Systems and methods for detecting the status of a drug

Abstract

A sensing system for determining a compression spring condition is provided. The system can comprise capacitance plates located on the two opposite sides of a compression spring, a temperature sensor and at least one processing circuit. The processing circuit is configured to measure a capacitance between the capacitance plates, measure a temperature based on a signal output by the temperature sensor, and determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature. In some embodiments, a sensing system may be used to detect a status of a compression spring disposed on or within the drug delivery device, thereby determining a status of the drug delivery device. For example, a sensing system may be used to determine whether a drug delivery device has been activated, or whether the device has completed drug delivery.

Description

Technical Field

[0001] The present invention relates to systems and methods for detecting the state of a compression spring. More specifically, the present invention relates to systems and methods for detecting whether a compression spring used on or within a drug delivery device is in a compressed state or an extended state, and thereby inferring the state of the drug delivery device. Background Art

[0002] Drug delivery devices typically use compression springs to operate. When components of a drug delivery device move to a specific position or transition to a different configuration, such a spring can transition from a compressed state to an extended state, or from an extended state to a compressed state. For example, a spring can be used to drive a syringe assembly to pierce a user's skin, or to pump a drug after a needle has been inserted. A spring can also be used to retract the syringe assembly after use, or to extend a needle sheath surrounding an injection needle to reduce the likelihood of an accidental needle stick. Summary of the Invention

[0003] According to an exemplary embodiment of the present invention, there is provided a drug delivery device for determining the state of a compression spring of the drug delivery device. The sensing system includes: a first capacitor plate and a second capacitor plate configured such that the compression spring is located between at least a portion of the first capacitor plate and at least a portion of the second capacitor plate; a temperature sensor; and at least one processing circuit connected to the first capacitor plate, the second capacitor plate, and the temperature sensor. The at least one processing circuit is configured to: measure the capacitance between the first capacitor plate and the second capacitor plate, measure the temperature based on a signal output by the temperature sensor, and determine / judge whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

[0004] According to another embodiment of the present invention, there is provided an injection system including: a drug delivery device housing; a syringe assembly at least partially disposed within the drug delivery device housing, the syringe assembly including an injection needle and a liquid reservoir configured to hold a drug; a drive mechanism at least partially disposed within the drug delivery device housing and configured to dispense the drug from the syringe assembly via the injection needle after a user activation, the drive mechanism including a compression spring configured to transition from a compressed state to an extended state, or from an extended state to a compressed state, after the activation; and a sensing system including: a first capacitor plate and a second capacitor plate configured such that the compression spring is located between at least a portion of the first capacitor plate and at least a portion of the second capacitor plate; a temperature sensor; and at least one processing circuit configured to: measure the capacitance between the first capacitor plate and the second capacitor plate, and measure the temperature based on a signal output by the temperature sensor.

[0005] According to another embodiment of the present invention, there is provided a method for determining the state of a compression spring located between at least a portion of a first capacitor plate and at least a portion of a second capacitor plate, the method comprising: measuring a temperature using a temperature sensor; measuring a capacitance between the first capacitor plate and the second capacitor plate; and determining whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

[0006] Among other advantages, the disclosed methods, apparatuses, and systems provide a reliable and cost-effective way to determine whether a spring is in a compressed state or an extended state. In some embodiments, an exemplary advantage is that the disclosed methods, apparatuses, and systems can determine the state of the spring without physical contact with the spring (or any component in physical contact with the spring), as such physical contact may interfere with the operation of the spring. In some embodiments, another exemplary advantage is that the disclosed methods, apparatuses, and systems can be mounted on or integrated with a thin flexible sheet, which can be adhered to the outer surface of an existing drug delivery device, thereby providing sensing and communication capabilities for such existing or previously available devices in a low-cost manner without any changes to the internal components of such delivery devices. In some embodiments, another exemplary advantage of the disclosed methods, apparatuses, and systems is that by considering the ambient temperature (and / or the temperature of the sensing system or the sensed compression spring), the disclosed methods, apparatuses, and systems can detect whether the compression spring is in a compressed state or an extended state more accurately and reliably. Those of ordinary skill in the art will recognize other advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The above and other features and advantages of the present invention, and the manner of realizing them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention in conjunction with the accompanying drawings, in which:

[0008] Figure 1 is a logical block diagram depicting an exemplary sensing system for determining the state of a compression spring, where the compression spring shown is in a compressed state.

[0009] Figure 2 Shows the sensing system when the compression spring is in an extended state.

[0010] Figure 3A Shows another embodiment of a sensing system including a capacitive shield according to some embodiments.

[0011] Figure 3B Shows another embodiment of a sensing system according to some embodiments, which includes plates with interleaved sets of fingers to form interdigital capacitors.

[0012] Figure 4A is a circuit diagram of the circuit of the sensing system shown Figure 1 in FIG.

[0013] Figure 4B is a circuit diagram of the circuit of the sensing system shown Figure 2 in FIG.

[0014] Figure 5A is a circuit diagram of the circuit of the sensing system shown in FIG. 3 when the compression spring is in its compressed state.

[0015] Figure 5B is a circuit diagram of the circuit of the sensing system shown in FIG. 3 when the compression spring is in its extended state.

[0016] Figure 6 shows an exemplary method for determining the state of a compression spring according to some embodiments.

[0017] Figure 7 shows an exemplary drug delivery device in its initial pre-use configuration according to some embodiments.

[0018] Figure 8 shows the drug delivery device after its end cap has been removed but before the device has been activated to deliver the drug.

[0019] Figure 9 shows the drug delivery device after the device has been activated to deliver the drug.

[0020] Figure 10 shows an exemplary label wrapped around the outer surface of the drug delivery device according to some embodiments.

[0021] Figure 11 shows the label after being unfolded and laid flat.

[0022] Figure 12 shows a view of the back side of the label.

[0023] Figure 13 shows a second exemplary label wrapped around the outer surface of the drug delivery device according to some embodiments.

[0024] Figure 14 shows a view of the back side of the second label.

[0025] Figure 15 shows a view of the back side of a third exemplary label using a plate including multiple sets of interleaved fingers according to some embodiments.

[0026] In all of the several views, corresponding reference numerals indicate corresponding parts. The examples set forth herein illustrate exemplary embodiments of the invention and such examples should not be construed as limiting the scope of the invention in any way. Detailed Description

[0027] Figure 1 is a logical block diagram depicting an exemplary sensing system 102 for determining the state of a compression spring 104 according to some embodiments. The compression spring 104 can be any suitable spring made at least in part of a conductive material (e.g., metal). The components of the system 102 can receive power from a power source 114, which can be a battery, a supercapacitor, a utility grid, or a harvesting power source that inductively and wirelessly receives power from an external source (e.g., from an external device 150 as described below). The system 102 includes a first capacitor plate 108a configured to be located on a first side of the spring 104 and a second capacitor plate 108b configured to be located on a second side that is circumferentially spaced from the first side of the spring 104 such that the spring 104 is located between the first plate 108a and the second plate 108b (the plates 108a and 108b are collectively referred to as the plates 108). The plates 108 can take the form of any substantially planar or curved sheet formed at least in part of a conductive metal (or another conductive material). The system 102 also includes a temperature sensor 112 configured to sense temperature. According to different embodiments, the sensed temperature can be the temperature of the spring 104, the temperature of one or both of the plates 108, the temperature of any other component of the system 102 described herein, the temperature of the device or system in which the system 102 is installed or integrated, and / or the ambient temperature. The temperature sensor 112 can take the form of any suitable sensor for sensing temperature, such as but not limited to a thermistor (e.g., a negative temperature coefficient (NTC) thermistor or a resistance temperature detector (RTD)), a thermocouple, or a semiconductor-based temperature sensor.

[0028] The board 108 and the temperature sensor 112 are coupled to the processing circuit 106. The processing circuit 106 may take the form of a processor (e.g., a microprocessor or a microcontroller, a field programmable gate array (FPGA), and / or a digital signal processor (DSP), or any combination of the foregoing), which is configured to execute logic stored in a memory (not shown) to perform the operations described herein. The terms “logic,” “control logic,” “instructions,” or “application” used herein may include software and / or firmware executed on any of the foregoing processing circuits. The memory may be any suitable computer-readable medium accessible by the processing circuit 106 and includes volatile and non-volatile memories. Exemplary memories include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic storage devices, optical disc memories, or any other suitable medium configured to store data and accessible by the processor circuit 106 either directly or indirectly via one or more intermediate devices or a wired or wireless communication link. Although the foregoing description assumes that the memory is separate from and communicatively coupled / coupled to the processing circuit 106, in some embodiments, the memory may also be integrated with the processing circuit 106. In some embodiments, instead of a processor that executes logic stored in the memory, the processing circuit 106 may take the form of hardwired logic, such as a state machine and / or an application specific integrated circuit (ASIC) that performs the functions described herein. In the sensing system 102, the processing circuit 106 is electrically connected to the board 108 to measure the capacitance between the boards 108a and 108b. Similarly, the processing circuit 106 is also communicatively coupled to the temperature sensor 112 to determine the temperature sensed by the sensor 112 based on the signal output by the sensor 112. Although in Figure 1-2 FIG. the processing circuit 106 and the temperature sensor 112 are shown as separate elements, in some embodiments, the temperature sensor 112 and the processing circuit 106 may be integrated into a single integrated circuit.

[0029] The processing circuit 106 may also be communicatively coupled to the communication circuit 110. The communication circuit 110 may take the form of a circuit configured to transmit data to and / or from an external device 150 using any suitable wireless transmission protocol (e.g., but not limited to, cellular transmission protocols, Bluetooth Low Energy (BLE), Near Field Communication (NFC), and / or Radio Frequency Identification (RFID)). The processing circuit 106 may use the communication circuit 110 to transmit at least one of the measured capacitance, the measured temperature, and data indicating whether the compression spring is in a compressed state or an extended state to the external device 150. Although in Figure 1-2Processing circuitry 106 and communication circuitry 110 are shown as separate elements in FIG. 1 , but in some embodiments, communication circuitry 110 and processing circuitry 106 may be integrated into a single integrated circuit (possibly along with temperature sensor 112 ).

[0030] The external device 150 may include any device that receives, stores and / or processes data from the communication circuit 110 via the wireless signal 130 received by the communication circuit 156. Exemplary external devices include smart phones, smart watches, tablet computers, laptops, desktop computers, wireless hubs and / or WiFi access points. The wireless signal 130 may be an active signal, in which the external device 150 receives a signal sent by the communication circuit 110, or it may be a passive signal, in which the external device 150 senses the modulation of the signal sent by the communication circuit 156 caused by the communication circuit 110 (e.g., a passive NFC signal). Similar to the communication circuit 110, the communication circuit 156 may include any circuit configured to receive data from the processing circuit 106 and / or send data to it using any of the aforementioned wireless transmission protocols. The external device 150 may also include a processing circuit 152 and a memory 154, the processing circuit may take the form of any of the aforementioned types of processing circuits, and the memory may also take the form of any of the aforementioned types of memories. In some embodiments, the external device may also include a user interface for displaying data and / or receiving user input. For example, the user interface may include a graphical user interface (GUI) including a touch screen display. The touch screen display allows the user to interact with the information, menus, buttons and other data presented to provide information to the user or receive user input from the user. Alternatively, or in addition, a keyboard, keypad, microphone, mouse pointer or other suitable user input devices may be provided. External device 150 may also include a separate communication circuit configured to communicate with other devices (e.g., using a remote or cellular wireless transmission protocol).

[0031] Figure 1 1 shows the sensing system 102 when the compression spring 104 is in a compressed state. When in this compressed state, the coils of the spring 104 are closely spaced so that the sides of the spring act as capacitor plates positioned between the plates 108a and 108b. Thus, when the spring 104 is in its compressed state, the spring 104 and the plates 108 can be used to Figure 4A In the circuit diagram 402, the terminal 404 is considered to be connected to the processing circuit 106. PS represents the capacitance formed by one of the plates 108 and the side of the compression spring 104. C PS It can be calculated according to the following formula 1:

[0032] Formula 1:

[0033] where ε is the dielectric constant of the material (here mainly air, but may also include an intermediate layer of plastic or other material) between one of the plates 108 and the side surface of the spring 104, A is the surface area of the plate 108 (e.g., the product of length and width), and d ps is the distance between one of the plates 108 and the side surface of the spring 104 (see Figure 1 ).

[0034] Since there are two plates 108, when the spring 104 is in the compressed state, the total capacitance (C total，Comp ) measured by the processing circuit 106 between the two terminals 404 is given by Equation 2 below:

[0035] Equation 2:

[0036] This is because the relationship between the total capacitance (C cotal ) of two capacitors (C1 and C2) in series is given by Equation 3 below:

[0037] Equation 3:

[0038] If C1 = C2, as is the case here, then it can be deduced that

[0039] Figure 2 FIG. 31 shows the sensing system 102 when the compression spring 104 is in the extended state. When in this extended state, the coils of the spring 104 are more widely spaced, or at least farther apart than when the spring 104 is in its compressed state. When in this configuration, the side surfaces of the spring no longer function as (or function less effectively as) capacitor plates located between the plates 108a and 108b. As such, when the spring 104 is in its extended state, the spring 104 and the plates 108 can be simulated using the circuit diagram 403 in Figure 4B . Similar to the circuit diagram 402, the terminals 404 in the circuit diagram 403 are considered to be connected to the processing circuit 106. C PP represents the capacitance formed by the two plates 108 with no intermediate capacitor plates therebetween. C PP can be calculated according to Equation 4 below:

[0040] Equation 4:

[0041] where ε is the dielectric constant of the material (again, mainly air) between the plates 108, A is the surface area of the plates 108, and d pp is the distance between the plates 108 (see Figure 1 ).

[0042] D Pand D PP are configurable parameters depending on different embodiments. However, for illustrative purposes, assume d pp = x·d ps (where x is a configurable parameter), then the relationship between C PP and C PS is expressed by the following Formula 5:

[0043] Formula 5:

[0044] Furthermore, since C pp is the only capacitor in the circuit diagram 403, the total capacitance (C total，exp ) measured by the processing circuit 106 between the terminals 404 when the spring 104 is in the extended state is equal to C pp . Therefore, the relationship between C total，exp and C total，comp is given by the following Formula 6:

[0045] Formula 6:

[0046] Therefore, when the spring 104 transitions between the compressed state and the extended state (assuming x is not equal to 2), it can be expected that the capacitance measured by the processing circuit 106 will change. For example, if x equals 3, the capacitance measured by the processing circuit 106 when the spring 104 is in its extended state will be expected to be approximately 2 / 3 of the capacitance measured by the processing circuit 106 when the spring 104 is in its compressed state. Therefore, by measuring the capacitance of the system formed by the spring 108 and the spring 104, the processing circuit 108 can determine whether the spring is in its extended state or compressed state.

[0047] The inventors also recognize that the capacitance measured by the processing circuit 106 can vary with changes in the temperature of the components of the system 102, such as the spring 104, and the plate 108. This may be because as the temperature increases, the gaps between the links in the spring 104 may increase or decrease due to thermal expansion. Additionally, as the temperature increases, the capacitor plates 108 can expand, thereby increasing their surface area and thus increasing the measured capacitance. Also, as the temperature increases, the distance between the capacitor plates 108 and the spring 104 can change. Further, as the temperature increases, the thermal noise and / or other temperature dependencies that affect the measurements obtained by the capacitance sensors on the processing circuit 106 may increase, thus increasing the measured capacitance. In some cases, the inventors have observed that the capacitance measured by the processing circuit 106 can vary significantly between a first (lower) temperature and a second (higher) temperature, such that it may become difficult to determine whether the spring 104 is in its compressed or extended state based solely on the measured capacitance. In other words, in some use cases, the capacitance measured when the spring is in its compressed state at a first temperature may be too close to the capacitance measured when the spring is in its extended state at a second temperature. This makes it difficult to determine whether the spring 104 is in its compressed or extended state based solely on the measured capacitance without considering the temperature of the system 102.

[0048] This is especially true when the system 102 is used to detect the state of the spring within a drug delivery device that needs to be refrigerated for storage. Many types of injectable drugs need to be stored at a lower temperature (e.g., 36 - 46 degrees Fahrenheit, or 2 - 8 degrees Celsius) to prevent degradation, but need to be heated to a higher temperature (e.g., heated to room temperature, or 65 - 75 degrees Fahrenheit) before being injected into a patient. A drug delivery device for storing and delivering such drugs can come with instructions for use that direct the patient to store such devices in their refrigerator, but to remove the device and heat it to room temperature before administering the drug. In some embodiments, the capacitance measured when the spring is in its compressed state at a lower temperature (e.g., in the refrigerator) may be too close to the capacitance measured when the spring is in its extended state at a higher temperature (e.g., room temperature), resulting in the sensing system 102 mounted on such a drug delivery device being unable to reliably determine which state the spring is in without considering the temperature.

[0049] Accordingly, the system 102 can include a temperature sensor 112 communicatively coupled to the processing circuit 106. The sensor 112 allows the processing circuit 106 to measure the ambient temperature, or the temperature of one or more components of the system 102 (e.g., the spring 104 and / or the plate 108). By considering the temperature measured by the sensor 112, the processing circuit 106 can more accurately determine whether the spring 102 is in its compressed or extended state.

[0050] For example, when the measured capacitance of the plate 108 is greater than the capacitance threshold, the processing circuit 106 can determine that the spring 102 is in its compressed state. Conversely, when the measured capacitance is less than the capacitance threshold, the processing circuit 106 can determine that the spring 102 is in its extended state. The processing circuit 106 can be further configured to adjust the capacitance threshold based on the temperature measured by the sensor 112. For example, the processing circuit 106 can increase the capacitance threshold as the temperature increases and decrease the capacitance threshold as the temperature decreases. The processing circuit 106 can achieve this in any of a variety of ways, including: (i) defining two or more temperature ranges (e.g., high / low, high / mid / low, or any other number of temperature ranges), where each temperature range is distinguished from the other temperature ranges by a temperature threshold, and implementing logic to set the capacitance threshold according to the temperature range in which the current temperature lies, and / or (ii) deriving the capacitance threshold to be applied by multiplying the current temperature by a pre-programmed conversion constant. Any known mathematical or logical method for changing the capacitance threshold based on the temperature measured by the sensor 112 can be used. In this way, the processing circuit 106 can better determine whether the spring 102 is in its compressed state or its extended state based on the measured capacitance of the plate 108 and the temperature measured by the sensor 112.

[0051] In some embodiments, the processing circuit 106 can be configured to measure the capacitance between the plates 108 and the temperature measured by the sensor 112 and transmit the measurement data to the processing circuit 152 in the external device 150. The processing circuit 152 then determines whether the spring 104 is in a compressed state or an extended state based on the measured and received capacitance and temperature data. In other embodiments, the processing circuit 106 and the processing circuit 152 can work together to determine whether the spring is in a compressed state or an extended state.

[0052] Figure 3A An embodiment of the system 102 including a capacitance shield 114 is shown. For simplicity, in Figure 3AThe temperature sensor 112 is not shown in the figure, but it should be understood that such a temperature sensor can be connected to the processing circuit 106 and / or integrated with the processing circuit. In this embodiment, the plates 108a and 108b are configured as curved plates that conform to the curvature of the spring 104. Additionally, the capacitive shield 114 can be configured as a layer of metal or conductive material shaped like an entire cylinder or a partial cylinder, and it surrounds all or part of the plates 108 and the spring 104. Similar to the plate 108, the shield 114 can also be electrically connected to the processing circuit 106. The shield 114 can reduce the effect of any conductive object (e.g., the user's hand) that contacts or is positioned close to the plate 108 on the capacitance measured by the processing circuit 106. By reducing the magnitude of any such interference on the measured capacitance, the shield 114 reduces the likelihood of such interference that causes the processing circuit 106 to erroneously determine that the spring is in its compressed state when the spring 104 is actually in its extended state (or vice versa). In some embodiments, a polyester film (or a layer of some other dielectric material) (not shown) can be inserted between the plate 108 and the shield 114 to space these components apart from each other.

[0053] Figure 3B Another embodiment of the system 102 is shown, which instead of using two solid curved plates 108a and 108B, uses two "plates" 109a, 109B (collectively referred to as the plate 109), where each plate includes a set of spaced-apart parallel fingers that are at least partially formed of metal or conductive material, and the fingers cover at least a portion of the surface of the spring 104. The first "plate" including the fingers 109a is electrically connected to the first conductive strip 111a, while the second "plate" including the fingers 109b is electrically connected to the second conductive strip 111b. As Figure 3B shown, the two plates are arranged such that the fingers of each plate are interleaved with each other in an alternating manner, thus forming an interdigital capacitor. The conductive strips 111A and 111B are then communicatively coupled to the processing circuit 106. Although not shown in Figure 3B , it should be understood that a capacitive shield 114 can also be provided that surrounds all or part of the plates 109a, 109B and the conductive strips 111a, 111B.

[0054] When the spring 104 is in its compressed state, the spring 104, the plate 108 (or 109), and the shield 114 can be simulated using the circuit diagram 502 shown in Figure 5A . In the circuit diagram 502, the terminal 504 is considered to be connected to the processing circuit 106. As previously mentioned, C ps represents the capacitance formed by one of the plates 108 (or 109) and the side of the compressed spring 104. C p,shield represents the capacitance formed by one of the plates 108 or 109 and the shield 114. C psIt can be calculated according to Formula 1. C p,shield It can be calculated using the following Formula 7:

[0055] Formula 7:

[0056] where ε PET is the dielectric constant of the dielectric material layer inserted between the plates 108 / 109 and the shield 114 (if the dielectric material is polyester, ε PET can be expected to be about 2.8 times the air dielectric constant), A is the surface area of the plates 108 / 109, and d PET is the thickness of the dielectric material layer. For example, in some embodiments, d PET can be about 40 μm.

[0057] Since the capacitance of two series capacitors is given by Formula 3, when two capacitors with capacitance C p,shield are in series, the capacitance (C offset ) is given by the following Formula 8:

[0058] Formula 8:

[0059] In addition, since the capacitance of two parallel capacitors is equal to the sum of the capacitances of these two capacitors, when the spring 104 is in its compressed state and there is a shield 114, the capacitance (C total,comp,shielded ) measured by the processing circuit 106 is given by the following Formula 9:

[0060] Formula 9: C total，comp，shielded = C total，comp + C offset

[0061] When the compression spring 104 is in its extended state, the spacing between the coils of the spring 104 is larger. As described above, when in this configuration, the sides of the spring no longer function as (or function less effectively as) capacitor plates located between the plates 108a and 108b (or 109a and 109b). Therefore, when the spring 104 is in its extended state, the circuit diagram 503 in Figure 5B can be used to simulate the spring 104, the plates 108 or 109, and the shield 114. Similar to the circuit diagram 502, the terminal 504 is considered to be connected to the processing circuit 106. It can be seen that the circuit diagram 503 is the same as the circuit diagram 403, except that two capacitors with capacitance C p,shield are connected in parallel with C pp . Therefore, when the spring 104 is in its extended state and there is a shield 114, the capacitance (C total、exp、shielded ) measured by the processing circuit 106 is given by the following Formula 10:

[0062] Formula 10: Ctotal，exp，shielded = C total，exp + C offset

[0063] Thus, adding the shield 114 is expected to give a total capacitance C when the spring 104 is in the compressed state total,comp and a total capacitance C when the spring 104 is in the extended state total,exp an increased capacitance C offset . By considering C offset , the capacitance measured by the processing circuit 106 can still be used as an indicator for determining whether the spring 104 is in the compressed state or the extended state.

[0064] Figure 6 FIG. 600 shows an exemplary method 600 for determining the state of a compression spring according to some embodiments. The method 600 can be implemented using the sensing system 102. The method 600 starts at step 602, where a first capacitor plate (e.g., plate 108a or 109a) is located on a first side of a compression spring (e.g., spring 104). In step 602, a second capacitor plate (e.g., plate 108b or 109b) is arranged on a second side opposite the first side of the compression spring. In some embodiments, the second capacitor plate is arranged such that the compression spring is located between the first capacitor plate and the second capacitor plate. In step 606, the temperature is measured using a temperature sensor (e.g., temperature sensor 112). In step 608, the capacitance between the first capacitor plate and the second capacitor plate is measured. This measurement can be performed using a processing circuit such as the processing circuit 106. In step 610, the processing circuit determines whether the compression spring is in the compressed state or the extended state based on the measured capacitance and the measured temperature. This determination can be made using any method described herein. The processing circuit making this determination can be, for example, the processing circuit 106. Alternatively, based on the measured capacitance and temperature data, the processing circuit making this determination can be the processing circuit 152 at the external device 150, and the measured capacitance and temperature data are measured and wirelessly transmitted from the processing circuit 106 via the communication circuits 110 and 156. In some embodiments, this determination can be made by two or more processing circuits, such as the processing circuit 106 and the processing circuit 152, which are communicatively coupled to each other (e.g., via a wired or wireless data link) and configured to cooperatively process the measured capacitance and / or temperature data to determine the state of the spring 104.

[0065] In some embodiments, the compression spring can be part of a drug delivery device, as described in further detail herein. The drug delivery device can be configured to be activated to dispense a drug, and when activated, to transition the compression spring from the compressed state to the extended state, or from the extended state to the compressed state. The transition of the spring between these states can be used to move the syringe assembly between a retracted position and an injection position, or vice versa.

[0066] In some embodiments, the method may further include reporting at least one of the measured capacitance, the measured temperature, and / or data indicating whether the compression spring is in a compressed state or an extended state to an external device via wireless communication. The wireless communication may be accomplished using the communication circuit 110 and any wireless communication protocol associated therewith.

[0067] In Figures 7-9 it, a drug delivery device 20 that can be used in conjunction with the sensing system 102 in a variety of different operating states is described. An example of such a device and its operation is described in U.S. Patent No. US8,734,394B2, issued to Adams et al. on May 27, 2014, and U.S. Patent Application Publication No. US2021 / 0093784A1, issued to Adams et al. on April 1, 2021, the entire disclosure of each patent document being incorporated herein by reference. The device 20 includes a syringe assembly 22, a drive mechanism 24, and a retraction mechanism 26. The syringe assembly 22 includes a cartridge 30 that forms a container body for containing a drug, and a piston 32 disposed within the cartridge 30 for driving the drug out of the cartridge. The syringe assembly 22 further includes a needle assembly 33 having a hollow injection needle 34 and a needle hub 35 that mounts the needle 34 to the syringe barrel 30. A lower support member 29 connected to the device housing 38 surrounds the needle 34 and pushes the piston 32 toward the needle 34 within the cartridge 30 to dispense the drug through the needle 34.

[0068] The devices described herein, such as device 20, may also include a drug, such as within syringe cartridge 30. In another embodiment, the system may include one or more devices, including device 20 and the drug. The drug includes one or more therapeutic agents, including but not limited to insulin, insulin analogs (such as lispro insulin or insulin glargine), insulin derivatives, GLP-1 receptor agonists (such as dulaglutide or liraglutide), glucagon, glucagon analogs, glucagon derivatives, gastric inhibitory polypeptide (GIP), GIP analogs, GIP derivatives, combination GIP / GLP-1 agonists (such as tirzepatide), oxyntomodulin analogs, oxyntomodulin derivatives, therapeutic antibodies (including but not limited to IL-23 antibody analogs or derivatives, such as mirikizumab), IL-17 antibody analogs or derivatives (such as ixekizumab), therapeutic agents for pain-related treatments (such as galcanezumab or ramelteon), and any therapeutic agent capable of being delivered by the devices described herein. The drug used in the device may be formulated with one or more excipients. The device is operated by a user, caregiver, or healthcare professional in substantially the manner described above to deliver the drug to a patient. As used herein, the term "user" may refer to the operator of the device described herein, and the term "patient" may refer to the person receiving the drug. In some cases, the user and the patient may be the same person (e.g., the patient is operating the device described herein to give himself / herself an injection). In other cases, the user and the patient may be different people (e.g., the user may be a person providing care to the patient).

[0069] Figure 7 Device 20 is shown in its pre-initial-use configuration. Here, end cap 36 is secured to lower support member 29 (which is in turn coupled to device housing 38). End cap 36 covers proximal opening 40 in housing 38. As used herein, distal and proximal refer to the axial position relative to a site when the device is oriented for use at an injection site, whereby, for example, the proximal end of the housing refers to the housing end closest to the injection site, and the distal end of the housing refers to the housing end furthest from the injection site. Also as used herein, an "injection site" may refer to the precise point on a patient's body where a needle is injected, as well as the body tissue surrounding the point where the needle is injected (e.g., within 1-5 cm or 1-10 cm of the point where the needle pierces the patient's skin). Housing 38 may be formed of a plastic material and is shown extending generally longitudinally along longitudinal axis 48 between a distal end adjacent operation button 52 and a proximal end adjacent proximal opening 40. As Figure 8As shown, the housing 38 may include a user-grippable portion 37 configured to be gripped by a user's hand, and the user-grippable portion 37 extends radially outward from the longitudinal axis 48 by a radial distance 41. In some embodiments, the length of the radial distance 41 may be between 5 - 10 mm (e.g., in some embodiments, 5 - 8 mm may be a suitable length). Also as Figure 8 shown, the housing 38 may further include an outwardly expanded end 39 adjacent to the proximal opening 40 at the proximal end of the housing.

[0070] The needle sheath 42 is mounted on the syringe assembly 22, covering and surrounding the needle 34. The end cap 36 and the needle sheath 42 protect the user from accidental needle sticks and also protect the needle 34 from damage. When using the device 20 to dispense a drug, for example, when injecting the drug into a patient, the end cap 36 and the needle sheath 42 are first removed. Figure 8 The device 20 is shown after removing the end cap 36 and the needle sheath 42 from the syringe assembly 22, where the syringe assembly is in the storage position and the device 20 is ready for the dispensing event.

[0071] The syringe assembly 22 is movable relative to the drug delivery device 20 between a storage position and an injection position. Figure 9 The syringe assembly 22 is shown relative to the device 20 after moving from Figure 8 the storage position shown to the injection position ( Figure 7 and 8 ), and the needle 34 is retracted to a position where the needle 34 is disposed within the housing 38 of the device 20. At the injection position ( Figure 9 ), the needle 34 projects outwardly from the housing 38 in a proximal direction parallel to the longitudinal axis 48 beyond the proximal opening 40, whereby the needle 34 can be inserted into the patient.

[0072] The drive mechanism 24 includes a plunger 44 that engages the piston 32, and the drive mechanism 24 includes a spring 46 that drives the plunger 44 to move linearly. In the illustrated embodiment, the spring 46 advances the plunger 44 along a linear path defined by the longitudinal axis 48 of the device 20. When the plunger 44 advances, the bottom 50 of the plunger 44 contacts the piston 32. When the plunger 44 further advances, the syringe assembly 22 advances from its storage position to its injection position along the longitudinal axis 48. After the syringe assembly 22 advances to its injection position, the continued proximal advancement of the plunger 44 causes the piston 32 to advance proximally within the cartridge 30 from its initial piston position ( Figure 7 and 8 as shown therein) to its final piston position ( Figure 9As shown in [Figure number not provided], to dispense the drug from the dispensing needle 34 during a dispensing event. Before any drug is dispensed, and when the syringe cartridge 30 holds the full initial volume of the drug, the piston 32 will be in its initial piston position. After the piston 32 has advanced its entire stroke length towards the needle assembly 33, the piston 32 will be in its final piston position near the needle assembly 33, and the drug within the cartridge 30 will be expelled. In some embodiments, the syringe assembly 22 will hold a single dose of the drug, which will be delivered during a single injection event, and the piston 32 will advance from its initial piston position to its final piston position during that single injection event, thereby delivering the entire single dose content of the syringe assembly 22. Although the device is shown as a single-use device, the device 20 can also be configured as a multi-use device with appropriate modifications.

[0073] Before the syringe assembly 22 is advanced to the injection position, the advancement of the plunger 44 generally does not result in the dispensing of the drug from the syringe assembly 22. Before the syringe is advanced to the injection position, there are some factors that may prevent drug dispensing. One factor is the friction between the piston 32 and the cartridge 30. Generally, the piston 32 can be made of a rubber material and the cartridge 30 is made of glass. The frictional resistance between these two components is sufficient to prevent the piston 32 from advancing within the cartridge 30 until the syringe assembly 22 is advanced to its injection position and engages with a suitable stop member to prevent further advancement of the syringe assembly 22. Additionally, the drug within the syringe may have a certain viscosity, which creates a certain resistance to the expulsion of the drug through the needle 34. If desired, by changing the piston 32 and the syringe cartridge 30, the frictional resistance of the dispensing movement of the engagement member 32 relative to the syringe cartridge 30 can be changed, which can limit or prevent premature dispensing of the drug before the syringe assembly 22 reaches the injection position.

[0074] To activate the drive mechanism 24, the user presses the operation button 52 located at the distal end of the device 20. Pressing the operation button 52 disengages one or two elongate claws 54 on the plunger 44 from the slider assembly 60, thereby allowing the spring 46 to expand to axially advance the plunger 44. The spring 46 has a helical shape and surrounds the claws 54, and the proximal end of the spring 46 is biased to engage a flange on the plunger 44.

[0075] The slider assembly 60 can include an upper slider member 62 and a lower slider member 64, and the slider members 62, 64 are fixed together in the final assembly. In the final assembly, the upper slider member 62 houses the button 52 and the spring 46, thereby restricting the axial movement of these components in the distal direction. When the device is in Figure 7 and 8In the state shown, the pointed claw 54 engages the upper surface of the upper slider member 62. Pressing the button 52 causes the tab on the button 52 to engage the inclined surface (not shown) on the pointed claw 54 to bias the pointed claw 54 inwardly, thereby disengaging the pointed claw 54 from the upper slider member 62. After the pointed claw 54 has been disengaged, the spring 46 applies a biasing force on the flange of the plunger 44 so that the plunger 44 advances from the Figure 8 position shown to the Figure 9 position shown. When the plunger 44 advances, it moves the syringe assembly 22 to the injection position and then pushes the piston 32 to dispense the drug, as described above.

[0076] After the dispensing event is completed, the retraction mechanism 26 optionally moves the syringe assembly 22 from the Figure 9 injection position shown back to the retracted position. More specifically, the retraction mechanism is adapted to move the drug container from the injection position to the retracted position during the retraction movement. The retracted position may be similar to the storage position, where the syringe assembly is pulled back into the housing 38 such that the needle 34 no longer projects proximally from the proximal opening 40 and is fully within the housing 38. In some embodiments, the retracted position may be the same as the storage position. However, in other embodiments, the syringe assembly 22 in the retracted position may be positioned slightly closer to or farther from the syringe assembly in the storage position. In the illustrated embodiment, the retraction mechanism includes a spring 66, a syringe carrier, and a rotating member 70 acting as a follower. In still other embodiments, the device 20 may not include the retraction mechanism 26 such that the syringe assembly remains in its injection position indefinitely after drug dispensing until the user manually removes or repositions the syringe assembly.

[0077] The plunger 44 may include an extended bracket (not shown) that unlocks the rotating member 70 when the plunger 44 approaches the end of its stroke in the proximal direction. The rotating member 70 is rotatably fixed to the lower slider member 64 by the engagement between a latch and a latch groove in the lower slider member 64, and the extended bracket unlocks the rotating member 70 by depressing the latch. The spring 66 is torsionally preloaded and has one end engaging the rotating member 70 and an opposite end engaging the slider assembly 60. When the latch is depressed, the spring 66 rotates the rotating member 70.

[0078] The rotating member 70 is rotatable within the housing 38 but not axially movable relative to the housing 38. Other embodiments may include a member 70 that is also axially movable. Rotation of the member 70 functions as a delay mechanism to prevent the retraction mechanism 26 from retracting the syringe assembly 22 before the syringe assembly 22 has completed drug delivery. The rotational speed of the member 70 can be adjusted by adjusting the viscosity of the grease disposed on or around the surface of the member 70 that contacts the housing 38. The higher the viscosity of the grease, the slower the rotational speed, and the lower the viscosity of the grease, the faster the rotational speed. Radial flanges on the rotating member 70 can engage protrusions within the housing member 38 to limit proximal movement of the member 70, and the spring 66 can also be preloaded in a compressed state such that it is initially in a compressed state. In the compressed state, the spring 66 can apply an axial force, a torsional force, or both forces on the member 70 to bias the member 70 proximally, thereby holding the member 70 in an axial position where the radial flanges of the member 70 engage the internal protrusions of the housing member 38.

[0079] The slider assembly 60 may include axially extending channels or ribs that engage corresponding structural features on the housing 38, which allow the slider assembly 60 to move axially within the housing 38 but prevent relative rotation of the slider assembly 60 relative to the housing 38. Before the drive mechanism 24 is activated, the slider assembly 60 is biased in the distal direction by the spring 66 but is prevented from moving distally by the engagement of a latch (not shown). When the rotating member 70 has completed its rotation, the rotating member disengages from the aforementioned latch, thereby allowing the slider assembly 60 to move distally under the biasing force of the spring 66.

[0080] When the slider assembly 60 moves distally, it carries the syringe assembly 22 distally and moves it back to the retracted position. Similarly, when the slider assembly 60 moves, the spring 66 transitions from its compressed state to its extended state. The spring 66 biases the retraction mechanism 26 distally, thereby holding the syringe assembly 22 in its retracted position after the injection event. In some embodiments, when the slider assembly 60 moves distally, the spring 46 of the drive mechanism 24 may also transition from its extended state to its compressed state. A locking mechanism such as a pawl on the slider assembly 60 and a recess on the housing 38 member can additionally provide a locking engagement to fix the syringe assembly 22 in the retracted position after the injection event, where the needle 34 is located within the housing 38, whereby the user can subsequently place or otherwise operate the device 20 in a safe manner.

[0081] Figure 10 A label 1000 is shown wrapped around the outer surface of the user-grippable portion 37 of the drug delivery device 20, while Figure 11Shows the deployed and flat label 1000 according to some embodiments. The label 1000 may include a flexible paper and / or plastic material that can be attached to the outer surface of the device 20. The label 1000 can be attached using any of a variety of methods, including (but not limited to) using adhesives, adhesive films (e.g., polyurethane films), magnetic attachments, clip attachments, ultrasonic bonding / welding, injection molding / in-mold labeling, laser bonding / welding, etc. The label 20 can be printed with information about the device 20 and / or about the drug stored in the device 20, such as the drug name, manufacturer name, manufacturing batch / lot number, expiration date, instructions for use and / or storage, the amount of drug stored therein, etc.

[0082] The sensing system 102 can be mounted on and / or integrated with the label 1000 to provide the label 1000 with the ability to sense whether the compression springs (e.g., spring 46 of the drive mechanism 24 and / or spring 66 of the retraction mechanism 26) within the drug delivery device 20 are in a compressed state or an extended state. This determination of the state of the compression springs within the device 20 can indicate whether the device 20 has been activated to deliver the drug, and / or whether the device 20 has completed the delivery of the drug. For example, since spring 46 transitions from a compressed state to an extended state when the drug delivery device 20 is activated to dispense the drug, the sensing system 102 mounted on and / or integrated with the label 1000 can be used to detect the state of spring 46 and thereby infer whether the drug delivery device 20 has been activated. As another example, since spring 66 transitions from a compressed state to an extended state when the drug delivery device 20 retracts the syringe assembly 22 at the end of the injection, the sensing system 102 mounted on and / or integrated with the label 1000 can be used to detect the state of spring 66 and thereby infer whether the drug delivery device 20 has completed the retraction of its syringe assembly 22, and / or whether it has completed its injection. As yet another example, since in some embodiments spring 46 can transition from an extended state to a compressed state when the drug delivery device 20 retracts the syringe assembly 22 at the end of the injection, the sensing system 102 mounted on and / or integrated with the label 1000 can be used to detect the state of spring 46 and thereby infer whether the drug delivery device 20 has completed the retraction of its syringe assembly 22, and / or whether it has completed its injection. The sensing system 102 mounted on and / or integrated with the label 1000 can also use the communication circuit 110 to transmit its determination / judgment result regarding the sensed state of the compression spring to an external device, such as the external device 150. The external device can infer from this information whether the user has taken and / or completed the injection, record such information and / or inference, and / or transmit such information and / or inference to other devices for storage, analysis, and / or further action.

[0083] Figure 12Shows a view of the back side of an exemplary tag 1000 according to a first embodiment (e.g., the surface configured to surround and / or adhere to the outer surface of the drug delivery device 20), which is attached to and / or integrated with the sensing system 102. The tag 1000 includes a processing circuit 1206, which is configured similarly to the processing circuit 106 and performs the same functions. Although not shown separately, the processing circuit 1206 may also include a temperature sensor similar to the sensor 112, as described above. The processing circuit 1206 may be an unpackaged "chip-on-bump" integrated circuit, equipped with an on-board temperature sensor and a capacitive sensing interface. Such a circuit may have an exemplary thickness of 0.15 mm or less and is mounted on a flexible substrate, allowing the circuit to be easily adhered to the cylindrical user-grippable portion 37 of the drug delivery device 20.

[0084] The tag 1000 also includes capacitor plates 1208a and 1208b (collectively referred to herein as plates 1208), which are configured similarly to the plates 108a and 108b and perform the same functions. The tag 1000 also includes a conductive shield 1214, and when the tag 1000 is wrapped around the outer surface of the user-grippable portion 37 of the drug delivery device 20, the conductive shield covers the capacitor plates 1208 and protects the capacitor plates 1208 from contact with the user's hand (or from capacitive interference from the user's hand). The shield 1214 is separated from the capacitor plates by a thin layer of dielectric material (e.g., Mylar film), as described above. The shield 1214 may also be electrically connected to the processing circuit 1206 via a wire or conductive trace passing through the thin layer of dielectric material through a via 1216. The tag 1000 also includes a near-field communication (NFC) loop antenna 1210 that is communicatively coupled to the processing circuit 1206. These NFC antennas correspond to the communication circuit 110 as described above. In addition to transmitting data to an external device, the NFC antenna 1210 can also be used to inductively and wirelessly collect power from the external device.

[0085] The back side of the tag 1000 can be mounted on and / or attached to the outer surface of the drug delivery device 20 (or some other surface of the device 20). For example, the tag 1000 can wrap around and adhere to the outer surface of the user-grippable portion 37 of the drug delivery device 20. When the tag 1000 is attached in this manner, the plate 1208 can be located on opposite sides of the spring 46, the spring 66, or some other spring within the drug delivery device 20, and any of the techniques described herein can be used to detect whether the sensed spring is in a compressed state or an extended state. As previously mentioned, the processing circuit 1206 can use data related to the state of the sensed spring to determine whether the device 20 has been activated to dispense a drug and / or has completed drug dispensing. Alternatively or additionally, the tag 1000 can be configured to wirelessly transmit data related to the capacitance between the plates 1208 measured by the processing circuit 1206 and / or the temperature sensed by its on-board temperature sensor to a processing circuit on an external device (e.g., the processing circuit 152 in the external device 150), thereby allowing the external device to determine whether the sensed spring is in a compressed state or an extended state.

[0086] In some embodiments, the tag 1200 can be modified to remove the shield 1214. As previously mentioned, the shield 1214 can be used to reduce capacitive interference from the user's hand when the user grips the user-grippable portion 37 of the drug delivery device 20. However, in some embodiments, the shield 1214 can be intentionally removed so that the capacitive plates 1208 can be used to sense whether the user is gripping the drug delivery device 20. When the shield 1214 is not installed, the capacitance of the plates 1208 measured by the processing circuit 1206 can change depending on whether the user is gripping the user-grippable portion 37 of the drug delivery device 20. This change in capacitance can be used to allow the processing circuit 1206 to determine whether the user is gripping the device 20.

[0087] Figure 13 Another exemplary tag 1300 wrapped around the outer surface of the user-grippable portion 37 of the drug delivery device 20 is shown in accordance with some embodiments. Figure 14 A view of the back side of the tag 1300 is shown. The tag 1300 is configured similarly to the tag 1000, except that the tag 1300 includes an additional marker 1302 extending from one side of the rectangular tag 1300. When the tag 1300 is wrapped around the drug delivery device 20, the marker 1302 is configured to overlap a portion of the tag 1300, as Figure 13 shown.

[0088] Similar to tag 1000, tag 1300 also includes a processing circuit 1406, which is configured similarly to processing circuit 106 and performs the same functions. Different from processing circuit 1306, processing circuit 1406 does not need to be directly adhered to the surface of the drug delivery device 20, and thus does not need to be as thin and / or flexible as processing circuit 1306. For example, processing circuit 1406 can be formed by an encapsulated NFC chip having a thickness of about 1 mm or greater. The encapsulated NFC chip can be equipped with an on-board temperature sensor and a capacitive sensing interface, and does not need to be mounted on a flexible substrate that enables the chip to bend. Such an encapsulated chip can be easier to purchase and / or manufacture than the thinner and more flexible processing circuit 1306, thereby reducing the manufacturing cost.

[0089] In other respects, tag 1300 is substantially similar to tag 1000. Tag 1300 also includes capacitor plates 1408a and 1408b, which are configured similarly to capacitor plates 1208 and 108 and perform similar functions. Tag 1300 also includes a conductive shield 1414 separated from capacitor plate 1408 by a thin insulating film (e.g., a polyester film). Shield 1414 is configured similarly to shields 1214 and 114 and performs similar functions to them, and is electrically connected to processing circuit 1406 via a wire or conductive trace passing through via 1416 through the polyester film. Tag 1300 also includes an NFC loop antenna 1410 communicatively coupled to processing circuit 1306. These NFC antennas correspond to communication circuit 110 as described above. In addition to transmitting data to an external device, NFC antenna 1410 can also be used to inductively and wirelessly obtain power from the external device.

[0090] Figure 15 A view of the back of yet another exemplary tag 1500 is shown. Tag 1500 is configured similarly to tag 1300, except that instead of using capacitor plates 1408a and 1408b, tag 1500 uses a first plate 1509a including a first set of finger-like portions that interleave with a second set of finger-like portions from a second plate 1509b to form an interdigital capacitor. In other respects, tag 1500 is substantially similar to tag 1300. Tag 1500 also includes a processing circuit 1506 configured similarly to processing circuit 106, and an NFC loop antenna 1510 communicatively coupled to processing circuit 1506, and these NFC antennas correspond to communication circuit 110 as described above. Although not shown in Figure 15 it should be understood that tag 1500 can also be provided with a capacitive shield similar to shields 1414, 1214, and / or 114.

[0091] Although the foregoing embodiments have been described as systems for detecting whether a spring is in a compressed state or an extended state, in some embodiments, a processing circuit (e.g., processing circuits 106, 152, 1206, 1406, and / or 1506) may be configured to detect whether a body part of a user is positioned close to a capacitor plate. The processing circuit may perform this function in addition to, or as an alternative to, the foregoing methods for detecting the compressed / extended state of the spring.

[0092] For example, in an embodiment where system 102 is for a drug delivery device (e.g., device 20 described above in Figures 7-9 ), the processing circuit may use the measured capacitance of capacitor plates (e.g., plates 108, 1208, 1408, and / or 1508) to determine whether a user's hand is grasping the drug delivery device (e.g., grasping Figure 8 the user-graspable portion 37 shown in ). In such an embodiment, the capacitor shield (e.g., shields 114, 1214, 1414) may be omitted. When the user grasps the drug delivery device, the processing circuit may detect a measurable increase in the measured capacitance of the capacitor plate. Based on this detected capacitance increase, processing circuit 106 and / or processing circuit 152 may determine whether the drug delivery device is being grasped by the user's hand or not being grasped by the user's hand.

[0093] In some embodiments, a single set of capacitor plates 108 (e.g., capacitor plates 108a and 108b) may be used to detect whether a user is grasping the drug delivery device and whether the spring is in a compressed state or an extended state. For example, when the processing circuit measures a capacitance greater than a first maximum capacitance threshold, the processing circuit may determine that the spring is in a compressed state and the user's hand is grasping the drug delivery device. When the processing circuit measures a capacitance lower than a second minimum capacitance threshold, the processing circuit may determine that the spring is in an extended state and the user's hand is not grasping the drug delivery device. When the processing circuit measures a capacitance between the first maximum capacitance threshold and the second minimum capacitance threshold, the processing circuit may determine (1) that the spring is in an extended state and the user's hand is grasping the drug delivery device, or (2) that the spring is in a compressed state and the user's hand is not grasping the drug delivery device.

[0094] In some embodiments, a drug delivery device (or a label for a drug delivery device) may be provided with multiple sets of capacitor plates. The first set of plates may be positioned and configured to detect whether spring 104 is in a compressed state or an extended state. The first set of plates may be provided with a capacitor shield similar to the aforementioned shields 114, 1214, and 1414. A second set of capacitor plates (or additional individual capacitor plates) may be positioned and configured to determine whether a user's hand is grasping the drug delivery device. The second set of plates may not be shielded. In this way, the processing circuit 106 may determine (1) whether the spring is in an extended state or a compressed state based on the capacitance measured by the first set of plates, and (2) whether the user is grasping the drug delivery device based on the capacitance measured by the second set of plates.

[0095] In additional embodiments, a drug delivery device (or a label for a drug delivery device) may be provided with three sets of capacitor plates. The first set of capacitor plates may be positioned and configured to determine whether spring 46 is in a compressed state or an extended state. This determination may assist the processing circuit 106 in determining whether the drug delivery device has started an injection, since spring 46 extends at the start of an injection. The second set of capacitor plates may be positioned and configured to determine whether spring 66 is in a compressed state or an extended state. This determination may assist the processing circuit 106 in determining whether the drug delivery device has completed an injection, since spring 66 extends when the injection is completed and the syringe assembly retracts. A third set of plates (or additional individual plates) may be positioned along the user-grippable portion 37 of the drug delivery device 20 and configured to determine whether the user is grasping the drug delivery device. The first and second sets of capacitor plates may be provided with capacitor shields, while the third set of capacitor plates may be unshielded.

[0096] The capacitor plates and the processing circuit in the above embodiments may also be modified such that the processing circuit is able to determine whether the device is grasped by only one hand of the user or by both hands. For example, the aforementioned capacitor plates may be enlarged (or multiple sets of capacitor plates may be provided) to cover a relatively large area of the user-grippable portion 37 of the drug delivery device 20. If the device is grasped with both hands, the capacitance of the capacitor plates measured by the processing circuit may be higher than the case where the device is grasped by only one hand. In this way, the processing circuit may determine whether the device is grasped by one hand, grasped by both hands, or not grasped at all. If the aforementioned capacitor plates are also placed near the end of the drug delivery device that contacts the user's injection site during an injection, the aforementioned capacitor plates may also be used to detect whether the drug delivery device is in contact with the injection site on the user's body. This additional detection function for detecting contact with the injection site may be a function in addition to the above detection functions, or as an alternative to the above detection functions, i.e., detecting the compressed and / or extended state of the spring and detecting whether the drug delivery device is being grasped by one or more hands of the user.

[0097] The terms "first", "second", "third", etc., whether used in the specification or in the claims, are provided to distinguish similar elements and are not necessarily intended to describe an order or a temporal sequence. It should be understood that the terms so used are interchangeable under appropriate circumstances (unless clearly disclosed otherwise), and the embodiments of the invention described herein are capable of operating in sequences and / or arrangements different from those described or illustrated herein.

[0098] Although the present invention has been described with an exemplary design, the present invention may be further modified within the spirit and scope of the present invention. Accordingly, this application is intended to cover any variations, uses, or modifications of the present invention that use the general principles of the present invention. In addition, this application is intended to cover such departures from the present invention as come within known or customary practice in the art to which the present invention pertains and fall within the limits of the appended claims.

[0099] Multiple aspects are described in the present invention, including but not limited to the following aspects:

[0100] 1. A drug delivery device having a sensing system for determining the state of a compression spring of the drug delivery device, the sensing system comprising: a first capacitor plate and a second capacitor plate configured such that the compression spring is located between at least a portion of the first capacitor plate and at least a portion of the second capacitor plate; a temperature sensor; and at least one processing circuit connected to the first capacitor plate, the second capacitor plate, and the temperature sensor, the at least one processing circuit being configured to: measure the capacitance between the first capacitor plate and the second capacitor plate, measure the temperature based on a signal output by the temperature sensor, and determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

[0101] 2. The drug delivery device according to claim 1, wherein the at least one processing circuit comprises a first processing circuit and a second processing circuit, and wherein: the first processing circuit is configured to measure the capacitance, measure the temperature, and transmit the measured capacitance and the measured temperature to the second processing circuit; and the second processing circuit is configured to determine whether the compression spring is in a compressed state or an extended state based on the transmitted capacitance and the transmitted temperature.

[0102] 3. The drug delivery device according to claim 1, wherein the at least one processing circuit comprises a single processing circuit.

[0103] 4. The drug delivery device according to any one of claims 1 - 3, wherein the temperature sensor and the at least one processing circuit are integrated into a single integrated circuit.

[0104] 5. The drug delivery device according to any one of claims 1-4, wherein the sensing system is configured to wirelessly receive the acquired power from an external power source.

[0105] 6. The drug delivery device according to any one of claims 1-5, wherein the at least one processing circuit is configured to determine that the compression spring is in the compressed state when the measured capacitance is greater than a capacitance threshold, and to determine that the compression spring is in the extended state when the measured capacitance is less than the capacitance threshold.

[0106] 7. The drug delivery device according to claim 6, wherein the at least one processing circuit is configured to adjust the capacitance threshold based on the measured temperature.

[0107] 8. The drug delivery device according to any one of claims 1-7, wherein: the sensing system further includes a wireless communication interface; and the at least one processing circuit is connected to the wireless communication interface and is configured to transmit at least one of the measured capacitance, the measured temperature, and data indicating whether the compression spring is in the compressed state or the extended state to an external device via the wireless communication interface.

[0108] 9. The drug delivery device according to any one of claims 1-8, wherein the first capacitor plate includes a plurality of first finger portions, the second capacitor plate includes a plurality of second finger portions, and the first capacitor plate and the second capacitor plate are arranged such that the plurality of first finger portions are interleaved with the plurality of second finger portions.

[0109] 10. The drug delivery device according to any one of claims 1-9, wherein the at least one processing circuit is configured to be able to determine whether a user's hand is grasping the drug delivery device based on the measured capacitance.

[0110] 11. The drug delivery device according to any one of claims 1-9, further comprising at least a third capacitor plate provided on a user-grippable portion of the drug delivery device, wherein the at least one processing circuit is configured to be able to determine whether a user's hand is grasping the drug delivery device based on the capacitance measured by the third capacitor plate.

[0111] 12. The drug delivery device according to any one of claims 1-11, further comprising a drug.

[0112] 13. An injection system, comprising: a housing of a drug delivery device; a syringe assembly at least partially disposed within the housing of the drug delivery device, the syringe assembly including an injection needle and a liquid storage chamber configured to contain a drug; a drive mechanism at least partially disposed within the housing of the drug delivery device, the drive mechanism configured to dispense the drug from the syringe assembly via the injection needle when activated by a user, the drive mechanism including a compression spring configured to transition from a compressed state to an extended state, or from an extended state to a compressed state, after the activation; and a sensing system including: a first capacitor plate and a second capacitor plate configured such that the compression spring is located between at least a portion of the first capacitor plate and at least a portion of the second capacitor plate; a temperature sensor; and at least one processing circuit configured to: measure a capacitance between the first capacitor plate and the second capacitor plate and measure a temperature based on a signal output by the temperature sensor.

[0113] 14. The injection system according to claim 13, wherein the temperature sensor and the at least one processing circuit are integrated into a single integrated circuit.

[0114] 15. The injection system according to any one of claims 13-14, further comprising a wireless communication interface, wherein the at least one processing circuit is configured to transmit the measured capacitance and the measured temperature to an external device via the wireless communication interface to allow the external device to determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

[0115] 16. The injection system according to any one of claims 13-14, wherein the at least one processing circuit is further configured to determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

[0116] 17. The injection system according to claim 16, further comprising a wireless communication interface, wherein the at least one processing circuit is configured to transmit data indicating whether the compression spring is in the compressed state or the extended state to an external device via the wireless communication interface.

[0117] 18. The injection system according to any one of claims 15 and 17, wherein the wireless communication interface includes a near field communication (NFC) circuit.

[0118] 19. The injection system according to any one of claims 13-18, wherein the first capacitor plate, the second capacitor plate, the temperature sensor, and the at least one processing circuit are attached to a label that is fixed to an outer surface of the housing of the drug delivery device.

[0119] 20. The injection system according to any one of claims 13 - 19, wherein the drug delivery device housing defines an injection hole; the syringe assembly is movable between a storage position and an injection position, in the storage position, the injection needle does not extend through the injection hole, and in the injection position, the injection needle extends through the injection hole; and the compression spring is configured to transition from the compressed state to the extended state after the drug delivery device is activated, so as to move the syringe assembly from the injection position to the storage position after the drug has been dispensed.

[0120] 21. The injection system according to any one of claims 13 - 19, wherein the compression spring is configured to transition from the compressed state to the extended state so as to dispense the drug from the liquid storage chamber via the injection needle.

[0121] 22. The injection system according to any one of claims 13 - 21, further comprising a metal shield covering the first capacitor plate and the second capacitor plate.

[0122] 23. The injection system according to any one of claims 13 - 22, wherein the first capacitor plate includes a plurality of first finger portions, the second capacitor plate includes a plurality of second finger portions, and the first capacitor plate and the second capacitor plate are arranged such that the plurality of first finger portions are interleaved with the plurality of second finger portions.

[0123] 24. The injection system according to any one of claims 13 - 23, wherein the at least one processing circuit is configured to determine whether a user's hand is grasping the drug delivery device based on the measured capacitance.

[0124] 25. The injection system according to any one of claims 13 - 23, further comprising at least a third capacitor plate disposed on a user - grippable portion of the drug delivery device, wherein the at least one processing circuit is configured to determine whether a user's hand is grasping the drug delivery device based on the capacitance measured by the third capacitor plate.

[0125] 26. The injection system according to any one of claims 13 - 25, further comprising a drug.

[0126] 27. A method for determining the state of a compression spring located between at least a portion of a first capacitor plate and at least a portion of a second capacitor plate, the method comprising: measuring a temperature using a temperature sensor by a processing circuit; measuring a capacitance between the first capacitor plate and the second capacitor plate by the processing circuit; and determining by the processing circuit whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

[0127] 28. The method according to claim 27, wherein the compression spring is part of a drug delivery device, and the compression spring is configured to transition from a compressed state to an extended state, or from an extended state to a compressed state, after the drug delivery device is activated to dispense a drug.

[0128] 29. The method according to claim 28, wherein the drug delivery device includes a syringe assembly movable between a storage position and an injection position, and the compression spring is configured to be able to transition from a compressed state to an extended state to move the syringe assembly from the injection position to the storage position.

[0129] 30. The method according to any one of claims 28 - 29, further comprising reporting at least one of the measured capacitance, the measured temperature, and data indicating whether the compression spring is in a compressed state or an extended state to an external device via wireless communication.

[0130] 31. The method according to any one of claims 27 - 30, wherein determining whether the compression spring is in a compressed state or an extended state includes: determining a capacitance threshold to be applied based on the measured temperature; determining that the compression spring is in a compressed state when the measured capacitance is greater than the determined capacitance threshold; and determining that the compression spring is in an extended state when the measured capacitance is less than the determined capacitance threshold.

[0131] 32. The method according to claim 31, wherein determining the capacitance threshold to be applied includes determining to apply a first capacitance threshold when the measured temperature is at a first temperature, and applying a second capacitance threshold lower than the first capacitance threshold when the measured temperature is lower than the first temperature.

Claims

1. A drug delivery device having a sensing system for determining the state of a compression spring of the drug delivery device, the sensing system comprising: A first capacitor plate and a second capacitor plate, the first capacitor plate and the second capacitor plate being configured such that the compression spring is located between at least a portion of the first capacitor plate and at least a portion of the second capacitor plate; A temperature sensor; And At least one processing circuit connected to the first capacitor plate, the second capacitor plate, and the temperature sensor, the at least one processing circuit being configured to: Measure the capacitance between the first capacitor plate and the second capacitor plate, Measure the temperature based on a signal output by the temperature sensor, and Determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

2. The drug delivery device according to claim 1, wherein, The at least one processing circuit includes a first processing circuit and a second processing circuit, and wherein: The first processing circuit is configured to measure the capacitance, measure the temperature, and transmit the measured capacitance and the measured temperature to the second processing circuit; and The second processing circuit is configured to determine whether the compression spring is in a compressed state or an extended state based on the transmitted capacitance and the transmitted temperature.

3. The drug delivery device according to claim 1, wherein, The at least one processing circuit includes a single processing circuit.

4. The drug delivery device according to any one of claims 1 - 3, wherein, The temperature sensor and the at least one processing circuit are integrated into a single integrated circuit.

5. The drug delivery device according to any one of claims 1 - 4, wherein, The sensing system is configured to wirelessly receive the acquired power from an external power source.

6. The drug delivery device according to any one of claims 1 - 5, wherein, The at least one processing circuit is configured to determine that the compression spring is in the compressed state when the measured capacitance is greater than a capacitance threshold, and determine that the compression spring is in the extended state when the measured capacitance is less than the capacitance threshold.

7. The drug delivery device according to claim 6, wherein, The at least one processing circuit is configured to adjust the capacitance threshold based on the measured temperature.

8. The drug delivery device according to any one of claims 1 - 7, wherein: The sensing system further includes a wireless communication interface; and The at least one processing circuit is connected to the wireless communication interface and is configured to transmit at least one of the measured capacitance, the measured temperature, and data indicating whether the compression spring is in the compressed state or the extended state to an external device via the wireless communication interface.

9. The drug delivery device according to any one of claims 1 - 8, wherein, The first capacitor plate includes a plurality of first finger portions, the second capacitor plate includes a plurality of second finger portions, and the first capacitor plate and the second capacitor plate are arranged such that the plurality of first finger portions are interleaved with the plurality of second finger portions.

10. The drug delivery device according to any one of claims 1 - 9, wherein, The at least one processing circuit is configured to determine whether a user's hand is grasping the drug delivery device based on the measured capacitance.

11. The drug delivery device according to any one of claims 1 - 9, further comprising at least a third capacitor plate disposed on a user - grippable portion of the drug delivery device, wherein the at least one processing circuit is configured to determine whether a user's hand is gripping the drug delivery device based on a capacitance measured by the third capacitor plate.

12. The drug delivery device according to any one of claims 1 - 11, further comprising a drug.

13. An injection system, comprising: A drug delivery device housing; A syringe assembly at least partially disposed within the drug delivery device housing, the syringe assembly including a syringe needle and a liquid reservoir configured to contain a drug; A drive mechanism at least partially disposed within the drug delivery device housing, the drive mechanism being configured to dispense the drug from the syringe assembly via the syringe needle when activated by a user, the drive mechanism including a compression spring configured to transition from a compressed state to an extended state, or from an extended state to a compressed state, after the activation; And A sensing system, the sensing system including: A first capacitor plate and a second capacitor plate, the first capacitor plate and the second capacitor plate being configured such that the compression spring is located between at least a portion of the first capacitor plate and at least a portion of the second capacitor plate; A temperature sensor, and At least one processing circuit configured to: Measure the capacitance between the first capacitor plate and the second capacitor plate, and Measure the temperature based on a signal output by the temperature sensor.

14. The injection system according to claim 13, wherein, The temperature sensor and the at least one processing circuit are integrated into a single integrated circuit.

15. The injection system according to any one of claims 13 - 14, further comprising a wireless communication interface, wherein the at least one processing circuit is configured to transmit the measured capacitance and the measured temperature to an external device via the wireless communication interface to allow the external device to determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

16. The injection system according to any one of claims 13 - 14, wherein, The at least one processing circuit is further configured to determine whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

17. The injection system according to claim 16, further comprising a wireless communication interface, wherein, The at least one processing circuit is configured to transmit data indicating whether the compression spring is in the compressed state or the extended state to an external device via the wireless communication interface.

18. The injection system according to any one of claims 15 and 17, wherein, The wireless communication interface includes a near field communication (NFC) circuit.

19. The injection system according to any one of claims 13 - 18, wherein, The first capacitor plate, the second capacitor plate, the temperature sensor and the at least one processing circuit are attached to a tag, the tag being fixed to an outer surface of the drug delivery device housing.

20. The injection system according to any one of claims 13 - 19, wherein: The drug delivery device housing defines an injection hole; The syringe assembly is movable between a storage position and an injection position, in the storage position, the injection needle does not extend through the injection hole, and in the injection position, the injection needle extends through the injection hole; And The compression spring is configured to transition from a compressed state to an extended state after the drug delivery device is activated, so as to move the syringe assembly from the injection position to the storage position after the drug has been dispensed.

21. The injection system according to any one of claims 13 - 19, wherein, The compression spring is configured to transition from the compressed state to the extended state so as to dispense the drug from the liquid reservoir through the injection needle.

22. The injection system according to any one of claims 13 - 21, further comprising a metal shield covering the first capacitor plate and the second capacitor plate.

23. The injection system according to any one of claims 13 - 22, wherein, The first capacitor plate includes a plurality of first finger portions, the second capacitor plate includes a plurality of second finger portions, and the first capacitor plate and the second capacitor plate are arranged such that the plurality of first finger portions are interleaved with the plurality of second finger portions.

24. The injection system according to any one of claims 13 - 23, wherein, The at least one processing circuit is configured to determine whether a user's hand is grasping the drug delivery device based on the measured capacitance.

25. The injection system according to any one of claims 13 - 23 further comprises at least a third capacitor plate disposed on a user - grippable portion of the drug delivery device, wherein the at least one processing circuit is configured to determine whether a user's hand is gripping the drug delivery device based on the capacitance measured by the third capacitor plate.

26. The injection system according to any one of claims 13 - 25 further comprises a drug.

27. A method for determining the state of a compression spring located between at least a portion of a first capacitor plate and at least a portion of a second capacitor plate, the method comprising: Measuring the temperature by the processing circuit using the temperature sensor; Measuring the capacitance between the first capacitor plate and the second capacitor plate by the processing circuit; And Determining by the processing circuit whether the compression spring is in a compressed state or an extended state based on the measured capacitance and the measured temperature.

28. The method according to claim 27, wherein, The compression spring is part of the drug delivery device and is configured to transition from the compressed state to the extended state, or from the extended state to the compressed state, after the drug delivery device is activated to dispense the drug.

29. The method according to claim 28, wherein, The drug delivery device includes a syringe assembly movable between a storage position and an injection position, and the compression spring is configured to be able to transition from the compressed state to the extended state so as to move the syringe assembly from the injection position to the storage position.

30. The method according to any one of claims 28 - 29 further comprises reporting at least one of the measured capacitance, the measured temperature, and data indicating whether the compression spring is in the compressed state or the extended state to an external device via wireless communication.

31. The method according to any one of claims 27 - 30, wherein, Determining whether the compression spring is in the compressed state or the extended state includes: Determine a capacitance threshold to be applied based on the measured temperature; When the measured capacitance is greater than the determined capacitance threshold, determine that the compression spring is in the compressed state; and When the measured capacitance is less than the determined capacitance threshold, determine that the compression spring is in the extended state.

32. The method according to claim 31, wherein, Determining the capacitance threshold to be applied includes determining to apply a first capacitance threshold when the measured temperature is at a first temperature, and a second capacitance threshold lower than the first capacitance threshold when the measured temperature is lower than the first temperature.

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