JP5971394B2 - Temperature measurement system and temperature calculation method - Google Patents

Description

  The present invention relates to a temperature measurement system that measures the internal temperature of a measurement object.

  From body temperature, which is basic vital information, biological information such as health status, basic metabolic status, and mental status can be obtained. In order to determine the health, basal metabolic state, or mental state of a person or animal based on the body temperature of the human body or animal, information on the internal temperature (depth temperature) is used instead of the surface temperature of the human body or animal. is necessary.

  Also, for example, when measuring the internal temperature of a furnace, piping, etc., if a temperature measuring device can be provided outside the furnace or piping to measure the internal temperature, the temperature measuring device is provided inside the furnace, piping, etc. This eliminates the need for facilities and components, and makes it possible to use a temperature measuring device that is less expensive in terms of heat resistance, corrosion resistance, and measurement range, and also reduces construction costs.

  As a technique relating to the measurement of the internal temperature, for example, Patent Document 1 and Patent Document 2 that measure the temperature of a human body are known.

JP-A-55-29794 JP 2006-308538 A

  The technique disclosed in Patent Document 1 is a technique related to internal temperature measurement using a so-called heat flow compensation formula. This technique is a technique for measuring the internal temperature of a body to be measured by attaching a heat flow compensation type probe to the body surface and apparently radiating heat from the body surface to zero. In this case, the heater needs to be controlled in order to bring the living body and the probe into a temperature equilibrium state. Therefore, in addition to requiring electric power for operating the heater, precise temperature control of the heater is necessary in order to improve the measurement accuracy of the internal temperature.

  In addition, the technique disclosed in Patent Document 2 has a problem that the heat balance generated between the temperature measuring device and the surrounding environment (external environment) is not taken into account when calculating the internal temperature. That is, the technique of Patent Document 2 is a technique that presupposes that an ideal system can be formed, in which no heat balance is generated with the surrounding environment. However, in reality, since there is a heat balance between the temperature measuring device and the surrounding environment, there is a problem that the temperature measurement error due to this heat balance cannot be ignored.

  The present invention has been made in view of the above problems, and an object of the present invention is to propose a new technique for measuring the internal temperature of a measurement object.

  A first form for solving the above-described problem is that a contact having a plurality of temperature sensors at different positions and having thermal conductivity, an internal temperature of a measured object separately measured, and the contact A determination unit for determining a relative relationship of heat balance characteristics at the positions of the plurality of temperature sensors using detected temperatures of the plurality of temperature sensors when a child is brought into contact with the measurement object; and the heat balance characteristics And a temperature calculation unit that continuously calculates the internal temperature of the object to be measured using the relative relationships of the above and the detected temperatures of the plurality of temperature sensors.

  Further, as another form, there is a temperature calculation method for calculating an internal temperature of a measurement object using a contact having a plurality of temperature sensors at different positions and having thermal conductivity, which is separately measured. Using the internal temperature of the object to be measured and the detected temperatures of the plurality of temperature sensors when the contact is brought into contact with the object to be measured, the relative relationship of the heat balance characteristics at the positions of the plurality of temperature sensors And continuously calculating the internal temperature of the object to be measured using the relative relationship between the heat balance characteristics and the detected temperatures of the plurality of temperature sensors. It may be configured.

  According to the first embodiment and the like, the internal temperature of the object to be measured separately and a plurality of temperature sensors at different positions and a contact having thermal conductivity are brought into contact with the object to be measured. The relative temperatures of the heat balance characteristics at the positions of the plurality of temperature sensors are determined using the detected temperatures of the plurality of temperature sensors. Here, the heat balance means heat input / output, and the heat balance characteristic means the heat input / output characteristic.

  As will be described in detail in an embodiment described later, if the relative relationship of the heat balance characteristics at the positions of the plurality of temperature sensors is known, the internal temperature of the measurement object can be calculated using the detected temperatures of the plurality of temperature sensors. In this method, the temperature is detected by multiple temperature sensors while the contact is in contact with the object to be measured, and the heat balance characteristics determined from those detected temperatures and the internal temperature of the object to be measured that has been measured separately. The internal temperature of the object to be measured can be calculated simply by using the relative relationship. In this case, the internal temperature of the measured object can be correctly calculated by measuring the internal temperature of the measured object with high accuracy. Further, since the internal temperature is calculated in consideration of the heat balance characteristics at the positions of the plurality of temperature sensors, the temperature measurement error due to the heat balance can also be compensated.

  Further, as a second mode, in the temperature measurement system according to the first mode, the plurality of temperature sensors are provided at positions in the contact that have different heat balance characteristics from the outside of the contact. A measurement system may be configured.

  According to this 2nd form, the several temperature sensor is provided in the position in which the heat balance characteristic with the outside of a contactor differs in a contactor. By providing a plurality of temperature sensors at positions in the contact where the heat input / output characteristics differ from the outside of the contact, the heat balance characteristics at the positions of the plurality of temperature sensors can be made different.

  Further, as a third form, in the temperature measurement system of the first or second form, the contact is (1) a position where heat conduction characteristics from the contact surface contacting the measurement object to the position are different, (2) A temperature measurement system comprising a temperature sensor at a position where the heat conduction characteristics from the side surface other than the contact surface to the position differ, or (1) and (2) may be configured. Good.

  According to this 3rd form, a contactor is (1) the position where the heat conduction characteristics from the contact surface which contacts a to-be-measured body to the said position differ, (2) the heat from the side surfaces other than a contact surface to the said position Since the temperature sensor is provided at a position where the conduction characteristics are different, it is possible to cause a difference in the detected temperatures of the plurality of temperature sensors. In this case, it is good also as a structure which has a temperature sensor in the position of (1) and (2).

  Further, as a fourth form, in the temperature measurement system of any one of the first to third forms, the contactor has a plurality of layers having different heat conduction characteristics, and has a temperature sensor in the different layer. It is good also as comprising a temperature measurement system.

  According to this 4th form, by installing a temperature sensor in the several layer from which the thermal conductivity characteristic of a contactor differs, the heat balance characteristic in the position of several temperature sensor can be varied.

  Further, as a fifth aspect, in the temperature measurement system according to any one of the first to fourth aspects, the determination unit is configured to detect the detected temperatures of the plurality of temperature sensors with respect to the internal temperature of the measured object separately measured. It is good also as comprising the temperature measurement system which determines the relative relationship of the said heat balance characteristic using a difference.

  As will be described in detail in an embodiment described later, the internal temperature can be calculated according to a predetermined arithmetic expression based on the detected temperatures of the plurality of temperature sensors and the relative relationship of the heat balance characteristics. Further, by utilizing the internal temperature of the measured object measured separately, the relative relationship of the heat balance characteristics can be obtained reversibly from the calculation formula. At this time, the relative relationship of the heat balance characteristics can be obtained by using the difference in the detected temperatures of the plurality of temperature sensors with respect to the internal temperature of the measured object measured separately.

  Further, as a sixth mode, in the temperature measurement system according to any one of the first to fifth modes, the contact has three or more temperature sensors at different positions, and the temperature sensor provided in the contact Further comprising a selection unit that selects at least two temperature sensors from the above, the determination unit determines a relative relationship of heat balance characteristics at the position of the temperature sensor selected by the selection unit, the temperature calculation unit, A temperature measurement system that calculates the internal temperature of the measurement object using the relative relationship of the heat balance characteristics and the temperature detected by the temperature sensor selected by the selection unit may be configured.

  According to the sixth embodiment, at least two temperature sensors are selected from temperature sensors arranged at three or more different positions provided on the contact. Then, the relative relationship of the heat balance characteristics at the position of the selected temperature sensor is determined, and the internal temperature of the measured object is calculated using the relative relationship of the heat balance characteristics and the detected temperature of the selected temperature sensor. With this configuration, it is possible to calculate the internal temperature by selecting a temperature sensor suitable for calculating the internal temperature from among the temperature sensors arranged at three or more different positions.

  Further, as a seventh aspect, in the temperature measurement system according to any one of the first to sixth aspects, the body to be measured is a human body, and the contact is a head part, a neck part, or a body part indicating a deep body temperature. Contacted with the surface of a part that changes in temperature relative to any part, the determination unit is separately measured at a position to be measured inside any part of the head, neck, and torso showing the deep body temperature. A temperature and a detected temperature of the plurality of temperature sensors to determine a relative relationship between the heat balance characteristics, and the temperature calculation unit is configured to determine the relative relationship between the heat balance characteristics and the detected temperatures of the plurality of temperature sensors. And a temperature measurement system that continuously calculates the temperature of the measurement target position may be configured.

  According to the seventh embodiment, the body to be measured is a human body, and the contact is brought into contact with the surface of the part that changes in temperature relative to any part of the head, neck, and torso showing the deep body temperature. The Then, using the temperature separately measured at the measurement target position inside any part of the head, neck and torso showing the deep body temperature, and the detected temperature of the plurality of temperature sensors, the relative relationship of the heat balance characteristics is obtained. judge. Then, the temperature at the measurement target position is continuously calculated using the relative relationship of the heat balance characteristics and the detected temperatures of the plurality of temperature sensors. Thereby, among the human body, the temperature can be continuously calculated with any part of the head, neck and torso showing the deep body temperature as the measurement target position.

(1) The block diagram of a contactor. (2) Explanatory drawing of a heat flow path model. (3) Explanatory drawing of a heat flow path model. (1) An example of the installation position of the temperature sensor. (2) An example of the installation position of the temperature sensor. (3) An example of the installation position of the temperature sensor. (4) An example of the installation position of the temperature sensor. (1) One structural example of a contactor. (2) One structural example of a contactor. (3) One structural example of a contactor. (4) One configuration example of the contact. (1) One structural example of a contactor. (2) One structural example of a contactor. Explanatory drawing of an experimental result. The block diagram which shows the function structure of a temperature measurement system. The flowchart which shows the flow of a 1st main process. (1) The block diagram of the contact in a modification. (2) The functional block diagram of the process part in a modification. The flowchart which shows the flow of a 2nd main process. The flowchart which shows the flow of a 3rd main process.

1. Principle 1-1. Principle of Temperature Calculation FIG. 1 (FIGS. 1 (1) to 1 (3)) is an explanatory diagram of the principle of temperature calculation in the present embodiment. In the present embodiment, as shown in FIG. 1A, a contact 100 having a predetermined shape is brought into contact with the measurement object so that the contact surface ST is in contact with the measurement object to be measured for temperature.

  The contact 100 has thermal conductivity and is configured to have a plurality of temperature sensors at different positions in the contact 100. The contact 100 is made of a material having a predetermined thermal conductivity (or thermal resistance). One suitable material is silicone rubber.

  In the present embodiment, temperature sensors are provided at two different positions in the contact 100. Hereinafter, the two temperature sensors will be described as a first temperature sensor 11 and a second temperature sensor 12. Further, the positions at which the first temperature sensor 11 and the second temperature sensor 12 detect the temperature are illustrated and described as the first detection position P1 and the second detection position P2, respectively.

  A known sensor can be used as the temperature sensor. For example, a chip thermistor, a flexible substrate on which a thermistor pattern is printed, a sensor using a platinum resistance thermometer, a sensor using a thermocouple element, a PN junction element, a diode, or the like can be used. From the temperature sensor, an electrical signal corresponding to the temperature at the detection position (hereinafter referred to as “temperature detection signal”) is output, and the detected temperature of each temperature sensor is acquired based on the temperature detection signal.

  The position of the object to be measured for temperature measurement is hereinafter referred to as “measurement target position”. Further, an arbitrary position in the outside world is hereinafter referred to as an “outside world arbitrary position”. In this embodiment, the body to be measured is a human body, but it may be an organic object such as an animal other than the human body, or may be an inorganic object such as a furnace, piping, or engine. Further, the outside world means a measurement environment where a measurement object is placed.

Assume that the internal temperature of the object to be measured is higher than the external temperature. The heat moves from the higher temperature to the lower temperature. Therefore, here, a heat flow path with the measurement target position _Pc as the heat source and the external arbitrary position _Pout as the heat return point is considered. More specifically, a heat flow path (hereinafter referred to as “first heat flow path”) from the measurement target position P _c through the first detection position P1 to the external arbitrary position P _out and the measurement target position P _c. Consider two heat flow paths: a heat flow path (hereinafter referred to as a “second heat flow path”) that passes through the second detection position P2 and reaches the external arbitrary position _Pout .

  When a heat flow flows through the first and second heat flow paths, the process is affected by the inflow of heat from the outside and the outflow of heat to the outside. In the present embodiment, this heat exchange is called “heat balance”. If the above heat flow path is modeled in an electric circuit in consideration of this heat balance, a heat flow path model as shown in FIG. 1 (2) can be constructed.

In the heat flow path model of FIG. 1 (2), various paths are conceivable from the measurement target position _Pc to the first detection position P1, and various paths from the first detection position P1 to the external arbitrary position _Pout are also various. Possible routes. In the heat flow path model of FIG. 1 (2), each path is represented as a resistance. The same applies to the second heat flow path. Of course, the value of each thermal resistance is unknown.

When the heat flow path model of FIG. 1 (2) is simplified, it becomes as shown in FIG. 1 (3). A thermal resistance obtained by synthesizing thermal resistances connected in parallel between the measurement target position _Pc and the first detection position P1 is denoted as _Ra1, and thermal resistance connected in parallel between the first detection position P1 and the external arbitrary position _Pout. The thermal resistance obtained by synthesizing is expressed as R _a2 . Further, a thermal resistance obtained by combining the thermal resistances connected in parallel between the measurement target position _Pc and the second detection position P2 is denoted as R _b1, and is connected in parallel between the second detection position P2 and the external arbitrary position _Pout . The thermal resistance obtained by synthesizing the thermal resistance is expressed as R _b2 .

In addition, the temperature of the measurement target position P _c is referred to as “internal temperature” and expressed as T _c . The temperature at the external arbitrary position P _out is referred to as “external temperature” and is expressed as T _out . Further, the detected temperature of the first temperature sensor 11 and the second temperature sensor 12, respectively referred to as a first detected temperature and the second detection temperature, referred to as T _a and T _b, respectively.

In the heat flow path model of FIG. 1 (3), the first detected temperature _Ta is expressed by the following equation (1) using the thermal resistances _Ra1 and _Ra2 , the internal temperature _Tc, and the external temperature _Tout. Can be expressed as Further, the second detected temperature T _b can be written as the following equation (2) using the thermal resistances R _b1 and R _b2 , the internal temperature T _c, and the external temperature T _out .

In order to obtain the internal temperature T _c , the term of the external temperature T _out is deleted from the equations (1) and (2). As shown in the following equation (3), the coefficient of ambient temperature T _out in equation (1), and a coefficient of ambient temperature T _out in equation (2), as the following equations (3) and (4) replace.

The coefficient a is expressed as a ratio of the thermal resistance _Ra1 to the total thermal resistance of the first heat flow path. This represents the influence of the heat balance that the heat flow flowing through the first heat flow path receives by the thermal resistance _Ra1 , and can be considered as a coefficient representing the heat balance characteristics at the first detection position P1. The same applies to the coefficient b.

At this time, the equations (1) and (2) can be rewritten as the following equations (5) and (6), respectively.

Therefore, the internal temperature T _c can be expressed by the following equation (7) from the equations (5) and (6), for example.

Here, a heat balance relative coefficient D represented by the following expression (8) is introduced as a ratio of the coefficient a defined by the expression (3) and the coefficient b defined by the expression (4).

The heat balance relative coefficient D is a coefficient (relative value of the coefficient a and the coefficient b) representing the relative relationship of the heat balance characteristics at the first detection position P1 and the second detection position P2. At this time, using the heat balance relative coefficient D, the equation (7) can be rewritten as the following equation (9).

In Expression (9), the first detection temperature _Ta and the second detection temperature _Tb are known because they can be detected by the first temperature sensor 11 and the second temperature sensor 12, respectively. However, since the thermal resistances R _a1 , R _a2 , R _b1 , R _b2 of the first heat flow path and the second heat flow path are unknown, the value of the heat balance relative coefficient D is also unknown. Therefore, in this embodiment, the value of the heat balance relative coefficient D is calibrated.

When equation (9) is solved with respect to the heat balance relative coefficient D, the following equation (10) is obtained.

As can be seen from the equation (10), the heat balance relative coefficient D is calculated using the difference between the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 with respect to the internal temperature T _c of the measured object. The internal temperature T _c of the measured object is the temperature to be measured, and its value is unknown. However, if the internal temperature _Tc can be measured separately, the heat balance relative coefficient D can be obtained from the equation (10), and therefore the heat balance relative coefficient D can be calibrated.

For example, a reference internal temperature (hereinafter referred to as “reference internal temperature”) T _co can be measured using an invasive or non-invasive temperature measurement method.

Assuming that the detected temperatures of the first and second temperature sensors 11 and 12 when the reference internal temperature T _co is obtained are the reference first detection temperature T _ao and the reference second detection temperature T _bo , respectively, Utilizing this, the heat balance relative coefficient D can be calculated as in the following equation (11).

The value of the heat balance relative coefficient D calculated according to the equation (11) is stored. Then, after that, the first detection temperature _Ta and the second detection temperature _Tb are continuously measured, the measured first detection temperature _Ta and second detection temperature _Tb , the heat balance relative coefficient D, Is used to calculate continuously the internal temperature T _{C of the} object to be measured according to the equation (9).

1-2. Installation Position of Temperature Sensor With reference to FIG. 2 (FIG. 2 (1) to FIG. 2 (4)), the installation position of the temperature sensor will be described. Basically, the first temperature sensor 11 and the second temperature sensor 12 may be installed at any two different locations in the contact 100 as shown in FIG. Since it is physically impossible to install two different temperature sensors at the same position, the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 may be basically different temperatures. is assumed. That is, it is assumed that there is a temperature difference between the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 even if they are small. Therefore, the internal temperature of the measured object can be calculated according to the above principle.

However, if the detected temperatures of the first and second temperature sensors 11 and 12 accidentally become the same value, the internal temperature may not be calculated appropriately. According to Equation (11), when the reference first detection temperature T _ao and the reference second detection temperature T _bo are equal (T _ao = T _bo ), the heat balance relative coefficient D is “1” (D = 1). In this case, since the denominator of each term on the right side of Equation (9) is 0, the internal temperature T _c cannot be calculated. In view of such a problem, in the present embodiment, the first temperature sensor 11 and the second temperature sensor 12 are provided at positions in the contactor 100 that have different heat balance characteristics from the outside of the contactor 100. This corresponds to providing a plurality of temperature sensors at positions in the contact that differ in heat balance characteristics from the outside of the contact.

“T _ao = T _bo ” is the case where, for example, “R _a1 = R _b1 and R _a2 = R _b2 ” is established in the heat flow path model of FIG. Therefore, in principle, the first temperature sensor 11 and the second temperature sensor 12 are installed at two locations in the contact 100 such that “R _a1 ≠ R _b1 ” or “R _a2 ≠ R _b2 ”. A difference can be produced in the detected temperature of each temperature sensor. In other words, assuming a heat flow path from the heat source to the outside world, if the first temperature sensor 11 and the second temperature sensor 12 are installed at positions where the heat conduction characteristics from the heat source to the position are different, “R _a1 ≠ R _b1 ”. It becomes. Further, if the first temperature sensor 11 and the second temperature sensor 12 are installed at positions where the heat conduction characteristics from the position to the outside are different, “R _a2 ≠ R _b2 ”. In the present embodiment, the heat conduction characteristic means a heat conduction characteristic determined by a characteristic value representing heat conduction, such as heat conductivity (thermal conductivity) or a thermal resistivity that is the reciprocal thereof.

Based on this knowledge, in this embodiment, the installation position of the temperature sensor is positioned by paying attention to the physical structure of the contactor 100. Specifically, (1) the first temperature sensor 11 and the second temperature sensor at positions (hereinafter referred to as “first position conditions”) having different heat conduction characteristics from the contact surface ST of the contact 100 to the position. If 12 is installed, there is a high possibility that “R _a1 ≠ R _b1 ”. Further, (2) the first temperature sensor 11 and the second temperature sensor 12 are installed at a position (hereinafter referred to as “second position condition”) having different heat conduction characteristics from the side surface other than the contact surface ST to the position. In this case, there is a high possibility that “R _a2 ≠ R _b2 ”. Therefore, it is preferable to determine the installation position of the temperature sensor so as to satisfy the first position condition, the second position condition, or both the first position condition and the second position condition. This is because the contact is (1) a position where the heat conduction characteristic from the contact surface contacting the object to be measured differs from the position, (2) a position where the heat conduction characteristic from the side surface other than the contact surface is different from the position Or it corresponds to having a temperature sensor in the position of (1) and (2).

  Some examples that satisfy the above conditions are listed below. For example, as shown in FIG. 2B, the distance from the contact surface ST to the first temperature sensor 11 is LA, and the distance from the contact surface ST to the second temperature sensor 12 is LB (<LA). Determine the installation location. Here, the installation positions of the first temperature sensor 11 and the second temperature sensor 12 are determined along the normal direction of the contact surface ST. In this case, since the distances from the contact surface ST to the installation positions of the temperature sensors 11 and 12 are different, the heat balance characteristics at the positions of the temperature sensors 11 and 12 are different. Therefore, a difference (temperature difference) can be generated between the two detected temperatures.

  Another example is shown in FIG. The first temperature sensor 11 is disposed at the center of the contact 100 and the second temperature sensor 12 is disposed near the periphery of the contact 100. However, both the first temperature sensor 11 and the second temperature sensor 12 have substantially the same distance from the contact surface ST. In this case, the first temperature sensor 11 has a distance L1 from the side surface other than the contact surface ST of the contact 100 to the nearest side surface (upper side surface in the figure). The second temperature sensor 12 has a distance L2 (<L1) to the nearest side surface (the right side surface in the figure) among the side surfaces other than the contact surface ST of the contact 100. In this case, the heat balance characteristics at the positions of the temperature sensors 11 and 12 are different, and a difference can be generated between the two detected temperatures.

  Moreover, it is good also as an arrangement | positioning position like FIG. 2 (4) which combined the example of FIG. 2 (2) and FIG. 2 (3).

1-3. Configuration Example of Contact FIG. 3 (FIGS. 3 (1) to 3 (4)) and FIG. 4 (FIGS. 4 (1) and 4 (2)) schematically show some configurations of the contact 100. FIG. It is the figure shown, and it has illustrated as sectional drawing.

  FIG. 3A is a diagram illustrating a schematic configuration of a contact 100 </ b> A as a simplest configuration example of the contact 100. The contact 100A of FIG. 3A is configured by installing a first temperature sensor 11 and a second temperature sensor 12 at different positions inside the base 10 made of silicon rubber or the like. The method of determining the installation position of each temperature sensor is as described with reference to FIG. 2, and the same applies to FIGS. 3 (2) to 3 (4).

  FIG. 3B is a diagram illustrating a schematic configuration of the contact 100B. In the contact 100B, the exterior portion 20A is formed in a box shape made of, for example, plastic, the first temperature sensor 11 and the second temperature sensor 12 are fixed inside the base portion 20 with a string-like member, and a predetermined gas is Enclosed and configured. The inside of the base portion 20 is also considered as an inner layer portion 20B, and is filled and sealed with a gas (for example, helium gas) having a predetermined thermal conductivity.

  FIG. 3 (3) is a diagram showing a schematic configuration of the contact 100C. The contact 100C is configured by laminating a first layer 30A and a second layer 30B made of materials having different bases 30 in thermal conductivity. As materials for the first layer 30A and the second layer 30B, materials having different thermal conductivities can be appropriately selected. The first temperature sensor 11 is installed in the first layer 30A, and the second temperature sensor 12 is installed in the second layer 30B.

  FIG. 3 (4) is a diagram showing a schematic configuration of the contact 100D. In the contact 100D, a first layer 40A in which a circuit board 40C having a first temperature sensor 11 disposed on an upper surface and a second temperature sensor 12 disposed on a lower surface is included and fixed with a resin or the like, and a second layer 40B are laminated. A base 40 is included. It is possible to further mount a processor and a memory on the circuit board 40C. In that case, the first temperature sensor 11 and the second temperature sensor 12 may be provided at a position away from the heating element.

  FIGS. 4A and 4B are configuration examples of the contact 100 when a non-contact temperature sensor such as an infrared temperature sensor is used as the temperature sensor. The contact 100E shown in FIG. 4 (1) has a configuration in which the base 50 formed in a cup shape is turned upside down so as to come into contact with the object to be measured, and the inner bottom surface of the base 50 (the surface facing the surface of the object to be measured) ) Having a first temperature sensor 11 and a second temperature sensor 12. Moreover, the 1st temperature sensor 11 is installed in the position near the periphery of the base 50, and the 2nd temperature sensor 12 is installed in the center part.

  The first temperature sensor 11 and the second temperature sensor 12 detect the temperatures of the detection positions P1 and P2 on the surface of the measured object, respectively. Since the 1st temperature sensor 11 is installed near the circumference of base 50, it is easy to be influenced by the heat balance between the outside compared with the 2nd temperature sensor 12. Therefore, a difference may occur between the detected temperatures of the first and second temperature sensors 11 and 12.

  In the contact 100F of FIG. 4B, the exterior portion 60A is formed as a box-shaped body made of, for example, plastic, and the first temperature sensor 11 and the second temperature sensor 12 are installed on the ceiling surface of the interior 60B of the base portion 60. Configured.

  In addition, the first pedestal portion 60C and the second pedestal portion formed of materials having different thermal conductivities are provided on the bottom surface of the interior 60B of the base portion 60 and at positions opposed to the first temperature sensor 11 and the second temperature sensor 12, respectively. 60D is provided. The first temperature sensor 11 and the second temperature sensor 12 detect the temperatures of the detection positions P1 and P2 of the first pedestal portion 60C and the second pedestal portion 60D, respectively. Since the first pedestal portion 60C and the second pedestal portion 60D have different thermal conductivities, there may be differences in the detected temperatures of the temperature sensors 11 and 12, respectively.

1-4. Experimental Results FIG. 5 is a diagram showing an example of experimental results performed in accordance with the temperature calculation principle described above. The object to be measured is warm water, a base of 20 [mm] thickness made of polyvinyl chloride (PVT) is placed on the hot water, and the contact 100 of FIG. The temperature of was calculated. The contact 100 used in this experiment is formed by molding a silicone rubber into a button shape having a diameter of 40 [mm] and a height of 5 [mm]. A thermistor was used for the first temperature sensor 11 and the second temperature sensor 12. Moreover, the temperature of warm water was changed in the range of 32 [° C.] to 44 [° C.].

  In FIG. 5, the horizontal axis is the actual measured water temperature, and the vertical axis is the calculated water temperature. All units are [° C.]. When this graph is seen, it turns out that the water temperature actual value and the water temperature calculation value show the linear characteristic, and the water temperature is calculated correctly. When attention is paid to the result of the portion surrounded by the dotted line, the measured water temperature is 36.922 [° C.] with respect to the measured water temperature of 36.922 [° C.], and the calculation error is 0.08 [ %] Of −0.031036 [° C.]. From this experimental result, the effectiveness of the temperature calculation method of this embodiment was proved.

2. Example Next, an example of the temperature measurement system 1 that calculates and measures the internal temperature of the measurement object according to the above principle will be described. Here, a case where the body to be measured is a human body and the contactor 100 is brought into contact with the surface of any part of the head, neck, and trunk and the temperature at the measurement target position is measured will be described as an example.

2-1. Functional Configuration FIG. 6 is a block diagram illustrating an example of a functional configuration of the temperature measurement system 1 in the present embodiment. The temperature measurement system 1 includes a contact 100 and a main body device 200.

  The basic configuration of the contact 100 is as described above. As a configuration as an example, a plastic cover portion (not shown) that holds the contact surface ST of the base portion 10 that is in contact with the skin surface of the human body, which is a measurement object, is exposed, and is configured as a probe, for example. Is done. The contact 100 may have a planar shape (for example, a button shape or a sheet shape) as a whole, or a cylindrical shape that can be held with one hand.

  The contact 100 and the main body device 200 may be wired by a cable, or may be configured to be wirelessly connected to the main body device 200 by incorporating a small wireless device in the contact 100. . Further, in order to fix the contact 100 to the human body torso and neck, a configuration may be provided that includes a belt wound around the body torso and neck, or a configuration in which a replaceable adhesive tape can be attached.

  The main device 200 includes, for example, a processing unit 300, an operation unit 400, a display unit 500, a communication unit 600, and a storage unit 800.

  The processing unit 300 is a control device and an arithmetic device that collectively control each unit of the temperature measurement system 1 according to various programs such as a system program stored in the storage unit 800. For example, a CPU (Central Processing Unit) or DSP (Digital Signal Processor) and the like.

  The processing unit 300 inputs temperature detection signals from the first temperature sensor 11 and the second temperature sensor 12 in the contact 100. Then, based on the temperature detection signal, the detection temperatures of the first detection position P1 and the second detection position P2 are acquired and stored in the storage unit 800.

  The processing unit 300 includes an initial calibration unit 310 and an internal temperature calculation unit 320 as main functional units. The initial calibration unit 310 includes a relative relationship determination unit 311 as a functional unit. The relative relationship determination unit 311 corresponds to a determination unit that determines the relative relationship of the heat balance characteristics at the respective positions of the plurality of temperature sensors. The internal temperature calculation unit 320 corresponds to a temperature calculation unit that continuously calculates the internal temperature of the measurement object.

  The operation unit 400 is an input device that includes a switch and the like, and outputs a signal of the pressed switch to the processing unit 300. The operation unit 400 is used by the user to input various reference operations such as measurement start and measurement end of the internal temperature, in addition to being used for inputting a reference internal temperature for initial calibration.

  The display unit 500 is a display device that includes an LCD (Liquid Crystal Display) or the like and performs various displays based on display signals input from the processing unit 300. The display unit 500 displays the measurement result of the internal temperature of the object to be measured.

  The communication unit 600 is a communication device for transmitting and receiving information used inside the device to and from an external information processing device such as a PC (Personal Computer) under the control of the processing unit 300. As a communication method of the communication unit 600, various methods such as a wired connection type via a cable compliant with a predetermined communication standard and a wireless connection type using short-range wireless communication can be applied.

  The storage unit 800 includes a storage device such as a ROM (Read Only Memory), a flash ROM, and a RAM (Random Access Memory). The storage unit 800 stores a system program of the temperature measurement system 1, various programs for realizing various functions such as an initial calibration function, a temperature calculation function, and a communication function, data, and the like.

  The storage unit 800 stores a first main program 810 that is read as a program by the processing unit 300 and executed as a first main process (see FIG. 7). The first main program 810 includes an initial calibration program 811 executed as an initial calibration process and an internal temperature calculation program 812 executed as an internal temperature calculation process as subroutines. These processes will be described later in detail using a flowchart.

  The storage unit 800 also stores data for initial calibration 820, detected temperature data 830, a heat balance relative coefficient 840, and a calculated internal temperature 850 as data.

  The initial calibration data 820 is data for performing initial calibration of the temperature measurement system 1, and includes a reference first detection temperature 821, a reference second detection temperature 822, and a reference internal temperature 823.

  The detected temperature data 830 is detected temperature data acquired based on the temperature detection signals input from the first temperature sensor 11 and the second temperature sensor 12, and the first detected temperature 831 and the second detected temperature 832 include the detected temperature data. include.

  The heat balance relative coefficient 840 is a value of the heat balance relative coefficient D calculated according to the equation (11) using the initial calibration data 820.

  The calculated internal temperature 850 is an internal temperature continuously calculated according to the equation (9) using the detected temperature data 830 and the heat balance relative coefficient 840.

2-2. Usage example The temperature measurement system 1 is, in principle, performing an initial calibration with the contact 100 in contact with the surface of a human body whose internal temperature is to be measured, and continuously calculating the internal temperature in that state. is there. In the present embodiment, the contact 100 is installed so as to come into contact with the surface of a part that changes in temperature relative to any part of the head, neck, and body part that shows the deep body temperature.

  For example, when it is desired to measure the esophageal temperature, the contact 100 is fixed to the skin surface of the neck, and the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 are calculated in this state, and the reference first detected temperature 821 And the reference second detection temperature 822. Further, for example, a catheter having a thermistor sealed at the tip is inserted into the esophagus to measure the esophageal temperature, and the measurement temperature is set as a reference internal temperature 823. Alternatively, the esophageal temperature may be measured using a heat flow compensation formula.

  Then, the relative relationship determination unit 311 calculates the heat balance relative coefficient 840 according to the equation (11) using the reference first detection temperature 821, the reference second detection temperature 822, and the reference internal temperature 823. Thereafter, the esophageal temperature is calculated according to Equation (9) using the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 and the heat balance relative coefficient 840 calculated in advance.

  Although the above usage is a basic usage example, as an application example, a position away from the installation position of the contact 100 may be set as a measurement target position. For example, when the rectal temperature is measured using the rectum as a measurement target position, the position where the contact 100 is installed is an arbitrary position as long as the temperature of the contact 100 is relatively changed between the rectum and the measurement target position. Good. Of the human body, parts other than the extremities such as the head, neck, and trunk are core parts that maintain constant temperature, and thus the surfaces of these parts are suitable.

  In this case as well, the reference internal temperature 823 needs to be the temperature at the measurement target position. That is, in order to set the rectum as the measurement target position, the rectal temperature is measured using a predetermined temperature measurement method. For example, a method of measuring the rectal temperature by inserting a thermistor probe from the anus, a method of measuring the rectal temperature using a heat flow compensation formula, or the like can be used.

  Using the reference internal temperature 823 measured separately and the reference first detection temperature 821 and the reference second detection temperature 822 calculated and acquired from the contactor 100 at the time of measurement, the heat balance relative coefficient 840 is calculated according to the equation (11). To do. This is the initial calibration. Thereafter, the rectal temperature can be continuously calculated according to the equation (9) using the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 and the calculated heat balance relative coefficient 840.

2-3. Process Flow FIG. 7 is a flowchart showing the flow of the first main process executed by the processing unit 300 of the main device 200 according to the first main program 810 stored in the storage unit 800.

  First, the processing unit 300 performs an initial calibration process according to the initial calibration program 811 stored in the storage unit 800. In the initial calibration process, the processing unit 300 functions as the initial calibration unit 310.

  The initial calibration unit 310 receives the reference internal temperature 823 and sets it as the initial calibration data 820 (step A1). For example, the reference internal temperature 823 that is input from the operation unit 400 or input from an external measurement device is stored in the storage unit 800.

  Next, the initial calibration unit 310 receives a temperature detection signal from the contact 100, calculates the detection temperature of each temperature sensor, and stores it in the storage unit 800 as the reference first detection temperature 821 and the reference second detection temperature 822 ( Step A5).

  Thereafter, the relative relationship determination unit 311 calculates the heat balance relative coefficient 840 according to the equation (11) using the reference first detection temperature 821, the reference second detection temperature 822, and the reference internal temperature 823, and the storage unit 800 (step A9). Then, the initial calibration unit 310 ends the initial calibration process.

  If the initial calibration process is performed, the processing unit 300 performs the internal temperature calculation process according to the internal temperature calculation program 812 stored in the storage unit 800. In the internal temperature calculation process, the processing unit 300 functions as the internal temperature calculation unit 320.

  The internal temperature calculation unit 320 receives the temperature detection signal from the contact 100, calculates the detection temperature of each temperature sensor, and stores it in the storage unit 800 as the first detection temperature 831 and the second detection temperature 832 (step A13). .

  Then, the internal temperature calculation unit 320 calculates the internal temperature according to the equation (9) using the first detection temperature 831, the second detection temperature 832, and the heat balance relative coefficient 840 and stores it as the calculated internal temperature 850. The data is stored in the unit 800 (step A17). And the internal temperature calculation part 320 complete | finishes an internal temperature calculation process.

  When the internal temperature calculation process is performed, the processing unit 300 displays the calculated internal temperature 850 obtained in step A17 on the display unit 500 (step A21). Then, the processing unit 300 determines whether or not to end the temperature measurement (step A25). For example, when a temperature measurement end instruction operation is performed by the user via the operation unit 400, it is determined that the temperature measurement is to be ended.

  If it determines with continuing a temperature measurement (step A25; No), the process part 300 will return to step A13. If it is determined that the temperature measurement is to be ended (step A25; Yes), the processing unit 300 ends the first main process.

2-4. Operational Effect In the temperature measurement system 1, the relative relationship determination unit 311 includes a reference internal temperature 823, which is an internal temperature of the measured object separately measured, and a first temperature sensor when the contact 100 is brought into contact with the measured object. 11 shows the relative relationship of the heat balance characteristics at the respective positions of the temperature sensors 11 and 12, using the reference first detection temperature 821 and the reference second detection temperature 822, which are detection temperatures of the temperature sensor 11 and the second temperature sensor 12, respectively. A heat balance relative coefficient 840 is calculated. And the internal temperature calculation part 320 calculates the internal temperature of a to-be-measured body continuously using the heat balance relative coefficient 840 and each detection temperature of each temperature sensor 11 and 12. FIG.

  If the heat balance relative coefficient 840 can be initially calibrated, using the first detected temperature 831 and the second detected temperature 832 detected by the temperature sensors 11 and 12 and the heat balance relative coefficient 840, the equation (9) The internal temperature can be calculated from In this method, the detected temperature detected by each of the temperature sensors 11 and 12 in a state where the contact 100 is in contact with the measured object and the internal temperature of the measured object separately measured are used. The internal temperature of the measurement object can be calculated easily. In addition, since the internal temperature is calculated in consideration of the heat balance characteristics at the respective positions of the temperature sensors 11 and 12, temperature measurement errors due to the heat balance can be compensated together.

  Moreover, each temperature sensor 11 and 12 is provided in the position in which the heat balance characteristic in the contactor 100 and the contactor 100 exterior differs. Paying attention to the physical structure of the contactor 100, the contactor 100 includes (1) a position where the heat conduction characteristics from the contact surface in contact with the object to be measured to the position differ, and (2) a side surface other than the contact surface. Each of the temperature sensors 11 and 12 is provided at a position where the heat conduction characteristics up to the position are different, or at the positions (1) and (2). Thereby, the heat balance characteristic in each position of each temperature sensor 11 and 12 can be varied, and a difference (temperature difference) can be produced in the detected temperature of each temperature sensor 11 and 12. As the temperature difference is larger, the relative relationship of the heat balance characteristics at the respective positions of the temperature sensors 11 and 12 is more clearly reflected in the heat balance relative coefficient D. As a result, the internal temperature can be calculated with high accuracy from the equation (9).

3. Modifications Embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit of the present invention. Hereinafter, although a modification is demonstrated, the same code | symbol is attached | subjected about the same structure as said Example, and the same step of a flowchart, and repeated description is abbreviate | omitted.

3-1. Number of temperature sensors installed In the above embodiment, the case where two temperature sensors are installed inside the contactor 100 has been described as an example, but three or more temperature sensors may be installed at different positions. Good. In this case, the heat flow path model described in FIG. 1 may be modeled in the same manner as in the above embodiment, assuming a heat flow path corresponding to the number of temperature sensors to be installed.

  That is, when n temperature sensors are installed in the contact 100, a heat flow path model similar to that in FIG. 1 (3) is constructed for each of the first to nth heat flow paths. Then, formulas of temperatures at the respective positions of the first to nth detection positions are formulated. And the relative relationship of the heat balance characteristic in each position of the 1st-nth detection position is defined as a heat balance relative coefficient, respectively. After that, the internal temperature may be calculated after calibrating the heat balance relative coefficient as in the above embodiment.

3-2. Selection of Temperature Sensor In addition, three or more temperature sensors may be installed in different positions in the contact 100, and at least two temperature sensors may be selected from among them to calculate the internal temperature. For example, when three temperature sensors are installed, two temperature sensors are selected from among them and the internal temperature is calculated. Further, for example, when four temperature sensors are installed, two or three temperature sensors may be selected from among them and the internal temperature may be calculated. Here, a case where three temperature sensors are installed in the contact 100 will be described as an example.

  FIG. 8A is a diagram illustrating an example of a schematic configuration of the contact 100G in the present modification. The contact 100G is configured by providing first to third temperature sensors 11, 12, 13 at first to third detection positions P1, P2, P3 in the base 10, respectively.

  FIG. 8B is a diagram illustrating a functional configuration of the processing unit 300 of the main body device 200 according to the present modification. The processing unit 300 further includes a temperature sensor selection unit 313 in addition to the initial calibration unit 310. The temperature sensor selection unit 313 is a selection unit that selects two temperature sensors from the three temperature sensors.

  FIG. 9 is a flowchart showing the flow of the second main process executed by the processing unit 300 of FIG. 8B in place of the first main process of FIG.

  First, the processing unit 300 executes a second initial calibration process. The initial calibration unit 310 sets the reference internal temperature (step A1), and then calculates the detected temperatures of the first to third temperature sensors 11 to 13 (step B3). Then, for each combination of two temperature sensors, a calculated difference in detected temperature (hereinafter referred to as “detected temperature difference”) is calculated (step B5).

  Next, the temperature sensor selection unit 313 determines a temperature sensor used for temperature measurement (hereinafter referred to as “measurement use temperature sensor”) based on the detected temperature difference calculated in step B5 (step B7). Specifically, for example, a combination of temperature sensors having the maximum detected temperature difference is determined, and two temperature sensors that are the combinations are selected as measurement use temperature sensors. This is because, as described in the above embodiment, it is appropriate to calibrate the heat balance relative coefficient D so that the temperature difference between the two points is as large as possible.

  Next, the relative relationship determination unit 311 sets the detected temperatures detected for the measurement use temperature sensor selected in step B7 as the reference first detection temperature and the reference second detection temperature, and sets these reference detection temperatures and the step A1. Using the reference internal temperature, the heat balance relative coefficient is calculated according to the equation (11) (step A9). Then, the initial calibration unit 310 ends the second initial calibration process.

  Thereafter, the processing unit 300 performs a second internal temperature calculation process. The internal temperature calculation unit 320 calculates the detection temperature of the measurement use temperature sensor selected in step B7, and sets the first detection temperature and the second detection temperature, respectively (step B13). The internal temperature calculation unit 320 calculates the internal temperature according to the equation (9) using the first detection temperature and the second detection temperature and the heat balance relative coefficient calculated in step A9 (step A17). The second internal temperature calculation process is terminated. The subsequent steps are the same as those in the first main process.

3-3. Calculation formula of heat balance relative coefficient and internal temperature The calculation formula of heat balance relative coefficient and internal temperature described in the above embodiment is merely an example, and is not limited thereto. For example, in the above embodiment, the heat balance relative coefficient D defined as in Expression (8) can be defined as the heat balance relative coefficient F in the following Expression (12).

In this case, the equation (7) can be rewritten as the following equation (13) using the heat balance relative coefficient F.

The equation (13) is solved for the heat balance relative coefficient F and the reference internal temperature T _co , the reference first detection temperature T _ao and the reference second detection temperature T _bo are substituted, and the heat balance is obtained as in the following equation (14). The relative coefficient F can be calculated.

Further, when the external temperature T _out is erased from the equations (5) and (6), the following equation (15) can be derived by changing the erase procedure.

Based on the equation (15), the heat balance relative coefficient G can be defined as the following equation (16).

In this case, the equation (15) can be expressed as the following equation (17).

The equation (17) is solved for the heat balance relative coefficient G, and the reference internal temperature T _co , the reference first detection temperature T _ao, and the reference second detection temperature T _bo are respectively substituted, so that the heat as shown in the following equation (18) is obtained. The balance relative coefficient G can be calculated.

The above heat balance relative coefficients F and G are both the ratio of the total thermal resistance existing in the first heat flow path to the thermal resistance _Ra1 (coefficient a) and the total thermal resistance existing in the second heat flow path. Of these, it is expressed as a ratio to the ratio (coefficient b) occupied by the thermal resistance R _b1 . The heat balance relative coefficients F and G are both calculated based on the difference between the reference detected temperatures T _ao and T _bo of the temperature sensors 11 and 12 with respect to the reference internal temperature T _co . Regardless of which calculation formula is used to calculate the heat balance relative coefficient and the internal temperature, the calculation result of the internal temperature finally obtained is the same.

3-4. Processing when there is no difference in detected temperature In the above embodiment, by installing temperature sensors at two different locations in the contactor 100, the heat balance characteristics at the positions of the temperature sensors are made different. It was. However, depending on the case, there may be a case where there is no difference in the heat balance characteristics at the position of each temperature sensor and no difference in the detected temperature of each temperature sensor. In this case, the internal temperature can be calculated as follows.

よって、「Ｔ_a＝Ｔ_b」が成立する場合は、内部温度を「Ｔ_c＝Ｔ_a＝Ｔ_b」として求めることができる。 When installing the first temperature sensor 11 and the second temperature sensor 12 in two places in the contact 100, if the first detected temperature T _a is the detected temperature and the second detected temperature T _b is equal (T _a = T _b ) and equation (7) can be rewritten as the following equation (19).

Therefore, when “T _a = T _b ” is established, the internal temperature can be obtained as “T _c = T _a = T _b ”.

  FIG. 10 is a flowchart showing the flow of the third main process executed by the processing unit 300 of FIG. 6 in place of the first main process of FIG.

  The processing unit 300 determines whether or not there is a difference between the detected temperatures of the first temperature sensor 11 and the second temperature sensor 12 calculated in step A13 in the third internal temperature calculation process related to the calculation of the internal temperature. (Step C15). In this determination, it is determined that there is no difference in the detected temperature not only when the detected temperature difference is “0” but also when the detected temperature difference is a very small value close to “0”. It is good as well.

  When it is determined in step C15 that there is a difference in the detected temperature (step C15; Yes), the internal temperature calculation unit 320 calculates the first detected temperature 831, the second detected temperature 832, and the heat balance relative coefficient 840. The internal temperature is calculated according to the equation (9), and is stored in the storage unit 800 as the calculated internal temperature 850 (step A17). And the internal temperature calculation part 320 complete | finishes a 3rd internal temperature calculation process.

  On the other hand, when it is determined in step C15 that there is no difference in the detected temperature (step C15; No), the internal temperature calculation unit 320 uses, for example, the first detected temperature 831 as the internal temperature and stores it as the calculated internal temperature 850. The data is stored in the unit 800 (step C19). And the internal temperature calculation part 320 complete | finishes a 3rd internal temperature calculation process.

3-5. Reference internal temperature In the above embodiment, the reference internal temperature has been described as being measured using a predetermined temperature measurement method. However, when the temperature is simply calculated, model value data obtained by statistically processing a reference internal temperature measured in the past may be stored in the storage unit 800 and used. For example, the model value of the reference internal temperature classified into gender, age, and the like is stored in the storage unit 800 of the main device 200. In the initial calibration, the value of the heat balance relative coefficient is calculated using the model value that matches the sex, age, etc. of the user input as an operation as the reference internal temperature.

DESCRIPTION OF SYMBOLS 1 Temperature measurement system, 100 Contact, 200 Main body apparatus, 300 Processing part,
400 operation unit, 500 display unit, 600 communication unit, 800 storage unit

Claims (4)

A contactor having a first temperature sensor and a second temperature sensor and in contact with an object to be measured;
In the first heat flow path from the measurement target position of the measurement object to the position outside the contact through the first detection position in the contact where the first temperature sensor is installed, from the measurement target position The thermal resistance up to the first detection position is Ra1, and the position outside the contact through the second detection position in the contact where the second temperature sensor is installed from the measurement target position of the measured object. When the thermal resistance from the measurement target position to the second detection position is Rb1, the thermal resistance Ra1 with respect to the thermal resistance from the measurement target position to a position outside the contact is determined. A heat balance relative coefficient representing a ratio between a first heat balance characteristic that is a ratio and a second heat balance characteristic that is a ratio of the thermal resistance Rb1 to a thermal resistance from the measurement target position to a position outside the contact. Memorize And parts,
Based on the heat balance relative coefficient, the first detected temperature that is the detected temperature of the first temperature sensor, and the second detected temperature that is the detected temperature of the second temperature sensor, the internal temperature of the measured object is determined. An internal temperature calculation unit to calculate,
The first temperature sensor and the second temperature sensor are provided at a position where the thermal resistance Ra1 and the thermal resistance Rb1 are different from each other. The first temperature sensor and the second temperature sensor are: (1) a position having different heat conduction characteristics from the contact surface that contacts the measurement object to the position, and (2) a side surface other than the contact surface to the position. Are provided at different positions, or (1) and (2).
The temperature measurement system according to claim 1. The contact has a plurality of layers having different heat conduction characteristics,
The first temperature sensor and the second temperature sensor are provided in layers having different heat conduction characteristics from each other,
The temperature measurement system according to claim 1 or 2. A temperature calculation method for calculating the internal temperature of the object to be measured using the contact having a first temperature sensor and the second temperature sensor provided in contact child in contact with the object to be measured,
The first temperature sensor and the second temperature sensor are positioned outside the contact through a first detection position in the contact where the first temperature sensor is installed from a measurement target position of the measured object. In the first heat flow path leading to, the thermal resistance from the measurement target position to the first detection position is Ra1, and from the measurement target position of the object to be measured, the second temperature sensor is installed in the contactor. In the second heat flow path that reaches the position outside the contact through the second detection position, when the thermal resistance from the measurement target position to the second detection position is Rb1, the thermal resistance Ra1 and the thermal resistance Rb1 is provided at a different position,
The first heat balance characteristic which is a ratio of the thermal resistance Ra1 to the thermal resistance from the measurement target position to a position outside the contact, and the thermal resistance with respect to the thermal resistance from the measurement target position to a position outside the contact A heat balance relative coefficient representing a ratio to the second heat balance characteristic that is a ratio of Rb1, a first detected temperature that is a detected temperature of the first temperature sensor, and a second that is a detected temperature of the second temperature sensor. Calculating the internal temperature of the measured object based on the detected temperature;
Temperature calculation method including

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