Electronic stethoscope

Abstract

Stores high-quality audio signal data. [Solution] The electronic stethoscope includes a diaphragm that contacts and vibrates with the living body, a vibration detection unit that detects the vibration of the diaphragm, a generation unit that generates sound signal data representing the sound generated by the living body based on the signal generated by the vibration detection unit, a detection unit that detects the pressure of the diaphragm by the living body, and a storage unit that starts a storage process to save the sound signal data in response to the detection of pressure of the diaphragm by the living body. It is equipped with.

Description

Technical Field

[0001] The present invention relates to an electronic stethoscope device.

Background Art

[0002] In recent years, electronic stethoscope devices that have sensors for measuring vibrations of a living body and can acquire body sounds by the sensors have begun to spread. Patent Document 1 proposes operating an application of a terminal device to record auscultation sound data.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[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 device contacts the body surface or data in an extra section where the electronic stethoscope device is not in contact with the body surface is included in the sound signal data. Some aspects of the present invention aim to provide a technique for storing high-quality sound signal data.

Means for Solving the Problems

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

Effects of the Invention

[0006] The above embodiment makes it possible to store high-quality audio signal data. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram illustrating an example of the appearance of an electronic stethoscope in some embodiments. [Figure 2] A schematic diagram illustrating an example of the configuration of a chestpiece in some embodiments. [Figure 3] A schematic diagram illustrating an example of the operation of the chestpiece in some embodiments. [Figure 4] A schematic diagram illustrating an example of the movement of reflected light in some embodiments. [Figure 5] A diagram illustrating the relationship between displacement amount and displacement signal in some embodiments. [Figure 6] A block diagram illustrating an example of the circuit configuration of an electronic stethoscope in some embodiments. [Figure 7] A block diagram illustrating an example of the functional configuration of an electronic stethoscope in some embodiments. [Figure 8] A block diagram illustrating an example of the circuit configuration of a computer in some embodiments. [Figure 9] A schematic diagram illustrating an example of a computer screen in some embodiments. [Figure 10] A flowchart illustrating an example of a storage method for an electronic auscultation device of some embodiments. [Figure 11] A sequence diagram illustrating an example of the interaction between an electronic stethoscope and a computer in some embodiments. [Figure 12] A diagram illustrating an example of audio signal data saved in a comparative example. [Figure 13] A diagram illustrating an example of stored audio signal data in some embodiments. [Figure 14] A diagram illustrating an example of stored audio signal data in some embodiments. [Modes for carrying out the invention]

[0008] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, 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.

[0009] [Appearance of an electronic stethoscope] Referring to Figure 1, the appearance of the electronic stethoscope 100 according to one embodiment will be described. In Figure 1 and some of the 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 stethoscope 100 when viewed from a certain direction. The electronic stethoscope 100 is a medical device used by doctors, nurses, etc., as a diagnostic instrument to listen to internal sounds of the body. The electronic stethoscope 100 is mainly used to listen to heart sounds and respiratory sounds.

[0010] 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.

[0011] The gripping section 120 is used by the user of the electronic stethoscope 100 to grip the diaphragm 206 when bringing it into close contact with a biological surface. The gripping section 120 is rod-shaped, with the chestpiece 110 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. The circuit board has circuit elements mounted on it for controlling the operation of the electronic stethoscope 100. The gripping section 120 further includes a display section 122, an operating section 123, a power switch 124, and a connector 125.

[0012] The display unit 122 has a plurality of indicators, and each indicator displays the state of the electronic stethoscope 100. For example, states such as the power-on state, the current operation mode, the communication state with the computer, and whether the chest piece 110 is pressed against the living body surface are notified by these indicators.

[0013] The operation unit 123 has a plurality of physical buttons for accepting settings of the electronic stethoscope 100, and accepts operations from the user via these buttons. Specifically, the operation 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 operation mode of the electronic stethoscope 100. The electronic stethoscope 100 can operate by switching among a plurality of operation modes including a heart sound mode, a breath sound mode, and a power saving mode. The heart sound mode is an operation mode for listening to heart sounds. The breath sound mode is an operation mode for listening to breath sounds. The power saving mode is an operation mode with less power consumption than the heart sound mode and the breath sound mode. Also, the electronic stethoscope 100 acquires an instruction to start or end recording by a long press operation of the mode switching button 123c.

[0014] The power switch 124 is a switch for switching on and off the power of the electronic stethoscope 100. The connector 125 is a connector for receiving a cable or a connector of an external device. Power is supplied to the battery included in the grip portion 120 from an external device through the connector 125.

[0015] [Cross-sectional Configuration of Chest Piece of Electronic Stethoscope] Referring to FIG. 2, a configuration example of the chest piece 110 will be described. The upper side of FIG. 2 shows a cross-sectional view of the chest piece 110, and the lower side of FIG. 2 shows a plan view of the chest piece 110. In the plan view, only the light emitting circuit board 203, the light receiving circuit board 205, the diaphragm 206, and the light reflecting portion 207 are shown to clarify the positional relationship of the components.

[0016] 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 thereon, the housing 208 also houses the diaphragm portions 209 and 210 thereon. The diaphragm 206, together with the housing 208, forms part of the exterior of the electronic stethoscope 100.

[0017] The light-emitting element 202 is a light-emitting diode (LED). Power is supplied to the light-emitting element 202 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.

[0018] 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 comes 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.

[0019] 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.

[0020] 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 a 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, which 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.

[0021] 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.

[0022] 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 in which the opening is formed corresponds to the diaphragm portion 209.

[0023] 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, allowing 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.

[0024] A housing 208 is attached to the upper outer surface of the retaining 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.

[0025] [Example of electronic stethoscope operation] Referring to Figure 3, an example of the operation of the chestpiece 110 of the electronic stethoscope 100 will be described. As shown in Figure 3, 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 respiration of the person having the biological surface 300.

[0026] Figure 3(a) 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 such 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.

[0027] Figure 3(b) 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. Consequently, 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 3(b), since the reflected light 212 does not reach the photodetector 204 at all, the value of the displacement signal is ideally zero.

[0028] 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.

[0029] [Relationship between diaphragm displacement and the displacement of the reflected light receiving position in an electronic stethoscope] Referring to Figure 4, the relationship between the displacement of the biological surface 300, the incident angle of the incident light 211, the incident angle of the 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 is considered the reference position when the diaphragm 206 is flat. Position 402 indicates the position where the upper surface of the light-reflecting part 207 is displaced upward by a displacement of d2 from position 401. Since the displacement d2 of the light-reflecting part 207 is small, the upper surface of the light-reflecting part 207 is considered flat even when it is at position 402.

[0030] In Figure 4, 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 element 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 element 207. When the upper surface of the light-reflecting element 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 element 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 element 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 of the position where the light-receiving element 204 receives the reflected light 212 is denoted as d3. The displacement d3 may also be defined by the displacement 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 d3 to the displacement d2 is denoted as the displacement ratio G. In this case, G=2×sinθ / cosφ…(Formula 1) The following relationship holds true. Therefore, even if the displacement d2 of the light reflecting part 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.

[0031] 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 is: G=2×sinθ…(Formula 2) Therefore, the larger the angle of incidence θ, the larger the displacement d3 becomes.

[0032] 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.

[0033] [Relationship between displacement amount and displacement signal on the biological surface of an electronic stethoscope] Referring to Figure 5, the relationship between the displacement of the biological surface 300 and the displacement signal will be explained. 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 of the biological surface 300 and the displacement signal. The horizontal axis of graph 500 represents the displacement of the biological surface 300 and the displacement signal generated by the light-receiving circuit board 205.

[0034] 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 Figure 3, 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, Sd=Vmax-k×d3…(Formula 6) This is the result. Here, Vmax is the value of the displacement signal when the displacement amount 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 light receiving circuit board 205. By substituting equation 1 into equation 6, Sd=Vmax-2k×d2×sinθ / cosφ…(Formula 7) This is obtained. Therefore, the displacement signal Sd decreases monotonically and linearly as the displacement amount d2 of the biological surface 300 increases, as shown in graph 500. 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.

[0035] 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.

[0036] 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.

[0037] [Example of circuit configuration for an electronic stethoscope] Referring to Figure 6, an example of the circuit configuration of the electronic stethoscope 100 will be described. The microcontroller 600 is a control means that controls the overall operation of the electronic stethoscope 100. In Figure 6, the electronic stethoscope 100 includes one microcontroller 600. Alternatively, the electronic stethoscope 100 may include multiple microcontrollers 600. The microcontroller 600 includes a processor 601, a non-volatile memory 602, a Bluetooth® circuit 603, and RAM 604. The processor 601 controls the operation of the electronic stethoscope 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 stethoscope 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 compliant with 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.

[0038] 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 photodetector 204 to an external audio output device 670 via the wireless communication unit 618 or the 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.

[0039] The displacement signal output from the photodetector 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 communication standard, to be 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.

[0040] Although the electronic stethoscope 100 described above is 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. Transmission of sound signal data to the computer 680 is similar to transmission of 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 (e.g., the sound output device 670 or the computer 680).

[0041] 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 computer 680). The UART integrated circuit 620 may be able to operate with the voltage VBUS as its operating voltage.

[0042] 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.

[0043] Battery 611 stores electrical energy used by the electronic stethoscope 100. Battery 611 may have a function to cut off the current flowing through it if it exceeds a threshold. The charging integrated circuit 612 is an integrated circuit (IC) that controls the charging of battery 611 and the discharging of battery 611. For example, the charging integrated circuit 612 charges battery 611 using electrical energy supplied from an external device such as a charger or computer 680 connected to connector 125. The charging integrated circuit 612 also supplies the electrical energy stored in battery 611 to the boost converter 613. The voltage provided by the charging integrated circuit 612 is denoted as voltage VBAT. Voltage VBAT is, for example, 3.7V.

[0044] The boost converter 613 boosts a DC voltage to another DC voltage of a different value. The boost converter 613 is also called a DC / DC converter. The boost converter 613 boosts the voltage VBAT supplied from the charging integrated circuit 612 to voltage V0. 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, also called a low-dropout regulator (LDO). The voltage regulator 614 generates the operating voltage for some circuit elements of the electronic stethoscope 100. The voltage generated by the voltage regulator 614 is denoted as voltage V1. The voltage regulator 614 may also generate the operating voltage for the microcontroller 600, for example, voltage V1 is 3.3V. The operating voltage of the accelerometer 650 is also voltage V1. In the example in Figure 6, voltage V1 is applied to the microcontroller 600 and the accelerometer 650, respectively. The microcontroller 600 and the accelerometer 650 are powered by the voltage regulator 614 of the power supply unit 610. The voltage regulator 614 outputs voltage V1 when a voltage higher than voltage V1 is applied to its input terminal. Therefore, the voltage regulator 614 outputs voltage V1 when voltage V0 is supplied from the boost converter 613.

[0045] 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 also 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.

[0046] The displacement signal processing unit 630 processes the diaphragm displacement signal to generate an audio signal representing the sound transmitted from the biological surface to the diaphragm 206, and outputs this audio signal to the microcontroller 600. Specifically, the displacement signal processing unit 630 extracts components of a specific frequency band included in the diaphragm displacement signal to generate an audio signal. As will be described later, the extracted components of a specific frequency band include components in the frequency band range from 10 Hz to 1 kHz. The diaphragm displacement signal is a signal generated and output by the photodetector 204 in accordance with the amount of light that reaches the photodetector 204. Hereinafter, the diaphragm displacement signal will simply be referred to as the displacement signal. The amount of light that reaches the photodetector 204 changes in accordance with the displacement of the diaphragm 206. Note that, as described above, if the light-emitting element 202 is a laser diode that emits laser light, the displacement signal may also refer to a signal generated and output by the photodetector 204 in accordance with the position of the light that reaches the photodetector 204. Even when implemented with a laser diode, the displacement signal still represents the displacement of the diaphragm 206. The heartbeat sound signal is also a type of displacement signal because it represents the displacement of the diaphragm 206 (specifically, its components in a particular frequency band).

[0047] 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 photodetector 204 and the microcontroller 600. These circuit elements are connected in series. The displacement signal processing unit 630 receives a displacement signal from the photodetector 204 and outputs an audio signal to the microcontroller 600.

[0048] The buffer circuit 631 receives a displacement signal from the photodetector 204 and outputs that displacement signal to the HPF 632. The buffer circuit 631 performs impedance conversion of the signal path between the photodetector 204 and the HPF 632. For example, the output impedance of the buffer circuit 631 is lower than the output impedance of the photodetector 204. The operating power of the buffer circuit 631 is supplied by the voltage regulator 616.

[0049] HPF632 outputs a signal to amplifier circuit 633 obtained by attenuating the low-frequency components (i.e., frequency components lower than a specific cutoff frequency) of the displacement signal received from buffer circuit 631 and passing the high-frequency components (i.e., frequency components higher than the said cutoff frequency) of the displacement signal. HPF632 attenuates components below 10Hz from the displacement signal received from buffer circuit 631, so the cutoff frequency of HPF632 is set to, for example, 10Hz. However, the cutoff frequency may be a value greater than 10Hz, for example, 15Hz or 20Hz. Also, the cutoff frequency may be 10Hz or more and less than 20Hz. Therefore, HPF632 removes or attenuates components below 10Hz from the displacement signal received from buffer circuit 631.

[0050] 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.

[0051] [Example of an electronic stethoscope's functional configuration] 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).

[0052] 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.

[0053] 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.

[0054] The pressure detection unit 705 detects that the diaphragm 206 is being pressed or in contact with something based on the displacement signal obtained 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 identifies 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. 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 the not-use state when the amount of displacement of the diaphragm 206 identified from the displacement signal is less than a threshold. On the other hand, the pressure detection unit 705 determines that the pressure state is in use when the amount of displacement of the diaphragm 206 exceeds the threshold.

[0055] 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 heart 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 heart 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 heart sound mode is referred to as the heart 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.

[0056] 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.

[0057] 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.

[0058] 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., 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.

[0059] 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 played back 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.

[0060] 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 by the output control unit 706.

[0061] [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 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.

[0062] 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).

[0063] 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.

[0064] The communication device 805 is a device for communicating with an external device (e.g., the electronic stethoscope 100) of the computer 680. When the computer 680 uses wired communication, the communication device 805 is a network interface card (NIC) with 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.

[0065] 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.

[0066] 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.

[0067] [Screen provided by the linked application] Referring to Figure 9, an example of a screen 900 provided by the linked application 807 will be described. Screen 900 is displayed on the display device 804. Screen 900 includes a setting area 910 on which objects related to the settings of the electronic stethoscope 100 are placed, and a display area 920 on which objects related to the display of sound signal data received from the electronic stethoscope 100 are placed.

[0068] The settings area 910 includes objects 911-913, a pairing button 914, and a settings 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.

[0069] 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.

[0070] 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. When the pairing button 914 is pressed by the user, the linked application 807 starts pairing with the electronic stethoscope 100. 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. When the setting update button 915 is pressed by the user, the linked application 807 sends the settings specified in objects 911 to 913 to the electronic stethoscope 100. 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 this case, the linked application 807 sends new settings to the electronic stethoscope 100 each time the settings in objects 911 to 913 are changed.

[0071] 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 in 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.

[0072] [Audio signal data saving process] Referring to Figure 10, a method for performing the storage process of sound signal data will be described. 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 (e.g., heart sound mode or respiratory sound mode) and end the method in Figure 10 when the electronic stethoscope 100 transitions to power-saving mode.

[0073] 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.

[0074] The processor 601 considers a user pressing and holding (for example, for 1 second or more) the mode switching button 123c on the control unit 123 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 may include 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.

[0075] 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 the biological surface 300 pressing the diaphragm 206. If the processor 601 determines that the biological surface 300 has started pressing the diaphragm 206 (YES in S1002), it proceeds to S1003; otherwise (NO in S1002), it repeats S1002. In this way, the processor 601 waits for the biological surface 300 to start pressing the diaphragm 206.

[0076] In S1003, when the diaphragm 206 is pressed 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 the data. Saving the data is the process of saving the sound signal data. When the electronic stethoscope 100 is set as the save destination, the saving process 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 the sound signal data to this file. The processor 601 appends the new portion of the sound signal data to the file each time a new portion is generated.

[0077] 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 the electronic stethoscope 100 to the file.

[0078] If the volume of the sound signal data is set to fade in, the processor 601 (e.g., 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 (e.g., 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.

[0079] 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.

[0080] 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, in response to the electronic stethoscope 100 no longer transmitting sound signal data, finishes writing the sound signal data to the file in memory 802 and closes the file. 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.

[0081] 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 the medical information server.

[0082] [Table 1]

[0083] 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.

[0084] 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.

[0085] 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.

[0086] [Integration between electronic stethoscopes and computers] Referring to Figure 11, an example of the operation in which the electronic stethoscope 100 and the computer 680 work together will be described. 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 configures 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 collaborative 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.

[0087] In S1101, the computer 680 displays 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 911-913 on screen 900 are selected, and no data is displayed in 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.

[0088] In S1104, 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 the computer 680 with its current settings. Computer 680 reflects the settings provided by the electronic stethoscope 100 in objects 911-913 on screen 900. In the following, it is assumed that computer 680 is specified as the storage location for the sound signal data.

[0089] 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 sends 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.

[0090] 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.

[0091] 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 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.

[0092] [Example of audio signal data to be saved] Refer to Figures 12 to 14 to illustrate an example of the audio signal data that is saved. Figure 12 illustrates a comparative example in which the saving of audio 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 to instruct the start of saving audio signal data, and the audio signal data saving process begins. At this time, noise caused by the button operation is generated in the audio 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 audio signal data. Subsequently, heart sounds are measured.

[0093] 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 button operation. 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 parts of the period 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.

[0094] 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 the 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 the 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 where biological sounds cannot be detected. Thus, in the example in Figure 13, high-quality sound signal data is saved.

[0095] 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 the 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 the 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 or 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.

[0096] 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 element 207. The method shown in Figure 10 may be performed by an electronic stethoscope with a different configuration. For example, the method shown 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.

[0097] [Summary of Embodiments] (Item 1) A diaphragm that comes into contact with a living organism and vibrates together with the living organism, A vibration detection unit for detecting vibrations of the diaphragm, A generation means for generating sound signal data representing sound generated in the living body based on the signal generated by the vibration detection unit, A detection means for detecting the pressure on the diaphragm by the biological body, A storage means that, upon detection of the pressing of the diaphragm by the living body, initiates a storage process for saving the sound signal data, An electronic stethoscope characterized by being equipped with the following features. (Item 2) The electronic auscultation device according to item 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. (Item 3) The electronic auscultation device according to item 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. (Item 4) The electronic auscultation device according to any one of items 1 to 3, characterized in that the preservation means terminates the preservation process in response to the fact that pressure on the diaphragm by the living body is no longer detected. (Item 5) The electronic auscultation device enters a standby state in response to receiving a standby start instruction to wait for the start of the storage process. The electronic auscultation device according to any one of items 1 to 4, characterized in that the storage means starts the storage process in response to the detection of pressing of the diaphragm by a living body while the electronic auscultation device is in the standby state. (Item 6) The electronic auscultation device according to item 5, characterized in that it includes an operating unit for obtaining the standby start instruction from the user. (Item 7) The electronic auscultation device according to item 5 or 6, characterized in that it includes a communication unit for obtaining the standby start instruction from an external computer. (Item 8) The vibration detection unit is A light-reflecting portion is provided on the side of the diaphragm opposite to the contact surface that comes into contact with the living body, Light source and An electronic auscultation device according to any one of items 1 to 7, characterized by having a light-receiving surface that receives light emitted from the light source and specularly reflected by the light-reflecting part, and a light-receiving element that generates a signal corresponding to the light that reaches the light-receiving surface. (Item 9) The electronic auscultation device according to item 8, characterized in that the detection means detects the pressure on the diaphragm by the living body based on the signal generated by the light-receiving element. (Item 10) The electronic auscultation device according to any one of items 1 to 9, characterized in that the sound signal data is saved as an audio file by the saving process. (Item 11) The electronic auscultation device according to any one of items 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.

[0098] 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. [Explanation of symbols]

[0099] 100 Electronic stethoscope, 202 Light-emitting element, 204 Photodetector, 206 Diaphragm, 680 Computer

Claims

1. A diaphragm that comes into contact with a living organism and vibrates together with the living organism, A vibration detection unit for detecting vibrations of the diaphragm, A generation means for generating sound signal data representing sound generated in the living body based on the signal generated by the vibration detection unit, A detection means for detecting the pressure on the diaphragm by the biological body, A storage means that, upon detection of the pressing of the diaphragm by the living body, initiates a storage process for saving the sound signal data, An electronic stethoscope characterized by being equipped with the following features.

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, 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 claim 1, characterized in that the preservation means terminates the preservation process when the pressing of the diaphragm by the living body is no longer detected.

5. The electronic auscultation device enters a standby state in response to receiving a standby start instruction to wait for the start of the storage process. The electronic auscultation device according to claim 1, characterized in that the storage means starts the storage process in response to the detection of pressing of the diaphragm by a 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, characterized in that it includes a communication unit for obtaining the standby start instruction from an external computer.

8. The vibration detection unit is A light-reflecting portion is provided on the side of the diaphragm opposite to the contact surface that comes into contact with the living body, Light source and The electronic auscultation device according to claim 1, characterized in that it has a light-receiving surface that receives light emitted from the light source and specularly reflected by the light-reflecting part, and a light-receiving element that generates a signal corresponding to the light that reaches the light-receiving surface.

9. The electronic auscultation device according to claim 8, characterized in that the detection means detects 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 claim 1, characterized in that the sound signal data is saved as an audio file by the saving process.

11. The electronic auscultation device according to claim 1, 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.

Images