Electronic device

Abstract

This electronic device has: a diaphragm that comes into contact with an object being measured, the diaphragm being provided with a light reflection part on a surface on the side opposite from the contact surface of the diaphragm that comes into contact with the object being measured; a light-emitting diode; a throttling part for throttling light emitted from the light-emitting diode; a light-receiving element having a light-receiving surface for receiving light that passes through the throttling part and is regularly reflected by the light reflection part; an output unit for outputting a signal corresponding to light in a light irradiation region formed by the regularly reflected light reaching the light-receiving surface; and a housing for accommodating the light-emitting diode, the throttling part, and the light-receiving element therein. The diaphragm is configured so as to form, together with the housing, a portion of the exterior of the electronic device, and to elastically deform upon being pressed by the object being measured in contact with the contact surface. A boundary line between the light irradiation region and a region other than the light irradiation region on the light-receiving surface, the boundary line being formed by the light that has been throttled by the throttling part and regularly reflected by the light reflection part, moves in accordance with displacement of the contact surface caused by the elastic deformation of the diaphragm, whereby the area of the light irradiation region on the light-receiving surface changes and the output of the output unit changes.

Description

electronic equipment

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

[0002] In recent years, electronic devices such as electronic auscultation devices that have sensors for measuring vibrations of living bodies and can acquire body sounds using the sensors have become widespread. Patent Document 1 proposes an electronic auscultation device that acquires body sounds using a capacitive microphone. Patent Document 2 proposes an auscultation device that uses a vibration sensor in an acquisition unit for acquiring body sounds.

[0003] JP 2022-119446 A JP 2017-47095 A

[0004] With a microphone sized to fit into an auscultation device such as that disclosed in Patent Document 1, it is difficult to accurately detect low-frequency band vibrations around 10 Hz emitted by a living body. With an auscultation device that uses a vibration sensor to detect living body vibrations, such as that disclosed in Patent Document 2, a certain amount of pressure is applied because the vibration sensor is pressed against the surface of the living body, reducing the amount of displacement of the surface of the living body and worsening the S / N ratio. With conventional electronic devices, it has been difficult to accurately measure the vibrations of a measurement target such as a living body. Some aspects of the present invention provide a technique for accurately measuring the vibrations of a measurement target.

[0005] According to some embodiments, an electronic device includes: a diaphragm that contacts an object to be measured, the diaphragm having a light reflecting portion on a surface of the diaphragm opposite to a contact surface that contacts the object to be measured; a light emitting diode; an aperture portion that narrows down the light emitted from the light emitting diode; a light receiving element having a light receiving surface that receives light that has passed through the aperture portion and is specularly reflected by the light reflecting portion; output means that outputs a signal corresponding to light in a light irradiation area formed by the specularly reflected light that has reached the light receiving surface; and a housing that houses the light emitting diode, the aperture portion, and the light receiving element. The diaphragm, together with the housing, forms part of the exterior of the electronic device, and is configured to elastically deform when pressed by the object to be measured that contacts the contact surface, and the boundary line between the light-irradiated area on the light-receiving surface and the area other than the light-irradiated area, which is formed by light that has been narrowed by the aperture section and specularly reflected by the light-reflecting section, moves in accordance with the displacement of the contact surface due to the elastic deformation of the diaphragm, thereby changing the area of ​​the light-irradiated area on the light-receiving surface and changing the output of the output means.

[0006] According to the above embodiment, the displacement of the object to be measured can be measured with high accuracy.

[0007] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0008] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments of the present invention, and are used, together with the description, to explain the principles of the present invention.

[0023] Figure 1 is a schematic diagram illustrating an example of the appearance of an electronic auscultation device according to a first embodiment.

[0024] Figure 2 is a schematic diagram illustrating an example of the appearance of an electronic auscultation device according to a first embodiment.

[0025] Figure 3 is a schematic diagram illustrating an example of the configuration of a chestpiece according to a first embodiment.

[0026] Figure 4 is a schematic diagram illustrating a modified version of the chestpiece according to a first embodiment.

[0027] Figure 5 is a schematic diagram illustrating a modified version of the chestpiece according to a first embodiment.

[0028] Figure 6 is a schematic diagram illustrating an example of the operation of the chestpiece according to a first embodiment.

[0029] Figure 7 is a schematic diagram illustrating an example of the movement of reflected light according to a first embodiment.

[0030] Figure 8 is a schematic diagram illustrating an example of the movement of reflected light according to a first embodiment.

[0031] Figure 9 is a schematic diagram illustrating an example of the movement of reflected light according to a first embodiment.

[0032] Figure 10 is a block diagram illustrating an example of the configuration of an electronic auscultation device according to a first embodiment.

[0033] Figure 11 is a schematic diagram illustrating an example of the operation of the chestpiece according to a first embodiment. Schematic diagrams illustrating an example of operation of the chestpiece of the first embodiment. Schematic diagrams illustrating an example of operation of the chestpiece of the first embodiment. Schematic diagrams illustrating an example of operation of the chestpiece of the first embodiment. Schematic diagrams illustrating an example of change in the light receiving range of the first embodiment. Schematic diagrams illustrating a first modified example of the chestpiece of the first embodiment. Schematic diagrams illustrating a first modified example of the chestpiece of the first embodiment. Schematic diagrams illustrating a second modified example of the chestpiece of the first embodiment. Schematic diagrams illustrating a second modified example of the chestpiece of the first embodiment. A diagram illustrating the relationship between the displacement amount and the displacement signal of the second modified example. Schematic diagrams illustrating a third modified example of the chestpiece of the first embodiment. Schematic diagrams illustrating a third modified example of the chestpiece of the first embodiment. A diagram summarizing the configurations of the first embodiment and each modified example. Block diagram illustrating an example of the configuration of an electronic auscultation device of the second embodiment. Schematic diagrams illustrating an example of the configuration of a chestpiece of the second embodiment. Schematic diagrams illustrating an example of the configuration of a chestpiece of the second embodiment. 10A and 10B are schematic diagrams illustrating an example of the configuration of a chest piece according to a second embodiment.Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining an example configuration of a chest piece according to a second embodiment. Schematic diagram for explaining a modified version of the chest piece according to the second embodiment. Schematic diagram for explaining a modified version of the chest piece according to the second embodiment. Schematic diagram for explaining a modified version of the chest piece according to the second embodiment. Schematic diagram for explaining a modified example of the chestpiece of the second embodiment. Schematic diagram for explaining a modified example of the chestpiece of the second embodiment. Schematic diagram for explaining a modified example of the chestpiece of the second embodiment. Block diagram for explaining an example of the circuit configuration of the electronic auscultation device of the second embodiment. Diagram for explaining the effect of the ... Block diagram for explaining an example of the functional configuration of the electronic auscultation device of the second embodiment. Flow diagram for explaining an example of the operation of the electronic auscultation device of the second embodiment. Flow diagram for explaining an example of the operation of the electronic auscultation device of the second embodiment. Schematic diagram for explaining an example of the operation of the electronic auscultation device of the second embodiment. Flow diagram for explaining an example of the operation of the electronic auscultation device of the second embodiment. 5A and 5B are schematic diagrams illustrating an example of the operation of the electronic auscultation device according to the second embodiment.Schematic diagram for explaining a display example of the electronic auscultation device of the second embodiment. Schematic diagram for explaining a modified ... state transition example of the electronic auscultation device of the second embodiment. Flow diagram for explaining an example of state transition of the electronic auscultation device of the second embodiment. Flow diagram for explaining an example of state transition of the electronic auscultation device of the second embodiment. Schematic diagram for explaining an operation example of the electronic auscultation device of the second embodiment. Schematic diagram for explaining an operation example of the electronic auscultation device of the second embodiment. Schematic diagram for explaining an example configuration of the electronic auscultation device of the third embodiment. Schematic diagram for explaining an example configuration of the electronic auscultation device of the third embodiment. Schematic diagram for explaining an example configuration of the electronic auscultation device of the third embodiment. Schematic diagram for explaining an example configuration of the electronic auscultation device of the third embodiment. Schematic diagram for explaining a configuration example of an electronic auscultation device of a third embodiment. Schematic diagram for explaining a configuration example of an electronic auscultation device of a third embodiment. Schematic diagram for explaining a configuration example of an electronic auscultation device of a third embodiment. Schematic diagram for explaining a configuration example of an electronic auscultation device of a third embodiment. Schematic diagram for explaining a modified example of the electronic auscultation device of a third embodiment. Schematic diagram for explaining a modified example of the electronic auscultation device of a third embodiment. Schematic diagram for explaining a modified example of the electronic auscultation device of a fourth embodiment. Schematic diagram for explaining a configuration example of an ... A schematic diagram for explaining a modified example of the electronic auscultation device of the fourth embodiment. A schematic diagram for explaining a modified example of the electronic auscultation device of the fourth embodiment. A schematic diagram for explaining a modified example of the electronic auscultation device of the fourth embodiment. A schematic diagram for explaining a modified example of the electronic auscultation device of the fourth embodiment.Schematic diagram for explaining a modified example of the electronic auscultation device of the fourth embodiment. ...

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

[0010] First Embodiment [Appearance of the Electronic Auscultation Device in the First Embodiment] The appearance of the electronic auscultation device 100 according to the first embodiment will be described with reference to FIGS. 1A to 9B . Note that the following drawings may be accompanied by a coordinate system CS, which is a three-dimensional Cartesian coordinate system having an x-axis, a y-axis, and a z-axis, to explain the directions. In these descriptions, the positive direction of the z-axis may be referred to as the upper side, and the negative direction of the z-axis may be referred to as the lower side. FIG. 1A shows the appearance of the electronic auscultation device 100 when viewed from one direction, and FIG. 1B shows the appearance of the electronic auscultation device 100 when viewed from another direction. The electronic auscultation device 100 is an electronic device used as a diagnostic tool for listening to internal sounds of living organisms such as humans or animals. The electronic auscultation device 100 is primarily used to listen to heartbeats and respiratory sounds.

[0011] As shown in FIG. 1A, the electronic auscultation device 100 includes a chestpiece 110 and a grip 120. The chestpiece 110 is a unit that is brought into contact with the surface of a living body, which is an example of a subject to be measured, during a diagnosis using the electronic auscultation device 100, to measure minute vibrations (displacements) on the surface of the living body and capture biological sounds. The chestpiece 110 detects minute displacements on the surface of the living body in close contact with the chestpiece 110 via a diaphragm 206 (described below). Therefore, the chestpiece 110 can also be referred to as a displacement detection device or a diaphragm displacement detection device. Furthermore, because the chestpiece 110 is used to detect vibrations on the surface of the living body, it can also be referred to as a biological vibration detection device.

[0012] The gripping portion 120 is gripped by a user (e.g., a doctor, nurse, or public health nurse) of the electronic auscultation device 100 when bringing the diaphragm 206 into close contact with the surface of a living body. Hereinafter, the user of the electronic auscultation device 100 will be simply referred to as the "user." As shown in FIGS. 1A and 1B , the gripping portion 120 is rod-shaped, with the chestpiece 110 attached to one end (the negative x-axis direction in FIGS. 1A and 1B ). The gripping portion 120 is also called a handle, a grip, a handle, or the like. In this embodiment, the gripping portion 120 and the chestpiece 110 are configured to be pivotable relative to each other, but the present invention is not limited to this. The gripping portion 120 may be fixed to the gripping portion 120, or the chestpiece 110 may also function as the gripping portion.

[0013] The grip part 120 has a housing 121. The grip part 120 houses a battery and a circuit board inside the housing 121. The battery stores operating power for the electronic auscultation device 100. The circuit board has circuit elements for controlling the operation of the electronic auscultation device 100. The grip part 120 has a display unit 122, an operation unit 123, a power switch 124, and a connector 125 on the outer surface of the housing 121.

[0014] The display unit 122 displays the status of the electronic auscultation device 100. For example, the display unit 122 may include multiple indicators (four indicators in the example of FIG. 1A ). Each indicator is configured with a light-emitting diode (LED). The multiple indicators include an indicator indicating whether the power of the electronic auscultation device 100 is on or off. The multiple indicators also include an indicator indicating the current operating mode of the electronic auscultation device 100. The multiple indicators also include an indicator indicating whether the electronic auscultation device 100 is wirelessly connected to an external device. The multiple indicators also include an indicator indicating whether the chestpiece 110 is pressed against a living body surface. As shown in FIG. 1A , the display unit 122 is located on the outer surface of the housing 121, on the side opposite the chestpiece 110, near one end in the x-axis direction of the chestpiece 110. In this embodiment, "near the chestpiece 110" means closer to the chestpiece 110 than the center of the grip portion 120. With this arrangement, when a user grips the other end of the grip portion 120 in the x-axis direction, the display portion 122 located at one end in the x-axis direction will not be hidden by the user's hand. As a result, the user can easily see the display portion 122. Note that the display portion 122 does not need to include all of the indicators described above, and instead of or in addition to multiple indicators, a liquid crystal panel or an electrostatic panel may be used to display the status of the electronic stethoscope device 100.

[0015] The operation unit 123 accepts operations from the user. In this embodiment, the operation unit 123 includes multiple physical buttons (three buttons in the example of FIG. 1A) for accepting settings for the electronic auscultation device 100. Specifically, the operation unit 123 includes volume adjustment buttons (volume up button 123a and volume down button 123b) for adjusting the volume of the output sound. When the volume adjustment button is pressed, the electronic auscultation device 100 adjusts the gain of the signal output from the light receiving element 204 and adjusts the volume of the sound output through the earphones. The operation unit 123 also includes a mode switching button 123c for switching the operating mode of the electronic auscultation device 100. When the mode switching button 123c is pressed, the operating mode is switched as described below. In other words, the mode switching button 123c accepts instructions from the user regarding the mode transition of the electronic auscultation device 100. Note that the operation unit 123 may include a touch panel instead of multiple physical buttons. The display unit 122 and the operation unit 123 may be integrated into a touch screen.

[0016] Like the display unit 122, the operation unit 123 is arranged on the outer surface of the housing 121 opposite the chestpiece 110, near one end of the chestpiece 110 in the x-axis direction. This arrangement allows the user to operate the operation unit 123 (for example, with their thumb) while holding the grip unit 120 during use of the electronic auscultation device 100. Furthermore, the display unit 122 is arranged at a position farther away from the center of the grip unit 120 in the x-axis direction than the operation unit 123. This arrangement allows the user to maintain visibility of the display unit 122 even when operating the operation unit 123 during use of the electronic auscultation device 100.

[0017] The power switch 124 is a switch that switches the power of the electronic auscultation device 100 on and off. The connector 125 is a connector for receiving a cable or a connector of an external device. Power is supplied from the external device to the battery included in the grip portion 120 through the connector 125. The power switch 124 may be provided on the chestpiece 110 instead of the grip portion 120. The connector 125 may be provided on the chestpiece 110 instead of the grip portion 120. Furthermore, the electronic auscultation device 100 may not include the connector 125. In this case, the electronic auscultation device 100 may have a wireless charging function or may be configured to have a replaceable battery.

[0018] The electronic auscultation device 100 in this embodiment includes both the chestpiece 110 and the grip portion 120, but may alternatively include only the chestpiece 110 and not the grip portion 120.

[0019] [Chestpiece Configuration of the Electronic Auscultation Device in the First Embodiment] An example configuration of the chestpiece 110 will be described with reference to Fig. 2A. The upper side of Fig. 2A shows a cross-sectional view of the chestpiece 110, and the lower side of Fig. 2A shows a plan view of the chestpiece 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.

[0020] 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 portion 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 portion 207. Because the holding member 201 has apertures 209 and 210, the housing 208 also houses the apertures 209 and 210. The diaphragm 206, together with the housing 208, form part of the exterior of the electronic auscultation device 100. Note that the components of the chestpiece 110 described here are merely examples, and in addition to the components shown in FIG. 2A , the chestpiece 110 may include a circuit board on which circuit elements for controlling its operation are mounted.

[0021] The light-emitting element 202 is a light source that emits light. Power is supplied to the light-emitting element 202 from a power source external to the chestpiece 110 (a battery in the grip portion 120). In this embodiment, the light-emitting element 202 is a light-emitting diode (LED).

[0022] The light-emitting element 202 is mounted on a light-emitting circuit board 203. On the light-emitting circuit board 203, for example, a peripheral circuit for regulating the light emission amount of the light-emitting element 202 and a power supply terminal for receiving power from a power source external to the chest piece 110 are mounted. The light-emitting circuit board 203 may be a printed wiring board such as a flexible circuit board, or may be a paper phenolic board or a glass epoxy board. The light-emitting circuit board 203 including the light-emitting element 202 functions as a light-emitting unit.

[0023] The light receiving element 204 generates an electrical signal based on the amount of light received using power supplied from a power source external to the chestpiece 110 (e.g., a battery in the grip portion 120). The power supplied to the light receiving element 204 is supplied from a power source external to the chestpiece 110 (e.g., a battery in the grip portion 120). The light receiving element 204 may be, for example, a phototransistor or a complementary metal-oxide semiconductor (CMOS) sensor. In this embodiment, the number of light receiving elements 204 is one, but the present invention is not limited to this. A line sensor (light receiving elements arranged in a 1×n (n≧2)) or an area sensor (light receiving elements arranged in an m×n (m≧2, n≧2)) may be formed using a plurality of light receiving elements 204.

[0024] 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 mounted with peripheral circuits for reading out signals from the light receiving element 204, a signal terminal for outputting signals to a device external to the chest piece 110, and a power supply terminal for receiving power from a power source external to the chest piece 110. The light receiving circuit board 205 may be a printed wiring board such as a flexible circuit board, or may be a paper phenolic board or a glass epoxy board. The light receiving circuit board 205 including the light receiving element 204 functions as a light receiving unit.

[0025] The holding member 201 holds the light-emitting circuit board 203 and the light-receiving circuit board 205. The light-emitting circuit board 203 and the light-receiving circuit board 205 are fixed to the holding member 201. These boards may be fixed to the holding member 201 using an adhesive or using fastening members such as screws.

[0026] The diaphragm 206 has a contact surface 206a that contacts the surface of a living body, which is an example of a subject to be measured, and an inner surface 206b that is the surface opposite the contact surface 206a. The diaphragm 206 is configured to elastically deform when pressed by the subject to be measured contacting the contact surface 206a. The inner surface 206b of the diaphragm 206 is provided with a light reflecting portion 207, which will be described later. In this embodiment, the diaphragm 206 is a laminated plate of glass epoxy resin, which is formed by impregnating glass fiber with epoxy resin and then subjecting it to a heat curing treatment. The thickness is 230 μm. The diaphragm 206 also has an integrated ring-shaped rim for securing the diaphragm 206 to the holding member 201 or the housing 208. In this embodiment, the contact surface 206a and inner surface 206b of the diaphragm 206 refer to the portions of the diaphragm 206 that do not include the ring-shaped rim integrated with the diaphragm 206. The diaphragm 206 may have a multi-layer structure. In this case, the outermost layer of the multi-layered diaphragm 206 that contacts the object to be measured is defined as the contact surface 206a, and the innermost layer on which the light reflecting portion 207 is provided is defined as the inner surface 206b. The diaphragm 206 may be composed of multiple layers or members as long as it vibrates integrally with the object to be measured when it comes into contact with it. In this embodiment, even if a separate cover is attached to the contact surface 206, this configuration is considered to be one form of the diaphragm 206 as long as the cover and the contact surface 206a vibrate integrally with the object to be measured. Furthermore, the contact surface 206a of the diaphragm 206 is exposed to the outside when the electronic auscultation device 100 is in use, but may be covered with a protective cover when not in use to prevent damage or deterioration to the contact surface 206a.

[0027] The diaphragm 206 is held by the holding member 201. The diaphragm 206 extends along the xy plane of the coordinate system CS. The diaphragm 206 is arranged so as to contact the surface of a living body, which is an example of a measurement target. The diaphragm 206 forms part of the exterior of the chestpiece 110. The diaphragm 206 has a contact surface 206a arranged so as to contact the surface of a living body when the electronic auscultation device 100 is in use, and an inner surface 206b opposite the contact surface 206a.

[0028] The diaphragm 206 has a fixed portion 206c and is fixed to the holding member 201. The fixed portion 206c is located on the outer periphery of the diaphragm 206. The inner periphery of the diaphragm 206 (i.e., the portion inside the fixed portion 206c) is not fixed to the holding member 201. Therefore, the diaphragm 206 can vibrate in the z-axis direction with the fixed portion 206c as a node. Specifically, when the chestpiece 110 is in use, the diaphragm 206 vibrates with the fixed portion 206c as a node in response to displacement of the surface of the living body. In this vibration, the center 206e of the diaphragm 206 becomes an antinode. The diaphragm 206 functions as a vibrating part that vibrates together with the object to be measured.

[0029] The light reflecting portion 207 reflects light emitted from the light emitting element 202. The light reflecting portion 207 is adhered to the inner surface 206b of the diaphragm 206 and moves integrally with the diaphragm 206 in the z-axis direction in response to vibration of the diaphragm 206, which is in close contact with the surface of the living body. The light reflecting portion 207 has a circular outer edge in a plan view. The light reflecting portion 207 may have a diameter of 15 mm to 20 mm. Alternatively, the outer edge of the light reflecting portion 207 may have another shape. The light reflecting portion 207 is positioned to cover an area 206d including a center 206e of the circle of the diaphragm 206. Because 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 area including the center 206e. In this embodiment, the light reflecting portion 207 is disposed in a position that covers the center 206e, but it may also be disposed in a position that covers an area of ​​the diaphragm 206 that does not include the center 206e. The light reflecting portion 207 is formed, for example, from an aluminum vapor deposition film. The light reflecting portion 207 may also be a sheet-like member attached to the surface of the diaphragm 206 opposite the contact surface 206a.

[0030] The light-emitting element 202 emits light toward the inner surface 206b of the diaphragm 206 (strictly speaking, the light-reflecting portion 207). The upper surface of the light-reflecting portion 207 reflects the light emitted from the light-emitting element 202. That is, the upper surface of the light-reflecting portion 207 functions as a light-reflecting surface. In the following description, the reflection of light on the upper surface (i.e., the light-reflecting surface) of the light-reflecting portion 207 will simply be referred to as light being reflected by the light-reflecting portion 207. The light-reflecting portion 207 specularly reflects (in other words, specularly 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 portion 207 will be referred to as incident light 211, and the light after the incident light 211 is reflected will be referred to as reflected light 212.

[0031] In this embodiment, the light reflecting portion 207 is a separate member from the diaphragm 206. However, the light reflecting portion 207 may be configured as the same member as the diaphragm 206, with at least a portion of the inner surface 206b of the diaphragm 206 also serving as the light reflecting portion. Alternatively, a coating layer may be applied to the diaphragm 206, and the coating layer may serve as the light reflecting portion. For example, the entire inner surface 206b of the diaphragm 206 may have a high reflectivity that allows it to reflect light to an extent that can be detected by the light receiving element 204. Alternatively, only a region of the inner surface 206b of the diaphragm 206, which is the region that is reached by light emitted from the light emitting element 202, may have such a high reflectivity.

[0032] The light-emitting element 202 is positioned so as to emit light toward a region 207a of the light-reflecting portion 207 that includes a portion covering the center 206e of the diaphragm 206 when the diaphragm 206 is not in contact with the surface of the living body. When the diaphragm 206 is not in contact with the surface of the living body, the diaphragm 206 is flat. The light-emitting element 202 emits light toward a specific region (e.g., region 207a) of the light-reflecting portion 207. In this embodiment, as described above, an LED that emits diffused light is used as the light-emitting element 202. Therefore, the chestpiece 110 has an aperture portion 209 that narrows the light emitted from the light-emitting element 202. The aperture portion 209 allows only a portion of the light emitted from the light-emitting element 202 to enter the light-reflecting portion 207. In the example of FIG. 2A , the portion of the holding member 201 where the opening is formed corresponds to the aperture portion 209. In the present embodiment, a component that emits diffused light has been described as an example of the light-emitting element 202. However, instead, a laser diode or the like that emits linear light may be used as the light-emitting element 202, and the linear light may be emitted toward the region 207 a. When the light-emitting element 202 is a component that emits linear light, the diaphragm portion 209 may be omitted. In the present embodiment, the portion of the holding member 201 in which an opening is formed has been described as an example of the diaphragm portion 209. However, a one-sided diaphragm may be used instead of an opening. In that case, for example, a light-shielding wall for narrowing down one side (upper or lower side) of the light emitted from the light-emitting element 202 is provided instead of the opening.

[0033] The light-receiving element 204 is positioned to receive the reflected light 212. Specifically, the light-receiving element 204 is positioned at a location where the amount of reflected light 212 received changes due to 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 surface of the living body (i.e., when the diaphragm 206 is flat), it receives more of the reflected light 212 than 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. The principle behind this can be described later. The chestpiece 110 has an aperture 210 that narrows the light specularly reflected by the light reflecting portion 207. The diaphragm section 210 prevents diffusely reflected light from entering the light receiving element 204 and allows only at least a portion of the light from the light reflecting section 207 (i.e., the primarily reflected light) to reach the light receiving element 204. In the example of FIG. 2A , the portion of the holding member 201 where the opening is formed functions as the diaphragm section 210. In this embodiment, the portion of the holding member 201 where the opening is formed has been described as an example of the diaphragm section 210, but a one-sided diaphragm may be used instead of an opening. In that case, for example, a light-shielding wall for narrowing down one side (upper or lower side) of the light from the light reflecting section 207 is provided instead of the opening.

[0034] A housing 208 is attached to the outer periphery of the holding member 201. The housing 208 covers the light-emitting circuit board 203 and the light-receiving circuit board 205 and prevents ambient sound from entering the housing 208. The outer edges of the diaphragm 206, the holding member 201, and the housing 208 are generally aligned with one another in a plan view of the contact surface 206a of the diaphragm 206. In this embodiment, the housing 208 is made of metal, and the grounds of the circuit boards (e.g., the light-emitting circuit board 203 and the light-receiving circuit board 205) inside the chestpiece 110 are electrically connected to the housing 208. This stabilizes the ground potential.

[0035] By fixing the diaphragm 206 to the holding member 201, an internal space 213 surrounded by the diaphragm 206 and the holding member 201 is formed. The internal space 213 is sealed in order to prevent the light receiving element 204 from receiving any light other than that emitted by the light emitting element 202. Furthermore, the diaphragm 206 and the holding member 201 have a light-blocking property in order to prevent the light receiving element 204 from receiving any light other than that emitted by the light emitting element 202. In the example of FIG. 2A , a fixed portion 206c of the diaphragm 206 is fixed to the holding member 201. Alternatively, in the example of FIG. 2A , the fixed portion 206c of the diaphragm 206 may be fixed to the housing 208.

[0036] In the example of Fig. 2A, a configuration has been described in which the light-emitting circuit board 203 and the light-receiving circuit board 205 are held by a holding member 201 provided inside the housing 208. However, as shown in Fig. 2B, a configuration may also be adopted in which the light-emitting circuit board 203 formed integrally with the housing 208 holds the light-emitting unit 203, and a holding unit 221 formed integrally with the housing 208 holds the light-receiving circuit board 205. In such a configuration, the holding member 201 is omitted. The holding unit 220 has a light-shielding wall and functions as an aperture unit 209 that shapes the incident light 211. The holding unit 221 has a light-shielding wall and functions as an aperture unit 210 that restricts the reflected light 212 that reaches the light-receiving element 204.

[0037] 2A has been described as an example in which the light-emitting circuit board 203 and the light-receiving circuit board 205 are held by a holding member 201 provided inside the housing 208. However, as shown in Fig. 2C , a configuration may also be used in which a member 230 extending from the housing 208 presses the light-emitting circuit board 203 toward the holding member 201, thereby holding the light-emitting circuit board 203. Alternatively, as shown in Fig. 2C , a configuration may also be used in which a member 231 extending from the housing 208 presses the light-receiving circuit board 205 toward the holding member 201, thereby holding the light-receiving circuit board 205.

[0038] [Example of Operation of the Electronic Auscultation Device in the First Embodiment] An example of operation of the chestpiece 110 of the electronic auscultation device 100 in the first embodiment will be described with reference to Figures 3A and 3B. As shown in Figures 3A and 3B, the chestpiece 110 is used in contact with the biological surface 300, which is an example of the object to be measured. That is, during use, the contact surface 206a of the diaphragm 206 of the chestpiece 110 is in close contact with the biological surface 300, which is an example of the object to be measured. As a result, the biological surface 300, the diaphragm 206, and the light reflecting portion 207 vibrate together. Therefore, the chestpiece 110 detects the displacement of the upper surface of the light reflecting portion 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 physical movements, such as the heartbeat and breathing, of the person holding the biological surface 300.

[0039] 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 positioned so that when the diaphragm 206 is flat, the light-receiving element 204 receives more reflected light 212 than when the diaphragm 206 is vibrating. The light-receiving element 204 amplifies and outputs a photocurrent corresponding to the amount of light received. The peripheral circuit of the light-receiving circuit board 205 converts the photocurrent output from the light-receiving element 204 into a voltage, generates an output value as a displacement signal, and outputs the displacement signal to an external device. In this embodiment, the displacement signal refers to the output value of the light-receiving element 204, which reflects the state and deformation of the diaphragm 206 at any given time.

[0040] 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 portion 207 is represented by d1. As the biological surface 300 is displaced upward, the distance d1 decreases. Accordingly, the region 207a of the light-reflecting portion 207 where 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, less of the reflected light 212 reaches the light-receiving element 204, and the value of the displacement signal generated by the light-receiving circuit board 205 decreases. In the state shown in FIG. 3B, none of the reflected light 212 reaches the light-receiving element 204, so the value of the displacement signal is ideally zero.

[0041] Thus, in the chestpiece 110, the light-emitting element 202 and the light-receiving element 204 are arranged so that the amount of light reaching the light-receiving element 204 changes in accordance with the movement of the biological surface 300, the diaphragm 206, and the light-reflecting portion 207. Because the light-reflecting portion 207 displaces 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.

[0042] [Relationship Between the Displacement Amount of the Diaphragm and the Displacement Amount of the Position at which Reflected Light is Received in the Electronic Auscultation Device According to the First Embodiment] With reference to Figures 4A to 4F, the relationship between the displacement amount of the biological surface 300, the angle of incidence of the incident light 211, the angle of incidence of the reflected light 212, and the displacement amount of the position at which the light-receiving element 204 receives the reflected light 212 will be described. In each of Figures 4A to 4F, position 401 indicates the reference position of the top surface of the light reflecting unit 207. In this embodiment, the top surface of the light reflecting unit 207 when the diaphragm 206 is flat is defined as the reference position. Position 402 indicates the position at which the top surface of the light reflecting unit 207 is displaced upward from position 401 by a displacement amount d2. Because the displacement amount d2 of the light reflecting unit 207 is minute, the top surface of the light reflecting unit 207 is considered to be flat even when it is at position 402.

[0043] In each of Figures 4A to 4F, optical axis 403 indicates the optical axis of incident light 211. The angle of incidence of light emitted from the light-emitting element 202 and incident on the light reflecting portion 207 is represented by θ. The angle of incidence θ of the incident light 211 is defined by the angle between the optical axis 403 of the incident light 211 and the normal to the top surface of the light reflecting portion 207. The optical axis of reflected light 212 when the top surface of the light reflecting portion 207 is at position 401 is represented by optical axis 404. The optical axis of reflected light 212 when the top surface of the light reflecting portion 207 is at position 402 is represented by optical axis 405. Because the incident light 211 is specularly reflected by the top surface of the light reflecting portion 207, the reflection angle of the reflected light 212 is also θ. The optical axis 404 and the optical axis 405 are parallel to each other. The angle of incidence of the reflected light 212 on the light receiving element 204 is represented by φ. The incident angle φ of the reflected light 212 is defined by the angle between the optical axis 404 or 405 of the reflected light 212 and the normal to the light receiving surface of the light receiving element 204. In FIGS. 4A and 4B , the incident angle φ is 0°, so φ is not shown. The displacement amount of the position at which the light receiving element 204 receives the reflected light 212 when the top surface of the light reflecting portion 207 is displaced from position 401 to position 402 is represented as d3. The displacement amount d3 may be defined by the displacement amount from the position at which the light receiving element 204 receives the optical axis 404 to the position at which the light receiving element 204 receives the optical axis 405. In the following description, the ratio of the displacement amount d3 to the displacement amount d2 is represented as the displacement magnification G. In this case, the following relationship holds: G = 2 × sin θ / cos φ (Equation 1). 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 vice versa.

[0044] 4A and 4B illustrate 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 light-receiving element 204. In this case, Equation 1 becomes G=2×sin θ (Equation 2). As can be seen by comparing Fig. 4A and Fig. 4B, the displacement amount d3 increases as the incident angle θ increases.

[0045] 4C illustrates a case where the light receiving surface of the light receiving element 204 is perpendicular to the upper surface of the light reflecting portion 207. In this case, φ=90°−θ is satisfied, and therefore, Equation 1 becomes: G=2 (Equation 3).

[0046] 4D illustrates a case where the light receiving surface of the light receiving element 204 is parallel to the optical axis 403. In this case, φ=2×θ−90° is satisfied, and therefore, Equation 1 becomes G=1 / cos θ (Equation 4).

[0047] 4E illustrates a case where the light receiving surface of the light receiving element 204 is parallel to the upper surface of the light reflecting portion 207. In this case, φ=θ is satisfied, and therefore, Equation 1 becomes: G=2 tan θ (Equation 5).

[0048] Table 1 below shows the displacement magnification G when the incident angle θ is changed in various ways with respect to the incident angle φ in Figures 4A and 4C to 4E. In Table 1, the values ​​are rounded to the nearest hundredth. (Table 1)

[0049] The configuration example of FIG. 4F differs from the configuration example of FIG. 4A in that it further includes a lens 410 on the optical path of the reflected light 212. The lens 410 is located between the light reflecting portion 207 and the light receiving element 204. The lens 410 refracts the reflected light 212 in a direction away from the center of the light receiving element 204. This further increases the displacement amount d3, and therefore the displacement magnification G. In the configuration example of FIG. 4F, the lens 410 is added to the configuration example of FIG. 4A. The lens 410 may be added to any of the configuration examples of FIGS. 4C to 4E.

[0050] [Relationship between the displacement amount of the biological surface 300 and the displacement signal of the electronic auscultation device according to the first embodiment] The relationship between the displacement amount of the biological surface 300 and the displacement signal will be described with reference to Fig. 5. The displacement signal represents the voltage output from the optical receiver circuit board 205. A graph 500 in Fig. 5 represents the relationship between the displacement amount of the biological surface 300 and the displacement signal. The horizontal axis of the graph 500 represents the displacement amount of the biological surface 300, and represents the displacement signal generated by the optical receiver circuit board 205.

[0051] As described above, the displacement amount of the biological surface 300 is equal to the displacement amount d2 of the upper surface of the light reflecting portion 207. As shown in FIGS. 3A and 3B , as the displacement amount d3 of the reflected light 212 increases, the amount of the reflected light 212 that reaches the light receiving element 204 decreases monotonically and linearly. Therefore, when the value of the displacement signal is represented as Sd, the following equation is obtained: Sd=Vmax-k×d3 (Equation 6) 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 coefficient determined by the amplification factor of the amplifier circuit of the light receiving circuit board 205. By substituting Equation 1 into Equation 6, the following equation is obtained: Sd=Vmax-2k×d2×sin θ / cos φ (Equation 7) Therefore, as shown by graph 500, the displacement signal Sd decreases monotonically and linearly as the displacement amount 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 light receiving element 204, and therefore, even if the displacement amount d2 increases, the displacement signal Sd remains zero. Therefore, the proportionality coefficient k, the incident angle θ, and the incident angle φ are set so that the displacement amount d2 is within a range between 0 and dmax within the range in which the diaphragm 206 is expected to vibrate (referred to as the operating range of the diaphragm 206). As shown in graph 500, the light emitting element 202 and the light receiving element 204 are positioned so that the amount of light reaching the light receiving element 204 (the amount of received light) changes monotonically in response to movement of the light reflecting portion 207 in one direction within the operating range of the diaphragm 206. In the example of FIG. 5 , the light receiving element 204 is positioned so that the amount of received light monotonically decreases. However, the light receiving element 204 may also be positioned so that the amount of received light monotonically increases.

[0052] In Equation 7, the coefficient of d2, 2k × sin θ / cos φ = k × G, represents the sensitivity of the chestpiece 110. The incident angle θ can be greater than 0° and less than 90°. The incident angle φ can be greater than 0° and less than 90°. The greater the displacement factor G, the higher the sensitivity of the chestpiece 110. Therefore, the chestpiece 110 may be configured so that the displacement factor G is greater than 1, i.e., so that the displacement amount d3 is greater than the displacement amount d2. Furthermore, the chestpiece 110 may be configured so that the displacement factor G is greater than 1.5 or greater than 2. For example, the chestpiece 110 may satisfy the relationship 45°≦θ<90°, or may further satisfy the relationship 45°<θ<90°. Specifically, the incident angle θ may be 45°, 60°, or 70°. The incident angle φ may be 0°, 30°, 45°, 60°, or 70°.

[0053] In this embodiment, the light emitting element 202 and the light receiving element 204 are arranged so that all of the reflected light 212 reaches the light receiving element 204 (i.e., so that the displacement signal becomes Vmax) when the diaphragm 206 is flat. Alternatively, the light emitting element 202 and the light receiving element 204 may be arranged so that all of the reflected light 212 reaches the light receiving element 204 when the diaphragm 206 is in a position displaced downward from the flat position.

[0054] The chestpiece 110 according to the above-described embodiment can accurately detect the displacement of the biological surface 300. Specifically, in the above-described chestpiece 110, when the biological surface, which is an example of a measurement target, is in close contact with the diaphragm 206, a displacement signal is generated based on the displacement d2 of the biological surface vibrating integrally with the diaphragm 206. Therefore, regardless of the frequency at which the biological surface 300 vibrates, the displacement of the biological surface 300 can be accurately detected. For example, the displacement of the biological surface 300 due to low-frequency vibrations of approximately 10 Hz can also be accurately detected. Such low-frequency vibrations are included in sounds (e.g., heart sounds) generated by vibrations propagated from within the body due to heartbeats. In the chestpiece 110, the displacement signal does not change unless the diaphragm 206 is displaced. Therefore, ambient sounds and vibrations or accelerations due to movement of the chestpiece 110 are not detected as noise, resulting in output characteristics with a high S / N ratio.

[0055] [Hardware Configuration of the Electronic Auscultation Device in the First Embodiment] Referring to FIG. 6 , an example of the hardware configuration of the electronic auscultation device 100 in the first embodiment will be described. The electronic auscultation device 100 includes the chestpiece 110 and a sound output unit 610. The sound output unit 610 is implemented by multiple circuit elements mounted on a circuit board included in the grip unit 120. The multiple circuit elements include a processor. The processor constituting the sound output unit 610 transmits a sound signal based on a displacement signal generated by the chestpiece 110 to an external sound output device. The sound signal transmitted by the sound output unit 610 represents the body sound of a living body (e.g., a human) having a body surface 300, and is therefore also referred to as a biosignal. The sound signal is transmitted to a sound output device 620, such as earphones or headphones. The sound signal is also transmitted to a computer 630 (e.g., a personal computer, smartphone, tablet, etc.) simultaneously with the transmission to the sound output device 620. A user such as a doctor, nurse, or public health nurse can listen to the body sounds represented by the digitally converted sound signals using the sound output device 620 or the computer 630. The sound output device 620 is a wired or wireless earphone or headphone.

[0056] The sound output unit 610 has the components shown in FIG. 6 . Since the sound output unit 610 conforms to the earphones or headphones, it can transmit sound signals both wirelessly and via wired communication. The following describes the process by which the sound output device 620 outputs a sound signal via wired communication. The displacement signal output from the chestpiece 110 is filtered and amplified by the filter / amplifier 618 and supplied to the A / D converter 611 and the amplifier 615. The amplifier 615 further amplifies the output from the filter / amplifier 618 and supplies it to the wired communication unit 617. The wired communication unit 617 provides the amplified sound signal to the sound output device 620. The wired communication unit 617 is, for example, a 3.5 mm AUX terminal. The amplification gain of the amplifier 615 is adjusted by the volume adjustment unit 616. The sound output device 620 may be considered to constitute a part of the electronic auscultation device 100. In this case, the electronic auscultation device 100 includes a chestpiece 110 , a grip portion 120 , and a sound output device 620 .

[0057] Next, the process by which the sound output device 620 outputs a sound signal via wireless communication will be described. The A / D converter 611 digitizes the output from the filter / amplifier 618. The digital displacement signal is then amplified by the amplifier 612 and supplied to the encoder 613. The encoder 613 performs signal processing, such as data compression and encoding, on the amplified sound signal to generate sound data for wireless communication. The order of processing by the amplifier 612 and the encoder 613 may be reversed. Then, a wireless communication unit 614 compliant with a wireless communication standard such as Bluetooth (registered trademark) provides the processed sound data to the sound output device 620. The amplification gain of the amplifier 612 is adjusted by the volume adjustment unit 616. Although the electronic auscultation device 100 described above is capable of outputting a sound signal via both wireless and wired communication, it may also be capable of outputting a sound signal via only one of these communication methods.

[0058] The transmission of sound signals to the computer 630 is similar to the transmission of sound signals to the sound output device 620. The computer 630 can also visually display waveform data generated based on the sound signals. The waveform data may be generated by the computer 630 or by the electronic auscultation device 100. Furthermore, part or all of the signal processing and sound output processing by the electronic auscultation device 100 may be performed by an external device (e.g., the sound output device 620 or the computer 630).

[0059] The electronic auscultation device 100 according to the first embodiment described above can accurately detect displacement of the body surface 300 regardless of the frequency of vibration of the body surface 300. Therefore, the electronic auscultation device 100 enables good auscultation of both relatively low-frequency body sounds of about 10 Hz, such as heartbeat sounds emitted by the body due to heartbeats, and relatively high-frequency body sounds emitted by the body due to breathing.

[0060] [Details of an Example of Operation of the Electronic Auscultation Device in the First Embodiment] The operation of the chestpiece 110 of the electronic auscultation device 100 in the first embodiment will be described in more detail with reference to FIGS. 7A to 7D. FIGS. 7A and 7B show a state in which the diaphragm 206 is not pressed (i.e., flat). FIGS. 7C and 7D show a state in which the diaphragm 206 is pressed by the biological surface 300. In each of FIGS. 7A and 7C, the lower side shows a cross-sectional view of the chestpiece 110, and the upper side shows a plan view of the chestpiece 110. In the plan view, only the light-emitting element 202, the light-receiving element 204, the light-reflecting portion 207, the light-shielding wall 704, and the light-shielding wall 705 are shown to clarify the positional relationship of the components. FIGS. 7B and 7D are perspective views focusing on the light-emitting element 202, the light-receiving element 204, the light-reflecting portion 207, the light-shielding wall 704, and the light-shielding wall 705.

[0061] 7A to 7D, the light-shielding wall 704 having the opening 706 formed therein functions as the diaphragm 209 on the incident light 211 side, and the light-shielding wall 705 having the opening 707 formed therein functions as the diaphragm 210 on the reflected light 212 side. In particular, the portion of the light-shielding wall 704 above the upper edge of the opening 706 corresponds to the first diaphragm. Therefore, part of the light emitted by the light-emitting element 202 is blocked by the light-shielding wall 704 and does not reach the light-reflecting portion 207. Furthermore, at least part of the light specularly reflected by the light-reflecting portion 207 is blocked by the light-shielding wall 705, depending on the position of the light-reflecting portion 207. In this embodiment, both the openings 706 and 707 are rectangular. In the following description, of the four sides of each of openings 706 and 707, the side parallel to and closer to diaphragm 206 will be referred to as the lower side, the side parallel to and farther from diaphragm 206 will be referred to as the upper side, the side on the left side as viewed from light-emitting element 202 will be referred to as the left side, and the side on the right side as viewed from light-emitting element 202 will be referred to as the right side.

[0062] 7A to 7D, incident light 211 and reflected light 212 represent light fluxes that reach light receiving element 204. In Fig. 7B, some light 710 of the light emitted from light emitting element 202 passes through opening 706 of light-shielding wall 704 and is reflected by light reflecting portion 207 to become light 711, but is blocked by a portion of light-shielding wall 705 that is above reflected light 212 and does not reach light receiving element 204. The same is true in Fig. 7D.

[0063] 7A and 7B , the portion of the light reflecting portion 207 that is reached by the incident light 211 when the diaphragm 206 is not pressed by the biological surface 300 is referred to as the effective range 700. The effective range 700 is the portion of the light reflecting portion 207 that reflects light that reaches the light receiving element 204. When the diaphragm 206 is not pressed, the effective range 700 is equal to the range reached by light from the light emitting element 202. In this embodiment, the effective range 700 is a rectangular area. The periphery of the effective range 700 is referred to as the boundary line of the effective range 700. The boundary line of the effective range 700 is located between the effective range 700 and an area other than the effective range 700. In the following description, part of the boundary line will also be referred to as the boundary line.

[0064] Of the four line segments that make up the boundary of the effective range 700, the line segment that includes the farthest position in the x-axis direction from the light-emitting element 202 is referred to as the far boundary line 700a. The portion of the incident light 211 that reaches the far boundary line 700a is referred to as the far incident light 211a. The far incident light 211a means that it includes the portion of the optical path from the light-emitting element 202 to the light reflecting portion 207 that is the longest. The angle of incidence of the incident light 211 to the light reflecting portion 207 reaches a maximum value 703a at a position on the far boundary line 700a.

[0065] Of the four line segments that form the boundary of the effective range 700, the line segment that includes the position closest to the light-emitting element 202 in the x-axis direction is referred to as the near boundary line 700b. The portion of the incident light 211 that reaches the near boundary line 700b is referred to as the near incident light 211b. The near incident light 211b means that it includes the portion of the optical path from the light-emitting element 202 to the light reflecting portion 207 that is shortest. The angle of incidence of the incident light 211 to the light reflecting portion 207 reaches a minimum value 703b at a position on the near boundary line 700b. Of the light emitted from the light-emitting element 202, light that is not included between the far incident light 211a and the near incident light 211b is attenuated by being reflected multiple times by the light-shielding wall 704.

[0066] Of the four line segments that make up the boundary of the effective range 700, the two line segments other than the far boundary 700a and the near boundary 700b are referred to as lateral boundary lines 700c and 700d. The lateral boundary line 700c is located on the right side of the effective range 700 as seen from the light-emitting element 202, and the lateral boundary line 700d is located on the left side of the effective range 700 as seen from the light-emitting element 202.

[0067] As shown in FIGS. 7A and 7B , the region of the light receiving element 204 formed by the reflected light 212 specularly reflected by the light reflecting portion 207 is referred to as the light irradiation region 701. The light irradiation region 701 is a portion of the light receiving element 204 where light emitted from the light emitting element 202 and specularly reflected by the light reflecting portion 207 reaches. In addition to the light specularly reflected by the light reflecting portion 207, scattered light may also reach the light receiving element 204. However, in this embodiment, the light irradiation region 701 is defined as the region formed by the specularly reflected light. The amount of light reaching the light receiving element 204 is proportional to the area of ​​the light irradiation region 701. In this embodiment, the light irradiation region 701 is a rectangular region. The periphery of the light irradiation region 701 is referred to as the boundary line of the light irradiation region 701. The boundary line of the light irradiation region 701 is located between the light irradiation region 701 and the region other than the light irradiation region 701.

[0068] Of the four line segments constituting the boundary of the light irradiation area 701, the line segment formed by light narrowed by the aperture section 209 and specularly reflected by the light reflecting section 207 is referred to as the lower boundary 701a. Of the four line segments constituting the boundary of the light irradiation area 701, the line segment opposite the lower boundary 701a is referred to as the upper boundary 701b. The lower boundary 701a is an example of a boundary formed by light narrowed by the aperture section 209 and specularly reflected by the light reflecting section 207. The lower boundary 701a is a boundary that moves in response to the displacement of the contact surface 206a, as described below. In this embodiment, the movement of the lower boundary 701a changes the area of ​​the light irradiation area 709, and the output of the light receiving element 204 changes. This allows for accurate measurement of the displacement of the object to be measured. The upper boundary 701b is an example of a boundary that does not move in response to the displacement of the contact surface 206a and whose length does not change even when the contact surface 206a is displaced. Of the four line segments that make up the boundary of the light-irradiated region 701, the two line segments other than the lower boundary 701a and the upper boundary 701b are referred to as lateral boundary lines 701c and 701d. The lateral boundary line 701c is located on the right side of the light-irradiated region 701 as seen from the light-emitting element 202, and the lateral boundary line 701d is located on the left side of the light-irradiated region 701 as seen from the light-emitting element 202. The lateral boundary lines 701c and 701d are examples of boundary lines that do not move in response to displacement of the contact surface 206a, but whose lengths change when displacement of the contact surface 206a occurs, as will be described later.

[0069] Light passing through the opening 706 along the upper edge of the opening 706 is specularly reflected by the light reflecting portion 207 and then reaches the lower boundary line 701a of the light irradiation region 701 of the light receiving element 204 without being blocked by the light-shielding wall 705. Therefore, the upper edge of the opening 706 defines the lower boundary line 701a of the light irradiation region 701. On the other hand, light passing through the opening 706 along the lower edge of the opening 706 is specularly reflected by the light reflecting portion 207 and then blocked by the light-shielding wall 705, and does not reach the light receiving element 204. Therefore, the lower edge of the opening 706 does not define the light irradiation region 701. Therefore, the near incident light 211b is not narrowed by the diaphragm portion 209. Alternatively, light passing through the opening 706 along the lower edge of the opening 706 may be specularly reflected by the light reflecting portion 207 and then reaches the light receiving element 204 without being blocked by the light-shielding wall 705. In this case, the lower side of the opening 706 defines the light irradiation area 701. In this configuration, the displacement signal in Fig. 5 remains constant as the displacement of the diaphragm 206 ranges from zero to a predetermined value. Thereafter, when the lower side of the opening 706 no longer defines the light irradiation area 701, the displacement signal begins to decrease monotonically.

[0070] Light that passes through the opening 706, is specularly reflected by the light reflecting portion 207, and then passes through the opening 707 along the upper edge of the opening 707 reaches the upper boundary line 701b of the light irradiation region 701 of the light receiving element 204. Therefore, the upper edge of the opening 707 defines the upper boundary line 701b of the light irradiation region 701. In other words, the upper edge of the opening 707 is an example of an aperture section that narrows down the light specularly reflected by the light reflecting portion 207. On the other hand, light does not pass through the portion along the lower edge of the opening 707 because it is blocked by the light-shielding wall 704. Therefore, the lower edge of the opening 707 does not define the light irradiation region 701.

[0071] 7A , the lateral boundary lines 701c and 701d of the light-illuminated region 701 are defined by the right and left sides of the opening 707. Alternatively, the lateral boundary lines 701c and 701d of the light-illuminated region 701 may be defined by the right and left sides of the opening 706.

[0072] The reflected light of the distant incident light 211a is referred to as the lower-end reflected light 212a. The lower-end reflected light 212a is the light of the reflected light 212 located lowest in the z-axis direction (i.e., the portion closest to the diaphragm 206). The lower-end reflected light 212a reaches a lower boundary line 701a of the light irradiation area 701. The lower boundary line 701a is formed by light that is narrowed by the diaphragm unit 209 and specularly reflected by the light reflecting unit 207. The lower-end reflected light 212a is away from each side of the opening 705. In other words, the lower-end reflected light 212a is not narrowed by the diaphragm unit 210. In the configurations of FIGS. 7A and 7B , the lower boundary line 701a includes the position of the light irradiation area 701 closest to the diaphragm 206 in the normal direction (i.e., the z-axis direction) of the diaphragm 206 when not pressed by the biological surface 300. 7A and 7B , the lower boundary line 701 a includes a position in the light irradiation area 701 where light reaches with the maximum reflection angle at the light reflecting portion 207. This maximum reflection angle is equal to the maximum incident angle 703 a. Furthermore, in the configurations of FIGS. 7A and 7B , the lower boundary line 701 a includes a position farthest from the light emitting element 202 in a plan view of the diaphragm 206 when it is not pressed.

[0073] The reflected light of the near incident light 211b is referred to as the upper edge reflected light 212b. The upper edge reflected light 212b is the light of the reflected light 212 located at the uppermost position in the z-axis direction (i.e., the portion farthest from the diaphragm 206). The upper edge reflected light 212b reaches the upper boundary line 701b of the light irradiation area 701. In the configurations of FIGS. 7A and 7B , the upper boundary line 701b includes the position in the light irradiation area 701 farthest from the diaphragm 206 in the normal direction (i.e., the z-axis direction) of the diaphragm 206 when not pressed. Also, in the configurations of FIGS. 7A and 7B , the upper boundary line 701b includes the position in the light irradiation area 701 reached by the light with the smallest reflection angle at the light reflecting portion 207. This minimum reflection angle is equal to the minimum incident angle 703b. Furthermore, in the configurations of FIGS. 7A and 7B, the upper boundary line 701b includes the position closest to the light emitting element 202 in a plan view of the diaphragm 206 in an unpressured state.

[0074] 7C and 7D , when the diaphragm 206 is pressed by the biological surface 300, the positions of the effective range 700, far boundary 700a, near boundary 700b, light irradiation region 701, lower boundary 701a, and upper boundary 701b all change. The portion of the reflected light 212 farthest from the light-emitting element 202 in the x-axis direction is referred to as the lower-end reflected light 212a. The lower-end reflected light 212a reaches the lower boundary 701a of the light irradiation region 701. As described above, the lower boundary 701a is defined by the upper edge of the opening 706 of the diaphragm unit 209 on the light-emitting element 202 side. The lower boundary 701a moves in response to the displacement of the contact surface 206a due to elastic deformation of the diaphragm 206. This changes the area of ​​the light irradiation region 701 and the output of the light-receiving element 204, as described below. 4A to 4F. That is, the lower boundary line 701a is displaced by a displacement magnification G relative to the displacement d2 of the diaphragm 206. The position at which the farthest portion of the reflected light 212 from the light-emitting element 202 (within three-dimensional space, regardless of the x-axis direction) reaches the light-receiving element 204 is also displaced by the displacement magnification G.

[0075] As shown in FIGS. 7A to 7D , the upper boundary line 701b is defined by the portion of the light-shielding wall 705 that is above the reflected light 212, and is a boundary line that does not move in response to displacement of the contact surface 206a and whose length does not change even when displacement of the contact surface 206a occurs. The portion of the light-shielding wall 704 that is below the incident light 211 does not need to block the light emitted from the light-emitting element 202. For example, the portion of the light-shielding wall 704 that is below the incident light 211 does not need to be provided. Furthermore, the lower boundary line 701a is defined by the portion of the light-shielding wall 704 that is above the incident light 211. Therefore, the portion of the light-shielding wall 705 that is below the reflected light 212 does not need to block the light specularly reflected by the light reflecting portion 207. For example, the portion of the light-shielding wall 705 that is below the reflected light 212 does not need to be provided.

[0076] [Changes in the Reach Range of Reflected Light in the Electronic Auscultation Device According to the First Embodiment] With reference to Fig. 7E, changes in the light irradiation area 701 formed by the reflected light 212 reaching the light receiving surface of the light receiving element 204 will be described. Fig. 7E shows a plan view of the light receiving surface of the light receiving element 204. The left side of Fig. 7E shows the position of the light irradiation area 701 when the diaphragm 206 is not pressed. The right side of Fig. 7E shows the position of the light irradiation area 701 when the diaphragm 206 is pressed by the biological surface 300.

[0077] To explain the directions, a coordinate system CS' is attached to Figure 7E. The coordinate system CS' is a two-dimensional Cartesian coordinate system having mutually orthogonal x'-axis and y'-axis. The y'-axis coincides with the y-axis of the coordinate system CS. The x'-axis is parallel to the xz plane of the coordinate system CS. In the following description, the positive direction of the x'-axis will be referred to as the upper side, and the negative direction of the x'-axis will be referred to as the lower side.

[0078] The surface of the light receiving element 204 that faces the internal space 213 is the light receiving surface. The light receiving element 204 detects the amount of light that reaches the light receiving surface. As described above, in this embodiment, the light receiving element 204 is a single light receiving element. A line sensor or an area sensor may be used instead of a single light receiving element. The light receiving surface may have a rectangular shape. Of the four sides of the light receiving surface, the side that is parallel to the diaphragm 206 and closer to the diaphragm 206 is referred to as side 204a.

[0079] The area of ​​the light irradiation region 701 is determined by a lower boundary line 701a, an upper boundary line 701b, and side boundary lines 701c and 701d. As shown in Figure 7E, the lower boundary line 701a of the light irradiation region 701 changes in the x'-axis direction in response to the displacement of the contact surface 206a. On the other hand, the upper boundary line 701b and the side boundary lines 701c and 701d do not substantially move in response to the displacement of the contact surface 206a. Therefore, the area of ​​the light irradiation region 701 changes in response to the movement of the lower boundary line 701a. The length of the upper boundary line 701b does not change even when the contact surface 206a is displaced. On the other hand, the lengths of the side boundary lines 701c and 701d change when the contact surface 206a is displaced.

[0080] As the area of ​​the light-irradiated region 701 changes, the signal output from the light-receiving element 204 also changes. Specifically, the greater the displacement of the contact surface 206a of the diaphragm 206 from its flat state, the shorter the distance between the lower boundary line 701a and the upper boundary line 701b (i.e., the lengths of the lateral boundary lines 701c and 701d), and the smaller the area of ​​the light-irradiated region 701. Therefore, the greater the displacement of the diaphragm 206 from its flat state, the less light the light-receiving element 204 receives. Accordingly, the signal output from the light-receiving element 204 also decreases. As shown in FIG. 7E , the amount of movement of the lower boundary line 701a accompanying the movement of the light-reflecting portion 207 is greater than the amount of movement of the upper boundary line 701b accompanying the movement of the light-reflecting portion 207.

[0081] 7E, the change in the light irradiation area 701 in the x'-axis direction is larger than the change in the light irradiation area 701 in the y'-axis direction. Therefore, in order to increase the dynamic range of the light receiving element 204, it is preferable to make the width of the light receiving element 204 in the x'-axis direction larger than the width of the light receiving element 204 in the y'-axis direction. More specifically, it is preferable to make the width of the light receiving element 204 in the x'-axis direction three times or more the width of the light receiving element 204 in the y'-axis direction.

[0082] [First Modification of the Electronic Auscultation Device of the First Embodiment] A first modification of the chestpiece 110 will be described with reference to Figures 8A and 8B. Differences from Figures 7B and 7D will be mainly described in Figures 8A and 8B. The chestpiece 110 according to the first modification does not include the light-shielding wall 705. Therefore, the chestpiece 110 does not include the diaphragm portion 210.

[0083] Light passing through the opening 706 along the upper edge of the opening 706 is specularly reflected by the light reflecting portion 207 and then reaches the lower boundary line 701a of the light irradiation area 701 of the light receiving element 204. Therefore, the upper edge of the opening 706 defines the lower boundary line 701a of the light irradiation area 701. On the other hand, as shown in FIG. 8A , light 810 passing through the opening 706 along the lower edge of the opening 706 is specularly reflected by the light reflecting portion 207 and becomes light 811, which reaches the outside of the light receiving element 204. Therefore, the lower edge of the opening 706 does not define the light irradiation area 701. The same is true in FIG. 8B . The upper boundary line 701b of the light irradiation area 701 is defined by a line segment that forms the edge of the light-receiving area of ​​the light receiving element 204 (specifically, the upper edge of the light-receiving area of ​​the light receiving element 204). 8A and 8B , the lateral boundary lines 701c and 701d of the light irradiation area 701 are defined by line segments (specifically, the right and left sides of the light reception area of ​​the light receiving element 204) that form the edges of the light reception area of ​​the light receiving element 204. In other words, instead of this, the lateral boundary lines 701c and 701d of the light irradiation area 701 may be defined by the right and left sides of the opening 706.

[0084] [Second Modification of the Electronic Auscultation Device in the First Embodiment] A second modification of the chestpiece 110 will be described with reference to Figures 8C to 8E. In Figures 8C to 8E, differences from Figures 7B, 7D, and 5 will be mainly described.

[0085] Light passing through the opening 706 along the lower edge of the opening 706 is specularly reflected by the light reflecting portion 207 and then reaches the light irradiation region 701 of the light receiving element 204 without being blocked by the light-shielding wall 705. Therefore, the lower edge of the opening 706 defines the upper boundary line 701b of the light irradiation region 701. On the other hand, as shown in Figure 8C, light 820 passing through the opening 706 along the upper edge of the opening 706 is specularly reflected by the light reflecting portion 207 to become light 821, and then is blocked by the light-shielding wall 705 and does not reach the light receiving element 204. Therefore, the upper edge of the opening 706 does not define the light irradiation region 701. The same is true in Figure 8D.

[0086] Light that passes through the opening 706, is specularly reflected by the light reflecting portion 207, and then passes through the opening 707 along the lower edge of the opening 707 reaches the lower boundary line 701a of the light irradiation area 701 of the light receiving element 204. Therefore, the lower edge of the opening 707 defines the lower boundary line 701a of the light irradiation area 701. On the other hand, since the light is blocked by the light-shielding wall 704, the light does not pass through the portion along the lower edge of the opening 707. Therefore, the upper edge of the opening 707 does not define the light irradiation area 701.

[0087] 8C and 8D, when the diaphragm 206 is pressed by the biological surface 300, the positions of the effective range 700, far boundary 700a, near boundary 700b, light irradiation area 701, lower boundary 701a, and upper boundary 701b each change. As described above, the upper boundary 701b is defined by the lower side of the opening 706 of the diaphragm section 209 on the light-emitting element 202 side. The upper boundary 701b moves in response to the displacement of the contact surface 206a. On the other hand, the lower boundary 701a and the lateral boundary lines 701c and 701d do not substantially move in response to the displacement of the contact surface 206a. The upper boundary 701b displaces at a displacement magnification G relative to the displacement amount d2 of the diaphragm 206. The displacement magnification G has the same value as that in Table 1 above.

[0088] [Relationship between the displacement amount of the biological surface 300 and the displacement signal of the electronic auscultation device according to the second modification] The relationship between the displacement amount of the biological surface 300 and the displacement signal will be described with reference to Fig. 8E. The displacement signal represents the voltage output from the optical receiver circuit board 205. A graph 800 in Fig. 8E represents the relationship between the displacement amount of the biological surface 300 and the displacement signal. The horizontal axis of the graph 800 represents the displacement amount of the biological surface 300, and represents the displacement signal generated by the optical receiver circuit board 205.

[0089] When the displacement of the biological surface 300 is zero, the displacement signal has a value corresponding to the area of ​​the light-irradiated region 701 shown in Fig. 8C. As the displacement of the contact surface 206a increases, the upper end reflected light 212b moves away from the diaphragm 206, and the area of ​​the light-irradiated region 701 increases monotonically and linearly. That is, the amount of light emitted by the light-emitting element that reaches the light-receiving element 204 increases monotonically and linearly. As a result, the displacement signal output from the light-receiving element 204 also increases monotonically and linearly. Thereafter, when the upper end reflected light 212b reaches the light-shielding wall 705, the displacement signal becomes constant.

[0090] [Third Modification of the Electronic Auscultation Device of the First Embodiment] In the chestpiece 110 according to the third modification, the light-shielding wall 705 is omitted. Therefore, the chestpiece 110 does not have the diaphragm 210. Light passing through the opening 706 along its lower edge is specularly reflected by the light reflecting portion 207 and then reaches the upper edge of the light-irradiated region 701 of the light-receiving element 204. Therefore, the lower edge of the opening 706 defines the upper edge of the light-irradiated region 701. On the other hand, light passing through the opening 706 along its upper edge is specularly reflected by the light reflecting portion 207 and then reaches the outside of the light-receiving element 204. Therefore, the upper edge of the opening 706 does not define the light-irradiated region 701. The lower edge of the light-irradiated region 701 is defined by the lower edge of the light-receiving element 204. Furthermore, the left and right edges of the light-irradiated region 701 are defined by the left and right edges of the light-receiving element 204. Alternatively, the left and right sides of the light irradiation area 701 may be defined by the left and right sides of the opening 706 .

[0091] [Fourth Modification of the Electronic Auscultation Device in the First Embodiment] A fourth modification of the chestpiece 110 will be described with reference to Figures 9A and 9B. In Figures 9A and 9B, differences from Figures 7A and 7C will be mainly described.

[0092] 9A and 9B, the chestpiece 110 further includes a lens 900 between the light-emitting element 202 and the light reflecting portion 207. The lens 900 converts the diffused light emitted by the light-emitting element 202 into parallel light. Because this parallel light reaches the light reflecting portion 207, the chestpiece 110 can eliminate the aperture portion 209 on the incident light 211 side.

[0093] 7A and 7C, the range of light reaching the light receiving element 204 (i.e., the light irradiation area 701) changes in the x′-axis direction as the light reflecting portion 207 moves.

[0094] [Summary of First Embodiment and First to Fourth Modifications] Figure 9C is a diagram summarizing whether the upper and lower sides of openings 706 and 707 define light irradiation area 701 in each of the first embodiment and first to fourth modifications. The "Cross-sectional configuration" in Figure 9C simply illustrates the cross-sectional configuration of light-emitting element 202, light-receiving element 204, light reflecting portion 207, opening 706, and opening 707 in each configuration. Of the upper and lower sides of openings 706 and 707, the sides that define light irradiation area 701 are indicated by black triangles, and the sides that do not define light irradiation area 701 are indicated by white triangles. The "Change in Displacement Signal" in Figure 9C indicates whether the signal monotonically decreases as in graph 500 in Figure 5 or monotonically increases as in graph 800 in Figure 8E.

[0095] In the above-described embodiment, the normal to the light receiving surface of the light receiving element 204 is inclined with respect to the z-axis direction (i.e., the normal direction to the diaphragm 206). Alternatively, the normal to the light receiving surface of the light receiving element 204 may coincide with the z-axis direction. In other words, the light receiving surface is parallel to the diaphragm 206.

[0096] In the above-described embodiment, the chestpiece 110 includes only one light-emitting element 202. Alternatively, the chestpiece 110 may include multiple light-emitting elements 202. Light emitted by the multiple light-emitting elements 202 may be reflected by the light reflecting portion 207 and reach the light-receiving element 204. The light-receiving element 204 may detect the displacement of the diaphragm 206 based on the total amount of light received by the multiple light-receiving elements 204. The chestpiece 110 may include multiple light-receiving elements 204. Each of the multiple light-receiving elements 204 may receive light emitted from a separate light-emitting element 202 and reflected by the light reflecting portion 207. The displacement of the diaphragm 206 may be detected based on the total amount of light received by the multiple light-receiving elements 204.

[0097] In the above-described embodiment, the electronic auscultation device 100 generates a displacement signal (i.e., a signal representing the displacement of the diaphragm 206) based on the amount of light emitted from the light-emitting element 202, reflected by the light-reflecting element 207, and received by the light-receiving element 204. Alternatively, the electronic auscultation device 100 may detect the displacement signal in another manner based on the light received by the light-receiving element 204. For example, the light-emitting element 202 may emit laser light toward the light-reflecting element 207. The laser light reflected by the light-reflecting element 207 reaches the light-receiving element 204. The position at which the laser light reaches the light-receiving element 204 varies depending on the displacement of the diaphragm 206. Therefore, the electronic auscultation device 100 may detect the displacement signal based on the position of the light received by the light-receiving element 204. When the light-emitting element 202 emits laser light, the chestpiece 110 does not need to include the apertures 209 and 210. When the light emitting element 202 emits laser light, the light receiving element 204 may be a two-dimensional area sensor or a one-dimensional line sensor.

[0098] Second Embodiment [Hardware Configuration of an Electronic Auscultation Device in the Second Embodiment] An example configuration of an electronic auscultation device 1000 according to the second embodiment will be described with reference to Figures 10 to 13K. The following mainly describes the differences from the electronic auscultation device 100 according to the first embodiment. The appearance of the electronic auscultation device 1000 is similar to that of the electronic auscultation device 100 described with reference to Figures 1A and 1B. The modifications described in the first embodiment may also be applied to the second embodiment.

[0099] The hardware configuration of the electronic auscultation device 1000 will be described with reference to Figure 10. The difference between Figure 10 and Figure 6 is that the electronic auscultation device 1000 includes a chestpiece 1010 and a sound output unit 1020 instead of the chestpiece 110 and sound output unit 610 of the electronic auscultation device 100. The electronic auscultation device 1000 is composed of the chestpiece 1010 and the sound output unit 1020 included in the grip unit 120 (Figures 1A and 1B). The chestpiece 1010 has a displacement detection unit 1011 and a vibration detection unit 1012. Similar to the electronic auscultation device 100, the displacement detection unit 1011 is composed of main components including a light-emitting element 202, a light-receiving element 204, and a light-reflecting unit 207. The displacement detection unit 1011 generates a displacement signal (i.e., a signal representing the displacement of the diaphragm 206) based on the amount of light emitted from the light-emitting element 202, reflected by the light-reflecting element 207, and received by the light-receiving element 204. Alternatively, the displacement detection unit 1011 may detect the displacement signal in another manner based on the light received by the light-receiving element 204. For example, the light-emitting element 202 may emit a laser beam toward the light-reflecting element 207. The laser beam reflected by the light-reflecting element 207 reaches the light-receiving element 204. The position at which the laser beam reaches the light-receiving element 204 varies depending on the displacement of the diaphragm 206. Therefore, the displacement detection unit 1011 may detect the displacement signal based on the position of the light received by the light-receiving element 204. When the light-emitting element 202 emits a laser beam, the chestpiece 1010 does not need to include the apertures 209 and 210. When the light emitting element 202 emits laser light, the light receiving element 204 may be a two-dimensional area sensor or a one-dimensional array sensor.

[0100] The vibration detection unit 1012 detects air vibrations caused by the displacement of the diaphragm 206. The vibration detection unit 1012 is also called a sound detection unit because it detects sounds represented by air vibrations. The vibration detection unit 1012 is configured, for example, by a capacitor-type microphone 1101 ( FIG. 11C ). The vibration detection unit 1012 generates a sound signal representing the detected air vibrations. The sound signal may be an electric signal (for example, a voltage signal). The displacement signal generated by the displacement detection unit 1011 and the sound signal generated by the vibration detection unit 1012 are each supplied to the sound output unit 1020.

[0101] The sound output unit 1020 performs signal processing on the displacement signal and sound signal supplied from the chestpiece 1010 in the same manner as the sound output unit 610 of the electronic auscultation device 100, and transmits the signals to an external device (e.g., the sound output device 620 or the computer 630) outside the sound output unit 1020. The frequency bands to which the displacement detection unit 1011 and the vibration detection unit 1012 have high sensitivity may differ. For example, the displacement detection unit 1011 can detect vibrations (e.g., heartbeat sounds) in a low-frequency band (e.g., 100 Hz or less) with better sensitivity than the vibration detection unit 1012. On the other hand, the vibration detection unit 1012 can detect vibrations (e.g., respiratory sounds) in a high-frequency band (e.g., 100 Hz or more) with better accuracy than the displacement detection unit 1011. Therefore, since the sound output unit 1020 can output both the displacement signal and the sound signal, the electronic auscultation device 1000 can accurately detect vibrations in a wide frequency band.

[0102] The sound output unit 1020 includes an output selection unit 1021 in addition to the components included in the sound output unit 610 of the electronic auscultation device 100. The output selection unit 1021 selects whether the displacement signal or the sound signal supplied from the chestpiece 1010 is to be output to the outside. For example, when the transmission destination is the sound output device 620, the output selection unit 1021 outputs only the selected one of the displacement signal and the sound signal. When the transmission destination is the computer 630, the output selection unit 1021 may output only the selected one of the displacement signal and the sound signal, or may output both the displacement signal and the sound signal. In this way, the sound output unit 1020 can selectively output the displacement signal or the sound signal to the outside.

[0103] The operation unit 123 of the electronic auscultation device 1000 receives a user's designation regarding whether to output a displacement signal or an audio signal. In this embodiment, the operation unit 123 shown in FIG. 1A is provided with a mode switching button 123c. In response to pressing the mode switching button 123c, the output selection unit 1021 switches the signal output to the external device between the displacement signal and the audio signal. For example, when auscultating heartbeat sounds, the user operates the mode switching button 123c provided on the operation unit 123 to select the heartbeat sound mode, which is one of the auscultation modes. On the other hand, when auscultating breath sounds, the user operates the mode switching button 123c provided on the operation unit 123 to select the breath sound mode, which is one of the auscultation modes. Information regarding the operation mode designated by the user is sent to the output selection unit 1021. Based on this operation mode information, the output selection unit 1021 selects whether to output a displacement signal representing the displacement detected by the displacement detection unit 1011 or an audio signal detected by the vibration detection unit 1012. The operation unit 123 also has volume adjustment buttons 123a and 123b for adjusting the gain of the displacement signal output by the electronic auscultation device 100. The volume adjustment buttons 123a and 123b are used to adjust the volume of the audio output by the electronic auscultation device 100. Furthermore, the display unit 122 of the electronic auscultation device 1000 has an LED as an indicator that indicates whether the signal currently selected to be output is a displacement signal or an audio signal. The lighting state of this LED allows the user to visually determine whether the operating mode is the heartbeat sound mode or the breath sound mode. The heartbeat sound mode and the breath sound mode are each an example of an auscultation mode.

[0104] The output selection unit 1021 controls the wireless communication unit 614 and the wired communication unit 617 to determine the type of signal to be output externally. Alternatively, the output selection unit 1021 may determine whether a displacement signal or a sound signal is to be supplied to the A / D converter 611 and the amplifier 615. Furthermore, in the example of Fig. 10, the sound output unit 1020 includes the output selection unit 1021, but instead, the chestpiece 1010 may include the output selection unit 1021. The output selection unit 1021 in the chestpiece 1010 may determine the type of signal to be supplied to the sound output unit 1020.

[0105] [Chestpiece Configuration of the Electronic Auscultation Device in the Second Embodiment] An example of the structure of the chestpiece 1010 will be described with reference to Figures 11A to 13K. Figure 11A is a plan view of the chestpiece 1010. Figure 11B is an enlarged cross-sectional view of the chestpiece 1010 taken along line A-A in Figure 11A. Figure 11C is an enlarged cross-sectional view of the chestpiece 1010 taken along line B-B in Figure 11A. Figure 12A is an exploded perspective view of the chestpiece 1010, with each component separated. Figure 12B is a perspective view showing the shape of the sealed space 1100. Figures 13A to 13C are perspective views of the lower holding member 1105 viewed from various angles. Figures 13D to 13F are perspective views of the upper holding member 1106 viewed from various angles. Figure 13G is a perspective view of the base holding member 1104 viewed from a certain angle. 13H to 13K are perspective views of the lower holding member 1105 and the upper holding member 1106 when coupled together, as viewed from various angles. In particular, FIG. 13H is a perspective view viewed from an angle where the light-emitting element 202 is visible through the opening 706, and FIG. 13I is a perspective view viewed from an angle where the light-receiving element 204 is visible through the opening 707. In FIG. 11A, the light-emitting element 202, the light-receiving element 204, the light reflecting portion 207, and the microphone 1101 are depicted as visible for ease of understanding, but these components are hidden by the housing 208. In FIGS. 11B and 11C, cross sections of the same components are indicated by the same hatching, and cross sections of different components are indicated by different hatching for ease of understanding. A mechanism for attaching the chestpiece 1010 to the grip portion 120 is omitted from FIGS. 11A to 13K.

[0106] In addition to the components included in the chestpiece 110 of the electronic auscultation device 100, the chestpiece 1010 further includes a microphone 1101, a sealing member 1102, and a relay circuit board 1103. As described above, the microphone 1101 constitutes the vibration detection unit 1012.

[0107] The relay circuit board 1103 is connected to the light-emitting circuit board 203 by a lead wire (not shown). The relay circuit board 1103 transmits a control signal to the light-emitting circuit board 203 to instruct it to emit light and supplies power through this lead wire. The relay circuit board 1103 is also connected to the light-receiving circuit board 205 by a lead wire (not shown). The relay circuit board 1103 receives a displacement signal from the light-receiving circuit board 205 through this lead wire and supplies power to the light-receiving circuit board 205. The relay circuit board 1103 is also connected to the microphone 1101 by a lead wire (not shown). The relay circuit board 1103 receives a sound signal from the microphone 1101 through this lead wire and supplies power to the microphone 1101. The relay circuit board 1103 is also connected to a circuit board in the grip portion 120 by a cable (not shown). The relay circuit board 1103 transmits displacement signals and sound signals to the circuit board in the grip portion 120 via this cable, receives control signals for controlling the operation of the chestpiece 110 from the circuit board in the grip portion 120, and receives a supply of power. A hole 208a is formed in the housing 208 for passing a cable connecting the relay circuit board 1103 and the circuit board in the grip portion 120. In this specification, unless otherwise specified, a "hole" refers to a through-hole that penetrates the member in which the hole is formed. On the other hand, a "recess" refers to a hole that does not penetrate the member in which the recess is formed.

[0108] The holding member 201 is composed of a base holding member 1104, a lower holding member 1105, and an upper holding member 1106. A diaphragm 206 is attached to the base holding member 1104 so as to cover the lower surface of the base holding member 1104. The outer periphery of the diaphragm 206 is folded back to form a recess, and the diaphragm 206 is attached to the base holding member 1104 by fitting a protrusion on the outer periphery of the base holding member 1104 into this recess. Alternatively, the diaphragm 206 may be attached to the base holding member 1104 by, for example, adhesive bonding. Because there is a gap between the lower surface of the base holding member 1104 and the diaphragm 206, the diaphragm 206 can be displaced relative to the lower surface of the base holding member 1104. The lower surface of the base holding member 1104 has a recess near its center so as not to hinder the displacement of the diaphragm 206.

[0109] A housing 208 is attached to the base holding member 1104 so as to cover the upper surface of the base holding member 1104. The base holding member 1104 has a screw thread or a thread groove on its outer periphery, and the housing 208 has a screw groove or a thread on the inside of its lower end. These screw threads and the thread groove fit together to attach the housing 208 to the base holding member 1104. Alternatively, the housing 208 may be attached to the base holding member 1104 by, for example, adhesive bonding. The housing 208 covers the light-emitting element 202, light-emitting circuit board 203, light-receiving element 204, light-receiving circuit board 205, and microphone 1101 attached to the holding member 201, and has the function of insulating ambient sound so that it is not detected as noise.

[0110] Two more holding members (a lower holding member 1105 and an upper holding member 1106) are arranged on the base holding member 1104. The lower holding member 1105 is located on the opposite side of the base holding member 1104 from the diaphragm 206 in the z direction. A recess 1105d formed on the underside of the lower holding member 1105 fits into a protrusion 1104d formed on the upper surface of the base holding member 1104, and the lower holding member 1105 is aligned with the base holding member 1104.

[0111] The upper holding member 1106 is disposed above the base holding member 1104 and the lower holding member 1105 in the z direction. The upper holding member 1106 is located on the opposite side of the base holding member 1104 from the diaphragm 206. The lower holding member 1105 is located between the upper holding member 1106 and the base holding member 1104. A convex portion 1106a formed on the lower surface of the upper holding member 1106 fits into a hole 1105b formed in the lower holding member 1105, thereby aligning the upper holding member 1106 with the lower holding member 1105.

[0112] The relay circuit board 1103 is disposed on the upper holding member 1106. A screw (not shown) passing through a hole 1103a formed in the relay circuit board 1103 and a hole 1106c formed in the upper holding member 1106 is engaged with a screw hole 1104c formed in the base holding member 1104. In the illustrated example, three screw holes are formed in the base holding member 1104, and a screw passing through the relay circuit board 1103 and the upper holding member 1106 is engaged with each of these screw holes. This fixes the lower holding member 1105, the upper holding member 1106, and the relay circuit board 1103 to the base holding member 1104. The method for fixing the lower holding member 1105, the upper holding member 1106, and the relay circuit board 1103 to the base holding member 1104 is not limited to this, and they may be fixed using an adhesive, for example.

[0113] The light-emitting element 202 is inserted into a hole formed by the engagement of the upper holding member 1106 and the lower holding member 1105. The light-receiving element 204 is arranged to cover the hole formed by the engagement of the upper holding member 1106 and the lower holding member 1105. The microphone 1101 is arranged in a hole 1104b formed in the base holding member 1104. A seal member 1102 is arranged between the microphone 1101 and the base holding member 1104 to seal the gap between these members, improving the airtightness of the sealed space described below. In addition, a convex portion 1106b formed on the underside of the upper holding member 1106 is arranged above the hole 1104b in the base holding member 1104. The convex portion 1106b may press the microphone 1101 downward (i.e., toward the diaphragm 206). The microphone 1101 is positioned so as not to overlap the optical path of light (i.e., incident light 211 and reflected light 212) traveling from the light-emitting element 202 to the light-receiving element 204 via the light-reflecting portion 207 when viewed in a planar view relative to the diaphragm 206 (i.e., when viewed from the positive z-axis).

[0114] A T-shaped hole 1104a is formed near the center of the base holding member 1104. A hole 1105a is also formed near the center of the lower holding member 1105. Incident light 211 passes through holes 1104a and 1105a from the light-emitting element 202 to the light reflecting portion 207. Reflected light 212 also passes through holes 1104a and 1105a from the light reflecting portion 207 to the light-receiving element 204. Thus, no other components are located on the optical path of the light (i.e., the incident light 211 and the reflected light 212) traveling from the light-emitting element 202 to the light-receiving element 204 via the light reflecting portion 207. The base holding member 1104 covers the entire inner surface 206b of the diaphragm 206 except for the area where the light reflecting portion 207 is fixed.

[0115] The upper holding member 1106 has a light-shielding wall 1106d extending in a direction intersecting the diaphragm 206 (the y-z plane in the example of FIG. 11B ). In particular, the portion of the light-shielding wall 1106d above the upper edge of the opening 706 corresponds to the first diaphragm portion. The lower holding member 1105 has a light-shielding wall 1105c extending in a direction along the diaphragm 206 (the x-y plane in the example of FIG. 11B ). The light-shielding wall 1106d and the light-shielding wall 1105c form the diaphragm portion 209 on the incident light 211 side. In other words, the light-shielding wall 1106d and the light-shielding wall 1105c each block a portion of the light emitted by the light-emitting element 202. A portion of the light-shielding wall 1105c may extend into the hole 1104a in the base holding member 1104. This allows the diaphragm portion 209 to be closer to the light reflecting portion 207, thereby reducing the spread of the incident light 211. Furthermore, the upper holding member 1106 has a light-shielding wall 1106e that protrudes downward in the z-direction at a position where the light reflected by the light reflecting portion 207 reaches. The lower holding member 1105 has a light-shielding wall 1105e at a position where the light reflected by the light reflecting portion 207 reaches. The light-shielding wall 1106e and the light-shielding wall 1105e form an aperture portion 210 on the side of the reflected light 212. That is, the light-shielding wall 1106e and the light-shielding wall 1105e each block a portion of the light specularly reflected by the light reflecting portion 207. The light-shielding wall 1106d provided on the upper holding member 1106 and the light-shielding wall 1105c provided on the lower holding member 1105 not only serve as an aperture portion that blocks the incident light 211 and the reflected light 212, but also serve to narrow the sealed space. That is, the light-shielding walls 1105c and 1106d narrow the volume of the sealed space (internal space), thereby increasing the rate of volume change described below, and as a result, the sensitivity of the microphone 1101 can be improved.

[0116] In the second embodiment, the diaphragm 206, the light reflecting portion 207, the base holding member 1104, the lower holding member 1105, the upper holding member 1106, the light emitting element 202, the light receiving element 204, and the microphone 1101 define a sealed space 1100. Therefore, the space facing the inner surface 206b of the diaphragm 206 is a sealed space. A sealed space is a space sealed against specific substances. In other words, a sealed space is a space in which the inflow of specific substances from an external space or the external environment and the outflow of specific substances to an external space or the external environment are restricted. Therefore, there are no passages, such as gaps or holes, connecting the sealed space 1100 to the outside. The substances to be sealed may vary depending on the environment in which the electronic auscultation device 1000 is used. For example, if the electronic auscultation device 1000 is used at atmospheric pressure, the substance to be sealed may be a gas (e.g., air), and if the electronic auscultation device 1000 is used underwater, the substance to be sealed may be a liquid (e.g., water).

[0117] 11B and 11C , the space facing the inner surface 206b of the diaphragm 206 and surrounded by the hatched components is the sealed space 1100. The portion of the lower holding member 1105 that defines the sealed space 1100 includes the above-mentioned light-shielding wall 1105c. The portion of the upper holding member 1106 that defines the sealed space 1100 includes the above-mentioned light-shielding wall 1106d. When a gap exists between the light-emitting element 202 and the holding member 201, the sealed space 1100 is further defined by the light-emitting circuit board 203. Similarly, when a gap exists between the light-receiving element 204 and the holding member 201, the sealed space 1100 is further defined by the light-receiving circuit board 205. When a gap exists between the microphone 1101 and the holding member 201, the sealed space 1100 is further defined by the seal member 1102.

[0118] The sealed space 1100 does not have to be sealed when the electronic auscultation device 100 is not in use. For example, the diaphragm 206 and the base holding member 1104 may not be in close contact when the electronic auscultation device 100 is not in use, but may be in close contact when the diaphragm 206 is pressed against the surface of a living body, thereby forming the sealed space 1100.

[0119] The sound detection surface 1101a of the microphone 1101 faces the sealed space 1100. This allows the microphone 1101 to detect air vibrations in the internal space 212 caused by displacement of the contact surface 206a of the diaphragm 206. The microphone 1101 generates a sound signal representing the air vibrations.

[0120] Specifically, the portion of diaphragm 206 that comes into contact with the surface of the living body is made of a sheet-like flexible material. Diaphragm 206 separates sealed space 1100 from the outside of chestpiece 1010. Diaphragm 206 has the property of deforming in response to an external force applied to diaphragm 206 (for example, a force from the surface of the living body) and returning to its original shape when the external force is removed. Due to this property, the air pressure in sealed space 1100 changes in response to vibrations transmitted from the surface of the living body to diaphragm 206. Sound detection surface 1101a of microphone 1101 vibrates in response to the air pressure in sealed space 1100, and microphone 1101 converts the vibrations of sound detection surface 1101a into an electrical signal.

[0121] The inner surface 206b of the diaphragm 206 and the sound detection surface 1101a of the microphone 1101 face the sealed space 1100, so that the microphone 1101 can efficiently detect sound signals corresponding to the displacement of the surface of the living body.

[0122] The change in air pressure in sealed space 1100 in response to the vibration of diaphragm 206 becomes greater as the volume of sealed space 1100 becomes smaller. Accordingly, the sound detected by microphone 1101 becomes louder. Therefore, in this embodiment, sealed space 1100 is configured so that the volume of sealed space 1100 is smaller than the volume of the internal space of chestpiece 110. That is, in this embodiment, sealed space 1100 does not face housing 208, and is separated from the space facing the inner surface of housing 208. However, it goes without saying that the space facing the inner surface of housing 208 may also be the sealed space.

[0123] In this embodiment, the interior space of the chestpiece 110 other than the sealed space 1110 is not sealed, but may be sealed if, for example, the electronic auscultation device 1000 requires waterproofing or dustproofing. For example, as shown in FIG. 11B , the housing 208 is formed with a hole 208a for passing a cable. The gap between this hole 208a and the cable is sealed with a sealant, sealing the interior space of the chestpiece 110 and making it airtight against water or dust. Furthermore, if a screw is used to fasten the housing 208 to the base holding member 1104 other than the hole 208a, sealing the gap between the thread and the groove with a sealant can also improve airtightness.

[0124] In this embodiment, the space facing the inner surface 206b of the diaphragm 206 is an enclosed space 1100, but for example, holes or gaps may be formed to the extent that the sensitivity does not decrease in the frequency band of the object to be measured.

[0125] In this embodiment, the space facing the inner surface 206b of the diaphragm 206 is sealed using the base holding member 1104, the lower holding member 1105, and the upper holding member 1106. Alternatively, this space may be sealed using parts of these holding members, or other parts. Furthermore, to improve the adhesion between the multiple components that define the sealed space 1100, a buffer member may be disposed between two adjacent components. For example, a buffer member may be disposed in the gap at the contact point between the light-emitting circuit board 203 and the holding member 201, the gap at the contact point between the light-receiving circuit board 205 and the holding member 201, or the gap at the contact point between the diaphragm 206 and the holding member 201. This can improve the sealing performance of the sealed space 1100.

[0126] [Sound-insulating configuration of the electronic auscultation device according to the second embodiment] The microphone 1101 can detect not only air vibrations generated in the sealed space 1100 but also sounds transmitted through the housing 208 from outside the chestpiece 1010. For this reason, the housing 208 is preferably made of a material with excellent sound-insulating properties.

[0127] The sound transmission loss of the housing 208 is calculated by a function that takes as input the frequency of the sound, the angle of incidence of the sound, and the surface density of the material of the housing 208. When the angle of incidence of the sound is perpendicular, the frequency of the sound is f [Hz] and the surface density of the material of the housing 208 is σ [kg / m ２ ], the sound transmission loss TL [dB] of the housing 208 is: TL = 18 × log １０ (σ×f)−44 (Equation 8) The areal density of the material of the housing 208 is calculated by multiplying the density of the material of the housing 208 by the thickness of the housing 208.

[0128] The surface density of the housing 208 and the transmission loss at various frequencies when the housing 208 is 1.5 mm thick and made of brass, stainless steel, aluminum, or polycarbonate ABS are shown in Table 2 below. Polycarbonate ABS is an example of a resin. (Table 2)

[0129] From Table 2, it can be seen that metal materials have better sound insulation properties than resin materials. Therefore, it is desirable that the housing 208 be made of a metal material. The surface density of the housing 208 may be greater than the surface density of the diaphragm. Specifically, the surface density of the housing 208 is 5 kg / m ２ It may be 10 kg / m or more, and even 10 kg / m ２ On the other hand, the holding member 201 may be made of a resin material in order to reduce the weight and cost of the chestpiece 1010.

[0130] 14A to 16C, several modified examples of chestpiece 1010 will be described. The explanations for each of the drawings in Figures 14A to 16C are the same as those for each of the drawings in Figures 11A to 11C, and therefore, redundant explanations will be omitted.

[0131] The modified example shown in Figures 14A to 14C differs from the second embodiment described above in Figures 11A to 11C in the position of the microphone 1101. In a plan view of the diaphragm 206 (i.e., when viewed from the positive z-axis), the microphone 1101 is positioned so as to overlap the optical path of light (i.e., incident light 211 and reflected light 212) traveling from the light-emitting element 202 to the light-receiving element 204 via the light-reflecting portion 207. However, because the microphone 1101 is positioned above this optical path in the z-axis direction (positive z-axis direction), it does not block this optical path. The microphone 1101 is positioned between the light-emitting element 202 and the light-receiving element 204 in the x-axis direction. The sound detection surface 1101a of the microphone 1101 faces the sealed space 1100, which faces the inner surface 206b of the diaphragm 206. By arranging the microphone 1101 in the above position, the volume of the sealed space 1100 can be reduced, and the vibration of the diaphragm 206 can be detected by the microphone 1101 with high precision.

[0132] 15A to 15C differs from the second embodiment described above in FIGS. 11A to 11C in that the chestpiece 1010 further includes a light-transmitting member 1501. The light-transmitting member 1501 has the property of transmitting light emitted by the light-emitting element 202. For example, the light-transmitting member 1501 is made of glass, acrylic, polystyrene, or the like.

[0133] 15A to 15C, the hole 1104a in the base holding member 1104 is sealed by the light-transmitting member 1501 and the lower holding member 1105. Therefore, a sealed space 1502 is defined by the diaphragm 206, the base holding member 1104, the lower holding member 1105, the light-transmitting member 1501, the microphone 1101, and the seal member 1102. The inner surface 206b of the diaphragm 206 faces this sealed space 1502. On the other hand, the light-emitting element 202 and the light-receiving element 204 do not face this sealed space 1502. In this modified example, the sound detection surface 1101a of the microphone 1101 also faces the sealed space 1502, which faces the inner surface 206b of the diaphragm 206.

[0134] Light-transmitting member 1501 is disposed on the optical path of light (i.e., incident light 211 and reflected light 212) traveling from light-emitting element 202 to light-receiving element 204 via light-reflecting portion 207. However, because light-transmitting member 1501 is light-transmitting, displacement detection unit 1011 can still detect the displacement of diaphragm 206. Furthermore, because the volume of sealed space 1502 is smaller than the volume of sealed space 1100, microphone 1101 can detect the vibration of diaphragm 206 with even greater accuracy.

[0135] [Another Modification of the Chestpiece Configuration of the Electronic Auscultator in the Second Embodiment] The modification shown in Figures 16A to 16C differs from the embodiment shown in Figures 14A to 14C above in the position of the microphone 1101 and in that the chestpiece 1010 further includes light-transmitting members 1601 and 1602. The microphone 1101 is positioned so as to overlap the optical path of light (i.e., the combined light of incident light 211 and reflected light 212) traveling from the light-emitting element 202 to the light-receiving element 204 via the light-reflecting portion 207 in a plan view of the diaphragm 206 (i.e., when viewed from the positive z-axis). The microphone 1101 is positioned above this optical path (in the positive z-axis direction) and therefore does not block it. For example, the microphone 1101 may be positioned between the light-emitting element 202 and the light-receiving element 204 in three-dimensional space.

[0136] The light-transmitting members 1601 and 1602 have the property of transmitting light emitted by the light-emitting element 202. For example, the light-transmitting members 1601 and 1602 are made of glass, acrylic, polystyrene, or the like.

[0137] 16A to 16C, the gap between the light-shielding walls 1106d and 1105c that constitute the diaphragm section 209 on the incident light side is sealed by a light-transmitting member 1601. Furthermore, the gap between the light-shielding walls 1106e and 1105e that constitute the diaphragm section 210 on the reflected light side is sealed by a light-transmitting member 1602. Therefore, a sealed space 1603 is defined by the diaphragm 206, the base holding member 1104, the lower holding member 1105, the light-transmitting members 1601 and 1602, the microphone 1101, and the sealing member 1102. The inner surface 206b of the diaphragm 206 faces this sealed space 1603. On the other hand, the light-emitting element 202 and the light-receiving element 204 do not face this sealed space 1603. In the modified example shown in FIGS. 16A to 16C, the sound detection surface 1101 a of the microphone 1101 also faces the sealed space 1603 that faces the inner surface 206 b of the diaphragm 206 .

[0138] The light-transmitting member 1601 is disposed on the optical path of light traveling from the light-emitting element 202 toward the light-reflecting portion 207 (i.e., incident light 211). The light-transmitting member 1601 is disposed on the optical path of light traveling from the light-reflecting portion 207 toward the light-receiving element 204 (i.e., reflected light 212). However, because the light-transmitting members 1601 and 1602 are translucent, the displacement detection unit 1011 can still detect the displacement of the diaphragm 206. Furthermore, because the volume of the sealed space 1603 is smaller than the volume of the sealed space 1100, the microphone 1101 can detect the vibration of the diaphragm 206 with even greater accuracy. In this embodiment, an example has been described in which the chestpiece 1010 includes both the light-transmitting member 1601 and the light-transmitting member 1602, but a configuration including only one of them is also possible.

[0139] [Relationship between the volume of the sealed space in the chestpiece of the electronic auscultation device in the second embodiment and the sensitivity of the microphone] The relationship between the volume of the sealed space facing the inner surface 206b of the diaphragm 206 and the sensitivity of the microphone 1101 will be specifically described with reference to Table 3 below. (Table 3)

[0140] Assume that the upper limit of the displacement of the operating range of the diaphragm 206 (i.e., the range in which the diaphragm 206 is expected to vibrate) is 1 mm. When the diaphragm 206 is displaced from a flat state to this upper limit of the displacement, the volume of the internal space of the chestpiece 1010 changes by, for example, 680 mm. ３ is.

[0141] The volume of the internal space of the chest piece 1010 is, for example, 17005 mm ３ Therefore, the volume change rate of the internal space when the diaphragm 206 changes to its upper limit is 680 / 17005≒4%. The volume of the sealed space 1100 described with reference to FIGS. 11A to 11C is, for example, 2085 mm ３ Therefore, the volume change rate of the sealed space 1100 due to the diaphragm 206 changing to its upper limit is 680 / 2085≒33%. The volume of the sealed space 1502 described in FIG. 15B and FIG. 15C is, for example, 1021 mm ３Therefore, the volume change rate of sealed space 1502 when diaphragm 206 moves to its upper limit is 680 / 1021 ≈ 67%. By making only a portion of the internal space of chestpiece 1010 a sealed space facing inner surface 206b of diaphragm 206, the volume change rate of this sealed space increases, and the sensitivity of microphone 1101 increases. For example, the sealed space may be defined so that the volume change rate of the sealed space when diaphragm 206 moves to the upper limit of its operating range is 30%.

[0142] [Circuit Configuration of Electronic Auscultation Device in Second Embodiment] Next, an example of the circuit configuration of the electronic auscultation device 1000 according to the second embodiment will be described with reference to Fig. 17A. The circuit configuration in Fig. 17A is a diagram showing in more detail the hardware configuration in Fig. 10.

[0143] As described above with reference to FIGS. 11A to 11C , the chestpiece 1010 includes a light-emitting element 202, a light-receiving element 204, and a microphone 1101. Furthermore, in the example of FIG. 17A , the chestpiece 1010 includes a three-axis acceleration sensor 1750. The acceleration sensor 1750 is a sensor that measures three-dimensional acceleration. The acceleration sensor 1750 is a sensor for detecting motion of the electronic auscultation device 1000, for example, detecting that the electronic auscultation device 1000 has been lifted by a user. In other words, the acceleration sensor 1750 is used to determine whether the electronic auscultation device 1000 is in use. In this embodiment, the acceleration sensor 1750 is included in the chestpiece 1010, but it may also be included in the grip portion 120 instead of the chestpiece 1010. Furthermore, if a different configuration is adopted to determine the use state of the electronic auscultation device 1000, the acceleration sensor 1750 need not be included.

[0144] 1A , the grip unit 120 includes a display unit 122, an operation unit 123, a power switch 124, and a connector 125. The grip unit 120 further includes a microcontroller 1700, a power supply unit 1710, a UART integrated circuit 1720, a diaphragm displacement signal processing unit 1730, and a microphone signal processing unit 1740. The multiple circuit elements included in the grip unit 120 may be mounted on the same circuit board included in the grip unit 120, or may be distributed and mounted on multiple circuit boards.

[0145] The microcontroller 1700 is a control means that controls the overall operation of the electronic auscultation device 1000. In FIG. 17A , the electronic auscultation device 1000 includes one or more microcontrollers 1700. The microcontroller 1700 includes a processor 1701, a nonvolatile memory 1702, a Bluetooth® circuit 1703, and a RAM 1704. The processor 1701 controls the operation of the electronic auscultation device 1000 by executing programs stored in the nonvolatile memory 1702. The nonvolatile memory 1702 is a storage means for storing programs that define the operation of the electronic auscultation device 1000 and various setting data, and retains the stored contents even without external power. The Bluetooth circuit 1703 is a control unit that controls the wireless communication unit 614, which complies with the Bluetooth wireless communication standard. The wireless communication unit 614 includes an antenna for wireless communication. In FIG. 17A , the microcontroller 1700 includes a built-in Bluetooth circuit 1703; however, the Bluetooth circuit 1703 may be external to the microcontroller 1700. The RAM 1704 is a storage unit that temporarily stores programs and various setting data read from the nonvolatile memory 1702. The microcontroller 1700 is implemented by multiple circuit elements mounted on a circuit board included in the grip unit 120. The microcontroller 1700 transmits a sound signal based on a displacement signal generated by the light receiving element 204 to an external sound output device via the wireless communication unit 614 or the wired communication unit 617. The sound output device 620 is, for example, a wired or wireless earphone or headphone. The microcontroller 1700 can transmit the sound signal to the sound output device 620 as well as to a computer 630 (e.g., a personal computer, smartphone, tablet, etc.). A doctor, nurse, or public health nurse can listen to the body sounds represented by the digitally converted sound signals using the sound output device 620 or the computer 630. The displacement signal output from the light receiving element 204 is filtered and amplified by a diaphragm displacement signal processing unit 1730 (described later) and supplied to an A / D converter 611.The A / D converter 611 digitizes the output from the diaphragm displacement signal processing unit 1730. The digital displacement signal is then subjected to signal processing, such as data compression and encoding, by the microcontroller 1700 using an encoder in accordance with a communication standard, and converted into sound data for wireless communication. This conversion to sound data is, for example, conversion to Pulse Code Modulation (PCM) format. The wireless communication unit 614, which complies with a wireless communication standard such as Bluetooth (registered trademark), then transmits the PCM-formatted sound data to the sound output device 620. Upon receiving the sound data, the sound output device 620 outputs sound corresponding to the sound data. While the electronic auscultation device 1000 described above is capable of transmitting sound data via both wireless and wired communication, it may also be capable of transmitting sound data via only one of these communication methods. Transmission of sound data to the computer 630 is similar to transmission of sound data to the sound output device 620. The computer 630 can also visually display waveform data generated based on the received sound data. The waveform data may be generated by the computer 630 or by the electronic auscultation device 1000. In addition, a part or all of the signal processing and sound output processing by the electronic auscultation device 1000 may be performed by an external device (e.g., the sound output device 620 or the computer 630).

[0146] The UART integrated circuit 1720 is connected to both the microcontroller 1700 and the connector 125 (specifically, its data terminal). The UART integrated circuit 1720 performs communication in accordance with the UART standard. The UART integrated circuit 1720 and the connector 125 function as the wired communication unit 617. The microcontroller 1700 may be able to communicate with an external device via a wired connection through the UART integrated circuit 1720 and the connector 125. The UART integrated circuit 1720 may also be connected to a power supply terminal of the connector 125. A voltage VBUS may be applied to the UART integrated circuit 1720 from an external device (e.g., a charger or a computer 630) connected to the connector 125 through the power supply terminal of the connector 125. The UART integrated circuit 1720 may be able to operate using the voltage VBUS as its operating voltage.

[0147] The power supply unit 1710 includes a battery 1711, a charging integrated circuit 1712, a boost converter 1713, a voltage regulator 1714, a load switch 1715, and a voltage regulator 1716. The power supply unit 1710 supplies power to a plurality of circuit elements included in the electronic auscultation device 1000. The power supply unit 1710 may supply power at a plurality of different voltages. Alternatively, the power supply unit 1710 may supply power at a single voltage and may drop the voltage at a stage preceding each circuit element to an appropriate operating voltage.

[0148] The battery 1711 stores electrical energy used by the electronic auscultation device 1000. The battery 1711 may have a function of cutting off the current when the current flowing through the battery 1711 exceeds a threshold. The charging integrated circuit 1712 is an integrated circuit (IC) that controls charging to and discharging from the battery 1711. For example, the charging integrated circuit 1712 charges the battery 1711 using electrical energy supplied from an external device, such as a charger connected to the connector 125 or the computer 630. The charging integrated circuit 1712 also supplies the electrical energy stored in the battery 1711 to the boost converter 1713. The voltage provided by the charging integrated circuit 1712 is referred to as voltage VBAT. The voltage VBAT is, for example, 3.7 V.

[0149] The boost converter 1713 boosts a DC voltage to another DC voltage. The boost converter 1713 is also called a DC / DC converter. The boost converter 1713 boosts the voltage VBAT supplied from the charging integrated circuit 1712 to a voltage V0. The voltage V0 is, for example, 6.8 V. The voltage regulator 1714 generates and outputs a voltage of a specific value. The voltage regulator 1714 may be a linear regulator, also called a low dropout regulator (LDO). The voltage regulator 1714 generates an operating voltage for some circuit elements of the electronic auscultation device 1000. The voltage generated by the voltage regulator 1714 is referred to as voltage V1. The voltage regulator 1714 may generate an operating voltage for the microcontroller 1700; for example, voltage V1 is 3.3 V. The operating voltage of the acceleration sensor 1750 is also voltage V1. 17A , voltage V1 is applied to each of microcontroller 1700 and acceleration sensor 1750. Power is supplied to microcontroller 1700 and acceleration sensor 1750 from voltage regulator 1714 of power supply unit 1710. Voltage regulator 1714 outputs voltage V1 when a voltage higher than voltage V1 is applied to its input terminal. Therefore, voltage regulator 1714 outputs voltage V1 when voltage V0 is supplied from boost converter 1713.

[0150] The load switch 1715 is a switch that switches between on (conducting state) and off (non-conducting state) in response to a control signal from the microcontroller 1700. The voltage regulator 1716 generates and outputs a voltage of a specific value. The voltage regulator 1716 may be a linear regulator or an LDO. The voltage regulator 1716 generates an operating voltage for some circuit elements of the electronic auscultation device 1000. The voltage generated by the voltage regulator 1716 is represented as voltage V2. The voltage regulator 1716 may generate an operating voltage for the light-emitting element 202 and the light-receiving element 204; for example, voltage V2 is 5.8 V. In the example of FIG. 17A , voltage V2 is applied to each of the light-emitting element 202 and the light-receiving element 204. Power is supplied to the light-emitting element 202 and the light-receiving element 204 from the voltage regulator 1716 of the power supply unit 1710. The voltage regulator 1716 outputs voltage V2 when a voltage higher than voltage V2 is applied to its input terminal. Therefore, the voltage regulator 1716 outputs the voltage V2 when the load switch 1715 is on. The voltage regulator 1716 does not output the voltage V2 when the load switch 1715 is off. When the voltage regulator 1716 does not output the voltage V2, the potential of the output terminal of the voltage regulator 1716 is the ground potential.

[0151] The diaphragm displacement signal processor 1730 processes the diaphragm displacement signal to generate a sound signal representing sound transmitted from the surface of the living body to the diaphragm 206, and outputs this sound signal to the microcontroller 1700. Specifically, the diaphragm displacement signal processor 1730 extracts components of a specific frequency band contained in the diaphragm displacement signal to generate a sound signal. As described below, the extracted components of the specific frequency band include components in a 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 in response to the amount of light reaching the light-receiving element 204. The diaphragm displacement signal may also be simply referred to as a displacement signal. The amount of light reaching the light-receiving element 204 varies depending on 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 diaphragm displacement signal may also be a signal generated and output by the light-receiving element 204 in response to the position of light reaching the light-receiving element 204. Even when realized using a laser diode, the diaphragm displacement signal still represents the displacement of the diaphragm 206. The sound signal generated by the diaphragm displacement signal processing unit 1730 based on the diaphragm displacement signal is output in the heartbeat sound mode, and therefore will be referred to as a heartbeat sound signal in the following description. The heartbeat sound signal is also a type of diaphragm displacement signal, as it represents the displacement of the diaphragm 206 (specifically, its components in a specific frequency band).

[0152] The diaphragm displacement signal processing unit 1730 includes a buffer circuit 1731, a high-pass filter (HPF) 1732, and amplifier circuits 1733 and 1734 with low-pass filters on the signal path between the light-receiving element 204 and the microcontroller 1700. These circuit elements are connected in series. The diaphragm displacement signal processing unit 1730 receives the diaphragm displacement signal from the light-receiving element 204 and outputs a heartbeat sound signal to the microcontroller 1700.

[0153] The buffer circuit 1731 receives a diaphragm displacement signal from the light receiving element 204 and outputs the diaphragm displacement signal to the HPF 1732. The buffer circuit 1731 converts the impedance of the signal path between the light receiving element 204 and the HPF 1732. For example, the output impedance of the buffer circuit 1731 is lower than the output impedance of the light receiving element 204. The operating power of the buffer circuit 1731 is supplied from the voltage regulator 1716.

[0154] The HPF 1732 attenuates low-frequency components (i.e., frequency components lower than a specific cutoff frequency) of the diaphragm displacement signal received from the buffer circuit 1731 and passes high-frequency components (i.e., frequency components higher than the cutoff frequency), thereby outputting the resulting signal to the amplifier circuit 1733. In this embodiment, the HPF 1732 attenuates components of at least less than 10 Hz from the diaphragm displacement signal received from the buffer circuit 1731, so the cutoff frequency of the HPF 1732 is set to, for example, 10 Hz. However, the cutoff frequency may be greater than 10 Hz, for example, 15 Hz or 20 Hz. The cutoff frequency may also be greater than or equal to 10 Hz and less than 20 Hz. Therefore, the HPF 1732 removes or attenuates components of at least less than 10 Hz from the diaphragm displacement signal received from the buffer circuit 1731.

[0155] The HPF 1732 is disposed on the signal path between the light receiving element 204 and the microcontroller 1700 and removes or attenuates low-frequency noise contained in the diaphragm displacement signal. The low-frequency noise contained in the diaphragm 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 components caused by the user's shaking of the electronic stethoscope device 1000. The low-frequency noise may also include changes in the DC component caused by the diaphragm 206 being pressed against the biological surface. Such low-frequency noise has a significantly larger amplitude than the components originating from vibrations transmitted from the biological surface to the diaphragm 206 (hereinafter referred to as biological components). Therefore, by amplifying the diaphragm displacement signal with suppressed low-frequency noise, biological components can be appropriately acquired within the dynamic range of the amplifier circuit. Note that a bandpass filter that removes at least components below 10 Hz may be used instead of the HPF 1732.

[0156] Referring to Figures 17B to 17H, the effect of attenuating components below 10 Hz from the diaphragm displacement signal (a signal generated and output by the light receiving element 204 in response to the amount of light reaching the light receiving element 204) will be described. Graph 1771 in Figure 17B shows the change over time of the diaphragm displacement signal when only heartbeat sounds are generated without camera shake. The diaphragm displacement signal shown in graph 1771 is the diaphragm displacement signal output from node 1735, located on the signal path between the buffer circuit 1731 and the HPF 1732, and is acquired and visualized by the microcontroller 1700. As shown in Figure 17B, the amplitude of the biosignal of the heartbeat sound is only a few mV, which is very small compared to the dynamic range of the output voltage of the light receiving element (approximately 5 V). The portion indicated by the dotted circle in Figure 17B is the first heartbeat sound, but it is difficult to accurately extract the heartbeat sound from the signal as is, and therefore it must be amplified by an amplifier circuit. Graph 1772 in Fig. 17C shows the change over time of the diaphragm displacement signal when only hand vibration is generated without generating heartbeat sounds. The diaphragm displacement signal in graph 1772 is the diaphragm displacement signal output from node 1735 located on the signal path between buffer circuit 1731 and HPF 1732, and is acquired and visualized by microcontroller 1700. For example, when a user auscultates while holding an electronic stethoscope in their hand, as shown in Fig. 17C, the amplitude of the signal of the hand vibration component may reach an amplitude of several hundred mV in some cases, which is much larger than the amplitude of the signal of the heartbeat sound component.

[0157] In order to measure small-amplitude biological vibrations, the diaphragm displacement signal must be amplified. Graph 1773 in Figure 17D shows a signal waveform in which the diaphragm displacement signal is amplified 100 times by an amplifier circuit when hand shake and heartbeat sound are generated. Graph 1773 in Figure 17D shows the output signal from the light receiving element 204, amplified 100 times by the amplifier circuit 1733 without passing through the HPF 1732, and acquired and visualized by the microcontroller 1700. If the signal is amplified using a large gain by the amplifier circuit without removing the hand shake component signal, as shown by the solid circle in graph 1773, the signal value partially exceeds the dynamic range, resulting in peak cutoff. Furthermore, as shown by the dotted circle in graph 1773, in the signal waveform of graph 1773, the heartbeat sound is buried in the hand shake component signal, making it difficult to identify which component is the heartbeat sound. On the other hand, graph 1774 in FIG. 17E shows an example in which the amplification factor of the amplifier circuit is set low so as not to exceed the dynamic range. Graph 1774 in FIG. 17E shows the waveform of a diaphragm displacement signal when hand shake and heartbeat sound are present, amplified 25 times by the amplifier circuit. Graph 1773 in FIG. 17E shows the signal output from the light receiving element 204, amplified 25 times by the amplifier circuit 1733 without passing through the HPF 1732, and then acquired and visualized by the microcontroller 1700. In this example, although the signal value does not exceed the dynamic range, the heartbeat sound is not sufficiently amplified. Furthermore, the area marked with a dotted circle corresponds to the first heartbeat sound, but the heartbeat sound is buried in the hand shake component, making it impossible to accurately extract the heartbeat sound. Therefore, in this embodiment, components below 10 Hz are attenuated by the HPF 1732 before the signal is amplified by the amplifier circuit.

[0158] Graph 1775 in Figure 17F shows the frequency spectrum of the diaphragm displacement signal when hand shake and heartbeat sounds are present. Graph 1775 in Figure 17F shows the signal level according to frequency, obtained by performing a frequency analysis on the diaphragm displacement signal when the hand shake shown in Figure 17C is present. As shown in graph 1775, the signal level of the hand shake component peaks at a frequency of 5 kHz and rapidly decreases as the frequency increases from 5 kHz to 10 kHz. The signal level then gradually converges once the frequency exceeds 10 kHz. Therefore, the portion of the diaphragm displacement signal output from the light receiving element 204 with a frequency below 10 Hz can be attributed to hand shake. Therefore, by attenuating components below 10 Hz using the HPF 1732, the large amplitude caused by hand shake can be removed. If the HPF 1732 can effectively attenuate components below 10 Hz in the diaphragm displacement signal output from the light receiving element 204, the dynamic range will not be exceeded even if the signal is subsequently amplified with a large gain using an amplifier circuit.

[0159] The graphs in FIG. 17G show the frequency characteristics of the HPF 1732 when the capacitance value of the capacitor is varied. Graph 1776 shows the frequency characteristics when the capacitance value of the HPF 1732's capacitor is 0.47 μF and the cutoff frequency is 10 Hz. Graph 1777 shows the frequency characteristics when the capacitance value of the HPF 1732's capacitor is 0.22 μF and the cutoff frequency is 20 Hz. Graph 1778 shows the frequency characteristics when the capacitance value of the HPF 1732's capacitor is 0.1 μF and the cutoff frequency is 30 Hz. Experimental results showed that when the cutoff frequency was set in the range of 10 to 20 Hz, components below 10 Hz could be effectively attenuated. On the other hand, experimental results showed that when the cutoff frequency was set lower than 10 Hz, the high-pass filter was unable to effectively attenuate the hand-shake signal, resulting in hand-shake noise being output. On the other hand, if the cutoff frequency is set to a value greater than 20 Hz, for example, 30 Hz as in graph 1778, the heartbeat sound components are significantly attenuated, making it impossible to accurately extract the heartbeat sound.

[0160] Graph 1779 in FIG. 17H shows the waveform of the signal after processing by the diaphragm displacement signal processor 1730, i.e., the heartbeat signal. Specifically, graph 1779 in FIG. 17H shows the signal output from the light receiving element 204 processed by the HPF 1732, amplified 100 times by the amplifier circuits 1733 and 1734, and acquired and visualized by the microcontroller 1700. In this embodiment, the HPF 1732 effectively attenuates large-amplitude camera shake components. Therefore, as shown in FIG. 17H, it is possible to prevent the signal value amplified by the amplifier circuit from exceeding the dynamic range and resulting in peak cutting. Furthermore, in this embodiment, the HPF 1732 attenuates the camera shake component from the diaphragm displacement signal while minimizing attenuation of the heartbeat component. In this embodiment, after the camera shake component is attenuated by the HPF 1732, the small amplitude heartbeat sound component is amplified by 100 times by the amplifier circuits 1733 and 1734. Therefore, as shown in Fig. 17H, the first and second heartbeat sounds included in the heartbeat sound can be accurately extracted.

[0161] 17A, a buffer circuit 1731 is disposed on the signal path between the light receiving element 204 and the HPF 1732. By lowering the output impedance of the circuit elements preceding the HPF 1732 in this way, sufficient power is supplied to the capacitor of the HPF 1732, improving the output characteristics of the signal from the HPF 1732. This improves the quality of the heartbeat sound signal.

[0162] The amplifier circuit 1733 amplifies the signal received from the HPF 1732, attenuates high-frequency components (i.e., frequency components higher than a specific cutoff frequency), and passes low-frequency components (i.e., frequency components lower than the specific cutoff frequency). The amplifier circuit 1733 attenuates high-frequency noise contained in the diaphragm displacement signal and outputs the diaphragm displacement signal to the amplifier circuit 1734. The cutoff frequency of the amplifier circuit 1733 is 1 kHz in this embodiment. However, the cutoff frequency of the amplifier circuit 1733 may be 1 kHz or lower, for example, 950 Hz or 900 Hz. The cutoff frequency of the amplifier circuit 1733 may also be 1 kHz or higher and lower than 2 kHz. The operating power of the amplifier circuit 1733 is supplied from the voltage regulator 1716.

[0163] The amplifier circuit 1734 amplifies the signal received from the amplifier circuit 1734, attenuates high-frequency components of the signal, and outputs a signal that has passed low-frequency components to the microcontroller 1700. The cutoff frequency of the amplifier circuit 1734 may be the same as or different from the cutoff frequency of the amplifier circuit 1733. The operating power of the amplifier circuit 1734 is supplied from the voltage regulator 1716.

[0164] Both amplifier circuits 1733 and 1734 may be inverting amplifier circuits. In this case, by connecting the two amplifier circuits 1733 and 1734 in series, the polarity of the diaphragm displacement signal and the polarity of the heartbeat sound signal will match. Alternatively, diaphragm displacement signal processing unit 1730 may include only one amplifier circuit with a low-pass filter, and this amplifier circuit may be a non-inverting amplifier circuit. Furthermore, the polarity of the diaphragm displacement signal and the polarity of the heartbeat sound signal may be different from each other.

[0165] In this embodiment, the amplifier circuits 1733 and 1734 include low-pass filters, but the amplifier circuits 1733 and 1734 may not include low-pass filters. In this case, another low-pass filter may be disposed on the signal path between the HPF 1732 and the microcontroller 1700. Furthermore, a band-pass filter may be disposed on this signal path instead of the low-pass filter.

[0166] The diaphragm displacement signal processing unit 1730 has an amplifier circuit on the signal path between the HPF 1732 and the microcontroller 1700, and further on the signal path between the light receiving element 204 and the microcontroller 1700, and the amplifier circuit amplifies the heartbeat sound signal. Note that in this embodiment, a configuration in which the diaphragm displacement signal processing unit 1730 has an amplifier circuit will be described as an example, but a configuration in which the microcontroller 1700 has an amplifier circuit may also be used.

[0167] As shown in FIG. 17A , the diaphragm displacement signal processing unit 1730 further outputs the diaphragm displacement signal, before being processed by the HPF 1732, to the microcontroller 1700. In the example of FIG. 17A , a node 1735 located on the signal path between the buffer circuit 1731 and the HPF 1732 is connected to the microcontroller 1700. The diaphragm displacement signal is output from this node 1735 to the microcontroller 1700. As will be described later, the microcontroller 1700 detects the pressing state (also referred to as the contact state) of the diaphragm 206 based on this diaphragm displacement signal and performs a volume setting operation, which will be described later. The diaphragm displacement signal to the microcontroller 1700 may be output from another node on the signal path between the light receiving element 204 and the HPF 1732. For example, the diaphragm displacement signal to the microcontroller 1700 may be output from a node on the signal path between the light receiving element 204 and the buffer circuit 1731.

[0168] The microphone signal processing unit 1740 processes the microphone signal to generate a sound signal representing sound transmitted from the surface of the living body to the diaphragm 206, and outputs this sound signal to the microcontroller 1700. Specifically, the microphone signal processing unit 1740 generates the sound signal by extracting components of a specific frequency band contained in the microphone signal. As described above, the microphone signal is a signal generated by the microphone 1101 based on air vibrations generated in the internal space 213 (see FIG. 2A, etc.; this may be an enclosed space) facing the inner surface 206b of the diaphragm 206. The microphone signal is also called a vibration signal. The sound signal generated by the microphone signal processing unit 1740 based on the microphone signal is output in the respiratory sound mode, and therefore will be referred to as a respiratory sound signal in the following description. Because the microphone signal also represents sound transmitted from the surface of the living body to the diaphragm 206, the microphone signal is a type of respiratory sound signal.

[0169] The microphone signal processing unit 1740 includes an amplifier circuit 1741 with a low-pass filter on the signal path between the microphone 1101 and the microcontroller 1700. The microphone signal processing unit 1740 receives a microphone signal from the microphone 1101 and outputs a respiratory sound signal to the microcontroller 1700.

[0170] The amplifier circuit 1741 amplifies the signal received from the microphone 1101 and attenuates the high-frequency components to output the resulting signal to the microcontroller 1700. In this way, the amplifier circuit 1741 appropriately removes high-frequency noise contained in the microphone signal. The cutoff frequency of the amplifier circuit 1741 may be, for example, 1 kHz or less, and may be, for example, 1 kHz, 950 Hz, or 900 Hz. The operating power of the amplifier circuit 1741 may be supplied from the voltage regulator 1716.

[0171] Low-frequency noise contained in the microphone signal is smaller than low-frequency noise contained in the diaphragm displacement signal. Therefore, in this embodiment, the microphone signal processing unit 1740 does not include an HPF on the signal path between the microphone 1101 and the microcontroller 1700. In this case, the signal path between the microphone 1101 and the microcontroller 1700 passes components below the cutoff frequency of the amplifier circuit 1741. However, an HPF may be disposed on the signal path between the microphone 1101 and the amplifier circuit 1741. In this case, the cutoff frequency of the HPF disposed on the signal path between the microphone 1101 and the amplifier circuit 1741 is set lower than the cutoff frequency of the HPF 1732 (e.g., 5 Hz, 3 Hz, etc.). Alternatively, the amplifier circuit 1741 may be omitted, and the microphone signal may be output directly from the microphone 1101 to the microcontroller 1700 as a respiratory sound signal. The microcontroller 1700 may amplify this respiratory sound signal.

[0172] In the example of FIG. 17A, other circuit elements may be disposed on the signal path between the buffer circuit 1731 and the light receiving element 204.

[0173] The diaphragm displacement signal, heartbeat sound signal, respiratory sound signal, and acceleration signal are supplied to corresponding input terminals of the microcontroller 1700. The microcontroller 1700 includes an A / D converter 611 that converts these analog signals into digital signals, and processing by the microcontroller 1700 is performed using the digital signals.

[0174] [Functional Block Configuration of the Electronic Auscultation Device in the Second Embodiment] The functional blocks realized by the processor 1701 of the microcontroller 1700 will be described with reference to Fig. 18. Each functional block in Fig. 18 is realized by loading a program stored in the nonvolatile memory 1702 into the RAM 1704 and executing it with the processor 1701. However, some or all of the functional blocks in Fig. 18 may be realized by a dedicated integrated circuit such as an application specific integrated circuit (ASIC).

[0175] The motion detection unit 1801 detects the motion of the electronic auscultation device 1000 based on the acceleration signal acquired from the acceleration sensor 1750. For example, the motion detection unit 1801 determines that the electronic auscultation device 1000 is moving when the acceleration in at least one of the three axial directions, the x-axis, the y-axis, and the z-axis, is non-zero or exceeds a threshold. Conversely, the motion detection unit 1801 determines that the electronic auscultation device 1000 is stationary when the acceleration in all axial directions is zero or less than a threshold.

[0176] The display control unit 1802 controls the display of the display unit 122. The input acquisition unit 1803 acquires user input using the operation unit 123 and the power switch 124. The power management unit 1804 controls the operation of the power supply unit 1710, for example, to generate a specific voltage. Specifically, the power management unit 1804 switches the level of a control signal supplied to the load switch 1715, switching the load switch 1715 on and off. As described above, when the load switch 1715 is turned off, the voltage V0 is no longer supplied to the voltage regulator 1716, so that the power supply from the voltage regulator 1716 is stopped and the system transitions to a power saving mode 2601, which will be described later.

[0177] The pressure detection unit 1805 detects that the diaphragm 206 is pressed or contacted based on the diaphragm displacement signal acquired from the diaphragm displacement signal processing unit 1730. Hereinafter, the pressure state of the diaphragm 206 will be simply referred to as the "pressure state." For example, the pressure detection unit 1805 can identify which of a plurality of states the pressure state is in. Specifically, the pressure detection unit 1805 identifies whether the pressure state is in use (first state) or non-use (second state). The non-use state (second state) refers to a pressure state in which the user does not press the diaphragm 206 against the surface of the living body. The use state (first state) refers to a pressure state in which the user presses the diaphragm 206 against the surface of the living body. The displacement amount of the diaphragm 206 in the non-use state is smaller than the displacement amount of the diaphragm 206 in the use state. Therefore, the pressure detection unit 1805 determines that the pressed state is the unused state when the displacement amount of the diaphragm 206 specified from the diaphragm displacement signal is less than a threshold value, whereas the pressure detection unit 1805 determines that the pressed state is the used state when the displacement amount of the diaphragm 206 exceeds the threshold value.

[0178] The use state is further classified into two states: a proper state and an overpressure state. In this case, the pressure detection unit 1805 determines whether the pressure state is one of three states: a proper state (first state), a non-use state (second state), and an overpressure state (third state). The overpressure state (third state) is a pressure state in which the pressure of the diaphragm 206 against the biological surface is too strong, preventing sound from being properly transmitted from the biological surface to the diaphragm 206. The proper state is a pressure state in which sound is properly transmitted from the biological surface to the diaphragm 206. The displacement of the diaphragm 206 in the overpressure state is greater than the displacement of the diaphragm 206 in the proper state. The pressure detection unit 1805 determines that the pressure state is a non-use state when the displacement of the diaphragm 206 is less than a threshold value. On the other hand, the pressure detection unit 1805 determines that the pressure state is appropriate when the displacement amount of the diaphragm 206 exceeds the threshold value and is less than another threshold value that is greater than the threshold value.The pressure detection unit 1805 then determines that the pressure state is an overpressure state when the displacement amount of the diaphragm 206 exceeds this other threshold value.

[0179] The output control unit 1806 transmits the heartbeat sound signal acquired from the diaphragm displacement signal processing unit 1730 and the respiratory sound signal acquired from the microphone signal processing unit 1740 to an external device such as the computer 630 or the sound output device 620 via the wireless communication unit 614 or the wired communication unit 617. The output selection unit 1807 selects the sound signal (heartbeat sound signal, respiratory sound signal, or both) to be output by the output control unit 1806. The output selection unit 1807 selects the sound signal to be output based on the user input acquired by the input acquisition unit 1803.

[0180] The output control unit 1806 performs signal processing on the sound signal before outputting it. Specifically, the output control unit 1806 includes a reduction processing unit 1811 and a smoothing processing unit 1812. The reduction processing unit 1811 performs reduction processing to compare the amplitude of the sound signal with a threshold amplitude and reduce amplitude that exceeds the threshold amplitude. The smoothing processing unit 1812 performs smoothing processing to remove components above a cutoff frequency (i.e., high-frequency components) from the sound signal after reduction processing. Details of the reduction processing and smoothing processing will be described later.

[0181] The detection control unit 1808 controls the operations of the displacement detection unit 1011, which includes the light emitting element 202 and the light receiving element 204, and the vibration detection unit 1012, which includes the microphone 1101. For example, if the displacement detection unit 1011 and the vibration detection unit 1012 have adjustable parameters, the detection control unit 1808 adjusts these parameters.

[0182] The volume adjustment unit 1809 adjusts the volume of the sound signal (heartbeat sound signal or breathing 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 adjustment unit 1809 adjusts the volume based on a user input acquired by the input acquisition unit 1803. For example, the volume adjustment unit 1809 increases the volume when the user operates the volume up button 123a included in the operation unit 123 in FIG. 1A to instruct the user to increase the volume. The volume adjustment unit 1809 decreases the volume when the user operates the volume down button 123b included in the operation unit 123 in FIG. 1A to instruct the user to decrease the volume.

[0183] The volume adjustment unit 1809 also adjusts the volume based on the pressing state. For example, the volume adjustment unit 1809 can set the volume to a normal level when the diaphragm 206 is pressed by the object to be measured by a certain amount or more (i.e., when it is determined that the object is in use). The operation of setting the volume based on the pressing state will be described later. The normal level volume is a volume that is suitable for listening to the sound signal reproduced by the sound output device 620. The volume adjustment unit 1809 adjusts the value of the normal level based on the user input acquired by the input acquisition unit 1803.

[0184] The volume adjustment unit 1809 sets the volume to the mute level when the diaphragm 206 is not being pressed by the device under test (when the device is determined to be in an unused state). The mute level volume means zero or a volume lower than the normal level volume. For example, the mute level volume may be so low that the sound signal reproduced by the sound output device 620 is inaudible. The mute level can also be a constant multiple (e.g., 10%) of the normal level. In this configuration where the mute level is dependent on the normal level, if the normal level is changed by user input, for example, via a volume adjustment button included in the operation unit 123, the mute level also changes depending on the normal level. On the other hand, the mute level can also be set independently of the normal level. If the mute level is independent of the normal level, the mute level does not change even if the normal level is changed, for example, by user input.

[0185] The volume adjustment unit 1809 sets the volume to a normal level when the diaphragm 206 is pressed by the object to be measured with a certain pressure or more (i.e., when it is determined that the device is in use). The normal level is set according to a user input via a volume adjustment button included in the operation unit 123. On the other hand, when the diaphragm 206 is pressed by the object to be measured with a pressure greater than necessary (i.e., when it is determined that the pressure state is an overpressure state), the volume adjustment unit 1809 sets the volume to a mute level. However, when the pressure state is an overpressure state, it is not necessarily necessary to set the volume to a mute level, and the volume adjustment unit 1809 may set the volume to a normal level in the same way as when the pressure state is appropriate.

[0186] The volume adjustment unit 1809 adjusts the gain of at least one of the amplifier circuits 1733 and 1734 to adjust the volume level of the heartbeat sound signal. Alternatively, the volume adjustment unit 1809 may adjust the digital value of the sound signal that the output control unit 1806 outputs to the outside to adjust the volume level of the heartbeat sound signal. The volume adjustment unit 1809 adjusts the gain of the amplifier circuit 1741 to adjust the volume level of the breath sound signal. Alternatively, the volume adjustment unit 1809 may adjust the digital value of the sound signal that the output control unit 1806 outputs to the outside to adjust the volume level of the breath sound signal.

[0187] [Volume Setting Operation 1 of the Electronic Auscultation Device in the Second Embodiment] The volume setting operation of the electronic auscultation device 1000 will be described with reference to FIG. 19A . FIG. 19A is a flowchart illustrating the process of determining whether the pressing state is in one of two states, a non-use state or a use state. Each step of the method of FIG. 19A is implemented by the processor 1701 executing a program stored in the non-volatile memory 1702. However, some or all of the steps of the method of FIG. 19A may be implemented by a dedicated integrated circuit. The processor 1701 starts the method of FIG. 19A in response to the power-on of the electronic auscultation device 1000 and ends the method of FIG. 19A in response to the power-off of the electronic auscultation device 1000. Note that in this embodiment, when the power of the electronic auscultation device 1000 is turned off, the processor 1701 stores the volume setting value at the normal level in the non-volatile memory 1702. When the power of the electronic auscultation device 10000 is turned on, the processor 1701 reads the normal volume setting value stored in the nonvolatile memory 1702 and sets it as the initial normal volume value. In this embodiment, the volume is set to the mute level at the start of the flowchart in Fig. 19A, but it may also be set to the initial normal volume value.

[0188] In S1901, the processor 1701 (e.g., the pressure detection unit 1805) acquires a diaphragm displacement signal from the diaphragm displacement signal processing unit 1730. Since the diaphragm displacement signal is output from the node 1735 (see FIG. 17A ) of the diaphragm displacement signal processing unit 1730 while the power of the electronic auscultation device 1000 is on, the processor 1701 acquires this diaphragm displacement signal.

[0189] In S1902, the processor 1701 (e.g., the pressure detection unit 1805) determines whether the pressure state is the unused state. If the processor 1701 determines that the pressure state is the unused state (YES in S1902), the process proceeds to S1904, and otherwise (NO in S1902), the process proceeds to S1903. In the method of Fig. 19A, determining that the pressure state is not the unused state means that the pressure state is determined to be the used state.

[0190] In S1903, the processor 1701 (volume adjustment unit 1809) sets the volume to the normal level. Specifically, if the current volume is at the normal level, the processor 1701 maintains the current volume, and if the current volume is at the mute level, the processor 1701 switches the volume to the normal level. The normal level volume setting is stored in the nonvolatile memory 1702 when the electronic auscultation device 1000 is powered off, and when the power is turned on, the setting is read as the initial value of the normal level. Therefore, if the volume adjustment button included in the operation unit 123 is not operated by the user, the initial value is set to the normal level volume. On the other hand, if the volume adjustment button is operated by the user, the normal level volume is updated, and the updated volume is stored in the nonvolatile memory 1702 as the normal level volume. In addition to the above, in S1903, the processor 1701 notifies the user that the pressed state is in use and that the volume is at the normal level. In this embodiment, the output control unit 1806 issues the above notification by voice via the wireless communication unit 614 or the wired communication unit 617, and the display control unit 1802 issues the above notification by turning on an LED included in the display unit 122. However, the notification method is not limited to this, and either voice or LED lighting may be used, or the above notification may be issued by vibrating the electronic auscultation device 1000, for example.

[0191] In S1904, the processor 1701 (e.g., the volume adjustment unit 1809) sets the volume to the mute level. That is, if the current volume is at the mute level, the processor 1701 maintains the current volume, and if the current volume is at the normal level, the processor 1701 switches the volume to the mute level. In addition, the processor 1701 notifies the user that the pressed state is an unused state and that the volume is at the mute level. For example, the output control unit 1806 may issue the notification via the wireless communication unit 614 or the wired communication unit 617, or the display control unit 1802 may issue the notification by turning on an LED included in the display unit 122.

[0192] The processor 1701 repeats steps S1901 to S1904. In this embodiment, the processor 1701 repeats steps S1901 to S1904 at a predetermined interval (e.g., every 1 ms to 100 ms). According to the method of FIG. 19A , if the pressure state is in use, the volume level is set to the normal level, and if the pressure state is in non-use, the volume level is set to the mute level. According to the above embodiment, the electronic auscultation device automatically sets the volume according to the pressure state of the diaphragm. Specifically, the electronic auscultation device determines whether the living body is in contact with the diaphragm (pressure of a predetermined level or more) based on whether the diaphragm displacement amount determined from the diaphragm displacement signal exceeds or is less than a threshold, and automatically adjusts the volume according to the determination result. Therefore, the user can contact the electronic auscultation device with the living body and output audio only when auscultation is desired. Furthermore, the sliding noise and contact noise when contacting the living body can be suppressed, enabling noiseless auscultation.

[0193] [Audible Signal Output Operation of Electronic Auscultation Device in Second Embodiment] The acoustic signal output operation of the electronic auscultation device 1000 will be described with reference to Fig. 19B. Each step of the method in Fig. 19B is executed by, for example, the processor 1701. However, some or all of the steps of the method in Fig. 19B may be realized by a dedicated integrated circuit. The processor 1701 starts the method in Fig. 19B in response to the electronic auscultation device 1000 being powered on or returning from the power saving mode 2601. The processor 1701 ends the method in Fig. 19B in response to the electronic auscultation device 1000 being powered off or transitioning to the power saving mode 2601.

[0194] In S1911, the processor 1701 (e.g., the output control unit 1806) A / D converts the heartbeat sound signal or the respiratory sound signal supplied to the input terminal. Whether the heartbeat sound signal or the respiratory sound signal is A / D converted is determined depending on the operation mode of the electronic auscultation device 1000. Specifically, when the electronic auscultation device 1000 is in a heartbeat sound mode, which is an example of an auscultation mode, the processor 1701 A / D converts the heartbeat sound signal. When the electronic auscultation device 1000 is in a respiratory sound mode, which is an example of an auscultation mode, the processor 1701 A / D converts the respiratory sound signal. The A / D converted sound signal is output from the electronic auscultation device 1000. In the following description of FIG. 19B , the sound signal to be output is simply referred to as the sound signal. In S1911, the processor 1701 may A / D convert both the heartbeat sound signal and the respiratory sound signal, or may perform subsequent processing on only the sound signal to be output.

[0195] The processor 1701 repeats the following steps S1911 to S1913 at a predetermined sampling rate (e.g., 2 ms). The numerical value corresponding to the time when S1911 starts in each trial of this repetition is represented as sampling time t. The sound signal after A / D conversion (i.e., a digital sound signal) is represented as X. The signal value of the sound signal X at sampling time t is represented as X(t). The processor 1701 quantizes the voltage (i.e., an analog sound signal) supplied to the input terminal into, for example, a 12-bit signal value. For subsequent processing, the processor 1701 stores the sound signal X in RAM 1704.

[0196] In S1912, the processor 1701 (e.g., the output control unit 1806) performs signal processing on the sound signal X. Specifically, first, the processor 1701 (e.g., the reduction processing unit 1811) performs reduction processing on the sound signal X to generate a sound signal Y. The sound signal Y is a signal in which the amplitude of the sound signal X that exceeds an amplitude threshold has been reduced. The signal value of the sound signal Y at sampling time t is represented as Y(t). For subsequent processing, the processor 1701 stores the sound signal Y in the RAM 1704.

[0197] The processor 1701 performs the reduction process according to the following equation 9: (Equation 9)

[0198] In Equation 9, the baseline value B is a value representing the baseline of an analog sound signal. The amplitude of the sound signal X is given by the difference between the signal value X(t) of the sound signal X and the baseline value B, i.e., |X(t)-B|. The baseline value B is set in advance and stored in the nonvolatile memory 1702. When the sound signal is quantized at 12 bits, for example, B=2047.

[0199] In Equation 9, amplitude threshold C represents the amplitude threshold used in the reduction process. Processor 1701 compares the amplitude of sound signal X with amplitude threshold C and determines Y(t) based on the comparison result. When the amplitude of sound signal X is equal to or less than amplitude threshold C, processor 1701 sets the signal value X(t) of sound signal X as the signal value Y(t) of sound signal Y. The amplitude threshold C is set in advance and stored in non-volatile memory 1702. When the sound signal is quantized at 12 bits, C=1024, for example.

[0200] When the amplitude of the sound signal X is greater than the amplitude threshold C, the processor 1701 sets the value obtained by reducing the amplitude of the sound signal X as the amplitude of the sound signal Y. Specifically, the processor 1701 sets the amplitude of the sound signal Y as the sum of the difference between the amplitude of the sound signal X and the amplitude threshold C, i.e., |X(t)-B|-C multiplied by the reduction factor k, and the amplitude threshold C. The reduction factor k is a real number greater than or equal to 0 and less than 1, which is set in advance and stored in the non-volatile memory 1702. The closer the reduction factor k is to 0, the greater the amplitude of the sound signal X is reduced. When k=0, the amplitude of the sound signal X matches the amplitude threshold C. In other words, the sound signal X is clipped at the amplitude threshold C.

[0201] In general, sound signal X may include noise components having larger amplitudes than body sounds. By performing the above-described reduction processing on sound signal X, it is possible to reduce the amplitudes of noise components having large amplitudes while maintaining the amplitudes of body sounds.

[0202] Next, the processor 1701 (e.g., the smoothing processing unit 1812) performs smoothing processing on the sound signal Y after the reduction processing, thereby generating a sound signal Z. The sound signal Z is a signal that has been smoothed by removing high-frequency components equal to or higher than the cutoff frequency from the sound signal Y. The signal value of the sound signal Z at the sampling time t is represented as Z(t). The processor 1701 stores the sound signal Z in the RAM 1704 for subsequent processing.

[0203] The processor 1701 performs the smoothing process according to the following equation 10: (Equation 10)

[0204] In Equation 10, the sampling rate r is the sampling rate of A / D conversion. The number of terms N is the number of signal values ​​of the sound signal Y used for the moving average. The number of terms N is set in advance and stored in the non-volatile memory 1702. For example, N = 32. By taking the moving average in this manner, high-frequency components equal to or higher than the cutoff frequency determined by the sampling rate and the number of terms N are removed from the sound signal Y. This reduces the amount of change in the slope of the sound signal Z before and after the amplitude threshold C compared to the sound signal Y, thereby reducing noise that is unpleasant to the user.

[0205] In S1913, the processor 1701 (for example, the output control unit 1806) outputs the sound signal Z. The sound signal Z is output in accordance with the volume determined in the operation of FIG. 19A.

[0206] In the above-described processing, the processor 1701 generates a sound signal Z by performing both a reduction process and a smoothing process on the sound signal X, and outputs this sound signal Z. Alternatively, the processor 1701 may perform a reduction process on the sound signal X without performing a smoothing process. In this case, the processor 1701 may output a sound signal Y. If the value of the reduction factor k is large, the amount of change in the slope of the sound signal Y before and after the amplitude threshold C is small, and therefore, even if the sound signal Y is output, there is little noise that the user finds unpleasant.

[0207] In the above example, the processor 1701 constantly performs the reduction and smoothing processes while the sound signal is being output. That is, the processor 1701 performs the reduction and smoothing processes not only while the pressing state is determined to be the in-use state, but also during other periods. Alternatively, the processor 1701 may perform the reduction and smoothing processes only during a portion of the period during which the sound signal is being output. When the reduction and smoothing processes are not performed, the processor 1701 outputs a sound signal X that has not undergone signal processing. In the electronic auscultation device 1000, large-amplitude noise is likely to occur when the pressing state changes from the in-use state to the in-use state or from the in-use state to the in-use state. In particular, immediately after it is determined that the pressing state has changed from the in-use state to the in-use state, the volume is in the process of transitioning from the normal level to the mute level, and the user may experience high-volume noise. Therefore, after it is determined that the pressing state has changed from the in-use state to the out-of-use state, processor 1701 performs the reduction process and smoothing process until a predetermined condition is satisfied, and does not need to perform the reduction process and smoothing process during other periods. This makes it possible to prevent high-volume noise from reaching the user.

[0208] The specified condition for terminating the reduction process and the smoothing process may be that the volume has finished transitioning to the mute level, that a specified time has elapsed since it was determined that the pressing state has changed from a use state to a non-use state, that it has been determined that the pressing state has changed from a non-use state back to a use state, or a combination of these.

[0209] The processor 1701 may always perform the smoothing process while the sound signal is being output, and may perform the reduction process only during a certain period while the sound signal is being output. For example, after it is determined that the pressing state has changed from the use state to the non-use state, the processor 1701 may perform the reduction process until a predetermined condition is met, and may not perform the reduction process during other periods. The predetermined condition is the same as described above.

[0210] The processor 1701 may switch whether to perform the reduction process and the smoothing process for each mode. For example, the processor 1701 performs both the reduction process and the smoothing process in the heartbeat sound mode. As described above, the period during which the reduction process and the smoothing process are performed in the heartbeat sound mode may be the entire period during which the sound signal is output, or only a portion of that period. The processor 1701 performs the smoothing process but not the reduction process in the breath sound mode. As described above, the period during which the smoothing process is performed in the breath sound mode may be the entire period during which the sound signal is output, or only a portion of that period.

[0211] The processor 1701 may switch the cutoff frequency of the smoothing process for each mode. For example, the processor 1701 sets the number of terms N to 32 in the heartbeat sound mode and sets the number of terms N to 16 in the breath sound mode. This makes the cutoff frequency of the smoothing process in the breath sound mode higher than the cutoff frequency of the smoothing process in the heartbeat sound mode. In the breath sound mode, the frequency of the biological sounds of the observation target is higher than in the heartbeat sound mode. Therefore, by increasing the cutoff frequency of the smoothing process in the breath sound mode, the risk of biological sounds being filtered out can be reduced.

[0212] In the above-described operation, a fixed value is used as the amplitude threshold C. Alternatively, the processor 1701 may determine the amplitude threshold C while the sound signal is being output and perform the reduction process using the determined amplitude threshold C. For example, the processor 1701 may determine the amplitude threshold C based on the amplitude of the sound signal X that has not been subjected to the reduction process while the pressed state is determined to be the in-use state. For example, the processor 1701 may determine the amplitude threshold C based on the maximum value of the amplitude of the sound signal X that has not been subjected to the reduction process while the pressed state is determined to be the in-use state. Specifically, if the maximum value of the amplitude is greater than a default value for the amplitude threshold C, the processor 1701 may use this maximum value as the amplitude threshold C. If the value obtained by adding or multiplying this maximum amplitude by a predetermined value is greater than the default value, the processor 1701 may use this value as the amplitude threshold C. The processor 1701 may use another representative value, for example, the average value of the peak amplitude, instead of the maximum value of the amplitude of the sound signal X. It is considered that large amplitude noise is unlikely to occur in the sound signal X while the pressed state is determined to be the in-use state. Therefore, by determining the amplitude threshold C based on the amplitude of the sound signal X during this period, the amplitude of only the noise can be reduced.

[0213] After determining that the pressing state has changed from the in-use state to the unused state, processor 1701 may reset the amplitude threshold C determined as described above to a default value based on whether a predetermined condition is satisfied. The predetermined condition for resetting the amplitude threshold C may be that the volume has finished transitioning to the mute level, that a predetermined time has elapsed since it was determined that the pressing state has changed from the in-use state to the unused state, that the pressing state has changed again from the unused state to the in-use state, or a combination of these.

[0214] [Specific Example 1 of Changes in Volume and Amplitude of the Electronic Auscultation Device in the Second Embodiment] A specific example of changes in volume and amplitude using the method of Figures 19A and 19B will be described with reference to Figure 20. Graph 2001 shows the change over time of the diaphragm displacement signal supplied to the microcontroller 1700. Graph 2002 shows the change over time of the heartbeat sound signal supplied to the microcontroller 1700. Graph 2003 shows the change over time of the volume. Graph 2004 shows the change over time of the sound signal X. Graph 2005 shows the change over time of the sound signal Z.

[0215] The reference voltage Vfl indicates the value of the diaphragm displacement signal when the diaphragm 206 is not in contact with the surface of a living body, i.e., when it is flat. The reference voltage Vfl is determined when the electronic auscultation device 1000 is manufactured and stored in the non-volatile memory 1702. The threshold voltage Th1 indicates the value of the diaphragm displacement signal at the boundary between the unused state and the used state. Like the reference voltage Vfl, the threshold voltage Th1 is also determined when the electronic auscultation device 1000 is manufactured and stored in the non-volatile memory 1702.

[0216] The pressure detection unit 1805 determines that the pressed state is the unused state when the value of the diaphragm displacement signal is greater than the threshold voltage Th1. On the other hand, the pressure detection unit 1805 determines that the pressed state is the used state when the value of the diaphragm displacement signal is less than the threshold voltage Th1. The pressure detection unit 1805 may determine either state when the value of the diaphragm displacement signal is equal to the threshold voltage Th1. Instead of comparing the value of the diaphragm displacement signal with the threshold voltage Th1, the pressure detection unit 1805 may compare the difference between the reference voltage Vfl and the value of the diaphragm displacement signal with a threshold. For example, the pressure detection unit 1805 may determine that the pressed state is the unused state when the difference between the voltage Vfl and the value of the diaphragm displacement signal is smaller than the threshold. The pressure detection unit 1805 may determine that the pressed state is the used state when the difference between the voltage Vfl and the value of the diaphragm displacement signal is greater than the threshold. In addition, the pressure detection unit 1805 may count the number of times the value of the diaphragm displacement signal falls below the threshold voltage Th1, and if that number exceeds a predetermined number within a certain period of time, determine that the pressure state is in use.

[0217] At time t0, the diaphragm 206 is in an unpressured state, i.e., in a flat state. Therefore, the value of the diaphragm displacement signal is equal to the reference voltage Vfl. Therefore, the pressure detection unit 1805 determines that the pressed state is an unused state. As a result, the volume adjustment unit 1809 sets the volume to the mute level. Between times t0 and t1, the value of the diaphragm displacement signal is greater than the threshold voltage Th1. Therefore, the volume adjustment unit 1809 maintains the volume at the mute level.

[0218] At time t1, the value of the diaphragm displacement signal falls below the threshold voltage Th1. In response, the pressure detection unit 1805 determines that the pressure state has changed from the unused state to the used state. Therefore, the volume adjustment unit 1809 switches the volume from the mute level to the normal level. However, if the volume is suddenly switched from the mute level to the normal level, it may cause discomfort to the user. Therefore, in this embodiment, the volume adjustment unit 1809 changes the volume from the mute level to the normal level over a time period L1. In other words, the time period L1 is the time required to reduce the volume from the mute level to the normal level. The time period L1 is preferably, for example, 100 ms to 500 ms. The volume change may be linear or nonlinear.

[0219] Between times t1 and t3, the value of the diaphragm displacement signal is smaller than threshold voltage Th1, so after volume adjustment unit 1809 has finished setting the volume to the normal level at time t2, it maintains the volume at the normal level.

[0220] At time t3, the value of the diaphragm displacement signal exceeds the threshold voltage Th1. In response, the pressure detection unit 1805 determines that the pressure state has changed from the in-use state to the unused state. In this embodiment, if the value of the diaphragm displacement signal exceeds the threshold voltage Th1 even once, it is determined that the pressure state has changed from the in-use state to the unused state. However, taking into account the influence of momentary noise, it may also be determined that the pressure state has changed from the in-use state to the unused state when the value of the diaphragm displacement signal exceeds the threshold voltage Th1 a predetermined number of times within a certain period of time. When the pressure detection unit 1805 determines that the pressure state has changed from the in-use state to the unused state, the volume adjustment unit 1809 switches the volume from the normal level to the mute level. When switching the volume from the normal level to the mute level, it is preferable to switch to the mute level in a short time, unlike when switching the volume from the mute level to the normal level. This is because, during the process of changing the pressure state of the diaphragm 206 from the inactive state, vibrations of the diaphragm 206 due to the rustling of the patient's clothes, etc., may be extracted as a heartbeat sound signal, and if this is output as audio, it may produce an unpleasant sound. Therefore, the volume adjustment unit 1809 changes the volume from the mute level to the normal level over a time period L2 that is shorter than the time period L1. In other words, the time period L2 is the time required to increase the volume from the normal level to the mute level. The time period L2 may be, for example, 10 ms to 100 ms. The change in volume may be linear or nonlinear.

[0221] After time t4, the value of the diaphragm displacement signal is greater than the threshold voltage Th1, so the volume adjuster 1809 maintains the volume at the mute level after the volume has been switched to the mute level.

[0222] When the pressing state is the unused state, the sound signal does not contain biological components and is entirely noise. Therefore, the user of the electronic auscultation device 1000 does not need such sound signals. In particular, just before time t1, the user moves the electronic auscultation device 1000 to bring the diaphragm 206 into close contact with the surface of the living body. As shown in graph 2002, this user action can cause the heartbeat sound signal to contain loud noise. Therefore, when the pressing state is the unused state, the electronic auscultation device 1000 mute the volume to prevent the user from hearing the noise.

[0223] Between times t1 and t2, the volume adjustment unit 1809 gradually increases the volume from the mute level to the normal level over a relatively long period of time L1. This prevents the user from being confused by a sudden increase in volume. On the other hand, between times t3 and t4, the volume adjustment unit 1809 decreases the volume from the normal level to the mute level over a relatively short period of time L2. This allows the user to quickly transition to a mute state, freeing them from noise.

[0224] The processor 1701 outputs a sound signal Z. The processor 1701 does not perform reduction processing and smoothing processing during periods other than the time t3 to t4. Therefore, the signal value of the sound signal Z is equal to the signal value of the sound signal X. The processor 1701 performs reduction processing and smoothing processing during the period from the time t3 to t4. Therefore, the amplitude of the sound signal Z becomes a value obtained by reducing the amplitude of the sound signal X.

[0225] [Volume Setting Operation 2 of the Electronic Auscultation Device in the Second Embodiment] Another volume setting operation by the electronic auscultation device 1000 will be described with reference to Fig. 21. Differences from the method in Fig. 19A will be described below. In the method in Fig. 21, the pressure detection unit 1805 identifies which of three pressure states the pressure state is: a non-use state, a proper state, or an overpressure state.

[0226] In S1902, if the processor 1701 (e.g., the pressure detection unit 1805) determines that the pressure state is not the unused state ("NO" in S1902), the processor 1701 (e.g., the pressure detection unit 1805) transitions the process to S2101. In S2101, the processor 1701 (e.g., the pressure detection unit 1805) determines whether the pressure state is the overpressure state. If the processor 1701 determines that the pressure state is the overpressure state ("YES" in S2101), the processor 1701 transitions the process to S2102, and otherwise ("NO" in S2101), the processor 1701 transitions the process to S1903. In the method of FIG. 21 , determining that the pressure state is neither the unused state nor the overpressure state means that the pressure state is determined to be the appropriate state.

[0227] In S2102, the processor 1701 (e.g., the volume adjustment unit 1809) sets the volume to the mute level. That is, if the current volume is at the mute level, the processor 1701 maintains the current volume, and if the current volume is at the normal level, the processor 1701 switches the volume to the mute level. In addition, the processor 1701 notifies the user of information regarding the pressure state of the diaphragm 206 and that the volume is at the mute level. The information regarding the pressure state of the diaphragm 206 includes whether the pressure state is an overpressure state or an unused pressure state. For example, the output control unit 1806 may issue the notification via the wireless communication unit 614 or the wired communication unit 617, or the display control unit 1802 may issue the notification by turning on an LED included in the display unit 122. Also, in the method of FIG. 21, in steps S1903 and S1904, the processor 1701 (e.g., the output control unit 1806) notifies the user of information regarding the pressure state of the diaphragm 206 (e.g., that the pressure state is not an overpressure state).

[0228] In the present embodiment, the processor 1701 (for example, the volume adjustment unit 1809) sets the volume to a mute level in S2102, but may instead set the volume to a normal level, for example.

[0229] According to the method of Fig. 21, if the pressure state is the proper state, the volume level is set to the normal level. If the pressure state is the unused state or the excessive pressure state, the volume level is set to the mute level. The method of setting the volume when the pressure state is the proper state or the unused state is the same as that of Fig. 19A.

[0230] [Specific Example 2 of Volume Changes in the Electronic Auscultation Device in the Second Embodiment] A specific example of volume changes using the method in Fig. 21 will be described with reference to Fig. 22. Graph 2201 shows the time change in the diaphragm displacement signal supplied to the microcontroller 1700. Graph 2202 shows the time change in the heartbeat sound signal supplied to the microcontroller 1700. Graph 2203 shows the time change in volume.

[0231] The reference voltage Vfl indicates the value of the diaphragm displacement signal when the diaphragm 206 is not pressed (flat). The reference voltage Vfl may be determined by testing during manufacturing of the electronic auscultation device 1000 and stored in the non-volatile memory 1702. The threshold voltage Th1 indicates the value of the diaphragm displacement signal at the boundary between an unused state and a proper state. The threshold voltage Th1 may be determined during manufacturing of the electronic auscultation device 1000 and stored in the non-volatile memory 1702. The threshold voltage Th2 indicates the value of the diaphragm displacement signal at the boundary between a proper state and an overpressure state. The threshold voltage Th2 may be determined during manufacturing of the electronic auscultation device 1000 and stored in the non-volatile memory 1702.

[0232] The pressure detection unit 1805 may determine that the pressure state is the unused state when the value of the diaphragm displacement signal is greater than the threshold voltage Th1. The pressure detection unit 1805 may determine that the pressure state is the appropriate state when the value of the diaphragm displacement signal is smaller than the threshold voltage Th1 and greater than the threshold voltage Th2. The pressure detection unit 1805 may determine that the pressure state is the overpressure state when the value of the diaphragm displacement signal is smaller than the threshold voltage Th2. When the value of the diaphragm displacement signal is on the boundary, the pressure detection unit 1805 may determine that the value is on either side of the boundary. As in the description of FIG. 20 , instead of comparing the value of the diaphragm displacement signal with the threshold voltages Th1 and Th2, the pressure detection unit 1805 may compare the difference between the reference voltage Vfl and the value of the diaphragm displacement signal with a threshold.

[0233] At time t10, the diaphragm 206 is in a flat state. Therefore, the value of the diaphragm displacement signal is equal to the reference voltage Vfl, and therefore, the pressed state is determined to be an unused state. As a result, the volume adjustment unit 1809 sets the volume to the mute level. Between times t0 and t1, the value of the diaphragm displacement signal is greater than the threshold voltage Th1. Therefore, the volume adjustment unit 1809 maintains the volume at the mute level.

[0234] At time t11, the value of the diaphragm displacement signal falls below threshold voltage Th1. In response, the pressure detection unit 1805 determines that the pressure state has changed from the unused state to the appropriate state. Therefore, the volume adjustment unit 1809 switches the volume from the mute level to the normal level. However, due to the user applying a strong pressure to the diaphragm 206, at time t12, the value of the diaphragm displacement signal falls below threshold voltage Th2. In response, the pressure detection unit 1805 determines that the pressure state has changed from the appropriate state to the overpressure state. Therefore, the volume adjustment unit 1809 switches the volume from the normal level to the mute level.

[0235] Between times t12 and t14, the value of the diaphragm displacement signal is smaller than threshold voltage Th2, so that after the volume has been switched to the mute level at time t13, volume adjustment unit 1809 maintains the volume at the mute level.

[0236] At time t14, the user reduces the pressure on the diaphragm 206, causing the value of the diaphragm displacement signal to exceed the threshold voltage Th2. In response, the pressure detection unit 1805 determines that the pressure state has changed from an excessive pressure state to an appropriate pressure state. Therefore, the volume adjustment unit 1809 switches the volume from the mute level to the normal level. The volume adjustment unit 1809 may change the volume from the mute level to the normal level over a period of time L3. The period of time L3 may be, for example, 100 ms to 500 ms. The change in volume may be linear or nonlinear.

[0237] The time length L3 may be the same as the time length L1 or may be shorter than the time length L1. When the user reduces the pressure on the diaphragm 206, it is considered that the user is ready to hear the sound signal. Therefore, by making the time length L3 shorter than the time length L1, the sound signal can be delivered to the user more quickly. The time length L3 may be the same as the time length L2 or may be longer than the time length L2.

[0238] Between times t14 and t16, the value of the diaphragm displacement signal is smaller than threshold voltage Th1 and larger than threshold voltage Th2. Therefore, after the volume adjustment unit 1809 has switched the volume to the normal level at time t15, it maintains the volume at the normal level. The operation from time t16 onwards is the same as the operation from time t3 onwards in FIG. 20, and therefore a redundant description will be omitted.

[0239] 23, a specific example of the display unit 122 will be described. The display unit 122 includes four light emitting units 2301 to 2304. Each of the light emitting units 2301 to 2304 is configured by, for example, an LED.

[0240] The light-emitting unit 2301 lights up when the power of the electronic auscultation device 1000 is on, and turns off when the power of the electronic auscultation device 1000 is off. The display control unit 1802 turns on or off the light-emitting unit 2301, allowing the user to easily understand the power status of the electronic auscultation device 1000. Note that the display control unit 1802 may turn off not only the light-emitting unit 2301 but also the light-emitting units 2302 to 2304 when the power of the electronic auscultation device 1000 is off. The display control unit 1802 may also blink the light-emitting unit 2301 for a few seconds after the power of the electronic auscultation device 1000 is turned on, to notify the user that startup processing is being prepared.

[0241] The light-emitting unit 2302 notifies the user that the volume level is at the mute level. For example, the display control unit 1802 turns on the light-emitting unit 2302 when the volume level is at the mute level. The display control unit 1802 turns off the light-emitting unit 2302 when the volume level is at the normal level. This allows the user to easily know that the volume level is at the mute level.

[0242] The light-emitting unit 2303 may notify the user that the pressed state is the in-use state. Specifically, the display control unit 1802 turns on the light-emitting unit 2303 when the pressed state is the in-use state. The display control unit 1802 turns off the light-emitting unit 2303 when the pressed state is not the in-use state (i.e., the unused state). This allows the user to easily understand that the pressed state is the in-use state.

[0243] The light-emitting unit 2304 notifies the user that the pressing state is an overpressure state. For example, the display control unit 1802 turns on the light-emitting unit 2304 when the pressing state is an overpressure state. The display control unit 1802 turns off the light-emitting unit 2304 when the pressing state is not an overpressure state (i.e., an appropriate state or an unused state). This allows the user to easily understand that the pressing state is an overpressure state.

[0244] In this embodiment, the display control unit 1802 notifies the status of the electronic auscultation device 1000 using the light-emitting units 2301 to 2304, but the present invention is not limited to this. For example, if the display unit 122 includes a liquid crystal display, a message may be displayed on the liquid crystal display. Also, a voice message indicating the status of the electronic auscultation device 1000 may be sent to the sound output device 620.

[0245] [Modification of the Power Supply Unit of the Electronic Auscultation Device in the Second Embodiment] A modification of the power supply unit 1710 in FIG. 17A will be described with reference to FIGS. 24A to 24C. The power supply unit 2400 according to the modification illustrated in FIG. 24A differs from the power supply unit 1710 in the position of the boost converter 1713. In the power supply unit 2400, the boost converter 1713 is disposed on the path between the load switch 1715 and the voltage regulator 1716. The voltage VBAT from the charging integrated circuit 1712 is supplied to both the voltage regulator 1714 and the load switch 1715. The voltage VBAT (e.g., 3.7 V) is higher than the output voltage (e.g., 3.3 V) of the voltage regulator 1714. Therefore, the voltage regulator 1714 outputs the voltage V1 while the voltage VBAT is being supplied.

[0246] When load switch 1715 is on, voltage VBAT from charging integrated circuit 1712 is supplied to boost converter 1713. Boost converter 1713 boosts voltage VBAT to a voltage (e.g., 6.8 V) higher than the output voltage (e.g., 5.8 V) of voltage regulator 1716 and supplies this voltage to voltage regulator 1716. Voltage regulator 1716 outputs voltage V2 while voltage is being supplied from boost converter 1713.

[0247] A power supply unit 2410 according to a modified example illustrated in Fig. 24B differs from the power supply unit 1710 in that it further includes a load switch 2411. The boost converter 1713 may be disposed in the position illustrated in Fig. 24A instead of the position illustrated in Fig. 24B.

[0248] The load switch 2411 is a switch that switches between on (conducting state) and off (non-conducting state) in response to a control signal from the microcontroller 1700. A voltage V2 is supplied to the load switch 2411 from the voltage regulator 1716. When the load switch 2411 is on, this voltage V2 is output from the output terminal of the load switch 2411. When the load switch 2411 is off, this voltage V2 is not output from the output terminal of the load switch 2411. When the load switch 2411 is off, the voltage of the output terminal of the load switch 2411 may be the ground voltage.

[0249] When the power supply unit 2410 is used in the electronic auscultation device 1000, operating power for the microphone 1101 may be provided from the voltage regulator 1716 through the load switch 2411. In addition, operating power for the circuit elements included in the microphone signal processing unit 1740 may also be provided from the voltage regulator 1716 through the load switch 2411. On the other hand, even when the power supply unit 2410 is used in the electronic auscultation device 1000, operating power for the light-emitting element 202 and the light-receiving element 204 may be provided directly from the voltage regulator 1716 (i.e., without via the load switch 2411). In addition, operating power for the circuit elements included in the diaphragm displacement signal processing unit 1730 may also be provided from the voltage regulator 1716 through the load switch 2411.

[0250] The power supply unit 2410 allows the microcontroller 1700 (e.g., the power management unit 1804) to stop supplying power to the vibration detection unit 1012 (e.g., including the microphone 1101) while supplying power to the displacement detection unit 1011 (e.g., including the light emitting element 202 and the light receiving element 204). In the power supply unit 2410, a voltage generated by the same voltage regulator 1716 is supplied to the displacement detection unit 1011 and the vibration detection unit 1012. Alternatively, the power supply unit 2410 may include a voltage regulator separate from the voltage regulator 1716 for generating the voltage supplied to the vibration detection unit 1012.

[0251] A power supply unit 2420 according to a modified example illustrated in FIG. 24C differs from the power supply unit 1710 in that it includes load switches 2421 to 2425 instead of the load switch 1715. In the power supply unit 2420, a voltage V0 is supplied directly from a boost converter 1713 to a voltage regulator 1716. The load switches 2421 to 2425 are switches that switch on and off in response to control signals from the microcontroller 1700. A voltage V1 is supplied to the load switches 2421 to 2423 from a voltage regulator 1714. When the load switch 2421 is on, this voltage V1 is output from the output terminal of the load switch 2421. When the load switch 2421 is off, this voltage V1 is not output from the output terminal of the load switch 2421. When the load switch 2421 is off, the voltage at the output terminal of the load switch 2421 may be ground voltage. The same applies to the voltages output from the load switches 2422 to 2423. A voltage V2 is supplied from the voltage regulator 1716 to the load switches 2424 and 2425. When the load switch 2424 is on, this voltage V2 is output from the output terminal of the load switch 2424. When the load switch 2424 is off, this voltage V2 is not output from the output terminal of the load switch 2424. When the load switch 2424 is off, the voltage at the output terminal of the load switch 2424 may be the ground voltage. The same applies to the voltage output from the load switch 2425.

[0252] An output terminal of the load switch 2421 is connected to the display unit 122. While the load switch 2421 is on, a voltage V1 is supplied from the power supply unit 2420 to the display unit 122. The display unit 122 operates using the voltage V1. While the load switch 2421 is off, the voltage V1 is not supplied to the display unit 122. An output terminal of the load switch 2422 is connected to the operation unit 123. While the load switch 2422 is on, a voltage V1 is supplied from the power supply unit 2420 to the operation unit 123. The operation unit 123 operates using the voltage V1. While the load switch 2422 is off, the voltage V1 is not supplied to the operation unit 123. An output terminal of the load switch 2423 is connected to the acceleration sensor 1750. While the load switch 2423 is on, a voltage V1 is supplied from the power supply unit 2420 to the acceleration sensor 1750. The acceleration sensor 1750 operates using the voltage V1. While the load switch 2423 is off, the voltage V1 is not supplied to the acceleration sensor 1750.

[0253] The output terminal of the load switch 2424 is connected to the light-emitting element 202, the light-receiving element 204, and the diaphragm displacement signal processing unit 1730. While the load switch 2424 is on, the power supply unit 2420 supplies a voltage V2 to the light-emitting element 202, the light-receiving element 204, and the diaphragm displacement signal processing unit 1730. The light-emitting element 202, the light-receiving element 204, and the diaphragm displacement signal processing unit 1730 operate using the voltage V2. While the load switch 2424 is off, the voltage V2 is not supplied to the light-emitting element 202, the light-receiving element 204, and the diaphragm displacement signal processing unit 1730. The output terminal of the load switch 2425 is connected to the microphone 1101 and the microphone signal processing unit 1740. While the load switch 2425 is on, the power supply unit 2420 supplies a voltage V2 to the microphone 1101 and the microphone signal processing unit 1740. The microphone 1101 and the microphone signal processing unit 1740 operate using the voltage V2. While the load switch 2425 is off, the voltage V2 is not supplied to the microphone 1101 and the microphone signal processing unit 1740.

[0254] The microcontroller 1700 can individually control the on / off of the load switches 2421 to 2425. Therefore, the microcontroller 1700 can individually set whether to supply operating power to each of the multiple components connected to the output terminals of the load switches 2421 to 2425. In the power supply unit 2420, one or more of the load switches 2421 to 2425 may be omitted, and the voltage V1 or V2 may be directly supplied to the components.

[0255] [Modification of the Wired Communication Unit of the Electronic Auscultation Device in the Second Embodiment] With reference to FIGS. 25A and 25B , a modification of the wired communication unit 617 in FIG. 17A will be described. In the modification illustrated in FIG. 25A , the wired communication unit 617 is configured by the connector 125 and a charging integrated circuit 1712. The microcontroller 1700 may be able to communicate with the charging integrated circuit 1712 via, for example, I2C. The charging integrated circuit 1712 may also be able to communicate with an external device connected to the connector 125. In such a configuration, the charging integrated circuit 1712 may support charging via USB Power Delivery (USB PD). In the modification illustrated in FIG. 25B , the wired communication unit 617 is configured by the connector 125. The microcontroller 1700 may also be able to directly communicate with the external device connected to the connector 125.

[0256] [Operation Modes of the Electronic Auscultation Device in the Second Embodiment] An example of transitions between operation modes of the electronic auscultation device 1000 will be described with reference to FIG. 26A . The electronic auscultation device 1000 in the second embodiment can operate in multiple operation modes, including a power-saving mode 2601, a heartbeat sound mode 2602, and a breath sound mode 2603. The power-saving mode 2601 consumes less power than the heartbeat sound mode 2602 and the breath sound mode 2603. To reduce power consumption, in this embodiment, the electronic auscultation device 1000 is configured to switch to the power-saving mode 2601 under certain conditions, such as when not in use. The heartbeat sound mode 2602 is an operation mode used to auscultate heartbeat sounds and is one of the auscultation modes. In the heartbeat sound mode 2602 in this embodiment, a voltage V1 is supplied to the microcontroller 1700, and a voltage V2 is also supplied to the optical sensor including the light-emitting element 202 and the light-receiving element 204. In the heartbeat sound mode 2602, a heartbeat sound signal can be transmitted to an external device (e.g., a computer 630 or a sound output device 620) using the light-emitting element 202 and the light-receiving element 204. The breath sound mode 2603 is an operating mode used to auscultate breath sounds and is one of the auscultation modes. In the breath sound mode 2603 of this embodiment, the voltage V1 is supplied to the microcontroller 1700, and the voltage V2 is also supplied to the microphone 1101. In the breath sound mode 2603, a breath sound signal can be output to an external device using the microphone 1101. The electronic auscultation device 1000 may further operate in an operating mode in which both the heartbeat sound signal and the breath sound signal are transmitted to an external device (e.g., a computer 630). However, in the case of an electronic auscultation device that does not include the microphone 1101, as in the first embodiment, the breath sound mode 2603 is not included.

[0257] In any of the power saving mode 2601, the heartbeat sound mode 2602, and the breath sound mode 2603, the power supply unit 2400 supplies operating power to the microcontroller 1700. Specifically, the voltage regulator 1714 generates a voltage V1 and supplies the voltage V1 to the microcontroller 1700. As described above, the voltage V1 is also supplied to the acceleration sensor 1750.

[0258] In the power saving mode 2601, the microcontroller 1700 at least intermittently turns off the load switch 1715. For example, in the power saving mode 2601, the microcontroller 1700 intermittently turns off (i.e., intermittently turns on) the load switch 1715. In this case, the voltage regulator 1716 generates the voltage V2 intermittently. Alternatively, in the power saving mode 2601, the microcontroller 1700 may always turn off the load switch 1715. In this case, the voltage regulator 1716 does not generate the voltage V2. When the voltage V2 is not generated, the supply of operating power to the light emitting element 202, the light receiving element 204, and the microphone 1101 is stopped, and these circuit elements do not operate.

[0259] In the heartbeat sound mode 2602 and the breath sound mode 2603, the microcontroller 1700 may keep the load switch 1715 on all the time. Alternatively, in the heartbeat sound mode 2602 and the breath sound mode 2603, the microcontroller 1700 may keep the load switch 1715 on more frequently than in the power saving mode 2601. When the load switch 1715 is on, the voltage regulator 1716 generates a voltage V2. When the voltage V2 is generated, an operating voltage is supplied to the light emitting element 202 and the light receiving element 204, so that these circuit elements operate. In the above example, the voltage V2 is higher than the voltage V1. When the operating voltage of the light emitting element 202 and the light receiving element 204 is lower than the operating voltage of the microcontroller 1700, the voltage V2 may be lower than the voltage V1. When the electronic stethoscope device 1000 has the power supply unit 1710 or the power supply unit 2400, the load switch 1715 is turned on, and operating power is also supplied to the microphone 1101.

[0260] If the electronic auscultation device 1000 has a power supply unit 2410, the microcontroller 1700 may keep the load switch 2411 always off in the heartbeat sound mode 2602. If the electronic auscultation device 1000 has a power supply unit 2410, the microcontroller 1700 may keep the load switch 2411 always on in the breath sound mode 2603.

[0261] As described above, the power supplied to the light emitting element 202 and the light receiving element 204 in the power saving mode 2601 is less than the power supplied to the light emitting element 202 and the light receiving element 204 in the heartbeat sound mode 2602 and the breath sound mode 2603. Furthermore, the power supplied to the microphone 1101 in the power saving mode 2601 is less than the power supplied to the microphone 1101 in the breath sound mode 2603. The power supplied to the microphone 1101 in the heartbeat sound mode 2602 may be less than the power supplied to the microphone 1101 in the heartbeat sound mode 2602. With this configuration, the electronic auscultation device 1000 is made more power-efficient.

[0262] The electronic auscultation device 1000 may have multiple power-saving modes. The multiple power-saving modes are realized by the electronic auscultation device 1000 having a power supply unit 2420 (FIG. 24C). The power supply to the components in each mode will be described with reference to Table 4 below. (Table 4) In the example of Table 4, the electronic auscultation device 1000 has four power saving modes A to D. In Table 4, "ON" indicates that power is supplied to the components, and "OFF" indicates that power is not supplied to the components. The displacement detection unit 1011 includes a light emitting element 202, a light receiving element 204, and a diaphragm displacement signal processing unit 1730. The vibration detection unit 1012 includes a microphone 1101 and a microphone signal processing unit 1740.

[0263] When the electronic auscultation device 1000 is operating in the heartbeat sound mode, the microcontroller 1700 turns on the load switches 2421 to 2424 and turns off the load switch 2425. As a result, operating power is supplied to the display unit 122, the operation unit 123, the acceleration sensor 1750, and the displacement detection unit 1011, but operating power is not supplied to the vibration detection unit 1012. When the electronic auscultation device 1000 is operating in the breath sound mode, the microcontroller 1700 turns on the load switches 2421 to 2423 and 2425 and turns off the load switch 2424. As a result, operating power is supplied to the display unit 122, the operation unit 123, the acceleration sensor 1750, and the vibration detection unit 1012, but operating power is not supplied to the displacement detection unit 1011.

[0264] While the electronic auscultation device 1000 is operating in power saving mode A, the microcontroller 1700 turns on the load switch 2422 and turns off the load switches 2421 and 2423 to 2425. As a result, operating power is supplied to the operation unit 123, but operating power is not supplied to the display unit 122, the acceleration sensor 1750, the displacement detection unit 1011, and the vibration detection unit 1012. The microcontroller 1700 returns from power saving mode A in response to the operation of the operation unit 123 by the user. Specifically, the microcontroller 1700 returns from power saving mode A in response to the operation of any of the buttons on the operation unit 123 by the user. In this case, each button on the operation unit 123 has a function of receiving an instruction from the user regarding the mode transition of the electronic auscultation device 1000. The operating power of the operation unit 123 is smaller than the operating power of any of the display unit 122, the acceleration sensor 1750, the displacement detection unit 1011, and the vibration detection unit 1012. Therefore, power saving mode A consumes less power than any of power saving modes B to D.

[0265] While the electronic auscultation device 1000 is operating in power-saving mode B, the microcontroller 1700 turns on the load switch 2423 and turns off the load switches 2421, 2422, 2424, and 2425. This supplies operating power to the acceleration sensor 1750, but does not supply operating power to the display unit 122, the operation unit 123, the displacement detection unit 1011, or the vibration detection unit 1012. The microcontroller 1700 returns from power-saving mode B in response to the acceleration sensor 1750 detecting a predetermined motion. For example, the microcontroller 1700 returns from power-saving mode B when the upward acceleration of the electronic auscultation device 1000 (the direction opposite to gravity) is greater than a threshold. Such acceleration can occur when the electronic auscultation device 1000 is lifted by the user. Therefore, the microcontroller 1700 returns from power-saving mode B in response to a natural motion performed by the user to use the electronic auscultation device 1000.

[0266] In the above example, the acceleration sensor 1750 is used to return from power saving mode B, but an electrostatic sensor may be used instead of the acceleration sensor 1750. The electrostatic sensor is provided on the surface of the grip portion 120 and is used to detect that the user has gripped the grip portion 120. While the electronic auscultation device 1000 is operating in power saving mode B, the microcontroller 1700 supplies operating power to the electrostatic sensor. The microcontroller 1700 returns from power saving mode B in response to detecting that the user has touched the electrostatic sensor. Even in this case, the microcontroller 1700 returns from power saving mode B in response to a natural action performed by the user to use the electronic auscultation device 1000.

[0267] While the electronic auscultation device 1000 is operating in power-saving mode C, the microcontroller 1700 turns on the load switch 2424 and turns off the load switches 2421 to 2423 and 2425. This causes operating power to be supplied to the displacement detection unit 1011, but not to the display unit 122, operation unit 123, acceleration sensor 1750, and vibration detection unit 1012. The microcontroller 1700 returns from power-saving mode C in response to the diaphragm 206 being pressed. For example, the microcontroller 1700 returns from power-saving mode C when the output from the light-receiving element 204 corresponding to the amount of displacement of the diaphragm 206 (i.e., the diaphragm displacement signal) exceeds a threshold. In this way, the microcontroller 1700 returns from power-saving mode C in response to a natural action performed by the user to use the electronic auscultation device 1000.

[0268] While the electronic auscultation device 1000 is operating in power saving mode D, the microcontroller 1700 turns on the load switch 2425 and turns off the load switches 2421 to 2424. As a result, operating power is supplied to the vibration detection unit 1012, but operating power is not supplied to the display unit 122, the operation unit 123, the acceleration sensor 1750, and the displacement detection unit 1011. The microcontroller 1700 returns from power saving mode D in response to the microphone 1101 detecting a predetermined sound. For example, the microcontroller 1700 returns from power saving mode D in response to the microphone 1101 detecting a sound with a wavelength corresponding to a respiratory sound. In this way, the microcontroller 1700 returns from power saving mode D in response to a natural action performed by the user to use the electronic auscultation device 1000.

[0269] In power saving modes B to D, the electronic auscultation device 1000 returns from the power saving modes without the user operating the operation unit 123. Which of power saving modes A to D will be used may be set at the time of shipping the electronic auscultation device 1000. Furthermore, which of power saving modes A to D will be used may be set by the user. Furthermore, the electronic auscultation device 1000 does not need to have one or more of power saving modes A to D. The electronic auscultation device 1000 may have a power saving mode other than power saving modes A to D in Table 4. For example, the electronic auscultation device 1000 may have a power saving mode in which only two or more specific load switches among the load switches 2422 to 2425 are turned on.

[0270] Referring to FIG. 26B , the operation for transitioning from heartbeat sound mode 2602 to power saving mode 2601 will be described. Power saving mode 2601 is a pre-set power saving mode among power saving modes A to D. Each step of the method in FIG. 26B is implemented by processor 1701 executing a program stored in non-volatile memory 1702. However, some or all of the steps of the method in FIG. 26B may be implemented by a dedicated integrated circuit. Processor 1701 starts the method in FIG. 26B in response to the electronic auscultation device 1000 entering heartbeat sound mode 2602. The operation for transitioning from breath sound mode 2603 to power saving mode 2601 is also similar to that in FIG. 26B .

[0271] In S2611, the processor 1701 starts a timer. In S2612, the processor 1701 determines whether the user is using the electronic auscultation device 1000. If the processor 1701 determines that the user is using the electronic auscultation device 1000 ("YES" in S2612), the processor 1701 resets the timer in S2613 and then transitions the process to S2614. If the processor 1701 determines that the user is not using the electronic auscultation device 1000 ("NO" in S2612), the processor 1701 transitions the process to S2614 without resetting the timer. If the timer is not reset, the timer value continues to increment.

[0272] The processor 1701 may determine whether the user is using the electronic auscultation device 1000 based on at least one of a plurality of conditions. For example, the processor 1701 determines that the user is using the electronic auscultation device 1000 when at least one of the following conditions is met: the diaphragm 206 is in a pressed state, the microphone 1101 is detecting sound, the measurement value of the acceleration sensor 1750 exceeds a threshold, and Bluetooth communication is established. Alternatively, the processor 1701 may determine that the user is using the electronic auscultation device 1000 when all of these conditions are met.

[0273] At S2614, the processor 1701 determines whether an instruction to transition to power saving mode has been received from the user. If it is determined that an instruction to transition to power saving mode has been received from the user ("YES" at S2614), the processor 1701 transitions the process to S2616; otherwise ("NO" at S2614), the processor 1701 transitions the process to S2615. At S2615, the processor 1701 determines whether the timer value has exceeded the threshold. If it is determined that the timer value has exceeded the threshold ("YES" at S2615), the processor 1701 transitions the process to S2616; otherwise ("NO" at S2615), the processor 1701 transitions the process to S2612.

[0274] In this way, when the processor 1701 receives an instruction to transition to the power saving mode from the user or when the timer value exceeds the threshold, the processor 1701 transitions to the power saving mode in S2616. In other cases, the processor 1701 repeats S2612 to S2615. By repeating S2612 to S2615, the timer indicates the elapsed time since it was determined that the user had finished using the electronic auscultation device 1000. Therefore, the processor 1701 transitions to the power saving mode without an explicit transition instruction from the user when a predetermined time (the threshold of S2615) has elapsed since it was determined that the user had finished using the electronic auscultation device 1000. For example, if the output from the light receiving element 204 (i.e., the diaphragm displacement signal) does not change for a certain period of time, the processor 1701 determines that a predetermined time (threshold of S2615) has elapsed since it was determined that the user had finished using the electronic auscultation device 1000, and transitions the mode of the electronic auscultation device 1000 to power saving mode.

[0275] The operation for returning from the power saving mode 2601 will be described with reference to Fig. 26C. The power saving mode 2601 is a preset power saving mode among the power saving modes A to D. Each step of the method in Fig. 26C is executed by, for example, the processor 1701. However, some or all of the steps of the method in Fig. 26C may be realized by a dedicated integrated circuit. The processor 1701 starts the method in Fig. 26C in response to the electronic auscultation device 1000 entering the power saving mode 2601.

[0276] In S2621, the processor 1701 determines whether the conditions for returning from the power saving mode 2601 (hereinafter, the return conditions) have been met. If it is determined that the return conditions have been met ("YES" in S2621), the processor 1701 transitions the process to S2622, and otherwise ("NO" in S2621), the processor 1701 repeats S2621. In S2622, the processor 1701 returns from the power saving mode 2601.

[0277] The recovery condition differs depending on the power saving mode 2601, as described above with reference to Table 4. For example, as described above, in power saving mode A, the recovery condition is that the operation unit 123 is operated by the user. The recovery condition may also be that at least one of the conditions related to the components to which operating power is supplied via the on-state load switches is satisfied while the electronic auscultation device 1000 is operating in a power saving mode in which only two or more specific load switches among the load switches 2422 to 2425 are turned on.

[0278] [Transition of Operation Modes of the Electronic Auscultation Device in the Second Embodiment] Next, transitions between operation modes will be described. In the power saving mode 2601, the microcontroller 1700 identifies the state of the electronic auscultation device 1000. Based on this identified state, the microcontroller 1700 may transition from the power saving mode 2601 to the heartbeat sound mode 2602 or the breath sound mode 2603. The microcontroller 1700 transitions to the heartbeat sound mode 2602 when the current setting set by the output selection unit 1807 is a heartbeat sound signal, and transitions to the breath sound mode 2603 when this setting is a breath sound signal. As described above, the setting set by the output selection unit 1807 may be changeable by a user input via the operation unit 123. In the following description, it is assumed that the heartbeat sound signal is set by the output selection unit 1807.

[0279] For example, in the power saving mode 2601, the microcontroller 1700 identifies the state of the diaphragm 206 based on the diaphragm displacement signal. Specifically, the identified state of the electronic auscultation device 1000 is the state of the diaphragm 206. In this case, the microcontroller 1700 transitions from the power saving mode 2601 to the heartbeat sound mode 2602 based on the state of the diaphragm 206. In the power saving mode 2601, the microcontroller 1700 turns on the load switch 1715 intermittently (e.g., every 10 ms to 100 ms) to acquire the diaphragm displacement signal, and turns off the load switch 1715 in response to acquisition of the diaphragm displacement signal.

[0280] The microcontroller 1700 transitions from the power saving mode 2601 to the heartbeat sound mode 2602 when the pressure state of the diaphragm 206 changes from the unused state to the used state described above. For example, the microcontroller 1700 transitions from the power saving mode 2601 to the heartbeat sound mode 2602 when the pressure state of the diaphragm 206 changes from the unused state to the used state.

[0281] Furthermore, in the power saving mode 2601, the microcontroller 1700 identifies the movement of the electronic auscultation device 1000 based on the acceleration signal output from the acceleration sensor 1750. That is, the identified state of the electronic auscultation device 1000 is the movement of the electronic auscultation device 1000. In this case, the microcontroller 1700 transitions from the power saving mode 2601 to the heartbeat sound mode 2602 based on the movement of the electronic auscultation device 1000 detected by the acceleration sensor 1750. When the state of the electronic auscultation device 1000 is identified using the acceleration signal, the diaphragm displacement signal does not need to be used, and therefore the microcontroller 1700 can also keep the load switch 1715 off at all times in the power saving mode 2601.

[0282] On the other hand, the microcontroller 1700 transitions from the power saving mode 2601 to the heartbeat sound mode 2602 when the acceleration of the electronic auscultation device 1000 exceeds a threshold acceleration. For example, the microcontroller 1700 may immediately transition from the power saving mode 2601 to the heartbeat sound mode 2602 when the acceleration of the electronic auscultation device 1000 exceeds a threshold acceleration. The threshold acceleration is set to a value that allows detection of a user's movement of the electronic auscultation device 1000.

[0283] The above-described transitions based on the diaphragm displacement signal and the above-described transitions based on the acceleration signal may be combined. For example, the microcontroller 1700 may transition from the power save mode 2601 to the heartbeat sound mode 2602 when either a condition related to the diaphragm displacement signal or a condition related to the acceleration signal is satisfied. Alternatively, the microcontroller 1700 may transition from the power save mode 2601 to the heartbeat sound mode 2602 when both a condition related to the diaphragm displacement signal and a condition related to the acceleration signal are satisfied.

[0284] Furthermore, in this embodiment, the microcontroller 1700 can also transition from the power saving mode 2601 to the heartbeat sound mode 2602 based on receiving an instruction from the user to transition from the power saving mode 2601 to the heartbeat sound mode 2602. For example, when the power switch 124 is operated by the user, the microcontroller 1700 receives an instruction to transition from the power saving mode 2601 to the heartbeat sound mode 2602. Alternatively, the operation unit 123 may include a button for receiving such an instruction from the user. Furthermore, in the power saving mode 2601, the microcontroller 1700 may monitor a pairing request from an external device to the Bluetooth circuit 1703. The microcontroller 1700 may transition from the power saving mode 2601 to the heartbeat sound mode 2602 based on receiving a pairing request from the external device.

[0285] Next, a specific description will be given of the transition from the heartbeat sound mode 2602 to the power saving mode 2601. The transition from the breath sound mode 2603 to the power saving mode 2601 is similar to the transition from the heartbeat sound mode 2602 to the power saving mode 2601, and therefore a duplicated description will be omitted. The microcontroller 1700 also identifies the state of the electronic auscultation device 1000 in the heartbeat sound mode 2602. The microcontroller 1700 may transition from the heartbeat sound mode 2602 to the power saving mode 2601 based on this identified state.

[0286] For example, in heartbeat sound mode 2602, microcontroller 1700 determines the state of diaphragm 206 based on the diaphragm displacement signal. Microcontroller 1700 transitions from heartbeat sound mode 2602 to power save mode 2601 based on the depression state of diaphragm 206 being the above-described unused state. For example, microcontroller 1700 transitions from heartbeat sound mode 2602 to power save mode 2601 in response to a change in the depression state of diaphragm 206 from a used state to a unused state. Alternatively, microcontroller 1700 may transition from heartbeat sound mode 2602 to power save mode 2601 in response to a non-use state continuing for a predetermined threshold time (e.g., 5 seconds) or more.

[0287] For example, in the heartbeat sound mode 2602, the microcontroller 1700 determines the movement of the electronic auscultation device 1000 based on the acceleration signal output from the acceleration sensor 1750. The microcontroller 1700 may transition from the heartbeat sound mode 2602 to the power saving mode 2601 based on the acceleration of the electronic auscultation device 1000 being lower than a threshold acceleration. For example, the microcontroller 1700 may transition from the heartbeat sound mode 2602 to the power saving mode 2601 based on the state in which the acceleration of the electronic auscultation device 1000 is lower than the threshold acceleration continuing for a predetermined threshold time (e.g., 5 seconds) or more.

[0288] The above-described transitions based on the diaphragm displacement signal and the above-described transitions based on the acceleration signal may be combined. For example, the microcontroller 1700 may transition from the heartbeat sound mode 2602 to the power save mode 2601 when either a condition related to the diaphragm displacement signal or a condition related to the acceleration signal is satisfied. Alternatively, the microcontroller 1700 may transition from the heartbeat sound mode 2602 to the power save mode 2601 when both a condition related to the diaphragm displacement signal and a condition related to the acceleration signal are satisfied.

[0289] Furthermore, the microcontroller 1700 can also make the above-described transition based on receiving an instruction from the user to transition from the heartbeat sound mode 2602 to the power saving mode 2601. For example, when the power switch 124 is operated by the user, an instruction to transition from the power saving mode 2601 to the heartbeat sound mode 2602 is received, and the transition from the heartbeat sound mode 2602 to the power saving mode 2601 may be made, or the transition from the heartbeat sound mode 2602 to the power saving mode 2601 may be made based on an instruction via a button included in the operation unit 123.

[0290] A specific example of transitions between operating modes will be described with reference to Figures 27A and 27B. Figure 27A describes transitions based on an acceleration signal. Graph 2701 shows the voltage at the output terminal of the voltage regulator 1716. Graph 2702 shows the acceleration signal. At time t20, the electronic auscultation device 1000 is operating in the power saving mode 2601. Therefore, the voltage at the output terminal of the voltage regulator 1716 becomes the ground voltage. At time t21, the acceleration signal exceeds the threshold acceleration Th3. In response, the microcontroller 1700 transitions the electronic auscultation device 1000 from the power saving mode 2601 to the heartbeat sound mode 2602. As a result, the voltage at the output terminal of the voltage regulator 1716 becomes voltage V2.

[0291] At time t22, the acceleration signal falls below the threshold acceleration Th3, and in response, the microcontroller 1700 transitions the electronic auscultation device 1000 from the heartbeat sound mode 2602 to the power saving mode 2601. This causes the voltage at the output terminal of the voltage regulator 1716 to become the ground voltage.

[0292] FIG. 27B illustrates a transition based on the diaphragm displacement signal. Graph 2711 shows the voltage at the output terminal of the voltage regulator 1716. Graph 2712 shows the diaphragm displacement signal. Graph 2713 shows the heartbeat sound signal. Time t30 indicates the point in time when the electronic auscultation device 1000 starts up and operates in the heartbeat sound mode 2602. At time t30, the voltage at the output terminal of the voltage regulator 1716 becomes voltage V2. When the diaphragm displacement signal exceeds the threshold voltage Th1, the microcontroller 1700 sets a timer and measures time. Then, when the diaphragm displacement signal has continuously exceeded the threshold voltage Th1 for a predetermined time (e.g., 5 seconds), the microcontroller 1700 executes a process to transition to the power saving mode 2601.

[0293] On the other hand, if the microcontroller 1700 detects that the diaphragm displacement signal has fallen below the threshold voltage Th1 while the timer is set and measuring time, it resets the timer. In the example of FIG. 27B , assume that at time t31, the duration during which the diaphragm displacement signal is greater than the threshold voltage Th1 reaches a predetermined time (e.g., 5 seconds). In response, the microcontroller 1700 transitions the electronic auscultation device 1000 from the heartbeat sound mode 2602 to the power-saving mode 2601. As a result, the voltage at the output terminal of the voltage regulator 1716 becomes the ground voltage.

[0294] In this embodiment, an example has been described in which the electronic auscultation device 1000 transitions to the power saving mode 2601 when a predetermined time has elapsed since the diaphragm displacement signal exceeded the threshold voltage Th1. However, as another example, the electronic auscultation device 1000 may transition to the power saving mode 2601 when the diaphragm displacement signal has exceeded the threshold voltage Th1 a predetermined number of times. In addition, the transition condition to the power saving mode 2601 in this embodiment is set to 5 seconds after the diaphragm displacement signal exceeded the threshold voltage Th1. However, the time required to transition to the power saving mode may be variably set by the user depending on the environment in which the electronic auscultation device 1000 is used.

[0295] Thereafter, the microcontroller 1700 intermittently turns on the load switch 1715. As a result, the voltage at the output terminal of the voltage regulator 1716 becomes V2 intermittently. At time t32, the diaphragm displacement signal falls below the threshold voltage Th1. In response, the microcontroller 1700 transitions the electronic auscultation device 1000 from the power saving mode 2601 to the heartbeat sound mode 2602. As a result, the voltage at the output terminal of the voltage regulator 1716 is maintained at voltage V2.

[0296] As described above, the electronic auscultation device 1000 of this embodiment has multiple operating modes, including a heartbeat sound mode 2602, a breath sound mode 2603, and a power-saving mode 2601. The microcontroller 1700 executes a transition process to one of the multiple operating modes based on (1) a diaphragm displacement signal output from the light-receiving element 204, (2) an acceleration signal output from the acceleration sensor 1750, and / or (3) a user input via the operation unit 123. According to this embodiment, the electronic auscultation device 1000 transitions to the power-saving mode 2601 when not in use, thereby reducing power consumption and battery drain. As a result, the operating time of the electronic auscultation device 1000 can be extended. Furthermore, the electronic auscultation device 1000 returns from the power-saving mode 2601 when it is ready for use, improving user operability.

[0297] Note that the conditions for transitioning to the power saving mode 2601 and the conditions for returning from the power saving mode 2601 are not limited to the above (1) to (3), and other conditions may be used for transitioning to or returning from the power saving mode 2601. An example will be described. For example, in the power saving mode 2601, the microcontroller 1700 may monitor a pairing request from an external device to the Bluetooth circuit 1703, and control the transition of the operating mode based on the monitoring result. When the microcontroller 1700 receives a pairing request from the external device, it transitions from the power saving mode 2601 to the heartbeat sound mode 2602 or the breath sound mode 2603.

[0298] The power saving mode 2601 can also be entered or exited by a user input via the operation unit 123 alone. In this case, it is not necessary to turn on the load switch 1715 intermittently while the power saving mode 2601 is active, thereby achieving a higher power consumption effect. The power saving mode 2601 can also be entered or exited by pressing and holding the power switch 124.

[0299] The user may be notified of the transition of the operation mode when transitioning from the heartbeat sound mode 2603 or the breath sound mode 2603 to the power saving mode 2601, or when returning from the power saving mode 2601 to the heartbeat sound mode 2603 or the breath sound mode 2603. Specifically, the display control unit 1802 controls the light emitting unit 2301 to blink for a certain period of time (e.g., several seconds). This blinking process notifies the user of the transition of the operation mode.

[0300] Third Embodiment [Configuration Example of an Electronic Auscultation Device in the Third Embodiment] A configuration example of an electronic auscultation device 2800 according to the third embodiment will be described with reference to FIGS. 28A to 30 . The electronic auscultation device described above includes a chestpiece, which is the part that contacts the patient's skin, and a gripping portion that includes relatively heavy components such as a battery. When contacting the chestpiece with the patient's skin, if the gripping portion held by the user is fixed to the chestpiece, it may be difficult to contact the chestpiece evenly with the skin depending on the patient's posture (e.g., lying down, sitting, standing). Furthermore, when the electronic auscultation device is not in use, depending on the angle between the chestpiece and the gripping portion, it may take up space or be difficult to store. Therefore, one of the features of the electronic auscultation device 2800 according to the third embodiment is that the chestpiece 2810 is connected to the gripping portion 2820 so that it can swing relative to the gripping portion 2820. The following mainly describes the differences from the electronic auscultation device 1000 according to the second embodiment. The differences between the second and third embodiments may be applied to the first embodiment. The appearance of the electronic auscultation device 2800 is similar to that of the electronic auscultation device 100 described with reference to FIGS. 1A and 1B. The modifications described in the first or second embodiments may also be applied to the third embodiment. Specifically, the displacement detection unit 1011 and the vibration detection unit 1012 according to the second embodiment may be provided in the chestpiece 2810 of the electronic auscultation device 2800 according to the third embodiment. In this case, the relay circuit board 1103 and the hole 208a may be located inside the chestpiece 2810 and outside the sealed space 1100. This allows the chestpiece 2810 to be swung without impairing the sound detection sensitivity of the microphone.

[0301] Electronic auscultation device 2800 has a chestpiece 2810 and a gripping portion 2820. Chestpiece 2810 is similar to chestpiece 1010 of electronic auscultation device 1000, except for differences described below, and gripping portion 2820 is similar to gripping portion 120 of electronic auscultation device 1000.

[0302] [Appearance of the Electronic Auscultation Device in the Third Embodiment] Figures 28A and 28B are perspective views of a portion of an electronic auscultation device 2800, including a chestpiece 2810, viewed from various angles. Figure 28C is a perspective view of the chestpiece 2810. Figure 28D is a perspective view of a grip portion 2820.

[0303] The chestpiece 2810 is coupled to the gripping portion 2820 so as to be able to swing relative to the gripping portion 2820. Specific configuration examples that enable such coupling will be described below. The chestpiece 2810 may be configured to be able to swing relative to the gripping portion 2820 in a different configuration from that described below. By allowing the chestpiece 2810 to swing relative to the gripping portion 2820, the contact surface 206a of the diaphragm 206 can be more easily brought into close contact with the surface of a living body when the electronic auscultation device 2800 is in use, allowing the electronic auscultation device 2800 to accurately detect displacement of the surface of a living body.

[0304] The chestpiece 2810 includes a connecting member 2811 attached to approximately the center of the top surface of the housing 208. The connecting member 2811 is provided on a protrusion formed approximately in the center of the top surface of the housing 208. The connecting member 2811 may be made of the same metal as the housing 208, or may be made of a different material (for example, resin). The connecting member 2811 may also be part of the housing 208, or the connecting member 2811 and the housing 208 may be molded integrally.

[0305] The coupling member 2811 includes a central portion 2811a and a pivot shaft 2811b. The pivot shaft 2811b extends outward from the central portion 2811a. The pivot shaft 2811b has two ends positioned opposite each other, with the central portion 2811a located between the two ends. The pivot shaft 2811b extends approximately parallel to the contact surface 206a of the diaphragm 206. The pivot shaft 2811b has a cylindrical surface. Specifically, the cross section of the pivot shaft 2811b taken along the x-z plane is circular. In this specification, "a line and a plane are approximately parallel" means that the angle between the line and the plane is between 0° and 10°. Furthermore, "two lines are approximately parallel" means that the angle between the two lines is between 0° and 10°. "A line and a plane are approximately perpendicular" means that the angle between the line and the plane is between 80° and 90°. Furthermore, "two straight lines intersect substantially perpendicularly" means that the angle between the two straight lines is between 80° and 90°. Here, the "angle" refers to the angle between the two lines that is in the range of between 0° and 90°.

[0306] The grip portion 2820 has a housing 2821 made of resin, which houses a battery 2911 and a main circuit board 2910 (described later). The grip portion 2820 is rod-shaped, with the chestpiece 2810 attached to one end. The direction in which the grip portion 2820 extends is referred to as the longitudinal direction of the grip portion 2820. For example, the longitudinal direction of the grip portion 2820 is the direction in which the longest line segment included on the outer surface of the housing 2821 of the grip portion 2820 extends. The longitudinal direction of the grip portion 2820 also refers to the direction in which the long side of a circuit board (described later) housed in the housing 2821 extends. The housing 2821 is sized so that it can be held by a user. Specifically, the length of the housing 2821 (e.g., the size of the grip portion 2820 in the longitudinal direction) is within a range of 50 mm to 150 mm, for example. The length of the periphery of the housing 2821 around the longitudinal direction is, for example, in the range of 50 mm to 200 mm.

[0307] As shown in FIG. 28D , the housing 2821 has two receiving portions 2821a. One receiving portion 2821a engages with one end of the pivot shaft 2811b, and the other receiving portion 2821a engages with the other end of the pivot shaft 2811b. This allows the chestpiece 2810 to be coupled to the grip portion 2820 so as to be pivotable relative to the grip portion 2820. Specifically, in this configuration, the chestpiece 2810 pivots relative to the grip portion 2820 around the pivot shaft 2811b along a plane (xz plane) perpendicular to the direction in which the pivot shaft 2811b extends. In this specification, "the chestpiece 2810 is pivotable relative to the grip portion 2820" means that the angle of the contact surface 206a of the diaphragm 206 relative to the longitudinal direction of the grip portion 2820 is variable. The chestpiece 2810 may be pivotable in other ways relative to the grip portion 2820. For example, the chestpiece 2810 may be pivotable relative to the grip portion 2820 without having a specific rotation axis, and may be pivotable by sliding on a rail that includes a curved portion, for example.

[0308] The receiving portion 2821a has a recess or hole into which the rotating shaft 2811b is inserted, and rotatably supports the rotating shaft 2811b. The two receiving portions 2821a are provided at positions facing each other with a space between them, and the central portion 2811a of the connecting member 2811 is disposed in this space. The chestpiece 2810 is connected to the gripping portion 2820 so that the rotating shaft 2811b overlaps the diaphragm 206 in a plan view of the contact surface 206a of the diaphragm 206. This allows the user to naturally grip the gripping portion 2820 while bringing the contact surface 206a of the diaphragm 206 into close contact with the surface of the living body.

[0309] 29A to 29D, cross-sectional views of the electronic auscultation device 2800 taken along a plane parallel to the xz plane and passing through the central portion 2811a of the coupling member 2811 will be described. Fig. 29A shows the chestpiece 2810 at one end of the range in which it can swing relative to the gripping portion 2820, and Fig. 29B shows the chestpiece 2810 at the other end of the range in which it can swing relative to the gripping portion 2820. In other words, the chestpiece 2810 can swing (specifically, rotate) relative to the gripping portion 2820 between the position shown in Fig. 29A and the position shown in Fig. 29B.

[0310] In the following description, the position shown in FIG. 29A is referred to as the home position of the chestpiece 2810, and the position shown in FIG. 29B is referred to as the inverted position of the chestpiece 2810. The home position may be the position where the chestpiece 2810 stops when rotated counterclockwise around the rotation axis 2811b in FIGS. 29A to 29D. The inverted position is the position where the chestpiece 2810 stops when rotated clockwise around the rotation axis 2811b in FIGS. 29A to 29D. For example, it is desirable that the chestpiece 2810 be rotatable by 60° or more relative to the grip portion 2820. For example, the upper limit of the range in which the chestpiece 2810 can rotate relative to the grip portion 2820 may be 80°, 90°, or 100°.

[0311] When the chestpiece 2810 is in the home position ( FIG. 29A ), the angle between the longitudinal direction (e.g., the x-axis direction) of the gripping portion 2820 and the contact surface 206 a of the diaphragm 206 is preferably between 0° and 45°. Furthermore, this angle may be 30° or less, or may be 15° or less. When the chestpiece 2810 is in the inverted position ( FIG. 29B ), the angle between the longitudinal direction (e.g., the x-axis direction) of the gripping portion 2820 and the contact surface 206 a of the diaphragm 206 may be between 80° and 90°. Furthermore, this angle may be 70° or more, or may be 60° or more.

[0312] The grip portion 2820 includes a main circuit board 2910 and a battery 2911. The main circuit board 2910 includes circuit elements (e.g., integrated circuits, electrode pads, conductive patterns, etc.) for controlling the overall operation of the electronic auscultation device 2800. Specifically, the main circuit board 2910 controls the operation of the chestpiece 2810, the operation of the display unit 122, and the operation of the operation unit 123. For example, the main circuit board 2910 constitutes the above-mentioned sound output unit 1020 ( FIG. 10 ). The main circuit board 2910 may be plate-shaped and may have a mounting surface parallel to the xy plane. As described above, the longitudinal direction of the main circuit board 2910 (e.g., the direction in which the long sides of the mounting surface extend) may be considered to be the longitudinal direction of the grip portion 2820.

[0313] The battery 2911 stores power used by the electronic auscultation device 2800. In this embodiment, the battery 2911 has a plate-like or columnar shape, and the longitudinal direction of the battery 2911 coincides with the longitudinal direction of the grip portion 2820.

[0314] The electronic auscultation device 2800 includes a cable 2920 that connects the relay circuit board 1103 of the chestpiece 2810 and the main circuit board 2910 of the gripping portion 2820. Specifically, the cable 2920 includes a connector 2922 for connecting to a connector 2913 provided on the main circuit board 2910 of the gripping portion 2820, and a connector 2921 for connecting to the relay circuit board 1103 (specifically, its connector) of the chestpiece 2810. The connectors 2921 and 2922 are located at opposite ends of the cable 2920.

[0315] As described above, the chestpiece 2810 is formed with a hole 208a through which the cable 2920 passes. Furthermore, the gripping portion 2820 (specifically, its housing 2821) is formed with a hole 2821b through which the cable 2920 passes. The hole 208a is formed in a position that overlaps the gripping portion 2820 in a plan view of the contact surface 206a of the diaphragm 206 when the chestpiece 2810 is in the home position. This allows the cable 2920 passing through the hole 208a to be hidden by the gripping portion 2820, thereby reducing the risk of the cable 2920 being damaged by external influences from the electronic auscultation device 2800. As shown in FIG. 28C , the hole 208a is formed in a position different from the connecting member 2811. However, the hole 208a may be positioned so that it passes through the connecting member 2811. The hole 2821b is formed on the surface facing the chestpiece 2810 when the chestpiece 2810 is in the home position. This allows the length of the cable 2920 to be shortened. It also reduces the risk of the cable 2920 being damaged by external influences from the electronic stethoscope device 2800. The gripping portion 2820 does not necessarily have to have the hole 2821b. In this case, the gripping portion 2820 may have a connector that connects the inside and outside of the housing 2821. The part of this connector inside the housing 2821 may be connected to the main circuit board 2910, and the part of this connector outside the housing 2821 may be connected to the cable 2920. Similarly, the chestpiece 2810 may also have a connector instead of the hole 208a.

[0316] [Wire of the Electronic Auscultation Device in the Third Embodiment] Next, the wire 2920 will be described in more detail with reference to Fig. 29C and Fig. 29D. Fig. 29C is a diagram focusing on the portion of Fig. 29A including the wire 2920. Fig. 29D is a diagram focusing on the portion of Fig. 29B including the wire 2920.

[0317] The following describes the sum of the distance between connector 2921 of chestpiece 2810 and hole 2821b of gripping portion 2820 and the distance between connector 2922 of gripping portion 2820 and hole 2821b of gripping portion 2820. The distance between the connector and the hole may be the distance between the center of the connector and the center of the hole, the distance between the part of the connector closest to the hole and the part of the hole closest to the connector, or a distance measured in some other way.

[0318] The sum of these distances changes as chestpiece 2810 pivots relative to gripping portion 2820. Because cable 2920 passes through hole 2821b in gripping portion 2820, the length of cable 2920 is greater than the maximum value of the sum of these distances within the range in which chestpiece 2810 can pivot.

[0319] 29C , when chestpiece 2810 is in the home position, L1 is the distance between connector 2921 of chestpiece 2810 and hole 2821b of gripping portion 2820, and L2 is the distance between connector 2922 of gripping portion 2820 and hole 2821b of gripping portion 2820. As shown in FIG. 29D , when chestpiece 2810 is in the inverted position, L3 is the distance between connector 2921 of chestpiece 2810 and hole 2821b of gripping portion 2820, and L4 is the distance between connector 2922 of gripping portion 2820 and hole 2821b of gripping portion 2820. Furthermore, the distance between connector 2921 of chestpiece 2810 and the center of pivot shaft 2811b is defined as L5, and the distance between connector 2922 of gripping portion 2820 and the center of pivot shaft 2811b is defined as L6. L5 and L6 are constant regardless of the position of chestpiece 2810 relative to gripping portion 2820.

[0320] The sum of the above-mentioned distances increases as the connector 2921 of the chestpiece 2810 moves farther away from the hole 2821b of the grip portion 2820. Therefore, L3 + L4 > L1 + L2 holds. The sum of the above-mentioned distances may be greatest when the chestpiece 2810 is in an inverted position. Therefore, the length of the cable bundle 2920 is greater than L3 + L4. Furthermore, in this embodiment, L3 > L1 > L5 holds, and L6 > L2 = L4 holds.

[0321] When the chestpiece 2810 swings so as to reduce the sum of the above-described distances (for example, when the chestpiece 2810 rotates from the inverted position toward the home position), the required length of the cable 2920 becomes shorter, and thus a portion of the cable 2920 bends. The housing 2821 of the gripping part 2820 is provided with a housing having a space 2912 that houses the bent portion of the cable 2920. When the chestpiece 2810 is in the inverted position, the cable 2920 is not contained in this space 2912, and when the chestpiece 2810 is in the home position, a portion of the cable 2920 is contained in this space 2912. Providing this space 2912 in the housing 2821 of the gripping part 2820 prevents the cable 2920 from bending outside the housing 2821. This reduces the risk of the cable 2920 being pinched between the chestpiece 2810 and the gripping portion 2820 and breaking.

[0322] The electronic auscultation device 2800 of this embodiment includes a holding mechanism for holding the chestpiece 2810 in an inverted position. For example, this holding mechanism may be composed of a protrusion 2811c (FIG. 28B) provided on the rotation shaft 2811b of the connecting member 2811 and a rotation stopper 2821c (FIG. 28B) provided on the receiving portion 2821a of the gripping portion 2820.

[0323] [Details of the Holding Mechanism of the Chestpiece of the Electronic Auscultation Device in the Third Embodiment] The holding mechanism for holding the chestpiece 2810 in an inverted position will be described in further detail with reference to Fig. 30. Each view in Fig. 30 is a part of a cross-sectional view of the electronic auscultation device 2800 in a plane parallel to the xz plane.

[0324] In the top diagram of FIG. 30 , the chestpiece 2810 is in the home position. As the chestpiece 2810 rotates relative to the grip 2820 toward the inverted position, the protrusion 2811c approaches the rotation stop 2821c, as shown in the middle diagram of FIG. 30 . The protrusion 2811c and the rotation stop 2821c are configured so that the protrusion 2811c overcomes the rotation stop 2821c when a torque equal to or greater than a threshold is applied to the chestpiece 2810. For example, this torque threshold may be a value greater than the torque generated by the weight of the chestpiece 2810, e.g., approximately 0.5 [N·m]. When the protrusion 2811c overcomes the rotation stop 2821c, the chestpiece 2810 is in the inverted position.

[0325] When the chestpiece 2810 is in the inverted position, the protrusion 2811c and the rotation stop 2821c maintain the chestpiece 2810 in the inverted position unless a torque equal to or greater than the threshold value is applied to the chestpiece 2810. When the contact surface 206a of the diaphragm 206 is placed on a horizontal surface (e.g., a tabletop) with the chestpiece 2810 maintained in the inverted position, the electronic auscultation device 2800 can stand on its own. This allows the user to temporarily stop using the electronic auscultation device 2800 by placing the contact surface 206a of the diaphragm 206 on a table while the contact surface 206a is protected (e.g., by the tabletop). Furthermore, maintaining the chestpiece 2810 in the inverted position facilitates storage and stowage of the electronic auscultation device 2800 after use.

[0326] [Modification of the electronic auscultation device in the third embodiment] With reference to Figures 31A to 31C, a modification of the electronic auscultation device 2800 will be described. Figure 31A shows a perspective view of the electronic auscultation device 2800 according to the modification, and Figures 31B to 31C are perspective views of a portion of the modification seen from a different angle.

[0327] In this modification, the chestpiece 2810 has a protrusion 3100 instead of the pivot shaft 2811b, and the grip portion 2820 has a receiving portion 3101 instead of the receiving portion 2821a. The protrusion 3100 has a spherical surface. Specifically, the housing 2821 of the grip portion 2820 has two receiving portions 3101. One receiving portion 3101 supports a portion of the spherical surface of the protrusion 3100, and the other receiving portion 3101 supports another portion of the spherical surface of the protrusion 3100. As a result, the two receiving portions 3101 uniformly contact and engage with the spherical surface of the protrusion 3100.

[0328] The spherical surface of the convex portion 3100 slides in the receiving portion 3101, allowing the chestpiece 2810 to rotate in multiple axial directions relative to the gripping portion 2820. Specifically, the chestpiece 2810 is rotatable along the xz plane, similar to the electronic auscultation device 2800 described in Figures 28A to 28D, and is also rotatable along the yz plane as shown in Figure 31C. This configuration allows the contact surface 206a of the diaphragm 206 to more easily come into close contact with the surface of a living body when the electronic auscultation device 2800 is in use.

[0329] Fourth Embodiment [Configuration Example of an Electronic Auscultation Device in the Fourth Embodiment] An example configuration of an electronic auscultation device 3200 according to the fourth embodiment will be described with reference to Figures 32A to 33D. Electronic auscultation devices may require replacement due to aging of the diaphragm or wear on the contact surface. However, if the diaphragm is the only replaceable part, there is a risk that the user may touch the optical sensor during replacement, or that the positional relationship between the diaphragm and the optical sensor may change. In such cases, measurement accuracy is affected by the characteristics of the diaphragm and the precision and optical characteristics of the components that attach the optical sensor. Therefore, one of the features of the electronic auscultation device according to the fourth embodiment is that it includes a base unit and a replacement unit, and is equipped with a detachment mechanism that allows the replacement unit, including the diaphragm, to be easily attached and detached from the base unit. The following description will mainly focus on the differences from the electronic auscultation device 2800 according to the third embodiment, and will omit a description of the similarities between the electronic auscultation device 2800 and the electronic auscultation device 2800. The differences between the third and fourth embodiments can be applied to the first or second embodiment. The appearance of the electronic auscultation device 3200 is similar to that of the electronic auscultation device 100 described with reference to Figures 1A and 1B. The modifications described in the first to third embodiments can also be applied to the fourth embodiment.

[0330] Electronic auscultation device 3200 includes a chestpiece 3210 and a gripping portion 2820. Chestpiece 3210 is similar to chestpiece 2810 of electronic auscultation device 2800, and gripping portion 2820 is similar to gripping portion 2820 of electronic auscultation device 2800, except for the differences described below.

[0331] FIG. 32A is a cross-sectional view of the electronic stethoscope device 2800 taken along a plane parallel to the xz plane. FIG. 32B is a perspective view of the chestpiece 3210. FIG. 32C is a view of the cross-sectional view of FIG. 32A focusing on the chestpiece 3210. FIG. 32D is a schematic view illustrating a user operation for removing the replacement unit 3230 from the base unit 3220. FIG. 33A is a perspective view of a portion of the base unit 3220 (a portion included in the chestpiece 3210). FIG. 33B is a view of the cross-sectional view of FIG. 32A focusing on a portion of the base unit 3220 (a portion included in the chestpiece 3210). FIG. 33C is a perspective view of the replacement unit 3230. FIG. 33D is a view of the cross-sectional view of FIG. 32A focusing on the replacement unit 3230.

[0332] As shown in FIG. 32D , the electronic auscultation device 3200 includes a base unit 3220 and a replacement unit 3230. The base unit 3220 is a component that is not expected to be replaced by a user during the product life of the electronic auscultation device 3200. The base unit 3220 includes a grip portion 2820 and a portion of the chestpiece 3210. However, replacement of the components of the base unit 3220 is not necessarily expected; some components of the base unit 3220 can be replaced through repairs at the factory, for example. The battery 2911 of the grip portion 2820 can be replaced by the user.

[0333] The replacement unit 3230 is a part that is expected to be replaced by a user during the product life of the electronic auscultation device 3200. In the electronic auscultation device 3200, the replacement unit 3230 is coupled to the base unit 3220 so that the replacement unit 3230 can be attached and detached by a user operation. The electronic auscultation device 3200 has a detachment mechanism that couples the replacement unit 3230 to the base unit 3220 so that the replacement unit 3230 can be attached and detached by a user operation. Hereinafter, such a detachment mechanism will be referred to as the detachment mechanism of the electronic auscultation device 3200, or simply as the detachment mechanism.

[0334] The chestpiece 3210 differs from the chestpiece 2810 of the third embodiment in that it includes a relay circuit board 3231, a connector 3232, a lock pin 3233, a relay circuit board 3221, a connector 3222, and a connector 3223.

[0335] The relay circuit board 3231 is connected to the holding member 201 (for example, the upper holding member 1106 thereof). In the electronic stethoscope device 3200, this connection is made by fasteners such as screws.

[0336] The relay circuit board 3231 is connected to the light-emitting circuit board 203 by a lead wire (not shown). The relay circuit board 3231 transmits a control signal to the light-emitting circuit board 203 to instruct it to emit light and supplies power through this lead wire. The relay circuit board 3231 is also connected to the light-receiving circuit board 205 by a lead wire (not shown). The relay circuit board 3231 receives a displacement signal from the light-receiving circuit board 205 through this lead wire and supplies power to the light-receiving circuit board 205. The relay circuit board 3231 is also connected to the microphone 1101 by a lead wire (not shown). The relay circuit board 3231 receives an audio signal from the microphone 1101 through this lead wire and supplies power to the microphone 1101.

[0337] The relay circuit board 3221 is connected to the inner surface of the housing 208. In the electronic auscultation device 3200, this connection is made with screws.

[0338] A connector 3232 is mounted on the upper surface of the relay circuit board 3231, and connectors 3222 and 3223 are mounted on the lower surface of the relay circuit board 3221. The connectors 3222 and 3223 are electrically connected to each other by a conductive pattern formed on the relay circuit board 3221. The connector 3223 of the relay circuit board 3221 is connected to a connector 2921 of a cable 2920 extending through a hole 208a in the housing 208. The connector 3222 of the relay circuit board 3221 is connected to a connector 3232 of the relay circuit board 3231. As a result, a signal from the relay circuit board 3231 is transmitted to the main circuit board 2910 through the connector 3232, the connector 3222, the connector 3223, and the cable 2920. Furthermore, power is supplied from the main circuit board 2910 to the relay circuit board 3231 through the connector 3232 , the connector 3222 , the connector 3223 , and the cable 2920 .

[0339] Of the components of the chestpiece 3210, 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, the diaphragm 206, the light reflecting portion 207, the relay circuit board 3231, and the connector 3232 are included in the replacement unit 3230. Of the components of the chestpiece 3210, the housing 208, the connecting member 2811, the relay circuit board 3221, the connector 3222, and the connector 3223 are included in the base unit 3220. Therefore, in the electronic stethoscope device 3200, not only the diaphragm 206 is replaced, but the components that make up the displacement detection unit 1011 (i.e., the light-emitting element 202, the light-receiving element 204, and the light reflecting portion 207) are replaced together with the diaphragm 206.

[0340] In this embodiment, the light reflecting portion 207 is attached to the diaphragm 206. Therefore, when the diaphragm 206 is removed from the holding member 201 by a user operation and replaced with another diaphragm 206, the positional relationship between the light emitting element 202 and the light reflecting portion 207 or the positional relationship between the light receiving element 204 and the light reflecting portion 207 may change. If these positional relationships change, it may become impossible to accurately detect displacement of the biological surface. Therefore, in this embodiment, by including the components constituting the displacement detection portion 1011 and the diaphragm 206 in the replacement unit 3230, it becomes possible to replace the diaphragm 206 without reducing the accuracy of detecting displacement of the biological surface.

[0341] As described above, the holding member 201 holds the light-emitting element 202, the light-receiving element 204, and the diaphragm 206 in a predetermined positional relationship. The replacement unit 3230 can be attached to and detached from the base unit 3220 by a user operation while the holding member 201 holds the light-emitting element 202, the light-receiving element 204, and the diaphragm 206 in this positional relationship. This prevents a decrease in the accuracy of detecting displacement of the biological surface due to a shift in their positional relationship. Furthermore, the replacement unit 3230 can be attached to and detached from the base unit 3220 while maintaining the internal space 213 facing the inner surface 206b of the diaphragm 206. In other words, the light-reflecting unit 207, the light-emitting element 202, and the light-receiving element can be prevented from being touched by the user when replacing the units. This prevents a decrease in the accuracy of detecting displacement of the biological surface due to contamination of the light-reflecting unit 207, the light-emitting element 202, and the light-receiving element 204 caused by user operation.

[0342] In the above-described embodiment, the connector 2913 of the main circuit board 2910 included in the gripping portion 2820 is electrically connected to the connector 3223 of the relay circuit board 3221 coupled to the housing 208 by the cable 2920. Furthermore, the connector 3222 of the relay circuit board 3221 included in the base unit 3220 and the relay circuit board 3231 included in the replacement unit 3230 are electrically connected by coupling the base unit 3220 and the replacement unit 3230 by a detachable mechanism. This configuration allows the chestpiece 3210 to swing relative to the gripping portion 2820, while also enabling the replacement unit 3230, including the displacement detection unit 1011 and the diaphragm 206, to be attached and detached. In other words, the electronic auscultation device 3200 achieves both improved user operability and ease of replacement of the replacement unit 3230.

[0343] When the chestpiece 3210 includes the microphone 1101 and the seal member 1102 as in the third embodiment, these components are also included in the replacement unit 3230. This makes it possible for the user to replace the replacement unit 3230 while maintaining the internal space 213 of the chestpiece 3210 as an airtight space.

[0344] 32C, the shapes of the holding member 201 and the housing 208 will be described in more detail. The holding member 201 includes a sidewall 1104e that extends along the outer periphery of the diaphragm 206. In the electronic auscultation device 3200 of this embodiment, the base holding member 1104 has the sidewall 1104e.

[0345] As shown in FIG. 32D , the housing 208 has a cylindrical portion 208b and a top plate portion 208c. The top plate portion 208c is connected to the entire periphery of the upper end of the cylindrical portion 208b and is a curved portion molded integrally with the cylindrical portion 208b. The center of the top plate portion 208c protrudes upward, and a coupling member 2811 is coupled to this protruding portion. The coupling member 2811 is coupled to the housing 208 in a manner that does not anticipate removal by user operation. The housing 208 is coupled to a grip portion 2820 via the coupling member 2811 in a manner that allows it to swing.

[0346] When the replacement unit 3230 is coupled to the base unit 3220, the cylindrical portion 208b is located outside the side wall 1104e and surrounds the periphery of the side wall 1104e. The outer diameter of the side wall 1104e and the inner diameter of the cylindrical portion 208b are approximately equal. The lower end of the cylindrical portion 208b of the housing 208 contacts the holding member 201. When the housing 208 is coupled to the holding member 201, the housing 208 covers the components held by the holding member 201, namely, the light-emitting circuit board 203 on which the light-emitting element 202 is formed, the light-receiving circuit board 205 on which the light-receiving element 204 is formed, and the relay circuit board 3231 on which the connector 3232 is mounted.

[0347] [Attachment / Detachment Mechanism of Electronic Auscultation Device in Fourth Embodiment] Next, the attachment / detachment mechanism of the electronic auscultation device 3200 will be described with reference to Figures 32A to 32D. The attachment / detachment mechanism of the electronic auscultation device 3200 is composed of a lock pin 3233 and a hole 208d formed in the housing 208. A hole for passing the lock pin 3233 is formed in the side wall 1104e. The side wall 1104e supports the lock pin 3233 so that the lock pin 3233 can move in the longitudinal direction of the lock pin 3233.

[0348] When the replacement unit 3230 is coupled to the base unit 3220, the lock pin 3233 passes through both the hole in the side wall 1104e and the hole 208d in the housing 208, with its tip protruding from the housing 208. The lock pin 3233 is biased toward the outside of the chestpiece 3210 by a biasing member such as a spring. Therefore, unless an external force is applied, the lock pin 3233 maintains a state in which its tip protrudes from the housing 208. The base side of the lock pin 3233 is thicker than the hole in the side wall 1104e to prevent it from falling out of the chestpiece 3210.

[0349] The lock pin 3233 has a spherical portion that forms the tip and a cylindrical portion that extends from the spherical portion. When no external force is applied to the lock pin 3233, the cylindrical portion of the lock pin 3233 is located inside the hole 208d in the side wall 1104e. As a result, unless an external force is applied to the lock pin 3233, the movable range of the replacement unit 3230 relative to the base unit 3220 is limited to the gap between the lock pin 3233 and the housing 208. In other words, movement of the replacement unit 3230 relative to the base unit 3220 is locked by the lock pin 3233.

[0350] On the other hand, when the lock pin 3233 is pushed inward by a user operation, the spherical portion of the lock pin 3233 is positioned inside the hole 208d in the side wall 1104e. In this state, when the replacement unit 3230 is pulled upward in the z-axis direction relative to the base unit 3220, the side wall 1104e pushes the lock pin 3233 further inward, making it possible to move the replacement unit 3230 to remove it from the base unit 3220. In other words, the lock by the lock pin 3233 preventing movement of the replacement unit 3230 relative to the base unit 3220 is released.

[0351] As shown in Figures 33A and 33B, the electronic auscultation device 3200 further includes a restriction mechanism that restricts the movement path of the replacement unit 3230 relative to the base unit 3220. In the electronic auscultation device 3200, the restriction mechanism is formed by a protrusion 208e provided on the inner surface of the cylindrical portion 208b of the housing 208 and a slit 1104f provided in the side wall 1104e of the holding member 201. The protrusion 208e and the slit 1104f restrict the movement path of the replacement unit 3230 relative to the base unit 3220 to movement in the normal direction of the contact surface 206a of the diaphragm 206. This ensures that the connectors 3222 and 3232 are coupled at the correct angle. While the protrusion 208e is rectangular in shape in the example shown in Figure 33A, it may have other shapes, such as a cube, that can pass through the slit 1104f. In the example shown in FIG. 33C, the slit 1104f penetrates the side wall 1104e, but it may also be configured to form a recess in the side wall 1104e.

[0352] 32D , a user operation for attaching or detaching the replacement unit 3230 to or from the base unit 3220 will be described. To detach the replacement unit 3230 from the base unit 3220, the user moves the replacement unit 3230 in the z-axis direction away from the base unit 3220 while pressing the lock pin 3233. As described above, by pushing in the lock pin 3233, the lock on the movement of the replacement unit 3230 relative to the base unit 3220 is released. In this state, the replacement unit 3230 is detached from the base unit 3220 by moving the replacement unit 3230 relative to the base unit 3220 so that the convex portion 208e moves along the slit 1104f. This user operation disconnects the connector 3232 on the replacement unit 3230 side from the connector 3222 on the base unit 3220 side (see Figures 32C, 33A, and 33B), and the electrical contacts of the connector 3222 and the electrical contacts of the connector 3232 are separated from each other.

[0353] On the other hand, when attaching the replacement unit 3230 to the base unit 3220, the user aligns the protrusion 208e with the slit 1104f, and then, while pressing the lock pin 3233, moves the replacement unit 3230 toward the base unit 3220 in the z-axis direction. When the replacement unit 3230 is properly coupled to the base unit 3220, the lock pin 3233 protrudes from the hole 208d, locking the movement of the replacement unit 3230 relative to the base unit 3220. This user operation couples the connector 3222 on the base unit 3220 with the connector 3232 on the replacement unit 3230, and the electrical contacts of the connector 3222 and the connector 3232 come into contact with each other. Because the connector 3232 included in the replacement unit 3230 is located outside the internal space 213, the connector 3232 is coupled to the connector 3222 while maintaining the airtightness of the internal space 213.

[0354] The electronic auscultation device 3200 includes two lock pins 3233. The number of lock pins 3233 does not have to be two, and may be one, or three or more. However, two or fewer lock pins 3233 may be included to make it easier for a user to operate the lock pin 3233 with their fingertips. In the electronic auscultation device 3200, the lock pin 3233 is included in the replacement unit 3230, and the hole 208d that engages with the lock pin 3233 is included in the base unit 3220. Alternatively, the lock pin may be included in the base unit 3220, and the hole that engages with the lock pin may be included in the replacement unit 3230. In the electronic auscultation device 3200, the chestpiece 3210 is pivotally coupled to the grip portion 2820. Alternatively, the chestpiece 3210 may be non-pivotally coupled to the grip portion 2820. The electronic auscultation device 3200 does not have to include the grip portion 2820, and may be configured with the chestpiece 3210 alone. In this case, too, the chestpiece 3210 may be separated into a base unit and a replacement unit. The attachment / detachment mechanism using the lock pin 3233 allows attachment / detachment without the need for a tool such as a screwdriver. Alternatively, the operation of attaching / detaching the replacement unit 3230 to / from the base unit 3220 may include an operation using a tool, such as unscrewing a screwdriver.

[0355] After the replacement unit 3230 is removed from the base unit 3220, the same replacement unit 3230 may be attached to the base unit 3220, or a different replacement unit 3230 may be attached to the base unit 3220. The positional relationship between the light reflecting portion 207, the light emitting element 202, and the light receiving element 204 in the replacement unit 3230 varies from replacement unit 3230 to replacement unit 3230 due to manufacturing errors, etc. Therefore, parameters determined by this positional relationship have values ​​unique to each replacement unit 3230. Such parameters may include the amount of light reaching the light receiving element 204 when the diaphragm 206 is not pressed, and the amount of change in the amount of light reaching the light receiving element 204 per unit displacement of the diaphragm 206. Therefore, the replacement unit 3230 may further include a memory 3234 that stores parameters determined by the positional relationship between the light reflecting portion 207, the light emitting element 202, and the light receiving element 204. The memory 3234 may be mounted, for example, on the relay circuit board 3231. After the replacement unit 3230 is attached to the base unit 3220, the sound output unit 1020 mounted on the main circuit board 2910 included in the base unit 3220 may read the parameters in the memory 3234 and adjust the generation of a signal according to the parameters.

[0356] [Modification of the Attachment / Detachment Mechanism of the Electronic Auscultation Device in the Fourth Embodiment] Modifications of the attachment / detachment mechanism of the electronic auscultation device 3200 of the fourth embodiment will be described with reference to Figures 34A to 35D. Each of Figures 34A to 35D corresponds to each of Figures 32A to 33D. The electronic auscultation device 3400 differs from the electronic auscultation device 3200 in that it has a chestpiece 3410 instead of the chestpiece 3210. The electronic auscultation device 3400 also differs from the electronic auscultation device 3200 in that it has a base unit 3420 and a replacement unit 3430 instead of the base unit 3220 and replacement unit 3230. In other respects, it is similar to the electronic auscultation device 3200.

[0357] The electronic auscultation device 3400 has connectors 3422 and 3432 instead of connectors 3222 and 3232. Connector 3432 is mounted on the upper surface of relay circuit board 3231. Connector 3422 is mounted on the lower surface of relay circuit board 3221. Connectors 3422 and 3223 are electrically connected to each other by a conductive pattern formed on relay circuit board 3221. Connector 3422 includes a plurality of electrical contacts, each of which is partially exposed on the lower surface of connector 3422. Connector 3432 includes a plurality of electrical contacts, each of which is partially exposed on the upper surface of connector 3432.

[0358] Furthermore, the shapes of the protrusion 208e and the slit 1104f in the electronic auscultation device 3400 differ from those in the above-described electronic auscultation device 3200. The slit 1104f is L-shaped. Specifically, the slit 1104f includes a vertical portion extending from the upper end of the side wall 1104e in the normal direction to the contact surface 206a of the diaphragm 206, and a horizontal portion extending from the lower end of this vertical portion along the outer periphery of the diaphragm 206. The protrusion 208e may be cubic as shown in the figure, or may have another shape that can pass through the slit 1104f.

[0359] 34D , a user operation for attaching or detaching the replacement unit 3430 to or from the base unit 3420 will be described. The user operation for detaching the replacement unit 3430 from the base unit 3420 includes rotating the replacement unit 3430 relative to the base unit 3420 while pressing the lock pin 3233, and then moving the replacement unit 3430 away from the base unit 3420. As described above, the lock on the movement of the replacement unit 3430 relative to the base unit 3420 is released by pushing the lock pin 3233. In this state, the replacement unit 3430 is detached from the base unit 3420 by moving the replacement unit 3430 relative to the base unit 3420 so that the convex portion 208e moves along the slit 1104f. This user operation causes the electrical contacts of the connector 3422 and the electrical contacts of the connector 3432 to separate from each other.

[0360] A user operation for attaching the replacement unit 3430 to the base unit 3420 includes aligning the protrusion 208e with the slit 1104f, then moving the replacement unit 3430 in a direction approaching the base unit 3420 while pressing the lock pin 3233, and then rotating the replacement unit 3430 relative to the base unit 3420. When the replacement unit 3430 is properly coupled to the base unit 3420, the lock pin 3233 protrudes from the hole 208d, locking the movement of the replacement unit 3430 relative to the base unit 3420. This user operation brings the electrical contacts of the connector 3422 and the connector 3432 into contact with each other. Because the connector 3432 included in the replacement unit 3430 is located outside the internal space 233, the connector 3432 is coupled to the connector 3422 while maintaining the internal space 233.

[0361] The restriction mechanism that restricts the movement path of the replacement unit 3230 relative to the base unit 3220 may be configured in other ways. For example, the restriction mechanism may be configured by a screw thread provided on the inner surface of the cylindrical portion 208b of the housing 208 and a screw groove provided on the outer surface of the side wall 1104e. In ...

Claims

1. A diaphragm that contacts an object to be measured, wherein a light-reflecting portion is provided on the surface of the diaphragm opposite to the contact surface that contacts the object to be measured, Light-emitting diodes and A diaphragm that narrows the light emitted from the light-emitting diode, A light-receiving element having a light-receiving surface that receives light that has passed through the aperture and been specularly reflected by the light-reflecting portion, An output means that outputs a signal corresponding to the light in the light-irradiated area formed by specularly reflected light that reaches the light-receiving surface, A housing that houses the light-emitting diode, the aperture, and the light-receiving element inside, An electronic device equipped with, The diaphragm, together with the housing, forms part of the exterior of the electronic device and is configured to elastically deform upon pressure from the object to be measured that comes into contact with the contact surface. An electronic device characterized in that the boundary line between the light-irradiated area and the area other than the light-irradiated area on the light-receiving surface, which is formed by light that is narrowed by the aperture and specularly reflected by the light-reflecting portion, moves in accordance with the displacement of the contact surface due to the elastic deformation of the diaphragm, thereby changing the area of ​​the light-irradiated area on the light-receiving surface and changing the output of the output means.

2. The electronic device according to claim 1, characterized in that when the amount of displacement of the contact surface increases, the area of ​​the light irradiation region on the light receiving surface decreases.

3. The electronic device according to claim 1, characterized in that the area of ​​the light irradiation region on the light receiving surface increases as the amount of displacement of the contact surface increases.

4. The electronic device according to claim 1, characterized in that the area of ​​the light irradiation region is defined by the boundary line, a first line segment that does not move in accordance with the displacement of the contact surface and whose length does not change even if the contact surface is displaced, and a second line segment that does not move in accordance with the displacement of the contact surface and whose length changes when the contact surface is displaced.

5. When the aperture portion is designated as the first aperture portion, a second aperture portion is provided for narrowing the light that has been specularly reflected by the light reflecting portion. The electronic device according to claim 4, characterized in that the first line segment is a line segment formed by light focused by the second aperture.

6. The electronic device according to claim 4, characterized in that the first line segment is a line segment that forms the edge of the light-receiving region of the light-receiving element.

7. The electronic device according to claim 1, characterized in that it is a device for measuring the vibration of the object to be measured.

8. The electronic device according to claim 1, further comprising a transmitting means for transmitting an audio signal corresponding to the output of the output means to an external audio output device.

9. The aforementioned electronic device is A chestpiece for measuring the vibration of the object to be measured, including the aforementioned housing, A gripping portion attached to the chestpiece, which is grasped by the user, The electronic device according to claim 6, characterized by comprising:

10. The electronic device according to claim 9, characterized in that the gripping portion includes a display unit for displaying the status of the electronic device.

11. The electronic device according to claim 9, characterized in that the gripping portion includes an operating portion for receiving settings of the electronic device.

12. The electronic device according to claim 1, characterized in that the light-reflecting portion is provided on the surface opposite to the contact surface, in a portion of the area including the center of the circle of the diaphragm.

13. The electronic device according to claim 1, characterized in that when the angle of incidence of light incident on the surface of the light reflecting portion is θ, the relationship 45° < θ < 90° is satisfied.

14. The electronic device according to claim 1, characterized in that the light-reflecting portion is a sheet-like member attached to the surface of the diaphragm opposite to the contact surface.

15. The electronic device according to claim 1, characterized in that the housing is made of a metal material and the surface density of the housing is greater than the surface density of the diaphragm.

16. A diaphragm that contacts an object to be measured, wherein a light-reflecting portion is provided on the surface of the diaphragm opposite to the contact surface that contacts the object to be measured, Light-emitting diodes and A diaphragm that narrows the light emitted from the light-emitting diode, A light-receiving element having a light-receiving surface that receives light that has passed through the aperture and been specularly reflected by the light-reflecting portion, An output means that outputs a signal corresponding to the light that reaches the light-receiving surface, A housing that houses the light-emitting diode, the aperture, and the light-receiving element inside, An electronic device equipped with, The electronic device is characterized in that the diaphragm, together with the housing, forms part of the exterior of the electronic device and is configured to elastically deform upon pressure from an object to be measured that comes into contact with the contact surface.

17. The electronic device according to claim 16, characterized in that when the amount of displacement of the contact surface increases, the area of ​​the light-irradiated region formed by specularly reflected light that reaches the light-receiving surface decreases.

18. The electronic device according to claim 16, characterized in that when the amount of displacement of the contact surface increases, the area of ​​the light-irradiated region formed by specularly reflected light that reaches the light-receiving surface increases.

19. The electronic device according to claim 16, characterized in that the area of ​​the light-irradiated region formed by specularly reflected light reaching the light-receiving surface is defined by a boundary line between the light-irradiated region and a region other than the light-irradiated region on the light-receiving surface, which is a boundary line formed by light that is narrowed by the aperture and specularly reflected by the light-reflecting portion, a first line segment that does not move in accordance with the displacement of the contact surface and whose length does not change even if the contact surface is displaced, and a second line segment that does not move in accordance with the displacement of the contact surface and whose length changes when the contact surface is displaced.

20. When the aperture portion is a first aperture portion, the device further comprises a second aperture portion that narrows the light specularly reflected by the light reflecting portion, The electronic device according to claim 19, characterized in that the first line segment is a line segment formed by light focused by the second aperture.

21. The electronic device according to claim 19, characterized in that the first line segment is a line segment that forms the edge of the light-receiving region of the light-receiving element.

22. The electronic device according to claim 16, characterized in that the electronic device is a device for measuring the vibration of the object to be measured.

23. The electronic device according to claim 16, further comprising a transmitting means for transmitting an audio signal corresponding to the output of the output means to an external audio output device.

24. The electronic device is A chestpiece for measuring the vibration of the object to be measured, including the aforementioned housing, A gripping portion attached to the chestpiece, which is grasped by the user, The electronic device according to claim 21, characterized by comprising:

25. The electronic device according to claim 24, characterized in that the gripping portion is provided with a display unit for displaying the status of the electronic device.

26. The electronic device according to claim 24, characterized in that the gripping portion includes an operating portion for receiving settings of the electronic device.

27. ​​The electronic device according to claim 16, characterized in that the light reflecting portion is provided on the surface opposite to the contact surface, in a portion of the area including the center of the circle of the diaphragm.

28. The electronic device according to claim 16, characterized in that when the angle of incidence of light incident on the surface of the light reflecting part is θ, the relationship 45° < θ < 90° is satisfied.

29. The electronic device according to claim 16, characterized in that the light reflecting portion is a sheet-like member attached to the surface of the diaphragm opposite to the contact surface.

30. The electronic device according to claim 16, wherein the housing is made of a metal material and the surface density of the housing is greater than the surface density of the diaphragm.