Biological signal measurement device and method for controlling biological

Abstract

A biological signal measurement device is provided with: a dry electrode; a member that fixes the electrode in a state in which the electrode is pressed against a living body; and a control main body for measuring a biological signal by means of the electrode, the control main body comprising: an impedance measurement unit for measuring the impedance between the electrode and the biological body; and a wearing state determination unit that determines whether or not the wearing state of the electrode is good on the basis of the value of the impedance at a point in time when the elapsed time from the time when the electrode is worn on the living body by the member reaches a predetermined time.

Description

TECHNICAL FIELD

[0001] The present application relates to a biological signal measuring apparatus that measures a biological signal by electrodes fixed to a skin surface. BACKGROUND

[0002] A technique is known in which electrodes are fixed to a skin surface of a living body and biological signals such as electrocardiogram and electromyogram are measured, and this technique is applied to various measuring apparatuses. In such an apparatus, if the contact state of the electrodes with the skin surface is not appropriate, the measurement accuracy can be degraded, or the measurement itself can not be performed.

[0003] In Patent Literature 1, the following idea is proposed: in an electromyogram measuring apparatus of the type in which an adhesive electrode is attached to a skin surface, whether or not the attachment state of each electrode is good is determined by measuring the electrical impedance value between two electrodes or the electrical resistance value between each electrode.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2007-195813 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The present inventors are promoting development of a measuring apparatus of the type in which a belt in which dry electrodes are embedded (hereinafter also referred to as "electrode belt") is wound around an arm or a leg to perform fixation of the electrodes to a skin surface. By adopting such a fixation structure of dry electrodes, the following advantages are obtained: since the patient himself / herself can easily perform wearing and removal of the apparatus, measurement can be easily performed, and since skin rash and the like do not occur, long-time measurement can be easily performed while keeping the state of wearing the apparatus unchanged. However, on the contrary, it is expected that if the patient himself / herself performs wearing and removal of the apparatus, the frequency of occurrence of poor wearing will increase. Therefore, from the viewpoint of improving the reliability and stability of measurement, it is desirable to have a mechanism that automatically determines the wearing state of the dry electrodes and reports to the patient in the case of poor wearing.

[0009] The present inventors, in the course of trial-manufacturing of the electrode belt and repeatedly performing wearing experiments, have learned that, among the causes of occurrence of poor wearing of the electrodes, there are two factors of the electrodes not being in proper contact with the skin surface (poor physical connection) and insufficient wetting between the electrodes and the skin surface. Furthermore, it has been found that, after a certain period of time has passed after the electrodes are worn, the case where insufficient wetting is eliminated by sweating occurs many times, and there are a certain number of patients in which the electrodes and the skin are not sufficiently wet even after a period of time has passed.

[0010] In the device of Patent Literature 1, since a wet electrode that is attached to the surface of the skin is used, wearing failure due to insufficient wetting is not taken into consideration. Therefore, in a case where the determination method of Patent Literature 1 is simply applied to a device of the dry electrode type, it is not possible to distinguish between insufficient wetting and physical connection failure, and a determination result of wearing failure is outputted in all cases. However, in a case where the cause is insufficient wetting, since there is a high possibility that it will be eliminated with the passage of time, it is not appropriate to immediately determine wearing failure. On the contrary, in a case of insufficient wetting, since it will not be eliminated even if the electrode is re-worn, a result that misleads the patient will be created.

[0011] The present application was accomplished in view of the above-described actual situations, and aims to provide a technology for appropriately making a determination of whether or not the wearing state of an electrode is good, and a report to a user, in a biological signal measurement device that employs a dry electrode.

[0012] Means for solving the technical problem

[0013] The present disclosure includes a biological signal measurement device that includes a dry electrode, a member that fixes the electrode in a state where the electrode is pressed against a living body, and a control main body that measures a biological signal through the electrode, the control main body having an impedance measurement section that measures an impedance between the electrode and the living body, and a wearing state determination section that determines whether or not the wearing state of the electrode is good, based on a value of the impedance from a time point at which the elapsed time of wearing the electrode to the living body by the member reaches a predetermined time.

[0014] It can also be that the predetermined time is set to a time of 5 minutes or more.

[0015] It can also be that the dry electrode includes a plurality of electrodes, and the wearing state determination section determines that the wearing state is not good in a case where the value of the impedance of at least any one of the plurality of electrodes is a predetermined threshold value or more at the time point at which the elapsed time reaches the predetermined time.

[0016] It can also be that the wearing state determination section determines that the wearing state is not good before the elapsed time reaches the predetermined time, in a case where the value of the impedance of the electrode or a temporal change conforms to a predetermined reference before the elapsed time reaches the predetermined time.

[0017] It can also be that the dry electrode includes a plurality of electrodes, and the predetermined reference is that the value of the impedance of all of the electrodes among the plurality of electrodes is a predetermined upper limit value or more.

[0018] It can also be that the dry electrode includes a plurality of electrodes, and the predetermined criterion is that a difference, a ratio, or a separation between a value of impedance of a part of the plurality of electrodes and a value of impedance of the other electrodes is equal to or greater than a predetermined value.

[0019] It can also be that the predetermined criterion is that an increase in a value occurs in a time change in impedance.

[0020] It can also be that the predetermined criterion is that a slope of a decrease in impedance is smaller than a predetermined slope.

[0021] It can also be that the biological signal measurement device further has a reporting section that reports to a user in a case where it is determined by the wearing state determination section that the wearing state is poor.

[0022] It can also be that the wearing state determination section determines a cause of the poor wearing state based on a value or a time change in impedance, and the reporting section makes the report to the user different depending on the cause of the poor wearing state.

[0023] It can also be that the control body has an operation section that is operated by a user after the electrode is worn, and the control body starts counting the elapsed time in a case where the operation section is operated by the user.

[0024] It can also be that the biological signal is an ECG (Electrocardiogram) signal.

[0025] It can also be that the member is a band provided with the electrode.

[0026] It can also be that the band is worn on an upper arm of the living body.

[0027] The present disclosure includes a control method of a biological signal measurement device that measures a biological signal by a dry electrode, the control method having: a step of counting an elapsed time from when the electrode is worn on a living body; a step of measuring impedance between the electrode and the living body; and a step of determining whether or not a wearing state of the electrode is good based on a value of the impedance at a point in time at which the elapsed time reaches a predetermined time.

[0028] The present application can be understood as a biological signal measurement device having at least a part of the above-described configuration, or as an electrocardiograph that measures an ECG signal as a biological signal. Alternatively, it can be understood as a wearing state determination device mountable on a biological signal measurement device. In addition, the present application can be understood as a wearing state determination method including at least a part of the above-described processing, a control method of a biological signal measurement device, or a program for realizing the method, a storage medium in which the program is non-transitorily stored. Note that the above-described configuration and processing can be combined with each other as much as possible to constitute the present application.

[0029] Effects of the Invention

[0030] According to the present application, in a biological signal measurement device that employs a dry electrode, determination of whether the wearing state of the electrode is good or not, and reporting to the user, can be appropriately performed. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a view showing a state in which a biological signal measurement device is worn on the upper arm.

[0032] Figure 2 is a plan view of a biological signal measurement device.

[0033] Figure 3 is a perspective view of a biological signal measurement device.

[0034] Figure 4 is a block diagram showing a functional configuration of a control main body.

[0035] Figure 5 is a flowchart showing a flow of a determination process of a wearing state in the first embodiment.

[0036] Figure 6 is a flowchart showing a flow of a determination process of a wearing state in the second embodiment.

[0037] Figure 7 is a view showing an example of a time change in an impedance value.

[0038] Figure 8 is a flowchart showing a flow of a determination process of a wearing state in the third embodiment.

[0039] Figure 9 is a view showing an example of a reference when determining a wearing state in the third embodiment. DETAILED DESCRIPTION

[0040] <APPLICATION EXAMPLE>

[0041] REFERENCE Figure 1 One of application examples of the present application will be described.

[0042] The living body signal measurement device 1 is a portable measurement device to be worn on a living body. The living body signal measurement device 1 has the belt 10 provided with one or more dry electrodes 11 and the control main body 12 that measures a living body signal through the electrodes 11, as main components.

[0043] The living body signal to be measured is also called a living body electric signal or a living body potential, and is an electric signal generated in conjunction with the activity of a living body. For example, there are an electrocardiogram (a minute electric signal in conjunction with a beat), an electromyogram (a minute electric signal in conjunction with the activity of a muscle), an electroencephalogram (a minute electric signal in conjunction with the activity of a brain), and the like. As a measurement site where the belt 10 is to be worn, the upper limbs (upper arms, forearms, wrists, hands, fingers), the lower limbs (thighs, shanks, ankles, feet, toes), the head, the neck, the chest, the abdomen, the ear, and the like can be exemplified, and can be appropriately selected in accordance with the kind of the living body signal to be measured, the measurement algorithm, and the like.

[0044] At the time of measurement, after the user himself or herself winds the belt 10 around the measurement site to wear the device 1, measurement is started by pressing a button or the like of the control main body 12. At this time, if there is a poor physical connection such as a poor tightening of the belt 10, a lifting of the electrodes 11 from the skin surface, or the like, correct measurement cannot be performed. Therefore, in such a case, the user needs to be reported, and to take a countermeasure such as re-wearing the belt 10. However, even if the physical connection of the electrodes 11 to the skin surface is good, there is a case where the electric connection between the electrodes 11 and the skin surface becomes poor due to a lack of wetness. Therefore, if only the goodness or badness of the electric connection between the electrodes 11 and the skin surface is evaluated, it cannot be distinguished whether the physical connection is poor or the wetness is insufficient, and the user cannot be guided to an appropriate countermeasure.

[0045] Therefore, the living body signal measurement device 1 determines whether the wearing state of the electrodes 11 is good or not, based on the contact impedance between the electrodes 11 and the skin surface at a time point at which the elapsed time from the wearing of the electrodes 11 reaches a predetermined time Tw. That is, the determination of whether the wearing state is good or not is not performed immediately after the wearing of the electrodes 11, but is intentionally performed after a lapse of the predetermined time Tw. Since the wetting of the electrodes 11 and the skin surface due to sweating is expected by providing such a waiting time, it is possible to determine whether the physical connection is poor (that is, whether re-wearing is necessary) with high accuracy.

[0046] The predetermined time (waiting time) Tw can be set to a time of 5 minutes or more and 30 minutes or less. This is because, if a time of this degree elapses in the state where the electrodes 11 are worn, a sufficient wet state (that is, a state where the electric connection of the electrodes 11 to the skin surface is maintained to a degree where the contact impedance can be measured and evaluated) is obtained in almost all users.

[0047] The following describes an embodiment of the present application with a specific configuration example in which the present application is applied to an upper arm electrocardiograph.

[0048] <First Embodiment>

[0049] (Device Configuration)

[0050] Reference Figures 1-3 An embodiment of the present application will be described. Figure 1 is a diagram showing a state in which the biological signal measuring device 1 is worn on the upper arm, Figure 2 is a plan view of the biological signal measuring device 1, Figure 3 is a perspective view of the biological signal measuring device 1.

[0051] The biological signal measuring device 1 of the present embodiment is an upper arm electrocardiograph worn on the upper arm of a user (preferably the left upper arm near the heart) and used for measuring an ECG (Electrocardiogram) signal (electrocardio signal) as a biological signal.

[0052] The biological signal measuring device 1 has a band 10, a plurality of electrodes 11 fixed to the band 10, and a control body 12 fixed to the band 10, as main components.

[0053] The band 10 is a member (fixing member) for fixing the electrodes 11 in a state in which the electrodes 11 are pressed against a living body. In the present embodiment, a band-shaped band 10 composed of a material having flexibility and softness (for example, chemical fiber, silicon, leather, or the like) is used. A fixing mechanism 13 is provided at the lengthwise end portion of the band 10. As shown in Figure 1 and Figure 3 By providing the band 10 in a loop shape and securing it with the fixing mechanism 13, the biological signal measuring device 1 can be worn on the upper arm, as shown in

[0054] The plurality of electrodes 11 (also referred to as an electrode array) are embedded and fixed to the band 10 in such a manner that their contact surfaces with the living body are exposed on the inner side (living body side) of the band 10. The plurality of electrodes 11 are arranged in a row at equal intervals in the lengthwise direction of the band 10. By this, when the band 10 is wound around the arm, the electrodes 11 come into contact with different positions around the arm. The number of electrodes 11 can be arbitrarily designed. If the purpose is to measure an ECG signal, it is sufficient to have at least two electrodes 11 (one electrode pair), and in order to improve the reliability and robustness of the measurement, three or more electrodes 11 can be provided. In the present embodiment, a configuration in which six electrodes 11 (three electrode pairs) are provided is adopted.

[0055] The electrode 11 is a dry-type metal electrode. A wet-type electrode (a gel electrode or the like) has a problem of a possibility of causing skin rashes, itching, low durability, low maintenance, and the like if worn for a long time, and in contrast, the dry-type electrode 11 does not have such a problem. With regard to the biological signal measurement device 1 of the present embodiment, since it is assumed that the ECG signal is continuously worn and monitored for 24 hours, the dry-type electrode 11 is preferable.

[0056] The control body 12 is a processing unit that performs control and signal processing of the biological signal measurement device 1. The control body 12 has, for example, a structure in which a processor, a memory, a battery, and other circuits are installed inside a housing made of resin or metal. A physical switch and a display can also be provided in the control body 12. Although not shown, the control body 12 is connected to the plurality of electrodes 11 through signal lines.

[0057] (CONTROL BODY)

[0058] Figure 4 is a block diagram showing an example of a functional configuration of the control body 12.

[0059] The control body 12 has a measurement electrode selection section 30, an ECG measurement section 20, an ECG signal processing section 21, an ECG heart beat information calculation section 22, an ECG signal quality determination section 23, an AF determination section 24, a storage section 25, a communication section 26, an operation section 27, as a configuration relating to measurement of an ECG signal. The measurement electrode selection section 30 selects a pair of electrodes for measurement of an ECG signal. The ECG measurement section 20 is a circuit that amplifies a potential difference between the selected pair of electrodes by a differential amplifier and outputs as an ECG signal. The ECG signal processing section 21 is a section that performs AD conversion and filter processing of an ECG signal, and has an AD conversion section 210 that AD-converts an ECG signal, an electromagnetic noise removal section 211 that removes electromagnetic noise from an ECG signal to improve SN ratio, and a baseline fluctuation removal section 212 that removes baseline fluctuation (fluctuation of low frequency) of an ECG signal. The ECG heart beat information calculation section 22 is a section that extracts various heart beat information from an ECG signal, and has an R wave detection section 220, an RRI calculation section 221, a heart beat fluctuation calculation section 222, a P wave detection section 223. The ECG signal quality determination section 23 is a section that determines whether or not the quality of an ECG signal is good (i.e., whether or not data with accuracy or reliability suitable for a purpose of diagnosis or the like can be measured). The AF determination section 24 is a section that detects occurrence of AF (Atrial Fibrillation) or calculates an index relating to AF, based on heart beat information. The storage section 25 is a nonvolatile memory that stores measured or calculated data. The communication section 26 is a section that performs data communication with an external device (e.g., a user's smartphone, another health device, a home server, or the like) through wireless. The operation section 27 is an input interface for a user to perform input operation. The operation section 27 can be either a physical button or a touch panel display.

[0060] In addition, the control body 12 has a measurement electrode selection section 30, an impedance measurement section 31, an impedance signal processing section 32, a wearing state determination section 33, a reporting section (notification section) 34, as a configuration relating to automatic determination of a wearing state of the electrodes 11. The measurement electrode selection section 30 selects a pair of electrodes for measurement of impedance. The impedance measurement section 31 is a circuit that measures contact impedance between the electrodes 11 and a skin surface by flowing a measurement current between the selected pair of electrodes. In the present embodiment, a sine wave AC of about 10 Hz close to an ECG signal is used as the measurement current. The impedance signal processing section 32 is a section that performs AD conversion or the like of a measured signal and solves an impedance value (kΩ). The wearing state determination section 33 is a section that determines whether or not the wearing state of the electrodes 11 is good, based on the measured impedance value. The reporting section 34 is a section that performs reporting to a user according to a determination result of the wearing state determination section 33.

[0061] (Determination processing of wearing state)

[0062] Figure 5 The flowchart for determining the wearing status in the first embodiment is shown.

[0063] After the user wraps the strap 10 around their upper arm and secures it with the fixing mechanism 13, and after the operation unit 27 instructs the user to start the measurement, the processor of the control unit 12 begins... Figure 5 The judgment and processing. It should be noted that although the measurement and processing of ECG signals are also related to... Figure 5 The determination and processing are performed in parallel, but since they are not directly related to the features of this invention, the details of the measurement processing are omitted in this specification.

[0064] After detecting that the user has instructed to start the measurement, the wearing status determination unit 33 of the control unit 12 considers that the user has worn the electrode 11 and begins counting the "elapsed time Tp since wearing the electrode 11" (step S100). It should be noted that, although the user operation is used as the trigger for counting the elapsed time Tp in this embodiment, it is also possible to use an optical / electrical / magnetic / physical sensor to detect that the strap 10 or electrode 11 is worn on the arm to start counting the elapsed time Tp.

[0065] In step S101, impedance measurement is performed. Specifically, the electrode selection unit 30 selects a pair of electrodes 11 for measurement, the impedance measurement unit 31 measures the contact impedance between the selected electrodes 11, the impedance signal processing unit 32 calculates the contact impedance value, and sets the electrode 11 number n, the elapsed time Tp, and the impedance value Zn as a set and saves them to the storage unit 25 (in the case of six electrodes 11, n = 1, 2, ..., 6). By performing this measurement process on each of the multiple electrodes 11, the impedance value of each electrode 11 is recorded in the storage unit 25.

[0066] In step S102, the wearing status determination unit 33 determines whether the elapsed time Tp of the measurement time in step S101 has reached the predetermined time Tw. If the elapsed time Tp has not reached the predetermined time Tw (Tp < Tw), the process returns to step S101. Through this control, impedance measurements are repeatedly performed at certain time intervals Ti until the elapsed time Tp reaches the predetermined time Tw. In this embodiment, for example, Tw is set to 10 minutes and Ti to 1 minute.

[0067] When the elapsed time Tp reaches the predetermined time Tw (Tp ≥ Tw), the wearing state determination section 33 determines whether or not the wearing state of the electrode 11 is good or not based on the impedance value Zn at that time point (step S103). Specifically, if the impedance value Zn of all the electrodes 11 is lower than a predetermined threshold value Zth, the wearing state determination section 33 determines "wearing state: good", and in the case where the impedance value Zn of at least any one of the electrodes 11 is Zth or more, the wearing state determination section 33 determines "wearing state: bad". In the present embodiment, for example, Zth = 100 kΩ is set.

[0068] In the case where the wearing state is determined to be bad (step S104), the reporting section 34 reports to the user and urges to rewrap the belt 10 (step S105). The method of the report is arbitrary. For example, it is conceivable to sound a warning sound, to output a voice message urging to rewrap the belt 10, to display a message on a display, to report by vibration, light, to transmit a message to an external device (a smartphone or the like held by the user), and the like.

[0069] In the determination processing of the present embodiment, the contact state of the electrode 11 to the skin surface is evaluated not based on the contact impedance immediately after the electrode 11 is worn, but based on the contact impedance after a predetermined time elapses. Since the measurement and evaluation of the impedance are performed after waiting until the wetness between the electrode 11 and the skin surface is sufficiently increased by sweating, it is possible to exclude the measurement failure due to insufficient wetness as much as possible, and thus it is possible to determine the physical connection failure of the electrode 11 such as lifting (that is, a state where the belt 10 needs to be rewrapped) with high accuracy.

[0070] <Second Embodiment>

[0071] Although it is considered that, as in the first embodiment, by providing the waiting time of the predetermined time Tw, the insufficient wetness can be eliminated in most cases, there can be a certain number of people in which the electrode 11 and the skin do not become sufficiently wet even if a sufficient time elapses. In addition, it can also depend on the environment of the site (temperature, humidity, and the like). If it is a case where the cause is insufficient wetness, the condition cannot be improved by rewrapping the belt 10, and it is necessary to apply cream, lotion, or wet the electrode to the skin for improving the wetness between the electrode 11 and the skin surface. Therefore, in the second embodiment, after it is determined that the wearing state is bad by the method of the first embodiment, it is discriminated whether the cause of the bad is insufficient wetness or physical connection failure.

[0072] Figure 6 The flow of the determination processing of the wearing state in the second embodiment is shown. The same step numbers are attached to the same parts as the determination processing of the first embodiment. Hereinafter, the processing different from the first embodiment is explained as the center.

[0073] In the case where the wearing state is determined to be poor (step S104), the wearing state determination section 33 infers, based on the impedance values Zn of the respective electrodes 11, whether the cause of the poor wearing is physical connection failure such as warping of the electrodes 11 or insufficient wetness between the electrodes 11 and the skin (step S200). Specifically, in the case where the impedance value Zn is equal to or greater than the threshold value Zth in all of the electrodes 11, the wearing state determination section 33 determines that the cause is insufficient wetness, and in other cases, determines that the cause is physical connection failure. Even if the wrapping method of the belt 10 is poor, it is difficult to imagine that physical connection failure occurs in all of the electrodes 11, and at least some of the electrodes 11 will be in close contact with the skin. Therefore, even if a predetermined time Tw elapses, there are no electrodes 11 whose impedance value Zn is less than the threshold value Zth, and it is reasonable to consider that the cause is insufficient wetness.

[0074] The reporting section 34 can make the report to the user different between the case where the wearing state is poor due to insufficient wetness between the electrodes 11 and the skin surface and the case where the wearing state is poor due to the electrodes 11 not being in proper contact with the skin surface. For example, in the case where it is determined in step S200 that the cause is insufficient wetness, the reporting section 34 urges the user to perform a countermeasure for improving wetness such as applying cream (step S201). On the other hand, in the case where it is determined in step S200 that the cause is physical connection failure, the reporting section 34 urges the user to rewrap the belt 10 (step S202).

[0075] According to the determination processing of the present embodiment, in addition to the same effects as the first embodiment, there is an advantage that in the case where insufficient wetness does not disappear due to the user's constitution, the environment, and the like, the user can be guided to an appropriate countermeasure, and a measurement device with excellent usability can be provided.

[0076] Note that the cause inference in step S200 can also be another method. Figure 7 Examples of the time variation of the impedance value Zn are shown in FIGS. 70 to 72. The horizontal axis is elapsed time Tp (minutes), and the vertical axis is the impedance value Zn (kΩ). The three graphs respectively show a normal case 70, a case where there is physical connection failure such as warping of the electrodes 11 71, and a case where insufficient wetness does not disappear 72. In the normal case 70, the impedance value Zn is equal to or greater than the threshold value Zth in all of the electrodes 11. In the case where there is physical connection failure such as warping of the electrodes 11 71, the impedance value Zn is equal to or greater than the threshold value Zth in at least some of the electrodes 11. In the case where insufficient wetness does not disappear 72, the impedance value Zn is less than the threshold value Zth in at least some of the electrodes 11. Figure 7It can be seen that under normal circumstances 70, even if the initial impedance value Zn is high due to insufficient moisture, the moisture will increase over time, and the impedance value Zn will gradually decrease, falling below the threshold Zth at the predetermined time Tw. However, in the case of poor physical connection 71, the contact state between the electrode 11 and the skin surface is unstable, so the impedance value Zn changes unstablely and irregularly, either rising or falling. In addition, in the case 72 where insufficient moisture is not eliminated, the following pattern is observed: because the electrode 11 is in contact with the skin surface, the impedance value Zn gradually decreases over time, but its slope is small, and the impedance value Zn does not fall below the threshold Zth for a long time. Therefore, for example, the wearing state determination unit 33 may observe the change of the impedance value Zn from the time the strap 10 is first worn until the predetermined time Tw, and if the impedance value Zn increases midway, it is determined that "the cause is poor physical connection", and if the impedance value Zn decreases monotonically, it is determined that "the cause is insufficient moisture".

[0077] <Third Implementation Method>

[0078] In the first and second embodiments, the wearing status of the electrode 11 is determined after a predetermined time Tw has elapsed. However, it is also possible to report to the user at the time point if it is clearly determined that the wearing is not good before the predetermined time Tw has elapsed.

[0079] Figure 8 The flow chart for determining the wearing state in the third embodiment is shown. The same step numbers are used for parts that are the same as in the first and second embodiments. The following description focuses on the processes that differ from the first and second embodiments.

[0080] After the impedance measurement is performed in step S101, in step S300, the wearing status determination unit 33 determines whether the wearing status of electrode 11 is good or bad based on the impedance value Zn from when electrode 11 was first worn until the current time point. To distinguish it from the determination process in step S103, the determination process in step S300 is called "early determination process." If a poor wearing condition is determined in the early determination process (step S301), a report is immediately issued and the process ends (step S302). In the early determination process, the impedance value Zn or its change over time is evaluated to see if it conforms to a predetermined benchmark. Figure 9 An example of a predetermined benchmark is shown in the figure.

[0081] (1) The reference 1 is that the impedance value Zn of all of the plurality of electrodes 11 is equal to or higher than a predetermined upper limit value Zu. The upper limit value Zu refers to a state in which the skin is extremely dry, and the degree is such that sufficient moisturizing cannot be obtained even if a predetermined time Tw elapses. In the present embodiment, for example, Zu = 900 kΩ is set. For example, in a case where the impedance value Zn of all of the electrodes 11 is equal to or higher than Zu in the first measurement of the electrodes 11 immediately after wearing, the wearing state determination section 33 immediately determines that the wearing is poor, and the reporting section 34 urges the user to apply cream or the like.

[0082] (2) The reference 2 is that the impedance value Zn of a part of the plurality of electrodes 11 is significantly higher than the impedance value Zn of the other electrodes 11. In a case where the winding method of the belt 10 is poor, the electrodes 11 in which physical connection is poor are one or two. Therefore, if the impedance values Zn of the plurality of electrodes 11 are compared, the impedance value Zn of only the part of the electrodes 11 in which connection is poor is significantly higher than the others. In a case where such a situation is observed, it can be immediately determined that the wearing is poor, and the user is urged to re-wind the belt 10. Note that how to determine whether the impedance value Zn of the part of the electrodes 11 is significant can be performed. For example, in a case where the difference between the maximum value Zmax of the impedance values Zn of the plurality of electrodes 11 and the average value Zave of the impedance values Zn other than the maximum value Zmax is equal to or higher than a predetermined value, it can be determined that it is "significant". Alternatively, in a case where the ratio of the maximum value Zmax to the average value Zave is equal to or higher than a predetermined value, it can also be determined that it is "significant". Alternatively, it can also be that the plurality of electrodes 11 is divided into a first group and a second group according to the magnitude of the impedance value Zn, and in a case where the difference or the ratio between the representative value (for example, the maximum value, the average value, or the like) of the impedance value Zn of the first group and the representative value (for example, the maximum value, the average value, or the like) of the impedance value Zn of the second group is equal to or higher than a predetermined value, it is determined that it is "significant". Alternatively, it can also be determined that it is "significant" in a case where the separation degree (inter-group variance or the like) between the first group and the second group is equal to or higher than a predetermined value.

[0083] (3) The reference 3 is that an increase in the value occurs in the time change of the impedance value Zn. As also described in the second embodiment, in a case where the electrodes 11 are in correct contact with the skin, the impedance value Zn monotonically decreases. Therefore, in a case where an increase in the impedance value Zn occurs in any of the plurality of electrodes 11, it is immediately determined that the wearing is poor because physical connection is poor in the electrode 11, and the user is urged to re-wind the belt 10.

[0084] (4) Reference 4 is that the slope of the decrease in the impedance value Zn is smaller than a predetermined slope. In the case where the electrode 11 is in proper contact with the skin, the impedance value Zn monotonously decreases. The decrease curve in this case can be simply approximated by a linear equation. Therefore, for example, the slope of the decrease curve can be approximately calculated at the stage where the impedance is measured for 3 to 4 points, and it can be predicted to what extent the impedance value Zn decreases after a predetermined time Tw elapses. Here, if the slope of the decrease curve is too small, the impedance value Zn cannot be expected to be lower than the threshold value Zth even if the predetermined time Tw elapses, in which case, it can be immediately determined that the wearing is poor, and the user can be urged to take measures such as applying a cream.

[0085] By combining the above-described determination processes, in the case where it is definitely determined that the wearing is poor, the user can be urged to take measures before the elapsed time Tp reaches the predetermined time Tw. For example, if it is reference 1 or 2, it can be determined even after the electrode 11 is just worn, if it is reference 3, it can be determined at the point of time where the impedance starts to increase, and if it is reference 4, it can be determined at the point of time where the measurement values that can predict the degree of the decrease curve of the impedance are accumulated. Therefore, according to the present embodiment, the convenience of the device can be further improved.

[0086] <Other>

[0087] The above-described embodiments are merely illustrative of the modes of the configuration of the present application. The present application is not limited to the above-described specific embodiments, and various modifications can be made within the scope of the technical idea thereof. For example, the body part where the device is worn can be a part other than the upper arm. In addition, as the fixing member for fixing the electrode 11 in a state where the electrode 11 is pressed against the living body, in addition to the band-shaped member that winds the electrode 11 around the measurement part of the living body in a state where the electrode 11 contacts the living body as in the above-described embodiments, a bag-shaped member that wraps in a state where the measurement part of the living body is covered, a ring-shaped member can be used. In addition, the fixing member can have stretchability or deformability in order to correspond to the size (diameter) of the measurement part of the living body. Alternatively, in the case where it is made of a material that has no stretchability, it can have a structure where the length is adjustable. The number of the electrodes 11 can be one or more. The arrangement of the plurality of electrodes 11 need not be in one row, and can be configured in a two-dimensional array. In addition, it can not be equidistant, but can have a deviation in the arrangement interval of the electrodes 11. The electrode 11 can be integrated with the fixing member (band 10), or can be a structure different from the fixing member. The control body 12 can not be fixed to the band 10. For example, the control body 12 and the band 10 can be different structures, and a cable can be used to connect between the control body 12 and the band 10 (electrode 11). The biological signal of the measurement target is not limited to the ECG signal, and can be, for example, an electromyogram signal, an electroencephalogram signal.

[0088] This specification includes the following disclosures.

[0089] [Postscript 1]

[0090] A biological signal measuring device (1) comprising:

[0091] Dry electrode (11);

[0092] A component (10) for fixing the electrode (11) while it is pressed against a living organism; and

[0093] The control unit (12) measures biological signals through the electrodes (11).

[0094] The control body (12) has:

[0095] Impedance measuring unit (31) measures the impedance between the electrode (11) and the organism; and

[0096] The wearing status determination unit (33) determines whether the wearing status of the electrode (11) is good or bad based on the impedance value at the time point from the time elapsed since the electrode (11) was worn on the organism by the component (10) to the time point when a predetermined time has elapsed.

[0097] [Postscript 2]

[0098] According to the biological signal measuring device (1) described in Appendix 1, wherein,

[0099] The predetermined time is set to be 5 minutes or more.

[0100] [Postscript 3]

[0101] According to the biological signal measuring device (1) described in Appendix 1 or Appendix 2, wherein,

[0102] The dry electrode includes multiple electrodes (11),

[0103] When the elapsed time reaches the predetermined time, if the impedance of at least any one of the plurality of electrodes (11) is above a predetermined threshold, the wearing status determination unit (33) determines that the wearing status is poor.

[0104] [Postscript 4]

[0105] The biological signal measuring device (1) according to any one of Appendix 1 to Appendix 3, wherein,

[0106] In a case where the value or the temporal change of the impedance of the electrode (11) before the elapsed time reaches the predetermined time conforms to a predetermined reference, the wearing state determination unit (33) determines that the wearing state is poor before the elapsed time reaches the predetermined time.

[0107] [Note 5]

[0108] The biological signal measurement device (1) according to Note 4, wherein

[0109] The dry electrode includes a plurality of electrodes (11),

[0110] The predetermined reference is that the value of the impedance of all of the electrodes (11) among the plurality of electrodes (11) is equal to or greater than a predetermined upper limit value.

[0111] [Note 6]

[0112] The biological signal measurement device (1) according to Note 4 or Note 5, wherein

[0113] The dry electrode includes a plurality of electrodes (11),

[0114] The predetermined reference is that the difference, the ratio, or the separation between the value of the impedance of a part of the electrodes (11) among the plurality of electrodes (11) and the value of the impedance of the other electrodes (11) is equal to or greater than a predetermined value.

[0115] [Note 7]

[0116] The biological signal measurement device (1) according to any one of Note 4 to Note 6, wherein the predetermined reference is that an increase in the value occurs in the temporal change of the impedance.

[0117] [Note 8]

[0118] The biological signal measurement device (1) according to any one of Note 4 to Note 7, wherein

[0119] The predetermined reference is that the slope of the decrease in the impedance is smaller than a predetermined slope.

[0120] [Note 9]

[0121] The biological signal measurement device (1) according to any one of Note 1 to Note 8, wherein

[0122] The biological signal measurement device (1) further has a reporting unit (34) that reports to a user in a case where it is determined by the wearing state determination unit that the wearing state is poor.

[0123] [Note 10]

[0124] The biological signal measuring apparatus (1) according to any one of the following Notes 9 to 22, wherein

[0125] The wearing state determination section (33) determines the cause of the poor wearing state based on the value or the temporal change of the impedance,

[0126] The reporting section (34) makes the report to the user different depending on the cause of the poor wearing state.

[0127] [Note 11]

[0128] The biological signal measuring apparatus (1) according to any one of the following Notes 1 to 10, wherein

[0129] The control body (12) has an operation section (27) which is operated by the user after the electrode (11) is worn,

[0130] The control body (12) starts counting the elapsed time when the operation section (27) is operated by the user.

[0131] [Note 12]

[0132] The biological signal measuring apparatus (1) according to any one of the following Notes 1 to 11, wherein

[0133] The biological signal is an ECG (Electrocardiogram) signal.

[0134] [Note 13]

[0135] The biological signal measuring apparatus (1) according to any one of the following Notes 1 to 12, wherein

[0136] The member is a band (10) provided with the electrode (11).

[0137] [Note 14]

[0138] The biological signal measuring apparatus (1) according to Note 13, wherein

[0139] The band (10) is worn on the upper arm of the living body.

[0140] [Note 15]

[0141] A control method of a biological signal measuring apparatus (1) which measures a biological signal by a dry electrode (11), the control method having the steps of:

[0142] counting an elapsed time from when the electrode (11) is worn on a living body;

[0143] measuring impedance between the electrode (11) and the living body; and

[0144] determining whether or not the wearing state of the electrode (11) is good based on the value of the impedance at the point in time at which the elapsed time reaches the predetermined time.

[0145] BRIEF DESCRIPTION OF DRAWINGS

[0146] 1: living body signal measurement device, 10: band, 11: electrode, 12: control main body, 13: fixing mechanism.

Claims

1. A biological signal measuring device, comprising: Dry electrode; A component for fixing the electrode while it is pressed against a living organism; and The control unit measures biological signals through the electrodes. The control body has: The impedance measurement unit measures the impedance between the electrode and the organism; and The wearing status determination unit determines whether the wearing status of the electrode is good or bad based on the impedance value at a time point from the time elapsed since the electrode was worn on the organism by the component to a predetermined time point.

2. The biological signal measuring device according to claim 1, wherein, The predetermined time is set to be 5 minutes or more.

3. The biological signal measuring device according to claim 1 or 2, wherein, The dry electrode includes multiple electrodes. When the elapsed time reaches the predetermined time, and the impedance value of at least one of the plurality of electrodes is above a predetermined threshold, the wearing status determination unit determines that the wearing status is poor.

4. The biological signal measuring device according to any one of claims 1 to 3, wherein, If the impedance value or time change of the electrode before the elapsed time reaches the predetermined time meets a predetermined reference, the wearing status determination unit determines that the wearing status is poor before the elapsed time reaches the predetermined time.

5. The biological signal measuring device according to claim 4, wherein, The dry electrode includes multiple electrodes. The predetermined reference is that the impedance value of all of the plurality of electrodes is above a predetermined upper limit value.

6. The biological signal measuring device according to claim 4 or 5, wherein, The dry electrode includes multiple electrodes. The predetermined reference is that the difference, ratio, or separation between the impedance values ​​of a portion of the electrodes and the impedance values ​​of other electrodes is greater than a predetermined value.

7. The biological signal measuring device according to any one of claims 4 to 6, wherein, The predetermined reference is the increase in value that occurs during the time-varying change of impedance.

8. The biological signal measuring device according to any one of claims 4 to 7, wherein, The predetermined reference is that the slope of the impedance drop is smaller than a predetermined slope.

9. The biological signal measuring device according to any one of claims 1 to 8, wherein, The biosignal measuring device also has a reporting unit, which reports to the user when the wearing status determination unit determines that the wearing status is malfunctioning.

10. The biological signal measuring device according to claim 9, wherein, The wearing status determination unit determines the cause of poor wearing status based on impedance value or time changes. The reporting department will provide different reports to the user based on the reason for the poor wearing condition.

11. The biological signal measuring device according to any one of claims 1 to 10, wherein, The control unit has an operating section, which the user operates after wearing the electrodes. When the user operates the operation unit, the control unit begins to count the elapsed time.

12. The biological signal measuring device according to any one of claims 1 to 11, wherein, The biological signal mentioned is an ECG (Electrocardiogram) signal.

13. The biological signal measuring device according to any one of claims 1 to 12, wherein, The component is a strip on which the electrodes are provided.

14. The biological signal measuring device according to claim 13, wherein, The band is worn on the upper arm of the organism.

15. A control method for a biological signal measuring device, wherein the biological signal measuring device measures biological signals via dry electrodes, the control method comprising the following steps: The elapsed time since the electrodes were worn on the organism was counted; Measuring the impedance between the electrode and the organism; and Based on the impedance value at the time point when the predetermined time has elapsed, it is determined whether the electrode is in good or bad condition.

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