Biometric information detection device, vehicle and bed equipped therewith, and method for detecting biological information

Abstract

The present invention realizes a biological information detection apparatus that can obtain highly reliable biological signals from a human body while facilitating price reduction and downsizing of the apparatus by minimizing increase in scale of the apparatus. The biological information detection apparatus comprises: a reflection member (3) that reflects electromagnetic waves; and a radar device (2) that detects biological signals from a human body. The reflection member (3) is disposed between the human body and the radar device (2). The radar device (2) comprises: a transmission unit (2b) for emitting electromagnetic waves toward the human body and the reflection member (3); and a first reception unit (2c1) and a second reception unit (2c2) that receive reflected waves of the electromagnetic waves. The transmission unit (2b) emits electromagnetic waves including a first directional polarization component and a second directional polarization component different from the first directional polarization component. The reflection member (3) reflects the first directional polarization component included in the electromagnetic waves emitted from the transmission unit (2b) and allows transmission therethrough or absorption therein of the second directional polarization component included in the electromagnetic waves emitted from the transmission unit (2b). The first reception unit (2c1) receives at least the first directional polarization component in the reflected waves resulting from reflection by the reflection member (3) and by the human body. The second reception unit (2c2) receives the second directional polarization component in the reflected waves resulting from reflection by the human body.

Description

Technical Field

[0001] The present invention relates to a biological information detection device, a vehicle and a bed provided with the same, and a biological information detection method.

Background Art

[0002] Conventionally, as a biological information detection device for detecting a biological signal of a human body, for example, a non-contact biological sensor that detects human biological information by electromagnetic waves is disclosed in a configuration in which two sets are provided for a seat on which a person sits (for example, Patent Document 1). Each set of biological sensors is configured by arranging a first sensor and a second sensor that emit electromagnetic waves of different frequencies toward a person adjacent to each other. Among the first sensor and the second sensor, either one is used for detecting biological information including noise elements, and the other is used for detecting noise elements. The biological information of the human body is extracted by taking the difference from the noise elements. These sensors are configured by a Doppler radar or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional biological information detection device disclosed in Patent Document 1, since electromagnetic waves having different transmission and reception frequencies are irradiated and the first sensor and the second sensor for reception are used as radio wave sensors, the device may become large. In addition, in the above conventional biological information detection device, the device scale may be expanded and the introduction cost may be high.

[0005] This disclosure is made in view of the above, and aims to realize a biometric information detection device that can obtain highly reliable human biological signals while suppressing the expansion of the device size and achieving miniaturization and cost reduction of the device, a vehicle and a bed equipped therewith, and a biometric information detection method. [Means for solving the problem]

[0006] A biological information detection device according to one aspect of the present disclosure comprises a reflective member that reflects electromagnetic waves and a radar device that detects biological signals of a human body, wherein the reflective member is positioned between the human body and the radar device, and the radar device comprises a transmitting unit that irradiates electromagnetic waves toward the human body and the reflective member, respectively, and a first receiving unit and a second receiving unit that receive the reflected waves of the electromagnetic waves, wherein the transmitting unit irradiates electromagnetic waves including a first directional polarization component and a second directional polarization component different from the first directional polarization component, the reflective member reflects the first directional polarization component contained in the electromagnetic waves irradiated from the transmitting unit and transmits or absorbs the second directional polarization component contained in the electromagnetic waves irradiated from the transmitting unit, the first receiving unit receives at least the first directional polarization component of the reflected waves reflected by the human body and the reflective member, and the second receiving unit receives the second directional polarization component of the reflected waves reflected by the human body.

[0007] In this configuration, the transmitting unit emits electromagnetic waves (transmitted signal) that include a first directional polarization component and a second directional polarization component different from the first directional polarization component. The reflecting member reflects the first directional polarization component contained in the electromagnetic waves emitted from the transmitting unit and transmits or absorbs the second directional polarization component contained in the electromagnetic waves emitted from the transmitting unit. The first receiving unit receives at least the first directional polarization component of the reflected waves reflected by the human body and the reflecting member, and the second receiving unit receives the second directional polarization component of the reflected waves reflected by the human body. With this configuration, the second directional polarization component of the reflected waves reflected by the reflecting member is suppressed. As a result, the accuracy of the signal calculated from the second directional polarization component of the reflected waves received by the second receiving unit can be improved.

[0008] A biological information detection device according to one aspect of the present disclosure comprises a reflective member that reflects electromagnetic waves, a first radar device that irradiates the reflective member and the human body with electromagnetic waves polarized in a first direction and receives the reflected waves of said electromagnetic waves, and a second radar device that irradiates the reflective member and the human body with electromagnetic waves polarized in a second direction different from the first direction and receives the reflected waves of said electromagnetic waves, wherein the reflective member is positioned between the human body and the first radar device and reflects the electromagnetic waves polarized in a first direction irradiated from the first radar device and transmits or absorbs the electromagnetic waves polarized in a second direction irradiated from the second radar device.

[0009] In this configuration, the first radar device irradiates the reference surface of the reflective material and the subject's body surface with electromagnetic waves (transmitted signals) polarized in a first direction and receives the reflected waves. The second radar device irradiates the reflective material and the body with electromagnetic waves polarized in a second direction, different from the first direction, and receives the reflected waves. The reflective material reflects the electromagnetic waves polarized in a first direction irradiated from the first radar device and transmits or absorbs the electromagnetic waves polarized in a second direction irradiated from the second radar device. This configuration suppresses the reflected waves polarized in a second direction that are reflected by the reflective material. As a result, the accuracy of the signal calculated from the reflected waves polarized in a second direction transmitted and received by the second radar device can be improved.

[0010] One aspect of the present disclosure is a vehicle equipped with the biometric information detection device described above.

[0011] This configuration makes it possible to create a vehicle that can obtain highly reliable human biological signals while suppressing the expansion of the device size and achieving miniaturization and cost reduction.

[0012] One aspect of this disclosure, the bed, is equipped with the biometric information detection device described above.

[0013] This configuration allows for the miniaturization and cost reduction of the device by suppressing the expansion of the device size, while enabling the creation of a bed that can obtain highly reliable biological signals from the human body.

[0014] A biological information detection method according to one aspect of the present disclosure includes: a first electromagnetic wave irradiation step of irradiating a human body with electromagnetic waves including a first direction polarization component and a second direction polarization component different from the first direction polarization component; a first reflected wave reception step of receiving a reflected wave of the second direction polarization component from the first direction polarization component and the second direction polarization component included in the electromagnetic waves irradiated in the first electromagnetic wave irradiation step; a second electromagnetic wave irradiation step of irradiating a reflective member that reflects electromagnetic waves with electromagnetic waves including a first direction polarization component and a second direction polarization component; a second reflected wave reception step of receiving a reflected wave of the first direction polarization component from the first direction polarization component and the second direction polarization component included in the electromagnetic waves irradiated in the second electromagnetic wave irradiation step; a displacement signal generation step of generating a second displacement signal from the reflected wave received in the first reflected wave reception step and generating a first displacement signal from the reflected wave received in the second reflected wave reception step; and a biological signal generation step of separating the first displacement signal from the second displacement signal generated in the displacement signal generation step and generating a biological signal of the human body.

[0015] In this configuration, in the first electromagnetic wave irradiation step, an electromagnetic wave (transmission signal) containing a first direction polarization component and a second direction polarization component different from the first direction polarization component is irradiated toward the human body, and in the first reflected wave reception step, the reflected wave of the second direction polarization component from the first direction polarization component contained in the electromagnetic wave irradiated in the first electromagnetic wave irradiation step is received. In the second electromagnetic wave irradiation step, an electromagnetic wave containing a first direction polarization component and a second direction polarization component is irradiated toward the reflective member, and in the second reflected wave reception step, the reflected wave of the first direction polarization component from the first direction polarization component contained in the electromagnetic wave irradiated in the second electromagnetic wave irradiation step is received. Then, in the displacement signal generation step, a second displacement signal is generated from the reflected wave received in the first reflected wave reception step, and a first displacement signal is generated from the reflected wave received in the second reflected wave reception step, and in the biosignal generation step, the first displacement signal is separated from the second displacement signal generated in the displacement signal generation step to generate a biosignal of the human body. This configuration suppresses the second directional polarization component of the reflected wave reflected by the reflective member, thereby improving the accuracy of the second displacement signal generated based on the second directional polarization component of the reflected wave. In other words, it is possible to obtain a second displacement signal in which the influence of the reflected wave component from the reflective member is suppressed. Consequently, it is possible to obtain a highly reliable biosignal.

[0016] A biological information detection method according to one aspect of the present disclosure includes: an electromagnetic wave irradiation step of irradiating a reflective member that reflects electromagnetic waves with electromagnetic waves polarized in a first direction and irradiating a human body with electromagnetic waves polarized in a second direction different from the first direction; a reflected wave reception step of receiving the reflected waves of the electromagnetic waves polarized in the first direction irradiated in the electromagnetic wave irradiation step and receiving the reflected waves of the electromagnetic waves polarized in the second direction irradiated in the electromagnetic wave irradiation step; a displacement signal generation step of generating a second displacement signal from the reflected waves polarized in the second direction received in the reflected wave reception step and generating a first displacement signal from the reflected waves polarized in the first direction received in the reflected wave reception step; and a biological signal generation step of separating the first displacement signal from the second displacement signal generated in the displacement signal generation step and generating a biological signal of the human body.

[0017] In this configuration, in the electromagnetic wave irradiation step, electromagnetic waves with a first direction polarization are irradiated toward the reflecting member, and electromagnetic waves with a second direction polarization different from the first direction polarization are irradiated toward the human body. In the reflected wave reception step, the reflected waves of the electromagnetic waves with the first direction polarization irradiated in the electromagnetic wave irradiation step are received, as well as the reflected waves of the electromagnetic waves with the second direction polarization irradiated in the electromagnetic wave irradiation step. Then, in the displacement signal generation step, a second displacement signal is generated from the reflected waves with the second direction polarization received in the reflected wave reception step, and a first displacement signal is generated from the reflected waves with the first direction polarization received in the reflected wave reception step. In the biosignal generation step, the first displacement signal is separated from the second displacement signal generated in the displacement signal generation step, and a biosignal of the human body is generated. With this configuration, the second direction polarization component of the reflected waves reflected by the reflecting member is suppressed, and the accuracy of the second displacement signal generated based on the second direction polarization component of the reflected waves can be improved. In other words, a second displacement signal can be obtained in which the influence of the reflected wave component from the reflecting member is suppressed. Ultimately, this allows us to obtain highly reliable biosignals. [Effects of the Invention]

[0018] According to this disclosure, it is possible to realize a biometric information detection device that can obtain highly reliable human biological signals while suppressing the expansion of the device size and achieving miniaturization and cost reduction of the device, as well as a vehicle and bed equipped therewith, and a biometric information detection method. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a block diagram showing the schematic configuration of a biological information detection device according to Embodiment 1. [Figure 2] Figure 2 is a side view showing an example of application when the biometric information detection device according to Embodiment 1 is applied as a driver monitoring system. [Figure 3] Figure 3 is a schematic diagram showing an example of the shape of a reflective member. [Figure 4A] Figure 4A is a schematic diagram showing a first example of the antenna surface of a dielectric substrate that constitutes a radar device. [Figure 4B] FIG. 4B is a schematic diagram showing a second example of the antenna surface of the dielectric substrate constituting the radar device. [Figure 5] FIG. 5 is a diagram showing an example of a combination of the polarization of the electromagnetic wave reflected by the reference surface of the reflection member, the polarization of the electromagnetic wave transmitted from the transmission unit, the polarization of the electromagnetic wave received by the first reception unit, and the polarization of the electromagnetic wave received by the second reception unit in the biological information detection device according to Embodiment 1. [Figure 6A] FIG. 6A is a diagram showing an example of the second displacement signal. [Figure 6B] FIG. 6B is a diagram showing an example of the first displacement signal. [Figure 6C] FIG. 6C is a diagram showing an example of the biological signal. [Figure 7] FIG. 7 is a flowchart showing an example of the biological information detection process by the biological information detection device. [Figure 8] FIG. 8 is a block diagram showing a schematic configuration of the biological information detection device according to Embodiment 2. [Figure 9] FIG. 9 is a diagram showing an example of a combination of the polarization of the electromagnetic wave reflected by the reference surface of the reflection member, the polarization of the electromagnetic wave transmitted and received by the first radar device, and the polarization of the electromagnetic wave transmitted and received by the second radar device in the biological information detection device according to Embodiment 2. [Figure 10] FIG. 10 is a perspective view showing an example of the arrangement when the biological information detection device according to the present disclosure is applied to a vehicle. [Figure 11] FIG. 11 is a perspective view showing an example of the application when the biological information detection device according to the present disclosure is applied to a bed in a medical facility.

MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, the biological information detection device according to the embodiment, the vehicle and the bed provided with the same, and the biological information detection method will be described in detail based on the drawings. Note that the present disclosure is not limited by this embodiment.

[0021] (Embodiment 1) Figure 1 is a block diagram showing the schematic configuration of a biometric information detection device according to Embodiment 1. The biometric information detection device 1 according to Embodiment 1 is configured to include a radar device 2 and a reflective member 3.

[0022] Figure 2 is a side view showing an example of application when the biometric information detection device according to Embodiment 1 is applied as a driver monitoring system. The biometric information detection device 1 is applied, for example, to the driver monitoring system (DMS) shown in Figure 2 and is installed inside the seat 5 in the vehicle where the driver, who is the subject 4, is seated.

[0023] As shown in a magnified view of the dashed area in Figure 2, the radar device 2 is installed inside the internal material 5a of the sheet 5. With the biometric information detection device 1 installed in this manner, the biometric information detection device 1 detects changes in the distance from the radar device 2 to the body surface of the subject 4 where electromagnetic waves are irradiated, as body surface displacement. From this body surface displacement, the biometric information detection device 1 detects vital signs of the subject 4 driving the vehicle, such as heart rate, heart rate variability, respiratory rate, and respiratory depth.

[0024] The reflective member 3 is installed between the subject's body 4 and the radar device 2. Specifically, an example is that it is installed on the back side of the surface material 5b of the sheet 5 that is in contact with the subject's body 4, that is, on the side of the internal member 5a. The reflective member 3 is made of a material that reflects electromagnetic waves emitted from the radar device 2. The reflective member 3 is positioned, for example, directly or indirectly in contact with the subject's body 4. This positioning of the reflective member 3 should be such that it is placed on a member that picks up the subject's body movements. For example, as in this embodiment, the reflective member 3 is placed on the back or seat of the sheet 5.

[0025] Figure 3 is a schematic diagram showing an example of the shape of a reflective member. In the example shown in Figure 3, the reflective member 3 is provided with a plurality of reflectors 3a extending in the Y direction and arranged in the X direction. Each reflector 3a is made of a material that reflects radio waves, such as metal. In this disclosure, the wavelength of the electromagnetic waves transmitted and received by the radar device 2 is denoted as λ. The spacing a of each reflector 3a is, for example, 1λ. The width b of each reflector 3a in the X direction is, for example, 0.25λ. The length c of each reflector 3a in the Y direction is, for example, 10λ. The width d of the reflective member 3, which is composed of a plurality of reflectors 3a, in the X direction is, for example, 10λ. The spacing a of each reflector 3a, the width b of each reflector 3a in the X direction, the length c of each reflector 3a in the Y direction, and the width d of the reflective member 3 in the X direction are examples and are optimized according to the positional relationship and distance between the reflective member 3 and the radar device 2.

[0026] In the embodiment shown in Figure 3, the reflecting member 3 transmits radio waves with an electric field in the X direction and reflects radio waves with an electric field in the Y direction. Hereinafter, radio waves with an electric field in the X direction will also be referred to as "horizontally polarized waves," and radio waves with an electric field in the Y direction will also be referred to as "vertically polarized waves." In other words, in the embodiment shown in Figure 3, the reflecting member 3 transmits the horizontally polarized component and reflects the vertically polarized component.

[0027] The material of each reflector 3a is preferably conductive, such as metal foil or conductive fiber, that conforms to changes in the shape of the surface in contact with the human body, taking into consideration the comfort of the subject 4 sitting on the seat 5. However, it is not limited to this, and any material that reflects electromagnetic waves may be used, such as a hard metal plate. Furthermore, conductive fiber-reinforced plastic, a member plated with a conductive material, a member coated with conductive paint, or a member to which conductive tape is attached may also be used.

[0028] The radar device 2 is configured as a module having a signal generation unit 2a, a transmission unit 2b, a first receiving unit 2c1, a second receiving unit 2c2, an RF (radio frequency) signal processing unit 2d, and an arithmetic unit 2e. Each of these units is realized by software control processing of a microcomputer, by hardware configuration of electronic circuits, or by both software control processing of the microcomputer and hardware configuration of electronic circuits.

[0029] The RF signal generation unit 2a, the RF signal processing unit 2d, and the arithmetic unit 2e are configured as ICs (integrated circuits) and are arranged, for example, on the back surface of the antenna surface of a dielectric substrate. The electromagnetic wave modulation method used by the radar device 2 is the Doppler method, the FMCW (Frequency Modulated Continuous Wave radar) method, the pulse modulation method, etc. The electromagnetic wave modulation method used by the radar device 2 is not limited to the above methods, as long as it allows for the measurement of the distance to the target object.

[0030] The RF signal generation unit 2a generates a chirp signal as a transmission signal. The transmission unit 2b has multiple transmitting antennas Tx that irradiate the human body of the subject 4 and the reflective material 3 with electromagnetic waves. Figure 1 shows an example in which transmitting antennas Tx1, Tx2, and Tx3 are arranged in an array. The number of arrays (the number of transmitting antennas Tx that make up the transmission unit 2b) can be increased or decreased according to the required gain.

[0031] The transmitting unit 2b beamforms the transmission signal generated by the RF signal generation unit 2a towards the human body of the subject 4 and the reflective material 3, respectively, using multiple transmitting antennas Tx to irradiate them as electromagnetic waves. In this embodiment, the electromagnetic waves irradiated by the transmitting unit 2b are described as radio waves, but electromagnetic waves broadly include sound waves, light waves, and the like.

[0032] The first receiving unit 2c1 has multiple receiving antennas Rx that receive reflected waves that strike and reflect off the body surface of the subject 4, and reflected waves that strike and reflect off the reference surface of the reflecting member 3. Figure 1 shows an example in which the receiving antennas Rx1 and Rx2 are arranged in an array. The first receiving unit 2c1 can increase or decrease the number of arrays (the number of receiving antennas Rx that each constitute the first receiving unit 2c1) according to the required gain.

[0033] The second receiver unit 2c2 has multiple receiving antennas Rx that receive reflected waves that strike the surface of the subject's body 4 and reflect off it. Figure 1 shows an example in which the receiving antennas Rx3 and Rx4 are arranged in an array. The second receiver unit 2c2 can increase or decrease the number of arrays (the number of receiving antennas Rx that make up each of the second receiver units 2c2) according to the required gain.

[0034] The transmitting unit 2b, the first receiving unit 2c1, and the second receiving unit 2c2 are pattern antennas provided on the surface of the dielectric substrate constituting the radar device 2, specifically on the surface of the dielectric substrate facing the reference surface of the reflective member 3 and the human body surface of the subject 4. The surface of the dielectric substrate on which the transmitting unit 2b, the first receiving unit 2c1, and the second receiving unit 2c2 are provided will also be referred to as the "antenna surface" below.

[0035] Examples of materials for the dielectric substrate constituting the radar device 2 include low-temperature co-fired ceramic multilayer substrates (LTCC (Low Temperature Co-fired Ceramics) multilayer substrates), multilayer resin substrates formed by laminating multiple resin layers made of resins such as epoxy and polyimide, multilayer resin substrates formed by laminating multiple resin layers made of liquid crystal polymer (LCP) having a lower dielectric constant, multilayer resin substrates formed by laminating multiple resin layers made of fluororesin, and ceramic multilayer substrates (excluding low-temperature fired ceramic multilayer substrates).

[0036] Figure 4A is a schematic diagram showing a first example of the antenna surface of a dielectric substrate constituting a radar device. Figure 4B is a schematic diagram showing a second example of the antenna surface of a dielectric substrate constituting a radar device. As shown in Figures 4A and 4B, on the antenna surface of the dielectric substrate 20, the transmitting unit 2b, the first receiving unit 2c1, and the second receiving unit 2c2 are each surrounded by a GND pattern.

[0037] In the embodiment shown in Figure 4A, the transmitting unit 2b irradiates the reference surface of the reflecting member 3 or the human body surface of the subject 4 with circular polarization. The reflecting member 3 in the embodiment shown in Figure 3 reflects the vertical polarization component of the circularly polarized wave irradiated from the transmitting unit 2b and transmits the component including the horizontal polarization component other than the vertical polarization component of the circularly polarized wave. The first receiving unit 2c1 receives the vertical polarization component of the reflected wave reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the horizontal polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0038] In the embodiment shown in Figure 4B, the transmitter 2b irradiates the reference surface of the reflector 3 or the human body surface of the subject 4 with oblique polarization tilted with respect to the X and Y directions (for example, tilt θ = 45 [deg] with respect to the X and Y directions). The reflector 3 in the embodiment shown in Figure 3 reflects the vertical polarization component of the oblique polarization irradiated from the transmitter 2b and transmits the component including the horizontal polarization component other than the vertical polarization component of the oblique polarization. The first receiver 2c1 receives the vertical polarization component of the reflected wave reflected from the reference surface of the reflector 3 or the human body surface of the subject 4. The second receiver 2c2 receives the horizontal polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0039] In Figures 3, 4A, and 4B, the reflective member 3 reflects the vertical polarization component of the electromagnetic wave (transmitted signal) irradiated from the transmitting unit 2b, the first receiving unit 2c1 receives the vertical polarization component of the reflected wave reflected from the reference surface of the reflective member 3 or the human body surface of the subject 4, and the second receiving unit 2c2 receives the horizontal polarization component of the reflected wave reflected from the human body surface of the subject 4. However, the invention is not limited to this configuration. Figure 5 shows an example of a combination of the polarization of the electromagnetic wave reflected from the reference surface of the reflective member, the polarization of the electromagnetic wave transmitted from the transmitting unit, the polarization of the electromagnetic wave received by the first receiving unit, and the polarization of the electromagnetic wave received by the second receiving unit in the bio-information detection device according to Embodiment 1.

[0040] Specifically, Combination Example 1-1 shows an example of a combination of the reflective member 3 shown in Figure 3 and the transmitting unit 2b, first receiving unit 2c1, and second receiving unit 2c2 shown in Figure 4A. That is, in the embodiment of Combination Example 1-1, the transmitting unit 2b irradiates the reference surface of the reflective member 3 or the human body surface of the subject 4 with circular polarization. The reflective member 3 reflects the vertical polarization component of the circularly polarized electromagnetic wave irradiated from the transmitting unit 2b and transmits the component including the horizontal polarization component other than the vertical polarization component of the circularly polarized electromagnetic wave. The first receiving unit 2c1 receives the vertical polarization component of the reflected wave reflected from the reference surface of the reflective member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the horizontal polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0041] In the embodiment of combination example 1-2, the transmitting unit 2b irradiates the reference surface of the reflecting member 3 or the human body surface of the subject 4 with circular polarization. The reflecting member 3 reflects the vertical polarization component of the circularly polarized electromagnetic wave irradiated from the transmitting unit 2b and transmits the component including the horizontal polarization component other than the vertical polarization component of the circularly polarized electromagnetic wave. The first receiving unit 2c1 receives both polarization components (e.g., circular polarization) including both the vertical and horizontal polarization components of the reflected wave reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the horizontal polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0042] In the embodiment of combination example 1-3, the transmitting unit 2b irradiates the reference surface of the reflecting member 3 or the human body surface of the subject 4 with circular polarization. The reflecting member 3 reflects the horizontal polarization component of the circularly polarized electromagnetic wave irradiated from the transmitting unit 2b and transmits the component including the vertical polarization component other than the horizontal polarization component of the circularly polarized electromagnetic wave. The first receiving unit 2c1 receives the horizontal polarization component of the reflected wave reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the vertical polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0043] In the embodiment of combination example 1-4, the transmitting unit 2b irradiates the reference surface of the reflecting member 3 or the human body surface of the subject 4 with circular polarization. The reflecting member 3 reflects the horizontal polarization component of the circularly polarized electromagnetic wave irradiated from the transmitting unit 2b and transmits the component including the vertical polarization component other than the horizontal polarization component of the circularly polarized electromagnetic wave. The first receiving unit 2c1 receives both polarization components (e.g., circular polarization) including both the horizontal and vertical polarization components of the reflected wave reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the vertical polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0044] Combination Examples 1-5 show combination examples of the reflective member 3 shown in Figure 3 and the transmitting unit 2b, first receiving unit 2c1, and second receiving unit 2c2 shown in Figure 4B. That is, in the embodiment of Combination Example 1-5, the transmitting unit 2b irradiates electromagnetic waves with oblique polarization onto the reference surface of the reflective member 3 or the human body surface of the subject 4. The reflective member 3 reflects the vertical polarization component of the obliquely polarized electromagnetic waves irradiated from the transmitting unit 2b and transmits components including the horizontal polarization component other than the vertical polarization component of the obliquely polarized electromagnetic waves. The first receiving unit 2c1 receives the vertical polarization component of the reflected waves reflected from the reference surface of the reflective member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the horizontal polarization component of the reflected waves reflected from the human body surface of the subject 4.

[0045] In the embodiment of combination example 1-6, the transmitting unit 2b irradiates the reference surface of the reflecting member 3 or the human body surface of the subject 4 with oblique polarization. The reflecting member 3 reflects the vertical polarization component of the obliquely polarized electromagnetic wave irradiated from the transmitting unit 2b and transmits the component including the horizontal polarization component other than the vertical polarization component of the obliquely polarized electromagnetic wave. The first receiving unit 2c1 receives both polarization components (e.g., circular polarization) of the reflected wave reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4, including both the vertical and horizontal polarization components. The second receiving unit 2c2 receives the horizontal polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0046] In the embodiment of combination example 1-7, the transmitting unit 2b irradiates electromagnetic waves with oblique polarization onto the reference surface of the reflecting member 3 or the human body surface of the subject 4. The reflecting member 3 reflects the horizontal polarization component of the obliquely polarized electromagnetic waves irradiated from the transmitting unit 2b and transmits components including the vertical polarization component other than the horizontal polarization component of the obliquely polarized electromagnetic waves. The first receiving unit 2c1 receives the horizontal polarization component of the reflected waves reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4. The second receiving unit 2c2 receives the vertical polarization component of the reflected waves reflected from the human body surface of the subject 4.

[0047] In the embodiment of combination example 1-8, the transmitting unit 2b irradiates the reference surface of the reflecting member 3 or the human body surface of the subject 4 with oblique polarization. The reflecting member 3 reflects the horizontal polarization component of the obliquely polarized electromagnetic wave irradiated from the transmitting unit 2b and transmits the component of the obliquely polarized electromagnetic wave that includes the vertical polarization component other than the horizontal polarization component. The first receiving unit 2c1 receives both polarization components (e.g., circular polarization) of the reflected wave reflected from the reference surface of the reflecting member 3 or the human body surface of the subject 4, including both the horizontal and vertical polarization components. The second receiving unit 2c2 receives the vertical polarization component of the reflected wave reflected from the human body surface of the subject 4.

[0048] In the above combination examples, in the configurations of combination examples 1-2, 1-4, 1-6, and 1-8, the first receiving unit 2c1 receives both the horizontal and vertical polarization components of the reflected wave. However, when the first IF signal, which is the signal from the reference surface of the reflecting member 3, is acquired in the first IF signal acquisition step S102 of the bio-information detection processing (see Figure 7) described later, electromagnetic waves are irradiated from the transmitting antenna Tx of the transmitting unit 2b toward the reference surface of the reflecting member 3. Therefore, the polarization reflected from the reflecting member 3 is dominant over the polarization reflected from the surface of the subject 4's body as the polarization received by the first receiving unit 2c1. For this reason, even in the configurations of combination examples 1-2, 1-4, 1-6, and 1-8, where the first receiving unit 2c1 receives both the horizontal and vertical polarization components of the reflected wave, the influence of the reflection from the surface of the subject 4's body on the first IF signal acquired in the first IF signal acquisition step S102 is extremely small.

[0049] Furthermore, the reflective member 3 constituting the reference surface is not limited to the configuration shown in Figure 3. Specifically, the reflective member 3 constituting the reference surface may be, for example, a slot antenna, a dipole array, a patch antenna array, etc., and may be terminated with a predetermined impedance to absorb polarization components other than those received by the first receiving unit 2c1.

[0050] Thus, the transmitting unit 2b irradiates an electromagnetic wave (transmitted signal) that includes a first directional polarization and a second directional polarization different from the first directional polarization; the reflecting member 3 reflects the first directional polarization contained in the electromagnetic wave irradiated from the transmitting unit 2b and transmits or absorbs the second directional polarization contained in the electromagnetic wave irradiated from the transmitting unit 2b; the first receiving unit 2c1 receives at least the first directional polarization of the reflected wave reflected from the body surface of the subject 4 or the reference surface of the reflecting member 3; and the second receiving unit 2c2 receives the second directional polarization reflected from the body surface of the subject 4. In the following description, we will explain examples that adopt combination example 1-1 shown in Figure 5, that is, the shape of the reflecting member 3 shown in Figure 3 and the first example of the antenna surface of the dielectric substrate 20 constituting the radar device 2 shown in Figure 4A.

[0051] The RF signal processing unit 2d receives the reflected wave received by the first receiver unit 2c1, calculates the first IF signal, converts the calculated first IF signal into a digital signal using an AD converter, and outputs it to the arithmetic unit 2e.

[0052] Furthermore, the RF signal processing unit 2d receives the reflected wave received by the second receiver unit 2c2, calculates the second IF signal, converts the calculated second IF signal into a digital signal using an AD converter, and outputs it to the arithmetic unit 2e.

[0053] The computing unit 2e includes a displacement signal generation unit 2f, a biosignal generation unit 2g, and a bioinformation computing unit 2h.

[0054] The displacement signal generation unit 2f performs an FFT (Fast Fourier Transform) on the signal input from the RF signal processing unit 2d. Specifically, the displacement signal generation unit 2f generates a first displacement signal based on a first IF signal calculated from the reflected wave received by the first receiver unit 2c1. The displacement signal generation unit 2f also generates a second displacement signal based on a second IF signal calculated from the reflected wave received by the second receiver unit 2c2.

[0055] The biosignal generation unit 2g separates the first displacement signal, which was generated based on the first IF signal, from the second displacement signal, which was generated based on the second IF signal, and generates the biosignals of the human body of subject 4.

[0056] As a method for separating the first displacement signal from the second displacement signal to generate the biosignal of the human body of subject 4, for example, a method using an adaptive filter to which an algorithm such as LMS (Least Mean Square) is applied can be exemplified. However, the method for separating the first displacement signal from the second displacement signal is not limited to this, and may also be a method using blind source separation (BSS) such as independent component analysis (ICA), independent vector analysis (IVA), or independent low-rank matrix analysis (ILRMA). The present disclosure is not limited by the method for separating the first displacement signal from the second displacement signal.

[0057] Figure 6A shows an example of a second displacement signal. Figure 6B shows an example of a first displacement signal. Figure 6C shows an example of a biological signal. In Figures 6A, 6B, and 6C, the horizontal axis represents time [sec], and the vertical axis represents the displacement amount [μm] of each signal. The displacement amount of each signal is expressed with the average value in a certain time interval set to "0 [μm]".

[0058] The first displacement signal is generated based on the first IF signal calculated from the reflected wave reflected from the reference surface of the reflecting member 3 received by the first receiving unit 2c1. This first displacement signal consists of components such as road noise and vibrations caused by vehicle behavior, and is a noise component to the biological signal to be detected in the biological information detection device 1 according to this disclosure (see waveform B in Figure 6B).

[0059] In contrast, the second displacement signal is generated based on the second IF signal calculated from the reflected wave reflected from the body surface of the subject 4 received by the second receiving unit 2c2. This second displacement signal is a signal component in which the first displacement signal B shown in Figure 6B is superimposed on the biological signal to be detected in the biological information detection device 1 according to this disclosure (see waveform A in Figure 6A).

[0060] Therefore, by separating the first displacement signal B from the second displacement signal A, which is superimposed with the noise component first displacement signal B, the biological signal to be detected in the biological information detection device 1 according to this disclosure can be extracted (see waveform C in Figure 6C).

[0061] The bio-information processing unit 2h calculates vital signs such as heart rate, heart rate variability, respiratory rate, and respiratory depth of the subject 4 as bio-information from the bio-signal generation unit 2g.

[0062] Referring to Figure 7, the biological information detection process by the biological information detection device 1 according to Embodiment 1 will be described. Figure 7 is a flowchart showing an example of the biological information detection process by the biological information detection device.

[0063] First, the bio-information detection device 1 according to Embodiment 1 simultaneously performs a second IF signal acquisition step S101, which acquires a second IF signal, which is a signal from the surface of the subject 4's body, and a first IF signal acquisition step S102, which acquires a first IF signal, which is a signal from the reference surface of the reflective member 3. Specifically, the second IF signal acquisition step S101 and the first IF signal acquisition step S102 are switched and executed, for example, at each sampling timing of the computing device 2e. In addition, the RF signal generation unit 2a switches the radiation direction of electromagnetic waves from the transmitting antenna Tx of the transmitting unit 2b in synchronization with the sampling timing of the computing device 2e. More specifically, at the first sampling timing, electromagnetic waves are irradiated onto the surface of the subject 4's body, and at the second sampling timing following the first sampling timing, electromagnetic waves are irradiated onto the reference surface of the reflective member 3. In other words, the second IF signal acquisition step S101 and the first IF signal acquisition step S102 are executed in a time-division multiplexer.

[0064] The second IF signal acquisition step S101 includes a first electromagnetic wave irradiation step and a first reflected wave reception step. In the first electromagnetic wave irradiation step, the transmitting unit 2b irradiates the human body of the subject 4 with circularly polarized electromagnetic waves. In the first reflected wave reception step, the second receiving unit 2c2 receives the horizontally polarized component of the reflected wave that hits the surface of the human body of the subject 4 and is reflected from the circularly polarized component of the electromagnetic wave irradiated in the first electromagnetic wave irradiation step as a human body surface signal.

[0065] Furthermore, the first IF signal acquisition step S102 includes a second electromagnetic wave irradiation step and a second reflected wave reception step. In the second electromagnetic wave irradiation step, the transmitting unit 2b irradiates the reflecting member 3 with circularly polarized electromagnetic waves. In the second reflected wave reception step, the first receiving unit 2c1 receives the vertically polarized component of the reflected wave that is reflected after hitting the reference surface of the reflecting member 3, from the circularly polarized component of the electromagnetic wave irradiated in the second electromagnetic wave irradiation step, as a reference surface signal.

[0066] Next, the bio-information detection device 1 executes the displacement signal generation step S103. In the displacement signal generation step S103, the displacement signal generation unit 2f generates a second displacement signal indicating the body surface displacement of the subject 4 from the second IF signal acquired in the second IF signal acquisition step S101. The displacement signal generation unit 2f also generates a first displacement signal indicating the reference surface displacement of the reflective member 3 from the first IF signal acquired in the first IF signal acquisition step S102.

[0067] Next, the bio-information detection device 1 performs a biosignal generation step S104 (vibration removal process). In the biosignal generation step S104, the biosignal generation unit 2g separates the first displacement signal, which was similarly generated in the displacement signal generation step S103, from the second displacement signal, which was similarly generated in the displacement signal generation step S103. This biosignal generation step S104 suppresses components such as road noise and vibrations caused by vehicle behavior, and generates biosignals of the human body of the subject 4 to be detected by the bio-information detection device 1 according to this disclosure. Specifically, for example, the biosignal C shown in Figure 6C includes vital signs such as the subject 4's respiration and heart rate.

[0068] Next, the biological information detection device 1 performs the vital sign acquisition step S105. In the vital sign acquisition step S105, the biological information calculation unit 2h acquires the vital signs of the subject 4 from the biological signals generated by the biological signal generation unit 2g in the biological signal generation step S104. A detailed explanation of the vital sign acquisition method is omitted here, but this disclosure is not limited by the vital sign acquisition method.

[0069] According to the bio-information detection device 1 and bio-information detection method of this embodiment 1, an RF signal generation unit 2a, a transmission unit 2b, a first receiving unit 2c1, a second receiving unit 2c2, an RF (radio frequency) signal processing unit 2d, and a displacement signal generation unit 2f, all configured within a single radar device 2, irradiate and receive (ingress and egress) electromagnetic waves onto the human body of the subject 4 and the reflective member 3, thereby acquiring a second displacement signal indicating the displacement of the body surface of the subject 4 and a first displacement signal indicating the displacement of the reference surface of the reflective member 3. Then, the first displacement signal is separated from the acquired second displacement signal by the bio-signal generation unit 2g, and a bio-signal of the human body is generated with noise components superimposed on the second displacement signal suppressed.

[0070] Therefore, unlike conventional bio-information detection devices that use a first sensor and a second sensor that irradiate and receive electromagnetic waves of different frequencies as radio wave sensors, a single radar device 2 is used as a radio wave sensor to obtain a bio-signal of the human body with suppressed noise components. For this reason, the bio-information detection device 1 according to Embodiment 1 can be made smaller and less expensive by suppressing the expansion of the size of the bio-information detection device 1.

[0071] Here, assuming that the reflective member 3 reflects all polarization components of the electromagnetic wave irradiated from the transmitting unit 2b, and the first receiving unit 2c1 and the second receiving unit 2c2 receive all polarization components of the reflected wave, the second displacement signal generated based on the second IF signal calculated from all polarization components of the reflected wave received by the second receiving unit 2c2 may have reduced accuracy due to the influence of the reflected wave reflected by the reference surface of the reflective member 3.

[0072] In contrast, in this embodiment, as described above, the transmitting unit 2b irradiates an electromagnetic wave (transmitted signal) containing a first directional polarization component and a second directional polarization component different from the first directional polarization component, and the reflecting member 3 reflects the first directional polarization component contained in the electromagnetic wave irradiated from the transmitting unit 2b and transmits or absorbs the second directional polarization component contained in the electromagnetic wave irradiated from the transmitting unit 2b. The first receiving unit 2c1 receives at least the first directional polarization component of the reflected wave reflected from the body surface of the subject 4 and the reference surface of the reflecting member 3, and the second receiving unit 2c2 receives the second directional polarization component of the reflected wave reflected from the body surface of the subject 4. With this configuration, the second directional polarization component of the reflected wave reflected by the reflecting member 3 is suppressed, and the accuracy of the second displacement signal generated based on the second IF signal calculated from the second directional polarization reflected wave received by the second receiving unit 2c2 can be improved. In other words, a second displacement signal with the influence of the reflected wave component from the reflecting member 3 suppressed can be obtained. Ultimately, this allows us to obtain highly reliable biosignals from four human subjects.

[0073] (Embodiment 2) Figure 8 is a block diagram showing the schematic configuration of a biometric information detection device according to Embodiment 2. The biometric information detection device 1a according to Embodiment 2 comprises a first radar device 21, a second radar device 22, a computing device 23, and a reflective member 3. Similar to the biometric information detection device 1 according to Embodiment 1, the biometric information detection device 1a is applied to a DMS, for example, and is installed inside the seat 5 in a vehicle where the driver, who is the subject 4, is seated.

[0074] The first radar device 21 is, for example, a radar device for a reflective member. The first radar device 21 irradiates the reflective member 3 with electromagnetic waves in vertical polarization and receives the vertically polarized reflected waves that hit the reference surface of the reflective member 3 and are reflected. The first radar device 21 has an RF signal processing unit 21a inside. The RF signal processing unit 21a receives the reflected waves received by the first radar device 21 as input, calculates a first IF signal, converts it into a digital signal using an AD converter, and outputs it to the arithmetic unit 23.

[0075] The second radar device 22 is, for example, a human body radar device. The second radar device 22 synchronously with the first radar device 21 and irradiates the human body of the subject 4 with electromagnetic waves in the same frequency band as the first radar device 21 in horizontal polarization, and receives the horizontally polarized reflected waves that hit the surface of the subject 4's body and reflect off it. The second radar device 22 has an RF signal processing unit 22a inside it. The RF signal processing unit 22a receives the reflected waves received by the second radar device 22 as input, calculates a second IF signal, converts it into a digital signal using an AD converter, and outputs it to the arithmetic unit 23.

[0076] In the configuration described above, the reflective member 3 is the same as in the embodiment described with reference to Figure 3 of Embodiment 1. Specifically, the reflective member 3 reflects the vertical polarization component and transmits the horizontal polarization component.

[0077] Note that the first radar device 21, the second radar device 22, and the reflective member 3 are not limited to the embodiments described above. Figure 9 is a diagram showing an example of a combination of the polarization of electromagnetic waves reflected from the reference surface of the reflective member, the polarization of electromagnetic waves transmitted and received by the first radar device, and the polarization of electromagnetic waves transmitted and received by the second radar device in the bio-information detection device according to Embodiment 2.

[0078] Specifically, Combination Example 2-1 shows an example of a combination in the configuration described above. That is, in the embodiment of Combination Example 2-1, the first radar device 21 irradiates electromagnetic waves with vertical polarization toward the reflecting member 3 and receives the reflected waves of vertical polarization that strike the reference surface of the reflecting member 3 and are reflected. The second radar device 22 irradiates electromagnetic waves with horizontal polarization toward the human body of the subject 4 and receives the reflected waves of horizontal polarization that strike the surface of the human body of the subject 4 and are reflected.

[0079] In the embodiment of combination example 2-2, the first radar device 21 irradiates electromagnetic waves with horizontal polarization toward the reflecting member 3 and receives the horizontally polarized reflected waves that strike the reference surface of the reflecting member 3 and are reflected. The second radar device 22 irradiates electromagnetic waves with vertical polarization toward the human body of the subject 4 and receives the vertically polarized reflected waves that strike the surface of the human body of the subject 4 and are reflected.

[0080] Furthermore, the reflective member 3 constituting the reference surface may, similar to Embodiment 1, be in the form of, for example, a slot antenna, a dipole array, a patch antenna array, etc., and may be terminated with a predetermined impedance to absorb polarizations other than those received by the first receiving unit 2c1.

[0081] Thus, the first radar device 21 irradiates the reference surface of the reflective member 3 and the human body surface of the subject 4 with electromagnetic waves (transmitted signals) polarized in a first direction and receives the reflected waves of said electromagnetic waves, the second radar device 22 irradiates the reference surface of the reflective member 3 and the human body surface of the subject 4 with electromagnetic waves polarized in a second direction different from the first direction and receives the reflected waves of said electromagnetic waves, and the reflective member 3 is configured to reflect the electromagnetic waves polarized in a first direction irradiated from the first radar device 21 and to transmit or absorb the electromagnetic waves polarized in a second direction irradiated from the second radar device 22. The following description will explain examples adopting each configuration of combination example 2-1 shown in Figure 9.

[0082] The arithmetic unit 23 has substantially the same components as the arithmetic unit 2e of the biological information detection device 1 according to Embodiment 1. Specifically, the arithmetic unit 23 includes a displacement signal generation unit 23a, a biological signal generation unit 23b, and a biological information calculation unit 23c.

[0083] The displacement signal generation unit 23a generates a first displacement signal based on the first IF signal output from the RF signal processing unit 21a of the first radar device 21. The displacement signal generation unit 23a also generates a second displacement signal based on the second IF signal output from the RF signal processing unit 22a of the second radar device 22.

[0084] The biosignal generation unit 23b separates the first displacement signal, which is generated based on the first IF signal, from the second displacement signal, which is generated based on the second IF signal, and generates the biosignals of the human body of subject 4. However, this disclosure is not limited to the method of separating the first displacement signal from the second displacement signal, as in Embodiment 1.

[0085] The first displacement signal is generated based on the first IF signal calculated from the reflected wave reflected from the reference surface of the reflecting member 3 received by the first receiving unit 2c1. This first displacement signal consists of components such as road noise and vibrations caused by vehicle behavior, and is a noise component to the biological signal to be detected in the biological information detection device 1 according to this disclosure (see waveform B in Figure 6B).

[0086] In contrast, the second displacement signal is generated based on the second IF signal calculated from the reflected wave reflected from the body surface of the subject 4 received by the second receiving unit 2c2. This second displacement signal is a signal component in which the first displacement signal B shown in Figure 6B is superimposed on the biological signal to be detected in the biological information detection device 1 according to this disclosure (see waveform A in Figure 6A).

[0087] Therefore, similar to Embodiment 1, by separating the first displacement signal B from the second displacement signal A which is superimposed with the noise component, the biological signal to be detected in the biological information detection device 1 according to this disclosure can be extracted (see waveform C in Figure 6C).

[0088] The bio-information processing unit 23c calculates vital signs such as heart rate, heart rate variability, respiratory rate, and respiratory depth of the subject 4 as bio-information from the bio-signal generation unit 23b.

[0089] The sequence of steps for biometric information detection processing by the biometric information detection device 1a according to Embodiment 2 is the same as in Embodiment 1. Here, with reference to Figure 7, the biometric information detection processing by the biometric information detection device 1a according to Embodiment 2 will be described.

[0090] First, the bio-information detection device 1a according to Embodiment 2 simultaneously performs a second IF signal acquisition step S101, which acquires a second IF signal, which is a signal from the human body surface of the subject 4, and a first IF signal acquisition step S102, which acquires a first IF signal, which is a signal from the reference surface of the reflective member 3. Specifically, the second IF signal acquisition step S101 and the first IF signal acquisition step S102 are switched and executed, for example, at each sampling timing of the arithmetic unit 23. In other words, the second IF signal acquisition step S101 and the first IF signal acquisition step S102 are executed in a time-division multiplexer.

[0091] The second IF signal acquisition step S101 includes an electromagnetic wave irradiation step and a reflected wave reception step. In the electromagnetic wave irradiation step, the second radar device 22 irradiates the subject 4 with horizontally polarized electromagnetic waves. In the reflected wave reception step, the second radar device 22 receives the horizontally polarized reflected waves that have struck the surface of the subject 4's body and been reflected as a body surface signal.

[0092] Furthermore, the first IF signal acquisition step S102, like the second IF signal acquisition step S101, includes an electromagnetic wave irradiation step and a reflected wave reception step. In the electromagnetic wave irradiation step, the first radar device 21 irradiates the reflector member 3 with vertically polarized electromagnetic waves. In the reflected wave reception step, the first radar device 21 receives the vertically polarized reflected waves that have struck the reference surface of the reflector member 3 and been reflected as a reference surface signal.

[0093] Next, the bio-information detection device 1a executes the displacement signal generation step S103. In the displacement signal generation step S103, the displacement signal generation unit 23a generates a second displacement signal indicating the body surface displacement of the subject 4 from the second IF signal acquired in the second IF signal acquisition step S101. The displacement signal generation unit 23a also generates a first displacement signal indicating the reference surface displacement of the reflective member 3 from the first IF signal acquired in the first IF signal acquisition step S102.

[0094] Next, the bio-information detection device 1a executes the biosignal generation step S104. In the biosignal generation step S104, the biosignal generation unit 23b separates the first displacement signal, which was similarly generated in the displacement signal generation step S103, from the second displacement signal, which was similarly generated in the displacement signal generation step S103. This biosignal generation step S104 suppresses components such as road noise and vibrations caused by vehicle behavior, and generates the biosignals of the human body of the subject 4 to be detected by the bio-information detection device 1 according to this disclosure. Specifically, for example, the biosignal C shown in Figure 6C includes the vital signs of the subject 4, namely respiration and heart rate.

[0095] Next, the biological information detection device 1a performs the vital sign acquisition step S105. In the vital sign acquisition step S105, the biological information calculation unit 23c acquires the vital signs of the subject 4 from the biological signals generated by the biological signal generation unit 23b in the biological signal generation step S104. A detailed explanation of the vital sign acquisition method is omitted here, as it is similar to Embodiment 1, but this disclosure is not limited to the vital sign acquisition method.

[0096] According to the bio-information detection device 1a and bio-information detection method of this embodiment 2, electromagnetic waves are irradiated and received (incidentally and ingress-ingress) onto the human body of the subject 4 and the reflective member 3 by the first radar device 21 and the second radar device 22, which irradiate and receive electromagnetic waves of the same frequency band, and a second displacement signal indicating the displacement of the body surface of the human body of the subject 4 and a first displacement signal indicating the displacement of the reference surface of the reflective member 3 are acquired. Then, the first displacement signal is separated from the acquired second displacement signal by the bio-signal generation unit 2g, and a bio-signal of the human body is generated in which noise components superimposed on the second displacement signal are suppressed.

[0097] Therefore, unlike conventional bio-information detection devices that use a first sensor and a second sensor that irradiate and receive electromagnetic waves of different frequencies as radio wave sensors, the first radar device 21 and the second radar device 22, which transmit and receive electromagnetic waves in the same frequency band respectively, are used as radio wave sensors, thereby obtaining a bio-signal of the human body with suppressed noise components. For this reason, the bio-information detection device 1a according to Embodiment 2 can be made smaller and less expensive by suppressing the expansion of the size of the bio-information detection device 1a.

[0098] Here, assuming that the first radar device 21 irradiates the reference surface of the reflecting member 3 with fully polarized electromagnetic waves (transmitted signal), the second radar device 22 irradiates the human body surface of the subject 4 with fully polarized electromagnetic waves (transmitted signal), the reflecting member 3 reflects the fully polarized electromagnetic waves irradiated from the first radar device 21, and the first radar device 21 and the second radar device 22 receive the fully polarized reflected waves, the second displacement signal generated based on the second IF signal calculated from the fully polarized reflected waves received by the second radar device 22 may have reduced accuracy due to the influence of the reflected waves reflected from the reference surface of the reflecting member 3.

[0099] In contrast, in this embodiment, as described above, the first radar device 21 irradiates the reference surface of the reflective member 3 and the human body surface of the subject 4 with electromagnetic waves (transmitted signal) with a first direction polarization and receives the reflected waves of said electromagnetic waves. The second radar device 22 irradiates the reference surface of the reflective member 3 and the human body surface of the subject 4 with electromagnetic waves with a second direction polarization different from the first direction polarization and receives the reflected waves of said electromagnetic waves. The reflective member 3 reflects the electromagnetic waves with a first direction polarization irradiated from the first radar device 21 and transmits or absorbs the electromagnetic waves with a second direction polarization irradiated from the second radar device 22. With this configuration, the reflected waves of the second direction polarization reflected by the reflective member 3 are suppressed, and the accuracy of the second displacement signal generated based on the second IF signal calculated from the reflected waves of the second direction polarization transmitted and received by the second radar device 22 can be improved. In other words, a second displacement signal can be obtained in which the influence of the reflected wave component from the reflective member 3 is suppressed. Consequently, similar to Embodiment 1, highly reliable biosignals from the human body of subject 4 can be obtained.

[0100] Furthermore, in this embodiment, the first radar device 21 and the second radar device 22 can each be placed at any position, allowing electromagnetic waves to be irradiated onto the subject's body 4 and the reflective member 3 from various angles. Also, since reflected waves from the subject's body surface and the reference surface of the reflective member 3 can be received from various angles, the degree of freedom in the placement of the reflective member 3 is increased. For this reason, the arrangement configuration of the bio-information detection device 1a can be designed flexibly.

[0101] Figure 10 is a perspective view showing an example of the arrangement when the biometric information detection device according to this disclosure is applied to a vehicle. In Embodiment 1 described above, the case in which the radar device 2 and the reflective member 3 are arranged inside the seat 41 of the vehicle 40 was explained, but it is sufficient if the reflective member 3 is placed between the human body of the subject 4 and the radar device 2 on a member that picks up the body movements of the human body, and the radar device 2 is positioned at a location where electromagnetic waves can be irradiated to both the human body and the reflective member 3, and reflected waves from both the human body and the reflective member 3 can be received. Alternatively, for example, the radar device 2 may be placed on the dashboard 42, the rearview mirror 43, or the ceiling 44 inside the vehicle, and the reflective member 3 may be placed on the seat belt 45.

[0102] Furthermore, while the above-described embodiment 2 describes a case where the first radar device 21, the second radar device 22, and the reflective member 3 are arranged inside the seat 41 of the vehicle 40, it is sufficient if the reflective member 3 is positioned between the subject 4's body and the second radar device 22 on a component that picks up the body's movements, the first radar device 21 is positioned at a location that can irradiate the body with electromagnetic waves and receive reflected waves from the body, and the second radar device 22 is positioned at a location that can irradiate the reflective member 3 with electromagnetic waves and receive reflected waves from the reflective member 3. For example, the first radar device 21 may be positioned on the dashboard 42, the second radar device 22 on the rearview mirror 43, and the reflective member 3 on the seat belt 45. Moreover, the reflective member 3 can be replaced with a seat heater made of a metal component such as nichrome wire. In this case, for example, the first radar device 21, the second radar device 22, and the reflective member 3 may be arranged under the seat surface of the seat 41.

[0103] With these configurations, it is possible to provide a vehicle 40 equipped with a biometric information detection device 1,1a that can obtain highly reliable human biological signals while suppressing an increase in the size of the biometric information detection device 1,1a and achieving miniaturization and cost reduction of the biometric information detection device 1,1a.

[0104] Furthermore, the biometric information detection devices 1 and 1a in each embodiment can be applied not only to vehicles, but also, for example, to the driver's seat of an airplane or train as a driver monitoring system. Moreover, the biometric information detection devices 1 and 1a may be applied to beds in medical facilities such as hospitals. Figure 11 is a perspective view showing an example of application when the biometric information detection device according to this disclosure is applied to a bed in a medical facility.

[0105] When the biometric information detection device 1 according to Embodiment 1 described above is applied to a bed in a medical facility, the radar device 2 and reflective member 3 may be configured to be placed inside the mattress of the bed 51 in the medical facility. In this case as well, the reflective member 3 is placed between the subject's body and the radar device 2 on a member that picks up the body's movements, and the radar device 2 is configured to be placed in a location where electromagnetic waves can be irradiated to both the body and the reflective member 3, and where reflected waves from both the body and the reflective member 3 can be received. Alternatively, for example, the radar device 2 may be placed on the wall 52, ceiling 53, chair 54, lighting 55, etc. in a hospital room, and the reflective member 3 may be placed on a blanket (not shown) covering the subject.

[0106] Furthermore, when the biometric information detection device 1a according to Embodiment 2 described above is applied to a bed in a medical facility, the first radar device 21, the second radar device 22, and the reflective member 3 may be configured to be placed inside the mattress of the bed 51. In this case as well, it is sufficient that the reflective member 3 is placed on a member that picks up the body movements of the subject between the subject's body and the second radar device 22, the first radar device 21 is placed in a location that can irradiate the subject with electromagnetic waves and receive reflected waves from the subject, and the second radar device 22 is placed in a location that can irradiate the reflective member 3 with electromagnetic waves and receive reflected waves from the reflective member 3. For example, the first radar device 21 may be placed on a wall 52 or ceiling 53, the second radar device 22 may be placed on a chair 54 or lighting 55, and the reflective member 3 may be placed on a blanket (not shown) that covers the subject.

[0107] With these configurations, it is possible to provide a bed 51 equipped with a biometric information detection device 1,1a that can obtain highly reliable human biological signals while suppressing an increase in the size of the biometric information detection device 1,1a and achieving miniaturization and cost reduction of the biometric information detection device 1,1a. Furthermore, by arranging the biometric information detection device 1,1a in a hospital room as described above, it can be used to detect the vital signs of patients and to monitor them.

[0108] The embodiments described above are provided to facilitate understanding of this disclosure and are not intended to limit the invention. This disclosure may be modified or improved without departing from its spirit, and equivalents thereof are included.

[0109] This disclosure may take the following configuration, as described above, or alternatively.

[0110] (1) A biological information detection device according to one aspect of the present disclosure comprises a reflective member that reflects electromagnetic waves and a radar device that detects biological signals of a human body, wherein the reflective member is positioned between the human body and the radar device, and the radar device comprises a transmitting unit that irradiates electromagnetic waves toward the human body and the reflective member, respectively, and a first receiving unit and a second receiving unit that receive the reflected waves of the electromagnetic waves, wherein the transmitting unit irradiates electromagnetic waves including a first directional polarization component and a second directional polarization component different from the first directional polarization component, the reflective member reflects the first directional polarization component contained in the electromagnetic waves irradiated from the transmitting unit and transmits or absorbs the second directional polarization component contained in the electromagnetic waves irradiated from the transmitting unit, the first receiving unit receives at least the first directional polarization component of the reflected waves reflected by the human body and the reflective member, and the second receiving unit receives the second directional polarization component of the reflected waves reflected by the human body.

[0111] In this configuration, the transmitting unit emits electromagnetic waves (transmitted signal) that include a first directional polarization component and a second directional polarization component different from the first directional polarization component. The reflecting member reflects the first directional polarization component contained in the electromagnetic waves emitted from the transmitting unit and transmits or absorbs the second directional polarization component contained in the electromagnetic waves emitted from the transmitting unit. The first receiving unit receives at least the first directional polarization component of the reflected waves reflected by the human body and the reflecting member, and the second receiving unit receives the second directional polarization component of the reflected waves reflected by the human body. With this configuration, the second directional polarization component of the reflected waves reflected by the reflecting member is suppressed. As a result, the accuracy of the signal calculated from the second directional polarization component of the reflected waves received by the second receiving unit can be improved.

[0112] (2) The biological information detection device described in (1) above comprises a displacement signal generation unit that generates a first displacement signal based on a reflected wave received by the first receiving unit and a second displacement signal based on a reflected wave received by the second receiving unit, and a biological signal generation unit that separates the first displacement signal from the second displacement signal and generates a biological signal of the human body.

[0113] In this configuration, the second directional polarization component of the reflected wave reflected by the reflective member is suppressed, and the accuracy of the second displacement signal generated based on the second directional polarization component of the reflected wave received by the second receiver can be improved. In other words, a second displacement signal with the influence of the reflected wave component from the reflective member suppressed can be obtained. Consequently, a highly reliable biosignal can be obtained.

[0114] (3) A biological information detection device according to one aspect of the present disclosure comprises a reflective member that reflects electromagnetic waves, a first radar device that irradiates the reflective member and the human body with electromagnetic waves polarized in a first direction and receives the reflected waves of said electromagnetic waves, and a second radar device that irradiates the reflective member and the human body with electromagnetic waves polarized in a second direction different from the first direction and receives the reflected waves of said electromagnetic waves, wherein the reflective member is positioned between the human body and the first radar device and reflects the electromagnetic waves polarized in a first direction irradiated from the first radar device and transmits or absorbs the electromagnetic waves polarized in a second direction irradiated from the second radar device.

[0115] In this configuration, the first radar device irradiates the reference surface of the reflective material and the subject's body surface with electromagnetic waves (transmitted signals) polarized in a first direction and receives the reflected waves. The second radar device irradiates the reflective material and the body with electromagnetic waves polarized in a second direction, different from the first direction, and receives the reflected waves. The reflective material reflects the electromagnetic waves polarized in a first direction irradiated from the first radar device and transmits or absorbs the electromagnetic waves polarized in a second direction irradiated from the second radar device. This configuration suppresses the reflected waves polarized in a second direction that are reflected by the reflective material. As a result, the accuracy of the signal calculated from the reflected waves polarized in a second direction transmitted and received by the second radar device can be improved.

[0116] (4) The biological information detection device described in (3) above comprises a displacement signal generation unit that generates a first displacement signal based on a reflected wave received by the first radar device and a second displacement signal based on a reflected wave received by the second radar device, and a biological signal generation unit that separates the first displacement signal from the second displacement signal and generates a biological signal of the human body.

[0117] In this configuration, the second directional polarization component of the reflected wave reflected by the reflective member is suppressed, thereby improving the accuracy of the second displacement signal generated based on the second directional polarization component of the reflected wave received by the second radar device. In other words, a second displacement signal with the influence of the reflected wave component from the reflective member can be obtained. Consequently, a highly reliable biosignal can be obtained.

[0118] (5) A vehicle in one aspect of this disclosure is equipped with the biometric information detection devices described in (1) to (4) above.

[0119] This configuration makes it possible to create a vehicle that can obtain highly reliable human biological signals while suppressing the expansion of the device size and achieving miniaturization and cost reduction.

[0120] (6) The bed in one aspect of this disclosure is equipped with the biometric information detection device described in (1) to (4) above.

[0121] This configuration allows for the miniaturization and cost reduction of the device by suppressing the expansion of the device size, while enabling the creation of a bed that can obtain highly reliable biological signals from the human body.

[0122] (7) A biological information detection method according to one aspect of the present disclosure includes: a first electromagnetic wave irradiation step of irradiating a human body with electromagnetic waves including a first direction polarization component and a second direction polarization component different from the first direction polarization component; a first reflected wave reception step of receiving a reflected wave of the second direction polarization component from the first direction polarization component and the second direction polarization component included in the electromagnetic waves irradiated in the first electromagnetic wave irradiation step; a second electromagnetic wave irradiation step of irradiating a reflective member that reflects electromagnetic waves with electromagnetic waves including a first direction polarization component and a second direction polarization component; a second reflected wave reception step of receiving a reflected wave of the first direction polarization component from the first direction polarization component and the second direction polarization component included in the electromagnetic waves irradiated in the second electromagnetic wave irradiation step; a displacement signal generation step of generating a second displacement signal from the reflected wave received in the first reflected wave reception step and generating a first displacement signal from the reflected wave received in the second reflected wave reception step; and a biological signal generation step of separating the first displacement signal from the second displacement signal generated in the displacement signal generation step and generating a biological signal of the human body.

[0123] In this configuration, in the first electromagnetic wave irradiation step, an electromagnetic wave (transmission signal) containing a first direction polarization component and a second direction polarization different from the first direction polarization component is irradiated toward the human body, and in the first reflected wave reception step, the reflected wave of the second direction polarization component from the first direction polarization component contained in the electromagnetic wave irradiated in the first electromagnetic wave irradiation step is received. In the second electromagnetic wave irradiation step, an electromagnetic wave containing a first direction polarization component and a second direction polarization component is irradiated toward the reflective member, and in the second reflected wave reception step, the reflected wave of the first direction polarization component from the first direction polarization component contained in the electromagnetic wave irradiated in the second electromagnetic wave irradiation step is received. Then, in the displacement signal generation step, a second displacement signal is generated from the reflected wave received in the first reflected wave reception step, and a first displacement signal is generated from the reflected wave received in the second reflected wave reception step, and in the biosignal generation step, the first displacement signal is separated from the second displacement signal generated in the displacement signal generation step to generate a biosignal of the human body. This configuration suppresses the second directional polarization component of the reflected wave reflected by the reflective member, thereby improving the accuracy of the second displacement signal generated based on the second directional polarization component of the reflected wave. In other words, it is possible to obtain a second displacement signal in which the influence of the reflected wave component from the reflective member is suppressed. Consequently, it is possible to obtain a highly reliable biosignal.

[0124] (8) A biological information detection method according to one aspect of the present disclosure includes: an electromagnetic wave irradiation step of irradiating a reflective member that reflects electromagnetic waves with electromagnetic waves polarized in a first direction and irradiating a human body with electromagnetic waves polarized in a second direction different from the first direction; a reflected wave reception step of receiving a reflected wave of the electromagnetic waves polarized in a first direction irradiated in the electromagnetic wave irradiation step and receiving a reflected wave of the electromagnetic waves polarized in a second direction irradiated in the electromagnetic wave irradiation step; a displacement signal generation step of generating a second displacement signal from the reflected wave polarized in a second direction received in the reflected wave reception step and generating a first displacement signal from the reflected wave polarized in a first direction received in the reflected wave reception step; and a biological signal generation step of separating the first displacement signal from the second displacement signal generated in the displacement signal generation step and generating a biological signal of the human body.

[0125] In this configuration, in the electromagnetic wave irradiation step, electromagnetic waves with a first direction polarization are irradiated toward the reflecting member, and electromagnetic waves with a second direction polarization different from the first direction polarization are irradiated toward the human body. In the reflected wave reception step, the reflected waves of the electromagnetic waves with the first direction polarization irradiated in the electromagnetic wave irradiation step are received, as well as the reflected waves of the electromagnetic waves with the second direction polarization irradiated in the electromagnetic wave irradiation step. Then, in the displacement signal generation step, a second displacement signal is generated from the reflected waves with the second direction polarization received in the reflected wave reception step, and a first displacement signal is generated from the reflected waves with the first direction polarization received in the reflected wave reception step. In the biosignal generation step, the first displacement signal is separated from the second displacement signal generated in the displacement signal generation step, and a biosignal of the human body is generated. With this configuration, the second direction polarization component of the reflected waves reflected by the reflecting member is suppressed, and the accuracy of the second displacement signal generated based on the second direction polarization component of the reflected waves can be improved. In other words, a second displacement signal can be obtained in which the influence of the reflected wave component from the reflecting member is suppressed. Ultimately, this allows us to obtain highly reliable biosignals.

[0126] This disclosure makes it possible to realize a biometric information detection device that can obtain highly reliable human biological signals while suppressing the expansion of the device size and achieving miniaturization and cost reduction, as well as a vehicle and bed equipped therewith, and a biometric information detection method. [Explanation of Symbols]

[0127] 1,1a Biometric information detection device 2. Radar equipment 2a RF signal generation section 2b Transmitter 2c1 First receiving unit 2c2 Second receiving unit 2d RF signal processing unit 2e arithmetic unit 2f Displacement signal generation unit 2g Biosignal Generation Unit 2h Biological Information Processing Unit 3 Reflective material 3a reflector 4 subjects 5 sheets 5a Internal material 5b Surface material 21. First Radar Device 21a RF Signal Processing Unit 22 Second Radar System 22a RF Signal Processing Unit 23 Arithmetic unit 23a Displacement signal generation unit 23b Biosignal generation unit 23c Biological Information Processing Unit 40 vehicles 51 beds

Claims

1. A biological information detection device for detecting biological signals of the human body, A reflective member that reflects a first directional polarization component contained in electromagnetic waves and transmits or absorbs a second directional polarization component different from the first directional polarization component, Radar equipment and, Equipped with, The radar device, A transmitting unit that irradiates electromagnetic waves including the first direction polarization component and the second direction polarization component toward the human body and the reflective member, respectively, A first receiving unit receives the reflected wave of the first directional polarization component among the first and second directional polarization components contained in the electromagnetic wave transmitted from the transmitting unit, A second receiving unit receives the reflected wave of the second polarized component among the first polarized component and the second polarized component contained in the electromagnetic wave transmitted from the transmitting unit, Equipped with, Based on the reflected wave received by the first receiving unit and the reflected wave received by the second receiving unit, the biological signals of the human body are detected. Biometric information detection device.

2. A biological information detection device according to claim 1, A displacement signal generation unit generates a first displacement signal based on the reflected wave received by the first receiving unit and generates a second displacement signal based on the reflected wave received by the second receiving unit, A biosignal generation unit separates the first displacement signal from the second displacement signal and generates the biosignal of the human body, Equipped with, Biometric information detection device.

3. A biological information detection device for detecting biological signals of the human body, A reflective member that reflects electromagnetic waves polarized in a first direction and transmits or absorbs electromagnetic waves polarized in a second direction different from the first direction polarization, A first radar device that irradiates the reflective member with electromagnetic waves polarized in a first direction and receives the reflected waves of the electromagnetic waves polarized in the first direction, A second radar device that irradiates the human body with electromagnetic waves polarized in a second direction and receives the reflected waves of the electromagnetic waves polarized in a second direction, Equipped with, Based on the reflected waves received by the first radar device and the reflected waves received by the second radar device, the biological signals of the human body are detected. Biometric information detection device.

4. A biological information detection device according to claim 3, A displacement signal generation unit generates a first displacement signal based on the reflected wave received by the first radar device and generates a second displacement signal based on the reflected wave received by the second radar device, A biosignal generation unit separates the first displacement signal from the second displacement signal and generates the biosignal of the human body, Equipped with, Biometric information detection device.

5. A biological information detection device according to any one of claims 1 to 4, vehicle.

6. A biological information detection device according to any one of claims 1 to 4, bed.

7. A first electromagnetic wave irradiation step involves irradiating the human body with electromagnetic waves containing a first direction polarization component and a second direction polarization component different from the first direction polarization component, A first reflected wave receiving step in which the reflected wave of the second directional polarization component is received from the first directional polarization component and the second directional polarization component contained in the electromagnetic wave irradiated in the first electromagnetic wave irradiation step, A second electromagnetic wave irradiation step involves irradiating a reflective member that reflects electromagnetic waves with electromagnetic waves including a first direction polarization component and a second direction polarization component, A second reflected wave receiving step in which, of the first and second polarized components contained in the electromagnetic wave irradiated in the second electromagnetic wave irradiation step, the reflected wave of the first polarized component is received. A displacement signal generation step which generates a second displacement signal from the reflected wave received in the first reflected wave reception step and generates a first displacement signal from the reflected wave received in the second reflected wave reception step, A biosignal generation step which separates the first displacement signal from the second displacement signal generated in the displacement signal generation step and generates the biosignal of the human body, Having, A method for detecting biometric information.

8. An electromagnetic wave irradiation step in which electromagnetic waves with a first direction polarization are irradiated toward a reflective member that reflects electromagnetic waves, and electromagnetic waves with a second direction polarization different from the first direction polarization are irradiated toward the human body, A reflected wave receiving step that receives the reflected waves of electromagnetic waves with a first direction polarization irradiated in the electromagnetic wave irradiation step, and also receives the reflected waves of electromagnetic waves with a second direction polarization irradiated in the electromagnetic wave irradiation step, A displacement signal generation step which generates a second displacement signal from the second directionally polarized reflected wave received in the reflected wave reception step, and generates a first displacement signal from the first directionally polarized reflected wave received in the reflected wave reception step, A biosignal generation step which separates the first displacement signal from the second displacement signal generated in the displacement signal generation step and generates the biosignal of the human body, Having, A method for detecting biometric information.

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