JP2002058653A - Detecting unit for organismic signals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting unit for organismic signals, which has a pressure detecting means to detect organismic vibration of a subject and a signal processing means to extract organismic signals such as pulse signals, breath signals, etc., from signals outputted from the pressure detecting means. SOLUTION: This detecting unit for signals is equipped with a hollow tube comprising a flexible and elastic material and a pressure detecting means comprising a micro-differential pressure variation sensor connected to the tube. Pulse signals and breath signals are detected by detecting vital micro-vibration generated by an organism transmitted to the pressure detecting means. That is, when pressure variation of organismic vibration is transmitted to the hollow tube, organismic signals can be detected. Thus organismic signals of a human body can be detected without touching the body by placing a means to detect variation of air pressure in the hollow tube under a bedding or a seat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological signal detecting device for detecting a biological signal such as a heartbeat or a breath without directly attaching a sensor to a human body and without causing discomfort to the human body.

[0002]

2. Description of the Related Art In a medical examination or diagnosis, a method of measuring a biological signal such as a heartbeat or respiration by attaching a detector directly to a patient is usually performed. When the detector is directly attached to the patient's body, a natural measurement result is often not obtained because the patient is psychologically oppressed, and the patient suffers when the detector is worn for a long time. Also, when trying to obtain biological signal information such as the patient's heartbeat or breathing during sleep, the patient must wear the detector all the time while sleeping, which hinders the patient's natural sleep. There is a possibility that the measurement data of the state cannot be obtained. Moreover, it is difficult for patients to make continuous measurements every day, with pain.

On the other hand, if it becomes possible to continuously detect a biological signal such as a heartbeat or breathing of a worker who is performing daily work or a vehicle driver who is driving, if he / she is able to detect daily health condition or sudden physical You will be able to know
It will also generate high utility value in terms of health management and safety. That is, the daily health condition is continuously stored, and if abnormalities or abnormalities are recognized, an instruction to stop the work of the working worker or the vehicle driver or stop the operation of the vehicle is issued. Health management and safety can be ensured.

[0004] As described above, if it is possible to detect a biological signal such as a heartbeat or respiration without imposing a burden on the human body, it is possible for an elderly person to easily grasp the daily health condition, In the facility, the condition of the hospitalized patient can always be grasped, and it is a means to prevent the occurrence of a vehicle accident by immediately knowing the physical abnormality of the driver of the vehicle.

As a method of detecting a biological signal without imposing a burden on the human body, a sensor unit is attached to the body. No. 9-72310. The detection means in this application uses a band to attach a small and light sensor unit to a body such as a wrist, an ankle, a finger, or an arm, and transmits a signal wirelessly to eliminate wiring, thereby reducing a load on the body. It is alleviating. Japanese Patent Application Laid-Open No. 7-88092 proposes a method of measuring a heart rate by irradiating light to the body and detecting reflected light or transmitted light thereof. Can be done with

[0006]

However, according to the method proposed in Japanese Patent Application Laid-Open No. 9-72310, the detection means is attached to the body even though it is small, and the problem is caused by the extra wearing. Pleasure is not eliminated, and hinders sleep, especially during bedtime. On the other hand,
The method proposed in -88092 eliminates the need to attach a detecting means to the body, but there is a problem that if light is irradiated during sleep, the sleep may be disturbed, and the cost is further increased.

[0007] In view of the above problems, the present invention can detect a biological signal such as a heartbeat or a respiration without directly attaching an instrument such as a detector to the human body, and can manufacture the biological signal at a low cost. It is an object to provide a signal detection device.

[0008]

A first aspect of the present invention is a pressure detecting means for detecting a biological vibration of a subject, and a signal processing means for extracting a biological signal such as a heartbeat signal or a respiratory signal from an output signal of the pressure detecting means. Wherein the pressure detecting means comprises a hollow tube made of a material having flexibility and elasticity, and a slight differential pressure sensor connected to the tube. .

According to a second aspect of the present invention, there is provided the biological signal measuring device according to the first aspect, wherein the minute differential pressure sensor is a low-frequency condenser microphone.

A third invention is the biological signal measuring device according to the first invention, wherein a flexible core is inserted into a hollow portion of the tube.

A fourth aspect of the present invention is the biological signal measuring apparatus according to the first aspect, wherein the biological signal is detected in a state in which the tube end on the side to which the slight differential pressure sensor is not connected is opened. I do.

A fifth aspect of the present invention is the biological signal measuring apparatus according to the first aspect, wherein the biological signal is detected in a state in which a tube end on a side to which the micro differential pressure sensor is not connected is closed. I do.

[0013]

The biological signal measuring device of the present invention comprises a hollow tube made of a material having flexibility and elasticity, and a pressure change detecting means comprising a small differential pressure change sensor connected to the tube. By detecting minute biological vibrations generated by the living body transmitted to the pressure detecting means, a heartbeat signal and a respiratory signal are detected. That is, if the pressure change of the biological vibration is transmitted to the hollow tube, the biological signal can be detected. Therefore, by arranging means for detecting a change in air pressure in the hollow tube below the bedding or under the seat to be seated, it is possible to detect a biological signal of the human body without contacting the human body.

Further, since a low-frequency condenser microphone is used as the differential pressure sensor, a minute pressure change in a low-frequency region can be reliably detected. The response speed of the pressure detecting means using a hollow tube can be appropriately adjusted by inserting a core wire into the hollow portion of the tube and adjusting the volume of the hollow portion.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an outline of a biological signal detecting apparatus according to the present embodiment. FIG. 2 shows a pressure detecting means in a sectional view. FIG. 3 shows a sectional view of the pressure detecting means in the second embodiment. FIG. 4 shows a structural diagram of a condenser microphone used for pressure detecting means, and FIG. 5 shows a graph of an output result.

The pressure detecting means 11 comprises a slight differential pressure sensor 12 and a pressure detecting tube 13, and is arranged on a bed 19. As shown in FIG. 1, the range on the bedding where pressure can be detected by bending the tube several times is widened.

As shown in FIG. 2, the pressure detecting tube 13 is disposed on a hard sheet 22 laid on a bed, on which an elastic cushion sheet 21 and bedding (futon) 20 are laid. The subject lies on the bedding 20.

The fine differential pressure sensor 12 is a sensor for detecting a minute pressure fluctuation. In this embodiment, the low-frequency condenser microphone 30 is used. However, the present invention is not limited to this. What is necessary is just to have a range.

As shown in FIG. 4, a low-frequency condenser microphone 30 used as the micro differential pressure sensor 12 in this embodiment has an opening 31 at one end, and has a closed end at the other end. A casing 39 formed in a cylindrical shape, and a screen 3 which is a pressure receiving surface disposed in order in a direction away from the opening 31 in the casing 39, that is, in a direction toward the back.
2, an opposing electrode 33 provided opposite to the screen 32 and parallel to the screen 32, and an amplifier circuit 34 having an FET transistor and the like and one lead terminal connected to the opposing electrode 33, At the rear end of the casing 39, that is, at the end of the closed casing 39 opposite to the opening 31,
A rear chamber 37 formed by a partition wall 35 having a through hole 36 is provided. A curtain 38 is provided outside the casing 39 so as to face the opening 31.

The operation of the low-frequency condenser microphone 30 will be described. When vibration is generated in the outside air, the low-frequency condenser microphone 30 transmits the vibration to the inside of the casing 39 through the opening 31 so that the screen (pressure receiving surface) 32 bends and deforms. The distance fluctuates minutely, and its capacitance changes. This change in capacitance is detected by the amplifier circuit 34,
By amplifying and outputting a detection signal, a minute pressure fluctuation is detected. The low-frequency condenser microphone 30 is provided with a rear chamber 37, unlike a general acoustic microphone. When the volume of the rear chamber 37 is changed, the frequency characteristic of the detected pressure fluctuation changes. In the low-frequency condenser microphone 30 used in this embodiment, the volume of the rear chamber 37 is adjusted so that the sensitivity in the low-frequency region is increased. In addition, curtain 3
Numeral 8 is provided to control the influence of external wind and the like.

The low-frequency condenser microphone 30 used in this embodiment is replaced with a general acoustic microphone which is not considered for the low-frequency region, and is provided with a chamber behind the pressure-receiving surface to provide a low-frequency condenser microphone. The characteristics are greatly improved, and are suitable for detecting minute pressure fluctuations in the pressure detection tube. In addition, it is excellent for measuring pressure with a small difference, and 0.2 Pa
And a dynamic range of about 50 Pa, and has several times the performance of a micro differential pressure sensor using a commonly used ceramic. This is suitable for detecting a minute pressure applied to the. The frequency characteristic is 0.1
It shows a substantially flat output value between 10 Hz and 10 Hz, and is suitable for detecting biological signals such as heart rate and respiratory rate.

The pressure detecting tube 13 has an appropriate elasticity so that the internal pressure fluctuates according to the pressure fluctuation range of the biological signal. Further, in order to transmit the pressure change to the micro differential pressure sensor 12 at an appropriate response speed, it is necessary to appropriately select the volume of the hollow portion of the tube. When the pressure detection tube 13 cannot satisfy both the appropriate elasticity and the hollow volume at the same time, it is necessary to load the core wire 23 into the hollow portion of the pressure detection tube 13 as shown in FIG. it can. This core wire 23 is desirably formed of a material having elasticity.

On the other hand, it has been found from experiments that the frequency characteristics to be detected differ depending on the treatment of the end of the pressure detecting tube 13. When the end B of the pressure detection tube 13 (the end opposite to the side to which the fine differential pressure sensor 12 is connected) is opened, a frequency component of 1 Hz or less is difficult to be detected. It is difficult to detect a frequency component of 1 Hz or more.

The heartbeat signal contains many frequency components of 1 Hz to 10 Hz, while the respiration signal contains 0.1 to 10 Hz.
Many frequency components of 0.5 Hz are included. Therefore, when detecting a heartbeat signal, the filter 15 is set to 5 Hz to 10 Hz.
By setting the frequency to Hz and opening the end portion B of the pressure detection tube 13, the effect of eliminating pressure fluctuation due to breathing is further enhanced.

On the other hand, when a respiratory signal is detected, the filter 15 is set at 0.1 to 0.5 Hz, and the end B of the pressure detection tube 13 is closed to eliminate pressure fluctuation due to heartbeat.

FIG. 5 shows the result of detecting a heartbeat signal and a respiratory signal using the biological signal detecting device 10 of the present embodiment under the above conditions.

The data of the biological vibration detected by the pressure detecting means 11 is converted into a predetermined range of frequency components through a filter 15 of a control device 14, then digitized by an A / D converter 16 and sent to a data processing unit 17.

The data processing unit stores and saves the continuously transmitted data, analyzes the health condition of the subject from these data, and issues a warning if an abnormality or abnormality occurs. In addition, the data and analysis results of these biological signals are displayed on the display device 18 so that the state of change of the biological signals can be observed.

FIG. 5 is a graph showing the results of detection of a heartbeat signal and a respiration signal by the biological signal measuring device 10 of the present embodiment. FIG. 5A shows the output result when the end B of the pressure detection tube 13 is closed. (B) shows the output result of only the heartbeat signal when the end B of the pressure detection tube 13 is opened. The heartbeat signal waveform shows that the output result of FIG. 5B has better output level and S / N, and that it is more appropriate to open the end B of the pressure detection tube 13 for measurement of the heartbeat signal. ing.

In this embodiment, an example is described in which only one pressure detecting means 11 is connected to the control device. However, a plurality of pressure detecting means 11 may be connected and simultaneously detect a plurality of biological signals such as a heartbeat signal and a respiratory signal. Good.

In this embodiment, a case has been described in which the biological signal of a subject lying down is measured. However, in the case of a worker working in a sitting posture or a vehicle driver, this pressure detecting means is arranged on a seat that is seated. Thereby, the biological signal of the subject can be detected.

[0031]

According to the biological signal detecting apparatus of the present invention, it is not necessary to directly attach a detector for detecting a biological signal such as a heartbeat signal or a respiratory signal to the subject's body, so that the subject suffers or feels discomfort. Without this, it is possible to continuously detect the biological signal.

Therefore, it is possible to continuously monitor the health condition of the patient during sleep, the daily health condition of the elderly, or sudden changes in the physical condition of the driver. A great effect can be expected in terms of aspect.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a biological signal detection device according to an embodiment.

FIG. 2 is a cross-sectional view showing an arrangement state of a pressure detecting unit as viewed from a direction of an arrow in FIG.

FIG. 3 is a cross-sectional view showing a state where a core wire is loaded on a pressure detecting means.

FIG. 4 is an explanatory diagram illustrating a structure of a condenser microphone used for pressure detection means.

FIG. 5 is a graph showing an output result.

[Explanation of symbols]

 Reference Signs List 10 biological signal detecting device 11 pressure detecting means 12 slight differential pressure sensor 13 pressure detecting tube 14 control device 15 frequency filter 16 A / D converter 17 data processing unit 18 display device 19 bed 20 bedding 21 cushion sheet 22 hard sheet 23 core material REFERENCE SIGNS LIST 30 low frequency condenser microphone 31 opening 32 screen 33 counter electrode 34 amplifier circuit 35 partition wall 36 through hole 37 chamber 38 curtain 39 casing

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[Procedure amendment]

[Submission date] November 1, 2000 (200.11.
1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

Claims (5)

[Claims] 1. A biological signal measuring apparatus comprising: pressure detecting means for detecting a biological vibration of a subject; and signal processing means for extracting a biological signal such as a heartbeat signal or a respiratory signal from an output signal of the pressure detecting means. A biological signal detecting device, wherein the pressure detecting means comprises a hollow tube made of a material having flexibility and elasticity, and a micro differential pressure sensor connected to the tube. 2. The biological signal detecting device according to claim 1, wherein the minute differential pressure sensor is a low-frequency condenser microphone. 3. The biological signal detecting device according to claim 1, wherein a flexible core wire is inserted into a hollow portion of the tube. 4. The biological signal detection device according to claim 1, wherein the biological signal is detected in a state where the tube end on the side to which the micro differential pressure sensor is not connected is opened. 5. The biological signal detection device according to claim 1, wherein the biological signal is detected in a state where the tube end on the side to which the micro differential pressure sensor is not connected is closed.