Wearable device

Abstract

Provided is a wearable device capable of stably measuring biological information of a living body and causing little irritation to the surface of an arm.　The wearable device comprises: a body that is mounted on a surface of an arm of a living body and that has a base surface facing the surface; a band body that is mounted on the arm; and a plurality of electrodes that measure biological information of the living body from the surface. The plurality of electrodes include at least two electrodes arranged on opposite sides of a longitudinal intermediate line in a bottom view. Each of the plurality of electrodes has a contact surface located below the base surface. The body has a plurality of frame portions surrounding the plurality of electrodes and a first groove portion extending along the longitudinal intermediate line. The plurality of electrodes are respectively surrounded by the plurality of frame portions while being spaced apart from each other. The first groove portion has a groove bottom surface and a pair of groove side surfaces. The groove side surfaces of the first groove portions are formed by the frame portions, among the plurality of frame portions, arranged on opposite sides of the longitudinal intermediate line.

Description

Wearable device

[0001] The present disclosure relates to a wearable device.

[0002] Wearable devices that are worn on the surface of a living body's arm are known (see, for example, Patent Documents 1 and 2). The wearable device described in Patent Document 1 includes a plurality of electrodes that measure biological information from the surface of a living body.

[0003] Japanese Patent Application Laid-Open No. 2024-110290 Japanese Patent No. 7073772

[0004] In the wearable device described in Patent Document 1, an electrode that comes into contact with the surface of the arm is fixed in a state where a part of the electrode protrudes from the bottom surface of the main body housing. This ensures that the contact surface of the electrode reliably contacts the surface of the wearer's arm, but contact of the side surface of the electrode with the arm surface that is raised due to pressing of the electrode is not suppressed. For this reason, the contact area of the electrode that contacts the arm surface changes greatly depending on how the electrode is pressed against the arm surface, which may make it impossible to measure accurate biological information.

[0005] Accordingly, an object of the present disclosure is to provide a wearable device that can stably measure biological information.

[0006] One aspect of the present disclosure is as follows.

[0007] [Item 1] A wearable device to be attached to the surface of a living arm, comprising: a main body having a base surface facing the surface of the arm; a band connected to the main body, extending from the main body to define the longitudinal direction of the wearable device, and positioned along the surface of the arm such that the longitudinal direction is along the circumferential direction of the arm, thereby being attached to the arm; and a plurality of electrodes positioned within the base surface in a bottom view for measuring biological information of the living body from the surface of the living body, wherein the plurality of electrodes have at least two electrodes positioned on either side of a longitudinal midline passing through the center of the base surface in the longitudinal direction and perpendicular to the longitudinal direction in a bottom view, each of the plurality of electrodes protrudes such that the contact surface with the surface of the arm is located below the base surface, and the main body has a plurality of frame portions surrounding the plurality of electrodes in a bottom view and protruding downward from the base surface, and a first groove portion extending along the longitudinal midline, Each of the plurality of electrodes is surrounded by the plurality of frame portions at intervals from each other when viewed from the bottom, and the first groove portion has a groove bottom surface formed by the base surface and a pair of groove side surfaces arranged on either side of the longitudinal midline, and the pair of groove side surfaces of the first groove portion is formed by at least two of the plurality of frame portions arranged on either side of the longitudinal midline, in a wearable device.

[0008] [Item 2] The wearable device according to Item 1, wherein the protruding length L of each of the plurality of frame portions from the base surface is equal to or less than the height H from the base surface to the contact surface of the electrode surrounded by the frame portion among the plurality of electrodes.

[0009] [Item 3] The wearable device according to item 1 or 2, wherein the projection length L of each of the plurality of frame portions from the base surface is 30 to 95% of the height H from the base surface to the contact surface of the electrode surrounded by the frame portion among the plurality of electrodes.

[0010] [Item 4] The wearable device according to any one of items 1 to 3, wherein the height H from the base surface to the contact surface of each of the plurality of electrodes is 0.5 to 1.5 mm.

[0011] [Item 5] The wearable device according to any one of items 1 to 4, wherein, in a view from the bottom, the width W of the frame portion in the direction from the outer peripheral edge of the contact surface of each of the surrounding plurality of electrodes toward the outer edge of the base surface is 0.5 to 1.5 mm.

[0012] [Clause 6] The wearable device according to any one of Clauses 1 to 5, wherein the plurality of electrodes have electrodes positioned with respect to at least two electrodes, straddling a midline in the short direction perpendicular to the short direction, passing through the center of the base surface in the short direction perpendicular to the longitudinal direction in a bottom view, the body has a second groove extending along the midline in the short direction, the second groove has a groove bottom surface formed by the base surface and a pair of groove sides positioned straddling the midline in the short direction, and the pair of groove sides of the second groove are formed by at least two frame portions of the frame portion positioned straddling the midline in the short direction.

[0013] [Clause 7] A wearable device according to any one of Clauses 1 to 6, comprising a pulse wave sensor disposed in the first groove in a bottom view for measuring pulse waves from the surface of the arm.

[0014] [Clause 8] The wearable device according to any one of Clauses 1 to 7, wherein the plurality of electrodes comprises a pair of application electrodes for applying a voltage to the surface of the arm, and a pair of detection electrodes for detecting a voltage or current between the pair of application electrodes.

[0015] [Clause 9] The wearable device according to Clause 8, wherein the pair of application electrodes are arranged on either side of the longitudinal midline in the bottom view, and the pair of detection electrodes are arranged on either side of the longitudinal midline in the bottom view.

[0016] [Clause 10] The wearable device according to Clause 9, wherein one of the pair of application electrodes is positioned with respect to one of the pair of detection electrodes, with respect to a midline in the short direction perpendicular to the longitudinal direction, passing through the center of the base surface in the short direction perpendicular to the longitudinal direction in a bottom view, and the other of the pair of application electrodes is positioned with respect to the midline in the short direction in a bottom view.

[0017] [Clause 11] The wearable device according to Clause 10, wherein the plurality of frame portions have four frame portions that separately surround the pair of application electrodes and the pair of detection electrodes, the main body has a second groove portion extending along the midline in the short direction, the second groove portion has a groove bottom surface formed by the base surface and a pair of groove side surfaces arranged on either side of the midline in the short direction, and the pair of groove side surfaces of the first groove portion and the pair of groove side surfaces of the second groove portion are each formed by the four frame portions.

[0018] [Clause 12] The wearable device according to Claim 10 or 11, wherein the plurality of frames comprises: a first frame surrounding two electrodes of the plurality of electrodes arranged on one side of the longitudinal midline with respect to the short midline; and a second frame surrounding two electrodes of the plurality of electrodes arranged on the other side of the longitudinal midline with respect to the short midline, wherein the first frame extends along the short midline such that the two electrodes arranged on one side of the longitudinal midline with respect to the short midline are adjacent to each other via the first frame, and the second frame extends along the short midline such that the two electrodes arranged on the other side of the longitudinal midline with respect to the short midline are adjacent to each other via the second frame.

[0019] [Item 13] The wearable device according to any one of items 1 to 12, wherein the biological information of the living organism is bioelectrical impedance.

[0020] [Item 14] The main body has a housing, the housing has a bottom wall facing the surface of the arm, the band is provided to extend from the housing and is wrapped around the arm, the pulse wave sensor is a photoelectric pulse wave sensor, the photoelectric pulse wave sensor has a light-emitting part, a light-receiving part and a window, the window is light-transmitting and forms part of the bottom wall, the light-emitting part and the light-receiving part are each provided inside the housing, the bottom wall has ribs on both sides and extending parts on both sides, the ribs on both sides consist of a pair of ribs, the pair of ribs are provided on both sides of the window in the longitudinal direction, each of the pair of ribs protrudes from the lower surface of the bottom wall to below the extending parts on both sides and extends in the short direction perpendicular to the longitudinal direction in the bottom view, in the short direction, the range in which the pair of ribs extend each includes the range in which the window extends, and the extending parts on both sides consist of a pair of extending parts. The wearable device according to claim 7, wherein the pair of extending portions are provided on both sides of the window portion in the short direction, each of the pair of extending portions extends in the longitudinal direction, and in the longitudinal direction, the range to which each of the pair of extending portions extends includes the range to which the window portion extends.

[0021] [Item 15] The wearable device according to item 14, wherein the photoelectric pulse wave sensor has a light-shielding wall, the light-shielding wall is provided inside the housing and surrounds the light-receiving unit but does not surround the light-emitting unit.

[0022] [Clause 16] The wearable device according to Clause 15, wherein in the cross section perpendicular to the longitudinal direction, the distance along the short direction from the outer edge of the window portion to the light-emitting portion is 1.0 to 4.5 mm.

[0023] [Clause 17] The wearable device according to Clause 15 or 16, wherein the distance along the vertical direction from the light-receiving portion to the lower surface of the window portion in a cross section perpendicular to the longitudinal direction is defined as the first distance, the distance along the short direction from the light-receiving portion to the outer edge of the window portion in a cross section perpendicular to the longitudinal direction is defined as the second distance, and the distance along the vertical direction from the light-receiving portion to the lower surface of the light-shielding wall in a cross section perpendicular to the longitudinal direction is defined as the third distance, and when the units of the first distance, the second distance and the third distance are mm, the value obtained by dividing the second distance by the first distance is 8 times or more and 12 times or less of the third distance.

[0024] [Clause 18] A wearable device according to any one of Clauses 14 to 17, comprising a first electrode and a second electrode for measuring biological information of the living organism from the surface of the arm, wherein the first electrode is surrounded by one of the pair of ribs and the second electrode is surrounded by the other of the pair of ribs.

[0025] According to this disclosure, it is possible to provide a wearable device capable of stably measuring the biological information of living organisms.

[0026] This is a side view of the body of a wearable device according to the first embodiment of this disclosure, viewed along the short side. This is a bottom view of the wearable device of Figure 1. This is a cross-sectional view taken along line A-A in Figure 2. This is a cross-sectional view taken along line B-B in Figure 2. This is a bottom view of a first modified wearable device. This is a bottom view of a second modified wearable device. This is a bottom view of a third modified wearable device. This is a bottom view of a fourth modified wearable device. This is a partial cross-sectional view showing a wearable device according to the second embodiment of this disclosure. This is a bottom view of the wearable device shown in Figure 9. This is a cross-sectional view taken along line C-C in Figure 10.

[0027] The embodiments of this disclosure will be described in detail below with reference to the drawings.

[0028] As shown in Figure 1, the wearable device 101 according to the first embodiment of this disclosure is attached to the surface of the arm 5 of a living organism (e.g., a person) (e.g., the surface of the wrist).

[0029] As shown in Figures 1 and 2, the wearable device 101 comprises a main body 102, a band 103, and a plurality of electrodes 104. The main body 102 has a base surface 102a facing the surface of the arm 105. The band 103 is connected to the main body 102, extends from the main body 102 to define the longitudinal direction of the wearable device 101, and is positioned along the surface of the arm 105 so that its longitudinal direction aligns with the circumferential direction of the arm 105, thereby being attached to the arm 105. The plurality of electrodes 104 are positioned within the base surface 102a when viewed from below and measure biological information of the living body from the surface of the living body.

[0030] The wearable device 101 measures bioelectrical impedance, which is biological information of the living body, and enables the calculation of the water content of the arm 105 based on the measured bioelectrical impedance. This makes it possible to detect edema in the living body. For example, it is known that when the living body's cardiac function or renal function declines, edema occurs, in which fluid accumulates in or under the skin. With the wearable device 101, by calculating the water content of the arm 105 of a user who has heart disease or kidney disease, etc., a decline in cardiac function or renal function can be detected early. Also, it is known that when the flow of lymphatic fluid in a patient decreases due to breast cancer treatment, edema occurs, in which fluid accumulates in or under the skin of the treated upper limb. With the wearable device 101, by calculating the water content of the arm 105 of a user who has breast cancer, breast cancer-related lymphedema can be detected early.

[0031] The plurality of electrodes 104 have at least two electrodes 104 positioned on either side of a longitudinal midline O that passes through the center of the base surface 102a in the longitudinal direction and is perpendicular to the longitudinal direction when viewed from the bottom. Each of the plurality of electrodes 104 protrudes such that the contact surface 104a with the surface of the arm 105 is located below the base surface 102a.

[0032] In this embodiment, the direction perpendicular to the base surface 102a is called the up-down direction, the direction along the up-down direction from the main body 102 toward the living body is called the down direction, and the opposite direction is called the up direction. The up-down direction is perpendicular to the longitudinal direction and the short direction.

[0033] The main body 102 has a plurality of frame portions 102b that surround a plurality of electrodes 104 in a bottom view and protrude downward from the base surface 102a, and a first groove portion 102c that extends along the longitudinal midline O. Each of the plurality of electrodes 104 is surrounded by the plurality of frame portions 102b with a distance between them in a top view. As shown in Figure 3, the first groove portion 102c has a groove bottom surface 102c1 formed by the base surface 2a, and a pair of groove side surfaces 102c2 arranged on either side of the longitudinal midline O. The pair of groove side surfaces 102c2 of the first groove portion 102c is formed by at least two of the plurality of frame portions 102b arranged on either side of the longitudinal midline O.

[0034] According to the above configuration, each of the multiple electrodes 104 is surrounded by multiple frame portions 102b, with each electrode spaced apart from the others when viewed from below, and with the contact surface 104a with respect to the surface of the arm 105 protruding so that it is located below the base surface 102a. This allows for stable contact of the contact surface 104a with the surface of the arm 105, while suppressing contact of the electrode side surfaces 104b with the surface of the arm 105, which may be raised by the pressure applied by the multiple electrodes 104. Therefore, the contact area of ​​each of the multiple electrodes 104 with the surface of the arm 105 is suppressed from changing significantly depending on the degree of pressure applied by the contact surface 104a with the surface of the arm 105, enabling stable measurement of bioelectrical impedance, which is biological information of the living body. In addition, the multiple frame portions 102b also suppress displacement or detachment of the electrodes 104 due to contact of an external object with the corner formed by the outer edge of the contact surface 104a and the electrode side surface 104b of each of the multiple electrodes 104.

[0035] The protrusion length L (see Figure 3) of each of the multiple frame portions 102b from the base surface 102a is the same as, or less than, the height H (see Figure 3) from the base surface 102a to the contact surface 104a of the electrode 104 surrounded by the frame portion 102b among the multiple electrodes 104. With the above configuration, when the multiple electrodes 104 are pressed against the surface of the arm 105, the contact surface 104a can be made to contact the surface of the arm 105 more stably. Therefore, bioelectrical impedance, which is biological information of the living body, can be measured more stably.

[0036] From the viewpoint of obtaining the above effects, it is preferable that the protrusion length L (see Figure 3) of each of the multiple frame portions 102b from the base surface 102a is 30 to 95% of the height H (see Figure 3) from the base surface 102a to the contact surface 104a of the electrode 104 surrounded by the frame portion 102b among the multiple electrodes 104. This allows the contact surface 104a to make more stable contact with the surface of the arm 105 when the multiple electrodes 104 are pressed against the surface of the arm 105. Therefore, bioelectrical impedance, which is biological information of the living body, can be measured more stably.

[0037] Furthermore, the protrusion length L (see Figure 3) of each of the multiple frame portions 102b from the base surface 102a may exceed the height H (see Figure 3) from the base surface 102a to the contact surface 104a of the electrode 104 surrounded by the frame portion 102b, but may be 110% or less of the height H. This further suppresses displacement or detachment of the electrode 104 due to contact of an external object with the corner formed by the outer edge of the contact surface 104a and the electrode side surface 104b of each of the multiple electrodes 104. Even with this configuration, the contact of the electrode side surface 104b with the surface of the arm 105, which is raised by the pressing of the multiple electrodes 104, can be suppressed by the multiple frame portions 102b. Therefore, the contact area of ​​each of the multiple electrodes 104 with the surface of the arm 105 is suppressed from changing significantly depending on the degree of pressure applied by the contact surface 104a to the surface of the arm 105. Consequently, bioelectrical impedance, which is biological information of the living body, can be measured stably.

[0038] From the viewpoint of obtaining the above effects, the height H from the base surface 102a to the contact surface 104a of each of the multiple electrodes 104 is preferably 0.5 to 1.5 mm.

[0039] From the viewpoint of obtaining the above effects, it is preferable that the width W (see Figure 3) of the frame portion 102b in the direction from the outer peripheral edge of the contact surface 104a of each of the surrounding electrodes 104 toward the outer edge of the base surface 102a, when viewed from the bottom, is 0.5 to 1.5 mm.

[0040] The multiple electrodes 104 have electrodes positioned with respect to at least two of the electrodes 104, with a short-axis intermediate line P passing through the center of the base surface 102a in the short-axis direction perpendicular to the longitudinal direction when viewed from below. The main body 102 has a second groove 102d extending along the short-axis intermediate line P. As shown in Figure 4, the second groove 102d has a groove bottom surface 102d1 formed by the base surface 102a and a pair of groove sides 102d2 positioned on either side of the short-axis intermediate line P. The pair of groove sides 102d2 of the second groove 102d are formed by at least two frame portions 102b of the frame portion 102b positioned on either side of the short-axis intermediate line P. The first groove 102c and the second groove 102d intersect at the center of the base surface 102a, forming a cross shape when viewed from below.

[0041] The wearable device 101 has a pulse wave sensor 106 positioned in the first groove 102c when viewed from the bottom, which measures pulse wave information (pulse wave signal) on the surface of the arm 105. The pulse wave sensor 106 is an optical pulse wave sensor that utilizes, for example, photoplethysmography (PPG).

[0042] Each of the electrodes 104 has a pair of application electrodes 107 that apply a voltage to the surface of the arm 105, and a pair of detection electrodes 108 that detect the voltage or current between the pair of application electrodes 107. The pair of application electrodes 107 are arranged on either side of the longitudinal midline O when viewed from below. The pair of detection electrodes 108 are arranged on either side of the longitudinal midline O when viewed from below. One of the pair of application electrodes 107 is positioned on either side of the short midline P when viewed from below with the other of the pair of detection electrodes 108. The other of the pair of application electrodes 107 is positioned on either side of the short midline P when viewed from below with the other of the short midline P when viewed from below with the other of the pair of detection electrodes 108.

[0043] Bioelectrical impedance is measured by calculation based on the voltage or current detected by the pair of detection electrodes 108. In order to improve measurement accuracy, not only is a voltage applied by the pair of application electrodes 107, but voltage or current is also detected, and bioelectrical impedance is measured based on the voltage or current detected by these four electrodes. Note that bioelectrical impedance may be simply calculated based only on the voltage or current detected by the pair of detection electrodes 108.

[0044] As in the first modification shown in FIG. 5, the plurality of electrodes 104 may have only the pair of application electrodes 107, and may be configured such that not only a voltage is applied by the pair of application electrodes 107, but voltage or current is also detected. In this case also, bioelectrical impedance can be simply calculated.

[0045] As in the second modification shown in FIG. 6 and the third modification shown in FIG. 7, the plurality of electrodes 104 may have only the pair of application electrodes 107 and one detection electrode 108, and may be configured such that one of the pair of application electrodes 107 and the one detection electrode 108 detect voltage or current. In this case also, bioelectrical impedance can be simply calculated.

[0046] The pair of application electrodes 107 may be arranged so as to sandwich the lateral center line P when viewed from the bottom surface. The pair of detection electrodes 108 may be arranged so as to sandwich the lateral center line P when viewed from the bottom surface. In this case, one of the pair of application electrodes 107 may be arranged with one of the pair of detection electrodes 108 so as to sandwich the longitudinal center line O when viewed from the bottom surface, and the other of the pair of application electrodes 107 may be arranged with the other of the pair of detection electrodes 108 so as to sandwich the longitudinal center line O when viewed from the bottom surface. In this case, as in the third modification shown in FIG. 7, a configuration may be adopted in which one detection electrode 108 is provided instead of the pair of detection electrodes 108.

[0047] As shown in FIG. 2, the plurality of frame portions 102b include four frame portions 102b that separately surround the pair of application electrodes 107 and the pair of detection electrodes 108. The pair of groove side surfaces 102c2 of the first groove portion 102c and the pair of groove side surfaces 102d2 of the second groove portion 102d are each formed by the four frame portions 102b.

[0048] Note that, as in the fourth modification shown in FIG. 8, the plurality of frame portions 102b include: a first frame portion 102b3 surrounding two electrodes 104 arranged with the lateral intermediate line P interposed therebetween on one side with respect to the longitudinal intermediate line O among the plurality of electrodes 104; and a second frame portion 102b4 surrounding two electrodes 104 arranged with the lateral intermediate line P interposed therebetween on the other side with respect to the longitudinal intermediate line O among the plurality of electrodes 104. The first frame portion 102b3 may extend along the lateral intermediate line P such that the two electrodes 104 arranged with the lateral intermediate line P interposed therebetween on one side with respect to the longitudinal intermediate line O are adjacent to each other via the first frame portion 102b3, and the second frame portion 102b4 may extend along the lateral intermediate line P such that the two electrodes 104 arranged with the lateral intermediate line P interposed therebetween on the other side with respect to the longitudinal intermediate line O are adjacent to each other via the second frame portion 102b4.

[0049] The contact surface 104a has a pair of sides extending in the longitudinal direction and a pair of sides extending in the lateral direction when viewed from the bottom, and forms a substantially rectangular shape with four rounded corners. The base surface 102a has a planar shape perpendicular to the vertical direction. In each of the plurality of electrodes 104, the contact surface 104a has a planar shape parallel to the base surface 102a.

[0050] Each of the plurality of electrodes 104 has an electrode side surface 104b extending along the vertical direction and continuing to the outer peripheral edge of the contact surface 104a. In each of the plurality of electrodes 104, the corner between the electrode side surface 104b and the contact surface 104a is rounded, and the lower end of the electrode side surface 104b smoothly continues to the outer peripheral edge of the contact surface 104a.

[0051] Each of the multiple frame portions 102b has a lower end 102b1 located below the base surface 102a and adjacent to the outer peripheral edge of the contact surface 104a when viewed from the bottom, and an outer peripheral surface 102b2 that connects the outer peripheral edge of the lower end 102b1 to the base surface 102a. In each of the multiple frame portions 102b, the lower end 102b1 has a lower end surface that is planar and parallel to the base surface 102a. The outer peripheral surface 102b2 extending along the first groove portion 102c forms the groove side surface 102c2 of the first groove portion 102c. The outer peripheral surface 102b2 extending along the second groove portion 102d forms the groove side surface 102d2 of the second groove portion 102d.

[0052] In this embodiment, in each of the multiple frame portions 102b, the outer peripheral surface 102b2 extends smoothly upward and radially outward from the lower end 102b1 to the base surface 102a. This suppresses contact between the surface of the arm 105 and the corners formed by the outer peripheral edge of the contact surface 104a and the electrode side surface 104b of each of the multiple electrodes 104, and since the multiple frame portions 102b themselves do not apply a localized load to the surface of the arm 105, the irritation to the surface of the arm 105 can be reduced. Furthermore, it is preferable that the corners formed by the outer peripheral edge of the contact surface 104a and the electrode side surface 104b of each of the multiple electrodes 104 are curved or inclined surfaces. This eliminates the gap between the outer edge of the contact surface 104a of each of the multiple electrodes 104 and the lower end 102b1 of the multiple frame portions 102b, resulting in a shape where the outer edge of the contact surface 104a of each of the multiple electrodes 104 extends smoothly upward and radially outward from the base surface 102a, thereby reducing irritation to the surface of the arm 105.

[0053] The main body 102 has a plurality of receiving recesses 102e that separately accommodate the upper ends of a plurality of electrodes 104. Each of the receiving recesses 102e has a recess side surface 102e1 and a recess bottom surface 102e2. The recess side surface 102e1 of the receiving recess 102e faces the electrode side surface 104b of the electrode 104 to be housed in the receiving recess 102e and is formed by a frame portion 102b that surrounds the electrode 104. The recess bottom surface 102e2 of the receiving recess 102e holds the upper surface of the electrode 104 to be housed in the receiving recess 102e via an adhesive 109. The adhesive 109 is, for example, an adhesive or double-sided tape. The recess bottom surface 102e2 is located above the base bottom surface 102a. The recess bottom surface 102e2 may be located at the same height H as the base bottom surface 102a or below the base bottom surface 102a.

[0054] The main body 102 has a top surface 102f located on the opposite side of the base surface 102a, and a side surface 102g that connects the outer edge of the base surface 102a and the outer edge of the top surface 102f. The main body 102 has a substrate 110 inside the main body 102. The substrate 110 has a circuit that supplies voltage to a pair of application electrodes 107, and a circuit that detects the voltage or current applied to a pair of detection electrodes 108.

[0055] The measurement of bioelectrical impedance, which is biological information of a living organism, is performed by a control unit provided in the wearable device 101. The control unit may be located inside the main body 102 or outside the main body 102. If located inside the main body 102, the control unit may be located on the circuit board 110. The control unit can be composed of a computer having a processor and memory. The control unit may perform a process to calculate the amount of water content as higher-order biological information based on the measured bioelectrical impedance. The wearable device 101 may have a communication unit. The communication unit may be located on the circuit board 110. The control unit may transmit the calculated higher-order biological information, the amount of water content, to an external device such as the user's smartphone, a medical institution's server, or a cloud server via the communication unit. However, the control unit may transmit the measured bioelectrical impedance to the external device without performing the process of calculating the amount of water content as higher-order biological information from the measured bioelectrical impedance. In other words, the process of calculating the amount of water content as higher-order biological information based on the bioelectrical impedance measured by the control unit may be performed by an external device.

[0056] Furthermore, the control unit provided in the wearable device 101 may perform a process to calculate higher-order biological information such as heart rate, pulse rate, and blood pressure based on the pulse wave information measured by the pulse wave sensor 106. This allows for consideration of the decline in the user's cardiac function not only from the perspective of fluctuations in fluid content but also from the perspective of fluctuations in heart rate. The control unit may also transmit the calculated higher-order biological information, such as heart rate, pulse rate, and blood pressure, to an external device such as the user's smartphone, a medical institution's server, or a cloud server via the communication unit. However, the control unit may also transmit the measured pulse wave information itself to the external device without performing the process of calculating higher-order biological information from the pulse wave information measured by the pulse wave sensor 106. In other words, the process of calculating higher-order biological information based on the pulse wave information measured by the pulse wave sensor 106 may be performed by an external device.

[0057] The band 103 has one side portion 103a and the other side portion 103b. The one side portion 103a is connected to one end of the main body 102 in the longitudinal direction. The other side portion 103b is connected to the other end of the main body 102 in the longitudinal direction. The one side portion 103a and the other side portion 103b are wrapped around the arm 105 and detachably fixed to each other.

[0058] Next, a wearable device 201 according to a second embodiment of the present disclosure will be described. For example, the wearable device 201 according to the second embodiment of the present disclosure is attached to the surface of the arm of a living organism 202. The wearable device 201 has a main body having a base surface 203a1 facing the surface of the arm, a band body 204 connected to the main body and extending from the main body so as to define the longitudinal direction (lateral direction) of the wearable device 201, and positioned along the surface of the arm so as to be attached to the arm with its longitudinal direction aligned with the circumferential direction of the arm, and a plurality of electrodes (electrode portions 211) positioned within the base surface 203a1 in a bottom view and measuring biological information of the living organism 202 from the surface of the living organism 202. The plurality of electrodes have at least two electrodes positioned on either side of a longitudinal median line that passes through the center of the base surface 203a1 in the longitudinal direction and is perpendicular to the longitudinal direction in a bottom view. Each of the plurality of electrodes protrudes such that the contact surface with the surface of the arm is located below the base surface 203a1. The main body has a plurality of frame portions 212 that surround a plurality of electrodes and protrude downward from the base surface 203a1 when viewed from below, and a first groove portion (groove portion 213) that extends along the longitudinal midline. Each of the plurality of electrodes is surrounded by the plurality of frame portions 212 with a distance between them when viewed from below. The first groove portion has a groove bottom surface 213a formed by the base surface 203a1 and a pair of groove side surfaces 213b arranged on either side of the longitudinal midline (lateral midline O). The pair of groove side surfaces 213b of the first groove portion is formed by at least two of the plurality of frame portions 212 arranged on either side of the longitudinal midline. The wearable device 201 has a pulse wave sensor that is positioned in the first groove portion when viewed from below and measures pulse waves from the surface of the arm. The main body has a housing 203. The housing 203 has a bottom wall 203a facing the surface of the arm (the body surface of the target area of ​​the living organism 202). The band 204 is provided so as to extend from the housing 203 and is wrapped around the arm (the target area of ​​the living organism 202) for attachment. The pulse wave sensor is a photoelectric pulse wave sensor 205. The photoelectric pulse wave sensor 205 has a light-emitting part 205a, a light-receiving part 205b, and a window part 205c. The window part 205c is light-transmitting and forms part of the bottom wall 203a. The light-emitting part 205a and the light-receiving part 205b are each provided inside the housing 203. The bottom wall 203a has ribs 206 on both sides and extending parts 207 on both sides.The two-sided ribs 206 consist of a pair of ribs 206a. The pair of ribs 206a are provided on both sides of the window portion 205c in the longitudinal direction. Each of the pair of ribs 206a protrudes from the lower surface of the bottom wall 203a to below the two-sided extending portions 207, and extends in the short direction (vertical direction) perpendicular to the longitudinal direction when viewed from the bottom. In the short direction, the range in which each of the pair of ribs 206a extends includes the range in which the window portion 205c extends. The two-sided extending portions 207 consist of a pair of extending portions 207a. The pair of extending portions 207a are provided on both sides of the window portion 205c in the short direction. Each of the pair of extending portions 207a extends in the longitudinal direction. In the longitudinal direction, the range in which each of the pair of extending portions 207a extends includes the range in which the window portion 205c extends. The configuration of the wearable device 201 according to the second embodiment of this disclosure is not limited thereto.

[0059] If light from the external environment enters the photoplethysmography (PPS) sensor during measurement, it may cause noise in the measurement. Furthermore, if the light emitted by the PPS sensor leaks into the external environment during measurement, it may cause discomfort to the wearer and those around them, potentially affecting the external environment. From the perspective of improving measurement accuracy, it is desirable for the distance between the PPS sensor and the body surface to be short. Therefore, it is desirable to provide a wearable device that can suppress light from entering the PPS sensor from the external environment and prevent light emitted by the PPS sensor from leaking into the external environment during measurement, while also providing superior measurement accuracy.

[0060] As shown in Figure 9, the wearable device 201 according to the second embodiment of this disclosure is attached to the body surface of a target area of ​​a living organism 202. As shown in Figures 9 to 11, the wearable device 201 includes a housing 203 having a bottom wall 203a facing the body surface, a band 204 extending from the housing 203 and wrapped around the target area for attachment, and a photoelectric pulse wave sensor 205 for measuring pulse rate on the body surface. The photoelectric pulse wave sensor 205 has a light-emitting part 205a, a light-receiving part 205b, and a window part 205c. The window part 205c is light-transmitting and forms part of the bottom wall 203a. The light-emitting part 205a and the light-receiving part 205b are each provided inside the housing 203. The bottom wall 203a has ribs 206 on both sides and extending parts 207 on both sides. The ribs 206 on both sides consist of a pair of ribs 206a. A pair of ribs 206a are provided on both sides of the window portion 205c in the transverse direction, which is the direction in which the band body 204 extends. Each of the pair of ribs 206a protrudes from the lower surface of the bottom wall 203a to below the side extension portions 207, and extends in the longitudinal direction, which is perpendicular to the transverse direction. In the longitudinal direction, the range in which each of the pair of ribs 206a extends includes the range in which the window portion 205c extends. The side extension portions 207 consist of a pair of extension portions 207a. The pair of extension portions 207a are provided on both sides of the window portion 205c in the longitudinal direction. Each of the pair of extension portions 207a extends in the transverse direction. In the transverse direction, the range in which each of the pair of extension portions 207a extends includes the range in which the window portion 205c extends.

[0061] With the above configuration, light from the external environment entering the photoplethysmography sensor 205 from the side during measurement can be suppressed by the ribs 206 on both sides contacting the body surface and blocking the light, and light from entering from the vertical direction can be suppressed by the extensions 207 on both sides contacting the body surface and blocking the light. At this time, since the ribs 206 on both sides protrude from the lower surface of the bottom wall 203a to below the extensions 207 on both sides, the ribs 206 on both sides can easily contact the body surface which curves laterally. In addition, since the extensions 207 on both sides are recessed below the ribs 206 on both sides, the distance between the window portion 205c of the photoplethysmography sensor 205 and the body surface is reduced. Therefore, it is possible to suppress light from entering the photoplethysmography sensor 205 from the external environment during measurement, which can cause measurement noise, and to suppress light emitted by the photoplethysmography sensor 205 from leaking into the external environment and affecting the external environment, and to realize a wearable device 201 with excellent measurement accuracy.

[0062] The photoplethysmography (PPG) optical pulse wave sensor 205 is an optical pulse wave sensor that utilizes photoplethysmography to acquire pulse wave information (pulse wave signal) from the body surface. The light-emitting unit 205a emits light, and the reflected light from the body surface is received by the light-receiving unit 205b via the window unit 205c to measure the pulse wave information. The light-emitting unit 205a has multiple light-emitting units. The light-emitting unit 205a has a pair of infrared light-emitting units 205a1 and a pair of green light-emitting units 205a2 as its multiple light-emitting units. The light-emitting unit 205a can be made up of, for example, an LED (Light Emitting Diode). The light-receiving unit 205b can be made up of, for example, a photodiode. The light-emitting unit 205a, the light-receiving unit 205b and the light-shielding wall 205d are mounted on a substrate 208. The light-shielding wall 205d has a rectangular shape with four sides aligned in the vertical and horizontal directions when viewed from below, and is cylindrical with an opening at the bottom.

[0063] The light-receiving section 205b is located in the center of the base surface 203a1 when viewed from the bottom. The pair of infrared light emitting sections 205a1 are located on the horizontal median line O, flanking the light-receiving section 205b when viewed from the bottom. The pair of green light emitting sections 205a2 are located on the horizontal median line O, flanking the light-receiving section 205b when viewed from the bottom. The pair of infrared light emitting sections 205a1 are located further out than the pair of green light emitting sections 205a2 in the vertical direction. The window section 205c extends elongated along the horizontal median line O and has a rectangular shape with four sides aligned in the vertical and horizontal directions when viewed from the bottom.

[0064] The photoplethoracometer 205 has a light-shielding wall 205d. The light-shielding wall 205d is provided inside the housing 203 and surrounds the light-receiving unit 205b without surrounding the light-emitting unit 205a. With this configuration, the light emitted from the light-emitting unit 205a, reflected off the bottom wall 203a of the housing 203 at the outer edge of the window 205c and directed toward the light-receiving unit 205b is blocked by the light-shielding wall 205d, thereby suppressing the incidence of such light on the light-receiving unit 205b. Therefore, a wide irradiation range of the light emitted from the light-emitting unit 205a can be secured, making it easier to secure the amount of reflected light received from the body surface, and the reception of reflected light at the bottom wall 203a, which becomes measurement noise, can be suppressed, thereby improving measurement accuracy. From the viewpoint of enhancing this effect, it is preferable that the distance D along the vertical direction from the outer edge of the window portion 205c to the light-emitting portion 205a (the center Q of the light-emitting portion closest to the outer edge) in a cross section perpendicular to the horizontal direction is 1.0 to 4.5 mm.

[0065] The first distance D1 is defined as the distance along the vertical direction from the light-receiving section 205b to the lower surface of the window section 205c in a cross section perpendicular to the horizontal direction. The second distance D2 is defined as the distance along the vertical direction from the light-receiving section 205b to the outer edge of the window section 205c in a cross section perpendicular to the horizontal direction. The third distance D3 is defined as the distance along the vertical direction from the light-receiving section 205b to the lower surface of the light-shielding wall 205d in a cross section perpendicular to the horizontal direction. When the second distance D2 and the third distance D3 are fixed, a smaller first distance D1 makes it easier for the light-receiving section 205b to receive reflected light from the body surface, but it also makes it easier to receive light from the external environment, which becomes measurement noise. For this reason, it is preferable that the value obtained by dividing the second distance D2 by the first distance D1 is 8 times or more the third distance D3 and 12 times or less the third distance D3. However, the units of the first distance D1, second distance D2, and third distance D3 are mm. This configuration makes it easier to receive reflected light from the body surface and suppresses measurement noise, thereby improving measurement accuracy.

[0066] The wearable device 201 has a first electrode 209 and a second electrode 210 for measuring biological information of a living organism 2 from the body surface. The first electrode 209 is surrounded by one of a pair of ribs 206a. The second electrode 210 is surrounded by the other of the pair of ribs 206a. With this configuration, it is possible to measure biological information using multiple electrodes while obtaining the aforementioned effects of the ribs 206 on both sides.

[0067] The band 204 is provided so as to extend laterally from the housing 203 (in the longitudinal direction of the wearable device 1) and is wrapped around the arm (e.g., wrist) as the target area. The band 204 has one side portion 204a and the other side portion 204b. The one side portion 204a is connected to one end of the housing 203 in the later direction. The other side portion 204b is connected to the other end of the housing 203 in the later direction. The one side portion 204a and the other side portion 204b are wrapped around the target area and fixed to each other so as to be detachable.

[0068] The wearable device 201 measures bioelectrical impedance as biological information and enables the calculation of the amount of water in the arm based on the measured bioelectrical impedance. This makes it possible to detect edema in the body 202. For example, it is known that when cardiac function or renal function of the body 202 declines, edema occurs, in which fluid accumulates in or under the skin. With the wearable device 201, by calculating the amount of water in the arm of a user who has heart disease or kidney disease, a decline in cardiac function or renal function can be detected early. Also, it is known that when lymphatic fluid flow decreases in a patient due to breast cancer treatment, edema occurs, in which fluid accumulates in or under the skin of the treated upper limb. With the wearable device 201, by calculating the amount of water in the arm of a user who has breast cancer, breast cancer-related lymphedema can be detected early.

[0069] The wearable device 201 has an electrode section 211 having a first electrode 209 and a second electrode 210. The electrode section 211 is arranged on either side of a lateral intermediate line O that passes through the center of the base surface 203a1, which constitutes the bottom surface of the bottom wall 203a in the lateral direction when viewed from the bottom. The electrode section 211 has a pair of application electrodes 211a for applying a voltage to the body surface and a pair of detection electrodes 211b for detecting the voltage or current between the pair of application electrodes 211a. The first electrode 209 and the second electrode 210 are a pair of application electrodes 211a, but are not limited to this.

[0070] A pair of application electrodes 211a are arranged on either side of the lateral midline O of the base surface 203a1, and a pair of detection electrodes 211b are arranged on either side of the lateral midline O of the base surface 203a1.

[0071] One of the pair of application electrodes 211a is positioned with one of the pair of detection electrodes 211b, straddling a vertical intermediate line P that passes through the center of the base surface 203a1 in the vertical direction perpendicular to the horizontal direction when viewed from the bottom. The other of the pair of application electrodes 211a is positioned with the other of the pair of detection electrodes 211b, straddling the vertical intermediate line P of the base surface 203a1.

[0072] Bioelectrical impedance is measured by calculating it based on the voltage or current detected by a pair of detection electrodes 211b. To improve measurement accuracy, a pair of application electrodes 211a not only apply voltage but also detect voltage or current, and the bioelectrical impedance is measured based on the voltage or current detected by these four electrodes. Alternatively, the bioelectrical impedance may be simply calculated based only on the voltage or current detected by the pair of detection electrodes 211b.

[0073] The electrode section 211 may have only a pair of application electrodes 211a (first electrode 209 and second electrode 2010), and may be configured to not only apply voltage but also detect voltage or current using this pair of application electrodes 211a. In this case as well, bioelectrical impedance can be easily calculated.

[0074] The substrate 8 has a circuit that supplies voltage to a pair of application electrodes 211a and a circuit that detects the voltage or current applied to a pair of detection electrodes 211b.

[0075] The measurement of bioelectrical impedance is performed by the control unit. The control unit may be located inside or outside the housing 203. If located inside the housing 203, the control unit may be located on the circuit board 208. The control unit can be composed of a computer having a processor and memory. The control unit may perform a process to calculate the amount of water content as higher-order biological information based on the measured bioelectrical impedance. The wearable device 201 may have a communication unit. The communication unit may be located on the circuit board 208. The control unit may transmit the calculated higher-order biological information, the amount of water content, to an external device such as the user's smartphone, a medical institution's server, or a cloud server via the communication unit. However, the control unit may transmit the measured bioelectrical impedance to the external device without performing the process of calculating the amount of water content as higher-order biological information from the measured bioelectrical impedance. In other words, the process of calculating the amount of water content as higher-order biological information based on the bioelectrical impedance measured by the control unit may be performed by an external device.

[0076] The wearable device 201 has a pulse wave information processing unit that processes pulse wave information measured by the light receiving unit 205b of the photoelectric pulse wave sensor 205. The pulse wave information processing unit may be located inside the housing 203 or outside the housing 203. If located inside the housing 203, the pulse wave information processing unit may be located on the circuit board 208. The pulse wave information processing unit may perform processing to calculate higher-order biological information such as heart rate, pulse rate, and blood pressure based on the pulse wave information measured by the photoelectric pulse wave sensor 205. This allows for consideration of the wearer's decline in cardiac function not only from the perspective of fluctuations in fluid content but also from the perspective of fluctuations in heart rate. Furthermore, the pulse wave information processing unit may transmit the calculated higher-order biological information such as heart rate, pulse rate, and blood pressure to an external device such as the wearer's smartphone, a medical institution's server, or a cloud server via a communication unit. However, the pulse wave information processing unit may transmit the measured pulse wave information itself to an external device without performing processing to calculate higher-order biological information from the pulse wave information measured by the photoelectric pulse wave sensor 205. In other words, the process of calculating higher-order biological information based on the pulse wave information measured by the photoelectric pulse wave sensor 205 may be performed by an external device.

[0077] The ribs 206 on both sides have a plurality of frame portions 212 that surround a plurality of electrodes and protrude downward from the base surface 203a1 when viewed from below, and a groove portion 213 that extends along the lateral midline O. Each of the plurality of electrodes is surrounded by the plurality of frame portions 212 with a distance between them when viewed from below. As shown in Figure 9, the groove portion 213 has a groove bottom surface 213a formed by the base surface 203a1 and a pair of groove side surfaces 213b arranged on either side of the lateral midline O. The pair of groove side surfaces 213b of the groove portion 213 are formed by at least two of the plurality of frame portions 212 arranged on either side of the lateral midline O.

[0078] According to the above configuration, each of the multiple electrodes is surrounded by multiple frame portions 212, with spacing between them when viewed from below, and the contact surface with the surface of the arm protruding below the base surface 203a1. This allows for stable contact of the contact surface with the surface of the arm while suppressing contact of the electrode sides with the arm surface, which may be raised by the pressure of the multiple electrodes. Therefore, the contact area of ​​each of the multiple electrodes with the surface of the arm is suppressed from changing significantly depending on the degree of pressure applied to the contact surface with the arm surface, and the bioelectrical impedance, which is biological information of the living organism 202, can be measured stably. In addition, the multiple frame portions 212 also suppress displacement or detachment of the electrodes due to contact of external objects with the corners formed by the outer edge of the contact surface and the electrode side of each of the multiple electrodes.

[0079] The protrusion length L (see Figure 9) of each of the multiple frame portions 212 from the base surface 203a1 is the same as, or less than, the height H (see Figure 9) from the base surface 203a1 to the contact surface of the electrode surrounded by the frame portion 212 among the multiple electrodes. With the above configuration, when the multiple electrodes are pressed against the surface of the arm, the contact surfaces can be made to contact the surface of the arm more stably. Therefore, the bioelectrical impedance, which is biological information of the living body 2, can be measured more stably.

[0080] The configuration in which both side ribs 206 have multiple frame portions 212 makes it possible to suppress light from the external environment from entering the photoplethysmography sensor 205 during measurement, which can cause measurement noise, and to suppress light emitted by the photoplethysmography sensor 205 from leaking into the external environment and affecting the external environment. Furthermore, when multiple electrodes are pressed against the surface of the arm, the contact surfaces can be made to contact the surface of the arm more stably. As a result, a wearable device 201 can be realized that has excellent measurement accuracy for both pulse wave information from the photoplethysmography sensor 205 and bioelectrical impedance from multiple electrodes.

[0081] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified in various ways without departing from the gist of this disclosure.

[0082] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified in various ways without departing from the gist of this disclosure.

[0083] For example, in the first embodiment, the multiple electrodes 104 arranged on the base surface 102a of the main body 102 may be used not only to measure bioelectrical impedance as biological information of a living organism, but also to measure other biological information such as skin potential, electrocardiogram, or electromyogram. When measuring an electrocardiogram, in addition to the multiple electrodes 104 arranged on the base surface 102a of the main body 102, additional electrodes for measurement may be placed on the top surface 102f or side surface 102g of the main body 102.

[0084] Furthermore, in the second embodiment, the electrode portion 211, which is positioned on the base surface 203a1 of the housing 203, may be used not only to measure bioelectrical impedance as biological information of the living body 202, but also to measure other biological information such as skin potential, electrocardiogram, or electromyogram. When measuring an electrocardiogram, in addition to the electrode portion 211 provided on the base surface 203a1 of the housing 203, measuring electrodes may be provided on the top or side surface of the housing 203.

[0085] 101 Wearable device 102 Main body 102a Base surface 102b Frame portion 102b1 Lower end 102b2 Outer surface 102b3 First frame portion 102b4 Second frame portion 102c First groove portion 102c1 Groove bottom surface 102c2 Groove side surface 102d Second groove portion 102d1 Groove bottom surface 102d2 Groove side surface 102e Receiving recess 102e1 Recess side surface 102e2 Recess bottom surface 102f Top surface 102g Main body side surface 103 Band portion 103a One side portion 103b Other side portion 104 Electrode 104a Contact surface 104b Electrode side surface 105 Arm 106 Pulse wave sensor 107 Application electrode 108 Detection electrode 109 Adhesive 110 Substrate 201 Wearable device 202 Biological body 203 Housing 203a Bottom wall 203a1 Base surface 204 Band body 204a One side portion 204b Other side portion 205 Photoelectric pulse wave sensor 205a Light-emitting part 205a1 Infrared light irradiation part 205a2 Green light irradiation part 205b Light-receiving part 205c Window part 205d Light-shielding wall 206 Ribs on both sides 206a Ribs 207 Extended parts on both sides 207a Extended part 208 Substrate 209 First electrode 210 Second electrode 211 Electrode part 211a Electrode for application 211b Detection electrode 212 Frame part 213 Groove part 213a Groove bottom surface 213b Groove side surface D Distance D1 1st distance D2 2nd distance D3 3rd distance H Height L Projection length O Longitudinal midline (horizontal midline) P Shortitudinal midline (vertical midline) Q Center W Width

Claims

1. A wearable device to be attached to the surface of a living arm, comprising: a main body having a base surface facing the surface of the arm; a band connected to the main body, extending from the main body to define the longitudinal direction of the wearable device, and positioned along the surface of the arm such that the longitudinal direction is along the circumferential direction of the arm, thereby being attached to the arm; and a plurality of electrodes positioned within the base surface in a bottom view for measuring biological information of the living body from the surface of the living body, wherein the plurality of electrodes have at least two electrodes positioned on either side of a longitudinal midline passing through the center of the base surface in the longitudinal direction and perpendicular to the longitudinal direction in a bottom view, each of the plurality of electrodes protrudes such that the contact surface with the surface of the arm is located below the base surface, and the main body has a plurality of frame portions surrounding the plurality of electrodes in a bottom view and protruding downward from the base surface, and a first groove portion extending along the longitudinal midline. Each of the plurality of electrodes is surrounded by the plurality of frame portions at intervals from each other when viewed from the bottom, and the first groove portion has a groove bottom surface formed by the base surface and a pair of groove side surfaces arranged on either side of the longitudinal midline, and the pair of groove side surfaces of the first groove portion is formed by at least two of the plurality of frame portions arranged on either side of the longitudinal midline, in a wearable device.

2. The wearable device according to claim 1, wherein the projection length L of each of the plurality of frame portions from the base surface is equal to or less than the height H from the base surface to the contact surface of the electrode surrounded by the frame portion among the plurality of electrodes.

3. The wearable device according to claim 1, wherein the protruding length L of each of the plurality of frame portions from the base surface is 30 to 95% of the height H from the base surface to the contact surface of the electrode surrounded by the frame portion among the plurality of electrodes.

4. The wearable device according to claim 1, wherein the height H from the base surface to the contact surface of each of the plurality of electrodes is 0.5 to 1.5 mm.

5. The wearable device according to claim 1, wherein, in a view from the bottom, the width W of the frame portion in the direction from the outer peripheral edge of the contact surface of each of the surrounding plurality of electrodes toward the outer edge of the base surface is 0.5 to 1.5 mm.

6. The wearable device according to claim 1, wherein the plurality of electrodes have electrodes positioned with respect to at least two electrodes, straddling a midline in the short direction perpendicular to the short direction, passing through the center of the base surface in the short direction perpendicular to the longitudinal direction when viewed from the bottom, the main body has a second groove portion extending along the midline in the short direction, the second groove portion has a groove bottom surface formed by the base surface and a pair of groove side surfaces positioned straddling the midline in the short direction, and the pair of groove side surfaces of the second groove portion are formed by at least two frame portions of the frame portion positioned straddling the midline in the short direction.

7. The wearable device according to claim 1, further comprising a pulse wave sensor positioned in the first groove in a bottom view for measuring pulse waves from the surface of the arm.

8. The wearable device according to claim 1, wherein the plurality of electrodes comprises a pair of application electrodes for applying a voltage to the surface of the arm, and a pair of detection electrodes for detecting a voltage or current between the pair of application electrodes.

9. The wearable device according to claim 8, wherein the pair of application electrodes are arranged on either side of the longitudinal midline when viewed from the bottom, and the pair of detection electrodes are arranged on either side of the longitudinal midline when viewed from the bottom.

10. The wearable device according to claim 9, wherein one of the pair of application electrodes is positioned with respect to one of the pair of detection electrodes, with respect to a midline in the short direction passing through the center of the base surface in the short direction perpendicular to the longitudinal direction in a view from the bottom, and the other of the pair of application electrodes is positioned with respect to the midline in the short direction in a view from the bottom, with respect to the midline in the short direction.

11. The wearable device according to claim 10, wherein the plurality of frame portions have four frame portions that separately surround the pair of application electrodes and the pair of detection electrodes, the main body has a second groove portion extending along the midline in the short direction, the second groove portion has a groove bottom surface formed by the base surface and a pair of groove side surfaces arranged on either side of the midline in the short direction, and the pair of groove side surfaces of the first groove portion and the pair of groove side surfaces of the second groove portion are each formed by the four frame portions.

12. The wearable device according to claim 10, wherein the plurality of frame portions comprises: a first frame portion surrounding two electrodes of the plurality of electrodes arranged on one side of the longitudinal midline with respect to the short midline; and a second frame portion surrounding two electrodes of the plurality of electrodes arranged on the other side of the longitudinal midline with respect to the short midline, wherein the first frame portion extends along the short midline such that the two electrodes arranged on one side of the longitudinal midline with respect to the short midline are adjacent to each other via the first frame portion; and the second frame portion extends along the short midline such that the two electrodes arranged on the other side of the longitudinal midline with respect to the short midline are adjacent to each other via the second frame portion.

13. The wearable device according to claim 1, wherein the biological information of the living organism is bioelectrical impedance.

14. The main body has a housing, the housing has a bottom wall facing the surface of the arm, the band is provided to extend from the housing and is wrapped around the arm for attachment, the pulse wave sensor is a photoelectric pulse wave sensor, the photoelectric pulse wave sensor has a light-emitting part, a light-receiving part and a window part, the window part is light-transmitting and forms part of the bottom wall, the light-emitting part and the light-receiving part are each provided inside the housing, the bottom wall has ribs on both sides and extending parts on both sides, the ribs on both sides consist of a pair of ribs, the pair of ribs are provided on both sides of the window part in the longitudinal direction, each of the pair of ribs protrudes from the lower surface of the bottom wall to below the extending parts on both sides and extends in the short direction perpendicular to the longitudinal direction when viewed from the bottom, in the short direction, the range in which the pair of ribs extend each includes the range in which the window part extends, and the extending parts on both sides consist of a pair of extending parts. The wearable device according to claim 7, wherein the pair of extending portions are provided on both sides of the window portion in the short direction, each of the pair of extending portions extends in the longitudinal direction, and in the longitudinal direction, the range to which each of the pair of extending portions extends includes the range to which the window portion extends.

15. The wearable device according to claim 14, wherein the photoelectric pulse wave sensor has a light-shielding wall, and the light-shielding wall is provided inside the housing and surrounds the light-receiving unit without surrounding the light-emitting unit.

16. The wearable device according to claim 15, wherein, in a cross section perpendicular to the longitudinal direction, the distance along the short direction from the outer edge of the window portion to the light-emitting portion is 1.0 to 4.5 mm.

17. The wearable device according to claim 15, wherein the distance along the vertical direction from the light-receiving portion to the lower surface of the window portion in a cross section perpendicular to the longitudinal direction is defined as the first distance, the distance along the short direction from the light-receiving portion to the outer edge of the window portion in a cross section perpendicular to the longitudinal direction is defined as the second distance, and the distance along the vertical direction from the light-receiving portion to the lower surface of the light-shielding wall in a cross section perpendicular to the longitudinal direction is defined as the third distance, and when the units of the first distance, the second distance and the third distance are mm, the value obtained by dividing the second distance by the first distance is 8 times or more and 12 times or less of the third distance.

18. The wearable device according to claim 14, comprising a first electrode and a second electrode for measuring biological information of the living organism from the surface of the arm, wherein the first electrode is surrounded by one of the pair of ribs and the second electrode is surrounded by the other of the pair of ribs.

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