Detection device and electronic auscultation device

Abstract

To provide an electronic stethoscope that suppresses the influence of optical properties. [Solution] A detection device for detecting vibrations of a target to be detected, comprising: a diaphragm having a reflective surface that moves in accordance with the vibrations of the target to be detected; a light-emitting unit that emits light toward the reflective surface; a light-receiving unit that receives the light reflected by the reflective surface and outputs a signal corresponding to the light; an aperture unit that narrows the light emitted by the light-emitting unit before it reaches the light-receiving unit; a calibration execution means that performs at least one of the following as calibration: correction of the light intensity of the light-emitting unit and correction of the light-receiving sensitivity of the light-receiving unit; and a control unit that starts a calibration processing flow for performing calibration when predetermined execution conditions are met.

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a detection device and an electronic stethoscope including the detection device.

Background Art

[0002] In recent years, electronic stethoscopes having sensors for measuring biological vibrations and capable of acquiring biological sounds by the sensors have begun to spread. Patent Document 1 discloses a device for measuring biological signals using an optical element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An electronic stethoscope using an optical element needs to precisely arrange a light emitting element, a light receiving element, and further a diaphragm film in order to detect minute vibrations of a living body. However, assembly tolerances in the manufacture of parts related to optical characteristics, component characteristic tolerances of the light emitting element and the light receiving element, and further changes in the amount of light due to the durability of the light emitting element have a great influence on the optical characteristics.

[0005] The present invention provides an electronic stethoscope that suppresses the influence of optical characteristics.

Means for Solving the Problems

[0006] The detection device of the present invention is a detection device that detects vibrations of a detection target, a diaphragm having a reflecting surface that moves in response to the vibrations of the detection target, a light emitting unit that emits light toward the reflecting surface, a light receiving unit that receives the light reflected by the reflecting surface and outputs a signal corresponding to the light A diaphragm unit that narrows the light emitted by the light-emitting unit before it reaches the light-receiving unit, Calibration execution means for performing at least one of the following as calibration: correction of the light intensity of the light-emitting part and correction of the light-receiving sensitivity of the light-receiving part. A control unit that starts a calibration process flow for performing the calibration when predetermined execution conditions are met, It is characterized by being equipped with [the following features].

[0007] According to the present invention, an electronic stethoscope can be provided that suppresses the influence of optical properties. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a schematic diagram illustrating an example of the external appearance of the electronic stethoscope according to the first embodiment. [Figure 1B] This is a schematic diagram illustrating an example of the external appearance of the electronic stethoscope according to the first embodiment. [Figure 2] This is a schematic diagram illustrating an example of the configuration of the chestpiece according to the first embodiment. [Figure 3A] This is a schematic diagram illustrating an example of the operation of the chestpiece of the first embodiment. [Figure 3B] This is a schematic diagram illustrating an example of the operation of the chestpiece of the first embodiment. [Figure 3C] This is a schematic diagram illustrating an example of the operation of the chestpiece of the first embodiment. [Figure 3D] This is a schematic diagram illustrating an example of the operation of the chestpiece of the first embodiment. [Figure 3E] This is a schematic diagram illustrating an example of the change in the light-receiving range of the first embodiment. [Figure 4] This figure illustrates the relationship between the amount of displacement and the displacement signal in the first embodiment. [Figure 5] This figure illustrates an example of the hardware configuration of the electronic stethoscope according to the first embodiment. [Figure 6A] This is a cross-sectional view of the electronic stethoscope according to the first embodiment. [Figure 6B]It is a perspective view showing a part of the base unit of the first embodiment. [Figure 6C] It is a cross-sectional view showing a part of the base unit of the first embodiment. [Figure 6D] It is a perspective view of the replacement unit of the first embodiment. [Figure 6E] It is a cross-sectional view of the replacement unit of the first embodiment. [Figure 7] It is a diagram for explaining the attachment / detachment detection configuration of the first embodiment. [Figure 8] It is a diagram showing the state of the electronic stethoscope of the first embodiment. [Figure 9A] It is a diagram for explaining the variation of the displacement signal. [Figure 9B] It is a diagram for explaining the variation of the displacement signal. [Figure 10] It is a diagram for explaining Example 1 of the calibration processing flow of the first embodiment. [Figure 11] It is a diagram for explaining Example 2 of the calibration processing flow of the first embodiment. [Figure 12A] It is a diagram for explaining an example of the light quantity correction method. [Figure 12B] It is a diagram for explaining an example of the light quantity correction method. [Figure 13] It is a diagram for explaining Example 3 of the calibration processing flow of the first embodiment. [Figure 14] It is a diagram for explaining Example 4 of the calibration processing flow of the first embodiment.

Best Mode for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, the embodiments for carrying out this invention will be illustratively and in detail described based on examples. Note that the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment should be appropriately changed according to the configuration of the device to which the invention is applied and various conditions. That is, it is not intended to limit the scope of this invention to the following embodiments.

[0010] <First Embodiment> [Appearance of the electronic stethoscope in the first embodiment] The appearance of the electronic stethoscope 100 according to the first embodiment will be described with reference to Figures 1A and 1B. Note that the following drawings may include a coordinate system CS, a three-dimensional Cartesian coordinate system having x, y, and z axes, to indicate direction. In these descriptions, the positive z-axis direction may be referred to as the upper side, and the negative z-axis direction as the lower side. Figure 1A shows the appearance of the electronic stethoscope 100 viewed from one direction, and Figure 1B shows the appearance of the electronic stethoscope 100 viewed from another direction. The electronic stethoscope 100 is a diagnostic instrument for listening to internal sounds of living organisms such as humans or animals. The electronic stethoscope 100 is mainly used to listen to heart sounds and respiratory sounds.

[0011] As shown in Figure 1A, the electronic auscultation device 100 has a chestpiece 110 and a gripping part 120. The chestpiece 110 is a unit that, when used for diagnosis with the electronic auscultation device 100, is brought into contact with the surface of a living body, which is an example of a detection target (object to be measured, subject), to detect (measure) minute vibrations (displacements) of the living body's surface and capture living sounds. The chestpiece 110 functions as a detection device that detects minute displacements and vibrations of the living body's surface in close contact with it via a diaphragm 206, which will be described later.

[0012] The gripping portion 120 is gripped by the user of the electronic stethoscope 100 (for example, a doctor, nurse, or public health nurse) when bringing the diaphragm 206 into close contact with a biological surface. Hereinafter, the user of the electronic stethoscope 100 will simply be referred to as the user. The gripping portion 120 is rod-shaped, as shown in Figures 1A and 1B, and the chestpiece 110 is attached to one end (the negative x-axis direction in Figures 1A and 1B).

[0013] The gripping unit 120 has a housing 121. The gripping unit 120 houses a battery and a circuit board inside the housing 121. The battery stores the operating power of the electronic stethoscope 100. The circuit board has circuit elements for controlling the operation of the electronic stethoscope 100. The gripping unit 120 has a display unit 122, an operating 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 stethoscope 100. The display unit 122 may include multiple indicators. In this embodiment, as shown in Figure 1A, the display unit 122 includes four indicators. In this embodiment, the multiple indicators include an indicator that shows whether the electronic stethoscope 100 is powered on or off. The multiple indicators also include an indicator that shows the current operating mode of the electronic stethoscope 100. The multiple indicators also include an indicator that shows whether the electronic stethoscope 100 is wirelessly connected to an external device. The multiple indicators also include an indicator that shows whether the chestpiece 110 is pressed against a biological surface.

[0015] As shown in Figure 1A, the display unit 122 is positioned near the chestpiece 110 on one end of the outer surface of the housing 121, on the side opposite to the surface to which the chestpiece 110 is connected, in the x-axis direction. In this embodiment, "near the chestpiece 110" means closer to the chestpiece 110 than the center of the gripping portion 120. Note that the display unit 122 does not need to include all of the indicators described above, and the status of the electronic stethoscope 100 may be displayed by a liquid crystal panel or an electrostatic panel instead of or in addition to the multiple indicators.

[0016] The control unit 123 receives input from the user. The control unit 123 may include a number of physical buttons for receiving settings for the electronic stethoscope 100. In this embodiment, the control unit 123 includes four buttons as shown in Figure 1A. Specifically, the control unit 123 includes a volume up button 123a and a volume down button 123b as volume adjustment buttons for adjusting the volume of the output sound. When a volume adjustment button is pressed, the electronic stethoscope 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.

[0017] The control unit 123 also includes a mode switching button 123c for switching the operating mode of the electronic stethoscope 100. Pressing the mode switching button 123c switches the operating mode, as described later. In other words, the mode switching button 123c receives instructions from the user regarding the mode transition of the electronic stethoscope 100. Based on the instructions from the user using the mode switching button 123c, the electronic stethoscope 100 selects one of several operating modes and operates in that operating mode.

[0018] The operating unit 123 also includes a calibration button 123d for performing calibration of the electronic stethoscope 100. When the calibration button 123d is pressed, calibration is performed to maintain the accuracy of the output of the electronic stethoscope 100. In this embodiment, the calibration button 123d is positioned next to the mode switching button 123c in the x-axis direction, and is closer to the center of the gripping unit 120 than the mode switching button 123c. The calibration button 123d may be located away from the mode switching button 123c and the volume adjustment button. For example, the calibration button 123d may be positioned next to the power switch 124.

[0019] 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 as a touchscreen. The diagnostic device 100 may, instead of, or in addition to, instructions from the user using the mode switching button 123c, automatically select an operating mode in response to a signal representing vibrations of the biological surface that has been acquired.

[0020] The control unit 123, like the display unit 122, is located on the outer surface of the housing 121, on the side opposite to the chestpiece 110, near the chestpiece 110, at one end in the x-axis direction. This arrangement allows the user to operate the control unit 123 (for example, with their thumb) while holding the gripping unit 120 during use of the electronic stethoscope 100. The display unit 122 is positioned further away from the center of the gripping unit 120 in the x-axis direction than the control unit 123. This arrangement allows the user to maintain visibility of the display unit 122 even when operating the control unit 123 during use of the electronic stethoscope 100.

[0021] The power switch 124 is a switch that turns the power of the electronic stethoscope 100 on and off. The connector 125 is a connector for receiving a cable or connector of an external device. Power is supplied from the external device to the battery included in the gripping part 120 through the connector 125. The power switch 124 may be provided on the chestpiece 110 instead of on the gripping part 120. Also, if the display unit 122 and the operation unit 123 are configured as a single touchscreen, the power switch 124 may also be included in the touchscreen. The connector 125 may be provided on the chestpiece 110 instead of on the gripping part 120. Furthermore, the electronic stethoscope 100 does not have to include the connector 125. In this case, the electronic stethoscope 100 may have a wireless charging function or may be configured to have a replaceable battery.

[0022] [Chestpiece configuration of the electronic stethoscope in the first embodiment] Referring to Figure 2, an example of the configuration of the chestpiece 110 will be described. The upper part of Figure 2 shows a cross-sectional view of the chestpiece 110, and the lower part of Figure 2 shows a plan view of the chestpiece 110. In the plan view, only the light-emitting circuit board 203, light-receiving circuit board 205, diaphragm 206, and light-reflecting part 207 are shown to clarify the positional relationship of the components.

[0023] The chestpiece 110 includes a holding member 201, a light-emitting element 202, a light-emitting circuit board 203, a light-receiving element 204, a light-receiving circuit board 205, a diaphragm 206, a light-reflecting part 207, and a housing 208. The housing 208 houses the holding member 201, the light-emitting element 202, the light-emitting circuit board 203, the light-receiving element 204, the light-receiving circuit board 205, and the light-reflecting part 207. The holding member 201 has aperture sections 209 and 210 formed thereon. Therefore, the housing 208 also houses the aperture sections 209 and 210. The diaphragm 206, together with the housing 208, forms part of the exterior of the electronic stethoscope 100.

[0024] The light-emitting element 202 is a light source that emits light. The power supplied to the light-emitting element 202 is supplied from an external power source (the battery of the gripping part 120) of the chestpiece 110. In this embodiment, the light-emitting element 202 uses a light-emitting diode (LED).

[0025] The light-emitting element 202 is mounted on the light-emitting circuit board 203. The light-emitting circuit board 203 is equipped with, for example, peripheral circuits for defining the amount of light emitted by the light-emitting element 202, and power terminals for receiving power from an external power source of the chestpiece 110. The light-emitting circuit board 203 may be a printed circuit board such as a flexible circuit board, or it may be a paper phenolic substrate or a glass epoxy substrate. The light-emitting circuit board 203 including the light-emitting element 202 functions as a light-emitting unit.

[0026] The light-receiving element 204 is a light sensor that uses power supplied from an external power source (the battery of the gripping part 120) of the chestpiece 110 to generate an electrical signal based on the amount of light it receives. It functions. The power supplied to the light-receiving element 204 is supplied from an external power source of the chestpiece 110 (for example, the battery of the gripping part 120). The light-receiving element 204 may be, for example, a phototransistor or a complementary metal-oxide-semiconductor (CMOS) sensor.

[0027] The light-receiving element 204 is mounted on the 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 signals from the light-receiving element 204, signal terminals for outputting signals to external devices of the chestpiece 110, and power terminals for receiving power from an external power supply of the chestpiece 110. The light-receiving circuit board 205, including the light-receiving element 204, functions as a light-receiving unit.

[0028] 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.

[0029] The diaphragm 206 has a contact surface 206a that contacts a biological surface, which is an example of a target to be detected, and an inner surface 206b that is the opposite side of the contact surface 206a. The diaphragm 206 is configured to elastically deform when pressed by the target to be detected that comes into contact with the contact surface 206a. The contact surface 206a is the surface facing outward from the chestpiece 110, and the inner surface 206b is the surface facing inward from the chestpiece 110. The inner surface 206b of the diaphragm 206 is provided with a light-reflecting portion 207, which will be described later.

[0030] In this embodiment, the diaphragm 206 uses a laminate of glass epoxy resin, which is made by impregnating glass fibers with epoxy resin and then heat-curing it. Its thickness is 230 μm. The diaphragm 206 also has a ring-shaped rim integrated into it for fixing the diaphragm 206 to the retaining member 201 or the housing 208. In this embodiment, the contact surface 206a and inner surface 206b of the diaphragm 206 refer to the portion of the diaphragm that does not include the ring-shaped rim integrated into 206.

[0031] The diaphragm 206 is held by the retaining member 201. The diaphragm 206 extends along the xy plane of the coordinate system CS. The diaphragm 206 is positioned to contact a biological surface, which is an example of a target for detection. The diaphragm 206 constitutes part of the exterior of the chestpiece 110. The diaphragm 206 is positioned such that its contact surface 206a contacts a biological surface when the electronic stethoscope 100 is in use, and its inner surface 206b faces the retaining member 201.

[0032] The diaphragm 206 has a fixed portion 206c that is fixed to the holding member 201. The fixed portion 206c is located on the outer circumference of the diaphragm 206. The inner circumference 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 used, the diaphragm 206 vibrates with the fixed portion 206c as a node in response to the displacement of the biological surface. 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 detected.

[0033] The light-reflecting portion 207 reflects light emitted from the light-emitting element 202. The light-reflecting portion 207 is bonded to the inner surface 206b of the diaphragm 206 and moves integrally with the diaphragm 206 in the z-axis direction in conjunction with the vibration of the diaphragm 206, which is in close contact with the biological surface. The light-reflecting portion 207 has a circular outer edge in the plan view. The light-reflecting portion 207 may have a diameter of 15 mm to 20 mm. The light-reflecting portion 207 is positioned to cover the region 206d that includes the center 206e of the circle of the diaphragm 206. Since the displacement of the diaphragm 206 changes most significantly at the center 206e, the light from the light-emitting element 202 is reflected in the region including the center 206e. By reflecting light, the displacement of the diaphragm 206 can be detected with high sensitivity. In this embodiment, the light reflecting part 207 is positioned to cover the center 206e, but it may also be positioned to cover a region of the diaphragm 206 that does not include the center 206e.

[0034] The light-reflecting portion 207 is made of, for example, an aluminum vapor-deposited film. The light-reflecting portion 207 is a sheet-like member attached to the inner surface 206b (the surface opposite to the contact surface 206a) of the diaphragm 206. That is, the inner surface 206b functions as a reflective surface that reflects light emitted from the light-emitting element 202 toward the inner surface 206b. More specifically, the upper surface of the light-reflecting portion 207 reflects light emitted from the light-emitting element 202. That is, the upper surface of the light-reflecting portion 207 attached to the inner surface 206b functions as a reflective surface. In the following description, the reflection of light at the upper surface (i.e., the reflective 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, mirrorly reflects) the light emitted from the light-emitting element 202. In the following explanation, the light traveling from the light-emitting element 202 to the light-reflecting part 207 will be referred to as incident light 211, and the light after the incident light 211 has been reflected will be referred to as reflected light 212.

[0035] The light-emitting element 202 is positioned to emit light toward a region 207a of the light-reflecting portion 207 that includes the portion covering the center 206e of the diaphragm 206, when the diaphragm 206 is not in contact with the biological surface. When the diaphragm 206 is not in contact with the biological surface, the diaphragm 206 is flat. In this embodiment, as described above, an LED that emits diffuse light is used as the light-emitting element 202. Therefore, the chestpiece 110 has a diaphragm portion 209 that narrows the light emitted from the light-emitting element 202. The diaphragm portion 209 ensures that only a portion of the light emitted from the light-emitting element 202 enters the light-reflecting portion 207. In the example in Figure 2, the portion of the holding member 201 in which the opening is formed corresponds to the diaphragm portion 209.

[0036] In this embodiment, a component that emits diffused light was 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 region 207a. If the light-emitting element 202 is a component that emits linear light, the aperture portion 209 may be omitted. Also, in this embodiment, the portion of the holding member 201 in which an opening is formed was described as an example of the aperture portion 209. However, it may be a one-sided aperture instead of an opening. In that case, for example, a light-shielding wall for narrowing one side (upper or lower) of the light emitted from the light-emitting element 202 would be provided instead of an opening.

[0037] The light-receiving element 204 is positioned to receive reflected light 212. Specifically, the light-receiving element 204 is positioned so that the amount of reflected light 212 received changes due to the vibration of the diaphragm 206 in the z-axis direction. The light-receiving element 204 is positioned so that when the diaphragm 206 is not in contact with the biological surface (i.e., when the diaphragm 206 is flat), it receives more light in the reflected light 212 compared to when the diaphragm 206 is vibrating. In other words, the light-receiving element 204 outputs an electrical signal corresponding to the amount of reflected light 212 it receives, and the amount of displacement of the diaphragm 206 can be determined based on this electrical signal. This principle will be described later.

[0038] The chestpiece 110 has an aperture section 210 that narrows the light specularly reflected by the light reflecting section 207. The aperture section 210 suppresses diffusely reflected light from entering the light receiving element 204, allowing at least a portion of the light from the light reflecting section 207 (i.e., primary reflected light) to reach the light receiving element 204. In the example in Figure 2, the portion of the holding member 201 in which an opening is formed functions as the aperture section 210. In this embodiment, the portion of the holding member 201 in which an opening is formed was described as an example of the aperture section 210, but it may be a single-sided aperture instead of an opening. In that case, for example, a light-shielding wall to narrow one side (upper or lower side) of the light from the light reflecting section 207 would be provided instead of an opening.

[0039] A housing 208 is attached to the outer periphery of the retaining member 201. The housing 208 covers the light-emitting circuit board 203 and the light-receiving circuit board 205, and also suppresses ambient noise from entering the housing 208. The outer edge of the diaphragm 206, the outer edge of the retaining member 201, and the outer edge of the housing 208 substantially coincide with each other in a plan view with respect to the contact surface 206a of the diaphragm 206 when the diaphragm 206 is not in contact with the biological surface. In this embodiment, the housing 208 is made of metal, and the ground of the circuit boards in the chestpiece 110 (e.g., the light-emitting circuit board 203 and the light-receiving circuit board 205) is electrically connected to the housing 208. This stabilizes the ground potential.

[0040] The diaphragm 206 is fixed to the retaining member 201, forming an internal space 213 surrounded by the diaphragm 206 and the retaining member 201. The internal space 213 is sealed to prevent the light-receiving element 204 from receiving light other than that emitted by the light-emitting element 202. Furthermore, the diaphragm 206 and the retaining member 201 have light-shielding properties to prevent the light-receiving element 204 from receiving light other than that emitted by the light-emitting element 202. In the example in Figure 2, the fixing portion 206c of the diaphragm 206 is fixed to the retaining member 201. Alternatively, in the example in Figure 2, the fixing portion 206c of the diaphragm 206 may be fixed to the housing 208.

[0041] [Example of operation of the electronic stethoscope in the first embodiment] The operation of the chestpiece 110 of the electronic stethoscope 100 will be explained with reference to Figures 3A to 3D. Figures 3A and 3B show the state in which the diaphragm 206 is not pressed (i.e., is flat), and Figures 3C and 3D show the state in which the diaphragm 206 is pressed by the biological surface 320. In Figures 3A and 3C, the lower part shows a cross-sectional view of the chestpiece 110, and the upper part shows a plan view of the chestpiece 110. In the cross-sectional view of the chestpiece 110, the light-emitting circuit board 203, the light-receiving circuit board 205, and the housing 208 are omitted, and the shape of the holding member 201 is shown in detail. In the plan view of the chestpiece 110, only the light-emitting element 202, the light-receiving element 204, the light-reflecting part 207, the light-shielding wall 304, and the light-shielding wall 305 are shown. Figures 3B and 3D are perspective views focusing on the light-emitting element 202, the light-receiving element 204, the light-reflecting part 207, the light-shielding wall 304, and the light-shielding wall 305.

[0042] As shown in Figures 3A and 3C, the chestpiece 110 is used in contact with the biological surface 320 to be detected. That is, during use, the contact surface 206a of the diaphragm 206 of the chestpiece 110 is in close contact with the biological surface 320, which is an example of the detection target. As a result, the biological surface 320, the diaphragm 206, and the light reflecting part 207 vibrate together. Therefore, the chestpiece 110 detects the displacement of the inner surface 206b, i.e., the displacement of the upper surface of the light reflecting part 207 in the z-axis direction, as the displacement of the biological surface 320 in the z-axis direction. The displacement of the biological surface 320 occurs in response to bodily movements such as heartbeat and breathing of the person having the biological surface 320.

[0043] As shown in Figures 3A and 3B, the light-emitting element 202 and the light-receiving element 204 are arranged such that, when the diaphragm 206 is flat, more reflected light 212 is received by the light-receiving element 204 compared to when the diaphragm 206 is vibrating. The light-receiving element 204 amplifies and outputs a photocurrent corresponding to the amount of light it receives. The peripheral circuit of the light-receiving circuit board 205 generates an output value obtained by converting the photocurrent output from the light-receiving element 204 into a voltage, generates an output value as a displacement signal, converts this displacement signal into a digital signal, and outputs it to an external device. In this embodiment, the displacement signal refers to the output value of the light-receiving element 204 that reflects the state and deformation of the diaphragm 206 at any given time.

[0044] As shown in Figures 3C and 3D, the diaphragm 206 is pressed by the biological surface 320. When compressed, the biological surface 320 is displaced upward, which reduces the distance in the z-axis direction between the light-emitting element 202 and the upper surface of the light-reflecting part 207. Consequently, the region of the light-reflecting part 207 that the incident light 211 reaches moves closer to the light-emitting element 202, and the reflected light 212 also moves closer to the light-emitting element 202. As a result, the amount of reflected light 212 that reaches the photodetector 204 decreases, and the value of the displacement signal generated by the photodetector circuit board 205 becomes smaller.

[0045] In the chestpiece 110 shown in Figures 3A to 3D, the light-shielding wall 304 with an opening 306 functions as an aperture 209 on the incident light 211 side, and the light-shielding wall 305 with an opening 307 functions as an aperture 210 on the reflected light 212 side. In particular, the upper part of the upper edge of the opening 306 of the light-shielding wall 304 corresponds to the first aperture. Therefore, a portion of the light emitted by the light-emitting element 202 is blocked by the light-shielding wall 304 and does not reach the light-reflecting portion 207. Also, at least a portion of the light specularly reflected by the light-reflecting portion 207 is blocked by the light-shielding wall 305, depending on the position of the light-reflecting portion 207. In this embodiment, both the opening 306 and the opening 307 are rectangular. In the following explanation, of the four sides of each of the openings 306 and 307, the side parallel to the diaphragm 206 and closer to the diaphragm 206 will be referred to as the bottom side, the side parallel to the diaphragm 206 and further away from the diaphragm 206 will be referred to as the top side, the side to the left when viewed from the light-emitting element 202 will be referred to as the left side, and the side to the right when viewed from the light-emitting element 202 will be referred to as the right side.

[0046] In Figures 3A to 3D, the incident light 211 and reflected light 212 represent the light beams reaching the photodetector 204. In Figure 3B, some of the light 310 emitted from the light-emitting element 202 passes through the opening 306 of the light-shielding wall 304 and is reflected by the light-reflecting part 207 to become light 311, but is blocked by the part of the light-shielding wall 305 above the reflected light 212 and does not reach the photodetector 204. The same is true in Figure 3D.

[0047] As shown in Figures 3A and 3B, the portion of the light-reflecting part 207 that the incident light 211 reaches when the diaphragm 206 is not pressed by the biological surface 320 is referred to as the effective range 300. The effective range 300 is the portion of the light-reflecting part 207 that reflects light that reaches the photodetector 204. When the diaphragm 206 is not pressed by the biological surface 320, the effective range 300 is equal to the range to which light from the light-emitting element 202 reaches. In this embodiment, the effective range 300 is a rectangular area. The outer periphery of the effective range 300 is referred to as the boundary line of the effective range 300. The boundary line of the effective range 300 is located between the effective range 300 and the area outside the effective range 300. In the following description, a part of the boundary line is also referred to as the boundary line.

[0048] Of the four line segments that constitute the boundary of the effective range 300, the line segment containing the position furthest from the light-emitting element 202 in the x-axis direction is denoted as the far boundary line 300a. The portion of the incident light 211 that reaches the far boundary line 300a is denoted 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 section 207 that is the longest. The angle of incidence of the incident light 211 to the light-reflecting section 207 is at its maximum value of 303a at a position on the far boundary line 300a.

[0049] Of the four line segments that constitute the boundary of the effective range 300, the line segment containing the position closest to the light-emitting element 202 in the x-axis direction is denoted as the near boundary 300b. The portion of the incident light 211 that reaches the near boundary 300b is denoted as the near incident light 211b. The near incident light 211b means that it includes the portion where the optical path from the light-emitting element 202 to the light-reflecting section 207 is the shortest. The angle of incidence of the incident light 211 to the light-reflecting section 207 is at its minimum value of 303b at a position on the near boundary 300b. Of the light emitted from the light-emitting element 202, the 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 304.

[0050] Of the four line segments that constitute the boundary of the effective range 300, the far boundary line 300a and the near boundary line The two line segments other than the boundary line 300b are denoted as lateral boundary lines 300c and 300d. Lateral boundary line 300c is located to the right of the effective range 300 as viewed from the light-emitting element 202, and lateral boundary line 300d is located to the left of the effective range 300 as viewed from the light-emitting element 202.

[0051] As shown in Figures 3A and 3B, 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-illuminated region 301. The light-illuminated region 301 is the portion of the light-receiving element 204 that reaches the light emitted from the light-emitting element 202 and specularly reflected by the light-reflecting portion 207. In addition to the light specularly reflected by the light-reflecting portion 207, scattered light may also reach the light-receiving element 204, but in this embodiment, the region formed by specularly reflected light is defined as the light-illuminated region. The amount of light reaching the light-receiving element 204 is proportional to the area of ​​the light-illuminated region 301. In this embodiment, the light-illuminated region 301 is a rectangular region. The outer periphery of the light-illuminated region 301 is referred to as the boundary line of the light-illuminated region 301. The boundary line of the light-illuminated region 301 is located between the light-illuminated region 301 and the region other than the light-illuminated region 301.

[0052] Of the four line segments that constitute the boundary of the light-illuminated area 301, the line segment formed by light that is narrowed by the aperture 209 and specularly reflected by the light-reflecting part 207 is referred to as the lower boundary line 301a. Of the four line segments that constitute the boundary of the light-illuminated area 301, the line segment on the opposite side of the lower boundary line 301a is referred to as the upper boundary line 301b. The lower boundary line 301a is an example of a boundary line formed by light that is narrowed by the aperture 209 and specularly reflected by the light-reflecting part 207. The lower boundary line 301a is a boundary line that moves in accordance with the displacement of the contact surface 206a, as will be described later. In this embodiment, the area of ​​the light-illuminated area 301 changes as the lower boundary line 301a moves, and the output of the light-receiving element 204 changes. This makes it possible to accurately measure the displacement of the object to be detected. The upper boundary line 301b is an example of a boundary line that does not move in accordance with the displacement of the contact surface 206a and whose length does not change even if the contact surface 206a is displaced.

[0053] Of the four line segments that constitute the boundary of the light-irradiated area 301, the two line segments other than the lower boundary 301a and the upper boundary 301b are referred to as the lateral boundary 301c and lateral boundary 301d. The lateral boundary 301c is located to the right of the light-irradiated area 301 as viewed from the light-emitting element 202, and the lateral boundary 301d is located to the left of the light-irradiated area 301 as viewed from the light-emitting element 202. The lateral boundary 301c and lateral boundary 301d are examples of boundary lines that do not move in accordance with the displacement of the contact surface 206a, as will be described later, and whose length changes when the contact surface 206a is displaced.

[0054] Light passing through the aperture 306 along its upper edge is specularly reflected by the light reflecting section 207 and then reaches the lower boundary line 301a of the light-illuminating area 301 of the light-receiving element 204 without being obstructed by the light-shielding wall 305. Therefore, the upper edge of the aperture 306 defines the lower boundary line 301a of the light-illuminating area 301. On the other hand, light passing through the aperture 306 along its lower edge is specularly reflected by the light reflecting section 207 and then obstructed by the light-shielding wall 305, and does not reach the light-receiving element 204. Therefore, the lower edge of the aperture 306 does not define the light-illuminating area 301. Consequently, the near incident light 211b is not stopped by the aperture section 209. Alternatively, the light passing through the aperture 306 along its lower edge may be specularly reflected by the light reflecting section 207 and then reach the light-receiving element 204 without being obstructed by the light-shielding wall 305. In this case, the lower edge of the aperture 306 defines the light irradiation area 301. In this configuration, the displacement signal remains constant from zero to a predetermined value as the displacement of the diaphragm 206 decreases. Subsequently, when the lower edge of the aperture 306 no longer defines the light irradiation area 301, the displacement signal begins to decrease monotonically.

[0055] Light passing through the aperture 306 and specularly reflecting off the light reflecting section 207, and then passing along the upper edge of the aperture 307, reaches the upper boundary line 301b of the light-illuminating area 301 of the light-receiving element 204. Therefore, the upper edge of the aperture 307 defines the upper boundary line 301b of the light-illuminating area 301. In other words, the upper edge of the aperture 307 is an example of an aperture that narrows the light specularly reflected off the light reflecting section 207. On the other hand, because it is blocked by the light-shielding wall 304, light does not pass through the portion along the lower edge of the aperture 307. Therefore, the lower edge of the aperture 307 does not define the light irradiation area 301.

[0056] As shown in Figures 3A and 3C, the lateral boundary lines 301c and 301d of the light-irradiated area 301 are defined by the right and left sides of the aperture 307. Alternatively, the lateral boundary lines 301c and 301d of the light-irradiated area 301 may be defined by the right and left sides of the aperture 306.

[0057] The reflected light of the far incident light 211a is referred to as the lower end reflected light 212a. The lower end reflected light 212a is the light that is located furthest down in the z-axis direction of the reflected light 212 (i.e., the part closest to the diaphragm 206). The lower end reflected light 212a reaches the lower boundary line 301a of the light irradiation region 301. The lower boundary line 301a is formed by light that has been narrowed by the aperture 209 and specularly reflected by the light reflecting part 207. The lower end reflected light 212a is away from each side of the aperture 307. That is, the lower end reflected light 212a is not narrowed by the aperture 210. In the configurations of Figures 3A and 3B, the lower boundary line 301a includes the position in the light irradiation region 301 that is closest to the diaphragm 206 in the direction normal to the diaphragm 206 (i.e., in the z-axis direction) when the diaphragm 206 is not being pressed by the biological surface 320. Furthermore, in the configurations of Figures 3A and 3B, the lower boundary line 301a includes the position in the light irradiation area 301 where the light with the maximum reflection angle at the light reflecting portion 207 reaches. This maximum reflection angle is equal to the maximum incident angle 303a. Moreover, in the configurations of Figures 3A and 3B, the lower boundary line 301a includes the position furthest from the light-emitting element 202 in a plan view relative to the diaphragm 206 when it is not being pressed.

[0058] The reflected light from the near incident light 211b is denoted as the upper end reflected light 212b. The upper end reflected light 212b is the light that is located furthest upward in the z-axis direction of the reflected light 212 (i.e., the portion furthest from the diaphragm 206). The upper end reflected light 212b reaches the upper boundary line 301b of the light irradiation region 301. In the configurations of Figures 3A and 3B, the upper boundary line 301b includes the position in the light irradiation region 301 that is furthest from the diaphragm 206 in the direction normal to the diaphragm 206 (i.e., in the z-axis direction) when the diaphragm 206 is not pressed. Also, in the configurations of Figures 3A and 3B, the upper boundary line 301b includes the position in the light irradiation region 301 that reaches the light with the minimum reflection angle at the light reflecting part 207. This minimum reflection angle is equal to the minimum incident angle 303b. Furthermore, in the configurations of Figures 3A and 3B, the upper boundary line 301b includes the position closest to the light-emitting element 202 in a plan view relative to the diaphragm 206 when it is not being pressed.

[0059] As shown in Figures 3C and 3D, when the diaphragm 206 is pressed against the biological surface 320, the positions of the effective range 300, the far boundary line 300a, the near boundary line 300b, the light irradiation area 301, the lower boundary line 301a, and the upper boundary line 301b change, respectively. Of the reflected light 212, the portion furthest from the light-emitting element 202 in the x-axis direction is called the lower end reflected light 212a. The lower end reflected light 212a reaches the lower boundary line 301a of the light irradiation area 301. As described above, the lower boundary line 301a is defined by the upper edge of the opening 306 of the aperture portion 209 on the light-emitting element 202 side. The lower boundary line 301a moves in accordance with the displacement of the contact surface 206a due to the elastic deformation of the diaphragm 206, and as a result, the area of ​​the light irradiation area 301 changes, and the output of the photodetector 204 also changes, as will be described later.

[0060] The lower boundary line 301a is displaced by a displacement ratio G with respect to the displacement of the diaphragm 206. Similarly, the position where the part of the reflected light 212 that is furthest from the light-emitting element 202 (in three-dimensional space, regardless of the x-axis direction) reaches the photodetector 204 is also displaced by a displacement ratio G. The displacement ratio G has a value corresponding to the angle of incidence of the incident light 211 to the light-reflecting part 207 and the angle of the light-receiving surface of the photodetector 204 relative to the light-reflecting part 207. The chestpiece 110 may be configured such that the displacement ratio G is greater than 1.5, or so that the displacement ratio G is greater than 2. It's okay.

[0061] As shown in Figures 3A to 3D, the upper boundary line 301b is defined by the portion of the light-shielding wall 305 above the reflected light 212, and is a boundary line that does not move in accordance with the displacement of the contact surface 206a and whose length does not change even if the contact surface 206a is displaced. The portion of the light-shielding wall 304 below the incident light 211 does not need to shield the light emitted from the light-emitting element 202. For example, the portion of the light-shielding wall 304 below the incident light 211 does not need to be provided. Also, the lower boundary line 301a is defined by the portion of the light-shielding wall 304 above the incident light 211. Therefore, the portion of the light-shielding wall 305 below the reflected light 212 does not need to shield the light specularly reflected by the light-reflecting portion 207. For example, the portion of the light-shielding wall 305 below the reflected light 212 does not need to be provided.

[0062] [Changes in the range of reflected light in the electronic stethoscope in the first embodiment] Referring to Figure 3E, the changes in the light-irradiated area 301 formed by the reflected light 212 that reaches the light-receiving surface of the photodetector 204 will be explained. Figure 3E shows a plan view of the photodetector 204 with respect to the light-receiving surface. The left side of Figure 3E shows the position of the light-irradiated area 301 when the diaphragm 206 is not pressed. The right side of Figure 3E shows the position of the light-irradiated area 301 when the diaphragm 206 is pressed by the biological surface 320.

[0063] To illustrate direction, the coordinate system CS' is shown in Figure 3E. The coordinate system CS' is a two-dimensional Cartesian coordinate system with mutually orthogonal x' and y' axes. 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 explanation, the positive x' axis direction is referred to as "up," and the negative x' axis direction is referred to as "down."

[0064] The surface of the light-receiving element 204 that faces the internal space 213 becomes 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 represented as side 204a.

[0065] The area of ​​the light-irradiated region 301 is defined by the lower boundary line 301a, the upper boundary line 301b, and the lateral boundary lines 301c and 301d. As shown in Figure 3E, the lower boundary line 301a of the light-irradiated region 301 changes in the x' axis direction in response to the displacement of the contact surface 206a. On the other hand, the upper boundary line 301b, the lateral boundary lines 301c and 301d do not move substantially in response to the displacement of the contact surface 206a. Therefore, the area of ​​the light-irradiated region 301 changes in response to the movement of the lower boundary line 301a. The length of the upper boundary line 301b does not change even if the contact surface 206a is displaced. On the other hand, the lengths of the lateral boundary lines 301c and 301d change when the contact surface 206a is displaced.

[0066] When the area of ​​the light-illuminated region 301 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 a flat state, the shorter the distance between the lower boundary line 301a and the upper boundary line 301b (i.e., the lengths of the lateral boundary lines 301c and 301d), and the smaller the area of ​​the light-illuminated region 301. Therefore, the greater the displacement of the diaphragm 206 from a flat state, the less light the light-receiving element 204 receives. Accordingly, the signal output from the light-receiving element 204 also becomes smaller. The amount of movement of the lower boundary line 301a accompanying the movement of the light-reflecting portion 207 is greater than the amount of movement of the upper boundary line 301b accompanying the movement of the light-reflecting portion 207.

[0067] As shown in Figure 3E, the change in the x' axis direction of the light-irradiated region 301 is greater than the change in the y' axis direction of the light-irradiated region 301. Therefore, the dynamics of the photodetector 204 To increase the clean range, it is preferable that the width of the photodetector 204 in the x' axis direction be greater than the width of the photodetector 204 in the y' axis direction. More specifically, it is preferable that the width of the photodetector 204 in the x' axis direction be three times or more the width of the photodetector 204 in the y' axis direction.

[0068] [Relationship between displacement amount on the biological surface of the electronic stethoscope and displacement signal in the first embodiment] Referring to Figure 4, the relationship between the displacement of the biological surface 320 and the displacement signal will be explained. The displacement signal is the voltage output from the light-receiving circuit board 205. Graph 400 in Figure 4 shows the relationship between the displacement of the biological surface 320 [mm] and the displacement signal [V]. The horizontal axis of graph 400 represents the displacement of the biological surface 320, and the vertical axis of graph 400 represents the displacement signal generated by the light-receiving circuit board 205.

[0069] As described above, the displacement of the biological surface 320 is equal to the displacement of the upper surface of the light reflecting part 207. The displacement of the upper surface of the light reflecting part 207 is equal to the displacement of the diaphragm 206 (inner surface 206b). As shown in Figure 4, as the displacement of the reflected light 212 increases, the amount of reflected light 212 that reaches the photodetector 204 decreases monotonically and linearly. Therefore, if the displacement of the biological surface 320 is d and the value of the displacement signal is S, S=Vmax-k×d…(Formula 1) This is the result. Here, Vmax is the value of the displacement signal when the displacement d is zero. Vmax is determined by the amount of light emitted by the light-emitting element 202 and the sensitivity of the photodetector 204. The sensitivity of the photodetector 204 refers to the change in output voltage per unit amount of light incident on the photodetector 204. Vmax is larger the higher the sensitivity of the photodetector 204. Also, Vmax is larger the higher the amount of light emitted by the light-emitting element 202. k is the amplification factor of the photodetector 204. k is also determined by the amount of light emitted by the light-emitting element 202 and the sensitivity of the photodetector 204. k is larger the higher the sensitivity of the photodetector 204. Also, k is larger the higher the amount of light emitted by the light-emitting element 202.

[0070] The displacement amount d at which the displacement signal S becomes zero is denoted as dmax. For example, dmax is 1 mm. As the displacement amount d of the biological surface 320 increases, the area of ​​the light-irradiated region 301 decreases and becomes zero. When the area of ​​the light-irradiated region 301 becomes zero, the displacement signal S also becomes zero. The displacement amount d at which the area of ​​the light-irradiated region 301 becomes zero is determined by the respective positions of the light-receiving element 204 and the aperture portion 210 relative to the reflected light 212.

[0071] When the displacement d exceeds dmax, the reflected light 212 no longer reaches the photodetector 204, so even if the displacement d increases, the displacement signal S remains zero. Therefore, the chestpiece 110 is configured such that the displacement d is in the range of 0 or more and dmax or less within the range in which the vibration of the diaphragm 206 is expected (this is referred to as the operating range of the diaphragm 206). As shown in Graph 400, the light-emitting element 202 and the photodetector 204 are arranged such that the amount of light reaching the photodetector 204 (amount of light received) changes monotonically in response to the movement of the light-reflecting part 207 in one direction within the operating range of the diaphragm 206. In the example in Figure 4, the photodetector 204 is arranged so that the amount of light received decreases monotonically, but the photodetector 204 may also be arranged so that the amount of light received monotonically increases.

[0072] In this embodiment, the light-emitting element 202 and the light-receiving element 204 are arranged such that all of the reflected light 212 reaches the light-receiving element 204 when the diaphragm 206 is flat. Alternatively, the light-emitting element 202 and the light-receiving element 204 may be arranged such that all of the reflected light 212 reaches the light-receiving element 204 when the diaphragm 206 is displaced below flat.

[0073] In the embodiment described above, the normal to the light-receiving surface of the light-receiving element 204 is the z-axis direction (i.e., the da It is inclined with respect to the normal direction of the ear diaphragm 206. Alternatively, the normal of the light-receiving surface of the light-receiving element 204 may coincide with the z-axis direction. In this case, the light-receiving surface will be parallel to the diaphragm 206.

[0074] With the above configuration, the chestpiece 110 according to the first embodiment functions as a detection device capable of accurately detecting the displacement and vibration of the biological surface 320. Specifically, in the chestpiece 110 described above, when the biological surface, which is an example of the detection target, is in close contact with the diaphragm 206, a displacement signal is generated based on the amount of displacement of the biological surface 320, which vibrates together with the diaphragm 206. Therefore, the displacement of the biological surface 320 can be accurately detected regardless of the frequency at which the biological surface 320 vibrates. For example, even displacement of the biological surface 320 due to low-frequency vibrations of about 10 Hz can be accurately detected. Such low-frequency vibrations are included in sounds (e.g., heart sounds) emitted by vibrations propagated from inside the body by the heartbeat. In the chestpiece 110, the displacement signal does not change unless the diaphragm 206 is displaced. Therefore, ambient sound and vibrations or accelerations due to the movement of the chestpiece 110 are not detected as noise, and a high S / N ratio output characteristic can be obtained.

[0075] [Hardware configuration of the electronic stethoscope in the first embodiment] Referring to Figure 5, an example of the hardware configuration of the electronic stethoscope 100 will be described. Figure 5 is a diagram showing an example of the hardware configuration of the electronic stethoscope 100 according to the first embodiment. The electronic stethoscope 100 includes a chestpiece 110 as a detection device for detecting the displacement and vibration of the biological surface 320 described above, a sound output unit 510, a calibration execution unit 520, and a determination unit 530.

[0076] The sound output unit 510 is realized by multiple circuit elements mounted on a circuit board included in the gripping unit 120. These multiple circuit elements include a processor. The processor constituting the sound output unit 510 transmits a sound signal based on the displacement signal generated by the chestpiece 110 to an external sound output device. The sound signal transmitted by the sound output unit 510 represents the biological sound of a living organism (e.g., a human) with a biological surface 320, and is therefore also called a biosound signal. Both the displacement signal and the sound signal (biosound signal) are waveform signals. The sound signal is transmitted to a sound output device 540, such as earphones or headphones. Simultaneously with the transmission to the sound output device 540, the sound signal is also transmitted to a computer 550 (e.g., a personal computer, smartphone, tablet, etc.). Users such as doctors, nurses, and public health nurses can listen to the biological sound represented by the digitally converted sound signal using the sound output device 540 or the computer 550. The sound output device 540 is, for example, a wired or wireless earphone or headphones.

[0077] The sound output unit 510 is a sound signal generation unit that generates sound signals (biometric signals) based on the displacement signals generated by the chestpiece 110. The sound output unit 510 is compliant with the earphones or headphones described above and can transmit sound signals via both wireless and wired communication. The sound output unit 510 can be configured with filters and amplifiers for filtering and amplifying the displacement signals output from the chestpiece 110, and an A / D converter for digitizing the output.

[0078] Furthermore, the sound output unit 510 may include a wired communication unit such as an AUX terminal, or a wireless communication unit compliant with a wireless communication standard such as Bluetooth®. For example, the sound signal generated by filtering and amplifying the displacement signal may be provided to the sound output device 540 or computer 550 via the wired communication unit. Alternatively, the sound signal generated by filtering, amplifying, and digitizing the displacement signal may be provided to the sound output device 540 or computer 550 via the wireless communication unit. The electronic stethoscope 100 is capable of outputting sound signals via both wireless and wired communication. It is also possible to output an audio signal by only one of these communications. Furthermore, the audio output device 540 may be considered as part of the electronic stethoscope 100. In addition, some or all of the components of the audio output unit 510 may be provided within the chestpiece 110.

[0079] The computer 550 can also visually display waveform data generated based on the sound signal. The waveform data may be generated by the computer 550 or by the electronic stethoscope 100. In addition, some or all of the signal processing and sound output processing by the electronic stethoscope 100 may be performed by an external device (e.g., a sound output device 540 or the computer 550).

[0080] The calibration execution unit 520 is a calibration execution means that accurately detects the displacement and vibration of the biological surface 320 and performs calibration to obtain biological signals and sound signals with high accuracy. Details of the calibration will be described later. The determination unit 530 is a determination means that performs various determination operations on the displacement signal generated by the chestpiece 110 and the sound signal generated by the sound output unit 510. The calibration execution unit 520 and the determination unit 530 are each configured to include a processor. The processors that make up the sound output unit 510, the calibration execution unit 520, and the determination unit 530 may be common to each other, or they may each be provided independently.

[0081] The electronic auscultation device 100 can accurately detect the displacement of the biological surface 320 regardless of the frequency at which the biological surface 320 vibrates. Therefore, the electronic auscultation device 100 enables good auscultation of both relatively low-frequency biological sounds such as heart sounds emitted by the body due to heartbeat, and relatively high-frequency biological sounds emitted by the body due to respiration. Respiratory sounds are biological vibrations that include a frequency band (first frequency band) containing components in the frequency range of 500 Hz to 1 kHz, for example. Heart sounds are biological vibrations that include a frequency band (second frequency band) containing components in the frequency range of 30 Hz to 300 Hz, for example.

[0082] The operating unit 123 of the electronic stethoscope 100 is provided with a mode switching button 123c. When the mode switching button 123c is pressed, the auscultation mode of the electronic stethoscope 100 switches between a mode suitable for auscultation of heart sounds (hereinafter referred to as "heart sound mode") and a mode suitable for auscultation of breath sounds (hereinafter referred to as "breath sound mode"). The electronic stethoscope 100 may also have auscultation modes other than the heart sound mode and the breath sound mode. The auscultation mode can also be described as a detection mode that detects displacement or vibration of the biological surface 320. When auscultating heart sounds, the user operates the mode switching button 123c provided on the operating unit 123 to select the heart 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 operating unit 123 to select the breath sound mode, which is one of the auscultation modes.

[0083] Furthermore, the electronic stethoscope 100 automatically switches to a power-saving mode that consumes less power than the heart sound mode or respiratory sound mode under certain conditions, such as when not in use. In power-saving mode, for example, the power supplied to the light-emitting element 202 and the light-receiving element 204 is less than in auscultation mode. When any operation is performed on the electronic stethoscope 100, it switches (returns) from power-saving mode to auscultation mode. Alternatively, the electronic stethoscope 100 may be configured to automatically turn off if the power-saving mode continues for a certain period of time or longer.

[0084] The control unit 123 is equipped with a volume up button 123a and a volume down button 123b, which are volume adjustment buttons for adjusting the gain of the displacement signal output by the electronic stethoscope 100. The volume up button 123a and the volume down button 123b are used to adjust the volume of the sound output by the electronic stethoscope 100. Furthermore, the display unit 122 of the electronic stethoscope 100 is equipped with an LED as an indicator to show whether the current auscultation mode is heart sound mode or respiratory sound mode. The user can visually confirm whether the operating mode is heart sound mode or respiratory sound mode by the state of illumination of this LED. Note that heart sound mode and respiratory sound mode are examples of auscultation modes.

[0085] [Attachment / Detachment Mechanism of Electronic Stethoscope in First Embodiment] The chestpiece 110 of the electronic stethoscope 100 has a base unit 140 and a replacement unit 160 including a diaphragm 206. The diaphragm 206 may need to be replaced due to aging or wear of the contact surface. However, if only the diaphragm 206 is a replacement 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 that case, the measurement accuracy will be affected by the characteristics of the diaphragm and the precision and optical characteristics of the parts to which the optical sensor is attached. Therefore, the electronic stethoscope 100 is configured so that the replacement unit 160 including the diaphragm 206 can be easily attached to and detached from the base unit 140.

[0086] Figure 6A is a cross-sectional view of the electronic auscultation device 100 in a plane parallel to the xz plane. Figure 6B is a perspective view showing a part of the base unit 140. Figure 6C is a view focusing on a part of the base unit 140 in the cross-sectional view of Figure 6A. Figure 6D is a perspective view of the replacement unit 160. Figure 6E is a view focusing on the replacement unit 160 in the cross-sectional view of Figure 6A.

[0087] As shown in Figure 6A, the electronic stethoscope 100 includes a base unit 140 and a replacement unit 160. The base unit 140 is a part of the electronic stethoscope 100 that is not expected to be replaced by user operation during its product life. The base unit 140 includes a gripping part 120 and a part of the chestpiece 110. However, not all components of the base unit 140 are expected to be replaced; some components of the base unit 140 can be replaced by factory repairs, etc. Also, the battery 127 of the gripping part 120 can be replaced by the user.

[0088] The replacement unit 160 is a part of the electronic stethoscope 100 that is expected to be replaced by user operation within the product lifespan. In the electronic stethoscope 100, the replacement unit 160 is coupled to the base unit 140 so that it can be attached and detached by user operation. The electronic stethoscope 100 has a detachment mechanism that connects the replacement unit 160 to the base unit 140 so that it can be attached and detached by user operation. Hereinafter, such a detachment mechanism will be referred to as the detachment mechanism of the electronic stethoscope 100, or simply as the detachment mechanism.

[0089] The gripping section 120 includes a main circuit board 126 and a battery 127. The main circuit board 126 includes circuit elements (e.g., integrated circuits, electrode pads, conductive patterns, etc.) for controlling the operation of the entire electronic stethoscope 100. Specifically, the main circuit board 126 controls the operation of the chestpiece 110, the display section 122, and the operation of the operating section 123. For example, the main circuit board 126 constitutes the sound output section 510 (Figure 5) described above. The main circuit board 126 may be plate-shaped and may have a mounting surface parallel to the xy plane. The longitudinal direction of the main circuit board 126 (e.g., the direction in which the long side of the mounting surface extends) may be considered to be the longitudinal direction of the gripping section 120. In this embodiment, the battery 127 has a plate-shaped or columnar shape, and the longitudinal direction of the battery 127 coincides with the longitudinal direction of the gripping section 120.

[0090] The chestpiece 110 includes a relay circuit board 161, a connector 162, a locking pin 163, a relay circuit board 141, a connector 142, and a connector 143.

[0091] The relay circuit board 161 is connected to the holding member 201. Also, the relay circuit board 141 These are coupled to the inner surface of the housing 208. These couplings can be made, for example, by fasteners such as screws.

[0092] The relay circuit board 161 is connected to the light-emitting circuit board 203 by lead wires (not shown). Through these lead wires, the relay circuit board 161 transmits control signals to the light-emitting circuit board 203 to instruct it to emit light and supplies power to it. The relay circuit board 161 is also connected to the light-receiving circuit board 205 by lead wires (not shown). Through these lead wires, the relay circuit board 161 receives displacement signals from the light-receiving circuit board 205 and supplies power to the light-receiving circuit board 205.

[0093] When the replacement unit 160 is mounted on the base unit 140, the upper surface of the relay circuit board 161 and the lower surface of the relay circuit board 141 face each other. A connector 162 is mounted on the upper surface of the relay circuit board 161, and connectors 142 and 143 are mounted on the lower surface of the relay circuit board 141. Connectors 142 and 143 are electrically connected to each other by a conductive pattern formed on the relay circuit board 141. Connector 142 includes multiple electrical contacts, and a portion of each electrical contact is exposed on the lower surface of connector 142. Connector 162 includes multiple electrical contacts, and a portion of each electrical contact is exposed on the upper surface of connector 162.

[0094] A bundle of wires 128 extending through a hole 208a in the housing 208 is connected to the connector 143 of the relay circuit board 141. The connector 142 of the relay circuit board 141 is connected to the connector 162 of the relay circuit board 161.

[0095] Connector 162 is provided with a plurality of connection pins 162a as a first connection part. Connector 142 is provided with a plurality of pin holes 142a into which the connection pins 162a are inserted as a second connection part. In this example, there are five connection pins 162a and five pin holes 142a. Connector 162 and connector 142 are electrically connected when the connection pins 162a and pin holes 142a are connected (mating). Note that the first connection part provided on connector 162 may consist of pin holes, and the second connection part provided on connector 142 may consist of connection pins. In other words, it is sufficient that one of the connectors, 162 or 142, has connection pins and the other has pin holes corresponding to the connection pins. Note that the connection pins 162a in the first embodiment are spring pins.

[0096] With the above configuration, signals from the relay circuit board 161 are transmitted to the main circuit board 126, which is installed on the gripping section 120, via connectors 162, 142, 143, and wire bundle 128. Power from the main circuit board 126 is supplied to the relay circuit board 161 via connectors 162, 142, 143, and wire bundle 128.

[0097] Of the components of the chestpiece 110, the retaining 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 part 207, the relay circuit board 161, and the connector 162 are included in the replacement unit 160. Of the components of the chestpiece 110, the housing 208, the relay circuit board 141, the connector 142, and the connector 143 are included in the base unit 140. Therefore, in the electronic stethoscope 100, not only the diaphragm 206 is replaced, but the components that constitute the displacement detection unit (light-emitting element 202, light-receiving element 204, and light-reflecting part 207) that detect the displacement and vibration of the biological surface 320 are replaced together with the diaphragm 206.

[0098] In this embodiment, the light reflecting portion 207 is attached to the diaphragm 206. Therefore, if the diaphragm 206 is removed from the holding member 201 by user operation and replaced with another diaphragm 206, the positional relationship between the light-emitting element 202 and the light reflecting portion 207, or This could cause a change in the positional relationship between the light-receiving element 204 and the light-reflecting part 207. If these positional relationships change, it may become impossible to accurately detect the displacement of the biological surface. Therefore, in this embodiment, by including the components constituting the displacement detection unit and the diaphragm 206 in the replacement unit 160, it becomes possible to replace the diaphragm 206 without reducing the accuracy of detecting the displacement of the biological surface.

[0099] 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 160 can be attached to and detached from the base unit 140 by 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 suppresses a decrease in the detection accuracy of displacement of the biological surface due to a shift in their positional relationship. Furthermore, the replacement unit 160 can be attached to and detached from the base unit 140 while maintaining the internal space 213 facing the inner surface 206b of the diaphragm 206. In other words, the light-reflecting part 207, the light-emitting element 202, and the light-receiving element 204 cannot be touched by the user during unit replacement. This suppresses a decrease in the detection accuracy of displacement of the biological surface due to contamination of the light-reflecting part 207, the light-emitting element 202, and the light-receiving element 204 caused by user operation.

[0100] In the first embodiment, the connector 129 of the main circuit board 126 included in the gripping section 120 and the connector 143 of the relay circuit board 141 coupled to the housing 208 are electrically connected by a bundle of wires 128. Furthermore, the connector 142 of the relay circuit board 141 included in the base unit 140 and the relay circuit board 161 included in the replacement unit 160 are electrically connected by a detachment mechanism that connects the base unit 140 and the replacement unit 160. This configuration allows for the attachment and detachment of the replacement unit 160, which includes the displacement detection section and the diaphragm 206. In other words, the electronic stethoscope 100 offers excellent ease of replacement of the replacement unit 160.

[0101] The shapes of the retaining member 201 and the housing 208 will be described in more detail with reference to Figures 6D and 6E. The retaining member 201 includes a side wall 164e that extends along the outer circumference of the diaphragm 206. In the electronic stethoscope 100 of this embodiment, the retaining member 164 provided in the replacement unit 160 has a side wall 164e.

[0102] As shown in Figures 6B and 6C, the housing 208 has a cylindrical portion 208b and a top plate portion 208c. The top plate portion 208c is a curved portion that is circumferentially connected to the upper end of the cylindrical portion 208b and is integrally molded with the cylindrical portion 208b. The central part of the top plate portion 208c protrudes upward. A connecting member for connecting the housing 208 to the gripping portion 120 may be provided on this protruding portion.

[0103] When the replacement unit 160 is coupled to the base unit 140, the cylindrical portion 208b is located outside the side wall 164e and surrounds the side wall 164e. The outer diameter of the side wall 164e and the inner diameter of the cylindrical portion 208b are approximately equal. The lower end of the cylindrical portion 208b of the housing 208 is in contact with the retaining member 201. When the housing 208 is coupled to the retaining member 201, the housing 208 covers the components held by the retaining 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 161 on which the connector 162 is mounted.

[0104] The attachment / detachment mechanism of the electronic stethoscope 100 consists of a locking pin 163 and a hole 208d formed in the housing 208. A hole is formed in the side wall 164e for the locking pin 163 to pass through. The side wall 164e supports the locking pin 163 so that the locking pin 163 can move in the longitudinal direction of the locking pin 163.

[0105] When the replacement unit 160 is connected to the base unit 140, the locking pin 163 passes through both the hole in the side wall 164e and the hole 208d in the housing 208, with its tip protruding from the housing 208. The locking pin 163 is biased outward from the chestpiece 110 by a biasing member such as a spring. Therefore, unless an external force is applied, the locking pin 163 maintains a state where its tip protrudes from the housing 208. The base of the locking pin 163 is thicker than the hole in the side wall 164e to prevent it from falling out of the chestpiece 110.

[0106] The locking pin 163 has a spherical portion that forms its tip and a cylindrical portion extending from the spherical portion. When no external force is applied to the locking pin 163, the cylindrical portion of the locking pin 163 is located inside the hole 208d in the side wall 164e. As a result, unless an external force is applied to the locking pin 163, the range of movement of the replacement unit 160 relative to the base unit 140 is limited to the gap between the locking pin 163 and the housing 208. In other words, the movement of the replacement unit 160 relative to the base unit 140 is locked by the locking pin 163.

[0107] On the other hand, when the lock pin 163 is pushed inward by user operation, the spherical portion of the lock pin 163 is positioned inside the hole 208d in the side wall 164e. In this state, when the replacement unit 160 is pulled upward in the z-axis direction relative to the base unit 140, the side wall 164e pushes the lock pin 163 further inward, allowing the replacement unit 160 to move and be removed from the base unit 140. In other words, the lock pin 163 is released from the lock on the movement of the replacement unit 160 relative to the base unit 140.

[0108] The electronic stethoscope 100 further includes a restricting mechanism that restricts the movement path of the replacement unit 160 relative to the base unit 140. In the electronic stethoscope 100, the restricting mechanism is composed of a protrusion 208e provided on the inner surface of the cylindrical portion 208b of the housing 208 and a slit 164f provided on the side wall 164e of the holding member 201. The protrusion 208e and the slit 164f restrict the movement path of the replacement unit 160 relative to the base unit 140 to movement in the direction normal to the contact surface 206a of the diaphragm 206. This ensures that the connectors 142 and 162 are connected at the correct angle. In the example shown in Figure 6B, the protrusion 208e is a rectangular parallelepiped, but it may be another shape, such as a cube, that can pass through the slit 164f. The slit 164f has an L-shape. Specifically, the slit 164f includes a vertical portion extending from the upper end of the side wall 164e in the direction normal 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 circumference of the diaphragm 206. In the example shown in Figure 6D, the slit 164f penetrates the side wall 164e, but it may also be configured to form a recess in the side wall 164e.

[0109] The user operation for attaching and detaching the replacement unit 160 to the base unit 140 will now be described. The user operation for removing the replacement unit 160 from the base unit 140 includes pressing the locking pin 163, rotating the replacement unit 160 relative to the base unit 140, and then moving the replacement unit 160 away from the base unit 140. As described above, pressing the locking pin 163 releases the lock on the movement of the replacement unit 160 relative to the base unit 140. In this state, the replacement unit 160 is removed from the base unit 140 by moving the replacement unit 160 relative to the base unit 140 so that the protrusion 208e moves along the slit 164f. This user operation causes the electrical contacts of connector 142 and connector 162 to separate from each other.

[0110] The user operation for attaching the replacement unit 160 to the base unit 140 includes aligning the protrusion 208e with the slit 164f, then moving the replacement unit 160 toward the base unit 140 while pressing the locking pin 163, and then rotating the replacement unit 160 relative to the base unit 140. When the replacement unit 160 is properly coupled to the base unit 140, the locking pin 163 protrudes from the hole 208d, locking the movement of the replacement unit 160 relative to the base unit 140. This user operation causes the electrical contacts of connector 142 and the electrical contacts of connector 162 to make contact with each other. Since the connector 162 included in the replacement unit 160 is located outside the internal space 213, the connector 162 is coupled to connector 142 while maintaining the internal space 213.

[0111] The restricting mechanism for controlling the movement path of the replacement unit 160 relative to the base unit 140 is not limited to the configuration described above. For example, the restricting mechanism may consist of 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 164e. In this case, the user operation for removing the replacement unit 160 from the base unit 140 may be to rotate the replacement unit 160 relative to the base unit 140 while pressing the lock pin 163.

[0112] The electronic stethoscope 100 includes two locking pins 163. The number of locking pins 163 does not have to be two; there may be one or more, but there may be two or fewer locking pins 163 to make it easier for the user to operate the locking pins 163 with their fingertips. In the electronic stethoscope 100, the locking pins 163 are included in the replacement unit 160, and the holes 208d that engage with the locking pins 163 are included in the base unit 140. Alternatively, the locking pins may be included in the base unit 140, and the holes that engage with the locking pins may be included in the replacement unit 160. The electronic stethoscope 100 does not have to include a gripping part 120, and may consist of a chestpiece 110 alone. In this case as well, the chestpiece 110 may be divided into a base unit and a replacement unit. The attachment / detachment mechanism using the locking pins 163 enables attachment and detachment without the need for tools such as a screwdriver. Alternatively, the operation of attaching or detaching the replacement unit 160 to the base unit 140 may include the use of tools, such as using a screwdriver to remove screws.

[0113] After the replacement unit 160 is removed from the base unit 140, the same replacement unit 160 may be attached to the base unit 140, or a different replacement unit 160 may be attached to the base unit 140. The positional relationship between the light reflecting part 207, the light-emitting element 202, and the light-receiving element 204 in the replacement unit 160 varies from replacement unit 160 to replacement unit 160 due to manufacturing tolerances, etc. Therefore, the parameters determined by this positional relationship have values ​​unique to each replacement unit 160. 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 160 may further include a memory 165 that stores the parameters determined by the positional relationship between the light reflecting part 207, the light-emitting element 202, and the light-receiving element 204. The memory 165 may be mounted, for example, on the relay circuit board 161. After the replacement unit 160 is mounted on the base unit 140, the sound output unit 510, which is implemented by the main circuit board 126 included in the base unit 140, may read parameters from the memory 165 and adjust the signal generation according to these parameters.

[0114] [Attachment / detachment detection configuration of the first embodiment] The electronic stethoscope 100 has an attachment / detachment detection configuration that can detect the attachment / detachment operation and status of the replacement unit 160 to the base unit 140. The attachment / detachment detection configuration of the electronic stethoscope 100 will be explained with reference to Figure 7. Figure 7 illustrates the attachment / detachment detection configuration of the electronic stethoscope 100. This is a schematic diagram. The attachment / detachment detection configuration consists of multiple circuits provided in the gripping part 120 and the chestpiece 110. The circuit provided in the base unit 140 and the circuit provided in the replacement unit 160 are electrically connected by connecting the connection pin 162a and the pin hole 142a.

[0115] The gripping section 120 is equipped with a control unit 601, a power supply unit 602, a light intensity adjustment unit 603, an amplifier 604, a filter 605, and a buffer circuit 606. In the first embodiment, these components are formed on the main circuit board 126. The part of the chestpiece 110 that constitutes the base unit 140 is equipped with a switch (hereinafter referred to as SW) circuit section 611 and five connection pins 162a. The part of the chestpiece 110 that constitutes the replacement unit 160 is equipped with a light-emitting circuit board 203, a light-receiving circuit board 205, and five pin holes 142a.

[0116] The control unit 601 includes a processor and non-volatile memory, and transmits and receives various signals to control the operation of the chestpiece 110 and detect the attachment and detachment of the replacement unit 160. In the first embodiment, the control unit 601 constitutes the calibration execution unit 520. Alternatively, the control unit 601 may constitute the determination unit 530 shown in Figure 5. In other words, the processor of the control unit 601 may be configured to perform various determinations.

[0117] The power supply unit 602 includes a power supply for supplying operating power to the electronic stethoscope 100. The power supply unit 602 can be composed of multiple power supplies with different voltage values. For example, the power supply unit 602 may be configured to include a first power supply for the control unit 601 with a voltage value of +3.3V and a second power supply for the light-emitting unit with a voltage value of +10V.

[0118] The SW circuit 611 is configured to switch the power supply state from the power supply unit 602 to the light-emitting circuit board 203 and the light-receiving circuit board 205. The switching of the SW circuit 611 is controlled by the control unit 601. When the replacement unit 160 is connected to the base unit 140, the SW circuit 611 is turned off (open), and power is not supplied, preventing damage to various circuits.

[0119] The light intensity adjustment unit 603 is connected to the light-emitting circuit board 203 and is configured to adjust the light intensity of the light-emitting element 202. The light intensity adjustment unit 603 adjusts the light intensity of the light-emitting element 202 based on signals received from the control unit 601 and transmits a signal to cause the light-emitting element 202 to emit light.

[0120] The amplifier 604, filter 605, and buffer circuit 606 are connected to the light-receiving circuit board 205 and filter and amplify the output of the light-receiving element 204. The amplifier 604, filter 605, and buffer circuit 606 are components of the sound output section 510. The buffer circuit 606 is a circuit for correcting voltage drop and receives the output signal (displacement signal in this example) from the light-receiving circuit board 205. The filter 605 filters the output signal received from the light-receiving circuit board 205 via the buffer circuit 606. The filter 605 includes, for example, a high-pass filter and a low-pass filter. The amplifier 604 amplifies the displacement signal filtered by the filter 605. The displacement signal filtered and amplified by the filter 605 and amplifier 604 is sent to the control unit 601 as a biosignal (sound signal). Furthermore, the buffer circuit 606 can transmit a contact detection signal indicating the presence or absence of contact with the diaphragm 206 to the control unit 601 based on the displacement signal, without going through the filter 605 or amplifier 604.

[0121] In the following explanation, as shown in Figure 7, the five connection pins 162a will be referred to as connection pins 162a1, 162a2, 162a3, 162a4, and 162a5. Similarly, the five pin holes 142a will be referred to as pin holes 142a1, 142a2, 142a3, 142a4, and 142a5. ru.

[0122] The signals transmitted and received between the base unit 140 and the replacement unit 160 include at least the following five signals. The control unit 601 receives a power supply monitoring signal Sg1 from the SW circuit unit 611 to monitor the power supply status to the replacement unit 160 via connection pin 162a1 and pin hole 142a1. The control unit 601 also receives a connection detection signal Sg2 via connection pin 162a2 and pin hole 142a2 to detect the connection of the replacement unit 160. The control unit 601 also transmits a power supply signal Sg3 via connection pin 162a3 and pin hole 142a3 to switch the SW circuit unit 611 on (closed) and off (open) based on the connection status of the replacement unit 160 to the base unit 140. The light intensity adjustment unit 603, which adjusts the light intensity of the light-emitting element 202, transmits a light-emitting signal Sg4 to the light-emitting circuit board 203 via connection pin 162a4 and pin hole 142a4. Furthermore, the buffer circuit 606 receives the light-receiving signal Sg5, which is the output signal of the light-receiving unit, from the light-receiving circuit board 205 via connection pin 162a5 and pin hole 142a5.

[0123] The five signals described above change based on the attachment / detachment status of the replacement unit 160 and the power supply status determined by the control unit 601. The attachment / detachment detection configuration of the electronic stethoscope 100 detects the attachment / detachment of the replacement unit 160 based on a combination of the states of these five signals.

[0124] Referring to Figure 8, the method for detecting the attachment and detachment of the replacement unit 160 will be explained. Figure 8 is a table showing the status of the electronic stethoscope, illustrating the relationship between the connection status, power supply status, and various signal statuses of the replacement unit 160. Note that each status described below is the state when the power of the electronic stethoscope 100 is turned on.

[0125] State 1, shown in Figure 8, is a state in which the replacement unit 160 is not connected to the base unit 140. In State 1, the power supply monitoring signal Sg1 is Hi (high), indicating that power is not being supplied to the replacement unit 160. The connection detection signal Sg2 is Lo (low), indicating that the replacement unit 160 is not connected to the base unit 140. The power supply signal Sg3 is Lo, which turns off the SW circuit 611, and the SW circuit 611 does not supply power to the connection pin 162a. In State 1, the control unit 601 detects (determines) that the replacement unit 160 is not connected (installed) to the base unit 140. At this time, the light receiving signal Sg5 is Lo.

[0126] State 2, shown in Figure 8, is the state immediately after the replacement unit 160 is connected to the base unit 140. In State 2, the power supply monitoring signal Sg1 remains Hi. On the other hand, the connection detection signal Sg2 becomes Hi, indicating that the replacement unit 160 has been attached to the base unit 140. The power supply signal Sg3 remains Lo. In State 2, the control unit 601 detects that the replacement unit 160 is connected to the base unit 140 and that the base unit 140 and the replacement unit 160 are not conductive (non-conductive). At this time, the light receiving signal Sg5 becomes Lo. Thus, when the control unit 601 detects that the power supply monitoring signal Sg1 is Hi, the connection detection signal Sg2 is Hi, and the power supply signal Sg3 is Lo, it transitions from State 2 to State 3.

[0127] State 3, shown in Figure 8, is the state in which the replacement unit 160 is connected to the base unit 140 and power is supplied from the base unit 140 to the replacement unit 160. To transition from state 2 to state 3, the control unit 601 switches the power supply signal Sg3 from Lo to Hi. Therefore, in state 3, the power supply monitoring signal Sg1 is Lo, indicating that power is being supplied to the replacement unit 160. Also, the connection detection signal Sg2 returns to Lo because the replacement unit 160 is installed on the base unit 140. In addition, the power supply signal Sg3 is switched to Hi, which turns on the SW circuit unit 611. Thus, in state 3 In state 3, the power supply monitoring signal Sg1 is Lo, the connection detection signal Sg2 is Lo, and the power supply signal Sg3 is Hi, which is the opposite logic to state 2. In state 3, the control unit 601 detects that the replacement unit 160 is connected to the base unit 140 and that the base unit 140 and the replacement unit 160 are conductive. At this time, the light receiving signal Sg5 is output (the light receiving signal Sg5 is present).

[0128] When the device enters state 3 and power is supplied to the light-emitting and light-receiving units, the light-receiving unit signal Sg5 is output. Based on the light-receiving unit signal Sg5, the electronic stethoscope 100 can then determine whether or not to perform the calibration described later.

[0129] State 4, shown in Figure 8, is the state immediately after the replacement unit 160 has been removed from the base unit 140. When the replacement unit 160 is removed from the base unit 140, power is no longer supplied to the replacement unit 160. Therefore, when transitioning from state 3 to state 4, the power supply monitoring signal Sg1 switches from Lo to Hi. In other words, in state 4, the power supply monitoring signal Sg1 is Hi, indicating that power is not being supplied to the replacement unit 160. Also, the connection detection signal Sg2 remains Lo, and the power supply signal Sg3 remains Hi. In state 4, the control unit 601 detects that the replacement unit 160 is not connected to the base unit 140. At this time, the light receiving signal Sg5 becomes undefined. When the control unit 601 detects that the power supply monitoring signal Sg1 has switched from Lo to Hi, it transitions from state 4 to state 5.

[0130] State 5, shown in Figure 8, is a state in which the replacement unit 160 has been removed from the base unit 140 and power is not supplied to the replacement unit 160 from the base unit 140. To transition from state 4 to state 5, the control unit 601 switches the power supply signal Sg3 from Hi to Lo and switches the SW circuit unit 611 from On to Off. This is because the replacement unit 160 has been removed from the base unit 140 and no power supply is required. Therefore, in state 5, the power supply monitoring signal Sg1 is Hi, the connection detection signal Sg2 is Lo, and the power supply signal Sg3 is Lo. In other words, state 5 is the same state as state 1. That is, in state 5, the control unit 601 detects that the replacement unit 160 is not connected to the base unit 140.

[0131] In this way, the electronic stethoscope 100 can detect the attachment / detachment operation and connection status of the replacement unit 160 based on the power supply monitoring signal Sg1, the connection detection signal Sg2, and the power supply signal Sg3, and switch the power supply state.

[0132] [Variation of displacement signals] Using Figures 9A and 9B, the variation in the displacement signal, which is the voltage output from the light-receiving circuit board 205, will be illustrated. Graph 410 in Figure 9A shows the relationship between the displacement amount [mm] of the biological surface 320 and the displacement signal [V]. The horizontal axis of graph 410 represents the displacement amount of the biological surface 320 and the displacement signal generated by the light-receiving circuit board 205.

[0133] As described above, the electronic auscultation device 100 is an optical displacement type auscultation device. In such a device, variations occur in the displacement signal, which is the output value, due to mechanical and optical factors. In Figure 9A, the ideal line L1, which shows the ideal relationship between the displacement amount of the biological surface 320 and the displacement signal, is represented by a thick line. Also in Figure 9A, the lines when the relationship between the displacement amount of the biological surface 320 and the displacement signal deviates from the ideal line L1 due to mechanical factors are represented by dotted lines. Due to mechanical factors, the dotted line L2 is where the displacement signal when the displacement amount is zero is greater than the ideal line L1, and the dotted line L3 is where it is smaller. Also in Figure 9A, the lines when the relationship between the displacement amount of the biological surface 320 and the displacement signal deviates from the ideal line L1 due to mechanical and optical factors are represented by dashed lines. Due to mechanical and optical factors, the displacement signal when the displacement amount is zero is greater than the ideal line L1. Let the dashed line be L4, and the smaller dashed line be L5. In this example, the dotted line L2, the dotted line L3, the dashed line L4, and the dashed line L5 are parallel to the ideal line L1.

[0134] Among the factors contributing to the variation in the displacement signal, mechanical factors include dimensional tolerances and assembly tolerances of the components constituting the holding member 201, light-emitting element 202, light-receiving element 204, diaphragm 206, and light-reflecting part 207. Optical factors also contribute to the variation in the displacement signal, including variations in optical characteristics. Variations in optical characteristics include, for example, variations in the light emission characteristics of the light-emitting element 202 (a light-emitting diode) and variations in the light-receiving sensitivity of the light-receiving element 204 (a photosensor). Since the displacement of the biological surface 320 is minute, it is crucial to suppress variations in the displacement signal due to mechanical and optical factors in order to accurately detect vibrations of the biological surface 320.

[0135] One method for suppressing variations in displacement signals due to mechanical factors is to manufacture the electronic stethoscope 100 by assembling each component in a way that corrects assembly tolerances. Graph 420 in Figure 9B shows the relationship between the displacement amount [mm] of the biological surface 320 and the displacement signal [V] when each component is assembled in a way that corrects assembly tolerances. Figure 9B shows the ideal line L1, dotted line L2, dotted line L3, dashed-dotted line L4, and dashed-dotted line L5, similar to Figure 9A.

[0136] Figure 9B shows an example where the position of the diaphragm 206 in the z-axis direction is adjusted so that the output value of the photodetector 204 becomes zero when the displacement of the biological surface 320 is dmax. When the electronic stethoscope 100 is assembled while adjusting the position of the diaphragm 206 in this way, the variation in the displacement signal decreases, and the dotted lines L2, L3, dashed-dotted line L4, and dashed-dotted line L5 approach the ideal line L1. Figure 9B shows an example where the dotted line L2 coincides with the ideal line L1 due to correction during assembly.

[0137] On the other hand, unlike mechanical factors, variations in displacement signals due to optical factors are difficult to correct during assembly. This is because optical factors include variations in the amount of light emitted by the light-emitting element 202 and the amount of light received by the light-receiving element 204 due to individual differences in light-emitting diodes and light sensors, as well as changes in the amount of light emitted due to the aging degradation of the light-emitting element 202. Therefore, the electronic stethoscope 100 is configured to perform calibration to suppress variations in displacement signals due to optical factors, that is, to reduce the difference between the ideal line L1 and the dashed-dotted line L4, and between the ideal line L1 and the dashed-dotted line L5.

[0138] The electronic stethoscope 100 according to the first embodiment corrects the light emission amount of the light-emitting element 202 as a calibration to suppress variations in the displacement signal due to optical factors. The light emission amount is corrected by the control unit 601 transmitting a signal for light intensity correction to the light intensity adjustment unit 603. However, the configuration is not limited to this, and instead of correcting the light emission amount, the configuration may also be such as correcting the light receiving sensitivity of the light-receiving element 204, correcting the power supply voltage of the light-receiving element 204, etc.

[0139] When correcting the light intensity of the light-emitting element 202, the light-emitting circuit board 203 may be configured to allow correction of the light intensity by adjusting the duty cycle of the Pulse Width Modulation (hereinafter referred to as PWM) signal transmitted by the control unit 601. The PWM signal duty cycle refers to the proportion of the signal that is high during one period of the signal waveform. Alternatively, when correcting the light intensity of the light-emitting element 202, the light intensity may be corrected by switching the resistance value of a resistor provided on the light-emitting circuit board 203 in accordance with the signal transmitted by the control unit 601. When correcting the light-receiving sensitivity of the light-receiving element 204, the light-receiving circuit board 205 may be configured to allow correction of the resistance value for converting the output current of the light-receiving element 204 to current / voltage in accordance with the signal transmitted by the control unit 601. Alternatively, when correcting the light-receiving sensitivity of the light-receiving element 204, the light-receiving circuit board 205 may be configured to allow correction of the voltage of the power supply for the light-receiving element 204.

[0140] [Example 1 of the calibration process flow of the first embodiment] Referring to Figure 10, Example 1 of the calibration process flow in the electronic stethoscope 100 will be described. Figure 10 is a flowchart of an example of the calibration process of the electronic stethoscope 100 according to the first embodiment. In Example 1 of the calibration process, the control unit 601 starts the calibration process when the power of the electronic stethoscope 100 is turned on. However, the configuration is not limited to this, and a configuration in which calibration is performed periodically by time management is also possible. For example, a means for acquiring the elapsed time since the replacement unit 160 was attached to the electronic stethoscope 100 may be provided, and a configuration in which calibration is started when the elapsed time exceeds a predetermined threshold may be provided. The calibration process that is started when the power of the electronic stethoscope 100 is turned on will be described below.

[0141] The calibration process flow is preferably performed, for example, with the electronic stethoscope 100 placed on a dedicated stand in a flat state where the diaphragm 206 is not pressed. A dedicated stand on which the electronic stethoscope 100 is placed when not in use or when calibration is being performed, which fixes the gripping part 120, may also be included as a component of the electronic stethoscope 100.

[0142] When the calibration process flow is initiated, the control unit 601 first checks the connection status of the replacement unit 160 in step (hereinafter referred to as S) 1001. More specifically, the control unit 601 checks which of the states 1 to 4 shown in Figure 8 the electronic stethoscope 100 is in, based on the power supply monitoring signal Sg1, the connection detection signal Sg2, and the power supply signal Sg3.

[0143] Next, in S1002, the determination unit 530 determines whether or not the replacement unit 160 is connected to the base unit 140. The determination unit 530 makes the determination based on the connection status checked by the control unit 601 in S1001. If the connection status is state 2 and it is determined that the replacement unit 160 is connected, i.e., if YES in S1002, the process proceeds to S1003. On the other hand, if the connection status is state 1 and it is determined that the replacement unit 160 is not connected, i.e., if NO in S1002, the process proceeds to S1007.

[0144] In S1003, power supply to the replacement unit 160 is initiated. Specifically, the control unit 601 switches the power supply signal Sg3 from Lo to Hi, and switches the electronic stethoscope 100 from state 2 to state 3.

[0145] After power supply is initiated, the determination unit 530 performs a determination in S1004 to determine whether calibration is necessary, i.e., whether calibration is required. The determination of whether calibration is necessary is based on the displacement signal, which is the output result of the photodetector 204. The determination unit 530 determines that calibration is unnecessary if the displacement signal is within a predetermined range, and determines that calibration is necessary if the displacement signal is outside the predetermined range. The upper limit of the predetermined range can be, for example, a value that prevents the displacement signal from saturating at the input of the A / D converter. The lower limit of the predetermined range can be, for example, a value that ensures that an output with sufficient accuracy can be obtained, taking into account the output sensitivity of the photodetector 204.

[0146] If the determination unit 530 determines in S1004 that calibration is necessary, i.e., YES in S1004, the process proceeds to S1005. When it is determined that calibration is necessary, the determination unit 530 transmits a calibration request signal to the control unit 601. Note that the transmission of the calibration request signal is not limited to the determination unit 530; for example, the calibration execution unit 520 may perform the transmission based on the determination result of the determination unit 530. When the level of the calibration request signal becomes Hi, the control unit 601 transmits a light intensity correction signal to perform light intensity correction as a trigger signal to start calibration. In other words, the control unit 601 outputs a trigger signal to start calibration. It functions as a signal output means. However, the function as a trigger signal output means may be provided in a configuration other than the control unit 601.

[0147] In the first embodiment, the light intensity of the light-emitting element 202 is corrected as part of the calibration. After the calibration is performed, the calibration process is terminated. At this time, the normal startup process of the electronic stethoscope 100 may be performed in conjunction with the calibration. The normal startup process may include, for example, displaying the power-on status or the operating mode on the display unit 122. Also, as part of the normal startup process, if the calibration is performed successfully, the user may be notified that the calibration has been performed by displaying it on the display unit 122 or the like. Similarly, as part of the normal startup process, the calibration results, such as the correction amount, may be displayed on the display unit 122 or the like.

[0148] If the determination unit 530 determines in S1004 that calibration is not required, i.e., if the result is NO in S1004, the process proceeds to S1006. In S1006, only the normal startup process is executed without calibration. The calibration process flow then ends without calibration being performed.

[0149] As described above, if it is determined in S1002 that the replacement unit 160 is not connected, the process proceeds to S1007. In S1007, the determination unit 530 determines whether a predetermined time has elapsed from a predetermined timing (for example, the start of the calibration processing flow). To enable the determination unit 530 to acquire the elapsed time, the determination unit 530 may be provided with a counter that starts counting at a predetermined timing, or the elapsed time may be acquired by other means.

[0150] If it is determined in S1007 that the predetermined time has not elapsed, i.e., if the answer to S1007 is NO, the process proceeds back to S1001 and the calibration process continues. On the other hand, if it is determined in S1007 that the predetermined time has elapsed, i.e., if the answer to S1007 is YES, the process proceeds to S1008 to execute a timeout error, as it is determined that the calibration could not be performed. In the case of a timeout error, the power to the electronic stethoscope 100 is turned off, and the calibration process ends. Note that it is not always necessary to turn off the power during a timeout error. For example, the light intensity may be returned to its initial value (the value before light intensity correction), or a message indicating that calibration was not performed may be displayed on the display unit 122, and the power to the electronic stethoscope 100 may remain on.

[0151] [Example 2 of the calibration process flow of the first embodiment] Next, with reference to Figure 11, Example 2 of the calibration process flow in the electronic stethoscope 100 will be described. Figure 11 is a flowchart showing an example of the calibration process of the electronic stethoscope 100 according to the first embodiment. In Example 2 of the calibration process, the control unit 601 starts the calibration process when the calibration button 123d is pressed. The calibration process that is started when the calibration button 123d is pressed will be described below.

[0152] When the calibration processing flow is started, the determination unit 530 first determines in S1101 whether the electronic stethoscope 100, in particular the chestpiece 110, is in a state where calibration can be started. A suitable method for determining whether calibration can be performed (started) is to identify the vibration state or pressure state of the diaphragm 206 and make a determination according to that vibration state or pressure state. Specifically, for example, it may be determined whether the diaphragm 206 is being pressed and displaced. In this case, the amount of displacement of the diaphragm 206 can be obtained based on the displacement signal or biosignal and used for the determination. Alternatively, the determination may be made based on the communication state of each signal, etc. Calibration can be started, i.e., S If the answer to 1101 is YES, proceed to S1102. On the other hand, if calibration cannot be started, i.e., if the answer to S1101 is NO, proceed to S1104.

[0153] In this example, the process assumes that the calibration button 123d is pressed while the electronic stethoscope 100 is powered on. However, the calibration process may also be started when the calibration button 123d is pressed while the power is off. In this case, before the determination of whether or not calibration can be started in S1101, startup processes such as the illumination of the light-emitting element 202 that accompanies power-on are performed.

[0154] In S1102, the determination unit 530 determines whether calibration is necessary, that is, whether calibration is required or not. The determination of whether calibration is necessary in S1102 is the same as the determination of whether calibration is necessary in Example 1 (S1004 in Figure 10). If calibration is necessary, that is, if the answer in S1102 is YES, proceed to S1103. If calibration is not necessary, that is, if the answer in S1102 is NO, proceed to S1104.

[0155] In step S1103, calibration is performed. The calibration in S1103 is the same as the calibration in Example 1 (S1005 in Figure 10). That is, in S1103, the light intensity of the light-emitting element 202 is corrected as part of the calibration. After the calibration is performed, the calibration process is completed.

[0156] If it is determined in S1101 that calibration cannot be started, or if it is determined in S1102 that calibration is unnecessary, the calibration is canceled in S1104. In this example, as part of the calibration cancellation process, the display unit 122 displays a message indicating that calibration was not performed. The display content may be differentiated depending on whether the answer in S1101 was NO or in S1102 was NO.

[0157] If calibration is canceled in S1104, the electronic stethoscope 100 transitions to a ready state in S1105. The ready state is a state in which the electronic stethoscope 100 is capable of auscultation, and examples of auscultation modes include heart sound mode and respiratory sound mode. The calibration process flow then ends without calibration (light intensity correction) being performed.

[0158] [Calibration operation] Referring to Figures 12A and 12B, a specific example of the calibration process (an example of a light intensity correction method) will be explained. In Figures 12A and 12B, the upper graph shows the transition of the displacement signal (contact detection signal), which is the output of the photodetector 204, and the lower graph shows the transition of the calibration request signal. In the graph showing the transition of the displacement signal, the vertical axis is the displacement signal [V] and the horizontal axis is time [seconds]. In the graph showing the transition of the biological signal, the vertical axis is the calibration request (Hi or Lo) and the horizontal axis is time [seconds]. The following explanation will use the calibration process flow shown in Figure 11 (processing initiated when the calibration button 123d is pressed) as an example.

[0159] Figure 12A shows an example of successful calibration. During the period from time t0 to time t1 in Figure 12A, the electronic stethoscope 100 is powered on, but the calibration process has not yet started.

[0160] The period from time t1 to time t2 in Figure 12A is the period during which the user presses the calibration button 123d and the calibration request transitions to Hi. This initiates the calibration process flow shown in Figure 11.

[0161] During the period from time t1 to time t3 in Figure 12A, the calibration feasibility determination in S1101 of Figure 11 is performed. In this example, the diaphragm 206 is not pressed, and it is determined that calibration is possible. Furthermore, from time t2 onward, the calibration request transitions to Lo.

[0162] The period from time t3 to time t4 in Figure 12A is the period during which the determination of whether calibration is necessary (S1102 in Figure 11) is made. In this example, the displacement signal is a constant value from time t0 to time t4, and is outside the predetermined range (greater than the upper limit TU1). Therefore, the determination operation determines that calibration is necessary.

[0163] The period from time t4 to time t5 in Figure 12A is the period during which the light intensity correction, i.e., calibration, shown in S1103 of Figure 11, is performed. During this period, the light intensity of the light-emitting element 202 is corrected, and the displacement signal decreases. In processing example 1, the correction is performed while monitoring the light intensity setpoint and the biological signal through feedback control. When the light intensity of the light-emitting element 202 is corrected to a value within a predetermined range (lower limit TL1 or greater, upper limit TU1 or less), the calibration is completed.

[0164] Figure 12B shows an example where calibration was not performed correctly. During the period from time t0 to time t1 in Figure 12B, the electronic stethoscope 100 is powered on, and the calibration process has not yet started. In this example, the electronic stethoscope 100 is placed with the diaphragm 206 pressed down. Specifically, this could be the case when the electronic stethoscope 100 is placed on an uneven surface such that the chestpiece 110 is facing downwards, or when a component on the surface of the table is in contact with the diaphragm 206. Because the diaphragm 206 is pressed down, the displacement signal value in Example 2 is smaller than the value in Example 1 during the period from time t0 to time t1.

[0165] The period from time t1 to time t2 in Figure 12B is the time when the user presses the calibration button 123d and the calibration request transitions to Hi. This initiates the calibration processing flow shown in Figure 11. After time t2, the calibration request transitions to Lo.

[0166] During the period from time t1 to time t3 in Figure 12B, the calibration feasibility determination in S1101 of Figure 11 is performed. When the calibration button 123d is pressed, the chestpiece 110 is pushed from above, and the positional relationship between the aperture 210 and the diaphragm 206 changes due to the elastic deformation of the housing 208, etc. As a result, some of the reflected light hits the aperture 210 and does not reach the photodetector 204, causing the displacement signal to fluctuate. In other words, since the displacement signal is not a constant value but is constantly fluctuating during the period from time t1 to time t3, the diaphragm 206 is in an unstable state, and it is determined that calibration is not feasible. Then, the calibration cancellation process in S1104 of Figure 11 is performed.

[0167] In this way, when the diaphragm 206 is pressed, calibration is not performed or is canceled, thereby preventing incorrect corrections from being made and reducing the accuracy of the output result. Furthermore, if the calibration process is canceled, the display unit 122 may be configured to display a message to the user indicating that they should check the status of the diaphragm 206.

[0168] In the examples shown in Figures 12A and 12B, the light intensity was corrected by feedback control, but the correction method is not limited to this. For example, the correction amount may always be a constant value, and the correction may be performed repeatedly. Alternatively, the first correction may be performed by a fixed amount, and the correction amount may be determined based on the light intensity setpoint and the biological signal value before and after the correction.

[0169] [Example 3 of the calibration process flow of the first embodiment] Next, with reference to Figure 13, Example 3 of the calibration process flow in the electronic stethoscope 100 will be described. Figure 13 is a flowchart of an example of the calibration process of the electronic stethoscope 100 of the first embodiment. In calibration process example 3, the control unit 601 starts the calibration process when the replacement unit 160 is installed. More specifically, in this example, the calibration process flow starts when the electronic stethoscope 100 transitions from state 2 to state 3 shown in Figure 8. The calibration process that starts when the replacement unit 160 is installed (replaced) will be described below.

[0170] When the calibration process is initiated, the electronic stethoscope 100 is in state 3, so the replacement unit 160 is mounted on the base unit 140 and power is supplied to the replacement unit 160.

[0171] When the calibration process is started, the determination unit 530 determines whether the electronic stethoscope 100, particularly the chestpiece 110, is in a state where calibration can be started. The method for determining whether calibration can be started in S1301 is the same as the method for determining whether calibration can be started in Example 2 (S1101 in Figure 11). If calibration can be started, i.e., if S1301 is YES, the process proceeds to S1302. On the other hand, if calibration cannot be started, i.e., if S1301 is NO, the process proceeds to S1303.

[0172] In S1302, calibration is performed. The calibration in S1302 is the same as the calibration in Example 1 and Example 2 (S1005 in Figure 10 and S1103 in Figure 11). That is, in S1302, the light intensity of the light-emitting element 202 is corrected as part of the calibration. After the calibration is performed, the calibration process is completed.

[0173] Thus, in Example 3, calibration is performed without determining whether calibration is necessary. When the replacement unit 160 is replaced, or when the need for calibration (correction) is considered high, the system may be configured to perform calibration only after determining whether calibration is feasible.

[0174] In S1303, the calibration is canceled. Then, the process proceeds to S1304 without performing the calibration. At this point, for example, processing may be performed to set the light intensity setting to a predetermined default value.

[0175] In S1304, an error is displayed on the display unit 122. The display may simply indicate that the calibration was not performed correctly. Alternatively, it may prompt the user to perform the calibration again or to remove and install the replacement unit 160. Furthermore, if the calibration is not performed correctly, the system may be configured not to switch to auscultation mode. After the error is displayed, the calibration process is terminated.

[0176] [Example 4 of the calibration process flow of the first embodiment] Next, with reference to Figure 14, Example 4 of the calibration process flow in the electronic auscultation device 100 will be described. Figure 14 is a flowchart showing an example of the calibration process of the electronic auscultation device 100 of the first embodiment. In Calibration Process Example 4, the calibration process is started when the device switches from power-saving mode to auscultation mode. The calibration process that is started upon returning from power-saving mode will be described below.

[0177] The basic processing steps in Example 4 are the same as those in Example 1. Specifically, steps S1401 to S1406 in Example 4 are the same as steps S1001 to S1006 in Example 1. Below, we will only explain the differences between the processing flow of Example 4 (Figure 14) and Example 1 (Figure 10).

[0178] If it is determined in S1402 that the replacement unit 160 is not connected to the base unit 140, the process proceeds to S1407. In S1407, an error message is displayed on the display unit 122. The message can be either text or the illumination of a designated lamp, as long as it informs the user that the replacement unit 160 is not properly installed. After a predetermined time has elapsed, the process returns to S1401, and the connection status of the replacement unit 160 is checked again.

[0179] In this example 4, the system is configured to continue displaying an error if the replacement unit 160 is not properly connected. In other words, the calibration process flow will not end until the user properly connects the base unit 140 and the replacement unit 160, or until the user forcibly turns off the power to the electronic stethoscope 100, without the power being turned off.

[0180] As shown in Examples 1 to 4, the calibration process flow can be started when various predetermined execution conditions are met (triggered by a predetermined action). Furthermore, the processing content may differ depending on the predetermined execution conditions. The predetermined execution conditions are, in Example 1, turning on the power of the electronic stethoscope 100; in Example 2, pressing the calibration button 123d; in Example 3, attaching the replacement unit 160; and in Example 4, returning from power-saving mode. By configuring the system so that calibration is started when predetermined execution conditions are met, calibration can be performed periodically, thereby suppressing a decrease in the detection accuracy of displacement and vibration of the biological surface 320.

[0181] <Other Embodiments> The configurations shown in each of the embodiments described above can be combined as needed. The present invention can also be realized by supplying a program that implements one or more of the functions of the embodiments described above to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0182] This embodiment includes the following configuration. (Composition 1) A detection device for detecting vibrations of a target, A diaphragm having a reflective surface that moves in response to the vibration of the object to be detected, A light-emitting unit that emits light toward the reflective surface, A light receiving unit that receives light reflected by the reflective surface and outputs a signal corresponding to the light, A diaphragm unit that narrows the light emitted by the light-emitting unit before it reaches the light-receiving unit, Calibration execution means for performing at least one of the following as calibration: correction of the light intensity of the light-emitting part and correction of the light-receiving sensitivity of the light-receiving part. A control unit that starts a calibration process flow for performing the calibration when predetermined execution conditions are met, A detection device characterized by comprising the following features. (Configuration 2) The detection device according to configuration 1, characterized in that the predetermined execution condition includes turning on the power of the detection device. (Composition 3) It further includes a calibration button for performing the aforementioned calibration, The detection device according to configuration 1 or 2, characterized in that the predetermined execution condition includes pressing the calibration button. (Composition 4) A replacement unit including the diaphragm, the light-emitting part, the light-receiving part, and the aperture part, The base unit is configured to be detachable from the aforementioned replacement unit, Furthermore, The detection device according to any one of configurations 1 to 3, characterized in that the predetermined execution conditions include mounting the replacement unit to the base unit. (Composition 5) The system further includes a connection part provided on the replacement unit and a second connection part provided on the base unit that is electrically connected to the first connection part, The detection device according to configuration 4, characterized in that the attachment / detachment detection configuration detects the connection state of the replacement unit to the base unit based on the connection state of the first connection part and the second connection part. (Composition 6) The attachment / detachment detection configuration further includes a control unit provided in the base unit, which transmits and receives a plurality of signals to and from the exchange unit via the first connection part and the second connection part, The detection device according to configuration 5, characterized in that the attachment / detachment detection configuration detects that the replacement unit has been attached to the base unit based on the plurality of signals. (Composition 7) The detection device according to configuration 6, characterized in that the plurality of signals include a power supply monitoring signal for monitoring the power supply status of the replacement unit, a connection detection signal for detecting the connection of the replacement unit to the base unit, and a power supply signal for switching the power supply to the replacement unit on and off based on the connection status of the replacement unit to the base unit. (Composition 8) The detection device according to any one of configurations 5 to 7, characterized in that one of the first connection portion and the second connection portion includes a plurality of connection pins, and the other includes a plurality of pin holes into which the connection pins are inserted. (Composition 9) The detection device is configured to be switchable between a detection mode in which the light-emitting unit emits light and the light-receiving unit outputs the signal, and a power-saving mode in which power consumption is lower than that of the detection mode. The detection device according to any one of the configurations 1 to 8, characterized in that the predetermined execution condition is switching the detection device from the power-saving mode to the detection mode. (Composition 10) The detection device according to any one of the configurations 1 to 9, characterized in that the calibration processing flow includes a determination of whether or not the calibration can be performed. (Composition 11) The detection device according to any one of the configurations 1 to 10, characterized in that the calibration processing flow includes a determination of whether or not calibration is necessary. (Composition 12) The detection device according to any one of the configurations 4 to 8, characterized in that the calibration processing flow includes determining whether the replacement unit is properly connected to the base unit. (Composition 13) The signal output by the light receiving unit is the area of ​​the light irradiation region formed by specularly reflected light reaching the light receiving unit, and the light irradiation region changes according to the displacement of the reflective surface of the diaphragm. A detection device according to any one of the configurations 1 to 12, characterized in that it changes according to the area of ​​the region. (Composition 14) A detection device described in any one of configurations 1 to 13, A sound output unit that outputs a signal to a sound output device to emit sound based on the signal generated by the detection device, An electronic stethoscope characterized by being equipped with the following features. (Composition 15) The electronic auscultation device according to configuration 14, characterized in that the sound output unit includes a filter for filtering the signal output by the light receiving unit and an amplifier for amplifying the signal. [Explanation of symbols]

[0183] 100...Electronic stethoscope, 110...Chestpiece, 206...Diaphragm, 209...Constrictor, 210...Constrictor

Claims

1. A detection device for detecting vibrations of a target, A diaphragm having a reflective surface that moves in response to the vibration of the object to be detected, A light-emitting unit that emits light toward the reflective surface, A light receiving unit that receives light reflected by the reflective surface and outputs a signal corresponding to the light, A diaphragm unit that narrows the light emitted by the light-emitting unit before it reaches the light-receiving unit, Calibration execution means for performing at least one of the following as calibration: correction of the light intensity of the light-emitting part and correction of the light-receiving sensitivity of the light-receiving part. A control unit that starts a calibration process flow for performing the calibration when predetermined execution conditions are met, A detection device characterized by comprising the following features.

2. The detection device according to claim 1, characterized in that the predetermined execution condition includes turning on the power of the detection device.

3. It further includes a calibration button for performing the aforementioned calibration, The detection device according to claim 1, characterized in that the predetermined execution condition includes pressing the calibration button.

4. A replacement unit including the diaphragm, the light-emitting part, the light-receiving part, and the aperture part, The base unit is configured to be detachable from the aforementioned replacement unit, Furthermore, The detection device according to claim 1, characterized in that the predetermined execution conditions include mounting the replacement unit to the base unit.

5. The system further includes a connection part provided on the replacement unit and a second connection part provided on the base unit that is electrically connected to the first connection part, The detection device according to claim 4, characterized in that the attachment / detachment detection configuration detects the connection state of the replacement unit to the base unit based on the connection state of the first connection part and the second connection part.

6. The attachment / detachment detection configuration further includes a control unit provided in the base unit, which transmits and receives a plurality of signals to and from the exchange unit via the first connection part and the second connection part, The detection device according to claim 5, characterized in that the attachment / detachment detection configuration detects that the replacement unit has been attached to the base unit based on the plurality of signals.

7. The detection device according to claim 6, characterized in that the plurality of signals include a power supply monitoring signal for monitoring the power supply status of the replacement unit, a connection detection signal for detecting the connection of the replacement unit to the base unit, and a power supply signal for switching the power supply to the replacement unit on and off based on the connection status of the replacement unit to the base unit.

8. The detection device according to claim 5, characterized in that one of the first connection portion and the second connection portion includes a plurality of connection pins, and the other includes a plurality of pin holes into which the connection pins are inserted.

9. The detection device is configured to be switchable between a detection mode in which the light-emitting unit emits light and the light-receiving unit outputs the signal, and a power-saving mode in which power consumption is lower than that of the detection mode. The detection device according to claim 1, characterized in that the predetermined execution condition is switching the detection device from the power-saving mode to the detection mode.

10. The detection device according to claim 1, characterized in that the calibration processing flow includes a determination of whether or not the calibration can be performed.

11. The detection device according to claim 1, characterized in that the calibration processing flow includes a determination of whether or not calibration is necessary.

12. The detection device according to claim 4, characterized in that the calibration processing flow includes determining whether the replacement unit is properly connected to the base unit.

13. The detection device according to claim 1, wherein the signal output by the light receiving unit is the area of ​​the light-irradiated region formed by specularly reflected light reaching the light receiving unit, and changes in accordance with the area of ​​the light-irradiated region which changes in accordance with the displacement of the reflective surface of the diaphragm.

14. A detection device according to any one of claims 1 to 13, A sound output unit that outputs a signal to a sound output device to emit sound based on the signal generated by the detection device, An electronic stethoscope characterized by being equipped with the following features.

15. The electronic auscultation device according to claim 14, characterized in that the sound output unit includes a filter for filtering the signal output by the light receiving unit and an amplifier for amplifying the signal.

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