JP2019010380A - Pulse wave measurement apparatus - Google Patents

Abstract

To measure a pulse wave with a proper amplitude.SOLUTION: A pulse wave measurement apparatus comprises: a piezoelectric sensor 1 arranged to face a pulse wave measurement portion; and a cuff band 7 being a pressing part. The cuff band 7 is positioned on a downstream side of a radial artery 8a to the piezoelectric sensor 1. When pressing by the cuff band 7 is performed to a left wrist 8 of a subject, the radial artery 8a on an upstream side of the pressed portion is expanded, then a pulse wave from the expanded radial artery 8a is transmitted to the piezoelectric sensor 1. Amplitude of the pulse wave is larger than that of a pulse wave transmitted from a radial artery which is not being expanded.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for measuring a pulse wave of a living body.

  Various devices for measuring a pulse wave of a living body such as a human body are provided. Since the pulse wave contains a lot of information indicating the state of the living body, it is desired to accurately measure the waveform. Under the prior art, as shown in Patent Document 1, for example, a piezoelectric sensor is pressed against the skin surface of a person to be measured by a cuff band, and a pulse wave transmitted from an artery below the skin surface to the piezoelectric sensor is detected. I was measuring.

JP 2004-313409 A

  By the way, the above-described conventional technology presses the piezoelectric sensor from the skin surface of the person to be measured toward the artery side, so that the artery in the region where the piezoelectric sensor is arranged may be compressed to reduce the amplitude of the pulse wave. There was a problem.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a technical means that makes it possible to measure a pulse wave having an appropriate amplitude.

  The present invention provides a pulse wave measuring device including a piezoelectric sensor and a pressing portion arranged to face a pulse wave measuring portion.

  According to this invention, the piezoelectric sensor measures the pulse wave at the position adjacent to the position pressed by the pressing portion on the skin surface of the measurement subject. Therefore, it is possible to measure a pulse wave having an appropriate amplitude from the artery in the region without compressing the artery in the region facing the piezoelectric sensor.

  In a preferred aspect, the pressing portion is disposed on the downstream side of the artery with respect to the piezoelectric sensor.

  According to this aspect, when the artery is pressed by the pressing portion, the artery on the upstream side of the pressed portion expands, and a pulse wave having a large amplitude is transmitted from the expanded artery to the piezoelectric sensor.

It is a figure which shows the structure of the pulse-wave measuring apparatus which is 1st Embodiment of this invention. It is sectional drawing which shows the structural example of the piezoelectric sensor in the same embodiment. It is a figure which shows the operation | movement of the embodiment. It is a figure which illustrates the pulse waveform measured in the embodiment. It is a figure which shows the structure of the pulse-wave measuring apparatus which is 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the wristband in the same embodiment. It is a figure which shows the structure of the pulse-wave measuring apparatus which is 3rd Embodiment of this invention. It is a figure which shows the structure of the pulse-wave measuring apparatus which is 4th Embodiment of this invention. It is a figure which shows the structure of the pulse-wave measuring apparatus which is 5th Embodiment of this invention. It is a figure which shows the structure of the pulse-wave measuring apparatus which is 6th Embodiment of this invention. It is a figure which shows the structure of the pulse-wave measuring apparatus which is 7th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram showing a configuration of a pulse wave measuring apparatus 100A according to the first embodiment of the present invention.
In this pulse wave measuring device 100A, the piezoelectric sensor 1 is a sheet-like sensor, and is attached to the skin surface area on the radial artery 8a of the left wrist 8 of the measurement subject. The piezoelectric sensor 1 converts a pulse wave (pressure wave) transmitted from the radial artery 8a into a voltage.

  The piezoelectric sensor 1 is connected to an amplifier 3 via an impedance conversion device 2. The impedance conversion device 2 is a device that performs impedance conversion for eliminating mismatch between the output impedance of the piezoelectric sensor 1 and the input impedance of the amplifier 3. The amplifier 3 amplifies the output voltage of the piezoelectric sensor 1 supplied via the impedance conversion device 2 and supplies the amplified output voltage to the oscilloscope 4 and the pressure setting device 5.

  The oscilloscope 4 is a device that displays the output voltage waveform of the amplifier 3. The output voltage waveform of the amplifier 3 shows a pulse waveform measured by the piezoelectric sensor 1.

  The pressure setting device 5 is connected to a pressurizing device 6, and the pressurizing device 6 is connected to the cuff band 7 through a hollow tube 7 a.

  In the present embodiment, the piezoelectric sensor 1 and the cuff band 7 as a pressing portion are arranged facing the pulse wave measurement site. More specifically, the cuff band 7 in the present embodiment is wound around a position on the left wrist 8 of the measurement subject at a position downstream of the radial artery 8a from the piezoelectric sensor 1 and applies pressure to the position. It is. The cuff band 7 is a hollow band made of an elastic body such as rubber. The hollow region of the cuff band 7 is connected to the inside of the hollow tube 7a.

  The pressurizing device 6 and the pressure setting device 5 are pressure adjusting means for adjusting the pressure of the cuff band 7 that is a pressing portion. The pressurizing device 6 supplies air into the cuff belt 7 through the tube 7a, and increases the air pressure in the cuff belt 7, and takes out the air from the cuff belt 7 through the tube 7a. A pressure reducing function for reducing the air pressure in the belt 7 is provided. Further, the pressurizing device 6 measures the air pressure in the cuff belt 7, and when the air pressure is lower than the pressure set value given from the pressure setting device 5, the air pressure in the cuff belt 7 is increased by the pressurizing function. When the air pressure is higher than the pressure set value, the pressure control function is provided to reduce the air pressure in the cuff belt 7 by the pressure reducing function.

  The pressure setting device 5 is a device that gives a pressure setting value to the pressurizing device 6. There are a manual mode and an automatic mode as operation modes for determining a pressure set value to be applied to the pressurizing device 6. In the manual mode, the pressure setting device 5 increases or decreases the pressure setting value in accordance with an operation of an operation element (for example, an increase instruction button and a decrease instruction button) provided in the pressure setting device 5. In the automatic mode, the pressure setting device 5 controls the pressure setting value based on the output voltage waveform of the amplifier 3.

  For controlling the pressure setting value, various modes are conceivable. For example, the pressure setting device 5 analyzes the pulse waveform indicated by the output voltage of the amplifier 3 while changing the pressure setting value, so that one pulse worth is controlled. A range of the pressure setting value in which the distortion between the beats of the pulse waveform falls within a predetermined limit is obtained, and for example, the center value of the range is set as the pressure setting value.

FIG. 2 is a cross-sectional view showing a configuration example of the piezoelectric sensor 1 in the present embodiment. This piezoelectric sensor 1 has a configuration in which electrodes 11 and 12 are attached to both surfaces of a thin plate-like piezoelectric body 10.
The piezoelectric body 10 is formed of a piezoelectric material that converts pressure into voltage, receives stress from a pulse wave from the subject, and generates a potential difference according to the acceleration of the stress change.

  The piezoelectric material forming the piezoelectric body 10 may be, for example, an inorganic material such as lead zirconate titanate, but is preferably a polymer piezoelectric material having flexibility so as to be in close contact with the surface of a living body. .

  Examples of the polymer piezoelectric material include polyvinylidene fluoride (PVDF), vinylidene fluoride-trifluoride ethylene copolymer (P (VDF / TrFE)), and vinylidene cyanide-vinyl acetate copolymer (P (VDCN / VAc)) and the like.

  In addition, as the piezoelectric body 10, a large number of flat pores are formed in, for example, polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET) or the like that does not have piezoelectric characteristics, for example, corona discharge It is also possible to use a material which has piezoelectric properties by polarizing and charging the opposed surfaces of the flat pores.

  As a minimum of average thickness of piezoelectric material 10, 10 micrometers is preferred and 50 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the piezoelectric body 10 is preferably 500 μm, and more preferably 200 μm. When the average thickness of the piezoelectric body 10 is less than the lower limit, the strength of the piezoelectric body 10 may be insufficient. On the contrary, when the average thickness of the piezoelectric body 10 exceeds the upper limit, the deformability of the piezoelectric body 10 is reduced, and the detection sensitivity may be insufficient.

  The electrodes 11 and 12 are laminated on both surfaces of the piezoelectric body 10 and are used for detecting a potential difference between the front and back of the piezoelectric body 10. Wiring for connecting to the impedance converter 2 is connected to the electrodes 11 and 12.

  The material of the electrodes 11 and 12 may be any material as long as it has conductivity. Examples thereof include metals such as aluminum, copper and nickel, and carbon.

  The average thickness of the electrodes 11 and 12 is not particularly limited, and may be, for example, 0.1 μm or more and 30 μm or less, depending on the lamination method. When the average thickness of the electrodes 11 and 12 is less than the lower limit, the strength of the electrodes 11 and 12 may be insufficient. On the other hand, when the average thickness of the electrodes 11 and 12 exceeds the upper limit, there is a possibility that the transmission of vibration to the piezoelectric body 10 may be hindered.

  The method for laminating the electrodes 11 and 12 on the piezoelectric body 10 is not particularly limited, and examples thereof include metal deposition, carbon conductive ink printing, and silver paste coating and drying.

  Next, the operation of this embodiment will be described. The measurer wraps the cuff strip 7 around the left wrist 8 of the subject as shown in FIG. Further, the measurer applies gel to the surface of the electrode 11 of the piezoelectric sensor 1, and attaches the piezoelectric sensor 1 to the skin surface region on the upstream side of the radial artery 8 a with respect to the cuff band 7. Then, an instruction to start measurement is given to the pressure setting device 5. As a result, the pressure setting device 5 starts an operation of controlling the pressure setting value for the pressurizing device 6 based on the output voltage waveform of the amplifier 3 (that is, the pulse waveform of the radial artery).

  FIG. 3 shows the radial artery 8a, the cuff band 7 and the piezoelectric sensor 1 in the left wrist 8 of the measurement subject in this state. As shown in FIG. 3, the piezoelectric sensor 1 is affixed to the skin surface of the left wrist 8 of the person to be measured by the gel 13 and faces the radial artery 8a. Blood flows in the radial artery 8a in the direction from the left side to the right side in FIG. The radial artery 8a repeatedly expands and contracts due to the pulsation that sends out the blood flow, and vibration in the thickness direction of the piezoelectric sensor 1 is generated on the skin surface of the left wrist 8 to which the piezoelectric sensor 1 is attached. Then, the pressure in the thickness direction of the piezoelectric sensor 1 is changed by the driving force from the surface of the left wrist 8, and a voltage corresponding to this pressure is output from the piezoelectric sensor 1. In this way, a voltage waveform reflecting a pulse wave (pressure wave) from the radial artery 8 a is output from the piezoelectric sensor 1 and supplied to the oscilloscope 4 and the pressure setting device 5 via the impedance conversion device 2 and the amplifier 3.

  As shown in FIG. 3, the cuff band 7 faces a section downstream of the piezoelectric sensor 1 in the radial artery 8a. When the cuff band 7 is pressurized by the pressurizing device 6, the cuff band 7 compresses the radial artery 8a in the downstream section and blocks the blood flow in the section. As a result, in the radial artery 8a, the blood vessel in the section facing the piezoelectric sensor 1 on the upstream side of the cuff zone 7 expands, and the amplitude of the pulse wave generated in the section increases. As a result, the amplitude of the voltage waveform (pulse waveform) measured by the piezoelectric sensor 1 and supplied to the oscilloscope 4 and the pressure setting device 5 increases.

  Here, the pulse waveform measured by the piezoelectric sensor 1 depends on the pressure of the cuff band 7. 4A to 4C illustrate pulse waveforms that change depending on the pressure of the cuff band 7. In these figures, the horizontal axis represents time, and the vertical axis represents pressure.

  When the pressure in the cuff band 7 is increased, the pulse waveform changes accordingly as shown in FIG. 4 (a) → FIG. 4 (b) → FIG. 4 (c). In FIG. 4A, since the pressure in the cuff zone 7 is insufficient, the amplitude of the measured pulse waveform is small and the waveform is also unstable. In FIG. 4C, the pressure in the cuff zone 7 is excessive and the amplitude of the pulse waveform is large, but the distortion of the pulse waveform is large. In each of the states shown in FIGS. 4A and 4C, there is a problem in obtaining accurate biological information by analyzing the pulse waveform. In FIG. 4B, the pressure of the cuff band 7 is an appropriate value, the amplitude is sufficient, the distortion is small, and a stable pulse waveform is obtained. Thus, in order to measure a pulse waveform from which accurate biological information can be obtained, it is necessary to control the pressure of the cuff zone 7 to an appropriate value.

  Therefore, in the present embodiment, the pressure setting device 5 is provided with two functions for controlling the pressure set value. One is the manual mode function described above. In this manual mode, the measurer performs an increase / decrease operation of the pressure setting value output from the pressure setting device 5 so that an appropriate pulse wave voltage waveform is displayed on the oscilloscope 4. The other is the function of the automatic mode described above. In this automatic mode, the pressure setting device 5 analyzes the pulse wave voltage waveform while changing the pressure setting value, so that the pressure setting value at which the beat distortion of the pulse wave voltage waveform for one beat falls within a predetermined limit. And the center value of the range is set as the pressure setting value. By adjusting the pressure set value in the manual mode or the automatic mode, accurate pulse wave measurement can be performed.

  As described above, according to the present embodiment, since the piezoelectric sensor 1 arranged facing the pulse wave measurement site and the cuff band 7 serving as the pressing portion are included, the artery in the region facing the piezoelectric sensor 1 is compressed. Without this, the piezoelectric sensor 1 can measure a pulse wave having an appropriate amplitude from the artery in the region. Further, according to the present embodiment, when the pulse wave of the radial artery is measured by the piezoelectric sensor 1, the location downstream of the radial artery from the measurement location is pressurized by the cuff band 7, so the radial artery at the measurement location And the amplitude of the measured pulse waveform can be increased. Therefore, the pulse waveform can be accurately measured.

Second Embodiment
FIG. 5 is a diagram showing a configuration of a pulse wave measuring apparatus 100B according to the second embodiment of the present invention. The pulse wave measuring device 100B according to the present embodiment includes the impedance conversion device 2, the amplifier 3, and the oscilloscope 4 in the first embodiment in addition to the piezoelectric sensor 1 and the wristband 7B shown in FIG. However, illustration of these devices is omitted.

  The piezoelectric sensor 1 has the same configuration as the piezoelectric sensor 1 of the first embodiment. This piezoelectric sensor 1 is affixed to the skin surface area on the radial artery 8a of the left wrist 8 of the person to be measured with a gel.

  The wristband 7B is attached to the skin surface region on the downstream side of the radial artery 8a with respect to the piezoelectric sensor 1 in the left wrist 8 of the measurement subject. The wristband 7B is made of an elastic body such as rubber.

  FIG. 6 is a cross-sectional view showing a configuration example of the wristband 7B. In the wristband 7B, a convex portion 71 protruding on an arc is provided in a region of the inner peripheral surface facing the radial artery. The convex portion 71 locally compresses the skin surface region on the radial artery 8a in a state where the wristband 7B is worn on the left wrist 8 of the measurement subject. The wrist band 7B has an elastic coefficient, shape, width, thickness, and the like determined so that the convex portion 71 on the inner peripheral surface applies a pressure suitable for pulse wave measurement to the skin surface area of the measurement subject. ing. In the present embodiment, the piezoelectric sensor 1 and the convex portion 71 on the inner side of the wristband 7B are the piezoelectric sensor and the pressing portion arranged to face the pulse wave measurement site.

  According to the present embodiment, pressure is locally applied to a region on the radial artery 8a on the surface of the left wrist 8 of the measurement subject during pulse wave measurement. For this reason, in the radial artery 8a, the upstream region of the portion to which pressure is applied by the convex portion 71 can be expanded more effectively than in the first embodiment, and the amplitude of the measured pulse waveform can be increased. In addition, according to the present embodiment, the pressure setting device 5, the pressurizing device 6, and the cuff band 7 in the first embodiment are not necessary, so that a small-scale and low-cost pulse wave measuring device can be realized. .

<Third Embodiment>
FIG. 7 is a diagram showing a configuration of a pulse wave measuring apparatus 100C according to the second embodiment of the present invention. The pulse wave measurement device 100C according to the present embodiment includes piezoelectric sensors 1C1 and 1C2 and wristbands 7C1 and 7C2.

  The piezoelectric sensors 1C1 and 1C2 are sensors having the same configuration as the piezoelectric sensor 1 of the first embodiment. In the present embodiment, as shown in FIG. 7, a piezoelectric sensor 1C1 is attached to a position near the left palm on the radial artery 8a on the surface of the left wrist 8 of the person to be measured, and the radial artery 8a is positioned more than this position. Then, the piezoelectric sensor 1C2 is attached to a position upstream by a predetermined distance.

  The wristbands 7C1 and 7C2 are wristbands having the same configuration as the wristband 7B of the second embodiment. The wristband 7C1 is attached to a region of the measurement subject's left wrist 8 on the downstream side of the radial artery 8a with respect to the piezoelectric sensor 1C1, and a convex portion (not shown) provided on the inner peripheral surface thereof is on the radial artery 8a. Compress the skin surface area locally. The wristband 7C2 is attached to the skin surface region on the left wrist 8 of the measurement subject on the downstream side of the radial artery 8a with respect to the piezoelectric sensor 1C2 and on the upstream side of the piezoelectric sensor 1C1, and on the inner peripheral surface thereof. The provided convex portion (not shown) locally compresses the skin surface area on the radial artery 8a.

  The piezoelectric sensor 1C1 is connected to the pulse wave observation device via the one corresponding to the impedance conversion device 2 and the amplifier 3 of the first embodiment, and the piezoelectric sensor 1C2 is the impedance conversion device 2 and the amplifier of the first embodiment. Although the same pulse wave observation device is connected through the one corresponding to 3, the illustration thereof is omitted.

  The pulse wave observation device is an oscilloscope capable of displaying a 2-channel pulse waveform obtained by the piezoelectric sensors 1C1 and 1C2, for example. In a preferred embodiment, the pulse wave observation device has a function of measuring the relative delay time of the pulse waveforms of the two channels.

  Also in this embodiment, the same effect as the second embodiment can be obtained. In addition, according to the present embodiment, since the relative delay time of the two-channel pulse waveforms obtained by the piezoelectric sensors 1C1 and 1C2 can be measured, the pulse wave is changed from the position of the piezoelectric sensor 1C2 to the position of the piezoelectric sensor 1C1. It is possible to determine the propagation speed of propagation through the radial artery 8a.

<Fourth embodiment>
FIG. 8 is a cross-sectional view showing a configuration of a pulse wave measuring device 100D according to the fourth embodiment of the present invention. The pulse wave measuring device 100D according to the present embodiment includes the devices of the impedance conversion device 2, the amplifier 3, and the oscilloscope 4 in the first embodiment, in addition to the piezoelectric sensor 1, the fabric 21, and the pressing portion 31 shown in FIG. In FIG. 8, the illustration of these devices is omitted. In the present embodiment, the piezoelectric sensor 1 and the pressing portion 31 are a piezoelectric sensor and a pressing portion that are arranged facing the pulse wave measurement site.

  More specifically, in this embodiment, the piezoelectric sensor 1 and the pressing portion 31 are fixed side by side on one surface 21a of the fabric 21. The piezoelectric sensor 1 has the same configuration as the piezoelectric sensor 1 of the first embodiment. The pressing portion 31 is a plate-like member that is thicker than the piezoelectric sensor 1.

  When measuring the pulse wave, the piezoelectric sensor 1 is opposed to a desired position on the radial artery of the measurement subject, and the pressing portion 31 is opposed to a position on the radial artery downstream of the position. The surface 21a is affixed to the skin surface of the wrist of the measurement subject by gel or the like. At that time, the pressing portion 31 is pressed against the radial artery of the measurement subject with an appropriate pressing force by the tension generated in the fabric 21, and the radial artery at a position upstream of the pressing portion expands. A pulse wave is transmitted to the piezoelectric sensor 1 from the expanded radial artery. The amplitude of this pulse wave is larger than the amplitude of the pulse wave transmitted from the radial artery that is not inflated. Therefore, in this embodiment, the same effect as the second embodiment can be obtained.

<Fifth Embodiment>
FIG. 9 is a sectional view showing the configuration of a pulse wave measuring apparatus 100E according to the fifth embodiment of the present invention. The pulse wave measuring device 100E according to the present embodiment includes each device of the impedance conversion device 2, the amplifier 3, and the oscilloscope 4 in the first embodiment in addition to the piezoelectric sensor 1 and the pressing unit 31 shown in FIG. However, illustration of these devices is omitted.

  In the present embodiment, the piezoelectric sensor 1 is basically a sheet-like sensor having the same configuration as the piezoelectric sensor 1 of the first embodiment, but having a larger area than that of the first embodiment. The pressing portion 31 is a plate-like member and is fixed to a partial region of one surface of the piezoelectric sensor 1.

  At the time of pulse wave measurement, the surface opposite to the surface on which the pressing portion 31 is fixed in the piezoelectric sensor 1 is pressed against the skin surface area on the radial artery of the left wrist of the measurement subject. At that time, the orientation of the piezoelectric sensor 1 is adjusted so that the left side in FIG. 9 is the downstream side of the radial artery and the right side in FIG. 9 is the upstream side of the radial artery. Further, the pressing portion 31 is pressed toward the piezoelectric sensor 1 by some pressing means. The pressing means may be a measurer's finger or a cuff band or the like.

  When the pressing portion 31 is pressed, this pressing force is transmitted to the radial artery via the piezoelectric sensor 1. Here, the pressing force transmitted to a region outside this region is smaller than that of the region directly below the pressing portion 31 in the radial artery. For this reason, the radial artery in the region upstream of the region immediately below the pressing portion 31 in the radial artery expands. The pulse wave from the expanded radial artery is transmitted to a region upstream of the radial artery relative to the region where the pressing portion 31 is not fixed in the piezoelectric sensor 1. The amplitude of this pulse wave is larger than the amplitude of the pulse wave transmitted from the radial artery that is not inflated. Therefore, in this embodiment, the same effect as the second embodiment can be obtained.

<Sixth Embodiment>
FIG. 10 is a sectional view showing the configuration of a pulse wave measuring apparatus 100F according to the sixth embodiment of the present invention. In the fifth embodiment, the pressing portion 31 is fixed to a partial region of one surface of the piezoelectric sensor 1. On the other hand, in this embodiment, the pressing part 31 is being fixed to the position on the edge surrounding one surface of the piezoelectric sensor 1 in the state inclined with respect to the said surface. About another point, it is the same as that of the said 5th Embodiment.

  In the present embodiment, when the pressing portion 31 is pressed, the pressing force is locally transmitted to a narrow region immediately below the edge of the piezoelectric sensor 1 in the radial artery of the measurement subject. In the radial artery, a region upstream of the transmission region of the pressing force is expanded. Then, the pulse wave from the expanded radial artery is transmitted to the piezoelectric sensor 1. The amplitude of this pulse wave is larger than the amplitude of the pulse wave transmitted from the radial artery that is not inflated. Therefore, in this embodiment, the same effect as the second embodiment can be obtained.

<Seventh embodiment>
FIG. 11 is a diagram showing a configuration of a pulse wave measurement device 100G according to the seventh embodiment of the present invention. FIG. 11 shows the pressing portion 32 and the piezoelectric sensor 1 arranged on the inner peripheral surface of the wristband 22 attached to the left wrist of the measurement subject. A pulse wave measuring device 100G according to the present embodiment includes an impedance conversion device 2, an amplifier 3, an oscilloscope 4, and a pressure setting device 5 in the first embodiment, in addition to the piezoelectric sensor 1, the pressing unit 31, and the wristband 22 shown in FIG. The pressurizing device 6 and the pressurizing device 6 are included, but these devices are not shown in FIG.

  The piezoelectric sensor 1 has the same configuration as the piezoelectric sensor 1 of the first embodiment, and is connected to the impedance conversion device 2 (see FIG. 1). The pressing part 32 is a hollow annular air bag fixed to the inner peripheral surface of the wristband 22, and is connected to the pressurizing device 6 shown in FIG. Similar to the first embodiment, the pressure device 6 increases or decreases the pressure of air applied to the hollow region of the pressing portion 32.

  At the time of measuring the pulse wave, the wristband 22 is attached to the left wrist of the measurement subject so that the pressing portion 32 is located on the downstream side of the radial artery and the piezoelectric sensor 1 is located on the upstream side of the radial artery. In this state, as in the first embodiment, the pressing force applied from the pressing portion 32 is adjusted to a position on the downstream side of the radial artery, and the pulse wave is measured by the piezoelectric sensor 1 on the upstream side of the radial artery. Therefore, also in this embodiment, the same effect as the first embodiment is obtained.

<Other embodiments>
As mentioned above, although each embodiment of this invention was described, other embodiment can be considered to this invention. For example:

(1) In each of the above embodiments, the present invention is applied to an apparatus for measuring a radial artery wave. However, the present invention is also applicable to an apparatus for measuring a pulse wave other than a radial artery wave.
(2) The fabric 21 in the fourth embodiment may be replaced with a wristband.
(3) In the fourth embodiment, the fabric 21 may be replaced with an elastic adhesive tape, and the pressing portion 31 may be pressed against the skin surface of the person to be measured with an appropriate pressing force by the elastic force of the adhesive tape.
(4) In the seventh embodiment, the piezoelectric sensor 1 and the pressing portion 32 that is a hollow annular air bag are provided on the inner peripheral surface of the wristband 22. However, the piezoelectric sensor 1 and the hollow rod-shaped air are provided on the fabric. A bag may be provided.

100A to 100G: Pulse wave measuring device, 1, 1C1, 1C2 ... Piezoelectric sensor, 2 ... Impedance converter, 3 ... Amplifier, 4 ... Oscilloscope, 5 ... Pressure setting device, 6 ... Pressurizing device , 7... Cuff band, 7 a... Tube, 8... Left wrist, 8 a .. radial artery, 10 .. piezoelectric body, 11, 12 .. electrode, 7 B, 7 C 1, 7 C 2, 22. , 31, 32... Pressing part, 21.

Claims (6)

  A pulse wave measuring device comprising: a piezoelectric sensor and a pressing portion arranged to face a pulse wave measuring portion.   The pulse wave measuring device, wherein the pressing portion is arranged on the downstream side of the artery with respect to the piezoelectric sensor.   The pulse wave measuring device according to claim 1, wherein the pressing portion includes a convex portion that presses the artery.   The pulse wave measuring device according to claim 1, further comprising a pressure adjusting unit that adjusts at least a pressure applied to the artery by the pressing unit.   The pulse wave measuring device according to any one of claims 1 to 4, further comprising a fabric in which the piezoelectric sensor and the pressing portion are arranged side by side.   The pulse wave measuring device according to claim 1, wherein the pressing portion is formed of a hollow annular air bag disposed along a periphery of a living body part.

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