Biological signal measurement device, method, and computer-readable recording medium having a program recorded thereon

Abstract

The biological signal measurement device, method, and program of the present invention can be used for a long time without causing the device to be enlarged or weighted, and can reliably measure biological signals. One aspect of the present invention obtains a first biological signal related to the pulsation of the heart of a subject from a first sensor, and obtains a second biological signal related to the pulsation of the heart of the subject from a second sensor, detects a first feature amount from the obtained first biological signal, sets a light emission control mode based on the detection timing of the first feature amount and information indicating the time correlation between the first biological signal and the second biological signal, and intermittently drives the light emitting element of the second sensor to emit light according to the set light emission control mode.

Description

Technical Field

[0001] One aspect of the present invention relates to, for example, a biological signal measuring device, a method, and a computer-readable recording medium having a program for measuring a biological signal of a person. Background Art

[0002] As one of biological signals, for example, a pulse wave is known. The pulse wave is a periodic waveform signal generated by the vibration of the large artery according to the pulsation of the heart. The pulse wave velocity (PWV) of the pulse wave flowing through the artery is correlated with the volume elastic modulus of the blood vessel. Since the volume elastic modulus increases as the blood pressure increases, the blood pressure and the development of arteriosclerosis can be estimated by obtaining the pulse wave velocity. The pulse wave velocity can be obtained, for example, by measuring the time taken for the pulse wave to propagate between two different points on the artery, that is, the pulse transit time (PTT).

[0003] Furthermore, as a technique for measuring the above-mentioned pulse transit time (PTT), for example, a technique is known as follows: As described in Patent Document 1, when measuring blood pressure, the pulse transit time is calculated based on the output of an electrocardiogram (ECG) sensor attached to a person's body and the output of a photoelectric sensor using the photoplethysmography (PPG) method attached to the ear. In addition, as another measurement technique, for example, a technique is also known as described in Patent Document 2, in which when measuring blood pressure, PPG sensors are respectively arranged at two different points on the artery and the pulse transit time is calculated based on the pulse waves measured by these sensors.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent No. 5984088

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 7-327940 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, in a PPG sensor for measuring the pulse wave conduction time, a light emitting diode (LED) is generally used as the light emitting element. Compared with other biological sensors such as an ECG sensor, the PPG sensor has a large power consumption. Therefore, for example, when a sphygmomanometer using a PPG sensor is used to continuously measure blood pressure during sleep (e.g., for 8 hours), the battery capacity may be insufficient to perform the measurement throughout the measurement period of the subject. On the other hand, although the above-mentioned adverse conditions can be avoided by increasing the battery capacity, in this case, due to the enlargement and weight increase of the battery, the device becomes larger, resulting in other problems such as impairing the advantages of a wearable sphygmomanometer.

[0010] The present invention has been completed in view of the above circumstances. As one aspect, it is intended to provide a technique that can be used for a long time without causing enlargement and weight increase of the device and can reliably measure biological signals.

[0011] Technical Solution

[0012] One aspect of the biological signal measurement device or biological signal measurement method of the present invention is configured to obtain a first biological signal related to the pulsation of the heart of the subject from a first sensor, and obtain a second biological signal related to the pulsation of the heart of the subject from a second sensor using a light emitting element, detect a first characteristic quantity from the obtained first biological signal, and intermittently drive the light emitting element of the second sensor to emit light based on the detection timing of the first characteristic quantity and information indicating the time correlation between the first biological signal and the second biological signal.

[0013] Advantages of the Invention

[0014] According to one aspect of the present invention, the light emitting element of the second sensor is intermittently driven to emit light. Therefore, compared with the case where the light emitting element continuously emits light, the power consumption can be reduced. Moreover, the light emitting period of the above intermittent light emission driving is synchronized with the detection timing of the characteristic quantity of the first biological signal measured from the same subject, and is set based on the time correlation between the first biological signal and the second biological signal. Therefore, the characteristic quantity of the second biological signal can be reliably detected without omission.

[0015] That is, according to one aspect of the present invention, a technique that can be used for a long time without causing enlargement and weight increase of the device and can reliably measure biological signals can be provided. Description of the Drawings

[0016] Figure 1This is a diagram showing an example of the overall configuration of a blood pressure measurement device as a first embodiment of the biological signal measurement device of the present invention.

[0017] Figure 2 It shows Figure 1 a diagram showing an example of the configuration of the surface side of the attachment unit of the blood pressure measurement device shown.

[0018] Figure 3 It shows Figure 1 a diagram showing an example of the configuration of the back side of the attachment unit of the blood pressure measurement device shown.

[0019] Figure 4 It shows Figure 1 a cross-sectional view showing an example of the state in which the attachment unit of the blood pressure measurement device shown is attached to the upper arm of the subject.

[0020] Figure 5 It shows Figure 1 a block diagram showing an example of the hardware configuration of the blood pressure measurement device shown.

[0021] Figure 6 It shows Figure 1 a block diagram showing an example of the software configuration of the blood pressure measurement device shown.

[0022] Figure 7 It shows Figure 6 a flowchart showing the first half of the processing procedure and processing content performed by the blood pressure measurement unit of the blood pressure measurement device shown.

[0023] Figure 8 It shows Figure 6 a flowchart showing the second half of the processing procedure and processing content performed by the blood pressure measurement unit of the blood pressure measurement device shown.

[0024] Figure 9 This is a waveform diagram for explaining the first operation example of the blood pressure measurement device according to the first embodiment of the present invention.

[0025] Figure 10 This is a waveform diagram for explaining the second operation example of the blood pressure measurement device according to the first embodiment of the present invention.

[0026] Figure 11 This is a waveform diagram for explaining the third operation example of the blood pressure measurement device according to the first embodiment of the present invention.

[0027] Figure 12 This is a waveform diagram for explaining the fourth operation example of the blood pressure measurement device according to the first embodiment of the present invention.

[0028] Figure 13It is a waveform diagram for explaining the fifth operation example of the blood pressure measurement device according to the first embodiment of the present invention.

[0029] Figure 14 It is a waveform diagram for explaining the sixth operation example of the blood pressure measurement device according to the first embodiment of the present invention.

[0030] Figure 15 It is a diagram showing an example of the configuration of the back side of the attachment unit of the blood pressure measurement device according to the second embodiment of the biological signal measurement device of the present invention.

[0031] Figure 16 It is a block diagram showing an example of the hardware configuration of the blood pressure measurement device according to the second embodiment of the present invention.

[0032] Figure 17 It is a block diagram showing an example of the software configuration of the blood pressure measurement device according to the second embodiment of the present invention.

[0033] Figure 18 It is shown by Figure 17 The flowchart of the first half of the processing procedure and processing content performed by the blood pressure measurement unit of the blood pressure measurement device.

[0034] Figure 19 It is shown by Figure 17 The flowchart of the second half of the processing procedure and processing content performed by the blood pressure measurement unit of the blood pressure measurement device.

[0035] Figure 20 It is a waveform diagram for explaining the first operation example of the blood pressure measurement device according to the second embodiment of the present invention.

[0036] Figure 21 It is a waveform diagram for explaining the second operation example of the blood pressure measurement device according to the second embodiment of the present invention.

[0037] Figure 22 It is a diagram showing an example of the configuration of the back side of the attachment unit of the blood pressure measurement device according to the third embodiment of the biological signal measurement device of the present invention.

[0038] Figure 23 It is a block diagram showing the hardware configuration of the blood pressure measurement device according to the third embodiment of the present invention.

[0039] Figure 24 It is a block diagram showing the software configuration of the blood pressure measurement device according to the third embodiment of the present invention.

[0040] Figure 25 It is shown by Figure 24Flowchart of the first half of the processing procedure and processing content performed by the blood pressure measurement unit of the blood pressure measurement device shown

[0041] Figure 26 It is shown by Figure 24 Flowchart of the second half of the processing procedure and processing content performed by the blood pressure measurement unit of the blood pressure measurement device shown

[0042] Figure 27 It is a waveform diagram for explaining an operation example of the blood pressure measurement device according to the third embodiment of the present invention Detailed implementation manners

[0043] Hereinafter, embodiments of one aspect of the present invention will be described based on the drawings. However, the embodiments described below are only examples of the present invention in all aspects

[0044] [First Embodiment]

[0045] (Constitution example)

[0046] (1) Overall constitution of the device

[0047] Figure 1 It is a diagram showing the overall constitution of the blood pressure measurement device as the first embodiment of the biological signal measurement device of the present invention. In addition Figure 5 and Figure 6 are respectively block diagrams showing Figure 1 the hardware constitution and software constitution of the blood pressure measurement device shown

[0048] The blood pressure measurement device of the first embodiment is composed of a mounting unit 10 and a blood pressure measurement unit 20 connected to the mounting unit 10. It should be noted that Figure 1 in the example, the mounting unit 10 and the blood pressure measurement unit 20 are shown as being separated, but it may also be configured as follows: the blood pressure measurement unit 20 is provided integrally with the mounting unit 10, whereby the blood pressure measurement device functions as a so-called wearable device

[0049] (2) Mounting unit 10

[0050] As Figure 1 exemplarily shown, the mounting unit 10 is mounted on the upper arm portion 1 of the subject Figure 2 and Figure 3 respectively show a constitution example of the front side of the mounting unit 10 and a constitution example of the back side of the mounting unit 10

[0051] The attachment unit 10 has, for example, a belt portion 11 made of a flexible resin or fiber, and an attachment unit circuit portion 12 is disposed on the surface side of the belt portion 11. The attachment unit circuit portion 12 includes an operation unit 13, a display unit 14, an ECG detection unit 32 of an electrocardiogram (ECG) sensor 30 described later, and a pulse drive unit 42 of a pulse wave sensor 40.

[0052] The operation unit 13 is constituted by, for example, a push-button switch and is used for inputting an instruction to start / end blood pressure measurement, an instruction to display or transmit the measured blood pressure data, and the like. The display unit 14 uses, for example, a liquid crystal or an organic EL (electroluminescence) as a display device and is used for displaying the measured blood pressure data and the like. It should be noted that the operation unit 13 and the display unit 14 may be constituted by a flat device in which a sheet for a touch panel is disposed on the display screen of the display unit.

[0053] On the other hand, as Figure 3 illustrated by way of example, an electrode group 31 of the ECG sensor 30 is disposed along the longitudinal dimension direction of the belt portion 11 on the back side of the belt portion 11. A plurality of (six in this example) electrodes 311 to 316 are arranged at equal intervals in the electrode group 31 and are in contact with the skin of the subject to detect an ECG signal. It should be noted that, as Figure 3 illustrated by way of example, the arrangement position of the electrode group 31 in the width direction of the belt portion 11 is set to the side closer to the shoulder of the subject. This is to enable the ECG sensor 30 to detect an ECG signal at a position as close as possible to the heart of the subject.

[0054] As Figure 5 illustrated by way of example, the ECG detection unit 32 of the ECG sensor 30 has a switch circuit 321, a subtraction circuit 322, and an AFE (analog front end) 323. The switch circuit 321 selects two of the above six electrodes 311 to 316 each time according to a switching control signal output from a control unit 21 of a blood pressure measurement unit 20 described later and connects them to the subtraction circuit 322. The subtraction circuit 322 is constituted by, for example, an instrumentation amplifier and outputs the potential difference between the signals output from the two electrodes selected by the switch circuit 321. The AFE 323 has, for example, a low-pass filter (LPF), an amplifier, and an analog-to-digital converter. Then, the potential difference signal output from the subtraction circuit 322 is passed through the LPF to remove unnecessary noise components, and after being amplified by the amplifier, it is converted into a digital signal by the analog-to-digital converter, and the converted digital signal is output as an ECG signal to the blood pressure measurement unit 20.

[0055] In addition, on the back side of the belt portion 11, a photoelectric sensor 41 of the pulse wave sensor 40 is disposed at a substantially central portion in the longitudinal direction and the width direction of the belt portion 11. The photoelectric sensor 41 includes an LED (Light Emitting Diode) 411 as a light emitting element and a PD (Photo Diode) 412 as a light receiving element. Then, the light generated from the LED 411 is irradiated onto the skin surface of the upper arm portion 1, and the reflected light generated from the skin surface of the irradiated light is received by the PD 412, and an electric signal corresponding to the received light intensity is output to the pulse driving unit 42.

[0056] The pulse driving unit 42 of the pulse wave sensor 40 has a power-on and voltage detection circuit 421. The power-on and voltage detection circuit 421 intermittently or continuously drives the LED 411 to emit light according to the light emission control signal output from the control unit 21 of the blood pressure measurement unit 20. The intermittent light emission control operation will be described in detail later. In addition, after removing the noise component from the electric signal output from the PD 412, the power-on and voltage detection circuit 421 converts it into a digital signal after amplifying it to a specified level, and outputs a pulse wave signal composed of the converted digital signal to the blood pressure measurement unit 20.

[0057] It should be noted that although not shown in the figure, a loop surface member and a hook surface member constituting a hook-and-loop fastener are respectively pasted on the front side and the back side of the belt portion 11. By using the above hook-and-loop fastener, the mounting unit 10 is fixed in a state where the belt portion 11 is wound around the circumference of the upper arm portion 1 of the subject. Figure 4 It is a cross-sectional view showing an example of the state where the mounting unit 10 is mounted on the upper arm portion 1.

[0058] (3) Blood pressure measurement unit

[0059] The blood pressure measurement unit 20 includes a control unit 21 having a hardware processor such as a Central Processing Unit (CPU). A program storage unit 22, a data storage unit 23, and a communication unit 24 are connected to the control unit 21. In addition, a power supply circuit 25 is built in the blood pressure measurement unit 20.

[0060] The communication unit 24 is used to send the measured blood pressure data to an information terminal (not shown) under the control of the control unit 21. As a communication interface, for example, an interface adopting a small power data communication standard such as Bluetooth (registered trademark) is used. In addition, as the information terminal, for example, a smart phone or a personal computer is used.

[0061] The power supply circuit 25 generates the required power supply voltage Vcc based on the output of the battery 251, and supplies the generated power supply voltage Vcc to each part in the blood pressure measurement unit 20 and the connection unit circuit part 12 of the connection unit 10 respectively.

[0062] In the program storage unit 22, for example, as a storage medium, a non-volatile memory such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that can be written and read at any time is combined with a non-volatile memory such as a ROM (Read Only Memory). The program storage unit 22 stores not only middleware such as an OS (Operating System), but also programs required to execute various control processes of an embodiment of the present invention.

[0063] The data storage unit 23 is, for example, a storage medium formed by combining a non-volatile memory such as an HDD or an SSD that can be written and read at any time with a volatile memory such as a RAM (Random Access Memory). It has an ECG signal storage unit 231, a pulse wave signal storage unit 232, and a blood pressure data storage unit 233 as the main storage areas for implementing the first embodiment of the present invention.

[0064] The ECG signal storage unit 231 is used to store the ECG signals output from the above-mentioned ECG sensor 30 in sequence. The pulse wave signal storage unit 232 is used to store the pulse wave signals output from the above-mentioned pulse wave sensor 40 in sequence. The blood pressure data storage unit 233 is used to store the blood pressure data of each heartbeat estimated in the control unit 21 described later.

[0065] The control unit 21 has an ECG signal acquisition unit 211, an ECG feature quantity detection unit 212, a pulse wave signal acquisition unit 213, a pulse wave feature quantity detection unit 214, a pulse wave conduction time calculation unit 215, a blood pressure estimation unit 216, a light emission control unit 217, and a blood pressure data output unit 218 in terms of the processing functions for implementing the first embodiment of the present invention. These processing units 211 to 218 are all realized by causing the hardware processor of the control unit 21 to execute the programs stored in the program storage unit 22.

[0066] The ECG signal acquisition unit 211 performs the following processing: It introduces the ECG signal output from the ECG detection unit 32 of the ECG sensor 30, and causes the ECG signal storage unit 231 to temporarily store the introduced ECG signal in time series. The ECG feature quantity detection unit 212 performs the following processing: It reads the ECG signal from the above-mentioned ECG signal storage unit 231, and detects the R-wave peak RP of each heartbeat, which is one of its feature quantities, from the ECG signal.

[0067] The pulse wave signal acquisition unit 213 performs the following processing: It introduces the pulse wave signal output from the pulse drive unit 42 of the pulse wave sensor 40, and causes the pulse wave signal storage unit 232 to temporarily store the pulse wave signal in time series. The pulse wave feature quantity detection unit 214 performs the following processing: It reads the pulse wave signal from the pulse wave signal storage unit 232, and detects the rising edge (pulse wave rising edge) PS of each heartbeat, which is one of its feature quantities, from the pulse wave signal.

[0068] The pulse wave conduction time calculation unit 215 performs the following processing: Based on the time difference between the R-wave peak RP detected by the above-mentioned ECG feature quantity detection unit 212 and the pulse wave rising edge PS detected by the above-mentioned pulse wave feature quantity detection unit 214, it calculates the pulse wave conduction time (PTT) of each heartbeat. The blood pressure estimation unit 216 performs the following processing: For example, it uses a conversion table representing the relationship between PTT and blood pressure values pre-stored in the data storage unit 23 or uses a conversion formula to estimate the blood pressure value corresponding to the calculated above-mentioned pulse wave conduction time (PTT).

[0069] The light emission control unit 217 supplies a light emission control signal for intermittently driving the light emission of the LED 411 of the pulse wave sensor 40 to the pulse drive unit 42, and has the following respective processing functions, for example.

[0070] (1) Before the start of the blood pressure measurement operation, it sets a preparation mode, and estimates the time correlation between the ECG signal and the pulse wave signal during a preset preparation period. For example, during multiple heartbeats included in the above-mentioned preparation period, the PTT is calculated respectively, and its average value is calculated. Then, based on the calculated average value of PTT, the light emission control mode that defines the light emission period and the light extinction period of the LED 411 is set. The light emission period is set to include at least a certain interval before and after the pulse wave rising edge PS of the pulse wave signal.

[0071] It should be noted that instead of the average value of PTT, the length of the light emission period can also be set based on the maximum value of PTT obtained during the above-mentioned preparation period. In this way, even if the heartbeat interval becomes longer due to some reason, the pulse wave rising edge PS of the pulse wave signal can be detected with a high probability.

[0072] (2) In the blood pressure measurement mode after the above preparation mode, every time the R-wave peak RP of the ECG signal is detected, a light emission control signal for intermittently driving the LED 411 of the pulse wave sensor 40 to emit light is generated in synchronization with the detection timing of the R-wave peak RP according to the light emission control mode set in the above preparation mode. Then, the generated light emission control signal is supplied to the pulse drive unit 42 of the pulse wave sensor 40.

[0073] The blood pressure data output unit 218 performs the following processing: When a display request for blood pressure data is input through the operation unit 13, the blood pressure data is read out from the blood pressure data storage unit 233, and the display unit 14 displays the blood pressure data. In addition, the blood pressure data output unit 218 performs the following processing: When a transmission request for blood pressure data is input through the operation unit 13, the blood pressure data is read out from the blood pressure data storage unit 233, and the blood pressure data is transmitted from the communication unit 24 to the information terminal preset as the transmission target.

[0074] (Operation example)

[0075] Next, the operation of the blood pressure measurement device configured as described above will be described. It should be noted that in this example, the case where the subject measures their own blood pressure changes during sleep, for example, is used for description.

[0076] Figure 7 and Figure 8 are flowcharts showing the processing procedures and processing contents performed by the control unit 21 of the blood pressure measurement unit 20.

[0077] (1) Preparation mode

[0078] The subject first wraps the belt portion 11 of the attachment unit 10 around their own upper arm portion 1 and fixes it with a hook-and-loop fastener in a state where the back side of the belt is in contact with the skin surface of the upper arm portion 1. Then, in this state, the operation unit 13 provided in the attachment unit 10 is operated to input a measurement start request. This measurement start request also serves as a power-on signal.

[0079] In step S10, the blood pressure measurement unit 20 monitors the input of the measurement start request. In this state, when the above measurement start request is input from the attachment unit 10, under the control of the control unit 21, the power supply circuit 25 operates, and starts supplying the power supply voltage Vcc to each part in the device. As a result, the blood pressure measurement unit 20 and the attachment unit 10 are in an operating state.

[0080] When in the operating state, under the control of the light emission control unit 217, the blood pressure measurement unit 20 first generates a continuous light emission control signal in step S11 and supplies the generated continuous light emission control signal to the pulse driving unit 42 of the pulse wave sensor 40. As a result, the LED 411 is continuously driven to emit light by the pulse driving unit 42, and thus the pulse wave signal detected by the pulse wave sensor 40 is continuously output.

[0081] In this state, in step S12, the blood pressure measurement unit 20 acquires the ECG signal output from the above-mentioned ECG sensor 30 through the ECG signal acquisition unit 211 and causes the ECG signal storage unit 231 to store the ECG signal in chronological order. In addition, in step S13, the blood pressure measurement unit 20 acquires the pulse wave signal output from the above-mentioned pulse wave sensor 40 through the pulse wave signal acquisition unit 213 and causes the pulse wave signal storage unit 232 to store the pulse wave signal in chronological order.

[0082] Then, in step S14, the blood pressure measurement unit 20 reads the ECG signal from the above-mentioned ECG signal storage unit 231 through the ECG feature quantity detection unit 212, detects the R-wave peak RP as one of its feature quantities, and reads the pulse wave signal from the above-mentioned pulse wave signal storage unit 232 through the pulse wave feature quantity detection unit 214, and detects the pulse wave rising edge PS as one of its feature quantities.

[0083] Next, in step S15, the blood pressure measurement unit 20 calculates the time difference between the detection timing of the above-mentioned R-wave peak RP detected within one heartbeat cycle and the detection timing of the above-mentioned pulse wave rising edge PS through the pulse wave conduction time calculation unit 215, and saves the calculated time difference as the pulse wave conduction time (PTT) within the above-mentioned one heartbeat cycle in the PTT data storage unit (not shown) in the data storage unit 23.

[0084] Then, in step S16, the blood pressure measurement unit 20 monitors whether a preset preparation period has elapsed. If not, it returns to step S11 and repeatedly executes the process of calculating the PTT for each heartbeat through steps S11 to S15. It should be noted that the above-mentioned preparation period is set as the average time required for the heartbeat to stabilize, for example, it is set as the time corresponding to 10 to 20 heartbeats. However, the length of the preparation period is not limited to this.

[0085] On the other hand, when the above-mentioned preparation period has elapsed, the blood pressure measurement unit 20 temporarily returns the LED 411 of the pulse wave sensor 40 from the continuous light emission state to the extinguished state. Then, in step S17, the light emission control unit 217 calculates, for example, the average value of each PTT for each heartbeat calculated during the above-mentioned preparation period, and sets a light emission control mode for intermittently driving the LED 411 of the pulse wave sensor 40 based on the calculated average value of the PTT, that is, sets the lengths of the light emission period and the extinguished period. It should be noted that a representative operation example of this light emission control mode will be described in detail later.

[0086] (2) Blood pressure measurement mode

[0087] When the setting of the above-mentioned light emission control mode in the preparation mode is completed, the blood pressure measurement unit 20 then starts the control operation of measuring the blood pressure for each heartbeat as follows.

[0088] That is, first in step S18, the blood pressure measurement unit 20 obtains the ECG signal output from the above-mentioned ECG sensor 30 through the ECG signal acquisition unit 211, and causes the ECG signal storage unit 231 to store the ECG signal in chronological order. Then, in step S19, the ECG feature quantity detection unit 212 reads the above-mentioned ECG signal from the above-mentioned ECG signal storage unit 231, detects the R-wave peak RP from the read above-mentioned ECG signal, and saves the detection timing in the ECG feature quantity storage unit (not shown) in the data storage unit 23.

[0089] Next, in step S20, under the control of the light emission control unit 217, the blood pressure measurement unit 20 generates a light emission control signal for starting the light emission of the LED 411 of the pulse wave sensor 40 in synchronization with the detection timing of the above-mentioned R-wave peak RP according to the light emission control mode set in the above-mentioned preparation mode, and provides it to the pulse drive unit 42 of the pulse wave sensor 40. As a result, the LED 411 of the pulse wave sensor 40 starts to emit light, and the pulse wave signal of the subject is output from the pulse wave sensor 40.

[0090] In step S21, the blood pressure measurement unit 20 obtains the pulse wave signal output from the above-mentioned pulse wave sensor 40 through the pulse wave signal acquisition unit 213, and causes the pulse wave signal storage unit 232 to store the pulse wave signal in chronological order. Then, in step S22, the pulse wave feature quantity detection unit 214 reads the above-mentioned pulse wave signal from the above-mentioned pulse wave signal storage unit 232, and detects the pulse wave rising edge PS from the pulse wave signal. Then, when the pulse wave rising edge PS is detected, the detection timing is saved in the pulse wave feature quantity storage unit (omitted from illustration) in the data storage unit 23.

[0091] In addition, under the control of the light emission control unit 217, the blood pressure measurement unit 20 monitors the end timing of the light emission period specified by the above light emission control mode in step S23. Then, when the light emission period ends, the light emission of the LED 411 of the pulse wave sensor 40 is stopped in step S24.

[0092] When the blood pressure measurement unit 20 detects the above-mentioned pulse wave rising edge PS, in step S25, the pulse wave conduction time calculation unit 215 calculates the time difference between the detection timing of the R wave peak RP of the ECG signal detected previously in step S19 and the detection timing of the pulse wave rising edge PS of the above-mentioned pulse wave signal detected in step S22 as the PTT of the current heartbeat. Then, in step S26, the blood pressure estimation unit 216 estimates the blood pressure value based on the calculated PTT, and causes the blood pressure data storage unit 233 to store the estimated blood pressure value in association with the detection timing of the above-mentioned R wave peak RP, that is, the identification information of the heartbeat. As a result, the blood pressure data storage unit 233 stores the blood pressure value of one heartbeat of the subject.

[0093] While executing the process for the above-mentioned blood pressure measurement, the blood pressure measurement unit 20 monitors the input of the display / sending request of the blood pressure data in step S27 through the blood pressure data output unit 218. Then, for example, when the subject performs an operation for the display / sending request through the operation unit 13, under the control of the blood pressure data output unit 218, the blood pressure data is read out from the blood pressure data storage unit 233 in step S28 and the display unit 14 displays the blood pressure data, or the blood pressure data is sent from the communication unit 24 to the information terminal.

[0094] In addition, while executing the process for the above-mentioned blood pressure measurement, the blood pressure measurement unit 20 monitors the input of the measurement end request in step S29. In this state, for example, when the subject performs an operation requesting the end of the measurement through the operation unit 13, the blood pressure measurement unit 20 ends the process for blood pressure measurement and stops supplying the power supply voltage Vcc from the power supply circuit 25 to each unit.

[0095] It should be noted that after the power supply is ended, the blood pressure data stored in the blood pressure data storage unit 233 is also retained. In addition, for example, it is preferable to save the light emission control mode set by the light emission control unit 217 in association with the identification information of the subject in the data storage unit 23. In this way, when measuring the blood pressure of the same subject next time, the blood pressure measurement can be immediately started based on the light emission control mode corresponding to the subject.

[0096] (Representative operation example)

[0097] Next, a representative operation example in the first embodiment will be described. It should be noted that the operation example is not limited to the following examples, and various other operation examples can be considered.

[0098] (1) First operation example

[0099] Figure 9 It is a signal waveform diagram for explaining the first operation example.

[0100] First, during the preparation period, the blood pressure measurement unit 20 sets the light emission period to a period T1 that is longer than the average value of PTT by a predetermined time based on the average value of PTT, which is the time difference between the R-wave peak RP of the ECG signal calculated for each heartbeat and the pulse wave rising edge PS of the pulse wave signal, and sets the extinguishing period to a period T2 until the R-wave peak RP of the ECG signal of the next heartbeat is detected.

[0101] In the blood pressure measurement mode, when the blood pressure measurement unit 20 detects the R-wave peak RP of the ECG signal, it starts the light emission of the LED 411 of the pulse wave sensor 40 at the detection timing of the R-wave peak RP. Then, the pulse wave sensor 40 operates and a pulse wave signal is output. The blood pressure measurement unit 20 detects the pulse wave rising edge PS from the output pulse wave signal. Then, the time difference between the detection timing of the R-wave peak RP of the ECG signal and the detection timing of the pulse wave rising edge PS of the pulse wave signal is calculated as PTT in one heartbeat, and the blood pressure value is estimated based on this PTT.

[0102] In addition, when the length of the light emission period reaches the set value T1 of the light emission period set in the preparation mode during the light emission operation of the LED 411 of the pulse wave sensor 40, the blood pressure measurement unit 20 turns off the LED 411. Then, this extinguished state is maintained until the R-wave peak RP of the ECG signal of the next heartbeat is detected. After that, the blood pressure measurement unit 20 repeatedly performs the following process: whenever the R-wave peak RP of the ECG signal is detected, the LED 411 of the pulse wave sensor 40 is intermittently turned on synchronously with the detection timing of the R-wave peak RP, and the blood pressure value of each heartbeat is measured.

[0103] According to the first operation example, the LED 411 of the pulse wave sensor 40 emits light only for the light emission period T1 set during the preparation period synchronously with the R-wave peak RP of the ECG signal for each heartbeat. Therefore, compared with the case where the LED 411 of the pulse wave sensor 40 is always on, the power consumption caused by the LED 411 of the pulse wave sensor 40 can be reduced, and thus the blood pressure can be continuously measured throughout the sleep period even without using a large-capacity battery 251.

[0104] Also, according to the first operation example, the light emission period T1 of the LED 411 is set to a value that starts from the detection timing of the R-wave peak RP and is longer than the PTT value by a specified length. Therefore, the pulse wave rising edge PS of the pulse wave signal can be reliably detected without omission. Thus, the blood pressure can be measured for each heartbeat without data loss.

[0105] (2) Second operation example

[0106] Figure 10 is a signal waveform diagram for explaining the second operation example.

[0107] In this example, the blood pressure measurement unit 20 sets the length of the light emission period to T1 in the same way as in the Figure 9 first operation example shown, and intermittently sets an extinguishing period during this light emission period T1. The duty ratio, which is the time ratio of light emission to extinguishing in the light emission period T1, is set to 50% for example, but can be any value as long as it is in the range of less than 100% and more than 0%.

[0108] According to the second operation example, within the period T1 set for detecting the pulse wave rising edge PS of the pulse wave signal, the LED 411 further performs an intermittent light emission operation, whereby the cumulative light emission period of the LED 411 is further shortened. As a result, the power consumption of the battery 251 is further suppressed, and the time for continuously measuring blood pressure can be further extended.

[0109] (3) Third operation example

[0110] Figure 11 is a signal waveform diagram for explaining the third operation example.

[0111] In this example, the blood pressure measurement unit 20 sets the length of the light emission period to T1 in the same way as in the Figure 9 first operation example shown, and sets an extinguishing period during this light emission period T1. Moreover, an intermittent light emission period is set during the extinguishing period T2 other than the above light emission period T1. The duty ratio, which is the time ratio of the light emission period to the extinguishing period in the extinguishing period T2, is set to 25% for example, but can be any value as long as it is in the range of less than 100% and more than 0%.

[0112] According to the third operation example, by setting an extinguishing period within the light emission period T1, the power consumption of the battery 251 can be further suppressed compared to the first operation example. In addition, by intermittently setting a light emission period during the extinguishing period T2, the pulse wave signal can be intermittently detected during the extinguishing period T2 as shown in Figure 11 so that, for example, even if the heartbeat cycle changes temporarily and the timing of the pulse wave rising edge PS shifts, the probability of detecting the pulse wave rising edge PS can be increased.

[0113] (4) Fourth operation example

[0114] Figure 12 It is a signal waveform diagram for explaining the fourth operation example.

[0115] In this example, the blood pressure measurement unit 20 starts from the detection timing of the R-wave peak RP of the ECG signal, first sets a waiting period T3, and after passing through this waiting period T3, then sets a light-emitting period T4.

[0116] The above-mentioned waiting period T3 and light-emitting period T4 are set as follows, for example. That is, in the preparation mode, the blood pressure measurement unit 20 obtains the average value or minimum value of the PTT, and also obtains the average value or maximum value of the offset amplitude of the detection timing of the rising edge PS of the pulse wave. Then, based on the above-mentioned respective obtained values, the waiting period T3 and the light-emitting period T4 are set. For example, regarding the waiting period T3, it is set such that even if the timing of the rising edge PS of the pulse wave becomes earlier, this timing will not be included in the waiting period T3. In addition, regarding the light-emitting period T4, it is set such that even if the timing of the rising edge PS of the pulse wave changes, this rising edge PS of the pulse wave will be included in the light-emitting period T4.

[0117] According to the fourth operation example, for each heartbeat, starting from the detection timing of the R-wave peak RP of the ECG signal, the waiting period T3 is set, and after passing through this waiting period T3, then the light-emitting period T4 is set. Therefore, it is possible to limit the light-emitting operation of the LED 411 of the pulse wave sensor 40 during the period when the rising edge PS of the pulse wave signal is predicted to be detected, and thus it is possible to further shorten the light-emitting period of the LED 411 for each heartbeat. As a result, it is possible to further suppress the power consumption of the battery and extend the continuous blood pressure measurement time.

[0118] (5) Fifth operation example

[0119] Figure 13 It is a signal waveform diagram for explaining the fifth operation example.

[0120] This fifth operation example is an operation example that further improves the above-mentioned fourth operation example, and synchronizes the end timing of the light-emitting period for each heartbeat with the detection timing of the rising edge PS of the pulse wave.

[0121] That is, for each heartbeat, the blood pressure measurement unit 20 starts from the detection timing of the R-wave peak RP of the ECG signal, first sets a waiting period T3. Then, after passing through this waiting period T3, it starts to emit light next, and then ends the above-mentioned light emission at the time point when the rising edge PS of the pulse wave signal of the heartbeat is detected.

[0122] According to the fifth operation example, for each heartbeat, the light emission period T5 of the LED 411 ends at the time point of the pulse wave rising edge PS of the detected pulse wave signal. Therefore, compared with the case of the above-described fourth operation example, the light emission operation time of the LED 411 of the pulse wave sensor can be further shortened, whereby the power consumption of the battery 251 can be further suppressed and the continuous blood pressure measurement time can be extended.

[0123] (6) Sixth operation example

[0124] Figure 14 It is a signal waveform diagram for explaining the sixth operation example.

[0125] The sixth operation example is an operation example obtained by further improving the above-described fourth operation example. That is, when the blood pressure measurement unit 20 sets a waiting period synchronously with the detection timing of the R wave peak RP of the ECG signal, the waiting period is extended by an amount of one heartbeat cycle and set as T6, and after passing through the waiting period T6, a light emission period T7 is set next.

[0126] According to the sixth operation example, when performing light emission control synchronously with the detection timing of the R wave peak RP of the ECG signal, the start timing of the light emission period T7 can be delayed by one heartbeat cycle. As a result, even when the processing speed of the control unit 21 is slow or the processing load is large and processing delay is likely to occur, light emission control can be accurately performed without delay.

[0127] It should be noted that in this sixth operation example, the light emission period T7 may also end at the time point of the pulse wave rising edge PS of the detected pulse wave signal of the next heartbeat.

[0128] (Effect)

[0129] As described in detail above, in the first embodiment of the present invention, the LED 411 of the pulse wave sensor 40 intermittently emits light, and the light emission control mode of the intermittent light emission operation is synchronized with the detection timing of the R wave peak RP of the ECG signal for each heartbeat, and the light emission control mode is set according to the PTT indicating the time correlation between the ECG signal and the pulse wave signal.

[0130] Therefore, it is possible to reduce the power consumption caused by the LED 41 of the pulse wave sensor 40, suppress the power consumption of the battery 251, and thus continuously measure the blood pressure of the subject at each heartbeat during the entire sleep period even without using a large-capacity battery. In addition, since the light emission period of the LED 411 of the pulse wave sensor 40 is set based on the PTT calculated from the ECG signal obtained by the ECG sensor 30 and the pulse wave signal obtained by the pulse wave sensor 40, it is possible to reliably detect the pulse wave rising edge PS of the pulse wave signal without omission, and thus reliably measure the blood pressure at each heartbeat without missing data.

[0131] [Second Embodiment]

[0132] (Configuration Example)

[0133] Figure 15 FIG. is a diagram showing the configuration of the back side of the mounting unit 10 used in the blood pressure measurement device according to the second embodiment of the present invention. In addition, Figure 16 and Figure 17 are block diagrams showing the hardware configuration and software configuration of the blood pressure measurement device, respectively. It should be noted that in Figure 15 、 Figure 16 and Figure 17 ,the same parts as those in Figure 3 、 Figure 5 and Figure 6 are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0134] (1) Mounting Unit

[0135] On the back side of the belt portion 11 of the mounting unit 10, a photoelectric sensor 51 of the first pulse wave sensor 50 and a photoelectric sensor 41 of the second pulse wave sensor 40 are respectively arranged at a predetermined distance in the width direction of the belt portion 11. The arrangement relationship of these photoelectric sensors 41 and 51 is set such that the photoelectric sensor 51 of the first pulse wave sensor 50 is arranged on the side closer to the heart of the subject, and the photoelectric sensor 41 of the second pulse wave sensor 40 is arranged on the side farther from the heart of the subject. Each of the photoelectric sensors 41 and 51 includes an LED 411 and 511 as a light emitting element and a PD 412 and 512 as a light receiving element.

[0136] The second pulse wave sensor 40 corresponds to the pulse wave sensor 40 described in the first embodiment, and the photoelectric sensor 41 includes an LED 411 as a light emitting element and a PD 412 as a light receiving element. In addition, the pulse driving unit 42 intermittently drives the LED 411 to emit light according to the light emission control signal output from the control unit 21 of the blood pressure measurement unit 20.

[0137] On the other hand, the first pulse wave sensor 50 replaces the ECG sensor 30 described in the first embodiment. The photoelectric sensor 51 includes an LED 511 as a light emitting element and a PD 512 as a light receiving element. In addition, the pulse driving unit 52 continuously drives the LED 511 to emit light through the power supply and voltage detection circuit 521. However, when a light emission control signal instructing intermittent light emission is sent from the control unit 21, the pulse driving unit 52 intermittently drives the LED 511 to emit light according to the light emission control signal.

[0138] Similar to the power supply and voltage detection circuit 421 of the second pulse wave sensor 40, the power supply and voltage detection circuit 521 of the first pulse wave sensor 50 removes the noise component from the electrical signal output by the PD 512, amplifies it to a specified level, and then converts it into a digital signal, and outputs a pulse wave signal composed of the converted digital signal to the blood pressure measurement unit 20.

[0139] (2) Blood pressure measurement unit

[0140] In the data storage unit 23, for implementing the second embodiment of the present invention, there are provided a first pulse wave signal storage unit 234, a second pulse wave signal storage unit 232, and a blood pressure data storage unit 233. The first pulse wave signal storage unit 234 is used to store the first pulse wave signal output from the first pulse wave sensor 50. The second pulse wave signal storage unit 232 corresponds to the pulse wave signal storage unit 232 described in the first embodiment and is used to store the second pulse wave signal output from the second pulse wave sensor 40. The blood pressure data storage unit 233 is used to store the blood pressure data of each heartbeat estimated in the control unit 21.

[0141] The control unit 21 has a first pulse wave signal acquisition unit 221 and a first pulse wave feature quantity detection unit 222 in place of the processing functions of the ECG signal acquisition unit 211 and the ECG feature quantity detection unit 212 described in the first embodiment. These processing units 221 and 222 are also implemented by causing the hardware processor of the control unit 21 to execute the programs stored in the program storage unit 22, similar to the other processing units 213 to 218.

[0142] The first pulse wave signal acquisition unit 221 performs the following processing: introducing the first pulse wave signal output from the pulse driving unit 52 of the first pulse wave sensor 50, and causing the first pulse wave signal storage unit 234 to store the first pulse wave signal in time sequence. The first pulse wave feature quantity detection unit 222 performs the following processing: reading the first pulse wave signal from the first pulse wave signal storage unit 234, and detecting the pulse wave rising edge PS1 of each heartbeat as one of its feature quantities from the first pulse wave signal.

[0143] The pulse wave signal acquisition unit (herein, referred to as the second pulse wave signal acquisition unit for distinction from the first pulse wave signal acquisition unit) 213 performs the following processes: It introduces the pulse wave signal (similarly referred to as the second pulse wave signal) output from the pulse driving unit 42 of the pulse wave sensor (similarly referred to as the second pulse wave sensor) 40, and causes the pulse wave signal storage unit (similarly referred to as the second pulse wave signal storage unit) 232 to store the second pulse wave signal in sequence. The pulse wave feature quantity detection unit (similarly referred to as the second pulse wave feature quantity detection unit) 214 performs the following processes: It reads the second pulse wave signal from the second pulse wave signal storage unit 232, and detects the pulse wave rising edge PS2 of each heartbeat, which is one of its feature quantities, from the second pulse wave signal.

[0144] The pulse wave conduction time calculation unit 215 performs the following processes: Based on the time difference between the first pulse wave rising edge PS1 detected by the first pulse wave feature quantity detection unit 222 and the second pulse wave rising edge PS2 detected by the second pulse wave feature quantity detection unit 214, it calculates the pulse wave conduction time (PTT) of each heartbeat.

[0145] The blood pressure estimation unit 216 performs the following processes in the same manner as in the first embodiment: It uses a conversion table representing the relationship between PTT and blood pressure values or uses a conversion formula to obtain the blood pressure value corresponding to the calculated pulse wave conduction time (PTT).

[0146] The light emission control unit 227 provides a light emission control signal for intermittently driving the light emission of the LED 411 of the second pulse wave sensor 40 to the pulse driving unit 42, and has, for example, the following respective processing functions.

[0147] (1) Before the start of the blood pressure measurement operation, it sets a preparation mode, and estimates the time correlation between the first pulse wave signal and the second pulse wave signal during a preset preparation period. For example, during the multiple heartbeats detected within the above preparation period, the PTT is calculated respectively, and its average value is calculated. Then, based on the calculated average value of PTT, the light emission control mode that defines the light emission period and the extinguishing period of the LED 411 is set. The light emission period is set to include at least a certain interval before and after the pulse wave rising edge PS2 of the second pulse wave signal.

[0148] It should be noted that instead of the average value of PTT, the length of the light emission period can also be set based on the maximum value of PTT obtained within the above preparation period. In this way, even if the heart rate interval becomes longer due to some reason, the pulse wave rising edge PS of the pulse wave signal can be detected with a high probability.

[0149] (2) In the blood pressure measurement mode after the above preparation mode ends, whenever the pulse wave rising edge PS1 of the first pulse wave signal is detected, a light emission control signal for intermittently driving the light emission of LED411 is generated in synchronization with the detection timing of the pulse wave rising edge PS1 according to the light emission control mode set in the above preparation mode. Then, the generated light emission control signal is provided to the pulse driving unit 42 of the second pulse wave sensor 40.

[0150] (3) When intermittently driving the light emission of the LED511 of the first pulse wave sensor 50, a light emission control mode opposite to that of the LED411 of the second pulse wave sensor 40 is set, and a light emission control signal corresponding to the set light emission control mode is provided to the pulse driving unit 52 of the first pulse wave sensor 50.

[0151] (Operation example)

[0152] Next, the operation of the blood pressure measurement device configured as described above will be described.

[0153] Figure 18 And Figure 19 are flowcharts showing the processing procedures and processing contents performed by the control unit 21 of the blood pressure measurement unit 20. It should be noted that in Figure 18 and Figure 19 , for the steps with the same processing contents as those in the above Figure 7 and Figure 8 , the same symbols are used for description.

[0154] (1) Preparation mode

[0155] When the subject operates the operation unit 13 to input a measurement start request after attaching the attachment unit 10 to his / her upper arm 1, in the blood pressure measurement unit 20, through step S10, the above measurement start request is detected. As a result, the power supply voltage Vcc is supplied from the power supply circuit 25 to each part inside the device, and the blood pressure measurement unit 20 and the attachment unit 10 are in an operating state.

[0156] When in the operating state, under the control of the light emission control unit 227 of the blood pressure measurement unit 20, first, a continuous light emission control signal is generated in step S111, and the generated continuous light emission control signal is provided to the pulse driving units 52 and 42 of the first pulse wave sensor 50 and the second pulse wave sensor 40, respectively. As a result, the LED511 and 411 are continuously driven to emit light by the pulse driving units 52 and 42, and thus the first pulse wave signal and the second pulse wave signal are continuously output from the first pulse wave sensor 50 and the second pulse wave sensor 40, respectively.

[0157] In this state, in step S121, the blood pressure measurement unit 20 obtains the first pulse wave signal output from the first pulse wave sensor 50 through the first pulse wave signal acquisition unit 221, and temporarily stores the first pulse wave signal in the first pulse wave signal storage unit 234. In addition, in step S13, the blood pressure measurement unit 20 obtains the second pulse wave signal output from the second pulse wave sensor 40 through the second pulse wave signal acquisition unit 213, and temporarily stores the second pulse wave signal in the second pulse wave signal storage unit 232.

[0158] Then, in step S141, the blood pressure measurement unit 20 reads the first pulse wave signal from the first pulse wave signal storage unit 234 through the first pulse wave feature quantity detection unit 222, and detects its pulse wave rising edge PS1. At the same time, through the second pulse wave feature quantity detection unit 214, the second pulse wave signal is read from the second pulse wave signal storage unit 232, and its pulse wave rising edge PS2 is detected.

[0159] Next, in step S15, the blood pressure measurement unit 20 calculates the time difference between the detection timing of the pulse wave rising edge PS1 of the detected first pulse wave signal and the detection timing of the pulse wave rising edge PS2 of the second pulse wave signal through the pulse wave conduction time calculation unit 215, and temporarily stores the calculated time difference as the pulse wave conduction time (PTT) in the current heartbeat in the data storage unit 23.

[0160] Then, in step S16, the blood pressure measurement unit 20 monitors whether a preset preparation period has elapsed. If not, it returns to step S111 and repeatedly executes the process of calculating the PTT for each heartbeat. It should be noted that the above preparation period is set as the average time required for the heartbeat to stabilize, for example, it is set as the time corresponding to 10 to 20 heartbeats. However, the length of the preparation period is not limited to this.

[0161] On the other hand, when the above preparation period has elapsed, the blood pressure measurement unit 20 temporarily returns the LED 411 of the second pulse wave sensor 40 from the continuous lighting state to the extinguished state. Then, in step S17, through the lighting control unit 227, for example, the average value of each PTT calculated during the above preparation period is calculated, and based on the calculated average value of the PTT, a lighting control mode for intermittently driving the LED 411 of the second pulse wave sensor 40 to emit light is set, that is, the lengths of the lighting period and the extinguished period are set.

[0162] (2) Blood pressure measurement mode

[0163] When the setting of the above lighting control mode in the preparation mode is completed, the blood pressure measurement unit 20 then starts the control operation of measuring the blood pressure for each heartbeat as follows.

[0164] That is, first in step S181, the blood pressure measurement unit 20 acquires the first pulse wave signal output from the first pulse wave sensor 50 through the first pulse wave signal acquisition unit 221, and temporarily stores the first pulse wave signal in the first pulse wave signal storage unit 234. It should be noted that at this time, the LED 511 of the first pulse wave sensor 50 continuously performs a lighting operation, so the first pulse wave signal is continuously acquired.

[0165] Next, in step S191, the blood pressure measurement unit 20 reads the first pulse wave signal from the first pulse wave signal storage unit 234 through the first pulse wave feature quantity detection unit 222, detects the pulse wave rising edge PS1 from the read first pulse wave signal, and saves the detection timing in the data storage unit 23.

[0166] Then, in step S20, under the control of the light emission control unit 227, the blood pressure measurement unit 20 generates a light emission control signal for starting the light emission of the LED 411 of the second pulse wave sensor 40 in synchronization with the detection timing of the pulse wave rising edge PS1 according to the light emission control mode set in the above preparation mode, and supplies it to the pulse drive unit 42 of the second pulse wave sensor 40. As a result, the LED 411 of the second pulse wave sensor 40 starts to emit light, and the second pulse wave signal of the subject is output from the second pulse wave sensor 40.

[0167] In step S21, the blood pressure measurement unit 20 acquires the second pulse wave signal output from the second pulse wave sensor 40 through the second pulse wave signal acquisition unit 213, and temporarily stores the second pulse wave signal in the second pulse wave signal storage unit 232. Next, in step S22, the second pulse wave feature quantity detection unit 214 reads the second pulse wave signal from the second pulse wave signal storage unit 232, and detects the pulse wave rising edge PS2 from the second pulse wave signal. Then, when the pulse wave rising edge PS2 is detected, the detection timing is saved in the data storage unit 23.

[0168] In addition, under the control of the light emission control unit 227, the blood pressure measurement unit 20 monitors the end timing of the light emission period specified by the above light emission control mode in step S23. Then, when the light emission period ends, in step S24, the light emission of the LED 411 of the second pulse wave sensor 40 is stopped. It should be noted that the light emission operation of the LED 511 of the first pulse wave sensor 50 is maintained.

[0169] When the above-mentioned second pulse wave rising edge PS2 is detected, in step S25, the blood pressure measurement unit 20 calculates, as the PTT of the current heartbeat, the time difference between the detection timing of the pulse wave rising edge PS1 of the first pulse wave signal detected previously in step S191 and the detection timing of the pulse wave rising edge PS2 of the second pulse wave signal detected in the above step S22 through the pulse wave conduction time calculation unit 215. Then, in step S26, the blood pressure measurement unit 20 estimates the blood pressure value based on the calculated PTT through the blood pressure estimation unit 216, and causes the blood pressure data storage unit 233 to store the estimated blood pressure value. As a result, the blood pressure data storage unit 233 stores the blood pressure value of one heartbeat of the subject. It should be noted that the detection time may also be associated with the blood pressure value.

[0170] While executing the process for the above-mentioned blood pressure measurement, the blood pressure measurement unit 20 monitors the input of a display / transmission request for blood pressure data through the blood pressure data output unit 218 in step S27. Then, for example, when the subject performs an operation for the display / transmission request through the operation unit 13, under the control of the blood pressure data output unit 218, in step S28, the blood pressure data is read out from the blood pressure data storage unit 233 and the display unit 14 displays the blood pressure data, or the blood pressure data is transmitted from the communication unit 24 to the information terminal.

[0171] In addition, while executing the process for the above-mentioned blood pressure measurement, the blood pressure measurement unit 20 monitors the input of a measurement end request in step S29. In this state, for example, when the subject performs an operation requesting the end of measurement through the operation unit 13, the blood pressure measurement unit 20 ends the process for blood pressure measurement and stops supplying the power voltage Vcc from the power supply circuit 25 to each unit.

[0172] It should be noted that after the power supply is ended, the blood pressure data stored in the blood pressure data storage unit 233 is also retained. In addition, for example, it is preferable to save the light emission control mode set by the light emission control unit 227 in association with the identification information of the subject in the data storage unit 23. In this way, when measuring the blood pressure of the same subject next time, the blood pressure measurement can be immediately started based on the light emission control mode corresponding to the subject.

[0173] (Representative operation example)

[0174] Next, a representative operation example in the second embodiment will be described. It should be noted that the operation example is not limited to the following examples, and various other operation examples can be considered.

[0175] (1) First operation example

[0176] Figure 20It is a signal waveform diagram for explaining the first operation example.

[0177] During the preparation period, the blood pressure measurement unit 20 detects the pulse wave rising edge PS1 of the first pulse wave signal and the pulse wave rising edge PS2 of the second pulse wave signal for each heartbeat, and calculates the PTT representing the time difference between the detected pulse wave rising edges PS1 and PS2. Then, the average value of the PTTs of multiple heartbeats during the preparation period is calculated, and based on the calculated average value of the PTT, the light emission period is set to a period T8 that is longer than the average value of the PTT by a specified time. After that, the period until the pulse wave rising edge PS1 of the first pulse wave signal generated by the next heartbeat is detected is set as the extinguished period T9.

[0178] In the blood pressure measurement mode, when the blood pressure measurement unit 20 detects the pulse wave rising edge PS1 of the first pulse wave signal, it starts the light emission operation of the LED 411 of the second pulse wave sensor 40 at the detection timing of the pulse wave rising edge PS1. Then, the second pulse wave sensor 40 operates and the second pulse wave signal is output. The blood pressure measurement unit 20 detects the pulse wave rising edge PS2 from the output second pulse wave signal. Then, the time difference between the detection timing of the pulse wave rising edge PS1 of the first pulse wave signal and the detection timing of the pulse wave rising edge PS2 of the second pulse wave signal is calculated as the PTT in the current heartbeat, and the blood pressure value is estimated based on this PTT.

[0179] In addition, when the length of the light emission period reaches the set value T8 of the light emission period set in the above preparation mode during the light emission operation of the LED 411 of the second pulse wave sensor 40, the blood pressure measurement unit 20 turns off the LED 411. Then, this extinguished state is maintained until the pulse wave rising edge PS1 of the first pulse wave signal of the next heartbeat is detected. After that, the blood pressure measurement unit 20 repeatedly performs the following process: whenever the pulse wave rising edge PS1 of the first pulse wave signal is detected, the LED 411 of the second pulse wave sensor 40 is intermittently made to perform the light emission operation synchronously with the detection timing of the pulse wave rising edge PS1 to measure the blood pressure.

[0180] According to the first operation example, the LED 411 of the second pulse wave sensor 40 performs the light emission operation only for the light emission period T8 in synchronization with the pulse wave rising edge PS1 of the first pulse wave signal for each heartbeat. Therefore, compared with the case where the LED 411 of the second pulse wave sensor 40 is always lit, the power consumption caused by the LED 411 can be reduced, so that the blood pressure can be continuously measured throughout the sleep period even without using a large-capacity battery 251.

[0181] In addition, according to the first operation example, the light emission period T8 of the LED 411 of the second pulse wave sensor 40 is set to a value that starts from the detection timing of the pulse wave rising edge PS1 of the first pulse wave signal and is longer than the PTT value by a specified length. Therefore, the pulse wave rising edge PS2 of the second pulse wave signal can be reliably detected. As a result, the blood pressure value for each heartbeat can be measured without omission in a manner that does not cause data omission.

[0182] (2) Second operation example

[0183] Figure 21 is a signal waveform diagram for explaining the second operation example.

[0184] In this example, the blood pressure measurement unit 20 sets the light emission control mode of the LED 411 of the second pulse wave sensor 40 in the light emission control unit 227 in the same manner as the first operation example shown in Figure 20 with a light emission period of T8 and an extinction period of T9. In addition, at the same time, the light emission control mode of the LED 511 of the first pulse wave sensor 50 is set in a manner opposite to the light emission control mode of the LED 411 of the second pulse wave sensor 40, that is, with a light emission period of T9 and an extinction period of T8.

[0185] According to the second operation example, the LED 411 of the second pulse wave sensor 40 performs an intermittent light emission operation synchronously with the pulse wave rising edge PS1 of the first pulse wave signal in the same manner as the first operation example, and the LED 511 of the first pulse wave sensor 50 performs an intermittent light emission operation in a light emission mode opposite to the intermittent light emission operation of the LED 411 of the second pulse wave sensor 40. Therefore, although two sets of pulse wave sensors 40 and 50 are used, the power consumed for the light emission operation of the LEDs of the pulse wave sensors is the amount of one pulse wave sensor. Therefore, the power consumption of the battery 251 can be suppressed, and the blood pressure measurement for each heartbeat can be performed for a long time even without using a large-capacity battery.

[0186] It should be noted that in the second embodiment, for example, an extinction period can be partially set within the light emission period T8 as illustrated in Figure 10 , and in addition, a light emission period can be intermittently set within the above-mentioned extinction period T9 as illustrated in Figure 11 . Moreover, the light emission period can be set after a waiting period as illustrated in Figure 12 or Figure 14 , and in addition, the end timing of the light emission period can be set synchronously with the detection timing of the pulse wave rising edge PS2 of the second pulse wave signal as illustrated in Figure 13 .

[0187] (Effect)

[0188] As described above, according to the second embodiment, in the apparatus for measuring blood pressure based on the PTT method using two sets of pulse wave sensors 40 and 50, the LED 411 of the second pulse wave sensor 40 is intermittently driven to emit light synchronously with the pulse wave rising edge PS1 of the first pulse wave signal output from the first pulse wave sensor 50. As a result, the power consumption caused by the LED 411 of the second pulse wave sensor 40 is suppressed, and thus blood pressure can be measured for each heartbeat over a long period of time even without using a large-capacity battery.

[0189] In addition, since the light emission period of the LED 411 of the second pulse wave sensor 40 is set based on the PTT calculated from the first pulse wave signal obtained by the first pulse wave sensor 50 and the second pulse wave signal obtained by the second pulse wave sensor 40, the pulse wave rising edge of the second pulse wave signal can be reliably detected without omission, and thus blood pressure can be reliably measured for each heartbeat without missing data.

[0190] [Third Embodiment]

[0191] (Configuration Example)

[0192] Figure 22 FIG. is a diagram showing the configuration of the back side of the mounting unit 10 used in the blood pressure measuring apparatus according to the third embodiment of the present invention. In addition, Figure 23 and Figure 24 are respectively block diagrams showing the hardware configuration and software configuration of the blood pressure measuring apparatus. It should be noted that in Figure 22 , Figure 23 and Figure 24 , the same parts as Figure 3 , Figure 5 and Figure 6 are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0193] (1) Mounting Unit

[0194] On the back side of the belt portion 11 of the mounting unit 10, at a substantially central portion in the longitudinal direction of the belt portion 11, a piezoelectric sensor 61 of the heart sound sensor 60 and a photoelectric sensor 41 of the pulse wave sensor 40 are respectively arranged at a predetermined distance in the width direction of the belt portion 11. The arrangement relationship between the piezoelectric sensor 61 and the photoelectric sensor 41 is set such that the piezoelectric sensor 61 of the heart sound sensor 60 is arranged on the side closer to the heart of the subject, and the photoelectric sensor 41 of the pulse wave sensor 40 is arranged on the side farther from the heart of the subject.

[0195] The piezoelectric sensor 61 of the heart sound sensor 60 detects, for example, the pressure change in the space generated by the heart sound through a piezoelectric element, converts the pressure change into an electrical signal, and outputs it.

[0196] In addition, the heart sound sensor 60 includes a heart sound detection circuit 62. The heart sound detection circuit 62 has a heart sound band detection unit 621 and an analog-to-digital converter (A / D) 622. The heart sound band detection unit 621 passes an electrical signal representing the pressure change output from the piezoelectric sensor 61 through, for example, an LPF or a BPF (band pass filter), thereby allowing the frequency components including the heart sound to pass through, and outputs the passed frequency components as heart sound signals. The A / D 622 converts the heart sound signals output from the heart sound band detection unit 621 into digital signals and outputs them to the blood pressure measurement unit 20.

[0197] (2) Blood pressure measurement unit

[0198] In the data storage unit 23, in order to implement the third embodiment of the present invention, a heart sound signal storage unit 235, a pulse wave signal storage unit 232, and a blood pressure data storage unit 233 are provided. The heart sound signal storage unit 235 is used to store the heart sound signals output from the heart sound sensor 60.

[0199] The control unit 21 has a heart sound signal acquisition unit 223 and a second heart sound detection unit 224 in place of the processing functions of the ECG signal acquisition unit 211 and the ECG feature quantity detection unit 212 described in the first embodiment. These processing units 223 and 224 are also implemented by causing the hardware processor of the control unit 21 to execute the programs stored in the program storage unit 22 in the same manner as the other processing units 213 to 218.

[0200] The heart sound signal acquisition unit 223 performs the following processing: introduces the heart sound signals output from the heart sound detection circuit 62 of the heart sound sensor 60, and causes the heart sound signal storage unit 235 to store the heart sound signals in chronological order. The second heart sound detection unit 224 performs the following processing: reads the heart sound signals from the heart sound signal storage unit 235, and detects the rising edge HS of the second heart sound for each heartbeat, which is one of the characteristic quantities of the heart sound signals. It should be noted that the characteristic quantities of the heart sound signals are not limited to the second heart sound, and may also be other characteristic quantities such as the first heart sound.

[0201] The pulse wave conduction time calculation unit 215 performs the following processing: calculates the pulse wave conduction time (PTT) for each heartbeat based on the time difference between the rising edge HS of the second heart sound detected by the second heart sound detection unit 224 and the rising edge PS of the pulse wave detected by the pulse wave feature quantity detection unit 214.

[0202] The blood pressure estimation unit 216 performs the following processing in the same manner as in the first embodiment: estimating the blood pressure value corresponding to the calculated pulse wave transit time (PTT) using a conversion table representing the relationship between PTT and blood pressure values or using a conversion formula.

[0203] The light emission control unit 237 supplies a light emission control signal for intermittently driving the LED 411 of the pulse wave sensor 40 to the pulse driving unit 42 and has, for example, the following processing functions.

[0204] (1) Set a preparation mode before the start of the blood pressure measurement operation, and estimate the time correlation between the heart sound signal and the pulse wave signal during a preset preparation period. For example, calculate the PTT for each of multiple heartbeats included in the above preparation period, and calculate its average value. Then, based on the calculated average PTT value, set the light emission control mode of the LED 411. The light emission period of the light emission control mode is set to include at least a certain interval before and after the pulse wave rising edge PS of the pulse wave signal.

[0205] Note that instead of the average PTT value, the length of the light emission period can be set based on the maximum value of the PTT obtained during the above preparation period. In this way, even if the heart rate interval becomes longer due to some reason, the pulse wave rising edge PS of the pulse wave signal can be detected with a high probability.

[0206] (2) In the blood pressure measurement mode after the end of the above preparation mode, whenever the rising edge HS of the second heart sound of the heart sound signal is detected, a light emission control signal for intermittently driving the LED 411 of the pulse wave sensor 40 is generated in synchronization with the detection timing of the rising edge HS of the second heart sound according to the light emission control mode set in the above preparation mode. Then, the generated light emission control signal is supplied to the pulse driving unit 42 of the pulse wave sensor 40.

[0207] (Operation example)

[0208] Next, the operation of the blood pressure measurement device configured as above will be described.

[0209] Figure 25 and Figure 26 are flowcharts showing the processing procedures and processing contents performed by the control unit 21 of the blood pressure measurement unit 20. Note that in Figure 25 and Figure 26 , for the steps with the same processing contents as those in the above Figure 7 and Figure 8 , the same symbols are used for explanation.

[0210] (1) Preparation mode

[0211] When the person to be measured operates the operation unit 13 to input a measurement start request after attaching the attachment unit 10 to his / her upper arm 1, in the blood pressure measurement unit 20, through step S10, the above measurement start request is detected. As a result, the power supply voltage Vcc is supplied from the power supply circuit 25 to each part in the device, and the blood pressure measurement unit 20 and the attachment unit 10 are in an operating state.

[0212] When in the operating state, under the control of the light emission control unit 237, the blood pressure measurement unit 20 first generates a continuous light emission control signal in step S11, and supplies the generated continuous light emission control signal to the pulse drive unit 42 of the pulse wave sensor 40. As a result, through the pulse drive unit 42, the LED 411 continuously performs a light emission operation, and thus a pulse wave signal is continuously output from the pulse wave sensor 40.

[0213] In this state, in step S122, the blood pressure measurement unit 20 acquires the heart sound signal output from the above heart sound sensor 60 through the heart sound signal acquisition unit 223, and temporarily stores the heart sound signal in the heart sound signal storage unit 235. In addition, in step S13, the blood pressure measurement unit 20 acquires the pulse wave signal output from the above pulse wave sensor 40 through the pulse wave signal acquisition unit 213, and temporarily stores the pulse wave signal in the pulse wave signal storage unit 232. Then, in step S142, the blood pressure measurement unit 20 reads the heart sound signal from the heart sound signal storage unit 235 through the second heart sound detection unit 224, and detects the rising edge HS of the second heart sound as one of its characteristic quantities. In addition, at the same time, the pulse wave characteristic quantity detection unit 214 reads the pulse wave signal from the pulse wave signal storage unit 232, and detects the rising edge PS of the pulse wave as one of its characteristic quantities.

[0214] Next, in step S15, the blood pressure measurement unit 20 calculates the time difference between the detection timing of the rising edge HS of the above detected second heart sound and the detection timing of the rising edge PS of the pulse wave, and temporarily stores the calculated time difference as the pulse wave conduction time (PTT) in the current heartbeat in the PTT data storage unit (not shown) in the data storage unit 23.

[0215] Then, in step S16, the blood pressure measurement unit 20 monitors whether a preset preparation period has elapsed. If not, it returns to step S11, and repeatedly executes the process of calculating the PTT for each heartbeat through steps S11 to S15. It should be noted that the above preparation period is set to the average time required for the heartbeat to stabilize, for example, it is set to the time corresponding to 10 to 20 heartbeats. However, the length of the preparation period is not limited to this.

[0216] On the other hand, when the above-mentioned preparation period has elapsed, the blood pressure measurement unit 20 temporarily returns the LED 411 of the pulse wave sensor 40 from the continuous light emission state to the extinguished state. Then, in step S17, the light emission control unit 237 calculates, for example, the average value of each PTT for each heartbeat calculated during the above-mentioned preparation period, and sets a light emission control mode for intermittently driving the LED 411 of the pulse wave sensor 40 to emit light based on the calculated average value of PTT, that is, sets the lengths of the light emission period and the extinguished period. It should be noted that a representative operation example of this light emission control mode will be described in detail later.

[0217] (2) Blood pressure measurement mode

[0218] When the setting of the above-mentioned light emission control mode in the preparation mode is completed, the blood pressure measurement unit 20 then starts the control operation of blood pressure measurement for each heartbeat as follows.

[0219] That is, first in step S182, the blood pressure measurement unit 20 acquires the heart sound signal output from the above-mentioned heart sound sensor 60 through the heart sound signal acquisition unit 223, and temporarily stores the heart sound signal in the heart sound signal storage unit 235. Then, in step S192, the second heart sound detection unit reads the above-mentioned heart sound signal from the heart sound signal storage unit 235, detects the rising edge HS of the second heart sound from the read heart sound signal, and saves the detection timing in a feature quantity storage unit (not shown) in the data storage unit 23.

[0220] Next, in step S20, under the control of the light emission control unit 237, the blood pressure measurement unit 20 generates a light emission control signal for starting the light emission of the LED 411 of the pulse wave sensor 40 in synchronization with the detection timing of the rising edge HS of the second heart sound according to the light emission control mode set in the above-mentioned preparation mode, and provides it to the pulse drive unit 42 of the pulse wave sensor 40. As a result, the LED 411 of the pulse wave sensor 40 starts to emit light, and the pulse wave signal of the measured person is output from the pulse wave sensor 40.

[0221] In step S21, the blood pressure measurement unit 20 acquires the pulse wave signal output from the above-mentioned pulse wave sensor 40 through the pulse wave signal acquisition unit 213, and temporarily stores the pulse wave signal in the pulse wave signal storage unit 232. Then, in step S22, the pulse wave feature quantity detection unit 214 reads the above-mentioned pulse wave signal from the pulse wave signal storage unit 232, and detects the pulse wave rising edge PS from the pulse wave signal. Then, when the pulse wave rising edge PS is detected, the detection timing is saved in the data storage unit 23.

[0222] In addition, under the control of the light emission control unit 237, the blood pressure measurement unit 20 monitors the end timing of the light emission period specified by the above light emission control mode in step S23. Then, when the light emission period ends, the light emission of the LED 411 of the pulse wave sensor 40 is stopped in step S24.

[0223] When the blood pressure measurement unit 20 detects the above-mentioned pulse wave rising edge PS, in step S25, the pulse wave conduction time calculation unit 215 calculates the time difference between the detection timing of the rising edge HS of the second heart sound detected previously in step S192 and the detection timing of the pulse wave rising edge PS of the above-mentioned pulse wave signal detected in step S22 as the PTT of the current heartbeat. Then, in step S26, the blood pressure estimation unit 216 estimates the blood pressure value based on the calculated PTT, and causes the blood pressure data storage unit 233 to store the estimated blood pressure value in association with the detection timing of the rising edge HS of the above-mentioned second heart sound, that is, the identification information of the heartbeat. As a result, the blood pressure data storage unit 233 stores the blood pressure value of one heartbeat of the subject.

[0224] In addition, while the blood pressure measurement unit 20 executes the process for the above-mentioned blood pressure measurement, it monitors the input of the display / transmission request of the blood pressure data in step S27 through the blood pressure data output unit 218. Then, for example, when the subject performs an operation for the display / transmission request through the operation unit 13, under the control of the blood pressure data output unit 218, the blood pressure data is read out from the blood pressure data storage unit 233 in step S28 and the display unit 14 displays the blood pressure data, or the blood pressure data is transmitted from the communication unit 24 to the information terminal.

[0225] In addition, while the blood pressure measurement unit 20 executes the process for the above-mentioned blood pressure measurement, it monitors the input of the measurement end request in step S29. In this state, for example, when the subject performs an operation requesting the end of the measurement through the operation unit 13, the blood pressure measurement unit 20 ends the process for blood pressure measurement and stops supplying the power supply voltage Vcc from the power supply circuit 25 to each unit.

[0226] It should be noted that after the power supply is ended, the blood pressure data stored in the blood pressure data storage unit 233 is also retained. In addition, for example, it is preferable to save the light emission control mode set by the light emission control unit 237 in association with the identification information of the subject in the data storage unit 23. In this way, when the blood pressure of the same subject is measured next time, the blood pressure measurement can be immediately started based on the light emission control mode corresponding to the subject.

[0227] (Representative operation example)

[0228] Next, a representative operation example in the third embodiment will be described. It should be noted that the operation example is not limited to the following examples, and various other operation examples can be considered.

[0229] Figure 27 It is a signal waveform diagram for explaining a representative operation example in the third embodiment.

[0230] First, during the preparation period, the blood pressure measurement unit 20 calculates the PTT according to the time difference between the rising edge HS of the second heart sound of the heart sound signal and the pulse wave rising edge PS of the pulse wave signal for each heartbeat, and obtains the average value of the PTT of each heartbeat during the preparation period. Then, the light emission period of the light emission control mode is set to a period T10 that is longer than the average value of the PTT by a specified time, and the extinguishing period is set to a period T11 until the rising edge HS of the second heart sound of the next heartbeat is detected.

[0231] Next, in the blood pressure measurement mode, when the blood pressure measurement unit 20 detects the rising edge HS of the second heart sound of the heart sound signal, it starts the light emission of the LED 411 of the pulse wave sensor 40 at the detection timing of the rising edge HS of the second heart sound. Then, the pulse wave sensor 40 operates and a pulse wave signal is output. The blood pressure measurement unit 20 detects the pulse wave rising edge PS from the output pulse wave signal. Then, the time difference between the detection timing of the rising edge HS of the second heart sound of the heart sound signal and the detection timing of the pulse wave rising edge PS of the pulse wave signal is calculated as the PTT in one heartbeat, and the blood pressure value is estimated based on the PTT.

[0232] In addition, when the length of the light emission period reaches the set value T10 of the light emission period set in the above preparation mode during the light emission operation of the LED 411 of the pulse wave sensor 40, the blood pressure measurement unit 20 turns off the LED 411 of the pulse wave sensor 40. Then, this extinguished state is maintained until the rising edge HS of the second heart sound of the next heartbeat is detected.

[0233] After that, similarly, the blood pressure measurement unit 20 repeatedly performs the following process: whenever the rising edge HS of the second heart sound of the heart sound signal is detected, the LED 411 of the pulse wave sensor 40 is intermittently turned on synchronously with the detection timing of the rising edge HS of the second heart sound, and the blood pressure value of each heartbeat is measured.

[0234] According to this operation example, the LED 411 of the pulse wave sensor 40 emits light only for the light emission period T10 set during the preparation period in synchronization with the rising edge of the second heart sound detected from the heart sound signal every heartbeat. Therefore, compared with the case where the LED 411 of the pulse wave sensor 40 is always lit, the power consumption caused by the LED 411 of the pulse wave sensor 40 can be reduced, and thus the blood pressure can be continuously measured throughout the sleep period even without using a large-capacity battery 251.

[0235] Moreover, according to this operation example, the light emission period T10 of the LED 411 of the pulse wave sensor 40 is set to a value that starts from the detection timing of the rising edge HS of the second heart sound of the heart sound signal and is longer than the PTT value by a specified length. Therefore, the pulse wave rising edge PS of the pulse wave signal can be reliably detected without omission. Thus, the blood pressure for each heartbeat can be measured without data loss.

[0236] Note that in the third embodiment, for example, an extinguishing period may be set within the light emission period T10 as Figure 10 illustrated by way of example, and in addition, for example, a light emission period may be intermittently set within the above-mentioned extinguishing period T11 as Figure 11 illustrated by way of example. Moreover, a light emission period may be set after a waiting period as Figure 12 or Figure 14 illustrated by way of example, and in addition, the end timing of the light emission period may be set in synchronization with the detection timing of the pulse wave rising edge PS of the pulse wave signal as Figure 13 illustrated by way of example.

[0237] In addition, as a characteristic quantity of the heart sound signal, in addition to the second heart sound, the first heart sound and other characteristic quantities may also be detected.

[0238] [Other Embodiments]

[0239] In each of the above embodiments, a preparation mode is provided. In this preparation mode, the R-wave peak RP of the ECG signal, the pulse wave rising edge PS1 of the first pulse wave signal, or the rising edge HS of the second heart sound of the heart sound signal is detected, and the PTT is measured. The light emission control mode is set based on the detection timing of the above R-wave peak RP, pulse wave rising edge PS1, or second heart sound rising edge HS and the average value during the preparation period of the above PTT. However, the preparation mode is not necessarily required, and the light emission period of the light emission control mode may also be fixedly set in advance based on a general PTT value.

[0240] In addition, as types of biological signals associated with the pulsation of the heart, in addition to ECG signals and pulse wave signals, it is also possible to detect the impedance of the skin that changes according to the vibration of blood vessels. In addition, regarding the configuration, processing process, and processing content of the biological signal measurement device, the configuration of the light emission control mode of the light emitting element of the pulse wave sensor, etc., various modifications can also be made and implemented without departing from the gist of the present invention.

[0241] As described above, each embodiment of the present invention has been described in detail, but the foregoing description is merely an example of the present invention in all aspects, and of course, various improvements and modifications can be made without departing from the scope of the present invention. That is to say, when implementing the present invention, specific configurations corresponding to each embodiment can also be appropriately adopted.

[0242] In addition, for the present invention, various inventions can be constituted by appropriately combining a plurality of constituent elements disclosed in the above-described respective embodiments. For example, several constituent elements can also be deleted from all the constituent elements shown in each embodiment. Moreover, constituent elements in different embodiments can be appropriately combined.

[0243] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from its gist at the implementation stage. In addition, each embodiment can also be appropriately combined and implemented, and in this case, the combined effects can be obtained. Moreover, various inventions are included in the above-described embodiments, and various inventions can be extracted by combinations selected from the plurality of disclosed constituent elements. For example, when a problem can be solved and an effect can be obtained even if several constituent elements are deleted from all the constituent elements shown in the embodiment, the configuration obtained by deleting the constituent elements can be extracted as an invention.

[0244] Explanation of reference numerals

[0245] 1: Upper arm part;

[0246] 2: Bone part;

[0247] 3: Artery;

[0248] 10: Mounting unit;

[0249] 11: Belt part;

[0250] 12: Mounting unit circuit part;

[0251] 13: Operation part;

[0252] 14: Display part;

[0253] 20: Blood pressure measurement unit;

[0254] 21: Control part;

[0255] 22: Program storage unit;

[0256] 23: Data storage unit;

[0257] 24: Communication unit;

[0258] 25: Power supply circuit;

[0259] 211: ECG signal acquisition unit;

[0260] 212: ECG feature quantity detection unit;

[0261] 213, 221: Pulse wave signal acquisition unit;

[0262] 214, 222: Pulse wave feature quantity detection unit;

[0263] 215: Pulse wave conduction time calculation unit;

[0264] 216: Blood pressure estimation unit;

[0265] 217, 227, 237: Light emission control unit;

[0266] 218: Blood pressure data output unit;

[0267] 223: Heart sound signal acquisition unit;

[0268] 224: Second heart sound detection unit;

[0269] 231: ECG signal storage unit;

[0270] 232, 234: Pulse wave signal storage unit;

[0271] 233: Blood pressure data storage unit;

[0272] 235: Heart sound signal storage unit;

[0273] 251: Battery;

[0274] 30: ECG sensor;

[0275] 31: Electrode group;

[0276] 32: ECG detection unit;

[0277] 321: Switching circuit;

[0278] 322: Subtraction circuit;

[0279] 323: AFE;

[0280] 40, 50: Pulse wave sensor;

[0281] 41, 51: Photoelectric sensor;

[0282] 411, 511: LED;

[0283] 412, 512: PD;

[0284] 42, 52: Pulse drive unit;

[0285] 421, 521: Power-on and voltage detection circuit;

[0286] 60: Heart sound sensor;

[0287] 61: Piezoelectric sensor;

[0288] 62: Heart sound detection circuit;

[0289] 621: Heart sound frequency band detection unit;

[0290] 622: A / D.

Claims

1. A biological signal measurement device, the measurement device comprising: A first acquisition unit that acquires a first biological signal related to the pulsation of the heart of the person to be measured from a first sensor; A second acquisition unit that acquires a second biological signal related to the pulsation of the heart of the subject from a second sensor using a light-emitting element; A first detection unit that detects a first feature quantity from the acquired first biological signal; And A light emission control unit that intermittently drives the light-emitting element of the second sensor based on the detection timing of the first feature quantity and information indicating the time correlation between the first biological signal and the second biological signal, and estimates the information on the time correlation based on the pulse wave conduction time calculated for each of multiple heartbeats included during a preset preparation period. The light emission control unit causes the light-emitting element to emit light within a first period determined based on the information indicating the time correlation in synchronization with the detection timing of the first feature quantity, and causes the light-emitting element to be extinguished within a second period until the next detection of the first feature quantity after the first period has elapsed. The light emission control unit sets the first period after a period corresponding to at least one cycle of the first biological signal has elapsed since the detection timing of the first feature quantity.

2. The biological signal measurement device according to claim 1, wherein: The light emission control unit causes the light-emitting element to be extinguished during at least a part of the first period.

3. The biological signal measurement device according to claim 1 or 2, wherein: The light emission control unit causes the light-emitting element to emit light during at least a part of the second period.

4. The biological signal measurement device according to claim 1, wherein: It further includes: a second detection unit that detects a second feature quantity from the second biological signal. The light emission control unit causes the lighting of the light-emitting element within the first period to end in synchronization with the detection timing of the second feature quantity.

5. The biological signal measurement device according to claim 1, wherein: When the first sensor is constituted by a sensor that measures a pulse wave using a light-emitting element, the light emission control unit drives the light-emitting element of the first sensor in a manner opposite to the intermittent light emission driving of the light-emitting element of the second sensor with respect to the light emission period and the extinguished period.

6. A biological signal measurement device, the measurement device comprising: A first acquisition unit that acquires a first biological signal related to the pulsation of the heart of the person to be measured from a first sensor; A second acquisition unit that acquires a second biological signal related to the pulsation of the heart of the subject from a second sensor using a light-emitting element; A first detection unit that detects a first feature quantity from the acquired first biological signal; And A light emission control unit that intermittently drives the light-emitting element of the second sensor based on the detection timing of the first feature quantity and information indicating the time correlation between the first biological signal and the second biological signal, and estimates the information on the time correlation based on the pulse wave conduction time calculated for each of multiple heartbeats included during a preset preparation period. The light emission control unit starts lighting the light-emitting element at a time point after a third period set based on the information indicating the time correlation has elapsed since the detection timing of the first feature quantity, and causes the light-emitting element to be extinguished at a time point after a preset fourth period has elapsed since the start of the lighting. The light emission control unit sets the fourth period after a period corresponding to at least one cycle of the first biological signal has elapsed since the detection timing of the first feature quantity.

7. The biological signal measurement device according to claim 6, wherein: It further includes: a second detection unit that detects a second feature quantity from the second biological signal. The light emission control unit ends the lighting of the light emitting element in the fourth period in synchronization with the detection timing of the second feature amount.

8. The biological signal measurement device according to claim 1 or 6, wherein: The first acquisition unit acquires any one of an electrocardiogram signal, a pulse wave signal, a detection signal of heart sound, and a detection signal of skin impedance that changes according to the vibration of blood vessels as the first biological signal, and the second acquisition unit acquires a pulse wave signal as the second biological signal.

9. A biological signal measurement method, which is a biological signal measurement method executed by a device for measuring the biological signal of a person to be measured, and which comprises: A process of acquiring a first biological signal related to the pulsation of the heart of the person to be measured from a first sensor; A process of obtaining a second biological signal related to the pulsation of the heart of the subject from a second sensor using a light-emitting element; A process of detecting a first feature amount from the acquired first biological signal; And A process of intermittently driving the light emitting element of the second sensor based on the detection timing of the first feature amount and information indicating the time correlation between the first biological signal and the second biological signal, and estimating the information of the time correlation based on the pulse wave conduction time calculated respectively from multiple heartbeats included in a preset preparation period. In the process of performing the light emission driving, the light emitting element is caused to emit light in a first period determined based on the information indicating the time correlation in synchronization with the detection timing of the first feature amount, and after the first period has elapsed, the light emitting element is caused to go out in a second period until the next detection of the first feature amount. In the process of performing the light emission driving, the first period is set after a period of at least one cycle of the first biological signal has elapsed from the detection timing of the first feature amount.

10. A computer-readable recording medium storing a program that causes a hardware processor included in the biological signal measurement device according to any one of claims 1 to 8 to execute processing of at least the light emission control unit among the respective units included in the biological signal measurement device.

11. A biological signal measurement method, which is a biological signal measurement method executed by a device for measuring a biological signal of a subject, the method comprising: A process of obtaining a first biological signal related to the pulsation of the heart of the subject from a first sensor; A process of obtaining a second biological signal related to the pulsation of the heart of the subject from a second sensor using a light-emitting element; A process of detecting a first feature amount from the acquired first biological signal; And A process of intermittently driving the light emitting element of the second sensor based on the detection timing of the first feature amount and information indicating the time correlation between the first biological signal and the second biological signal, and estimating the information of the time correlation based on the pulse wave conduction time calculated respectively from multiple heartbeats included in a preset preparation period. In the process of performing the light emission driving, the lighting of the light emitting element starts at a time point after a third period set based on the information indicating the time correlation has elapsed from the detection timing of the first feature amount, and the light emitting element is caused to go out at a time point after a preset fourth period has elapsed since the start of the lighting. In the process of performing the light emission driving, the fourth period is set after a period of at least one cycle of the first biological signal has elapsed from the detection timing of the first feature amount.

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