Biological signal detection device, and biological signal detection method

Abstract

To provide a biological signal detection device excellent in heat dissipation and maintainability, and a biological signal detection method.SOLUTION: An embodiment of a biological signal detection device of the present disclosure includes: an antenna unit that sweeps electromagnetic waves towards an occupant in a vehicle, and receives the reflected electromagnetic wave; and a module unit that detects vital signs of the occupant based on the reflected wave. The antenna unit and the module unit are provided to a seat belt buckle of a seat included in the vehicle.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a biological signal sensing device and a biological signal sensing method. [Background technology]

[0002] Recently, traffic accidents caused by drivers falling asleep at the wheel, loss of concentration due to drowsiness, poor physical condition, etc. have become a social problem. For this reason, development is underway of systems that estimate the driver's level of alertness and poor physical condition by detecting the driver's biological signals, and if it is determined that the driver is in a state that is impeding driving, will wake the driver, encourage them to take a break, make an emergency call, or make an emergency stop.

[0003] For example, Patent Document 1 discloses that a radar for detecting the pulse rate and the like of a seated person is provided inside the seat back so as not to give the seated person a foreign body sensation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 065526 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology disclosed in Patent Document 1, the radar for detecting biological signals is built into the seatback and is surrounded by a cover, which causes problems with heat dissipation.Furthermore, the technology disclosed in Patent Document 1 also has the problem of poor maintainability, as it is not easy to attach or detach the radar when repairing or replacing it.

[0006] The present disclosure has been made in consideration of the above circumstances, and contributes to providing a biological signal detection device and a biological signal detection method that are excellent in heat dissipation and maintainability. [Means for solving the problem]

[0007] One aspect of the biosignal detection device disclosed herein comprises an antenna unit that emits electromagnetic waves toward a vehicle occupant and receives reflected waves of the electromagnetic waves, and a module unit that detects the biosignal of the occupant based on the reflected waves, the antenna unit and the module unit being provided on a seat belt buckle of a seat provided in the vehicle.

[0008] In one aspect of the biosignal detection method of the present disclosure, an antenna unit provided on a seat belt buckle of a seat provided in a vehicle emits electromagnetic waves toward an occupant of the vehicle, the antenna unit receives reflected waves of the electromagnetic waves, and a module unit provided on the buckle detects the biosignal of the occupant based on the reflected waves. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a biological signal detection device and a biological signal detection method that are excellent in heat dissipation and maintainability. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the interior of a vehicle to which a biological signal detection device according to this embodiment is applied. [Figure 2] FIG. 2 is an enlarged view schematically illustrating an example of the buckle shown in FIG. [Figure 3] FIG. 3 is a perspective view that schematically shows an example of a buckle, with the biosignal detection device being seen through. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of the biological signal sensing device of this embodiment. [Figure 5] FIG. 5 is a diagram showing an example of the direction of electromagnetic wave sweep by the biological signal detection device of this embodiment. [Figure 6] FIG. 6 is a diagram showing an example of the posture of an occupant leaning against the backrest of a seat. [Figure 7] FIG. 7 is a diagram showing an example of the posture of an occupant sitting upright on the back of a seat. [Figure 8]FIG. 8 is a diagram showing an example of the direction of irradiating electromagnetic waves by the biological signal detection device of the first modification. [Figure 9] FIG. 9 is a diagram showing an example of the direction of irradiating electromagnetic waves by the biological signal detection device of the second modification. [Figure 10] FIG. 10 is a diagram showing an example of switching of the direction of emitting electromagnetic waves by the biological signal detection device of the third modification. [Figure 11] FIG. 11 is a diagram showing an example of switching of the direction of emitting electromagnetic waves by the biological signal detection device of the third modification. [Figure 12] FIG. 12 is a perspective view that schematically shows an example of a buckle of a biological signal detection device according to the fourth modification. [Figure 13] FIG. 13 is a plan view of the yz plane that schematically shows an example of a buckle according to the fourth modification. [Figure 14] FIG. 14 is a plan view of the yz plane that schematically shows an example of a buckle according to the fifth modification. [Figure 15] FIG. 15 is a circuit diagram showing an example of electrical connections in a biological signal sensing device according to the sixth modification. [Figure 16] FIG. 16 is a block diagram showing an example of the configuration of a biological signal detection device and a vehicle ECU according to the seventh modification. [Figure 17] FIG. 17 is a flowchart showing an example of processing performed by the biological signal detection device and the vehicle ECU of the seventh modification. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure (hereinafter simply referred to as "the present embodiment") will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiment. Furthermore, the following embodiment and modified examples can be combined as appropriate.

[0012] FIG. 1 is a diagram showing an example of the interior of a vehicle to which a biosignal detection device 100 of this embodiment is applied. The biosignal detection device 100 detects biosignals such as the heart rate and breathing of an occupant 1 of a vehicle such as an automobile. The occupant 1 may be either a driver or a passenger. As shown in FIG. 1, the biosignal detection device 100 of this embodiment is provided in a buckle 20 of a seat belt 10 provided in a vehicle. The occupant 1 is seated in a seat 30 wearing the seat belt 10. The seat belt 10 restrains the upper body and waist of the occupant 1 seated in the seat 30. The occupant 1 fastens the seat belt 10 by inserting a tongue plate 40 attached to the seat belt 10 into the buckle 20. The buckle 20 is located beside the seat 30.

[0013] FIG. 2 is an enlarged view schematically illustrating an example of the buckle 20 shown in FIG. 1 . FIG. 3 is a perspective view schematically illustrating an example of the buckle 20, with the biosignal detection device 100 seen through. The buckle 20 is formed with a receptacle 21. The receptacle 21 is an opening into which the tongue plate 40 is inserted and locks the inserted tongue plate 40. The buckle 20 is also provided with a PRESS button 23. The PRESS button 23 is a button for unlocking the tongue plate 40 inserted into the receptacle 21 and releasing the tongue plate 40 from the receptacle 21.

[0014] The buckle 20 also has a built-in biosignal detection device 100 of this embodiment. In this embodiment, the biosignal detection device 100 is described as being installed in a position closer to the seat 30 or the occupant 1 (positive direction of the y-axis) in the buckle 20. However, the location where the biosignal detection device 100 is installed is not limited to this, and the biosignal detection device 100 may be installed in a position farther away from the seat 30 or the occupant 1 (negative direction of the y-axis) in the buckle 20.

[0015] The biosignal detection device 100 of this embodiment radiates electromagnetic waves toward a vehicle occupant 1 and detects the biosignal of the occupant 1 based on the reflected waves of the electromagnetic waves. In this embodiment, the biosignal detection device 100 will be described as an example where the biosignal detection device 100 is a millimeter-wave radar module that radiates millimeter waves that can measure the breathing, heart rate, etc. of a living organism in a non-contact manner. However, the present invention is not limited to this, and the biosignal detection device 100 may also be a radar module (sensor module) that can detect biosignals by radiating electromagnetic waves of other frequency bands, such as microwaves.

[0016] Fig. 4 is a block diagram showing an example of the configuration of the biological signal detection device 100 of this embodiment. As shown in Fig. 4, the biological signal detection device 100 includes an antenna unit 110 and a module unit 120. The antenna unit 110 and the module unit 120 are included in the biological signal detection device 100, and are therefore provided in the buckle 20.

[0017] The antenna unit 110 emits electromagnetic waves toward the occupant 1 and receives reflected waves of the electromagnetic waves. In this embodiment, the antenna unit 110 emits the electromagnetic waves from the surface of the biological signal detection device 100 facing the seat 30 (the surface in the positive direction of the y-axis). For example, the antenna unit 110 emits the electromagnetic waves from the surface of the buckle 20 facing the seat 30 (the surface of the buckle 20 in the positive direction of the y-axis). The antenna unit 110 can be realized, for example, by a broadside array antenna.

[0018] The antenna unit 110 includes antenna elements 111-1 to 111-3 of the transmitting antenna and antenna elements 113-1 to 113-3 of the receiving antenna. In the following description, when there is no need to distinguish between the antenna elements 111-1 to 111-3 of the transmitting antenna, they may be simply referred to as antenna elements 111. Similarly, when there is no need to distinguish between the antenna elements 113-1 to 113-3 of the receiving antenna, they may be simply referred to as antenna elements 113. The example shown in FIG. 4 illustrates a case where there are three antenna elements 111 of the transmitting antenna and three antenna elements 113 of the receiving antenna. However, the number of each antenna element is not limited to this, and other combinations may be used.

[0019] Each antenna element 111 of the transmitting antenna radiates electromagnetic waves toward the occupant 1. Each antenna element 113 of the receiving antenna receives reflected waves that are the electromagnetic waves radiated toward the occupant 1 and reflected back by the occupant 1. As described above, the antenna unit 110 of this embodiment is realized by a broadside array antenna. Therefore, in this embodiment, each antenna element 111 of the transmitting antenna and each antenna element 113 of the receiving antenna are arranged in an array on a plane directly facing the seat 30 of the biological signal detection device 100 (a plane in the positive direction of the y-axis).

[0020] The module unit 120 controls the antenna unit 110 (each antenna element 111 of the transmitting antenna) to radiate electromagnetic waves toward the occupant 1. FIG. 5 is a diagram showing an example of the direction of radiating electromagnetic waves by the biological signal detection device 100 of this embodiment. In this embodiment, as shown in FIG. 5, the module unit 120 controls each antenna element 111 of the transmitting antenna so that the biological signal detection device 100 radiates electromagnetic waves toward the vicinity of the waist of the occupant 1. Specifically, the module unit 120 controls each antenna element 111 of the transmitting antenna so that the biological signal detection device 100 radiates electromagnetic waves toward the vicinity of the waist of the occupant 1 based on the position and posture of the buckle 20 that is assumed when the occupant 1 fastens the seat belt 10. The module unit 120 also detects the biological signal of the occupant 1 based on the reflected waves received by the antenna unit 110 (each antenna element 113 of the receiving antenna).

[0021] The module unit 120 is mainly configured with a well-known microcomputer including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), and also includes an oscillator, a signal processing circuit for performing transmission and reception processing, etc. However, part of the module unit 120 may be realized by a dedicated hardware circuit that does not have a CPU, etc.

[0022] Further, for example, part of the processing of module unit 120 may be executed by an external device such as a vehicle ECU (Electronic Control Unit). For example, module unit 120 may estimate the biological state of occupant 1 based on the detected biological signal of occupant 1, or the detected biological signal of occupant 1 may be output to the vehicle ECU, which may then perform this estimation processing. Examples of biological state estimation include, but are not limited to, estimation of the level of alertness or poor physical condition of occupant 1 (driver).

[0023] As described above, in this embodiment, the biological signal detection device 100 is provided in the buckle 20 of the seat belt 10, and unlike existing technology, the radar for detecting biological signals is not covered with a sheet or the like. Therefore, according to this embodiment, it is possible to provide a biological signal detection device 100 with excellent heat dissipation properties.

[0024] In particular, if a radar for detecting biosignals is installed inside a seat, as in existing technology, and the seat is equipped with a seat heater, the radar becomes more susceptible to the effects of heat, and the impact of heat dissipation becomes more severe. Therefore, according to this embodiment, a biosignal detection device 100 can be provided that is less susceptible to the effects of heat and has excellent heat dissipation properties, even when the seat 30 is equipped with a seat heater. Note that in EVs (Electric Vehicles), it is difficult to utilize the exhaust heat from the engine, and there is a tendency to rely on seat heaters rather than air conditioners for heating functions in order to improve power consumption, which increases the advantages of the biosignal detection device 100 of this embodiment.

[0025] Furthermore, in this embodiment, the biological signal detection device 100 is provided in the buckle 20 of the seat belt 10, and the radar for detecting biological signals is not covered with a sheet or the like, as in existing technology. Therefore, according to this embodiment, the biological signal detection device 100 can be easily attached and detached when repairing or replacing, and therefore, a biological signal detection device 100 with excellent maintainability can be provided. Furthermore, if the buckle 20 is replaced when repairing or replacing the biological signal detection device 100, maintainability can be further improved.

[0026] In addition, in this embodiment, the biological signal detection device 100 irradiates electromagnetic waves toward the waist area of ​​the occupant 1, whose position and posture are unlikely to change, thereby improving the detection accuracy of the biological signal. Furthermore, in this embodiment, it is possible to prevent the detection accuracy of the biological signal from deteriorating due to changes in the position and posture of the occupant 1, so that when the biological condition of the occupant 1 is estimated based on the biological signal, biological information can be stably estimated.

[0027] 6 and 7 are diagrams illustrating changes in posture of an occupant 1 seated in a seat 30. FIG. 6 is a diagram illustrating an example of the posture of the occupant 1 leaning against the backrest of the seat 30. FIG. 7 is a diagram illustrating an example of the posture of the occupant 1 sitting upright on the backrest of the seat 30. As is clear from the change in distance d in FIGS. 6 and 7, the position and posture of the upper body of the occupant 1 changes depending on whether the occupant 1 is leaning against the backrest of the seat 30 or sitting upright. Note that distance d indicates the distance between the back of the occupant 1 and the backrest of the seat 30. On the other hand, the waist area of ​​the occupant 1 is secured by the waist belt (not shown) of the seat belt 10, and therefore, as shown in area W in FIGS. 6 and 7, the position and posture of the occupant 1 are unlikely to change whether the occupant is leaning against the backrest of the seat 30 or sitting upright.

[0028] For example, the position of the occupant's waist when seated in the seat 30 is less dependent on the occupant's physical build, such as age (adult or child). Furthermore, the buckle 20 is structurally less likely to move left and right (in the vehicle width direction), and the position of the occupant's waist is also less likely to move left and right (in the vehicle width direction). Therefore, the distance between the occupant's waist and the biosignal detection device 100 is less likely to change. As described above, according to this embodiment, the detection accuracy of biosignals can be improved regardless of the occupant's physical build.

[0029] Furthermore, when radar for detecting vital signs is built into the seat back, as in existing technology, the distance between the radar and the occupant changes depending on the occupant's posture, which can reduce the accuracy of detecting vital signs and make it difficult to stably estimate vital signs.

[0030] (Variation 1) In the first modification, an example in which the biological signal detection device 100 sweeps electromagnetic waves toward the upper body of the occupant 1 will be described.

[0031] In the first modification, the antenna unit 110 emits electromagnetic waves from the top surface (the surface in the positive direction of the z-axis) of the biosignal detection device 100. For example, the antenna unit 110 emits electromagnetic waves from the surface into which the tongue plate 40 of the buckle 20 is inserted (the surface in the positive direction of the z-axis of the buckle 20). The antenna unit 110 can be realized, for example, by an end-fire array antenna.

[0032] In the first modification, the antenna elements 111 of the transmitting antenna and the antenna elements 113 of the receiving antenna are arranged in an array on the zx plane of the biological signal detection device 100, for example.

[0033] Fig. 8 is a diagram showing an example of the direction of emitting electromagnetic waves by the biological signal detection device 100 of Modification 1. In Modification 1, the module unit 120 controls each antenna element 111 of the transmitting antenna so that the biological signal detection device 100 radiates electromagnetic waves toward the upper body of the occupant 1, as shown in Fig. 8. Specifically, the module unit 120 controls each antenna element 111 of the transmitting antenna so that the biological signal detection device 100 radiates electromagnetic waves toward the upper body of the occupant 1, based on the position and posture of the buckle 20 that is assumed when the occupant 1 fastens the seat belt 10.

[0034] As described above, according to the first modification, since the electromagnetic waves are swept by the end-fire array antenna, the thickness of the biological signal detection device 100 can be reduced, and an increase in the thickness of the buckle 20 can also be suppressed.

[0035] (Variation 2) In the second modification, an example will be described in which the biological signal detection device 100 sweeps electromagnetic waves toward an occupant 201 positioned next to the occupant 1.

[0036] FIG. 9 is a diagram showing an example of the direction of electromagnetic wave emission by the biosignal detection device 100 of Modification 2. In Modification 2, as shown in FIG. 9, a seat 230 is located next to the seat 30 across the buckle 20, and an occupant 201 is seated in the seat. In Modification 2, the antenna unit 110 emits electromagnetic waves toward the occupant 201 and receives the reflected waves of the electromagnetic waves. Therefore, in Modification 2, the antenna unit 110 emits electromagnetic waves from the side of the biosignal detection device 100 opposite the seat 30 (the side facing the negative y-axis). For example, the antenna unit 110 emits electromagnetic waves from the side of the buckle 20 facing away from the seat 30 (the side of the buckle 20 facing the negative y-axis). The antenna unit 110 can be realized, for example, by a broadside array antenna. For example, the side of the buckle 20 facing away from the seat 30 is the side of the buckle 20 facing directly toward the seat 230.

[0037] The biological signal detection device 100 of the second modification may be configured to irradiate electromagnetic waves not only in the direction of the seat 230 but also in the direction of the seat 30 as described in the embodiment. In this case, the antenna units 110 may be provided on both sides of the biological signal detection device 100, and the electromagnetic waves may be irradiated while switching between the antenna units 110 to be irradiated.

[0038] According to the second modification, the biological signal detection device 100 can radiate electromagnetic waves in both directions, and can therefore detect the biological signals of another occupant, occupant 201. Therefore, according to the second modification, it is possible to detect the biological signals of all occupants in the vehicle without providing a biological signal detection device 100 on every buckle in the vehicle, and the number of installed biological signal detection devices 100 can be reduced.

[0039] (Variation 3) In the third modification, an example will be described in which the biological signal detection device 100 sweeps electromagnetic waves while switching the sweeping direction.

[0040] In Modification 3, the module unit 120 controls the antenna unit 110 (each antenna element 111 of the transmitting antenna) to radiate electromagnetic waves while switching the radiating direction toward the occupant 1. Fig. 10 and Fig. 11 are diagrams showing an example of switching the radiating direction of electromagnetic waves by the biological signal detection device 100 of Modification 3. As shown in Fig. 10 and Fig. 11, the antenna unit 110 radiates electromagnetic waves while switching the radiating direction.

[0041] Fig. 10 shows an example of switching the direction of emission of electromagnetic waves as viewed from the yz plane. In the example shown in Fig. 10, the antenna unit 110 (each antenna element 111 of the transmitting antenna) emits electromagnetic waves by switching the emission direction while looping in the order of state 311, state 313, state 315, state 311, .... In state 311, the antenna unit 110 emits electromagnetic waves toward the area below the seat back. In state 313, the antenna unit 110 emits electromagnetic waves toward the area in the center of the seat back. In state 315, the antenna unit 110 emits electromagnetic waves toward the area above the seat back.

[0042] Fig. 11 shows an example of switching the direction of emission of electromagnetic waves as viewed from the xy plane. In the example shown in Fig. 11, the antenna unit 110 (each antenna element 111 of the transmitting antenna) emits electromagnetic waves by switching the emission direction while looping in the order of state 321, state 323, state 325, state 321, .... In state 321, the antenna unit 110 emits electromagnetic waves toward the front of the thighs of the occupant 1 (around the knees). In state 323, the antenna unit 110 emits electromagnetic waves toward the center of the thighs of the occupant 1. In state 325, the antenna unit 110 emits electromagnetic waves toward the rear of the thighs of the occupant 1 (around the waist).

[0043] In the third modification, the module unit 120 controls each antenna element 111 of the transmitting antenna to radiate electromagnetic waves as shown in, for example, Figures 10 and 11. However, examples of switching the radiating direction of the electromagnetic waves are not limited to the examples in Figures 10 and 11, and for example, the radiating direction of the electromagnetic waves may be switched by combining the switching in Figures 10 and 11. The module unit 120 switches the radiating direction of the electromagnetic waves using, for example, a technique such as beamforming.

[0044] In the third modification, the module unit 120 controls the direction of the electromagnetic waves transmitted to the outside by electronic scanning. The module unit 120 continuously generates high-frequency (e.g., millimeter-wave frequency band) transmission signals that have been frequency-modulated so that the frequency repeatedly increases and decreases gradually over time, using, for example, a reference signal obtained from an oscillator. The module unit 120 sends the transmission signal generated for each antenna element 111 to the antenna element 111, causing each antenna element 111 to transmit the frequency-modulated electromagnetic waves. The module unit 120 changes the direction of the electromagnetic waves transmitted to the outside (e.g., a composite wave of the electromagnetic waves transmitted from each antenna element 111) by adjusting the phase of the electromagnetic waves transmitted from each antenna element 111.

[0045] In addition, in the third modification, the module unit 120 detects signals based on the reflected waves received for each scanning direction, and determines the signal whose phase fluctuation satisfies a predetermined condition as the biosignal. Specifically, the module unit 120 determines the signal with the highest reliability as the biosignal. For example, the module unit 120 determines that the signal with the largest fluctuation is a signal reflected from the human body, and determines it as the biosignal.

[0046] According to the third modification, by acquiring a plurality of signals while switching the scanning direction and selecting the most reliable signal from among them as the biological signal, the biological signal can be detected with high accuracy, and therefore the biological state can be estimated with high accuracy.

[0047] (Variation 4) In the fourth modification, an example will be described in which the antenna unit 110 has an antenna pattern formed of a conductive film.

[0048] FIG. 12 is a perspective view showing a schematic example of a buckle 20 of the biosignal detection device 100 of Modification 4. FIG. 13 is a plan view of the yz plane showing a schematic example of the buckle 20 of Modification 4. As shown in FIGS. 12 and 13, the antenna unit 110 (each antenna element 111 of the transmitting antenna and each antenna element 113 of the receiving antenna) is configured with an antenna pattern formed of a conductive film (metasurface). The conductive film may be a transparent electrode.

[0049] Therefore, according to the fourth modification, the thickness of the antenna portion 110 can be reduced, thereby reducing the thickness of the buckle 20. Furthermore, the biological signal detection device 100 can be provided in the buckle 20 without impairing the function of the seat belt 10.

[0050] (Variation 5) In the fifth modification, an example in which the antenna unit 110 is provided on the outside (surface) of the buckle 20 in the fourth modification will be described.

[0051] 14 is a plan view of the yz plane that schematically illustrates an example of the buckle 20 of Modification 5. As shown in FIG. 14, an antenna unit 110 configured with an antenna pattern formed of a conductive film (metasurface) is provided on the outer peripheral surface of the buckle 20.

[0052] Therefore, according to the fifth modification, the thickness of the antenna unit 110 can be reduced, thereby reducing the thickness of the buckle 20. Furthermore, the biological signal detection device 100 can be provided in the buckle 20 without impairing the functionality of the seat belt 10. For example, in the fifth modification, the antenna unit 110 is installed outside the housing of the buckle 20, so that changes to the shape of the existing buckle 20 can be avoided or kept to a minimum. Furthermore, in the fifth modification, the biological signal detection device 100 can be provided in the buckle 20 even when the housing of the buckle 20 is made of a material that is not transparent to radio waves.

[0053] (Variation 6) In the sixth modification, an example will be described in which the biological signal detection device 100 is activated when the occupant 1 is fastening the seat belt 10.

[0054] Fig. 15 is a circuit diagram showing an example of electrical connections of the biological signal detection device 100 of Modification 6. In the example shown in Fig. 15, an IG power supply (ignition power supply), the biological signal detection device 100, and a warning light 401 are electrically connected, and the power supply can be switched on and off by a seat belt switch 403.

[0055] In the sixth modification, when the IG power supply is on, the tongue plate 40 is not inserted into the buckle 20, and the switch 405 of the seat belt switch 403 is connected to the terminal 407, the warning light 401 is turned on. This makes it possible to notify the driver that the seat belt 10 has been forgotten to be fastened.

[0056] In addition, in variant example 6, when the IG power supply is turned on, the tongue plate 40 is inserted into the buckle 20, and the switch 405 of the seat belt switch 403 is connected to the terminal 409, power is supplied to the biological signal detection device 100, and the biological signal detection device 100 (antenna section 110 and module section 120) operates.

[0057] In this way, in the sixth modification, the biosignal detection device 100 (antenna unit 110 and module unit 120) is activated when the vehicle is in a state where it can travel and the occupant 1 is seated in the seat 30. More specifically, the biosignal detection device 100 (antenna unit 110 and module unit 120) is activated when the tongue plate 40 is inserted into the buckle 20.

[0058] Therefore, according to the sixth modification, when the occupant 1 is not fastening the seat belt 10, the biological signal detection device 100 is not activated, thereby reducing the load on the battery.

[0059] In the sixth modification, even when the IG power supply is off, power may be separately supplied to the biological signal detection device 100 to operate the biological signal detection device 100. In this way, even in cases such as when a child is left in a car, it is possible to detect that the child has been left behind.

[0060] In this case, for example, a timer (for example, 3 minutes) is set when the IG power supply is turned off, and during this time, the cycle of electromagnetic wave sweeping is lengthened to operate the biological signal detection device 100. Then, when the time set by the timer has elapsed, the power supply of the biological signal detection device 100 may be turned off. In this way, even in cases such as when a child is left in a car, the load on the battery can be reduced and it can be detected that the child has been left behind.

[0061] (Variation 7) In the seventh modification, an example of using the biological condition estimated by the biological signal detection device 100 will be described.

[0062] FIG. 16 is a block diagram showing an example of the configuration of the biosignal detection device 100 and the vehicle ECU 500 of Modification 7. The biosignal detection device 100 is the same as in the embodiment, and therefore a description thereof will be omitted. The vehicle ECU 500 includes a control unit 510. The control unit 510 receives a biostatus from the biosignal detection device 100 and performs control to prevent a vehicle accident based on the received biostatus. For example, the control unit 510 determines that the received biostatus indicates a decrease in the driver's alertness or poor physical condition, which may impair driving. In this case, the control unit 510 awakens the driver, encourages the driver to take a break, issues a warning, or makes an emergency call or makes an emergency stop. As described above, the biostatus may be estimated by the vehicle ECU 500 rather than the biosignal detection device 100.

[0063] FIG. 17 is a flowchart showing an example of processing performed by the biological signal detection device 100 and the vehicle ECU 500 according to the seventh modification.

[0064] First, the antenna unit 110 sweeps electromagnetic waves toward the occupant 1 (step S101) and receives the reflected waves of the electromagnetic waves (step S103).

[0065] Next, the module section 120 acquires a biological signal of the occupant 1 based on the reflected wave received by the antenna section 110 (step S105).

[0066] Next, the module section 120 estimates the biological condition of the occupant 1 based on the acquired biological signal of the occupant 1 (step S107).

[0067] Next, the control unit 510 receives the biological condition of the occupant 1 from the biological signal detection device 100 and determines whether the occupant 1 is feeling drowsy (step S109).

[0068] If occupant 1 is drowsy (Yes in step S109), control unit 510 wakes up the driver, urges the driver to take a rest, or issues a warning (step S111). On the other hand, if occupant 1 is not drowsy (No in step S109), control unit 510 does not issue a warning.

[0069] As described above, according to the above embodiment and each of the above modifications, it is possible to provide a biological signal detection device and a biological signal detection method that are excellent in heat dissipation and maintainability.

[0070] The above-described embodiment and each of the above-described modifications merely illustrate examples of specific embodiments of the present disclosure, and the technical scope of the present disclosure should not be construed as being limited by these. For example, the present disclosure can be implemented in various forms without departing from the gist or main features thereof. For example, the above-described embodiment and each of the above-described modifications may be appropriately combined in their respective constituent units. Furthermore, for example, some components may be deleted from all components in the above-described embodiment and each of the above-described modifications.

[0071] In the above description, the expression "... part" used for each component may be replaced with other expressions such as "... assembly," "... circuit," "... device," "... unit," or "... module." Also, the apparatus may be configured to be executed by a CPU using a program stored in memory.

[0072] The present disclosure includes the following aspects.

[0073] (1) an antenna unit that radiates electromagnetic waves toward a vehicle occupant and receives reflected waves of the electromagnetic waves; a module unit that detects a biological signal of the occupant based on the reflected wave, The biological signal detection device, wherein the antenna unit and the module unit are provided in a seat belt buckle of a seat provided in the vehicle.

[0074] (2) The biological signal detection device according to (1) above, wherein the antenna unit sweeps the electromagnetic waves in a direction directly facing the sheet.

[0075] (3) The biological signal detection device described in (1) above, wherein the antenna unit radiates the electromagnetic waves in a direction opposite to the direction in which the tongue plate of the seat belt is inserted into the buckle.

[0076] (4) The biological signal detection device according to (3) above, wherein the antenna unit has an endfire array antenna.

[0077] (5) The biological signal detection device according to (1) above, wherein the antenna unit sweeps the electromagnetic waves in a direction opposite to the sheet.

[0078] (6) The biological signal detection device described in (1) above, wherein the antenna unit is positioned in a position of the buckle closer to a seat provided in the vehicle than the tongue plate insertion port of the seat belt.

[0079] (7) The antenna unit radiates the electromagnetic waves by switching the radiating direction, The biological signal detection device according to any one of (1) to (6) above, wherein the module unit detects a signal for each scanning direction, and the signal whose phase fluctuation of the detected signal satisfies a condition is the biological signal.

[0080] (8) The biological signal detection device according to any one of (1) to (6) above, wherein the antenna section has an antenna pattern formed of a conductive film.

[0081] (9) The biological signal detection device according to (8), wherein the antenna unit is provided on the outside of the buckle.

[0082] (10) The biological signal detection device according to any one of (1) to (6) above, wherein the antenna unit and the module unit are activated after the occupant sits on the seat.

[0083] (11) The biological signal detection device according to any one of (1) to (6) above, wherein the antenna section and the module section are activated after the tongue plate is inserted into the buckle.

[0084] (12) The biological signal detection device according to any one of (1) to (6), wherein the module section estimates a biological condition of the occupant based on the biological signal.

[0085] (13) An antenna unit provided on a seat belt buckle of a seat provided in a vehicle radiates electromagnetic waves toward an occupant of the vehicle, the antenna unit receives a reflected wave of the electromagnetic wave, a module portion provided in the buckle that detects a biological signal of the occupant based on the reflected wave; Biosignal detection method.

[0086] (14) The biological signal detection method according to (13), wherein the electromagnetic waves are swept in a direction directly facing the sheet.

[0087] (15) The biological signal detection method according to (13), wherein the electromagnetic waves are swept in a direction opposite to the direction in which the tongue plate of the buckle is inserted.

[0088] (16) The biological signal detection method according to (13), wherein the electromagnetic waves are swept in a direction opposite to the sheet.

[0089] (17) The electromagnetic waves are irradiated while switching the irradiating direction, A biological signal detection method described in any one of (13) to (16) above, wherein the biological signal is a signal among the signals detected by the module unit for each scanning direction, the signal whose phase fluctuation satisfies a condition.

[0090] (18) The biological signal detection method according to any one of (13) to (16) above, wherein the antenna unit and the module unit are activated after the occupant sits on the seat.

[0091] (19) The biological signal detection method according to any one of (13) to (16) above, wherein the antenna section and the module section are activated after the tongue plate is inserted into the buckle.

[0092] (20) The biological signal detection method according to any one of (13) to (16) above, wherein the module section further estimates a biological condition of the occupant based on the biological signal. [Explanation of symbols]

[0093] 1 crew member 10 Seatbelts 20 Buckle 30 seats 40 Tongue Plate 100 Biological signal detection device 110 Antenna section 120 Module section 111, 111-1 to 111-3 antenna elements 113, 113-1 to 113-3 antenna elements 500 Vehicle ECU 510 control section

Claims

1. an antenna unit that radiates electromagnetic waves toward a vehicle occupant and receives reflected waves of the electromagnetic waves; a module unit that detects a biological signal of the occupant based on the reflected wave, The biological signal detection device, wherein the antenna unit and the module unit are provided in a seat belt buckle of a seat provided in the vehicle.

2. The biological signal detection device according to claim 1 , wherein the antenna unit sweeps the electromagnetic waves in a direction directly facing the sheet.

3. The biological signal detection device according to claim 1 , wherein the antenna unit radiates the electromagnetic waves in a direction opposite to a direction in which a tongue plate of the seat belt is inserted into the buckle.

4. The biological signal detection device according to claim 3 , wherein the antenna unit has an end-fire array antenna.

5. The biological signal detection device according to claim 1 , wherein the antenna unit sweeps the electromagnetic waves in a direction opposite to the sheet.

6. The biological signal detection device according to claim 1 , wherein the antenna unit is disposed in a position of the buckle closer to a seat provided in the vehicle than to an insertion opening of a tongue plate of the seat belt.

7. The antenna unit radiates the electromagnetic waves by switching the radiating direction, The biological signal detection device according to any one of claims 1 to 6, wherein the module unit detects a signal for each scanning direction, and the signal whose phase fluctuation of the detected signal satisfies a condition is taken as the biological signal.

8. 7. The biological signal detection device according to claim 1, wherein the antenna portion has an antenna pattern formed of a conductive film.

9. The biological signal detection device according to claim 8 , wherein the antenna unit is provided on the outside of the buckle.

10. 7. The biological signal detection device according to claim 1, wherein the antenna section and the module section are activated after the occupant sits on the seat.

11. 7. The biological signal detection device according to claim 1, wherein the antenna section and the module section are activated after the tongue plate is inserted into the buckle.

12. 7. The biological signal detection device according to claim 1, wherein the module portion estimates a biological condition of the occupant based on the biological signal.

13. An antenna unit provided on a seat belt buckle of a seat provided in a vehicle radiates electromagnetic waves toward an occupant of the vehicle, the antenna unit receives a reflected wave of the electromagnetic wave, a module portion provided in the buckle that detects a biological signal of the occupant based on the reflected wave; Biosignal detection method.

14. The biological signal detection method according to claim 13 , wherein the electromagnetic waves are swept in a direction directly facing the sheet.

15. The biological signal detection method according to claim 13 , wherein the electromagnetic wave is swept in a direction opposite to a direction in which a tongue plate of the buckle is inserted.

16. The biological signal sensing method according to claim 13 , wherein the electromagnetic waves are swept in a direction opposite to the sheet.

17. The electromagnetic waves are irradiated while switching the irradiating direction, A biological signal detection method according to any one of claims 13 to 16, wherein the biological signal is a signal among the signals detected by the module unit for each sweep direction, the signal whose phase fluctuation satisfies a condition.

18. The biological signal detection method according to any one of claims 13 to 16, wherein the antenna section and the module section are activated after the occupant sits on the seat.

19. The biological signal detection method according to any one of claims 13 to 16, wherein the antenna section and the module section are activated after the tongue plate is inserted into the buckle.

20. The biological signal detection method according to any one of claims 13 to 16, wherein the module unit further estimates a biological condition of the occupant based on the biological signal.

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