Temperature indicator

Abstract

A temperature indicator includes a compound including an ionic fluid disposed in contact with an absorbing medium at a first location. The detection circuit is coupled to the absorbing medium at a second location spaced apart from the first location. The communication circuit is coupled to the detection circuit and is configured to output a value indicative of an actuation state of the temperature indicator indicated by the detection circuit. In response to the temperature indicator being exposed to a temperature exceeding a temperature threshold, the compound migrates along the absorbent medium from the first location to the second location. The detection circuit is configured to indicate its actuation state based on the presence of the compound at the second position.

Description

Priority information

[0001] This application claims priority to U.S. Provisional Application No. 63 / 340,775, filed on May 11, 2022, and this application claims priority to U.S. Provisional Application No. 63 / 459,302, filed on April 14, 2023, both of which are incorporated herein by reference for all purposes. Technical Field

[0002] The present application relates generally to temperature indicators. Background of the Invention

[0003] During manufacturing, storage or transportation, many types of objects need to be monitored or tracked due to their temperature sensitivity or fragility. For example, certain types of objects may be susceptible to damage 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 the object has been exposed. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A complete and enabling disclosure of the present invention, including the best mode thereof, for one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0005] Figure 1 A schematic diagram showing an application of an embodiment of a temperature indicator according to the present invention;

[0006] Figure 2 A block diagram showing an embodiment of a temperature indicator according to the present invention;

[0007] Figure 3A is a schematic diagram showing a top view of an embodiment of a temperature indicator according to the present invention in an inactive and non-actuated state;

[0008] Figure 3B It shows that according to the present invention Figure 3A Schematic diagram of a side view of the temperature indicator shown, taken from Figure 3A Line 3B-3B;

[0009] Figure 4A is a schematic diagram showing the Figure 3A and 3B a top view of the illustrated embodiment of the temperature indicator in an activated and actuated state; and

[0010] Figure 4B It is shown that according to the present invention Figure 4A The line 4B-4B is intercepted Figure 4A Schematic diagram of a side view of a temperature indicator shown.

[0011] Corresponding reference characters indicate corresponding parts throughout the several views.The exemplifications set out herein illustrate exemplary embodiments of the invention, and these exemplifications are not to be construed as limiting the scope of the invention in any way. Detailed description

[0012] Reference will now be made in detail to the present embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. The detailed description uses numbers and letters to refer to features in the drawings. The same or similar names in the drawings and the description are used to refer to the same or similar parts of the present invention.

[0013] The purpose of providing the following description is to enable those skilled in the art to make and use the described embodiments to implement the present invention. However, various modifications, equivalents, variations and substitutes are apparent to those skilled in the art. Any and all such modifications, variations, equivalents and substitutes are intended to fall within the scope of the present invention.

[0014] The word "exemplary" as used herein means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, unless otherwise noted, all embodiments described herein should be considered exemplary.

[0015] For the purposes of the following description, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and their derivatives shall relate to the orientation of the disclosed content in the accompanying drawings. However, it should be understood that the present invention may take various alternative variations unless expressly specified to the contrary. It should also be understood that the specific devices shown in the drawings and described in the following specification are merely exemplary embodiments of the present invention. Therefore, specific dimensions and other physical characteristics related to the embodiments disclosed herein should not be considered limiting.

[0016] As used herein, the terms “first” and “second” are used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of the components.

[0017] The singular definite and indefinite articles "a", "an" and "the" include plural forms unless the context clearly dictates otherwise.

[0018] The present invention generally relates to devices and techniques for temperature detection and indication. According to one embodiment, a temperature indicator includes an absorption medium and a compound, the compound including an ionic fluid disposed within a substance. When the temperature indicator is in an activated state, the compound contacts the absorption medium at a first position, and the substance is meltable at a temperature threshold. The temperature indicator also includes a detection circuit coupled to the absorption medium at a second position spaced apart from the first position, and a communication circuit coupled to the detection circuit. The communication circuit is configured to output a value indicating an actuation state of the temperature indicator indicated by the detection circuit. In response to the temperature indicator being exposed to a temperature exceeding the temperature threshold, the compound melts, is absorbed by the absorption medium, and migrates from the first position to the second position along the absorption medium. The detection circuit is configured to indicate the actuation state based on the presence of the compound at the second position. Therefore, in operation, in response to the temperature indicator being exposed to a temperature exceeding the temperature threshold, the substance of the compound melts, thereby causing the compound to be absorbed by the absorption medium. The compound migrates along or through the absorption medium to the second position where the detection circuit is located (e.g., by capillary action or other means). In response to the compound reaching or contacting the detection circuit, the ionic fluid within the compound causes a change in level or resistance or conductivity through the detection circuit. The change in resistance or conductivity level via the detection circuit is used to indicate an actuation state of the temperature indicator. The indicator also includes a wireless communication module coupled to the detection circuit, the wireless communication module being configured to output a value indicating the actuation state of the temperature indicator. The temperature indicator also includes an activator element, the activator element being configured to maintain the temperature indicator in an inactive or non-reactive state until the activator element is removed from the temperature indicator.

[0019] Many types of objects require that the temperature of the object be monitored during storage, transportation, or use (i.e., cold chain). For example, some types of objects, such as food or medication, may be susceptible to spoilage or failure if exposed to excessively high temperatures for extended periods of time. The duration or threshold of a temperature excursion (i.e., a "time-temperature" variable) is often more important than a non-duration focused or real-time temperature reading. Therefore, for quality control purposes and / or general monitoring of transportation / use conditions, it is necessary to determine and / or verify the temperature conditions to which an object has been exposed.

[0020] Reference is now made to the accompanying drawings, in which in particular Figure 1 In the same figures, the same elements are indicated. Figure 1 is an exemplary diagram of a temperature indicator 10 in which an illustrative embodiment of the present invention may be implemented. Figure 1In the embodiment, the indicator 10 is a portable device configured to be secured to or disposed within a transport container 11 that contains an object to be monitored for temperature events associated therewith (or the object of interest itself). Embodiments of the temperature indicator 10 monitor whether an object has been exposed to a particular temperature or environment during manufacturing, storage, and / or transportation. In an exemplary embodiment, the temperature indicator 10 may be secured to the transport container 11 using, for example, an adhesive material, permanent or temporary fasteners, or a variety of different types of attachment devices. The transport container 11 may include a container in which the monitored object is loosely placed, or may include a container for the monitored object itself. It should be understood that Figure 1 This is merely exemplary and is not intended to assert or imply any limitation with regard to the environments in which different embodiments may be implemented.

[0021] 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 a temperature event relative to the indicator 10 (e.g., to detect when the indicator 10 (and, accordingly, the container to which the indicator 10 is associated) has been subjected to a particular ambient temperature and / or ambient temperature for a particular duration). In an exemplary embodiment, the housing 12 is constructed and / or formed of a transparent or translucent material having a masking label 16 located on a front side thereof or affixed thereto. In an exemplary embodiment, 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 an exemplary embodiment, in response to the indicator 10 being subjected to a particular temperature, the detection component 14 causes a visual indication to be displayed within or through the 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 may be used to provide a visual indication that the temperature indicator 10 has been placed in an activated state, indicating that the temperature indicator 10 has experienced a certain temperature level that exceeds a certain temperature threshold. It should also be understood that the housing 12 may be configured and / or manufactured from other materials (e.g., an opaque material having one or more windows 18 formed therein). In an exemplary embodiment, the housing 12 may be configured without the windows 18. For example, as will be described in more detail below, the temperature indicator 10 may be configured to provide a visual and / or non-visual indication (e.g., by using a wireless signal) of whether the temperature indicator 10 has experienced a temperature condition or event.

[0022] Figure 2 FIG. 1 is a block diagram showing and illustrating an embodiment of a temperature indicator 10 according to an embodiment of the present invention. Figure 2, the temperature indicator 10 includes a temperature sensing assembly 14 including a sensing circuit 20. The temperature indicator 10 also includes a wireless communication module 22. In an exemplary embodiment, the sensing circuit 20 is electrically and / or communicatively coupled to the communication module 22. The sensing circuit 20 may include one or more switching elements, traces, contacts, and / or circuits that are responsive to detecting or indicating a change in an actuation condition or state of the temperature indicator 10. For example, in an exemplary embodiment, the sensing circuit 20 may include one or more switching elements, traces, contacts, and / or circuits that may become or form a conductive path or become non-conductive (e.g., a change in impedance or resistance, from an open circuit state to a closed circuit state, vice versa, etc.) in response to being subjected to a temperature event (e.g., a temperature exceeding a certain temperature-time threshold or a temperature-time event). In an exemplary embodiment, the detection circuit 20 may include one or more switching elements, traces, contacts, and / or circuits by which a resistance value may be measured to determine whether the temperature indicator 10 has been subjected to or experienced a temperature event (e.g., a temperature or temperature-time event exceeding a certain threshold). In an exemplary embodiment, the detection circuit 20 may be (permanently or removably) affixed to a printed circuit board and / or otherwise permanently or removably connected to an electronic circuit (e.g., such as a removable box) such that, in response to receiving and / or detecting a temperature condition of sufficient magnitude and / or exceeding a certain threshold, the detection circuit 20 provides an electronic signal / indication of such an event.

[0023] The wireless communication module 22 is configured to wirelessly transmit information associated with the state of the detection circuit 20 indicating the actuation state of the temperature indicator 10 (e.g., based on the state of the detection circuit 20 and / or a value measured or detected by the detection circuit 20). For example, in an exemplary embodiment, the wireless communication module 22 includes an RFID module 30. In an exemplary embodiment, the RFID module 30 includes a passive RFID module 30 (e.g., a passive RFID tag) having an RFID integrated circuit (chip) or circuit 32 (e.g., disposed on or as part of a printed circuit board, such as an RFID tag) and a memory 34, and an antenna 36. As a passive RFID module 30, the indicator 10 does not contain a battery (e.g., powered by a reader 40 (e.g., an RFID reader 40)), thereby forming a battery-free temperature indicator 10. For example, when the module 30 encounters radio waves from the reader 40, the antenna 36 forms a magnetic field, thereby powering the module 30 to excite the circuit 32. Once powered / activated, the module 30 can output / transmit information encoded in the memory 34 (e.g., using a communication protocol such as near field communication (NFC), ISO-18000-3, ISO 18000-6, UHF Gen2, ISO-15693, etc.). However, it should be understood that in an exemplary embodiment, 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 based on a programmed or event trigger. One embodiment of a passive RFID tag is a flexible circuit RFID in roll form. In flexible circuit RFIDs, the chip and antenna are embedded into a thin substrate of 100 to 200 nm using, for example, polyvinyl chloride (PVC), polyethylene terephthalate (PET), phenolic plastic, polyester, styrene, or paper by copper etching or hot stamping. One process for RFID manufacturing is screen printing using conductive inks containing copper, nickel, or carbon. An example of a commercially available flexible circuit passive RFID tag product that may have hundreds or even thousands of tags in a roll is the Smartrac™ product from Avery Dennison.

[0024] It should also be understood that the wireless communication module 22 may 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 natively 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 receiving a specific level and / or magnitude of a temperature event, the temperature indicator 10 functions as a passive temperature sensor / indicator, which may be used as part of an electronic signal or circuit. In an exemplary embodiment, the temperature sensing capability / function of the temperature indicator 10 of the present invention does not require power in a monitoring state.

[0025] In the illustrated embodiment, the memory 34 includes at least two different stored and / or encoded values ​​42 and 44. For example, the value 42 may correspond to a value outputted / transmitted by the module 30 when the detection circuit 20 detects an actuated state of the temperature indicator 10, and the value 44 may correspond to a value outputted / transmitted by the module 30 when the detection circuit 20 detects a non-actuated state of the temperature indicator 10. As an example, the value 44 may represent an RFID tag identification (ID) number that indicates a non-actuated state of the temperature indicator 10, and the ID number of the RFID tag may have an additional character (e.g., "0") placed at the end thereof. The value 42 may represent an RFID ID number that indicates an activated state of the temperature indicator 10, and the ID number of the RFID tag may have an additional character (e.g., "1") at the end thereof that is different from the additional character carried by the value 44. In the illustrated embodiment, the RFID module 30 (e.g., the circuit 32) is electrically and / or communicatively coupled to the detection circuit 20, and may detect or be provided with data indicating an actuated state determined or identified by the detection circuit 20. Thus, for example, the detection circuit 20 may initially be in or detect an unactivated state of the temperature indicator 10. Thus, if powered on / activated, the module 30 would transmit the value 44 to the reader 40. If the temperature indicator 10 is subjected to a temperature event, a change in the state or measured or detected value of the detection circuit 20 (or a change in the measured or detected value) would cause the detection circuit 20 to indicate an activated state of the temperature indicator 10. Thus, if powered on now (e.g., after a temperature event), the module 30 would instead transmit the value 42 to the reader 40. Thus, when the temperature indicator 10 does not contain or require any internal power source (e.g., a battery), embodiments of the present invention enable the indicator 10 to use an electronic indicator (e.g., an RFID or other type of wireless reader) to monitor a sensitive product / object to which it is attached for potential damage caused by temperature changes.

[0026] In an exemplary embodiment, the wireless communication module 22 includes an NFC module 50 in addition to or as an alternative to the RFID module 30. Similar to the RFID module 30, in an exemplary embodiment, the NFC module 50 includes a passive NFC module 50 having an NFC integrated circuit (chip) or circuit 52 (e.g., arranged on a printed circuit board or as part of a printed circuit board, such as an NFC tag) and a memory 54, as well as an antenna 56. As a passive NFC module 50, the indicator 10 does not contain a battery (e.g., powered by the reader 40), thereby forming a battery-free temperature indicator 10. For example, when the NFC module 50 encounters radio waves from the reader 40, the antenna 56 forms a magnetic field, thereby powering the NFC module 50 to activate the circuit 52. Once powered / activated, the NFC module 50 can output / transmit information encoded in the memory 54. In the illustrated embodiment, the memory 54 includes at least two different stored and / or encoded values ​​62 and 64. For example, value 62 may correspond to a value output / sent by the NFC module 50 when the detection circuit 20 detects or indicates the startup state of the temperature indicator 10 , and value 64 may correspond to a value output / sent by the NFC module 50 when the detection circuit 20 detects or indicates the startup state of the temperature indicator 10 .

[0027] The present invention may include computer program instructions (e.g., stored in a computer-readable storage medium (or multiple media) (e.g., memory 34 and / or 54)) at any possible level of technical detail integration for causing a processor to perform aspects of the present invention. The computer-readable program instructions described herein may be downloaded to a corresponding computing / processing device (e.g., communication module 22, RFID module 30, and / or NFC module 50). The computer-readable program instructions for performing the operations of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, configuration data of an integrated circuit, or source code or object code written in any combination of one or more programming languages. In an exemplary embodiment, an electronic circuit (e.g., circuit 32 and / or 52) including, for example, a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA) may be executed by utilizing the state information of the computer-readable program instructions to personalize the electronic circuit to execute computer-readable program instructions so as to perform aspects of the present invention. Various aspects of the present invention are described herein with reference to diagrams and / or block diagrams of methods and / or devices according to embodiments of the present invention. It will be understood that each frame of the diagram and / or block diagram and the combination of frames in the diagram and / or block diagram can represent a module, a code segment or a code portion, which can be implemented by computer-readable program instructions. These computer-readable program instructions can be provided to a processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor create a device for implementing the function / action specified in one or more frames of the diagram and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium, which can instruct a computing device, a programmable data processing device and / or other devices to operate in a specific manner, so that the computer-readable storage medium in which the instructions are stored includes a manufactured product, which includes instructions for implementing various aspects of the function / action specified in one or more frames of the diagram and / or block diagram. The detection circuit 20, the wireless communication module 22, the RFID module 30 and / or the NFC module 50 can be implemented in any suitable manner using known technologies, which can be hardware-based, software-based or a combination of the two. For example, the detection circuit 20, the wireless communication module 22, the RFID module 30 and / or the NFC module 50 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, concentrated in a single integrated circuit or distributed in different chips in a data processing system) for performing the various functions described herein. As will be appreciated by those skilled in the art, some aspects of the present invention may be embodied as a system, method or computer program product.Thus, some aspects of the present invention may take the form of a hardware embodiment, a software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, which are generally referred to herein as a "circuit," "module" or "system."

[0028] refer to Figures 3A-4B , Figure 3A is a schematic top view of an exemplary embodiment of a temperature indicator 10 according to the present invention in a non-activated and non-actuated state, Figure 3B According to the present invention Figure 3A A schematic side view of an exemplary temperature indicator 10 in a non-activated and non-actuated state, Figure 4A According to the present invention Figure 3A and 3B A schematic top view of an exemplary embodiment of a temperature indicator 10 in an activated and actuated state, Figure 4B According to the present invention Figure 3A , 3B 4A is a schematic side view of an exemplary temperature indicator 10 in an activated and actuated state. Figures 3A-4B In the present invention, for the convenience of description and explanation, the temperature indicator 10 is described as having no housing 12 ( Figure 1 ).

[0029] In the illustrated embodiment, the temperature indicator 10 includes a substrate 100 to which the detection assembly 14 is fixed. For example, in the illustrated embodiment, the detection circuit 20 and the communication module 22 are fixed, bonded, or otherwise fixed to the top side 102 of the substrate 100. The bottom side 104 of the substrate 100 can be fixed to the interior ( Figure 1 ), or it may itself form part of the housing 12 ( Figure 1 ). In an exemplary embodiment, substrate 100 is configured to be non-absorbent at least in certain regions or portions thereof. For example, in an exemplary embodiment, substrate 100 includes a paper-based layer having a plastic moisture barrier or coating on its top side 102. The moisture barrier or coating may cover the entire paper-based layer, or may be applied only on the top surface 102 of substrate 100 (or even on a localized region of the top surface 102). However, it should be understood that substrate 100 may be formed of other non-absorbent materials.

[0030] In the illustrated embodiment, the temperature indicator 10 includes an absorbent medium 110 disposed on or otherwise secured to the top side 102 of the substrate 100. In the exemplary embodiment, the absorbent medium 110 includes chromatography paper or filter paper; however, it should be understood that other types of absorbent materials may also be used for the absorbent medium 110. In the exemplary embodiment, the absorbent medium 110 includes a porous or fibrous material (or micromaterial) that provides a constant rate of capillary migration of a fluid therethrough (e.g., similar to a sponge). In the illustrated embodiment, the absorbent medium 110 is secured to the substrate 100 using a thermal bonding technique; however, it should be understood that the absorbent medium 110 may be secured to the substrate 100 using other techniques.

[0031] In the exemplary embodiment, the detection circuit 20 includes conductive terminals 120 and 122. In the illustrated embodiment, the conductive terminals 120 and 122 are disposed and / or otherwise coupled to the top side 102 of the substrate 100. In addition, the conductive terminals 120 and 122 are disposed to contact or couple to the absorptive medium 110 at or near a location 130 relative to the absorptive medium 110. In the illustrated embodiment, the conductive terminals 120 and 122 are disposed between the absorptive medium 110 and the top surface 102 of the substrate 100. However, it should be understood that the conductive terminals 120 and 122 may additionally or alternatively be coupled to the top side 132 of the absorptive medium 110. In the exemplary embodiment, the conductive terminal 120 is disposed in a spaced relationship relative to the conductive terminal 122 such that the absorptive medium 110 forms a bridge extending between the conductive terminals 120 and 122. In other words, a portion of the absorptive medium 110 in contact with the conductive terminal 120 is spaced apart from another portion of the absorptive medium 110 in contact with the conductive terminal 122. In the illustrated embodiment, the absorptive medium 110 is depicted as being spaced apart from the top side 102 of the substrate 100 at a location 130 extending between the conductive terminals 120 and 122 (e.g., forming a gap between a bottom side 134 of the absorptive medium 110 and the top side 102 of the substrate 100); however, it should be understood that the bottom side 134 of the absorptive medium 110 may also be in contact with the top side 102 of the substrate. In an exemplary embodiment, the conductive terminals 120 and 122 may be formed of copper or aluminum traces, or may be formed of other conductive materials.

[0032] In the illustrated embodiment, the detection circuit 20 is electrically and / or communicatively coupled to the communication module 22. For example, in the illustrated embodiment, for ease of description and illustration, the communication module 22 is depicted as including the RFID module 30 and the corresponding RFID circuit 32 and the antenna 36; however, it should be understood that the communication module 22 may additionally or alternatively include the NFC module 50 (FIG. 3) and the corresponding NFC circuit 52 (FIG. 3) and the antenna 56 (FIG. 3). Therefore, in the exemplary embodiment, the conductive terminals 120 and 122 are electrically coupled to the RFID circuit 32. As will be further described below, the detection circuit 20 indicates the actuation state of the temperature indicator 10 via the conductive terminals 120 and 122 based on the resistance or resistance measurement level / reading between the conductive terminals 120 and 122 measured on the absorptive medium 110 extending between the conductive terminals 120 and 122. In an exemplary embodiment, the RFID circuit 32 can function as a multimeter, for example, measuring or otherwise detecting the resistance between the conductive terminals 120 and 122 measured across the absorptive medium 110 extending between the conductive terminals 120 and 122. In the illustrated embodiment, the RFID circuit 32 (or RFID chip) is electrically coupled to the antenna 36. In at least one embodiment, the RFID circuit 32 can include an RFID chip sold by NXP with part number SL3S1013. In at least another embodiment, the NFC circuit (FIG. 3) can include an NFC chip manufactured by EM Microelectronics of Marin, Switzerland with part number EM4425.

[0033] In the exemplary embodiment, the temperature indicator 10 includes a compound 140 disposed on the top side 102 of the substrate 100 at a position 142 relative to the absorbent medium 110. In the exemplary embodiment, the position 142 is spaced apart from the position 130 such that there is a span S of the absorbent medium 110 extending from the position 130 to the position 142. In the illustrated embodiment, the absorbent medium 110 extends in a longitudinal direction extending proximate to a side 144 of the substrate 100. In the illustrated embodiment, as shown in FIG. Figure 3A and 3BAs shown, the temperature indicator 10 includes an activator element 150, which maintains the temperature indicator 10 in an inactive (or non-reactive) state until it is removed from the temperature indicator 10 (i.e., cannot be converted from the inactive state to the activated state, wherein the inactive state refers to the state of the temperature indicator before experiencing or being subjected to a temperature event above a certain threshold, and the activated state refers to the state of the temperature indicator 10 having been subjected to a temperature event at or above the threshold). For example, during the process of shipping the temperature indicator 10 to the end user (or otherwise), the temperature indicator 10 may be affected by a temperature event, which is detected by the temperature indicator 10 and causes the temperature indicator 10 to be converted to the activated state (i.e., indicating the receipt of the temperature event). Even if the temperature indicator 10 experiences a temperature event, the activator element 150 prevents the temperature indicator 10 from being converted from the inactive state to the activated state. Removing the activator element 150 from the temperature indicator 10 places the temperature indicator 10 in an activated state or sensing mode (i.e., able to detect a temperature event and convert to an activated state to indicate the receipt of the temperature event). For example, in an exemplary embodiment, activator element 150 includes a thin plastic material disposed between compound 140 and absorbent medium 110 at location 142, thereby preventing contact between compound 140 and absorbent medium 110. Activator element 150 can be pulled or displaced in direction 152 from between compound 140 and absorbent medium 110 (e.g., caused by a force applied thereto by an end user in direction 152), which then places temperature indicator 10 in an activated state or sensing state such that compound 140 is in contact with absorbent medium 110 at location 142 ( Figure 4A and 4B ). Figures 3A-4B Although not explicitly shown, in the exemplary embodiment, the housing 12 ( Figure 1 ) may include an upper wall or member fixed to the base 100 (or a bottom wall ( Figure 1 )), which causes a compressive force to be applied between the absorptive medium 110 and the compound 140, such that in response to the removal of the activator element 150, the compressive force causes the absorptive medium 110 to be placed in contact with the compound 140 at the location 142 ( Figure 1 In an exemplary embodiment, a portion of the activator element 150 may extend to the housing 12 ( Figure 1 ) (e.g., extending through an opening or slit formed in an outer wall of the housing ( Figure 1 )) so that an end user of the temperature indicator 10 can grasp the activator element 150 and remove it from the temperature indicator 10, thereby placing the temperature indicator 10 in an activated or sensing state.

[0034] In an exemplary embodiment, compound 140 includes a mixture of a meltable substance and an ionic fluid. Meltable substances include substances having a melting point at a temperature of interest (e.g., the desired actuation temperature of temperature indicator 10). Such meltable substances can be found in products identified as WarmMark obtained from SpotSee in Dallas, Texas. Ionic fluids include fluids having conductive properties that can be incorporated into meltable substances. For example, in an exemplary embodiment, the ionic fluid includes a substance that enhances or initiates electrical conduction. In an exemplary embodiment, compound 140 is disposed on top side 102 of substrate at position 142 and adhered to top side 102 of substrate 100 at position 142. For example, the meltable substance may include material properties that cause compound 140 to adhere to top side 102 of substrate 100. It should also be understood that compound 140 may also be within a reservoir or other type of retaining element (not shown) to hold compound 140 at position 142. In other exemplary embodiments, a portion of the material for the absorptive medium 110 may be saturated with the compound 140 and, after curing, placed in the location 142 between the activator element 150 and the top side 102 of the substrate 100. In operation, the compound 140 remains solid and is not absorbed into the absorptive medium 110 until the temperature indicator 10 is exposed to a temperature exceeding a certain temperature threshold (e.g., a temperature that causes the meltable substance to melt).

[0035] refer to Figure 4A and 4BIn an exemplary embodiment, the ionic fluid is miscible in the meltable substance such that in response to the temperature indicator 10 being subjected to a temperature event (e.g., a temperature exceeding the melting temperature of the meltable substance of the compound 140), the compound 140 will migrate through and / or along the absorptive medium 110 from the location 142 toward the location 130 (e.g., in the direction 160). For example, in response to the temperature indicator 10 being subjected to a temperature event exceeding the melting temperature of the meltable substance of the compound 140, the compound 140 will melt and will be absorbed by the absorptive medium 110 and migrate from the location 142 toward the location 130. After a period of time after the temperature excursion exceeds the melting temperature of the meltable substance of the compound 140, the compound 140 within the absorptive medium 110 will reach the conductive terminals 120 and 122 and extend within the absorptive medium 110 from the conductive terminal 120 to the conductive terminal 122. The conductive properties of the ionic fluid within the compound 140 change the level of resistance between the conductive terminals 120 and 122 measured through the absorptive medium 110. For example, in an exemplary embodiment, the presence of compound 140 in absorption medium 110 extending between and contacting each of conductive terminals 120 and 122 results in a reduced resistance between conductive terminals 120 and 122 as compared to the resistance between conductive terminals 120 and 122 measured across absorption medium 110 in the absence of ionic fluid in absorption medium 110 between conductive terminals 120 and 122.

[0036] Thus, in operation, when the compound 140 is not in contact with the conductive terminals 120 and 122, a higher resistance will be measured or indicated between the conductive terminals 120 and 122 than when the compound 140 is in contact with the conductive terminals 120 and 122. Thus, when the compound 140 is not in contact with the conductive terminals 120 and 122 and the communication module 22 is powered on, the higher resistance measured or indicated between the conductive terminals (e.g., read or determined by the RFID circuit 32 and / or the NFC circuit 52 (FIG. 3)) is an indication of the unactivated state of the temperature indicator 10. Additionally, when the compound 140 is in contact with the conductive terminals 120 and 122 and the communication module 22 is powered on, the lower resistance measured or indicated between the conductive terminals (e.g., read or determined by the RFID circuit 32 and / or the NFC circuit 52 (FIG. 3)) is an indication of the activated state of the temperature indicator 10. In an exemplary embodiment, the compound 140 may also include a dye to enable or enhance visibility of the compound at the location 130 (e.g., through the window 18 ( Figure 1 )).

[0037] In an exemplary embodiment, the temperature indicator 10 can be configured to correspond to a desired activation time-temperature threshold. For example, the distance between the position 142 and the position 130 can be varied, different materials can be used for the absorption medium 110, resulting in different rates of capillary migration of the compound 140 through the absorption medium 110, the meltable material of the compound 140 can be changed to accommodate different melting temperatures of the meltable material, the ionic fluid of the compound 140 can be changed, etc., or any combination of these factors.

[0038] In an exemplary embodiment, myristicin and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF4) are used as ionic liquids for compound 140. A 20% BMI.BF4 mixture is prepared by dissolving 20 grams of BMI.BF4 in 80 grams of myristicin. A 5 cm x 1 cm filter paper strip is immersed in the solution, and the electrodes of a multimeter are connected to the top of the paper. The solution is raised by capillary action at a temperature of 17°C. When the solution contacts the electrodes of the multimeter, the resistance recorded on the multimeter drops from at least 20 megohms to less than 2 megohms.

[0039] In another example, myristicinonitrile and 1-methyl-3-octylimidazolium hexafluorophosphate (OMIM PF6) were used for the ionic liquid of compound 140. A mixture of 20% OMIM PF6 was prepared by dissolving 20 grams of OMIM PF6 in 80 grams of myristicinonitrile. A 5 cm x 1 cm strip of filter paper was immersed in the solution. The electrodes of an ohmmeter were attached to the top of the paper. The solution was allowed to rise at 18°C ​​by capillary action. When the solution came into contact with the electrodes, the resistance recorded on the meter dropped from at least 20 megohms to less than 2 megohms.

[0040] Thus, embodiments of the present invention provide a temperature indicator utilizing a mixture or compound that includes an ionic fluid combined with a meltable substance such that when the compound reaches a temperature threshold that causes the meltable substance to melt, the compound is absorbed into an absorptive medium and begins to migrate along the absorptive medium (e.g., by capillary action). In response to the compound reaching a pair of conductive terminals disposed in contact with the absorptive medium, the ionic fluid within the compound changes a resistance level between the conductive terminals that can be measured across the absorptive medium. The resistance level that can be measured between the conductive terminals across the absorptive medium provides an indication of an activated state of the temperature indicator.

[0041] Although specific features of various embodiments may be shown in some drawings but not in other drawings, this is only for convenience of description. According to the principles of the present invention, any feature of a drawing may be referenced and / or claimed in combination with any feature of any other drawing.

[0042] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any combined method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims, these other examples are intended to be within the scope of the claims.

[0043] Although the present invention has been described as having an exemplary design, the present invention may be further modified within the scope of the present invention. Therefore, the application is intended to cover any variation, use or adaptation of the present invention using its general principles. In addition, the application is intended to cover such some deviations from the present invention, which belong to the known or customary practices of the field to which the present invention belongs, and fall within the scope of the appended claims.

Claims

1. A temperature indicator comprising: Absorption medium; comprising an ionic fluid compound disposed within a substance, the compound contacting an absorptive medium at a first location when the temperature indicator is in an activated state, the substance being meltable at a temperature threshold; a detection circuit coupled to the absorptive medium at a second location spaced apart from the first location; and a communication circuit coupled to the detection circuit, wherein the communication circuit is configured to output a value indicative of an actuation state of a temperature indicator indicated by the detection circuit; and wherein the compound migrates from the first location to the second location along the absorptive medium in response to the temperature indicator being exposed to a temperature exceeding a temperature threshold, and wherein the detection circuit is configured to indicate the actuation state based on the presence of the compound at the second location. 2 . The temperature indicator according to claim 1 , further comprising an activator element configured to maintain the temperature indicator in an inactive state.

3. The temperature indicator according to claim 2, characterized in that Removal of the activator element places the temperature indicator in an activated state.

4. The temperature indicator of claim 2, wherein the activator element comprises: a first portion disposed between the compound and the absorption medium; and The second portion is configured to receive a force applied thereto to move the first portion out of a position between the compound and the absorbent medium.

5. The temperature indicator of claim 1, wherein the absorption medium comprises a chromatographic medium.

6. The temperature indicator of claim 1, wherein the detection circuit includes a first conductive terminal spaced apart from a second conductive terminal, the first and second conductive terminals being coupled to the absorptive medium. 7 . The temperature indicator of claim 6 , wherein the detection circuit is configured to determine a resistance between the first and second conductive terminals to determine the actuation state.

8. A temperature indicator comprising: Absorption medium; a compound comprising an ionic fluid disposed in contact with an absorption medium at a first location; a detection circuit including first and second conductive terminals spaced apart from one another and coupled to the absorptive medium spaced apart from the first location, the detection circuit being configured to indicate an actuation state of the temperature indicator based on a resistance measured between the first and second conductive terminals; and a communication circuit coupled to the detection circuit, wherein the communication circuit is configured to output a value indicative of an actuation state indicated by the detection circuit; and wherein, in response to the temperature indicator being exposed to a temperature exceeding a temperature threshold, the compound migrates along the absorptive medium from the first location toward the first and second conductive terminals, and in response to the compound contacting the first and second conductive terminals, the compound affects the resistance.

9. The temperature indicator of claim 8, further comprising an activator element configured to maintain the temperature indicator in an inactive state.

10. The temperature indicator according to claim 9, characterized in that Removing the activator element places the temperature indicator in an active state wherein the compound is in contact with the absorption medium.

11. The temperature indicator of claim 9, wherein the activator element comprises: a first portion disposed between the compound and the absorption medium in an inactive state; and The second portion is configured to receive a force applied thereto to move the first portion out of a position between the compound and the absorbent medium.

12. The temperature indicator of claim 8, wherein the absorption medium comprises a chromatographic medium.

13. The temperature indicator of claim 8, wherein the compound causes a reduction in electrical resistance in response to the compound contacting the first and second conductive terminals.

14. The temperature indicator according to claim 8, wherein The communication circuit includes at least one of a radio frequency identification (RFID) module or a near field communication (NFC) module.

15. A temperature indicator comprising: Absorption medium; a compound comprising an ionic fluid disposed in contact with an absorption medium at a first location; a detection circuit coupled to the absorptive medium spaced apart from the first location, the detection circuit configured to indicate an actuation state of the temperature indicator; and a communication circuit coupled to the detection circuit, wherein the communication circuit is configured to output a value indicative of the actuated state indicated by the detection circuit; and wherein in response to the temperature indicator being exposed to a temperature exceeding a temperature threshold, the compound migrates along the absorptive medium from the first location toward the detection circuit, and the detection circuit indicates an activation state in response to the compound contacting the detection circuit.

16. The temperature indicator of claim 15, further comprising an activation element removable from between the compound and the absorption medium to place the temperature indicator in an activated state wherein the compound is in contact with the absorption medium.

17. The temperature indicator of claim 15, wherein the absorption medium comprises a chromatographic medium.

18. The temperature indicator of claim 15, wherein the detection circuit includes a first conductive terminal spaced apart from a second conductive terminal, the first and second conductive terminals being coupled to the absorptive medium.

19. The temperature indicator of claim 18, wherein the detection circuit is configured to measure the resistance between the first and second conductive terminals.

20. The temperature indicator of claim 19, wherein the compound causes a reduction in electrical resistance when in contact with the first and second conductive terminals.

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