JP6661728B2 - Biological information acquisition device and watch terminal - Google Patents

Description

  The present invention relates to a biological information acquisition device and a wristwatch terminal, and more particularly to a biological information acquisition device and a wristwatch terminal that derive a pulse wave of a living body based on a detection signal obtained by irradiating a living body with light.

  When a living body is irradiated with light having a predetermined wavelength, the light is scattered (reflected / transmitted) on the epidermis, dermis surface, peripheral blood vessels, fat, arteries and the like of the living body. Since the pulse of the blood vessel moves periodically within a certain period of time, the corresponding periodic movement can be observed from the obtained reflected light or transmitted light transmitted through the living body. Therefore, in recent years, pulse waves have been measured by analyzing such reflected light and transmitted light.

  Here, in Patent Document 1, in order to remove body motion noise, light having a shorter wavelength than near-infrared light is applied to a living body from a detection signal of the amount of light reflected by a blood vessel obtained by irradiating near-infrared light to the living body. There has been disclosed a technique for deriving a pulse wave by reducing a detection signal of the amount of reflected light on the skin surface obtained by irradiation.

JP 2002-369805 A

  The technique of Patent Literature 1 is devised so that body motion noise can be removed. However, the body motion noise is only 4 to 5% of the total noise added to the pulse wave, and the body motion noise is removed. However, the accuracy of pulse wave measurement cannot be greatly improved.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a biological information acquisition device and a wristwatch terminal that can accurately measure a pulse wave.

The biological information acquisition device according to one embodiment of the present invention,
A first detection unit that irradiates a living body with light of a first wavelength and detects reflected light or transmitted light from the living body;
A second detection unit that irradiates the living body with light of a second wavelength to detect reflected light or transmitted light from the living body;
A pulse wave of the living body based on a subtraction value obtained by subtracting a detection signal obtained by irradiating the living body with the light of the second wavelength from a detection signal obtained by irradiating the living body with the light of the first wavelength. Processing unit to derive
Is provided.

The biological information acquisition method according to one embodiment of the present invention,
Irradiating a living body with light of a first wavelength to detect reflected light or transmitted light from the living body;
Irradiating the living body with light of a second wavelength to detect reflected light or transmitted light in the living body,
A pulse wave of the living body based on a subtraction value obtained by subtracting a detection signal obtained by irradiating the living body with the light of the second wavelength from a detection signal obtained by irradiating the living body with the light of the first wavelength. Steps to derive
Is provided.

The biological information acquisition device according to one embodiment of the present invention,
Board and
One of a light source and a light receiver provided on the substrate,
Provided on the substrate, a plurality of the other light source or the light receiver respectively disposed at least one each on a double or more concentric circles centered on one of the light source and the light receiver,
A processing unit that derives a pulse wave of the living body based on a detection signal of reflected light or transmitted light in the living body received by the light receiver,
Is provided.

  As described above, according to the present invention, it is possible to provide a biological information acquisition device and a wristwatch terminal that can accurately measure a pulse wave.

It is a block diagram showing typically the living body information acquisition device of a 1st embodiment. It is a top view showing typically a sensor unit in a living body information acquisition device of a 1st embodiment. It is a figure which shows typically signs that the light emitted from the light source in the biological information acquisition apparatus of 1st Embodiment is received by the light receiver via a living body. It is a flow chart figure showing a living body information acquisition method of a 1st embodiment. It is a figure which shows the light emission timing of red light or infrared light, and green light. FIG. 4 is a diagram illustrating different light emission timings of red light or infrared light and green light. FIG. 4 is a diagram exemplarily illustrating a detection signal of a first detection unit input to the processing device. FIG. 9 is a diagram illustrating an example of a waveform of a subtraction value obtained by subtracting a detection signal of a second detection unit from a detection signal of a first detection unit, and illustrating an example of a subtraction value and a feature point extracted from the subtraction value. It is a figure for deriving the blood pressure of a living body based on the extracted feature point and the regression line. It is a figure which shows the sensor unit of 2nd Embodiment typically. It is a figure showing typically the sensor unit of a 3rd embodiment. It is a figure showing typically the sensor unit of a 4th embodiment. It is a figure which shows the sensor unit of 5th Embodiment typically. It is a figure showing typically the sensor unit of a 6th embodiment. FIG. 3 is a diagram schematically illustrating a sensor unit configured to detect a contact pressure of a first light source with a living body. It is a figure which shows typically the structure which can adjust the contact pressure with respect to the living body of a 1st light source to the value set beforehand.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. In addition, in order to clarify the description, the following description and drawings are simplified as appropriate.

<First embodiment>
First, a biological information acquiring apparatus and a biological information acquiring method according to the present embodiment will be schematically described. The biological information acquiring apparatus and the biological information acquiring method according to the present embodiment use a first signal based on a detection signal (that is, an output waveform) of reflected light or transmitted light from a blood vessel obtained by irradiating a living body with light having a first wavelength. A pulse wave of a living body is obtained based on a subtraction value obtained by subtracting a detection signal of reflected light or transmitted light near the dermis, which is large as noise, obtained by irradiating the living body with light of the second wavelength. As a result, a detection signal with less noise can be obtained, and the pulse wave of the living body and thus the blood pressure of the living body can be accurately measured.

  Next, the biological information acquiring apparatus according to the present embodiment will be described in detail. FIG. 1 is a block diagram schematically illustrating the biological information acquisition device according to the present embodiment. FIG. 2 is a plan view schematically showing a sensor unit in the biological information acquiring device according to the present embodiment. FIG. 3 is a diagram schematically illustrating a state in which light emitted from a light source in the biological information acquisition device according to the present embodiment is received by a light receiver via a living body.

  The biological information acquiring device 1 is, for example, a biological information acquiring device provided in a wearable terminal, and is attached to a wrist or the like. As shown in FIG. 1, the biological information acquisition device 1 includes a sensor unit 10, an AFE (Analog Front End) 20, a processing device 30, and a display unit 40.

  The sensor unit 10 includes a first detection unit 11 and a second detection unit 12, and operates based on a control signal from the processing device 30. The first detection unit 11 receives a light source that emits red light or infrared light (IR: for example, a wavelength of 780 nm or more and 1100 nm or less) as detection light, and receives light reflected or transmitted by the detection light in a living body. It has a light receiver.

  The second detection unit 12 includes a light source that emits green light (for example, a wavelength of 495 nm or more and 570 nm or less) as detection light, and a light receiver that receives light that is reflected or transmitted by the detection light in a living body. .

  As the light source of the first detector 11 and the second detector 12, a light emitting element such as an LED (Light Emitting Diode) or an LD (Laser Diode) can be used. Light receiving elements such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal Oxide Semiconductor Image Sensor) can be used as the light receivers of the first detection unit 11 and the second detection unit 12. The photodetector photoelectrically converts a signal indicating the intensity of the received light and outputs the signal to the AFE 20.

  The sensor unit 10 according to the present embodiment irradiates the living body with red light or infrared light in the first detecting unit 11 to receive the reflected light reflected by the blood vessel, and outputs the green light in the second detecting unit 12 to the living body. And receives reflected light reflected by peripheral blood vessels, fat, and the like near the dermis.

  Specifically, as shown in FIG. 2, the sensor unit 10 includes a first light source 111 that emits red light or infrared light as detection light on a common substrate 13 and a second light source 111 that emits green light as detection light. , A third light source 122 that emits green light as detection light, and a light receiver 112. That is, the sensor unit 10 of the present embodiment includes one first detecting unit 11 and two second detecting units 12, and the light receiving units of the two second detecting units 12 are the first The light receiver 112 of the detection unit 11 is commonly used. Thus, the number of light receivers 112 can be reduced, and the size of the sensor unit 10 can be reduced.

  Here, the distance between the light receiver and the light source generally corresponds to the degree of penetration of light into the living body. Therefore, in the present embodiment, as shown in FIG. 3, the third light source 122, the second light source 121, and the first light source 111 are arranged in this order in a direction away from the light receiver 112, so that the living body can be moved from the dermis. The first light source 111 used to obtain the reflected light of the blood vessels existing inside the light source is located farther from the light receiver 112 than the second light source 121 and the third light source 122. Thereby, it is possible to satisfactorily receive the reflected light from the blood vessel. Incidentally, in FIG. 3, the light irradiation area is indicated by hatching. The intervals between the light sources 111, 121, and 122 are appropriately set based on the wavelength of the emitted light.

  In addition, the first light source 111, the second light source 121, and the third light source 122 of the present embodiment are arranged at substantially equal intervals on a substantially straight line as shown in FIG. This allows the first light source 111, the second light source 121, and the third light source 122 to be arranged on substantially the same blood vessel when the living body information acquisition device 1 is attached to a living body, and the measurement accuracy of the pulse wave is improved. Can be improved.

  The AFE 20 includes an amplifier 21, a noise removal filter 22, and an ADC (Analog Digital Converter) 23. The amplifier 21 amplifies the detection signal from the sensor unit 10. The noise removal filter 22 is an analog filter, and removes noise of the detection signal amplified by the amplifier 21 by analog processing. For example, the noise removal filter 22 is an LC filter such as a low-pass filter or a high-pass filter.

  The ADC 23 converts the detection signal from which noise has been removed by the noise removal filter 22 into a digital signal. Then, the ADC 23 outputs the detection signal converted into the digital signal to the processing device 30. The ADC 23 outputs a digital value sampled at a predetermined sampling cycle as a detection signal.

  The processing device 30 is, for example, a microcomputer, and includes a CPU (Central Processing Unit) 31, a memory 32, a digital filter 33, and a power management unit 34. The memory 32 stores a predetermined program. The CPU 31 reads out a program stored in the memory 32 and executes the program. By doing so, the processing device 30 measures the blood pressure (SBP, DBP) and the like based on the detection signal from the AFE 20, and outputs a signal indicating the measured blood pressure and the like to the display unit 40. Note that the processing device 30 may measure a health index other than the blood pressure, for example, an AI (arteriosclerosis index) value.

  The digital filter 33 subtracts the detection signal obtained by irradiating the living body with the detection light from the second light source 121 or the third light source 122 from the detection signal obtained by irradiating the living body with the detection light from the first light source 111. Perform processing. Here, since the pulse wave corresponding to the pulsation of the blood vessel repeatedly appears in the detection signal, the pulse wave of the living body can be obtained based on the detection signal.

  The power management unit 34 controls power supplied to the sensor unit 10. For example, the power management unit 34 supplies a predetermined drive current to each of the light sources 111, 121, and 122 to cause each of the light sources 111, 121, and 122 to emit light at a predetermined intensity. Further, the power management unit 34 may control the timing of supplying a current to each of the light sources 111, 121, and 122 so that the light sources 111, 121, and 122 emit light intermittently at a predetermined timing.

  The display unit 40 outputs information such as the pulse wave and blood pressure of the living body indicated by the signal from the processing device 30. As the display unit 40, for example, a liquid crystal display or an EL (Electro Luminescence) display can be used.

  Next, a biological information acquiring method using the above-described biological information acquiring device 1 will be described. Note that the biological information acquisition method of the present embodiment measures blood pressure based on a pulse wave of a living body. Here, FIG. 4 is a flowchart illustrating the biological information acquiring method according to the present embodiment. FIG. 5 is a diagram showing emission timings of red light or infrared light and green light. FIG. 6 is a diagram illustrating different light emission timings of red light or infrared light and green light. FIG. 7 is a diagram exemplarily illustrating a detection signal of the first detection unit input to the processing device. FIG. 8 illustrates an example of a waveform of a subtraction value obtained by subtracting the detection signal of the second detection unit from the detection signal of the first detection unit, and illustrates an example of the subtraction value and a feature point extracted from the subtraction value. It is. FIG. 9 is a diagram for deriving the blood pressure of the living body based on the extracted feature points and the regression line.

  First, the biological information acquisition device 1 is attached to a wrist of a living body by using, for example, a band, and as shown in FIG. 4, the detection light of the first light source 111, the second light source 121, and the third light source 122 are respectively applied to the living body. The light is irradiated, and the light reflected from the living body is received by the light receiver 112 (S1).

  Specifically, based on a control signal from the processing device 30, the first light source 111, the second light source 121, the second light source 121, and the third light source 122 are not overlapped so that the light emission periods of the first light source 111, the second light source 121, and the third light source 122 do not overlap. The light source 121 and the third light source 122 emit light at a predetermined cycle for a predetermined period.

  In the present embodiment, the pulse wave of the living body is sampled in advance, and as shown in FIG. 5, first, the first light source 111 emits light for approximately one cycle of the pulse wave, and then the second light source 121 is turned on. Similarly, light is emitted for approximately one cycle of the pulse wave. Further, the third light source 122 emits light for approximately one cycle period of the pulse wave.

  In other words, the living body is irradiated with the first light source 111, the second light source 121, and the third light source 122 in order at approximately one cycle of the pulse wave. Thus, the living body can be irradiated with the first light source 111, the second light source 121, and the third light source 122, respectively, for a substantially equal period from when the intensity of the detection signal is substantially equal.

  However, the start point of one cycle may not be the minimum point of the pulse wave and is not particularly limited. Further, in the present embodiment, the first light source 111, the second light source 121, and the third light source 122 are respectively radiated within the entire period of one cycle. For example, as shown in FIG. The detection light of the first light source 111, the second light source 121, and the third light source 122 may be emitted intermittently at a period substantially equal to the pulse wave and for the same period. Thereby, the power consumption of the first light source 111, the second light source 121, and the third light source 122 can be suppressed. In addition, the order of light emission of the light sources is not particularly limited, as long as the first light source 111, the second light source 121, and the third light source 122 emit light in one set.

  As described above, red light and infrared light are reflected by blood vessels, and green light is reflected by peripheral blood vessels and fat near the dermis. Therefore, as shown in FIG. 3, the detection light emitted from the first light source 111 to the living body is reflected by the blood vessel, and the reflected light is received by the light receiver 112. The detection light emitted from the second light source 121 to the living body is reflected by peripheral blood vessels, fat, and the like near the dermis, and the reflected light is received by the light receiver 112. Further, the detection light emitted to the living body from the third light source 122 is reflected by peripheral blood vessels or fat near the dermis, and the reflected light is received by the light receiver 112. The light receiver 112 photoelectrically converts a signal indicating the intensity of the received light and outputs an analog signal to the AFE 20.

  Next, the AFE 20 processes the detection signal input from the sensor unit 10 (S2). Specifically, the amplifier 21 of the AFE 20 amplifies the detection signal input from the sensor unit 10 based on the control signal of the processing device 30. Then, the noise removal filter 22 of the AFE 20 removes noise by filtering the amplified detection signal based on the control signal of the processing device 30. Further, the ADC 23 of the AFE 20 digitally processes the detection signal from which noise has been removed based on the control signal of the processing device 30 and outputs the digitally processed detection signal to the processing device 30. For example, the ADC 23 of the AFE 20 outputs a detection signal of the first detection unit 11 having a waveform as shown in FIG.

  Next, the processing device 30 measures the blood pressure based on the detection signal input from the AFE 20 (S3). Between the epidermis and the blood vessels, there are peripheral blood vessels and fats near the dermis, and noise based on light reflected by such peripheral blood vessels and fats passes detection light from the first light source 111 to the living body. It is included in the detection signal of the reflected light obtained by irradiation.

  Therefore, the digital filter 33 of the processing device 30 converts the detection light from the second light source 121 or the third light source 122 from the detection signal of the reflected light obtained by irradiating the living body with the detection light from the first light source 111. A pulse wave of a living body is obtained based on a subtraction value obtained by subtracting a detection signal of reflected light obtained by irradiating the subject. Then, the digital filter 33 outputs a detection signal indicating the subtraction value (that is, a detection signal indicating the pulse wave of the living body) to the CPU 31.

  As a result, it is possible to obtain a detection signal in which noise caused by reflection of the detection light from peripheral blood vessels, fat, and the like near the dermis is successfully removed, and as a result, measurement accuracy of a pulse wave of a living body can be improved. it can.

  Moreover, based on the detection signal of the reflected light obtained by irradiating the living body with the detection light from the first light source 111, the reflected light obtained by irradiating the living body with the detection light from the second light source 121 or the third light source 122 is obtained. Since this is a simple process for reducing the number of detection signals, the processing load on the processing device 30 can be reduced.

  Here, in the present embodiment, a detection signal of reflected light obtained by irradiating the living body with the detection light from the second light source 121, and a reflected light obtained by irradiating the living body with the detection light from the third light source 122 Of the detection signals, the one having the higher detection signal intensity is selected, and the selected detection signal is subtracted from the detection signal of the reflected light obtained by irradiating the living body with the detection light from the first light source 111. Thereby, the pulse wave of the living body can be measured with higher accuracy.

  Next, the CPU 31 of the processing device 30 measures the blood pressure based on the detection signal input from the digital filter 33. Specifically, as shown in FIG. 8, the CPU 31 detects the detection light from the second light source 121 or the third light source 122 from the detection signal of the reflected light obtained by irradiating the living body with the detection light from the first light source 111. One period of the pulse wave is specified from the period in which the subtraction value obtained by subtracting the detection signal of the reflected light obtained by irradiating the living body with light is positive. In the following description, a pulse wave for one cycle is defined as one pulse wave. The CPU 31 sets the timing at which the subtraction value changes from negative to positive as the start point of one pulse wave. In FIG. 8, the lower part shows the pulse wave of the living body by the subtraction value, and the upper part shows an enlarged part of the ideal pulse wave of the living body.

  Then, the CPU 31 extracts a feature point of one pulse wave based on the subtraction value. For each pulse wave, the CPU 31 extracts, for example, a maximum value, a minimum value, a maximum value, a minimum value, an inflection point, and the like as feature points. The CPU 31 calculates the value of the feature point and the time from the waveform of the subtraction value. For example, the CPU 31 calculates a feature point by differentiating a pulse wave to obtain a velocity pulse wave or by differentiating twice to obtain an acceleration pulse wave.

  In FIG. 8, the first peak (maximum value) in one cycle is a systolic peak, and the second peak (maximum value) is a reflective peak. Further, the minimum value after the second peak becomes a notch indicating a boundary between systolic and diastolic. The time from the start point of one cycle to the systemic peak is defined as S.D. Time. Reflective peak is set to R.P. Time. The time from the start point of one cycle to the notch is defined as Notch Time. Further, the CPU 31 extracts a minimum value of one cycle as a feature point. As described above, the CPU 31 calculates values and times at a plurality of feature points. Further, in the present embodiment, the maximum value, the minimum value, and the like may be corrected based on the subtraction value at the notch.

  The CPU 31 calculates a feature amount from the values of a plurality of feature points included in one pulse wave and time. In this specification, the characteristic amount is a value for calculating the blood pressure (SBP, DBP), and is a value derived from the value of the characteristic point in one pulse wave and time. The feature amount can be calculated based on a preset calculation formula.

  Then, the CPU 31 converts the feature amount into a blood pressure. The CPU 31 converts the feature amount into a blood pressure value using the regression line. Here, as shown in FIG. 9, two regression lines are stored in the memory 32 to calculate SBP (systolic blood pressure: BP_MAX) and BP (diastolic blood pressure: BP_MIN). Then, the CPU 31 calculates a feature quantity for SBP and a feature quantity for DBP based on one pulse wave. Then, the CPU 31 calculates SBP and DBP from the two feature amounts using the regression line. In this way, the processing device 30 derives the blood pressure and outputs a signal indicating the blood pressure to the display unit 40. Incidentally, FIG. 9 shows a diagram for calculating BP_MAX on the right side, and a diagram for calculating BP_MIN on the left side.

  Note that the regression line is set using a plurality of measurement results obtained in advance. That is, for a plurality of persons to be measured, a feature amount is obtained by the biological information acquisition device according to the present embodiment, and a blood pressure value is measured by a conventional cuff type sphygmomanometer. Thus, a database in which the feature amounts and the blood pressure values are associated with each other is constructed. Then, a regression analysis is performed on the data stored in the database to obtain a regression line.

  Here, the regression line may be set for each gender and each age. For example, it may be set for each gender and age, such as men in their twenties, women in their twenties, men in their thirties, and women in their thirties. That is, a database may be constructed by acquiring data for each age and gender.

  Further, the CPU 31 may convert the feature amount into the blood pressure using a regression curve using not only a regression line but also a polynomial of second order or higher.

  Further, the CPU 31 may calculate the blood pressure based on a plurality of pulse waves. For example, the CPU 31 extracts a feature point for each of n (n is an integer of 2 or more) pulse waves and calculates a feature amount. As a result, the feature amount is calculated for each pulse wave, so that n feature amounts are calculated. Then, the CPU 31 converts the n feature amounts into blood pressure (SBP or DBP) using the regression line. Thereby, n blood pressure values are calculated. Then, the average value of the n blood pressure values can be used as the blood pressure. As described above, by calculating the characteristic amount based on the plurality of pulse waves, the measurement accuracy can be improved.

  Further, the blood pressure may be obtained excluding the maximum value or the minimum value of the n blood pressure values. For example, of the n blood pressure values, the average of (n-2) blood pressure values excluding the maximum value and the minimum value may be used as the blood pressure. Thereby, the measurement accuracy can be further improved.

  One pulse wave (one cycle) from which a feature point cannot be extracted may be excluded from the calculation of the blood pressure. For example, due to the influence of noise or the like, the maximum value and the minimum value required for calculating the feature value are buried in the noise, and if the calculation cannot be performed, the feature value cannot be calculated for the cycle. Therefore, it is preferable not to convert blood pressure for one pulse wave (one cycle) from which a feature point cannot be extracted. By doing so, the measurement accuracy of the blood pressure can be improved.

  As described above, the CPU 31 estimates the tendency of the rise and fall of the pulse wave based on the subtraction value, and estimates the maximum value, the minimum value, the maximum value, the minimum value, the inflection point, and the like as the feature points. Then, the CPU 31 calculates a feature amount from a plurality of feature points for each pulse wave, and converts the feature amount into a blood pressure value using a regression line obtained in advance by a database.

  Next, the display unit 40 outputs the blood pressure indicated by the signal input from the processing device 30 (S4).

  As described above, in the present embodiment, the living body is irradiated with the light of the second wavelength from the detection signal of the reflected light or transmitted light from the blood vessel obtained by irradiating the living body with the light of the first wavelength. A pulse wave of a living body is obtained based on a subtraction value obtained by subtracting a detection signal of reflected light or transmitted light near the dermis which is large as noise. Therefore, a detection signal with less noise can be obtained, and the pulse wave of the living body, and thus the blood pressure of the living body, can be accurately measured.

<Second embodiment>
In this embodiment, a different form of the sensor unit will be described. FIG. 10 is a diagram schematically illustrating the sensor unit of the present embodiment. Note that the same elements as those of the biological information acquiring apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant description will be omitted.

  As shown in FIG. 10, the sensor unit 50 of the present embodiment includes a light source unit 51 in which a first light source 111, a second light source 121, and a third light source 122 are arranged on a substantially straight line. They are arranged radially around the light receiver 112. The light sources 111, 121, and 122 of each light source unit 51 are respectively arranged on different substantially concentric circles.

  That is, the first light source 111 of each light source unit 51 is arranged on a first circle centered on the light receiver 112. The second light source 121 of each light source unit 51 is arranged on a second circle centered on the light receiver 112 and having a smaller diameter than the first circle. The third light source 122 of each light source unit 51 is arranged on a third circle centered on the light receiver 112 and smaller than the second circle.

  The pulse wave to be measured has a different waveform depending on how the biological information acquisition device is attached to the living body (for example, whether it is in contact with or away from the living body and how much the pressure is). Therefore, among the light source units 51, the processing device 30 selects the light source unit 51 that satisfies a predetermined condition (for example, the light sources 111, 121, and 122 come into contact with the living body at a predetermined pressure), and selects the selected light source unit 51. When the pulse wave of the living body is obtained based on the detection signal obtained by irradiating the living body with the detection light from each of the light sources 111, 121, and 122, the pulse wave can be accurately measured.

  Note that the sensor unit 50 of the present embodiment subtracts a detection signal obtained by irradiating a living body with green light as detection light from a detection signal obtained by irradiating a living body with red light or infrared light as detection light. Although the configuration is based on the premise that the processing is performed, if the noise is not removed using the detection signal obtained by irradiating the living body with green light as the detection light, all the light sources mounted on the sensor unit 50 are the first light source. Of light sources 111. At this time, the interval between the radially adjacent first light sources and the interval between the circumferentially adjacent first light sources are appropriately set based on the wavelength of the emitted light.

  In this case, the detection signal obtained by irradiating the living body with the detection light from all the first light sources 111 is sampled, and the best signal state obtained by irradiating the living body with the detection light from the first light source 111 ( For example, a pulse wave of a living body is obtained based on a detection signal from which feature points are easily extracted. Thereby, the pulse wave of the living body can be accurately measured. That is, among the plurality of first light sources 111 arranged on a straight line, the detection signal having the best signal state and the best signal state among the plurality of first light sources 111 arranged on the same circle are determined. A first light source 111 that can be obtained is selected, and a pulse wave of the living body is obtained based on a detection signal obtained by irradiating the living body with detection light from the first light source 111.

  Also, when the data is collected by classifying by gender, age, weight, and the like, and collecting the data while keeping the distance between the first light source 111 and the light receiver 112 constant, the first database is created as described above. When the light sources 111 are arranged on substantially concentric circles, the distance between the first light source 111 and the light receiver 112 arranged on the same substantially circle is substantially equal, so that errors in the blood pressure estimation algorithm based on the database can be suppressed.

  Moreover, compared to the case where the first light sources 111 are arranged in a matrix on the substrate 13, the number of the first light sources 111 can be reduced by disposing the first light sources 111 on substantially concentric circles as described above. As a result, it is possible to contribute to weight reduction of the biological information acquisition device.

  Incidentally, Patent Document 2 (Japanese Patent No. 2766317) discloses a configuration in which light-emitting elements are arranged on a circle centered on a light-receiving element, but relates to a technique for measuring oxygen saturation in blood.

<Third embodiment>
Different modes of the sensor unit in the case where noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light will be described. FIG. 11 is a diagram schematically illustrating the sensor unit of the present embodiment. Note that the same elements as those of the biological information acquiring apparatus 1 according to the first embodiment will be described using the same reference numerals, and redundant description will be omitted.

  As shown in FIG. 11, the sensor unit 60 of the present embodiment is configured such that a plurality of light receivers 112 are arranged on a substantially straight line so that a light receiver unit 61 is formed on a substrate 13 in a radial manner with a first light source 111 as a center. Are located. The light receivers 112 of each light receiver unit 61 are arranged on different substantially concentric circles. At this time, the interval between the light receivers 112 adjacent in the radial direction and the interval between the light receivers 112 adjacent in the circumferential direction are appropriately set based on the wavelength of the light emitted from the first light source 111.

  As described above, since the pulse wave to be measured has a different waveform depending on how the biological information acquisition device is attached to the living body, a predetermined condition is satisfied among the light receivers 112 (for example, a contact with the living body at a predetermined pressure is made). ) By selecting the light receiver 112 and obtaining the pulse wave of the living body based on the detection signal of the selected light receiver 112, the measurement accuracy of the pulse wave can be improved.

  Also, when the data is collected by classifying by gender, age, weight, and the like, and the distance between the first light source 111 and the light receiver 112 is kept constant to create the above-described database, the light receiver 112 is used as described above. Are arranged on substantially concentric circles, the distance between the light receivers 112 on the substantially same circles to the first light source 111 is substantially constant, so that errors in the blood pressure estimation algorithm based on the database can be suppressed.

  Moreover, compared to the case where the light receivers 112 are arranged in a matrix on the substrate 13, the number of the light receivers 112 can be reduced by arranging the light receivers 112 on substantially concentric circles as described above. This can contribute to weight reduction of the biological information acquisition device.

<Fourth embodiment>
Different modes of the sensor unit in the case where noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light will be described. FIG. 12 is a diagram schematically illustrating the sensor unit of the present embodiment. Note that the same elements as those of the biological information acquiring apparatus 1 according to the first embodiment will be described using the same reference numerals, and redundant description will be omitted.

  As shown in FIG. 12, the sensor unit 70 of the present embodiment has a light receiver 112 on a substantially spiral line (indicated by a two-dot chain line in FIG. Are located. Also in this case, the measurement accuracy of the pulse wave is improved by selecting the light receiver 112 satisfying the predetermined condition from the plurality of light receivers 112 and obtaining the pulse wave of the living body based on the detection signal of the selected light receiver 112. Can be improved. At this time, the interval between the photodetectors 112 adjacent on the spiral is appropriately set based on the wavelength of the light emitted from the first light source 111 and the like.

  In the present embodiment, the light receiver 112 is arranged substantially on the spiral around the first light source 111. However, the first light source 111 is arranged substantially on the spiral around the light receiver 112, and a predetermined The first light source 111 that satisfies the condition may be selected, and a pulse wave of the living body may be obtained based on a detection signal of reflected light obtained by irradiating the living body with detection light from the selected first light source 111.

<Fifth Embodiment>
Different modes of the sensor unit in the case where noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light will be described. FIG. 13 is a diagram schematically illustrating the sensor unit of the present embodiment. Note that the same elements as those of the biological information acquiring apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant description will be omitted.

  In the sensor unit 80 of the present embodiment, as shown in FIG. 13, a plurality of first light sources 111 and light receivers 112 are arranged on a substrate 13 in a substantially straight line. Also in this case, by selecting a first light source 111 that satisfies a predetermined condition from among the plurality of first light sources 111 and obtaining a pulse wave of a living body based on a detection signal of the selected first light source 111, The measurement accuracy of the pulse wave can be improved.

  In the present embodiment, the plurality of first light sources 111 and the plurality of light receivers 112 are arranged on a substantially straight line. May be selected, and a pulse wave of the living body may be obtained based on a detection signal obtained by irradiating the living body with detection light from the selected light receiving unit 112.

<Sixth Embodiment>
Different modes of the sensor unit in the case where noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light will be described. FIG. 14 is a diagram schematically illustrating the sensor unit of the present embodiment. Note that the same elements as those of the biological information acquiring apparatus 1 according to the first embodiment will be described using the same reference numerals, and redundant description will be omitted.

  In the sensor unit 90 of the present embodiment, as shown in FIG. 14, a plurality of ring-shaped light sources 91 having different diameters are arranged on a substrate 13 with a light receiver 112 as a center. Also in this case, a light source 91 that satisfies a predetermined condition (for example, comes into contact with a living body at a predetermined pressure) is selected from the light sources 91 and a detection signal obtained by irradiating the living body with detection light from the selected light source 91. By obtaining the pulse wave of the living body based on the above, the measurement accuracy of the pulse wave can be improved. Here, the interval between the adjacent light sources 91 is appropriately set based on the wavelength of the emitted light and the like.

  In the present embodiment, the ring-shaped light source 91 is arranged around the light receiver 112, but a plurality of ring-shaped light receivers are arranged around the point light source, and a light receiver satisfying a predetermined condition is selected. Alternatively, the pulse wave of the living body may be measured based on the detection signal of the selected light receiver.

<Seventh embodiment>
The substrate 13 is preferably made of a flexible substrate. Thereby, the light source and the light receiving device can be brought into good contact with the living body by making the substrate 13 follow the curvature of, for example, the wrist of the living body.

  When the living body information acquisition device in which the substrate 13 is formed of a flexible substrate is attached to a living body, the substrate 13 is curved and the above-described concentric circle is deformed. Therefore, with the biological information acquisition device attached to the living body, one of the light source and the light receiver is centered on the other while the substrate 13 is flattened so that the light source or the light receiver is arranged substantially concentrically. It is preferable to arrange on a concentric ellipse. Thereby, when creating the database, the distance between the first light source 111 and the light receiver 112 can be accurately and constantly fixed.

<Eighth Embodiment>
When detecting the contact pressure of the light source and the light receiver on the living body as described above, the following configuration may be adopted. FIG. 15 is a diagram schematically illustrating a sensor unit configured to detect a contact pressure of the first light source with the living body.

  As shown in FIG. 15, the sensor unit of the present embodiment includes a pressure detector 14 between the first light source 111 and the substrate 13. As the pressure detector 14, a general pressure sensor can be used.

  When such a configuration is adopted in, for example, a sensor unit including a plurality of first light sources 111, the processing device sets a predetermined one of the plurality of first light sources 111 based on a detection signal of the pressure detection unit 14. A first light source 111 having a pressure value or more is selected, and a pulse wave of the living body is obtained based on a detection signal obtained by irradiating the living body with detection light from the selected first light source 111. Thus, it is possible to avoid the difficulty of measurement due to the variation in the mounting state of the biological information acquisition device on the living body and the individual difference of the living body.

  However, in FIG. 15, the configuration is such that the contact pressure of the first light source 111 to the living body can be detected. For example, in the case of a sensor unit including a plurality of 13 may be arranged between the pressure detecting section 14 and the pressure detecting section 13.

<Ninth embodiment>
Here, it is preferable that the configuration is such that the contact pressure of the light source and the light receiver to the living body can be adjusted to a preset value. FIG. 16 is a diagram schematically illustrating a configuration in which the contact pressure of the first light source with the living body can be adjusted to a preset value.

  In the present embodiment, as shown in FIG. 16, a pressure detecting unit 14 and a pressure adjusting unit 15 are provided between the first light source 111 and the substrate 13. As the pressure adjusting unit 15, for example, an actuator can be used.

  When such a configuration is adopted, for example, in a sensor unit including a plurality of first light sources 111, the processing device controls the pressure adjustment unit 15 based on a detection signal from the pressure detection unit 14, and controls the first light source 111. Is adjusted to a preset value. Then, the processing device irradiates the living body with the detection light from the plurality of first light sources 111 and obtains the pulse wave of the living body based on the detection signal having the best signal state (for example, the feature point is easily extracted). obtain. Thus, it is possible to avoid the difficulty of measurement due to the variation in the mounting state of the biological information acquisition device on the living body and the individual difference of the living body.

  However, in FIG. 16, the configuration is such that the contact pressure of the first light source 111 to the living body can be adjusted. For example, in the case of a sensor unit including a plurality of light receivers 112, each light receiver 112 and the substrate 13 The pressure detecting unit 14 and the pressure adjusting unit 15 may be arranged between the two.

<Tenth embodiment>
When a sensor unit including a plurality of first light sources 111 or a plurality of light receivers 112 is used, a plurality of other first light sources 111 having different distances from one of the central first light source 111 and the light receiver 112 are used. Alternatively, the blood pressure of the living body may be derived by a general PWTT (Pulse Wave Transit Time) method based on the pulse waves obtained at different positions of the living body by operating the light receiver 112.

<Eleventh embodiment>
When the sensor unit includes a plurality of first light sources 111, it is preferable to change the frequency of light emitted from the first light source according to the distance from the light receiver 112. For example, the frequency of the light emitted from the first light source 111 is increased as the distance from the light receiver 112 increases. This makes it possible to adjust the depth of the light emitted from the first light source 111 into the living body.

  The embodiments of the biological information acquiring apparatus and the biological information acquiring method according to the present invention have been described above. However, the present invention is not limited to the above, and can be changed without departing from the technical idea of the present invention.

  For example, in the above embodiment, the detection light measures the pulse wave of the living body based on the reflected light reflected in the living body, but the detection light detects the pulse wave of the living body based on the transmitted light transmitted through the living body. May be measured. In this case, the light source and the light receiver may be arranged such that the living body is arranged between the light source and the light receiver.

  For example, in the second and subsequent embodiments, a sensor unit including a plurality of first light sources 111 or light receivers 112 has been described, but the present invention is not limited to the above-described configuration. That is, the plurality of first light sources 111 or the light receivers 112 may be irregularly or regularly arranged on the substrate 13.

  For example, the biological information acquisition device of the above embodiment can be incorporated in a wearable terminal such as a wristwatch terminal. That is, it can be considered as a wristwatch terminal including the biological information acquisition device. Furthermore, the sensor unit 10 is provided in the wristwatch terminal and has a wireless communication unit, and other configurations (for example, the processing device 30 and the display unit 40) may be provided in the smartphone. In this case, the analog data or digital data obtained by the watch terminal is transferred to the smartphone by wireless communication. Then, the smartphone that has received the data may perform part or all of the processing for measuring the blood pressure.

DESCRIPTION OF SYMBOLS 1 Biological information acquisition device 10 Sensor unit 11 1st detection part, 111 1st light source, 112 light receiver 12 2nd detection part, 121 2nd light source, 122 3rd light source 13 Substrate 14 Pressure detection part 15 Pressure Adjustment unit 20 AFE, 21 amplifier, 22 noise removal filter, 23 ADC
Reference Signs List 30 processing device, 31 filter, 32 memory, 33 digital filter, 34 power management unit 40 display unit 50 sensor unit, 51 light source unit 60 sensor unit, 61 light receiver unit 70 sensor unit 80 sensor unit 90 sensor unit 90 sensor unit, 91 light source

Claims (5)

Board and
A light receiver provided on the substrate,
Provided on the substrate, a plurality of first light source that is placed on a first circle centered on the front Ki受 light unit,
A plurality of second light sources provided on the substrate and arranged on a second circle different from the first circle centered on the light receiver;
From the first detection signal of the reflected light or transmitted light obtained by irradiating light having a wavelength in the green body the light receiver has received, the living body second irradiating the obtained reflected light or transmitted light of wavelength A processing unit that derives a pulse wave of the living body based on a subtraction value obtained by subtracting a light detection signal ,
Equipped with a,
The first light source irradiates the living body with light of a first wavelength,
The second light source irradiates the living body with light having a second wavelength of 495 nm or more and 570 nm or less,
The irradiation of the living body with the light of the first wavelength and the irradiation of the living body with the light of the second wavelength are set in advance to be substantially equal to the period of the pulse wave of the living body so that the irradiation periods do not overlap. A biological information acquisition apparatus that performs the same period for a substantially equal period . The biological information acquisition device according to claim 1, wherein the first light source and the second light source are arranged on a substantially straight line . Wherein the substrate is a flexible substrate, the biological information acquisition apparatus according to claim 1 or 2. In a state in which the biological information acquisition apparatus has curved the flexible substrate is mounted on the living body, is arranged in front Symbol first light source before SL on the first circle, the second light source is the second as arranged in circle, while flattened the flexible substrate is disposed in front Symbol first ellipse on which the first light source is centered on the light receiver, said second light source The biological information acquiring device according to claim 3 , wherein the biological information acquiring device is arranged on a second ellipse different from the first ellipse around the light receiver . Watch terminal having a biological information acquisition apparatus according to any one of claims 1 to 4.