JPS5918052B2 - Pulse wave meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulse wave meter that detects pulse waves inside the body of a subject to be measured, and particularly to a pulse wave meter that is used to accurately detect pulse waves in blood vessels when brought into contact with the skin of a human body, which is a subject to be measured. The object of the present invention is to provide a small-sized detection device that is intended to transmit important information to the user.

The pulse waves of the human body are extremely delicate, and can be affected by psychological factors such as the happiness, anger, sadness, etc. of the person receiving the checkup, physical factors such as running, jumping, etc., or a combination of these conditions, as well as the person undergoing the examination. It changes subtly and noticeably due to changes in pathological organs and tissues within the body, and in the field of clinical medicine, which studies pathology and sanitary physiology of the human body, it is particularly important for diagnosing individual conditions of the human body. It is very meaningful to obtain information on the shape, size, regularity, etc. of the pulse wave of the human body.

Conventionally, as a means of obtaining pulse wave information of the human body, a specialized measurer such as a doctor applies pressure to an artery such as the carotid artery or radial artery of the human body with a fingertip over the skin, and the pulse wave information is transmitted through the fingertip. Measures were taken to obtain pulse wave information such as pulse rate, strength, and regularity by palpation.

However, this palpation diagnosis involves subtle changes transmitted through the fingertips, so it varies depending on various factors such as the way the artery is pressed and the pressure of the presser.Also, even on the same subject, different operators may be performing the measurement. For example, the method of obtaining pulse waves is different, and precise palpation cannot be performed quickly and easily by any doctor, but only by those with long experience.

Moreover, palpation had a major limitation in that it was not possible to record objective information about pulse waves.

The present invention was developed by the present inventors as a result of research to overcome the above-mentioned conventional drawbacks.The present invention has been developed as a result of research by the present inventors to overcome the above-mentioned conventional drawbacks. We have successfully developed a pulse wave meter that can accurately extract information by converting it into electrical signals using a highly sensitive semiconductor pressure-electric converter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pulse wave meter of the present invention will be described below as an example using FIGS. 1 to 7.

FIG. 1 is a perspective view of the pulse wave meter, and FIG. 2 is an assembled view of the pulse wave meter.

This embodiment of the plethysmograph consists of a band which is a bendable and stretchable flexible band that is used by wrapping around the radial artery of the forearm of the human body, and an air bag 2 with a rubber bulb pump attached integrally to the band 1. , a guide plate 3 attached to the air bag 2 , and a semiconductor pressure sensor 4 as a semiconductor pressure car electric converter according to the present invention, which is disposed so as to freely come into contact with the air bag 2 via the guide plate 3 . It consists of circuit 5.

The band 1 is formed of a vinyl band-like body that can be folded and stretched freely, and near both ends in the longitudinal direction, so-called Velcro tape 11 is adhesively fixed. It is wound around the radial artery and can be easily connected and locked between the Velcro tapes 11 at both ends.

The air bag 2 has a main body 21 formed of a flexible elastic material such as gope vinyl as shown in the partially cutaway explanatory view of the air bag in FIG. It consists of a rubber bulb pump 23 connected to a mounting body 21 by a pipe 22.

The air system main body 21 is formed into a flat rectangular body as a whole, and therein is a plurality of hollow cylindrical chambers 24 formed with approximately the same volume.
The hollow cylindrical chambers 24 are arranged adjacent to each other, and communicated between each hollow cylindrical chamber 24 by one common passage 25 for supplying and discharging air into each hollow cylindrical chamber 24. One end of the pipe 22 to be connected to the rubber ball pump 23 is opened inside, and the other end of the pipe 22 is connected to the inside of the rubber ball pump 23.

Therefore, the air supplied into the main body 21 through the pipe 22 is uniformly supplied into each hollow cylindrical chamber 24 by the passage 25, and each hollow cylindrical chamber 24 is supplied with air from a structure in which a plurality of cylindrical chambers are connected. When this is done, the air system main body 21 as a whole can be easily deformed along the curved peripheral surface of the guide plate 3 in the longitudinal direction.

Reference numeral 27 denotes cloth pieces fixed to both longitudinal ends of the air pack main body 21, and the air pack main body is fixed to the band 1 by attaching these cloth pieces 2γ to the band 1 by sewing or the like.

The rubber bulb pump 23 is an air pump with a check valve, and the rubber bulb pump 23 is an air pump with a check valve.
A known rubber bulb pump is configured to exhaust air by rotating a screw 26 provided at a connecting portion of the pump.
By holding the rubber bulb pump 23 in the palm of your hand and repeating pressure and release, the pump action pumps air into the pipe 2.
2 into the air chamber body 21, and by rotating and loosening the screw 26, the air inside the air chamber body 21 can be removed.

The guide plate 3 is formed by bending a rectangular thin plate of duralumin into a semicircular shape, and has a circular through hole 31 bored in the center thereof, the diameter of which is determined by the semiconductor pressure sensor 4 described later.
The diameter of the lower end of the outer cylinder of the semiconductor pressure sensor 4 is slightly larger than that of the semiconductor pressure sensor 4 so that the lower end of the outer cylinder can be slid freely in the axial direction.

The length of the guide plate 3 is such that when the pulse wave meter of this embodiment is attached to the radial artery of the forearm of a human body, it can be easily attached around the forearm, and the length of the guide plate 3 is determined based on the average thickness of the human arm. The guide plate 3 is formed to have a slightly thicker inner diameter indexed from the inner diameter, and when the air bag 2 is inflated and the guide plate 3 is pressed from the back side by pressure from the air bag main body 21 in the usage state described later. By deforming the guide plate 3 in the direction of the center of curvature, the guide plate 3 is formed in such a length that even when both longitudinal ends approach each other, they do not come into contact with each other and cause a problem, and the rlJ of the guide plate 3
is before.

The width is slightly wider than the width of the flat rectangular air chamber body 21 in the free expansion state to ensure the pressurizing effect of the air chamber body 21.

Reference numeral 32 denotes pieces of cloth fixed to both longitudinal ends of the guide plate 3. By attaching the cloth pieces 32 to the cloth pieces 27 of the air unit body 21 by sewing or the like, the guide plate 3 is locked to the air unit body 21.

The semiconductor pressure sensor 4 is a semiconductor strain-electric conversion element (hereinafter referred to as a strain-sensitive element) that utilizes the piezoresistance effect of a semiconductor.
This sensor incorporates a thin plate-like strain plate 41 made of silicon single crystal and has a sensing element 41a integrally formed therein.
An assembly 42 consisting of a pair of upper and lower support members 42 a and 42 b that sandwich and support the strain plate 41 from both sides is installed in the casing 43, and the upper surface of the assembly 42 is provided with a predetermined contact pressure receiving surface. Q I
Attached to the upper support member 42a via the J song 4b,
A hollow chamber formed between the membrane body 44a and the upper surface of the assembly 42 is liquid-tightly filled with silicone oil 44c.
A pressure transmitting chamber 44 is formed in the casing 43, and a lid body 45 having a window frame portion 45a that exposes the membrane body 44a to the outside is integrally fixed to the casing 43, and the pressure transmitting chamber 44 of the strain plate 41 and Outside air (
The external pressure applied to the pressure receiving surface of the membrane body 44a is transmitted to the strain sensing element 41a on the strain plate 41 via the pressure transmission chamber 44, and the strain sensing element 41a The electrical output is taken out to the outside through a connector 46.

More specifically, the strain plate 41 made of semiconductor silicon single crystal is an ultra-compact, ultra-thin piezoelectric transducer developed by the applicant's research institute, and has a plate thickness of 0.038 mm, a length of 5 mm, and a width of 5 mm. It is formed into a 6 mm rectangle, and in the center of its surface are two pairs of P-type silicon strain sensing elements, a signal transmission section connected to these, and an electrode section connected to the signal transmission section. The sensor is formed integrally with a silicon base and has a high sensitivity that can detect pressures up to 0.5 atmospheres.

This strain plate 41 is supported by upper and lower support members 42a.

42b, the periphery thereof is clamped and fixed, and the central part, which is the non-fixed part, is configured as a strain-generating part that deforms under pressure, and a strain-sensor is integrally formed on the strain-generating part as described above. The element 41a is designed to generate an electrical signal change based on a piezoresistance effect that is proportional to the amount of distortion in the strain-generating portion depending on the amount of pressure.

One upper support member 42a (upper support member in FIG. 4)
is formed into an annular member having a circular through hole 42c in the center using cordierite (trade name) whose thermal expansion is almost equal to that of the strain plate 41, and the through hole 42c is formed on the surface that comes into contact with the strain plate 41.
An annular groove 42d is carved concentrically with the groove 4.
2d is a blank space for connecting the head 42f of the lead pin 42e and the electrode from which the signal of the sensing element 41a of the strain plate 41 is taken out with a gold wire 42g.

The other lower support member 42b (lower support member in FIG. 4)
The same cordierite (trade name) as the support member 42a is used, and the hole is made thicker than the upper support member, and in the center, the upper part is formed to have approximately the same size as the center hole 42c of the upper support member 42a. A stepped through hole 42h, which communicates with a through hole whose lower part is formed to have a smaller diameter, is formed in an annular member bored concentrically with the through hole 42c of the upper support member 42a. The strain plate 41 of the semiconductor pressure sensor 4 is sandwiched and supported opposite the upper support member 42a.

Five through holes 42e1 are bored along the circumference of the annular portion of the lower support member 42b at appropriate intervals at positions corresponding to the grooves 42d of the upper support member 42a.
Insert the lead pin 42e into 2e1, and
The head 42f is inserted into the groove 42d of the upper support member 42a.
A lead wire 42g having one end connected to an electrode portion on the strain plate 41 is connected to the lead wire 42g, and the other end of the lead pin 42e is made to protrude below the lower support member 42b. A lead wire 41 whose one end is connected to a terminal of a connector 46 is connected.

By the way, as mentioned above, the strain plate 41 and the upper and lower support members 42a,
42b is mounted within a casing 43 as shown.

The casing 43 is made of duralumin, and has a protruding upper outer peripheral portion to form a flange portion 43a, and has a concentric ring shape 02 on the inner peripheral surface, the outer edge of which becomes smaller in inner diameter in the axial direction.
The inner diameter of the lower step 43b is the same as that of the lower support member 42b.
The outer diameter of the casing 43 is approximately the same as that of the casing 43.
The assembly 42 is stably fitted onto the lower step portion 43b.

An O-ring 44b made of an elastic material such as rubber and having an outer diameter approximately equal to the outer diameter of the upper support member 42 is mounted on the upper surface of the L-portion support member 42a of the assembly 42. A space formed by the inner circumferential surface of the O-ring 44b and the upper surface of the upper support member 42 is densely filled with silicone oil 44c having a viscosity (350 cst).
4b A circular membrane body 44 made of flexible and thin vinyl chloride formed to have a diameter slightly smaller than the outer diameter.
It is placed concentrically with the ring 44b so that its outer circumferential portion is covered with the outer circumferential surface of the membrane body 44b, and the cover body 45 is placed over the membrane body 44a from above.

The lid body 45 is made of duralumin and has an annular window frame portion 45a that projects toward the axis in the diametrical direction and an annular hanging portion 45b that projects downward in the thickness direction. The external shape is a truncated cone, and a flat annular window frame edge 45c is formed at the top of the truncated conical shape, and the axis of the cylindrical central window formed by the annular window frame 45a is aligned with the semiconductor pressure sensor 4. The lid body 45 is placed on the membrane body 44a so as to coincide with the axis of the strain plate 41, and the annular hanging portion 45b of the lid body 45 is attached to the upper and lower support members 42a of the assembly 42.
Bolt penetrations are inserted into the gap formed between t 42 b and the upper step portion 43 c of the casing 43 and are further drilled at equal intervals along the circumference of the thick outer peripheral portion of the lid body 45. The holes 45d are aligned with the bolt through holes 43d drilled at equal intervals along the circumference of the flange portion 43a of the casing 43, and the bolts are inserted and screwed into the through holes 43d and 45d to close the lid. By tightening the body 45 and the casing 43, the lower inner edge of the window frame portion 45a of the lid body 45 is pressed from above the membrane, thereby pushing the membrane body 44a onto the O-ring 44.
As the O-ring 44b is brought into fluid-tight contact with the O-ring 44b and the silicone oil 44c moves as the O-ring 44b deforms, the portion of the membrane 44a corresponding to the open central window is bulged out in a hemispherical shape above the window. .

A connector 46 is screwed through the side wall of the casing 43, and a lead wire 47 connects the terminal facing inside the casing 43 of the connector 46 and the lead pin 42e. A plug 48 can be connected to the side protruding from the side.

Further, reference numeral 49 denotes a disk-shaped back cover which is screwed onto the lower end of the casing 43, and has a communication hole 49a in its axial center to introduce the atmosphere.

By the way, in the semiconductor pressure sensor 4 having the above-mentioned configuration, the diameter of the outer peripheral part of the casing 43 is set to the center hole 3 of the guide plate 3.
The inner diameter of the casing 4 is slightly smaller than that of the casing 4.
3. The outer peripheral part of the casing 43 is loosely inserted into the central hole 31, and the connector 46 provided on the outer peripheral part of the casing 43 is connected to the air system main body 2.
1 and the guide plate 3, and connect the plug 48 to the connector 46, so that the lateral movement of the semiconductor pressure sensor 4 is restrained by the inner wall of the guide plate center hole 31, but the axial movement is restricted. When the semiconductor pressure sensor 4 moves in the axial direction, the connector 46 and the plug 48 are engaged with each other at the edge of the central hole 31 of the guide plate 3, thereby preventing the semiconductor pressure sensor 4 from moving away from the guide plate 3. It is arranged so that it can be used.

The display circuit 5 is a circuit that separates an input electric signal into a DC component and an AC component and displays them separately.As shown in FIG.
Connected to a.

That is, the display circuit 5 has the first, second, third, fourth, and fifth display circuits.
input terminals 51a, 51b, 51c.

51 d t 51 e, and the first input terminal 51 a
is grounded, and the fourth input terminal 51d is a variable resistor 5 for voltage adjustment.
Connect to 2.

The voltage adjustment variable resistor 52 is a variable resistor that adjusts the supplied voltage to a predetermined voltage, and one terminal 52a is connected to the fourth input terminal 51d and the other terminal 52b is connected to the next stage power supply 53. .

The power source 53 is a stable DC power source, and is a general power source AC 1.
This is a power supply designed to rectify 00V and supply a stable DC voltage compensated for power fluctuations, and a terminal 53a of the power supply 53 is connected to the other terminal 5 of the voltage adjustment variable resistor 52.
Connect to 2b.

A sliding resistor 54 for voltage balance adjustment is connected between the second input terminal 51b and the third input terminal 51c, and the sliding terminal 54a of the voltage balance adjustment sliding resistor 54 is used for temperature compensation in the next stage. Connect to circuit 55.

The temperature compensation circuit 55 adjusts the passing current by successively changing resistance according to temperature changes, and is composed of a circuit in which a fixed resistor 55a and a thermistor 55b are connected in series, and is used for pressure transmission of the semiconductor pressure sensor 4 described above. Expansion due to temperature change of silicone oil 44c sealed in chamber 44,
The input terminal 55c of the temperature compensation circuit 550 is connected to the sliding terminal 54a of the voltage balance adjustment sliding resistor 54 in the previous stage, and is used to compensate for the influence of contraction on the strain pressure receiving element 41a of the semiconductor sensor 4. The end 55d is connected to the next stage differential amplifier 56.

The differential amplifier 56 has first and second input terminals 56a, 56.
b, and the first and second input terminals 56 a t 56
The first input terminal 56a of the differential amplifier 56 is connected to the front stage. is connected to the output terminal 55d of the temperature compensation circuit 55, and the second input terminal 56
b is connected to the fifth input terminal 51e described above.

The output terminal 55c of the differential amplifier 56 is connected to a variable capacitor 57 at the next stage and a smoothing circuit 58 at the next stage.

The variable capacitor 51 has the function of cutting the DC component and passing only the AC component, and can also adjust the time constant (adjusted with the resistance of the recorder, which will be described later). It is connected to the output terminal 56c of the dynamic amplifier 56, and the output terminal 57b is connected to the recorder 59 at the next stage.

The recorder 59 is called a pen-writing recorder, and records on a recording paper in an analog manner by following the time change using an input voltage signal. It is connected to the output end 57b.

The smoothing circuit 58 described above has a function of smoothing an alternating current component into a direct current component, and is a circuit consisting of a choke coil 58a and two capacitors 58b and 58c, and the input terminal 58d of the smoothing circuit 58 is Front stage differential amplifier 5
The output terminal 58e is connected to the DC voltmeter 501 of the next stage.

The DC voltmeter 501 displays the input DC voltage in analog form, and the display section of the DC voltmeter has equally spaced scales engraved with pressurizing force, and also has a range changeover switch that can expand the scale range at any time. The input end 501a of the DC voltmeter 501, which is a convenient additional meter, is connected to the output end 58e of the smoothing circuit 58 at the previous stage.

Note that the recorder 59 and DC voltmeter 501 described above
The output ends of each are grounded.

Thus, the first, second, third, fourth and fifth input terminals 51a, 51b, 51c of the display circuit 5.

51d and 51e are the first, second, third, fourth, and fifth outputs of the circuit shown in FIG. 6 (description is omitted) in which the strain pressure receiving element 41a arranged in the semiconductor pressure sensor 4 is connected to a bridge circuit. Terminal 41al.

41a2, 41a3, 41a4, and 41a5.

Next, the effects of the pulse wave meter of this embodiment will be explained together with the embodiment shown in FIG. 7.

First, when detecting a pulse wave using this pulse wave meter, the membrane body 44a of the semiconductor pressure sensor 4 is brought into contact with the part corresponding to the radial artery part B on the forearm part A, while facing the part corresponding to the radial artery part B. The guide plate 3 is fitted around the forearm part A, the belt 1 is wound around it, and it is secured with the Velcro tapes 11 at both ends.

Next, operate the rubber ball pump 23, and
By supplying air into the air unit main body 21, the air unit main body 2
1, the tip of the semiconductor pressure sensor 4 is pressed toward the radial artery B from the skin of the radial artery in the forearm.

By doing this, the pulsation of the radial artery portion B is transmitted to the membrane body 44a disposed at the tip of the semiconductor pressure sensor 4, and the transmitted pulsation changes are transmitted to the pressure transmission chamber 4 of the semiconductor pressure sensor 4.
4 is transmitted to the semiconductor strain sensing element 41a via the silicone oil 44c, where it is converted into an electrical signal, and the electrical signal is input to the display circuit 5 where it is separated into a DC component and an AC component and displayed. .

That is, the pressure exerted by the semiconductor pressure sensor 4 on the forearm A by the rubber bulb pump 23 is displayed as a DC component, and the pulse wave itself is displayed as an AC component.

By the way, the semiconductor pressure sensor 4 has a sensing element 41a that converts pressure into an electric signal and is integrally formed with the strain plate 41, so it can be made ultra-thin and ultra-small, and has high sensitivity. Even when pressure changes, an electrical signal proportional to the pressure change can be faithfully converted.

Furthermore, an assembly 42 consisting of a strain plate 41 and a pair of support members 42a and 42b that sandwich and support the strain plate 41 from both sides is installed in the casing 43, and the upper surface of the assembly 42 has a thin wall with a predetermined pressure receiving surface. The flexible membrane body 44a is attached to the O ring 44b.
The hollow chamber formed between the membrane body 44a and the upper surface of the upper support members 42a and 42b is filled with incompressible silicone oil 44c. A lid body 45 that forms a pressure transmission chamber 44 and has a window portion that exposes the membrane body 44a to the outside is integrally pressed and fixed to the casing 43, so that pressure, that is, pulsation, is applied to the membrane body from the outside. The pressure is transferred to the pressure transmission chamber 4 through the incompressible silicone oil 44c.
A uniform internal pressure is transmitted to the entire interior of 4.

The periphery of the inside of the pressure transmission chamber 44 is covered with a lid 45, which is compressed and compressed.
Since the ring 44b is surrounded by the upper support member 42a of the assembly 42 and the free expansion within the pressure transmission chamber 44 is restricted, the internal pressure transmitted within the pressure transmission chamber 44 is not relieved, so that the internal pressure is applied to the strain plate 41 on which the strain sensing element 41a is arranged without being attenuated.

Moreover, since an incompressible fluid such as silicone oil 44c is sealed in the pressure transmission chamber 44, the pressure transmission chamber 44 can be
4, and can be directly transmitted to the semiconductor strain plate 41, and errors due to the position where the external pressure is applied can be almost eliminated, so that measurement accuracy can be improved.

Since the membrane body 44a to which external pressure is applied is made of a material that is flexible and has a predetermined strength, the membrane body 44a can adapt to the skin surface of the forearm A, which is the subject to be measured. The applied pulse pressure can be accurately transmitted to the internal pressure transmission chamber 44 without delay, and it can also withstand a certain degree of mechanical strength.

In addition, since the size of the window portion of the lid body 45 is increased to a certain extent, the area of mlJffl can be increased to compensate for the decrease in sensing ability due to positional deviation, and the contact position can be easily selected. 45 window frame portion 45a
Since the more protruding membrane body 44a is formed in a hemispherical shape,
Since the area of the contact portion can be made smaller than that of other shapes, the influence from areas other than the desired measurement area can be minimized.

Further, since the atmosphere can be introduced to the back surface of the strain plate 41 through the communication hole 49a of the cylindrical back cover 49 which is screwed to the lower end of the casing 43, the pulse wave is can be measured.

Therefore, even during long-term measurements, stable measurements can be made without pressure compensation.

In this embodiment, the lid body 45 and the casing 43 are made of duralumin, so the semiconductor pressure sensor 4 body is lightweight, easy to process, and has strong strength and acid and alkali resistance. It has the advantage of being resistant to human body secretions such as sweat.

Even if the periphery of the semiconductor pressure sensor 40 shown in the embodiment is grasped by hand and the tip membrane 44a of the semiconductor pressure sensor 4 is pressed against the skin area on the radial artery of the forearm of a human body, the radial artery can be used. Although it is possible to detect the pulsation in part B,
However, it is extremely difficult to accurately detect pulsation changes because the holding state becomes extremely unstable due to hand shake, etc.

However, in the present invention, since the semiconductor pressure sensor 4 is supported by the flexible band 1 which can be bent and retracted via the guide plate 3, the curved part of the guide plate 3 is connected to the forearm. A, and the tip membrane 44a of the semiconductor pressure sensor 4 is brought into contact with a site on the skin corresponding to the forearm A and the radial artery B of the subject to be measured, and the band 1 is placed along the guide plate 3. The semiconductor pressure sensor 4 can be easily held at a desired location by wrapping it around the forearm A from the outside and securing it using Velcro tape 11 that is adhesively fixed near both ends in the longitudinal direction. It can be held stably for a long time without shifting its position even if it moves slightly.

Further, the degree of pressurization can be arbitrarily selected and adjusted depending on the condition of the band 1's eyelashes.

In addition, in the embodiment, since it is made of vinyl so as not to give the subject a strange sensation of touch, it also helps to maintain a stable state without stimulating the mental state of the subject.

Thus, the pulsations in the forearm A and the radial artery B propagate through the pressure transmission chamber 44 from the tip membrane 44a of the semiconductor pressure sensor 4, and are affected by the piezoresistance effect of the strain sensing element 41a on the semiconductor strain plate 41. The electrical signal is converted into an electrical signal based on the signal, and the electrical signal can be led to the outside via the lead pin 42e and the connector 46.

Note that since the semiconductor pressure sensor 4 is attached to the band 1 and is wrapped around and locked to the part to be measured, unless the band 1 is removed, the semiconductor pressure sensor 4 can be fixed to the same part with the same pressing force. - Minute changes in pulse waves under pressure can be measured over a long period of time.

By the way, in the above explanation, the focus has been given on the effects of the combination structure of the flexible strip and the semiconductor pressure car electrical converter of the present invention, but the present invention also focuses on the operation and effect of the combination structure of the flexible strip and the semiconductor pressure car electric This advantage can be further enhanced by interposing a fluid suppressing means between the semiconductor pressure car electric transducer and the transducer so that the tip of the thin film part contacts the object to be measured and presses it toward the object to be measured. Further reference will be made to the effects of the illustrated embodiment using the pumped air bladder 2 as the fluid suppression means.

The air system body 21 disposed between the band 1 and the guide plate 3 in FIG. A plurality of hollow cylindrical chambers 24 formed in
If the air is forced to be fed through the common passage 25 using a pressure pump, the air is uniformly supplied into each hollow cylindrical chamber 24, and the air is uniformly and gradually expanded as a whole.

Therefore, as described above, the tip membrane body 44a of the semiconductor pressure sensor 4 is brought into contact with the skin where the radial artery part B of the forearm A is located, and the position of the semiconductor pressure sensor 4 is adjusted using the band 1 onto the desired measurement site. After holding it, ``Rubber bulb pump 23''
When the air is forced into the air unit body 21 from the supply passage through the pipe 22 by hand, the air unit body 21 gradually expands along the curved surface of the guide plate 3. However, the bottom surface of the casing 43 of the semiconductor pressure sensor 4 is
The semiconductor pressure sensor 4 is pressed by the part of the air device main body 21 that comes into contact with this, and the semiconductor pressure sensor 4 is moved upward in the axial direction within the hole 31 of the guide plate 3.
The tip membrane body 44a is gradually pressed onto the skin surface of the forearm A.

Furthermore, if the supply of air to the air unit main body 21 is increased,
The pressing force of the semiconductor pressure sensor 4 on the forearm part A further increases, and it is caused by the pressure transmission chamber 44 of the semiconductor pressure sensor 4.
However, when the pressing force of the window frame portion 45a increases, the surface of the tip window membrane member 44a of the semiconductor pressure sensor 4 increases, and the window frame portion 45a becomes flattened by the flat surface formed on the upper surface. It acts as a stopper to the extent that it is pressed down to almost the same plane as the annular window frame edge 45c, and prevents the pressure in the pressure transmission chamber 44 from increasing due to further increase in pressing force.

Note that when supplying air to the air device main body 21, the surface that supports the internal pressure of the air device main body 21 is not only the rectangular external surface (but also the partition walls of each hollow cylindrical chamber 24 arranged inside). Because it is supported, it can withstand excessive internal pressure, and the rectangular body will not deform into a ball shape due to excessive internal pressure, and will never expand or contract in an distorted manner. A desired pressing force can be applied to the semiconductor pressure sensor 4 while maintaining contact with the semiconductor pressure sensor 21.

The amount of air supplied into the air unit body 21 is determined by the rubber bulb pump 2.
3, and the removal of air from the air bag 2 can be adjusted freely by rotating the screw 26, so press the tip of the semiconductor pressure sensor 4 onto the forearm A. The pressing force can be controlled arbitrarily,
It is possible to detect changes in the pulse wave at each step when the pressing force is sequentially increased or decreased, and by stopping the air supply midway, the pressing force can be reduced. It is also possible to detect the pulse wave under certain conditions while maintaining it at a constant value, which is very convenient in practice.

Of course, the output signals of the pulse wavemeters shown in FIGS. 1 to 4 can be observed using a conventionally known processing circuit, for example, by displaying the pulse wave shape on an oscilloscope. However, in conventional circuits, the output signal of the pulse wave meter is the sum of the changes in the internal pressure of the pressure transmission chamber 44 of the semiconductor pressure sensor 4 due to changes in the pressing force and the changes in pure pulse pressure. Since it is output, there is a drawback that it is not possible to detect how the pulse wave changes in correlation with the pressing force.

However, this drawback arises when the circuit shown in FIG. It is a dog that brings about effects and contributes in the field of clinical medicine.

That is, the semiconductor pressure sensor 4 uses a stable power supply 53 disposed in the display circuit 5 to set a predetermined DC voltage to the pressure receiving element 4 of the semiconductor pressure sensor 4 using a voltage adjustment resistor 52.
1a is provided to the bridge circuit.

In this way, the pressure change is converted into an electrical signal by the piezoresistance effect of the strain pressure receiving element 41a of the semiconductor pressure sensor 4,
It is guided to the display circuit 5.

In the display circuit 5, one input signal is input to a voltage balance adjustment sliding resistor 54 and a temperature compensation circuit 55.

The temperature compensation circuit 55 sequentially changes resistance according to temperature changes in order to compensate for the influence of expansion and contraction of the silicone oil 44c disposed in the semiconductor pressure sensor 4 on the strain pressure receiving element 41a due to temperature changes. The signal compensated for the change is input to one input terminal 56a of the next-stage differential amplifier 56.

The other signal is directly connected to the other input terminal 56 of the differential amplifier.
Enter b.

The differential amplifier 56 has first and second input terminals 56a, 56.
Since it has the function of subtracting the voltage signal input to b, amplifying the voltage by a predetermined amplification degree, and outputting it, the input voltage signal is subtracted and the voltage is amplified by a predetermined amplification degree. Variable capacitor 57 and smoothing circuit 58 are expanded in width and are in the next stage.
Output to.

Since the variable capacitor 57 has the function of cutting off the DC component and passing only the AC component, the DC component included in the output signal of the differential amplifier 56 at the previous stage is completely cut, and only the AC component is sent to the recorder 59 at the next stage. Output.

The recorder 59 records changes over time on a recording paper, and records the alternating current signal from the front variable capacitor 57, that is, the membrane 44a of the semiconductor pressure sensor 4, on the forearm A of the subject. A pulse wave signal detected by pressing on the skin of the radial artery region B is described.

Further, the smoothing circuit 58 has a function of smoothing an alternating current component into a direct current component, and all alternating current components included in the output signal of the differential amplifier 56 in the previous stage are smoothed and converted into direct current components in the next stage. output to the DC voltmeter 501.

The DC voltmeter 501 displays the input DC voltage in analog form, and the display section of the DC voltmeter 501 has equidistant scales engraved with applied pressure, so the DC component from the smoothing circuit at the previous stage is The signal, that is, the suppression signal generated by pressing the membrane 44a of the semiconductor pressure sensor 4 from the skin of the forearm A and the radial artery B of the subject to be measured, is displayed in analog form. The degree of pressing force with which the membrane 44a of the semiconductor pressure sensor 4 is pressed onto the skin of the subject can be detected.

FIG. 8 shows some clinical examples in which pulsation changes in the radial bone B were detected using the pulse wave meter of this embodiment and the circuits shown in FIGS. 6 and 5.

In other words, FIGS. 8a to 8e show changes in pulse waves measured over time on the horizontal axis when the electrical output (unit: V) is a constant pressing force.
The magnitude of the pulse wave is plotted on the vertical axis and displayed on a pen recorder. Figure 8a shows the pressing force of 0.5V and b shows the pressing force of 2. When OV, C is the pressing force 3. It shows changes in the pulse wave during OV, and as can be seen from this, in this clinical case, the pressing force was 2. The most detailed pulse wave was observed during OV.

The pressing force that allows the closest observation of pulse waves varies depending on the person.
When using this pulse wave meter, please check the air system body 2.
By adjusting the air supply to 1, you can discover the best pressing force state, and while maintaining that state, you can make stable observations over a long period of time.It is also useful because you can measure the relationship between the pressing force and pulsation. be.

Although the present invention has been described above with reference to embodiments, the present invention is not limited to the embodiments described above (it is possible to take several further embodiments).

For example, an example was shown in which a plastic bag strip was used as the band, but in short, it can be easily wrapped around the object to be measured.
Any flexible band-like body that can easily hold the contact surface of a semiconductor pressure sensor on a desired measuring part may be used, such as a connecting metal body such as a watch band, a clasp or a clasp. Other wrapping means may be substituted, such as perforated cortices.

Further, in the semiconductor pressure sensor in the above embodiment, the wall of the pressure transmission chamber is constituted by a lid body and an O-ring upper support member,
We have explained an example in which silicone oil is sealed inside and a strain plate with a semiconductor pressure sensor is exposed in the pressure transmission chamber, but the point is that the external pressure applied to the membrane at the tip is filled with an incompressible fluid. Any structure is sufficient as long as the pressure can be accurately transmitted to the semiconductor strain sensing element via the pressure transmission chamber.

Furthermore, in the above embodiment, an example using a guide plate has been shown, but it is also possible to eliminate the guide plate and attach the semiconductor pressure sensor to the air device main body by an appropriate coupling means.

In short, it is only necessary to mount the semiconductor pressure sensor in such a way that it moves in the axial direction due to the expansion and contraction of the air bag, but does not shift in other directions.

Furthermore, we showed an example of using an air bag as a suppression means,
The suppressing means is not limited to air, and may be a suppressing means using fluid. In short, any suppressing means that increases the pressing force gradually and uniformly may be used.

Further, in the example, an example of pulse wave measurement at the radial artery in the forearm of a human body was described, but the measurement site is not limited to this.
For the measurement of the carotid artery, the same configuration may be used, but the size of the guide plate and band are adjusted to match the carotid artery.

Furthermore, the pulse wave meter of the present invention is not limited to the human body, and can also be applied to and measure objects in which pulsations are present inside the object to be measured.

In summary, the present invention is a pulse wave meter suitable for accurately detecting and observing and recording pulsations existing in the body of a human body or other measured object using a semiconductor pressure car electrical transducer, and which is a flexible pulse wave meter. A strain-generating plate consisting of a band-like body and a semiconductor pressure car electric conversion device attached to the band-like body, and formed from a strain-generating plate provided with the semiconductor pressure-car electric conversion element, the thin film portion, the strain-generating plate, and a peripheral wall surface. At the same time, the strain plate has a pressure transmission chamber that is liquid-tightly filled with an incompressible fluid, and one surface of the strain plate is in contact with the incompressible fluid, and the other surface is in contact with the outside air. It will come to pass.

When using the pulse wave meter of the present invention, by wrapping the flexible band around the object to be measured, the thin film portion at the tip of the semiconductor pressure car electric transducer can be easily attached to a desired location on the object to be measured. This state can be maintained stably by suppressing contact, and fluctuations in pulsation applied to the thin membrane at the tip by the object to be measured are evenly propagated into the pressure transmission chamber filled with incompressible fluid. This signal is reliably detected by the semiconductor strain sensing element disposed inside the pressure transmission chamber, converted into an electrical signal, and taken out. By displaying the pulsation using a recorder, etc.), it is possible to accurately detect even minute fluctuations in the pulsation within the body to be measured.

The pressure-receiving surface is a flexible thin film part that comes into contact with the object to be measured, so it fits well with the part of the object to be measured.

Moreover, since the pressure-receiving part has a protruding shape, when it is pressed against the measurement site of the subject, instead of applying pressure to the skin as a whole when pressed against a flat surface, the normal-pressure part sinks under the skin, allowing the arterial artery to sink under the skin. It can be placed close to blood vessels.

Therefore, the pulse wave meter of the present invention exhibits excellent sensing ability.

In addition, in the pulse wave meter of the present invention, the semiconductor pressure car electric converter is further placed between the flexible band-like body and the semiconductor pressure car electric converter, and the tip thin film portion is brought into contact with the covered body 11J9. By adopting a configuration in which a fluid suppression means to be pressed toward the object to be measured is interposed, the pressing force on the object to be measured can be actively controlled arbitrarily using the fluid suppression means,
Therefore, it is useful to be able to detect the state of pulsation changes within the body to be measured due to fluctuations in the pressing force.

The pulse wave meter of the present invention can detect the output signal of the semiconductor pressure car electrical converter using a conventionally known processing circuit equipped with a display device such as an oscillograph. By using the circuit that processes the electrical signal from the pressure car electric converter in combination with a circuit that separates the electric signal into a DC component and an AC component, changes in the static pressure in the pressure transmission chamber of the semiconductor pressure car electric converter can be realized. In other words, the thin membrane at the tip of the semiconductor pressure car electrical transducer device simultaneously separates and accurately detects the pressure that presses the object to be contacted and the pulsation existing within the object to be contacted. Therefore, the quantitative relationship between the pressing force and the pulsation can be accurately observed, which is useful in practice.

In particular, if the human body is selected as the subject to be measured by the pulse wave meter of the present invention, it will be possible to accurately detect pulsations occurring in various parts of the human body such as the arms and neck, thereby contributing to the field of clinical medicine. It's large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a pulse wave meter according to an embodiment of the present invention, and FIG.
The illustrated assembly diagram of the pulse wave meter, FIG. 3 is a partially cutaway explanatory view of the air chamber body of the pulse wave meter of the same embodiment, and FIG. 4 is a longitudinal cross-sectional side view of the semiconductor pressure sensor of the pulse wave meter of the same embodiment. 5 and 6 are wiring diagrams showing the display circuit of the pulse wave meter according to the embodiment of the present invention, and FIG.
The figures are explanatory diagrams showing how the sphygmograph according to the embodiment is used, FIGS. 8a and 8b. C is a diagram showing an example of detecting and recording a pulse wave in the radial artery of the forearm of a human body using the pulse wave meter of the embodiment. In the figure, 1... band, 2... air bag,
3...Guide plate, 4...Semiconductor pressure sensor, 44a...Membrane body, 44...Pressure transmission chamber, 41...Start Distortion plate, 5...display circuit.

Claims (1)

[Scope of Claims] 1. Consisting of a flexible band-shaped body and a semiconductor pressure car electrical conversion device attached to the band-shaped body, semiconductor pressure car electrical conversion is performed by wrapping the flexible band-shaped body around a measured object. A pulse wave meter in which the thin membrane at the tip of the device is pressed into contact with the object to be measured, and the pressure pulsations existing in the object to be measured are converted into electrical signals by a semiconductor pressure car electrical converter and detected. The semiconductor pressure car electrical transducer attached to the body includes a flexible thin film portion having a protruding pressure receiving surface at its tip to be in contact with the object to be measured, and a strain plate provided with a semiconductor strain-electrical conversion element. It is formed by the thin membrane portion, the strain plate, and a peripheral wall surface, and is composed of a pressure transmission chamber in which an incompressible fluid is filled and held in a liquid-tight manner, and the strain plate has one surface formed by the strain plate. A pulse wave meter characterized by having one side in contact with a compressible fluid and the other side facing the outside air. 2. In the sphygmograph according to claim 1, between the flexible strip and the semiconductor pressure car electrical transducer, the thin film portion at the tip of the semiconductor pressure car electrical converter is directed toward the object to be measured. A flexible band-shaped body is wrapped around the object to be measured, and the thin film portion at the tip of the semiconductor pressure car electric transducer is brought into pressure contact with the object to be measured by means of the fluid suppression means. A pulse wave meter characterized in that pressure pulsations existing in a measured object are converted into electrical signals and detected by a semiconductor pressure converter. 3. In the pulse wave meter according to claim 2, a circuit is provided to separate the electrical signal from the semiconductor pressure car electrical converter into a direct current component and an alternating current component, and the pulsation of pressure existing in the object to be measured is converted into the above-described signal. 1. A pulse wave meter, characterized in that the pressure exerted by the tip thin membrane portion pressing against the object to be contacted is detected as a direct current signal using an alternating current signal.