Electronic auscultation device

Abstract

An electronic auscultation device disclosed herein comprises: a diaphragm that comes into contact with a living body and vibrates together with the living body; a vibration detection unit that detects vibrations of the diaphragm; a generation unit that generates sound signal data, representing sounds generated by the living body, on the basis of a signal generated by the vibration detection unit; and a storage unit that starts storage processing for storing the sound signal data when the diaphragm is pressed by the living body.

Description

Electronic stethoscope

[0001] The present disclosure relates to an electronic stethoscope.

[0002] In recent years, electronic stethoscopes having sensors for measuring vibrations of a living body have begun to spread. Patent Document 1 proposes operating an application of a terminal device to record auscultation sound data.

[0003] Japanese Patent Application Laid-Open No. 2021-83944

[0004] When the storage process of sound signal data is started in response to obtaining a recording instruction from a user, noise generated when the electronic stethoscope contacts the living body surface and data in an extra section where the electronic stethoscope is not in contact with the living body surface are included in the sound signal data. Some aspects of the present disclosure provide a technique for storing high-quality sound signal data.

[0005] According to some embodiments, there is provided an electronic stethoscope comprising: a diaphragm that vibrates together with the living body before contacting the living body; a vibration detection unit that detects vibrations of the diaphragm; generation means for generating sound signal data representing a sound generated in the living body based on a signal generated by the vibration detection unit; and storage means for starting a storage process for storing the sound signal data when the diaphragm is pressed by the living body.

[0006] According to the above embodiment, high-quality sound signal data can be stored.

[0007] Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar configurations are denoted by the same reference numerals.

[0008] The attached drawings are included in the specification and constitute a part thereof, illustrating embodiments of the present invention and are used to explain the principles of the present invention together with the description thereof. Schematic diagram illustrating an example of the appearance of an electronic stethoscope in some embodiments. Schematic diagram illustrating an example of the configuration of a chestpiece in some embodiments. Schematic diagram illustrating an example of the operation of a chestpiece in some embodiments. Schematic diagram illustrating an example of the operation of a chestpiece in some embodiments. Schematic diagram illustrating an example of the movement of reflected light in some embodiments. Diagram illustrating the relationship between displacement and displacement signal in some embodiments. Block diagram illustrating an example of the circuit configuration of an electronic stethoscope in some embodiments. Block diagram illustrating an example of the functional configuration of an electronic stethoscope in some embodiments. Block diagram illustrating an example of the computer circuit configuration in some embodiments. Schematic diagram illustrating an example of the computer screen in some embodiments. Flow diagram illustrating an example of a method for saving data in an electronic stethoscope in some embodiments. Sequence diagram illustrating an example of cooperation between an electronic stethoscope and a computer in some embodiments. Diagram illustrating an example of saved sound signal data in a comparative example. Diagram illustrating an example of saved sound signal data in some embodiments. Diagram illustrating an example of saved sound signal data in some embodiments.

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claims. While the embodiments describe multiple features, not all of these features are necessary, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] [Appearance of the Electronic Auscultation Device] Referring to Figure 1, the appearance of the electronic auscultation device 100 according to some embodiments will be described. In Figure 1 and some subsequent drawings, a coordinate system CS, which is a three-dimensional Cartesian coordinate system having x, y, and z axes, is attached to indicate direction. Figure 1 shows the appearance of the electronic auscultation device 100 when viewed from a certain direction. The electronic auscultation device 100 is a medical device used by doctors, nurses, etc., as a diagnostic instrument to listen to the internal sounds of the body. The electronic auscultation device 100 is mainly used to listen to heart sounds and respiratory sounds.

[0011] As shown in Figure 1, the electronic auscultation device 100 has a chestpiece 110 and a gripping part 120. During diagnosis, the chestpiece 110 is brought into contact with the surface of the body and measures minute vibrations (displacements) of the body surface to capture biological sounds. The chestpiece 110 detects minute displacements of the body surface in close contact with it via a diaphragm 206, which will be described later.

[0012] The gripping section 120 is used to grip the diaphragm 206 when the user of the electronic stethoscope 100 brings it into close contact with a biological surface. The gripping section 120 is rod-shaped, and a chestpiece 110 is attached to one end (the negative x-axis direction in Figure 1). The gripping section 120 has a housing 121, which houses a battery and a circuit board. Circuit elements for controlling the operation of the electronic stethoscope 100 are mounted on the circuit board. The gripping section 120 further includes a display section 122, an operation section 123, a power switch 124, and a connector 125.

[0013] The display unit 122 has multiple indicators, each of which displays the status of the electronic stethoscope 100. For example, these indicators indicate the power-on status, the current operating mode, the communication status with the computer, and whether the chestpiece 110 is pressed against the body surface.

[0014] The control unit 123 has a number of physical buttons for receiving settings for the electronic stethoscope 100, and accepts user operations through these buttons. Specifically, the control unit 123 includes a volume up button 123a and a volume down button 123b for adjusting the volume of the output sound, and a mode switching button 123c for switching the operating mode of the electronic stethoscope 100. The electronic stethoscope 100 can operate by switching between a number of operating modes, including heart sound mode, respiratory sound mode, and power saving mode. Heart sound mode is an operating mode for listening to heart sounds. Respiratory sound mode is an operating mode for listening to respiratory sounds. Power saving mode is an operating mode that consumes less power than heart sound mode and respiratory sound mode. The electronic stethoscope 100 also receives instructions to start or stop recording by long-pressing the mode switching button 123c.

[0015] The power switch 124 is a switch that turns the power of the electronic stethoscope 100 on and off. The connector 125 is a connector for receiving a cable or connector of an external device. Power is supplied from the external device to the battery contained in the gripping part 120 through the connector 125.

[0016] [Cross-sectional configuration of the chestpiece of the electronic stethoscope] An example of the configuration of the chestpiece 110 will be described with reference to Figure 2. The upper part of Figure 2 shows a cross-sectional view of the chestpiece 110, and the lower part of Figure 2 shows a plan view of the chestpiece 110. In the plan view, only the light-emitting circuit board 203, light-receiving circuit board 205, diaphragm 206, and light-reflecting part 207 are shown in order to clarify the positional relationship of the components.

[0017] The chestpiece 110 includes a holding member 201, a light-emitting element 202, a light-emitting circuit board 203, a light-receiving element 204, a light-receiving circuit board 205, a diaphragm 206, a light-reflecting part 207, and a housing 208. The housing 208 houses the holding member 201, the light-emitting element 202, the light-emitting circuit board 203, the light-receiving element 204, the light-receiving circuit board 205, and the light-reflecting part 207. Since the holding member 201 has diaphragm portions 209 and 210 formed on it, the housing 208 also houses the diaphragm portions 209 and 210. The diaphragm 206, together with the housing 208, forms part of the exterior of the electronic stethoscope 100.

[0018] The light-emitting element 202 is a light source that emits light and is a light-emitting diode (LED). The power supplied to the light-emitting element 202 is supplied from an external power source (the battery of the gripping part 120) of the chestpiece 110. The light-emitting element 202 is mounted on a light-emitting circuit board 203. The light-emitting circuit board 203 is equipped with peripheral circuits for defining the amount of light emitted by the light-emitting element 202, and power terminals for receiving power from an external power source of the chestpiece 110.

[0019] The light-receiving element 204 generates an electrical signal based on the amount of light it receives, using power supplied from a battery housed inside the gripping section 120. The power supplied to the light-receiving element 204 is supplied from the battery in the gripping section 120. The light-receiving element 204 is, for example, a phototransistor or a complementary metal-oxide-semiconductor (CMOS) sensor. The light-receiving element 204 is mounted on a light-receiving circuit board 205. In addition to the light-receiving element 204, the light-receiving circuit board 205 is also equipped with peripheral circuits for reading signals from the light-receiving element 204, signal terminals for outputting signals to devices outside the chestpiece 110, and power terminals for receiving power from an external power source to the chestpiece 110.

[0020] The diaphragm 206 is held by a retaining member 201 and positioned to contact a biological surface. The diaphragm 206 has a contact surface 206a that contacts the biological surface and an inner surface 206b that is the opposite side of the contact surface 206a. The diaphragm 206 also has a fixed portion 206c that is fixed to the retaining member 201. The fixed portion 206c is located on the outer circumference of the diaphragm 206. The portion of the diaphragm 206 inside the fixed portion 206c is not fixed to the retaining member 201. Therefore, the diaphragm 206 undergoes elastic deformation upon receiving pressure from the object being measured that is in contact with the contact surface 206a. Specifically, the diaphragm 206 vibrates in the z-axis direction with the fixed portion 206c as a node. The inner surface 206b of the diaphragm 206 is provided with a light-reflecting portion 207, which will be described later. The diaphragm 206 is a laminate of glass epoxy resin, which is made by impregnating glass fibers with epoxy resin and then heat-curing it.

[0021] The light-reflecting portion 207 reflects light emitted from the light-emitting element 202. The light-reflecting portion 207 is bonded to the inner surface 206b of the diaphragm 206 and moves integrally with the diaphragm 206 in the z-axis direction in conjunction with the vibration of the diaphragm 206, which is in close contact with the biological surface. The light-reflecting portion 207 has a circular outer edge in the plan view. The light-reflecting portion 207 has a diameter of 15 mm to 20 mm and is positioned to cover the region 206d of the diaphragm 206 that includes the center 206e of the circle. Since the displacement of the diaphragm 206 changes most significantly at the center 206e, the displacement of the diaphragm 206 can be detected with high sensitivity by reflecting light from the light-emitting element 202 in the region including the center 206e. The light-reflecting portion 207 is made of, for example, an aluminum vapor-deposited film.

[0022] The light-emitting element 202 emits light toward the inner surface 206b of the diaphragm 206. The upper surface of the light-reflecting part 207 reflects the light emitted from the light-emitting element 202. That is, the upper surface of the light-reflecting part 207 functions as a light-reflecting surface. In the following description, the reflection of light at the upper surface (light-reflecting surface) of the light-reflecting part 207 will simply be referred to as "light being reflected by the light-reflecting part 207." The light-reflecting part 207 specularly reflects (in other words, mirror-reflects) the light emitted from the light-emitting element 202. In the following description, the light traveling from the light-emitting element 202 toward the light-reflecting part 207 will be referred to as incident light 211, and the light after the incident light 211 has been reflected will be referred to as reflected light 212.

[0023] The light-emitting element 202 is positioned to emit light toward a region 207a of the light-reflecting portion 207 that includes the portion covering the center 206e of the diaphragm 206, when the diaphragm 206 is not in contact with the biological surface. When the diaphragm 206 is not in contact with the biological surface, the diaphragm 206 is flat. The light-emitting element 202 emits light toward a specific region (for example, region 207a) of the light-reflecting portion 207. As described above, an LED that emits diffuse light is used as the light-emitting element 202. Therefore, the chestpiece 110 has a diaphragm portion 209 that narrows the light emitted from the light-emitting element 202. The diaphragm portion 209 ensures that only a portion of the light emitted from the light-emitting element 202 enters the light-reflecting portion 207. In the example in Figure 2, the portion of the holding member 201 with an opening corresponds to the diaphragm portion 209.

[0024] The light-receiving element 204 is positioned to receive reflected light 212. Specifically, the light-receiving element 204 is positioned so that the amount of reflected light 212 received changes due to the vibration of the diaphragm 206 in the z-axis direction. The light-receiving element 204 is positioned so that when the diaphragm 206 is not in contact with the biological surface (i.e., when the diaphragm 206 is flat), it receives more light in the reflected light 212 compared to when the diaphragm 206 is vibrating. That is, the light-receiving element 204 outputs an electrical signal corresponding to the amount of reflected light 212 it receives, and the amount of displacement of the diaphragm 206 can be determined based on this electrical signal. This principle will be described later. The chestpiece 110 has an aperture section 210 that narrows the light specularly reflected by the light-reflecting section 207. The aperture section 210 suppresses diffusely reflected light from entering the light-receiving element 204, and allows at least a portion of the light from the light-reflecting section 207 to reach the light-receiving element 204. In the example shown in Figure 2, the portion of the holding member 201 in which the opening is formed functions as the constricted portion 210.

[0025] A housing 208 is attached to the outer upper surface of the holding member 201. The housing 208 covers the light-emitting circuit board 203 and the light-receiving circuit board 205, and also suppresses ambient noise from entering the housing 208.

[0026] [Example of operation of the electronic stethoscope] An example of operation of the chestpiece 110 of the electronic stethoscope 100 will be described with reference to Figures 3A and 3B. As shown in Figures 3 and 3B, the chestpiece 110 is used in contact with the biological surface 300 to be measured. As a result, the biological surface 300, the diaphragm 206, and the light reflecting part 207 vibrate together. Therefore, the chestpiece 110 detects the displacement of the upper surface of the light reflecting part 207 in the z-axis direction as the displacement of the biological surface 300 in the z-axis direction. The displacement of the biological surface 300 occurs in response to bodily movements such as heartbeat and breathing of the person having the biological surface 300.

[0027] Figure 3A shows a cross-sectional view of the chestpiece 110 when the diaphragm 206 is flat. As described above, the light-emitting element 202 and the light-receiving element 204 are arranged so that when the diaphragm 206 is flat, more reflected light 212 is received by the light-receiving element 204 compared to when the diaphragm 206 is vibrating. The light-receiving element 204 amplifies and outputs a photocurrent corresponding to the amount of light it receives. The peripheral circuit of the light-receiving circuit board 205 generates an output value obtained by converting the photocurrent output from the light-receiving element 204 into a voltage, and outputs this displacement signal to an external device. The displacement signal refers to the output value of the light-receiving element 204 that reflects the state and deformation of the diaphragm 206 at any given time.

[0028] Figure 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 light-reflecting part 207 is represented by d1. When the biological surface 300 is displaced upward, the distance d1 decreases. Accordingly, the region 207a of the light-reflecting part 207 that the incident light 211 reaches moves closer to the light-emitting element 202, and the reflected light 212 also moves closer to the light-emitting element 202. As a result, the amount of reflected light 212 that reaches the photodetector 204 decreases, and the value of the displacement signal generated by the photodetector circuit board 205 becomes smaller. In the state shown in Figure 3B, since the reflected light 212 does not reach the photodetector 204 at all, the value of the displacement signal is ideally zero.

[0029] Thus, in the chestpiece 110, the light-emitting element 202 and the light-receiving element 204 are arranged such that the amount of light reaching the light-receiving element 204 changes in accordance with the movement of the biological surface 300, the diaphragm 206, and the light-reflecting part 207. Since the light-reflecting part 207 is displaced in conjunction with the displacement of the biological surface 300, the displacement signal generated by the light-receiving circuit board 205 represents the displacement of the biological surface 300.

[0030] [Relationship between diaphragm displacement and reflected light receiving position in electronic stethoscope] Referring to Figure 4, the relationship between the displacement of the biological surface 300, the incident angle of incident light 211, the incident angle of reflected light 212, and the displacement of the position where the light receiving element 204 receives the reflected light 212 will be explained. In Figure 4, position 401 indicates the reference position of the upper surface of the light reflecting part 207. The upper surface of the light reflecting part 207 when the diaphragm 206 is flat is taken as the reference position. Position 402 indicates the position where the upper surface of the light reflecting part 207 is displaced upward by a displacement amount d2 from position 401. Since the displacement amount d2 of the light reflecting part 207 is small, even when the upper surface of the light reflecting part 207 is at position 402, the upper surface of the light reflecting part 207 is considered to be flat.

[0031] In Figure 4, the optical axis 403 indicates the optical axis of the incident light 211. The angle of incidence of light emitted from the light-emitting element 202 and incident on the light-reflecting part 207 is represented by θ. The angle of incidence θ of the incident light 211 is determined by the angle between the optical axis 403 of the incident light 211 and the normal to the upper surface of the light-reflecting part 207. When the upper surface of the light-reflecting part 207 is at position 401, the optical axis of the reflected light 212 is defined as optical axis 404. When the upper surface of the light-reflecting part 207 is at position 402, the optical axis of the reflected light 212 is defined as optical axis 405. Since the incident light 211 is specularly reflected at the upper surface of the light-reflecting part 207, the angle of reflection of the reflected light 212 is also θ. Optical axes 404 and 405 are parallel to each other. Also, when the angle of incidence of the reflected light 212 to the photodetector 204 is φ, φ is 0°. When the upper surface of the light-reflecting portion 207 is displaced from position 401 to position 402, the displacement amount of the position where the light-receiving element 204 receives the reflected light 212 is denoted as d3. The displacement amount d3 may also be defined by the displacement amount from the position where the light-receiving element 204 receives light from the optical axis 404 to the position where the light-receiving element 204 receives light from the optical axis 405. In the following explanation, the ratio of the displacement amount d3 to the displacement amount d2 is denoted as the displacement magnification G. In this case, the relationship G = 2 × sinθ / cosφ …(Equation 1) holds. Therefore, even if the displacement amount d2 of the light-reflecting portion 207 is the same, the larger the incident angle θ, the larger the displacement magnification G, and the larger the incident angle φ, the larger the displacement magnification G.

[0032] Figure 4 illustrates the case where the incident angle φ is 0°. That is, the optical axes 404 and 405 are perpendicular to the light-receiving surface of the photodetector 204. In this case, equation 1 becomes G = 2 × sinθ …(equation 2). In other words, the larger the incident angle θ, the larger the displacement d3.

[0033] In the electronic stethoscope 100, as described above, an LED is used as the light-emitting element 202, and the displacement of the diaphragm 206 is measured based on the amount of light received by the light-receiving element 204. Alternatively, a laser beam may be used as the light-emitting element 202, and the displacement of the diaphragm 206 may be measured based on the position of the light received by the light-receiving element 204.

[0034] [Relationship between Displacement Amount and Displacement Signal of the Biological Surface of the Electronic Auscultation Device] The relationship between the displacement amount of the biological surface 300 and the displacement signal will be explained with reference to Figure 5. The displacement signal represents the voltage output from the light-receiving circuit board 205. Graph 500 in Figure 5 shows the relationship between the displacement amount of the biological surface 300 and the displacement signal. The horizontal axis of graph 500 represents the displacement amount of the biological surface 300 and represents the displacement signal generated by the light-receiving circuit board 205.

[0035] As described above, the displacement of the biological surface 300 is equal to the displacement d2 of the upper surface of the light reflecting part 207. As shown in Figures 3 and 3B, as the displacement d3 of the reflected light 212 increases, the amount of reflected light 212 that reaches the photodetector 204 decreases monotonically and linearly. Therefore, if we represent the value of the displacement signal as Sd, we get Sd = Vmax - k × d3 …(Equation 6). Here, Vmax is the value of the displacement signal when the displacement d3 of the reflected light 212 is zero, and k is a proportionality constant determined by the amplification factor of the amplification circuit of the photodetector circuit board 205. By substituting Equation 1 into Equation 6, we obtain Sd = Vmax - 2k × d2 × sinθ / cosφ …(Equation 7). Therefore, as shown in Graph 500, the displacement signal Sd decreases monotonically and linearly as the displacement d2 of the biological surface 300 increases. The displacement amount at which the displacement signal Sd becomes zero is denoted as dmax. When the displacement amount exceeds dmax, the reflected light 212 no longer reaches the photodetector 204, so even if the displacement amount d2 increases, the displacement signal Sd remains zero. Therefore, the proportionality constant k, the incident angle θ, and the incident angle φ are set so that the displacement amount d2 is in the range of 0 or more and dmax or less within the range in which the vibration of the diaphragm 206 is expected. As shown in graph 500, the light-emitting element 202 and the photodetector 204 are arranged so that the amount of light reaching the photodetector 204 changes monotonically in response to the movement of the light-reflecting part 207 in one direction within the operating range of the diaphragm 206.

[0036] In Equation 7, the coefficient of d2, 2k × sinθ / cosφ = k × G, represents the sensitivity of the chestpiece 110. The angle of incidence θ can take values ​​greater than 0° and less than 90°. The angle of incidence φ can take values ​​between 0° and less than 90°. The larger the displacement ratio G, the higher the sensitivity of the chestpiece 110. Therefore, the chestpiece 110 is configured such that the displacement ratio G is greater than 1, that is, the displacement amount d3 is greater than the displacement amount d2.

[0037] The chestpiece 110 can accurately detect the displacement of the biological surface 300. Specifically, in the chestpiece 110 described above, when the biological surface, which is an example of the object to be measured, is in close contact with the diaphragm 206, a displacement signal is generated based on the amount of displacement d2 of the biological surface that vibrates together with the diaphragm 206. Therefore, the displacement of the biological surface 300 can be accurately detected regardless of the frequency at which the biological surface 300 vibrates. For example, even displacement of the biological surface 300 due to low-frequency vibrations of about 10 Hz can be accurately detected. Such low-frequency vibrations are included in sounds (e.g., heart sounds) emitted by vibrations propagated from inside the body by the heartbeat. In the chestpiece 110, the displacement signal does not change unless the diaphragm 206 is displaced. Therefore, ambient sound and vibrations or accelerations due to the movement of the chestpiece 110 are not detected as noise, resulting in output characteristics with a high signal-to-noise ratio.

[0038] [Example of Circuit Configuration of Electronic Auscultation Device] An example of the circuit configuration of the electronic auscultation device 100 will be described with reference to Figure 6. The microcontroller 600 is a control means that controls the overall operation of the electronic auscultation device 100. In Figure 6, the electronic auscultation device 100 includes one microcontroller 600. Alternatively, the electronic auscultation device 100 may include multiple microcontrollers 600. The microcontroller 600 includes a processor 601, a non-volatile memory 602, a Bluetooth® circuit 603, and a RAM 604. The processor 601 controls the operation of the electronic auscultation device 100 by executing a program stored in the non-volatile memory 602. The non-volatile memory 602 is a storage device for storing a program that defines the operation of the electronic auscultation device 100 and various setting data, and maintains its contents even without external power supply. The Bluetooth circuit 603 is a control unit that controls a wireless communication unit 618 that conforms to the Bluetooth wireless communication standard. The wireless communication unit 618 includes an antenna for wireless communication. In Figure 6, the microcontroller 600 has a built-in Bluetooth circuit 603, but the Bluetooth circuit 603 may be located outside the microcontroller 600. The RAM 604 is a memory device that temporarily stores programs and various setting data read from the non-volatile memory 602.

[0039] The microcontroller 600 is implemented by multiple circuit elements mounted on a circuit board included in the gripping unit 120. The microcontroller 600 transmits an audio signal based on the displacement signal generated by the light-receiving element 204 to an external audio output device 670 via a wireless communication unit 618 or a wired communication unit 617. The audio output device 670 is, for example, a wired or wireless earphone or headphones. In addition to transmitting audio signal data to the audio output device 670, the microcontroller 600 can also transmit audio signal data to a computer 680 (for example, a personal computer, smartphone, tablet, etc.). Doctors, nurses, and public health nurses can use the audio output device 670 or the computer 680 to hear the biological sounds represented by the audio signals converted from the audio signal data.

[0040] The displacement signal output from the light-receiving element 204 is filtered and amplified by the displacement signal processing unit 630 (described later) and supplied to the A / D converter 605. The A / D converter 605 digitizes the output from the displacement signal processing unit 630. The digital displacement signal is then converted by the microcontroller 600 to, for example, the Pulse Code Modulation (PCM) format, and then processed by an encoder, such as data compression and encoding, according to the format compliant with the communication standard, and converted into sound signal data for wireless communication. The wireless communication unit 618 then transmits the sound signal data to the sound output device 670. The sound output device 670, upon receiving the sound signal data, outputs a sound corresponding to that sound signal data.

[0041] Although the above-described electronic stethoscope 100 is shown as being capable of transmitting sound signal data via both wireless and wired communication, it may also be capable of transmitting sound signal data via only one of these communication methods. Transmitting sound signal data to the computer 680 is the same as transmitting sound signal data to the sound output device 670. The computer 680 can also visually display waveform data generated based on the received sound signal data. The waveform data may be generated by the computer 680 or by the electronic stethoscope 100. Furthermore, some or all of the signal processing and sound output processing by the electronic stethoscope 100 may be performed by an external device (for example, the sound output device 670 or the computer 680).

[0042] The UART integrated circuit 620 is connected to the microcontroller 600 and to the connector 125 (specifically, its data terminals). The UART integrated circuit 620 performs UART-compliant communication. The UART integrated circuit 620 and the connector 125 function as a wired communication unit 617. The microcontroller 600 may communicate with external devices via wires through the UART integrated circuit 620 and the connector 125. The UART integrated circuit 620 may also be connected to the power terminals of the connector 125. A voltage VBUS may be applied to the UART integrated circuit 620 through the power terminals of the connector 125 from an external device connected to the connector 125 (e.g., a charger or a computer 680). The UART integrated circuit 620 may be able to operate with the voltage VBUS as its operating voltage.

[0043] The power supply unit 610 includes a battery 611, a charging integrated circuit 612, a boost converter 613, a voltage regulator 614, a load switch 615, and a voltage regulator 616. The power supply unit 610 supplies power to multiple circuit elements included in the electronic stethoscope 100. The power supply unit 610 may supply power at multiple different voltages. Alternatively, the power supply unit 610 may supply power at a single voltage, and the voltage may be reduced in front of each circuit element to obtain an appropriate operating voltage.

[0044] The battery 611 stores the electrical energy used in the electronic stethoscope 100. The battery 611 may have a function of interrupting the current flowing through the battery 611 when the current exceeds a threshold value. The charge integrated circuit 612 is an integrated circuit (IC) that controls the charging of the battery 611 and the discharging from the battery 611. For example, the charge integrated circuit 612 charges the battery 611 using the electrical energy supplied from an external device such as a charger or a computer 680 connected to the connector 125. Also, the charge integrated circuit 612 supplies the electrical energy stored in the battery 611 to the boost converter 613. The voltage provided by the charge integrated circuit 612 is represented as voltage VBAT. The voltage VBAT is, for example, 3.7V.

[0045] The boost converter 613 boosts a DC voltage to a DC voltage of another value. The boost converter 613 is also called a DC / DC converter. The boost converter 613 boosts the voltage VBAT supplied from the charge integrated circuit 612 to the voltage V0. The voltage V0 is, for example, 6.8V. The voltage regulator 614 generates and outputs a voltage of a specific value. The voltage regulator 614 may be a linear regulator and is also called a low dropout regulator (LDO). The voltage regulator 614 generates the operating voltage of some circuit elements of the electronic stethoscope 100. The voltage generated by the voltage regulator 614 is represented as voltage V1. The voltage regulator 614 may generate the operating voltage of the microcontroller 600. For example, the voltage V1 is 3.3V. Also, the operating voltage of the acceleration sensor 650 is also the voltage V1. In the example of FIG. 6, the voltage V1 is applied to each of the microcontroller 600 and the acceleration sensor 650. Power is supplied to the microcontroller 600 and the acceleration sensor 650 from the voltage regulator 614 of the power supply unit 610. The voltage regulator 614 outputs the voltage V1 when a voltage higher than the voltage V1 is also applied to its input terminal. Therefore, the voltage regulator 614 outputs the voltage V1 when the voltage V0 is supplied from the boost converter 613.

[0046] The load switch 615 is a switch that switches between on (conductive state) and off (non-conductive state) in response to a control signal from the microcontroller 600. The voltage regulator 616 generates and outputs a voltage of a specific value. The voltage regulator 616 may be a linear regulator or an LDO. The voltage regulator 616 generates the operating voltage for some of the circuit elements of the electronic stethoscope 100. The voltage generated by the voltage regulator 616 is denoted as voltage V2. The voltage regulator 616 may also generate the operating voltage for the light-emitting element 202 and the light-receiving element 204, for example, voltage V2 is 5.8V. In the example in Figure 6, voltage V2 is applied to the light-emitting element 202 and the light-receiving element 204, respectively. Power is supplied to the light-emitting element 202 and the light-receiving element 204 from the voltage regulator 616 of the power supply unit 610. The voltage regulator 616 outputs voltage V2 when a high voltage V2 is applied to its input terminal. Therefore, the voltage regulator 616 outputs voltage V2 when the load switch 615 is ON. The voltage regulator 616 does not output voltage V2 when the load switch 615 is OFF. When the voltage regulator 616 does not output voltage V2, the potential of the output terminal of the voltage regulator 616 is ground potential.

[0047] The displacement signal processing unit 630 generates a sound signal representing the sound transmitted from the living body surface to the diaphragm 206 by processing the diaphragm displacement signal, and outputs this sound signal to the microcontroller 600. Specifically, the displacement signal processing unit 630 extracts components in a specific frequency band included in the diaphragm displacement signal and generates a sound signal. As will be described later, the components in the specific frequency band to be extracted include components in the frequency band ranging from 10 Hz to 1 kHz. The diaphragm displacement signal is a signal generated and output by the light receiving element 204 according to the amount of light reaching the light receiving element 204. Hereinafter, the diaphragm displacement signal is simply referred to as a displacement signal. The amount of light reaching the light receiving element 204 changes according to the displacement of the diaphragm 206. When the light emitting element 202 is a laser diode that emits laser light as described above, the displacement signal may be a signal generated and output by the light receiving element 204 according to the position of the light reaching the light receiving element 204. Even when realized by a laser diode, the displacement signal still represents the displacement of the diaphragm 206. The heart sound signal is also a kind of displacement signal because it represents the displacement of the diaphragm 206 (specifically, the components in its specific frequency band).

[0048] The displacement signal processing unit 630 includes a buffer circuit 631, a high-pass filter (HPF) 632, and amplifier circuits 633 and 634 with low-pass filters on the signal path between the light receiving element 204 and the microcontroller 600. These circuit elements are connected in series. The displacement signal processing unit 630 receives the displacement signal from the light receiving element 204 and outputs the sound signal to the microcontroller 600.

[0049] The buffer circuit 631 receives the displacement signal from the light receiving element 204 and outputs the displacement signal to the HPF 632. The buffer circuit 631 performs impedance conversion of the signal path between the light receiving element 204 and the HPF 632. For example, the output impedance of the buffer circuit 631 is lower than the output impedance of the light receiving element 204. The operating power of the buffer circuit 631 is supplied from the voltage regulator 616.

[0050] The HPF 632 outputs a signal to the amplifier 633 obtained by attenuating the low-frequency components (i.e., frequency components lower than a specific cutoff frequency) of the displacement signal received from the buffer circuit 631 and passing the high-frequency components (i.e., frequency components higher than the said cutoff frequency) of the displacement signal. The HPF 632 attenuates components below 10 Hz from the displacement signal received from the buffer circuit 631, so the cutoff frequency of the HPF 632 is set to, for example, 10 Hz. However, the cutoff frequency may be a value greater than 10 Hz, for example, 15 Hz or 20 Hz. Also, the cutoff frequency may be 10 Hz or more and less than 20 Hz. Therefore, the HPF 632 removes or attenuates components below 10 Hz from the displacement signal received from the buffer circuit 631.

[0051] The HPF632 is placed on the signal path between the photodetector 204 and the microcontroller 600 to remove or attenuate low-frequency noise contained in the displacement signal. The low-frequency noise contained in the displacement signal is a component that does not originate from vibrations transmitted from the biological surface to the diaphragm 206. For example, the low-frequency noise may include a component caused by the user's hand tremors when using the electronic stethoscope 100. The low-frequency noise may also include a change in the DC component due to the diaphragm 206 being pressed against the biological surface. Such low-frequency noise has a much larger amplitude than the component originating from vibrations transmitted from the biological surface to the diaphragm 206 (hereinafter referred to as the biological component). Therefore, by amplifying the displacement signal from which the low-frequency noise has been suppressed, the biological component can be appropriately acquired within the dynamic range of the amplification circuit. Alternatively, a bandpass filter that removes components below at least 10 Hz may be used instead of the HPF632.

[0052] [Example of Functional Configuration of an Electronic Auscultation Device] Referring to Figure 7, the functional blocks implemented by the processor 601 of the microcontroller 600 will be described. Each functional block in Figure 7 is implemented by the processor 601 loading a program stored in the non-volatile memory 602 into the RAM 604 and executing it. However, some or all of the functional blocks in Figure 7 may be implemented by a dedicated integrated circuit such as an application-specific integrated circuit (ASIC).

[0053] The motion detection unit 701 detects the movement of the electronic stethoscope 100 based on the acceleration signal acquired from the acceleration sensor 650. For example, the motion detection unit 701 determines that the electronic stethoscope 100 is moving if the acceleration in at least one of the three axes (x, y, and z) is not zero or exceeds a threshold. Conversely, the motion detection unit 701 determines that the electronic stethoscope 100 is stationary if the acceleration in all axes is zero or below a threshold.

[0054] The display control unit 702 controls the display of the display unit 122. The input acquisition unit 703 acquires user input using the operation unit 123 and the power switch 124. The power management unit 704 controls the operation of the power supply unit 610, for example, the operation of generating a specific voltage. Specifically, the power management unit 704 switches the level of the control signal supplied to the load switch 615, and switches the load switch 615 on and off. As described above, when the load switch 615 is turned off, voltage V0 is no longer supplied to the voltage regulator 616, so the power supply from the voltage regulator 616 is stopped, and the system switches to power saving mode.

[0055] The pressure detection unit 705 detects that the diaphragm 206 is being pressed or in contact with something based on the displacement signal acquired from the displacement signal processing unit 630. Hereinafter, the pressing state of the diaphragm 206 will be simply referred to as the pressing state. For example, the pressure detection unit 705 can identify which of several states the pressing state is. Specifically, the pressure detection unit 705 can identify whether the pressing state is in use or not. The not-use state is the pressing state when the user is not pressing the diaphragm 206 in close contact with the biological surface. The use state is the pressing state when the user is pressing the diaphragm 206 in close contact with the biological surface. In other words, the pressing state can also be described as the state in which the diaphragm 206 is being pressed by a biological body with a force greater than a predetermined amount, and the diaphragm 206 is being displaced by a predetermined amount. The amount of displacement of the diaphragm 206 in the not-use state is smaller than the amount of displacement of the diaphragm 206 in the use state. Therefore, the pressure detection unit 705 determines that the pressing state is in a non-use state if the amount of displacement of the diaphragm 206, which is identified from the displacement signal, is less than a threshold. On the other hand, the pressure detection unit 705 determines that the pressing state is in use if the amount of displacement of the diaphragm 206 exceeds the threshold.

[0056] The output control unit 706 transmits the sound signal acquired from the displacement signal processing unit 630 to an external device such as a computer 680 or a sound output device 670 via the wireless communication unit 618 or the wired communication unit 617. The output control unit 706 configures the electronic stethoscope 100 based on whether it is in heartbeat sound mode or respiratory sound mode. For example, the output control unit 706 configures at least one of the following based on whether the electronic stethoscope 100 is in heartbeat sound mode or respiratory sound mode: the sensitivity of the light-receiving element 204, the cutoff frequency of the HPF 632, and the amplification factor of the amplification circuits 633 and 634. The sound signal output from the output control unit 706 when the electronic stethoscope 100 is in heartbeat sound mode is referred to as the heartbeat sound signal. The sound signal output from the output control unit 706 when the electronic stethoscope 100 is in respiratory sound mode is referred to as the respiratory sound signal.

[0057] The output control unit 706 performs signal processing on the sound signal before outputting it. Specifically, the output control unit 706 includes a reduction processing unit 711 and a smoothing processing unit 712. The reduction processing unit 711 performs a reduction process that compares the amplitude of the sound signal with a threshold amplitude and reduces the amplitude that exceeds the threshold amplitude. The smoothing processing unit 712 performs a smoothing process that removes components above the cutoff frequency (i.e., high-frequency components) from the sound signal after the reduction process.

[0058] The volume control unit 707 adjusts the volume of the sound signal (heartbeat sound signal or respiratory sound signal) output to the outside. Hereinafter, the volume of the sound signal output to the outside may be simply referred to as volume. For example, the volume control unit 707 adjusts the volume based on user input acquired by the input acquisition unit 703. For example, the volume control unit 707 increases the volume when the volume up button 123a included in the operation unit 123 of Figure 1 is operated by the user and instructs them to increase the volume. The volume control unit 707 decreases the volume when the volume down button 123b included in the operation unit 123 of Figure 1 is operated by the user and instructs them to decrease the volume.

[0059] The volume control unit 707 also adjusts the volume based on the pressing state. For example, the volume control unit 707 can set the volume to a normal level when the diaphragm 206 is pressed above a certain level by the object being measured (i.e., when it is determined to be in use). The operation of setting the volume based on the pressing state will be described later. The normal level volume is a volume suitable for listening to the sound signal reproduced by the sound output device 670. The volume control unit 707 adjusts the normal level value based on the user input acquired by the input acquisition unit 703.

[0060] The volume control unit 707 sets the volume to the mute level when the diaphragm 206 is not being pressed by the object being measured (i.e., it is determined to be in an unused state). The mute level volume means a volume that is zero or lower than the normal level volume. For example, the mute level volume may be so low that it is not suitable for listening to the sound signal reproduced by the sound output device 670. The mute level can also be a constant multiple of the normal level (e.g., 10%). When the mute level is configured to depend on the normal level in this way, if the normal level changes due to user input via the volume control buttons included in the operation unit 123, for example, the mute level will also change depending on the normal level. On the other hand, the mute level can also be set independently of the normal level. When the mute level is independent of the normal level, even if the normal level changes due to user input, for example, the mute level will not change.

[0061] The volume control unit 707 adjusts the volume level of the sound signal by adjusting the gain of at least one of the amplification circuits 633 and 634. Alternatively, the volume control unit 707 may adjust the volume level of the sound signal by adjusting the digital value of the sound signal output to the outside by the output control unit 706.

[0062] [Example of Computer Hardware Configuration] Referring to Figure 8, an example of the hardware configuration of computer 680 will be described. Computer 680 has the components shown in Figure 8. Computer 680 is sometimes called an information processing device or an information processing terminal. Processor 801 controls the overall operation of computer 680. Processor 801 may be composed of, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microcontroller (e.g., a single-chip microcontroller), or a combination thereof. Processor 801 may be a single processor, or a collection of multiple processors connected to each other in a communicative manner.

[0063] Memory 802 is a storage device that stores programs and data used for processing by the computer 680. Memory 802 may be configured, for example, by a combination of random access memory (RAM) and read-only memory (ROM).

[0064] The input device 803 is a device for obtaining instructions from the user of the computer 680. The input device 803 may consist of one or more combinations of, for example, a keyboard, buttons, a touchpad, and a microphone. The display device 804 is a device for visually presenting information to the user of the computer 680. The display device 804 may be a dot-matrix display such as a liquid crystal display or an OLED (Organic Light-Emitting Diode) display. The computer 680 may have a device in which the input device 803 and the display device 804 are integrated (for example, a touchscreen). The input device 803 and the display device 804 may be located outside the computer 680. In this case, the computer 680 may have an interface for communicating with the external input device 803 and the display device 804. Regardless of whether the input device 803 is located outside or inside the computer 680, the input device 803 used to obtain input to the computer 680 is referred to as the input device 803 of the computer 680. The same applies to the display device 804 and the secondary storage device 806.

[0065] The communication device 805 is a device for communicating with an external device (e.g., an electronic stethoscope 100) of the computer 680. When the computer 680 uses wired communication, the communication device 805 is a network interface card (NIC) having connectors for connecting cables. When the computer 680 uses wireless communication, the communication device 805 is a wireless communication module including an antenna and baseband processing circuitry. The communication device 805 can communicate with the electronic stethoscope 100 using the Bluetooth standard. Alternatively, the communication device 805 may include a WLAN interface, a cellular communication interface, or a USB interface.

[0066] The secondary storage device 806 is a storage device for non-volatilely storing programs and data used in the processing of the computer 680. The secondary storage device 806 is composed of, for example, a hard disk drive (HDD) or a solid-state drive (SSD). The secondary storage device 806 stores sound signal data received from the electronic stethoscope 100. The secondary storage device 806 stores the sound signal data as an audio file.

[0067] The secondary storage device 806 has a linkage application 807 installed for linking with the electronic stethoscope 100. The linkage application 807 may be a dedicated application for linking with the electronic stethoscope 100. Alternatively, if the electronic stethoscope 100 has a web server function, the linkage application 807 may be a web browser. The linkage application 807 is read into memory 802 and executed by the processor 801.

[0068] [Screen provided by the linked application] An example of a screen 900 provided by the linked application 807 will be described with reference to Figure 9. The screen 900 is displayed on the display device 804. The screen 900 includes a setting area 910 on which objects related to the settings of the electronic stethoscope 100 are arranged, and a display area 920 on which objects related to the display of sound signal data received from the electronic stethoscope 100 are arranged.

[0069] The setting area 910 includes objects 911 to 913, a pairing button 914, and a setting update button 915. Object 911 is an object for obtaining the user's specification of the operating mode of the electronic stethoscope 100. On screen 900, the user can selectively choose between heart sound mode and respiratory sound mode. Object 912 is an object for obtaining the user's specification of the method for controlling the volume of the sound signal data output by the electronic stethoscope 100. If "fade in" is specified in object 912, the volume will fade in. Specifically, the electronic stethoscope 100 starts outputting sound signal data at a mute level volume (e.g., 0%) and then gradually increases the volume to a normal level (e.g., 100%). If "none" is specified in object 912, the electronic stethoscope 100 will not fade in the volume.

[0070] Object 913 is an object for obtaining from the user the location where sound signal data output by the electronic stethoscope 100 will be stored. On screen 900, the user can choose between the computer 680 and the electronic stethoscope 100 as the storage location for the sound signal data. If the electronic stethoscope 100 is selected as the storage location for the sound signal data, the electronic stethoscope 100 stores the sound signal data in the non-volatile memory 602. The sound signal data stored in the non-volatile memory 602 may then be read by the computer 680 or other devices. If the computer 680 is selected as the storage location for the sound signal data, the electronic stethoscope 100 sends the sound signal data to the computer 680, and the linked application 807 stores this sound signal data in the secondary storage device 806.

[0071] The pairing button 914 is a button for obtaining instructions from the user to perform pairing between the electronic stethoscope 100 and the computer 680. The collaborative application 807 starts pairing with the electronic stethoscope 100 in response to the user pressing the pairing button 914. The setting update button 915 is a button for obtaining instructions from the user to reflect the settings specified in objects 911 to 913 to the electronic stethoscope 100. The collaborative application 807 sends the settings specified in objects 911 to 913 to the electronic stethoscope 100 in response to the user pressing the setting update button 915. The electronic stethoscope 100 stores these settings in the non-volatile memory 602 and operates according to these settings. The setting update button 915 may be omitted, in which case the collaborative application 807 sends new settings to the electronic stethoscope 100 each time the settings are changed in objects 911 to 913.

[0072] The display area 920 includes a display field 921 and an object 922. The display field 921 displays sound signal data received from the electronic stethoscope 100. The linked application 807 updates the display content of the display field 921 as the value of the sound signal data received from the electronic stethoscope 100 is updated. Object 922 is an object for obtaining the user's specification of the display format for the sound signal data in the display field 921. The linked application 807 converts the sound signal data to the display format specified by object 922 and displays it in the display field 921. For example, if "waveform" is selected in object 922, the linked application 807 displays a waveform with time on the horizontal axis. If "spectrum" or "spectrogram" is selected in object 922, the linked application 807 displays the intensity of each frequency component. In addition to displaying the sound signal data in the display field 921, the linked application 807 may also output the sound represented by the sound signal data as an audible output.

[0073] [Storage of sound signal data] A method for performing the storage of sound signal data will be described with reference to Figure 10. Each step of the method in Figure 10 is realized by the processor 601 executing a program stored in the non-volatile memory 602. However, some or all of the steps of the method in Figure 10 may be realized by a dedicated integrated circuit. The processor 601 starts the method in Figure 10 when the power of the electronic stethoscope 100 is turned on and ends the method in Figure 10 when the power of the electronic stethoscope 100 is turned off. Alternatively, the processor 601 may start the method in Figure 10 when the electronic stethoscope 100 transitions from power-saving mode to another mode (for example, heart sound mode or respiratory sound mode) and end the method in Figure 10 when the electronic stethoscope 100 transitions to power-saving mode.

[0074] In S1001, the processor 601 (for example, the output control unit 706) determines whether it has received a standby start instruction from the user. If the processor 601 determines that it has received a standby start instruction from the user (YES in S1001), it proceeds to S1002; otherwise (NO in S1001), it repeats S1001. In this way, the processor 601 waits for a standby start instruction from the user. A standby start instruction is an instruction to wait for the start of the save process. The state in which the electronic stethoscope 100 is waiting for the start of the save process is referred to as the standby state. The electronic stethoscope 100 enters the standby state in response to receiving a standby start instruction.

[0075] The processor 601 considers a long press (for example, for 1 second or more) of the mode switching button 123c on the control unit 123 by the user while the electronic stethoscope 100 is not in standby mode as a standby start instruction. Alternatively, the control unit 123 may include a dedicated button for obtaining a standby start instruction. In addition to or instead of instructions using the control unit 123, the processor 601 may obtain a standby start instruction from the computer 680 using the wireless communication unit 618 or the wired communication unit 617. For example, the screen 900 displayed by the collaborative application 807 includes a button for obtaining a standby start instruction from the user, and when this button is pressed by the user, the collaborative application 807 sends a standby start instruction to the electronic stethoscope 100.

[0076] In S1002, the processor 601 (for example, the pressure detection unit 705) determines whether the biological surface 300 has started pressing the diaphragm 206. Specifically, the processor 601 determines that the biological surface 300 has started pressing the diaphragm 206 based on the detection of pressure on the diaphragm 206 by the biological surface 300. If the processor 601 determines that the biological surface 300 has started pressing the diaphragm 206 (YES in S1002), it proceeds to S1003; otherwise, it repeats S1002 (NO in S1002). In this way, the processor 601 waits for the biological surface 300 to start pressing the diaphragm 206.

[0077] In S1003, in response to the commencement of pressing of the diaphragm 206 by the biological surface 300 while the electronic stethoscope 100 is in standby mode, the processor 601 (for example, the output control unit 706) starts saving processing. Saving processing is the process of saving sound signal data. When the electronic stethoscope 100 is set as the save destination, saving processing includes writing the sound signal data generated based on the displacement signal to the non-volatile memory 602. Specifically, the processor 601 opens a new file and starts writing sound signal data to this file. The processor 601 appends each new portion of the sound signal data to the file as it is generated.

[0078] If computer 680 is set as the save destination, the save process includes sending the sound signal data generated based on the displacement signal to computer 680. The cooperating application 807 on computer 680 writes the sound signal data received from the electronic stethoscope 100 to memory 802. Specifically, processor 601 opens a new file and starts writing sound signal data to this file. Each time a new portion of the sound signal data is generated, processor 601 sends this portion to computer 680. The cooperating application 807 appends the new portion of the sound signal data received from electronic stethoscope 100 to the file.

[0079] If the volume of the sound signal data is set to fade in, the processor 601 (for example, the output control unit 706) increases the volume of the sound signal data being saved from a mute level to a normal level. Specifically, the processor 601 sets the volume of the sound signal data to a mute level in response to the start of pressing of the diaphragm 206 by the biological surface 300 while the electronic stethoscope 100 is in a standby state. Then, the processor 601 increases the volume over a predetermined time (for example, 0.5 seconds) until it reaches a normal level. If the volume of the sound signal data is not set to fade in, the processor 601 sets the volume of the sound signal data being saved to a normal level from the beginning.

[0080] In S1004, the processor 601 (for example, the pressure detection unit 705) determines whether the pressing of the diaphragm 206 by the biological surface 300 has ended. Specifically, the processor 601 determines that the pressing of the diaphragm 206 by the biological surface 300 has ended based on the fact that the pressing of the diaphragm 206 by the biological surface 300 is no longer detected. If the processor 601 determines that the pressing of the diaphragm 206 by the biological surface 300 has ended (YES in S1004), it proceeds to S1005; otherwise (NO in S1004), it repeats S1004. In this way, the processor 601 waits for the pressing of the diaphragm 206 by the biological surface 300 to end. While S1004 is being repeated, sound signal data continues to be written to the non-volatile memory 602 or memory 802.

[0081] In S1005, in response to the completion of pressing the diaphragm 206, the processor 601 (for example, the output control unit 706) terminates the save process. If the electronic stethoscope 100 is set as the save destination, the processor 601 finishes writing the sound signal data to the file in the non-volatile memory 602 and closes the file. The save process saves the sound signal data as an audio file in the non-volatile memory 602. If the computer 680 is set as the save destination, the processor 601 finishes transmitting the sound signal data to the computer 680. The computer 680's collaborative application 807 finishes writing the sound signal data to the file in memory 802 and closes the file in response to the electronic stethoscope 100 no longer transmitting sound signal data. The save process saves the sound signal data as an audio file in memory 802. The collaborative application 807 may move this file from memory 802 to the secondary storage device 806.

[0082] Processor 601 or processor 801 assigns a file name according to a predetermined rule. For example, the file name is a predetermined string with a timestamp added. Processor 601 or processor 801 may also assign the following information as attribute information to the saved file. This information may be obtained from the user of the electronic stethoscope 100 or from a medical information server.

[0083]

[0084] In S1006, the processor 601 (for example, the output control unit 706) determines whether it has received a standby termination instruction from the user. If the processor 601 determines that it has received a standby termination instruction from the user (YES in S1006), it transitions to S1001; otherwise (NO in S1006), it transitions to S1002. In this way, the processor 601 waits for the biological surface 300 to press on the diaphragm 206 during the standby state. A standby termination instruction is an instruction to terminate the standby state. The electronic stethoscope 100 terminates the standby state in response to receiving a standby termination instruction.

[0085] The processor 601 considers a long press (for example, for 1 second or more) of the mode switching button 123c on the control unit 123 by the user while the electronic stethoscope 100 is in standby mode as a standby end instruction. Alternatively, the control unit 123 may include a dedicated button for obtaining a standby end instruction. In addition to or instead of instructions using the control unit 123, the processor 601 may obtain a standby end instruction from the computer 680 using the wireless communication unit 618 or the wired communication unit 617. For example, the screen 900 displayed by the collaborative application 807 includes a button for obtaining a standby end instruction from the user, and when this button is pressed by the user, the collaborative application 807 sends a standby start instruction to the electronic stethoscope 100. The button for obtaining a standby start instruction and the button for obtaining a standby end instruction may be integrated. In this case, each time the integrated button is pressed, the system switches between standby and non-standby states.

[0086] In the method described above, the electronic stethoscope 100 enters a standby state in response to the user's standby start command. Alternatively, the electronic stethoscope 100 may enter a standby state without the user's standby start command. For example, the electronic stethoscope 100 may always be in a standby state while operating in heart sound mode or respiratory sound mode. In this case, steps S1001 and S1006 in Figure 10 are omitted.

[0087] [Cooperation between the electronic stethoscope and the computer] An example of the operation in which the electronic stethoscope 100 and the computer 680 cooperate will be described with reference to Figure 11. In the operation example in Figure 11, the electronic stethoscope 100 and the computer 680 communicate in accordance with the Bluetooth standard. In the operation example in Figure 11, the user of the electronic stethoscope 100 sets up the electronic stethoscope 100 using the computer 680, and then presses the electronic stethoscope 100 against the biological surface 300. The operation of the computer 680 is defined by the cooperation application 807 and executed by the processor 801. The operation of the electronic stethoscope 100 is defined by a program stored in the non-volatile memory 602 and executed by the processor 601.

[0088] In S1101, the computer 680 displays the screen 900 and detects that the user has pressed the pairing button 914. In response, the computer 680 searches for an electronic stethoscope that can be paired according to the Bluetooth standard and finds the electronic stethoscope 100. At this stage, none of the items in objects 911 to 913 on the screen 900 are selected, and no data is displayed in the display field 921. In S1102, the computer 680 sends a pairing request to the discovered electronic stethoscope 100. In S1103, the electronic stethoscope 100, upon receiving the pairing request, sends a pairing permission to the computer 680, provided that it is not currently pairing with another device. This establishes a connection between the electronic stethoscope 100 and the computer 680. The electronic stethoscope 100 may transition to a waiting state for saving processing upon establishing a connection with the computer 680.

[0089] In S1104, the computer 680 requests the electronic stethoscope 100 to provide its current settings. These settings include the operating mode, volume control, and storage location. In S1105, the electronic stethoscope 100 provides its current settings to the computer 680. The computer 680 reflects the settings provided by the electronic stethoscope 100 in objects 911 to 913 on the screen 900. In the following, it is assumed that the computer 680 is specified as the storage location for the sound signal data.

[0090] In S1106, the computer 680 obtains the user's settings for the electronic stethoscope 100 using objects 911 to 913. In S1107, the computer 680 transmits the settings specified by objects 911 to 913 to the electronic stethoscope 100 in response to the user pressing the setting update button 915. In S1108, the electronic stethoscope 100 stores the settings received from the computer 680 as the current settings in the non-volatile memory 602.

[0091] In S1109, the electronic stethoscope 100 detects that the biological surface 300 has begun pressing on the diaphragm 206. In S1110, the electronic stethoscope 100 starts saving sound signal data. Specifically, the electronic stethoscope 100 generates sound signal data based on the displacement signal and starts transmitting the sound signal data to the computer 680. In S1111, the computer 680 converts the sound signal data received from the electronic stethoscope 100 into an image in the display format specified by object 922 and displays it in the display field 921. The computer 680 also starts writing the sound signal data received from the electronic stethoscope 100 to memory 802. While the diaphragm 206 is being pressed by the biological surface 300, the displacement signal is updated based on the amount of displacement of the diaphragm 206, and the sound signal data is also updated. The electronic stethoscope 100 continues to transmit the updated sound signal data to the computer 680, and the computer 680 continues to display and write the updated sound signal data.

[0092] In S1112, the electronic stethoscope 100 detects that the pressing of the diaphragm 206 by the biological surface 300 has ended. In S1113, the electronic stethoscope 100 terminates the process of saving the sound signal data. Specifically, the electronic stethoscope 100 terminates the transmission of sound signal data to the computer 680. In S1114, the computer 680 saves the sound signal data that has been written to the memory 802 so far as an audio file. The audio file format may be, for example, uncompressed WAV format, lossless compressed FLAC format, or lossy compressed mp3 format.

[0093] [Examples of saved sound signal data] Examples of saved sound signal data will be explained with reference to Figures 12 to 14. Figure 12 illustrates a comparative example in which the saving of sound signal data is started and stopped by the user operating a button on the electronic stethoscope. At time t1, the user operates a button on the electronic stethoscope, instructing the start of saving sound signal data, and the sound signal data saving process begins. At this time, noise caused by the button operation is generated in the sound signal data. At time t2, the user presses the electronic stethoscope against the body surface. At this time, noise caused by contact with the body surface is generated in the sound signal data. Subsequently, heart sounds are measured.

[0094] At time t3, the user removes the electronic stethoscope from the biological surface. At this time, noise is generated in the sound signal data due to the cessation of contact with the biological surface. At time t4, the user operates a button on the electronic stethoscope, instructing the end of saving the sound signal data, and the sound signal data saving process ends. At this time, noise is generated in the sound signal data due to the operation of the button. In the example in Figure 12, the sound signal data from times t1 to t4 is saved and contains various noises. Furthermore, the saved sound signal data also includes extraneous portions from periods when biological sounds cannot be detected (times t1 to t2 and t3 to t4). Thus, the quality of the sound signal data saved in the example in Figure 12 is low.

[0095] Figure 13 illustrates the sound signal data saved using the method shown in Figure 10 when fade-in is not set as volume control. Assume that the electronic stethoscope 100 is in standby mode before time t5. At time t5, the electronic stethoscope 100 determines that the pressing of the diaphragm 206 by the biological surface 300 has begun, based on the displacement signal falling below threshold Th1, and starts saving the sound signal data. At time t6, the electronic stethoscope 100 determines that the pressing of the diaphragm 206 by the biological surface 300 has ended, based on the displacement signal exceeding threshold Th1, and ends the saving of the sound signal data. In the example in Figure 13, sound signal data from time t5 to t6 is saved. Therefore, the saved sound signal data does not include noise that occurred before time t5 or after time t6. Furthermore, the saved sound signal data does not include extraneous parts that cannot be detected as biological sounds. Thus, in the example in Figure 13, high-quality sound signal data is saved.

[0096] Figure 14 illustrates the sound signal data saved using the method shown in Figure 10 when fade-in is set as the volume control. Assume that the electronic stethoscope 100 is in standby mode before time t5. At time t5, the electronic stethoscope 100 determines that the pressing of the diaphragm 206 by the biological surface 300 has begun, based on the displacement signal falling below threshold Th1, and begins increasing the volume from the mute level and starts saving the sound signal data. At time t6, the electronic stethoscope 100 determines that the pressing of the diaphragm 206 by the biological surface 300 has ended, based on the displacement signal exceeding threshold Th1, and begins decreasing the volume to the mute level and ends saving the sound signal data. In the example in Figure 14, the sound signal data from time t5 to t6 is saved. Therefore, the saved sound signal data does not include noise that occurred before time t5 and after time t6. Because the volume is low immediately after time t5, the noise immediately after time t5 is reduced. Furthermore, the stored audio signal data does not include extraneous parts that cannot be detected as biological sounds. In this way, high-quality audio signal data is stored in the example shown in Figure 14.

[0097] In the electronic stethoscope 100 described above, a vibration detection unit for detecting vibrations of the diaphragm 206 is configured by a light-emitting element 202 (light source), a light-receiving element 204, and a light-reflecting part 207. The method in Figure 10 may be performed by an electronic stethoscope with a different configuration. For example, the method in Figure 10 may be performed by an electronic stethoscope having a vibration detection unit (e.g., a microphone or piezoelectric element) for detecting air vibrations caused by the vibration of the diaphragm. In this case, the pressure on the diaphragm by the biological surface may be detected using an acceleration sensor or a contact sensor.

[0098] (Other Embodiments) The present invention can also be realized by supplying a program that implements one or more of the functions of the above embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0099] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention.

[0100] This application claims priority based on Japanese Patent Application No. 2024-176741, filed on 8 October 2024, and all of its contents are incorporated herein by reference.

Claims

1. An electronic stethoscope comprising: a diaphragm that contacts a living body and vibrates together with the living body; a vibration detection unit that detects the vibration of the diaphragm; a generation means that generates sound signal data representing a sound generated in the living body based on the signal generated by the vibration detection unit; and a storage means that starts a storage process for saving the sound signal data when the diaphragm is pressed by the living body.

2. The electronic auscultation device according to claim 1, characterized in that the storage process includes transmitting the sound signal data to an external computer that writes the sound signal data to a storage device.

3. The electronic auscultation device according to claim 1 or 2, characterized in that the storage process includes writing the sound signal data to a storage device included in the electronic auscultation device.

4. The electronic auscultation device according to any one of claims 1 to 3, characterized in that the preservation means terminates the preservation process when the diaphragm is no longer pressed by the living body.

5. The electronic auscultation device according to any one of claims 1 to 4, wherein the electronic auscultation device enters a standby state in response to receiving a standby start instruction to wait for the start of the preservation process, and the preservation means starts the preservation process in response to the detection of pressing of the diaphragm by the living body while the electronic auscultation device is in the standby state.

6. The electronic auscultation device according to claim 5, characterized in that it includes an operating unit for obtaining the standby start instruction from the user.

7. The electronic auscultation device according to claim 5 or 6, characterized in that it includes a communication unit for obtaining the standby start instruction from an external computer.

8. The electronic auscultation device according to any one of claims 1 to 7, characterized in that the vibration detection unit includes: a light reflecting portion provided on the surface of the diaphragm opposite to the contact surface that contacts the living body; a light source; and a light receiving element having a light receiving surface that receives light emitted from the light source and specularly reflected by the light reflecting portion, and generating a signal corresponding to the light that reaches the light receiving surface.

9. The electronic auscultation device according to claim 8, further comprising detection means for detecting the pressure on the diaphragm by the living body based on the signal generated by the light-receiving element.

10. The electronic auscultation device according to any one of claims 1 to 9, characterized in that the sound signal data is stored as an audio file in a storage device by the storage process.

11. The electronic auscultation device according to any one of claims 1 to 10, characterized in that the generating means increases the volume of the sound signal data from a mute level in response to the detection of pressing of the diaphragm by the living body.

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