Probe for deep temperature measurement and deep thermometer

Abstract

In the present invention, a probe 1 for deep temperature measurement used to measure the temperature of the depth of a subject 9 comprises a plate-shaped substrate 10, a pair of first area temperature sensors 21, 22 mounted on a first area 11 of the substrate so as to face each other across the substrate 10, and a pair of second area temperature sensors 23, 24 mounted on a second area 12 of the substrate so as to face each other across the substrate 10. A through hole 15 penetrating between the observe surface 10a and the reverse surface 10b of the substrate 10 immediately below the first area temperature sensors 21, 22 is formed in the substrate 10, and the through hole 15 connects between the pair of first area temperature sensors 21, 22. The probe 1 for deep temperature measurement makes it possible to measure the temperature of the depth of a subject at a high accuracy, even if the thickness of the substrate constituting the probe is reduced.

Description

Deep temperature measurement probe and deep thermometer

[0001] The present invention relates to a deep temperature measurement probe and a deep thermometer, and particularly to a deep temperature measurement probe and a deep thermometer that measure the deep temperature (core temperature) of a human body.

[0002] The dual heat flow method, a non-invasive method for measuring the temperature deep inside the human body, has been studied. The dual heat flow method measures the heat flow through two different insulating materials and solves simultaneous equations related to the heat flow to determine the deep temperature TB without using the unknown thermal resistance value of the skin (see, for example, Non-Patent Document 1).

[0003] Non-Patent Document 1 and Patent Document 1 disclose a deep temperature measurement probe (hereinafter, sometimes simply referred to as a "probe") that measures deep temperature TB using the dual heat flow method. In order to configure a probe for the total heat flow method, it is essential to provide a difference between the thermal resistance values ​​of the two heat paths (between the thermal resistance value of the first heat path and the thermal resistance value of the second heat path), and these documents also disclose probes that are designed for this purpose.

[0004] The deep temperature measurement probe described in Patent Document 1 is configured such that the occupancy rate and / or distribution of the conductive pattern in a first region of the substrate is different from the occupancy rate and / or distribution of the conductive pattern in a second region, thereby creating a difference in the thermal resistivity between them. For example, in the example of Figure 1, a conductive pattern is arranged between layers of the substrate in the first heat flow path to reduce the overall thermal resistance value R, while in the second heat flow path, no such interlayer conductive pattern is arranged and the second heat flow path is formed by the substrate material itself, resulting in a difference in the thermal resistance value of the two heat flows overall.

[0005] Kazunari Yanai, "Development of a Non-invasive Deep Body Thermometer and Its Verification in Basic Experiments," Master's Thesis, Graduate School of Information Science, Nara Institute of Science and Technology, NAIST Digital Library, 2014

[0006] International Publication No. 2019 / 167707

[0007] Nowadays, with the summer often experiencing extreme heat, it is expected that efforts to monitor the body's core temperature (TB, especially the core body temperature) by attaching a deep temperature measurement probe to the body will increase in the future, in order to prevent heatstroke, etc. One of the attributes expected of a wearable probe is that it is "thin," which reduces resistance to wearing it and increases the rate at which it is worn.

[0008] However, when the thickness of the substrate constituting the deep body temperature measurement probe is reduced, the dimension in the thickness direction decreases, leading to a decrease in the thermal resistance value in the thickness direction. In this case, based on the technology of the deep body temperature measurement probe described in Patent Document 1, even if a conductive pattern is inserted between the layers to reduce the thermal resistance value of the first region, the thermal resistance value of the second region is also reduced due to the thinning of the substrate, making it difficult to achieve a difference in thermal resistance value between the two regions. Therefore, even if a thin, wearable deep body temperature measurement probe is constructed using the technology described in Patent Document 1, it is difficult to maintain high accuracy in measuring and estimating deep body temperature (hereinafter simply referred to as "measurement").

[0009] Furthermore, in the deep temperature measurement probe described in Patent Document 1, the smaller the dimensions of the substrate are set, the more difficult it becomes to incorporate many conductive patterns inside, making it less feasible and practical.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a deep body thermometer measurement probe that can measure the temperature deep inside a subject with high accuracy even if the substrate constituting the probe is thinned, and also aims to provide a deep body thermometer equipped with such a deep body thermometer measurement probe.

[0011] According to one aspect of the present invention, there is provided a deep temperature measurement probe for use in measuring the temperature of a deep part of a subject. The deep temperature measurement probe includes a plate-shaped substrate, a pair of temperature sensors (a pair of first region temperature sensors) mounted in a first region of the substrate so as to face each other across the substrate, and a pair of temperature sensors (a pair of second region temperature sensors) mounted in a second region of the substrate so as to face each other across the substrate. The substrate has a through-hole formed directly below the first region temperature sensor, penetrating from the front to back surface of the substrate, and the pair of first region temperature sensors are connected by the through-hole.

[0012] According to another aspect of the present invention, a deep temperature measurement probe is provided that can be used to measure the temperature of a deep part of a subject. The deep temperature measurement probe includes a plate-shaped substrate, a pair of temperature sensors (a pair of first region temperature sensors) mounted on a first region of the substrate facing each other across the substrate, and a first heat flow measurement system having a first heat flow path formed within the substrate in the first region and measuring a first heat flow flowing out of the subject. The probe also includes a pair of temperature sensors (a pair of second region temperature sensors) mounted on a second region of the substrate facing each other across the substrate, and a second heat flow measurement system having a second heat flow path formed within the substrate in the second region and measuring a second heat flow flowing out of the subject. The substrate has a through-hole formed directly below the first region temperature sensor, penetrating from the front to back surfaces of the substrate, and the first heat flow path is configured as an air layer disposed within the through-hole.

[0013] According to yet another aspect of the present invention, there is provided a deep thermometer comprising the above-described deep temperature measurement probe and a deep temperature estimation unit that estimates deep temperatures using the temperatures measured by a pair of first region temperature sensors and a pair of second region temperature sensors of the deep temperature measurement probe.

[0014] According to the present invention, it is possible to provide a deep body thermometer measurement probe that can measure the temperature deep inside a subject with high accuracy even if the substrate constituting the probe is thinned, and it is also possible to provide a deep body thermometer equipped with such a deep body thermometer measurement probe.

[0015] 1 is a diagram shown for explaining the deep temperature measuring probe 1 according to embodiment 1. FIG. 2 is a diagram showing components of the deep temperature measuring probe 1 according to embodiment 1. FIG. 3 is a block diagram showing an example of the hardware configuration of the deep temperature thermometer 500 according to embodiment 1. FIG. 4 is a thermal equivalent circuit diagram of the deep temperature measuring probe 1 according to embodiment 1. FIG. 5 is a cross-sectional view schematically showing an experimental system for the deep temperature measuring probe 1 according to embodiment 1. FIG. 6 is a cross-sectional view showing the deep temperature measuring probe 2 according to embodiment 2. FIG. 7 is a cross-sectional view showing the deep temperature measuring probe 3 according to embodiment 3. FIG. 8 is a diagram shown for explaining the deep temperature measuring probe 4 according to embodiment 4. FIG. 9 is a cross-sectional view showing the deep temperature measuring probe 5 according to modified example 1. FIG. 10 is a cross-sectional view of the main parts of the deep temperature measuring probes 6 and 7 according to modified example 2 and modified example 3. FIG. 11 is a diagram shown for explaining the deep temperature measuring probes 4' and 4'' according to modified example 4.

[0016] The deep body temperature measuring probe and deep body thermometer according to the present invention will be described below with reference to the drawings. Note that the explanations of the reference numerals common to the figures will be omitted because the explanations of the reference numerals already given can be applied to the explanations of the other figures.

[0017] [Embodiment 1] 1. Configuration of deep temperature measuring probe 1 according to embodiment 1 FIG. 1 is a diagram shown for explaining the deep temperature measuring probe 1 according to embodiment 1. FIG. 1(a) is a cross-sectional view of the deep temperature measuring probe 1 showing the B-B cross section of FIG. 1(b). FIG. 1(b) is a plan view of the deep temperature measuring probe 1 when viewed along arrow A in FIG. 1(a). FIG. 2 is a diagram showing the components of the deep temperature measuring probe 1 according to embodiment 1.

[0018] (1) Overview of the Deep Temperature Measurement Probe 1 As shown in FIG. 1, the deep temperature measurement probe 1 is used to measure the temperature of a deep portion 9c of a subject 9, which is located deep within the subject. The probe measures the temperature of the deep portion 9c (deep temperature TB) by directly or indirectly contacting its rear surface with the subject's surface 9a. In the figure, the symbol RS indicates the thermal resistance of the subject's intermediate portion 9b, which cannot be measured directly. Typical subjects 9 include living organisms such as humans and animals, but in this embodiment, the explanation will be limited to humans. The deep temperature measurement probe 1 includes a substrate 10 and temperature sensors 21, 22, 23, and 24. Note that in this specification, the temperature sensors are sometimes simply referred to as "sensors."

[0019] (2) Board 10 FIG. 2( a) is a plan view of the board 10, showing the surface of the bare board without the temperature sensors 21, 22, 23, 24, and 25 mounted thereon. As shown in FIG. 2( a), the board 10 is a printed circuit board on which a wiring pattern 13 is formed. A glass epoxy board, for example, can be used as the board 10. The board 10 of this embodiment is a so-called double-sided board having wiring patterns 13 on both the front surface 10a and the back surface 10b. The wiring pattern 13 (wiring pattern in a broad sense) includes terminals 13c, wiring patterns 13a in a narrow sense connecting the terminals 13c, and lands 13b in a narrow sense formed in a pad shape. Note that the illustration of the wiring pattern 13a in a narrow sense omits intermediate connections.

[0020] The substrate 10 has a front surface 10a and a back surface 10b, and is, for example, plate-like. Note that the definitions of the front surface 10a and the back surface 10b here are for convenience's sake, with the surface facing the outside (atmosphere 8) being the front surface 10a and the surface abutting the test object 9 being the back surface 10b. The substrate 10 functions as a base on which the temperature sensors 21, 22, 23, and 24 are mounted, and also partially (or entirely) forms a heat flow path (heat flow path) through which heat flows from the back surface 10b side to the front surface 10a side (see also FIG. 1 ).

[0021] (3) Temperature Sensors 21, 22, 23, 24 The temperature sensors 21, 22, 23, 24 measure the temperature at the contact points (nodes) and output signals corresponding to the measured temperatures. They can be configured as discrete devices such as thermocouples, platinum resistance thermometers, thermistors, or integrated circuits (ICs) that output digital output signals. The temperature sensors 21, 22, 23, 24 in this embodiment are ICs, and may be implemented in a so-called SON package (Small Outline Non-leaded package) as shown in the figure.

[0022] 2B is a bottom view of the SON package for the temperature sensors 21, 22, 23, 24, and 25. Each of the temperature sensors 21, 22, 23, 24, and 25 includes a semiconductor chip (not shown) that senses temperature and converts it into an electrical signal. External connection terminals 28 electrically connected to the semiconductor chip are exposed on the bottom surface. Each of the temperature sensors 21, 22, 23, 24, and 25 also includes a thermal pad 29 on the bottom surface to improve thermal coupling between the contact point (specifically, the node of the heat flow path) to be measured and the internal semiconductor chip.

[0023] Returning to FIG. 1 , we will continue to explain the mounting of the temperature sensors on the board. Temperature sensors 21 and 22 are mounted in a pair in the first region 11 of the board 10, facing each other across the board 10. Temperature sensor 21 is mounted on the back surface 10b of the board 10, and temperature sensor 22 is mounted on the front surface 10a of the board 10. Similarly, temperature sensors 23 and 24 are mounted in a pair in the second region 12 of the board 10, facing each other across the board 10. Temperature sensor 23 is mounted on the back surface 10b of the board 10, and temperature sensor 24 is mounted on the front surface 10a of the board 10. Reference numeral 60 in the figure denotes an external connector for connecting to the outside. Reference numeral 25 denotes a temperature sensor for measuring the outside air temperature. As will be described later, when experimentally determining the thermal resistance ratio K, the outside air temperature T5 measured by temperature sensor 25 is used to correct the thermal resistance ratio K. Note that temperature sensor 25 is disposed adjacent to the regions that make up the first region 11 and the second region 12. It is also possible to measure the outside air temperature with one module, and overall, the deep body thermometer 500 can be realized as a small, lightweight, and inexpensive device.

[0024] In this specification, the pair of temperature sensors 21, 22 may be referred to as a "pair of first region temperature sensors 21, 22," and the pair of temperature sensors 23, 24 may be referred to as a "pair of second region temperature sensors 23, 24." The "first region 11" and the "second region 12" are regions in which a "first heat flow path 115" and a "second heat flow path 125," respectively, are provided, which are designed to have a difference between the thermal resistance values ​​R1 and R2 when measuring deep temperatures using the dual heat flow method (see Figures 1(b) and 2, etc.).

[0025] The external connection terminals 28 of the temperature sensors 21, 22, 23, and 24 are connected to the terminals 13c of the substrate 10 via solder 51, thereby establishing an electrical connection between the two and fixing each sensor to the substrate 10.

[0026] The thermal pads 29 of the temperature sensors 23, 24 are connected to the lands 13b of the substrate 10 via solder 51 across the entire overlapping area. This improves thermal coupling with the lands 13b of the substrate 10 (nodes serving as connection points for the second heat flow path 125). The distance between the thermal pads 29 and the lands 13b is fixed by the solder 51, suppressing dynamic distance fluctuations (assuming there is only a gap without the solder 51). During soldering, the thickness of the solder 51 is controlled to fall within a predetermined range of variation, thereby maintaining a substantially constant distance between the thermal pads 29 and the lands 13b. This maintains a substantially constant distance between the pair of second-region temperature sensors 23, 24, enabling the thermal resistance value R2 of the second heat flow path 125 to be maintained substantially constant with good reproducibility even during mass production.

[0027] Next, focusing on the second region 12 of the substrate 10, the second heat flow path 125 is formed by the substrate 10 itself and the "solder 51" interposed between the thermal pad 29 and the land 13b. Because the second heat flow path 125 is formed while making use of the substrate 10 itself, the probe can be constructed with a simple configuration without any special modifications or significant increase in the number of components, resulting in an economically advantageous probe. Through the second heat flow path 125, a second heat flow 120a flows from the back side to the front side of the deep temperature measurement probe 1 (see symbol 120a schematically indicated by a thick arrow in Figure 1(a)).

[0028] (4) Configuration of the First Heat Flow Path 115 Meanwhile, focusing on the first region 11 of the substrate 10, a through-hole 15 is formed in the substrate 10, penetrating between the front surface 10a and the back surface 10b of the substrate 10 directly below the temperature sensors 21, 22 (first region temperature sensors 21, 22). The pair of first region temperature sensors 21, 22 are connected by the through-hole 15. Here, "connected" means not only spatially connected, but also connected in terms of a thermal circuit.

[0029] In the deep temperature measuring probe 1 according to the first embodiment, an air layer 30 is disposed inside the through-hole 15. Reference numeral 15a denotes the inner wall of the through-hole.

[0030] The first heat flow path 115 is formed by the gaps (air layers 30 in the first embodiment) of the through holes 15. In other words, the air layers 30 arranged inside the through holes 15 formed in the substrate 10 realize the thermal resistors that form the first heat flow path 115. A first heat flow 110a flows from the back side to the front side of the deep temperature measurement probe 1 through such a first heat flow path 115 (see symbol 110a schematically indicated by a thick arrow in FIG. 1(a)).

[0031] The first region temperature sensors 21, 22 are configured as semiconductor ICs, and in plan view, the through-hole 15 preferably overlaps with 50% or more of the area of ​​the thermal pad 29 of the IC (or the back surface of the bare chip in Modification 3 described later) (see FIG. 1(b)).More preferably, the through-hole 15 overlaps with the entire area of ​​the thermal pad 29.

[0032] (5) First Heat Flow Measurement System 110 and Second Heat Flow Measurement System 120 The first heat flow path 115 configured in the substrate of the first region 11 and the pair of first region temperature sensors 21, 22 configure the "first heat flow measurement system 110." Similarly, the second heat flow path 125 configured in the substrate of the second region 12 and the pair of second region temperature sensors 23, 24 configure the "second heat flow measurement system 120."

[0033] The deep temperature measurement probe 1 according to the first embodiment can be said to have the following configuration: That is, the probe 1 includes a pair of first region temperature sensors 21, 22 mounted in the first region 11 of the substrate 10 so as to face each other across the substrate 10, and a first heat flow path 115 formed within the substrate in the first region 11, and a "first heat flow measurement system" that measures a first heat flow 110a flowing out from the subject 9. The probe 1 also includes a pair of second region temperature sensors 23, 24 mounted in the second region 12 of the substrate 10 so as to face each other across the substrate 10, and a "second heat flow measurement system 120" that has a second heat flow path 125 formed within the substrate in the second region 12, and measures a second heat flow 120a flowing out from the subject 9. The substrate 10 has a through-hole 15 formed directly below the first region temperature sensors 21, 22, penetrating between the front and back surfaces of the substrate 10, and the first heat flow path 115 is formed by an air layer 30 disposed within the through-hole 15.

[0034] 2. Configuration of the Deep Body Thermometer 500 According to Embodiment 1 Fig. 3 is a block diagram showing an example of the hardware configuration of the deep body thermometer 500 according to Embodiment 1. Reference numeral 200 denotes a temperature measurement unit.

[0035] The deep body temperature meter 500 according to the first embodiment can be configured to include the deep body temperature measurement probe 1 according to the first embodiment described above, and a deep body temperature estimation unit 210 that estimates the deep body temperature TB using the temperatures measured by the pair of first region temperature sensors 21, 22 and the pair of second region temperature sensors 23, 24 of the deep body temperature measurement probe 1. The deep body temperature estimation unit 210 calculates the deep body temperature TB by the dual heat flow method (for example, by calculating Equation (10) described below) to obtain an estimated value.

[0036] The deep temperature estimation unit 210 can be configured as either a dedicated circuit or a general-purpose circuit. As a general-purpose circuit, it can be realized, for example, by an information processing device (no reference numeral) as shown in Fig. 3. The information processing device that constitutes the deep temperature estimation unit 210 has a processor 211, a memory 212, an input / output interface 214, and a communication interface 215. These are connected to a bus BS.

[0037] The processor 211 operates based on programs stored in the storage unit (memory 212 and storage, not shown) and controls each component. The storage unit (unreferenced) also includes a non-volatile storage device (e.g., ROM), which stores a boot program executed by the processor 211 when the information processing device is started, as well as programs dependent on the hardware of the information processing device. The storage, not shown, is composed of auxiliary storage devices such as a solid-state drive (SDD) or a hard disk drive (HDD). The memory 212 appropriately stores data necessary for the processor 211 to execute various controls and processes. The processor 211 calculates and estimates the deep temperature TB by applying temperatures T1 to T4, etc., to equation (10), which will be described later. In this case, the deep temperature estimation unit 210 can also be considered a processor function that calculates and estimates the deep temperature TB.

[0038] The input / output interface 214 performs input / output from / to input / output devices (particularly, temperature sensors 21, 22, 23, 24, and 25 in this example). The communication interface 215 receives data from other electronic devices via a network or the like and sends the data to the processor 211, and also transmits data generated by the processor 211 to other electronic devices via a network or the like.

[0039] 3. Experimental System In equation (10) described below, which is used to estimate the deep temperature TB, it is necessary to identify and prepare the values ​​of the thermal resistance ratio K of the first heat flow measurement system 110 and the second heat flow measurement system 120. If the materials and physical properties of the first heat flow path 115 and the second heat flow path 125 are known, it is possible to theoretically determine the thermal resistance ratio K. However, the inventors have recently developed a method in which a thermal resistance ratio K that is in line with actual conditions is experimentally determined in advance using a separate experimental system, and then the thermal resistance ratio K is applied to equation (10), which will be described in detail below.

[0040] (1) Thermal equivalent circuit of deep area temperature measurement probe 1 Figure 4 is a thermal equivalent circuit diagram of the deep area temperature measurement probe 1 according to embodiment 1. In Figure 4, Ia is the heat flow (value) flowing through the first heat flow path 115, and Ib is the heat flow (value) flowing through the second heat flow path 125. Ic is the heat flow (value) flowing through the thermal resistance Rs (thermal resistance value) between the subject's deep area 9c and the subject's surface 9a (skin) in the first heat flow measurement system 110, and Id is the heat flow (value) flowing through the thermal resistance Rs (thermal resistance value) between the subject's deep area 9c and the subject's surface 9a (skin) in the second heat flow measurement system 120.

[0041] 4, the following equations are established for the first heat flow measurement system 110: Ia=(T1-T3) / R1 (1) Ic=(TB-T1) / Rs (2) Ia=Ic=(T1-T3) / R1=(TB-T1) / Rs (3) From equation (3), TB=T1+(T1-T3)×(Rs / R1) (4) Similarly, the following equations are established for the second heat flow measurement system 120: Ib=(T2-T4) / R2 (5) Id=(TB-T2) / Rs (6) Ib=Id=(T2-T4) / R2=(TB-T2) / Rs (7) From equation (7), TB=T2+(T2-T4)×(Rs / R2) (8)

[0042] There is a method for calculating the deep body temperature TB by removing Rs using equations (4) and (8). However, when the inventors conducted experiments, it was found that it was difficult to accurately calculate the deep body temperature.

[0043] Therefore, the inventors decided to find the deep temperature TB using a different method. First, from the thermal equivalent circuit of Figure 4, the thermal resistance ratio K between the first heat flow measurement system 110 and the second heat flow measurement system 120 is defined as follows: K = [(TB - T2) (T1 - T3)] / [(TB - T1) (T2 - T4)] (9) Then, equation (9) can be transformed into the following equation for finding the deep temperature TB: TB = T1 + (T1 - T2) (T1 - T3) / [K (T2 - T4) - (T1 - T3)] (10) Based on this idea, the inventors conducted preliminary experiments and determined the thermal resistance ratio K using the relationship in equation (9). Then, using the relationship in equation (10), the deep body temperature TB was calculated (estimated) based on the thermal resistance ratio K determined in the preliminary experiment and the temperatures (T1, T2, T3, T4) measured by the temperature sensors (15, 16, 17, 18). Experimental verification confirmed that an accurate deep body temperature could be obtained.

[0044] In other words, it was confirmed that the deep temperature estimation unit 210 of embodiment 1 can be configured to estimate the deep temperature TB by applying the thermal resistance ratio K of the first heat flow path 115 between the pair of first region temperature sensors 21, 22 and the second heat flow path 125 between the pair of second region temperature sensors 23, 24, which is predetermined using the relationship K = [(TB - T2) (T1 - T3)] / [(TB - T1) (T2 - T4)], and the temperatures T1, T2, T3 and T4 measured by probing the subject 9, to the relationship TB = T1 + (T1 - T2) (T1 - T3) / [K (T2 - T4) - (T1 - T3)].

[0045] However, the deep temperature is designated as TB, and the temperatures measured by sensor 21 of the pair of first region temperature sensors arranged on the side of the subject 9, sensor 22 of the pair of second region temperature sensors arranged on the side of the subject 9, sensor 23 of the pair of first region temperature sensors arranged on the side opposite the subject 9, and sensor 24 of the pair of second region temperature sensors arranged on the side opposite the subject 9 are designated as T1, T2, T3, and T4, respectively.

[0046] It should be noted that although formula (2.6) in Non-Patent Document 1 is thought to correspond to formula (10) in this specification, when the inventors checked formula (2.6) in Non-Patent Document 1, there is a possibility that formula (2.6) in Non-Patent Document 1 contains an error.

[0047] (2) Experimental System Configuration Figure 5 is a schematic cross-sectional view of an "experimental system" for experimentally determining the thermal resistance ratio K of the deep temperature measurement probe 1. As shown in Figure 5, a water bath 130 with a large heat capacity is used instead of the deep part 9c of the subject, and this is placed in a thermo-hygrostat (not shown). The temperature (ambient temperature) inside the thermo-hygrostat is set to a predetermined temperature between 10°C and 30°C. The water temperature (deep temperature TB) is maintained at a substantially constant temperature (approximately 37°C). Reference numeral 109 denotes a surrogate subject, whose surface 109a is made of a natural rubber sheet and is a skin substitute simulating living skin. Reference numeral 109b denotes a region corresponding to the middle part of the surrogate subject, and reference numeral 109c denotes a region corresponding to the deep part of the surrogate subject. Reference numeral 131a denotes a support rod supporting a temperature sensor 131 (such as a thermistor). The deep temperature measuring probe 1 is placed on an aluminum tub 133 , and the aluminum tub 133 is floated on the water in the water bath 130 .

[0048] By using such an experimental system, it is possible to obtain (i) the actual deep water temperature (deep temperature TBr) in the water bath 130 by measuring the temperature with the temperature sensor 131. Furthermore, the temperatures sensed by the temperature sensors 21 to 24 of the deep temperature measurement probe 1 are measured by the temperature measurement unit 200 and output to the deep temperature estimation unit 210, and the deep temperature estimation unit 210 performs calculations based on these temperatures, thereby obtaining (ii) an estimated deep water temperature (deep temperature TBp).

[0049] (3) Determination of Thermal Resistance Ratio K Using Equation (9), the thermal resistance ratio K can be determined by conducting an experiment (preliminary experiment) as follows: (a) A preliminary experiment is conducted to measure the actual deep water temperature (deep temperature TBr) and temperatures T1 to T4 using temperature sensors 21 to 24. The thermal resistance ratio K of the deep temperature measurement probe 1 (in a state of thermal equilibrium in the experimental system shown in Figure 5) is calculated by applying the relationship in Equation (9). This process is repeated multiple times. (b) The average thermal resistance ratio K obtained from multiple experiments is calculated. (c) The measured water temperature (deep temperature TBr) is compared with the estimated deep temperature TBp (water temperature) calculated by applying the average thermal resistance ratio K and temperatures T1 to T4 to the relationship in Equation (10), and it is checked whether the difference (error) between the two has become smaller. If the error is large, the above steps (a) to (c) are repeated to determine the thermal resistance ratio K that reduces the error.

[0050] (4) Estimation of deep temperature TB The value of the thermal resistance ratio K determined as described above is stored in memory 212 (see FIG. 3). The temperature is measured using temperature sensors 21 to 24 and temperature measurement unit 200, and deep temperature estimation unit 210 calculates (estimates) deep temperature TB by performing the calculation of equation (10).

[0051] (5) Incorporation of Prior Application The contents of the prior application (Japanese Patent Application No. 2022-53593), which describes the inventions of the inventors of the present application and others (e.g., FIG. 4, paragraphs

[0038] to

[0046] , etc.), can be incorporated into this specification as is and incorporated as is as a method for experimentally determining the thermal resistance ratio K of the present invention. A detailed description of the experimental determination of the thermal resistance ratio K will be omitted hereafter in this specification.

[0052] 4. Effects of the deep temperature measurement probe 1 and deep thermometer 500 according to embodiment 1 (1) The substrate of the deep temperature measurement probe 1 according to embodiment 1 has a through hole 15 formed therein that penetrates between the front and back surfaces of the substrate 10 directly below the first region temperature sensors 21, 22, and the pair of first region temperature sensors 21, 22 are connected by the through hole 15. In other words, in the deep temperature measurement probe 1, the pair of first region temperature sensors 21, 22 are connected by the through hole 15 formed directly below the sensors, and therefore, if no special measures are taken to create a structure consisting only of holes, for example, only an air layer 30 will remain inside the through hole 15, and the thermal resistance value R1 between the pair of first region temperature sensors 21, 22 can be significantly increased. This makes it easier to provide a difference between the thermal resistance value R1 of the first heat flow path 115 (between the pair of first region temperature sensors 21, 22) and the thermal resistance value R2 of the second heat flow path 125 (between the pair of second region temperature sensors 23, 24) even if the substrate 10 constituting the probe is thinned and the thermal resistance value in the thickness direction of the substrate 10 is reduced overall. Therefore, even if the substrate 10 constituting the probe is thinned, it becomes possible to measure the temperature of the deep part 9c of the subject (deep temperature TB) with high accuracy.

[0053] (2) The thermal conductivity of air is 0.0241 W / (mK) (at 0°C), while the thermal conductivity of the material constituting the substrate 10, such as polyimide (PI), is 0.28 to 0.34 W / (mK). In the deep temperature measurement probe 1 according to the first embodiment, an air layer 30 is disposed inside the through-hole 15. Therefore, when considering the deep temperature measurement probe 1 from the perspective of thermal resistance, the air layer 30 can have a thermal resistance value that is orders of magnitude larger than that of the material constituting the substrate 10, etc. Therefore, the thermal resistance value R1 of the first heat flow path 115 constituted by the air layer 30 can be significantly increased, and therefore, a very simple structure can be used to create a difference between the thermal resistance value R1 of the first heat flow path 115 and the thermal resistance value R2 of the second heat flow path 125.

[0054] (3) The deep body thermometer 500 according to the first embodiment includes the deep body temperature measurement probe 1 according to the first embodiment and a deep body temperature estimation unit 210 that estimates a deep body temperature using the temperatures measured by the pair of first region temperature sensors 21, 22 and the pair of second region temperature sensors 23, 24 of the deep body temperature measurement probe 1. The deep body thermometer 500 includes the deep body temperature measurement probe 1 that can measure the temperature of the deep body 9c of the subject (the deep body temperature TB) with high accuracy even on a thin substrate 10, and therefore is a small, highly accurate deep body thermometer.

[0055] (4) The deep thermometer 500 of embodiment 1 is configured to estimate the deep temperature TB by applying the thermal resistance ratio K, which is determined in advance using the relationship expressed by the above equation (9) for calculating the thermal resistance ratio K, and the temperatures T1, T2, T3 and T4 measured by probing the subject 9, to the relationship expressed by the above equation (10).

[0056] In reality, it is thought that the influence of heat flux in a diffusion mode other than linear heat flux is also present, so the thermal resistance ratio K theoretically calculated based on the known thermal conductivity of the materials that make up each heat flow path may differ from the actual accurate thermal resistance ratio K. Therefore, by determining the thermal resistance ratio K in advance using the relationship expressed by the above equation (9) in a separate experimental system, it is possible to estimate the deep temperature TB based on a highly accurate thermal resistance ratio K that is close to that of an actual probe. This makes it possible to measure deep temperature with greater accuracy.

[0057] 6 is a cross-sectional view showing a deep temperature measuring probe 2 according to embodiment 2. The deep temperature measuring probe 2 according to embodiment 2 basically has the same configuration as the deep temperature measuring probe 1 according to embodiment 1, but differs from the deep temperature measuring probe 1 according to embodiment 1 in the way the first heat flow path 115 is configured.

[0058] As shown in FIG. 6 , the deep temperature measurement probe 2 according to the second embodiment further includes a heat insulating paper 31 disposed inside the through-hole 15. The heat insulating paper 31 is paper having a thermal conductivity approximately equal to that of air. For example, the heat insulating paper 31 may be a sheet containing porous particles of silica gel containing foamed air (so-called silica aerogel). When the heat insulating paper 31 is packed into the air layer 30 disposed in the through-hole 15, the overall thermal resistance value R1 of the internal space of the through-hole 15 becomes approximately equal to the thermal resistance value of air. The heat insulating paper 31 may be appropriately formed into a three-dimensional shape by alternately folding it to form a corrugated shape, folding it into a repeating pattern of peaks and valleys, or randomly rolling it, and then packed into the internal space of the through-hole 15.

[0059] By disposing the insulating paper 31 inside the through-hole 15 that constitutes the first heat flow path 115, the insulating paper 31 can prevent the movement of air inside the through-hole 15, thereby suppressing convection inside the through-hole 15. This suppresses the exchange of heat by "convection" inside the first heat flow path 115, and instead the exchange of heat occurs mainly through direct "conduction" via the air layer 30 and the insulating paper 31. This creates an even more ideal state for the thermal circuit, making it possible to measure deep temperatures with even greater accuracy.

[0060] The deep temperature measuring probe 2 according to the second embodiment has a configuration basically similar to that of the deep temperature measuring probe 1 according to the first embodiment, except for the configuration of the first heat flow path 115. Therefore, the deep temperature measuring probe 2 similarly has the corresponding effects of the deep temperature measuring probe 1.

[0061] 7 is a cross-sectional view showing a deep temperature measuring probe 3 according to embodiment 3. The deep temperature measuring probe 3 according to embodiment 3 basically has the same configuration as the deep temperature measuring probe 1 according to embodiment 1, but differs from the deep temperature measuring probe 1 according to embodiment 1 in the configuration of the substrate 10 and the way the first heat flow path 115 is configured.

[0062] As shown in Figure 7, in the deep temperature measurement probe 3 of embodiment 3, the substrate 10 is made of a glass substrate, and the inside of the through hole 15 is configured to be in a vacuum or near-vacuum state 32.

[0063] By making the inside of the through hole 15 that constitutes the first heat flow path 115 a vacuum or near-vacuum state 32, the thermal conductivity can be made even lower than in the case of the air layer 30, that is, the thermal resistance value R1 between the pair of first region temperature sensors 21, 22 can be made even larger.

[0064] The deep temperature measuring probe 3 according to the third embodiment has a configuration basically similar to that of the deep temperature measuring probe 1 according to the first embodiment, except for the configuration of the substrate 10 and the configuration of the first heat flow path 115. Therefore, the deep temperature measuring probe 2 similarly has the corresponding effects of the deep temperature measuring probe 1.

[0065] [Fourth Embodiment] Figure 8 is a diagram illustrating a deep temperature measurement probe 4 according to a fourth embodiment. Figure 8(a) is a cross-sectional view of the deep temperature measurement probe 4, showing the D-D cross section of Figure 8(b). Figure 8(b) is a plan view of the deep temperature measurement probe 4 as viewed along arrow C in Figure 8(a). The deep temperature measurement probe 4 according to the fourth embodiment basically has the same configuration as the deep temperature measurement probes 1, 2, and 3 according to the first, second, and third embodiments, but differs from the deep temperature measurement probes 1, 2, and 3 according to the first, second, and third embodiments in that it is configured to suppress thermal interference between the first heat flow path 115 and the second heat flow path 125.

[0066] As shown in Fig. 8, in the deep temperature measurement probe 4 according to the fourth embodiment, an air layer 40 is disposed between the first region 11 and the second region 12 in the substrate 10. The air layer 40 may be formed by forming a through-hole penetrating between the front surface 10a and the back surface 10b of the substrate 10 as shown in Fig. 8, and by air disposed in the through-hole. The through-hole may be configured as an elongated hole that penetrates most of the lateral region of the temperature sensor as shown in Fig. 8.

[0067] Because the deep temperature measurement probe 4 according to the fourth embodiment has this configuration, the air layer 40, which can be considered a heat insulator, can block heat conduction between the first region 11 in which the first heat flow path 115 is arranged and the second region 12 in which the second heat flow path 125 is arranged. This reduces thermal interference between the first heat flow path 115 and the second heat flow path 125 and increases the independence of the two heat flow paths, enabling deep temperature measurement with even higher accuracy.

[0068] The deep temperature measurement probe 4 according to the fourth embodiment has a configuration that is basically the same as the deep temperature measurement probes 1, 2, and 3 according to the first, second, and third embodiments, except that it is configured to suppress thermal interference between the first heat flow path 115 and the second heat flow path 125. Therefore, the deep temperature measurement probe 4 similarly has the corresponding effects of the deep temperature measurement probes 1, 2, and 3.

[0069] Although the present invention has been described above based on the above embodiment, the present invention is not limited to the above embodiment and can be embodied in various forms without departing from the spirit of the present invention, and for example, the following modifications are also possible.

[0070] (1) In each embodiment, the second heat flow path 125 is configured using the substrate 10 itself. However, the present invention is not limited to this. For example, as shown in FIG. 9 , another through-hole 17 may be formed in the substrate 10 directly below the second region temperature sensors 23, 24, penetrating between the front surface 10 a and the back surface 10 b of the substrate 10, and a metal 37 may be embedded in the another through-hole 17, so that the pair of second region temperature sensors 23, 24 are connected via the metal 37 (Variation 1). Note that FIG. 9 is a cross-sectional view showing a deep temperature measurement probe 5 according to Variation 1.

[0071] Copper, for example, can be used as the metal 37. The thermal conductivity of copper is 403 [W / (mK)] (at 0 [°C]), which is orders of magnitude greater than that of the materials constituting the substrate 10 and the like. From the perspective of thermal resistance, the metal 37 can have a thermal resistance value that is orders of magnitude smaller than that of the materials constituting the substrate 10 and the like. Therefore, the thermal resistance value R2 of the second heat flow path 125 formed by the metal 37 can be significantly reduced, and the difference from the thermal resistance value R1 of the first heat flow path 115 can be easily ensured.

[0072] (2) In each embodiment, the thermal pads 29 of the temperature sensors 23, 24 and the lands 13b of the wiring pattern 13 are connected by solder 51. However, the present invention is not limited to this. For example, a structure without electrical connection may be used in which there is only a gap (air layer) between the thermal pads 29 and the lands 13b of the wiring pattern 13 without the "solder 51" interposed therebetween (not shown). Even with this structure, thermal coupling between the pair of second region temperature sensors 23, 24 is still possible.

[0073] (3) In each embodiment, the temperature sensors 21 to 24 are described as being implemented using ICs in a SON package. However, the present invention is not limited to this. For example, as shown in FIG. 10( a), the temperature sensors 21 to 24 can be configured as ICs in a WL-CSP (Wafer Level Chip Size Package) (Variation 2). Also, as shown in FIG. 10( b), the temperature sensors 21 to 24 can be configured as bare chips directly mounted on the substrate 10 (Variation 3). Although not shown, the temperature sensors may be configured as temperature sensors other than ICs, such as thermocouples.

[0074] (4) In the deep temperature measurement probe 4 according to the fourth embodiment, an example (see FIG. 8 ) has been described in which "slot-shaped (in plan view)" through-holes are formed penetrating between the front surface 10a and the back surface 10b of the substrate 10 to thermally separate the first region 11 and the second region 12. However, the present invention is not limited to this. For example, as shown in FIGS. 11( a) and 11(b), a configuration can be adopted in which multiple spot-like through-holes are arranged in parallel, each having a "perfect circular (in plan view)" shape rather than a "slot" shape, penetrating the substrate 10 (Modification 4). Furthermore, as shown in FIGS. 11(c) and 11(d), a cavity can be formed inside the substrate 10 in the thickness direction, and an air layer 40 can be formed by disposing air in the cavity (Modification 5).

[0075] 11, an air layer 41 may also be provided between the area constituting the first area 11 and the second area 12 and the temperature sensor 25. The air layer 41 may be configured as an elongated hole that penetrates most of the area to the side of the temperature sensor 25 as shown in the figure.

[0076] When viewed from the second region 12, in a plan view of the drawing, the air layer 40 is located on the left side, the air layer 41 is located on the right side, and the atmosphere 8 (air layer) is located above and below. Similarly, when viewed from the first region 11, in a plan view of the drawing, the air layer 40 is located on the right side, and the atmosphere 8 (air layer) is located on the left side, above, and below. In other words, an air layer is located around the first region 11 and / or the second region 12. With the above-described configuration, the heat flux between the pair of temperature sensors arranged on the front and back of the substrate 10 is covered / surrounded by an air layer with low thermal conductivity, so the heat flow cannot flow horizontally in a plan view, resulting in an ideal heat flux only in the vertical direction, further improving the accuracy of the deep temperature that can be measured. Furthermore, by forming a long hole so that it covers / surrounds the area around the temperature sensor as seamlessly as possible (on all four sides if possible), the heat flux will be even more ideal and only in the vertical direction, further improving the accuracy of the deep temperature that can be measured. Furthermore, heat insulating paper 31 having a thermal conductivity approximately equal to that of air may be disposed in each of the air layers 40 and 41 .

[0077] FIG. 10 is a cross-sectional view of the main parts of the deep temperature measurement probes 6 and 7 according to Modifications 2 and 3. FIG. 11 is a view shown to explain the deep temperature measurement probes 4' and 4'' according to Modifications 4 and 5. FIG. 11(a) is a plan view of the deep temperature measurement probe 4', and FIG. 11(b) is a cross-sectional view of the deep temperature measurement probe 4' showing the E-E cross section of FIG. 11(a). FIG. 11(c) is a plan view of the deep temperature measurement probe 4'' and FIG. 11(d) is a cross-sectional view of the deep temperature measurement probe 4'' showing the F-F cross section of FIG. 11(c).

[0078] 1, 2, 3, 4, 4', 4'', 5, 6, 7...Deep temperature measurement probe, 8...atmosphere, 9...object, 9a...object surface, 9b...object intermediate portion, 9c...object deep portion, 10...substrate, 10a...surface (of substrate), 10b...back surface (of substrate), 11...first region, 12...second region, 13...(broad) wiring pattern, 13a...(narrow) wiring pattern, 13b...land, 13c...terminal, 15...through hole, 17...another through hole, 21, 22...first region temperature sensor, 23, 24...second region temperature sensor, 25...temperature sensor, 28...external connection terminal, 29...thermal pad, 30...air layer, 31...insulating paper, 32...vacuum or near-vacuum state, 37...metal, 40, 41...air layer, 51...solder, 109a...surface of surrogate specimen, 110...first heat flow measurement system, 110a...first heat flow, 115...first heat flow path, 120...second heat flow measurement system, 120a...second heat flow, 125...second heat flow path, 130...water bath, 131...temperature sensor, 133...aluminum tub, 200...temperature measurement unit, 210...core temperature estimation unit, 211...processor, 212...memory, 214...input / output interface, 215...communication interface, 500...core thermometer

Claims

1. A deep temperature measuring probe used for measuring the temperature of a deep part of a subject, A substrate; A pair of temperature sensors, which are mounted in the first region of the substrate so as to face each other across the substrate, are called "a pair of first region temperature sensors"; A pair of temperature sensors, which are mounted in the second region of the substrate so as to face each other across the substrate, are called "a pair of second region temperature sensors"; Equipped with a through hole is formed in the substrate directly below the first region temperature sensor, the through hole passing through the substrate from the front surface to the back surface, and the pair of first region temperature sensors are connected by the through hole; A probe for measuring deep body temperature.

2. The deep temperature measuring probe according to claim 1, An air layer is disposed inside the through hole. A probe for measuring deep body temperature.

3. The deep temperature measuring probe according to claim 2, Further, a heat insulating paper is arranged inside the through hole. A probe for measuring deep body temperature.

4. The deep temperature measuring probe according to claim 1, The substrate is a glass substrate, The inside of the through hole is in a vacuum or near-vacuum state. A probe for measuring deep body temperature.

5. The deep temperature measuring probe according to claim 1, a through hole is formed in the substrate, penetrating between the front surface and the back surface of the substrate directly below the second region temperature sensor, and a metal is embedded in the through hole, and the pair of second region temperature sensors are connected via the metal; A probe for measuring deep body temperature.

6. The deep temperature measuring probe according to any one of claims 1 to 5, In the substrate, an air layer is disposed between the first region and the second region. A probe for measuring deep body temperature.

7. The deep temperature measuring probe according to any one of claims 1 to 5, In the substrate, an air layer is disposed around the first region and / or the second region. A probe for measuring deep body temperature.

8. The deep temperature measuring probe according to any one of claims 1 to 5, A temperature sensor for measuring an outside air temperature is disposed on the substrate so as to be adjacent to an area constituting the first area and the second area. A probe for measuring deep body temperature.

9. A deep temperature measuring probe used for measuring the temperature of a deep part of a subject, A plate-shaped substrate; a pair of first region temperature sensors which are a pair of temperature sensors mounted in a first region of the substrate so as to face each other across the substrate, and a first heat flow measurement system which has a first heat flow path formed in the substrate in the first region and measures a first heat flow flowing out from the specimen; a pair of second region temperature sensors which are a pair of temperature sensors mounted in the second region of the substrate so as to face each other across the substrate, and a second heat flow measurement system which has a second heat flow path formed in the substrate in the second region and measures a second heat flow flowing out from the specimen, a through hole penetrating between the front surface and the back surface of the substrate directly below the first region temperature sensor is formed in the substrate, and the first heat flow path is constituted by an air layer disposed inside the through hole; A probe for measuring deep body temperature.

10. The deep temperature measuring probe according to claim 9, Further, a heat insulating paper is arranged inside the through hole. A probe for measuring deep body temperature.

11. A probe for measuring deep temperature according to any one of claims 1 to 5, A deep temperature estimator comprising: a deep temperature estimation unit that estimates deep temperatures using the temperatures measured by the pair of first area temperature sensors and the pair of second area temperature sensors of the deep temperature measurement probe.

12. The deep body thermometer according to claim 11, When the deep temperature is TB, and the temperatures measured by the sensor of the pair of first region temperature sensors arranged on the subject side, the sensor of the pair of second region temperature sensors arranged on the subject side, the sensor of the pair of first region temperature sensors arranged on the opposite side to the subject, and the sensor of the pair of second region temperature sensors arranged on the opposite side to the subject are T1, T2, T3, and T4, respectively, The deep body temperature estimation unit is a thermal resistance ratio K of a first heat flow path between the pair of first region temperature sensors and a second heat flow path between the pair of second region sensors, the thermal resistance ratio K being determined in advance using a relationship of K=[(TB-T2)(T1-T3)] / [(TB-T1)(T2-T4)]; and the temperatures T1, T2, T3 and T4 measured by probing the specimen, TB=T1+(T1-T2)(T1-T3) / [K(T2-T4)-(T1-T3)] A deep body thermometer characterized in that the deep body temperature TB is estimated by applying the relationship:

13. A probe for measuring deep temperature according to claim 9 or 10, A deep temperature estimator comprising: a deep temperature estimation unit that estimates deep temperatures using the temperatures measured by the pair of first area temperature sensors and the pair of second area temperature sensors of the deep temperature measurement probe.

14. The deep thermometer according to claim 13, When the deep temperature is TB, and the temperatures measured by the sensor of the pair of first region temperature sensors arranged on the subject side, the sensor of the pair of second region temperature sensors arranged on the subject side, the sensor of the pair of first region temperature sensors arranged on the opposite side to the subject, and the sensor of the pair of second region temperature sensors arranged on the opposite side to the subject are T1, T2, T3, and T4, respectively, The deep body temperature estimation unit is a thermal resistance ratio K of a first heat flow path between the pair of first region temperature sensors and a second heat flow path between the pair of second region sensors, the thermal resistance ratio K being determined in advance using a relationship of K=[(TB-T2)(T1-T3)] / [(TB-T1)(T2-T4)]; and the temperatures T1, T2, T3 and T4 measured by probing the specimen, TB=T1+(T1-T2)(T1-T3) / [K(T2-T4)-(T1-T3)] A deep body thermometer characterized in that the deep body temperature TB is estimated by applying the relationship: