JP5467265B2 - Body sound sensor - Google Patents

Description

  The present invention relates to a body conduction sensor that detects sound propagating in a human body or body surface.

  Various sounds such as blood flow sounds, heart sounds, breathing sounds, vibration sounds of meat and bones produced when uttering and exercising, sounds of clothes rubbing against the skin, etc. are transmitted to the human body and body surface (referred to below). These sounds are called body-conducted sounds). In recent years, multiple body-contacting microphones have been proposed to detect human body-conducted sounds. Medical stethoscopes for examining patients and people in noisy places to talk to remote people It is applied to the field of microphones for telephones.

  As a conventional body contact type microphone, for example, as disclosed in Patent Document 1, a condenser microphone element having a diaphragm for detecting sound waves and a body conduction sound are conducted from the skin surface of the human body to the condenser microphone element. There is a body conduction sound microphone with a contact portion. As the material of the contact portion, silicone rubber or the like having an acoustic impedance close to the acoustic impedance of the human soft tissue is used, and high-frequency attenuation due to acoustic impedance mismatching is suppressed. The contact portion is provided by enclosing the entire outer shape of the condenser microphone element with silicone rubber or the like.Furthermore, behind the contact portion, the input body conduction sound is concentrated toward the condenser microphone element. A parabolic metal reflector is provided.

Republished in 2005/067340

  The in-body conduction sound microphone of Patent Document 1 has a structure in which the entire surface of the condenser microphone element is held in an embedded state in an elastic body such as silicone rubber that is a material of the contact portion. When sound wave energy is applied, the entire structure of the microphone element vibrates. Therefore, there is a problem that the energy of sound waves is dispersed and is not efficiently transmitted to the diaphragm, and the sensitivity of body conduction sound detection is lowered. In addition, although a metal reflector is provided, the problem of reducing induction noise or the like has not been considered.

  The present invention has been made in view of the above-described background art, and provides a body conduction sound sensor that has a good body conduction sound detection sensitivity, can effectively reduce the influence of induced noise, and is small and easy to use. The purpose is to do.

  According to the present invention, there is provided a microphone element in which a conversion body for converting sound waves into an electrical signal is exposed, and a through-hole having a bottomed cylindrical shape with an open top and accommodating the microphone element in the center of the bottom. A body sound sensor having a hard material container formed with a circuit board to which the microphone element is fixed, and the circuit board is in a state where the microphone element is accommodated in the through hole. Fixed to the outside of the bottom of the container, the inner space of the container is filled with an elastic polymer material, and the surface of the elastic polymer material exposed from the open end of the container serves as a sound wave input surface. The transducer surface is opposed to the sound wave input surface with the elastic polymer material sandwiched therebetween, and the sound wave input while the sound wave input surface is in contact with the human body surface passes through the elastic polymer material. A Karadashirubeon sensor being transmitted to the body.

  The microphone element is of an electret condenser type, and the circuit board is provided with an amplifying means for amplifying the output of the microphone element.

  The present invention also provides a microphone element provided with an exposed conversion body for converting sound waves into an electrical signal, and a bottomed cylindrical outer shape having an open top and a penetrating hole that can accommodate the microphone element in the center of the bottom. A body conduction sensor having a hole made of a hard material, wherein the microphone element is fitted and held in a through-hole of the container, and the inner space of the container has an elastic polymer The surface of the elastic polymer material that is filled with the material and is exposed from the open end of the container becomes a sound wave input surface, and the converter surface of the microphone element sandwiches the elastic polymer material with respect to the sound wave input surface. The sound wave input when the sound wave input surface comes into contact with the human body surface is transmitted through the elastic polymer material to the transducer, and is a body conduction sound sensor.

  The container is formed of a conductive material, or is formed by covering a surface of an insulating material with a conductive material, and the microphone element has a conductive casing that surrounds the periphery of the converter, and the casing includes the casing. The conductive portion of the container is in contact with the human body surface by being electrically connected to the conductive portion of the container and the vibration input surface of the elastic polymer material being in contact with the human body surface.

  An area of the vibration input surface of the elastic polymer material is provided larger than an area of the through hole of the container, and the conversion body of the microphone element is disposed in the through hole.

  The inner wall of the container is formed in a cylindrical shape from the opening end to the bottom surface. Or you may form in the truncated cone shape from which the internal diameter becomes narrow toward the peripheral part of the said through-hole from the said opening end.

  The body-conducted sound sensor of the present invention detects the body-conducted sound with high sensitivity because the energy of the sound wave input to the sound wave input surface of the elastic polymer material is efficiently transmitted to the transducer for detecting sound waves of the microphone element. can do.

  In addition, by using an electret condenser type microphone element, the external body of the body conduction sensor can be reduced in size, and body conduction sound information can be easily sent to an analysis system such as a computer. A good body conduction sound analysis system can be constructed.

  In addition, if the container is formed of a conductive material and the structure of the container and the microphone element is grounded via the human body when measuring the body conduction sound, the induction noise generated in the output of the microphone element is significantly reduced. be able to.

  In addition, by forming the inside of the container into a predetermined shape that generates an amplifying action of vibration displacement based on the Pascal principle, it is possible to further increase the sensitivity of body conduction sound detection.

It is a longitudinal cross-sectional view which shows the body-conduction sound sensor of 1st embodiment of this invention. It is a disassembled perspective view which shows the structural member of the body-conduction sound sensor of 1st embodiment. It is a block diagram explaining the body conductance analysis system using the body conductance sensor of a first embodiment. It is a longitudinal cross-sectional view which shows the modification of the body-conduction sound sensor of 1st embodiment. It is a longitudinal cross-sectional view which shows the other modification of the body-conduction sound sensor of 1st embodiment. It is a longitudinal cross-sectional view which shows the body-conduction sound sensor of 2nd embodiment of this invention. It is a block diagram explaining the body sound analysis system using the body sound sensor of 2nd embodiment.

  Hereinafter, a body sound sensor 10 according to a first embodiment of the present invention will be described with reference to FIGS. The body-conducting sound sensor 10 is a body-contacting microphone that is brought into contact with the surface of the human body, extracts sound waves of body-conducting sound generated in the body or the body surface, converts the sound into electrical signals, and outputs the electrical signals. As shown in FIG. 2, the body sound sensor 10 includes a microphone element 12 having a cylindrical outer shape, a container 14 having a cylindrical outer shape having a bottom on one side, and a through hole 16 formed in the center of a bottom portion 14a, and a predetermined circuit. It is composed of a disk-shaped circuit board 18 on which elements are mounted and an elastic polymer material 20 filled in the inner space of the container 14 without a gap.

  As shown in FIGS. 1 and 2, the microphone element 12 has a metal housing 22 that is a cylindrical body with a closed lower end surface, and a diaphragm 24 that vibrates by receiving sound waves near the upper end. A fixed electrode plate 26 is provided so as to be exposed and opposed to the vicinity of the lower side of the diaphragm 24, and the diaphragm 24 and the fixed electrode plate 26 form a capacitor. That is, the converter that converts the input sound wave into an electrical signal is the diaphragm 24, and the movement of the diaphragm 24 that receives the sound wave is converted into a change in the capacitance of the capacitor and output as an electrical signal. Here, the diaphragm 24 is formed of a polymer film for electrets, which is a so-called electret condenser microphone. Since the electret condenser type microphone can maintain the electric charge in the diaphragm 24 by the electret effect, it is not necessary to supply a DC high voltage for polarization unlike a normal condenser type microphone. There is an advantage that the circuit configuration can be simplified.

  The container 14 is formed of a metal such as aluminum, and the inner side of the side wall 14b is dug into a cylindrical shape having an almost constant inner diameter from the open end 14c toward the bottom 14a. The through-hole 16 at the center of the bottom portion 14a is provided so that the housing 22 of the microphone element 12 can be inserted.

  The circuit board 18 has a disk-like outer shape substantially the same shape as the bottom portion 14a of the container 14, a predetermined circuit pattern is formed on the surface, and the housing 22 of the microphone element 12 is fixed to the front mounting surface, which is not shown. Lead terminals are wired in the circuit pattern. On the other hand, amplifying means 28 for amplifying the change in the capacitance of the microphone element 12 and outputting a signal is provided on the back side mounting surface.

  The main unit 11 is connected to the amplifying means 28 of the circuit board 18 via a cable 29 having a predetermined length. The main body 11 receives the output of the amplifying means 28 via the cable 29, converts it into a radio signal and outputs it, and supplies power to the microphone element 12 and the amplifying means 28 via the cable 29. In addition, power supply means 32 for supplying power to circuits such as the wireless transmission means 30 is also provided.

  The elastic polymer material 20 is a hydrophobic resin having an acoustic impedance characteristic equivalent to that of human skin in a cured state, and for example, a two-component curable urethane gel is suitable.

  The body sound sensor 10 is assembled by first attaching the microphone element 12 to the circuit board 18 on which the circuit element is mounted, inserting the microphone element 12 into the through-hole 16 from the outside of the bottom 14a of the container 14, and the housing 22 It is held in a state of being fitted to the inner wall of the through hole 16. With this fitting structure, the metal housing 22 and the metal container 14 are electrically connected. Further, the insertion position of the microphone element 12 is adjusted so that the diaphragm 24 is disposed near the outlet in the through hole 16. In the body conduction sensor 10 of this embodiment, as shown in FIG. 1, if the microphone element 12 is inserted until the front side mounting surface of the circuit board 18 abuts against the bottom portion 14 a of the container 14, the diaphragm 24 is in a desired position. It can be positioned easily.

  The circuit board 18 is preferably fixed to the container 14 using a screw member or the like (not shown). In order to protect the circuit elements of the circuit board 18, an insulating cover member (not shown) may be covered and fixed integrally with the screw member.

  A soft elastic polymer material 20 before curing is poured into the inner space of the container 14 from the open end 14c. At this time, the elastic polymer material 20 flows into the housing 22 of the microphone element 12 and covers the entire upper surface of the diaphragm 24 exposed upward. Then, it is left in a high temperature furnace and cured.

  When the elastic polymer material 20 is cured, the surface of the elastic polymer material 20 exposed from the container 14 becomes the sound wave input surface 20a that comes into contact with the skin of the human body, and is flush with the end surface of the open end 14c.

  Next, an actual operation of the body sound sensor 10 will be described together with a body sound analysis system 34 using the same. As shown in FIG. 3, the body conduction sound analysis system 34 includes a body conduction sound sensor 10 that is directly attached to the body surface of the measurement subject, a main body device 11 that is disposed near the measurement subject, and wireless reception. It comprises means 36 and an analysis means 38 and an external analysis device 40 such as a computer installed in a remote medical facility or the like. First, body conduction sound generated in the body of the measurement subject is observed by the body conduction sensor 10, and sound waves of the body conduction sound are extracted by the sound wave input surface 20 a of the elastic polymer material 20.

  The sound wave input to the sound wave input surface 20a is conducted to the diaphragm 24 of the microphone element 12 in the through hole 16 through the elastic polymer material 20, and the diaphragm 24 and the fixed diaphragm 26 are vibrated by the vibration of the diaphragm 24. The capacitance of the capacitor composed of and changes. At this time, since the elastic polymer material 20 has an acoustic impedance characteristic equivalent to that of human skin, impedance mismatch does not occur in the path from the skin to the diaphragm 24, and sound wave energy is hardly attenuated. Further, since the area S1 of the through hole 16 of the container 14 is narrower than the area S2 of the sound wave input surface 20a surrounded by the opening end 14c, the sound wave of the sound wave input surface 20a is almost based on the Pascal principle. The signal is amplified at a magnification corresponding to the area ratio (S2 / S1) and transmitted to the diaphragm 24.

  Since the change in the capacitor capacity of the microphone element 12 is a minute signal, it is amplified by the amplification means 28 into a large electric signal that is easy to handle. The amplified electrical signal is sent to the wireless transmission means 30 in the main body 11 located on the body side of the person to be measured through the cable 29, subjected to predetermined modulation processing, and wirelessly transmitted from the transmission antenna. . When performing communication using such radio waves, an FM communication method, a short-range wireless communication method called ZigBee, and the like are suitable. Further, depending on the environment and usage conditions in which the body conduction sound analysis system 34 is used, a wireless system such as optical communication using infrared as a medium may be adopted.

  The radio signal transmitted from the radio transmission unit 30 is received by the radio reception unit 36 of the external analysis device 40, subjected to demodulation processing, and various analysis is performed by the analysis unit 38. The obtained information is used for monitoring the condition of the person being measured and for diagnosis by a specialist.

  As described above, the body-conducting sound sensor 10 has a structure in which the microphone element 12 is directly fixed to the hard metal container 14, so that the sound wave energy is not dispersed and the sound wave detection vibration is efficiently performed. It is transmitted to the plate 24. Furthermore, since the inside of the container 14 has a predetermined cylindrical shape, a sound wave amplifying action based on Pascal's principle is generated, and the sensitivity of body conduction sound detection can be further improved.

  Further, the elastic polymer material 20 is widely covered with a metal container 14, the diaphragm 24 and the like inside the microphone element 12 are also covered with a casing 22 of a conductive material and conducted to the container 14, and the sound wave input surface 20 a is measured. When it touches the body surface, the open end 14c of the container 14 also comes into contact with the body surface and is electrically grounded through the human body. With this structure, the induction noise generated in the output of the microphone element 12 can be significantly reduced.

  In the body-conducting sound sensor 10, the electret condenser type microphone element 12 is selected, and it is not necessary to supply a DC high voltage dedicated to the microphone element 12. Operation is possible if voltage is supplied. Therefore, the power supply means 32 can be easily configured with a small button battery, a small battery, etc., and the body conduction sound sensor 10 and the main body device 11 can be reduced in size and weight. Thereby, even if it is worn on the body surface of the person to be measured, a good feeling of use can be obtained without disturbing the operation of the person to be measured, and by providing the wireless transmission means 30, the wireless body sound analysis system 34 can be provided. It can be easily configured.

  Next, a body sound sensor 50, which is a modification of the body sound sensor 10 of the first embodiment, will be described with reference to FIG. Here, the same components as those of the body sound sensor 10 are denoted by the same reference numerals and description thereof is omitted. The body sound sensor 50 is different from the body sound sensor 10 in that a container 52 is used in place of the container 14, and the other configurations are the same.

  The container 52 has a main body 54 formed of an insulating hard resin. The main body 54 has a cylindrical outer shape with a bottom on one side, the through hole 16 is formed in the center of the bottom portion 54a, and the inner side of the side wall 54b is a cone whose inner diameter narrows from the opening end 54c toward the peripheral edge of the through hole 16. It is formed in a trapezoid shape. The inner wall surface of the through hole 16 of the main body 54, the inner surface of the side wall 54b, and the surface of the opening end 54c are covered with a conductive layer 56 coated with a conductive material.

  Since most of the body 52 of the body sound sensor 50 is made of resin, the body sound sensor 50 can be further reduced in weight than the body sound sensor 10 using the metal container 14. Further, the main body 54 has a frustoconical shape, and can be efficiently manufactured by a method such as injection molding. Further, by providing the inner shape of the container 52 in the shape of a truncated cone, the attenuation characteristic when the sound wave of the input surface 20a is conducted to the diaphragm 24 is improved as compared with the container 14, and the sensitivity of body conduction sound detection is further improved. Can be made.

  Furthermore, induced noise generated in the output of the microphone element 12 can be reduced by the conductive layer 56 provided on the inner surface of the main body 54. This is because the elastic polymer material 20 is widely covered with the conductive layer 56, the diaphragm 24 and the like inside the microphone element 12 are also covered with the casing 22 of the conductive material and are conducted to the conductive layer 56, and the sound wave input surface 20a is measured. This is because the portion of the conductive layer 56 covering the open end 54c also comes into contact with the body surface and is electrically grounded through the human body by being applied to the body surface of the person.

  Next, a body sound sensor 60, which is another modification of the body sound sensor 10 of the first embodiment, will be described with reference to FIG. Here, the same components as those of the body sound sensor 10 are denoted by the same reference numerals and description thereof is omitted. The body conductance sensor 60 is different from the body conductance sensor 10 in that a container 62 is used instead of the container 14, and the other configurations are the same.

  The container 62 is formed of a metal such as aluminum, like the container 14, and the inner side of the side wall 62b is dug into a cylindrical shape having a substantially constant inner diameter from the opening end 62c toward the bottom 62a. However, the through hole 64 at the center of the bottom 62 a is formed larger than the housing 22 of the microphone element 12.

  The analysis of the body conduction sound is performed for various purposes, and the microphone element may be selected and changed each time depending on the purpose of the analysis. Even in such a case, if a large size of the through hole 64 of the container 62 is provided so that any of the plurality of microphone elements 12 that can be used can be accommodated, a plurality of microphone elements can be formed by one type of container 62. 12 is advantageous.

  In this case, the grounding structure for reducing the induction noise becomes a problem. For example, the housing 22 formed of the conductive material of the microphone element 12 is connected to the wiring pattern on the surface of the circuit board 18 and the wiring pattern is connected. If it is electrically connected to the metallic container 62 via the same, a grounding effect similar to that of the body sound sensor 10 can be obtained.

  Next, a body sound sensor 70 according to a second embodiment of the present invention will be described with reference to FIGS. Here, the same configuration as the body sound sensor 10 will be described with the same reference numerals. Similar to the body sound sensor 10, the body sound sensor 70 is mounted on the surface of the human body, extracts a sound wave of the body sound generated in the body or the body surface, converts it into an electrical signal, and outputs it. It is a sensor. As shown in FIG. 6, the body sound sensor 70 includes a microphone element 72 having a cylindrical outer shape, a container 14 having a cylindrical outer shape having a bottom on one side, and a through-hole 16 formed in the center of the bottom portion 14 a. It is comprised with the elastic polymer material 20 with which inner space was filled without gap. Unlike the body-conducting sound sensor 10, a circuit board on which amplification means and the like are mounted is not provided.

  As shown in FIG. 6, the microphone element 72 has a metal casing 22 that is a cylindrical body with a closed lower end surface, and a converter 74 that receives an acoustic wave and outputs an electrical signal near the upper end. It is exposed and provided. The converter 74 is arbitrarily selected from a normal capacitor type, a moving coil type, a piezoelectric type, and the like. A cable 76 such as a signal output line, a power supply line, and a ground line is drawn below the microphone element 72.

  The container 14 is formed of a metal such as aluminum, and the inner side of the side wall 14b is dug into a cylindrical shape having an almost constant inner diameter from the open end 14c toward the bottom 14a. The through-hole 16 at the center of the bottom portion 14a is provided so that the housing 22 of the microphone element 12 can be inserted.

  The elastic polymer material 20 is a hydrophobic resin having an acoustic impedance characteristic equivalent to that of human skin in a cured state, and for example, a two-component curable urethane gel is suitable.

  When assembling the body sound sensor 70, first, the microphone element 72 is inserted into the through hole 16 from the outside of the bottom portion 14a of the container 14, and the housing 22 is held in a state of being fitted to the inner wall of the through hole 16. Therefore, with this fitting structure, the metal housing 22 and the metal container 14 are in an electrically conductive state. Further, the insertion position of the microphone element 12 is adjusted so that the converter 74 is arranged near the outlet in the through hole 16.

  Next, the soft elastic polymer material 20 before curing is poured into the inner space of the container 14 from the opening end 14c. At this time, the elastic polymer material 20 also flows into the housing 22 of the microphone element 72 and covers the converter 74 exposed upward. Then, it is left in a high temperature furnace and cured.

  When the elastic polymer material 20 is cured, the surface of the elastic polymer material 20 exposed from the container 14 becomes the sound wave input surface 20a that comes into contact with the skin of the human body, and is flush with the end surface of the open end 14c.

  Next, an actual operation of the body conduction sound sensor 70 will be described together with a body conduction sound analysis system 78 using the same. As shown in FIG. 7, the body sound analysis system 78 includes a body sound sensor 70 to be worn on the human body of the person to be measured, an amplification means 28, a power supply means 32, and an analysis means 38. An external analysis device 80 that receives a signal via a cable 76 is configured.

  First, body-conducted sound generated in the body of the person to be measured is observed by the body-conducted sound sensor 70, and sound waves of the body-conducted sound are extracted from the sound wave input surface 20 a of the elastic polymer material 20. The sound wave input to the sound wave input surface 20a is conducted to the converter 74 of the microphone element 72 in the through hole 16 through the elastic polymer material 20, and is converted into an electric signal corresponding to the energy of the sound wave by the converter 74. . The point that impedance mismatch does not occur due to the acoustic impedance characteristic of the elastic polymer material 20 and that the sound wave is amplified due to the relationship between the shape of the container 14 and the Pascal principle are the same as those of the body-conduction sound sensor 10. It is.

  The output of the microphone element 72 is sent to the external analysis device 80 through the cable 76 and amplified by the amplification means 28 into an electric signal that can be easily handled. Then, using the amplified electrical signal, the analysis means 38 performs various analyzes, and a specialist makes a diagnosis based on the obtained information.

  As described above, the body-conducting sound sensor 70 can increase the sensitivity of the body-conducting sound detection in the same manner as the body-conducting sound sensor 10. Further, the induction noise can be significantly reduced by the same grounding structure.

  On the other hand, the body sound sensor 70 uses a microphone element 72 having a converter 74 such as a normal capacitor type, a moving coil type, and a piezoelectric type, and has excellent conversion characteristics that are characteristic of each. For example, when a normal condenser type is used as the microphone element 72, it is necessary to supply a high voltage to the microphone element 72. However, the body conduction sensor 70 is smaller and lighter than the body conduction sensor 10 described above. The entire system can be configured simply by, for example, eliminating the advantage of being able to do so and the circuit for wireless communication. Needless to say, the body sound sensor 70 may be configured using an electret condenser microphone element 72.

  The present invention is not limited to the above embodiment. For example, the outer shape of the container can be freely changed, such as a cylindrical shape, a rectangular tube shape, or a polygonal tube shape. The material of the container may be a hard conductive resin.

  The shape of the circuit board, the circuit element mounting method, the fixing method to the container, and the like can be freely changed. Moreover, the amplification means for amplifying the output of the converter may be provided in the microphone element.

10, 50, 60, 70 Body sound sensor 12, 72 Microphone element 14, 52, 62 Container 14c54c, 62c Open end 16, 64 Through hole 18 Circuit board 20 Elastic polymer material 20a Sound wave input surface 22 Housing 24 Diaphragm 28 Amplifying means 30 Wireless transmitting means 32 Power supply means 34 Body conduction sound analysis system 56 Conductive layer

Claims (6)

A microphone element provided with an exposed conversion body for converting sound waves into an electrical signal, and a bottomed cylindrical outer shape having an open upper end and a through-hole capable of accommodating the microphone element formed in the center of the bottom In a body sound sensor having a container made of a hard material and a circuit board to which the microphone element is fixed,
The circuit board is fixed to the outside of the bottom of the container in a state where the microphone element is accommodated in the through hole.
The inner space of the container is filled with an elastic polymer material, and the surface of the elastic polymer material exposed from the open end of the container is a sound wave input surface,
The converter surface of the microphone element is opposed to the sound wave input surface with the elastic polymer material interposed therebetween,
The container is formed of a conductive material, or is formed by covering the surface of an insulating material with a conductive material,
The microphone element has a conductive casing surrounding the converter, and the casing is electrically connected to the conductive portion of the container,
When the vibration input surface of the elastic polymer material contacts the human body surface, the conductive portion of the container contacts the human body surface,
The body acoustic sensor, wherein the elastic polymer material on the sound wave input surface comes into contact with the human body surface and the sound wave input from the human body surface is transmitted to the converter through the elastic polymer material.   The body conduction sensor according to claim 1, wherein the microphone element is of an electret condenser type, and the circuit board is provided with an amplifying means for amplifying the output of the microphone element. A microphone element provided with an exposed conversion body for converting sound waves into an electrical signal, and a bottomed cylindrical outer shape having an open upper end and a through-hole capable of accommodating the microphone element formed in the center of the bottom In a body sound sensor having a container made of hard material,
The microphone element is fitted and held in the through hole of the container,
The inner space of the container is filled with an elastic polymer material, and the surface of the elastic polymer material exposed from the open end of the container is a sound wave input surface,
The converter surface of the microphone element is opposed to the sound wave input surface with the elastic polymer material interposed therebetween,
The container is formed of a conductive material, or is formed by covering the surface of an insulating material with a conductive material,
The microphone element has a conductive casing surrounding the converter, and the casing is electrically connected to the conductive portion of the container,
When the vibration input surface of the elastic polymer material contacts the human body surface, the conductive portion of the container contacts the human body surface,
A body-conducted sound sensor, wherein sound waves input when the elastic polymer material on the sound wave input surface comes into contact with a human body surface are transmitted to the converter through the elastic polymer material. The area of the vibration input surface of the elastic polymer material is provided larger than the area of the through hole of the container,
The body conduction sensor according to claim 1 or 3, wherein the conversion body of the microphone element is disposed in the through hole.   The body sound sensor according to claim 4, wherein an inner wall of the container is formed in a cylindrical shape from the opening end to the bottom surface. The body conduction sensor according to claim 4, wherein the inner wall of the container is formed in a truncated cone shape having an inner diameter that narrows from the opening end toward a peripheral edge of the through hole.

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