JP2017223548A - Measuring device and wearable apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy in measuring the temperature of a deep part of a measurement target body.SOLUTION: There is provided a measuring device in contact with a measurement target body for measuring the temperature and heat flow thereof, the measuring device comprising: a sensor part including a plurality of temperature sensors or a temperature sensor and a heat flow sensor; and a substrate including the sensor part therein, and having a shortest distance from the center of a contact surface with the measurement target body to an outer edge of 5 mm or more and a longest distance of 71 mm or less, and a thermal conductivity of 0.1 W/m K or more and 3.0 W/m K or less.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a measuring device for measuring the temperature and heat flow of a measurement object.

  A technique is known in which a temperature sensor is installed on the surface of a measurement object and the depth temperature of the measurement object is measured. For example, Patent Document 1 discloses a technique for measuring a heat flow using detection values of a plurality of temperature sensors and obtaining a deep temperature from a measurement result.

Japanese Patent Laying-Open No. 2015-64369

  However, the technique of Patent Document 1 assumes an ideal state in which the heat conduction equation is established, and assumes that the heat flow released from the heat source inside the measured object is stored also on the measured object surface. The deep temperature is calculated. Therefore, when the heat flow increases or decreases in the process of conducting heat from the heat source to the surface of the object to be measured and an error occurs in both, there is a problem that the measurement accuracy of the deep temperature is lowered.

  This invention is made | formed in view of such a situation, and it aims at improving the measurement precision of the deep part temperature of a to-be-measured body.

  A first invention for solving the above-described problem is a measuring device for measuring temperature and heat flow in contact with a measurement object, and a plurality of temperature sensors, or a sensor unit having a temperature sensor and a heat flow sensor; The shortest distance from the center of the contact surface to the object to be measured to the outer edge is 5 [mm] or more and the longest distance is 71 [mm] or less, and the thermal conductivity is 0. 1 [W / m · K] to 3.0 [W / m · K] base material.

  As will be described later, the contact surface of the substrate to the object to be measured has a shortest distance from the center to the outer edge of 5 [mm] or more and a longest distance of 71 [mm] or less and a thermal conductivity of 0. An error between the heat flow emitted from the heat source inside the measured object and the heat flow emitted from the measured object surface by setting the power to 1 [W / m · K] or more and 3.0 [W / m · K] or less. Can be suppressed. Therefore, according to 1st invention, the measurement precision of the deep temperature of a to-be-measured body can be improved.

  As a second invention, the base material may constitute the measuring device according to the first invention having a thermal conductivity of 0.5 [W / m · K] or more.

  According to the second invention, the thermal conductivity of the substrate can be set to 0.5 [W / m · K] to 3.0 [W / m · K].

  In addition, as a third invention, the base material has the rectangular contact surface having a length and width of 10 [mm] × 10 [mm] or more and 100 [mm] × 100 [mm] or less. Or you may comprise the measuring apparatus of 2nd invention.

  According to the third aspect of the invention, the contact surface of the base material can be formed in a rectangular shape having a vertical and horizontal length of 10 [mm] × 10 [mm] or more and 100 [mm] × 100 [mm] or less.

  As a fourth invention, the base material has a circular shape with a diameter of 10 [mm] or more and 100 [mm] or less, or a short axis length of 10 [mm] or more and a long axis length of 100. You may comprise the measuring apparatus of the 1st or 2nd invention which has the said elliptical contact surface of [mm] or less.

  According to the fourth invention, the contact surface of the base material has a circular shape with a diameter of 10 [mm] or more and 100 [mm] or less, or the length of the short axis is 10 [mm] or more and the length of the long axis The length may be an ellipse of 100 [mm] or less.

  Further, as a fifth invention, a wearable device including the measuring device according to any one of the first to fourth inventions may be configured.

  According to the fifth invention, it is possible to realize a wearable device that exhibits the same effects as any of the first to fourth inventions.

  According to a sixth aspect of the present invention, the object to be measured is a person, and the measurement apparatus is attached to any one of the limbs of the person so that the central portion of the contact surface is located above the artery. You may comprise the wearable apparatus of 5th invention provided with the mounting part.

  According to the sixth invention, the temperature of the artery flowing under the skin can be accurately measured in the human limb.

The figure which shows the state which mounted | wore the wearable apparatus with the user. The external view which looked at the wearable apparatus from the surface side. The external view which looked at the wearable apparatus from the back side. The schematic diagram explaining a heat flow measurement. The figure explaining the measurement error of the heat flow resulting from the heat conductivity of a base material. The other figure explaining the measurement error of the heat flow resulting from the heat conductivity of a base material. The figure explaining simulation conditions. Other figures explaining simulation conditions. The figure which shows the temperature change of the heat-transfer layer on predetermined | prescribed simulation conditions. The figure which shows the temperature change of the heat-transfer layer on other simulation conditions. The figure which shows the temperature change of the heat-transfer layer on other simulation conditions. The figure which shows the heat flow change of the heat transfer layer on the simulation conditions of FIG. The figure which shows the heat flow change of the heat transfer layer on the simulation conditions of FIG. The figure which shows the heat flow change of the heat transfer layer on the simulation conditions of FIG. The schematic diagram which shows the contact surface of the base material in a modification.

  Hereinafter, an embodiment for carrying out the present invention will be described. It should be noted that the present invention is not limited to the embodiments described below, and modes to which the present invention can be applied are not limited to the following embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals.

  FIG. 1 is a diagram illustrating a state in which the wearable device 1 according to the present embodiment is mounted on a user 100. 2 and 3 are external views showing an example of the overall configuration of the wearable device 1. FIG. 2 shows the front side (the surface that becomes the outside environment when worn on the user 100), and FIG. 3 shows the back side. (Surfaces that come into contact with the skin surface when worn by the user 100) are shown. The wearable device 1 according to the present embodiment is a wristwatch-type electronic device that fastens a band 13 as a mounting portion provided on a main body case (exterior frame) 11 with a buckle or the like. It is attached and fixed to the skin surface by wrapping around. It is not limited to the configuration worn on the wrist, and for example, it is wrapped around another part such as the neck, chest, waist, forehead, etc. in addition to any part of the limb of the user 100 such as the upper arm, ankle, or thigh. It is good also as a structure. Further, the configuration is not limited to the configuration in which the band is wound around the skin surface. For example, an adhesive sheet that is detachable from the skin surface is provided as a mounting portion at an appropriate position such as an edge on the back surface side of the measuring device 20 and is attached to the user 100 for mounting. But you can.

  The main body case 11 is an exterior frame body that holds the wearable device 1 with the end face of the measuring device 20 exposed on the front surface side and the back surface side of the wearable device 1. Specifically, the measuring device 20 is assembled to the main body case 11 so that one end surface of the base material 23 is exposed as the contact surface 231 on the back surface side and the other end surface is exposed on the front surface side. Although not shown in the figure, in addition to the measurement device 20, the main body case 11 includes a calculation device that performs calculation processing of the measurement result, a storage device that stores the measurement result, a measurement result with the external device, and the like. A communication device or the like for transmitting / receiving the data is arranged at an appropriate place.

The measuring device 20 includes a sensor unit 21 and a base material 23 that includes the sensor unit 21 therein. As will be described later, the base material 23 is made of a material having a thermal conductivity λ _D within a range (0.1 [W / m · K] to 3.0 [W / m · K]). The contact surface 231 is formed in a size within a specified range (for example, a rectangular shape in which the vertical and horizontal lengths of the contact surface 231 are 10 [mm] × 10 [mm] or more and 100 [mm] × 100 [mm] or less). These design conditions will be described later.

  The sensor unit 21 detects a temperature difference generated inside the sensor unit 21 due to heat transfer between the living body surface on which the wearable device 1 is worn (in this embodiment, the skin surface of the wrist of the user 100) and the external environment, Measure the heat flow generated on the skin surface. The sensor unit 21 measures the temperature of the skin surface (skin temperature) together with the heat flow. At the time of wearing, the wearable device 1 is positioned such that the central portion of the sensor portion 21 (the central portion of the contact surface 231) is located above the artery 101 (for example, radial artery) 101 that runs on the wrist.

[Overview]
FIG. 4 is a schematic diagram for explaining the heat flow measurement by the measuring device 20. One of the main heat sources in a living body such as a human body is an arterial blood vessel. In the case of the wrist, blood flowing through the radial artery or the like becomes a large heat source. And as shown by the arrow in FIG. 4, the heat | fever is discharge | released radially from the artery 101 which is a heat source. Here, the measuring apparatus 20 measures the heat flow as a heat flow released from the human body by bringing the base material 23 into contact with the skin surface to release heat to the external environment via the base material 23. Therefore, if the measuring device 20 is installed above the artery (radial artery in the present embodiment) 101, the heat flow accompanying the release of heat from the artery 101 is measured, and the skin temperature of the installed skin surface is also measured. be able to.

  For example, the sensor units 21 are opposed to each other in the thickness direction at the center portion of the base material 23 (the center portion of the contact surface 231) (or so that the positions in the thickness direction are different but overlap each other in plan view). It has two temperature sensors 211 and 213 arranged, and the heat flux (heat flow per unit area) at the skin surface position P11 immediately below is determined from the temperature difference (upper and lower temperature difference) detected by each temperature sensor 211 and 213. taking measurement. Further, the temperature detected by the temperature sensor 211 on the skin surface side when worn is measured as the skin temperature. The configuration of the sensor unit 21 is not limited to the configuration using two temperature sensors, and may be configured by a heat flow sensor that measures heat flow and a temperature sensor that measures skin temperature.

If the heat flow and skin temperature of the skin surface are obtained in this way, the subcutaneous deep temperature, for example, the temperature of the artery 101 as the heat source (hereinafter referred to as “heat source temperature”) can be measured (calculated). Heat source temperature _{T C} is expressed by the following equation (1). In the formula (1), R is the thermal resistance, Q is each represent heat flow, _{T S} is the skin temperature. The thermal resistance R can be obtained using the thermal conductivity of the layer between the skin surface position P11 and the blood vessel position P13 immediately below (the layer to which heat released from the artery 101 is transmitted). Hereinafter, the biological tissue layer is referred to as a “heat transfer layer”. Further, the heat flow Q can be obtained as a value proportional to the upper and lower temperature difference detected by the sensor unit 21.
T _C = R · Q + T _S (1)

By the way, calculation of the heat source temperature by Formula (1) presupposes that a heat conduction equation is materialized. That is, the distance from an arbitrary outer surface of the measured object to the heat source is constant and the heat flow is generated isotropically and uniformly from the heat source, or the heat source exists at the center of the measured object and the heat source It is based on the principle based on the premise that the generated heat flow is preserved on the surface of the measured object by heat conduction in an ideal state where the heat flow is generated isotropically and uniformly. As the heat conduction equation, for example, a heat source can be compared with a cylindrical shape called a blood vessel, and a two-dimensional heat conduction equation assuming a cylindrical heat source can be used. However, the position (depth) of the wrist artery (for example, radial artery) 101 is not near the wrist cross-sectional center but is located near the epidermis on the palm side of the wrist and is offset from the cross-sectional center. This can affect the measurement accuracy of the heat flow.
Moreover, it is not only the problem on the measured object side. There are factors that can cause errors in heat flow measurement, such as the design conditions of the measuring device.

First, the thermal conductivity λ _D of the base material 23 is mentioned. 5 and 6 are diagrams for explaining the measurement error of the heat flow caused by the thermal conductivity λ _D of the base material 23. FIG. In FIG. 5, the heat conduction in the living body using the artery 101 as a heat source is schematically shown in the case where the heat conductivity λ _S of the skin layer 103 is larger than the heat conductivity λ _D of the base material 23 (λ _D <λ _S ). FIG. 6 shows the opposite case (λ _D > λ _S ). The skin layer 103 exists on the epidermis side in the body to be measured in the heat transfer layer, and is necessarily present between the artery 101 and the measuring device 20. 5 and 6 show heat transfer paths focusing only on heat flow vertically upward from the artery 101 (in the normal direction of the arterial blood vessel at the blood vessel position P13). As shown in FIG. 5, in the case of λ _D <λ _S , since it is difficult to transfer heat across the skin surface to the base material 23 side, a part of the heat escapes to the side, and the skin surface measured as a result The heat flow at the position P11 decreases compared to the heat flow from the artery 101 (heat flow at the blood vessel position P13). On the other hand, in the case of λ _D > λ _S shown in FIG. 6, heat is easily transferred to the base material 23 side, and thus a phenomenon occurs in which the measured heat flow increases, contrary to the case of FIG. 5.

  Secondly, the size of the base material 23 is mentioned. Considering only the size of the base material 23, it can be said that the measurement accuracy of the heat flow is improved as the contact surface 231 is wider. This is because if the entire area of the object to be measured is covered with the base material, all the heat released from the heat source is released to the outside environment through the base material.

Thirdly, the thermal conductivity λ _S of the skin layer 103 is mentioned. The thermal conductivity of the living tissue itself forming the heat transfer layer is fixed at a specific value. However, since the capillaries have developed in the skin layer 103, the thermal conductivity λ _S apparently varies depending on the blood flow state of the capillaries. Specifically, the thermal conductivity λ _S of the skin layer 103 when the blood flow state is bad is about 0.5 [W / m · K], which is the thermal conductivity of the skin, whereas the blood flow state When it is good, it rises to about 3.0 [W / m · K]. Therefore, the blood flow state of the capillaries in the skin layer 103 causes an increase or decrease in the measured heat flow.

Therefore, a model to be measured (wrist model) assuming the wrist was defined, and a plurality of temperature distributions in the heat transfer layer were verified by simulation. The simulation shows that the heat conductivity λ _S of the skin layer 103 is 3.0 (the apparent upper limit value) when the blood flow state is good under the condition that the heat conductivity λ _D and the size of the base material 23 are different. In the case of [W / m · K], the thermal conductivity λ _S of the skin layer 103 is 0.5 [W / m · K] when the blood flow state is bad (which is an apparent lower limit value). In each case.

  7 and 8 are diagrams for explaining simulation conditions. FIG. 7 shows a schematic perspective view of the wrist model M100 on which the base material M23 is installed, and FIG. 8 schematically shows a cross section of the wrist model M100 including the installation position of the base material M23. The wrist model M100 was set as a cylindrical body having a radius of 25 [mm]. Further, a cylindrical body having a radius of 2.3 [mm] assuming the artery (radial artery) 101 was set as the heat source M101 so that the depth position thereof was 5 [mm].

The thermal conductivity λ _D of the base material M23 is approximately 0.0241 [W / m · K], 0.1 [W / m · K], which is similar to that of air, and the apparent thermal conductivity λ of the skin layer 103. 0.5 [W / m · K] which is the lower limit of _S , 3.0 [W / m · K] which is the apparent upper limit, 10.0 [W / m] which is similar to stainless steel and the like -It was set stepwise within a range of 0.0241 [W / m · K] including each value of K] to 10.0 [W / m · K].

  The base material M23 was set so that the center of the contact surface M231 was positioned above the heat source M101. And the magnitude | size of the base material M23 is defined by angle range (theta) centering on the direction which goes to the center of the contact surface M231 which opposes from the heat source M101 in the cross section (FIG. 8) of the wrist model M100, 60 [degree], It was set in three stages of 120 [°] and 180 [°]. Specifically, the contact surface M231 of the base material M23 in the case of θ = 60 [°] is a rectangular shape having a vertical and horizontal length of 5 [mm] × 5 [mm], and θ = 120 [°]. In this case, the contact surface M231 of the base material M23 has a rectangular shape with a vertical and horizontal length of 10 [mm] × 10 [mm], and the contact surface M231 of the base material M23 in the case of θ = 180 [°] The length was 16 [mm] × 16 [mm] in a rectangular shape.

9 to 11 are graphs showing the temperature change of the heat transfer layer obtained as a result of the simulation with the horizontal axis as the thermal resistance R. FIG. FIG. 9 shows the simulation results of θ = 60 [°], FIG. 10 shows the simulation results of θ = 120 [°], and FIG. 11 shows the simulation results of θ = 180 [°]. In each figure, a group of lower sides surrounded by a one-dot chain line corresponds to a temperature change when the thermal conductivity λ _S of the skin layer 103 is 0.5 [W / m · K], and each graph However, the thermal conductivity λ _D of the base material M23 is 0.0241 [W / m · K], 0.5 [W / m · K], 3.0 [W / M · K] and 10.0 [W / m · K], corresponding to temperature changes. Further, in each figure, a group on the upper side partially surrounded by a two-dot chain line corresponds to a temperature change when the thermal conductivity λ _S of the skin layer 103 is set to 3.0 [W / m · K]. . The thermal conductivity λ _D of the base material M23 according to each graph is as shown in the attached numerical values. 9 to 11, illustration of simulation results when the thermal conductivity λ _D of the base material M23 is 0.1 [W / m · K] is omitted.

12 to 14 are graphs showing the heat flow change of the heat transfer layer obtained from the simulation results of FIGS. 9 to 11 with the horizontal axis as the thermal resistance R. FIG. FIG. 12 corresponds to the simulation result of θ = 60 [°], FIG. 13 corresponds to the simulation result of θ = 120 [°], and FIG. 14 corresponds to the simulation result of θ = 180 [°]. In each figure, a group of the upper side partly surrounded by an alternate long and short dash line corresponds to a temperature change when the thermal conductivity λ _S of the skin layer 103 is set to 0.5 [W / m · K], and each graph However, as indicated by numerical values, the thermal conductivity λ _D of the base material M23 is 10.0 [W / m · K], 3.0 [W / m · K], 0.5 [W] from above. / M · K], 0.1 [W / m · K], and 0.0241 [W / m · K], corresponding to temperature changes. In each figure, a group on the lower side surrounded by a two-dot chain line corresponds to a temperature change when the thermal conductivity λ _S of the skin layer 103 is 3.0 [W / m · K]. . The thermal conductivity λ _D of the base material M23 according to each graph is as shown in the attached numerical values.

  Here, the thermal resistance R on the horizontal axis is the thermal resistance value at each position in the depth direction of the heat transfer layer, and can be considered in place of the depth. The value of the thermal resistance R at the heat source position is “0”, and the value P2 at the right end of the graph corresponds to the skin surface position (on the simulation, the surface position of the wrist model M100 with which the contact surface M231 contacts). In each figure, the range of the thermal resistance R surrounded by the alternate long and short dash line corresponds to the region of the skin layer 103.

  First, in the case of θ = 60 [°], as shown in FIG. 9, there was no significant difference in the temperature change of the heat transfer layer under each condition. And as shown in FIG. 12, the heat flow change of a heat transfer layer shows the decreasing tendency as a whole under any conditions, and it turns out that the heat flow of a heat source position is not preserve | saved in the skin surface position.

On the other hand, as shown in FIGS. 10 and 11, in the case of θ = 120 [°] and θ = 180 [°], the temperature change of the heat transfer layer varies depending on the thermal conductivity λ _D of the base material M23. As a result. Further, when paying attention to each graph, the inclination is not constant, and is gentle or steep in the region of the skin layer 103. For example, in the case of θ = 120 [°] in FIG. 10, the thermal conductivity λ _S of the skin layer 103 is 0.5 [W / m · K] and the thermal conductivity λ _{D of the} base material M23 is 0.0241 [ W / m · K], the slope of the corresponding graph G211 is smaller in the region of the skin layer 103 than in the deeper region. Looking at the corresponding change in heat flow in FIG. 13, the graph G213 shows a downward trend in the region of the skin layer 103, and the heat flow is decreasing. On the other hand, in FIG. 10, when the thermal conductivity λ _S of the skin layer 103 is 0.5 [W / m · K] and the thermal conductivity λ _{D of the} base material M23 is 10.0 [W / m · K]. When paying attention, the slope of the graph G231 is larger in the region of the skin layer 103 than in the deeper region. Looking at the corresponding heat flow change in FIG. 13, the graph G233 shows an upward trend in the region of the skin layer 103, and the heat flow is increased.

As described above, the measurement accuracy of the heat source temperature using the equation (1) is affected by an error (heat flow measurement error) between the heat flow at the heat source position and the heat flow at the skin surface position. If they match, the heat source temperature can be measured accurately. Therefore, the condition where the slope of the heat flow change graph is horizontal is considered as the optimum condition. Therefore, according to the simulation result, when θ = 120 [°] or more, the thermal conductivity λ _S of the skin layer 103 is 0.5 [W / m · K], that is, the blood flow of the skin layer 103. When the state is poor, the thermal conductivity λ _D of the base material M23 is the optimum condition between 0.5 [W / m · K] and 3.0 [W / m · K].

Here, when the thermal conductivity λ _S of the skin layer 103 is 3.0 [W / m · K], that is, when the blood flow state of the skin layer 103 is good, θ = 120 [°] or more may be used. The heat flow change shows an overall decreasing trend. However, it is known that the heat source temperature T _C when the blood flow state is good is substantially equal to the skin temperature T _S, and the heat source temperature T _C can be obtained without using Equation (1). That is, if the thermal conductivity λ _D and the size of the base material M23 are defined using the optimum conditions based on the simulation result in which the thermal conductivity λ _S of the skin layer 103 is 0.5 [W / m · K], Regardless of the blood flow state of the skin layer 103, the heat source temperature can be accurately measured.

Specifically, from the above simulation results, considering the allowable measurement error range of the heat source temperature, the thermal conductivity λ _D of the base material 23 is 0.1 [W / m · K] or more and 3.0 [ W / m · K] or less. It is more preferable that the skin layer 103 has an apparent thermal conductivity λ _{S in} the range of 0.5 [W / m · K] to 3.0 [W / m · K].

  Next, as for the size of the base material 23, the shortest distance from the center of the contact surface 231 to the outer edge is preferably 5 [mm] or more and the longest distance is 71 [mm] or less. The longest distance 71 [mm] is the distance (50 × √2) from the center of the 100 [mm] square to the vertex. For example, when the contact surface 231 has a rectangular shape, the vertical and horizontal lengths may be 10 [mm] × 10 [mm] or more and 100 [mm] × 100 [mm] or less.

  Note that the shape of the contact surface of the substrate is not limited to the rectangular shape, and may be any shape as long as it is within the above prescribed range. For example, the shape of the contact surface may be a circle having a diameter of 10 [mm] or more and 100 [mm] or less. Alternatively, as shown in FIG. 15, the shape of the contact surface 231a may be an ellipse having a short axis length L31 of 10 [mm] or more and a long axis length L33 of 100 [mm] or less.

  Moreover, although it does not limit about the thickness of the base material 23, thickness reduction of the measuring apparatus 20 can be achieved by employ | adopting a thin temperature sensor and a heat flow sensor, and comprising the sensor part 21. FIG.

As described above, by using the base material 23 having the thermal conductivity λ _D and the size satisfying the above-mentioned definition, the error between the heat flow at the heat source position and the heat flow at the skin surface position can be sufficiently suppressed. According to this, the measurement accuracy of the heat source temperature can be improved.

  In the above-described embodiment, the human body is exemplified as the body to be measured. However, the present invention can be similarly applied to the case where the heat source temperature is measured for a body to be measured in which a linear or cylindrical heat source exists. In addition, the temperature of the blood vessel position (heat source temperature) is not limited to the measurement, and the depth temperature at an arbitrary depth position of the heat transfer layer may be measured.

  In the above embodiment, the radial artery is exemplified as the heat source. However, the present invention can be similarly applied to the case where the heat source temperature is measured for another artery. For example, ulnar artery, brachial artery, femoral artery, etc., carotid artery, subclavian artery, aorta, etc. may be targeted. The heat source temperature can be measured by mounting so that the central portion of the contact surface 231 of the base material 23 is located above the artery. Here, “located above the artery” means that it is located above the skin surface position where the artery is running immediately below, and is located above the skin surface position closest to the artery. In other words,

  Wearable device ... 1, body case ... 11, band ... 13, measuring device ... 20, sensor unit ... 21, temperature sensor ... 211,213, base material ... 23, contact surface ... 231, user ... 100, artery ... 101, skin Layer ... 103

Claims (6)

A measuring device for measuring temperature and heat flow in contact with a measured object,
A plurality of temperature sensors, or a sensor unit having a temperature sensor and a heat flow sensor;
The sensor section is included inside, the shortest distance from the center of the contact surface to the object to be measured to the outer edge is 5 [mm] or more and the longest distance is 71 [mm] or less, and the thermal conductivity is 0.1. [W / m · K] to 3.0 [W / m · K] base material;
Measuring device. The base material has a thermal conductivity of 0.5 [W / m · K] or more.
The measuring apparatus according to claim 1. The base material has the rectangular contact surface whose length and width are 10 [mm] × 10 [mm] or more and 100 [mm] × 100 [mm] or less,
The measuring apparatus according to claim 1 or 2. The substrate has a circular shape with a diameter of 10 [mm] or more and 100 [mm] or less, or an elliptical shape with a short axis length of 10 [mm] or more and a long axis length of 100 [mm] or less. Having the contact surface,
The measuring apparatus according to claim 1 or 2.   A wearable device comprising the measurement device according to claim 1. The measured object is a person,
An attachment part for attaching the measurement device to any one of the extremities of the person so that the center part of the contact surface is located above the artery,
The wearable device according to claim 5, comprising: