JP2012147924A - Biological information detector - Google Patents

Abstract

When a biological information detection device is mounted on a vehicle to detect a pulse wave of an occupant of the vehicle, the occupant's pulse wave can be accurately detected with a low amount of light while avoiding placing the burden on the occupant. To be detected.
A light emitting unit that irradiates a vehicle seat with irradiation light composed of near-infrared light having a predetermined wavelength toward a predetermined part of a seated person seated on the vehicle seat, and the light emitting unit 21 irradiates the vehicle seat. A light receiving unit 22 for receiving reflected light from at least a pulse portion in the epidermis at a predetermined part of the seated person and outputting a signal corresponding to the intensity of the received reflected light. The light receiving unit 22 is prevented from receiving the reflected light from the body surface at the predetermined part of the seated person of the irradiation light emitted from the light emitting unit 21 between the light emitting unit 21 and the light receiving unit 22 in the seat. The partition part 23 to provide is detected, and the pulse wave of the seated person is detected from the output signal of the light receiving part 22.
[Selection] Figure 3

Description

  The present invention belongs to a technical field related to a biological information detection apparatus configured to detect a pulse wave of a seated person seated on a vehicle seat.

  2. Description of the Related Art Conventionally, a biological information detection apparatus that detects biological information such as a subject's heart rate and blood pressure in a non-contact manner using near infrared light is known. For example, in Patent Document 1, a living body information detection apparatus reflects an emission source that emits near-infrared light toward a living body from a position away from the living body, and is reflected by the skin (pulse part) of the living body at a position away from the living body. A detector for detecting the intensity of the near-infrared light and an intensity distribution for a predetermined time from the detected intensity of the near-infrared light, and based on the obtained intensity distribution, a heartbeat and blood pressure of the living body Is calculated. Such a biological information detection device utilizes the property that near-infrared light is absorbed by hemoglobin (especially oxygenated hemoglobin) in the blood, and by increasing or decreasing the blood volume (that is, hemoglobin volume) associated with the heartbeat. Since the amount of light absorption changes, the heartbeat and blood pressure of the living body can be obtained from the change in the intensity of near infrared light detected by the photodetector.

JP-A-9-262213

  By the way, if the biological information detection device as described above is mounted on a vehicle and a pulse wave of an occupant (especially a driver) of the vehicle is detected, the physiological state (tension state or arousal) of the occupant from the pulse wave. For example, when it is estimated that the occupant is in a state of reduced wakefulness, the occupant is warned to improve safety. become.

  Here, when the biological information detection device is mounted on a vehicle, it is conceivable to use a non-contact type biological information detection device as in the above-described conventional example so as not to place a burden on the vehicle occupant. . That is, the irradiation light composed of near-infrared light is irradiated toward the seated person from a position away from the seated person seated on the vehicle seat, and the seated person of the irradiated light is positioned away from the seated person. And the pulse wave of the seated person is detected from the intensity of the received reflected light. Then, the physiological state and health state of the seated person (occupant) are estimated from the shape of the pulse wave and the like.

  However, if the light emitting unit that emits the irradiation light and the light receiving unit that receives the reflected light from the seated person are provided at positions away from the seated person, the amount of light emitted by the light emitting unit is increased. Even if the amount of irradiation light is increased, the light receiving unit is not limited to the reflected light of the irradiated light from the seated person's veins (arteries and veins). Since the reflected light from the surface is received or the ambient light around the light receiving part is received, the SN ratio of the output signal of the light receiving part is lowered, and the pulse wave of the seated person (occupant) can be detected accurately. There is a problem that you can not.

  The present invention has been made in view of such a point, and an object of the present invention is to install a biological information detection device in a vehicle and detect the occupant's pulse wave in the vehicle. An object of the present invention is to make it possible to accurately detect the pulse wave of an occupant with a low irradiation light amount while avoiding the burden of wearing.

  In order to achieve the above object, in the present invention, irradiation light composed of near-infrared light having a predetermined wavelength is applied to a predetermined part of a seated person seated on the vehicle seat and seated on the vehicle seat. A reflected light received from at least a pulse part in the epidermis of a predetermined part of the seated person of the light emitted from the light emitting unit and the vehicle seat and irradiated from the light emitting unit. In the vehicle seat, for a biological information detection device including a light receiving unit that outputs a signal corresponding to the intensity of the light and a pulse wave detection unit that detects the pulse wave of the seated person from the output signal of the light receiving unit. A partition between the light emitting unit and the light receiving unit that suppresses the reflected light from the body surface at a predetermined part of the seated person from being irradiated by the light emitting unit. Part is provided. .

  With the above configuration, if the light emitting unit and the light receiving unit are provided at a position corresponding to a predetermined part of the seated person in the vehicle seat, the light emitting unit and the light receiving unit are simply seated on the vehicle seat. It will be located in the vicinity of the predetermined part of the seated person. Here, the skin of the seat and the clothes of the seated person are interposed between the light emitting part and the light receiving part and the predetermined part of the seated person, but the transmittance of the near-infrared light to the fabric is 80% or more. High and there is no problem with their intervention. As described above, the light emitting unit and the light receiving unit are positioned in the vicinity of the predetermined part of the seated person, so that the seated person has a predetermined range (that is, a part corresponding to the position where the light emitting part and the light receiving unit are provided). The near-infrared light can be emitted with a low dose toward the light receiving portion, and the light receiving portion is hardly affected by ambient light around the light receiving portion. In addition, since a partition portion is provided between the light emitting portion and the light receiving portion in the vehicle seat, the reflected light reflected from the body surface at the predetermined part of the seated person is received by the irradiation light emitted from the light emitting portion. The light received by the light receiving unit is not received by the light receiving unit, and the reflected light reflected by the veins (arteries and veins) in the epidermis at a predetermined part of the seated person is received. As a result, the S / N ratio of the output signal of the light receiving unit is increased. Therefore, it becomes possible to accurately detect the pulse wave of the occupant with a low irradiation light amount.

  In the biological information detection apparatus, it is preferable that the light emitting unit, the light receiving unit, and the partition unit are provided in the vehicle seat in a state of being integrated as a photodetector.

  Accordingly, the light emitting part, the light receiving part, and the partition part can be easily incorporated into the vehicle seat, and the handleability before being incorporated into the vehicle seat is improved.

  It is preferable that the photodetector is provided on a seat cushion of the vehicle seat.

  As a result, the partition part can be brought into close contact with a predetermined part of the seated person only by the vehicle occupant sitting on the vehicle seat, and the partition part allows the irradiation light to be emitted at the predetermined part of the seated person. It is possible to more reliably suppress the reflected light from the body surface from being received by the light receiving unit.

  When the light detector is provided in a seat cushion of the vehicle seat, the light detector is the right or left buttocks or left and right thighs of the seated person in the seat cushion or left and right. It is preferable to be provided at a position corresponding to each of the buttocks and left and right thighs.

  Thereby, it becomes possible to make a partition part contact | adhere to a seated person's predetermined part still more reliably. Further, when the occupant moves one foot (right foot) in accordance with the pedal operation, the SN ratio of the output signal of the light receiving unit of the photodetector on the side (right side) corresponding to the foot decreases, but the other foot The SN ratio of the output signal of the light receiving unit of the side (left side) photodetector is kept high. Therefore, the pulse wave of the seated person can always be accurately detected regardless of the driving operation.

  It is preferable that the photodetector further includes an elastic body that biases at least the partition portion toward a predetermined portion of the seated person.

  By doing so, it becomes possible to make the partition portion more closely contact the predetermined part of the seated person.

  In the biological information detection apparatus, the partition portion is formed of a cylindrical member, the light emitting portion is disposed outside the cylindrical member, and the light receiving portion is disposed inside the cylindrical member. It is preferable.

  Thus, a plurality of light emitting portions can be provided outside the cylindrical member, and the amount of irradiation light can be made appropriate depending on the number of the light emitting portions. Moreover, the partition part comprised with the cylindrical member suppresses more reliably that the reflected light from the body surface in the predetermined | prescribed site | part of a seated person of the irradiation light irradiated from each light emission part is received by the light-receiving part. In addition, the light receiving unit is less susceptible to the influence of ambient light around the light receiving unit.

  In the biological information detection apparatus, the partition portion is formed of a cylindrical member, the light emitting portion is disposed inside the cylindrical member, and the light receiving portion is disposed outside the cylindrical member. It may be.

  As a result, a plurality of light receiving portions can be provided outside the cylindrical member, and the reflected light from the pulse portion of the irradiated light can be reliably received.

  In the biological information detection device, the partition portion is configured by a plate member having a plurality of holes extending in the thickness direction, and the light emitting portion is disposed inside a part of the plurality of holes, A configuration may be adopted in which the light receiving portion is disposed inside the remaining holes.

  As a result, the surface of the partitioning portion on the seated person side can be widened, and the partitioning portion can be brought into close contact with a predetermined portion of the seating person on a wide surface. In addition, by configuring the partition portion with a material having flexibility (for example, rubber material), it is possible to bring the entire surface of the partition portion on the seated person side into close contact with a predetermined portion of the seated person. Even if the partition portion is made of such a material, the partition portion only compresses and deforms in the thickness direction of the plate material, and unlike the case of compressing and deforming an elongated shape in the longitudinal direction, it buckles. There is no.

  In the biological information detection apparatus, the predetermined wavelength is preferably a wavelength of 820 nm or more and 900 nm or less.

  That is, when the predetermined wavelength is shorter than 820 nm, the oxygenated hemoglobin absorbance of near-infrared light is low. For this reason, the amount of change in the amount of reflected light received by the light receiving unit with respect to the change in blood flow associated with heartbeat. Becomes smaller. Also, when the wavelength is shorter than 820 nm and longer than 900 nm, the near-infrared light body tissue reflectance and transmittance are reduced, and therefore, the near-infrared light absorption in the body tissue is reduced. As the scattering increases, the amount of change in the amount of reflected light decreases with respect to the change in blood flow associated with the heartbeat. Therefore, the predetermined wavelength is preferably 820 nm or more and 900 nm or less, and within this range, an appropriate light amount change width can be obtained with respect to a change in blood flow accompanying heartbeat.

  As described above, according to the living body information detection apparatus of the present invention, the vehicle seat is provided with the light emitting unit, the light receiving unit, and the partition unit, so that the vehicle occupant is not burdened to install the device. In addition, the amount of light emitted from the light emitting unit can be reduced, and the SN ratio of the output signal of the light receiving unit can be increased, so that the pulse wave of the occupant can be accurately detected with a low amount of light emitted. Will be able to.

It is a top view which shows the vehicle seat provided with the photodetector of the biological information detection apparatus which concerns on embodiment of this invention. It is a side view of the said vehicle seat. It is the III-III sectional view taken on the line of FIG. It is a top view of the said photodetector. It is sectional drawing which shows typically the body tissue in the epidermis in a predetermined part of a seated person, a light emission part, a light-receiving part, and a partition part. A graph showing the relationship between the wavelength of near infrared light, the oxygenated hemoglobin absorbance of near infrared light, the body tissue reflectance of near infrared light, and the body tissue transmittance per cm thickness of near infrared light It is. It is a top view which shows the modification of a photodetector. It is a block diagram which shows the structure of a controller, and the flow of control. It is a figure which shows the example of a pulse wave.

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

  1 and 2 show a vehicle seat 1 (hereinafter simply referred to as a seat 1) provided with a photodetector 11 of a biological information detection apparatus according to an embodiment of the present invention. FIG. 1 is a plan view of the seat 1. FIG. 2 is a side view of the sheet 1. The seat 1 is a seat for a driver's seat of a vehicle, and includes a seat cushion 2, a seat back 3 supported at the rear end portion of the seat cushion 2 so as to be pivotable (reclinable), and the seat. And a headrest 4 attached to the upper end of the back 3. The seat cushion 2 is supported on the floor of the vehicle compartment of the vehicle via a front / rear slide mechanism (not shown). The light detector 11 is not limited to the driver seat, and may be another vehicle seat (for example, a passenger seat).

  The seat cushion 2 of the seat 1 or the front / rear slide mechanism has a seated person detector 41 (shown only in FIG. 8) for detecting that an occupant is seated on the seat 1 (a seated person is present on the seat 1). Is provided. The seated person detector 41 detects pressure applied to the seated person detector 41.

  In the present embodiment, four photodetectors 11 are disposed in the vicinity of the seating surface (upper surface) of the seat cushion 2 of the seat 1. Each photodetector 11 is provided at a position corresponding to each of the left and right buttocks and left and right thighs of the seated person.

  As shown in FIG. 3, each of the photodetectors 11 opens to the upper surface of the pad 5 at a position corresponding to the left and right hips and left and right thighs of the seated person in the pad 5 of the seat cushion 2. Arranged in the provided recess 5 a, the upper side of each photodetector 11 (the upper opening of each recess 5 a) is covered with a skin 6 that covers the pad 5. An elastic member 7 made of sponge is fixed to the bottom surface of each recess 5a, and the photodetector 11 is fixed to the upper surface of the elastic member 7. The elastic member 7 compresses and deforms when the occupant sits on the seat 1 to ensure cushioning properties, but is not necessarily required.

  As shown in FIGS. 3 and 4, each photodetector 11 is fixed to the upper surface of the case 12 via a screw and a case 12 having a substantially rectangular box shape in plan view with the upper side opened. And a lid member 13 for closing the opening. Four support columns 15 having a circular cross section for supporting the substrate 14 are fixed to the bottom surface of the case 12 so as to extend upward. The upper half portions of the four support pillars 15 have a smaller diameter than the lower half portion, and respectively penetrate through through holes formed in the four corner portions of the substrate 14. Projections 13a projecting downward are respectively provided at positions corresponding to the support columns 15 on the lower surface of the lid member 13, and the upper end portions of the upper half portions of the support columns 15 are fitted into the projections 13a. A mating hole is provided.

  The substrate 14 is supported so as to be movable in the vertical direction with respect to the upper half portions of the four support columns 15, and provided on the lower side of the substrate 14 around the upper half portions of the support columns 15. It is biased upward by the compression coil spring 16. Thus, the board | substrate 14 urged | biased to upper side contact | abuts to the lower surface of the protrusion part 13a, and cannot move any more upward. The biasing of the substrate 14 as described above is not always necessary, and the substrate 14 may be fixed to the support column 15.

  A light emitting unit 21, a light receiving unit 22, and a partition unit 23 are provided on the upper surface of the substrate 14. That is, the light emitting unit 21, the light receiving unit 22, and the partition unit 23 are provided on the seat cushion 2 in a state of being integrated as the photodetector 11.

  The light emitting unit 21 is to a predetermined part of a seated person seated on the seat 1 (a part corresponding to a position where the four photodetectors 11 are provided (in this embodiment, left and right buttocks and left and right thighs)). The irradiation light which consists of near infrared light of a predetermined wavelength toward is directed. In the present embodiment, the light emitting unit 21 is composed of LEDs, and a plurality of (in this embodiment, 12) light emitting units 21 are provided, and the plurality of light emitting units 21 surround one light receiving unit 22 in plan view. It is arranged. The plurality of light emitting units 21 pass through the plurality of light emitting unit holes 13 b provided in the lid member 13 so that the upper end of the light emitting unit 21 is positioned above the upper surface of the lid member 13. The irradiation light emitted from the light emitting unit 21 passes through the skin 6 of the seat cushion 2 and the clothes of the seated person, and a part of the passed irradiation light enters the skin of a predetermined part of the seated person, Reflected on the body surface at a predetermined part of the seated person. Since the transmittance of the irradiated light (near infrared light) to the fabric is as high as 80% or more, the skin 6 of the seat cushion 2 and the clothes of the seated person detect the pulse wave of the seated person as described later. Have little effect.

  The light receiving unit 22 receives reflected light from at least the pulse part 35 (artery 35a and vein 35b) (see FIG. 5) in the epidermis at a predetermined part of the seated person of the irradiation light emitted from the light emitting part 21. Thus, a signal corresponding to the intensity (light quantity) of the received reflected light is output. That is, as shown in FIG. 5, at least a part of the irradiation light that has entered the epidermis at a predetermined part of the seated person is reflected by the pulse part 35 (particularly, the artery 35a is preferable), and the light receiving part 22 Receive light. Since near-infrared light is absorbed by hemoglobin (particularly oxygenated hemoglobin) in blood, the amount of reflected light reflected by the pulse portion 35 varies depending on the increase / decrease in blood volume associated with heartbeat. Thereby, the output signal of the light-receiving part 22 changes with heartbeat. In the present embodiment, the light receiving unit 22 includes a phototransistor. This is because a special amplifier circuit is not required and a relatively large output can be obtained. In addition, it is preferable that the reflected light coming out from the inside of the epidermis at a predetermined part of the seated person is condensed by the collimator lens and received by the light receiving unit 22.

  Here, FIG. 5 schematically shows the body tissue in the epidermis at a predetermined part of the seated person, and in the order from the outside, the epidermis 31, the dermis 32, the fat 33, the muscle 34, and the bone 36 exist. In addition, the pulse part 35 (the artery 35a and the vein 35b) passes through the deep part.

  The wavelength of the irradiation light (the predetermined wavelength) is preferably 820 nm to 900 nm. That is, as shown in FIG. 6, when the predetermined wavelength is shorter than 820 nm, the oxygenated hemoglobin absorbance of near-infrared light is low. For this reason, the light receiving unit 22 responds to changes in blood flow accompanying heartbeat. The amount of change in the amount of reflected light received is reduced. Also, when the wavelength is shorter than 820 nm and longer than 900 nm, the near-infrared light body tissue reflectance and transmittance are reduced, and therefore, the near-infrared light absorption in the body tissue is reduced. As the scattering increases, the amount of change in the amount of reflected light decreases with respect to the change in blood flow associated with the heartbeat. Therefore, the predetermined wavelength is preferably 820 nm or more and 900 nm or less (preferable wavelength range shown in FIG. 6), and if it is within this range, an appropriate light amount change width with respect to a change in blood flow accompanying heartbeat is obtained. can get.

  The partition portion 23 is provided between the light emitting portion 21 and the light receiving portion 22 on the upper surface of the substrate 14, and the reflected light from the body surface at a predetermined portion of the seated person of the irradiation light emitted from the light emitting portion 21. Is suppressed from being received by the light receiving unit 22. In this embodiment, the partition part 23 is comprised with the resin-made cylindrical members (cylindrical member) so that between the some light emission part 21 and the one light-receiving part 22 may be partitioned off. That is, the plurality of light emitting units 21 are arranged so as to be arranged in the circumferential direction outside the cylindrical member, and the light receiving unit 22 is arranged inside the cylindrical member (center portion of the cylindrical member). . The partition portion 23 passes through the partition portion hole 13 c provided in the lid member 13 so that the upper end of the partition portion 23 is positioned above the upper surface of the lid member 13. Moreover, the upper end of the partition part 23 is located above the upper ends of the light emitting part 21 and the light receiving part 22 (on the side of the predetermined part of the seated person). By this and the board | substrate 14 being urged | biased by the compression coil spring 16 to the upper side (the said predetermined part side of a seated person), the partition part 23 closely_contact | adheres to the predetermined part of a seated person. Therefore, as shown in FIG. 5, the reflected light from the body surface of the irradiation light (see the broken arrow in FIG. 5) is blocked by the partition portion 23 and does not reach the light receiving portion 22, and the epidermis Reflected light from the internal body tissue (at least the pulse part 35) is received by the light receiving part. In addition, since the light receiving unit 22 is located inside the cylindrical member, the ambient light around the light receiving unit 22 is not received by the light receiving unit 22 when a seated person is present on the seat 1.

  As described above, since the substrate 14 (that is, the partition portion 23) is biased upward by the compression coil spring 16, at least the partition portion 23 (in this embodiment, the light emitting portion 21 and the light receiving portion 22). And the partitioning portion 23) constitutes an elastic body that urges the seated person toward the predetermined part. Note that, with the substrate 14 fixed to the support column 15, only the partition portion 23 may be supported so as to be movable in the vertical direction with respect to the substrate 14, and only the partition portion 23 may be biased upward.

  In each photodetector 11, the number and arrangement of the light emitting portions 21 and the light receiving portions 22, the shape of the partition portion 23, and the like are not limited to those described above. The number of the light emission parts 21 arrange | positioned on the outer side of the cylindrical member which comprises the partition part 23 may be how many, for example, one may be sufficient. Further, the number of the light receiving portions 22 arranged inside the cylindrical member may be two or more. Alternatively, one or a plurality of light emitting units 21 may be arranged inside the cylindrical member, and one or a plurality of light receiving units 22 may be arranged outside the cylindrical member. When the light receiving unit 22 is arranged outside the cylindrical member in this way, the light receiving unit 22 may be affected by the ambient light around the light receiving unit 22, but there is a seated person on the seat 1. Since the light receiving part 22 is located in the vicinity of the seated person, it is difficult to be influenced by the ambient light.

  Moreover, as shown in FIG. 7, the partition part 23 of each photodetector 11 is comprised with the board | plate material which has the several hole 23a (through-hole) extended in the thickness direction, and this partition part 23 is the same in the thickness direction of a board | plate material. You may make it provide in the upper surface of the board | substrate 14 so that the surface of a side may face upwards (it faces the side of the predetermined part of a seated person). And the light emission part 21 is arrange | positioned inside the one part hole 23a among the some holes 23a, and the light-receiving part 22 is arrange | positioned inside the remaining hole 23a. In the example of FIG. 7, a plurality of holes 23a are arranged in 3 rows × 4 columns, and the light emitting portion holes 23a and the light receiving portion holes 23a are alternately arranged in each column and each row. . Further, one light emitting portion 21 or one light receiving portion 22 is disposed in each hole 23a.

  The partition portion 23 made of the plate material as described above is preferably made of a flexible material (for example, a rubber material). Thereby, when a seated person exists in the seat 1, the partition portion 23 is compressed and deformed in the thickness direction of the plate material, and the substantially entire surface of the seat portion side of the partition portion 23 is brought into close contact with a predetermined portion of the seated person. It will be possible to buckle at the time of compressive deformation.

  In the example of FIG. 7, the cross-sectional shape of each hole 23a is an octagonal shape. However, the present invention is not limited to this. For example, the cross-sectional shape of each hole 23a is a hexagonal shape, and the partition portion 23 has a honeycomb structure. Also good. Furthermore, the number of the light emitting parts 21 or the light receiving parts 22 arranged in each hole 23a may not be one, but may be plural.

  As shown in FIG. 8, the output signal of the light receiving unit 22 of each photodetector 11 is converted into a digital signal by an A / D converter (not shown) and input to the controller 51. The controller 51 is a control device based on a well-known microcomputer, and includes a central processing unit (CPU) that executes a program, a memory that is configured by, for example, a RAM or a ROM and stores programs and data, and various types. And an input / output (I / O) bus for inputting / outputting the above signals. The controller 51 includes a pulse wave detection unit 52, a seated person detection unit 53, a photodetector control unit 54, a pulse wave pattern analysis unit 55, an authentication unit 56, a health state estimation unit 57, a physiological state estimation unit 58, and a template. A management unit 59 is provided.

  An output signal (digital signal after conversion by the A / D converter) of the light receiving unit 22 of each photodetector 11 is input to the pulse wave detecting unit 52 of the controller 51, and the pulse wave detecting unit 52 is received by the light receiving unit 22. The pulse wave of the seated person is detected from the output signal. In addition, when the photodetector 11 provided with a plurality of light receiving units 22 exists, the output of the light receiving unit 22 of the photodetector 11 may be the sum of the outputs of the plurality of light receiving units 22, What is necessary is just to make it the average of the output of several light-receiving parts 22.

  Here, prior to the detection of the pulse wave, the pulse wave detection unit 52 calculates the amount of light received by the light receiving unit 22 from the output signal of the light receiving unit 22 of each photodetector 11 when the light emitting unit 21 emits the irradiation light. Measurement is performed, and information on the measurement result is transmitted to the photodetector control unit 54. Based on the information on the measurement result, the photodetector control unit 54 adjusts the amount of light emitted from the light emitting unit 21 of the photodetector 11 related to the measurement result or the light receiving sensitivity of the light receiving unit 22. In other words, depending on the clothes of the seated person, the sitting posture, etc., there is a possibility that an output signal suitable for pulse wave detection cannot be obtained due to a lack of the amount of irradiation light. Therefore, the photodetector control unit 54 adjusts the irradiation light amount or the light receiving sensitivity based on the output signal (that is, the light amount) so that the output signal of the light receiving unit 22 of each photodetector 11 is optimal for pulse wave detection. Thus, an optimum output signal is always obtained. This adjustment is performed after adjustment according to the physique described later.

  The seat occupant detection unit 53 receives pressure information from the seat occupant detector 41 and determines whether or not a seat occupant exists in the seat 1 from the measurement of the pressure, and the seat occupant exists. Information on the result of the determination (sitting determination) is transmitted to the photodetector control unit 54. Then, when the seat occupant detection unit 53 determines that a seat occupant is present on the seat 1, the light detector control unit 54 emits irradiation light toward a predetermined part of the seat occupant. On the other hand, the photodetector control unit 54 does not irradiate the irradiation light when the seated person detecting unit 53 determines that no seated person is present on the seat 1.

  In addition, the seated person detection unit 53 determines the physique of the seated person from the pressure information from the seated person detector 41 and transmits information on the result of the physique determination to the photodetector control unit 54. And the photodetector control part 54 receives the information of the said physique determination result, and adjusts the irradiation light quantity by the light emission part 21 of each photodetector 11 or the light reception sensitivity of the light-receiving part 22 according to this physique. For example, when the physique is large, it is considered that the fat 33 is thick, so that the pulse wave can be appropriately detected regardless of the physique by increasing the irradiation light quantity or increasing the light receiving sensitivity. A correspondence relationship is set in advance between the physique (pressure) and the irradiation light quantity or light receiving sensitivity, and is stored in the memory of the controller 51 as a map. The photodetector control unit 54 adjusts the irradiation light amount or the light receiving sensitivity from the physique (pressure) using the map representing the correspondence relationship. After the irradiation light amount or the light receiving sensitivity is adjusted according to the size of the seated person in this way, the photodetector control unit 54 adjusts the irradiation light amount or the light receiving sensitivity based on the measurement result information from the pulse wave detection unit 52 as described above. I do.

  As described above, the photodetector controller 54 controls the photodetector 11 (irradiation light irradiation and non-irradiation control by the light emitting unit 21 of the photodetector 11, control of the irradiation light amount by the light emitting unit 21, and Control of the light receiving sensitivity of the light receiving unit 22).

  After adjusting the irradiation light quantity or light receiving sensitivity by the above physique and light quantity measurement, the pulse wave detection unit 52 detects the seated person from the output signal of the light receiving part 22 when the light emitting part 21 emits irradiation light. Detect the pulse wave. In the present embodiment, the pulse wave detection unit 52 detects a pulse wave from the output signal of the light receiving unit 22 of each photodetector 11 (detects a pulse wave for each photodetector 11). Examples of pulse waves thus detected are shown in FIGS. 9 (a) and 9 (b). The shape of the pulse wave differs depending on the individual. The pulse wave shown in FIG. 9A is divided into two stages, and a small peak appears in the second stage. This is called a double wave in blood pressure pulse wave analysis and indicates peripheral vascular resistance. From this, in addition to the blood flow state, peripheral blood pressure fluctuations can be understood.

  The pulse wave pattern analysis unit 55 analyzes a pulse wave pattern for each pulse wave for each photodetector 11 detected by the pulse wave detection unit 52. Based on the pulse wave pattern analysis result, the authentication unit 56 performs personal authentication of the seated person, the health state estimating unit 57 estimates the health state of the seated person, and the physiological state estimating unit 58 includes the seating state. A person's physiological state (a tension state or a state of reduced alertness) is estimated.

  The template management unit 59 manages a template (pulse wave pattern) for performing personal authentication. That is, the template management unit 59 creates a template in advance from the pulse wave of the seated person detected by the pulse wave detection unit 52, and registers the created template in the storage device 43 provided in the vehicle. In the present embodiment, the creation and registration of the template is performed by a request (switch operation or the like) of the seated person (usually the owner of the vehicle) when the seated person is not driving, and the seated person is in a resting state. A template is created from the detected pulse wave. Whether or not the seated person is in a resting state is determined based on the result of the pulse wave pattern analysis, and if it can be considered that there is no change in the shape of the pulse wave for a predetermined time, the seated person is in a resting state. Determine and create a template from the pulse wave detected at this time (pulse wave detected from the output signal of the light receiving unit 22 of the photodetector 11 having the highest SN ratio of the output signal of the light receiving unit 22) and register it To do. It is also possible to create templates for a plurality of people and register them for each individual. The storage device 43 may be provided outside the vehicle. In this case, the controller 51 may be configured to be communicable with a server provided outside the vehicle, and the template may be registered in the storage device 43 via this server.

  In addition, when the authentication unit 56 performs personal authentication, the template management unit 59 reads a template from the storage device 43 and transmits the read template to the authentication unit 56. The authentication unit 56 compares the analysis result pattern of the pulse wave for each light detector 11 by the pulse wave pattern analysis unit with the template pattern registered in the storage device 43. It is determined (personal authentication) whether or not it is the same person as the person related to the template. This determination is preferably performed when the seated person is not driving and is in a resting state. Then, the determination result (authentication result) is output to the related device 44 (for example, an engine starting device or a navigation device). If the person is the same person, the seated person can operate the related device 44. The related devices 44 cannot be operated unless they are the same person.

  The health condition estimation unit 57 analyzes the pulse wave pattern of the pulse wave detected from the output signal of the light receiving unit 22 of the photodetector 11 having the highest SN ratio of the output signal of the light receiving unit 22 among the four photodetectors 11. The health status of the seated person is estimated from the pattern of the analysis result by the unit, and information on the estimated health status is output to the display 45 provided on the instrument panel. The display 45 receives the output and displays a warning when the health condition is abnormal. In the present embodiment, the health state estimation unit 57 determines that the pattern of the analysis result by the pulse wave pattern analysis unit of the pulse wave is clearly abnormal (for example, the person with the overlap wave exists, and the overlap wave sometimes disappears. In the case), information indicating an abnormality is output to the display 45.

  The physiological state estimation unit 58 analyzes the pulse wave pattern of the pulse wave detected from the output signal of the light receiving unit 22 of the photodetector 11 having the highest SN ratio of the output signal of the light receiving unit 22 among the four photodetectors 11. The physiological state of the seated person is estimated from the analysis result pattern by the unit, and information on the estimated physiological state is output to the display 45. The display 45 receives the output and displays a warning when the physiological state is abnormal (when it is in a state of reduced arousal). Moreover, in this embodiment, not only a warning display but a warning is given by giving a stimulus by a sound or a scent to a seated person in a state of reduced arousal.

  When the photodetector 11 having the highest SN ratio of the output signal of the light receiving unit 22 is specified, it is necessary to calculate the SN ratio. The calculation of the SN ratio is performed, for example, as follows. That is, in the case of a seated person who has been authenticated by the authentication unit 56, the pattern of the analysis result by the pulse wave pattern analysis unit of the pulse wave detected from the output signal of the light receiving unit 22 of each photodetector 11; For the seated person, the pattern of the template registered in the storage device 43 is compared, the amount of noise is obtained with reference to the template, and the SN ratio is calculated. Further, if the seated person is not authenticated by the authenticating unit 56, the pulse wave detected when the seated person is determined to be in a resting state is stored in the memory of the controller 51 as in the case of creating the template. The S / N ratio is calculated by obtaining the amount of noise based on the stored pulse wave. Note that the calculation of the S / N ratio is repeated every preset time (for example, a time including several pulse waves), and the photodetector 11 having the highest S / N ratio is specified for each calculation. It will be.

  As described above, among the four photodetectors 11, the health state of the seated person is determined from the pulse wave detected from the output signal of the light receiving unit 22 of the photodetector 11 having the highest SN ratio of the output signal of the light receiving unit 22. Alternatively, the physiological state is estimated when the seated person moves the body or moves one foot (right foot) in accordance with the pedal operation. 22 may output a signal containing a lot of noise, and it is impossible to accurately estimate the health state or physiological state of the seated person from the pulse wave detected from such an output signal. . By selecting the pulse wave detected from the output signal with the least noise, the health state or physiological state of the seated person can be estimated as accurately as possible.

  Next, the operation of the biological information detection apparatus will be described.

  When the seat occupant detection unit 53 of the controller 51 determines from the pressure input from the seat occupant detector 41 that there is no seat occupant on the seat 1, the light detector control unit 54 11 light emitting units 21 are deactivated so as not to be irradiated with irradiation light. At this time, the light receiving unit 22 of each photodetector 11 receives ambient light around the light receiving unit 22 and outputs a signal, but the pulse wave detection unit 52 of the controller 51 ignores the output signal.

  And if a passenger | crew sits on the sheet | seat 1 and the seated person detection part 53 determines with a seated person existing in the sheet | seat 1, the photodetector control part 54 will light-emitted by the light emission part 21 of all the photodetectors 11. FIG. Start irradiation. At this time, the photodetector control unit 54 adjusts the amount of light emitted by the light emitting unit 21 of each photodetector 11 or the light receiving sensitivity of the light receiving unit 22 based on the physique determination result by the seated person detecting unit 53. The irradiation of the irradiation light is continued until the seated person detecting unit 53 determines that no seated person is present on the seat 1.

  After the start of the irradiation of the irradiation light, the light receiving unit 22 of each photodetector 11 receives the reflected light of the irradiation light from at least the pulse part 35 in the epidermis at the predetermined part of the seated person. A signal corresponding to the intensity (light quantity) of the reflected light is output. Then, the pulse wave detection unit 52 measures the amount of light received by the light receiving unit 22 from the output signal of the light receiving unit 22 of each photodetector 11, and transmits information of the measurement result to the photodetector control unit 54. . Based on the information of the measurement result, the photodetector control unit 54 adjusts the irradiation light amount or the light receiving sensitivity so that the output signal of the light receiving unit 22 of each photodetector 11 is optimal for pulse wave detection.

  After the adjustment of the irradiation light amount or the light receiving sensitivity, the pulse wave detection unit 52 detects the pulse wave of the seated person from the output signal of the light receiving unit 22 of each photodetector 11, and the detected pulse wave is converted into a pulse wave. It transmits to the pattern analysis part 55. The pulse wave pattern analysis unit 55 analyzes the pulse wave pattern from the detected pulse wave. Based on the pulse wave pattern analysis result, the authentication unit 56 performs personal authentication of the seated person, The authentication result is output to the related device 44. In addition, the health state estimation unit 57 estimates the health state of the seated person, and the physiological state estimation unit 58 estimates the physiological state of the seated person (a tension state or a state of reduced arousal). Further, if there is a request from the seated person, the template management unit 59 creates a template from the pulse wave detected when the seated person is determined to be in a resting state, and the created template is stored in the storage device 43. sign up.

  In the present embodiment, since the photodetector 11 (the light emitting unit 21, the light receiving unit 22, and the partition unit 23) is provided on the seat cushion 2 of the seat 1, the occupant (seat occupant) only sits on the vehicle. ) Can be detected, and there is no burden on the occupant when wearing the device. Further, since the light emitting unit 21 and the light receiving unit 22 are located in the vicinity of the predetermined part of the seated person, the near infrared light can be irradiated with a low irradiation amount toward a narrow range that is the predetermined part of the seated person. At the same time, the light receiving unit 22 is less susceptible to ambient light around the light receiving unit 22. In addition, since the partition portion 23 is provided between the light emitting portion 21 and the light receiving portion 22 in the seat cushion 2, the reflected light reflected by the body surface at a predetermined part of the seated person is received by the light receiving portion 22. There is nothing. As a result, the SN ratio of the output signal of the light receiving unit 22 is increased. Therefore, it becomes possible to accurately detect the pulse wave of the occupant with a low irradiation light amount.

  The present invention is not limited to the embodiment described above, and can be substituted without departing from the spirit of the claims.

  For example, in the above embodiment, the photodetector 11 is provided at a position corresponding to the left and right buttocks and left and right thighs of the seated person in the seat cushion 2 of the seat 1. 2 may be provided at positions corresponding to the left and right buttocks of the seated person, or may be provided at positions corresponding to the left and right thighs, respectively, and the seat back 3 of the seat 1 (for example, corresponding to the waist of the seated person). It is also possible to irradiate irradiation light toward a predetermined part (for example, the waist) of the seated person.

  Moreover, in the said embodiment, although the light emission part 21, the light-receiving part 22, and the partition part 23 were provided in the seat cushion 2 of the sheet | seat 1 in the state integrated as the photodetector 11, respectively, the seat cushion 2 or It is also possible to provide the seat back 3 at a position corresponding to a predetermined part of the seated person. In this case, it suffices that only the partition portion 23 is urged toward the predetermined part of the seated person by an elastic body such as a spring.

  The above embodiments are merely examples, and the scope of the present invention should not be construed in a limited manner. The scope of the present invention is defined by the scope of the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention is useful for a biological information detecting device that detects a pulse wave of a seated person seated on a vehicle seat, and in particular, the pulse wave can be used to authenticate the seated person, This is useful when estimating a physiological state.

DESCRIPTION OF SYMBOLS 1 Vehicle seat 2 Seat cushion 11 Optical detector 16 Compression coil spring (elastic body)
DESCRIPTION OF SYMBOLS 21 Light emission part 22 Light reception part 23 Partition part 35 Pulse part 41 Seated person detector 51 Controller 52 Pulse wave detection part 53 Seated person detection part 54 Photodetector control part 56 Authentication part 57 Health condition estimation part 58 Physiological state estimation part 59 Template Management Department

Claims (9)

A light-emitting unit that is provided on the vehicle seat and irradiates irradiation light composed of near-infrared light of a predetermined wavelength toward a predetermined portion of a seated person seated on the vehicle seat;
The reflected light provided on the vehicle seat receives light reflected from at least a pulse portion in the epidermis at a predetermined part of the seated person and irradiated according to the intensity of the received reflected light. A light receiving unit that outputs a signal,
A biological information detection device comprising: a pulse wave detection unit that detects a pulse wave of the seated person from an output signal of the light receiving unit;
Reflected light from the body surface at a predetermined part of the seated person is received by the light receiving unit between the light emitting unit and the light receiving unit in the vehicle seat. A biological information detection device, characterized in that a partition portion for suppressing this is provided. The biological information detection apparatus according to claim 1,
The living body information detecting device, wherein the light emitting unit, the light receiving unit, and the partition unit are provided in the vehicle seat in a state of being integrated as a photodetector. The biological information detection apparatus according to claim 2,
The biological information detection apparatus according to claim 1, wherein the photodetector is provided on a seat cushion of the vehicle seat. The biological information detecting apparatus according to claim 3,
The photodetector is provided in the seat cushion at a position corresponding to each of the left and right buttocks or left and right thighs of the seated person, or left and right buttocks and left and right thighs. Biological information detection device. In the living body information detecting device according to any one of claims 2 to 4,
The above-mentioned photodetector further has an elastic body which urges at least the above-mentioned partition part to the above-mentioned predetermined part side of the seated person, The living body information detecting device characterized by things. In the living body information detection device according to any one of claims 1 to 5,
The partition part is composed of a cylindrical member,
The light emitting unit is disposed outside the cylindrical member,
The living body information detecting apparatus, wherein the light receiving unit is disposed inside the cylindrical member. In the living body information detection device according to any one of claims 1 to 5,
The partition part is composed of a cylindrical member,
The light emitting part is disposed inside the cylindrical member,
The living body information detecting apparatus, wherein the light receiving part is disposed outside the cylindrical member. In the living body information detection device according to any one of claims 1 to 5,
The partition portion is composed of a plate material having a plurality of holes extending in the thickness direction,
The living body information detecting apparatus characterized in that the light emitting part is disposed inside a part of the plurality of holes, and the light receiving part is disposed inside the remaining holes. . In the living body information detection device according to any one of claims 1 to 8,
The biological information detection apparatus, wherein the predetermined wavelength is a wavelength of 820 nm to 900 nm.

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