reduce.In another example, the antenna frequencies set at the beginning is less than the antenna frequencies under certain stressing conditions, and when reaching certain stressing conditions, it will rise.The such force sensitive device that can be used for the present invention has: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
Type based on force sensitive device is different, causes the stressing conditions of change to be probably a specific stress value and is also likely to be the scope of a selectively stress value.The length of time necessarily causes the change of antenna resonance frequency, and antenna quality also results in different changes.Such as, on antenna with the type of force sensitive device can affect and change the length of antenna resonance frequency required time.
As in figure 2 it is shown, be the equivalent circuit diagram of RFID label antenna.In tag coil antenna enters the alternating magnetic field that read write line produces, the interaction between label antenna and reading and writing device antenna is similar to transformator.Both coils are equivalent to primary coil and the secondary coil of transformator.The resonant tank formed by label antenna is as in figure 2 it is shown, include the coil inductance (L) of label antenna, parasitic capacitance (Cp) and shunt capacitance (C2), its resonant frequency isIn formula, C is CpAnd C2Parallel equivalent electric capacity, R1, R2For circuit internal inductance coil and the equivalent resistance of other devices.The carrier frequency that label and read write line two-way communication use is exactly f.When requiring that tag antenna coil profile is the least, i.e. area is little, and need certain operating distance, the aerial coil mutual induction amount that RFID label tag and read write line are asked the most substantially can not meet actual demand, the Ferrite Material with high permeability can be inserted inside tag antenna coil, to increase mutual induction amount, thus the problem that bucking coil cross section is little.
As it is shown on figure 3, for embodiment of the present invention force sensitive device, control the schematic diagram that the logic circuit of break-make is connected with RFID label antenna equivalent circuit.The resonant tank formed by label antenna is as it can be seen, include the coil inductance (L) of label antenna, parasitic capacitance (Cp) and shunt capacitance (C2), its resonant frequency isFormula C is CpAnd C2Parallel equivalent electric capacity, R1, R2For circuit internal inductance coil and the equivalent resistance of other devices.M is the variable resistance representing force sensitive device, and S is the logic circuit controlling break-make.When logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, the first resonant frequency of antenna and signal intensity keep constant.When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal intensity at least have one and change.
As shown in Figure 4, the sketch of the passive RFID tags device 40 of the change of pressure can be detected for the embodiment of the present invention.As shown in Figure 4, label apparatus 40 includes a base 45, an integrated circuit 43 and a double-doublet antenna 41,42.The force sensitive device 44 being connected with antenna 42 will affect the resistance of antenna 42.The material that force sensitive device 44 is suitable for can be according to antenna 41, and the current voltage of any in 42 controls any one frequency both pinpointed.For an example, antenna 41,42 is installed it can be made to produce resonance in identical frequency.For another example, antenna 41,42 is installed it can be made to produce resonance in different frequencies.
In an example, transmitting terminal double-doublet antenna 41,42 is made up of one or more different low electrical resistant materials, and these materials have higher electric conductivity, such as copper, silver, and aluminum, they are connected with force sensitive device mentioned above, when antenna 41, after 42 are placed on certain stressing conditions lower a period of time, force sensitive device can cause the change of one or more transmitting terminal generation resonant frequency, thus causes a different frequency.The change of this frequency is the most different with the frequency received and send.Such as, after force sensitive device is positioned over certain stressing conditions lower a period of time, may result in transmission frequency and accept in frequency that at least one changes.
In another example, the antenna frequencies value set at the beginning will be above the antenna frequencies under certain force environment, and then when reaching certain stress, it will reduce.In another example, the antenna frequencies set at the beginning is less than the antenna frequencies under certain stressing conditions, and when reaching certain stressing conditions, it will rise.Such force sensitive device of the invention that can be used for this has: strain-type force sensitive device, condenser type force sensitive device, condenser type loading sensor, differential capacitance pressure sensitive device, differential capacitance formula acceleration sensitive device, ADXL50 condenser type integrated acceleration sensitive device, pressure-sensing conductive rubber sensor etc..
Type based on force sensitive device is different, causes the stressing conditions of change to be probably a specific stress value and is also likely to be the scope of a selectively stress value.The length of time necessarily causes the change of antenna resonance frequency, and antenna quality also results in different changes.Such as, on antenna with the type of force sensitive device can affect and change the length of antenna resonance frequency required time.
As it is shown in figure 5, force sensitive device example includes electrode 51,52, pressure-sensing conductive rubber 53, dielectric film 54 and stress F.Pressure-sensing conductive rubber is a kind of to pressure-sensitive elastomeric material.Its feature is that the resistance value of elastomeric material changes with the change of pressure, and therefore it still has the pressure element of switching function.When be under pressure F time, pressure-sensing conductive rubber 53 make two electrodes 51,52 formed paths, when stress F disappear after, two electrodes 51, between 52 stop increase.
As shown in Figure 6, for the embodiment of the present invention by using the label apparatus of multiple antennas to detect a kind of method flow diagram that stress changes.Need it is contemplated that, device mentioned above uses a label integrated circuit to carry out and the exchanging of multiple antennas.
As shown in Figure 6,50, RFID reader sends energy and instruction to label apparatus.52, logic circuit is in the state of disconnection at initial time, and the label apparatus antenna not being connected with force sensitive device receives energy and instruction.54, the electromagnetic wave carrying energy is converted into a DC(direct current by label apparatus) voltage, thus label just can be made to perform the requirement of instruction.And this conversion needs to use an electric charge pump, a rectification circuit, or be connected with each other, or to use other energy conversion device.56, label apparatus sends signal by the sky alignment reader not being connected with force sensitive device.58, the energy intensity receiving signal is measured and recorded to reader.60, reader sends the instruction connecting logic circuit to label apparatus.62, the label apparatus antenna being connected with force sensitive device sends data.64, reader measurement receives the energy intensity of signal.66, reader calculated goes out the fiducial value of a reaction signal intensity.68, fiducial value is changed into different stress values by reader.For an example, reader can set a time period for receiving the signal of label, and without receiving signal, signal intensity will be recorded as 0 by reader.
In this system, reader will compare from the signal strength values of the antenna not being connected with force sensitive device as a reference value, the signal strength values of the label antenna that it is connected with force sensitive device.By the signal from the transmitting terminal being connected with force sensitive device and be not connected with force sensitive device received, reader can collect the fiducial value representing unlike signal intensity.Then, RFID reader can be converted into the stressing conditions residing for label such a fiducial value.For a concrete example, configuring this RFID reader is in order to the difference from connection or the RF signal intensity of the antenna being not connected to force sensitive device received is converted into stress value by the reference data stored by use.
Best situation is, using be not connected to force sensitive device antenna as a reference, the change caused due to the coupling between label and reader can be filtered out.Additionally, as previously mentioned, the time length that force sensitive device is applied in design to make the change of its resistance value and label be placed under specific stress forms relation one to one.Such as, force sensitive device is only positioned on an antenna, the signal from RFID label tag device so can be allowed to change within the specific limits as a kind of function, and the function that this function antenna just just has after being placed on the time under certain stress.Ibid, the application of the invention, under conditions of RFID label tag is passive, RFID reader be able to detect that label apparatus be placed under certain stress and this stress the most within the acceptable range.
The various RFID label tag not using two antennas also can perceive the change of stress with force sensitive device, and the change of perception stress is also to be able to recognize antenna based on the change of resonant frequency on antenna to receive the change of signal.
Such as by the design to the antenna being connected with force sensitive device, the frequency of antenna can be made at ISM(IndustrialScientificMedical, industry, science, medical science) the interior change of frequency range, the label of standard can connect this antenna being connected with force sensitive device and logic circuit.
Such as in a concrete example, label antenna can so set, before being exposed in certain force environment, the resonant frequency of antenna is 902-928MHZ, but label is once exposed in certain force environment, impact due to stress, the resonant frequency of antenna just reduces to 899.5-927.5MHZ, frequency bins (902-928MHZ) at U.S. RFID is divided into 52 channels, the channel that can not receive of skipping that reader can be random in these 52 channels goes, the benefit of this jump of reader is exactly can effectively to prevent multiple reader from attempting the conflict using same frequency to be caused in same physical space.
The most in one example, RFID frequency range (902-928MHZ) is not divided into 52 channels but has been divided equally into the antenna settings of n channel tag and has been operated under this frequency range (902-928MHZ).Owing to label antenna is connected with force sensitive device, as long as so stress has exceeded the scope of value set in advance, the operating frequency of antenna tag antenna drops down among (899.5-927.5MHZ) this frequency range.Therefore just being got rid of from band limits by channel n compared with original frequency range and go, therefore the frequency range (899.5-927.5MHZ) after change just no longer allows label to carry out exchanging of information with channel n.
In concrete example, if the environment at label place has exceeded intended field of load, reader can only send instruction by channel 1 to n-1 to label, label also can be made a response, because the antenna in label just can only be at this frequency ranges of operation, when reader sends instruction with the frequency of n channel to label, because the change of label stress already leads to the resonant frequency of label antenna and has descended to 899.5-927.5MHZ and no longer reach 928MHZ so label is the most no longer made a response, transmit information back to reader.
Favourable aspect is that the change of the operating frequency of antenna caused beyond value set in advance due to stress is just reflected by the disappearance of this communication for information.
In a model, reader can send an instruction between channel n-1 and channel n to label and further confirm that the operating frequency range of label antenna has occurred that drift, because label can receive the instruction sent by channel n-1, and can pass through channel n-1 can be to reader feedback information, because label can not receive the instruction sent by channel n, and can not pass through channel n can be to reader feedback information, and the operating frequency range thus determining label antenna has occurred that drift.
The change of stress causes the operating frequency of label antenna to occur drift up and down and current invention to be not limited in and frequency range is averagely divided into n channel.
The embodiment of the present invention can detect the change of pressure at lower cost, and utilizes the energy that RFID obtains, and solves the powerup issue of stress detection.
The enforcement of each feature of this system may relate to software, hardware is likely to relate to the combination of software and hardware and can be only achieved, and the enforcement of many advantages of such as system is to realize by the way of programming a kind of high-caliber process and OO programming language and computer and other equipment machines mutual exchanges.Each such function program may be stored in a storage intermediary to be read by a computer and processor in such as read only memory and realize above-mentioned function.
Those skilled in the art are it will also be appreciated that the various illustrative components, blocks (illustrativelogicalblock) listed of the embodiment of the present invention, unit, and step can pass through electronic hardware, computer software, or both combinations realize.For clearly showing that the replaceability (interchangeability) of hardware and software, above-mentioned various illustrative components (illustrativecomponents), unit and step the most universally describe their function.Such function is to realize depending on specifically applying the design requirement with whole system by hardware or software.Those skilled in the art can be for every kind of specific application, it is possible to use the function described in the realization of various methods, but this realization is understood not to the scope beyond embodiment of the present invention protection.
Various illustrative logical block described in the embodiment of the present invention, or unit can pass through general processor, digital signal processor, special IC (ASIC), field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the design of any of the above described combination realize or operate described function.General processor can be microprocessor, and alternatively, this general processor can also be any traditional processor, controller, microcontroller or state machine.Processor can also realize by calculating the combination of device, such as digital signal processor and microprocessor, multi-microprocessor, one or more microprocessors one Digital Signal Processor Core of associating, or any other like configuration realizes.
Method or the step of algorithm described in the embodiment of the present invention can be directly embedded into hardware, the software module of processor execution or the combination of both.Software module can be stored in RAM memory, flash memory, ROM memory, eprom memory, eeprom memory, depositor, hard disk, moveable magnetic disc, CD-ROM or this area in other any form of storage medium.Exemplarily, storage medium can be connected with processor, so that processor can read information from storage medium, it is possible to deposit write information to storage medium.Alternatively, storage medium can also be integrated in processor.Processor and storage medium can be arranged in ASIC, and ASIC can be arranged in user terminal.Alternatively, processor and storage medium can also be arranged in the different parts in user terminal.
In one or more exemplary designs, the above-mentioned functions described by the embodiment of the present invention can realize in the combination in any of hardware, software, firmware or this three.If realized in software, these functions can store with on the medium of computer-readable, or is transmitted on the medium of computer-readable with one or more instructions or code form.Computer readable medium includes computer storage medium and is easy to so that allowing computer program transfer to the telecommunication media in other place from a place.Storage medium can be that any general or special computer can be with the useable medium of access.Such as, such computer readable media can include but not limited to RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage device, or other any may be used for carrying or storage with instruction or data structure and other can be read the medium of program code of form by general or special computer or general or special processor.In addition, any connection can be properly termed computer readable medium, such as, if software is by coaxial cable, optical fiber computer, twisted-pair feeder, Digital Subscriber Line (DSL) or being also contained in defined computer readable medium with wireless way for transmittings such as the most infrared, wireless and microwaves from a web-site, server or other remote resource.Described video disc (disk) and disk (disc) include Zip disk, radium-shine dish, CD, DVD, floppy disk and Blu-ray Disc, and disk is generally with magnetic duplication data, and video disc generally carries out optical reproduction data with laser.Combinations of the above can also be included in computer readable medium.
Above-described detailed description of the invention; the purpose of the present invention, technical scheme and beneficial effect are further described; it is it should be understood that; the foregoing is only the detailed description of the invention of the present invention; the protection domain being not intended to limit the present invention; all within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. done, should be included within the scope of the present invention.
Claims (8)
1. the RFID label tag of a band force sensitive device, it is characterised in that have two pins on the chip of described RFID label tag；Described force sensitive device is connected with the two pin, and form parallel-connection structure with the antenna of described RFID label tag, the change of extraneous stress can cause the change of the resistance of force sensitive device own, the circuit that described force sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines force sensitive device with sky line parallel: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna；
Wherein, the antenna of described RFID label tag is double-doublet antenna；
Described force sensitive device is pressure-sensing conductive rubber sensor, described pressure-sensing conductive rubber sensor includes the first electrode, the second electrode, pressure-sensing conductive rubber and dielectric film, described pressure-sensing conductive rubber sensor is the pressure element with switching function, when being under pressure, pressure-sensing conductive rubber makes the first electrode and the second electrode form path, after pressure disappears, between the first electrode and the second electrode, resistance increases；
When the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, transformator is formed between antenna and the antenna of RFID reader of described RFID label tag, with thinking that force sensitive device provides energy source, the antenna of RFID label tag and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, the electromagnetic wave that the antenna of RFID label tag receives is converted to DC voltage by the most interconnective electric charge pump and rectification circuit by described force sensitive device, with thinking that described RFID label tag performs the instruction offer energy source that described RFID reader sends.
2. the RFID label tag of band force sensitive device as claimed in claim 1, it is characterised in that when the antenna of described RFID label tag is double-doublet antenna: described force sensitive device forms parallel-connection structure with a wherein antenna；Or described force sensitive device and two antennas concurrently form parallel-connection structure.
3. the RFID label tag of a band force sensitive device, it is characterised in that have a pin on the chip of described RFID label tag；One end of described force sensitive device is connected with this pin, the other end is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of extraneous stress can cause the change of the resistance of force sensitive device own, the circuit that described force sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines force sensitive device with sky line parallel: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna；
Wherein, the antenna of described RFID label tag is double-doublet antenna；
Described force sensitive device is pressure-sensing conductive rubber sensor, described pressure-sensing conductive rubber sensor includes the first electrode, the second electrode, pressure-sensing conductive rubber and dielectric film, described pressure-sensing conductive rubber sensor is the pressure element with switching function, when being under pressure, pressure-sensing conductive rubber makes the first electrode and the second electrode form path, after pressure disappears, between the first electrode and the second electrode, resistance increases；
When the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, transformator is formed between antenna and the antenna of RFID reader of described RFID label tag, with thinking that force sensitive device provides energy source, the antenna of RFID label tag and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, the electromagnetic wave that the antenna of RFID label tag receives is converted to DC voltage by the most interconnective electric charge pump and rectification circuit by described force sensitive device, with thinking that described RFID label tag performs the instruction offer energy source that described RFID reader sends.
4. the RFID label tag of band force sensitive device as claimed in claim 3, it is characterised in that when the antenna of described RFID label tag is double-doublet antenna: described force sensitive device forms parallel-connection structure with a wherein antenna；Or described force sensitive device and two antennas concurrently form parallel-connection structure.
5. the RFID label tag of a band force sensitive device, it is characterized in that, described force sensitive device is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of extraneous stress can cause the change of the resistance of force sensitive device own, the circuit that described force sensitive device is connected with antenna has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines force sensitive device with sky line parallel: when logic circuit disconnects, force sensitive device not with sky line parallel, if sensor is under pressure, first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, if sensor is under pressure, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna；
Wherein, the antenna of described RFID label tag is double-doublet antenna；
Described force sensitive device is pressure-sensing conductive rubber sensor, described pressure-sensing conductive rubber sensor includes the first electrode, the second electrode, pressure-sensing conductive rubber and dielectric film, described pressure-sensing conductive rubber sensor is the pressure element with switching function, when being under pressure, pressure-sensing conductive rubber makes the first electrode and the second electrode form path, after pressure disappears, between the first electrode and the second electrode, resistance increases；
When the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, transformator is formed between antenna and the antenna of RFID reader of described RFID label tag, with thinking that force sensitive device provides energy source, the antenna of RFID label tag and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, the electromagnetic wave that the antenna of RFID label tag receives is converted to DC voltage by the most interconnective electric charge pump and rectification circuit by described force sensitive device, with thinking that described RFID label tag performs the instruction offer energy source that described RFID reader sends.
6. the RFID label tag of band force sensitive device as claimed in claim 5, it is characterised in that when the antenna of described RFID label tag is double-doublet antenna: described force sensitive device forms parallel-connection structure with a wherein antenna；Or described force sensitive device and two antennas concurrently form parallel-connection structure.
7. a rfid system for band force sensitive device, described rfid system includes RFID label tag and RFID reader, it is characterised in that
Described RFID label tag includes the RFID label tag of band force sensitive device according to any one of claim 1-2, or the RFID label tag of band force sensitive device according to any one of claim 3-4, or the RFID label tag of band force sensitive device according to any one of claim 5-6；
Described RFID reader sends the instruction break-make with the logic circuit of control RFID label tag, thus by comparing the change detecting pressure from the difference between the signal intensity of the different frequency of antenna.
8. the stress detection method of the rfid system of a band force sensitive device, it is characterised in that described stress detection method is applied to the rfid system of band force sensitive device described in claim 7, including:
Instruction is sent to control the break-make of the logic circuit of RFID label tag by described RFID reader；
The break-make with control logic circuit is instructed: when logic circuit disconnects by what RFID tag RFID reader sent, force sensitive device not with sky line parallel, now be placed on certain by force intensity under, the first resonant frequency of antenna and signal intensity keep constant；When logic circuit is connected, force sensitive device and sky line parallel, be now placed on certain by force intensity under, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency；
Described RFID reader is utilized to compare from the difference between the signal intensity of the different frequency of antenna to detect the change of pressure.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210179913.5A CN102750571B (en) | 2012-06-01 | 2012-06-01 | RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device |
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| CN201210179913.5A CN102750571B (en) | 2012-06-01 | 2012-06-01 | RFID label tag, rfid system and the stress detection method of a kind of band force sensitive device |
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| CN102750571B true CN102750571B (en) | 2016-08-03 |
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