Blood glucose level measurement device and blood glucose level measurement method

Abstract

This blood glucose level measurement device comprises: an acquisition unit that outputs light to a living body and detects the light transmitted through the living body, thereby acquiring waveform calculation data for calculating an oxygenated hemoglobin waveform and a deoxygenated hemoglobin waveform; a phase difference calculation unit that calculates a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and a blood glucose level calculation unit that calculates the blood glucose level of the living body on the basis of the temporal phase difference. The acquisition unit is configured to be capable of executing first sampling for acquiring the waveform calculation data at a first sampling rate and second sampling for acquiring the waveform calculation data at a second sampling rate higher than the first sampling rate.

Description

Blood glucose level measuring device and blood glucose level measuring method

[0001] The present disclosure relates to a blood glucose level measuring device and a blood glucose level measuring method.

[0002] A known technology for measuring blood glucose levels in a living organism is, for example, the blood glucose measuring device described in Patent Document 1. The blood glucose measuring device described in Patent Document 1 calculates a temporal phase difference between an oxygenated hemoglobin waveform relating to the oxygenated hemoglobin concentration in the living organism's blood and a deoxygenated hemoglobin waveform relating to the deoxygenated hemoglobin concentration in the living organism's blood based on the detection results of light transmitted through the living organism, and calculates the blood glucose level of the living organism based on the temporal phase difference. This technology makes it possible to measure the blood glucose level of a living organism noninvasively and accurately.

[0003] Japanese Patent Publication No. 2018-57511, Japanese Patent No. 6846152, Japanese Patent No. 7263486, U.S. Patent No. 11122996, Japanese Patent No. 6482412, Japanese Patent No. 6510913, Japanese Patent No. 6636784, Japanese Patent No. 5997865, U.S. Patent No. 11154206, U.S. Patent No. 10772513, U.S. Patent No. 11089965

[0004] The above-described technology can improve the accuracy of blood glucose measurement by increasing the sampling rate at which data for calculating the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform is acquired, thereby more accurately calculating the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform. However, increasing the sampling rate increases the number of times that the blood glucose measuring device outputs light to the living body, which increases the battery consumption required to operate the blood glucose measuring device. In this case, there is a risk that the blood glucose measuring device will not be able to measure blood glucose levels continuously for the desired period of time.

[0005] The present disclosure aims to provide a blood glucose level measuring device and a blood glucose level measuring method that can measure blood glucose levels with high measurement accuracy and can improve the operating time of the blood glucose level measuring device.

[0006] A blood glucose measuring device according to one aspect of the present disclosure is [1] "a blood glucose measuring device comprising: an acquisition unit that acquires waveform calculation data for calculating an oxygenated hemoglobin waveform relating to an oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to a deoxygenated hemoglobin concentration in the blood of the living body by outputting light to the living body and detecting the light that has passed through the living body; a phase difference calculation unit that calculates a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and a blood glucose calculation unit that calculates a blood glucose level of the living body based on the temporal phase difference, wherein the acquisition unit is configured to perform first sampling to acquire the waveform calculation data at a first sampling rate and second sampling to acquire the waveform calculation data at a second sampling rate that is higher than the first sampling rate."

[0007] In the blood glucose measuring device, the acquisition unit is configured to perform first sampling, which acquires waveform calculation data at a first sampling rate, and second sampling, which acquires waveform calculation data at a second sampling rate higher than the first sampling rate. As a result, for example, at times when high blood glucose measurement accuracy is required, the acquisition unit performs second sampling, allowing blood glucose levels to be measured with high measurement accuracy. On the other hand, for example, at times when high blood glucose measurement accuracy is not required, the acquisition unit performs first sampling, reducing the amount of power consumed to acquire waveform calculation data (e.g., power for optical output) and improving the operating time of the blood glucose measuring device. Therefore, the blood glucose measuring device can measure blood glucose levels with high measurement accuracy and improve the operating time of the blood glucose measuring device.

[0008] The blood glucose measuring device according to one aspect of the present disclosure may be [2] "the blood glucose measuring device according to the above [1], wherein the first sampling rate is 20 Hz or more and 60 Hz or less." In this case, it is possible to calculate an approximate blood glucose level even when the first sampling is performed, and it is possible to further improve the operating time of the blood glucose measuring device.

[0009] The blood glucose measuring device according to one aspect of the present disclosure may be [3] "the blood glucose measuring device according to [1] or [2] above, wherein the second sampling rate is 100 Hz or more and 300 Hz or less." In this case, the blood glucose level can be measured with higher measurement accuracy when the second sampling is performed.

[0010] A blood glucose measuring device according to one aspect of the present disclosure may be [4] "the blood glucose measuring device according to any one of [1] to [3] above, wherein the acquisition unit is further configured to perform third sampling, which acquires the waveform calculation data at a third sampling rate that is higher than the first sampling rate and lower than the second sampling rate." In this case, when the third sampling is performed, the blood glucose level can be measured with higher measurement accuracy than when the first sampling is performed, and the operating time of the blood glucose measuring device can be improved compared to when the second sampling is performed. A variety of sampling methods suitable for various situations can be provided to users of the blood glucose measuring device.

[0011] The blood glucose measuring device according to one aspect of the present disclosure may be [5] "the blood glucose measuring device according to the above [4], wherein the third sampling rate is 50 Hz or more and 120 Hz or less." In this case, when the third sampling is performed, blood glucose levels can be measured with a relatively high degree of accuracy, and power consumption of the blood glucose measuring device can be reduced.

[0012] The blood glucose level measuring device according to one aspect of the present disclosure may be [6] "the blood glucose level measuring device according to any one of [1] to [5] above, wherein the phase difference calculating unit calculates a plurality of temporal phase differences, each of which is the temporal phase difference, and the blood glucose level calculating unit calculates an average temporal phase difference by performing an averaging process on the plurality of temporal phase differences, and calculates the blood glucose level based on the average temporal phase difference." In this case, noise contained in the calculated temporal phase difference can be reduced, and the blood glucose level can be calculated based on a more reliable temporal phase difference (average temporal phase difference).

[0013] The blood glucose measuring device according to one aspect of the present disclosure may be [7] "the blood glucose measuring device according to any one of [1] to [6] above, wherein the acquisition unit further acquires data related to the heart rate of the living body and determines whether to perform the second sampling based on the data related to the heart rate." In this case, the second sampling, which can measure the blood glucose level with higher measurement accuracy than the first sampling, can be performed at an appropriate timing based on the data related to the heart rate.

[0014] The blood glucose measuring device according to one aspect of the present disclosure may be [8] "the blood glucose measuring device according to any one of [1] to [7] above, further including an alertness detection unit that detects the alertness of the living body, and the acquisition unit determines whether to perform the second sampling based on the alertness." In this case, the second sampling, which can measure blood glucose levels with higher measurement accuracy than the first sampling, can be performed at an appropriate timing based on the alertness of the living body.

[0015] A blood glucose measuring device according to one aspect of the present disclosure may be [9] "the blood glucose measuring device according to any one of the above [1] to [8], further comprising a receiving unit that receives intake start information indicating that the living body has started to take a meal, and the acquisition unit performs the second sampling in response to the receiving unit's receipt of the intake start information." In this case, the second sampling, which can measure blood glucose levels with higher measurement accuracy than the first sampling, can be performed when the living body is eating, a time when blood glucose levels are likely to change.

[0016] A blood glucose measuring device according to one aspect of the present disclosure may be

[10] "the blood glucose measuring device according to any one of the above [1] to [9], further comprising a receiving unit that receives exercise start information indicating that the living body has started exercising, and the acquisition unit performs the second sampling in response to the receiving unit's receipt of the exercise start information." In this case, the second sampling, which can measure blood glucose levels with higher measurement accuracy than the first sampling, can be performed when the living body is exercising, a time when blood glucose levels are likely to change.

[0017] A blood glucose measuring device according to one aspect of the present disclosure is

[11] "a blood glucose measuring device comprising: an acquisition unit that acquires waveform calculation data for calculating an oxygenated hemoglobin waveform relating to an oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to a deoxygenated hemoglobin concentration in the blood of the living body by outputting light to the living body and detecting the light that has passed through the living body; a phase difference calculation unit that calculates a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and a blood glucose calculation unit that calculates a blood glucose level of the living body based on the temporal phase difference, wherein the acquisition unit is configured to be able to execute a first mode in which sampling is repeatedly performed at a first frequency to acquire the waveform calculation data at a sampling rate of 50 Hz or more, and a second mode in which the sampling is repeatedly performed at a second frequency that is higher than the first frequency."

[0018] In the blood glucose measuring device, the acquisition unit is configured to be able to execute a first mode in which sampling of waveform calculation data is repeatedly performed at a first frequency, that is, at a sampling rate of 50 Hz or higher, and a second mode in which the sampling is repeatedly performed at a second frequency higher than the first frequency. As a result, for example, when high-accuracy blood glucose level measurements are required frequently, the acquisition unit executes the second mode, allowing blood glucose levels to be measured frequently with high accuracy. On the other hand, when high-accuracy measurements are not required frequently, the acquisition unit executes the first mode, reducing the amount of power consumed to acquire waveform calculation data (e.g., power for optical output) and improving the operating time of the blood glucose measuring device. Therefore, the blood glucose measuring device can measure blood glucose levels with high accuracy and improve the operating time of the blood glucose measuring device.

[0019] The blood glucose measuring device according to one aspect of the present disclosure may be

[12] "the blood glucose measuring device according to the above

[11] , in which the first frequency is a frequency at which the sampling is performed at intervals of 5 minutes or more." In this case, the operating time of the blood glucose measuring device can be further improved.

[0020] The blood glucose measuring device according to one aspect of the present disclosure may be

[13] "the blood glucose measuring device according to

[11] or

[12] above, wherein the second frequency is a frequency at which the sampling is performed at intervals of 3 minutes or less." In this case, the blood glucose level can be calculated appropriately at a timing when blood glucose measurement with high measurement accuracy is required frequently.

[0021] The blood glucose measuring device according to one aspect of the present disclosure may be

[14] "the blood glucose measuring device according to any one of

[11] to

[13] above, wherein the acquisition unit acquires data related to the heartbeat of the living body and determines whether to execute the second mode based on the data related to the heartbeat." In this case, the second mode, in which waveform calculation data is sampled at a sampling rate of 50 Hz or more more frequently than in the first mode, can be executed at an appropriate timing based on the data related to the heartbeat.

[0022] The blood glucose measuring device according to one aspect of the present disclosure may be

[15] "the blood glucose measuring device according to any one of

[11] to

[14] above, further including an alertness detection unit that calculates the alertness of the living body, and the acquisition unit determines whether to execute the second mode based on the alertness." In this case, the second mode, in which waveform calculation data is sampled at a sampling rate of 50 Hz or more more frequently than in the first mode, can be executed at an appropriate timing based on the alertness of the living body.

[0023] The blood glucose level measuring device according to one aspect of the present disclosure may be

[16] "the blood glucose level measuring device according to any one of [1] to

[15] above, further comprising an information output unit that outputs information related to the blood glucose level." In this case, the information related to the blood glucose level can be notified to a living body or the like.

[0024] The blood glucose measuring device according to one aspect of the present disclosure may be

[17] "the blood glucose measuring device according to the above

[16] , wherein the information output unit outputs information related to the blood glucose level when the amount of fluctuation in the blood glucose level exceeds a predetermined value." In this case, for example, it is possible to notify the living body that the amount of fluctuation in the blood glucose level has exceeded a predetermined value, and that the risk or seriousness of the living body's health condition is increasing.

[0025] The blood glucose measuring device according to one aspect of the present disclosure may be

[18] "the blood glucose measuring device according to the above

[16] or

[17] , further comprising a blood pressure calculation unit that calculates a blood pressure value of the living body, and the information output unit outputs information related to the blood pressure value." In this case, the blood pressure value information can be notified to the living body, etc.

[0026] The blood glucose measuring device according to one aspect of the present disclosure may be

[19] "the blood glucose measuring device according to any one of the above

[16] to

[18] , wherein the blood glucose calculation unit calculates a blood glucose fluctuation rate when the living body takes in a meal, and the information output unit outputs information about the fluctuation rate as information about the blood glucose level." In this case, the living body can be notified of the blood glucose fluctuation rate when the living body takes in a meal.

[0027] A blood glucose level measurement method according to one aspect of the present disclosure is

[20] "a blood glucose level measurement method including the steps of: acquiring waveform calculation data for calculating an oxygenated hemoglobin waveform relating to an oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to a deoxygenated hemoglobin concentration in the blood of the living body by outputting light to the living body and detecting the light that has passed through the living body; calculating a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and calculating a blood glucose level of the living body based on the temporal phase difference, wherein the acquiring step includes first sampling to acquire the waveform calculation data at a first sampling rate or second sampling to acquire the waveform calculation data at a second sampling rate higher than the first sampling rate." For the reasons described above, this blood glucose level measurement method enables blood glucose levels to be measured with high measurement accuracy and can improve the operating time of a blood glucose measurement device.

[0028] A blood glucose level measurement method according to one aspect of the present disclosure is

[21] "a blood glucose level measurement method including the steps of: acquiring waveform calculation data for calculating an oxygenated hemoglobin waveform relating to an oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to a deoxygenated hemoglobin concentration in the blood of the living body by outputting light to the living body and detecting the light that has passed through the living body; calculating a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and calculating a blood glucose level of the living body based on the temporal phase difference, wherein the acquiring step executes a first mode in which sampling of the waveform calculation data is repeatedly performed at a first frequency, in which the waveform calculation data is acquired at a sampling rate of 50 Hz or more; or a second mode in which the sampling is repeatedly performed at a second frequency higher than the first frequency." For the reasons described above, this blood glucose level measurement method enables blood glucose levels to be measured with high measurement accuracy and can improve the operating time of a blood glucose measurement device.

[0029] According to the present disclosure, it is possible to provide a blood glucose level measuring device and a blood glucose level measuring method that can measure blood glucose levels with high measurement accuracy and improve the operating time of the blood glucose level measuring device.

[0030] Fig. 1 is a cross-sectional view of a blood glucose level measuring device and a living body according to one embodiment. Fig. 2 is a block diagram of the blood glucose level measuring device shown in Fig. 1. Fig. 3 shows the detection results of the light detecting unit shown in Fig. 1. Fig. 4 shows an oxygenated hemoglobin waveform and a deoxygenated hemoglobin waveform calculated based on the detection results shown in Fig. 3. Fig. 5 is a schematic diagram of the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform shown in Fig. 4. Fig. 6 is a flowchart showing each step of a blood glucose level measuring method according to a first embodiment. Fig. 7 is a flowchart showing each step of a blood glucose level measuring method according to a second embodiment.

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [First embodiment] [Configuration of blood glucose level measuring device]

[0032] Fig. 1 is a cross-sectional view of a blood glucose level measuring device and a living body according to this embodiment. Fig. 2 is a block diagram of the blood glucose level measuring device. Fig. 1 is a conceptual diagram for explaining the function of the blood glucose level measuring device 1, and does not necessarily show an actual cross-section of the blood glucose level measuring device 1.

[0033] The blood glucose level measuring device 1 shown in FIG. 1 is, for example, a wearable device, a smartphone, or a pulse oximeter. Examples of wearable devices include a smart watch and a smart ring. The smart watch or smart ring may be a smart watch or smart ring equipped with a pulse oximeter. In this embodiment, the blood glucose level measuring device 1 is a smart watch that has a function of measuring the blood glucose level of a living body 9. The living body 9 has a superficial tissue 91 and an internal tissue 92 that is located deeper inside the living body 9 than the superficial tissue 91. The surface 91a of the superficial tissue 91 is the surface of the skin of the living body 9. The living body 9 is, for example, a human body.

[0034] The blood glucose measuring device 1 measures the blood glucose level of a living organism 9. The blood glucose measuring device 1 includes a main body 2, a light output unit 3, a light detection unit 4, a body motion detection sensor 5, and an ECU (Electronic Control Unit) 6. The main body 2 has a front face 2a and a back face 2b facing the opposite side to the front face 2a. The front face 2a functions as a display screen that displays various information about the blood glucose measuring device 1. The blood glucose measuring device 1 is worn on the living organism 9 so that the back face 2b comes into contact with the skin of the living organism 9.

[0035] The light output unit 3 is provided in the main body 2. The light output surface of the light output unit 3 is exposed from the back surface 2b of the main body 2. The light output unit 3 has a light source that outputs light L (measurement light) to the living body 9. The light source is, for example, a light-emitting diode (LED), a laser diode (LD), or a superluminescent diode (SLD). The light L is emitted from the back surface 2b. The light L emitted from the light output unit 3 passes through the inside of the living body 9 and is then emitted again from the living body 9. The light output unit 3 is controlled by the ECU 6. Power for outputting the light L from the light output unit 3 may be supplied, for example, from a battery mounted in the blood glucose measuring device 1.

[0036] The wavelength range of the light L is, for example, from the red wavelength region of visible light to the near-infrared region (670 nm to 2500 nm). That is, the light output unit 3 outputs light L included in the range from the red wavelength region of visible light to the near-infrared region. The light output unit 3 outputs, for example, multiple lights L having different wavelengths. The light output unit 3 has multiple light sources. In this embodiment, the light output unit 3 has a first light source, a second light source, and a third light source. The first light source outputs a first measurement light L1 having a first wavelength, the second light source outputs a second measurement light L2 having a second wavelength, and the third light source outputs a third measurement light L3 having a third wavelength.

[0037] The second wavelength of the second measurement light L2 is longer than the first wavelength of the first measurement light L1. The third wavelength of the third measurement light L3 is longer than the first wavelength and shorter than the second wavelength. In this embodiment, the first wavelength is, for example, about 735 nm, the second wavelength is, for example, about 850 nm, and the third wavelength is, for example, about 810 nm. Note that the light output unit 3 may have a single light source that outputs probe light (e.g., white light) containing different wavelength components (the above-mentioned first wavelength, second wavelength, and third wavelength).

[0038] The light detection unit 4 is provided in the main body 2. The light detection unit 4 is separated from the light output unit 3. The light detection surface of the light detection unit 4 is exposed from the rear surface 2b of the main body 2. The light detection unit 4 has a light detection element that detects light L (transmitted light) output from the light output unit 3 and transmitted through the living body 9. The light detection element is, for example, a photodiode (PD). The light detection unit 4 also has a preamplifier that amplifies the photocurrent output from the light detection element and an A / D conversion circuit that converts the signal amplified by the preamplifier into a digital signal. The light detection unit 4 may have a CCD image sensor or a CMOS image sensor. The light detection unit 4 detects the first measurement light L1, the second measurement light L2, and the third measurement light L3 that have transmitted through the living body 9. The light detection unit 4 transmits a signal related to the intensity of the light L to the ECU 6.

[0039] When the light output unit 3 (first to third light sources) and the light detection unit 4 are mounted on a general pulse oximeter, the first to third light sources are not turned on simultaneously but are turned on sequentially, causing a time difference between the detection timings of the first to third measurement light L1 to L3 in the light detection unit 4. On the other hand, when the light detection unit 4 is configured using a multi-channel spectrometer or an RGB-CMOS sensor, the first to third light sources can be turned on simultaneously and the light L from each light source can be detected simultaneously, thereby reducing the time difference between the detection timings of the first to third measurement light L1 to L3.

[0040] The light detection unit 4 detects light L of at least two wavelengths and detects changes in the intensity of the light L over time. In this example, as shown in FIG. 3 , the light detection unit 4 detects at least first data D1 and second data D2. The first data D1 is, for example, a change in the intensity of the first measurement light L1 that has passed through the living body 9 and entered the light detection unit 4 over time. The second data D2 is, for example, a change in the intensity of the second measurement light L2 that has passed through the living body 9 and entered the light detection unit 4 over time. Each of the first data D1 and the second data D2 periodically fluctuates over time. Note that the respective periods of the first data D1 and the second data D2 approximately coincide with the cardiac cycle of the living body 9.

[0041] The body motion detection sensor 5 is a sensor that detects body motion of the living body 9. The body motion detection sensor 5 may be, for example, an acceleration sensor, a gyro sensor, or a geomagnetic sensor. The body motion detection sensor 5 may be configured by combining two or more sensors selected from the acceleration sensor, the gyro sensor, and the geomagnetic sensor.

[0042] The ECU 6 is provided in the main body 2. The ECU 6 is an electronic control unit having a central processing unit (CPU) and a storage unit such as a read-only memory (ROM) or a random access memory (RAM). In the ECU 6, for example, a program stored in the storage unit is executed by the CPU. The ECU 6 calculates the blood glucose level, pulse rate, heart rate, oxygen saturation concentration, and the like of the living body 9 based on a signal (detection result of the light detection unit 4) transmitted from the light detection unit 4. As shown in FIG. 2 , the ECU 6 includes a reception unit 61, an acquisition unit 62, a phase difference calculation unit 63, a blood glucose level calculation unit 64, a blood pressure calculation unit 65, a wakefulness detection unit 66, a blood glucose level prediction unit 67, and an information output unit 68. The ECU 6 may be configured as a single electronic unit or may be configured as multiple electronic units capable of communicating with each other.

[0043] The reception unit 61 receives various types of data or information. The reception unit 61 may receive data or information from another device connected to the blood glucose measuring device 1, or may receive data or information directly input to the blood glucose measuring device 1. For example, the data or information may be input by the living body 9 via a user interface of another device or the blood glucose measuring device 1. The other device connected to the blood glucose measuring device 1 may be, for example, a terminal (user terminal) used by a user (living body 9) of the blood glucose measuring device 1, or a database on a network (e.g., cloud).

[0044] As an example, the receiving unit 61 may receive intake start information indicating that the living body has started eating a meal and intake end information indicating that the living body has finished eating a meal. The receiving unit 61 may also receive information such as the contents of the meal (food items, amount, etc.) or approximate calories of the meal ingested by the living body. For example, when the living body 9 selects a food from a list of foods (e.g., a drop-down list) selectably displayed on the display of the user terminal, information such as the name or calories of the selected food may be transmitted from the user terminal to the receiving unit 61. The receiving unit 61 may also receive information such as the contents of the meal or approximate calories identified by image analysis of an image showing the meal or by reading a contactless communication tag attached to the food. In this case, the image analysis and tag reading may be performed by the user terminal or the blood glucose measuring device 1, or may be performed by a server connected to the blood glucose measuring device 1.

[0045] As another example, the receiving unit 61 may receive exercise start information indicating that the living body 9 has started exercising and exercise end information indicating that the living body has ended exercising. For example, when an operation to start an exercise mode (such as a running mode) in an exercise-related application executed by the operating system (OS) of the blood glucose measuring device 1 is performed via the user interface of the blood glucose measuring device 1, the receiving unit 61 may receive information indicating that the start operation has been performed as exercise start information. Also, when an operation to end the exercise mode in the same application is performed via the user interface of the blood glucose measuring device 1, the receiving unit 61 may receive information indicating that the end operation has been performed as exercise end information.

[0046] As another example, the receiving unit 61 may receive bathing start information indicating that the living body 9 has started bathing and bathing end information indicating that the living body 9 has finished bathing. For example, the receiving unit 61 may receive bathing start information and bathing end information input by the living body 9 via a user interface of the blood glucose measuring device 1 or a user terminal.

[0047] The receiving unit 61 may receive (acquire) information (biological information) about the living body 9 from an external database or a user terminal connected to the blood glucose level measuring device 1. The biological information may be information about the age, sex, height, weight, wake-up time, sleep onset time, sleep time (duration of sleep), meal times (time to start eating, duration of meal, etc.), exercise habits, etc. of the living body 9.

[0048] The acquisition unit 62 acquires oxygenated hemoglobin (O ２ The acquiring unit 62 acquires data (waveform calculation data) for calculating an oxygenated hemoglobin waveform related to the concentration of oxygenated hemoglobin (HHb) in the blood of the living body 9 and a deoxygenated hemoglobin waveform related to the concentration of deoxygenated hemoglobin (HHb) in the blood of the living body 9. In this example, the acquiring unit 62 acquires, as the waveform calculation data, first data D1 which is a change over time in the intensity of the first measuring light L1 and second data D2 which is a change over time in the intensity of the second measuring light L2 shown in FIG. 3 . The acquiring unit 62 controls the light output unit 3 and the light detection unit 4 to output light L to the living body 9 and detect the light L transmitted through the living body 9, thereby acquiring the waveform calculation data. The acquiring unit 62 acquires the waveform calculation data at a predetermined sampling rate. The acquisition process of the waveform calculation data by the acquiring unit 62 and the sampling rate will be described in detail later.

[0049] The phase difference calculation unit 63 calculates the phase difference as shown in FIG. 4 based on the waveform calculation data acquired by the acquisition unit 62. ２ An oxygenated hemoglobin waveform P1 relating to the Hb concentration and a deoxygenated hemoglobin waveform P2 relating to the HHb concentration are calculated. ２ The first data D1 and the second data D2 are data relating to the Hb concentration, and the deoxygenated hemoglobin waveform P2 is data relating to the HHb concentration of the blood of the living body 9. The phase difference calculation unit 63 calculates the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 by performing spectroscopic calculation processing based on, for example, the Modified Beer-Lambert (MBL) method on the waveform calculation data (the first data D1 and the second data D2 in this example).

[0050] Specifically, the phase difference calculation unit 63 calculates the difference between the intensity of the first data D1 at the first time and the intensity of the first data D1 at the second time (the amount of change over time in the intensity of the first data D1), the difference between the intensity of the second data D2 at the first time and the intensity of the second data D2 at the second time (the amount of change over time in the intensity of the second data D2), and the O ２ The extinction coefficients of Hb and HHb, and the O ２ Based on the respective absorption coefficients of Hb and HHb, the relative change in oxygenated hemoglobin over time (ΔO ２ The phase difference calculation unit 63 calculates the relative change in ΔO ２ Hb and ΔHHb are continuously calculated at predetermined time intervals (for example, about 16 milliseconds). ２ The change in Hb over time is the oxygenated hemoglobin waveform P1 shown in Fig. 4, and the change in ΔHHb over time is the deoxygenated hemoglobin waveform P2 shown in Fig. 4. The concentration index on the vertical axis in Fig. 4 is, for example, a volume concentration index (concentration x optical path length).

[0051] The phase difference calculation unit 63 calculates the temporal phase difference (hereinafter simply referred to as "temporal phase difference") between the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2. FIG. 5 is a schematic diagram of the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 shown in FIG. 4. The phase difference calculation unit 63 calculates the time difference between the first characteristic point C1 of the oxygenated hemoglobin waveform P1 and the second characteristic point C2 of the deoxygenated hemoglobin waveform P2 as the temporal phase difference Δθ. In this embodiment, the first characteristic point C1 is the bottom point of the oxygenated hemoglobin waveform P1, and the second characteristic point C2 is the bottom point of the deoxygenated hemoglobin waveform P2. The first characteristic point C1 may be, for example, a peak point or a notch point of the oxygenated hemoglobin waveform P1. The second characteristic point C2 may be, for example, a peak point or a notch point of the deoxygenated hemoglobin waveform P2.

[0052] The blood glucose level calculation unit 64 calculates the blood glucose level of the living body 9 based on the temporal phase difference Δθ calculated by the phase difference calculation unit 63. The blood glucose level calculation unit 64 calculates the blood glucose level of the living body 9 using the formula G = α × Δθ - β, where G is the blood glucose level of the living body 9, Δθ is the temporal phase difference, and α and β are coefficients determined according to the glucose metabolic capacity and the measurement site of the living body 9. The method of calculating the temporal phase difference Δθ and the blood glucose level is not limited, and may be, for example, the methods disclosed in Japanese Patent No. 6846152, Japanese Patent No. 7263486, or U.S. Patent No. 11122996.

[0053] The blood glucose level calculation unit 64 may calculate an average temporal phase difference ΔθA by performing an averaging process on the multiple temporal phase differences Δθ calculated by the phase difference calculation unit 63, and may calculate the blood glucose level based on the average temporal phase difference ΔθA. That is, in the above-mentioned formula G=α×Δθ−β, ΔθA may be used instead of Δθ. As an example, when the actual sampling rate of the waveform calculation data by the acquisition unit 62 is A, １ Hz, the sampling rate for the calculated blood glucose level is A ２ Hz (A ２ >A １ When it is desired to ensure the same level of reliability as in the case of (A ２ / A １ ) ２ The average value (arithmetic mean value) of the number of temporal phase differences Δθ may be calculated as the average temporal phase difference ΔθA. Specifically, when the sampling rate of the waveform calculation data obtained by the acquisition unit 62 is 25 Hz, and it is desired to ensure the same reliability as when the sampling rate is 250 Hz, the blood glucose level calculation unit 64 calculates the average temporal phase difference ΔθA by (250 Hz / 25 Hz). ２Alternatively, the average value of 100 temporal phase differences Δθ may be calculated as the average temporal phase difference ΔθA. When the blood glucose level calculation unit 64 calculates the arithmetic mean of multiple temporal phase differences Δθ as the average temporal phase difference ΔθA, the blood glucose level calculation unit 64 may identify abnormal values ​​of the temporal phase difference Δθ based on the detection data of the body motion detection sensor 5 and calculate the average temporal phase difference ΔθA by excluding the abnormal values. The abnormal value of the temporal phase difference Δθ to be excluded may be, for example, a temporal phase difference Δθ corresponding to a timing at which an abnormal body motion such as a sneeze occurred (such as a temporal phase difference Δθ that differs by a predetermined value or more from other temporal phase differences Δθ acquired at timings before and after the sneeze).

[0054] As another example, the blood glucose level calculation unit 64 may create a histogram of multiple temporal phase differences Δθ and calculate the mode in the histogram as the average temporal phase difference ΔθA. As another example, the blood glucose level calculation unit 64 may identify a distribution function of multiple temporal phase differences Δθ by curve fitting and calculate the mode based on fitting parameters. The distribution of multiple temporal phase differences Δθ may be a Poisson distribution, a log-normal distribution, a chi-squared distribution, a beta distribution, a Gaussian distribution, or the like. For example, when the distribution of the temporal phase differences Δθ is a Poisson distribution, the distribution function may be expressed as a probability density function P(X=k)=(λ ｋ e －λ ) / k!, the value corresponding to the fitting parameter λ is calculated as the mode, where P(X=k) is the probability that the random variable X occurs k times, and e is the base of the natural logarithm.

[0055] The blood glucose level calculation unit 64 may calculate the rate of fluctuation in blood glucose levels when the living organism 9 eats a meal. For example, the blood glucose level calculation unit 64 may determine that the living organism 9 has started eating based on the intake start information or the like received by the reception unit 61, and calculate the rate of fluctuation in blood glucose levels when the living organism 9 eats a meal. In this case, the blood glucose level calculation unit 64 may evaluate the risk of the living organism 9 developing diabetes by calculating the rate of fluctuation in blood glucose levels (ease of blood glucose level increase) of the living organism 9 using the blood glucose level of the living organism 9 while sleeping as a baseline. The blood glucose level calculation unit 64 may calculate various metabolic indices of the living organism 9 based on the blood glucose level.

[0056] Ingestion of a meal can cause a sudden rise and fall in blood glucose levels (blood glucose spikes). The blood glucose level calculation unit 64 may detect a blood glucose spike by determining whether the rate of increase in the blood glucose level calculated after a meal relative to the blood glucose level calculated before a meal is greater than a predetermined value. The blood glucose level calculation unit 64 may also detect the mealtime of the living body 9 based on the time when the blood glucose spike occurred.

[0057] The blood pressure value calculation unit 65, for example, causes the light output unit 3 and the light detection unit 4 to function as an optical blood pressure sensor to calculate the blood pressure value of the living body 9. The blood pressure value calculation unit 65 controls the light output unit 3 and the light detection unit 4 to output light L to the living body 9 and detect the intensity of the light L transmitted through the living body 9, thereby calculating the change in blood pressure over time (blood pressure waveform) from the change in blood volume over time that occurs at a predetermined position in the living body 9. The method for calculating the blood pressure value is not limited and may be, for example, the methods disclosed in Japanese Patent Nos. 6,482,412, 6,510,913, 6,636,784, 5,997,865, U.S. Pat. No. 11,154,206, 10,772,513, or 11,089,965. Typically, the blood pressure of the living body 9 fluctuates when the living body 9 eats food. The blood pressure value calculation unit 65 may calculate the rate of fluctuation (including the amount of fluctuation) in blood pressure values ​​when the living body 9 ingests a meal based on the meal time identified by the intake start information received by the receiving unit 61 or the meal time detected by the blood glucose value calculation unit 64.

[0058] The alertness detection unit 66 detects the alertness (degree of alertness) of the living body 9. The alertness is information indicating, for example, the type of sleep of the living body 9 (whether it is REM sleep or non-REM sleep, etc.), the level of movement of the living body 9 (whether it is at rest or exercising, etc.), or the type of movement (whether it is walking or running, etc.). The alertness detection unit 66 may detect the alertness by a known method using the body movement detection sensor 5.

[0059] The blood glucose level prediction unit 67 predicts the rate of change in blood glucose levels when the living organism 9 eats a meal, based on the content of the meal ingested by the living organism 9. The rate of change in blood glucose levels when the living organism 9 eats a meal varies depending on the content of the meal. The rate of change in blood glucose levels when a specific food is ingested is generally evaluated using an index such as the glycemic index (GI), and the rate of change in blood glucose levels after ingestion can be predicted based on the content of the meal ingested by the living organism 9. The blood glucose level prediction unit 67 predicts the rate of change in blood glucose levels when the living organism 9 eats a meal (calculates a predicted value of the rate of change), based on, for example, information on the content of the meal received by the receiving unit 61.

[0060] The information output unit 68 outputs information related to the blood glucose level calculated by the blood glucose level calculation unit 64. For example, the information output unit 68 outputs information by controlling an output device provided in the blood glucose level measuring device 1 or another terminal such as a user terminal connected to the blood glucose level measuring device 1 via a network or the like (hereinafter referred to as the blood glucose level measuring device 1, etc.). The blood glucose level information may be information indicating the numerical value of the blood glucose level fluctuation (fluctuation rate) per unit time or information indicating that the fluctuation amount exceeds a predetermined value, information indicating the numerical value (absolute value, etc.) of the blood glucose level or information indicating that the numerical value of the blood glucose level exceeds or falls below a predetermined value, or information indicating various metabolic indicators of the living body 9 calculated from the blood glucose level. Examples of output devices provided in the blood glucose level measuring device 1, etc. include a display, a speaker, a vibration generator, etc. Details of the output process of the blood glucose level information by the information output unit 68 will be described later. [Process for Acquiring Waveform Calculation Data]

[0061] A more detailed description will be given of the process of acquiring the waveform calculation data by the acquisition unit 62. The acquisition unit 62 is configured to be able to perform first sampling, which acquires the waveform calculation data at a first sampling rate, and second sampling, which acquires the waveform calculation data at a second sampling rate that is higher than the first sampling rate.

[0062] Specifically, when the first sampling is performed, the acquisition unit 62 controls the light output unit 3 and the light detection unit 4 so that the output of light L by the light output unit 3 and the detection of light L by the light detection unit 4 are performed at a first sampling rate, and acquires waveform calculation data (first data D1 and second data D2) at the first sampling rate. Similarly, when the second sampling is performed, the acquisition unit 62 controls the light output unit 3 and the light detection unit 4 so that the output of light L by the light output unit 3 and the detection of light L by the light detection unit 4 are performed at a second sampling rate, and acquires waveform calculation data at the second sampling rate. Because the second sampling rate is higher than the first sampling rate, the number of times light L is output per unit time when the second sampling is performed is greater than the number of times light L is output per unit time when the first sampling is performed.

[0063] In this example, the first sampling rate is 20 Hz or more and 60 Hz or less, and the second sampling rate is 100 Hz or more and 300 Hz or less. The frequency f2 of the second sampling rate may be calculated, for example, by f2 = (4000 / a) × f0 [Hz], where the required blood glucose measurement accuracy is ±a [mg / dl] and the pulse rate is f0 [Hz].

[0064] The acquisition unit 62 determines whether to perform the second sampling. The acquisition unit 62 may determine whether to perform the second sampling based on a predetermined condition. The acquisition unit 62 may also determine whether to end the execution of the second sampling based on a predetermined condition. In this embodiment, if the acquisition unit 62 determines not to perform the second sampling, the acquisition unit 62 performs the first sampling. Therefore, the determination by the acquisition unit 62 of whether to perform the second sampling can also be said to be a determination by the acquisition unit 62 of whether to perform the first sampling. Similarly, the determination of whether to end the execution of the second sampling can also be said to be a determination of whether to start the execution of the first sampling.

[0065] For example, the acquisition unit 62 may perform the second sampling at predetermined time intervals. That is, the acquisition unit 62 may determine to perform the second sampling when a predetermined time has elapsed since the previous second sampling ended. Alternatively, the acquisition unit 62 may determine to end the second sampling when a predetermined time has elapsed since the start of the second sampling.

[0066] As another example, the acquisition unit 62 measures data related to the heart rate of the living body 9 and determines whether to perform second sampling based on the data related to the heart rate. Furthermore, the acquisition unit 62 determines whether to terminate execution of second sampling based on the data related to the heart rate. The data related to the heart rate of the living body 9 may be, for example, the heart rate of the living body 9 or heart rate variability (HRV) as a stress index. HRV is data obtained by measuring the variation in the interval between heartbeats. The acquisition unit 62 may, for example, cause the light output unit 3 and the light detection unit 4 to function as an optical heart rate sensor and acquire the heart rate data using a known method. The acquisition unit 62 determines to perform second sampling when the data related to the heart rate of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to perform second sampling when the heart rate is equal to or greater than a predetermined value, or when stress indicated by the HRV is higher than a predetermined level. Furthermore, the acquisition unit 62 determines to terminate execution of second sampling when the data related to the heart rate of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may decide to terminate the execution of the second sampling when the heart rate falls below a predetermined value, or may decide to terminate the execution of the second sampling when the stress indicated by the HRV falls below a predetermined level.

[0067] As another example, the acquisition unit 62 measures data regarding the oxygen saturation of the living body 9 and determines whether to perform the second sampling based on the data regarding the oxygen saturation. Furthermore, the acquisition unit 62 determines whether to terminate the execution of the second sampling based on the data regarding the oxygen saturation. The data regarding the oxygen saturation of the living body 9 may be, for example, the oxygen saturation value (absolute value) of the living body 9. The acquisition unit 62 may, for example, cause the light output unit 3 and the light detection unit 4 to function as an optical oxygen saturation sensor and acquire the oxygen saturation data using a known method. The acquisition unit 62 determines to perform the second sampling when the data regarding the oxygen saturation of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to perform the second sampling when the oxygen saturation is equal to or lower than a predetermined value. Furthermore, the acquisition unit 62 determines to terminate the execution of the second sampling when the data regarding the oxygen saturation of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to terminate the execution of the second sampling when the oxygen saturation exceeds a predetermined value.

[0068] As another example, the acquisition unit 62 determines whether to perform the second sampling based on the alertness detected by the alertness detection unit 66. Furthermore, the acquisition unit 62 determines whether to end the execution of the second sampling based on the alertness detected by the alertness detection unit 66. For example, if the detected alertness is information indicating the type of sleep (REM sleep or non-REM sleep) of the living body 9, the acquisition unit 62 may determine to perform the second sampling when it is predicted that the end of sleep (wake-up) of the living body 9 is approaching based on the alertness. That is, the acquisition unit 62 may perform the second sampling in a time period before or after the wake-up of the living body 9. If the detected alertness is information indicating the level of exercise (whether the living body 9 is resting or exercising), the acquisition unit 62 may determine to perform the second sampling when it is predicted that the living body 9 is exercising based on the alertness. Furthermore, the acquisition unit 62 may determine to end the execution of the second sampling when it is predicted that the exercise of the living body 9 has ended based on the alertness. That is, the acquisition unit 62 may perform the second sampling while the living body 9 is exercising. The acquisition unit 62 may determine whether the living body 9 is taking a bath based on the detection result of the body motion detection sensor 5, and when it determines that the living body 9 is taking a bath, may decide to execute the second sampling. Alternatively, the acquisition unit 62 may determine whether the living body 9 has finished bathing based on the detection result of the body motion detection sensor 5, and when it determines that the bathing has finished, may decide to terminate the execution of the second sampling.

[0069] As another example, the acquisition unit 62 determines whether to perform the second sampling based on the information received by the reception unit 61. Furthermore, the acquisition unit 62 determines whether to end the execution of the second sampling based on the information received by the reception unit 61. For example, the acquisition unit 62 may determine to perform the second sampling when the reception unit 61 receives intake start information as a trigger. Furthermore, the acquisition unit 62 may end the execution of the second sampling when the reception unit 61 receives intake end information as a trigger. That is, the acquisition unit 62 may perform the second sampling while the living body 9 is eating. The acquisition unit 62 may perform the second sampling when the reception unit 61 receives exercise start information as a trigger. Furthermore, the acquisition unit 62 may end the execution of the second sampling when the reception unit 61 receives exercise end information as a trigger. That is, the acquisition unit 62 may perform the second sampling while the living body 9 is exercising. The acquisition unit 62 may determine to perform the second sampling when the reception unit 61 receives bathing start information as a trigger. The acquiring unit 62 may end the execution of the second sampling when the receiving unit 61 receives bathing end information as a trigger. That is, the acquiring unit 62 may perform the second sampling while the living body 9 is taking a bath.

[0070] As another example, the acquisition unit 62 determines whether to perform the second sampling based on the biometric information received by the receiving unit 61. Furthermore, the acquisition unit 62 determines whether to terminate the execution of the second sampling based on the biometric information received by the receiving unit 61. For example, if the biometric information received by the receiving unit 61 includes past mealtimes of the living body 9, the acquisition unit 62 may calculate a typical meal start time (e.g., an average start time) of the living body 9 based on the past mealtimes and determine to perform the second sampling at the calculated time. Furthermore, the acquisition unit 62 may calculate a typical meal end time (e.g., an average end time) of the living body 9 based on the past mealtimes and terminate the execution of the second sampling when a predetermined time has elapsed since the calculated time. That is, the acquisition unit 62 may perform the second sampling while the living body 9 is eating. If the biometric information received by the receiving unit 61 includes multiple past wake-up times of the living body 9, the acquisition unit 62 may calculate a typical wake-up time (e.g., an average wake-up time) of the living body 9 based on the past wake-up times and perform the second sampling at the calculated wake-up time. That is, the acquisition unit 62 may perform the second sampling when the living body 9 is waking up. [Output process of information related to blood glucose level]

[0071] The process of outputting information about blood glucose levels by the information output unit 68 will be described in more detail. The information output unit 68 may output information about blood glucose levels when the calculated blood glucose level satisfies a predetermined condition. The predetermined condition may be that the amount of fluctuation (fluctuation rate) in blood glucose levels per unit time exceeds a predetermined value, that the blood glucose level exceeds or falls below a predetermined value, or that a blood glucose spike is detected by the blood glucose level calculation unit 64. The predetermined condition may be determined using medically or statistically representative values, or may be arbitrarily determined by the user (living body 9) or administrator of the blood glucose level measuring device 1 with the advice of a qualified medical professional, for example. In this embodiment, the blood glucose level calculation unit 64 determines whether the calculated blood glucose level satisfies the predetermined condition. The blood glucose level calculation unit 64 may also estimate the risk or severity of the health condition of the living body 9 based on the blood glucose level. Estimation of the risk or severity of the health condition of the living body 9 may be performed as part of determining whether the blood glucose level satisfies the predetermined condition.

[0072] As an example of an information output mode, the information output unit 68 may output information related to the blood glucose level visually. For example, the information output unit 68 may display information related to the blood glucose level on a display of the blood glucose level measuring device 1 or the like. Specifically, the information output unit 68 may select and display an appropriate message from multiple messages, such as "Be careful," "Approaching a danger zone," or "Take immediate action," depending on the risk or severity of the health condition of the living body 9 estimated from the blood glucose level. The information output unit 68 may also display information for restoring the blood glucose level to an appropriate value. For example, if the blood glucose level is low, the information output unit 68 may display an advertisement for a food delivery service such as donuts to encourage the living body 9 to replenish its sugar intake. The information output unit 68 may change the brightness and flashing frequency of the display of the blood glucose level measuring device 1 depending on the risk or severity of the health condition of the living body 9 estimated from the blood glucose level. For example, if the risk is high, the information output unit 68 may flash the display at maximum brightness at high speed.

[0073] As another example, the information output unit 68 may output information about the blood glucose level by auditory means. For example, the information output unit 68 causes a speaker of the blood glucose level measuring device 1 or the like to output information about the blood glucose level. The information about the blood glucose level output from the speaker may be an alarm corresponding to the calculated blood glucose level. The information output unit 68 may output information about the blood glucose level at a specific volume and a specific rhythm. The specific volume may be a volume that increases as the risk or severity of the health condition of the living body 9 estimated from the blood glucose level increases. The specific rhythm may be, for example, a rhythm whose intervals become shorter as the risk or severity of the health condition of the living body 9 estimated from the blood glucose level increases, or an irregular or unstable rhythm that intentionally induces discomfort or anxiety in the living body 9 or those around the living body 9.

[0074] As another example, the information output unit 68 may output information about the blood glucose level by vibration. For example, the information output unit 68 causes a vibration generator of the blood glucose level measuring device 1 or the like to output information about the blood glucose level. For example, the information output unit 68 controls the vibration generator so that the blood glucose level measuring device 1 or the like vibrates at an intensity and rhythm corresponding to the risk or severity of the health state of the living body 9 estimated from the blood glucose level. The information output unit 68 may vibrate the blood glucose level measuring device 1 or the like at a specific intensity and a specific rhythm. The specific intensity may be an intensity that increases as the risk or severity of the health state of the living body 9 estimated from the blood glucose level increases. The specific rhythm may be, for example, a rhythm whose intervals become shorter as the risk or severity of the health state of the living body 9 estimated from the blood glucose level increases, or an irregular or unstable rhythm that intentionally induces discomfort or anxiety in the living body 9 or in those around the living body 9.

[0075] As another example, the information output unit 68 may notify information related to the blood glucose level by email, push notification, or the like to a user terminal connected via a network to the blood glucose measuring device 1 or another pre-registered terminal. The other terminal may be a terminal of the living body 9's family member, guardian, attending physician, registered dietitian, sports trainer, or a person in charge of the IT (Information Technology) department or HR (Human Resources) department of the company to which the living body 9 belongs.

[0076] The information output unit 68 may output information related to the blood pressure values ​​calculated by the blood pressure value calculation unit 65. The information output unit 68 may output information related to the blood pressure values ​​together with information related to the blood glucose levels. The information related to the blood pressure values ​​may be, for example, a systolic blood pressure value or a diastolic blood pressure value. The systolic blood pressure value is the highest systolic blood pressure value. The diastolic blood pressure value is the lowest diastolic blood pressure value. The information output unit 68 may output information related to the rate of change in the blood pressure values ​​when the living body 9 eats a meal, which is calculated by the blood pressure value calculation unit 65. For example, the information output unit 68 may output the degree of decrease in the blood pressure value when the living body 9 eats a meal.

[0077] The information output unit 68 may output the blood glucose fluctuation rate calculated by the blood glucose level calculation unit 64 when the living organism 9 eats a meal as information related to the blood glucose level. For example, the information output unit 68 may detect the waking up of the living organism 9 using the body motion detection sensor 5 and output the blood glucose fluctuation rate when the living organism 9 eats the first meal after waking up as information related to the blood glucose level. The blood glucose level calculation unit 64 may use the blood glucose level of the living organism 9 while sleeping as a reference level, evaluate the glucose tolerance of the living organism 9 based on the degree of increase in blood glucose level when the living organism 9 eats the first meal after waking up, and the information output unit 68 may output the evaluation result. In this case, the blood glucose level calculation unit 64 may evaluate glucose tolerance based on a metabolic index calculated from the blood glucose level instead of the blood glucose level.

[0078] The information output unit 68 may output information about the difference between the blood glucose fluctuation rate (predicted value) predicted by the blood glucose prediction unit 67 and the blood glucose fluctuation rate (calculated value) calculated by the blood glucose calculation unit 64 when the living body 9 ingests a meal, as information about the blood glucose level. The information about the difference may be the difference (absolute value) between the predicted value and the calculated value, information indicating that the difference exceeds a predetermined threshold, or information indicating that the calculated value is greater than the predicted value. If the calculated value is higher than the predicted value, the information output unit 68 may output the contents of the ingested meal and advice for suppressing the rate of increase in blood glucose level (such as the order in which food is ingested, the speed, and the number of chews). This allows the blood glucose measuring device 1 to present foods that are likely to increase blood glucose levels specifically for each individual, or to provide advice for suppressing the rate of increase in blood glucose level. [Blood Glucose Measurement Method]

[0079] Next, a blood glucose measurement method performed by the blood glucose measuring device 1 according to the first embodiment will be described. As shown in Fig. 6, first, the acquisition unit 62 performs first sampling (step S11). The acquisition unit 62 outputs light L to the living body 9 and detects the light L that has passed through the living body 9, thereby acquiring waveform calculation data (first data D1 and second data D2) at a first sampling rate.

[0080] Next, the phase difference calculation unit 63 calculates the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 based on the waveform calculation data acquired by the acquisition unit 62 in step S11 (step S12). Next, the phase difference calculation unit 63 calculates the temporal phase difference Δθ between the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 (step S13). Next, the blood glucose level calculation unit 64 calculates the blood glucose level of the living body 9 based on the temporal phase difference Δθ calculated by the phase difference calculation unit 63 (step S14).

[0081] Next, the information output unit 68 outputs information about the blood glucose level (step S15). The information output unit 68 may output information about the blood glucose level if the blood glucose level calculated in step S14 satisfies a predetermined condition. The predetermined condition may be, for example, that the amount of fluctuation in blood glucose level per unit time exceeds a predetermined value, that the blood glucose level exceeds or falls below a predetermined value, or that a blood glucose spike is detected by the blood glucose level calculation unit 64.

[0082] Next, the acquisition unit 62 determines whether to perform second sampling (step S16). The acquisition unit 62 determines whether to perform second sampling based on predetermined conditions. As described above, the acquisition unit 62 may determine whether to perform second sampling based on data related to the heart rate of the living body 9, the alertness level of the living body 9, or information received by the reception unit 61 (e.g., intake start information, exercise start information, biological information).

[0083] If the acquiring unit 62 determines to perform the second sampling in step S16 (step S16: Yes), the acquiring unit 62 performs the second sampling (step S17). Specifically, the acquiring unit 62 acquires waveform calculation data at a second sampling rate higher than the first sampling rate by outputting light L to the living body 9 and detecting the light L that has passed through the living body 9. If the acquiring unit 62 determines not to perform the second sampling in step S16 (step S16: No), the process returns to step S11. That is, the acquiring unit 62 performs the first sampling again.

[0084] Next, the phase difference calculation unit 63 calculates the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 based on the waveform calculation data acquired by the acquisition unit 62 in step S17 (step S18). Next, the phase difference calculation unit 63 calculates the temporal phase difference Δθ between the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 (step S19). Next, the blood glucose level calculation unit 64 calculates the blood glucose level of the living body 9 based on the temporal phase difference Δθ calculated by the phase difference calculation unit 63 (step S20).

[0085] Next, the information output unit 68 outputs information related to the blood glucose level (step S21). The information output unit 68 may output information related to the blood glucose level if the blood glucose level calculated in step S20 satisfies a predetermined condition. The predetermined condition may be the same as the condition described in step S15. After executing step S21, the acquisition unit 62 may again execute the process of determining whether or not to perform second sampling (step S16). This completes the blood glucose level calculation process by the blood glucose level measuring device 1. [Actions and Effects]

[0086] In the blood glucose level measuring device 1, the acquisition unit 62 is configured to perform first sampling, which acquires waveform calculation data at a first sampling rate, and second sampling, which acquires waveform calculation data at a second sampling rate higher than the first sampling rate. As a result, for example, at times when high blood glucose measurement accuracy is required, the acquisition unit 62 performs second sampling, thereby enabling blood glucose levels to be measured with high measurement accuracy. High measurement accuracy may be, for example, accuracy sufficient for the blood glucose level calculation unit 64 to detect blood glucose spikes. On the other hand, at times when high blood glucose measurement accuracy is not required, the acquisition unit 62 performs first sampling, thereby reducing the amount of power consumed to acquire waveform calculation data (e.g., the power required for the light output unit 3 to output light L) and thereby improving the operating time of the blood glucose level measuring device 1. Therefore, the blood glucose level measuring device 1 can measure blood glucose levels with high measurement accuracy and improve the operating time of the blood glucose level measuring device 1. For example, since the temporal phase difference Δθ between the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 decreases as the heart rate (pulse rate) of the living body 9 increases, a higher sampling rate is required to perform highly accurate measurements. Therefore, when the heart rate of the living body 9 is high, the acquisition unit 62 performs the second sampling, thereby enabling highly accurate measurements, while when the heart rate is low, the acquisition unit 62 performs the first sampling, thereby improving the operating time of the blood glucose measuring device 1.

[0087] In the blood glucose level measuring device 1, the first sampling rate is 20 Hz or more and 60 Hz or less. In this case, it is possible to calculate an approximate blood glucose level even when performing the first sampling, and the operating time of the blood glucose level measuring device 1 can be further improved. The lighting frequency of the light source (e.g., an LED for measuring pulse rate) mounted on a typical smartwatch is approximately 20 Hz, and the frame rate when capturing video with a camera mounted on a typical smartphone is approximately 60 fps (=60 Hz). Therefore, the first sampling can be performed using the light source mounted on a typical smartwatch or the camera mounted on a smartphone.

[0088] In the blood glucose measuring device 1, the second sampling rate is 100 Hz or more and 300 Hz or less. In this case, blood glucose levels can be measured with higher measurement accuracy when the second sampling is performed. For example, by setting the second sampling rate to 250 Hz or more, the measurement accuracy of ±15 mg / dL required for medical blood glucose meters can be achieved.

[0089] In the blood glucose level measuring device 1, the phase difference calculation unit 63 may calculate multiple temporal phase differences Δθ, and the blood glucose level calculation unit 64 may calculate an average temporal phase difference ΔθA by performing an averaging process on the multiple temporal phase differences Δθ, and calculate the blood glucose level based on the average temporal phase difference ΔθA. In this case, noise contained in the calculated temporal phase differences Δθ is reduced, and the blood glucose level can be calculated based on a more reliable temporal phase difference Δθ (average temporal phase difference ΔθA). In particular, when first sampling is performed at a first sampling rate lower than the second sampling rate, the averaging process is effective because it can improve the blood glucose level measurement accuracy by removing noise.

[0090] In the blood glucose level measuring device 1, the acquiring unit 62 may acquire data related to the heartbeat of the living body 9 and determine whether to perform second sampling based on the data related to the heartbeat. In this case, the second sampling, which can measure blood glucose levels with higher measurement accuracy than the first sampling, can be performed at an appropriate timing based on the data related to the heartbeat.

[0091] The blood glucose measuring device 1 may include a wakefulness detection unit 66 that detects the wakefulness of the living body 9, and the acquisition unit 62 may determine whether to perform the second sampling based on the wakefulness. In this case, the second sampling, which can measure the blood glucose level with higher measurement accuracy than the first sampling, can be performed at an appropriate timing based on the wakefulness of the living body 9.

[0092] The blood glucose level measuring device 1 may include a receiving unit 61 that receives intake start information indicating that the living body 9 has started eating, and the acquiring unit 62 may perform the second sampling in response to the receipt of the intake start information by the receiving unit 61. In this case, the second sampling, which can measure blood glucose levels with higher measurement accuracy than the first sampling, can be performed when the living body 9 is eating, a time when blood glucose levels are likely to change.

[0093] The blood glucose measuring device 1 may include a receiving unit 61 that receives exercise start information indicating that the living body 9 has started exercising, and the acquiring unit 62 may perform the second sampling in response to the receipt of the exercise start information by the receiving unit 61. In this case, the second sampling, which can measure blood glucose levels with higher measurement accuracy than the first sampling, can be performed when the living body 9 is exercising, a time when blood glucose levels are likely to change.

[0094] The blood glucose level measuring device 1 includes an information output unit 68 that outputs information related to the blood glucose level, thereby making it possible to notify the living body 9 or the like of information related to the blood glucose level.

[0095] In the blood glucose level measuring device 1, the information output unit 68 may output information related to the blood glucose level when the amount of fluctuation in the blood glucose level exceeds a predetermined value. In this case, for example, it is possible to notify the living body 9 that the risk or seriousness of the health condition of the living body 9 is increasing due to the amount of fluctuation in the blood glucose level exceeding the predetermined value.

[0096] The blood glucose level measuring device 1 may include a blood pressure value calculation unit 65 that calculates the blood pressure value of the living body 9, and the information output unit 68 may output information related to the blood pressure value. In this case, the information related to the blood pressure value can be notified to the living body 9, etc.

[0097] In the blood glucose level measuring device 1, the blood glucose level calculation unit 64 may calculate the rate of fluctuation in blood glucose level when the living organism 9 takes a meal, and the information output unit 68 may output information related to the rate of fluctuation as information related to the blood glucose level. In this case, the living organism 9 can be notified of the rate of fluctuation in blood glucose level when the living organism 9 takes a meal.

[0098] According to the blood glucose level measurement method of the first embodiment, for the reasons described above, it is possible to measure blood glucose levels with high measurement accuracy and to improve the operating time of the blood glucose level measurement device 1. [Modification of the first embodiment]

[0099] Next, a description will be given of a modified example (first modified example) of the blood glucose measuring device 1 according to the first embodiment. In the first modified example, the acquiring unit 62 is configured to further perform third sampling, which acquires waveform calculation data at a third sampling rate that is higher than the first sampling rate and lower than the second sampling rate.

[0100] When the third sampling is performed, the acquisition unit 62 controls the light output unit 3 and the light detection unit 4 so that the output of light L by the light output unit 3 and the detection of light L by the light detection unit 4 are performed at the third sampling rate, and acquires waveform calculation data at the third sampling rate. Because the third sampling rate is higher than the first sampling rate, the number of times light L is output per unit time when the third sampling is performed is greater than the number of times it is output when the first sampling is performed. On the other hand, because the third sampling rate is lower than the second sampling rate, the number of times light L is output per unit time when the third sampling is performed is less than the number of times it is output when the second sampling is performed. In this example, the third sampling rate is equal to or greater than 50 Hz and equal to or less than 120 Hz.

[0101] The order in which the acquiring unit 62 performs the first sampling, the second sampling, and the third sampling is not limited. As an example, the acquiring unit 62 may perform the first sampling and then the third sampling, and may perform the third sampling and then the second sampling. As another example, the acquiring unit 62 may perform the first sampling and then the second sampling, and may perform the second sampling and then the third sampling.

[0102] The acquisition unit 62 determines whether to perform the third sampling based on predetermined conditions. The information or data used when determining whether to perform the third sampling may be the same as the information or data used to determine whether to perform the second sampling described above. The acquisition unit 62 may determine whether to perform the third sampling using conditions (criteria) different from the conditions (criteria) used when determining whether to perform the second sampling. For example, conditions may be set such that the first sampling, the third sampling, and the second sampling are switched in this order (so that the sampling rate increases) as the risk or severity of the health state of the living body 9 estimated from the blood glucose level increases.

[0103] For example, when the acquisition unit 62 determines whether to perform the second sampling and the third sampling based on data regarding the heart rate of the living body 9, the conditions may be set so that the third sampling is performed when the heart rate is equal to or greater than a first predetermined value, and the second sampling is performed when the heart rate is equal to or greater than a second predetermined value that is greater than the first predetermined value.

[0104] In the blood glucose measuring device 1 according to the first modification, the acquiring unit 62 is further configured to perform third sampling, which acquires waveform calculation data at a third sampling rate that is higher than the first sampling rate and lower than the second sampling rate. As a result, when the third sampling is performed, the blood glucose level can be measured with higher measurement accuracy than when the first sampling is performed, and the operating time of the blood glucose measuring device 1 can be improved compared to when the second sampling is performed. A variety of sampling methods suitable for various situations can be provided to the user of the blood glucose measuring device 1.

[0105] In the blood glucose level measuring device 1, the third sampling rate is 50 Hz or more and 120 Hz or less. In this case, when the third sampling is performed, blood glucose levels can be measured with a relatively high degree of accuracy, and the power consumption of the blood glucose level measuring device 1 can be reduced. [Second embodiment]

[0106] Next, a blood glucose measuring device 1 according to a second embodiment will be described. Differences between the second embodiment and the first embodiment will be mainly described below, and explanations of commonalities with the first embodiment may be omitted. The acquisition unit 62 of the blood glucose measuring device 1 according to the second embodiment is configured to be able to execute a first mode in which sampling (high-speed sampling) is repeatedly performed at a first frequency to acquire waveform calculation data at a sampling rate of 50 Hz or higher, and a second mode in which high-speed sampling is repeatedly performed at a second frequency higher than the first frequency.

[0107] In the first mode, the acquisition unit 62 repeatedly performs high-speed sampling of the waveform calculation data (first data D1 and second data D2) at a first frequency by controlling the light output unit 3 and the light detection unit 4. In the second mode, the acquisition unit 62 repeatedly performs high-speed sampling of the waveform calculation data at a second frequency by controlling the light output unit 3 and the light detection unit 4.

[0108] In both the first mode and the second mode, during a period when high-speed sampling is not being performed, the acquisition unit 62 may not acquire waveform calculation data, or may perform sampling (low-speed sampling) to acquire waveform calculation data at a sampling rate lower than 50 Hz. Because the second frequency is higher than the first frequency, the number of times light L is output per unit time when the second mode is performed is greater than the number of times light L is output per unit time when the first mode is performed. In both the first mode and the second mode, the duration of one high-speed sampling may be, for example, one second or more and six seconds or less. In this example, the first frequency is a frequency at which high-speed sampling is performed at intervals of five minutes or more, and the second frequency is a frequency at which high-speed sampling is performed at intervals of three minutes or less.

[0109] The acquisition unit 62 determines whether to execute the second mode. The acquisition unit 62 may determine whether to execute the second mode based on a predetermined condition. The acquisition unit 62 may also determine whether to end execution of the second mode based on a predetermined condition. In the present embodiment, if the acquisition unit 62 determines not to execute the second mode, the acquisition unit 62 executes the first mode. Therefore, the determination by the acquisition unit 62 of whether to execute the second mode can also be considered as a determination by the acquisition unit 62 of whether to execute the first mode. Similarly, the determination of whether to end execution of the second mode can also be considered as a determination of whether to start execution of the first mode.

[0110] For example, the acquisition unit 62 may execute the second mode at predetermined time intervals. That is, the acquisition unit 62 may determine to execute the second mode when a predetermined time has elapsed since the previous execution of the second mode ended. Furthermore, the acquisition unit 62 may determine to end the execution of the second mode when a predetermined time has elapsed since the execution of the second mode started.

[0111] As another example, the acquisition unit 62 measures data related to the heart rate of the living body 9 and determines whether to execute the second mode based on the data related to the heart rate. Furthermore, the acquisition unit 62 determines whether to terminate execution of the second mode based on the data related to the heart rate. The acquisition unit 62 may acquire data related to the heart rate using the method described in the first embodiment. The acquisition unit 62 determines to execute the second mode when the data related to the heart rate of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to execute the second mode when the heart rate is equal to or higher than a predetermined value, or when stress indicated by HRV is higher than a predetermined level. Furthermore, the acquisition unit 62 determines to terminate execution of the second mode when the data related to the heart rate of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to terminate execution of the second mode when the heart rate falls below a predetermined value, or when stress indicated by HRV falls below a predetermined level.

[0112] As another example, the acquisition unit 62 measures data related to the oxygen saturation of the living body 9 and determines whether to execute the second mode based on the data related to the oxygen saturation. The acquisition unit 62 also determines whether to terminate execution of the second mode based on the data related to the oxygen saturation. The data related to the oxygen saturation of the living body 9 may be, for example, the oxygen saturation value of the living body 9. The acquisition unit 62 may acquire the oxygen saturation data using the method described in the first embodiment. The acquisition unit 62 determines to execute the second mode when the data related to the oxygen saturation of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to execute the second mode when the oxygen saturation is equal to or lower than a predetermined value. The acquisition unit 62 also determines to terminate execution of the second mode when the data related to the oxygen saturation of the living body 9 satisfies a predetermined condition. For example, the acquisition unit 62 may determine to terminate execution of the second mode when the oxygen saturation exceeds a predetermined value.

[0113] As another example, the acquisition unit 62 determines whether to execute the second mode based on the alertness detected by the alertness detection unit 66. Furthermore, the acquisition unit 62 determines whether to terminate execution of the second mode based on the alertness detected by the alertness detection unit 66. For example, if the detected alertness is information indicating the type of sleep (REM sleep or non-REM sleep) of the living body 9, the acquisition unit 62 may determine to execute the second mode when it is predicted that the end of sleep (wake-up) of the living body 9 is approaching based on the alertness. That is, the acquisition unit 62 may execute the second mode in a time period before or after the wake-up of the living body 9. If the detected alertness is information indicating the level of exercise (whether the living body 9 is resting or exercising), the acquisition unit 62 may determine to execute the second mode when it is predicted that the living body 9 is exercising based on the alertness. Furthermore, the acquisition unit 62 may determine to terminate execution of the second mode when it is predicted that the exercise of the living body 9 has ended based on the alertness. That is, the acquisition unit 62 may execute the second mode while the living body 9 is exercising. The acquisition unit 62 may determine whether the living body 9 is taking a bath based on the detection result of the body motion detection sensor 5, and when it determines that the living body 9 is taking a bath, may decide to execute the second mode. Alternatively, the acquisition unit 62 may determine whether the living body 9 has finished bathing based on the detection result of the body motion detection sensor 5, and when it determines that the bathing has finished, may decide to end the execution of the second mode.

[0114] As another example, the acquisition unit 62 determines whether to execute the second mode based on the information received by the reception unit 61. Furthermore, the acquisition unit 62 determines whether to terminate execution of the second mode based on the information received by the reception unit 61. For example, the acquisition unit 62 may determine to execute the second mode when the reception unit 61 receives intake start information as a trigger. Furthermore, the acquisition unit 62 may terminate execution of the second mode when the reception unit 61 receives intake end information as a trigger. That is, the acquisition unit 62 may execute the second mode while the living body 9 is eating. The acquisition unit 62 may determine to execute the second mode when the reception unit 61 receives exercise start information as a trigger. Furthermore, the acquisition unit 62 may terminate execution of the second mode when the reception unit 61 receives exercise end information as a trigger. That is, the acquisition unit 62 may execute the second mode when the living body 9 is exercising. The acquisition unit 62 may determine to execute the second mode when the reception unit 61 receives bathing start information as a trigger. The acquisition unit 62 may terminate the execution of the second mode when the reception unit 61 receives bathing end information as a trigger. That is, the acquisition unit 62 may execute the second mode while the living body 9 is taking a bath.

[0115] As another example, the acquisition unit 62 determines whether to execute the second mode based on the biometric information received by the reception unit 61. Furthermore, the acquisition unit 62 determines whether to terminate execution of the second mode based on the biometric information received by the reception unit 61. For example, if the biometric information received by the reception unit 61 includes past mealtimes of the living body 9, the acquisition unit 62 may calculate a typical meal start time (e.g., an average start time) of the living body 9 based on the past mealtimes and determine to execute the second mode at the calculated time. Furthermore, the acquisition unit 62 may calculate a typical meal end time (e.g., an average end time) of the living body 9 based on the past mealtimes and terminate execution of the second mode when a predetermined time has elapsed since the calculated time. In other words, the acquisition unit 62 may execute the second mode while the living body 9 is eating. If the biometric information received by the reception unit 61 includes multiple past wake-up times of the living body 9, the acquisition unit 62 may calculate a typical wake-up time (e.g., an average wake-up time) of the living body 9 based on the past wake-up times and execute the second mode at the calculated wake-up time. That is, the acquisition unit 62 may execute the second mode when the living body 9 wakes up.

[0116] Next, a blood glucose measurement method performed by the blood glucose measuring device 1 according to the second embodiment will be described. As shown in FIG. 7 , first, the acquisition unit 62 performs high-speed sampling (step S31). The acquisition unit 62 outputs light L to the living body 9 and detects the light L transmitted through the living body 9 to acquire waveform calculation data (first data D1 and second data D2) at a sampling rate of 50 Hz or higher. Step S31 corresponds to the high-speed sampling performed by the acquisition unit 62 when the first mode is executed. That is, the high-speed sampling performed in step S31 corresponds to one high-speed sampling cycle repeatedly performed by the acquisition unit 62 at a first frequency. The duration of one high-speed sampling cycle may be 1 second or more and 6 seconds or less.

[0117] Next, the phase difference calculation unit 63 calculates the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 based on the waveform calculation data acquired by the acquisition unit 62 in step S31 (step S32). Next, the phase difference calculation unit 63 calculates the temporal phase difference Δθ between the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 (step S33). Next, the blood glucose level calculation unit 64 calculates the blood glucose level of the living body 9 based on the temporal phase difference Δθ calculated by the phase difference calculation unit 63 (step S34).

[0118] Next, the information output unit 68 outputs information about the blood glucose level (step S35). The information output unit 68 may output information about the blood glucose level when the blood glucose level calculated in step S34 satisfies a predetermined condition. The predetermined condition may be that the amount of fluctuation in the blood glucose level per unit time exceeds a predetermined value, that the blood glucose level exceeds or falls below a predetermined value, or that a blood glucose spike is detected by the blood glucose level calculation unit 64. As described above, the high-speed sampling in step S31 is repeatedly performed at a first frequency. Furthermore, the processes from step S32 to step S35 are performed following step S31 and each time step S31 is performed. In other words, the processes from step S31 to step S35 are repeatedly performed at a first frequency.

[0119] Next, the acquisition unit 62 determines whether to execute the second mode (step S36). The process of step S36 may be executed after the processes of steps S31 to S35 (high-speed sampling) have been repeated a predetermined number of times, or may be executed each time the processes of steps S31 to S35 have been executed. The acquisition unit 62 determines whether to execute the second mode based on predetermined conditions. As described above, the acquisition unit 62 may determine whether to execute the second mode based on data related to the heart rate of the living body 9, the alertness level of the living body 9, or information received by the reception unit 61 (e.g., intake start information, exercise start information, biological information).

[0120] If the acquisition unit 62 determines to execute the second mode in step S36 (step S36: Yes), the acquisition unit 62 executes high-speed sampling (step S37). Specifically, the acquisition unit 62 acquires waveform calculation data at a sampling rate of 50 Hz or higher by outputting light L to the living body 9 and detecting the light L transmitted through the living body 9. Step S37 corresponds to the high-speed sampling performed by the acquisition unit 62 when the second mode is executed. That is, the high-speed sampling performed in step S37 corresponds to one high-speed sampling session repeatedly performed by the acquisition unit 62 at a second frequency higher than the first frequency. The duration of one high-speed sampling session may be 1 second or more and 6 seconds or less. If the acquisition unit 62 determines not to execute the second mode in step S36 (step S36: No), the process returns to step S31. That is, the acquisition unit 62 continues to execute high-speed sampling at the first frequency.

[0121] Next, the phase difference calculation unit 63 calculates the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 based on the waveform calculation data acquired by the acquisition unit 62 in step S37 (step S38). Next, the phase difference calculation unit 63 calculates the temporal phase difference Δθ between the oxygenated hemoglobin waveform P1 and the deoxygenated hemoglobin waveform P2 (step S39). Next, the blood glucose level calculation unit 64 calculates the blood glucose level of the living body 9 based on the temporal phase difference Δθ calculated by the phase difference calculation unit 63 (step S40).

[0122] Next, the information output unit 68 outputs information related to the blood glucose level (step S41). The information output unit 68 may output information related to the blood glucose level if the blood glucose level calculated in step S40 satisfies a predetermined condition. The predetermined condition may be the same as the condition described in step S35. As described above, the high-speed sampling in step S37 is repeatedly performed at the second frequency. Furthermore, the processes from step S38 to step S41 are performed each time step S37 is performed. That is, the processes from step S37 to step S41 are repeatedly performed at the second frequency. The acquisition unit 62 may perform the process of step S36 after the processes from step S37 to step S41 have been repeated a predetermined number of times, or may perform the process each time the processes from step S37 to step S41 are performed. This concludes the blood glucose level calculation process by the blood glucose level measuring device 1 according to the second embodiment.

[0123] In the blood glucose level measuring device 1 according to the second embodiment, the acquiring unit 62 is configured to be able to execute a first mode in which high-speed sampling is repeatedly performed at a first frequency and a second mode in which high-speed sampling is repeatedly performed at a second frequency higher than the first frequency. As a result, for example, when high-accuracy blood glucose level measurements are required frequently, the acquiring unit 62 executes the second mode, thereby enabling high-accuracy and frequent blood glucose level measurements. On the other hand, when high-accuracy measurements are not required frequently, the acquiring unit 62 executes the first mode, thereby reducing the amount of power consumed to acquire waveform calculation data (e.g., the power required for the optical output unit 3 to output light L) and thereby improving the operating time of the blood glucose level measuring device 1. Therefore, the blood glucose level measuring device 1 according to the second embodiment can measure blood glucose levels with high accuracy and improve the operating time of the blood glucose level measuring device 1.

[0124] In the blood glucose level measuring device 1, the first frequency is a frequency at which high-speed sampling is performed at intervals of 5 minutes or more, thereby enabling the operating time of the blood glucose level measuring device 1 to be further improved.

[0125] In the blood glucose level measuring device 1, the second frequency is a frequency at which high-speed sampling is performed at intervals of 3 minutes or less. This allows the blood glucose level to be calculated appropriately at times when blood glucose level measurement with high measurement accuracy is required frequently.

[0126] In the blood glucose measuring device 1, the acquiring unit 62 may acquire data related to the heartbeat of the living body 9 and determine whether or not to execute the second mode based on the data related to the heartbeat. In this case, the second mode, in which high-speed sampling is performed more frequently than in the first mode, can be executed at an appropriate timing based on the data related to the heartbeat.

[0127] In the blood glucose measuring device 1, the acquisition unit 62 may determine whether to execute the second mode based on the level of alertness. In this case, the second mode, in which high-speed sampling is performed more frequently than in the first mode, can be executed at an appropriate timing based on the level of alertness of the living body 9.

[0128] According to the blood glucose level measurement method of the second embodiment, for the reasons described above, it is possible to measure blood glucose levels with high measurement accuracy and to improve the operating time of the blood glucose level measurement device 1.

[0129] The present disclosure is not limited to the above-described embodiments and variations. The values ​​of the first sampling rate, the second sampling rate, and the third sampling rate are not limited to the above-described values. For example, the first sampling rate may be 30 Hz to 60 Hz, or 50 Hz to 60 Hz. The second sampling rate may be 100 Hz to 1 kHz, or 120 Hz to 1 kHz, or 100 Hz to 250 Hz, or 120 Hz to 250 Hz, or 180 Hz to 240 Hz. The third sampling rate may be 90 Hz to 120 Hz, or 90 Hz to 100 Hz.

[0130] The values ​​of the first frequency and the second frequency are not limited to the above values. For example, the first frequency may be a frequency at which high-speed sampling is performed at intervals of 10 minutes or more, 15 minutes or more, or 30 minutes or more. The second frequency may be a frequency at which high-speed sampling is performed at intervals of 2 minutes or less, 1 minute or less, or 30 seconds or less.

[0131] The blood glucose level calculation unit 64 may calculate the blood glucose level based on the average temporal phase difference ΔθA when at least one specific sampling among the first sampling and the second sampling (the first to third samplings in the first modified example) is being performed, and may not calculate the blood glucose level based on the average temporal phase difference ΔθA when other samplings are being performed. For example, the blood glucose level calculation unit 64 may calculate the blood glucose level based on the average temporal phase difference ΔθA when the acquisition unit 62 is performing the first sampling, and may not calculate the blood glucose level based on the average temporal phase difference ΔθA when the acquisition unit 62 is performing the second sampling.

[0132] In the above embodiment, the ECU 6 is provided in the main body 2, but the ECU 6 does not have to be provided in the main body 2. The ECU 6 may be provided in, for example, a server that can communicate with the main body 2. In this case, the main body 2, the light output unit 3, the light detection unit 4, the body motion detection sensor 5, and the ECU 6 are each part of the blood glucose measurement system.

[0133] 1...blood glucose level measuring device, 61...receiving section, 62...acquiring section, 63...phase difference calculating section, 64...blood glucose level calculating section, 66...awakening level detecting section, 68...information output section.

Claims

1. A blood glucose measuring device comprising: an acquisition unit that acquires waveform calculation data for calculating an oxygenated hemoglobin waveform relating to the oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to the deoxygenated hemoglobin concentration in the blood of the living body by emitting light to the living body and detecting the light that has passed through the living body; a phase difference calculation unit that calculates the temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and a blood glucose calculation unit that calculates the blood glucose level of the living body based on the temporal phase difference, wherein the acquisition unit is configured to perform first sampling that acquires the waveform calculation data at a first sampling rate and second sampling that acquires the waveform calculation data at a second sampling rate that is higher than the first sampling rate.

2. The blood glucose measuring device according to claim 1, wherein the first sampling rate is equal to or greater than 20 Hz and equal to or less than 60 Hz.

3. The blood glucose measuring device according to claim 1 or 2, wherein the second sampling rate is equal to or greater than 100 Hz and equal to or less than 300 Hz.

4. A blood glucose measuring device according to any one of claims 1 to 3, wherein the acquisition unit is further configured to be able to perform third sampling, which acquires the waveform calculation data at a third sampling rate that is higher than the first sampling rate and lower than the second sampling rate.

5. The blood glucose measuring device according to claim 4, wherein the third sampling rate is equal to or greater than 50 Hz and equal to or less than 120 Hz.

6. A blood glucose measuring device according to any one of claims 1 to 5, wherein the phase difference calculation unit calculates a plurality of temporal phase differences, each of which is the temporal phase difference; and the blood glucose calculation unit calculates an average temporal phase difference by performing an averaging process on the plurality of temporal phase differences, and calculates the blood glucose level based on the average temporal phase difference.

7. The blood glucose measuring device according to any one of claims 1 to 6, wherein the acquisition unit further acquires data relating to the heart rate of the living body, and determines whether or not to perform the second sampling based on the data relating to the heart rate.

8. A blood glucose measuring device according to any one of claims 1 to 7, further comprising an alertness detection unit that detects the alertness of the living body, and the acquisition unit determines whether or not to perform the second sampling based on the alertness.

9. A blood glucose measuring device according to any one of claims 1 to 8, further comprising a reception unit that receives intake start information indicating that the living body has started to take in food, and wherein the acquisition unit executes the second sampling when the reception unit receives the intake start information.

10. A blood glucose measuring device as described in any one of claims 1 to 9, further comprising a reception unit that receives exercise start information indicating that the living body has started exercising, and the acquisition unit performs the second sampling when the reception unit receives the exercise start information.

11. A blood glucose measuring device comprising: an acquisition unit that acquires waveform calculation data for calculating an oxygenated hemoglobin waveform relating to the oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to the deoxygenated hemoglobin concentration in the blood of the living body by emitting light to the living body and detecting the light that has passed through the living body; a phase difference calculation unit that calculates the temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and a blood glucose calculation unit that calculates the blood glucose level of the living body based on the temporal phase difference, wherein the acquisition unit is configured to be able to execute a first mode in which sampling is repeated at a first frequency to acquire the waveform calculation data at a sampling rate of 50 Hz or more, and a second mode in which the sampling is repeated at a second frequency higher than the first frequency.

12. The blood glucose measuring device according to claim 11, wherein the first frequency is a frequency at which the sampling is performed at intervals of 5 minutes or more.

13. The blood glucose measuring device according to claim 11 or 12, wherein the second frequency is a frequency at which the sampling is performed at intervals of 3 minutes or less.

14. The blood glucose measuring device according to any one of claims 11 to 13, wherein the acquisition unit acquires data relating to the heart rate of the living body and determines whether or not to execute the second mode based on the data relating to the heart rate.

15. A blood glucose measuring device according to any one of claims 11 to 14, further comprising an alertness detection unit that calculates the alertness of the living body, and the acquisition unit determines whether or not to execute the second mode based on the alertness.

16. The blood glucose level measuring device according to any one of claims 1 to 15, further comprising an information output unit that outputs information relating to the blood glucose level.

17. The blood glucose level measuring device according to claim 16, wherein the information output unit outputs information about the blood glucose level when the amount of fluctuation in the blood glucose level exceeds a predetermined value.

18. A blood glucose measuring device according to claim 16 or 17, further comprising a blood pressure value calculation unit that calculates the blood pressure value of the living body, and the information output unit outputs information relating to the blood pressure value.

19. A blood glucose measuring device as described in any one of claims 16 to 18, wherein the blood glucose calculation unit calculates the rate of fluctuation of the blood glucose level when the living body ingests a meal, and the information output unit outputs information regarding the rate of fluctuation as information regarding the blood glucose level.

20. A blood glucose measurement method comprising the steps of: acquiring waveform calculation data for calculating an oxygenated hemoglobin waveform relating to the oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to the deoxygenated hemoglobin concentration in the blood of the living body by outputting light to the living body and detecting the light that has passed through the living body; calculating a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and calculating the blood glucose level of the living body based on the temporal phase difference, wherein the acquiring step performs first sampling to acquire the waveform calculation data at a first sampling rate, or second sampling to acquire the waveform calculation data at a second sampling rate higher than the first sampling rate.

21. A blood glucose measurement method comprising the steps of: acquiring waveform calculation data for calculating an oxygenated hemoglobin waveform relating to the oxygenated hemoglobin concentration in the blood of the living body and a deoxygenated hemoglobin waveform relating to the deoxygenated hemoglobin concentration in the blood of the living body by outputting light to the living body and detecting the light that has passed through the living body; calculating a temporal phase difference between the oxygenated hemoglobin waveform and the deoxygenated hemoglobin waveform; and calculating the blood glucose level of the living body based on the temporal phase difference, wherein the acquiring step executes a first mode in which sampling is repeatedly performed at a first frequency to acquire the waveform calculation data at a sampling rate of 50 Hz or more, or a second mode in which the sampling is repeatedly performed at a second frequency higher than the first frequency.

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