JP2018068476A - Pulsation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulsation detector capable of easily measuring heart sound and pulse even in a state of moving relative to various sites of a subject.SOLUTION: A pulsation detector SNSR includes: a microphone 2 receiving sound pressure and converting it into an electric signal; a casing 1 to which the microphone is attached; and an air chamber 3 formed at a front side of the casing with it communicated with a sound pressure input surface of the microphone. The air chamber includes: a vibrating membrane 31 that is fixed to a peripheral edge part of the casing so as to include the microphone and whose outer surface can come into contact with a surface of a subject; and support members 32-34 that three-dimensionally support the vibrating membrane with their engaged with the inner surface of the vibrating membrane so as to form an internal space, and form different-magnitude mechanical impedances against pressing force to the subject, at different sites of the vibrating film.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pulsation detection device, and more particularly to a technique that is effective when applied to a device that detects pulsation such as a heartbeat or a pulse.

  Conventionally, in order to detect a heartbeat and a pulse wave (pulse), a method of measuring a pressure in a blood vessel with a pulsation detection device using a microphone has been widely used. As a pulsation detecting device represented by a heart sound microphone device, there are an air conduction type and a direct conduction type (acceleration type, perrotte type).

  The air conduction type employs an electrodynamic type such as a small dynamic speaker in which a coil is set in a magnetic field of a permanent magnet as a sound pressure / electrical conversion for converting a sound pressure into an electric signal, or a diaphragm In some cases, an electrostatic type such as a condenser microphone having a back electrode is used, and in either case, an air chamber is interposed between the subject surface and the microphone to detect a pressure change directly above the artery. The air conduction type is an improved version of the drive detection device, in which a vibration membrane such as silicon rubber is provided on the front surface of the microphone, where it touches the subject, and a projection is provided on the vibration membrane so that the microphone is positioned directly above the artery. There are things.

  In the direct conduction type, for example, a piezoelectric or electrostrictive element is used as vibration / electrical conversion for converting vibration into an electric signal, and the piezoelectric element is piezoelectrically supported on a weight whose ends are elastically supported by a support spring such as phosphor bronze. An acceleration type with an element or a piezoelectric element or conductive coil is used as vibration / electrical conversion, and a small perotte (contact) is placed in a rubber cylindrical peripheral support via a damper rubber. Some of them employ a Perrotte type that is connected to a support spring and a coil provided at the upper end thereof is set in a magnetic field of a permanent magnet. In the direct conduction type, a case or a perotte is pressed directly against the skin just above the artery to detect vibration due to pressure fluctuations in the blood vessel. In general, a direct conduction type Perotte type pulsation detecting device is pressure-bonded to the body surface with a weight of nearly 300 g. The acceleration type is small and light (30 g) and can be fixed to the human body with a plaster.

  In addition, as described in Patent Documents 1 and 2 as a direct conduction type pulsation detection device, a bulk-like vibration transmission member made of an elastic body such as silicon rubber is arranged as a vibration transmission member on the front surface of the microphone, A structure is disclosed in which sensitivity is improved by covering the peripheral side of the microphone and the vibration transmitting member with a damping member.

Japanese Patent Laid-Open No. 2014-45717 JP, 2014-45918, A

  The above pulsation detection device requires very little power for sound pressure / electrical conversion and vibration / electrical conversion, and can be configured with a simple structure, so it is most suitable for pulsation detection devices in terms of low power consumption and low cost. Has suitable characteristics.

  However, the conventional pulsation detection device is an air conduction type in which the shape of the opening or the vibrating membrane in contact with the surface of the subject is a flat surface or a partial protrusion on the flat surface, and a curved surface such as an arm or a finger. If it is used on an uneven part, it can touch only a part. In this regard, according to the inventor's investigation, it is considered that the vibration film disposed in front of the air chamber is inferior in flexibility because a relatively large tension is applied. In addition, as in Patent Documents 1 and 2, the structure in which the bulk-shaped vibration transmission member is arranged on the front surface of the microphone does not require a tensioned vibration film, but the bulk-shaped vibration transmission member is similarly used for the subject. It is still difficult to deform flexibly along curved surfaces and irregularities. The inferior flexibility of the contact portion with the subject includes a problem that the pulsation cannot be detected by bringing the microphone as close to the blood vessel as possible. In addition, since the sensitivity of the microphone is greatly related to the area of the diaphragm, particularly the contact area with the subject, it is natural that the diaphragm cannot be simply reduced in size and brought into contact with the subject. Even if the vibrating membrane is used with a large size, only a part of the vibrating membrane can be brought into contact with the subject, and there is a problem that the detection sensitivity of pulsation cannot be improved as expected.

  The structure and size of such a conventional air conduction type pulsation detection device has made it extremely inconvenient to use because it has prevented the blood vessel immediately below the surface of the subject from being stably approached as much as possible. Acceleration-type and Perrotte-type pulsation detection devices are also difficult to detect in terms of structure and operation because it is difficult to press the contact against the convex and concave portions of the subject and keep it in the correct position and keep it constantly pressed. The decrease in sensitivity and inconvenience were the same as above. In addition, it is necessary for the user not to move the body at the time of detection, so that the pulsation detecting device stays in a normal position.

  An object of the present invention is to provide a pulsation detecting device that can easily measure heart sounds and pulses even when moving with respect to various parts of a subject.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application. Reference numerals in the drawings referred to with parentheses in the description of this section merely exemplify what are included in the concept of the components to which the reference numerals are attached.

  [1] That is, the pulsation detecting device (SNSR) communicates with a microphone (2) that receives sound pressure and converts it into an electrical signal, a casing (1) to which the microphone is attached, and a sound pressure input surface of the microphone. And an air chamber (3, 4) formed on the front side of the casing. The air chamber is fixed to the peripheral portion of the casing so as to contain the microphone, and has a vibrating membrane (31, 41) that allows the outer surface to be in contact with the surface of the subject (5); The vibration membrane is three-dimensionally supported so as to form an internal space (30, 40) by engaging with the inner surface, and different mechanical impedances are formed at different parts of the vibration membrane against the pressing force on the subject. And supporting members (32 to 34, 42).

  According to the above, while pressing the vibrating membrane supported by the support member against the surface in the vicinity of the measurement site of the subject, the portion of the air chamber just above the bone, muscle, or tendon removed from the artery inside the subject (MIP2) Resists the pressing force by a large mechanical impedance, and the part of the air chamber (MIP1) immediately above the artery resists the pressing force by a small mechanical impedance, and determines the pressing position of the diaphragm relative to the measurement site. . The mechanical impedance is a ratio of the displacement speed to the applied force. If the force is the same, the mechanical impedance increases as the displacement speed decreases. In the portion where the mechanical impedance is large, the vibrating membrane is supported without being greatly displaced with respect to the pressing force, and in the portion where the mechanical impedance is small, the vibrating membrane is displaced following the pulsation. In a state where the vibrating membrane is pressed against the surface near the measurement site of the subject, a portion having a large mechanical impedance immediately above a bone or muscle and a portion having a small mechanical impedance directly above an artery or the like are separated. As a result, even if the diaphragm is strongly pressed against the subject, the mechanical impedance directly above the artery can maintain a small value, and the diaphragm of that part can be brought close to the artery, so that the part with a small mechanical impedance is pulsated. Periodic changes in sound pressure due to a vibrating membrane that follows and displaces can be detected with high sensitivity. And since the support member three-dimensionally supports the diaphragm so as to engage with the inner surface of the diaphragm to form an inner space, the inner space prevents a small mechanical impedance part from vibrating greatly. Absent. Therefore, the pressure change in the blood vessel is accurately transmitted to the vibrating membrane without being disturbed by the surrounding muscles and tendons, and it is difficult to be influenced by noise from external sounds and vibrations, and it is possible to detect the optimal heart sound and pulse. become.

  [2] It is preferable that the casing is provided with a pressure adjusting hole (12) having a predetermined inner diameter and length that allows the internal space of the air chamber to communicate with the atmospheric pressure. The microphone is an air conduction type, and the sound pressure / electrical conversion may be of an electrodynamic type or of an electrostatic type. The microphone needs a measurement frequency band that is low enough to measure a periodic waveform of a pulse such as a pulse. Therefore, it is possible to adjust the atmospheric pressure and the lower limit frequency by the inner diameter and the length of the atmospheric pressure adjusting hole which is a small hole communicating with the outside air through the internal space of the air chamber.

  [3] As one typical form of the pulsation detecting device (FIGS. 1, 2, and 7), the support member is a support column (32, 33, 34) provided upright at an arbitrary position of the casing. Yes, the mechanical impedance of the diaphragm in the part not in contact with the support (MIP1) is made smaller than the mechanical impedance of the diaphragm in the part in contact with the support (MIP2).

  According to this, the magnitude of the mechanical impedance is determined in advance between the portion of the diaphragm that is in contact with the support and the portion of the diaphragm that is not in contact with the support. Therefore, when the vibrating membrane supported by the support member is pressed against the surface near the measurement site of the subject, the vibrating membrane is stabilized by positioning the strut directly above the bone, muscle or tendon outside the artery inside the subject. The part with a small mechanical impedance arranged just above the artery is displaced by following the pulsation. Since the diaphragm with a large mechanical impedance is supported by the support, the position of the diaphragm, muscle or tendon can be searched while pressing the diaphragm against the surface of the subject during measurement. It can be easily determined.

  [4] In the above, the support column is preferably formed of a viscoelastic body or a rubber elastic body. When the vibrating membrane is pressed against the surface of the subject, the damper effect of the support can be expected.

  [5] The vibrating membrane is fixed to the peripheral portion of the casing so as to contain the microphone and forms an internal space so that the vibrating membrane can vibrate. Constructing the vibrating membrane from a rubber elastic body that is more flexible than the support column contributes to further improvement in detection sensitivity.

  [6] In the above, a plurality of struts having different lengths may be employed as the struts, and a part of the outer surface of the vibrating membrane that can be brought into contact with the subject may be supported and projected by a strut longer than the others. According to this, even if a projecting portion having a large mechanical impedance is strongly pressed against the subject, it is possible to mitigate an increase in the reaction force pair acting on a portion having a small mechanical impedance. This increases the stability when positioning by pressing and contributes to further improvement in detection sensitivity.

  [7] In the above, a three-dimensional shape having a concave central portion may be adopted for the vibrating membrane as a shape for projecting a part of the outer surface of the vibrating membrane.

  [8] In the same manner as described above, a three-dimensional shape having a convex center part may be adopted as the shape for projecting a part of the outer surface of the diaphragm.

  [9] As another typical form of the pulsation detecting device (FIG. 9, FIG. 10, FIG. 12, FIG. 13), the support member is randomly formed by winding a continuous filament of fibers made of thermoplastic elastomer. The mechanical structure of the vibrating membrane in the portion (MIP1) having a small force against the pressing force on the subject is a portion (MIP2) having a large force against the pressing force on the subject. To be smaller than the mechanical impedance of the vibrating membrane.

  According to this, the magnitude of the mechanical impedance generated in different parts of the vibration film is not determined in advance, but is determined in a state where the vibration film is actually pressed against the surface of the subject. That is, the joint structure is greatly compressed at the part of the air chamber just above the bone, muscle, or tendon outside the artery inside the subject to generate a large mechanical impedance, and at the part of the air chamber just above the artery, the joint structure is A small mechanical impedance is produced without compression to the left. Thus, the magnitude of the mechanical impedance of the air chamber can be dynamically determined according to the location where the vibration membrane is actually pressed. Therefore, it is possible to easily arrange a small mechanical impedance region immediately above or near the artery while conveniently adjusting to a complicated surface configuration of the subject or a complicated internal arrangement such as a bone part or an artery of the subject.

  [10] The continuous filaments have, for example, a wire diameter of 0.1 mm to 3.0 mm.

  [11] In the above, the vibration film is preferably formed of a rubber elastic body. The vibrating membrane is fixed to the peripheral portion of the casing so as to contain the microphone and is formed to be able to vibrate by forming an internal space. Therefore, the vibrating membrane itself does not require special flexibility. Is made of a rubber elastic body, which contributes to further improvement in detection sensitivity.

  [12] In the above, the thickness dimension of the bonding structure in the front and back direction of the vibration membrane is partially different, and a part of the outer surface that can be brought into contact with the subject is the thickness dimension of the bonding structure. The vibrating membrane may be formed so as to protrude accordingly. According to this, even if a projecting portion having a large mechanical impedance is strongly pressed against the subject, the reaction force acting on the portion having a small mechanical impedance can be mitigated, and as a result, a vibrating membrane can be applied to the subject. Stability at the time of pressing and positioning increases, which contributes to further improvement in detection sensitivity.

  [13] A three-dimensional shape having a concave central portion may be adopted as the shape for projecting a part of the outer surface of the diaphragm.

  [14] In the same manner as described above, a three-dimensional shape having a convex center part may be adopted as the shape for projecting a part of the outer surface of the diaphragm.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, it is possible to provide a pulsation detecting device that can easily measure heart sounds and pulses even when moving with respect to various parts of the subject.

FIG. 1 is a cross-sectional view showing a first example of a pulsation detecting device according to the present invention. 2 is a partially cutaway perspective view of the pulsation detecting device shown in FIG. FIG. 3 is a bottom view of the pulsation detecting device shown in FIG. FIG. 4 is a side view of the pulsation detecting device shown in FIG. FIG. 5 is a cross-sectional view showing an example of an air pressure adjusting hole of the pulsation detecting device shown in FIG. FIG. 6 is an explanatory diagram showing an example of use of the pulsation detecting device shown in FIG. FIG. 7 is a cross-sectional view showing a second example of the pulsation detecting device according to the present invention. FIG. 8 is an explanatory view showing an example of use of the pulsation detecting device of FIG. FIG. 9 is a cross-sectional view showing a third example of the pulsation detecting device according to the present invention. FIG. 10 is a partially cutaway perspective view of the pulsation detecting device shown in FIG. FIG. 11 is an explanatory view showing an example of use of the pulsation detecting device of FIG. FIG. 12 is a transverse sectional view showing a fourth example of the pulsation detecting device according to the present invention. FIG. 13 is a cross-sectional view showing a fifth example of the pulsation detecting device according to the present invention. FIG. 14 is a waveform diagram illustrating a detected waveform from the wrist by the pulsation detecting device according to the invention. FIG. 15 is a waveform diagram illustrating a waveform detected from the wrist by a conventional heart sound sensor. FIG. 16 is a waveform diagram illustrating a detected waveform from the tip of the fingertip by the pulsation detecting device according to the invention. FIG. 17 is a waveform diagram illustrating a detection waveform from the tip of a fingertip by a conventional heart sound sensor. FIG. 18 is an explanatory view illustrating a state in which the pulsation detecting device of the present invention is incorporated in the seat surface of the chair. FIG. 19 is a waveform diagram illustrating a detection waveform from the buttocks by the pulsation detection device according to the invention. FIG. 20 is a waveform diagram illustrating a detection waveform from the buttocks by a conventional heart sound sensor.

  1 and 2 show a first example of a pulsation detecting device according to the present invention. The pulsation detection device SNSR shown in the figure is a device that detects pulsations such as heartbeats and pulsations.

  The pulsation detection device SNSR is formed on the front side of the casing 1 in communication with the microphone 2 that receives sound pressure and converts it into an electrical signal, the casing 1 to which the microphone 2 is attached, and the sound pressure input surface of the microphone 2. And an air chamber 3. The air chamber 3 is fixed to the peripheral portion of the casing 1 so as to contain the microphone 2, and engages with the vibration film 31 that allows the outer surface to come into contact with the surface of the subject 5 and the inner surface of the vibration film. Support members 32 to 34 that three-dimensionally support the vibrating membrane 31 so as to form the internal space 30 and form different mechanical impedances at different portions MIP1 and MIP2 of the vibrating membrane 31 against the pressing force on the subject. And having.

  In the example of FIG. 1, the support members are support columns 32, 33, 34 erected at an arbitrary position of the casing, and the mechanical impedance MIP 1 of the vibrating membrane 31 in a portion not in contact with the support columns 32, 33, 34 is the support column 32. , 33, 34 is made smaller than the mechanical impedance MIP <b> 2 of the vibrating membrane 31 at the part in contact with it. In the example of FIG. 1, the support column 33 at the center is the longest, and as is clear from FIGS. 3 and 4, the vibration film 31 has a mountain-shaped three-dimensional shape, and the center is projected. As apparent from FIG. 2, the internal space 30 communicates without being divided by the support 33. The vibration film 31 may be formed of silicon rubber or an appropriate elastomer. The support columns 32, 33, and 34 are preferably formed of a viscoelastic body or a rubber elastic body. This is because when the vibrating membrane is pressed against the surface of the subject 5, the damper effect of the columns 32, 33, and 34 can be expected. The vibrating membrane 31 is fixed to the peripheral portion of the casing 1 so as to enclose the microphone 2 and forms an internal space so as to be able to vibrate. Therefore, the vibrating membrane 31 itself does not require special flexibility. It is desirable that the vibration film 31 is made of a rubber elastic body that is more flexible than the support columns 32, 33, and 34, or is made thin.

  The casing 1 has an atmospheric pressure adjusting hole 12 having a predetermined inner diameter and length that allows the internal space 30 of the air chamber 3 to communicate with atmospheric pressure. That is, the air chamber 3 is sealed except for the path of the atmospheric pressure adjustment hole 12. The air adjustment hole 12 may be formed vertically as illustrated in FIG. 1, or when the required length cannot be obtained by the vertical formation alone, the vertical hole and the horizontal hole may be combined as shown in FIG. That's fine.

  The microphone 2 is of an air conduction type, and the sound pressure / electrical conversion may be of a known electrodynamic type or of an electrostatic type. In consideration of measuring the periodic waveform of the pulse, the microphone 2 requires a sufficiently low frequency measurement frequency band, and the lower limit frequency is set to 0.5 Hz, for example.

  The casing 1 accommodates the microphone 2 and at the same time forms a part of a structure for constituting the air chamber 3 together with the vibration film 31. The atmospheric pressure adjusting hole 12 is a small hole for adjusting the atmospheric pressure of the internal space 30 of the air chamber 3 and adjusting the lower limit of the measurement frequency, and communicates with the outside air. The atmospheric pressure adjusting hole 12 increases the lower limit frequency as the hole is larger and shorter. The vibration film 31 is fixed to the outer peripheral edge of the casing 1. With respect to the fixed state of the vibration film 31, the vibration film 31 that is not in contact with the pillars 32, 33, 34 is easily displaced by the reaction force from the subject in the portion. However, it is fixed to the casing so that excessive tension is not applied so that it can be bent. The vibration film 31 can be formed integrally with the casing 1.

  The air chamber 3 is surrounded by the casing 1 and the vibration film 31 for transmitting the pressure change in the blood vessel captured by the vibration film 31 to the microphone 2 which is a sound pressure / electrical converter as the pressure change of the air. A space (internal space 30) is formed. The internal space 30 is a three-dimensional space, and is formed so that the central portion protrudes as described above, and its shape is determined according to the shape of the vibrating membrane 31 supported by the support columns 32, 33, and 34.

  The vibrating membrane 31 directly contacts the surface of the subject 5 to detect a pressure change in the artery 51. The pressure change propagates to the internal space 30 through the vibrating membrane 31, and the sound pressure / It is transmitted to the microphone 2 of the electric converter. The three-dimensional structure of the vibrating membrane 31 can increase the effective area of the membrane related to the efficiency of sound pressure and electrical conversion, and it can be easily and smoothly adjusted even if there are irregularities in any shape of any part of the body, for example It is because it can touch.

  As described above, the air chamber 3 is divided into two different mechanical impedance regions MIP1 and MIP2, and the respective regions MIP1 and MIP2 play different roles. Among two different mechanical impedance regions, a membrane region (hereinafter also referred to as a first mechanical impedance region) MIP1 having a small mechanical impedance value is a conventional vibrating membrane for detecting a pressure change in a blood vessel. One region having a large mechanical impedance value (hereinafter also referred to as a second mechanical impedance region) MIP2 used as a portion functions as a portion for holding the vibration film 31 of the first mechanical impedance region MIP1.

  Of the two different mechanical impedance regions of the diaphragm 31, the mechanical impedance value of the first mechanical impedance region MIP1 is important in determining the sensitivity of the pulsation detecting device as a sensor. Since the vibration film 31 is arranged so as to detect a pressure change in the vicinity of the blood vessel, it is preferably a value close to the mechanical impedance in the vicinity of the blood vessel. Further, the degree of freedom of change is increased when the film is soft as much as possible without applying unnecessary tension so that the shape of the film in the first mechanical impedance region MIP1 can be freely changed according to the surface of the subject. Accordingly, it is desirable that the vibrating membrane 31 can be changed relatively freely along the curved surface even when contacting an arbitrary curved surface, and the impedance value of the first mechanical impedance region MIP1 of the vibrating membrane 31 is close to the impedance of the blood vessel. In order to make it soft, it is preferable to set it as small as possible.

  Furthermore, when the vibration film 31 is unable to match the impedance value of the blood vessel because the tension of the film in the first mechanical impedance region MIP1 changes greatly due to the force when pressed against the body of the subject, the original performance is obtained. Since there is a possibility that it will not be possible, a structure is considered in which the change in the impedance value of the first mechanical impedance region MIP1 when pressed is minimized. That is, the second mechanical impedance region MIP2 retains the shape so as not to bend the membrane of the first mechanical impedance region MIP1, and at the same time, when pressed against the surface of the subject, the first mechanical impedance region MIP1 hardly causes a change in tension. In order to support the vibrating membrane 31, the support columns 32, 33, and 34 are provided, and the supporting columns 32, 33, and 34 apply the reaction force when the vibrating membrane 31 is pressed against the surface of the subject. The nonlinear elastic function that elastically supports and the function that structurally supports the vibration film 31 are integrally formed.

  FIG. 6 shows a usage example of the pulsation detecting device. First, while pressing the vibrating membrane 31 against the surface of the subject 5 near the measurement site, the part MIP2 of the air chamber 30 just above the bone, muscle, or tendon 50 outside the artery 51 inside the subject 5 has a large mechanical impedance. The pressure position of the vibrating membrane 31 is determined with respect to the measurement site by resisting the pressing force and the portion MIP1 of the air chamber just above the artery against the pressing force by a small mechanical impedance. When the diaphragm 31 in the first mechanical impedance region MIP1 is guided to a position where the blood vessel is not pressed down too close to the artery 51, the surface of the subject just above the muscle or tendon removed from the artery 51 or the bone 50 The vibration film 31 is positioned at the measurement position by pressing while pressing in the second impedance region. At this time, the struts 32, 33, and 34 can support the vibrating membrane 31 that receives the reaction force of the pressing force directly above the muscle, tendon, or bone, and the first mechanical impedance region MIP1 in the vicinity of the artery 51. To prevent excessive force from changing the mechanical impedance. The first mechanical impedance region MIP1 retains the three-dimensional shape of the vibrating membrane 31 and functions as a soft membrane that moves according to the pressure change of the artery 50, and the second mechanical impedance region MIP2 is directly above the muscle, tendon, or bone. It functions as a non-linear spring that supports the vibrating membrane 31 that is strongly pressed against the body surface and receives the reaction. The second mechanical impedance region MIP2 is naturally larger than the mechanical impedance value of the first mechanical impedance region MIP1, and is set to a value that matches the mechanical impedance value of the portion of the subject pressing the vibrating membrane 31. desirable.

  According to the first example, the portion having a large mechanical impedance (MIP2) supports the vibrating membrane 31 without being greatly displaced with respect to the pressing force, and the portion having a small mechanical impedance (MIP1) follows the pulsation to follow the vibrating membrane. 31 is displaced. In a state where the vibrating membrane 31 is pressed against the surface of the subject 5 near the measurement site, a portion MIP2 having a large mechanical impedance directly above the bone or muscle 51 and a portion having a small mechanical impedance directly above the artery 50 (MIP1) And are separated. Thereby, even if the vibrating membrane is strongly pressed against the subject 5, the mechanical impedance immediately above the artery can be kept small, and the vibrating membrane 31 at that portion can be brought close to the artery, so that a portion with a small mechanical impedance (MIP1 ), It is possible to detect the periodic change of the sound pressure due to the vibration film 31 that is displaced following the pulsation with high sensitivity. Since the support columns 32, 33, and 34 support the diaphragm 31 in a three-dimensional manner so as to engage with the inner surface of the diaphragm 31 to form an inner space, the inner space has a large mechanical impedance portion MIP1. There is no hindrance to vibration. Therefore, the pressure change in the artery 50 is accurately transmitted to the vibrating membrane 31 without being disturbed by the surrounding muscles and tendons 51, and is not easily affected by noises caused by extraneous sounds or vibrations. Is possible. The magnitude of the mechanical impedance is determined in advance between the portion of the diaphragm 31 that is in contact with the columns 32, 33, and 34 and the portion of the diaphragm 31 that is not in contact with the columns 32, 33, and 34. Therefore, when the vibrating membrane 31 supported by the columns 32, 33, and 34 is pressed against the surface of the subject 5 near the measurement site, the column is directly above the bone, muscle, or tendon 51 removed from the artery 50 inside the subject. 32, 33, and 34 are positioned to stably support the vibrating membrane 31, and the portion MIP1 having a small mechanical impedance arranged immediately above the artery 50 is displaced following the pulsation. Since the vibration membrane of the portion MIP2 having a large mechanical impedance is supported by the columns 32, 33, and 34, the position of the bone, muscle, or tendon 51 can be searched while pressing the vibration membrane 31 against the surface of the subject 5 during measurement. Therefore, the pressing position of the vibration film 31 can be easily determined.

  FIG. 7 shows a second example of the pulsation detecting device according to the present invention. The shape of the air chamber 3 is not limited to that shown in FIGS. 1 and 2 and can be changed as appropriate. For example, when the pulsation detecting device is brought into close contact with a shape such as a finger, as shown in the example of FIG. If it is concave along the surface of the subject, it is good. As shown in the explanatory diagram of the use state in FIG. 8, if the vibrating membrane 31 is supported in a concave shape by the support columns 32, 33, 34, the reaction force from the subject 5 is received in the second mechanical impedance regions MIP2 at the two left and right positions. The pulsation detection device SNSR can be stably pressed and positioned on the subject 5 when detecting the pulsation. Since the other configuration is the same as that of the example of FIG. 1, members having the same functions are denoted by the same reference numerals, and detailed description thereof is omitted.

  9 and 10 show a third example of the pulsation detecting device according to the present invention. In the pulsation detecting device SNSR shown in the figure, the support member of the air chamber 4 is a joined structure 42 of random loops in which continuous filaments of fibers made of thermoplastic elastomer are wound. Random loops are made of thermoplastic elastomers including, for example, styrenic thermoplastic elastomers, and are formed by twisting continuous linear bodies with a fiber diameter of about 0.1 mm to 3.0 mm, and the random loops are melted together. In contact with each other, a three-dimensional joint structure 42 in a random loop is formed.

  The joint structure 42 is fixed to the edge of the casing 1 in the same manner as described above or covered with the vibration film 41 integrally formed on the edge of the casing 1 to form the air chamber 4. The joint structure 42 has nonlinear elasticity, and only the portion pressed from the outside of the vibration film 41 sinks and is displaced together with the vibration film 41. Therefore, if any part of the vibration film 41 is pressed, the vibration film 41 sinks. If the vibration film 41 is pressed against the surface of the subject 5 that is not flat, the vibration film 41 is easily deformed according to an arbitrary shape of the surface. To do. A portion that is depressed by pressing produces a larger reaction force than a portion that does not press. Considering this state as a reference, the mechanical impedance of the vibrating membrane in the first mechanical impedance region MIP1, which is a portion having a small force against the pressing force on the subject 5, is a force that resists the pressing force on the subject 5. Is smaller than the mechanical impedance of the vibrating membrane 41 in the second mechanical impedance region MIP2 which is a large portion. The vibration film 41 in the first impedance region MIP1 is displaced following the pulsation, and the vibration film 41 in the second impedance region MIP1 is hardly displaced following the pulsation, and is unnecessary for the vibration film 41 in the first impedance region MIP1. The vibration film 41 is supported on the surface of the subject 5 so as to prevent superfluous vibration from being superimposed.

  In the example of FIGS. 9 and 10, the thickness dimension of the bonding structure 42 in the front and back direction of the vibration film 41 is partially different, and a part of the outer surface that can be brought into contact with the subject 5 is the bonding structure. The vibration film 41 is formed so as to protrude in accordance with the thickness dimension of 42, and, for example, a three-dimensional shape having a concave central part is adopted for the vibration film 41. Since the other configuration is the same as that of the example of FIG. 1, members having the same functions are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the pulsation detection device SNSR of FIGS. 9 and 10, the magnitude of the mechanical impedance generated in different parts of the vibrating membrane 41 is not determined in advance, and the vibrating membrane 41 is actually pressed against the surface of the subject 5. Determined by state. For example, as illustrated in FIG. 11, the joint structure is large in a portion of the air chamber 4 (second mechanical impedance region MIP2) just above the bone, muscle, or tendon 50 that is removed from the artery 51 inside the subject 5. Compression generates a large mechanical impedance, and the joint structure 42 does not compress to the left at the portion of the air chamber 4 immediately above the artery 51 (first mechanical impedance region MIP1), and a small mechanical impedance is generated. As described above, the magnitude of the mechanical impedance of the air chamber 4 can be dynamically determined according to the place where the vibration film 41 is actually pressed. Therefore, a small mechanical impedance region can be easily arranged immediately above or in the vicinity of the artery 51 while conveniently adjusting to the complicated surface configuration of the subject 5 or a complicated internal arrangement such as the bone portion of the subject 5 or the artery 50. . In particular, by making the thickness dimension of the joint structure in the front and back directions of the vibration film partially different so that the center part of the vibration film 41 is concave, the protruding portion having a large mechanical impedance is strongly pressed against the subject 5. It is possible to mitigate an increase in reaction force acting on a portion having a small mechanical impedance even if the contact is applied. As a result, the stability when the diaphragm is pressed against the subject 5 is increased, and the detection sensitivity is further increased. Contributes to improvement.

  FIG. 12 shows a fourth example of the pulsation detecting device according to the present invention. The pulsation detecting device SNSR shown in the figure is different from FIG. 9 in that a three-dimensional shape having a convex central part is adopted for the vibrating membrane 41 as a shape for projecting a part of the outer surface of the vibrating membrane 41. FIG. 13 shows a fifth example of a pulsation detecting device according to the present invention. The pulsation detection device SNSR shown in the figure is different from FIG. 9 in that the outer surface of the vibration film 41 is planar. 12 and 13 are the same as those in the example of FIG. 9, members having the same functions are given the same reference numerals, and detailed descriptions thereof are omitted.

  Next, an experimental example in which the pulsation detecting device according to the present invention is actually used for the wrist, finger tip, and hip of a human body will be described.

  14 illustrates a detected waveform from the wrist by the pulsation detecting device according to the present invention, and FIG. 15 illustrates a detected waveform from the wrist by a conventional heart sound sensor. In each figure, the vertical axis represents the amplitude value of the pulse wave, and the horizontal axis represents time. The first half of the waveform was measured during walking, and the second half was measured at rest. The waveform measured by the pulsation detection device SNSR of the present invention clearly shows the position of the peak of the RR interval during walking, whereas the conventional heart sound sensor is disturbed by vibration due to walking. As a result, it is difficult to catch the peak.

  FIG. 16 illustrates a detection waveform from the tip of the fingertip by the pulsation detecting device according to the present invention, and FIG. 17 illustrates a detection waveform from the tip of the fingertip by the conventional heart sound sensor. The first half of the waveform was measured during walking, and the second half was measured at rest. Here again, the waveform measured by the pulsation detecting device SNSR of the present invention clearly shows the peak position of the RR interval during walking, whereas the conventional heart sound sensor has a disturbance in the peak position. It is difficult to understand.

  FIG. 19 illustrates a detection waveform from the buttocks by the pulsation detection device SNSR according to the present invention, and FIG. 20 illustrates a detection waveform from the buttocks by a conventional heart sound sensor. 19 and 20, the pulsation detecting device SNSR was incorporated into the seat surface of the chair 6 as illustrated in FIG. The waveforms in the first half of FIGS. 19 and 20 are waveforms when the subject (here, the subject) 5 is sitting on the chair 6 and operating the keyboard, and the waveforms in the second half are stationary. Here, since the respiration waveform having a low frequency is also detected, the waveform is different from that shown in FIGS. 14 to 17 and has a slow undulation, but the pulsation detecting device SNSR of the present invention is used. By using it, the peak of the RR interval can be easily detected. In the conventional heart sound sensor, as shown in FIG.

  As described above, by using the pulsation detecting device according to the present invention, stable heart sounds and pulse measurements can be performed without being affected by noise caused by body movements even during walking or running. The pulsation detecting device according to the present invention can easily measure heart sounds and pulses even in a state of moving with respect to various parts of the subject, and is required for health equipment, medical equipment, and in-vehicle equipment. It can contribute to realization of stable acquisition of biological information.

  Although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof.

  For example, the shape of the casing is not limited to a rectangular shape and can be changed to an appropriate shape such as a circle. In the case of using the support columns, the number is not limited to three. For example, it is possible to arrange the columns having different lengths along the respective edges in the longitudinal direction of the casing. Moreover, it is not limited to using the raw material which exhibits rubber elasticity or viscoelasticity for the support | pillar which is an example of a branch member, It does not prevent forming with resin etc. which do not have a softness | flexibility. The pulsation detecting device can be widely used not only for measuring heart sounds and pulses but also for measuring body sounds.

SNSR pulsation detecting device 1 casing 2 microphone 3, 4 air chamber 5 subject MIP 1 first mechanical impedance region MIP 2 second mechanical impedance region 30 internal space 31 vibrating membranes 32, 33, 34 struts 40 internal space 41 vibrating membrane 42 bonding structure Body 42
50 Bone, muscle or tendon 51 Arteries

Claims (14)

A microphone that receives sound pressure and converts it into an electrical signal;
A casing to which the microphone is attached;
An air chamber formed on the front side of the casing in communication with the sound pressure input surface of the microphone;
The air chamber is fixed to a peripheral portion of the casing so as to contain the microphone, and has a vibrating membrane that allows the outer surface to come into contact with the surface of the subject. A pulsation detecting device comprising: a support member that three-dimensionally supports the vibration membrane so as to form a space and forms mechanical impedances that are different in magnitude against a pressing force to the subject at different portions of the vibration membrane.   2. The pulsation detecting device according to claim 1, wherein the casing has a pressure adjusting hole having a predetermined inner diameter and length for communicating the internal space of the air chamber with atmospheric pressure.   2. The support member according to claim 1, wherein the support member is a support column erected at an arbitrary position of the casing, and a mechanical impedance of the vibration film in a portion not in contact with the support column is smaller than a mechanical impedance of the vibration film in a region in contact with the support column. Pulsation detection device.   4. The pulsation detecting device according to claim 3, wherein the support column is made of a viscoelastic body or a rubber elastic body.   5. The pulsation detecting device according to claim 3, wherein the vibration film is made of a rubber elastic body that is softer than the support column.   4. The support column according to claim 3, wherein the support column includes a plurality of support columns having different lengths, and a part of an outer surface of the vibrating membrane that can contact the subject is supported by a support column that is longer than the other and protrudes. , Beat detection device.   The pulsation detecting device according to claim 6, wherein the vibration film has a three-dimensional shape having a concave central portion.   The pulsation detecting device according to claim 6, wherein the vibration film has a three-dimensional shape with a convex center part.   2. The vibrating membrane according to claim 1, wherein the support member is a joint structure of a random loop in which continuous filaments of fibers made of a thermoplastic elastomer are twisted, and a force against a pressing force against a subject is small. The pulsation detecting device is configured such that the mechanical impedance is smaller than the mechanical impedance of the vibrating membrane at a site where the force against the pressing force to the subject is large.   The pulsation detecting device according to claim 9, wherein the continuous linear body has a wire diameter of 0.1 mm to 3.0 mm.   The pulsation detecting device according to claim 9 or 10, wherein the vibration film is made of a rubber elastic body.   10. The thickness dimension of the joint structure in the front and back direction of the vibration membrane in claim 9 is partially different, and the vibration membrane has a part of the outer surface that can be brought into contact with a subject with a thickness of the joint structure. A pulsation detector that protrudes according to its dimensions.   The pulsation detecting device according to claim 12, wherein the vibration film has a three-dimensional shape having a concave central portion.   The pulsation detecting device according to claim 12, wherein the vibration film has a three-dimensional shape with a convex center part.

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