WO2023233568A1 - Dispositif et procédé d'analyse de transpiration - Google Patents

Dispositif et procédé d'analyse de transpiration Download PDF

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Publication number
WO2023233568A1
WO2023233568A1 PCT/JP2022/022267 JP2022022267W WO2023233568A1 WO 2023233568 A1 WO2023233568 A1 WO 2023233568A1 JP 2022022267 W JP2022022267 W JP 2022022267W WO 2023233568 A1 WO2023233568 A1 WO 2023233568A1
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Prior art keywords
sweat
amount
wearer
electrolyte concentration
value
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PCT/JP2022/022267
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English (en)
Japanese (ja)
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優生 橋本
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日本電信電話株式会社
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Priority to PCT/JP2022/022267 priority Critical patent/WO2023233568A1/fr
Publication of WO2023233568A1 publication Critical patent/WO2023233568A1/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons

Definitions

  • the present invention relates to a sweat analysis device and method that are attached to the human body and measure the sweat amount and sweat electrolyte concentration of the wearer.
  • Non-Patent Document 1 Due to global warming, the number of heat waves is increasing in most regions of the world. In recent years, the incidence of heat stroke has increased in Japan as the frequency of extreme heat waves has increased. The number of people transported to the hospital due to heat stroke has remained at a high level since its peak in 2018, and has become a social problem (see Non-Patent Document 1).
  • Heatstroke refers to a state of multiple organ failure caused by high temperatures or intense exercise. Generally, a person's body temperature is maintained at about 37° C. through the process of thermoregulation by the anterior hypothalamus. The physical phenomena associated with sweating, such as evaporation, heat radiation, convection, and conduction, function to cool the body surface.
  • FIG. 11 is a cross-sectional view of the wearable sensor disclosed in Patent Document 1
  • FIG. 12 is an enlarged view of FIG. 11.
  • the wearable sensor 1 includes a base material 10 having a through hole 11 that serves as a liquid flow path, a recess 12 that communicates with an end of the through hole 11 on the exit side, and a base material that has an end of the through hole 11 on the inlet side open.
  • 13 is a recess formed on the lower surface of the base material 10
  • 100 is the skin of the wearer of the wearable sensor 1
  • 101 is the sweat gland of the wearer.
  • the amount of sweat of the wearer of the wearable sensor 1 and the electrolyte concentration in the sweat can be calculated based on the current conduction characteristics between the electrodes 14 and 16 due to the sweat 102 flowing out from the through hole 11 into the recess 12. can do.
  • FIG. 13 is a cross-sectional view of the wearable sensor disclosed in Patent Document 2, and FIG. 14 is an enlarged view of FIG. 13.
  • the wearable sensor 1a is arranged in a base material 10 having a through hole 11 and a recess 12, a water absorbing structure 15, and within the recess 12, and is arranged along the exit side surface of the base material 10 on the exit side of the through hole 11.
  • a laser diode (LD) 18 that emits light onto a path within the recess 12 that passes through a position above the opening
  • LD laser diode
  • PD photodiode
  • Reference numeral 103 in FIG. 13 indicates light emitted from the LD 18.
  • the wearable sensor 1a By using the wearable sensor 1a, it is possible to calculate the sweat amount and electrolyte concentration in the sweat of the wearer of the wearable sensor 1a based on the light receiving characteristics of the PD 19 that receives light from the LD 18.
  • the present invention has been made to solve the above problems, and is a sweat analysis device and method that can reduce measurement errors in sweat amount and electrolyte concentration by making corrections taking into account the effects of sweat evaporation.
  • the purpose is to provide
  • the sweat analysis device of the present invention includes a wearable sensor configured to output an electrical signal derived from the amount of sweat secreted from the wearer's skin and the electrolyte concentration; a temperature sensor configured to measure the temperature of an internal space of the wearable sensor; a humidity sensor configured to measure the relative humidity of the internal space of the wearable sensor into which sweat of the wearer flows; a sweat amount calculation section configured to calculate a measured sweat amount of the wearer based on the electrical signal obtained by the sensor; an electrolyte concentration calculation unit configured to calculate an electrolyte concentration measurement value based on a known physical quantity related to sweat evaporation, the sweat amount measurement value, the electrolyte concentration measurement value, the temperature, and the relative humidity.
  • the present invention is characterized by comprising a correction section configured to calculate a true value of sweat amount and a true value of electrolyte concentration after correcting the influence of sweat loss due to evaporation.
  • a wearable sensor a temperature sensor, a humidity sensor, a sweat amount calculation section, an electrolyte concentration calculation section, and a correction section are provided, and the true value of sweat amount and electrolyte concentration corrected for the influence of sweat loss due to evaporation are calculated.
  • the true value By calculating the true value by the correction unit, it is possible to reduce the possibility of underestimating the sweat amount or overestimating the electrolyte concentration. As a result, in the present invention, highly accurate measurement of sweat amount and electrolyte concentration can be realized.
  • FIG. 1 is a diagram showing an example of a change in the value of current flowing between electrodes, measured by a wearable sensor.
  • FIG. 2 is a block diagram showing the configuration of a sweat analysis device according to the first embodiment of the present invention.
  • FIG. 3 is a functional block diagram of the MCU section of the sweat analysis device according to the first embodiment of the present invention.
  • FIG. 4 is a flowchart illustrating the operation of the sweat analysis device according to the first embodiment of the present invention.
  • FIG. 5 is a flowchart illustrating the operation of the correction section of the sweat analysis device according to the first embodiment of the present invention.
  • FIG. 6 is a flowchart illustrating the operation of the correction section of the sweat analysis device according to the second embodiment of the present invention.
  • FIG. 1 is a diagram showing an example of a change in the value of current flowing between electrodes, measured by a wearable sensor.
  • FIG. 2 is a block diagram showing the configuration of a sweat analysis device according to the first embodiment of the present invention.
  • FIG. 7 is a flowchart illustrating the operation of the correction section of the sweat analysis device according to the third embodiment of the present invention.
  • FIG. 8 is a block diagram showing the configuration of a sweat analysis device according to a fourth embodiment of the present invention.
  • FIG. 9 is a functional block diagram of the MCU section of the sweat analysis device according to the fourth embodiment of the present invention.
  • FIG. 10 is a block diagram showing an example of the configuration of a computer that implements the sweat analysis apparatus according to the first to fourth embodiments of the present invention.
  • FIG. 11 is a cross-sectional view of a conventional wearable sensor.
  • FIG. 12 is an enlarged cross-sectional view of a conventional wearable sensor.
  • FIG. 13 is a cross-sectional view of another conventional wearable sensor.
  • FIG. 14 is an enlarged sectional view of another conventional wearable sensor.
  • the sweat amount and electrolyte concentration in sweat of a wearable sensor wearer are measured by the sweat analysis device disclosed in Patent Documents 1 and 2.
  • the measured value of the sweat amount of the wearer is Q [L/s]
  • the true value of the sweat amount is Q' [L/s]
  • the measured value of the electrolyte concentration in the wearer's sweat is C [mol/L]
  • the electrolyte It is assumed that the true value of the concentration is C' [mol/L]
  • the temperature of the internal space of the wearable sensor into which the wearer's sweat flows is T [°C]
  • the relative humidity of the internal space is RH [%].
  • the true value Q' of sweat amount and the true value C' of electrolyte concentration can be calculated as shown in equations (1) to (5).
  • equation (1) means that the true value Q' of the amount of sweat is determined by adding the amount of sweat loss due to evaporation to the measured amount of sweat Q.
  • " ⁇ " in equation (3) means exponentiation.
  • D [m 2 /s] is the diffusion coefficient of water vapor in sweat when the measured electrolyte concentration is C
  • ⁇ C [kg/m 3 ] is the sweat liquid generated at the opening of the through hole 11 in FIGS. 11 to 14.
  • r [m] is 1/2 of the dimension of the opening of the through hole 11 (the diameter if the cross section of the opening is circular), and ⁇ c [rad] is the distance between the surface of the electrode 16 or the surface of the water absorption structure 15 and the sweat
  • P s [Pa] is the saturated water vapor pressure.
  • the water density ⁇ , the value r that is half the size of the opening of the through hole 11, and the static contact angle ⁇ c are known physical quantities related to the evaporation of sweat.
  • Equation (6) is an equation for the time differentiation of the dynamic contact angle ⁇ [rad] in a state where the sweat droplet 102a changes continuously after it lands on the electrode 16 or the water absorbing structure 15.
  • T c [s] is the measured value of the period of the upward peak of the current flowing between electrodes 14 and 16 in FIG. 11, or the measured value of the period of the downward peak of the photocurrent flowing through PD 19 in FIG. 13.
  • Equation (7) is an equation for integrating the amount of sweat loss due to evaporation during the period Tc .
  • FIG. 1 shows an example of a change in the value of the current flowing between the electrodes, which is measured by the wearable sensor disclosed in Patent Document 1.
  • the current continues to flow while the sweat droplet 102a exists between the electrodes 14 and 16, and the flow rate of sweat flowing into the wearable sensor increases.
  • the cycle of energization changes depending on the amount of perspiration, and the peak current during energization changes depending on the electrolyte concentration.
  • ⁇ (t) be the dynamic contact angle ⁇ of the sweat droplet 102a at time t.
  • the estimated value of the true value Q' of the sweat amount a value within the range of the measured sweat amount Q or more and less than the predetermined sweat amount value is set, and the following equations (8) and (9) are set. Do calculations.
  • the predetermined value of the amount of perspiration mentioned above is the amount of perspiration at which the influence of evaporation can be ignored, or the upper limit value Q max of the amount of perspiration.
  • the upper limit value Q max may be set in advance to an actual value based on the results obtained in past measurements.
  • formula (8) and formula (9) are calculated for each estimated value of the true value Q'. Do calculations. Then, the estimated value that minimizes the square f(Q') 2 of the evaluation function f(Q') calculated for each estimated value of the true value Q' is set as the true value Q' of the sweat amount. Furthermore, the true value C' of the electrolyte concentration is calculated using equation (5).
  • FIG. 2 is a block diagram showing the configuration of a sweat analysis device according to the first embodiment of the present invention.
  • the sweat analysis device includes a wearable sensor 1, a temperature sensor 2, a humidity sensor 3, an AFE (Analog Front End) section 4, a data recording section 5, a storage section 6, and an MCU (Micro Control Unit) section 7. , a communication section 8, and a power supply section 9.
  • AFE Analog Front End
  • MCU Micro Control Unit
  • Wearable sensor 1 outputs an electrical signal (for example, a current having the waveform shown in FIG. 1) derived from the amount of sweat secreted from the wearer's skin and the electrolyte concentration.
  • the temperature sensor 2 measures the temperature T of the internal space of the wearable sensor 1 into which sweat secreted from the wearer's skin flows.
  • the humidity sensor 3 measures the relative humidity RH of the internal space of the wearable sensor 1 into which sweat secreted from the wearer's skin flows.
  • the temperature sensor 2 and the humidity sensor 3 may be integrated.
  • the AFE section 4 includes an analog front end and amplifies the weak electrical signal output from the wearable sensor 1.
  • the data recording section 5 includes an ADC (Analog Digital Converter), converts the analog signal amplified by the AFE section 4 into digital data at a predetermined sampling frequency, and stores the digital data in the storage section 6 .
  • ADC Analog Digital Converter
  • the storage unit 6 stores digital data output from the data recording unit 5.
  • the storage unit 6 is realized by a nonvolatile memory such as a flash memory, a volatile memory such as a DRAM (Dynamic Random Access Memory), or the like.
  • the MCU unit 7 is a circuit that performs signal processing to calculate sweat amount and electrolyte concentration from digital data stored in the storage unit 6.
  • the communication unit 8 includes a circuit that transmits the measurement results and analysis results obtained by the MCU unit 7 to an external device (not shown) such as a smartphone wirelessly or by wire.
  • wireless communication standards include BLE (Bluetooth (registered trademark) Low Energy).
  • wired communication there is, for example, Ethernet (registered trademark).
  • the power supply unit 9 is a circuit that plays the role of supplying power to the sweat analysis device.
  • the wearable sensor 1 includes a base material 10 having a through hole 11 and a recess 12 that communicates with the end of the outlet side of the through hole 11, and a surface of the base material 10 where the end of the inlet side of the through hole 11 is open.
  • a water-absorbing structure 15 disposed on the exit-side surface (upper surface) of the base material 10 so as to be in contact with the liquid flowing out from the exit-side opening of the through-hole 11 into the recess 12;
  • a water-absorbing electrode 16 is provided on the surface of 15 facing the base material 10 so as to face the opening on the exit side of the through hole 11.
  • the base material 10 may be made of, for example, a hydrophilic glass material or a resin material.
  • the base material 10 may also be made of a water-repellent material whose surface and the inner surface of the through hole 11 have been subjected to surface treatment to impart hydrophilicity.
  • a recess 12 having a depressed upper surface is formed on the upper surface of the base material 10 so as to communicate with the through hole 11 .
  • a recess 13 having a concave lower surface is formed on the lower surface of the base material 10 so as to communicate with the through hole 11 .
  • the electrode 14 is made of, for example, a metal thin film formed on the surface (lower surface) of the base material 10 where the end on the entrance side of the through hole 11 is open.
  • Examples of the water absorbing structure 15 include fibers such as cotton and silk, and porous ceramic substrates.
  • Examples of the electrode 16 include a porous metal thin film formed on the surface of the water absorbing structure 15 by plating technology, a conductive polymer impregnated into the fibers of the water absorbing structure 15, and a conductive fiber woven together. etc. can be mentioned.
  • Wearable sensor 1 is worn on the wearer's body so that the lower surface of base material 10 faces skin 100 of the wearer, as shown in FIG.
  • Reference numeral 101 in FIG. 11 indicates the wearer's sweat glands.
  • the sweat 102 is introduced into the through hole 11 from the recess 13 of the base material 10 due to capillary action. Further, due to an increase in the amount of perspiration, the sweat 102 rises inside the through hole 11 and reaches the recess 12 .
  • a water-repellent portion 17 is provided on the inner surface of the recess 12.
  • the water-repellent portion 17 may be formed by subjecting the inner surface of the recess 12 to a water-repellent surface treatment.
  • the water-repellent portion 17 can be provided by leaving only the inner surface of the recess 12 made of the water-repellent material.
  • the sweat 102 When the sweat 102 reaches the recess 12, which is the internal space of the wearable sensor 1, it becomes a spherical droplet 102a as shown in FIG. 12. Further, as the amount of perspiration increases, the droplet 102a increases in diameter and finally reaches the electrode 16 and the water absorbing structure 15. The droplet 102a that has reached the electrode 16 and the water-absorbing structure 15 evaporates while moving within the water-absorbing structure 15 through the many holes of the electrode 16 and the many holes of the water-absorbing structure 15 due to capillarity. As a result, the droplet 102a disappears. In this way, energization between the electrodes 14 and 16 of the wearable sensor 1 repeatedly occurs due to the formation and disappearance of the droplet 102a.
  • the temperature sensor 2 measures the temperature T of the atmosphere filling the recess 12 of the wearable sensor 1.
  • the humidity sensor 3 measures the relative humidity RH within the recess 12. Specifically, the temperature sensor 2 and the humidity sensor 3 are installed near the electrode 16 or near the water absorption structure 15 in FIGS. 11 and 12.
  • the structure of the wearable sensor 1 is described using the structures of FIGS. 11 and 12 as examples, but the structure is not limited to this. Wearable sensors with other structures may be used as long as current flows intermittently between the electrodes due to droplets that are intermittently generated within the wearable sensor due to sweating of the wearer.
  • FIG. 3 is a functional block diagram of the MCU section 7 of this embodiment.
  • the MCU section 7 functions as a sweat amount calculation section 70, an electrolyte concentration calculation section 71, and a correction section 72.
  • the sweat amount calculation unit 70 calculates a measured value Q of the wearer's sweat amount based on the current conduction characteristics between the electrodes of the wearable sensor 1.
  • the electrolyte concentration calculation unit 71 calculates a measured value C of the electrolyte concentration in the wearer's sweat based on the current conduction characteristics between the electrodes of the wearable sensor 1.
  • the correction unit 72 calculates the amount of sweat caused by evaporation based on known physical quantities related to the evaporation of sweat, a measured value Q of perspiration amount, a measured value C of electrolyte concentration, a measured value T of temperature, and a measured value RH of relative humidity. The true value Q' of sweat amount and the true value C' of electrolyte concentration corrected for the influence of weight loss are calculated.
  • FIG. 4 is a flowchart illustrating the operation of the sweat analysis device of this embodiment.
  • the AFE unit 4 detects the current flowing between the electrodes 14 and 16 of the wearable sensor 1 (step S1 in FIG. 4).
  • the AFE unit 4 also receives a signal indicating the temperature T from the temperature sensor 2 (step S2 in FIG. 4), and receives a signal indicating the relative humidity RH from the humidity sensor 3 (step S3 in FIG. 4).
  • the data recording unit 5 converts the signal amplified by the AFE unit 4 into digital data at a predetermined sampling rate (step S4 in FIG. 4), and stores it in the storage unit 6 (step S5 in FIG. 4). At this time, the data recording section 5 adds sampling time information to the digital data and stores it in the storage section 6. In this way, the storage unit 6 stores time-series data of the current, temperature T, and relative humidity RH.
  • the sweat amount calculation unit 70 calculates the measured value Q [L/s] of the sweat amount of the wearer of the wearable sensor 1 based on the digital data stored in the storage unit 6 (step S6 in FIG. 4). Specifically, the sweat amount calculation unit 70 calculates the sweat amount by dividing the volume V [L] of the sweat droplet 102a by the cycle T c [s] from the immediately previous current peak to the latest current peak. The measured value Q [L/s] can be calculated.
  • the volume V of the sweat droplet 102a generated between the electrodes 14 and 16 of the wearable sensor 1 can be determined in advance to an actual value.
  • the electrolyte concentration calculation unit 71 calculates the electrical resistivity R ⁇ of sweat that changes depending on the electrolyte concentration C [mol/L] in the wearer's sweat, and calculates the measured value C [of the electrolyte concentration in sweat] from this electrical resistivity R ⁇ . mol/L] (step S7 in FIG. 4).
  • the electrolyte concentration calculation section 71 converts the value of the known voltage applied by the AFE section 4 between the electrodes 14 and 16 into the current peak value at the latest energization indicated by the digital data stored in the storage section 6. Calculate the resistance by dividing by Then, the electrolyte concentration calculation unit 71 calculates the electrical resistivity R ⁇ based on the resistance value, the known distance between the electrodes 14 and 16, and the cross-sectional area of sweat between the electrodes 14 and 16. Regarding the cross-sectional area of sweat, a prescribed value may be used assuming that the cross-sectional area of sweat between electrodes 14 and 16 is constant.
  • the electrolyte concentration calculation unit 71 calculates the measured value C [mol/L] of the electrolyte concentration from the electrical resistivity R ⁇ based on the known relationship between the electrical resistivity R ⁇ and the electrolyte concentration C.
  • FIG. 5 is a flowchart illustrating the operation of the correction section 72.
  • the correction unit 72 calculates the measured value Q of sweat amount, the measured value T of temperature, the measured value RH of relative humidity, the density ⁇ of water, and the dimension of the opening of the through hole 11 (the cross section of the opening is circular). Based on the value r, which is 1/2 of the diameter) and the known static contact angle ⁇ c of the droplet 102a, the true value Q' of the sweat amount corrected for the influence of sweat loss due to evaporation is calculated using the formula ( 1) to equation (4) (step S100 in FIG. 5).
  • the static contact angle ⁇ c may be set, for example, to a value determined through prior experiments.
  • the correction unit 72 corrects the influence of sweat loss due to evaporation based on the true value Q' of the sweat amount, the measured value Q of the sweat amount, and the measured value C of the electrolyte concentration, and corrects the true value C' of the electrolyte concentration. is calculated using equation (5) (step S101 in FIG. 5).
  • the communication unit 8 transmits the calculation result of the sweat amount calculation unit 70, the calculation result of the electrolyte concentration calculation unit 71, and the correction result of the correction unit 72 to an external device (not shown) such as a smartphone (step S9 in FIG. 4).
  • the sweat analysis device repeatedly executes the processes of steps S1 to S9 until, for example, the wearer issues an instruction to end the measurement (YES in step S10 in FIG. 4).
  • the true value of the sweat amount and the true value of the electrolyte concentration can be calculated. It is possible to reduce the possibility of underestimating the sweat amount or overestimating the electrolyte concentration.
  • the correction unit 72 calculates a measured value Q of perspiration amount, a measured value T of temperature, a measured value RH of relative humidity, a density ⁇ of water, and a value r which is 1/2 of the dimension of the opening of the through hole 11.
  • equation (6) for the time differential of the dynamic contact angle ⁇ of the sweat droplet 102a and the period T
  • the true value Q' of the sweat amount is calculated by solving equation (7) for the integral of the sweat loss due to evaporation during the period c for Q' (step S200 in FIG. 6).
  • the difference in water vapor density ⁇ C can be calculated using equations (2) and (3)
  • the water vapor diffusion coefficient D can be calculated using equation (4).
  • the correction unit 72 calculates the true value C' of the electrolyte concentration using equation (5) based on the true value Q' of the sweat amount, the measured value Q of the sweat amount, and the measured value C of the electrolyte concentration (Fig. 6 step S201).
  • the other configuration of the sweat analysis device is the same as the first embodiment.
  • the correction unit 72 calculates the initial value ⁇ (0) of the dynamic contact angle, the estimated value of the true value Q' of the sweat amount, the measured value T of the temperature, the measured value RH of the relative humidity, and the density ⁇ of water. , and the value r that is half the size of the opening of the through hole 11 .
  • the dynamic contact angle ⁇ is calculated at each calculation interval ⁇ t using equation (8) (step S302 in FIG. 7).
  • the difference in water vapor density ⁇ C can be calculated using equations (2) and (3), and the water vapor diffusion coefficient D can be calculated using equation (4).
  • the correction unit 72 If the correction unit 72 has not completed the calculation processing in steps S302 and S303 for all of the estimated values of the true value Q' of the sweat amount (NO in step S304 in FIG. 7), the correction unit 72 returns to step S301 and calculates the true value Q of the sweat amount. ' change the estimate of '. As described above, the correction unit 72 changes the estimated value by a predetermined step width of the sweat amount. In this way, the correction unit 72 calculates the evaluation function f(Q') for each of the plurality of estimated values of the true value Q' of the sweat amount.
  • the correction unit 72 adjusts the estimated value starting from the sweat amount measured value Q to a predetermined sweat amount predetermined value (for example, an upper limit When Q max ) is reached, it is determined that the calculation processing in steps S302 and S303 has ended.
  • a predetermined sweat amount predetermined value for example, an upper limit When Q max ) is reached
  • the correction unit 72 uses the estimated value that yields the best evaluation function f(Q') as the true value of the sweat amount. It is determined as Q' (step S305 in FIG. 7). Specifically, the correction unit 72 sets the estimated value that minimizes the square f(Q') 2 of the evaluation function f(Q') as the true value Q' of the sweat amount.
  • the correction unit 72 calculates the true value C' of the electrolyte concentration using equation (5) based on the true value Q' of the sweat amount, the measured value Q of the sweat amount, and the measured value C of the electrolyte concentration (Fig. 7 step S306).
  • the other configuration of the sweat analysis device is the same as the first embodiment.
  • FIG. 8 is a block diagram showing the configuration of a sweat analysis device according to a fourth embodiment of the present invention.
  • the sweat analysis device includes a wearable sensor 1a, a temperature sensor 2, a humidity sensor 3, an AFE section 4, a data recording section 5, a storage section 6, an MCU section 7a, a communication section 8, and a power supply section 9. It is equipped with
  • the wearable sensor 1a in this embodiment is the same as that disclosed in Patent Document 2, the structure of the wearable sensor 1a will be explained using FIGS. 13 and 14.
  • the wearable sensor 1a is arranged in a base material 10 having a through hole 11 and a recess 12, a water absorbing structure 15, and within the recess 12, and is arranged along the exit side surface of the base material 10 on the exit side of the through hole 11.
  • An LD 18 that emits light onto a path within the recess 12 that passes through a position above the opening, and an LD 18 that is arranged in the recess 12 to face the LD 18 across the position above the opening on the exit side of the through hole 11, and emits light from the LD 18.
  • It is equipped with a PD 19 that receives light.
  • Examples of the water absorbing structure 15 include fibers such as cotton and silk, and porous ceramic substrates. Note that the water absorption structure 15 does not need to cover the entire surface of the opening on the exit side of the through hole 11 and the recess 12, and is arranged so that it can come into contact with the droplets flowing out from the opening on the exit side of the through hole 11 into the recess 12. All you have to do is stay there.
  • Wearable sensor 1a is worn on the wearer's body so that the lower surface of base material 10 faces skin 100 of the wearer, as shown in FIG.
  • the sweat 102 is introduced into the through hole 11 from the recess 13 of the base material 10 due to capillary action. Further, due to an increase in the amount of perspiration, the sweat 102 rises inside the through hole 11 and reaches the recess 12 provided on the upper surface of the base material 10 so as to communicate with the through hole 11.
  • a water-repellent portion 17 is provided on the inner surface of the recess 12.
  • the recess 12 which is the internal space of the wearable sensor 1a
  • the droplet 102a increases in diameter and finally reaches the water absorbing structure 15.
  • the droplets 102a that have reached the water-absorbing structure 15 evaporate while moving inside the water-absorbing structure 15 through a large number of holes in the water-absorbing structure 15 due to capillarity. As a result, the droplet 102a disappears.
  • the LD 18, which is a light emitting element is inserted into a recess that passes through a position above the exit side opening of the through hole 11 along the exit side surface (upper surface) of the base material 10, as shown in FIGS. 13 and 14.
  • the light is emitted to a path within 12.
  • PD19 which is a light receiving element, receives light from LD18.
  • the light 103 emitted from the LD 18 propagates through each medium in the order of air in the recess 12, droplet 102a, and air in the recess 12, and enters the PD 19.
  • the droplet 102a disappears, the light 103 propagates through the air within the recess 12 and enters the PD 19.
  • the droplet 102a is formed again, the light 103 propagates through each medium in the order of air in the recess 12, droplet 102a, and air in the recess 12, and enters the PD 19. In this way, the difference in the medium through which the light 103 propagates is reflected in the amount of light received by the PD 19. That is, the photocurrent flowing through the PD 19 changes due to the formation and disappearance of the droplet 102a.
  • the temperature sensor 2 measures the temperature T of the atmosphere filling the recess 12 of the wearable sensor 1a.
  • the humidity sensor 3 measures the relative humidity RH within the recess 12.
  • the configurations of the AFE section 4, data recording section 5, storage section 6, communication section 8, and power supply section 9 of the sweat analysis device are the same as in the first embodiment.
  • the AFE unit 4 may amplify the output signal (photocurrent) of the PD 19, the signal indicating the temperature T, and the signal indicating the relative humidity RH.
  • FIG. 9 is a functional block diagram of the MCU unit 7a of this embodiment.
  • the MCU section 7a functions as a sweat amount calculation section 70a, an electrolyte concentration calculation section 71a, and a correction section 72a.
  • the sweat amount calculation unit 70a calculates the measured value Q of the wearer's sweat amount based on the light receiving characteristics of the PD 19.
  • the electrolyte concentration calculation unit 71a calculates the measured value C of the electrolyte concentration in the wearer's sweat based on the light receiving characteristics of the PD 19.
  • the correction unit 72a calculates the amount of sweat caused by evaporation based on known physical quantities related to sweat evaporation, a measured value Q of perspiration amount, a measured value C of electrolyte concentration, a measured value T of temperature, and a measured value RH of relative humidity. The true value Q' of sweat amount and the true value C' of electrolyte concentration corrected for the influence of weight loss are calculated.
  • the AFE unit 4 detects the photocurrent of the PD 19 of the wearable sensor 1a (step S1 in FIG. 4).
  • the AFE unit 4 also receives a signal indicating the temperature T from the temperature sensor 2 (step S2 in FIG. 4), and receives a signal indicating the relative humidity RH from the humidity sensor 3 (step S3 in FIG. 4).
  • the data recording unit 5 converts the signal amplified by the AFE unit 4 into digital data at a predetermined sampling rate (step S4 in FIG. 4), and stores it in the storage unit 6 (step S5 in FIG. 4).
  • the sweat amount calculation unit 70a calculates the measured value Q of the sweat amount of the wearer of the wearable sensor 1a based on the digital data stored in the storage unit 6 (step S6 in FIG. 4). Specifically, the sweat amount calculation unit 70a calculates the measured value Q of the sweat amount by dividing the volume V of the sweat droplet 102a by the cycle T c from the immediately previous current peak to the latest current peak. do.
  • the sweat amount calculation unit 70a calculates the measured value Q of the sweat amount using the period Tc of the downward peak of the photocurrent of the PD 19.
  • the electrolyte concentration calculation unit 71a calculates the measured value C of the electrolyte concentration in the wearer's sweat based on the amount of light received by the PD 19 (step S7 in FIG. 4).
  • the laser wavelength of the LD 18 is set to the absorption wavelength of a specific component in sweat.
  • the electrolyte concentration calculation unit 71a can calculate the measured value C of the electrolyte concentration based on the amount of light received by the PD 19 when the value reaches the minimum value.
  • the correction unit 72a corrects the measured value Q of sweat amount calculated by the sweat amount calculation unit 70a and the measured value C of the electrolyte concentration calculated by the electrolyte concentration calculation unit 71a (step S8 in FIG. 4). In this embodiment, correction is performed using the first correction method.
  • the operation of the correction section 72a is the same as that of the correction section 72 of the first embodiment.
  • the communication unit 8 transmits the calculation result of the sweat amount calculation unit 70a, the calculation result of the electrolyte concentration calculation unit 71a, and the correction result of the correction unit 72a to an external device such as a smartphone (step S9 in FIG. 4).
  • the sweat analysis device repeatedly executes the processes of steps S1 to S9 until receiving an instruction from the wearer to end the measurement (YES in step S10 in FIG. 4). In this way, in this embodiment, as in the first embodiment, it is possible to reduce the possibility of underestimating the amount of perspiration or overestimating the electrolyte concentration.
  • the amount of perspiration and the electrolyte concentration are corrected based on the first correction method, but the correction may be performed based on the second correction method.
  • the operation of the correction section 72a is similar to that of the correction section 72 of the second embodiment.
  • the difference from the correction unit 72 is that the correction unit 72a uses the period Tc of the downward peak of the photocurrent of the PD 19 instead of the period of the peak of the current flowing between the electrodes 14 and 16. ' is calculated.
  • the amount of perspiration and the electrolyte concentration may be corrected based on the third correction method.
  • the operation of the correction section 72a is similar to that of the correction section 72 of the third embodiment.
  • the difference from the correction unit 72 is that the correction unit 72a uses the evaluation function f (Q' ) is calculated.
  • the data recording unit 5, storage unit 6, MCU units 7, 7a, and communication unit 8 described in the first to fourth embodiments are a computer equipped with a CPU (Central Processing Unit), a storage device, and an interface, and these components. This can be realized by a program that controls hardware resources. An example of the configuration of this computer is shown in FIG.
  • the computer includes a CPU 200, a storage device 201, and an interface device (I/F) 202.
  • the I/F 202 is connected to hardware such as the ADC of the data recording section 5, hardware of the communication section 8, and the like.
  • a program for realizing the sweat analysis method of the present invention is stored in the storage device 201.
  • the CPU 200 executes the processes described in the first to fourth embodiments according to the program stored in the storage device 201.
  • the sweat analysis device of the present invention includes a wearable sensor configured to output an electrical signal derived from the sweat amount and electrolyte concentration of sweat secreted from the skin of a wearer, and a temperature sensor configured to measure the temperature of the internal space of the wearable sensor into which sweat of the wearer flows; and a humidity sensor configured to measure the relative humidity of the internal space of the wearable sensor into which sweat of the wearer flows.
  • a perspiration amount calculation unit configured to calculate a measured sweat amount of the wearer based on the electrical signal obtained by the wearable sensor; an electrolyte concentration calculation unit configured to calculate a measured value of electrolyte concentration in sweat of a person; a known physical quantity related to sweat evaporation; the measured sweat amount; the measured electrolyte concentration; the temperature;
  • the present invention is characterized by comprising a correction unit configured to calculate a true value of sweat amount and a true value of electrolyte concentration based on the humidity and the effect of sweat loss due to evaporation.
  • the correction unit calculates the amount of sweat loss due to evaporation based on the known physical quantities related to sweat evaporation, the temperature, and the relative humidity, and A value obtained by adding the sweat loss amount to the sweat amount measurement value is calculated as the true value of the sweat amount, and the electrolyte concentration is calculated based on the true value of the sweat amount, the sweat amount measurement value, and the electrolyte concentration measurement value. Calculate the true value.
  • the electrical signal is a current that changes due to droplets intermittently generated in the internal space of the wearable sensor due to sweating of the wearer
  • the sweat amount calculation unit calculates the sweat amount measurement value of the wearer based on the period of the peak of the current, and the correction unit calculates a sweat amount measurement value of the wearer based on a known physical quantity related to sweat evaporation, the sweat amount measurement value, the temperature, and the relative humidity.
  • the electrical signal is a current that changes due to droplets that are intermittently generated in the internal space of the wearable sensor due to sweating of the wearer
  • the sweat amount calculation unit is , the correction unit calculates a measured sweat amount of the wearer based on the period of the peak of the current, and the correction unit sets a plurality of estimated values of the true value of the sweat amount within a predetermined range, and adjusts the amount of sweat to evaporate.
  • the dynamic contact angle of the droplet during the period between the peaks of the current is calculated for each estimated value, and An evaluation function for evaluating the correctness of the estimated value based on related known physical quantities, the measured sweat amount, the estimated value, the period of the peak of the current, and the calculation result of the dynamic contact angle.
  • the electrical signal is a current that changes due to droplets intermittently generated in the internal space of the wearable sensor due to sweating of the wearer
  • the sweat amount calculation unit calculates the measured sweat amount of the wearer based on the period of the peak of the current
  • the electrolyte concentration calculation unit calculates the measured value of the electrolyte concentration in the wearer's sweat based on the peak value of the current. calculate.
  • the wearable sensor is a base having a through hole that serves as a flow path for sweat of the wearer and the internal space communicating with an end on the exit side of the through hole.
  • a first electrode disposed on the surface of the base material where the entrance side end of the through hole is open, and a first electrode arranged on the surface of the base material that is open at the entrance side end of the through hole, so as to come into contact with sweat flowing into the internal space from the exit side opening of the through hole.
  • a water-absorbing structure disposed on the outlet side surface of the base material; and a water-absorbing structure disposed on the surface of the water-absorbing structure facing the base material so as to face the outlet side opening of the through hole. 2 electrodes, and the electrical signal is a current flowing between the first electrode and the second electrode due to droplets intermittently generated in the internal space due to perspiration of the wearer.
  • the wearable sensor is a base having a through hole that serves as a flow path for sweat of the wearer and the internal space communicating with an end on the exit side of the through hole.
  • a water-absorbing structure disposed on the exit side surface of the base material so as to come into contact with the sweat flowing out from the exit side opening of the through hole into the internal space;
  • a light emitting element configured to emit light toward the sweat that has flowed into the internal space, and a light receiving element configured to receive light transmitted through the sweat or light reflected by the sweat,
  • the electrical signal is a current flowing through the light receiving element due to droplets intermittently generated in the internal space due to sweating of the wearer.
  • the sweat analysis method of the present invention includes a first step of detecting an electrical signal derived from the sweat amount and electrolyte concentration of sweat secreted from the wearer's skin using a wearable sensor; a second step of measuring the temperature of the internal space of the wearable sensor into which sweat of the wearer flows; a third step of measuring the relative humidity of the internal space of the wearable sensor into which sweat of the wearer flows; a fourth step of calculating a measured amount of sweat of the wearer based on the obtained electrical signal; and calculating a measured value of electrolyte concentration in the wearer's sweat based on the electrical signal obtained by the wearable sensor.
  • the method is characterized in that it includes a sixth step of calculating the true value of sweat amount and the true value of electrolyte concentration.
  • the present invention can be applied to technology for analyzing a person's sweat amount and electrolyte concentration in sweat.

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Abstract

Dispositif d'analyse de transpiration comprenant : un capteur portable (1) qui délivre un signal électrique dérivé d'une quantité de transpiration d'un porteur et une concentration en électrolyte ; un capteur de température (2) qui mesure la température d'un espace interne du capteur portable (1) dans lequel s'écoule la transpiration du porteur ; un capteur d'humidité (3) qui mesure l'humidité relative de l'espace interne ; et une section MCU (7). La section MCU (7) calcule une valeur de mesure de la quantité de transpiration et une valeur de mesure de la concentration en électrolyte dans la transpiration du porteur sur la base du signal électrique, et calcule une valeur réelle de la quantité de transpiration et une valeur réelle de la concentration en électrolyte qui sont corrigées pour les effets de réduction de la quantité de transpiration due à l'évaporation, sur la base d'une valeur physique connue concernant l'évaporation de la transpiration, la valeur de mesure de la quantité de transpiration, la valeur de mesure de la concentration en électrolyte, la température, et l'humidité relative.
PCT/JP2022/022267 2022-06-01 2022-06-01 Dispositif et procédé d'analyse de transpiration WO2023233568A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007252803A (ja) * 2006-03-24 2007-10-04 Konica Minolta Holdings Inc データ解析装置及びデータ解析方法
WO2021038742A1 (fr) * 2019-08-28 2021-03-04 日本電信電話株式会社 Capteur pouvant être porté, et dispositif et procédé d'analyse de transpiration

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007252803A (ja) * 2006-03-24 2007-10-04 Konica Minolta Holdings Inc データ解析装置及びデータ解析方法
WO2021038742A1 (fr) * 2019-08-28 2021-03-04 日本電信電話株式会社 Capteur pouvant être porté, et dispositif et procédé d'analyse de transpiration

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JESSICA FRANCIS, ISAAC STAMPER, JASON HEIKENFELD, ELIOT F. GOMEZ: "Digital nanoliter to milliliter flow rate sensor with in vivo demonstration for continuous sweat rate measurement", LAB ON A CHIP, ROYAL SOCIETY OF CHEMISTRY, UK, vol. 19, no. 1, 1 January 2019 (2019-01-01), UK , pages 178 - 185, XP055679527, ISSN: 1473-0197, DOI: 10.1039/C8LC00968F *

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