Temperature indicator

Abstract

A temperature indicator includes a microsensor having a sensing element having a first layer coupled to a second layer, wherein the first and second layers have different coefficients of thermal expansion. The sensing element is configured to move from a first position to a second position in response to exposure to a temperature event, and has a detection circuit configured to change from a first state to a second state in response to the sensing element moving to the second position. The detection circuit is prevented from returning to the first state in response to the change to the second state. A radio frequency identification (RFID) module is coupled to the detection circuit and configured to output a value indicating that the sensing element is in the second position. An activator element is configured to hold the sensing element in the first position until the activator element is removed from the microsensor.

Description

Background of the invention:

[0002] Many types of objects require monitoring or tracking during manufacturing, storage, or transportation due to their temperature sensitivity or fragility. For example, certain types of objects may be easily damaged if exposed to specific temperatures (e.g., food or pharmaceuticals). Therefore, for quality control purposes and / or general monitoring of transportation conditions, it is necessary to determine and / or verify the environmental conditions to which objects are exposed. Invention Overview:

[0004] According to one aspect of this disclosure, an apparatus and technique for temperature detection are disclosed. The temperature indicator includes a microsensor having a sensing element, the sensing element having a first layer coupled to a second layer, wherein the first layer and the second layer have different coefficients of thermal expansion. The sensing element is configured to move from a first position to a second position in response to exposure to a temperature event. The microsensor also includes detection circuitry configured to change from a first state to a second state in response to the movement of the sensing element from the first position to the second position. The detection circuitry is prevented from returning to the first state in response to the change to the second state. The indicator also includes a radio frequency identification (RFID) module coupled to the detection circuitry, wherein the RFID module is configured to output a value indicating that the sensing element is in the second position. The indicator also includes an activator element configured to hold the sensing element in the first position until the activator element is removed from the microsensor.

[0005] According to another embodiment of this disclosure, the temperature indicator includes a substrate having a communication module inlay configured to transmit the actuation state of the indicator, a microsensor communicatively coupled to the communication module inlay for detecting temperature events, wherein the microsensor has an irreversible detection circuit configured to detect the actuation state, and an activator element configured to keep the microsensor in a non-responsive state until the activator element is removed from the microsensor.

[0006] According to another embodiment of this disclosure, the temperature indicator includes a microsensor configured to activate in response to receiving a temperature event. The microsensor includes a detection circuit configured to change from a first state to a second state in response to activation of the microsensor, and the detection circuit is prevented from returning to the first state in response to activation. The indicator also includes a radio frequency identification (RFID) module coupled to the detection circuit, wherein the RFID module is configured to output a value indicating that the microsensor has been activated. The indicator also includes an activator element configured to hold the microsensor in a non-responsive state until the activator element is removed from the microsensor.

[0007] Brief description of the attached figures

[0008] To gain a more complete understanding of this application and its objectives and advantages, please refer to the following description in conjunction with the accompanying drawings, wherein:

[0009] Figure 1 An application diagram of a temperature indicator embodiment according to the present disclosure is shown;

[0010] Figure 2 A block diagram of an embodiment of a temperature indicator according to the present disclosure is shown;

[0011] Figure 3 An exploded view of an embodiment of a temperature indicator according to the present disclosure is shown;

[0012] Figure 4 It is shown that, according to this disclosure Figure 3 A partially enlarged view of the temperature indicator shown;

[0013] Figure 5 It is shown that, according to this disclosure Figure 3 and Figure 4 A schematic diagram of an embodiment of a temperature indicator micro-sensor is shown;

[0014] Figure 6 This shows the device in an actuated state according to this disclosure. Figure 5 A schematic diagram of a temperature indicator embodiment; and

[0015] Figure 7 The following is shown in accordance with this disclosure: Figure 5 and Figure 6 A partially enlarged view of the temperature indicator shown.

[0016] Detailed description

[0017] Embodiments of this disclosure provide apparatus and techniques for temperature detection and indication. According to one embodiment, a temperature indicator includes a microsensor with a sensing element having a first layer coupled to a second layer, wherein the first and second layers have different coefficients of thermal expansion. The sensing element is configured to move from a first position to a second position in response to exposure to a temperature event. The microsensor also includes detection circuitry configured to change from a first state to a second state in response to the movement of the sensing element from the first position to the second position. The detection circuitry is prevented from returning to the first state in response to the change to the second state. The indicator also includes a radio frequency identification (RFID) module coupled to the detection circuitry, wherein the RFID module is configured to output a value indicating that the sensing element is in the second position. The indicator also includes an activator element configured to hold the sensing element in the first position until the activator element is removed from the microsensor. Embodiments of this disclosure enable temperature event detection without using an internal power supply. The RFID module can detect the state of a switching circuit and emit or output a value indicating the indicator's activation state. For example, in some embodiments, an RFID reader can be used to activate the RFID module and determine the actuation state of the temperature indicator device. Furthermore, embodiments of this disclosure utilize microsensors (e.g., micromechanical and / or microelectronic components) to detect temperature events, these microsensors having circuitry that causes an irreversible actuation state of the indicator after a temperature event is detected. Additionally, embodiments of this disclosure enable on-site activation of the indicator (i.e., keeping the indicator in a non-responsive state), ensuring that temperature events detected before the indicator's intended application do not inadvertently activate it.

[0018] Many types of objects require temperature monitoring during storage, transportation, or use (i.e., the cold chain). For example, some types of objects, such as food or medicine, may easily spoil or become ineffective if exposed to excessively high temperatures for extended periods. The duration or threshold of temperature deviation (i.e., the "time-temperature" variable) is often more important than non-duration or real-time temperature readings. Therefore, for quality control purposes and / or general monitoring of transportation / use conditions, the temperature conditions to which objects are exposed should be determined and / or verified.

[0019] Refer to the attached figures, especially the figures... Figure 1 Example diagrams of a temperature indicator 10 are provided, in which illustrative embodiments of the present disclosure may be implemented. Figure 1 A front view of the temperature indicator 10 is shown. Figure 1In this embodiment, indicator 10 is a portable device configured to be attached to or disposed within a transport container containing an object for which relevant temperature events are to be monitored. Embodiments of temperature indicator 10 monitor whether the object is exposed to specific temperatures or environments during manufacturing, storage, and / or transport. In some embodiments, temperature indicator 10 may be attached to the transport container using, for example, adhesive materials, permanent or temporary fasteners, or various different types of attachment devices. The transport container may include a container in which the monitored object is loosely placed, or it may include the monitored object itself. It should be understood that... Figure 1 These are merely illustrative examples and are not intended to assert or imply any limitation on the environment in which different embodiments of the invention are practiced.

[0020] exist Figure 1 In the illustrated embodiment, the temperature indicator 10 includes a housing 12 in which a temperature sensing, temperature-sensitive, and / or temperature detection component 14 is disposed. In the illustrated embodiment, the detection component 14 is configured to detect and indicate temperature events relative to the indicator 10 (e.g., detecting when the indicator 10 (and correspondingly, the container associated with the indicator 10) has reached a specific ambient temperature). In some embodiments, the housing 12 is constructed and / or constituted of a transparent or translucent material having a masking label 16 located on its front side or affixed thereto. In some embodiments, the masking label 16 is configured to have one or more holes or “windows” 18 for providing a visual indication of temperature detection. For example, in some embodiments, in response to the indicator 10 experiencing a specific temperature, the detection component 14 causes a visual indication to be displayed within or through one or more windows 18 to provide a visual indication that the monitored object has or may have been subjected to a certain temperature level. However, it should be understood that other methods can be used to provide a visual indication that the detection component 14 has been moved and / or otherwise placed in an actuated state, indicating that the indicator 10 has experienced some degree of temperature. It should also be understood that the housing 12 may be configured and / or manufactured from other materials, such as an opaque material in which one or more windows 18 are formed. In some embodiments, the housing 12 may be configured to have no windows 18. For example, as will be described in more detail below, the indicator 10 may be configured to provide visual and / or non-visual indication of whether the indicator 10 has experienced a temperature condition (e.g., by using a radio frequency identification signal).

[0021] Figure 2 A block diagram illustrating an embodiment of the indicator 10 according to this disclosure is provided. Figure 2In this embodiment, indicator 10 includes a microsensor 20 and a wireless communication module 22. The microsensor 20 is a micromechanical and / or microelectronic device (e.g., a microscopic device or system, typically having a micrometer-sized component with an overall size usually measured in square millimeters) used to detect temperature events (e.g., temperatures exceeding a certain threshold). The microsensor 20 can be configured as a microelectromechanical system (MEMS) device (e.g., using silicon or other materials in processes or techniques for creating desired shapes / components by depositing material layers, patterning by photolithography, and etching), a liquid crystal display (LCD) panel fabrication device (e.g., a device fabricated using glass components and / or glass substrates through LCD manufacturing processes such as patterning, lamination, masking, dicing, and thin-film transistor (TFT) deposition techniques, which may or may not include liquid crystals), and / or formed using roll-to-roll (R2R) processing techniques (e.g., forming the device on a roll of flexible plastic, metal foil, or flexible glass). In some embodiments, the temperature indicator 10 may be (permanently or removably) fixed to a printed circuit board and / or otherwise permanently or removably connected to electronic circuitry (e.g., a removable housing) such that, in response to receiving and / or detecting a temperature condition of sufficient magnitude and / or exceeding a certain threshold, the temperature indicator 10 provides an electronic signal / indication of such an event.

[0022] In some embodiments, the microsensor 20 includes a detection circuit 24. The detection circuit 24 may include one or more switching elements, traces, contacts, and / or circuitry that responds to changes in the actuation state of the detection sensor 20. For example, in some embodiments, the sensor 20 may include a movable element or component that moves or displaces in response to a temperature event. Displacement of the movable element may cause a change in the state of the circuit 24 (e.g., an impedance change, from an open-circuit state to a closed-circuit state, or vice versa). The wireless communication module 22 is configured to wirelessly transmit information associated with the state of the circuit 24, indicating the actuation state of the indicator 10 (e.g., based on the open or closed state of the circuit 24). For example, in one embodiment, the wireless communication module 22 includes a radio frequency identification (RFID) module 30. In some embodiments, the RFID module 30 includes a passive RFID module 30 (e.g., a passive RFID tag) having an RFID integrated circuit or circuitry 32 (e.g., disposed on or as part of a printed circuit board), a memory 34, and an antenna 36. As a passive RFID module 30, the indicator 10 does not contain a battery (e.g., it is powered by the RFID reader 40), thus forming a battery-free temperature indicator 10. For example, when the module 30 encounters radio waves from the reader 40, the antenna 36 generates a magnetic field, thereby powering the module 30 to activate the circuit 32. Once powered / activated, the module 30 can output / transmit information encoded in the memory 34 (e.g., using communication protocols such as NFC, ISO-18000-3, ISO 18000-6, UHF Gen2, ISO-15693, etc.). However, it should be understood that in some embodiments, the RFID module 30 may include an active RFID module 30 that includes a power source (e.g., a battery) that can be configured to broadcast or transmit specific information continuously, intermittently, and / or according to programming or event triggering. One embodiment of a passive RFID tag is a flexible RFID circuit in roll form. In flexible RFID circuits, the chip and antenna are embedded in a substrate as thin as 100 to 200 nanometers through copper etching or hot stamping, using materials such as polyvinyl chloride (PVC), polyethylene terephthalate (PET), phenolic plastics, polyester, styrene, or paper. One process in RFID manufacturing involves screen printing using conductive inks containing copper, nickel, or carbon. Smartrac from Avery Dennison... TM The product is a prime example of a commercially available flexible circuit passive RFID tag, which can be rolled into hundreds or even thousands of tags.

[0023] It should also be understood that the wireless communication module 22 can be configured for other types of wireless communication types, modes, protocols, and / or formats (e.g., Short Message Service (SMS), wireless data using General Packet Radio Service (GPRS) / 3G / 4G or via Wi-Fi over the public Internet, or locally with other wireless communication protocol standards such as Wi-Fi, Z-Wave, ZigBee, Bluetooth, Bluetooth Low Energy (BLE), LoRA, NB-IoT, SigFox, Digital Enhanced Cordless Telecommunications (DECT), or other popular technologies). As will be further described below, in response to the reception of a specific level and / or amplitude of a temperature event, the temperature indicator 10 functions as a passive temperature sensor / indicator, which can be used as part of an electronic signal or circuit. In some embodiments, the temperature sensing capability / function of the temperature indicator 10 of this disclosure does not require a power source in monitoring mode.

[0024] In the illustrated embodiment, memory 34 includes at least two distinct stored and / or encoded values ​​42 and 44. For example, value 42 may correspond to a value output / transmitted by module 30 when detection circuit 24 is in an open-circuit condition or state, while value 44 may correspond to a value output / transmitted by module 30 when detection circuit 24 is in a closed-circuit condition or state. For instance, value 44 may represent an RFID tag identification (ID) number without an active temperature detection circuit 24, and the RFID tag ID number may have an additional character (e.g., "0") placed at its end. Value 42 may represent an RFID ID number with an active temperature detection circuit 24, and the RFID tag ID number may have an additional character (e.g., "1") at its end that is different from the additional character carried by value 44. In the illustrated embodiment, the RFID module 30 (e.g., circuit 32) is coupled to the detection circuit 24 and can detect whether the detection circuit 24 is in an open-circuit or closed-circuit condition or state. Therefore, for example, the detection circuit 24 may initially be in a closed-circuit condition or state. Thus, if powered on / activated, the module 30 transmits value 44 to the reader 40. If the indicator experiences a temperature event, the sensor 20 can cause a change in the circuit 24, which will result in the circuit 24 being in an open-circuit condition or state. Therefore, once powered on / activated (e.g., after a temperature event), the module 30 will instead transmit value 42 to the reader 40. Therefore, embodiments of this disclosure enable the indicator 10 to use an electronic indicator (e.g., a video recognition reader) to monitor for potential damage to sensitive products / objects attached to it due to temperature changes, while the indicator 10 does not contain or require any internal power source (e.g., a battery). In some embodiments, the detection circuit... 24 is configured to be irreversible, such that once the state of detection circuit 24 changes, detection circuit 24 is prevented from returning to a previous state. For example, if detection circuit 24 is in a closed state or condition before sensor 20 is activated, and a temperature event causes sensor 20 to activate, which also causes detection circuit 24 to transition to an open state or condition, then detection circuit 20 is configured to remain in the open state and thus cannot return to the closed state. Similarly, detection circuit 24 may be configured to transition from an open state to a closed state in response to actuation of sensor 20, and thereafter remain in the closed state and cannot return to the open state. Therefore, embodiments of this disclosure prevent any unauthorized reset of temperature indicator 10. It should also be understood that indicator 10 may be configured to have more or fewer values ​​stored in memory 34 (e.g., emitting a single value only when sensor 20 is activated; different values ​​emitting corresponding to different temperature thresholds, etc.).

[0025] This disclosure may include computer program instructions of any level of technical detail integration (e.g., stored in a computer-readable storage medium (or media) such as memory 34) for causing a processor to perform various aspects of this disclosure. The computer-readable program instructions described herein may be downloaded to a suitable computing / processing device (e.g., communication module 22 and / or radio frequency identification module 30). The computer-readable program instructions for performing operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages. In some embodiments, electronic circuitry (e.g., circuit 32) including programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute computer-readable program instructions by personalizing the electronic circuitry with status information from the computer-readable program instructions in order to perform various aspects of this disclosure. Various aspects of this disclosure are illustrated herein with reference to figures and / or block diagrams of methods and / or apparatus according to embodiments of this disclosure. It will be understood that each block of the illustrations and / or block diagrams, and combinations of blocks in the illustrations and / or block diagrams, may represent a module, code segment, or code portion, which may be implemented by computer-readable program instructions. These computer-readable program instructions may be provided to a processor or other programmable data processing apparatus to produce a machine, such that the instructions, executed via the processor, create means for implementing the functions / actions specified in one or more blocks of the illustrations and / or block diagrams. These computer-readable program instructions may also be stored in a computer-readable storage medium that directs a computing device, programmable data processing apparatus, and / or other apparatus to operate in a particular manner, such that the computer-readable storage medium storing the instructions includes one or more block diagrams of the article of manufacture containing instructions for implementing the aspects of the specified functions / actions. The detection circuit 24, the wireless communication module 22, and / or the radio frequency identification module 30 may be implemented using known techniques in any suitable manner, which may be hardware-based, software-based, or some combination of both. For example, detection circuit 24, wireless communication module 22, and / or RFID module 30 may include software, logic, and / or executable code (e.g., software and / or algorithms running on a processor unit, hardware logic in a processor or other type of logic chip, centralized in a single integrated circuit or distributed across different chips in a data processing system) for performing the various functions described herein. As those skilled in the art will understand, aspects of this disclosure can be embodied as systems, methods, or computer program products. Therefore, aspects of this disclosure may take the form of hardware embodiments, software embodiments (including firmware, resident software, microcode, etc.), or embodiments combining software and hardware aspects, which are generally referred to herein as “circuit,” “module,” or “system.”

[0026] Figure 3 This is an exploded schematic diagram of various embodiments of the temperature indicator 10 according to the present disclosure. Figure 4 Showing according to this disclosure Figure 3 A partially enlarged schematic diagram of an embodiment of the temperature indicator 10 shown. (See reference...) Figure 3 The indicator 10 includes a housing or outer casing 50 having a bottom or lower wall 52 and a top or upper wall 54. An RFID module 30 is located between the upper wall 54 and the lower wall 52. Figure 4 An enlarged view of the radio frequency identification module 30 is shown. Figure 3 and 4 In this embodiment, the RFID module 30 includes a substrate 60 with an RFID inlay 62, which, together with an RFID chip or circuitry 32 coupled thereto, forms an antenna 36. In the illustrated embodiment, a microsensor 20 is adhered to and / or coupled to the RFID module 30. For example, in the illustrated embodiment, the sensor 20 may include a MEMS sensor 201, a sensor 202 manufactured from an LCD panel, or a microsensor 203 manufactured using R2R technology. (See reference...) Figure 4 The radio frequency identification (RFID) module 30 includes a mounting area 66 for receiving the microsensor 20, and the RFID module 30 also includes traces or leads 68 for communicating and / or electrically coupling the sensor 20 to the RFID circuit 32.

[0027] refer to Figure 3 In the illustrated embodiment, indicator 10 includes an activator element 70. Activator element 70 is configured to keep sensor 20 in a non-responsive state (i.e., unable to transition from an inactive state to an active state, where the inactive state refers to the state of sensor 20 before receiving a temperature event above a certain threshold, and the active state refers to the state of sensor 20 after experiencing a temperature event at or above the threshold) until activator element 70 is removed from indicator 10. For example, during the delivery of indicator 10 to an end user (or otherwise), indicator 10 may be affected by a temperature event that sensor 20 detects, causing sensor 20 to be in an active state (i.e., indicating that a temperature event has been received). Even if sensor 20 has experienced a temperature event, activator element 70 prevents sensor 20 from transitioning from an inactive state to an active state. Removing activator element 70 from indicator 10 places sensor 20 in an active or sensing mode (i.e., capable of detecting temperature events and transitioning to an active state to indicate that a temperature event has been received).

[0028] For example, as will be described in more detail below, in one embodiment, the activator element 70 includes a retaining element 72 that is adhered to and / or otherwise coupled to an upper wall 54, the upper wall 54 including a barrier 74 extending downward through an opening 80 formed in the upper wall 54. The barrier 74 may be in the form of a pin or other structural member extending downward and engaging at least a portion of the sensor 20 to prevent the sensor 20 from activating. In operation, removing the retaining element 72 from the indicator 10 (e.g., peeling the retaining element 72 from the upper wall 54) also causes the barrier 74 to be pulled outward from the indicator 10, thereby disengaging it from the sensor 20 and enabling the sensor 20 to be actuated in response to the sensor 20 detecting a temperature event.

[0029] Figure 5 A schematic diagram of an embodiment of a temperature indicator 10 is shown, which incorporates a MEMS-type microsensor 20 in an inactive and non-reactive state according to the present disclosure. Figure 6 The active state according to this disclosure is shown. Figure 5 A schematic diagram of an embodiment of indicator 10. Sensor 20 represents at least one of any number of sensors 20 within the indicator 10 assembly (more than one sensor 20 may be required if calibration of the sensor 20 is required).

[0030] In the illustrated embodiment, sensor 20 includes sensing element 100 configured to move in response to exposure to a temperature event (e.g., from a temperature source). Figure 5 The first position or location shown is moved to, for example, Figure 6 The second location or position shown). The sensing element 100 may include a multilayer material, wherein at least two layers have different temperature-sensitive properties. For example, in the illustrated embodiment, the sensing element 100 includes a cantilever structure 102 having layers or beams 104 and 106. Layers are formed with beams 104 and 106 such that one of beams 104 or 106 contains at least one material different from at least one of the other beams 106 or 104. In the illustrated embodiment, beams 104 and 106 are arranged side-by-side or adjacent to each other, parallel (or substantially parallel), and spaced apart from each other to define a gap 108 along their length. In this embodiment, the cantilever 102 is formed as a planar structure. The cantilever 102 may be located with respect to the underlying structure of the sensor 20 (e.g., substrate 60). Figure 3In different planes. In the illustrated embodiment, cantilever structure 102 is characterized as including a beam; however, it should be understood that sensor 20 may include other cantilever or non-cantilever structures, including planar structures such as diaphragms. The term “dual piezoelectric wafer” is generally used to refer to this bending effect of a single beam formed by two active layers, and the term will be used herein to more generally refer to the bending effect of a combination of different materials in response to changes in the parameter of interest in a cantilever structure. In particular, different materials have inconsistent expansion / contraction (elongation / contraction) responses to the relevant parameter, causing the cantilever structure to bend toward the beam that contracts more or elongates less than the other beam. If the parameter is at a sufficiently high (threshold) level, the deflection of the cantilever structure is sufficient to disconnect or close (depending on the operating mode of the sensing device) its associated electrical contacts, which can be used to interrupt or allow the transfer of charge or current, the generation of voltage, or to provide another form of output corresponding to a digital signal, respectively. The contact between the cantilever structure and the electrical contacts is referred to herein as a contact-mode switching function or contact-mode operation, and in some embodiments is non-locking (i.e., the cantilever structure is not mechanically locked or otherwise secured to the contacts unless bending or deflection occurs).

[0031] In a preferred embodiment, the characteristic change of the sensing element 100 in response to the parameter is temporary and reversible. For example, if the sensing element 100 responds to temperature (thermal expansion or contraction), the final response (deflection) of the cantilever structure 102 is temporary, and the cantilever 102 will return to its original configuration after the temperature shift ends, unless it is mechanically restricted (e.g., by locking the bent cantilever or otherwise restricting the cantilever 102 from returning to its original position / form).

[0032] In the illustrated embodiment, sensor 20 includes a support member 110 fixed to cantilever 102 (or integrated as part of cantilever 102). In some embodiments, the support member 110 is constructed as a feature on a conventional CMOS circuit board, and sensor 20 may also be constructed within that conventional CMOS circuit board. Figure 5 and 6 As shown, one end 120 of the cantilever 102 near the support 110 is connected to or forms part of the support 110, while the relatively distal end 122 of the cantilever 102 is suspended and / or independent relative to any adjacent substrate or structure, thereby allowing the end 122 to move relative to the fixed end 120. In the illustrated embodiment, the end 122 is located near the latch or locking pawl 130. For example, the latch 130 has an end 132 coupled to or formed as part of the support member 134. When the cantilever 102 is in an unactuated or non-responsive state ( Figure 1When the latch 130 is suspended and / or freestanding relative to the distal end 136, and is disposed adjacent to but not in contact with the end 122 of the cantilever 102. In the illustrated embodiment, the face 140 of the end 136 faces the face 142 of the end 122 of the cantilever 102. Faces 140 and 142 are configured to be parallel to each other and spaced apart from each other in the unactuated or non-reactive state. Figure 5 Surfaces 140 and 142 are angled such that at least a portion of surface 140 extends over at least a portion of surface 142 (e.g., surface 142 forms an acute angle relative to surface 144 of beam 106, and surface 140 forms a supplementary angle relative to surface 144 toward cantilever 102). Latch 130 is configured as a flexible latch such that movement of cantilever 102 in the direction indicated by arrow 150 causes surface 142 to contact surface 140, and causes latch 130 to move away from cantilever 102 in the direction indicated by arrow 152, thereby enabling cantilever 102 to move past end 136 of latch 130 in response to a temperature event.

[0033] like Figure 5 As shown, sensor 20 includes an activator element 70 such that during the manufacture, storage, and / or transport of indicator 10 (e.g., before indicator 10 is placed on a temperature-monitoring item), cantilever 102 does not move a sufficient distance in direction 150 so that latch 130 latches even if sensor 20 has been exposed to a temperature event. Figure 5 As shown, the activator element 70 includes a barrier 74 disposed near the cantilever 102 to restrict movement of the cantilever 102 in direction 150 when the sensor 20 experiences a temperature event. It should be understood that the barrier 74 may otherwise be located and / or positioned near the cantilever 102 to restrict and / or prevent the cantilever 102 from moving to a point where the sensor 20 is in an actuated position or state.

[0034] Sensor 20 and its cantilever structure 102 can be directly fabricated on an integrated circuit substrate (e.g., a CMOS wafer), and other electronics of indicator 10 can also be fabricated on this integrated circuit substrate (e.g., RFID circuit 32, antenna 36, ​​etc.). Alternatively, sensor 20 and its cantilever structure 102 can be fabricated on a separate substrate, which is then electrically coupled or bonded to another substrate. It is readily understood that the cantilever structure 102 of sensor 20 is compatible with post-CMOS processes, and this process can be accomplished in a very small area even if there are multiple cantilevers 102 in sensor 20. It should also be understood that structures other than cantilever beams can be used, provided that relevant environmental parameters can be responded to by closing and / or opening electrical contacts.

[0035] In the illustrated embodiment, different materials are selected for beams 104 and 106 such that cantilever structure 102 bends or deflects in direction 150 in response to relevant environmental parameters (e.g., beams 104 and 106 each contain materials with different coefficients of thermal expansion). Figure 5 ).like Figure 5 and 6 As shown, the distal end 122 of beam 106 bridges gap 108 to connect to the distal end 160 of beam 104. As described above, the individual response of cantilever structure 102 to relevant environmental parameters may be referred to as a dual piezoelectric crystal in the discussion below, although it should be understood that a strictly dual piezoelectric crystal cantilever structure 102 is not necessary (e.g., cantilever structure 102 does not necessarily require two movable beams 104 and 106; instead, structure 102 may have a single movable beam or two or more movable beams). Sensor 20 can be configured to sense a variety of different environmental parameters that the RFID module or tag 30 may be subjected to (e.g., temperature, humidity / humidity, electromagnetic radiation, nuclear particle radiation, chemicals, biological agents, etc.). This capability can be achieved by using suitable materials to form the cantilever structure 102 of sensing element 100, as will be understood from the discussion below.

[0036] As previously described, the beams 104 and 106, made of different materials, exhibit inconsistent expansion / contraction (elongation / shrinkage) responses to relevant parameters, causing the cantilever structure 102 to bend in direction 150. This is because, under certain environmental conditions (e.g., threshold temperature or time-temperature parameters), beam 106 elongates significantly more than beam 104 or contracts significantly less than beam 104. Due to the side-by-side arrangement of beams 104 and 106 and their connection at their distal ends 160 and 122, respectively, the deflection of the cantilever structure 102 is in the direction of the plane containing the cantilever structure 102 and its beams 104 and 106. Because beams 104 and 106 are side-by-side and parallel, the gap 108 defined by and between beams 104 and 106 is constructed to have a uniform width along the length of beams 104 and 106. The presence of gap 108 causes beams 104 and 106 to not be in direct contact with each other for most of their length, with only the distal end 122 of beam 106 bridging gap 108 and connecting to the distal end 160 of beam 104. Therefore, the effective length portions of beams 104 and 106 that generate the double piezoelectric crystal effect do not directly contact or interact with each other.

[0037] According to some embodiments of this disclosure, sensor 20 is a MEMS device that functions as a switch (i.e., has detection circuitry 24) in response to one or more environmental parameters of the environment surrounding indicator 10. For example, in some embodiments, detection circuitry 24 may be configured as part of cantilever 102 (or directly on cantilever 102). For example, in some embodiments, beam 106 (and its distal end 122) and locking pawl 130 are conductive and function as a switch when in contact with each other. In this embodiment, support members 110 and 134 are also at least partially conductive to act as contacts of detection circuitry 24. In some embodiments, cantilever 102 and / or locking pawl 130 may have an outer layer of conductive material and / or deposited conductive traces, which also enables cantilever 102 and locking pawl 130 to function as a switch.

[0038] As mentioned above, Figure 5 The indicator 10 is shown in a non-responsive and inactive state (i.e., before field setup (e.g., by removing activator element 70)). In the example where the indicator 10 is used as a temperature sensor, if a temperature event or condition causes beam 106 to expand more than beam 104, this expansion would typically cause cantilever 102 to move in direction 150. However, before the activator element 70 is removed, the activator element 70 prevents and / or restricts the movement of cantilever 102 in direction 150, thereby preventing the cantilever from engaging the locking pawl 130. Therefore, before the activator element 70 is removed, the indicator 10 can experience a temperature event that would cause actuation or activation of sensor 20 without triggering the indicator 10.

[0039] After the activator element 70 is removed, the indicator 10 is in a reactive state (i.e., capable of being actuated in response to a temperature event). For example, in this embodiment, in response to experiencing a temperature event, the cantilever 102 moves in direction 150, such as... Figure 6 As shown. In this embodiment, the locking pawl 130 is configured such that the force applied to the locking pawl (e.g., the contact surface 140 of face 142) by the cantilever 102 in direction 150, generated by the movement of the cantilever 102 in direction 152, causes the locking pawl 130 to move in direction 152, thereby allowing the cantilever 102 to move past the end 136 of the locking pawl 130. Figure 6 As shown, after the cantilever 102 has moved past the end 136 of the locking pawl 130, the locking pawl 130 returns to its original position / orientation (e.g., moving in the opposite direction to direction 152). Therefore, once the locking pawl 130 returns to its initial position, it prevents the cantilever 102 from returning to its initial or non-responsive position, thereby causing irreversible actuation of the indicator 10.

[0040] Figure 7A schematic diagram of an embodiment of the activator element 70 according to this disclosure is shown. In the illustrated embodiment, the barrier 74 is anchored and / or coupled to the substrate 200 of the sensor 20. For example, in some embodiments, due to the miniature size of the cantilever 102 and the small volume of the overall indicator 10, the barrier 74 is also miniature and is manufactured using the same MEMS fabrication technology used to form the sensor 20. Figure 7 The image shows a portion of the cantilever 102 adjacent to the barrier 74. This is for ease of connection. Figure 5 and Figure 6 Explanation and description of the operation of sensor 20, in Figure 5 and Figure 6 The various components associated with activator element 70 are not shown. Figure 7 In this configuration, the barrier 74 is configured to separate from the substrate 200 at its proximal end 202 relative to the substrate 200. For example, since the cantilever 102 can move in response to a temperature event, if the temperature event would cause the cantilever 102 to move to an actuated state, the cantilever 102 will first contact the barrier 74, thereby limiting and preventing the movement of the cantilever 102, which would otherwise cause the cantilever 102 to engage the pawl 130. Figure 5 and 6 Therefore, the barrier 74 is attached to the substrate 200 near the end 122 of the cantilever 102 and has sufficient strength to withstand the momentum of the cantilever 102, which is generated by the potential movement of the cantilever 102 due to a temperature event.

[0041] exist Figure 7 In the illustrated embodiment, the block 74 includes an enlarged distal end 204 (remote to the proximal end 202) attached to the retaining element 72 using an adhesive layer 206 and an intermediate portion 208 extending between the ends 202 and 204. Because the microsensor 20 is miniature, the distal end 204 is configured to have sufficient surface area for the adhesive layer 206 to remain attached to it, such that when the retaining element 72 is removed or pulled away from the sensor 20, the retaining element 72 pulls up the enlarged distal end 204, thereby causing a force to be applied to the proximal end 202 of the block 74 in a direction remote from the substrate 200, to detach the block 74 from the substrate 200. In the illustrated embodiment, the proximal end 202 is configured to have a smaller cross-sectional area than the distal end 204, resulting in a smaller surface area attached to the substrate 200 by the proximal end 202, so that the block 74 can detach from the substrate 200 when the retaining element 72 is removed from the indicator 10. In some embodiments, the proximal end 202 may be formed of a more brittle material than the other portions of the barrier 74, so that the proximal end 202 can separate from the substrate 200 in response to the removal of the retaining element 72. In one embodiment, the barrier 74 may be undercut at the proximal end 202 to weaken the connection between the barrier 74 and the substrate 200 at the proximal end 202.

[0042] Furthermore, the cantilever structure 102 may include additional layers / films, such as stress-compensating layers, to improve strain distribution within the cantilever structure 102 due to any processing. The scope of this disclosure also includes any one or both of the beams 104 and 106 of the cantilever structure 102 assembling to form patterned layers for repairing beams 104 and 106, including their response to sensed environmental parameters such as temperature, humidity, chemicals, electromagnetic and particle radiation, ultraviolet light, and / or other environmental conditions. Additionally, as described above, beam 106 may have an outer layer of conductive material, thereby functioning as a switch when contacting a conductor on the locking claw 130.

[0043] Therefore, embodiments of this disclosure use a small-footprint temperature indicator to achieve temperature and / or temperature event detection. This temperature indicator uses a mechanical sensing element 100 with a passive RFID tag that provides different readings depending on the state of the temperature switching circuit. Because the RFID tag is passive, the temperature indicator does not require a battery or other external power source. Furthermore, the temperature indicator is constructed such that once actuated (or subjected to a sufficiently large temperature event), it is irreversible. Additionally, the temperature indicator of this disclosure can be configured with one or more indicating mechanisms (e.g., a sensor 20 manufactured from an LCD panel may include liquid visible in a specific area of ​​the indicator 10 upon activation). Furthermore, various manufacturing processes can be used for the indicator 10 (e.g., any manufacturing process implementing one or more micromechanical layers having 1) electrically contactable conductive elements, and 2) responsive to temperature changes). Examples include micromachining and wafer bonding manufacturing methods for silicon, silica, ceramics, nickel, titanium and other conductors; LIGA-type manufacturing processes using electroplated metals (i.e., photolithography, electroplating and molding); and additive manufacturing methods such as inkjet dispensing, slurry screen printing and other deposition methods using liquid curing.

[0044] The terminology used herein is for illustrative purposes only and is not intended to limit the scope of this disclosure. As used herein, the singular indefinite articles “a”, “an”, and the definite article “the” also include the plural forms unless the context clearly indicates otherwise. It will also be understood that the terms “comprises” and / or “comprising” as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0045] All corresponding structures, materials, actions, and equivalents, as well as the means, steps, and functional elements in the following claims, are intended to include any structure, material, or action used to perform the function in conjunction with the elements protected by the specific claims. This specification of the disclosure is provided for illustrative purposes but is not intended to limit the disclosure to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The selection and description of embodiments are also intended to best explain the principles and practical application of this disclosure and to enable others skilled in the art to understand that various embodiments with various modifications are suitable for the intended particular purpose.

Claims

1. A temperature indicator, comprising: Microsensors, having: A cantilevered sensing element coupled to a support member, the sensing element having a first layer and a second layer, the first layer and the second layer defining a gap between them along at least a portion of their respective lengths, and wherein the first layer is coupled to a first distal end of the support member to a second distal end of the second layer relative to the support member, the first layer and the second layer having different coefficients of thermal expansion, the first distal end and the second distal end of the sensing element being configured to move from a first position to a second position in response to exposure to a temperature event. The detection circuit is configured to change from a first state to a second state in response to the movement of the sensing element from a first position to a second position, and to prevent the detection circuit from returning to the first state in response to the change to the second state. and A latching element that moves in a first direction in response to contact of a sensing element moving from a first position to a second position; A radio frequency identification (RFID) module coupled to a detection circuit, wherein the RFID module is configured to output a value indicating that the sensing element is in a second position; and An activator element is configured to hold a sensor element in a first position until the activator element is removed from the microsensor.

2. The temperature indicator according to claim 1, characterized in that, The latching element is configured to prevent the sensing element from returning to the first position after it has been moved to the second position.

3. The temperature indicator according to claim 1, characterized in that, Miniature sensors are integrated on a chip substrate.

4. The temperature indicator according to claim 1, characterized in that, Miniature sensors are integrated onto liquid crystal display (LCD) panels.

5. The temperature indicator according to claim 1, characterized in that, The miniature sensor is integrated on a roll-to-roll (R2R) substrate.

6. The temperature indicator according to claim 1, characterized in that, The activator element includes: a portion close to the sensing element; and One end is configured to receive a force applied thereto, which displaces the portion from a position close to the sensing element.

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