JP3346852B2 - Pulse detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse detecting device for detecting a pulse .

[0002]

2. Description of the Related Art As a device for detecting a pulse (here, the term "pulse" is used to include a heartbeat), an electrocardiograph, a blood flow at a fingertip, an ear lobe, or the like is optically measured. There are provided detectors and detectors based on arterial pulsations.

[0003]

However, in the electrocardiograph, an electrode must be connected to a living body, and an electrocardiograph for detecting blood flow optically and for detecting it from pulsation is an electrocardiograph. Although the pulse can be measured more easily than in the above, the measurement site is limited. The present invention has been made in view of such a point, and an object of the present invention is to provide a pulse detection device that can more easily perform a pulse measurement.

[0004]

A pulse detecting apparatus according to the present invention comprises a vibration sensor for detecting a bone vibration of a living body and a discriminator for discriminating a pulse waveform from an electric vibration signal output from the vibration sensor. It is characterized by having the following.

[0005]

According to the present invention, in order to detect a pulse from bone vibration of a living body, the pulse can be detected without any limitation on the part to be measured. As a vibration sensor for detecting bone vibration, a sensor such as a piezoelectric element can be used, and a flexible optical fiber having a core portion made of silicon in a gel state and a cladding portion made of a transparent fluorine elastomer, and the like. A light emitting element provided at one end and a light receiving element provided at the other end of the optical fiber can be used.

[0006] The mounting site of the vibration sensor is not limited, but it is of course more preferable that there is less muscle or fat between the skin and the bone to be brought into contact with the vibration sensor.

[0007]

FIG. 1 is a block circuit diagram of a pulse detecting device according to the present invention. A vibration sensor 2 that picks up the vibration of the bone 11 and converts it into an electric vibration signal, an amplifier circuit 30 that amplifies the electric output of the vibration sensor 2, a hum noise removal circuit 31, and a pulse waveform extracted from the vibration signal And a discrimination circuit 4.

As the vibration sensor 2, a piezoelectric element and a resistance bridge connected thereto are generally considered. As shown in FIG. 3, an optical fiber 20 and a light emitting diode arranged at one end of the optical fiber 20 are used. A light-emitting element 21 and a light-receiving element 22 such as a photodiode disposed at the other end of the optical fiber 20 may be used. In this case, the light-emitting element 21 is connected to the amplifier circuit 30 via a current-voltage conversion circuit. I do.

When the optical fiber 20 is disposed along the skin 10 on the surface of the living body, the optical fiber 20 is also bent along the curved surface of the living body. However, a loss of the light amount occurs at the bent portion, and the bending due to the vibration is caused. Since the loss light amount changes with the change, bone vibration can be detected. At this time, since the optical fiber 20 is fitted to a living body having many curved surfaces, and the longer the length, the higher the detection sensitivity, the core 23 of the optical fiber 20 is a gel-like highly transparent silicon, and the cladding 24 is a fluoroelastomer. The one having the flexibility of In addition, a material having flexibility is less likely to cause discomfort when the vibration sensor 2 is brought into contact with a living body, does not cause pain, and is extremely preferable as a device for picking up bone vibration. When the influence of extraneous light is conceivable, it is preferable to use far-infrared light for the light emitting element 21 and the light receiving element 22.

The discriminating circuit 4 is configured as a high-pass filter or a band-pass filter, and its set value is about 0.2 Hz for a high-pass filter and about 0.2 to 30 Hz for a band-pass filter. Good. Depending on the part to be measured, vibration accompanying respiration is further added.
The cutoff frequency may be around Hz. When respiration is desired to be detected, a band pass filter of about 0.2 to 1 Hz may be used. If this respiration detection unit is provided at the same time, respiration can be detected and the influence of respiration on pulse measurement can be removed. It will be easier.

However, in this pulse detecting device,
If the vibration sensor 2 is brought into contact with the skin 10 of the living body and the bone vibration of the living body is picked up by the vibration sensor 2, the pulse (heartbeat) waveform included in the bone vibration can be extracted in the discrimination circuit 4. By processing the output, the pulse rate can be measured, and the excited state of the living body can be known. The vibration sensor 2 may be brought into contact with the skin 10 of any part of the living body as long as it can pick up the bone vibration of the living body, and the part where the skin is exposed in the clothing state is like an earlobe. Except for a part, it is a part where the bone vibration can be clearly picked up, so that the part to be measured is practically not selected.

However, muscles and fats interposed between the bone 11 and the skin 10 attenuate the bone vibration transmitted to the vibration sensor 2 brought into contact with the skin 10 or change the frequency characteristics. It is preferable to measure the bone vibration at a part where the muscle and fat are small, for example, as shown in FIG. 4, at a head, a neck, and a wrist, and at a part where vibration derived from a pulse (heartbeat) during the bone vibration is large. It is preferable to measure near a certain heart. When measurement is performed at these sites, the detection sensitivity is increased and the original waveform can be reliably picked up. The head, neck, and wrist are also places where the living body has experience attaching something other than the vibration sensor 2, and therefore, there is also an advantage that the vibration sensor 2 can be mounted without discomfort.

When measuring at the head, the forehead is particularly preferred. The portion with the hair has insufficient contact of the vibration sensor 2, and the portion below the forehead has a large curved surface and a lot of muscle and fat, while the forehead has a small amount of muscle and fat and a large area with a small curvature. The reason for this is that the detection sensitivity is increased and the difference in the contact point of the vibration sensor 2 is less likely to appear as a large difference in the detection sensitivity. In particular, when the above-mentioned optical fiber 20 is mainly used as the vibration sensor 2, the vibration sensor 2 can be attached to the forehead like a headband as shown in FIG. Further, in the case of detecting bone vibration in the neck or wrist, when using a vibration sensor 2 mainly composed of the optical fiber 20, as shown in FIGS. 5 and 6, the vibration sensor 2 is configured in a necklace style or a bracelet style. Good to do. 5 is a block provided with a discrimination circuit 4 and a display unit, and is suspended from the vibration sensor 2 in a necklace-like manner.

FIGS. 2A and 2B show examples of bone vibration signals input to the discrimination circuit 4. FIG. 2A shows a signal measured at the forehead, FIG. 2B shows a signal measured at the wrist, and FIG. c) shows the measurement at the neck, and (d) shows the measurement at the buttocks. All are measured in a resting state, but the pulse (heart rate)
The vibration caused by the above is very clearly apparent, which indicates that the discrimination process in the discrimination circuit 4 is easy. In addition, when the measurement is performed on a skeleton such as the buttocks, it can be seen that the influence of respiration is also detected as shown in FIG.

FIGS. 7 to 10 show specific examples of the structure of the vibration sensor 2 in the case where bone vibration is detected at the forehead by the vibration sensor 2 mainly composed of the optical fiber 20. FIG. FIG. 7 shows the case where the vibration sensor 2 is arranged along the inner surface of the vine 61 of the glasses (sunglasses) 60, FIG. 8 shows the case where the vibration sensor 2 is arranged along the inner surface of the sun visor (hat) 63, and FIG. Shows a vibration sensor 2 arranged along the inner surface of a telescopic headband 65 of a goggle 64 having a liquid crystal display for virtual reality. The vibration sensor 2 may be attached using a double-sided adhesive tape or the like.

FIG. 10 shows the arrangement of the vibration sensor 2 mainly composed of the optical fiber 20 on the inner surface side of a synthetic resin head band 66 having a length adjusting portion 68, in which a flexible material 67 such as a synthetic resin plate is provided. Using the vibration sensor 2 as a backup material for the vibration sensor 2 and attaching the vibration sensor 2 to the flexible
It is fixed to 6. Headband 66 with length adjustment section 68
Tighten the flexible material 67 and the vibration sensor 2
Adheres to the forehead. Note that, in each of the above specific examples, the vibration sensor 2 is mainly described with the optical fiber 20 as described above. However, it is needless to say that the vibration sensor 2 may be composed of a piezoelectric element or the like.

FIGS. 11 to 15 show a specific example in which the vibration sensor 2 composed of a piezoelectric element or the like is provided on the inner surface of the holder 6 such as the headband 66. In FIG. 11, the vibration sensor 2 is housed in a recess 70 provided on the inner surface of the holder 6, and in FIG.
A spring material 71 is arranged between the bottom surface of the first sensor 0 and the vibration sensor 2, and the vibration sensor 2 is pressed against the skin 10 by the spring material 71. Even if the holder 6 is slightly away from the skin 10, the vibration sensor 2 can be reliably brought into contact with the skin 10.

Instead of the spring member 71, a cushioning member 72 such as urethane foam may be provided as shown in FIG.
When the vibration sensor 2 is excessively pressed against the skin 10, bone vibration may be suppressed due to this. However, such a situation can be prevented from occurring, and the touch can be improved. In this case, the cushioning member 72 is preferably larger than the vibration sensor 2 in terms of pressure dispersion and a feeling of fitting to the skin 10. As shown in FIG. 14, if a recess 73 is provided in the cushioning material 72 and the vibration sensor 2 is placed therein, a more favorable fit can be obtained and the vibration sensor 2 can be securely held. As shown in FIG.
It goes without saying that both 1 and the cushioning material 72 may be used in combination. In the figure, reference numeral 73 denotes a plate arranged between the spring member 71 so that the effect of the spring member 71 is not absorbed by the buffer member 72.

By the way, the living body is not completely still even at the time of sleep, and the bone vibration is extremely small, is easily affected by noise, and is especially larger than the bone vibration during the activity. The vibration sensor 2 picks up noise. Therefore, if the output of the vibration sensor 2 is amplified as it is, the pulse may not be detected due to saturation of noise. The block circuit diagram shown in FIG. 16 addresses this point, and the vibration sensor 2
The amplification of the vibration signal, which is the output of the first stage, is performed in two stages. By lowering the gain in the first stage amplifier circuit 30, the output of the amplifier circuit 30 is saturated by noise accompanying the movement of the living body. In the discrimination circuit 4 which is a band-pass filter, the frequency components lower and higher than the pulse and the circuit noise are removed, and the pulse is amplified by the second-stage amplifier circuit 35, so that the pulse detection process is facilitated. And

In the case of directly detecting a low frequency component such as a pulse, the narrower the band of the band-pass filter and the steeper its cutoff characteristic, the more the pulse signal waveform is deformed due to the characteristic of the filter. From a waveform in which each beat can be clearly confirmed, a signal of a certain frequency becomes a repeated waveform in which the amplitude increases or decreases. For this reason, by taking the absolute value of the signal and taking the envelope connecting the absolute value by the envelope circuit 9, the pulse waveform can be extracted without being affected by the movement of the living body.

[0021]

As described above, according to the present invention, the pulse can be detected from the bone vibration of the living body without limiting the measurement site, and the pulse can be detected. Detection can be performed more easily.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of one embodiment.

FIGS. 2A to 2D are time charts each showing an example of bone vibration.

FIG. 3 shows an example of the vibration sensor according to the first embodiment;
Is a longitudinal sectional view, and (b) is a transverse sectional view.

FIG. 4 is an explanatory diagram showing a more preferable portion of the bone vibration detection site according to the first embodiment.

FIG. 5 is an explanatory view showing an example of mounting a vibration sensor.

FIG. 6 is an explanatory view showing another mounting example of the vibration sensor.

FIG. 7 is a perspective view illustrating an example of a vibration sensor and a holder that holds the vibration sensor.

FIG. 8 is a perspective view showing another example of the above.

FIG. 9 is a perspective view showing still another example of the above.

FIG. 10 is a perspective view showing still another example of the above.

FIG. 11 is a sectional view showing another example of the above.

FIG. 12 is a sectional view showing still another example of the above.

FIG. 13 shows another example of the above, in which (a) is a sectional view,
(b) is a sectional view of the cushioning material.

FIG. 14 shows still another example of the above, wherein (a)
Is a sectional view, and (b) is a sectional view of a cushioning material.

FIG. 15 is a sectional view showing still another example of the above.

FIG. 16 is another block circuit diagram of Embodiment 1;

[Explanation of symbols]

 2 Vibration sensor 4 Discrimination circuit 10 Skin 11 Bone

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-31637 (JP, A) JP-A-1-104243 (JP, A) Full-fledged 1986-127702 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) A61B 5/00-5/03

Claims (9)

(57) [Claims] 1. A vibration sensor for detecting bone vibration of a living body
And the electric vibration signal output from this vibration sensor
And a discriminator for discriminating the pulse waveform from the
Pulse detection device. 2. The vibration sensor has a mounting part to a living body.
And one side of the holder that is in contact with the living body.
The pulse detection device according to claim 1, wherein
Place. 3. The holding tool is a stretchable band.
The pulse detection device according to claim 2, wherein 4. A flexible structure is provided between the holder and the vibration sensor.
That there is a backup plate made of wood
The pulse detection device according to claim 2, wherein 5. A spring is provided between the holder and the vibration sensor.
The pulse detection device according to claim 2, wherein the pulse detection device is provided. 6. A cushioning material is provided between the holder and the vibration sensor.
The pulse detecting device according to claim 2, wherein the pulse detecting device is arranged . 7. A recess provided in a cushioning material for a vibration sensor.
7. The pulse detecting device according to claim 6, wherein the pulse detecting device is disposed at a position where the pulse is detected. 8. A band-pass filter comprising: a band-pass filter;
The envelope that derives the envelope waveform of the output waveform of the pass filter
The pulse detecting device according to claim 1, further comprising a wire circuit. 9. The vibration sensor has a flexible optical fiber.
Bar and light emitting element arranged at one end of this optical fiber
And a light receiving element disposed at the other end of the optical fiber.
The pulse detection device according to claim 1, wherein: