JP2016168177A - Biological information detector and seat with backrest - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological information detector and a seat with a backrest capable of accurately detecting biological information on a person to be measured while reducing a burden on the person to be measured with no contact or no constraint.SOLUTION: A biological information detector includes first blood flow measurement means 2 provided to a seating face of a seat for measuring a blood flow state of the popliteal artery of a person M to be measured sitting on the seat, second blood flow measurement means 3 provided to a back surface part of the seat for measuring a blood flow state of the thoracic aorta of the person to be measured, and blood pressure calculation means for obtaining a pulse wave propagation speed and an arteriosclerotic level from blood flow data measured by the first blood flow measurement means 2 and blood flow data measured by the second blood flow measurement means 3, and calculating blood pressures of the popliteal artery and the thoracic aorta of the person to be measured based on the pulse wave propagation speed and the arteriosclerotic level.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a biological information detection device and a seat with a backrest that detect biological information of a measurement subject.

  Generally, when a vehicle driver's health condition deteriorates, it may adversely affect the driving of the vehicle. Therefore, it is desirable to detect the deterioration of the health condition in advance and take some measures. For this reason, a health management system that can continuously monitor the health state of the driver while driving has been proposed.

  For example, the driver's arm can be gripped (see Patent Document 1), or a cuff can be wrapped around or attached to the driver's arm or fingertip (see Patent Document 2). Biometric information was detected.

  However, wrapping the cuff was cumbersome for the driver and the driver was under cuff pressure. Further, gripping the electrode provided on the steering wheel restricts the driver's posture.

  Thus, conventionally, there has been a problem that the burden on the vehicle driver is large when detecting the biological information of the vehicle driver.

  In order to alleviate such a burden problem for the vehicle driver, a method of diagnosing by irradiating microwaves in a non-contact manner and measuring heartbeat / respiration has been proposed (for example, see Patent Documents 3 and 4). However, even when using a non-contact type biometric information detection method as described in Patent Documents 3 and 4, it is necessary to attach a sensor or the like to the vehicle driver, and there is a problem that the burden is large.

JP 2007-290504 A International Publication No. 2007/46283 JP 2008-99849 A JP 2014-105 A

  By the way, the health management of vehicle drivers such as taxis and buses is indispensable, and the frequency of getting on and off is relatively high for crew, so blood pressure values should be constantly monitored without restraining the limbs of the vehicle driver. Is desirable.

  The present invention has been made in view of the above-described conventional situation, and detects biological information of a measurement subject with high accuracy while reducing a burden of non-contact and non-binding to the measurement subject. It is an object of the present invention to provide a living body information detecting apparatus and a seat with a backrest that can be used.

  A biological information detection apparatus according to an aspect of the present invention includes a first blood flow measurement unit that is provided on a seating surface portion of a sheet and measures a blood flow state of a popliteal artery of a measurement subject seated on the sheet; A second blood flow measuring means for measuring a blood flow state of the thoracic aorta of the measurement subject; blood flow data measured by the first blood flow measuring means; and the second blood flow measuring means. The pulse wave velocity and the degree of arteriosclerosis are obtained from the blood flow data measured by the above, and the blood pressure of the popliteal artery and the thoracic aorta of the subject is calculated based on the pulse wave velocity and the degree of arteriosclerosis, respectively. Blood pressure calculating means.

  The biological information detection apparatus according to an aspect of the present invention includes a database that stores blood flow data obtained from the first blood flow measurement unit and the second blood flow measurement unit, and the blood pressure calculation unit includes a predetermined period of time. Based on the blood flow data accumulated in the database, blood pressure of the popliteal artery and the thoracic aorta is calculated in time series, and the health condition of the measurement subject is monitored.

  The biological information detection apparatus according to an aspect of the present invention includes a cardiopulmonary function measuring unit that is provided on a back surface portion of the seat and measures a heart rate and a respiratory rate of the subject, and the blood pressure calculating unit includes the heart rate And correcting the blood pressure of the popliteal artery and the thoracic aorta based on the respiratory rate so that the time difference between the pressure waveforms of the popliteal artery and the thoracic aorta of the subject is substantially constant. And

  In the biological information detecting apparatus according to one aspect of the present invention, the database stores a heart rate and a respiratory rate obtained from the cardiopulmonary function measuring unit, and the blood pressure calculating unit accumulates the database in the database over a predetermined period. The blood pressure of the popliteal artery and the thoracic aorta is corrected based on the heart rate and the respiratory rate, respectively.

  A seat with a backrest according to an aspect of the present invention includes the biological information detection device.

  ADVANTAGE OF THE INVENTION According to this invention, the biological information of a to-be-measured person can be detected with high precision, reducing the burden which is non-contact and non-restraining to the to-be-measured person.

It is a block block diagram of the biological information detection apparatus which concerns on embodiment of this invention. It is an internal block diagram of a 1st blood flow measurement sensor and a 2nd blood flow measurement sensor. It is a longitudinal cross-sectional view which expands and shows the attachment structure of a detection unit. It is a figure for demonstrating the principle of a blood-flow measurement method. It is a figure which shows the relationship between the light absorption state at the time of changing the wavelength of a laser beam, and the oxygen saturation of blood. It is a wave form diagram which shows the waveform of the detection signal of each optical sensor unit. It is a flowchart for demonstrating the PWV control process based on the detection signal from each optical sensor unit. It is a block diagram which shows the internal structure of a cardiopulmonary function sensor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of biological information detection apparatus]
FIG. 1 is a block configuration diagram of a biological information detection apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the biological information detection apparatus 1 includes a first blood flow measurement sensor 2, a second blood flow measurement sensor 3, a cardiopulmonary function sensor 4, and an external unit 5 that are attached to the vehicle seat S. The detection results from the sensors 2 to 4 are transmitted to the external unit 5 wirelessly.

  The first blood flow measurement sensor 2 and the second blood flow measurement sensor 3 each measure the blood flow at a position facing the skin surface of the measurement target region of the measurement subject. The first blood flow measurement sensor 2 and the second blood flow measurement sensor 3 have the same configuration, and each includes a detection unit 12 (FIG. 2) having an optical sensor that measures the blood flow flowing in the blood vessel in a non-contact manner. ing.

  In the present embodiment, the first blood flow measurement sensor 2 is installed on the seat surface of the vehicle seat S, and near infrared light toward the buttocks or thighs of the measurement subject M seated on the vehicle seat S. , Receiving the reflected light, and detecting displacement (blood vessel characteristics) of the blood vessel and the tissue around the blood vessel due to the blood flow of the popliteal artery. The second blood flow measurement sensor 3 is installed on the back surface of the vehicle seat S, emits near-infrared light toward the back of the measurement subject M seated on the vehicle seat S, and receives reflected light. Detect vascular characteristics of the thoracic aorta.

  The cardiopulmonary function sensor 4 is installed on the back surface of the vehicle seat S, irradiates microwaves toward the back of the measurement subject M seated on the vehicle seat S, receives reflected waves, and receives the heart rate and the respiratory rate. Is detected.

  The external unit 5 includes a wireless communication device 6 that receives measurement data that is a result of each of the first blood flow measurement sensor 2, the second blood flow measurement sensor 3, and the cardiopulmonary function sensor 4, and a database that stores the measurement data. 7, a display device 8 that displays various processing results based on the respective measurement data, and a control device 9 that controls all these devices.

[Internal configuration of first blood flow measurement sensor 2 and second blood flow measurement sensor 3]
Here, the configuration of the first blood flow measurement sensor 2 (second blood flow measurement sensor 3) will be described with reference to FIG. In the first blood flow measurement sensor 2 (second blood flow measurement sensor 3), a flexible substrate 11 is held on one surface of a thin resin sheet-like board 10. On the flexible substrate 11, a detection unit 12 and A measurement control unit 13, a wireless communication device 14, and a rechargeable battery 15 are mounted, and these are covered and protected by a case 16 made of resin or the like.

  In the first blood flow measurement sensor 2 (second blood flow measurement sensor 3), the other surface of the sheet-like board 10 is a measurement surface that is opposed (non-contacted and close to the measurement area), and is in the sheet form. By appropriately facing the measurement surface on the other side of the board to the skin surface of the measurement region, the detection unit 12 is used to measure the displacement (blood vessel characteristics) of the blood vessel and the tissue around the blood vessel due to blood flow in the measurement region. Can be performed without contact.

  Further, in the first blood flow measurement sensor 2 (second blood flow measurement sensor 3), the measurement control unit 13 supplies the current from the battery 15 to the light emitting unit of the detection unit 12, which will be described later, and emits light. The light receiving signal from the light receiving unit that receives the light propagating through the light is read. The wireless communication device 14 performs wireless communication with the control device 9 of the external unit 5 (FIG. 1), and wirelessly transmits a light reception signal from the light receiving unit to the control device.

  Since the first blood flow measurement sensor 2 (second blood flow measurement sensor 3) is a wireless unit capable of wireless communication with the external unit 5, the first blood flow measurement sensor 2 can freely move to the measurement region. In addition, the rechargeable battery 15 of the first blood flow measurement sensor 2 (second blood flow measurement sensor 3) is appropriately charged when it is not used without blood flow measurement.

[Internal configuration of detection unit 12]
Here, the internal configuration of the detection unit in the first blood flow measurement sensor 2 and the second blood flow measurement sensor 3 will be described. FIG. 3 is an enlarged longitudinal sectional view showing the mounting structure of the detection unit 12.

  As shown in FIG. 3, the detection unit 12 includes three optical sensor units 21 </ b> A to 21 </ b> C arranged in a line inside a flexible wiring board 20 formed in a dome shape.

  Each of the optical sensor units 21A, 21B, and 21C is held such that when the person to be measured is seated on the vehicle seat S, the light emitting surface and the light receiving surface at the tip portion are close to (or in contact with) the skin surface of the person to be measured. . Each of the optical sensor units 21A, 21B, and 21C has the same configuration, and the same reference numerals are given to the same portions.

  The optical sensor unit 21 </ b> A includes a light emitting unit 22, a light receiving unit 23, and an optical path separating member 24. The light emitting unit 22 is composed of a laser diode that irradiates the skin surface with laser light (emitted light) A. The light receiving unit 23 includes a light receiving element that outputs an electrical signal corresponding to the amount of transmitted light. The optical path separation member 24 is formed of, for example, a holographic optical element (HOE) using a hologram, and the refractive index with respect to the laser light A irradiated from the light emitting unit 22 toward the measurement region, and the measurement region The refractive indexes of the incident lights B and C that pass through the light and travel to the light receiving unit are different.

  A housing 25 formed in a cylindrical shape is fitted to the outer periphery of the optical path separating member 24. The light emitting unit 22 and the light receiving unit 23 are mounted on the lower surface side of the flexible wiring board 20 on the upper surface side. A wiring pattern connected to the measurement control unit 13 (FIG. 2) is formed on the flexible wiring board 20, and the light emitting unit 22 and the light receiving unit 23 are arranged at positions corresponding to the respective optical sensor units 21A to 21C. Are electrically connected by soldering or the like. The flexible wiring board 20 is configured to bend according to the surface shape when the tips of the optical sensor units 21 </ b> A to 21 </ b> C come into contact with the measurement target region.

  When blood flow measurement is performed, the measurement control unit 13 causes the laser light A to be emitted from the light emitting unit 22 of the optical sensor unit 21A. At this time, the laser light emitted from the light emitting unit 22 is output at a wavelength λ (λ≈805 nm) that is not affected by the oxygen saturation.

  In addition, each of the optical sensor units 21A to 21C is held in a state in which the tip (end surface of the optical path separation member 24) is in contact with the measurement target area of the measurement subject. The laser light A emitted from the light emitting unit 22 passes through the optical path separating member 24 and is incident on the skin surface SK from the vertical direction. Inside the skin surface SK (inside the body), the laser light A travels toward the center, and the laser light A propagates toward the periphery along the skin surface SK with the incident position as a base point. The light propagation path LR of the laser light A is formed in an arc shape when viewed from the side, passes through the blood vessel BV, and returns to the skin surface SK.

  Thus, the light that has passed through the light propagation path LR reaches the photosensor units 21B and 21C on the light receiving side while changing the amount of transmitted light according to the amount or density of red blood cells contained in the blood flowing through the blood vessel BV. Further, since the amount of transmitted light of the laser light A gradually decreases in the process of propagating inside the human body, the light receiving level of the light receiving unit 23 decreases in proportion to the distance as the laser light A moves away from the base point. Accordingly, the amount of transmitted light varies depending on the distance from the incident position of the laser beam A.

  In FIG. 3, when the optical sensor unit 21A located at the left end is a light emitting side base point, the optical sensor unit 21A itself, the right adjacent optical sensor unit 21B, and the right adjacent optical sensor unit 21C are the light receiving side. This is the base point (measurement point).

  The optical path separating member 24 is formed to change the density distribution of a transparent acrylic resin, for example, so that the laser light A travels straight and guides the incident lights B and C to the light receiving unit. The optical path separation member 24 includes an emission side transmission region 30 that transmits the laser light A emitted from the light emitting unit 22 from the proximal end side (upper surface side in FIG. 3) to the distal end side (lower surface side in FIG. 3), Between the incident side transmission region 31 that transmits the light propagating from the front end side (lower surface side in FIG. 3) to the proximal side (upper surface side in FIG. 3), and between the emission side transmission region 30 and the incident side transmission region 31 And a formed refraction region 32.

  The refractive region 32 transmits the laser light A, but has a property of reflecting light (incident light B and C) that has passed through the bloodstream. The refracting region 32 is formed, for example, by changing the density of the acrylic resin, providing a metal thin film in this region, or dispersing metal fine particles. As a result, all the light incident from the tip of the optical path separating member 24 is collected on the light receiving unit 23.

[Principle of blood flow measurement method]
FIG. 4 is a diagram for explaining the principle of the blood flow measurement method. As shown in FIG. 4, when laser light A is irradiated to the blood in the blood vessel BV from the outside, the laser light A that has entered the blood layer BR is reflected and scattered light components by normal red blood cells RC, and reflected by the attached thrombus. It travels through the blood as light of both components of the scattered light component.

  The effect that light receives in the process of passing through the blood layer changes with the state of the blood, so various amounts of blood can be obtained by continuously measuring the amount of transmitted light (or the amount of reflected light) and observing changes in the amount of light. It becomes possible to observe the change of the property of.

  When the activity of the subject increases, the amount of oxygen consumed in the body increases, so that the state of blood flow caused by hematocrit of red blood cells carrying oxygen and oxygen saturation of blood appears as a change in light quantity.

  Here, changes such as hematocrit (Hct: volume ratio of erythrocytes per unit volume, that is, the volume concentration of erythrocytes per unit volume, also expressed as Ht) are also factors related to changes in hemoglobin density. Yes, it affects the amount of light change. The basic principle in this embodiment is that the state of the blood flow is measured by the change in the optical path and the amount of transmitted light due to the blood flow using the laser light A in this way.

Further, the principle configuration will be described. The optical properties of blood are determined by blood cell components (especially hemoglobin inside the cells of red blood cells). In addition, erythrocytes have a property that hemoglobin easily binds to oxygen, and thus play a role of transporting oxygen. The oxygen saturation of blood is a numerical value representing what percentage of hemoglobin in the blood is bound to oxygen. The oxygen saturation is correlated with the oxygen partial pressure (PaO ₂ ) in arterial blood, and is an important index of respiratory function (gas exchange).

  It is known that when the oxygen partial pressure is high, the oxygen saturation increases, and when the oxygen saturation varies, the amount of light transmitted through the blood also varies. Therefore, when blood flow is measured, more accurate measurement is possible by removing the influence of oxygen saturation.

Factors affecting the oxygen partial pressure (PaO ₂ ) include alveolar ventilation, and also the environment such as atmospheric pressure and inhaled oxygen concentration (FiO ₂ ), ventilation / blood flow ratio and gas diffusion. There are gas exchanges in the alveoli such as performance and short circuit rate.

  The control device 9 of the external unit 5 executes a PWV control process, which will be described later, based on the measurement data corresponding to the transmitted light amount (light intensity) generated by the light receiving unit 23 of the optical sensor units 21A to 21C, and the blood flow state Is detected.

  The laser beam A of the light emitting unit 22 is irradiated as pulsed light or continuous light that is intermittently irradiated at a predetermined time interval (for example, 10 Hz to 1 MHz). In this case, when using pulsed light, a point reduction frequency, which is a frequency at which the pulse light is reduced, is determined according to the blood flow velocity, and continuously or at a measurement sampling frequency that is at least twice the point reduction frequency. measure. When continuous light is used, the measurement sampling frequency is determined according to the blood flow velocity and measured.

Hemoglobin (Hb) in the blood undergoes a chemical reaction with oxygen in the lungs by breathing and becomes HbO ₂ , and oxygen is taken into the blood. However, the degree to which oxygen is taken into the blood depending on the state of breathing, etc. (Oxygen saturation) is slightly different. That is, in this embodiment, when light is irradiated to blood, a phenomenon is found in which the light absorption rate changes depending on the oxygen saturation, and this phenomenon becomes a disturbance factor in the measurement of blood flow by the laser light A. It becomes possible to remove the influence of oxygen saturation.

FIG. 5 is a graph showing the relationship between the wavelength of laser light and the light absorption state when the oxygen saturation level of blood is changed. In the body, hemoglobin contained in erythrocytes is divided into oxygenated hemoglobin (HbO ₂ : graph II (shown by a broken line)) combined with oxygen and non-oxidized hemoglobin (Hb: graph I (shown by a solid line)). In these two states, the light absorption rate with respect to light is greatly different. For example, blood containing plenty of oxygen is vivid as fresh blood. On the other hand, venous blood is darker than it is because it has released oxygen. These light absorptance states change in a wide wavelength region of light as shown in graphs I and II of FIG.

  By selecting a specific wavelength from the graphs I and II in FIG. 5, even if the oxygen saturation of hemoglobin in red blood cells varies greatly due to oxygen metabolism in the living body, the light absorption rate is not affected and blood It can be seen that blood flow can be measured by irradiating with light.

  Regardless of the oxygen saturation of hemoglobin in red blood cells, the light absorption rate is small in a certain wavelength region. As a result, whether or not light easily passes through the blood layer is determined by the wavelength λ. Therefore, if light in a predetermined wavelength region (for example, near λ = 800 nm to 1300 nm) is used, blood flow can be measured while suppressing the influence of oxygen saturation.

  Therefore, the wavelength region of the laser beam A uses approximately 1500 nm to 1500 nm, whereby the light absorption rate of hemoglobin (Hb) is sufficiently low in practical use and includes an isosbestic point Z in this region. Utilizing the above measurement points, it can be regarded as an isosbestic point in the calculation. That is, it is possible to make the specification not affected by the oxygen saturation.

  In other wavelength regions, for example, less than λ = 600 nm, the light absorptance is increased and the S / N is decreased. At wavelengths exceeding λ = 1500 nm, the light receiving sensitivity of the light receiving unit is not sufficient and is not sufficient in blood. Disturbances such as other components influence and accurate measurement cannot be performed.

  For this reason, in the present embodiment, a light emitting element made of a wavelength tunable semiconductor laser is used for the light emitting unit 22, and the wavelength of the laser light A emitted from the light emitting unit 22 is λ1 = the equal absorption point Z in the graphs I and II = Two types are set: 805 nm (first light) and a wavelength λ2 = 680 nm (second light) having the lowest light absorptance in the graph I.

  Here, a method for detecting the red blood cell concentrations R, Rp, and Rpw based on the amount of transmitted light when the laser light A receives light propagated through the light propagation path LR (see FIG. 3) will be described.

  The calculation formula (1) of the red blood cell concentration R when the one-point one-wavelength method performed by the conventional measurement method is used can be expressed as the following formula.

R = log 10 (I _in / I _out ) = f (I _in , L, Ht) (1)

In the method of the formula (1), the red blood cell concentration is the incident transmitted light amount I _in of the laser light A emitted from the light emitting unit 22, the distance (optical path length) L between the light emitting unit 22 and the light receiving unit 23, and the hematocrit described above. It becomes a function with (Ht). Therefore, when the red blood cell concentration is determined by the method of formula (1), the red blood cell concentration varies depending on three factors, and it is difficult to accurately measure the red blood cell concentration.

  The calculation formula (2) of the red blood cell concentration Rp when the two-point one-wavelength method according to the present embodiment is used can be expressed as the following formula.

Rp = log 10 {I _out / (I _out −ΔI _out )} = Φ (ΔL, Ht) (2)

  In this method (2), since the light is received at two points (light receiving parts of the optical sensor units 21B and 21C) having different distances from the laser light A as shown in FIG. 3, the red blood cell concentration is the distance between the two light receiving parts 23. It becomes a function of ΔL and the aforementioned hematocrit (Ht). Therefore, when the red blood cell concentration is obtained by the method of equation (2), since the distance ΔL between the light receiving parts 23 is known in advance among the two factors, the red blood cell concentration is measured as a value using the hematocrit (Ht) as a coefficient. . Therefore, in this calculation method, the red blood cell concentration can be accurately measured as a measurement value corresponding to hematocrit (Ht).

  Furthermore, the calculation formula (3) of the red blood cell concentration Rpw when the two-point two-wavelength method according to the modification of the present embodiment is used can be expressed as the following formula.

_{Rpw = [log10 {I out /} (I out -ΔI out)} λ1] / [log10 {I out / (I out -ΔI out)} λ2] = ξ (Ht) ··· (3)

  In the method of formula (3), the wavelength of the laser light A emitted from the light emitting unit is set to different λ1 and λ2 (in this embodiment, λ1 = 805 nm and λ2 = 680 nm), so that the red blood cell concentration is hematocritized. It is measured as a function of only (Ht). Therefore, according to this calculation method, it is possible to accurately measure the red blood cell concentration as a measurement value according to hematocrit (Ht).

  In the light propagation, the light propagation path LR becomes longer and the light transmittance decreases as the distance from the base point irradiated with the laser light A increases in the radial direction, so that the light transmittance decreases. The received light level (transmitted light amount) of the optical sensor unit 21B is strong, and then, the received light level (transmitted light amount) of the optical sensor unit 50C provided adjacent to it by a predetermined distance is higher than the received light level of the optical sensor unit 21B. Weakly detected. Further, the light receiving portion of the light-emitting side optical sensor unit 21A also receives light from the skin surface. In the control device 9 of the external unit 5, detection signals corresponding to the light intensities received by the plurality of optical sensor units 21 </ b> A to 21 </ b> C are stored in the database 7 in time series.

In addition, the detection signal output from each of the optical sensor units 21A to 21C (the signal corresponding to the amount of transmitted light received) is set to I _out in the above-described equation (2) or (3), whereby the red blood cell concentration is hematocrit (Ht ) Can be accurately measured as a measured value (a value that is not affected by oxygen saturation).

  FIG. 6 is a waveform diagram showing waveforms of detection signals of the respective optical sensor units 21A to 21C. As shown in FIG. 6, by comparing the light receiving portion detection signal waveforms (A) to (C) based on the emission time Ts of the laser light A emitted from the light emitting portion 22, the emission time Ts and the light receiving portion detection are compared. Phase differences T1 to T3 from the lowest values of signals (A) to (C) are obtained.

  The phase differences T1 to T3 have a relationship of T1 <T2 <T3 and change according to the pulse wave propagation velocity. Approximate values Δt1 and Δt2 of PWV are obtained from the phase differences of the detection signals of the respective optical sensor units 21A to 21C, T2−T1 = Δt1, and T3−T1 = Δt2.

[PWV control processing by control device]
Here, a PWV (Pulse Wave Velocity) control process executed by the control device 9 of the external unit 5 based on the above principle will be described.

  FIG. 7 is a flowchart for explaining PWV control processing based on detection signals from the respective optical sensor units 21A to 21C. In FIG. 7, the control apparatus 9 reads each measurement data (measurement data by the transmitted light amount according to a blood flow) stored in the database 7 by S1. Subsequently, the process proceeds to S2, and the red blood cell concentration Rp or Rpw is calculated using each measurement data and the arithmetic expression (2) or (3) described above.

  In the next S3, the change in the displacement state of the blood vessel and the tissue around the blood vessel due to the blood flow is obtained from the change in the red blood cell concentration at each measurement position, and the change in the displacement state of the blood vessel and the tissue around the blood vessel is determined for each measurement position. Deriving blood flow velocity.

  Then, it progresses to S4 and compares the detection signal waveform (or waveform of the inner wall displacement data corresponding to a blood flow change) output from each optical sensor unit 21A-21C.

  In S5, as shown in FIG. 6, the PWV values Δt1 and Δt2 are calculated from the phase difference of the detection signal waveforms of the detection signals (A) to (C), T2−T1 = Δt1, and T3−T1 = Δt2. . Further, the pulse wave propagation velocity based on the value of PWV is calculated, and the blood vessel characteristics (the elasticity ratio of the blood vessel, the plaque amount in the blood vessel, the arteriosclerosis ratio) corresponding to the pulse wave propagation velocity are calculated in the database 7. The degree of arteriosclerosis of the blood vessel in the measurement area is derived.

  Subsequently, in S6, the pulse wave propagation speed based on the value of PWV and the arteriosclerosis degree of the blood vessel are stored in the database, and the pulse wave propagation speed based on the value of PWV and the arteriosclerosis degree of the blood vessel are displayed on the display device 8. . In addition, the phase difference of the measurement data of both the first blood flow measurement sensor and the second blood flow measurement sensor is obtained, and this is stored as a calculation result.

  Subsequently, the process proceeds to S7, and it is checked whether the calculation of PWV and the detection of the pulse wave propagation speed have been completed for all measurement data (for example, all data for one week) of each of the optical sensor units 21A to 21C. In S27, when the calculation of PWV and the detection of the pulse wave velocity for all measurement data are not completed, the process returns to S21 and the processes after S21 are repeated.

  In S7, when the calculation of PWV and the detection of the pulse wave velocity are completed for all measurement data, the process proceeds to S8, and the PWV measurement result and pulse of all measurement data input from the control device 9 of the external unit 5 are processed. The wave propagation velocity is displayed on the display screen of the display device 8. As a result, it becomes possible for the measurement subject to check the PWV measurement result and the pulse wave propagation speed based on all measurement data measured in the life of a predetermined period (for example, one week).

[Blood pressure calculation method]
As described above, the control device 9 of the external unit 5 determines the pulse wave propagation speed and the vascular characteristics of the measurement subject's popliteal artery and thoracic aorta (the displacement state of the blood vessel and the tissue around the blood vessel due to blood flow). The degree of arteriosclerosis can be determined.

  And the control apparatus 9 can obtain | require a to-be-measured person's blood pressure (arterial pressure) by a calculation based on a pulse-wave propagation speed and arteriosclerosis degree.

  That is, it is known that if the pulse wave velocity is c and the arterial pressure is P, the relational expression is established as shown below using the degree of arteriosclerosis. This shows that the pulse wave propagation speed depends on the hardness of the blood vessel and also on the blood pressure. In the following formula, ρ is a blood density, and β is a constant (stiffness parameter) representing the degree of blood vessel hardness.

  As described above, the control device 9 can calculate the blood pressure (arterial pressure P) of the popliteal artery and the thoracic aorta of the measurement subject of the measurement subject from this mathematical expression.

[Configuration of cardiopulmonary function sensor]
As shown in FIG. 8, the cardiopulmonary function sensor 4 includes a local transmitter 40, a transmission antenna 41, a reception antenna 42, a mixer 43, an amplifier 44, an A / D converter 45, an arithmetic control unit 46, and a wireless communication device 47. I have.

  The local oscillator 40 generates a microwave. The microwave generated by the local transmitter 40 is radiated from the transmission antenna 41, reflected by the human body (object), and received by the reception antenna 42. Here, the human body includes not only the whole body but also organs such as the heart and lungs. The microwave generated by the living part oscillator 40 preferably has a frequency of about 10 MHz. Thereby, the microwave radiated | emitted from the transmission antenna 41 approachs a human body, and it becomes easy to acquire a reflected wave from organs, such as a heart and a lung.

  The reflected wave received by the receiving antenna 42 is mixed by the mixer 43 with the signal generated by the local oscillator 40. That is, homodyne detection is performed in which the microwave (local signal) generated by the local oscillator 40 and the reflected wave (received signal) are mixed to detect the Doppler signal. The living part oscillator 40, the transmission antenna 41, the reception antenna 42, and the mixer 43 are Doppler sensors, and the mixer 43 functions as a detector.

  When there is no movement in the human body, the frequency of the microwave generated by the local oscillator 40 and the frequency of the microwave reflected from the human body are the same frequency, so the output of the mixer 43 does not include an AC component. That is, the output of the mixer 43 is 0 Hz (direct current).

  On the other hand, when the human body approaches or separates from the transmitting antenna 41 and the receiving antenna 42, the reflected wave component changes due to the Doppler effect, and thus a difference signal appears at the output of the mixer 43. This difference signal includes components corresponding to heart motion (heartbeat) and lung motion (breathing). The output of the mixer 43 is amplified by an amplifier 44 and converted from analog to digital by an A / D converter 45.

  The arithmetic control unit 46 performs a fast Fourier transform on the output signal of the A / D converter 45 and calculates a heart rate and a respiration rate for the converted signal. Since the heart and lungs behave differently, they can be handled separately by filtering.

  For example, the arithmetic control unit 46 performs a filter process on the signal after the fast Fourier transform using a filter whose pass band is the frequency band of the heart rate, and the frequency having the maximum amplitude in the frequency distribution after the filter process. From this, the heart rate is calculated.

  Further, for example, the arithmetic control unit 46 performs a filtering process on the signal after the fast Fourier transform using a filter whose pass band is the frequency band of the respiration rate, and the amplitude is maximum in the frequency distribution after the filtering process. The respiration rate is calculated from the following frequency.

  The arithmetic control unit 46 converts the heart rate and the respiratory rate into wireless signals by the wireless communication device 47 and transmits them to the control device 9 of the external unit 5. The control device 9 of the external unit 5 stores the heart rate and the respiration rate in the database 7.

  The database 7 stores the heart rate and the respiratory rate so that the past history can be grasped as appropriate. The control device compares the latest heart rate with the past heart rate and the respiratory rate, and compares the result. When the difference value is equal to or greater than a predetermined value, the display device 8 is instructed to display the occurrence of abnormality.

[Blood pressure correction method]
When the control device 9 of the external unit 5 actually receives the measurement data transmitted from the first blood flow measurement sensor 2, the second blood flow measurement sensor 3, and the cardiopulmonary function sensor 4 by the wireless communication device 6, each measurement is performed. Data is automatically stored in the database 7.

  The database 7 includes the blood vessel inner wall displacement data (contraction of the inner diameter of the blood vessel) corresponding to the measurement result of the displacement of the blood vessel and the tissue around the blood vessel by the blood flow, and the heart rate and respiration rate by the cardiopulmonary function sensor 4. The pulse wave velocity and the degree of arteriosclerosis of the blood vessels (popliteal artery and thoracic aorta) obtained based on all the measurement data of each detection unit 12 of the first blood flow measurement sensor 2 and the second blood flow measurement sensor 3 are stored. Has been. The blood vessel characteristics include the proportion of blood vessel elasticity, the amount of plaque in the blood vessel (swelling of the intima), the proportion of arteriosclerosis, and the like.

  Here, blood pressure (arterial pressure) is expressed as cardiac output (heart rate × stroke volume) × vascular resistance (elasticity). Arterial pressure often undulates, especially during dehydration in blood vessels. There is a feature that becomes a waveform. When dehydration in the blood vessel (decrease in circulating blood volume) exists, the stroke volume greatly changes due to the change in intrathoracic pressure due to respiration, and the arterial pressure waveform fluctuates greatly.

  When intravascular dehydration occurs in the popliteal artery and thoracic aorta of the measurement subject, the control device 9 may have difficulty in accurately calculating the blood pressure values of these arteries.

  For this reason, the control device 9 uses the heart rate and respiration rate of the subject to measure respiratory characteristics (heart rate variation due to respiration) superimposed on the arterial pressure waveform of the popliteal artery and thoracic aorta of the subject. By removing as disturbance noise, the calculated values of blood pressure of each artery are corrected.

  Specifically, the control device 9 manages all measurement data acquired from the measurement subject over a long period of time, and monitors the time difference between the arterial pressure waveform of the popliteal artery and the arterial pressure waveform of the thoracic aorta. . When the time difference between the two arterial pressure waveforms is more than a predetermined value, the control device 9 corrects the time difference to be substantially constant using the heart rate and the respiratory rate.

  Therefore, the control device 9 can maintain the blood pressure value of the measurement site (popliteal artery and thoracic aorta) of the measurement subject in a state in which disturbance noise is removed, and calculate with high accuracy over a long period of time. Can do.

  Note that the control device 9 stores the blood pressure value of the measurement site (popliteal artery and thoracic aorta) of the measurement subject in the database 7, but changes in a shorter time as the management time (storage time) is longer. Since it is easy to grasp even a blood pressure fluctuation having a large width, the blood pressure can be corrected with high accuracy.

  Thus, since the first blood flow measurement sensor 2, the second blood flow measurement sensor 3, and the cardiopulmonary function sensor 4 are all installed in the vehicle seat S in a non-contact manner, the biological information detection apparatus 1 is measured. The measurement work can be easily performed without restraining the person, and the attachment / detachment work is unnecessary as in the method of contacting the person to be measured, and the blood pressure can be measured efficiently in a short time.

  As a result, even when the health condition of the measurement subject has deteriorated over a long period of time, it is possible to constantly monitor (ascertain the physical condition) while visually confirming the display device 8 of the external unit 5. The possibility of preventing snoozing and near-miss during driving is greatly increased.

  According to the biological information detecting apparatus 1 according to the present embodiment, the person to be measured can measure the blood pressure with high accuracy only by sitting on the vehicle seat S. Since there is no restriction on cuff pressure or posture, the burden on the vehicle driver can be reduced.

  In the above embodiment, the case where the biological information detecting device 1 is applied to the vehicle seat S has been described. However, the present invention is not limited thereto, and the first blood flow measurement sensor 3 is installed on the seating surface, and If the two blood flow measurement sensors 3 and the cardiopulmonary function sensor 4 can be installed, it can be widely applied to various seats with a backrest other than the vehicle seat. For example, it is also effective for long-term health management of business workers who need to sit for a long time (writers such as novels, creators of games and designs, salesclerks of product sales, managers of apartment houses, etc.).

  In the above embodiment, a water pack containing water or physiological saline in the back surface of the vehicle seat S so that the second blood flow measurement sensor 3 and the cardiopulmonary function sensor 4 are appropriately pressed against the back portion of the measurement subject. (Not shown) may be provided. Sensors 3 and 4 are arranged between the back of the person to be measured and the water pack, and due to the elasticity of the water pack, the sensors 3 and 4 are appropriately pressed against the back of the person to be measured, thereby improving blood pressure measurement accuracy. Can be made.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Biological information detection apparatus 2 1st blood flow measurement sensor 3 2nd blood flow measurement sensor 4 Cardiopulmonary function sensor 5 External unit 6, 14, 47 Wireless communication apparatus 7 Database 8 Display apparatus 9 Control apparatus 12 Detection unit 13 Measurement control part

Claims (5)

A first blood flow measuring means provided on a seating surface portion of the seat and measuring a blood flow state of the popliteal artery of the measurement subject seated on the seat;
A second blood flow measuring means provided on a back surface portion of the sheet for measuring a blood flow state of the subject's thoracic aorta;
From the blood flow data measured by the first blood flow measurement means and the blood flow data measured by the second blood flow measurement means, a pulse wave propagation speed and a degree of arteriosclerosis are obtained, and the pulse wave propagation speed and the arteriosclerosis are obtained. And a blood pressure calculating means for calculating the blood pressure of the popliteal artery and the thoracic aorta of the subject based on the degree of blood pressure. A database for storing each blood flow data obtained from the first blood flow measurement means and the second blood flow measurement means;
The blood pressure calculation means calculates the blood pressure of the popliteal artery and the thoracic aorta in time series based on the blood flow data accumulated in the database over a predetermined period, and the health condition of the subject to be measured The biological information detecting device according to claim 2, wherein the biological information detecting device is monitored. A cardiopulmonary function measuring unit that is provided on a back surface of the seat and measures a heart rate and a respiratory rate of the person to be measured; and the blood pressure calculating unit is configured to determine the person to be measured based on the heart rate and the respiratory rate. 3. The biological information according to claim 1, wherein the blood pressures of the popliteal artery and the thoracic aorta are respectively corrected so that the time difference between the pressure waveforms of the popliteal artery and the thoracic aorta is substantially constant. Detection device. The database stores heart rate and respiratory rate obtained from the cardiopulmonary function measuring means,
The blood pressure calculation means corrects the blood pressure of the popliteal artery and the thoracic aorta based on the heart rate and respiration rate accumulated in the database over a predetermined period, respectively. Biological information detection device.   A seat with a backrest comprising the biological information detecting device according to claim 1.

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