JP2017023595A - Bioacoustic stethoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimally suppress external noise in a biological sound acquisition apparatus.SOLUTION: A bioacoustic stethoscope apparatus (200) includes: a biological sound acquisition part (100) for acquiring biological sound; a body part (11); and a damper part (13) retaining the biological sound acquisition part to the body part so as to prevent the biological sound acquisition part from coming into contact with the body part. The biological sound acquisition part includes: a sensor part (21) for acquiring the biological sound; a hollow case (110) for storing the sensor part; and a diaphragm (120) retaining the sensor part in the case so as to prevent the sensor part from coming into contact with the case.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technical field of a biological sound auscultation apparatus such as an electronic stethoscope.

  In this type of device, a sensor such as a microphone is disposed inside the housing. When body sounds are collected by this type of apparatus, the housing is brought into contact with the body surface of the subject. The sound collected by this type of device includes external noise in addition to body sounds. For this reason, this type of device can suppress external noise.

  For example, Patent Document 1 discloses that a sound collecting unit constituting member having a concave portion that forms a sealed space when a sound is collected on a part that contacts the body surface of the housing on the side opposite to the surface that contacts the body surface; And a holding member in contact with the outer periphery of the component constituting member, and a technique for suppressing external noise by making the acoustic impedance of each of the sound collecting constituting member and the holding member satisfy a predetermined condition is disclosed.

  Or in patent document 2, while arrange | positioning a microphone in the space partitioned by the plate-shaped biological sound propagation part which makes the surface closely_contact | adhere to the body surface of a subject, and a housing, rather than a biological sound propagation part There is disclosed a technique for suppressing mixing of external environmental noise and sliding noise by filling a material with low Shore A hardness into the space and embedding a microphone.

JP 2012-152377 A JP2013-074915A

  The background art described above has a technical problem that external noise is not sufficiently suppressed.

  This invention is made | formed in view of the said problem, for example, and makes it a subject to provide the biological sound auscultation apparatus which can suppress an external noise suitably.

  In order to solve the above problems, the body sound auscultation apparatus of the present invention is configured so that the body sound acquisition unit that acquires body sound, the body unit, and the body sound acquisition unit do not contact the body unit. A damper unit that holds the biological sound acquisition unit, wherein the biological sound acquisition unit is a sensor unit that acquires the biological sound, a hollow case that houses the sensor unit, and the sensor unit is the case And a diaphragm for holding the sensor portion on the case.

  The effect | action and other gain of this invention are clarified from the form for implementing demonstrated below.

It is a block diagram which shows the structure of the electronic stethoscope which concerns on an Example. It is sectional drawing which shows the structure of the principal part of the electronic stethoscope which concerns on an Example. It is sectional drawing which shows the structure of the principal part of the electronic stethoscope which concerns on a comparative example. It is a figure for demonstrating the noise suppression effect of the electronic stethoscope which concerns on an Example. It is a figure for demonstrating the other effect of the damper part of the electronic stethoscope which concerns on an Example. It is a figure which shows an example of the external noise interruption | blocking characteristic of a diaphragm. It is a figure which shows the 1st modification of the electronic stethoscope which concerns on an Example. It is a figure which shows the 2nd modification of the electronic stethoscope which concerns on an Example. It is a figure which shows the 3rd modification of the electronic stethoscope which concerns on an Example. It is a figure which shows the 4th modification of the electronic stethoscope which concerns on an Example.

  An embodiment according to the biological sound auscultation apparatus of the present invention will be described.

  The biological sound auscultation apparatus according to the embodiment includes a biological sound acquisition unit, a main body unit, and a damper unit that holds the biological sound acquisition unit in the main body unit so that the biological sound acquisition unit does not contact the main body unit. , And is configured.

  The biological sound acquisition unit includes a sensor unit that acquires a biological sound, a hollow case that houses the sensor unit, and a diaphragm that holds the sensor unit in the case so that the sensor unit does not contact the case; It is configured with.

  When this type of device is used for auscultation, for example, biological noise caused by the blood flow of the user who handles the device, touching the device with a user's finger or clothes, or the skin of the subject There is a possibility that contact noise generated by touching the apparatus and biological noise caused by sound other than the target biological sound of the subject are acquired together with the target biological sound.

  In the biological sound auscultation apparatus according to the present embodiment, first, the biological sound acquisition unit is held by the damper unit so that the main body unit and the biological sound acquisition unit do not contact each other. For this reason, it is possible to prevent noise from directly propagating from the main body to the body sound acquisition unit. In addition, even when noise propagates from the main body through the damper unit to the biological sound acquisition unit, the noise is attenuated by the action of the damper unit, so that the propagation of noise to the biological sound acquisition unit is suppressed. Can do.

  Next, the sensor unit is held by the diaphragm so that the case constituting the biological sound acquisition unit and the sensor unit do not contact each other. For this reason, it is possible to prevent noise from directly propagating from the case to the sensor unit. Further, even when noise propagates from the case to the sensor unit through the diaphragm, the noise is attenuated by the action of the diaphragm, so that the propagation of noise to the sensor unit can be suppressed.

  Thus, in the biological sound auscultation apparatus according to the present embodiment, even if noise propagates to the biological sound acquisition unit, the propagation of noise from the case of the biological sound acquisition unit to the sensor unit is suppressed. . That is, in the body sound auscultation apparatus according to the present embodiment, noise propagation to the sensor unit is suppressed in two stages. As a result, according to the biological sound auscultation apparatus according to the present embodiment, external noise can be suitably suppressed.

  In addition, since the biological sound acquisition unit is held by the damper unit, for example, the portion of the biological sound acquisition unit that contacts the body surface of the subject can be brought into close contact with the body surface relatively easily. For this reason, it is possible to reduce a sense of incongruity caused by the device touching the body that the subject receives during auscultation.

  In one aspect of the biological sound auscultation apparatus according to the present embodiment, the case constituting the biological sound acquisition unit has an opening. The diaphragm is connected to the case so as to close the opening of the case. The diaphragm has one surface facing the body surface of the subject and another surface opposite to the one surface. The sensor unit is disposed at a position not in contact with the case on the other surface of the diaphragm.

  According to this aspect, it is possible to suitably acquire a biological sound by the sensor unit, and it is possible to suitably suppress the propagation of noise to the sensor unit.

  In another aspect of the body sound auscultation apparatus according to the present embodiment, the main body part constituting the body sound auscultation apparatus has a hollow housing part that houses the body sound acquisition part. A damper part hold | maintains a biological sound acquisition part in an accommodating part so that a biological sound acquisition part may not contact | connect a main-body part.

  According to this aspect, it is possible to suitably protect the body sound acquisition unit, and it is possible to suitably suppress the propagation of noise to the body sound acquisition unit.

  In another aspect of the biological sound auscultation apparatus according to the present embodiment, the damper portion is configured such that the elastic force of the damper portion is higher than the elastic force of the diaphragm. Since the total elastic force is equal to the elastic energy, the higher the elastic force of the object, the harder the object.

  Here, according to the inventor's research, the following matters have been found. That is, it is desirable that the diaphragm is designed to be as thin as possible in order to appropriately acquire the target biological sound by the sensor unit. On the other hand, in order to hold the sensor part well, the diaphragm is required to have a certain degree of hardness.

  The elastic force is proportional to the Young's modulus (longitudinal elastic modulus) related to the hardness (hardness) and the cube of the thickness. Therefore, the elastic force capable of achieving both proper acquisition of biological sound and good holding of the sensor unit is determined, and the material (hardness) and thickness of the diaphragm are determined so as to achieve the determined elastic force. If selected, it is possible to design a diaphragm that can achieve both appropriate acquisition of body sound and good holding of the sensor part relatively easily.

  Similarly, the damper part is required to be compatible with that the body sound acquisition unit can be relatively easily attached to the body surface of the subject during auscultation and to hold the body sound acquisition part well.

  When the elastic force of the damper portion is higher than the elastic force of the diaphragm, it has been found by the inventor's research that the requirement for the diaphragm and the requirement for the damper portion are satisfied.

  An embodiment according to the biological sound acquisition apparatus of the present invention will be described with reference to the drawings. In this embodiment, an electronic stethoscope is taken as an example of the body sound acquisition device.

(Configuration of electronic stethoscope)
The configuration of the electronic stethoscope according to the embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of an electronic stethoscope according to the embodiment.

  In FIG. 1, an electronic stethoscope 200 includes a signal acquisition unit 21, a bandpass filter 22, a cutoff frequency adjusting unit 23 that adjusts a cutoff frequency related to the bandpass filter 22, a power amplifier 24, and the power amplifier. A volume adjustment unit 25 for adjusting the gain and an earphone 26 are provided. It should be noted that various known modes can be applied to the signal acquisition unit 21 and the like, and a detailed description thereof will be omitted.

(Structure of the listening part)
Next, the structure of the listening part of the electronic stethoscope 200 will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating a structure of a main part of the electronic stethoscope according to the embodiment.

  In FIG. 2, the listening unit includes a main body unit 11, a damper unit 13, and a sensor module 100. Here, the “sensor module 100” according to the embodiment is an example of the “body sound acquisition unit” according to the present invention.

  The sensor module 100 includes a signal acquisition unit 21, a case 110, and a diaphragm 120 that holds the signal acquisition unit 21 in the case 110 as an example of the “sensor unit” according to the present invention. The sensor module 100 may include, for example, a bandpass filter 22 (see FIG. 1) in addition to the signal acquisition unit 21.

  An opening is formed on the side of the case 110 facing the body surface of the person to be measured (subject) (the lower side in FIG. 2). The diaphragm 120 is connected to the case 110 so as to close the opening. The signal acquisition unit 21 is disposed in a space 130 formed by the case 110 and the diaphragm 120.

  More specifically, the signal acquisition unit 21 is on the surface (upper surface in FIG. 2) opposite to the surface (the lower surface in FIG. 2) of the diaphragm 120 facing the body surface of the measurement subject. These are arranged at positions not in contact with the case 110.

  The main body 11 has a hollow housing portion 12 that houses the sensor module 100. The damper portion 13 holds the sensor module 100 in the housing portion 12 so that the sensor module 100 does not contact the main body portion 11.

(Comparative example)
Here, the structure of the listening part of the electronic stethoscope 500 according to the comparative example will be described with reference to FIG. FIG. 3 is a cross-sectional view showing the structure of the main part of an electronic stethoscope according to a comparative example.

  In FIG. 3, the electronic stethoscope 500 includes a main body 510 and a sensor 520. Here, in particular, the sensor unit 520 is embedded in the main body 510 so that a part of the sensor unit 520 is exposed.

  By the way, at the time of auscultation, for example, biological noise caused by a blood flow of a measurer who handles the electronic stethoscope 500, and contact noise due to a measurer's finger or clothes touching the main body 510 are measured noise. Propagate to the sensor unit 520. In addition, biological noise caused by sound other than the target biological sound (for example, breathing sound) of the measurement subject and contact noise caused by the body 510 etc. touching the measurement subject's skin or the like are measured subject. It propagates to the sensor unit 520 as noise. In particular, since the electronic stethoscope 500 is not provided with a configuration that attenuates the noise, the noise may interfere with auscultation.

  In addition, during auscultation, when the sensor unit 520 is tilted due to, for example, the way the measurement person holds or due to the shape of the body surface of the measurement subject, for example, a portion indicated by a broken line circle C1 or a broken line circle C2 There is a possibility that the location indicated by or the like does not contact the body surface of the person being measured and cannot be properly auscultated. Alternatively, when the sensor unit 520 is pressed relatively strongly against the measurement subject, the measurement subject may feel uncomfortable.

(Effect of the present invention)
In the electronic stethoscope 200 according to the present embodiment, as shown in FIG. 2, the sensor module 100 is held by the damper portion 13 so that the main body portion 11 and the sensor module 100 do not contact each other (so-called sensor module). 100 is floating from the main body 11). For this reason, it is possible to prevent noise from directly propagating from the main body 11 to the sensor module 100. Further, as shown in FIG. 4, even when noise propagates from the main body portion 11 to the sensor module 100 via the damper portion 13, the noise is attenuated by the action of the damper portion 13. Noise propagation to the can be suppressed.

  Further, the signal acquisition unit 21 is held by the diaphragm 120 so that the case 110 of the sensor module 100 and the signal acquisition unit 21 do not come into contact (so-called signal acquisition unit 21 is floating from the case 110) ( (See FIG. 2). For this reason, it is possible to prevent noise from directly propagating from the case 110 to the signal acquisition unit 21. Further, even when noise propagates from the case 110 through the diaphragm 120 to the signal acquisition unit 21, the noise is attenuated by the action of the diaphragm 120, so that noise propagation to the signal acquisition unit 21 is suppressed. be able to.

  Therefore, according to the electronic stethoscope 200 according to the present embodiment, the noise in the signal acquisition unit 21 can be suitably reduced, thereby enabling good auscultation.

  Further, the sensor module 100 has a certain range of movement by being held by the damper portion 13. For this reason, at the time of auscultation, as shown in FIG. 5, for example, even if the main body 11 is inclined with respect to the body surface of the person to be measured, the diaphragm 120 of the sensor module 100 is appropriately placed on the body surface of the person to be measured. It can be adhered. As a result, it is possible to prevent variation in measurement due to how the electronic stethoscope 200 is applied to the measurement subject.

(Diaphragm characteristics)
Next, the external noise blocking characteristics of the diaphragm 120 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of the external noise cutoff characteristic of the diaphragm. FIG. 6 is constructed based on the result obtained by measuring the vibration transmitted to the diaphragm 120 by the signal acquisition unit 21 when vibration is applied to the sensor module 100 using a vibration exciter.

  In each graph of FIG. 6, a diaphragm made of silicone (hardness 50, thickness 0.75 mm), a diaphragm made of silicone (hardness 40, thickness 0.5 mm), and a diaphragm made of ABS resin are used as the diaphragm 120. The measurement result is shown. In FIG. 6, the vibration when a sine wave of 40 Hz and 2 Vp-p is input to the vibrator is 0 dB.

  In FIG. 6, a peak appearing in the vicinity of a frequency of 100 Hz to 200 Hz represents a resonance frequency of an elastic body composed of the diaphragm 120 and the signal acquisition unit 21. Here, the mass of the signal acquisition unit 21 is constant, and as can be seen from FIG. 6, the resonance frequency band moves to the lower frequency side as the material of the diaphragm 120 becomes softer. Further, it can be seen that the softer the material of the diaphragm 120, the more the noise in the high frequency band can be reduced.

  In addition, the frequency of the body sound which an electronic stethoscope makes a measuring object is 50Hz-2000Hz. When considering only the noise reduction effect, it can be said that the diaphragm 120 is more preferably silicone (hardness 40, thickness 0.5 mm).

  However, the diaphragm 120 is required to have the following points in addition to the noise reduction effect. That is, it is desirable that the diaphragm 120 be designed to be as thin as possible in order to appropriately acquire the target biological sound by the signal acquisition unit 21. In addition, the diaphragm 120 is required to have a certain degree of hardness so as not to be loosened by the signal acquisition unit 21.

  In view of the above requirements, it has been found that silicone (hardness 50, thickness 0.75 mm) is more suitable for diaphragm 120 under the research conditions of the inventors.

(Damper part)
Regarding the damper unit 13, in addition to the noise reduction effect, the sensor module 100 can be brought into close contact with the body surface of the measurement subject relatively easily during auscultation and the effect of reducing the load on the measurement subject (patient). Is required. Of course, the damper unit 13 supports the total mass of the signal acquisition unit 21, the diaphragm 120 and the case 110, that is, the entire sensor module 100. In addition, the damper unit 13 performs all of the above-described effects including the noise reduction effect. It is required to bring.

  In consideration of the above requirements, it has been found that silicone (hardness 30, thickness 2.5 mm) is more suitable for the damper portion 13 under the research conditions of the present inventors.

Here, when attention is paid to the hardness and thickness of the material constituting each of the damper portion 13 and the diaphragm 120, the coefficient k proportional to the elastic force can be expressed as k = Et ³ / R ² . The variable E is the Young's modulus related to hardness, the variable t is the thickness, and R is the radius. The radius of the damper portion 13 according to the present embodiment is, for example, 16 mm, and the radius of the diaphragm 120 is, for example, 10 mm.

  From the above equation, the coefficient k related to the damper portion 13 is about 0.33, and the coefficient k related to the diaphragm 120 is about 0.06. That is, the elastic force of the damper portion 13 is higher than the elastic force of the diaphragm 120.

<First Modification>
As shown in FIG. 7, the side of the sensor module 100 facing the body surface of the person to be measured may be covered with a cap 30.

  If comprised in this way, the adhesion of the stain | pollution | contamination to the sensor module 100 or the damper part 13 can be prevented. In addition, disinfecting the cap 30 every time it is used or used can be relatively easy and hygienic.

  In addition, by using a relatively soft material for the cap 30 and forming the cap 30 to be relatively thin, noise propagating from the main body 11 to the sensor module 100 via the cap 30 can be suppressed and It is possible to eliminate the influence on the acquisition of the body sound.

<Second Modification>
As shown in FIG. 8, a damper portion 13 a having a bellows structure may be used instead of the damper portion 13.

  If comprised in this way, a metal etc. can be used for the damper part 13a, producing the effect of this invention mentioned above, for example, and the freedom degree of material selection can be improved. When the damper part 13a is formed of metal, it is possible to improve shielding properties such as electromagnetic waves, and to suppress the influence of electronic noise on the electronic stethoscope 200.

<Third Modification>
As shown in FIG. 9, a diaphragm 121 having a bellows structure may be used instead of the diaphragm 120.

  If comprised in this way, a metal etc. can be used for the diaphragm 121, producing the effect of the above-mentioned this invention, and the freedom degree of material selection can be improved. When the diaphragm 121 is made of metal, the influence of electronic noise on the electronic stethoscope 200 can be suppressed.

<Fourth Modification>
As shown in FIG. 10, a damper portion 13 a having a bellows structure may be used instead of the damper portion 13, and a diaphragm 121 having a bellows structure may be used instead of the diaphragm 120.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The apparatus is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 11 ... Main-body part, 13, 13a ... Damper part, 21 ... Signal acquisition part, 100 ... Sensor module, 110 ... Case, 120, 121 ... Diaphragm, 200 ... Electronic stethoscope

Claims (4)

A biological sound acquisition unit for acquiring a biological sound;
The main body,
A damper unit that holds the biological sound acquisition unit in the main body so that the biological sound acquisition unit does not contact the main body;
With
The biological sound acquisition unit
A sensor unit for acquiring the biological sound;
A hollow case for housing the sensor unit;
A diaphragm for holding the sensor unit in the case so that the sensor unit does not contact the case;
A body sound auscultation apparatus comprising: The case has an opening;
The diaphragm is connected to the case so as to close the opening;
The diaphragm has one surface facing the body surface of the subject and another surface opposite to the one surface,
The biological sound auscultation apparatus according to claim 1, wherein the sensor unit is disposed at a position that does not contact the case on the other surface. The main body has a hollow housing for housing the biological sound acquisition unit,
The biological sound auscultation apparatus according to claim 1, wherein the damper unit holds the biological sound acquisition unit in the housing unit such that the biological sound acquisition unit does not contact the main body unit. .   The biological sound auscultation apparatus according to any one of claims 1 to 3, wherein an elastic force of the damper portion is higher than an elastic force of the diaphragm.

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