JPH02261423A - Pulse wave introducing apparatus - Google Patents

Abstract

PURPOSE:To get rid of unpleasant feeling accompanied with fitting and to reduce consumption of electricity by constituting an apparatus of a sensor part prepd. by pinching a sheet-like pressure-sensitive conductive rubber with a fixing plate and a pressure-transmitting piece and a fitting device pressing the pressure-transmitting piece on an epithelium of a wrist artery side. CONSTITUTION:A sensor part 1 consists of a sheet-like pressure-sensitive conductive rubber 2 transferring a pressure produced by a displacement of an outside epithelium B of a wrist artery A accompanied with a pulse of a living body to an electric resistance, a fixing plate 3 fixing the pressure-sensitive conductive rubber 2, and a pressure-transmitting piece 4 fixed on the upper face of the pressure sensitive conductive rubber 2. A fitting device 5 is fixed on the fixing plate 3 and consists of a well known belt fittable in such a way that the pressure transmitting piece 4 of the sensor part 1 is positioned on an outside epithelium B of a wrist artery. On the sensor part fitted on the wrist by means of a fitting device, as the pressure-transmitting piece thereof presses the epithelium of the wrist artery side, the pressure-sensitive conductive rubber pinched by the pressure transmitting piece and the fixing plate receives a pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse wave deriving device that detects changes corresponding to the pulse of a living body and converts the detected changes into electrical signals.

[Prior Art] During normal nighttime sleep, the pulse rate decreases as the person falls asleep, and increases during the waking period. Also, in general, nonrem (NR)
During the EM (EM) sleep phase, the pulse rate per unit time is stable, but during the REM (REM) sleep phase, the activity state of the autonomic nervous system is disrupted, and the pulse rate is known to fluctuate significantly. . Therefore, by detecting fluctuations in pulse rate, it is possible to not only estimate the sensor component of the biological rhythm during sleep, but also to estimate the REM sleep period. This also plays an important role in understanding the physiological state of living organisms during sleep.

By the way, when detecting the pulse rate of a living body, either the electrical potential changes that occur with the heartbeat are derived and expressed as an electrocardiogram, or the changes in the state of the living body that occur with the pulse are converted into electrical signals and derived. The pulse rate is calculated from the period of potential change obtained by expressing something as a pulse wave.

Conventionally, to obtain an electrocardiogram, a method has been used in which electrodes are attached to the skin at two or more points sandwiching the heart and the potential difference between the electrodes is measured. As a pulse wave deriving device, a photoelectric pulse wave sensor 10 as shown in FIG. 6 may be attached to the pad of a finger as shown in FIG. 8, or a photoelectric pulse wave sensor 10 as shown in FIG. 7 may be used. As shown in FIG. 9, it is attached to the earlobe and uses the fact that the amount of light emitted from the light emitting section 11 received by the light receiving section 12 changes due to changes in blood flow accompanying the pulse. A method of converting it into an electrical signal is used. The pulse wave electrical signal obtained by the sensor IO is normally input to the pulse rate counting device 14 via the lead wire 13. The arrangement of the light emitting part 11 and the light receiving part 12 may be a reflective type where they are placed next to each other on one side of the measurement site (see Figure 6), or a transmission type where they are placed on either side of the measurement site (see Figure 7).
is often used. Further, in the case of a reflective type, it is necessary to attach a light shielding body 15 as shown in FIG. 8 so as to wrap around the measurement site and the sensor 10 and prevent unnecessary light from entering from the outside.

[Invention tries to solve! III! I) However, in order to detect the pulse using the method described above, it is necessary to attach at least two electrodes to obtain an electrocardiogram, and depending on the type of electrode, sweating may cause a rash on the skin surface.
There have been problems in that decentralization is likely to occur, which increases the discomfort associated with wearing the sensor during long-term measurements, and that potential measurement is inhibited by polarization. In addition, in the method of obtaining a pulse wave curve using the photoelectric pulse wave sensor 10, there is no need to worry about polarization of the electrodes, but it is also possible to use the transmissive sensor 10 to pinch the earlobe, or to place the reflective sensor 10 on the outside of the finger to block light. There are problems such as discomfort caused by wearing the sensor because it is necessary to wear the sensor 15 on the body 15, and the number
There was a problem that a current of about 0 mA was required, and the power consumption of the measuring device could not be reduced.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a pulse wave deriving device that does not cause discomfort even when the sensor is worn for a long time, and can also reduce the power consumption of the device. It's about doing.

c! Means for Solving Ia] In order to solve the above-mentioned problems, the present invention provides a pulse wave deriving device including a sensor section in which a sheet-like pressure-sensitive conductive rubber is sandwiched between a fixing plate and a pressure transmitting piece; This device is characterized by comprising a mounting tool that presses the pressure transmitting piece of the sensor portion onto the epithelium on the wrist artery side.

[For production]

According to the above configuration, since the pressure transmitting piece of the sensor unit attached to the wrist with the mounting tool presses on the epithelium on the wrist artery side, the sensor unit feels as if it is pinched between the pressure transmitting piece and the fixing plate due to the pressure. Piezoconductive rubber is subjected to pressure. The pressure that the pressure-sensitive conductive rubber receives changes due to the displacement of the outer epithelium of the wrist artery caused by changes in blood flow in the wrist artery due to pulse beats. Therefore, since the electrical resistance of the pressure-sensitive conductive rubber also changes in accordance with the pulse, pulse waves can be derived.

〔Example〕

FIGS. 1 to 5 show an embodiment of the present invention, in which the sensor unit 1 detects wrist artery A, outer epithelium B, and
A sheet-shaped pressure-sensitive conductive rubber 2 that converts the pressure generated by the displacement of The fitting device 5 is a well-known belt that can be attached to the fixing plate 3 and worn so that the pressure transmitting piece 4 of the sensor section 1 is positioned on the outer epithelium B of the wrist artery. Become. In addition, 6 is a lead-out line connected to the pressure-sensitive conductive rubber 2, and 7 is a signal processing device connected to the lead-out line 6, which converts the electrical resistance of the pressure-sensitive conductive rubber 2 into an electric potential. It has a function of detecting the pulse rate from the cycle of potential changes and transmitting the output to a measuring device (not shown).

Here, the thickness of the pressure-sensitive conductive rubber 2 in the above embodiment is 0.5 to 1 m, and the fixing plate 3 is an acrylic plate approximately 1 m thick or a hard nylon belt (clothes cloth) approximately 0.5 m thick. The pressure transmitting piece 4 is made of a hard rubber-like material and has a trapezoidal cross section. Preferably, the wearer 5 has a convex curved surface, and the wearer 5 may be a belt using a well-known surface fastener or a watch strap. Note that the thickness of the sensor portion 1 is approximately 3 to 4 mm.

In the pulse wave deriving device configured in this manner, a pulse wave is derived by the operation described below.

The sensor part 1 is attached via a fitting 5 so that the pressure transmitting piece 4 contacts the outer epithelium B to the wrist artery, and the pressure sensitive conductive rubber 2 is connected to the fixed Fi, 3 for pressure transmitting. Since the pressure sensitive conductive rubber 2 is sandwiched between the pressure transmitting piece 4 and the pressure transmitting piece 4, pressure is applied to the pressure sensitive conductive rubber 2 through the pressure transmitting piece 4. At the same time, since the mounting tool 5 presses the sensor section 1 against the wrist, appropriate pressure is also applied to the outside of the wrist artery A.

The pulsation of the wrist artery A causes the outer wall of the artery to bulge or dent. As a result, the displacement is transmitted to the pressure transmitting piece 4 in contact with an appropriate pressure, and as a result, the pressure sensitive conductive rubber 2 receives pressure from the pressure transmitting piece 4, just as you touch your wrist with your fingers to check your pulse. As a result, the electrical resistance of the pressure-sensitive conductive rubber 2 changes. That is, each time the artery pulses, the epithelium B swells, the pressure that the pressure-sensitive conductive rubber 2 receives becomes stronger, and its electrical resistance decreases.

Therefore, by extracting the output of a circuit (which can be easily configured by the bridge method or resistance division method) that measures the electrical resistance of the pressure-sensitive conductive rubber 2, which varies as described above, it is possible to derive the pulse wave.

Considering the power consumed by the electrical resistance measurement circuit, the current required to generate a reference voltage corresponding to the reference resistance value is on the order of several mA at most.
It is possible to operate at a significantly lower power consumption than when a photoelectric sensor is used to cause an LED to emit light. Also,
The pressure transmitting piece 4 is made of a hard rubber-like material and has a trapezoidal cross-section, and the upper surface has a gently convex curve to prevent it from shifting from the position where it contacts the wrist artery A, thereby preventing excessive pressure on the wrist. It has the advantage of not being added.

〔Effect of the invention〕

As described above, the present invention includes a pulse wave deriving device including a sensor portion in which a sheet-like pressure-sensitive conductive rubber is sandwiched between a fixing plate and a pressure transmitting piece, and a pressure transmitting piece of the sensor portion on the wrist artery side. By using a device that presses against the epithelium, the displacement of the outer epithelium of the wrist artery due to the pulse can be converted into pressure applied to the pressure-sensitive conductive rubber, and the change in electrical resistance can be obtained as a pulse wave. In addition, pulse waves can be obtained simply by wearing the small and thin sensor section on the wrist like a wristwatch, which reduces the discomfort caused by wearing the sensor. Furthermore, in a circuit that measures changes in electrical resistance of pressure-sensitive conductive rubber, power consumption can be significantly reduced compared to when a photoelectric pulse wave sensor is used.

[Brief explanation of drawings]

Figures 1 to 5 show an embodiment of the present invention, in which Figure 1 is a partially sectional side view showing the pulse wave deriving device worn on the wrist, and Figure 2 is a perspective view of the sensor section. 3 is a perspective view showing an example in which the pulse wave deriving device worn on the wrist and the signal processing device are separated, and FIG. 4 is a perspective view showing an example in which the sensor unit and the signal processing device are both provided in the wearing tool. Figure 5 is a cross-sectional view of the wrist surrounding the same as above, Figures 6 and 7 are respectively perspective views showing conventional photoelectric pulse wave sensors, and Figure 8 is a sensor shown in Figure 6 attached to the finger. FIG. 9 is a perspective view showing the state in which the sensor shown in FIG. 7 is attached to the earlobe. 1...Sensor part, 2...Pressure-sensitive conductive rubber, 3...
・Fixing plate, 4... Pressure transmission piece, 5... Mounting tool, 6.
... Leading line, 7... Signal processing device.

Claims (1)

[Claims] (1) Equipped with a sensor section in which a sheet-like pressure-sensitive conductive rubber is sandwiched between a fixing plate and a pressure transmitting piece, and an attachment device that presses the pressure transmitting piece of the sensor section onto the epithelium on the wrist artery side. Pulse wave derivation device.