WO2018186108A1

WO2018186108A1 - Biological-related information measuring device

Info

Publication number: WO2018186108A1
Application number: PCT/JP2018/009370
Authority: WO
Inventors: 添田　薫; 良下北
Original assignee: アルプス電気株式会社; ジーニアルライト株式会社
Priority date: 2017-04-07
Filing date: 2018-03-12
Publication date: 2018-10-11
Also published as: JP2020096648A

Abstract

This biological related information measuring device is provided with: a light-emitting element for emitting measurement light of predetermined wavelength; a light receiving element for receiving return light of the measurement light; a volume pulse wave measuring unit for estimating a volume pulse wave on the basis of the light reception results by the light receiving element; a light emission control unit for causing the light-emitting element to emit the measurement light in a pulse form at each timing of a predetermined time interval; a determination unit for determining, as the return light of the measurement light, the light which is received by the light receiving element during a time period from a rising time to a falling time of each of the measurement light at each time when the measurement light is emitted at predetermined time intervals under the control of the light emission control unit; and a frequency filter which removes a low-frequency noise and a high-frequency noise from a pulse wave signal composed of an electric signal based on the light that has been determined to be the return light of the measurement light by the determination unit, and which generates a signal relating to the volume pulse wave. This biological-related information measuring device can estimate a volume pulse wave on the basis of light reception results.

Description

Biological information measuring device

The present invention relates to a living body related information measuring apparatus and a sensor mounting unit for estimating living body related information of a subject, particularly information related to a volume pulse wave.

The living body related information measuring device described in Patent Document 1 is a living body related information measuring device that is worn on a user's body and measures the user's biological information, and detects the user's pulse wave and outputs a pulse wave signal. A pulse wave detection unit that detects a user's body motion and outputs a body motion signal, a state evaluation unit that evaluates the degree of stability of the user's motion state based on the body motion signal, and a state evaluation A detection interval setting unit that sets a pulse wave detection interval based on the evaluation result of the unit. Thereby, when it is evaluated that the degree of stability of the user's exercise state is sufficiently high, it is possible to change the setting to increase the detection interval of the pulse wave signal, and thus it is possible to further reduce power consumption. It is said.

JP 2016-198193 A

In an apparatus (biologically related information measurement apparatus) that estimates information on the volume pulse wave of a subject using return light obtained by irradiating the subject with light, such as disclosed in Patent Document 1, ideally a blood vessel If the return light that has been transmitted through and reflected from the blood vessel can be received as it is, the information on the change in blood flow that flows through the blood vessel can be returned and accurately captured as the change in the amount of light. it can. However, in reality, the change in the amount of return light detected by the light receiving element due to various factors has information other than the change in blood flow. The return light received by the light receiving element is converted into an electric signal by the photoelectric conversion element, and a process for generating a signal related to the volume pulse wave from the electric signal or a signal based on the electric signal is performed. Also in the processing of the electrical signal after the photoelectric conversion, various disturbance signals may be superimposed, and when such a disturbance signal is superimposed, the reliability of information regarding the finally estimated volume pulse wave is lowered.

In view of the current situation, the present invention has an object to provide a living body related information measuring apparatus that has a light emitting element and a light receiving element and estimates a volume pulse wave based on a light reception result.

In one aspect, the present invention provided to solve the above-described problems is a light-emitting element that emits measurement light having a predetermined wavelength, a light-receiving element that receives return light through the subject, and the light-receiving element. A volume pulse wave measurement unit that estimates a volume pulse wave of blood flowing through the blood vessel of the subject based on a light reception result by the element, and causes the measurement light to be emitted in a pulse form from the light emitting element at each time of a predetermined time interval A light emission control unit, and the light reception in a time period from a rising time to a falling time of the measurement light at each time when the measurement light is emitted at the predetermined time interval under the control of the light emission control unit. A pulse wave composed of a determination unit that determines that the light received by the element is the return light of the measurement light, and an electric signal based on the light that is determined by the determination unit to be the return light of the measurement light A frequency filter that generates a signal related to the volume pulse wave by removing signal components in a frequency band other than the frequency band corresponding to the heartbeat of the subject from the signal, and estimates information related to the volume pulse wave This is a living body related information measuring device.

The measurement light emitted from the light emitting element returns to the light receiving element via the inside of the subject as light. As described above, not only information relating to blood flow but also various information can be superimposed on the return light. In particular, in order to obtain information on the volume pulse wave, it is necessary to accurately measure the shape of the volume pulse wave. One factor that reduces the accuracy of the amount of light received by the light receiving element is that light other than the light derived from the measurement light emitted from the light emitting element is misidentified as returning light. Therefore, a measuring unit is provided to determine the light received in the time zone in which the pulsed measurement light is emitted (the time zone from the rise time to the fall time of the measurement light) as return light, The possibility of misrecognizing light other than light originating from as return light is reduced. A pulse wave signal having information related to the pulse wave is obtained by arranging in time series the electric signals obtained by photoelectrically converting the return light received in the time zone set by the determination unit in this way. Since this pulse wave signal is an aggregate of a plurality of pulse-shaped electric signals, these electric signals are digitized, and digital-analog conversion is performed on the obtained digital data signal to thereby relate to the volume pulse wave. A continuous electrical signal (analog signal) with information is obtained. The analog signal includes noise (stray light and the like) superimposed in the state of return light before photoelectric conversion, noise superimposed in the process until the analog signal is formed, and the like. Therefore, by performing a frequency filter process that removes signal components in a frequency band other than the frequency band corresponding to the heart rate range of the subject from the analog signal, it is possible to generate a highly accurate signal related to the volume pulse wave. . The removal frequency band of the frequency filter is appropriately set according to the frequency band of the heart rate range of the subject. As a specific example, when the subject is a person, it is possible to remove signal components in a frequency band of less than 0.6 Hz and a frequency band of more than 3.3 Hz.

In the above measurement apparatus, it is preferable that the signal relating to the volume pulse wave generated in the frequency filter includes information relating to overlapping notches of the volume pulse wave. If the signal related to the volume pulse wave contains information related to the overlapping notch, the signal related to the volume pulse wave can be used to confirm the boundary time between the systole and the diastole of the heart. It becomes possible to grasp information more accurately.

It is preferable that the measurement apparatus includes a contact adjustment mechanism that adjusts a contact state with the subject. When the contact state with respect to the subject, that is, the mounting state of the measuring apparatus changes during measurement, the amount of return light received by the light receiving element may change greatly. Such a change in the amount of light adversely affects the reliability of the signal related to the volume pulse wave. Therefore, it is possible to improve the accuracy of the signal related to the volume pulse wave by suppressing the fluctuation of the contact state (the mounting state of the measurement device) with respect to the subject by the contact device including the contact adjustment mechanism.

The contact adjustment mechanism includes a mechanism that elastically presses the casing from the opposite side of the casing that holds the light receiving element and the light emitting element to the side of the subject. It is preferable.

It is preferable that the measurement apparatus includes a light shielding mechanism that prevents light other than the measurement light emitted from the light emitting element from entering the light receiving element. Although the possibility of receiving light other than the return light of the measurement light from the light emitting element by the light receiving element is reduced by the determination unit, if the light from the outside is superimposed in the time zone in which the measurement light is emitted, the return light There is a concern that the amount of light will change greatly. Therefore, by providing the light shielding mechanism as described above, the possibility that the light receiving element receives light other than return light other than measurement light can be more stably reduced. In addition, the member which comprises a light-shielding mechanism may comprise said contact adjustment mechanism.

According to another aspect of the present invention, in another aspect, using the biological related information measuring device, a step of obtaining a signal related to the volume pulse wave, a step of identifying the overlapping notch from the signal related to the volume pulse wave, And a step of estimating the open / closed state of the aortic valve of the subject's heart from the overlap notch. The plethysmogram obtained by the living body related information measuring device can appropriately have information on overlapping notches. Therefore, the open / closed state of the aortic valve of the heart can be appropriately estimated by specifying the overlapping notch from the obtained signal regarding the volume pulse wave.

According to the present invention, there is provided a measuring apparatus that estimates a volume pulse wave that is accurate and, in a preferred aspect, is accurate enough to confirm an overlapping notch based on a result of receiving a return light of measuring light emitted from a light emitting element. Provided.

[Correction based on Rule 91 19.03.2018]
(A), (b) is a perspective view which shows schematic structure of the biological body relevant information measuring apparatus which concerns on embodiment of this invention, (a) is the figure seen from the board | substrate side, (b) is light-receiving / emission. It is the figure seen from the surface side. It is a top view which shows the example of arrangement | positioning of the 1st light emission part, the 2nd light emission part, and a light-receiving part in the biological body relevant-information measurement apparatus which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view taken along line A′-A ′ of FIG. It is a block diagram which illustrates the composition of the sensor module in the embodiment of the present invention. It is a flowchart showing operation | movement of a determination part. (A) The figure which shows the measurement result of the volume pulse wave which concerns on a prior art, and (b) The figure which shows the measurement result of the volume pulse wave obtained by the biological body related information measuring device which concerns on embodiment of this invention. (C) It is a figure for demonstrating the characteristic of a volume pulse wave. It is a flowchart of the information processing method which concerns on one Embodiment of this invention. It is a figure for demonstrating the structure of the band with which the biological body relevant information measuring device which concerns on embodiment of this invention is equipped, (a) External view and (b) Sectional drawing of the AA line of Fig.7 (a) It is.

Hereinafter, a living body related information measuring device according to an embodiment of the present invention will be described in detail with reference to the drawings. In each figure, XYZ coordinates are shown as reference coordinates, and the XY plane is a plane orthogonal to the Z1-Z2 direction. In the following description, the state viewed along the Z1-Z2 direction with the Z1 direction as the upward direction and the Z2 direction as the downward direction may be referred to as a plan view. In the following description, the same members are denoted by the same reference numerals, and the description of the members once described is omitted as appropriate.

FIGS. 1A and 1B are perspective views showing a schematic configuration of a living body related information measuring apparatus 10 according to the present embodiment. 1A is a perspective view seen from the substrate 20 side, and FIG. 1B is a perspective view seen from the light receiving and emitting surface 10a side opposite to the substrate 20. FIG. FIG. 2 is a plan view showing an arrangement example of the first light emitting unit 11, the second light emitting unit 12, and the light receiving unit 13 in the living body related information measuring apparatus 10. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG.

The living body related information measuring device 10 is a device that is attached so as to be in close contact with a subject, for example, the skin of a human body, and measures information related to volume pulse waves as living body information. The living body related information measuring device 10 includes a sensor module 10m shown in FIG. The sensor module 10 m includes two light emitting

units

11 and 12 and a light receiving unit 13 provided on the upper surface 20 a (FIG. 3) of the substrate 20.

As shown in FIG. 3, each of the two light emitting

units

11 and 12 emits light I11 and I12 having a predetermined wavelength by turning on the light emitting elements 11a and 12a, respectively, and emits (emits) light toward the subject as measurement light. ) In the light receiving unit 13, the return light I13 emitted from the two light emitting

units

11 and 12 and passing through the subject is received by the light receiving element 13a. Here, the return light that has passed through includes light that has passed through the inside of the subject, for example, inside a blood vessel, light that has diffused inside, and light that has been reflected or diffused on the surface. The measurement lights I11 and I12 are emitted and the return light I13 is received by the light emitting / receiving surface 10a facing the substrate 20 in the Z1-Z2 direction. The living body related information measuring device 10 is mounted so that the light emitting / receiving surface 10a is in close contact with the subject. The details of the sensor module 10m having the two light emitting

units

11 and 12 and the light receiving unit 13 will be described later.

As shown in FIG. 2, the first light emitting unit 11, the light receiving unit 13, and the second light emitting unit 12 are sequentially arranged from the Y2 side to the Y1 side along the Y1-Y2 direction. The center distance between the plane center C11 of the first light emitting unit 11 and the plane center C13 of the light receiving unit 13 is the first distance L1, and the plane center C12 of the second light emitting unit 12 and the plane center C13 of the light receiving unit 13 are the same. The center distance is set to the second distance L2. The first distance L1 and the second distance L2 are most preferably the same distance, but the two distances L1 and L2 preferably satisfy the following expression (1).
0.7 ≦ L2 / L1 ≦ 1.3 (1)
The distances L1 and L2 are preferably in the range of 4 mm to 11 mm.

When the distances L1 and L2 satisfy the above formula (1) and / or the above range, the measurement light emitted from each of the two light emitting elements 11a and 12a reaches each measurement site of the subject. Variation in depth can be suppressed to a certain range, and measurement variation of biological information based on measurement light from these light emitting elements 11a and 12a (specifically, variation in shape of measured volume pulse wave) can be suppressed. .

As shown in FIGS. 1 and 3, the living body related information measuring apparatus 10 includes a housing 30 that holds the first light emitting unit 11, the second light emitting unit 12, and the light receiving unit 13. Specifically, the housing 30 is provided on the upper surface 20a (the surface facing the Z1 direction) of the substrate 20 by the adhesive layer 21. Further, the housing 30 has a first emission opening 31 provided in the emission path of the measurement light I11 from the first light emitting unit 11 and a second emission provided in the emission path of the measurement light I12 from the second light emission part 12. The light emitting opening 32 and the light receiving opening 33 provided in the light receiving path of the return light I13 in the light receiving unit 13 are provided. The first light emitting unit 11 is arranged in the first emission opening 31, the second light emitting unit 12 is arranged in the second emission opening 32, and the light receiving unit 13 is arranged in the light receiving opening 33. . The outgoing light from the first light emitting unit 11 travels into the first emission opening 31, and the outgoing light from the second light emitting unit 12 travels into the second emission opening 32.

The housing 30 is formed of a light shielding material, for example, metal or resin. By configuring the housing 30 with a light-shielding material, it is possible to prevent light emitted from the first light emitting unit 11 and the second light emitting unit 12 from directly entering the light receiving unit 13 without passing through the subject. Therefore, it becomes easy to accurately extract information necessary for measurement of biological information, and highly accurate measurement is possible. Further, when the casing 30 is made of a metal material, it can function as a heat radiating member that releases heat generated in the two light emitting

units

11 and 12 and the light receiving unit 13 to the outside. On the other hand, when the housing 30 is made of a resin material, the elasticity can be arranged along the shape of the skin as the subject, thereby improving the adhesion.

In the living body-related information measuring device 10, three

translucent members

41, 42, and 43 are provided so as to cover the upper portions of the first emission opening 31, the second emission opening 32, and the light receiving opening 33, respectively. It has been. The light emitted from the first light emitting unit 11 is emitted as measurement light from the inside of the first emission opening 31 through the translucent member 41 and is emitted to the outside on the upper side of the living body related information measuring device 10, and the second light emission. The light emitted from the unit 12 passes through the translucent member 42 from the second emission opening 32 as measurement light and is emitted to the outside on the upper side of the living body related information measuring device 10. The return light through which the measurement light passes through the subject passes through the translucent member 43, reaches the light receiving opening 33, and is received by the light receiving unit 13. For the

translucent members

41, 42 and 43, for example, PET (polyethylene terephthalate) is used. The three

translucent members

41, 42, 43 are fixed to the housing 30 by adhesion, and the

upper end surfaces

41a, 42a, 43a form the same surface as the light emitting / receiving surface 10a together with the upper surface 30a of the housing 30. . Thereby, the housing | casing 30 and the

translucent member

41,42,43 can be closely_contact | adhered to a subject simultaneously.

FIG. 4 is a block diagram illustrating the configuration of the sensor module 10m.
The sensor module 10 m includes a pair of light emitting

units

11 and 12, a light receiving unit 13, a control unit 14, and an input / output interface unit 15.

As shown in FIG. 4, the 1st light emission part 11 is provided with the 1st light emission element 11a, and the 2nd light emission part 12 is provided with the 2nd light emission element 12a. The emission wavelengths of the first light-emitting element 11a and the second light-emitting element 12a are not limited, but are preferably 500 nm or more and 1000 nm or less from the viewpoint of appropriately securing the amount of return light. As a specific example, the first light-emitting element 11a and the second light-emitting element 12a emit light containing near-infrared light of 600 nm to 804 nm, preferably 758 nm to 762 nm, as measurement light. The first light emitting element 11a and the second light emitting element 12a are light emitting diode elements or laser elements.

Each of the first light emitting unit 11 and the second light emitting unit 12 further includes a light emitting element that emits light having a wavelength region different from the emission wavelength of the first light emitting element 11a and the second light emitting element 12a as measurement light. May be. Specific examples of such an emission wavelength include near infrared light having a wavelength of 806 nm to 995 nm. Thus, by providing measurement light from the two light emitting elements 11a and 12a to the subject, information on the volume pulse wave can be measured, and biological information different from the volume pulse wave can be measured.

The light-receiving unit 13 is emitted from the first light-emitting unit 11 or the second light-emitting unit 12 and receives near-infrared light as return light that passes through the blood flowing through the blood vessel in the subject, in particular, the blood vessel, and converts it into an electrical signal. It has a light receiving element 13a. The light receiving element 13a is, for example, a photodiode. The light receiving element 13a has a sensitivity of outputting an electrical signal corresponding to the amount of received light.

It is preferable that the two light emitting

units

11 and 12 and the light receiving unit 13 are integrally configured as a light receiving and emitting unit. Further, the sensor module 10m may be a package of the two light emitting

units

11 and 12, the light receiving unit 13, the control unit 14, and the input / output interface unit 15.

The first light emitting unit 11 has a drive circuit 11b that drives the first light emitting element 11a, and the second light emitting unit 12 has a drive circuit 12b that drives the second light emitting element 12a. In addition, the light receiving unit 13 includes an amplification circuit 13b that amplifies a light reception signal output from the light receiving element 13a. These circuits 11b, 12b, and 13b may be constituted by one chip.

The control unit 14 is composed of a microcomputer. As the light emission control unit, the control unit 14 transmits a timing signal to each of the drive circuit 11b of the light emission unit 11 and the drive circuit 12b of the second light emission unit 12, and the first light emission unit 11 and the second light emission unit 12 are predetermined. Control to emit near-infrared light at the timing of. More specifically, the control unit 14 causes the first light emitting unit 11 and the second light emitting unit 12 to simultaneously emit light for a short time of about 200 to 600 microseconds at 10 millisecond intervals, for example. By controlling in this way, pulsed measurement light is continuously emitted from the first light emitting element 11a and the second light emitting element 12a.

The control unit 14 controls the measurement light at each time when the measurement light is emitted from the first light emitting element 11a and the second light emitting element 12a at a predetermined time interval (for example, every 10 milliseconds) under the control of the light emission control unit. There is a determination unit that determines that the light received by the light receiving element 13a in the time period from the rising time to the falling time (for example, the time period from 200 microseconds to 600 microseconds) is the return light of the measurement light.

The operation of the determination unit will be described in detail with reference to FIG. FIG. 5 is a flowchart showing the operation of the determination unit. First, the timing signal which the light emission control part which the control part 14 has transmits to each of the drive circuit 11b of the light emission part 11 and the drive circuit 12b of the 2nd light emission part 12 is confirmed (step S101). Then, each rise time of the measurement light is grasped, and it is determined whether or not the confirmed time is the rise time (step S102). When the confirmed time is the rise time or the time when the rise time has elapsed, the light received by the light receiving element 13a is determined as the return light of the measurement light, and after the amplification output from the amplifier circuit 13b of the light receiving unit 13 Is received in a memory (not shown) as a signal for generating a volume pulse signal (step S103). If the rise time has not been reached, the process returns to step S101 for checking the timing signal.

When the reception of the received light signal is completed in step S102, the timing signal is confirmed again (step S104), the respective falling times of the measurement light are grasped, and the confirmed time is the falling time or the time when the falling time has elapsed. It is determined whether or not (step S105). When the confirmed time is the falling time or the time when the falling time has elapsed, the amplified light reception signal output from the amplification circuit 13b of the light receiving unit 13 is used as a signal for generating a volume pulse wave signal. After capturing the data in the memory, one pulsed light reception signal corresponding to one pulse signal of the measurement light is obtained (step S106), and the process returns to step S101 where the timing signal is confirmed with respect to the rise time. If the fall time has not been reached, the process returns to step S105 where the timing signal is confirmed with respect to the fall time.

Thus, a plurality of pulsed light receiving signals are obtained corresponding to the continuous pulsed measurement light. Since the plurality of pulsed light receiving signals have information on time and the amount of light received by the light receiving element, a digital signal having information on pulse waves can be obtained by digitizing a group of pulsed light receiving signals. This digital signal is converted from digital to analog to generate an analog signal. For conversion to an analog signal, a conventionally known method such as linear interpolation may be used. This digital-analog conversion is also performed by the control unit 14.

As the frequency filter, the control unit 14 removes a signal component in a frequency band other than the frequency band corresponding to the heart rate of the subject from the analog signal, and generates a signal related to the volume pulse wave. The frequency band to be removed is appropriately set according to the heart rate range of the subject. Taking a case where the subject is a person as a specific example, the heart rate range of a person is generally 40 to 200 times per minute, and if this is set to a frequency range, 0.6 Hz to 3.3 Hz. Therefore, signal components in this frequency band are extracted, and signal components in other frequency bands (frequency bands consisting of less than 0.6 Hz and more than 3.3 Hz) are removed. By having such a frequency filter, low-frequency noise and high-frequency noise are appropriately removed, and a signal related to the volume pulse wave can be generated with high accuracy. As a low frequency noise source in the analog signal, the relative position between the external light source and the sensor module 10m changes due to the movement of the subject, or the mounting state of the sensor module 10m changes. A specific example is that the amount of received light changes. Specific examples of the high frequency noise source include noise generated from the control unit 14, noise from an electronic device carried by the subject, noise generated in processing such as digital-analog conversion, and the like.

In the above description, a digital signal obtained from a group of pulsed light reception signals is processed by a frequency filter on an analog signal obtained by digital-analog conversion. However, the present invention is not limited to this. You may process with a frequency filter with respect to a digital signal. An analog signal may be generated by performing digital-analog conversion on the obtained noise-removed digital signal.

FIG. 6A shows an analog signal generated by digital-analog conversion of the amplified received light signal output from the amplification circuit 13b of the light receiving unit 13, and is positioned as a conventional technique. The plurality of volume pulse waves shown in the display range of FIG. 6A are non-uniform in shape, and it is difficult to grasp the overlapping notch DN from each volume pulse wave. FIG. 6B illustrates a process of a determination unit performed on the amplified light reception signal output from the amplification circuit 13b of the light reception unit 13, and digital signals obtained from a plurality of obtained pulse signals are digital-analog. This is a volume pulse wave signal obtained by converting to generate an analog signal and subjecting the generated analog signal to processing of a frequency filter (transmission frequency band: 0.6 Hz to 3.3 Hz). The plurality of volume pulse waves shown in the display range of FIG. 6B have substantially similar shape characteristics, and the position of the overlapping notch DN can be specified for any signal.

FIG. 6C is a diagram for explaining the characteristics of the volume pulse wave. The plethysmogram rises sharply with the opening of the aortic valve (ascending leg AS), and an overlapping notch DN is formed in which the signal intensity varies greatly when the aortic valve is closed. After that, it will gradually descend. It is possible to estimate the open / close state of the aorta of the heart from the waveform of the volume pulse wave. As shown in FIG. 6 (c), the systolic and diastolic phases of the heart can be determined from the opening and closing times of the aorta, and the systolic and diastolic pressures can be measured based on these times. In addition, the mean arterial pressure can be calculated. The stroke volume can be estimated from the rise of the volume pulse waveform from the systolic force, the compliance of the artery, the area of the systole, and the like. This stroke volume is calculated from the hatched region R1 in FIG. These are very useful in anesthesia management because they can be measured continuously in real time. The control part 14 estimates the information relevant to a volume pulse wave as a volume pulse wave measurement part. At that time, the shape characteristic of the volume pulse wave including the overlapping notch DN as described above may be specified.

Therefore, it is possible to implement the information processing method described below using the living body related information measuring apparatus 10 according to the present embodiment. FIG. 7 is a flowchart of an information processing method according to an embodiment of the present invention.
As shown in FIG. 7, first, a process for obtaining a signal related to volume pulse wave using the living body related information measuring apparatus 10 according to the present embodiment is performed (step S111). In this step, the above-described determination unit processing and frequency filter processing are performed.

Next, a step of identifying the overlapping notch DN from the signal relating to the volume pulse wave thus obtained is performed (step S112). In the prior art, detailed investigations have been made on the waveform of the volume pulse wave. For example, a minute waveform called a precursor phase wave is generated before the ascending leg AS described above, a shock wave that is a peak portion of the volume pulse wave is generated immediately after the ascending leg AS, and thereafter, a double notch DN It is known that a peak lower than that of a shock wave called a tidal wave is generated up to and a double pulse is generated in the diastole after the overlapping notch DN. From the feature of the volume pulse wave, the position of the overlapping notch DN can be specified. Specifically, the position of the overlapping notch DN can be specified by performing primary differentiation or secondary differentiation on the volume pulse wave.

Thus, when the overlapping notch DN is specified, a process of estimating the open / closed state of the aortic valve of the subject's heart from the overlapping notch DN is performed (step S113). Specifically, the period from the initial rise of the ascending leg AS to the overlapping notch DN corresponds to the systole of the heart, and the period from the overlapping notch DN to immediately before the ascending leg AS of the next plethysmogram starts is dilated. It corresponds to the period. Information on the open / closed state of the aortic valve of the heart can be obtained from the relationship between the systolic area (region R1 in FIG. 6C) and the diastole area.

The control unit 14 may perform all of the information processing method described above for the living body related information measuring apparatus 10, or the living body related information measuring apparatus 10 performs only the step of acquiring the volume pulse wave (step S <b> 111), The signal related to the volume pulse wave obtained in step S111 is transmitted to an external device (for example, a smartphone) by the communication device included in the living body related information measuring apparatus 10, and the remaining steps (step S112 and step S113) are performed in the external device. May be.

In addition, the control unit 14 uses a built-in analog-digital conversion circuit as a living body related information measurement unit, and uses digital signal information that can process the amplified received light signal output from the amplification circuit 13b of the light receiving unit 13. And information (biological information) on blood passing through the blood vessel of the subject may be estimated based on the converted signal information. The biological information estimated by the control unit 14 includes changes in blood hemoglobin (Hb) in the measurement using the return light through which the near-infrared light emitted from the first light emitting element 11a and the second light emitting element 12a passes through the subject. Change amount), blood oxygen ratio change (oxygen level), and the like.

Here, the absorbances of oxygenated hemoglobin and deoxygenated hemoglobin are equal at a wavelength of 805 nm, the absorbance of oxygenated hemoglobin is greater than that of deoxygenated hemoglobin at a wavelength longer than 805 nm, and oxygen at a wavelength shorter than 805 nm. The absorbance of oxyhemoglobin is smaller than the absorbance of deoxygenated hemoglobin. Therefore, when near-infrared light having a wavelength of 804 nm or less emitted from the first light-emitting element 11a and the second light-emitting element 12a is given to the human body as the subject, the absorbance of deoxygenated hemoglobin can be measured preferentially. . Since deoxygenated hemoglobin tends to have a smaller change in absorbance with respect to elapsed time than oxygenated hemoglobin, the pulsation and volume pulse wave of the subject can be measured more accurately.

If each of the first light emitting unit 11 and the second light emitting unit 12 is further provided with a light emitting element that emits measurement light including near infrared light having an emission wavelength of 806 nm or more and 995 nm or less, Information obtained from blood passing through the blood flow, for example, pulsation of blood flow, blood flow rate, flow rate, etc. can be obtained. Furthermore, from the measurement result by the light containing near infrared light of 804 nm or less and the measurement result by the light containing near infrared light of 806 nm or more and 995 nm or less emitted from the two light emitting elements 11a and 12a, the blood oxygen ratio It is possible to derive changes (oxygen levels) or related information

FIG. 8 is a diagram for explaining the structure of a band as a contact adjusting mechanism and a light shielding mechanism. FIG. 8A is a diagram illustrating a state where the band is attached to the subject. FIG. 8B is a cross-sectional view taken along the line AA in FIG.

As shown in FIG. 8A, the subject MB (a human wrist is shown as a specific example in FIG. 8A) in the housing 30 included in the living body related information measuring apparatus 100 is opposed. A band 200 made of an elastic body (specifically, an elastic cloth) is positioned so as to cover the side opposite to the side to be performed. Each of the bands 200 has a structure in which an inner elastic cloth 210 and an outer elastic cloth 220 having light shielding properties are overlapped, and the casing 30 is placed in a space 200 </ b> C between the inner elastic cloth 210 and the outer elastic cloth 220. The first light emitting unit 11, the second light emitting unit 12, and the light receiving unit 13 incorporated in the housing 30 can face the subject MB through the opening 210A of the inner elastic cloth 210. In such a configuration, the outer elastic cloth 220 elastically presses the housing 30 from the side opposite to the side facing the subject MB to the subject MB. If the contact state with respect to the subject MB, that is, the mounting state of the biological related information measuring device 100 changes during measurement, the amount of return light received by the light receiving unit 13 may change greatly. Such a change in the amount of light adversely affects the reliability of the signal related to the volume pulse wave. Specifically, it becomes a low-frequency noise source that destabilizes the baseline. Since the biological related information measuring device 100 includes the band 200 as a contact adjustment mechanism, fluctuations in the contact state with respect to the subject MB (the wearing state of the biological related information measuring device 100) are suppressed, and the accuracy of the signal related to the volume pulse wave is suppressed. Can be increased.

In addition, although the possibility of receiving light other than the return light of the measurement light from the light emitting element by the light receiving element by the determination unit is reduced, when light from the outside is superimposed on the time zone in which the measurement light is emitted, There is concern that the amount of return light may change significantly. Since the band 200 is made of a light shielding material, it also has a function as a light shielding mechanism. Therefore, the band 200 can more stably reduce the possibility that the light receiving elements (the first light emitting element 11a and the second light emitting element 12a) of the living body related information measuring device receive light other than the return light other than the measurement light. Can do. As described above, the band 200 and the member that constitutes the light shielding mechanism and also the member that constitutes the contact adjustment mechanism are from the viewpoint of simplifying the structure by reducing the number of components of the living body related information measuring apparatus 100 as a whole. preferable.

Although the present embodiment and its application examples have been described above, the present invention is not limited to these examples. For example, those in which the person skilled in the art appropriately added, deleted, or changed the design of the above-described embodiments or application examples thereof, or combinations of the features of the embodiments as appropriate are also included in the present invention. As long as the gist is provided, it is included in the scope of the present invention.

For example, in the above description, the return light of the measurement light from the two light emitting elements (the first light emitting element 11a and the second light emitting element 12a) is received by the light receiving element 13a, but the number of light emitting elements is one. It may be three or more. There may be a plurality of light receiving elements. Further, when measuring a pulse wave, information from another sensor may be taken in and the operation of the determination unit may be determined. For example, a signal indicating that the measurement should not be continued is input from a sensor related to environmental information such as an outside air temperature / humidity sensor or an atmospheric pressure sensor, or a sensor related to other information related to the subject such as an electrocardiogram sensor, an electroencephalogram sensor, or a motion sensor. In this case, if the light reception signal is not taken in, the volume pulse wave can be estimated more accurately.

DESCRIPTION OF

SYMBOLS

10, 100 Living body related information measuring apparatus 10m Sensor module 10a Light receiving / emitting surface 11 1st light emission part 11a 1st light emission element 11b Drive circuit 12 2nd light emission part 12a 2nd light emission element 12b Drive circuit 13 Light reception part 13a Light reception element 13b Amplifier circuit 14 Control unit 15 Input / output interface unit 20 Substrate 20a Upper surface 21 of substrate 20 Adhesive layer 30 Housing 30a Upper surface 31 of housing 30 First emission opening 32 Second emission opening 33

Light receiving openings

41, 42, 43 Translucent 41a, 42a, 43a Upper end surfaces B1, B2 of

translucent members

41, 42, 43 Straight lines C11, C12, C13 Plane centers I11, I12 Measuring light I13 Return light L1, L2 Distance DN Overlapping notch AS Ascending leg R1 Area MB Subject 200 Band 210 Inner elastic cloth 220 Outer elastic cloth 21 The space between the openings 200C inner elastic cloth 210 and the outer elastic fabrics 220 A inner elastic fabric 210

Claims

A light emitting element that emits measurement light of a predetermined wavelength;
A light receiving element for receiving return light through which the measurement light passes through the subject;
A volume pulse wave measurement unit that estimates a volume pulse wave of blood flowing through the blood vessel of the subject based on a light reception result by the light receiving element;
A light emission control unit for emitting the measurement light in a pulse form from the light emitting element at each time of a predetermined time interval;
Light received by the light receiving element in the time period from the rising time to the falling time of the measurement light at each time when the measurement light is emitted at the predetermined time interval under the control of the light emission control unit A determination unit that determines that the measurement light is a return light;
A signal component in a frequency band other than the frequency band corresponding to the heartbeat of the subject is removed from a pulse wave signal composed of an electrical signal based on the light determined to be the return light of the measurement light by the determination unit. A frequency filter for generating a signal related to the volume pulse wave;
Having
A living body related information measuring apparatus for estimating information related to the volume pulse wave.
The biological related information measuring device according to claim 1, wherein the signal relating to the volume pulse wave generated in the frequency filter includes information relating to overlapping notches of the volume pulse wave.
The living body related information measuring device according to claim 1 or 2, further comprising a contact adjusting mechanism for adjusting a contact state with respect to the subject.
The contact adjustment mechanism includes a mechanism that elastically presses the casing from the opposite side of the casing that holds the light receiving element and the light emitting element to the side of the subject. The living body related information measuring device according to claim 3.
The living body related information measuring device according to any one of claims 1 to 4, further comprising a light blocking mechanism that prevents light other than the measurement light emitted by the light emitting element from entering the light receiving element.
Using the biological related information measuring device according to any one of claims 2 to 5 to obtain a signal related to the volume pulse wave;
Identifying the overlapping notch from the signal relating to the volume pulse wave;
Estimating the open / closed state of the aortic valve of the subject's heart from the overlap notch,
An information processing method characterized by comprising: