• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The radio-tag comprises: a reflector made of electrically conductive material; and an actuator made of a transducer material capable of transforming a variation of energy into a mechanical displacement of the reflector between distant and close positions when the variation of energy crosses. a predetermined threshold for indicating to a reader this event, the transducer material being selected from a group consisting of a thermal shape memory material, a magnetostrictive material and a magnetic shape memory material. The transducer material is also an electrically conductive material. The reflector and the actuator are both formed by the same blade (66) made of this transducer material and a moving part of which moves relative to an antenna between the distant and the close positions when the energy variation crosses the threshold. predetermined.
    公开号:FR3037425A1
    申请号:FR1555450
    申请日:2015-06-15
    公开日:2016-12-16
    发明作者:Bernard Viala；Ramos Juvenal Alarcon
    申请人:Commissariat a lEnergie Atomique CEA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    [0001] 1 RADIO LABEL [1] The invention relates to a radio-tag capable of indicating to a reader, via a wireless link, that a variation of energy has crossed a predetermined threshold. energy being selected from the group consisting of a variation of the temperature of the radio tag and a variation of the magnetic field in which the radio tag is immersed. The invention also relates to an assembly comprising this radio-label and a reader. [2] Radio tags are also known as "RFID (Radio Frequency IDentification) Tags" or "RFID Tag". [3] Known RFID tags include: - an electrically insulating substrate, - an antenna for establishing the wireless connection with the reader, this antenna being entirely deposited and fixed without any degree of freedom on the insulating substrate, - a reflector made of electrically conductive material and electrically isolated from the antenna for reflecting at least a portion of the electromagnetic waves emitted by the antenna, this reflector being movable relative to the antenna between a remote position in which the antenna impedance is equal to a first value and a close position in which the impedance of the antenna is equal to a second value different from the first value, and - an actuator made of a transducer material capable of transforming the variation of energy into a mechanical displacement of the reflector between its distant and close positions when the variation of energy crosses the threshold predetermined to indicate to the reader this event, the transducer material being selected from a group consisting of a thermal shape memory material, a magnetostrictive material and a magnetic shape memory material. [4] For example, such a radio tag is disclosed in the following article: R. Bhattacharyya et al: "RFID Tag Antenna Based Temperature Sensing in the Frequency Domain", RFID, 2011, IEEE Conference On RFID. Subsequently, this article is referred to as Item Al in this description. [5] In item Ai, the reflector is a plate of electrically conductive material and the actuator is made of a thermal shape memory polymer. The plate is fixed on the actuator so as to be moved by this actuator between the remote and close positions. In the remainder of the description, unless otherwise indicated, "shape memory material" means a thermal shape memory material, that is to say a material which deforms abruptly when its temperature crosses a threshold. ST temperature. This temperature threshold is also called the "transition temperature" of the material. For simplicity, here the hysteresis phenomena are neglected so that it is considered that the transition temperature is the same when heating and when cooling the shape memory material. When the temperature is below the threshold ST, the actuator holds the plate in the position remote from the antenna. In the remote position, the plate is 5 to about 1 cm below the antenna. If the temperature of the radio tag exceeds the threshold ST, then the actuator deforms and moves the plate to the close position. In its close position, the plate is about 3 mm below the antenna. The presence or absence of the plate near the antenna changes its impedance. The modification of the impedance of the antenna is detectable by the reader. Thus, the reader can know if the temperature of the radio-tag has exceeded or not the threshold ST. The radio-tag of the article Al has the advantage of operating in exactly the same way regardless of its orientation in space. In particular, the operation of the antenna of the article Al does not depend on its orientation relative to the gravity field. [007] Such radio tags capable of indicating whether a temperature threshold has been exceeded have many applications. For example, they can be used, when they are fixed on a frozen product, to check that the cold chain has been respected and that the temperature of the frozen product and therefore that of the radio-label has never exceeded the threshold ST. Of course, the field of application of such tags is not limited to frozen products. They can be used on any object whose temperature must be monitored at one time or another. [8] In the article Ai, the antenna is simple to manufacture because it is entirely deposited on the insulating substrate. Many manufacturing processes can then be used to manufacture it simply. For example, the antenna can be manufactured by depositing a conductive layer on the substrate and then etching this conductive layer. The antenna can also be made by localized projection on the substrate of a conductive ink. By cons, the realization of the reflector and the actuator seriously complicates the manufacture of this radio-tag. Indeed, to manufacture the radio-label must be assembled in the same housing, a plate and an actuator. [9] From the state of the art is also known from: - S. Caizzone et al. : "Multi-chip RFID Antenna Integrating Shape-Memory Alloys for Detection of Thermal Thresholds", IEEE 2011. - JP2009162700 application of the company HITACHI®. The state of the art above also relates to radio tags able to detect the crossing of a temperature threshold ST. However, in this state of the art, the variation of the impedance of the antenna is obtained by changing its length and not by moving a reflector. Because of this, the antenna can not be fully deposited on a substrate and must have 3 moving parts. It can not therefore be manufactured by manufacturing processes as simple as those used to fabricate the antenna of the article Al. [0011] The invention therefore aims to propose a radio-tag which retains the advantages of radio- Al article label while still being simpler to manufacture. It therefore relates to a radio-tag in which: the transducer material is also an electrically conductive material, and the reflector and the actuator are both formed by a same blade made of this transducer material and a moving part of which moves relative to the antenna between the distant and near positions when the energy change exceeds the predetermined threshold. The radio-tag above retains the manufacturing simplicity of the antenna of the article Al since its antenna is entirely deposited on the substrate and has no moving part. In particular, the antenna can be made by bonding a wire to the substrate, by photolithography and etching or by printing, for example using an ink jet printer. Moreover, in the claimed radio-label, the same blade of electrically conductive transducer material fulfills both the roles of reflector and actuator. This simplifies the manufacture of the claimed antenna since only one piece instead of two is used to perform the same functions. In addition, the problem of attaching a plate of electrically conductive material to a shape memory polymer is eliminated. Thus, the claimed antenna can detect the crossing of a temperature threshold or magnetic field while remaining simple to manufacture. The embodiments of this radio-tag may include one or more of the following features: the blade has a fixed part anchored without any degree of freedom to the substrate; two ends of the antenna are electrically connected to each other either directly via an electric track or via an electric charge to form a closed electrical circuit, and the radio label is devoid of electronic chip electrically connected to this closed electrical circuit; - Both ends of the antenna are electrically connected to each other via a capacitor to form a resonant LC circuit whose resonance frequency is a function of the inductance of the antenna; The transducer material is a thermal shape memory material whose elongation rate is greater than 1% in response to a temperature variation of 10 ° C. around the predetermined threshold; the blade is arranged in such a way that the displacement of its moving part between the distant and near positions is irreversible; - the amplitude of the maximum deflection (Amax) of the moving part of the blade between its distant and near positions is greater than 1 mm; - the radio-label is a passive radio-tag powered solely from the energy of the electromagnetic waves emitted by the reader. These embodiments of the radio-tag have the following additional advantages: The use of a blade whose fixed part is anchored to the substrate further simplifies the manufacture of the radio-tag. The absence of an electronic chip in the radio-tag makes it possible to further simplify its manufacture. - The use of a shape memory material as a transducer material makes it possible to detect a crossing of a temperature threshold. - Use a transducer material whose deformation is irreversible also allows to store the crossing of the predetermined threshold even in the absence of drive. - The fact that the amplitude of the maximum deflection of the antenna between its distant and near positions is at least greater than 1 mm, facilitates the identification of these two positions. The invention also relates to an assembly comprising: the claimed radio-tag able to indicate to a reader, via a wireless link, that a variation of energy has crossed a predetermined threshold, this variation of energy being chosen from the group consisting of a variation of the temperature of the radio-tag and a variation of the magnetic field in which the radio-tag is immersed, this radio-tag comprising: an electrically insulating substrate, an antenna for establishing the wireless connection with the reader, this antenna being entirely deposited and fixed without any degree of freedom on the insulating substrate, a reflector of electrically conductive material and electrically isolated from the antenna for reflecting at least a portion of the electromagnetic waves emitted by the antenna, this reflector being movable relative to the antenna between a remote position in which e the impedance of the antenna is equal to a first value and a close position in which the impedance of the antenna is equal to a second value different from the first value, and - an actuator made of a transducer material suitable for transforming the energy variation into a mechanical displacement of the reflector between its distant and near positions when the energy change crosses the predetermined threshold so that the frequency range for which the rate of electrical energy transfer between the reader and the radio tag is greater than a predetermined limit, varies at the same time from a first range to a second range in response to the crossing of this predetermined threshold by the variation of energy, these first and second frequency ranges n ' having no common frequencies, the transducer material being selected from a group consisting of a thermally shaped memory material that, a magnetostrictive material and a magnetic memory material, and - the reader adapted to emit an electromagnetic wave at an interrogation frequency to read the radio-label, this reader being able to automatically choose the frequency interrogator to be used so that the rate of transfer of electrical energy between the reader and the radio-tag is greater than the predetermined limit, this reader further comprising a pre-recorded table which associates with the first and second frequency ranges indications, respectively, of not crossing and crossing the predetermined threshold, and the reader is able to transmit to an external device the indication which is associated, by the pre-recorded table, with the interrogation frequency automatically chosen and used for interrogate the radio-label. In all above, the crossing of the predetermined threshold is encoded by the frequency of the electromagnetic wave used to communicate with the reader. This means of coding the information that the predetermined threshold has been crossed or not is independent of the distance that separates the reader from the radio tag. The invention will be better understood on reading the description which follows, given solely by way of non-limiting example while referring to the drawings in which: FIG. 1 is a schematic illustration of a set used to detect the crossing of a temperature threshold; FIG. 2 is an illustration in plan view of a first embodiment of a radio-tag of the assembly of FIG. 1; Figures 3 and 4 are vertical sectional illustrations of the radio tag of Figure 2 in two different positions; FIG. 5 is an illustration in plan view of a plate of the radio-tag of FIG. 2; FIG. 6 is a diagrammatic illustration, in plan view, of a second embodiment of a radio-tag for the assembly of FIG. 1; Figures 7 to 11 are diagrammatic illustrations in vertical section, respectively, of third, fourth, fifth, sixth and seventh embodiment of a radio-tag for the whole of Figure 1. [0019] In these figures, the same references are used to designate the same elements. In the remainder of this description, the features and functions well known to those skilled in the art are not described in detail. [0020] FIG. 1 represents a set 2 for detecting the crossing of a predetermined threshold ST by a variation of energy chosen in the group consisting of a temperature variation and a magnetic field variation. In the particular case described here, the assembly 2 is used to detect a temperature variation of an object 4. The object 4 is for example a package, a package, a living being or any other object to which it can be attached. or attach a radio tag. To this end, the assembly 2 comprises: a radio-tag 6 integral with the object 4, a reader 8 of the radio-tag 6, and an apparatus 10 for processing the information read by the The radio tag 6 is fixed, for example, without any degree of freedom, on the object 4. Typically, it is glued on the object 4. It can also be integrated inside. of the object 4 during its manufacture. It is also possible to fix this radio-label on the object 4 by means of a strap or a collar. It is also possible that the radio-label is fixed on the object 4 with a degree of freedom allowing it to move. For example, only one end or edge of the radio tag is attached to the object 4. The radio tag 6 comprises: a substrate 12 having an upwardly facing upper face; completely deposited and fixed without any degree of freedom on this upper face of the substrate 12, and 25 - an electronic chip 16 deposited and fixed without any degree of freedom directly on the substrate 12. [0024] In this embodiment, the upper face is flat and horizontal. The substrate 12 is made of an electrically insulating material. By "electrically insulating material" is meant here a material whose resistivity at 20 ° C. is greater than 106 μm and, preferably, greater than 10 10 μm. In addition, the substrate 12 is made of a material permeable to the electromagnetic waves emitted by the antenna 14. For example, the substrate 12 is a polymer such as polyethylene naphthalene (PEN), polyethylene terephthalate (PET) or plexiglass which the thickness is between 200 μm and 2 mm. The substrate 12 may also be made of other non-magnetic material such as paper or cardboard. In Figure 1, the antenna 14 is shown schematically. Examples of possible embodiments are described in more detail with reference to the following figures. The antenna 14 can receive and emit an electromagnetic wave. In the present case, it is designed to reflect, generally only a part, of an electromagnetic wave emitted by the reader 8. Typically, the antenna 14 is composed of an electric track made of electrically conductive material deposited directly on the upper face of the substrate 12. "Electrically conductive material" means here a material whose resistivity at 20 ° C is less than 10 m, and preferably less than 10-3 or 10-5 0. m. All the antenna 14 is fixed without any degree of freedom on the upper face of the substrate 12. [0026] Many methods are possible for producing the antenna 14 on the upper face of the substrate 12. For example, the antenna 14 is obtained by gluing a conductive wire or by depositing a layer of electrically conductive material on this upper face and then etching this layer. The antenna 14 can also be obtained by localized projection of a conductive ink directly on the upper face of the substrate 12. The electronic chip 16 comprises: a transceiver 18 electrically connected to the antenna 14; an electronic computer 20 adapted to execute instructions stored in a memory for processing and transmitting information, and - a non-volatile memory 22 including, for example, the instructions executed by the computer 20 and data such as a unique identifier 24 The identifier 24 makes it possible to uniquely identify this radio-label 6 among all the other radio-tags that can be read by reader 8. The transceiver 18 transforms at the same time. at least a part of the electromagnetic wave picked up by the antenna 14 in electrical energy stored, for example, in a capacitor 26. The capacitor 26 is integrated inside the chip 1 6. The electrical energy stored in this capacitor 26 is then used, when it exceeds a predetermined threshold, to power the computer 20.
    [0002] The transceiver 18 also demodulates the received electromagnetic wave to transform the data encoded in this electromagnetic wave into digital data transmitted to the computer 20. The modulation of the data transmitted to the radio-tag 6 is, for example, a modulation of amplitude. or phase modulation. Finally, the transceiver 18 is also capable of transmitting to the reader 8 30 data that are transmitted to it in digital form by the computer 20. For example, for this, the transceiver 18 modifies the impedance input of the chip 16 according to the information bits to be transmitted. The modification of the input impedance of the chip 16 results in a modification of the reflection coefficient of the antenna 14. The value of the input impedance of the chip 16 is, for example, modified by modifying the value of a resistive load connected between terminals of the antenna 14. Thus, depending on the value of the bit or the group of bits to be transmitted, the amplitude of the electromagnetic wave reflected by the antenna 14 is modified. This modification of the ratio between the amplitude of the electromagnetic wave emitted by the reader 8 and the amplitude of the electromagnetic wave reflected by the antenna 14 is detected by the reader 8. From this difference in amplitudes, the reader extracts 3037425 8 the value of the bit or the group of bits transmitted by the radio-tag. Typically, the part of the electromagnetic wave that is not reflected by the antenna 14 is used by the transceiver 18 to charge the capacitor 26. This communication protocol between the radio-tag 6 and the reader 8 is known as "retro-modulation" or "backscattering" in English. It allows the reader 8: - to communicate with the radio-tag 6 via a wireless link 30, and at the same time - to feed the radio-tag 6. With this protocol, the Link 30 may be established with a radio tag 10 located at a distance d from the reader. Typically, this distance d is greater than 2 cm, 10 cm, 1 m or 10 m. Generally, this distance d is also less than 50 m or 30 m. The frequency fr of the electromagnetic wave used to establish the link 30 is often chosen from the group consisting of the following frequencies: 15 - the range of frequencies between 860 MHz and 960 MHz for the UHF radio tags (Ultra High Frequency), - the frequency 13.56 MHz, and - the frequency 125 kHz. For example, the radio tag 6 operates in the frequency range 20 between 860 MHz and 960 MHz. The radio-tag 6 is a passive radio-tag, that is to say that it has no source of electrical energy embedded in the radio-tag. In other words, the radio-tag 6 is only powered from the energy picked up by the antenna 14. The reader 8 is able to establish the link 30 with the radio-tag 6 and thus to read this 6. For this purpose, the reader comprises: - an antenna 32, - a radio transceiver 34 directly connected to the antenna 32, - a programmable electronic calculator 36 able to execute instructions stored in a memory, and a memory 38. The memory 38 contains the instructions necessary for the reader 8 to be able to read the radio-tag 6 and, in particular, to be able to detect that the temperature of the radio-tag 6 has exceeded the threshold ST. The reader 8 is for example identical to that described in the article A1. Thus, only the details necessary for understanding the invention are given here. The reader 8 is capable of automatically adjusting the frequency fr of the electromagnetic wave used to establish the link 30. More specifically, the reader 8 is able to automatically select the frequency fr for which the rate T of 40 energy transfer between the reader 8 and the radio-tag 6 is greater than a predetermined limit a. For example, the limit a is greater than or equal to 0.8 or 0.9. This rate T is defined in Chapter III of Article A1. Thus, its definition is not repeated here. It will be recalled simply that this rate T is between 0 and 1 and that for an electromagnetic wave received by the radio-tag, the closer it is to 1, the greater the amount of electrical energy that can be recovered by the radio-tag from this electromagnetic wave is important. This rate T depends on the input impedance of the chip 16 and the impedance of the antenna 14. For example, this rate T is defined by the following relationship: T = 4R, R, / IZ, + Z , 2, where: - Ra and R, are the resistances, respectively, of the antenna 14 and the input impedance 10 of the chip 16, - Za and Z, are the impedances, respectively, of the antenna 14 and the input impedance of the chip 16. When the rate T is greater than the limit a, the reader 8 can read a radio-tag further away from the reader or, for a given distance, read this radio-15 tag with a less powerful electromagnetic wave. Here, as in the article A1, to indicate to the reader 8 that the temperature of the radio-tag has exceeded the single ST, the impedance of the antenna 14 is changed. This results in a change in the frequency range where the rate T is greater than the limit a. Here, the frequency range for which the rate T is greater than the limit a, when the temperature of the radio tag 6 is lower than the threshold ST, is denoted [fcL; FCH]. The frequency range for which the rate T is greater than the limit a, when the temperature of the radio-tag is greater than the threshold ST, is denoted [fFIL; fFiFi]. Preferably, when the temperature of the radio-tag 6 is below the threshold ST, outside the range [fcL; fcH], the rate T decreases very rapidly 25 to be zero or almost zero. Similarly, when the temperature of the radio tag is greater than the threshold ST, outside the range [fFIL; fFiFi], the T-rate decreases very rapidly and is also almost nil outside this range. Here, as described in more detail below, the modification of the impedance of the antenna 14 caused by the crossing of the threshold ST is sufficiently important so that there is no common frequency between the ranges [fcL ; fFiFi]. Thus, if the fcH] and [f, HL frequency automatically chosen by the reader 8 to read the radio-tag 6 is in the range [fcL; fcH], then the reader 8 automatically deduces that the temperature of the radio-tag has remained below the threshold ST. Conversely, if the frequency automatically chosen by the reader 8 to read the radio-tag 6 is in the range [fFIL; fFiFi], then the reader 8 deduces that the temperature of the radio-tag 6 has exceeded the threshold ST. For this, the reader 8 has in its memory a table 39 which associates the range rfcL; fcH] to an indication tc coding that the temperature of the radio-label 6 is below the threshold ST. This table 39 also associates the range [fFIL; A signal tH that encodes the temperature of the radio tag 6 has exceeded the threshold ST. Note that in this embodiment, although the radio-label 6 has a single chip 16 and a single antenna 14, the reader 8 is able to read 5 this chip as well in the case where its temperature is lower only in the case where its temperature is above the threshold ST. Thus, whatever the temperature of the radio-tag 6, the reader 8 can read its identifier 24. The reader 8 is connected to the apparatus 10 to transmit to it the data read in the radio-label 6. By For example, the reader 8 transmits to the apparatus 10 the identifier 10 24 read in the radio-tag 6 as well as the indication tc or tH deduced from the frequency fr used to read the radio-tag 6. For example , the apparatus 10 is equipped with a central unit 40 and a screen 42 for displaying on this screen directly readable and understandable by a human being the data read in the radio-label 6. 15 [0043] The radio label 6 comprises a blade 66 (FIGS. 3 and 4) which modifies the inductance of the antenna 14 in response to the crossing of the threshold ST by the temperature of this radio-tag. For this, in this embodiment, this blade 66 is deformed in flexion between a remote position, shown in FIG. 3, and a close position shown in FIG. 4. In this embodiment, the deformation of the blade between its distant and close positions are reversible. Thus, if the temperature of the radio-tag 6 drops below the threshold ST, the blade returns to its remote position. FIG. 2 shows the antenna 14 in greater detail. The antenna 14 has a specific inductance typically greater than 0.5 pH and, preferably, greater than 1 pH regardless of the position of the blade. For this purpose, here, the antenna 14 is in the form of a spiral. More specifically, it comprises an electrical track 50 which wraps around a vertical central axis while progressively moving away from this central axis. The track 50 makes several full turns around this central axis to form several turns. The number of turns is set so that the self-inductance of the antenna 14 is greater than the threshold mentioned above. Conventionally, the track 50 wraps around a central space 52. This central space 52 has, for example, a surface in a horizontal plane greater than 1 cm 2 or 2 cm 2 and generally less than 25 cm 2 or 10 cm2. The chip 16 is fixed on the substrate 12 within this central space 52. In addition, the smaller-area horizontal rectangle which completely contains the track 50 has, for example, a surface area of less than 30 cm 2 or 25 cm 2 and, preferably, an area of less than 5 cm 2 or 3 cm 2. The number of turns of the antenna 14 is often greater than 2, 4 or 5. The antenna 14 also comprises a rectilinear strand 54 directly connected, on one side, to the transceiver 18 and on the other side, at the inner end of track 50. Here, this strand 54 is a straight extension of runway 50. The width of runway 50, in a horizontal direction, is generally comprised of between 100 μm and 2 mm. The thickness tA of the track 50, in a vertical direction, is generally between 1 μm and 500 μm. In FIG. 3, ts is also the thickness of the substrate 12. Here, the thickness ts is constant and is, for example, between 100 μm and 5 mm. The track 50 and the strand 54 are for example made of copper. FIG. 3 represents the elements situated under the antenna 14. The radio-tag 6 comprises a parallelepipedal casing delimiting an internal cavity 60. More specifically, the casing 58 has right and left vertical walls 63 ending in FIG. by upper edges defining an opening which opens into the cavity 60. These upper edges are here fixed, without any degree of freedom, directly on a lower face of the substrate 12, so that the substrate 12 completely closes this opening. The entire track 50 of the antenna 14 is here deposited above the cavity 60. Typically, the housing 58 is a rigid housing, that is to say at least as rigid as the substrate 12 and, preferably, more rigid than the substrate 12. [0050] The blade 66 is entirely housed inside the cavity 60. The blade 66 is made of an electrically conductive material. In this embodiment, this blade 66 comprises two fixed parts 68 and 70 directly anchored, without any degree of freedom, respectively, to the vertical walls 62 and 63. The blade 66 also comprises a movable portion 72 which extends between its two fixed parts 68 and 70. The fixed parts 68 and 70 correspond to the right and left transverse edges of the blade 66. The blade 66 is here curved downwards, that is towards the bottom of the housing 58. Thus, the movable portion 72 is below, in the vertical direction, the fixed portions 68 and 70. In the remote position, the movable portion 72 is spaced a maximum distance h from the underside of the substrate 12. the close position (FIG. 4), the movable portion 72 is spaced a maximum distance h from the underside of the substrate 12. The distance h is typically 1.5 times or 2 times smaller than the distance h, . For example, the distance h is greater than or equal to 5 mm or 1 cm and the distance h is less than or equal to 2 mm or 3 mm. The maximum deflection A, ax between the distant and near positions of the blade 66 is equal to the difference between the distances h, and h ,. This maximum deflection is at least greater than 1 mm and, preferably, greater than or equal to 3 mm or 5 mm or 7 mm. The displacement of the blade 66 between its remote and close positions results in a change in the distance between the antenna 14 of the movable portion 72. Since the blade 66 is made of an electrically conductive material 40, this significantly modifies the inductance of the antenna 14. Here, it is considered that a change in the inductance of the antenna 14 is important when the inductance varies by more than 10% and preferably , by more than 20% or 30% with respect to the value of the inductance of the antenna 14 in the position remote from the blade 66. It is this modification of the inductance of the antenna 14 that is translated into by the existence of two distinct ranges [fcL; fcH] and [fHL; FHH]. In this embodiment, the displacement of the blade 66 between its remote and close positions is obtained by producing the blade 66 in a material both transducer and electrically conductive that transforms the temperature variation of the radio-tag 6 when it crosses the threshold ST in a sudden mechanical deformation of the blade 66. For this purpose, here, the blade 66 is formed solely of a single block of transducer material. When the temperature of the radio-tag 6 exceeds the threshold ST, the blade 66 narrows abruptly which makes it abruptly move from the remote position to the close position. For this, the transducer material used to make the blade 66 is a shape memory material. By shape memory material is meant here a material whose elongation rate is greater than 1% or 2% in response to a temperature variation typically of at least 2 ° C and, for example, 5 ° C or 10 ° C or 20 ° C. The rate of elongation is the AUL ratio between the amplitude AL of the deformation measured along the axis where this deformation is maximum over the length L of this material measured along the same axis. This significant variation in the length of the shape memory material is obtained when its transition temperature is exceeded. Here, the shape memory material is chosen so that its transition temperature is equal to the threshold ST at plus or minus 5 ° C near or plus or minus 1 ° C. It will also be appreciated that typically a shape memory material shrinks abruptly as its temperature exceeds its transition temperature. In other words, it exhibits a behavior opposite to that obtained by a simple thermal expansion. In this embodiment, the memory material is, typically, a shape memory alloy. Thus, the blade 66 fulfills both the function of the actuator 30 and the reflective function of the electromagnetic waves emitted by the antenna 14. For example, the shape memory material used is Nitinol which is an alloy of nickel and titanium and whose Young's modulus at 25 ° C. is typically greater than 150 GPa. [0055] FIG. 5 shows the blade 66 in more detail. In this embodiment, the blade 66 is rectangular and the direction in which its deformation is maximum is parallel to the longer side of the blade 66. that is, parallel to longitudinal edges 74 and 76. The edges 74 and 76 are not directly attached to the vertical walls of the housing 58 to allow the blade 66 to flexibly move between its remote and near positions. The transverse edges, i.e., the smaller sides of the blade 66, correspond to the fixed portions 68 and 70. The dimensions of the blade 66 are such that its orthogonal projection on the underside of the substrate contains at least 50% and, preferably, at least 70% or 90% and even more advantageously 100% of the orthogonal projection of the antenna 14 on this same face. Thus, the minimum dimensions of the blade 66 are derived from the dimensions of the antenna 14. Conversely, it is generally not necessary that the dimensions of the blade 66 are much larger than those of the antenna 14 The operation of the radio-tag 6 is deduced from the explanations previously given. FIG. 6 represents a radio-tag 100 that can be used in place of the radio-tag 6 in the set 2. It is identical to the radio-tag 6 except that the chip 16 is replaced by a simple electrical charge 102 electrically connected between the two ends of the antenna 14. In FIG. 6, the dotted track which electrically connects a terminal of the load 102 to the outer end of the antenna 14 indicates that this track is, for example, made on the underside of the substrate 12 opposite its upper face. In this embodiment, the load 102 is a capacitor which forms with the antenna 14 a resonant LC circuit. The LC circuit thus formed resonates at a resonant frequency fRi when the blade 66 is in its remote position and has a frequency fR2 in the close position. The capacitance of the capacitor 102 and the value of the self-inductance of the antenna 14 are adjusted so that the frequencies f R 1 and f R 2 coincide with frequencies that the reader 8 is capable of transmitting. Under these conditions, when the blade 66 is in its remote position, the rate T is maximum for an electromagnetic wave emitted at the frequency fRi. On the other hand, when the blade 66 is in its close position, the rate T is maximum for an electromagnetic wave emitted at the frequency fR2. The reader 8 is therefore able to read the information that the threshold ST is exceeded or not in the same way as with the radio-label 6. However, in this simplified embodiment, no electronic chip n ' is used. Consequently, the identifier 24 of the radio-tag is not transmitted to the reader 8. FIG. 7 represents a radio tag 110 that can be used in place of the radio tag 6 as a whole. 2. The radio label 110 is identical to the radio label 6 except that the blade 66 is replaced by a blade 112. The blade 112 has a central fixed portion 114 fixed without any degree of freedom in the center of the underside of the substrate 12 Here, this fixed portion 114 is located under the chip 16. On either side of this fixed portion 114 extend two movable portions 116 and 118. The remote and close positions of the movable portions 116 and 118 are represented, respectively. , in solid lines and in broken lines in FIG. 7. As in the previous embodiment, when the temperature of the blade 112 passes the threshold ST, the moving parts 116 and 118 come closer to the antenna 14.
    [0003] The rest of the operation of the radio label 110 is deduced from the operation of the radio label 6. [0061] FIG. 8 represents a radio tag 120 that can be used instead of the radio tag 6 in the set 2. The radio label 120 is identical to the radio label 6 except that the housing 58 and the blade 66 are replaced, respectively, by a housing 124 and a blade 126. The housing 124 is identical to the housing 58 except that it further comprises a central leg 128 which projects from the bottom of this housing 58 in the direction of the chip 16. The blade 126 is identical to the blade 66 except that it comprises: a fixed central portion without no degree of freedom on the upper end of the foot 128, and - two moving parts 132 and 134 located on either side of the fixed part 130. In FIG. 8, the close and remote positions of the blade 126 are represented, respectively, in terms of full and in dashed lines. In this embodiment, in the close-up position, the blade 126 extends mainly in a horizontal plane and under the entire track 50 of the antenna 14. In the remote position, the moving parts 132, 134 curl up on themselves in a direction parallel to the plane of the substrate 12. For example, the moving parts 132, 134 curl up on themselves by folding in the manner of an accordion. Therefore, once the movable portions 132, 134 are curled up, the blade 126 is no longer or substantially further beneath the track 50. In this embodiment, the blade 126 moves from its close position to its position. remote in response to the exceeding of the threshold ST by the temperature of the radio tag 120. FIG. 9 represents a radio tag 140 that can be used in place of the radio tag 6 in the set 2. The radio label 140 is identical to the radio label 6 except that the blade 66 is replaced by two blades 142 and 144. The blade 142 and identical to the blade 66 except that it has only one fixed portion 146 anchored in the vertical wall 63 of the housing 58. The end 148 of the blade 142 opposite its fixed portion 146 is left free to move within the cavity 60. The movable portion 150 of the blade 142 extends from the fixed portion 146 to the free end 148. The end 148 is for example located vertically of the central portion 52 of the antenna 14. The remote and close positions of the blade 142 are shown, respectively, in solid lines and in broken lines in FIG. remote position, the end 148 is further away from the lower face of the substrate 12 than in the close position. The blade 144 is derived from the blade 142 by symmetry with respect to a vertical plane passing through the center of the chip 16 and parallel to the wall 63. The operation of the radio label 140 is deduced from the operation of the radio label FIG. 10 shows a radio tag 160 that can be used in place of the radio tag 6 in the set 2. The radio tag 160 is identical to the radio tag 6 except that the blade 66 is replaced by a blade 162. The blade 162 is identical to the blade 66 except that its transverse edges 164 and 166 are not directly anchored, without any degree of freedom, in the vertical walls 62 and 63. Here, the transverse edges 164, 166 are mechanically connected to the vertical walls 63, 62, respectively, by strands 166 and 168. The strand 166 has one end anchored in the wall 63 and another opposite end attached to the transverse edge 164. The strand 166 allows the edge 164 to pivot around the anchor point 10 of this strand in the wall 63. The strand 166 is not made of a transducer material. By cons, it may or may not be made of an electrically conductive material. Strand 168 is symmetrical with strand 166 with respect to a vertical plane passing through the center of chip 16 and parallel to wall 63. In FIG. 10, the remote and close positions of blade 162 are shown. , respectively, in solid lines and dashed lines. When the temperature of the radio tag 160 exceeds the threshold ST, the blade 162 shrinks sharply in its longitudinal direction, which causes a simultaneous pull on the strands 166 and 168 and thus an upward movement of the blade 162 which is close to the bottom face of the substrate 12. [0070] FIG. 11 represents a radio-tag 180 identical to the radio-tag 6 except that the blade 66 is replaced by a blade 182. The blade 182 is identical to the blade 66 except that it is made of magnetostrictive material or magnetic form memory and not in a thermal shape memory material. Here, by magnetostrictive material, is meant a material whose absolute value of the saturation magnetostriction coefficient Δs is greater than 10 ppm (parts per million) and, preferably, greater than 100 or 1000 ppm. The coefficient ss is defined by the following relation ss = AUL, where ΔL is the amplitude of the deformation of the magnetostrictive material along the direction where its deformation is maximal and L is the length of this material in this direction in the absence of a field. 30 magnetic. For example, the magnetostrictive material is Terfenol-D or a FeSiB alloy or a FeCo alloy. In this case, the magnetostriction coefficient λs of this material is strictly positive. The magnetostrictive material may also have a magnetostriction coefficient Δs negative. For example, in this case, the magnetostrictive material is Sam FeNol which is a samarium alloy. A magnetic shape memory material is a material which works as described for thermal shape memory materials except that its deformation is triggered by a variation of the magnetic field and not by a change in temperature. As with thermal shape memory materials, the magnetic shape memory material has an elongation rate greater than 1% or 2%. For example, it may be a NiMnGa alloy. The radio-tag 180 operates as the radio-tag 6 except that it is a variation of the amplitude of the magnetic field created, for example, by a magnet, a coil or any other external magnetic field source to which The radio tag 180 is exposed which varies the impedance of the antenna 14. [0074] Many other embodiments are possible. For example, the radio tag may comprise a battery or an additional energy recovery system and thus behave as a semi-passive or active radio-tag. Other shapes of the antenna 14 are possible. For example, the antenna may also be meander shaped. In this case, the antenna extends along a longitudinal axis of the upper face of the substrate and has several strands arranged one after the other along this longitudinal axis. Each of these strands forming a segment, for example rectilinear, which intersects the longitudinal axis at a single point. These strands are electrically connected to each other by other strands entirely located on one side of this longitudinal axis. A meandering antenna is for example represented in the article Al. The antenna can also be shaped in "T" as described in the article A1. It is also possible to use "slot" versions of these antennas, these antennas characterizing then by an absence of material ("slit") locally in the metal constituting the antenna. The arrangement of the chip 16 may be different. For example, the transceiver 18 may be integrated within the computer 20. [0077] In another embodiment, the electrical load 102 is replaced by a resistor. It can also be replaced by a simple wired link. In this case, the reader 8 detects the change in the mutual inductance between the antenna 32 and the antenna 14 to detect whether the temperature threshold ST has been crossed or not. Many other embodiments of the blade are possible. For example, several different shape memory materials can be used to make different parts of the blade. These shape memory materials 30 then each have a transition temperature different from the other shape memory materials used. For example, a first portion of the blade is made of a first shape memory material having a transition temperature T1 and another portion of the blade is made of a second shape memory material having a larger T2 transition temperature. that temperature T1. Under these conditions, if the temperature of the blade is lower than the temperature T1, this corresponds to a first position of the blade and therefore to a first value of the impedance of the antenna. If the temperature of the blade is between the temperatures T1 and T2, the blade is deformed to reach a second position and therefore a second value of the impedance of the antenna. Finally, if the temperature of the blade exceeds the temperature T2, the blade deforms, for example even further, to reach a third position in which the antenna has a third inductance value. The reader 8 can detect what is the value of the current inductance of the antenna and thus determine the temperature range of the antenna. Thus, the use of different shape memory materials makes it possible to detect the crossing of several temperature thresholds. In another embodiment, it is also possible to use several blades, each blade having a transition temperature different from that of the other blades. It is thus possible to detect the crossing of several different temperature thresholds. For example, the blade 144 is made of a shape memory material having a transition temperature different from that of the blade 142. [0080] In another variant, the blade 66 is in its close position when the temperature of the blade The radio tag is below the threshold ST and in its remote position when the temperature of the radio tag is above this threshold ST.
    [0004] For this, the blade 66 is for example curved on the side opposite to that shown in Figure 3. Under these conditions, the narrowing of the blade 66 when its temperature exceeds the threshold ST brings the blade to its remote position. The blade may be shaped so that the deformation between the remote and close positions is irreversible. For this purpose, it is possible to proceed as described in the article A1. The blade 66 need not be systematically rectangular. For example, it can be square or elliptical or any other possible form. Other modulation methods may be used to transmit data between the reader and the radio tag. For example, the antenna 14 is electrically connected with a variable capacitor to form a resonant LC circuit. The transceiver 18 modifies the value of this capacitor as a function of the value of the bit or the group of bits to be transmitted. This then changes the value of the resonance frequency of the LC circuit. The reader detects this change in the resonance frequency of the LC circuit and deduces the value of the bit or group of 30 bits transmitted. This communication protocol works particularly well when the antennas of the reader and the radio-tag are coupled by magnetic induction. This protocol is therefore generally used in the near field, that is to say when the antennas 14 and 32 are separated by a distance less than λ / (2-rr), where 35 - λ is the wavelength of the electromagnetic wave used to communicate between these antennas, and - 7 is the number Pi. [0084] In another variant, it is the inductance of the antenna which is modified by the transceiver 18. For this, the transceiver 18 controls an electrical switch 40 which modifies the inductance of the antenna. These two embodiments are, for example, described in detail on page 21 of the following Youbok Lee article: "Antenna Circuit Design for RFID applications," Microchip Technology INC, 2003, Technical Note AN710. The detection of the crossing of the threshold ST can also be detected by the reader 8 simply by the fact that he can not establish the connection 30 with the radio-tag while the latter is situated at a distance where, in the absence of modification of the inductance of the antenna, the connection could have been established. For example, for this, the radio-tag is always placed beyond a minimum distance between the reader and the radio-tag and within a maximum distance beyond which the reader can not normally establish. the link 30 with this radio-tag. Under these conditions, when the temperature is below the threshold ST, the reader 8 is able to establish the connection 30 with the radio-tag 6. In the opposite case, that is to say if the temperature has exceeded the threshold ST , the reader can not establish the link 30, which indicates that the temperature of the radio-tag 6 has crossed the threshold ST. In this simplified embodiment, it is not necessary for the reader to be able to automatically choose the frequency for which the transfer rate T is greater than the limit a. Typically, in this case, the read frequency of the radio-tag is fixed once and for all. [0086] All the embodiments and variants described above also apply to the case where the transducer material used is a magnetostrictive or magnetic-shape memory material.
    权利要求:
    Claims (9)
    [0001]
    REVENDICATIONS1. Radio-tag capable of indicating to a reader, via a wireless link, that a variation of energy has crossed a predetermined threshold, this variation of energy being chosen from the group composed of a variation of the temperature of the radio-tag and of a variation of the magnetic field in which the radio-tag is immersed, this radio-tag comprising: an electrically insulating substrate; an antenna for establishing the link; wirelessly with the reader, this antenna being entirely deposited and fixed without any degree of freedom on the insulating substrate, a reflector made of electrically conductive material and electrically isolated from the antenna for reflecting at least part of the electromagnetic waves emitted by the antenna, this reflector being movable relative to the antenna between a remote position in which the impedance of the antenna is equal to a first value and a position in which the impedance of the antenna is equal to a second value different from the first value, and an actuator made of a transducer material capable of transforming the variation of energy into a mechanical displacement of the reflector between its remote and close-up when the energy change crosses the predetermined threshold to indicate to the reader this event, the transducer material being selected from a group consisting of a thermal shape memory material, a magnetostrictive material and a memory material of magnetic form, characterized in that: - the transducer material is also an electrically conductive material, and - the reflector and the actuator are both formed by a same blade (66; 112; 126; 142, 144; 162; 182) made in this transducer material and a movable portion of which moves relative to the antenna between the distant and near positions when the energy change crosses the predetermined threshold. 30
    [0002]
    The radio tag of claim 1, wherein the blade has a fixed portion (68, 70; 114; 130; 146) anchored without any degree of freedom to the substrate.
    [0003]
    A radio tag according to any one of the preceding claims, wherein: - two ends of the antenna are electrically connected to each other either directly via an electrical track or through intermediate of an electric charge (102) to form a closed electrical circuit, and the radio-tag is devoid of electronic chip electrically connected to this closed electrical circuit.
    [0004]
    The radio tag according to claim 3, wherein the two ends of the antenna are electrically connected to each other via a capacitor (102) to form a resonant LC circuit whose frequency resonance is a function of the inductance of the antenna.
    [0005]
    A radio tag according to any one of the preceding claims, wherein the transducer material is a thermal shape memory material having an elongation rate greater than 1% in response to a temperature change of 10 ° C. around the predetermined threshold.
    [0006]
    A radio tag as claimed in any one of the preceding claims, wherein the blade is arranged such that movement of its moving portion between the remote and near positions is irreversible.
    [0007]
    7. Radio-tag according to any one of the preceding claims, wherein the amplitude of the maximum deflection (Amax) of the movable portion of the blade 20 between its remote and close positions is greater than 1 mm.
    [0008]
    8. Radio-tag according to any one of the preceding claims, wherein the radio-tag is a passive radio-tag powered solely from the energy of the electromagnetic waves emitted by the reader. 25
    [0009]
    9. An assembly comprising: - a radio-tag (6; 100; 110; 120; 140; 160; 180) able to indicate to a reader, via a wireless link, that a variation of energy has passed a predetermined threshold, this energy variation being chosen from the group consisting of a variation of the temperature of the radio-tag and a variation of the magnetic field in which the radio-tag is immersed, this radio label comprising: - an electrically insulating substrate (12); - an antenna (14) for establishing the wireless connection with the reader, said antenna being entirely deposited and fixed without any degree of freedom on the insulating substrate; reflector of electrically conductive material and electrically isolated from the antenna for reflecting at least a portion of the electromagnetic waves emitted by the antenna, this reflector being movable relative to the antenna between a remote position in which the antenna impedance is equal to a first value and a close position in which the impedance of the antenna is equal to a second value different from the first value, and 5 - an actuator made of a transducer material capable of transforming the variation of energy in a mechanical displacement of the reflector between its distant and near positions when the variation of energy crosses the predetermined threshold so that the frequency range for which the rate of transfer of electrical energy between the reader and the radio label is greater than a predetermined limit, varies at the same time from a first range to a second range in response to the crossing of this predetermined threshold by the variation of energy, these first and second frequency ranges having no frequencies. common, the transducer material being selected from a group consisting of a thermal shape memory material, a material magnetostrictive and magnetic memory material, and - the reader (8) adapted to emit an electromagnetic wave at an interrogation frequency to read the radio-label, this reader being able to automatically choose the frequency of interrogation to be used so that the rate of transfer of electrical energy between the reader and the radio-label is greater than the predetermined limit, this reader further comprising a pre-recorded table (39) which associates with the first and second frequency ranges indications, respectively, of not crossing and crossing the predetermined threshold, and the reader is able to transmit to an external device the indication which is associated, by the prerecorded table, to the interrogation frequency automatically chosen and used to interrogate the radio tag, characterized in that the radio tag (6; 100; 110; 120; 140; 160; 180) is according to any one of the preceding claims.
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    同族专利:
    公开号 | 公开日
    US9805299B2|2017-10-31|
    US20160364642A1|2016-12-15|
    EP3107044A1|2016-12-21|
    FR3037425B1|2017-07-14|
    EP3107044B1|2018-05-16|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2004015624A2|2002-08-07|2004-02-19|Marconi Intellectual Property Inc.|Environmentally sensitive multi-frequency antenna|
    WO2012131143A1|2011-03-30|2012-10-04|Upm Rfid Oy|Radio-frequency identification tag with activation portion|
    KR101325159B1|2012-01-05|2013-11-06|포항공과대학교 산학협력단|RFID sensing device, capable of temperature measurement|
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    AU2018318950A1|2017-08-15|2020-02-27|Composecure, Llc|Card with dynamic shape memory alloy tactile feature|
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    法律状态:
    2016-07-08| PLFP| Fee payment|Year of fee payment: 2 |
    2016-12-16| PLSC| Search report ready|Effective date: 20161216 |
    2017-06-30| PLFP| Fee payment|Year of fee payment: 3 |
    2018-06-27| PLFP| Fee payment|Year of fee payment: 4 |
    2020-03-13| ST| Notification of lapse|Effective date: 20200206 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1555450A|FR3037425B1|2015-06-15|2015-06-15|RADIO TAG|FR1555450A| FR3037425B1|2015-06-15|2015-06-15|RADIO TAG|
    EP16173848.9A| EP3107044B1|2015-06-15|2016-06-10|Radio tag|
    US15/183,082| US9805299B2|2015-06-15|2016-06-15|Radio-frequency identification tag|
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