Electronic auscultation device and vibration detection device

Abstract

To output a vibration signal having a high SN ratio.SOLUTION: The electronic stethoscope apparatus includes a first diaphragm that is brought into contact with a living body surface, a second diaphragm that forms a sealed space together with a member including the first diaphragm at least while the first diaphragm is in contact with the living body surface, and an output unit that outputs a vibration signal indicating a vibration state of the second diaphragm, wherein a size of the second diaphragm is smaller than a size of the first diaphragm and a Young's modulus of the second diaphragm is smaller than a Young's modulus of the first diaphragm.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electronic auscultation device and a vibration detection device. [Background technology]

[0002] Electronic auscultation devices that acquire biological sounds based on vibrations on the surface of a living body are becoming popular. Patent Document 1 discloses a configuration in which the vibration state of a diaphragm is detected by a vibration sensor. The vibration sensor outputs a "vibration signal" that indicates the vibration state of the diaphragm. The vibration signal output by the vibration sensor when the diaphragm is in contact with a living body is also referred to as a biological sound signal that indicates biological sounds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-47095 Summary of the Invention [Problem to be solved by the invention]

[0004] Since the vibration of the diaphragm caused by the vibration of the living body is very small, the signal-to-noise ratio (SN ratio) of the vibration signal can be low.

[0005] The present invention provides a technique for outputting a vibration signal with a high signal-to-noise ratio. [Means for solving the problem]

[0006] According to one aspect of the present invention, an electronic auscultation device comprises a first diaphragm that is brought into contact with a biological surface, a second diaphragm that forms a sealed space together with a member including the first diaphragm at least while the first diaphragm is in contact with the biological surface, and an output means that outputs a vibration signal that indicates the vibration state of the second diaphragm, wherein the size of the second diaphragm is smaller than the size of the first diaphragm and the Young's modulus of the second diaphragm is smaller than the Young's modulus of the first diaphragm. [Effects of the Invention]

[0007] According to the present invention, a vibration signal with a high S / N ratio can be output. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B illustrate example exterior views of an electronic auscultation device, according to some embodiments. [Figure 2] FIG. 1 illustrates an example chestpiece configuration according to one embodiment. [Figure 3] 1 is an illustration of the operation of a chestpiece, according to one embodiment. [Figure 4] FIG. 10 is an explanatory diagram illustrating the movement of reflected light due to vibration of a diaphragm. [Figure 5] FIG. 4 is a diagram showing an example of the relationship between the displacement of a diaphragm and the amplitude of a vibration signal. [Figure 6] FIG. 1 is a block diagram illustrating an example configuration of an electronic auscultation device, according to some embodiments. [Figure 7] FIG. 1 illustrates an example chestpiece configuration according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] First Embodiment 1(A) and 1(B) show a schematic external view of the electronic auscultation device 100. In the following, a coordinate system CS will be indicated in the drawings as necessary. The coordinate system CS is a three-dimensional Cartesian coordinate system having mutually orthogonal x-, y-, and z-axes. The positive direction of the z-axis is also referred to as the upper side, and the negative direction of the z-axis is also referred to as the lower side. The electronic auscultation device 100 includes a chestpiece 110 and a gripping portion 120. The chestpiece 110 is the part that comes into contact with a living body during diagnosis using the electronic auscultation device 100. The chestpiece 110 detects the displacement of the diaphragm, and is therefore also referred to as a displacement detection device or a diaphragm displacement detection device. The chestpiece 110 can also be referred to as a vibration detection device, as it detects the vibration of the diaphragm.

[0011] The chestpiece 110 is attached to one end of the gripping portion 120 (negative side of the x-axis in FIG. 1). The gripping portion 120 is the portion that is gripped when a user of the electronic auscultation device 100 (e.g., a doctor, nurse, or public health nurse) presses the diaphragm of the chestpiece 110 against the surface of a living body. Hereinafter, the "user of the electronic auscultation device 100" will be referred to simply as the "user." The gripping portion 120 may also be called a handle, a grip, a handle, or the like.

[0012] The grip part 120 has a battery and a circuit board inside a housing 121. The battery stores operating power for the electronic auscultation device 100. The circuit board has circuit elements for controlling the operation of the electronic auscultation device 100. The grip part 120 has a display unit 122, an operation unit 123, a power switch 124, and a connector 125 on the outer surface of the housing 121.

[0013] The display unit 122 displays the status of the electronic auscultation device 100. For example, the display unit 122 may include multiple indicators (four indicators in the example of FIG. 1(A)). Each indicator may be configured with a light-emitting diode (LED). The multiple indicators may include an indicator indicating whether the power of the electronic auscultation device 100 is on or off. The multiple indicators may include an indicator indicating the current operating mode of the electronic auscultation device 100. The multiple indicators may include an indicator indicating whether the electronic auscultation device 100 is wirelessly connected to an external device. The multiple indicators may include an indicator indicating whether the chestpiece 110 is pressed against a living body surface. Instead of or in addition to the multiple indicators, the display unit 122 may display the status of the electronic auscultation device 100 using a liquid crystal panel or an electrostatic panel.

[0014] The operation unit 123 accepts operations from the user. The operation unit 123 may include, for example, multiple physical buttons. For example, the operation unit 123 may include an adjustment button for adjusting the level of the output sound. The operation unit 123 may also include a button for switching the operation mode of the electronic auscultation device 100. The operation unit 123 may include a touch panel instead of multiple physical buttons. Furthermore, the display unit 122 and the operation unit 123 may be integrated into a touch screen.

[0015] The power switch 124 is a switch that switches the power of the electronic auscultation device 100 on and off. The connector 125 is a connector for receiving a cable or a connector of an external device. Power is supplied from the external device to the battery of the grip portion 120 through the connector 125. The power switch 124 may be provided on the chestpiece 110 instead of the grip portion 120. The connector 125 may be provided on the chestpiece 110 instead of the grip portion 120. Furthermore, the electronic auscultation device 100 may not include the connector 125. In this case, the electronic auscultation device 100 may have a wireless charging function or may be configured to have a replaceable battery.

[0016] Fig. 2 shows the configuration of chestpiece 110. The upper side of Fig. 2 is a cross-sectional view of chestpiece 110, and the lower side of Fig. 2 is a plan view of chestpiece 110. Note that in the plan view of Fig. 2, only light-emitting circuit board 203, light-receiving circuit board 205, diaphragm 206, diaphragm 207, and reflecting member 208 are shown in order to clarify the positional relationship of the components.

[0017] The light-emitting element 202 is a light source that emits light. In this embodiment, the light-emitting element 202 is a light-emitting diode (LED), but other light-emitting elements such as a laser diode (LD) can also be used as the light-emitting element 202. The light-emitting element 202 is mounted on a light-emitting circuit board 203. For example, a peripheral circuit for controlling the light emission of the light-emitting element 202 is mounted on the light-emitting circuit board 203. The light-emitting circuit board 203 including the light-emitting element 202 functions as a light-emitting unit.

[0018] The light receiving element 204 receives light and generates an electrical signal based on the amount of received light. The light receiving element 204 may be, for example, a phototransistor or a complementary metal-oxide semiconductor (CMOS) sensor. In this embodiment, the number of light receiving elements 204 is one, but a configuration using multiple light receiving elements 204 is also possible. The light receiving element 204 is mounted on a light receiving circuit board 205. Peripheral circuits and the like are mounted on the light receiving circuit board 205 for reading out signals from the light receiving element 204 and outputting electrical signals. The light receiving circuit board 205 including the light receiving element 204 functions as a light receiving unit.

[0019] The holding member 201 holds the light-emitting circuit board 203 and the light-receiving circuit board 205. The light-emitting circuit board 203 and the light-receiving circuit board 205 are fixed to the holding member 201. The holding member 201 also holds a diaphragm 206. The diaphragm 206 extends along the xy plane of the coordinate system CS. The diaphragm 206 is a membrane having a circular outer edge in a plan view. The diaphragm 206 is arranged to contact a biological surface. The diaphragm 206 constitutes a part of the outer surface of the chestpiece 110. The diaphragm 206 has an outer surface arranged to contact the biological surface when the electronic auscultation device 100 is in use, and an inner surface opposite the outer surface.

[0020] Diaphragm 206 has fixed portion 206c fixed to holding member 201. Fixed portion 206c is located on the outer periphery of diaphragm 206. The inner periphery of diaphragm 206 (i.e., the portion inside fixed portion 206c) is not fixed to holding member 201. Therefore, diaphragm 206 can vibrate in the z-axis direction with fixed portion 206c as a node. Specifically, when chestpiece 110 is in use, diaphragm 206 vibrates with fixed portion 206c as a node in response to displacement of the body surface. In this vibration, the center of diaphragm 206 becomes the antinode. Diaphragm 206 functions as a vibrating unit.

[0021] The holding member 201 further holds a diaphragm 207. The diaphragm 207 extends along the xy plane of the coordinate system CS. The diaphragm 207 may extend along a plane different from the xy plane of the coordinate system CS. The diaphragm 207 is a membrane having a circular outer edge in a plan view. The diaphragm 207 is disposed inside the chestpiece 110 on the positive side of the z axis relative to the diaphragm 206. The x-axis and y-axis coordinates of the center 207e of the diaphragm 207 may be the same as the x-axis and y-axis coordinates of the center 207e of the diaphragm 207. Note that the x-axis and y-axis coordinates of the center 207e of the diaphragm 207 may be different from the x-axis and y-axis coordinates of the center 206.

[0022] Diaphragm 207 has fixed portion 207c fixed to holding member 201. Fixed portion 207c is located on the outer periphery of diaphragm 207. The inner periphery of diaphragm 207 (i.e., the portion inside fixed portion 207c) is not fixed to holding member 201. Therefore, diaphragm 207 can vibrate in the z-axis direction with fixed portion 207c as a node. In this vibration, center 207e of diaphragm 207 becomes an antinode. Diaphragm 207 functions as a vibrating part. Diaphragm 207 has an outer surface facing the inner surface of diaphragm 206 and an inner surface opposite the outer surface.

[0023] In this embodiment, the size of diaphragm 207 is smaller than the size of diaphragm 206. Note that the size of diaphragm 207 refers to the size of the inner periphery of diaphragm 207 excluding fixed portion 207c. Similarly, the size of diaphragm 206 refers to the size of the inner periphery of diaphragm 206 excluding fixed portion 206c. The inner peripheries of diaphragms 207 and 206 are vibrable regions, and are also referred to as "vibrable regions" below. Therefore, the size of diaphragms 206 and 207 refers to the size of the vibrable region of diaphragms 206 and 207. Furthermore, in this embodiment, the Young's modulus of longitudinal elasticity (Young's modulus) of diaphragm 207 is smaller than the Young's modulus of diaphragm 206.

[0024] The reflecting member 208 is a reflecting portion that reflects light emitted from the light-emitting element 202. The reflecting member 208 is bonded to the inner surface of the diaphragm 207. Therefore, the reflecting member 208 vibrates in the z-axis direction in conjunction with the vibration of the diaphragm 207. The reflecting member 208 has a circular outer edge in a plan view. The outer edge of the reflecting member 208 may have other shapes. The reflecting member 208 is disposed in a position that covers the region 207d including the center 207e of the diaphragm 207. Since the vibration of the diaphragm 207 is greatest at the center 207e, the vibration of the diaphragm 207 can be detected with high sensitivity by reflecting the light from the light-emitting element 202 in the region including the center 207e. Note that in this embodiment, the reflecting member 208 is disposed in a position that covers the center 207e. However, the reflecting member 208 may also be disposed in a position that covers a region of the diaphragm 207 that does not include the center 207e. The reflecting member 208 is formed, for example, of an aluminum-deposited film.

[0025] The light emitting element 202 emits light toward the reflecting member 208, and the upper surface of the reflecting member 208 reflects the light emitted by the light emitting element 202. That is, the upper surface of the reflecting member 208 functions as a light reflecting surface. In the following description, the reflection of light on the upper surface of the reflecting member 208 (that is, the light reflecting surface) will be simply referred to as light being reflected by the reflecting member 208. The reflecting member 208 specularly reflects (in other words, specularly reflects) the light emitted by the light emitting element 202. In the following description, the light traveling from the light emitting element 202 toward the reflecting member 208 will be referred to as incident light 212, and the light after the incident light 212 is reflected will be referred to as reflected light 213.

[0026] In this embodiment, the reflecting member 208 is a separate member from the diaphragm 207. However, the reflecting member 208 may be a coating layer applied to the diaphragm 207. The reflecting member 208 may also be a sticker or the like attached to the diaphragm 207. The reflecting member 208 may be formed as the same member as the diaphragm 207, and at least a part of the inner surface of the diaphragm 207 may also serve as a reflecting portion. For example, the entire inner surface of the diaphragm 207 may have a high reflectivity that can reflect light to an extent that can be detected by the light receiving element 204. Alternatively, only a region of the inner surface of the diaphragm 207 that is reached by light irradiated by the light emitting element 202 may have such a high reflectivity.

[0027] Light emitting element 202 can be arranged so that, when diaphragm 207 is not vibrating, it irradiates area 208a of reflecting member 208 that includes a portion covering center 207e of diaphragm 207. When diaphragm 207 is not vibrating, diaphragm 207 is flat.

[0028] In this embodiment, as described above, an LED that emits diffused light is used as the light-emitting element 202. Therefore, the chestpiece 110 has an aperture 210 that limits the range of light emitted from the light-emitting element 202. The aperture 210 allows only a portion of the light emitted by the light-emitting element 202 to be irradiated onto the reflecting member 208. In the example of FIG. 2, an opening formed in the holding member 201 corresponds to the aperture 210. Note that, in this embodiment, a component that emits diffused light has been described as an example of the light-emitting element 202, but instead, a component that emits linear light may be used as the light-emitting element 202, and the linear light may be irradiated toward the region 208a. Note that the aperture 210 may also be used when the light-emitting element 202 is a component that emits linear light.

[0029] The light receiving element 204 is disposed so as to receive the reflected light 213. Specifically, the light receiving element 204 is disposed at a position where the amount of received reflected light 213 changes due to vibration of the diaphragm 207 in the z-axis direction. The light receiving element 204 is disposed so as to receive more light of the reflected light 213 when the diaphragm 207 is flat than when the diaphragm 207 is not flat. Therefore, the light receiving element 204 outputs an electrical signal corresponding to the vibration of the diaphragm 207. The electrical signal output by the light receiving element 204 is output via a peripheral circuit mounted on the light receiving circuit board 205.

[0030] Chestpiece 110 has aperture 211 that limits the range of light that enters light receiving element 204. Aperture 211 prevents diffusely reflected light from entering light receiving element 204, and allows only at least a portion of the light from reflecting member 208 (i.e., primarily reflected light) to reach light receiving element 204. In the example of FIG. 2, an opening formed in holding member 201 functions as aperture 211. Alternatively, aperture 211 may be formed in a different manner.

[0031] A housing 209 is attached to the outer circumferential upper surface of the holding member 201. The housing 209 covers the light-emitting circuit board 203 and the light-receiving circuit board 205 and prevents ambient sound from entering the housing 209. The outer edges of the diaphragm 206, the holding member 201, and the housing 209 may coincide with one another in a plan view relative to the outer surface of the diaphragm 206. In this embodiment, the housing 209 is made of stainless steel.

[0032] By fixing the diaphragms 206 and 207 to the holding member 201, an internal space 214 is formed, surrounded by the diaphragms 206, 207, and the holding member 201. The internal space 214 is a sealed space so that the diaphragm 207 vibrates in conjunction with the vibration of the diaphragm 206. A sealed space is a space that is sealed off from a specific substance. In other words, a sealed space is a space in which the inflow of a specific substance from an external space and the outflow of a specific substance to an external space are restricted. The specific substance to be sealed may vary depending on the environment in which the electronic auscultation device 100 is used. For example, when the electronic auscultation device 100 is used on land, the substance to be sealed may be a gas (e.g., air). When the electronic auscultation device 100 is used underwater, the substance to be sealed may be a liquid (e.g., water). In the following description, it is assumed that the object to be sealed is air, and that the internal pressure of the internal space 214 when both the diaphragm 206 and the diaphragm 207 are flat is equal to atmospheric pressure.

[0033] The internal space 214 only needs to be sealed at least when the electronic auscultation device 100 is in use, and does not need to be sealed when the electronic auscultation device 100 is not in use. For example, the diaphragm 206 may have tiny holes that allow air to flow in and out, and the holes in the diaphragm 206 may be closed by pressing the diaphragm 206 against the surface of the living body, thereby sealing the internal space 214.

[0034] At least one of diaphragm 206 and diaphragm 207 may have a light-shielding property in order to prevent light different from reflected light 213 by light-emitting element 202 from entering light-receiving element 204. Alternatively or additionally, at least one of diaphragm 206 and diaphragm 207 may be covered with a light-shielding film. Similarly, holding member 201 may have a light-shielding property or may be covered with a light-shielding film.

[0035] By fixing diaphragm 207 to holding member 201, an internal space 215 is formed that is surrounded by diaphragm 207 and holding member 201. Internal space 215 may be an unsealed space to prevent the vibration of diaphragm 207 from being hindered by the vibration of diaphragm 206. In this case, the internal pressure of internal space 215 is equal to atmospheric pressure.

[0036] An example of the operation of the chestpiece 110 of the electronic auscultation device 100 will be described with reference to Figure 3. As shown in Figures 3(A) and 3(B), the chestpiece 110 is used with the diaphragm 206 in contact with the biological surface 300. As will be described later, when the diaphragm 206 is displaced in the z-axis direction due to displacement of the biological surface 300 in the z-axis direction, the diaphragm 207 is also displaced in the z-axis direction.

[0037] FIG. 3A shows a cross section of the chestpiece 110 when the diaphragm 207 is flat. The light-emitting element 202 and the light-receiving element 204 are arranged so that, when the diaphragm 207 is flat, the light-receiving element 204 receives more reflected light 213 when the diaphragm 207 is displaced in the z-axis direction. The light-receiving element 204 amplifies and outputs a photocurrent corresponding to the amount of received light. The peripheral circuit of the light-receiving circuit board 205 converts the photocurrent output from the light-receiving element 204 into a voltage, and outputs the resulting output value as a vibration signal. In this specification, the vibration signal refers to a signal indicating the vibration state of the diaphragm 207. In this embodiment, the light-receiving circuit board 205 outputs a signal indicating the time change in the displacement of the diaphragm 207 in the z-axis direction as the vibration signal. Therefore, in this embodiment, the vibration signal can also be referred to as a displacement signal indicating the displacement of the diaphragm 207 in the z-axis direction.

[0038] FIG. 3B shows a cross-sectional view of the chestpiece 110 when the biological surface 300 is displaced upward. The distance between the light-emitting element 202 and the upper surface of the reflecting member 208 is denoted by d3. When the biological surface 300 is displaced upward and the diaphragm 207 is displaced upward accordingly, the distance d3 decreases. Accordingly, the region 208a of the reflecting member 208 that is irradiated with the incident light 212 moves closer to the light-emitting element 202, and the reflected light 213 also moves closer to the light-emitting element 202. This reduces the amount of reflected light 213 that reaches the light-receiving element 204, reducing the value of the vibration signal generated by the light-receiving circuit board 205. In the state shown in FIG. 3B, none of the reflected light 213 reaches the light-receiving element 204, and therefore the value of the vibration signal is ideally zero.

[0039] Thus, in the chestpiece 110, the light-emitting element 202 and the light-receiving element 204 are arranged so that the amount of light reaching the light-receiving element 204 changes in accordance with the movement of the diaphragm 207. Because the diaphragm 207 vibrates in conjunction with the vibration of the biological surface 300, the vibration signal generated by the light-receiving circuit board 205 represents the displacement and vibration of the biological surface 300.

[0040] 3(B), the displacement of the diaphragm 206 in the z-axis direction is represented by d1. The displacement d1 of the diaphragm 206 in the z-axis direction is equivalent to the displacement of the biological surface 300 in the z-axis direction. For example, since the vibration of the biological surface 300 that occurs in response to bodily movements such as heartbeat and breathing is minute, the displacement d1 is also a minute value.

[0041] In this embodiment, an internal space 214 (sealed space) sealed by a diaphragm 206, a diaphragm 207, and a holding member 201 is formed. The internal space 214 on the outer surface side (first surface side) of the diaphragm 207 is a sealed space, but the internal space 215 on the inner surface side (second surface side) of the diaphragm 207 is an unsealed space. Therefore, when the internal pressure of the internal space 214 fluctuates due to the displacement of the diaphragm 206, the diaphragm 207 is displaced so as to mitigate the fluctuation of the internal pressure of the internal space 214. Therefore, the diaphragm 207 vibrates in response to the vibration of the diaphragm 206. As shown in Fig. 3(B), when the displacement amount of the diaphragm 206 in the z-axis direction is d1, the displacement amount of the diaphragm 207 in the z-axis direction is represented by d2.

[0042] As shown in Fig. 3(B), when the diaphragm 206 is displaced by a displacement amount d1, let the volume of the space formed by the displaced diaphragm 206 and the diaphragm 206 in the flat state be V1. Also, as shown in Fig. 3(B), when the diaphragm 207 is displaced by a displacement amount d2, let the volume of the space formed by the displaced diaphragm 207 and the diaphragm 207 in the flat state be V2. When the Young's modulus of the diaphragm 207 is smaller than the Young's modulus of the diaphragm 206, V1 and V2 are substantially equal. As described above, since the size (area) of the diaphragm 207 is smaller than the size (area) of the diaphragm 206, the relationship d1 < d2 holds. That is, the displacement amount d2 of the diaphragm 207 in the z-axis direction is larger than the displacement amount d1 of the diaphragm 206 in the z-axis direction.

[0043] As an example, the diaphragm 206 can be formed of vinyl chloride, and the diaphragm 207 can be formed of rubber. Rubber has a smaller Young's modulus and is more deformable compared to vinyl chloride.

[0044] If diaphragm 207 has a high Young's modulus and a large force for maintaining its original shape, the function of diaphragm 207 in mitigating fluctuations in the internal pressure of internal space 214 becomes weaker, and V1 > V2 may result. In this state, the internal pressure of internal space 214 becomes higher than atmospheric pressure due to the displacement of diaphragm 206, and the displacement amount d2 of diaphragm 207 is unlikely to become large.

[0045] Note that even if V1>V2, the displacement amount d2 may be larger than the displacement amount d1 depending on the sizes of the diaphragms 206 and 207. Therefore, as long as the displacement amount d2 is larger than the displacement amount d1, the Young's modulus of the diaphragm 207 may be equal to or larger than the Young's modulus of the diaphragm 206. In other words, the Young's modulus of the diaphragm 207 may be set so that the magnitude of the displacement of the diaphragm 207 (displacement amount d2) caused by the displacement of the diaphragm 206 in contact with the biological surface 300 is larger than the magnitude of the displacement of the diaphragm 206 (displacement amount d1).

[0046] As described above, by making the size of diaphragm 207 smaller than the size of diaphragm 206, the displacement amount of diaphragm 207 can be made larger than the displacement amount of diaphragm 206, i.e., the displacement amount of the living body surface. Therefore, by detecting the vibration of diaphragm 207, the S / N ratio of the vibration signal can be made higher compared to when the vibration of diaphragm 206 is detected.

[0047] Next, the relationship between the displacement amount of the biological surface 300, the incident angle of the incident light 212, and the displacement amount of the reflected light 213 will be described with reference to Fig. 4. In Fig. 4, position 401 indicates the reference position of the upper surface of the reflecting member 208. In this embodiment, the upper surface of the reflecting member 208 when the diaphragm 207 is flat is taken as the reference position. Position 402 indicates a position where the upper surface of the reflecting member 208 is displaced upward from position 401 by a displacement amount d4. Because the displacement amount d4 of the reflecting member 208 is minute, even when the upper surface of the reflecting member 208 is at position 402, the upper surface of the reflecting member 208 is considered to be flat.

[0048] In FIG. 4, optical axis 403 indicates the optical axis of incident light 212. The angle of incidence of light emitted by light emitting element 202 (i.e., incident light 212) on reflecting member 208 is represented by θ. The angle of incidence θ of incident light 212 is defined by the angle between optical axis 403 of incident light 212 and the normal to the top surface of reflecting member 208. The optical axis of reflected light 213 when the top surface of reflecting member 208 is at position 401 is represented by optical axis 404. The optical axis of reflected light 213 when the top surface of reflecting member 208 is at position 402 is represented by optical axis 405. Since incident light 212 is specularly reflected by the top surface of reflecting member 208, the reflection angle of reflected light 213 is also θ. Optical axis 404 and optical axis 405 are parallel to each other. The amount of displacement from optical axis 404 to optical axis 405 is represented by d5. In this case, d5=2×d4×sinθ (1) As described in Fig. 3, the amount of light received by the light receiving element 204 decreases as d5 increases.

[0049] Next, the relationship between the displacement of the biological surface 300 and the amplitude of the vibration signal will be described. As described above, the amount of light received by the light receiving element 204 decreases as d5 increases, and therefore the amplitude Sd of the vibration signal decreases as d5 increases. Sd=Vmax-k×d5 (2) Here, Vmax is the amplitude of the vibration signal when the displacement d5 is zero, and k is a proportionality coefficient determined by the amplification factor of the amplifier circuit of the light receiving circuit board 205. By substituting equation (1) into equation (2), Sd=Vmax-2k×d4×sinθ (3) This relationship is shown in Figure 5.

[0050] The amplitude Sd of the vibration signal decreases linearly as the displacement amount d4 increases, as shown by graph 500 in Fig. 5. The displacement amount at which the amplitude Sd of the vibration signal becomes zero is represented as dmax. When the displacement amount d4 exceeds dmax, the reflected light 213 no longer reaches the light receiving element 204, and therefore the vibration signal remains zero even if the displacement amount d4 increases.

[0051] Therefore, the proportionality coefficient k and the incident angle θ are set so that the displacement d4 is in the range of 0 to dmax inclusive within the range in which the vibration of the diaphragm 207 is expected (this is referred to as the operating range of the diaphragm 207). As shown in graph 500, the light emitting element 202 and the light receiving element 204 are arranged so that the amount of light reaching the light receiving element 204 changes monotonically in response to the movement of the reflecting member 208 in one direction within the operating range of the diaphragm 207.

[0052] Referring to FIG. 6, an example of the hardware configuration of the electronic auscultation device 100 will be described. The electronic auscultation device 100 includes the chestpiece 110 and a sound output unit 610. The sound output unit 610 is implemented by multiple circuit elements mounted on a circuit board included in the grip unit 120. The multiple circuit elements include a processor. The processor constituting the sound output unit 610 outputs a sound signal based on a vibration signal generated by the chestpiece 110. The sound signal output by the sound output unit 610 represents the body sounds of a living body (e.g., a human) having a body surface 300. The sound signal is transmitted to a sound output device 620 such as earphones or headphones. The sound signal may also be transmitted to a computer 630 (e.g., a personal computer, smartphone, tablet, etc.) simultaneously with being transmitted to the sound output device 620. A user such as a doctor, nurse, or public health nurse can listen to the body sounds represented by the sound signal using the sound output device 620 or the computer 630. The sound output device 620 is a wired or wireless earphone or headphone.

[0053] The sound output unit 610 has the components shown in FIG. 6 . Since the sound output unit 610 conforms to the earphones or headphones, it can output sound signals via both wireless and wired communication. The following describes the process by which the sound output device 620 outputs a sound signal via wired communication. The vibration signal output from the chestpiece 110 is filtered and amplified by the filter / amplifier 618 and supplied to the A / D converter 611 and the amplifier 615. The amplifier 615 further amplifies the output from the filter / amplifier 618 and supplies it to the wired communication unit 617. The wired communication unit 617 provides the amplified sound signal to the sound output device 620. The wired communication unit 617 is, for example, a 3.5 mm AUX terminal. The amplification gain of the amplifier 615 is adjusted by the volume adjustment unit 616. The sound output device 620 may be considered to constitute a part of the electronic auscultation device 100. In this case, the electronic stethoscope device 100 includes a chestpiece 110 , a grip portion 120 , and a sound output device 620 .

[0054] Next, the process by which the sound output device 620 outputs a sound signal via wireless communication will be described. The A / D converter 611 digitizes the output from the filter / amplifier 618. The digital vibration signal is then amplified by the amplifier 612 and supplied to the encoder 613. The encoder 613 performs signal processing, such as data compression and encoding, on the amplified sound signal to generate sound data for wireless communication. The order of processing by the amplifier 612 and the encoder 613 may be reversed. Then, a wireless communication unit 614 compliant with a wireless communication standard such as Bluetooth (registered trademark) provides the processed sound output data to the sound output device 620. The amplification gain of the amplifier 612 is adjusted by the volume adjustment unit 616. Although the above-described example of the electronic auscultation device 100 is capable of outputting a sound signal via both wireless and wired communication, it may also be capable of outputting a sound signal via only one of these communication methods.

[0055] The output of sound signals to the computer 630 is similar to the output of sound signals to the sound output device 620. The computer 630 can also visually display waveform data generated based on the sound signals. The waveform data may be generated by the computer 630 or by the electronic auscultation device 100. Furthermore, part or all of the signal processing and sound output processing by the electronic auscultation device 100 may be performed by an external device (e.g., the sound output device 620 or the computer 630).

[0056] As described above, according to this embodiment, the electronic auscultation device 100 has a diaphragm 206 that is brought into contact with a target for vibration detection, such as the surface of a living body, and a diaphragm 207 that is smaller than the diaphragm 206, and a sealed space is formed by the members including the diaphragms 206 and 207. Note that the sealed space only needs to be formed while the diaphragm 206 is in contact with the target for vibration detection. The electronic auscultation device 100 detects the vibration state of the diaphragm 207 and outputs a vibration signal. Since the vibration of the diaphragm 207 is an amplified version of the vibration of the diaphragm 206, it is possible to output a vibration signal with a higher S / N ratio than by detecting the vibration state of the diaphragm 206.

[0057] Second Embodiment Next, the second embodiment will be described, focusing on the differences from the first embodiment. Chestpiece 110 of the first embodiment outputs a signal indicating the change over time in the amount of displacement of diaphragm 207 as a vibration signal indicating the vibration state of diaphragm 207. Chestpiece 110 of this embodiment detects the acceleration due to the vibration of diaphragm 207 using acceleration sensor 701, and outputs a signal indicating the change over time in the acceleration due to the vibration of diaphragm 207 as a vibration signal indicating the vibration state of diaphragm 207.

[0058] 7 shows the configuration of chestpiece 110 of this embodiment, and corresponds to FIG. 2 of the first embodiment. Chestpiece 110 of this embodiment does not include light-emitting element 202, light-emitting circuit board 203, light-receiving element 204, light-receiving circuit board 205, and reflecting member 208 described in the first embodiment. Furthermore, there is no need to provide apertures 210 and 211 on holding member 201. Instead, in this embodiment, acceleration sensor 701 is attached to diaphragm 207.

[0059] The acceleration sensor 701 detects acceleration caused by the displacement and vibration of the diaphragm 207. Because the acceleration sensor 701 detects the vibration of the diaphragm 207, it may also be called a vibration detection unit. The acceleration sensor 701 generates a signal indicating the change in the detected acceleration over time as a vibration signal. The acceleration sensor 701 may be mounted on a circuit board (not shown) and attached to the diaphragm 207. Alternatively, the acceleration sensor 701 may be connected to the circuit board (not shown) via lead wires (not shown). The circuit board receives and outputs the vibration signal from the acceleration sensor 701.

[0060] 7, acceleration sensor 701 is attached to the inner surface of diaphragm 207, but it may also be attached to the outer surface of diaphragm 207 as long as it vibrates in accordance with the vibration of diaphragm 207. Acceleration sensor 701 may be attached to diaphragm 207 so as to cover center 207e of diaphragm 207. Since the acceleration of diaphragm 207 changes most significantly at center 207e, arranging acceleration sensor 701 in a region including center 207e allows for sensitive detection of the acceleration of diaphragm 207. Note that acceleration sensor 701 may also be configured to be attached to diaphragm 207 so as not to cover center 207e of diaphragm 207.

[0061] A gyro sensor may be used instead of the acceleration sensor 701. In this case, the chestpiece 110 uses the gyro sensor to detect the angular velocity caused by the vibration of the diaphragm 207 and outputs a signal indicating the time change in the angular velocity caused by the vibration of the diaphragm 207 as a vibration signal indicating the vibration state of the diaphragm 207. Furthermore, a piezoelectric sensor may be used instead of the acceleration sensor 701. In this case, the chestpiece 110 uses the piezoelectric sensor to detect the pressure caused by the vibration of the diaphragm 207 and outputs a signal indicating the time change in the pressure caused by the vibration of the diaphragm 207 as a vibration signal indicating the vibration state of the diaphragm 207. Furthermore, a microphone may be used instead of the acceleration sensor 701. If a microphone is used, the microphone is disposed within the internal space 215 so as not to come into contact with the diaphragm 207. The microphone detects the vibration of the diaphragm 207 through a substance within the internal space 215, such as air, and outputs a vibration signal.

[0062] [Other embodiments] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0063] The disclosure of this embodiment includes the following configuration. (Configuration 1) a first diaphragm that is brought into contact with a biological surface; a second diaphragm that forms a sealed space together with a member including the first diaphragm at least while the first diaphragm is in contact with the surface of the living body; an output means for outputting a vibration signal indicating the vibration state of the second diaphragm; Equipped with An electronic stethoscope device, wherein the size of the second diaphragm is smaller than the size of the first diaphragm, and the Young's modulus of the second diaphragm is smaller than the Young's modulus of the first diaphragm. (Configuration 2) a holding member that holds the first diaphragm and the second diaphragm, 2. The electronic auscultation device according to claim 1, wherein the sealed space is formed by the first diaphragm, the second diaphragm, and the retaining member. (Configuration 3) the first surface side of the second diaphragm is the sealed space, The electronic stethoscope device according to configuration 2, wherein a second surface side of the second diaphragm opposite the first surface is an unsealed space. (Configuration 4) The second diaphragm is provided with a reflective surface that reflects light, The output means a light source that irradiates light toward the reflecting surface of the second diaphragm; a light receiving element that receives light emitted from the light source and reflected by the reflecting surface, and outputs a signal corresponding to the amount of received light as the vibration signal; 4. The electronic auscultation device of any one of configurations 1 to 3, comprising: (Configuration 5) 4. The electronic auscultation device according to any one of configurations 1 to 3, wherein the output means includes an acceleration sensor that detects acceleration due to vibration of the second diaphragm and outputs the vibration signal. (Configuration 6) 4. The electronic auscultation device according to any one of configurations 1 to 3, wherein the output means has a gyro sensor that detects an angular velocity caused by vibration of the second diaphragm and outputs the vibration signal. (Configuration 7) 4. The electronic auscultation device according to any one of configurations 1 to 3, wherein the output means has a piezoelectric sensor that detects pressure caused by vibration of the second diaphragm and outputs the vibration signal. (Configuration 8) 4. The electronic auscultation device according to any one of configurations 1 to 3, wherein the output means has a microphone that detects sound caused by vibration of the second diaphragm and outputs the vibration signal. (Configuration 9) a first diaphragm in contact with the vibrating surface; a second diaphragm that forms a sealed space together with a member including the first diaphragm at least while the first diaphragm is in contact with the surface; an output means for outputting a vibration signal indicating the vibration state of the second diaphragm; Equipped with A vibration detection device, wherein the size of the second diaphragm is smaller than the size of the first diaphragm, and the Young's modulus of the second diaphragm is smaller than the Young's modulus of the first diaphragm.

[0064] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0065] 110: Chest piece, 206, 207: Diaphragm

Claims

1. a first diaphragm that is brought into contact with a biological surface; a second diaphragm that forms a sealed space together with a member including the first diaphragm at least while the first diaphragm is in contact with the surface of the living body; an output means for outputting a vibration signal indicating the vibration state of the second diaphragm; Equipped with An electronic stethoscope device, wherein the size of the second diaphragm is smaller than the size of the first diaphragm, and the Young's modulus of the second diaphragm is smaller than the Young's modulus of the first diaphragm.

2. a holding member that holds the first diaphragm and the second diaphragm, The electronic auscultation device according to claim 1 , wherein the sealed space is formed by the first diaphragm, the second diaphragm, and the holding member.

3. a first surface side of the second diaphragm is the sealed space, The electronic auscultation device according to claim 2 , wherein a second surface of the second diaphragm opposite to the first surface is an unsealed space.

4. The second diaphragm is provided with a reflecting surface that reflects light, The output means a light source that irradiates light toward the reflecting surface of the second diaphragm; a light receiving element that receives light emitted from the light source and reflected by the reflecting surface, and outputs a signal corresponding to the amount of received light as the vibration signal; 4. The electronic auscultation device according to claim 1, further comprising:

5. 4. The electronic auscultation device according to claim 1, wherein the output means comprises an acceleration sensor that detects acceleration due to vibration of the second diaphragm and outputs the vibration signal.

6. 4. The electronic auscultation device according to claim 1, wherein the output means comprises a gyro sensor that detects an angular velocity caused by vibration of the second diaphragm and outputs the vibration signal.

7. 4. The electronic auscultation device according to claim 1, wherein the output means comprises a piezoelectric sensor that detects pressure due to vibration of the second diaphragm and outputs the vibration signal.

8. 4. The electronic auscultation device according to claim 1, wherein the output means comprises a microphone that detects a sound caused by the vibration of the second diaphragm and outputs the vibration signal.

9. a first diaphragm in contact with the vibrating surface; a second diaphragm that forms a sealed space together with a member including the first diaphragm at least while the first diaphragm is in contact with the surface; an output means for outputting a vibration signal indicating the vibration state of the second diaphragm; Equipped with A vibration detection device, wherein the size of the second diaphragm is smaller than the size of the first diaphragm, and the Young's modulus of the second diaphragm is smaller than the Young's modulus of the first diaphragm.

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