Invention name: Stethoscope
Technical field
[0001]
　This disclosure relates to a stethoscope. In particular, the present invention relates to an electronic stethoscope provided with an electrocardiographic electrode for detecting the electrocardiogram of a measured object and capable of outputting the detected sound and electrocardiogram as data.
Background technology
[0002]
　Conventionally, a stethoscope equipped with an electrocardiographic electrode that can amplify and listen to sounds such as heart sounds and blood flow sounds generated inside the living body (hereinafter referred to as biological sounds) and detect the electrocardiogram of the object to be measured has been used. The following techniques are known.
[0003]
　For example, Japanese Patent Application Laid-Open No. 2012-55354 describes a hearing sound detection unit that detects a body sound, a tube that communicates with the hearing sound detection unit at one end and listens to the body sound from the other end, and a heart that is provided in the hearing sound detection unit. A diagnostic device including an electrocardiographic detection unit that detects an electric potential accompanying a beat and a control unit that converts the electric potential detected by the electrocardiographic detection unit into a radio signal and transmits the radio signal is described.
Outline of the invention
Problems to be solved by the invention
[0004]
　By the way, the electrocardiographic electrode may include three electrocardiographic electrodes having different functions. In this case, the direction of the output electrocardiographic signal changes depending on the positional relationship between the heart of the object to be measured and each electrode. If the user can easily determine which function the three electrocardiographic electrodes have in order to output the electrocardiographic signal in a predetermined direction, the operability of the user can be improved.
[0005]
　The present disclosure provides a stethoscope capable of improving user operability.
Means to solve problems
[0006]
　The first aspect of the present disclosure is a detection unit that detects vibration generated by a sound generated from an object to be measured and outputs a vibration signal based on the vibration, and an output unit that outputs a sound signal based on the vibration signal. The output terminal is a hearing device provided with an output terminal that outputs a sound signal to the outside, and three electrocardiographic electrodes that are arranged around the detection unit and detect the electrocardiogram of the object to be measured. It is arranged on the center of one of the three electrocardiographic electrodes and the axis passing through the center of the detection unit.
[0007]
　In the second aspect of the present disclosure, in the first aspect, the three electrocardiographic electrodes are a plus electrode, a minus electrode, and a reference electrode for measuring a reference level, respectively, and a predetermined electrocardiographic electrode is a reference electrode. There may be.
[0008]
　A third aspect of the present disclosure is the position in which the positive electrode and the negative electrode are around the detection unit and symmetrical with respect to the axis passing through the center of the reference electrode and the center of the detection unit in the second aspect. It may be arranged in each.
[0009]
　A fourth aspect of the present disclosure is, in the above aspect, an opening, a contact surface extending around the opening and in contact with an object to be measured, a back surface provided on the side opposite to the contact surface, and a contact surface. A support base with a side surface connected to the back surface and a back surface thereof is further provided, the detection unit is supported by the support base with a part of the surface exposed from the opening, and the output terminal is arranged on the side surface of the support base. It may have been done.
[0010]
　In a fifth aspect of the present disclosure, in the fourth aspect, the support base has a contact surface on the side surface and a constriction portion having a diameter smaller than the back surface, and the output terminal is on the back surface side of the constriction portion on the side surface. It may be arranged in.
[0011]
　A sixth aspect of the present disclosure may further include, in the fourth or fifth aspect, an input unit provided on the back surface and receiving an adjustment input of a sound signal level.
[0012]
　In the seventh aspect of the present disclosure, in the sixth aspect, the input unit may be a dial type.
[0013]
　In the eighth aspect of the present disclosure, in the fourth to seventh aspects, the support base may have a space for accommodating the battery, and may further have a charging terminal for charging the battery on the back surface. ..
The invention's effect
[0014]
　According to the above aspect, the stethoscope of the present disclosure can improve the operability of the user.
A brief description of the drawing
[0015]
FIG. 1 is a perspective view showing the back side of the stethoscope according to the first exemplary embodiment.
FIG. 2 is a perspective view showing the contact surface side of the stethoscope according to the first exemplary embodiment.
FIG. 3 is a diagram showing a contact surface of a stethoscope according to the first exemplary embodiment.
4 is a cross-sectional view taken along the line AA of FIG.
FIG. 5 is a cross-sectional view taken along the line AA of FIG. 3 when the stethoscope according to the first exemplary embodiment is pressed against a living body.
FIG. 6 is a diagram of a stethoscope filled with gas that supports a piezoelectric film.
FIG. 7 is a schematic diagram showing the configurations of a piezoelectric film and a protective layer.
FIG. 8 is a diagram for explaining the polarization action of the piezoelectric layer.
[Fig. 9] Fig. 9 is a graph in which the SN ratio is measured by changing the acoustic impedance of the protective layer.
[Fig. 10] Fig. 10 is a schematic diagram showing the configuration of a protective layer composed of a plurality of layers.
[Fig. 11] Fig. 11 is a schematic view showing the structure of a protective layer whose surface is made of a hydrophobic material.
FIG. 12 is a block diagram showing a configuration of a stethoscope according to the first exemplary embodiment.
FIG. 13 is a block diagram showing a configuration of an output unit according to the first exemplary embodiment.
FIG. 14 is a cross-sectional view taken along the line AA of FIG. 3 relating to the stethoscope according to the second exemplary embodiment.
FIG. 15 is a cross-sectional view taken along the line AA of FIG. 3 when the stethoscope according to the second exemplary embodiment is pressed against a living body.
Embodiment for carrying out the invention
[0016]
　Hereinafter, examples of embodiments for carrying out the technique of the present disclosure will be described in detail with reference to the drawings. Hereinafter, the living body 12 will be used as an example of the object to be measured, and the biological sound will be used as an example of the sound generated from the object to be measured. Examples of biological sounds include heartbeat sounds, respiratory sounds, blood flow sounds, intestinal sounds, and the like. Hereinafter, the piezoelectric film 30 will be used as an example of the detection unit.
[0017]
[First Exemplary Embodiment]
　First, the configuration of the stethoscope 10 according to this exemplary embodiment will be described with reference to FIGS. 1 to 3. As shown in FIGS. 1 to 3, the stethoscope 10 has an elasticity in which a support base 20, a piezoelectric film 30, a positive electrode 50P as an example of an electrocardiographic electrode, a negative electrode 50M, and a reference electrode 50R are arranged respectively. The sex members 52P, 52M, 52R and the like are provided.
[0018]
　The support base 20 has an opening 22, a first contact surface 24 extending around the opening 22 and in contact with the living body 12, and a back surface 26 provided on the side opposite to the first contact surface 24. It has a first contact surface 24 and a side surface 25 connected to the back surface 26. Further, the support base 20 has a constricted portion 28 having a diameter smaller than that of the first contact surface 24 and the back surface 26 on the side surface 25. Further, the support base 20 is made of a member that is harder than the elastic member 52 described later.
[0019]
　The support base 20 has an output terminal 80 on the side surface 25. The output terminal 80 is a terminal to which a signal indicating a biological sound (adjustment signal S3 described later) is output. The output terminal 80 includes, for example, an earphone jack to which the terminal of the earphone 14 for listening to the biological sound acquired by the stethoscope 10 is connected. It is preferable that the output terminal 80 is arranged on the back surface 26 side of the constricted portion 28 of the side surface 25. With such a configuration, when the user holds the constricted portion 28 by hand, the operability can be improved without the hand interfering with the terminal of the earphone 14 connected to the output terminal 80.
[0020]
　The support base 20 has an input unit 82, a display unit 84, and a charging terminal 86 for charging a battery 96, which will be described later, on the back surface 26. The input unit 82 is a part where an operation for adjusting the volume level of the biological sound heard by using the earphone 14 is performed. The input unit 82 includes, for example, a dial-type input component. By making the input unit 82 a dial type, it is possible to prevent the user from erroneously operating the input unit 82 as compared with the button type. The display unit 84 includes, for example, an LED light, and displays the remaining amount of the battery 96 and the like.
[0021]
　The elastic members 52P, 52M, 52R each have a second contact surface 54P, 54M, 54R that comes into contact with the living body 12, and are members having elasticity connected to the periphery of the support base 20, respectively. Hereinafter, when the elastic members 52P, 52M, and 52R are not distinguished, they are referred to as elastic members 52. When the second contact surface 54P, 54M, 54R is not distinguished, it is referred to as the second contact surface 54.
[0022]
　The elastic member 52 includes, for example, an elastomer material, a silicone resin, a silicone rubber, a urethane rubber, a natural rubber, a styrene butadiene rubber, a chloroprene rubber, an acrylic nitrile rubber, a butyl rubber, an ethylene propylene rubber, a fluororubber, and a clothosulfonated polyethylene rubber. It may be configured to include any one. The elasticity member 52 containing these materials has higher durability and lower flexibility as the thickness increases and the Young's modulus increases. When the flexibility is reduced, when the elastic member 52 is pressed against the living body 12, the hardness may cause discomfort.
[0023]
　Therefore, the elastic member 52 preferably has a thickness of 0.5 mm or more and 50 mm or less. The thickness is more preferably 3 mm or more and 30 mm or less, and most preferably the thickness is 5 mm or more and 20 mm or less. Further, the elastic member 52 preferably has a Young's modulus of 0.2 MPa or more and 50 MPa or less. It is more preferable that the Young's modulus is 0.2 MPa or more and 10 MPa or less. By setting the elastic member 52 to the thickness and Young's modulus in the above range, the elastic member 52 can be made into a member having appropriate durability and flexibility for use as a stethoscope.
[0024]
　The positive electrode 50P, the negative electrode 50M, and the reference electrode 50R for measuring the reference level are arranged on the second contact surfaces 54P, 54M, and 54R, respectively. That is, each of the three electrocardiographic electrodes of the positive electrode 50P, the negative electrode 50M, and the reference electrode 50R is arranged around the piezoelectric film 30. Hereinafter, when the positive electrode 50P, the negative electrode 50M, and the reference electrode 50R are not particularly distinguished, they are referred to as an electrocardiographic electrode 50.
[0025]
　The electrocardiographic electrode 50 is preferably removable from the elastic member 52. For example, the electrocardiographic electrode 50 and the elastic member 52 may be provided with a pair of coupling members (for example, a snap coupling member or the like). Further, for example, at least one of the electrocardiographic electrode 50 and the elastic member 52 may be provided with a removable adhesive member on the surface in contact with each other. Since the electrocardiographic electrode 50 is removable, the electrocardiographic electrode 50 can be replaced as appropriate.
[0026]
　As the electrocardiographic electrode 50, a commercially available disposable type electrocardiographic electrode can be used. The electrocardiographic electrode 50 preferably has adhesiveness on the surface in contact with the living body 12. Specifically, the adhesive strength measured by the following measuring method is preferably 0.25 N / mm (3N / 12 mm) or less.
[0027]
[180 ° peeling test]
　One end of the test piece with a width of 12 mm is attached to the end of the test plate, and immediately crimped with a crimping roller at a speed of 1 mm / s so that the other end side of the test piece remains as a pulling allowance. And stuck it on the test board. The test plate is set in a testing machine (AGS-X (manufactured by Shimadzu Corporation) or ZTA (manufactured by Imada Co., Ltd.)), and the test piece is peeled off from the test plate at a speed of 10 mm / s, and the measured value (N). ) Stabilized and the average of the measured values ​​from the end of peeling to the end of peeling was calculated and used as the value of adhesive strength.
[0028]
　The electrocardiogram detected by the electrocardiographic electrode 50 and the biological sound detected by the piezoelectric film 30 (details will be described later) can be obtained by contacting the stethoscope 10 with the living body 12 without moving the stethoscope 10 for a certain period of time. Detects biological sounds. Therefore, since the electrocardiographic electrode 50 has adhesiveness on the surface in contact with the living body 12, the stethoscope 10 can be fixed to the living body 12 and the stethoscope 10 can be prevented from moving easily. .. That is, since the electrocardiographic electrode 50 has adhesiveness, it is possible to suppress a decrease in the detection efficiency of the electrocardiogram and the biological sound when the stethoscope 10 is brought into contact with the living body 12.
[0029]
　In order for the electrocardiographic electrode 50 to detect the electrocardiogram of the living body 12 with sufficient accuracy, it is preferable that the electrocardiographic electrode 50 has a predetermined area. Therefore, it is preferable that the area of ​​each of the second contact surfaces 54 of the elastic member 52 on which the electrocardiographic electrode 50 is arranged is 100 mm 2 or more. By setting the area of ​​the second contact surface 54 to the area in the above range, the electrocardiographic electrode 50 having a sufficient area can be arranged, and the electrocardiogram can be detected with sufficient accuracy.
[0030]
　Here, the position of the output terminal 80 according to this exemplary embodiment will be described. When the electrocardiographic electrode 50 is brought into contact with the living body 12, the electrocardiographic signal S5 (details will be described later) is output depending on the positional relationship between the heart of the living body 12 and the positive electrode 50P, the negative electrode 50M, and the reference electrode 50R. The orientation changes. In order to output the electrocardiographic signal S5 in a specified direction, for example, the electrocardiographic electrode 50 is directed so that the reference electrode 50R faces the head side of the living body 12 and the positive electrode 50P and the negative electrode 50M face the leg side of the living body 12. It is assumed that it is required to determine the orientation of the living body 12 with respect to the living body 12. Therefore, it is desired that the user can easily determine which function the three electrocardiographic electrodes 50 have.
[0031]
　As shown in FIG. 3, the output terminal 80 is arranged on the axis AA passing through the center of a predetermined electrocardiographic electrode 50 out of the three electrocardiographic electrodes 50 and the center of the piezoelectric film 30. In this exemplary embodiment, the electrocardiographic electrode 50 arranged on the axes AA is the reference electrode 50R. Further, the positive electrode 50P and the negative electrode 50M are arranged around the piezoelectric film 30 at positions symmetrical with respect to the axes AA.
[0032]
　With such a configuration, the user can easily determine which electrocardiographic electrode 50 is the reference electrode 50R based on the position of the output terminal 80. Therefore, the operability of the user can be improved.
[0033]
　As shown in FIG. 3, the output terminal 80 is not limited to the one arranged at a position facing the reference electrode 50R with the piezoelectric film 30 interposed therebetween. For example, the output terminal 80 may be located on the axes AA and closest to the reference electrode 50R.
[0034]
　Further, the electrocardiographic electrode 50 arranged on the axes AA is not limited to the reference electrode 50R. It suffices if the three electrocardiographic electrodes 50 can be distinguished from each other in terms of the positional relationship with the output terminal 80, and the positive electrode 50P and the negative electrode 50M may be used as the electrocardiographic electrodes 50 arranged on the axes AA. ..
[0035]
　Next, with reference to FIGS. 3 to 5, the connection relationship between the support base 20 and the elastic member 52 according to this exemplary embodiment will be described. 4 and 5 are cross-sectional views taken along the line AA of FIG. 3, where FIG. 4 shows a case where the stethoscope 10 is not pressed against the living body 12, and FIG. 5 shows a case where the stethoscope 10 is pressed against the living body 12. ..
[0036]
　As described above, in order for the electrocardiographic electrode 50 to detect the electrocardiogram of the living body 12 with sufficient accuracy, the electrocardiographic electrode 50 needs to have a predetermined area. In addition, by arranging the three electrocardiographic electrodes 50 sufficiently apart, the influence of the myoelectricity of the living body 12 can be eliminated, and the electrocardiogram can be detected at a high SN ratio (Signal to Noise ratio). can.
[0037]
　As shown in FIG. 3, the support base 20 has three first connection sides 27P, 27M, 27R connected to the elastic members 52P, 52M, 52R, respectively, as the sides defining the first contact surface 24. Have. Each of the first connecting sides 27P, 27M, and 27R constitutes at least a part of each side of the triangle 58 including the first contact surface 24. Hereinafter, when the first connection sides 27P, 27M, and 27R are not particularly distinguished, they are referred to as the first connection side 27.
[0038]
　The elastic member 52P has a second connecting side 57P connected to the first connecting side 27P of the support base 20 as a side defining the second contact surface 54P. The length of the second connecting side 57P is equal to the length of the first connecting side 27P. Similarly, the elastic member 52M has a second connecting side 57M connected to the first connecting side 27M of the support base 20 as a side defining the second contact surface 54M. The length of the second connecting side 57M is equal to the length of the first connecting side 27M. Similarly, the elastic member 52R has a second connecting side 57R connected to the first connecting side 27R of the support base 20 as a side defining the second contact surface 54R. The length of the second connecting side 57R is equal to the length of the first connecting side 27R. Hereinafter, when the second connection sides 57P, 57M, and 57R are not particularly distinguished, they are referred to as the second connection side 57. Here, the length of the second connecting side 57 is "equal" to the length of the first connecting side 27, not only when they are completely equal, but also stably connected to the first connecting side 27. It suffices to have a length of about ± 10, for example, and may have a difference of about ± 10%. Further, the elastic member 52 has a shape that tapers toward a direction away from the second connecting side 57.
[0039]
　As shown in FIG. 4, in a state where the first contact surface 24 is not pressed against the living body 12, the elastic member 52R has an obtuse angle θ formed by the second contact surface 54R and the first contact surface 24. Is. The same applies to the elastic members 52P and 52M.
[0040]
　As shown in FIG. 5, the stethoscope 10 applies a pressure to press the first contact surface 24 of the support base 20 against the living body 12, so that the first contact surface 24 and the elastic member 52R come into second contact with each other. Each of the surfaces 54R is configured to extend in the same surface. The same applies to the elastic members 52P and 52M.
[0041]
　As described above, the elastic member 52 has a Young's modulus of 0.2 MPa or more and 50 MPa or less, and the support base 20 is made of a member harder than the elastic member 52. Therefore, in the elastic member 52, each of the first contact surface 24 and the second contact surface 54 extends in the same plane starting from the first connection side 27 and the second connection side 57. Can turn to. At this time, since the urging force acts in the direction of pressing the second contact surface 54 against the living body 12, the electrocardiographic electrode 50 and the living body 12 can be brought into close contact with each other, and the electrocardiogram can be detected at a high SN ratio. ..
[0042]
　The triangle 58 is not limited to the equilateral triangle as shown in FIG. For example, it may be an isosceles triangle in which the reference electrode 50R is arranged on the bottom surface and the positive electrode 50P and the negative electrode 50M are arranged on the equilateral sides.
[0043]
　Next, the configurations of the piezoelectric film 30 and the protective layer 40 according to this exemplary embodiment will be described with reference to FIGS. 4 and 6 to 11. FIG. 6 is an enlarged schematic view of a part of the piezoelectric film 30 and the protective layer 40 in order to show the configuration of the piezoelectric film 30 and the protective layer 40.
[0044]
　As shown in FIG. 4, the piezoelectric film 30 is supported by the support base 20 in a state where the surface exposed from the opening 22 is curved in a convex shape. Further, the surface exposed from the opening 22 of the piezoelectric film 30 projects with respect to the first contact surface 24.
[0045]
　Since the surface exposed from the opening 22 of the piezoelectric film 30 is curved in a convex shape, the piezoelectric film 30 expands and contracts in the in-plane direction as compared with the case where the piezoelectric film 30 is provided in a planar shape. Can be made larger. That is, by supporting the piezoelectric film 30 on the support base 20 in a state where the surface exposed from the opening 22 is curved in a convex shape, the amplitude of the voltage detected by the piezoelectric film 30 can be increased, and a high SN ratio can be obtained. It is possible to collect sound at.
[0046]
　The piezoelectric film 30 may be directly connected to a part of the support base 20, or may be connected to the support base 20 via another member such as an adhesive. Further, the piezoelectric film 30 has elasticity and flexibility to the extent that it does not crack when pressed against the living body 12.
[0047]
　A cushion material 38A is filled between the piezoelectric film 30 and the support base 20, and the piezoelectric film 30 is supported by the cushion material 38A so as to be curved in a convex shape. The cushion material 38A has an appropriate elasticity, supports the piezoelectric film 30, and gives a constant mechanical bias to the entire surface of the piezoelectric film 30. As a result, the vibration in the thickness direction generated in the piezoelectric film 30 can be converted into the expansion / contraction motion in the in-plane direction of the piezoelectric film 30, and the charge generation efficiency can be improved. Further, by changing the filling density of the cushion material 38A, a stethoscope 10 having an appropriate repulsive force can be realized.
[0048]
　The material of the cushion material 38A may be any material that has appropriate elasticity, does not prevent the piezoelectric film 30 from vibrating, and is appropriately deformed. Specifically, for example, alpha gel (registered trademark) (manufactured by Taica Corporation) using silicone as a main raw material, wool felt containing polyester fibers such as rayon and polyethylene terephthalate (PET), fiber materials such as glass wool, and polyurethane. It is preferable to use a foaming material such as. As shown in FIG. 6, gas 38B may be filled instead of the cushion material 38A.
[0049]
　As shown in FIG. 7, the piezoelectric film 30 has two main surfaces facing each other, a first main surface 32A which is the main surface on the side of the living body 12, and a main surface opposite to the side of the living body 12. It includes a piezoelectric layer 32 having a second main surface 32B, a first electrode 34 provided on the first main surface 32A, and a second electrode 36 provided on the second main surface 32B. ..
[0050]
　The piezoelectric layer 32 expands and contracts in the in-plane direction according to the biological sound emitted from the living body 12, and generates a voltage between the first electrode 34 and the second electrode 36 according to the expansion and contraction in the in-plane direction. Let me. In this exemplary embodiment, as the piezoelectric layer 32, it is possible to use a polymer composite piezoelectric body in which the piezoelectric particles 33 are dispersed in a matrix made of a polymer material. The piezoelectric particles 33 may be uniformly and uniformly dispersed in the matrix, or may be irregularly dispersed in the matrix.
[0051]
　The matrix is ​​viscous at room temperature, for example, cyanoethylated polyvinyl alcohol (cyanoethylated PVA), polyvinyl acetate, polyvinylidene chloride core acrylonitrile, polystyrene-vinyl polyisoprene block copolymer, polyvinylmethylketone, polybutylmethacrylate and the like. A polymer material having is preferable.
[0052]
　The piezoelectric particles 33 are piezoelectric particles, and are preferably ceramic particles having a perovskite-type crystal structure. Examples thereof include lead zirconate titanate, lead lanthanumate zirconate titanate, barium titanate, and a solid solution of barium titanate and bismuth ferrite.
[0053]
　As shown in FIG. 8, the piezoelectric layer 32 having such a configuration causes dielectric polarization in the thickness direction of the piezoelectric layer 32. In the case of the piezoelectric layer 32 that causes dielectric polarization in this way, the piezoelectric layer 32 generates a positive charge on the side of the second main surface 32B and a negative charge on the side of the first main surface 32A. It is preferable to arrange. It is known that the living body 12 is usually positively charged in many cases. Therefore, by arranging the piezoelectric layer 32 so as to generate a negative charge on the side of the first main surface 32A, which is the surface on the side in contact with the living body 12, the biological sound can be efficiently detected.
[0054]
　As the piezoelectric layer 32, an organic piezoelectric film such as polyvinylidene fluoride (PVDF), vinylidene-ethylene trifluoride copolymer (P (VDF-TrFE)), or polylactic acid may be used. Further, as the piezoelectric layer 32, an organic material such as a polymer electret material containing a polymer as a main component described in JP-A-2018-191394, JP-A-2014-233688, and JP-A-2017-12270 is used. You may. For example, polyimide, polytetrafluoroethylene, polypropylene, and PTFE (polytetrafluoroethylene (tetrafluoroethylene)), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene). Examples thereof include Teflon (registered trademark) such as polymer (4.6 fluoride)) AF (amorphous fluoropolyma), polyethylene, and COCs (cycloolefin polymer).
[0055]
　However, when PVDF is used as the piezoelectric layer 32 instead of the polymer composite piezoelectric material, dielectric polarization occurs in the in-plane direction. In this case, the SN ratio may be lower than that of the polymer composite piezoelectric material in which dielectric polarization occurs in the thickness direction.
[0056]
　The first electrode 34 and the second electrode 36 detect in-plane expansion and contraction of the piezoelectric layer 32 as a voltage. The thickness of the first electrode 34 and the second electrode 36 is not particularly limited, but is preferably thin in order to secure the flexibility of the piezoelectric film 30, and is preferably 1 μm or less, for example. The thicknesses of the first electrode 34 and the second electrode 36 may be the same or different.
[0057]
　The materials of the first electrode 34 and the second electrode 36 are a thin film of copper (Cu) and aluminum (Al) formed by vacuum deposition to ensure the flexibility of the piezoelectric film 30, and a conductive polymer. Etc. are preferable.
[0058]
　Various conductors may be used as the material of the first electrode 34 and the second electrode 36. For example, C, Pd, Fe, Sn, Ni, Pt, Au, Ag, Cr and Mo, and alloys thereof may be used. Further, a transparent conductive film such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide, and zinc oxide may be used. Further, an organic conductor such as a conductive polymer may be used. The method for forming the electrodes is also not particularly limited, and there are various methods such as film formation by a vapor deposition method (vacuum deposition method) such as vacuum deposition and sputtering, screen printing, and a method of attaching a foil formed of the above materials. A known method may be used.
[0059]
　The size of at least one of the first electrode 34 and the second electrode 36 may be smaller than that of the piezoelectric layer 32. In particular, as shown in FIG. 4, it is preferable that the first electrode 34 is provided only in the central portion of the first main surface 32A. In addition to the function of detecting the biological sound emitted from the living body 12, the first electrode 34 may function as an antenna and take in electromagnetic noise from the outside. In order to suppress the capture of electromagnetic noise, it is preferable to reduce the size of the first electrode 34 within a range in which it is difficult to capture electromagnetic noise and biological sound can be sufficiently detected. By providing the first electrode 34 only in the central portion of the first main surface 32A in contact with the living body 12, it is possible to suppress the intake of electromagnetic noise and to collect sound at a high SN ratio.
[0060]
　Since the surface of the piezoelectric film 30 exposed from the opening 22 is convexly curved and protrudes from the first contact surface 24, the piezoelectric film 30 is different from the living body 12 as compared with the case where the piezoelectric film 30 is provided in a planar shape. If it comes into direct contact, it will be easily damaged. Therefore, it is preferable to arrange the protective layer 40 on the surface of the piezoelectric film 30 on the side in contact with the living body 12. By arranging the protective layer 40 on the surface of the piezoelectric film 30 on the side in contact with the living body 12, damage to the piezoelectric film 30 can be prevented.
[0061]
　Further, when the piezoelectric film 30 detects the vibration of the living body 12, if the difference in acoustic impedance (unit: MRayls = kg / m 2 s), which is a value peculiar to each substance, is large, the sound is reflected and the living body sound. Detection efficiency is reduced. That is, the noise ratio increases and the SN ratio decreases. Therefore, it is preferable that the protective layer 40 has an acoustic impedance between the acoustic impedance of the living body 12 and the acoustic impedance of the piezoelectric film 30 in order to alleviate the difference in acoustic impedance between the living body 12 and the piezoelectric film 30. ..
[0062]
　FIG. 9 is a graph obtained by measuring the SN ratio of the sound signal S2 (details will be described later) output from the stethoscope 10 when the acoustic impedance of the protective layer 40 is changed. In FIG. 9, the horizontal axis shows the acoustic impedance (MRayls) of the protective layer 40, and the vertical axis shows the SN ratio (dB) of the sound signal S2.
[0063]
　The acoustic impedance of the living body 12 is known to be 1.3 to 1.5 MRayls, and the acoustic impedance of the piezoelectric film 30 is 5.0 to 10.0 MRayls. When the acoustic impedance of the protective layer 40 is 1.3 MRayls or more and 5.0 MLayls or less between the acoustic impedance of the living body 12 and the acoustic impedance of the piezoelectric film 30, it is output from the auditorium 10 as shown in FIG. The SN ratio of the sound signal S2 could be stably set to 60 dB or more. That is, by providing the protective layer 40 in which the acoustic impedance is matched between the living body 12 and the piezoelectric film 30, it is possible to suppress the reflection of sound, and it is possible to collect sound at a high SN ratio. ..
[0064]
　The protective layer 40 is any one of elastomer material, silicone resin, silicone rubber, urethane rubber, natural rubber, styrene butadiene rubber, chloroprene rubber, acrylic nitrile rubber, butyl rubber, ethylene propylene rubber, fluororubber and crososulfonated polyethylene rubber. It is preferable to use one. Since the protective layer 40 is directly pressed against the living body 12, it is desired that the protective layer 40 is a material that does not cause discomfort due to coldness or hardness to the living body 12. By using the above-mentioned material, it is possible to suppress the occurrence of discomfort even when the protective layer 40 is pressed against the living body 12.
[0065]
　Since the protective layer 40 is directly pressed against the living body 12, it is desired to have wear resistance. Therefore, it is preferable that the protective layer 40 has a measured value of 50 or more and 100 or less in a hardness test using a type A durometer compliant with ASTM D2240. The hardness measured by a durometer of another standard and another measuring method may be equivalent to the hardness in the above test method. By setting the protective layer 40 to a hardness in the above range, it is possible to have appropriate wear resistance for use as a stethoscope.
[0066]
　If the protective layer 40 has high rigidity, it restrains the expansion and contraction of the piezoelectric layer 32, and the vibration of the piezoelectric film 30 becomes small. Therefore, the thickness of the protective layer 40 having the above-mentioned material and hardness may be appropriately set according to the performance, handleability, mechanical strength, and the like required for the piezoelectric film 30. Specifically, it may be about 500 μm.
[0067]
　It is preferable that the surface of the protective layer 40 in contact with the living body 12 is roughened. Since the protective layer 40 is directly pressed against the living body 12, it is desirable that the protective layer 40 be easily peeled off from the skin of the living body 12. The roughening treatment method is not particularly limited, and various known methods such as mechanical roughening treatment, electrochemical roughening treatment, and chemical roughening treatment may be used. The roughness of the surface of the protective layer 40 in contact with the living body 12 is preferably an arithmetic average roughness Ra of 0.1 μm or more and 100 μm or less, and preferably 0.1 μm or more and 10 μm or less. More preferred. By making the protective layer 40 rough in the above range, it can be easily peeled off from the skin of the living body 12.
[0068]
　The protective layer 40 may be a layer in which the acoustic impedance is inclined so that the acoustic impedance becomes lower toward the side in contact with the living body 12. Further, the protective layer 40 may be composed of a plurality of layers laminated so that the acoustic impedance becomes lower toward the layer on the side in contact with the living body 12. For example, as shown in FIG. 10, when the protective layer 40 is composed of four layers, the acoustic impedance may be lowered in the order of the protective layers 41, 42, 43, 44. In this case, the materials of the plurality of layers may be different, and a material consisting of at least one of the above-mentioned materials may be used. By having such a configuration of the protective layer 40, the difference in acoustic impedance between adjacent substances can be made smaller, and sound can be collected at a higher SN ratio.
[0069]
　Further, the protective layer 40 has a surface in contact with the living body 12 made of a silicone resin, and the silicone resin has a siloxane skeleton as a main chain skeleton and a methyl group, a vinyl methyl group and a phenyl methyl group as hydrophobic side chains. It may have at least one of. The surface of the living body 12 may be wet due to sweat or the like. Since the protective layer 40 is directly pressed against the living body 12, it is desired that at least the surface in contact with the living body 12 is made of a material that is not denatured by water. Therefore, for example, as shown in FIG. 11, the protective layer 40 is composed of a protective layer 46 whose acoustic impedance is matched, and a protective layer 47 which is a surface in contact with the living body 12 and is made of a hydrophobic material. It may be configured. Since the surface in contact with the living body 12 is hydrophobic, it is possible to prevent the protective layer 40 and the piezoelectric film 30 from being denatured even when the protective layer 40 is pressed against the wet living body 12.
[0070]
　Next, with reference to FIG. 12, the function of the stethoscope 10 according to this exemplary embodiment will be described. As shown in FIG. 12, the stethoscope 10 includes a piezoelectric film 30, an electrocardiographic electrode 50, an output terminal 80, an input unit 82, a display unit 84, and a charging terminal 86. Further, the stethoscope 10 includes an output unit 60, a processing unit 90, a communication unit 92, a power unit 94, and a battery 96. The output unit 60, the processing unit 90, the communication unit 92, the power unit 94, and the battery 96 may be housed in the storage unit 29, which is the space of the support base 20 (see FIG. 4), and may be provided outside the support base 20. It may be something that can be done.
[0071]
　The piezoelectric film 30 detects the vibration generated by the biological sound generated from the living body 12, and outputs the vibration signal S1 to the output unit 60 based on the vibration. Specifically, when the surface of the living body 12 vibrates due to the biological sound generated from the living body 12, when the piezoelectric film 30 is brought into contact with the living body 12, the piezoelectric film 30 also vibrates according to the vibration. The piezoelectric film 30 detects vibration as a voltage generated between the first electrode 34 and the second electrode 36, and outputs the detected voltage to the output unit 60 as a vibration signal S1.
[0072]
　The input unit 82 receives the adjustment input of the level of the sound signal S2 output from the output unit 60 described later, and outputs the adjustment input signal S4 indicating the received adjustment input information to the output unit 60.
[0073]
　The output unit 60 outputs the sound signal S2 to the processing unit 90 based on the vibration signal S1. Further, the output unit 60 adjusts the level of the sound signal S2 according to the level change of the vibration signal S1 and the adjustment input signal S4, and outputs the adjustment signal S3 to the output terminal 80. The output terminal 80 outputs the adjustment signal S3 to the outside.
[0074]
　The electrocardiographic electrode 50 detects the electrocardiogram of the living body 12. Specifically, by bringing the electrocardiographic electrode 50 into contact with the vicinity of the heart of the living body 12, the potential on the body surface of the living body 12 is detected and output to the processing unit 90 as an electrocardiographic signal S5.
[0075]
　The processing unit 90 performs predetermined processing on the data based on the sound signal S2 and the electrocardiographic signal S5, and outputs the processed data to the communication unit 92. The processing unit 90 may include an amplifier circuit, a filter circuit, and the like, and may amplify the sound signal S2 and the electrocardiographic signal S5, or extract a specific frequency. Further, the data based on the sound signal S2 and the electrocardiographic signal S5 may be output as analog data or may be output as digital data. The processing unit 90 may be configured by, for example, a microcomputer including a CPU (Central Processing Unit) 60, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.
[0076]
　The communication unit 92 includes a wired or wireless communication means, and transmits biological sound and electrocardiographic data to an external device. The communication means may be, for example, Bluetooth (registered trademark), infrared communication, or the like, and the external device may be, for example, a personal computer, a smartphone, or the like.
[0077]
　The power unit 94 charges the battery 96 with the electric power supplied from the charging terminal 86. Further, the power unit 94 supplies the electric power charged in the battery 96 to the output unit 60, the display unit 84, the processing unit 90, and the communication unit 92.
[0078]
　Further, the processing unit 90 acquires information indicating the remaining battery level of the battery 96 via the power unit 94, and controls such as turning on, extinguishing, and blinking the LED light of the display unit 84 based on the acquired information. You may. In this case, the user can grasp the remaining battery level of the battery 96 by the light emitting state of the LED light. Similarly, when the sound signal S2 and the electrocardiographic signal S5 can be normally acquired, the display unit 84 may be controlled or the like. In this case, the user can grasp the acquisition state of the sound signal S2 and the electrocardiographic signal S5 depending on the display mode of the display unit 84.
[0079]
　Next, the function of the output unit 60 will be described with reference to FIG. As shown in FIG. 13, the output unit 60 includes a buffer 61, a filter circuit 62, amplifiers 63 and 65, and an ALC (Automatic Level Control) circuit 64.
[0080] [0080]
　The vibration signal S1 detected by the piezoelectric film 30 is input to the filter circuit 62 via the buffer 61, noise is cut by the filter circuit 62, amplified by the amplifier 63, and used as the sound signal S2 by the processing unit 90 and the ALC. It is output to the circuit 64. The filter circuit 62 is, for example, a low-pass filter.
[0081]
　When the stethoscope 10 is brought into contact with the living body 12 and then separated from the living body 12 after the auscultation, the piezoelectric film 30 vibrates greatly, and steep noise (spike noise) may be mixed in the vibration signal S1. .. If the spike noise is output as the sound signal S2 from the output terminal 80 as it is, the sound heard from the earphone connected to the output terminal 80 becomes a jarring sound. Therefore, it is desirable to reduce the spike noise by the ALC circuit 64.
[0082]
　The adjustment input signal S4 and the sound signal S2 from the input unit 82 are input to the ALC circuit 64. The ALC circuit 64 is, for example, a Schottky barrier diode for detecting spike noise from the sound signal S2, a capacitor for smoothing the sound signal S2, and a MOSFET (Metal-Oxide) driven when spike noise is detected. -Semiconductor Field-Effect Transistor) and the like may be included. The ALC circuit 64 uses these elements to reduce spike noise and adjust the level of the sound signal S2 based on the adjustment input signal S4.
[0083]
　The sound signal S2 whose spike noise is reduced by the ALC circuit 64 and whose level is adjusted is amplified by the amplifier 65 and output to the output terminal 80 as the adjustment signal S3.
[0084]
　As described above, according to the stethoscope 10 according to the present exemplary embodiment, the piezoelectric film 30 is supported by the support base 20 in a state where the surface exposed from the opening 22 is curved in a convex shape, and the piezoelectric film 30 is supported by the support base 20. A protective layer 40 having an acoustic impedance between the acoustic impedance of the living body 12 and the acoustic impedance of the piezoelectric film 30 is provided on the surface of the film 30 on the side in contact with the living body 12. Therefore, the biological sound can be detected at a high SN ratio.
[0085]
　Further, according to the stethoscope 10 according to the present exemplary embodiment, the output terminal 80 is on a shaft passing through the center of a predetermined electrocardiographic electrode among the three electrocardiographic electrodes 50 and the center of the piezoelectric film 30. Is located in. Therefore, the operability of the user can be improved.
[0086]
　Further, according to the stethoscope 10 according to the present exemplary embodiment, the elastic member 52 has an obtuse angle with the first contact surface 24, and among the sides defining the second contact surface 54. It is an elastic member connected to each of the first connecting sides 27 at the second connecting side 57 having the same length as the first connecting side 27. Therefore, the electrocardiographic electrodes 50 can have a predetermined area while suppressing the increase in the size of the stethoscope 10 itself, and the three electrocardiographic electrodes 50 can be arranged sufficiently apart from each other. That is, it is possible to detect the electrocardiogram with a high SN ratio while improving the operability of the user.
[0087]
[Second Exemplary Embodiment]
　Next, the configuration of the stethoscope 10 according to this exemplary embodiment will be described with reference to FIGS. 14 and 15. In FIGS. 14 and 15, elements equivalent to the elements described in the first exemplary embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
[0088]
　When the stethoscope 10 is supported by the support base 20 in a convexly curved state as in the stethoscope 10 according to the first exemplary embodiment, when the stethoscope 10 is pressed against the living body 12, the piezoelectric film is formed. A portion near the outer periphery of the living body 12 may be in a floating state from the surface of the living body 12. For example, when a patient who does not have specialized skills in telemedicine or the like uses the stethoscope 10, the stethoscope 10 cannot be pressed vertically against the living body 12, or the stethoscope 10 is pressed against the living body 12 with sufficient pressure. It can happen that they are not pressed. When the piezoelectric film 30 is in a floating state, the piezoelectric film 30 can easily detect external sounds such as environmental sounds and human voices (hereinafter referred to as external sounds) as noise, and the SN ratio is lowered.
[0089]
　Therefore, as shown in FIG. 14, the stethoscope 10 according to the present exemplary embodiment has the configuration of the stethoscope 10 according to the first exemplary embodiment and the outer periphery of the portion exposed from the opening 22 of the piezoelectric film 30. A sound insulating member 70 that surrounds the above and shields the external sound transmitted to the piezoelectric film 30 is further provided. Further, the tip of the sound insulating member 70 projects from the convexly curved surface of the piezoelectric film 30. The protruding height of the sound insulating member 70 is preferably 1 mm or more.
[0090]
　The sound insulating member 70 has enough elasticity to compress and deform the entire surface of the piezoelectric film 30 exposed from the opening 22 so that it can come into contact with the living body 12 when the stethoscope 10 is vertically pressed against the living body 12. .. The sound insulating member 70 preferably has a high effect of absorbing external sound, such as a fiber-based material such as glass wool and a foam material such as urethane foam.
[0091]
　FIG. 15 shows a state in which the stethoscope 10 according to this exemplary embodiment is pressed against the living body 12. When the stethoscope 10 is pressed against the living body 12, the sound insulating member 70 is compressed according to the pressed pressure. For example, as shown in FIG. 15, when the stethoscope 10 is obliquely pressed against the living body 12, the degree of compression of the sound insulating member 70 is large in the place where the pressure is large, and the compression of the sound insulating member 70 is in the place where the pressure is small. The degree of is small. With such a configuration, even if the stethoscope 10 is not pressed vertically against the living body 12 or the stethoscope 10 is not pressed against the living body 12 with sufficient pressure, the piezoelectric film 30 makes an external sound. Can be suppressed from being detected.
[0092]
　As described above, according to the stethoscope 10 according to the present exemplary embodiment, the sound insulating member surrounds the outer periphery of the portion exposed from the opening 22 of the piezoelectric film 30 and shields the external sound transmitted to the piezoelectric film 30. 70 is further provided. Therefore, when the auditory apparatus 10 is pressed against the living body 12, the piezoelectric film 30 can be surrounded by the sound insulating member 70, and the piezoelectric film 30 can be prevented from detecting external sound as noise. Biological sounds can be detected at a high SN ratio.
[0093]
　In the stethoscope 10 according to each of the above exemplary embodiments, the object to be measured is not limited to the living body 12, and the object to be measured may be a machine, piping, or the like. That is, by detecting the sound generated from the machine, the pipe, or the like as the sound generated from the object to be measured, it can be used for detecting an abnormality in the machine or the pipe.
[0094]
　The disclosure of Japanese patent application 2019-138273 filed on July 26, 2019 is incorporated herein by reference in its entirety. Also, all documents, patent applications and technical standards described herein are to the same extent as if the individual documents, patent applications and technical standards were specifically and individually stated to be incorporated by reference. , Incorporated by reference herein.
The scope of the claims
[Claim 1]
　A detection unit that detects vibration generated by sound generated from an object to be measured and outputs a vibration signal based on the vibration,
　an output unit that outputs a sound signal based on the vibration signal, and
　an external sound signal. The output terminal is provided with an output terminal,
　each of which is arranged around the detection unit and detects the electrocardiogram of the object to be measured, and the
　output
　terminal is of the three electrocardiographic electrodes. A hearing device arranged on an axis passing through the center of one of the predetermined electrocardiographic electrodes and the center of the detection unit
　.
[Claim 2]
　The stethoscope according to claim 1, 　wherein the three electrocardiographic electrodes are a positive electrode, a negative electrode, and a reference electrode for measuring a reference level, respectively, and the
　predetermined electrocardiographic electrode is a reference electrode .
[Claim 3]

　The stethoscope according to claim 2, 　wherein the positive electrode and the negative electrode are arranged around the detection unit and at positions symmetrical with respect to the axis .
[Claim 4]
　An opening, a contact surface extending around the opening and in contact with the object to be measured, a back surface provided on the side opposite to the contact surface, and a side surface connected to the contact surface and the back surface. The detection unit is further supported by the support table with a
　part of the surface exposed from the opening, and the
　output terminal is arranged on the side surface of the support table.
　The stethoscope according to any one of claims 1 to 3 .
[Claim 5]
　4. The support base has a contact surface on the side surface and a constricted portion having a diameter smaller than that on the back surface, and the
　output terminal is arranged on the back surface side of the constricted portion on the side surface
　. Stethoscope described in.
[Claim 6]

　The stethoscope according to claim 4 or 5, 　further comprising an input unit provided on the back surface and receiving an input for adjusting the level of the sound signal .
[Claim 7]

　The stethoscope according to claim 6, 　wherein the input unit is a dial type .
[Claim 8]
　The stethoscope according to any one of claims 4 to 7, 　wherein the support base has a space for accommodating a battery,
　and further includes a charging terminal for charging the battery on the back surface .