JP2023018344A - Biological information detection device - Google Patents

Abstract

To provide a biological information detection device capable of detecting blood pressure of an object person while suppressing a hindrance to an action of the object person.SOLUTION: A biological information detection device 1 includes a reception antenna 13 for receiving a radio wave radiated from a transmission antenna 12 and transmitted through an object person, and an input unit 21 for acquiring a reception signal according to the radio wave received by the reception antenna 13 when the radio wave is radiated from the transmission antenna 12. The biological information detection device 1 includes a pulse wave sensor 15 for detecting a time waveform of the pulse wave of the object person, and a processing unit 24 for calculating blood pressure of the object person as biological information. The processing unit 24 calculates the blood pressure by calculating a physical amount correlated with the blood pressure from a time waveform of a signal component generated resulting from the movement of the heart of the object person from the reception signal, and correcting the physical amount on the basis of the time waveform of the pulse wave.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a biometric information detection device that detects biometric information of a subject.

Conventionally, while constantly detecting the pulse wave with a photoelectric pulse wave sensor attached to the finger of the subject, constantly observing the timing of the appearance of the R wave in the electrocardiogram, based on these results, have a correlation with the heartbeat A device that measures the pulse wave transit time is known (see, for example, Patent Document 1).

JP-A-10-66681

However, the device described in Patent Document 1 detects a physical quantity correlated with the heartbeat in a state in which an electrode for observing the R wave of the electrocardiogram and a pulse wave sensor for detecting the pulse wave are attached to the subject. There is a need. In this case, when the blood pressure of the subject is detected, the body of the subject is restrained at two or more points, and the behavior of the subject is greatly hindered.

An object of the present disclosure is to provide a biological information detection device capable of detecting a subject's blood pressure while suppressing hindrance to the subject's actions.

The invention according to claim 1,
A biological information detection device for detecting biological information of a subject,
a receiving antenna (13) for receiving radio waves radiated from the transmitting antenna (12) and transmitted through the subject;
a signal acquisition unit (21) for acquiring a received signal corresponding to the radio wave received by the receiving antenna when the radio wave is radiated from the transmitting antenna;
a pulse wave detection device (15, 16, 24, 25, 30) for detecting the time waveform of the subject's pulse wave;
A calculation unit (24) that calculates the subject's blood pressure as biological information,
The calculation unit calculates the physical quantity correlated with blood pressure from the time waveform of the signal component generated from the received signal due to the movement of the heart of the subject, and calculates the blood pressure by correcting the physical quantity based on the time waveform of the pulse wave. do.

According to this, at least the physical quantity correlated with the blood pressure is calculated based on the radio waves that have passed through the subject, so that the body of the subject can be restrained from being restricted when the blood pressure is detected. Therefore, it is possible to measure the blood pressure of the subject while suppressing interference with the subject's behavior.

It should be noted that the reference numerals in parentheses attached to each component etc. indicate an example of the correspondence relationship between the component etc. and specific components etc. described in the embodiments described later.

1 is a schematic configuration diagram of a biological information detection device according to a first embodiment; FIG. FIG. 2 is a schematic diagram showing an example of an arrangement of transmitting antennas and receiving antennas; FIG. 4 is an explanatory diagram for explaining electrocardiogram data; FIG. 4 is an explanatory diagram for explaining a time waveform of a reception signal corresponding to radio waves received by a reception antenna; It is a flow chart which shows a flow of processing which an information control part of a living body information detecting device concerning a 1st embodiment performs. FIG. 4 is an explanatory diagram for explaining the relationship between the time waveform of a received signal and the time waveform of a pulse wave, which is a sensor output of a pulse wave sensor; FIG. 4 is an explanatory diagram for explaining the correlation between the variation amount of the component extracted from the received signal and the contraction amount of the ventricle; It is a schematic block diagram of the biometric information detection apparatus which concerns on 2nd Embodiment. It is a schematic block diagram of the biometric information detection apparatus which concerns on 3rd Embodiment. It is an explanatory view for explaining some blood vessels in the body. FIG. 4 is an explanatory diagram for explaining frequency characteristics of a sub-received signal according to radio waves received by a sub-antenna;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same or equivalent parts as those described in the preceding embodiments are denoted by the same reference numerals, and description thereof may be omitted. Moreover, when only some of the components are described in the embodiments, the components described in the preceding embodiments can be applied to the other parts of the components. The following embodiments can be partially combined with each other, even if not explicitly stated, as long as there is no problem with the combination.

(First embodiment)
This embodiment will be described with reference to FIGS. 1 to 7. FIG. In this embodiment, an example will be described in which the blood pressure of one of the occupants P seated on the seat S of the vehicle is calculated as the biological information using the biological information detection device 1 of the present disclosure.

In recent years, more and more attention is being paid to preventive medicine, which is based on daily health management and the like, rather than treatment after the symptoms of a disease appear. Blood pressure is an index used for daily health management. Blood pressure is one of the indicators for measuring the degree of burden on the heart H, and is an essential item in health checkups in Japan. However, since blood pressure varies depending on the time of measurement, meal before measurement, tension, etc., it is recommended to check the change in blood pressure not only at the time of annual health checkup, but also once a day at the same time, for example. . One that is considered suitable for the environment is commuting time using a vehicle. However, since there is a requirement that the driver should not interfere with driving while riding in the vehicle, there is a demand for unrestricted blood pressure detection.

In consideration of these, the biological information detection device 1 includes a radio wave transmission type device that detects a physical quantity correlated with the blood pressure of the occupant P based on the radio wave signal transmitted through the occupant P. The biological information detecting device 1 calculates the blood pressure of the passenger P seated in the driver's seat DS among the seats S of the vehicle as a target. The biological information detection device 1 includes a transmitter 11 , a transmission antenna 12 , a reception antenna 13 , a receiver 14 , a pulse wave sensor 15 and an information control section 20 .

The transmitter 11 outputs a transmission signal of a predetermined frequency (for example, a frequency of 900 MHz band) to the transmission antenna 12 . The transmitting antenna 12 is arranged on the front side of the driver's seat DS in the traveling direction of the vehicle in the instrument panel inside the vehicle. The transmission antenna 12 transmits a radio signal corresponding to the transmission signal from the transmitter 11 toward the upper half of the body of the passenger P seated in the driver's seat DS.

As shown in FIG. 2, the receiving antenna 13 is arranged to face the transmitting antenna 12 with the occupant P seated in the driver's seat DS therebetween. The receiving antenna 13 of this embodiment is attached to the seat back of the driver's seat DS. The receiving antenna 13 is configured to receive radio waves transmitted from the transmitting antenna 12 . The receiving antenna 13 receives radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P who is a target person.

The receiver 14 amplifies and outputs the radio signal received by the receiving antenna 13 . Specifically, the receiver 14 amplifies the radio wave signal received by the receiving antenna 13 and outputs it to the information control section 20 as the biological signal P1.

The pulse wave sensor 15 is a wearable sensor that is worn on the body of the occupant P and sequentially detects the pulse wave of the occupant P. As shown in FIG. The pulse wave sensor 15 detects the pulse wave of the part of the occupant P's body where the sensor unit is attached. Pulse wave sensor 15 may be, for example, a photoelectric pulse wave sensor, an impedance pulse wave sensor, or the like. The pulse wave sensor 15 detects, as a waveform, changes in blood vessel volume that occur as the heart H pumps out blood. In this embodiment, the pulse wave sensor 15 constitutes a pulse wave detection device for detecting the time waveform of the pulse wave of the occupant P, who is a subject.

The information control unit 20 calculates the blood pressure of the occupant P as biological information based on the biological signal P1 acquired from the receiver 14 and the temporal waveform of the pulse wave detected by the pulse wave sensor 15 . The information control section 20 includes an input section 21 , a storage section 22 , an output section 23 and a processing section 24 .

The input unit 21 is a signal acquiring unit that acquires a reception signal corresponding to the radio wave received by the receiving antenna 13 when the radio wave is radiated from the transmitting antenna 12 . The input unit 21 outputs the biological signal P1, which is an analog signal input from the receiver 14, to the processing unit 24 as a digital signal.

The storage unit 22 includes RAM, ROM, writable nonvolatile memory, and the like. The RAM, ROM, and writable non-volatile memory that constitute the storage unit 22 are all non-transitional material storage media.

The output unit 23 outputs the signal input from the processing unit 24 to a device external to the information control unit 20 . The external device of the output destination may be, for example, an in-vehicle navigation device that performs route guidance, an in-vehicle data communication module that communicates with the outside of the vehicle, or a mobile communication terminal that the passenger P carries.

The processing unit 24 is a device that executes processing according to a program recorded in the ROM of the storage unit 22 or a writable nonvolatile storage medium. The processing unit 24 of this embodiment uses the RAM of the storage unit 22 as a work area. The processing unit 24 functions as a calculation unit that calculates the blood pressure of the occupant P as biological information.

Here, the information control unit 20 is connected to an in-vehicle network via CAN communication. CAN is an abbreviation for Controller Area Network. The information control unit 20 is connected to a CAN bus 30, which is a communication bus. In-vehicle equipment including the pulse wave sensor 15 is connected to the CAN bus 30 . The information control unit 20 can acquire the time waveform of the pulse wave detected by the pulse wave sensor 15 via the CAN bus 30 . The information control unit 20 and the pulse wave sensor 15 may be connected by another connection means without passing through the CAN bus 30, or may be directly connected.

Next, the operation of the biological information detection device 1 will be described. Transmitter 11 outputs a transmission signal of a predetermined frequency to transmission antenna 12 . The transmission antenna 12 transmits radio waves corresponding to the transmission signal from the transmitter 11 toward the passenger P sitting in the driver's seat DS. Part of the radio wave transmitted from the transmitting antenna 12 is received by the receiving antenna 13 after passing through the occupant P in the driver's seat DS.

The body of the occupant P functions as a dielectric for radio waves. Therefore, when radio waves pass through the body of the occupant P, dielectric loss occurs in the electric field strength of the radio waves. In the body of the occupant P, the heart H changes its shape as it expands and contracts. Therefore, in the radio waves that pass through the heart H and reach the receiving antenna 13, the dielectric loss that occurs in the electric field strength changes according to the movement of the heart H. FIG.

In this way, the strength of the received signal received by the receiving antenna 13 includes a component that periodically changes according to the motion of the heart H. FIG. Therefore, the level of the electrical signal output from the receiving antenna 13 to the receiver 14 when the receiving antenna 13 receives the radio waves from the transmitting antenna 12 includes a component that fluctuates according to the movement of the heart H.

Here, FIG. 3 shows electrocardiogram data, the horizontal axis indicates time, and the vertical axis indicates the amplitude of the waveform of the electrocardiogram. Electrocardiogram data is a record of electrical energy generated when the heart H contracts. The movement of the heart H is reflected in the electrocardiogram data. That is, electrocardiogram data includes components that fluctuate according to the motion of the heart H. FIG. Specifically, as shown in FIG. 3, the contraction of the atria of the heart H corresponds to the P wave of an electrocardiogram. The contraction of the ventricles of heart H corresponds to the QRS wave following the P wave. The voltage of the QRS wave is greater than that of the P wave.

The heart H repeats the contraction of the atria and the ventricles, so that the blood entering from the atria is pushed into the ventricles and sent out of the heart H from the ventricles. Specifically, blood is pumped from the right ventricle to the lungs and from the left ventricle to the body. Therefore, the amount of contraction of the left ventricle is proportional to the amount of blood ejected from the heart H to the whole body. Blood pressure changes according to the amount of blood pumped out from the heart H to the whole body and vascular resistance. Therefore, the blood pressure and the movement of the heart H have a certain correlation.

The strength of the received signal received by the receiving antenna 13 of the biological information detection device 1 changes according to the movement of the heart H, as with the electrocardiogram data. The motion of the heart H includes two stages of motion of the atrium and the ventricle. Correspondingly, the time waveform of the received signal varies in signal strength in two steps, as shown in FIG. According to investigations and studies by the inventors, it has been found that the change in the signal strength of the received signal increases when the ventricle contracts. Specifically, the amount of contraction of the ventricles of the heart H has a strong correlation with the maximum amount of change ΔA in the signal intensity of the received signal.

In consideration of these factors, the biological information detection apparatus 1 of the present embodiment extracts a characteristic change amount from changes in the signal intensity of the received signal in a predetermined period as the contraction amount of the ventricle of the heart H, and based on the component, to calculate the subject's blood pressure.

Here, blood flow rate and resistance contribute to blood pressure in the same manner as voltage V, current I, and resistance in Ohm's law. Flow rate is the ejection volume of blood pumped from the ventricles of the heart H to the whole body. As described above, the amount of blood ejected has a strong correlation with the amount of contraction of the ventricles of the heart H, and can be grasped by extracting the amount of contraction of the ventricles of the heart H from changes in the signal intensity of the received signal. .

On the other hand, resistance is vascular resistance that indicates the difficulty of blood flow in blood vessels. Since this vascular resistance differs from person to person, it is necessary to grasp it for each person in order to accurately detect blood pressure. Vascular resistance can be obtained by calibration using a dedicated kit that simultaneously obtains blood ejection volume and blood pressure.

However, when a user performs calibration using a dedicated kit, the user needs to prepare the dedicated kit and operate the kit. For this reason, it is practically difficult for the user to perform the above calibration, and he or she has no choice but to ask a specialist such as a dealer to handle the calibration.

In consideration of these, the biological information detection device 1 of the present embodiment is configured to grasp the vascular resistance from the pulse wave delay by utilizing the strong correlation between the vascular resistance and the pulse wave delay. ing. Grasping of the blood vessel resistance is realized by arithmetic processing in the processing section 24 of the information control section 20 . The flow of processing executed by the processing section 24 of the information control section 20 will be described below with reference to FIG. The processing shown in FIG. 5 is periodically or irregularly executed by the information control unit 20 while the passenger P is seated in the driver's seat DS of the vehicle.

As shown in FIG. 5, in step S100, the processing unit 24 acquires, via the receiver 14, the time waveform of the reception signal received by the reception antenna 13 when radio waves are transmitted from the transmission antenna 12. . In addition, the processing unit 24 sequentially acquires the time waveform of the pulse wave at the occupant P's fingertip from the pulse wave sensor 15 .

Here, the time waveform of the received signal is the time variation of the signal strength of the received signal, and has waveforms as shown in the upper stages of FIGS. 4 and 6, for example. The time waveform of the received signal includes a component correlated with the motion of the ventricle of the heart H. FIG. Also, the time waveform of the pulse wave becomes a waveform as shown in the lower part of FIG. A pulse wave is generated as the heart H pumps out blood. Therefore, the time waveform of the pulse wave has characteristics corresponding to the time waveform of the received signal.

Subsequently, in step S110, the processing unit 24 determines whether or not the storage unit 22 stores the pulse wave delay time ΔT of the passenger P seated in the driver's seat DS. This determination processing is performed based on information stored in the storage unit 22 .

If the delay time ΔT is not stored in the storage unit 22, the processing unit 24 proceeds to step S120. On the other hand, if the delay time ΔT is stored in the storage unit 22, the process skips steps S120 and S130 and proceeds to step S140.

In step S120, the processing unit 24 detects the second feature amount corresponding to the first feature amount A in the time waveform of the pulse wave after the first feature amount A appears in the time waveform of the signal component of the received signal. The time until B develops is detected as the delay time ΔT.

The processing unit 24 identifies, as the first feature amount A, the point at which the amplitude is maximum in the time waveform of the signal component of the received signal, for example. In addition, the processing unit 24 identifies a point corresponding to the first feature amount A as the second feature amount B in the temporal waveform of the pulse wave. For example, the processing unit 24 identifies, as the second feature amount B, the point at which the amplitude first becomes maximum in the temporal waveform of the pulse wave after the timing at which the first feature amount A appears.

Then, the processing unit 24 detects the time from the timing when the first feature amount A appears until the second feature amount B appears as the delay time ΔT. For example, the processing unit 24 detects the time difference between the time ta when the first feature amount A appears and the time tb when the second feature amount B appears as the delay time ΔT.

Subsequently, the processing unit 24 stores the delay time ΔT in the storage unit 22 in step S130. Specifically, the processing unit 24 stores the delay time ΔT in the non-volatile memory of the storage unit 22 so that the delay time ΔT is held in the storage unit 22 even when the ignition switch of the vehicle is turned off.

Here, the pulse wave delay time ΔT is a parameter that differs among individuals. Therefore, the processing unit 24 stores the delay time ΔT in the storage unit 22 in association with the identification information identifying the occupant P. Specific information includes, for example, peculiar information such as a facial image of the occupant P and fingerprint information.

Subsequently, in step S140, the processing unit 24 extracts the signal component caused by the contraction of the ventricle from the received signal. As described above, the contraction amount of the ventricle of the heart H has a strong correlation with the maximum change amount ΔA of the signal intensity of the received signal. Therefore, the processing unit 24 extracts the maximum amount of change ΔA from among the changes in the signal strength of the received signal during the predetermined period as a characteristic amount of change.

Subsequently, in step S150, the processing unit 24 calculates the contraction amount of the ventricle as a physical quantity correlated with the blood pressure. For example, the processing unit 24 refers to a control map or a relational expression that defines the relationship between the maximum variation ΔA and the contraction amount of the ventricle shown in FIG. Calculate the amount of shrinkage. A control map or a relational expression defining the relationship between the maximum amount of change ΔA and the amount of contraction of the ventricle can be obtained, for example, by synchronously acquiring an echo image from which the amount of contraction of the ventricle can be grasped and the signal received by the receiving antenna 13. can be created.

Subsequently, in step S160, the processing unit 24 calculates the blood pressure of the occupant P by correcting the contraction amount of the ventricle by the delay time ΔT. An example of a blood pressure calculation method will be described below.

Blood pressure can be represented by the following formula F1, like Ohm's law, which indicates the relationship between voltage V, current I, and electrical resistance R in an electrical circuit.

Blood pressure = vascular resistance x cardiac output (F1)
The vascular resistance in Equation F1 can be represented by Equation F2 below.

Vascular resistance=α×pulse wave delay time ΔT (F2)
However, α in the formula F2 is a preset constant for converting the delay time ΔT into blood vessel resistance.

Moreover, the cardiac output in the formula F1 can be represented by the following formula F3.

Cardiac output = β x amount of ventricular contraction (F3)
However, β in the formula F3 is a preset constant for converting the contraction amount of the ventricle into the cardiac output.

Formula F1 above can be transformed into Formula F4 below using Formula F2 and Formula F3.

Blood pressure = (α x pulse wave delay time ΔT) x (β x amount of ventricular contraction)
= γ × pulse wave delay time ΔT × amount of ventricular contraction (F4)
However, γ in Expression F4 is a constant set in advance as a parameter unique to the biological information detection device 1 .

The processing unit 24 of the present embodiment substitutes the delay time ΔT stored in the storage unit 22 and the contraction amount of the ventricle calculated in step S150 into the above formula F4 to calculate the blood pressure. That is, the processing unit 24 calculates the blood pressure based on the multiplication result of the amount of contraction of the ventricle, which is a physical quantity correlated with the blood pressure, and the delay time ΔT.

Specifically, the processing unit 24 reads the delay time ΔT corresponding to the occupant P from the storage unit 22 by referring to the identification information for identifying the occupant P. For example, the processing unit 24 identifies the occupant P by comparing the facial image, fingerprint information, and the like of the occupant P acquired from the on-vehicle device with the identification information of the occupant P stored in the storage unit 22, and then handles the occupant P. Then, the delay time ΔT is read out from the storage unit 22 . Then, the processing unit 24 corrects the physical quantity correlated with blood pressure based on the delay time ΔT read from the storage unit 22 .

Subsequently, in step S160, the processing unit 24 outputs the blood pressure calculated in step S150 from the output unit 23 to a device external to the biological information detecting device 1. FIG. The processing unit 24 may output the blood pressure to the driver status monitor DSM that detects the awakening level of the passenger P, for example.

The biological information detection apparatus 1 described above includes a receiving antenna 13 for receiving radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P, and radio waves received by the receiving antenna 13 when the radio waves are radiated from the transmitting antenna 12. and an input unit 21 that acquires a received signal according to. The biological information detecting device 1 includes a pulse wave sensor 15 for detecting the time waveform of the pulse wave of the occupant P, and a processing unit 24 for calculating the blood pressure of the occupant P as biological information. The processing unit 24 calculates a physical quantity correlated with blood pressure from the time waveform of the signal component generated from the received signal due to the movement of the heart H of the occupant P, and corrects the physical quantity based on the time waveform of the pulse wave. to calculate blood pressure. According to this, since the physical quantity correlated with the blood pressure is calculated based on the radio wave transmitted through the target person, it is possible to suppress the physical restraint of the occupant P when the blood pressure is detected. Therefore, it is possible to measure the blood pressure of the occupant P while suppressing hindrance to the occupant P's actions.

(1) The processing unit 24 determines that the second feature B corresponding to the first feature A appears in the time waveform of the pulse wave after the first feature A appears in the time waveform of the signal component of the received signal. The time until the expression occurs is detected as the delay time ΔT. The processing unit 24 calculates the blood pressure by correcting the contraction amount of the ventricle, which is a physical quantity correlated with the blood pressure, based on the delay time ΔT. According to this, if the physical quantity correlated with the blood pressure is corrected by the delay time ΔT that has a correlation with the blood vessel resistance, the blood pressure can reflect the difference in the blood vessel resistance that differs between individuals. can be measured. Moreover, since the delay time ΔT can be detected in the shortest time of one beat, it is possible to shorten the calibration work time for calculating the blood pressure.

(2) Specifically, the processing unit 24 calculates the blood pressure based on the multiplication result of the physical quantity correlated with the blood pressure and the delay time ΔT. As a result, the difference in vascular resistance between individuals can be reflected in the blood pressure by a simple calculation.

(3) The processing unit 24 associates the identification information identifying the occupant P with the delay time ΔT and stores them in the storage unit 22 . When calculating the blood pressure of the occupant P, the delay time ΔT corresponding to the occupant P is read from the storage unit 22 with reference to the specific information for specifying the occupant P, and the blood pressure is calculated based on the delay time ΔT read from the storage unit 22. Correct the correlated physical quantity. According to this, the physical quantity correlated with the blood pressure can be corrected by the delay time ΔT obtained in advance, so that the detection of the delay time ΔT can be prevented from becoming a factor that restricts the body of the occupant P when the blood pressure is detected. .

(Modified example of the first embodiment)
In the first embodiment, the detection of the delay time ΔT and the calculation of the blood pressure are performed in a series of processes. good. For example, the detection of the delay time ΔT may be performed while the vehicle is parked or stopped, and the blood pressure calculation may be performed while the vehicle is running. According to this, since it is not necessary to wear the pulse wave sensor 15 while the vehicle is running, it is possible to suppress the physical restraint of the occupant P while the vehicle is running.

The determination process in step S110 described in the first embodiment may determine, for example, whether or not the elapsed time since the delay time ΔT was stored in the storage unit 22 is within a predetermined period of time. In this determination process, if the determination result is negative, the process proceeds to step S120, and if the determination result is positive, steps S120 and S130 are skipped and the process proceeds to step S140. According to this, since the delay time ΔT is updated as needed, it is possible to measure blood pressure reflecting changes in blood vessel resistance that accompany changes in the body.

(Second embodiment)
Next, a second embodiment will be described with reference to FIG. This embodiment differs from the first embodiment in the device for detecting the time waveform of the pulse wave. In this embodiment, portions different from the first embodiment will be mainly described.

The biological information detection device 1 is configured to detect the time waveform of the pulse wave without contact with the occupant P. As shown in FIG. That is, the biological information detection device 1 is configured by a non-contact sensor that sequentially detects the pulse wave of the occupant P without being attached to the occupant P's body.

Specifically, as shown in FIG. 8, the biological information detection device 1 has a camera 31 for capturing an image of the face of the occupant P inside the vehicle instead of the pulse wave sensor 15 . The camera 31 may be, for example, a dedicated camera or a camera used in the driver status monitor DSM.

In the face image captured by the camera 31, the brightness of pixels in a specific region of the face where blood vessels are present changes according to the pulse. Therefore, the information control unit 20 periodically acquires an image of a range including the face of the occupant P captured by the camera 31, and detects the time waveform of the pulse wave based on the temporal change of the image. Specifically, the information control unit 20 detects the time waveform of the pulse wave by observing the luminance change of pixels in a specific region of the face where the blood vessels are present in the facial image of the occupant P captured by the camera 31 . .

Here, the information control unit 20 of this embodiment includes an image processing unit 25 for extracting information corresponding to the time waveform of the pulse wave from the image captured by the camera 31 . In this embodiment, the image processing unit 25 and the camera 31 constitute a pulse wave detection device for detecting the time waveform of the subject's pulse wave.

Others are the same as in the first embodiment. The biological information detection device 1 of the present embodiment can obtain the same effects as those of the first embodiment, which are provided by the common configuration or the equivalent configuration of the first embodiment.

Moreover, according to this embodiment, the following effects can be obtained.

(1) The biological information detection device 1 is configured to be able to detect the time waveform of the pulse wave without contact with the occupant P. According to this, the blood pressure of the occupant P can be measured without restraining the occupant P's body.

(2) Specifically, the biological information detection device 1 periodically acquires an image of a range including the face of the occupant P captured by the camera 31, and based on the temporal change of the image, the time waveform of the pulse wave to detect Accordingly, the time waveform of the pulse wave of the occupant P can be detected without restraining the occupant P's body. In particular, when the camera 31 is also used for the driver status monitor DSM, there is no need to add a separate dedicated device, so an increase in the number of parts of the biological information detection device 1 can be suppressed.

(Third Embodiment)
Next, a third embodiment will be described with reference to FIGS. 9 to 11. FIG. This embodiment differs from the first and second embodiments in the device for detecting the time waveform of the pulse wave. In this embodiment, portions different from the first embodiment will be mainly described.

As shown in FIG. 9 , the biological information detection device 1 has a sub-antenna 16 instead of the pulse wave sensor 15 . The sub-antenna 16 is arranged to face the transmitting antenna 12 with the passenger P seated in the driver's seat DS therebetween. The sub-antenna 16 is attached to the seat back of the driver's seat DS together with the receiving antenna 13 . The sub-antenna 16 is arranged at a position different from that of the receiving antenna 13 and receives radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P.

The biological information detecting device 1 is provided with a receiving antenna 13 so as to receive radio waves transmitted through the chest region including the heart H of the passenger P's body. Further, the biological information detection device 1 is provided with a sub-antenna 16 so as to receive radio waves transmitted through a part of the body of the occupant P other than the chest part. Specifically, the sub-antenna 16 is arranged at a lumbar support portion of the driver's seat DS that supports the waist of the passenger P so as to receive radio waves transmitted through the abdominal aorta shown in FIG.

Here, blood vessels change their shape according to the pulse. Therefore, in radio waves that pass through blood vessels and their surroundings and reach sub-antenna 116, the dielectric loss that occurs in the electric field intensity changes according to the movement of the blood vessels. Therefore, the intensity of the sub-reception signal received by the sub-antenna 16 contains a component that periodically changes according to the movement of the abdominal aorta. That is, the level of the electrical signal output from the sub-antenna 16 to the receiver 14 when the sub-antenna 16 receives the radio wave from the transmitting antenna 12 contains a component that fluctuates according to the movement of the abdominal aorta.

Therefore, the processing unit 24 of the present embodiment detects the time waveform of the pulse wave based on the time waveform of the signal component of the sub received signal. Specifically, the processing unit 24 detects changes in the signal intensity of the sub-reception signal during a predetermined period as the time waveform of the pulse wave in the abdominal aorta. In this embodiment, the sub-antenna 16 and the processing unit 24 constitute a pulse wave detection device for detecting the time waveform of the subject's pulse wave.

Others are the same as in the first embodiment. The biological information detecting device 1 of the present embodiment can obtain the same effects as those of the first and second embodiments, which are obtained from the same or equivalent configuration as those of the first and second embodiments. .

Moreover, according to this embodiment, the following effects can be obtained.

(1) The biological information detection device 1 is configured to be able to detect the time waveform of the pulse wave without contact with the occupant P. According to this, the blood pressure of the occupant P can be measured without restraining the occupant P's body.

(2) The biological information detection device 1 includes a sub-antenna 16 arranged at a position different from that of the receiving antenna 13 to receive radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P. The input unit 21 acquires a sub received signal corresponding to the radio wave received by the sub antenna 16 when the radio wave is radiated from the transmission antenna 12 . Then, the processing unit 24 detects the time waveform of the pulse wave based on the time waveform of the signal component of the sub received signal. Also by this, the time waveform of the occupant's P pulse wave can be detected without restraining the occupant's P body. In particular, a physical quantity correlated with blood pressure and a time waveform of a pulse wave can be detected using radio waves from the common transmitter 11 and transmission antenna 12 . This greatly contributes to simplification of the biological information detection device 1 .

(3) Specifically, the receiving antenna 13 is arranged so as to receive radio waves transmitted through the chest region including the heart H of the occupant P's body. Further, the sub-antenna 16 is arranged so as to receive radio waves transmitted through a part of the body of the occupant P other than the chest part. According to this, since the blood pressure is calculated based on the radio wave transmitted through the target person without contacting the passenger P, it is possible to suppress the restriction of the target person's body when the blood pressure is detected.

(4) Here, as in the second embodiment and the third embodiment, when the pulse wave detection device is configured with a non-contact sensor, compared to the case of using the pulse wave sensor 15, the pulse acquired as the sensor output Wave time waveform is very small. When the time waveform of the pulse wave is detected while the vehicle is running, it may be difficult to distinguish it from the signal component caused by the vibration of the vehicle.

For this reason, it is preferable to use a portion where the pulse wave signal is stable while the vehicle is stopped such as waiting for a signal or while the vehicle is running. The presence or absence of a portion where the pulse wave signal is stable can be determined, for example, based on the peak intensity and SN ratio in the frequency characteristics of a certain section as shown in FIG. 11 . For example, when a single peak intensity is formed in the frequency characteristics of a certain interval, it can be determined that there is a portion where the pulse wave signal is stable. Note that the frequency characteristics shown in FIG. 11 can be obtained by Fourier transforming the time waveform of the received signal. Also, the SN ratio is a value obtained by dividing the peak intensity by the average intensity of other frequencies.

(Modified example of the third embodiment)
In the third embodiment, an example has been described in which the sub-antenna 16 is arranged in the lumbar support portion of the driver's seat DS that supports the lumbar portion of the occupant P so as to receive radio waves transmitted through the abdominal aorta. The arrangement of 16 is not limited to this. Also, the sub-antenna 16 may be arranged on the headrest so as to receive radio waves transmitted through the carotid artery, for example. Further, the sub-antenna 16 may be arranged on a seat cushion forming a seat surface in the driver's seat DS so as to receive radio waves transmitted through the popliteal artery.

(Other embodiments)
Although representative embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be modified in various ways, for example, as follows.

In the above-described embodiment, the delay time ΔT is detected as the time from when the first feature amount A appears in the time waveform of the signal component of the received signal to when the second feature amount B appears in the time waveform of the pulse wave. but not limited to this. The delay time ΔT may be detected by, for example, a control map or a relational expression that pre-associates the time waveform of the signal component of the received signal, the time waveform of the pulse wave, and the delay time ΔT.

In the above-described embodiment, the blood pressure is calculated based on the multiplication result of the physical quantity correlated with the blood pressure and the delay time ΔT, but the present invention is not limited to this. The blood pressure may be calculated by, for example, a physical quantity correlated with the blood pressure, the delay time ΔT, and a control map or relational expression that pre-associates the blood pressure.

In the above-described embodiment, the processing unit 24 automatically reads the delay time ΔT corresponding to the occupant P from the storage unit 22 when calculating the blood pressure of the occupant P, but the present invention is not limited to this. For example, the delay time ΔT selected by the occupant P as information on his/her pulse wave may be read from the storage unit 22 .

In the above-described embodiment, an example in which the delay time ΔT is detected while the vehicle is parked or stopped, or while the vehicle is running has been described. The time ΔT may be detected.

The pulse wave detection device is not limited to those described in the first to third embodiments. For example, a piezoelectric sensor, a millimeter wave radar, or the like is used as a displacement sensor to detect a pulse wave from the body surface displacement due to the pulse. may be configured. Since the pulse wave detection device is a device for determining the delay time ΔT, it can be brought into the vehicle when determining the delay time ΔT, and does not need to be permanently installed in the vehicle.

In the above-described embodiment, the receiving antenna 13 is attached to the seat S, but the receiving antenna 13 may be attached to something other than the seat S.

In the above-described embodiment, the transmitting antenna 12 and the receiving antenna 13 are arranged in the front and rear of the vehicle with the occupant P interposed therebetween, but the biological information detection device 1 is not limited to this. The biological information detection device 1 may be arranged, for example, so that the transmitting antenna 12 and the receiving antenna 13 are arranged on the left and right sides of the vehicle with the occupant P interposed therebetween. The biometric information detection device 1 may be configured to calculate biometric information of not only the driver but also other occupants P. Further, the biological information detection device 1 is used not only for calculating the biological information of the passenger P of the vehicle, but also for calculating the biological information of a person outside the vehicle (for example, inside a building). good too.

In the above-described embodiments, it goes without saying that the elements that make up the embodiments are not necessarily essential unless explicitly stated as essential or clearly considered essential in principle.

In the above-described embodiments, when numerical values such as the number, numerical value, amount, range, etc. of the constituent elements of the embodiment are mentioned, when it is explicitly stated that they are essential, and in principle they are clearly limited to a specific number It is not limited to that particular number, unless otherwise specified.

In the above-described embodiments, when referring to the shape, positional relationship, etc. of components, etc., the shape, positional relationship, etc., unless otherwise specified or limited in principle to a specific shape, positional relationship, etc. etc. is not limited.

In the above-described embodiments, when it is described that the vehicle's external environment information is obtained from a sensor, it is also possible to eliminate the sensor and receive the external environment information from a server or cloud outside the vehicle. Alternatively, it is also possible to eliminate the sensor, acquire related information related to the external environment information from a server or cloud outside the vehicle, and estimate the external environment information from the acquired related information.

The controller and techniques of the present disclosure are implemented on a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by the computer program. good too. The controller and techniques of the present disclosure may be implemented in a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. The control unit and method of the present disclosure is a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. It may be implemented on one or more dedicated computers. The computer program may also be stored as computer-executable instructions on a computer-readable non-transitional tangible recording medium.

1 biological information detection device 12 transmission antenna 13 reception antenna 14 receiver 15 pulse wave sensor (pulse wave detection device)
21 input unit (signal acquisition unit)
24 processing unit (computing unit)

Claims (8)

A biological information detection device for detecting biological information of a subject,
a receiving antenna (13) for receiving radio waves radiated from the transmitting antenna (12) and transmitted through the subject;
a signal acquisition unit (21) for acquiring a received signal corresponding to the radio wave received by the receiving antenna when the radio wave is radiated from the transmitting antenna;
a pulse wave detection device (15, 16, 24, 25, 30) for detecting the time waveform of the subject's pulse wave;
A calculation unit (24) that calculates the subject's blood pressure as the biological information,
The calculation unit calculates a physical quantity correlated with the blood pressure from a time waveform of a signal component generated from the received signal due to the movement of the heart of the subject, and corrects the physical quantity based on the time waveform of the pulse wave. a biological information detection device that calculates the blood pressure by The calculation unit is
delaying the pulse wave by the time from when a first feature amount appears in the time waveform of the signal component to when a second feature amount corresponding to the first feature amount appears in the time waveform of the pulse wave; detect as time,
The biological information detection device according to claim 1, wherein said blood pressure is calculated by correcting said physical quantity based on said delay time. 3. The biological information detection device according to claim 2, wherein said calculation unit calculates said blood pressure based on a multiplication result of said physical quantity and said delay time. The calculation unit associates the specific information specifying the subject with the delay time and stores the information in a storage unit (22);
When calculating the blood pressure of the subject, the delay time corresponding to the subject is read from the storage unit with reference to the specific information, and the physical quantity is calculated based on the delay time read from the storage unit. 4. The biological information detection device according to claim 2, wherein the correction is performed. 5. The biological information detection device according to claim 1, wherein said pulse wave detection device detects a temporal waveform of said pulse wave without contact with said subject. The pulse wave detection device periodically acquires an image of a range including the face of the subject captured by a camera (31), and detects the temporal waveform of the pulse wave based on the temporal change of the image. The biological information detecting device according to any one of claims 1 to 5. The pulse wave detecting device includes a sub-antenna (16) arranged at a position different from the receiving antenna and receiving radio waves radiated from the transmitting antenna and transmitted through the subject,
The signal acquisition unit acquires, as a sub-reception signal, a signal corresponding to the radio wave received by the sub-antenna when the radio wave is radiated from the transmission antenna,
6. The biological information detecting device according to claim 1, wherein said computing unit detects the time waveform of said pulse wave based on the time waveform of said sub received signal. The receiving antenna is arranged to receive radio waves transmitted through a chest region including the heart of the subject's body,
8. The biological information detecting device according to claim 7, wherein said sub-antenna is arranged so as to receive radio waves transmitted through a part of said subject's body other than said chest part.

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