JPH0565176B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a device for non-contact detection of information based on the movement of a living body. The present invention relates to a device for non-contact detecting biological information of a person who is sitting on a chair or who is sitting on a chair and leaning on the backrest.

[Prior art] In order to monitor patients in critical conditions in hospitals, etc., multiple electrodes are attached to the patient's arms and legs to measure the electrocardiogram, and detectors are attached under the nose and chest. Detection of breathing is being carried out. In particular, it is necessary to reliably monitor various biological information day and night for patients whose life or death is at stake. However, wearing the electrodes and detection devices is extremely troublesome for the patient, and may disturb the patient's sleep or make the patient nervous, interfering with treatment.

In addition, in view of these problems, in order to detect the patient's biological information without contact, we have published Japanese Patent Application Laid-Open No. 49-65092.
There is also a device that uses a capacitance sput as a pad placed under the living body, and the capacitance of the capacitance sput changes as the living body moves. The structure is such that the movement of the living body is detected by directly measuring the change in capacitance of the capacitance spot.

However, the change in capacitance due to the movement of a living body is very small, and it is extremely difficult to directly detect this change in capacitance. Therefore, in order to facilitate detection, the entire capacitance spout must be made of a plate-shaped electrode, and a high voltage must also be applied between the electrodes of the capacitance spout. Moreover, it directly applied power with a large current capacity.

Therefore, it is inconvenient to handle, and a complicated configuration for detecting capacitance changes is unavoidable.
It was complicated and expensive. Furthermore, special configurations to prevent electric shock to living bodies were unavoidable. Particularly when using the product on young children or bedridden elderly people, it is essential to take precautions against bedwetting and spilled food.If these measures are not sufficient or if deterioration occurs, serious consequences may occur. This was especially problematic as it could have led to a situation where the

Furthermore, since a change in capacitance is detected as a change in power, even a small amount of noise component present in the detection section results in a measurement error, and there is a high possibility of erroneous detection.

The present invention was created in view of these problems in the prior art, and it detects the breathing of a patient lying on a bed or futon, or sitting on a chair, without any detectors or electrodes attached to the body. It is an object of the present invention to provide a device capable of detecting heart movement, heart movement, and body movement with a simple and safe configuration.

[Means for Solving the Problems] FIG. 1 is a diagram showing the principle of the present invention, and as shown in the figure, the present invention detects body movements 3 of a living body 2 lying on a bed 1. 2, and an electrode 5 for forming a capacitance 7.

Moreover, since body movements of the living body 2 are detected by measuring the oscillation frequency of a variable frequency oscillator whose oscillation frequency changes in response to changes in the capacitance between the electrodes, it is necessary to supply high-capacity power between the electrodes. Changes in capacitance can be detected with a simple configuration.

[Operation] A change in capacitance occurs between the electrodes 4 and 5 due to the body movement 3 of the living body 2, and biological information is obtained by detecting and recording this change.

[Embodiment] FIG. 2 is a circuit diagram of an embodiment of the present invention,
An electrode 11 is connected to the hot line side of the resonant circuit 9 constituting the variable frequency oscillator 8, and an electrode 10 is connected to the earth line side. Although the electrodes 10 and 11 are perpendicular to each other in the figure, they may intersect at any angle.
Further, although the electrodes are shown as lines in the drawings, they may be in the form of strips. However, in order to obtain good detection characteristics, electrode 1
It is desirable that the electrodes 0 and 11 be perpendicular to each other.

FIG. 3 shows another embodiment of the present invention, in which the FET
The electrodes shown in FIG. 2 10 and 11 are connected between the terminal 17 and the ground line 18 of the pierce-type oscillation circuit 12 constructed using the crystal oscillator 19, respectively. It is configured to detect the change in oscillation frequency due to the capacitance, and after extracting the envelope of the frequency change based on the change in the living body by the detector 13, the filter 1
In step 4, unnecessary frequency signals such as noise are removed and recorded on the recording device 15. Although not shown, an appropriate amplification circuit may be provided depending on the signal level, and the recording device 15 may be provided with a device that generates an alarm when the movement of the living body stops.

FIG. 4 shows an example in which a phase shift circuit A and a phase detector 22 are used in place of the oscillation circuit 12 and the detection/detector 13 shown in FIG.
A reference signal is supplied from the signal source 20 to the tuning circuit of the and coil 25 via the resistor 23 (a coil or a capacitor may be used instead of the resistor, or a combination thereof including a resistor). There is. The phase detector 22 detects a phase shift that occurs between the terminals of the resistor 23 due to a change in capacitance in the detection electrodes connected to the terminals 21 and 22. The detection signal is supplied to a recording device 15 via a filter 14 similar to that shown in FIG. 5 and 6 are variations of the phase shift circuit A, in which the terminals 30, 3 connected to the capacitor 26 are shown in FIG.
An electrode is connected between the terminals 32 and 33 connected to the coil 27 to detect a change in phase between the resistor 23 and the terminal 34. In the case shown in FIG. The resistor 23 and the terminal 35 are connected to each other to detect a change in phase between the resistor 23 and the terminal 35.

FIG. 7 is a diagram of measured waveforms in an apparatus embodying the present invention using a method of changing the oscillation frequency of an oscillation circuit configured using a crystal resonator shown in FIG. 3, and is a respiration detection waveform using a thermistor. The electrocardiogram is shown as a, the electrocardiogram is shown as b, and the output waveform of the device according to the present invention is shown as c, in correspondence with each other. In the figure, A shows an example of the waveform in the supine position, B shows an example of the waveform in the prone position, and C shows an example of the waveform in the lateral position. As can be understood from these waveform diagrams, the output waveform of the device according to the present invention approximates a superposition of a respiration detection waveform and an electrocardiogram, and information on both respiration and heartbeat can be obtained. Detection is possible regardless of the sleeping position.

FIG. 8 shows an electrocardiogram (a) experimentally measured while holding breathing and an output waveform diagram c of the device of the present invention, which is a waveform c synchronized with the electrocardiogram (a) in each body position A to C.
is shown to be obtained.

As described above, according to this embodiment, it is possible to obtain reliable biological information without contact, but it is possible to distinguish the output waveform by separating the output waveform into breathing and heartbeat and displaying them separately. Better information is provided for. Note that since the device according to this embodiment is configured to have very high sensitivity, the amplification circuit may become saturated when the patient moves his or her body. Since the amplifier circuit handles very low frequencies and has a large coupling capacity, once it is saturated, it will not be possible to obtain a normal output for a while. In order to prevent this, it goes without saying that an instrument switch, which is well known in the field of medical electronic equipment, is provided in the amplifier circuit so as to automatically discharge the charge that has been charged at the time of saturation.

[Effects of the Invention] As described above, according to the present invention, the breathing and body movements of a patient lying on a bed or futon can be detected without attaching any detector or electrode to the body, and By attaching it to the back of a chair, etc., it can be used as a device to quantitatively assess a patient's condition.It has a very important effect in the medical industry, is great news for doctors and patients, and has an extremely large social impact. .

In addition, since body movements of the living body are detected by measuring the oscillation frequency of a variable frequency oscillator whose oscillation frequency changes in response to changes in the capacitance between the electrodes, there is no need to supply high-capacity power between the electrodes. Therefore, changes in capacitance can be detected with a simple configuration, and the high safety that is particularly required for this type of device can be achieved.

Furthermore, even if there is noise on the connecting wires, etc., the effect can be minimized without the need to apply high voltage, since the system does not detect changes in capacitance due to changes in voltage, etc. , a biological information detection device that can easily remove unnecessary components with a simple configuration such as a filter, and can detect highly reliable biological motion can be provided.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of the present invention, Fig. 2 is a circuit diagram of one embodiment of the invention, Fig. 3 is a partial block circuit diagram of another embodiment of the invention, and Fig. 4 is a further embodiment of the invention. Partial block circuit diagrams of the embodiment of FIGS. 5 and 6
The figure is a circuit diagram of a modified example of the phase shift circuit, and Fig. 7A~
C is a diagram of measured waveforms in an apparatus according to an embodiment of the present invention, and FIGS. 8A to 8C are diagrams of measured waveforms in a state where breathing is held. In the diagram, 1...bed, 2...living body, 4, 5, 1
0, 11... electrode, 12... oscillation circuit, 13...
Detector/detector, 14... filter, 15... recording device.

Claims (1)

[Claims] 1. At least one pair of electrodes for non-contact detection of information based on the movement of a living body as a change in capacitance, and a capacitance formed between one electrode and the living body. , an electrode portion configured to provide a series connection capacitance between the two electrodes and a capacitance formed between another electrode and a living body, the electrode portion being a capacitor component; A living body characterized by comprising: a variable frequency oscillator whose oscillation frequency changes in response to a change in capacitance of a capacitor component; and a filter for extracting the oscillation output of the variable frequency oscillator in a predetermined frequency range. Information detection device. 2. The biological information detection device according to claim 1, wherein one electrode and the other electrode cross each other. 3. The biological information detection device according to claim 1, wherein at least one electrode is formed in a band shape.