Biosound detection device

Abstract

To provide a biological sound detection device capable of suppressing deterioration of detection accuracy.SOLUTION: The device comprises: a sensor unit 10 comprising a sensor element 11 which outputs a detection signal corresponding to a biological sound and a casing 12 which houses the sensor element 11; and a sheet part 20 which has the sensor unit 10 disposed internally and with which a human body is brought into contact. In the sensor unit 10 and the sheet part 20, a resonance frequency is a frequency different from a detection frequency band, with respect to the detection frequency band in a predetermined range including the frequency of the biological sound.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a biological sound detection device that detects biological sounds of a human body.

Background Art

[0002] Conventionally, a biological sound detection device that detects biological sounds of a human body using a sensor unit having a piezoelectric element or the like has been proposed (for example, see Patent Document 1). Specifically, in this biological sound detection device, the sensor unit is provided directly or indirectly on the human body via clothing or the like, and a detection signal based on the biological sound is output from the sensor unit. Then, the biological sound is grasped based on the detection signal. Note that the biological sound is a heart sound or the like of the human body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the inventors of the present invention have been studying a biological sound detection device that arranges a sensor unit inside a seat part where a human body sits or lies down, and the sensor unit detects biological sounds in a state of being non-restrained with respect to the human body. However, when the inventors studied such a biological sound detection device, it was confirmed that the detection accuracy may decrease depending on the configuration of the sensor unit and the seat part.

[0005] In view of the above points, an object of the present invention is to provide a biological sound detection device capable of suppressing a decrease in detection accuracy.

Means for Solving the Problems

[0006] Claim 1 for achieving the above objective is a biosound detection device for detecting biosounds of the human body, comprising: a sensor unit (10) having a sensor element (11) that outputs a detection signal corresponding to the biosound and a housing (12) that houses the sensor element; and a sheet unit (20) in which the sensor unit is arranged and which comes into contact with the human body, wherein the sensor unit and the sheet unit have resonant frequencies (f1, f2) that are different from the detection frequency band with respect to a predetermined range of detection frequency bands that include the frequency of the biosound. The resonant frequency (f1) of the sensor part is given by the value shown in Equation 1 below, where m1 is the mass of the sensor element and k1 is the spring constant of the sensor element. The sheet part has a skin (21) that comes into contact with the human body and an internal member (23) that is positioned on the opposite side of the skin from the human body and covers at least a part of the sensor part. The resonant frequency (f2) of the sheet part is given by the value shown in Equation 2 below, where m2 is the mass of the housing, and m3 is the mass of the part of the internal member that overlaps when the sensor part is projected from the skin side and when the sensor part overlaps when it is projected from the opposite side of the skin side, and k3 is the spring constant. .

number

number

number

number

[0007] According to this, the sensor and sheet components have resonant frequencies that differ from the detection frequency band. Therefore, a decrease in detection accuracy can be suppressed.

[0008] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of the heart sound detection device in the first embodiment. [Figure 2] This diagram illustrates the relationship between the detection frequency band, heart sounds, and biological noise. [Figure 3] This is a diagram to explain the problem. [Figure 4]It is a diagram showing the relationship between the detection frequency band in the first embodiment, the resonance frequency of the sensor unit, and the resonance frequency of the sheet unit. [Figure 5] It is a diagram for explaining the spring-mass system in the first embodiment. [Figure 6A] It is a cross-sectional view showing a configuration for increasing the mass of the sensor unit in the first embodiment. [Figure 6B] It is a cross-sectional view showing a configuration for increasing the mass of the sensor unit in the first embodiment. [Figure 6C] It is a cross-sectional view showing a configuration for increasing the mass of the sensor unit in the first embodiment. [Figure 7A] It is a cross-sectional view showing a configuration for increasing the mass of the sheet unit in the first embodiment. [Figure 7B] It is a cross-sectional view showing a configuration for increasing the mass of the sheet unit in the first embodiment. [Figure 7C] It is a cross-sectional view showing a configuration for increasing the mass of the sheet unit in the first embodiment. [Figure 7D] It is a cross-sectional view showing a configuration for increasing the mass of the sheet unit in the first embodiment. [Figure 7E] It is a cross-sectional view showing a configuration for increasing the mass of the sheet unit in the first embodiment. [Figure 8] It is a diagram for explaining the regression equation of the resonance frequency of the sheet unit. [Figure 9] It is a cross-sectional view showing a configuration for increasing the thickness of the sheet unit. [Figure 10] It is a diagram showing the relationship between the detection frequency band in the second embodiment, the resonance frequency of the sensor unit, and the resonance frequency of the sheet unit. [Figure 11] It is a cross-sectional view showing a configuration for reducing the thickness of the sheet unit. [Figure 12] It is a diagram showing the relationship between the detection frequency band in the third embodiment, the resonance frequency of the sensor unit, and the resonance frequency of the sheet unit.

Embodiments for Carrying Out the Invention

[0010] The embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be denoted by the same reference numerals.

[0011] (First Embodiment) The first embodiment will be described with reference to the drawings. In this embodiment, a heart sound detection device for detecting heart sounds as biological sounds will be described. As shown in Figure 1, the heart sound detection device of this embodiment is configured to include a sensor unit 10 and a seat unit 20, etc., and is preferably applied to, for example, a bed, a chair, or the driver's seat or passenger seat of a vehicle.

[0012] The sensor unit 10 comprises a sensor element 11 and a housing 12.

[0013] In this embodiment, the sensor element 11 is composed of a thin-film piezoelectric element and outputs a detection signal corresponding to the heart sound when a heart sound is applied. The sensor element 11 is housed in the housing section 12a of the housing 12, as will be described later, and the heart sound is applied through the housing 12.

[0014] The housing 12 is box-shaped and has a storage section 12a made of acrylic resin or metal, and the sensor element 11 is housed in the storage section 12a. Although not shown in the figures, the housing 12 has a connector section formed at a predetermined location on the wall surface that is electrically connected to the sensor element 11. The sensor element 11 is electrically connected to the external wiring section by connecting the external wiring section to the connector section.

[0015] The seat portion 20 is configured to include a surface 21 that comes into contact with the human body, a support portion 22 on the opposite side of the surface 21, and an internal member 23 positioned between the surface 21 and the support portion 22. For example, the surface 21 is made of cloth, synthetic leather, genuine leather, etc., the internal member 23 is made of a cushioning material such as urethane, and the support portion 22 is made of a wooden board, acrylic board, iron plate, etc. that is harder than the internal member 23. In this embodiment, the internal member 23 is sufficiently thicker than the surface 21 and the support portion 22.

[0016] The sensor unit 10 is positioned between the outer skin 21 and the support unit 22. In this embodiment, the sensor unit 10 (i.e., the housing 12) is box-shaped with one surface 10a, another surface 10b, and a side surface 10c, with one surface 10a in contact with the outer skin 21, while the other surface 10b and the side surface 10c are covered by the internal member 23. The sensor element 11 in this embodiment is provided on the side of the housing 12a, specifically on the side of the one surface 10a.

[0017] The above describes the basic configuration of the heart sound detection device in this embodiment.

[0018] When detecting heart sounds with the heart sound detection device described above, as shown in Figure 2, the detection range (hereinafter also referred to as the detection frequency band) includes biological noise such as pulsation and respiratory sounds. Furthermore, according to the inventors' studies, in a heart sound detection device in which the sensor unit 10 is placed within the sheet unit 20 as in this embodiment, it has been confirmed that the detection frequency band may include the resonant frequency f1 of the sensor unit 10 and the resonant frequency f2 of the sheet unit 20, as shown in Figure 3. The inventors' studies have also confirmed that when the resonant frequency f1 of the sensor unit 10 or the resonant frequency f2 of the sheet unit 20 is included within the detection frequency band, biological noise is amplified by these resonant frequencies. In this case, the signal-to-noise ratio (SNR), which is the ratio of the detected signal to the noise, becomes smaller, and the detection accuracy decreases.

[0019] Therefore, in this embodiment, as shown in Figure 4, the sensor unit 10 and the sheet unit 20 are configured such that the resonant frequency f1 of the sensor unit 10 and the resonant frequency f2 of the sheet unit 20 are different from the detection frequency band.

[0020] It should be noted that the human heart rate, while varying from person to person, is generally reported to be between 30 and 35 Hz. Therefore, the detection frequency band is set to include the range of 30 to 35 Hz. In this embodiment, the upper limit fmax and lower limit fmin of the detection frequency band are set as follows. Specifically, it has been reported that the human body generally generates a heart trajectory with a large amplitude of approximately 15 to 25 Hz. Therefore, the lower limit fmin of the detection frequency band is set to 25 Hz to reduce noise caused by the heart trajectory. Furthermore, it is assumed that the sensor element 11, etc., is supplied with a power supply voltage of 50 Hz or 60 Hz. Therefore, the upper limit fmax of the detection frequency band is set to 50 Hz to reduce the influence of noise caused by the power supply voltage. In other words, the detection frequency band of this embodiment is set to be between 25 Hz and 50 Hz. In this embodiment, the resonance frequency f1 of the sensor unit 10 is greater than the upper limit fmax of 50 Hz in the detection frequency band, and the resonance frequency f2 of the sheet unit 20 is less than the lower limit fmin of 25 Hz in the detection frequency band.

[0021] Next, we will explain the resonant frequency f1 of the sensor unit 10 and the resonant frequency f2 of the sheet unit 20. First, a typical resonant frequency f is given by the following equation 1, where m is the mass and k is the spring constant.

[0022]

number

[0023] Here, the sheet portion 20 refers to the portion located above or below the sensor portion 10. In other words, the sheet portion 20 here refers to the portion surrounded by the virtual line A that passes through the side surface 10c of the sensor portion 10 and extends along the normal direction to the surface direction of the support portion 22. Further in other words, the sheet portion 20 here refers to the portion of the sheet portion 20 that overlaps when the sensor portion 10 is projected from the skin 21 side toward the support portion 22 across the sensor portion 10, and the portion that overlaps when the sensor portion 10 is projected from the support portion 22 side toward the skin 21 side across the sensor portion 10. And the sheet portion 20 has the skin 21 and the support portion 22 as described above, but the skin 21 and the support portion 22 are made sufficiently thin with respect to the inner member 23. For this reason, the mass m3 and the spring constant k3 of the sheet portion 20 are dominated by the influence of the inner member 23, and the influence of the skin 21 and the support portion 22 can be ignored. Therefore, the mass m3 and the spring constant k3 of the sheet portion 20 in the present embodiment are the mass m3 and the spring constant k3 in the inner member 23.

[0024] First, the sensor element 11 of the present embodiment is composed of a thin-film piezoelectric element, and for example, the mass m1 is set to 1 to 100 μg. Also, the housing 12 is composed of an acrylic resin or metal, and for example, the mass m2 is set to 74 g. The inner member 23 in the sheet portion 20 is composed of urethane or the like, and for example, the mass m3 is set to 100 g. That is, the mass of the sensor element 11 is made sufficiently small compared to the housing 12 and the sheet portion 20. For this reason, m1 << m2 and m1 << m3. In other words, the materials of the sensor element 11, the housing 12, and the sheet portion 20 (that is, the inner member 23) are selected so as to satisfy m1 << m2 and m1 << m3.

[0025] Furthermore, the piezoelectric film constituting the sensor element 11 has a Young's modulus of approximately 100 GPa, while the acrylic resin and metal constituting the housing 12 have a Young's modulus of approximately 1 to 100 GPa. In contrast, the urethane constituting the inner component 23 generally has a Young's modulus of approximately 10 to 1 MPa. In other words, the spring constant of the inner component 23 is sufficiently smaller than that of the sensor element 11 and the housing 12. Therefore, k1 >> k3 and k2 >> k3. To put it another way, the materials of the sensor element 11, housing 12, and sheet portion 20 (i.e., the inner component 23) are selected to satisfy k1 >> k3 and k2 >> k3.

[0026] Therefore, based on the spring-mass system in Figure 5, the resonant frequency f1 of the sensor unit 10 is given by the following equation 2. Furthermore, the resonant frequency f2 of the sheet unit 20 is given by the following equation 3.

[0027]

number

[0028]

number

[0029] First, we will explain the configuration for making the resonant frequency f1 of the sensor unit 10 greater than the upper limit of the detection frequency band fmax. The resonant frequency f1 of the sensor unit 10 is given by equation 2 as shown above. Therefore, in order to increase the resonant frequency f1, the mass m1 should be decreased or the spring constant k1 should be increased.

[0030] For example, to reduce the mass m1, since the sensor element 11 is a piezoelectric element, the mass m1 can be reduced by thinning the piezoelectric element or by selecting a lighter material for the piezoelectric element. To increase the spring constant k1, a harder material can be selected for the piezoelectric element. When increasing the spring constant k1 by selecting the material for the piezoelectric element, for example, the spring constant k1 can be increased by sandwiching the piezoelectric element between metal plates that are harder than the piezoelectric element.

[0031] In this embodiment, as described above, the upper limit fmax in the detection frequency band is set to 50 Hz. Therefore, the sensor unit 10 is formed such that the resonant frequency f1 satisfies the following equation 4.

[0032]

number

[0033] For example, to increase the mass m2, the material of the housing 12 can be changed to increase the mass m2. Alternatively, to increase the mass m2, the housing 12 may be equipped with another weight 13, as shown in Figure 6A. In this case, the weight 13 may be divided into multiple parts, as shown in Figure 6B, or it may be placed on the side surface 10c of the housing 12, as shown in Figure 6C. The weight 13 may be made of materials such as stainless steel or brass. When the weight 13 is placed in the housing 12, the part including the weight 13 becomes the sensor section 10.

[0034] To increase the mass m3, for example, the density of the enclosed member 23 located below the sensor part 10 can be increased. For example, as shown in Figure 7A, if the portion of the enclosed member 23 located between the sensor part 10 and the support part 22 is designated as the first member 23a, and the portion different from the first member 23a is designated as the second member 23b, then the density of the first member 23a should be greater than the density of the second member 23b. The enclosed member 23 located between the sensor part 10 and the support part 22 can also be described as the portion of the enclosed member 23 that overlaps when the sensor part 10 is projected from the surface 21 side.

[0035] In this case, as shown in Figure 7B, the side surface 10c of the sensor portion 10 may also be covered by the first member 23a. Furthermore, as shown in Figure 7C, the first member 23a may be placed only on the support portion 22 side, and the second member 23b may be placed between the first member 23a and the sensor portion 10. In this case, as shown in Figure 7D, the first member 23a may be provided in sections. Furthermore, as shown in Figure 7E, the first member 23a may be stacked in layers.

[0036] To reduce the spring constant k3, a softer material can be selected for the internal member 23, thereby reducing the spring constant k1. Furthermore, the spring constant k3 can be expressed as E / (t), where t is the thickness of the internal member 23 and E is its Young's modulus. 1 / 2 It is proportional to this. For this reason, the resonant frequency f2 of the sheet portion 20 is also shown by the following equation 5. In this embodiment, the thickness of the enclosed member 23 is the length between the sensor portion 10 and the support portion 22, and is the length along the projection direction when projecting the sensor portion 10 from the surface 21 side.

[0037]

number

[0038]

number

[0039] Therefore, more specifically, it is preferable that the configuration of the sheet portion 20 be adjusted so that the resonant frequency f2 obtained by the above formula 6 is less than or equal to the lower limit of the detection frequency band fmin. More specifically, in this embodiment, the lower limit of the detection frequency band fmin is set to 25 Hz. For this reason, it is preferable that the configuration of the sheet portion 20 be adjusted so that the resonant frequency f2 satisfies the following formula 7.

[0040]

number

[0041] To reduce Young's modulus E, for example, in the configurations shown in Figures 7A to 7E above, the Young's modulus of the first member 23a should be smaller than that of the second member 23b.

[0042] Furthermore, if the thickness t is to be increased, the thickness t can be increased by making the storage portion 12a of the housing 12 smaller, as shown in Figure 9.

[0043] According to the embodiment described above, the sensor unit 10 and the sheet unit 20 are configured such that their resonant frequencies f1 and f2 are different from the detection frequency band. Therefore, amplification of biological noise in the detection frequency band can be suppressed, and a decrease in detection accuracy can be suppressed.

[0044] (1) In this embodiment, the resonance frequency f1 of the sensor unit 10 is set to be greater than the upper limit fmax of the detection frequency band, and the resonance frequency f2 of the sheet unit 20 is set to be less than the lower limit fmin of the detection frequency band. As a result, the resonance frequencies f1 and f2 are at frequencies different from the detection frequency band, which can suppress a decrease in detection accuracy.

[0045] (2) In this embodiment, the resonance frequency f2 of the sheet portion 20, as shown in the above formula 6, is set to be smaller than the lower limit of the detection frequency band fmin. Therefore, it is possible to suppress the decrease in detection accuracy that occurs when the resonance frequency f2 is at a frequency different from the detection frequency band.

[0046] (3) In this embodiment, the sheet portion 20 is configured to satisfy the above equation 7. Therefore, noise due to the influence of the core trajectory can be reduced, and a decrease in detection accuracy can be suppressed.

[0047] (4) In this embodiment, if the Young's modulus of the sheet portion 20 is reduced to reduce the resonant frequency f2, the configuration of the sensor portion 10 does not need to be changed. Also, if the thickness t of the sheet portion 20 is increased to reduce the resonant frequency f2, the configuration of the sensor element 11 does not need to be changed. Furthermore, if the mass m3 is increased by changing the configuration of the encasing member 23, the configuration of the sensor portion 10 does not need to be changed. For this reason, the same sensor portion 10 as in the conventional design can be used.

[0048] (5) In this embodiment, if the mass m2 of the sensor unit 10 is increased to decrease the resonant frequency f2, the configuration of the sheet unit 20 does not need to be changed. For this reason, the same sheet unit 20 as in the conventional model can be used.

[0049] (6) In this embodiment, if the mass m2 of the sensor unit 10 is to be increased, the mass m2 can be easily increased by adding a weight 13. In this case, by using stainless steel or brass as the weight 13, it is not necessary to use special materials and the complexity of the structure can be suppressed.

[0050] (Second Embodiment) A second embodiment will now be described. This embodiment is a modification of the first embodiment in which the resonant frequency f2 of the sheet portion 20 is changed. Other aspects are the same as in the first embodiment, so a detailed explanation will be omitted here.

[0051] In this embodiment, as shown in Figure 10, the resonant frequency f2 of the sheet portion 20 is also made greater than the upper limit of the detection frequency band fmax. In other words, the sheet portion 20 has a resonant frequency f2, shown in the above equation 6, that is greater than the upper limit of the detection frequency band fmax. In this embodiment, since the upper limit of the detection frequency band fmax is 50 Hz, the sheet portion 20 is formed to satisfy the following equation 8.

[0052]

number

[0053] To reduce the mass m2, the material of the housing 12 can be changed to reduce the mass m2. Alternatively, the sensor unit 10 can be made smaller and lighter.

[0054] To reduce the mass m3, in the configuration shown in Figures 7A to 7D above, the density of the first member 23a should be less than the density of the second member 23b.

[0055] To increase Young's modulus E, in the configuration shown in Figures 7A to 7D above, the Young's modulus of the first member 23a should be greater than that of the second member 23b.

[0056] Furthermore, as shown in Figure 11, if the thickness t is to be reduced, the storage portion 12a of the housing 12 can be made larger to reduce the thickness t.

[0057] According to the embodiment described above, the sensor unit 10 and the sheet unit 20 are configured such that their resonant frequencies f1 and f2 are different from the detection frequency band. Therefore, the same effects as those of the first embodiment can be obtained.

[0058] (1) In this embodiment, the resonance frequencies f1 and f2 of the sensor unit 10 and the sheet unit 20 are set to be greater than the upper limit of the detection frequency band fmax. In this way, both the resonance frequencies f1 and f2 may be set to be greater than the upper limit of the detection frequency band fmax.

[0059] (2) In this embodiment, the resonance frequency f2 of the sheet portion 20, as shown in the above formula 6, is set to be greater than the upper limit of the detection frequency band fmax. Therefore, it is possible to suppress the decrease in detection accuracy that occurs when the resonance frequency f2 is a different frequency from the detection frequency band.

[0060] (3) In this embodiment, the sheet portion 20 is configured to satisfy the above equation 8. Therefore, noise due to the influence of the power supply voltage can be reduced, and a decrease in detection accuracy can be suppressed.

[0061] (4) In this embodiment, if the Young's modulus of the sheet portion 20 is increased to increase the resonant frequency f2, the configuration of the sensor portion 10 does not need to be changed. Also, if the thickness t of the sheet portion 20 is reduced to increase the resonant frequency f2, the configuration of the sensor element 11 does not need to be changed. Furthermore, if the mass m3 is reduced by changing the configuration of the sheet portion 20, the configuration of the sensor portion 10 does not need to be changed. For this reason, the same sensor portion 10 as in the conventional can be used.

[0062] (5) In this embodiment, if the mass m2 of the sensor unit 10 is reduced to increase the resonant frequency f2, the configuration of the sheet unit 20 does not need to be changed. For this reason, the same sheet unit 20 as in the conventional model can be used.

[0063] (Third embodiment) A third embodiment will now be described. This embodiment is a modification of the second embodiment in which the resonant frequency f1 of the sensor unit 10 is changed. Other aspects are the same as in the second embodiment, so their explanation will be omitted here.

[0064] In this embodiment, as shown in Figure 12, the resonant frequency f1 of the sensor unit 10 is made smaller than the lower limit fmin of the detection frequency band, and the resonant frequency f2 of the sheet unit 20 is made larger than the upper limit fmax of the detection frequency band.

[0065] The resonant frequency f1 of the sensor unit 10 is given by equation 2 above. Therefore, in order to reduce the resonant frequency f1 of the sensor unit 10, the spring constant k1 should be reduced or the mass m1 should be increased. For example, to increase the mass m1, the material constituting the piezoelectric element should be changed to increase the mass m1. Also, to reduce the spring constant k1, the Young's modulus of the sensor element 11 should be reduced, so the material constituting the piezoelectric element should be changed to reduce the spring constant k1.

[0066] According to the embodiment described above, the sensor unit 10 and the sheet unit 20 are configured such that their resonant frequencies f1 and f2 are different from the detection frequency band. Therefore, the same effects as those of the first embodiment can be obtained.

[0067] (1) As in this embodiment, the resonance frequency f1 of the sensor unit 10 may be made smaller than the lower limit value fmin of the detection frequency band.

[0068] (Other embodiments) This disclosure is described in accordance with embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and idea of ​​this disclosure.

[0069] In the embodiments described above, a piezoelectric element was used as an example for the sensor element 11. However, the sensor element 11 may be composed of an acceleration sensor, a MEMS microphone, or the like. MEMS stands for Micro Electro Mechanical Systems.

[0070] Furthermore, in each of the above embodiments, an example was described in which one surface 10a of the sensor portion 10 is in contact with the outer layer 21. However, the sensor portion 10 may be arranged such that an internal member 23 exists between the one surface 10a and the outer layer 21. In this case, the mass m3 of the sheet portion 20 (i.e., the internal member 23) will be the portion located between the sensor portion 10 and the outer layer 21, and the portion located between the sensor portion 10 and the support portion 22.

[0071] Furthermore, in each of the above embodiments, examples were described in which the sensor element 11 is arranged inside a box-shaped housing 12. However, depending on the configuration of the sensor element 11, a part of the housing 12 may be made up of the sensor element 11. For example, one surface 10a of the sensor part 10 may be made up of the sensor element 11.

[0072] Furthermore, in each of the above embodiments, a heart sound detection device was used as an example to describe the biological sound detection device. However, the biological sound detection device may be, for example, a lung sound detection device that detects lung sounds as biological sounds, or a detection device that detects the cardiac trajectory as biological sounds. In this case, the detection frequency band is appropriately set to include the frequency of the biological sound to be detected. [Explanation of symbols]

[0073] 10 Sensor elements 11 Sensor section 20 Sheet section f1 resonance frequency f2 resonance frequency

Claims

1. A biological sound detection device for detecting biological sounds of the human body, A sensor unit (10) having a sensor element (11) that outputs a detection signal corresponding to the biological sound, and a housing (12) that houses the sensor element, The device comprises a sensor unit located inside and a sheet unit (20) that comes into contact with the human body, The sensor unit and the sheet unit are configured such that their resonant frequencies (f1, f2) are different from those of the detection frequency band, with respect to a predetermined range of detection frequency bands that include the frequencies of the biological sounds. The resonant frequency (f1) of the sensor section is given by the value shown in the following formula 1, where m1 is the mass of the sensor element and k1 is the spring constant of the sensor element. The sheet portion comprises a surface (21) that comes into contact with the human body, and an internal member (23) positioned on the opposite side of the surface from the human body, covering at least a portion of the sensor portion. The resonant frequency (f2) of the sheet portion of the biosound detection device is given by the value shown in the following formula 2, where m2 is the mass of the housing, m3 is the mass of the portion of the enclosed member that overlaps when the sensor portion is projected from the surface side and when the sensor portion overlaps when projected from the opposite side of the surface side, and k3 is the spring constant. [Math 1] [Math 2]

2. The sensor unit is configured such that the resonant frequency (f1) of the sensor unit is greater than the upper limit of the detection frequency band. The biosound detection device according to claim 1, wherein the resonance frequency (f2) of the sheet portion is smaller than the lower limit of the detection frequency band.

3. The sensor unit is configured such that the resonant frequency (f1) of the sensor unit is greater than the upper limit of the detection frequency band. The biosound detection device according to claim 1, wherein the resonant frequency (f2) of the sheet portion is greater than the upper limit of the detection frequency band.

4. The sensor unit is configured such that the resonant frequency (f1) of the sensor unit is smaller than the lower limit of the detection frequency band. The biosound detection device according to claim 1, wherein the resonant frequency (f2) of the sheet portion is greater than the upper limit of the detection frequency band.

5. A biological sound detection device for detecting biological sounds of the human body, A sensor unit (10) having a sensor element (11) that outputs a detection signal corresponding to the biological sound, and a housing (12) that houses the sensor element, The device comprises a sensor unit located inside and a sheet unit (20) that comes into contact with the human body, The sensor unit and the sheet unit are configured such that their resonant frequencies (f1, f2) are different from those of the detection frequency band, with respect to a predetermined range of detection frequency bands that include the frequencies of the biological sounds. The resonant frequency (f1) of the sensor section is given by the value shown in the following equation 3, where m1 is the mass of the sensor element and k1 is the spring constant of the sensor element. The sheet portion comprises a surface (21) that comes into contact with the human body, and an internal member (23) positioned on the opposite side of the surface from the human body, covering at least a portion of the sensor portion. The resonant frequency (f2) of the sheet portion is given by the following formula 4, where m2 is the mass of the housing, m3 is the mass of the portion of the enclosed member that overlaps when the sensor portion is projected from the surface side and when the sensor portion overlaps when the sensor portion is projected from the opposite side of the surface side, and k3 is the spring constant, and t is the thickness of the enclosed member along the projection direction of the portion of the enclosed member that overlaps when the sensor portion is projected from the surface side and when the sensor portion overlaps when the sensor portion is projected from the opposite side of the surface side, and E is the Young's modulus, then k3 = E / (t) 1 / 2, and the value is given by the following formula 4 for the biosound detection device. [Math 3] [Math 4]

6. The aforementioned sheet portion is The biological sound detection device according to claim 5, wherein the lower limit of the detection frequency band is fmin, and the device is configured to satisfy the following formula 5. [Math 5]

7. The aforementioned biological sound is a heart sound. The biosound detection device according to claim 6, wherein the sheet portion is configured to satisfy the following formula 6. [Math 6]

8. The biosound detection device according to claim 6 or 7, wherein the sensor unit is a weighted body (13) attached to the housing.

9. The biosound detection device according to claim 8, wherein the weight is made of stainless steel or brass.

10. The aforementioned sheet portion is The biological sound detection device according to claim 5, wherein the upper limit of the detection frequency band is fmax, and the device is configured to satisfy the following formula 7. [Number 7]

11. The aforementioned biological sound is a heart sound. The biosound detection device according to claim 10, wherein the sheet portion is configured to satisfy the following formula 8. 【Number 8】

12. The biosound detection device according to claim 10 or 11, wherein the sheet portion has a portion of the enclosed member that overlaps when the sensor portion is projected from the skin side, and a portion that overlaps when the sensor portion is projected from the opposite side of the skin side, in which the portion has a higher Young's modulus than the portion that overlaps when the sensor portion is projected.

Images