Measurement device

Abstract

According to one embodiment of the present invention, there is provided a measurement device comprising a substrate to which heat from a measurement object is conducted, and at least one thermoelectric conversion part, the substrate being provided with a placement surface, the thermoelectric conversion part being provided on the substrate so as to generate a heat flow due to the heat transferred via the placement surface, and being configured so as to output a first signal and a second signal, the first signal including a first thermoelectromotive force generated by the heat flow and a first noise signal based on a disturbance applied to the thermoelectric conversion part, the second signal including a second thermoelectromotive force generated by the heat flow and a second noise signal based on the disturbance, the first thermoelectromotive force and the second thermoelectromotive force being output with inverted signs with respect to the same heat flow, and the first noise signal and the second noise signal being generated with the same sign with respect to the same disturbance regardless of the direction of the heat flow flowing through the thermoelectric conversion part.

Description

Measurement device

[0001] The present invention relates to a measurement device.

[0002] Patent Document 1 discloses a technique related to a thermoelectric conversion device that can generate a voltage due to a temperature difference and can suppress a leakage magnetic field much more than conventionally.

[0003] The thermoelectric conversion device includes a thermoelectric conversion element made of an antiferromagnet having a non-collinear spin structure, and by flowing a heat current in a direction orthogonal to the in-plane minute magnetization direction with respect to the thermoelectric conversion element to give a temperature difference, a voltage can be generated in a direction orthogonal to the minute magnetization direction and the heat current direction respectively by the anomalous Nernst effect. Further, in the thermoelectric conversion device, since the thermoelectric conversion element is formed of an antiferromagnet having no strong magnetization like a ferromagnet, the generation of a leakage magnetic field can be significantly suppressed as compared with a conventional thermoelectric conversion device using a ferromagnet.

[0004] Japanese Patent Application Laid-Open No. 2017-084854

[0005] By the way, when measuring the heat flow near a device where a large current such as a motor may flow or a path for supplying power to the device using a measurement system including such a thermoelectric conversion element, electromagnetic noise such as hum noise due to the current may be applied to the measurement system.

[0006] According to one aspect of the present invention, there is provided a measurement device including a substrate to which heat from a measurement object is conducted and at least one thermoelectric conversion unit, the substrate having a mounting surface, the thermoelectric conversion unit being provided on the substrate so as to generate a heat current due to heat transmitted through the mounting surface, and configured to output a first signal and a second signal, the first signal including a first thermoelectromotive force generated by the heat current and a first noise signal based on a disturbance applied to the thermoelectric conversion unit, the second signal including a second thermoelectromotive force generated by the heat current and a second noise signal based on the disturbance, the first thermoelectromotive force and the second thermoelectromotive force being output with inverted signs for the same heat current, and the first noise signal and the second noise signal being configured to be generated with the same sign for the same disturbance regardless of the direction of the heat current flowing through the thermoelectric conversion unit.

[0007] This configuration makes it possible to provide a measuring device that can easily reduce noise signals with respect to the thermoelectric power component.

[0008] This figure shows an example of the configuration of a measuring device. This figure shows a first embodiment of the element section shown in Figure 1. This figure shows another example of the element section shown in Figure 2. This figure shows a second embodiment of the element section shown in Figure 1. This figure shows another example of the element section shown in Figure 4. This figure shows a third embodiment of the element section shown in Figure 1.

[0009] Embodiments of the present invention will be described below with reference to the drawings. The various features shown in the embodiments below are interchangeable. In this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations are omitted.

[0010] Incidentally, the program for realizing the software appearing in one embodiment may be provided as a computer-readable non-transitor-readable medium, or it may be provided so that it can be downloaded from an external server, or it may be provided so that the program is launched on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0011] Furthermore, in various information processing according to one embodiment, an input and an output corresponding to the input can be realized. Here, as long as an output is obtained as a result of the input, the form of the information referenced in such information processing (hereinafter referred to as "reference information") is not limited. The reference information may be, for example, rule-based information such as a database, a lookup table, or a predetermined function (including a decision formula such as a regression equation constructed by a statistical method), or a pre-trained model that has learned the correlation between input and output in advance, or a generative AI such as a large-scale language model or visual language model that can output a desired result by inputting a prompt.

[0012] Furthermore, in one embodiment, "part" may include, for example, hardware resources implemented by a circuit in a broad sense, and the information processing of software that can be specifically realized by these hardware resources. Also, in one embodiment, various types of information are handled, and this information can be represented, for example, by the physical values ​​of signal values ​​representing voltage and current, the high or low values ​​of signal values ​​as a set of binary bits composed of 0s or 1s, or by quantum superposition (so-called qubits), and communication and calculations can be performed on a circuit in a broad sense.

[0013] Furthermore, a circuit in a broad sense is a circuit realized by combining at least an appropriate combination of circuits, circuits, processors, and memory. The processor may be a general-purpose processor or a dedicated circuit. In other words, this includes application-specific integrated circuits (ASICs), programmable logic devices (for example, simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)), etc.

[0014] Furthermore, the thermoelectric conversion section described below is preferably a thin-film type thermoelectric conversion device based on the anomalous Nernst effect, from the viewpoint of responsiveness. The elements of the thermoelectric conversion device (thermoelectric elements) may be composed of alloys or compounds that exhibit the anomalous Nernst effect. These elements may be composed of, for example, topological ferromagnetic materials or topological antiferromagnetic materials called Weyl semimetals, or ferrimagnetic materials, or combinations thereof. The topological ferromagnetic material is Co ２ Co such as MnGa ２ The TX composition may be a metal (where X is one of Si, Ge, Sn, Al, and Ga), or the composition formula may be Fe３ X may be a known alloy of a topological ferromagnetic material, such as a metal represented by X (where X is a stoichiometric composition of a typical element or transition element such as Al or Ga). Furthermore, the topological antiferromagnetic material may be Mn. ３ X (where X is one or more elements selected from Sn, Ge, Ga, Pt, Ir, Rh, or compounds thereof) may be a known topological antiferromagnetic material. The compound constituting the element may be, for example, an alloy having a transition metal, and the alloy may be a compound having a crystal structure with a kagome lattice plane due to the transition metal, and may exhibit an anomalous Nernst effect. The ferrimagnetic material is also not particularly limited as long as it exhibits an anomalous Nernst effect. The structure of the element is not particularly limited, and known structures can be used. Furthermore, the element according to this embodiment may be provided by sputtering, vapor deposition, MBE, plating, granulation, 3D printing, melting, sintering, printing, bonding, etc. Since the thin-film type thermoelectric conversion section based on the anomalous Nernst effect is an alloy, its thermal resistance and heat capacity are lower than those of a thermoelectric conversion section that exhibits the Seebeck effect. Therefore, its sensitivity is higher than that of a conventional Seebeck effect thermoelectric conversion section, and its time response is excellent. The thickness of the element of the thermoelectric conversion section is not particularly limited, but it is preferably less than 1 micrometer. The thermoelectric conversion unit may be a thermoelectric conversion unit that exhibits the Seebeck effect described above. To improve thermal responsiveness, for example, the thickness of the Seebeck effect element is preferably less than 250 micrometers, more preferably less than 100 micrometers, even more preferably less than 10 micrometers, and even more preferably less than 1 micrometer.

[0015] 1. Overview of the Measurement Device First, an overview of the measurement device will be described. Figure 1 is a diagram showing an example of the configuration of the measurement device. As shown in Figure 1, the measurement device 1 is configured to output a thermoelectric voltage corresponding to the heat flow J generated by heat exchange with the object to be measured 100. The thermoelectric voltage output from the measurement device 1 can be used for various purposes through various signal processing, such as managing various states of the object to be measured 100, such as its temperature, and controlling the operation of the object to be measured 100. In this embodiment, the measurement device 1 is a thin device having thickness along the z direction Dz. Hereinafter, for the sake of convenience, the two in-plane directions perpendicular to the z direction Dz will be referred to as the x direction Dx and the y direction Dy. Each direction Dx, Dy, and Dz is defined to be orthogonal to each other. The measurement device 1 comprises a substrate 2 and an element section 3.

[0016] The substrate 2 is positioned so that heat from the object to be measured 100 is conducted to it. The substrate 2 is formed, for example, in the shape of a flat plate and has a mounting surface 21 and an opposite surface 22. The mounting surface 21 and the opposite surface 22 are planes extending in the x-direction Dx and y-direction Dy, respectively, as in-plane directions. The opposite surface 22 is located opposite the mounting surface 21 in the thickness direction of the substrate 2. The thickness direction of the substrate 2 is assumed to be along the z-direction Dz.

[0017] The element unit 3 is provided on the substrate 2 such that a heat flow J is generated by heat transmitted through the mounting surface 21. The element unit 3 includes at least one thermoelectric conversion unit 4. The thermoelectric conversion unit 4 is configured to generate a thermoelectric voltage based on the heat flow J. The heat flow J flows, for example, in a direction along the thickness direction of the substrate 2. The element unit 3 is configured to output signals indicating various values ​​and states of the measurement target 100, such as heat generation, temperature, and driving mode, by performing various signal processing on the thermoelectric voltage. In this embodiment, the element unit 3 is stacked in layers on the mounting surface 21. The measurement target 100 can be various objects such as semiconductor elements (especially power semiconductor elements), motors, and power converters.

[0018] For example, the thermoelectric conversion unit 4 is configured to output a first signal and a second signal. The first signal includes a first thermoelectric voltage generated by the heat flow J and a first noise signal based on disturbances applied to the thermoelectric conversion unit. The second signal includes a second thermoelectric voltage generated by the heat flow J and a second noise signal based on disturbances. The first and second thermoelectric voltages are output with inverted signs for the same heat flow J. The first and second noise signals are configured to be generated with the same sign for the same disturbance, regardless of the direction of the heat flow J flowing through the thermoelectric conversion unit. With such a configuration, by taking the difference between the first and second signals, a measuring device 1 can be provided that can easily reduce the noise signal with respect to the thermoelectric voltage component. Note that the element unit 3 and the thermoelectric conversion unit 4 are not limited to having such a configuration. Details of the element unit 3 and the thermoelectric conversion unit 4 will be explained exemplified in the following sections.

[0019] The measuring device 1 may further include a housing B. The housing B is configured to house the substrate 2 and the element unit 3. The housing B may be made of a conductive material such as metal. This allows the housing B to function as a conductive shield, thereby suppressing external electromagnetic disturbances from affecting the element unit 3.

[0020] The housing B is connected to the substrate 2 and the element portion 3 via electrically insulating adhesive layers Gr1 and Gr2. For example, the housing B includes a substrate support portion B1 and an upper portion B2.

[0021] The substrate support portion B1 is directly connected to the opposite surface 22. With this configuration, electromagnetic disturbances that may be applied to the thermoelectric conversion portion 4 can be reduced while suppressing an unintentional increase in the size of the measuring device 1. Note that the direct connection between the substrate support portion B1 and the opposite surface 22 is not limited to the connection between the substrate support portion B1 and the opposite surface 22 without any intermediaries, and may include any connection method that does not involve the element portion 3. For example, the direct connection between the substrate support portion B1 and the opposite surface 22 may include connection via various functional layers such as an insulating layer or an adhesive layer. The substrate support portion B1 is formed from a flat plate-shaped member such as a metal plate and is pressed against the opposite surface 22 via an adhesive layer Gr1.

[0022] The upper surface portion B2 is positioned opposite the substrate support portion B1 in the z-direction Dz, and together with the substrate support portion B1, it sandwiches the substrate 2 and the element portion 3 in the z-direction Dz. At this time, the upper surface portion B2 is connected to the element portion 3 via the adhesive layer Gr2. The adhesive layer Gr2 electrically insulates the upper surface portion B2 and the element portion 3 from each other. In this way, the housing B covers the substrate 2 and the element portion 3 (and furthermore, the thermoelectric conversion portion 4 provided in the element portion 3) by sandwiching them between the substrate support portion B1 and the upper surface portion B2. As a result, the housing B can protect the substrate 2 and the element portion 3 from external forces while suppressing the generation of noise due to electromagnetic disturbances. In other words, the measuring device 1 may further include adhesive layers Gr1 and Gr2, which are examples of insulating layers, and the housing B as a conductive shield. The conductive shield has electrical conductivity and covers the thermoelectric conversion portion so as to sandwich the substrate 2 and the thermoelectric conversion portion 4 via the insulating layer. This configuration makes it possible to reduce electromagnetic disturbances such as hum noise that may be applied to the thermoelectric conversion unit 4. The shapes of the substrate support portion B1 and the upper surface portion B2 are formed, for example, in a flat plate shape. The housing B may also have a peripheral wall portion that connects the outer edge of the substrate support portion B1 and the outer edge of the upper surface portion B2. This allows the housing B to cover almost the entire substrate 2 and element portion 3, thereby further reducing noise. In this case, the housing B may have connection ports that can be connected to wiring extending from the substrate 2 or element portion 3.

[0023] 2. Example Configuration of Element Unit 3 Next, an example configuration of the element unit 3 described above will be explained.

[0024] 2.1. First Embodiment of Element Unit 3 First, the element unit 3a will be described as the element unit 3 according to the first embodiment. Figure 2 is a diagram showing the first embodiment of the element unit shown in Figure 1.

[0025] As shown in Figure 2, the element unit 3a comprises one thermoelectric conversion unit 4 and a signal processing unit 5.

[0026] The thermoelectric conversion unit 4 is configured to output a signal based on the thermoelectric voltage generated by the heat flow J. The thermoelectric conversion unit 4, configured to generate the thermoelectric conversion unit, comprises at least one (for example, five) thermoelectric conversion elements 41, wiring 42, a first terminal 43, a second terminal 44, and a reference terminal 45.

[0027] The thermoelectric element 41 generates a thermoelectric voltage based on the heat flow J. Here, the thermoelectric voltage is induced along a direction perpendicular to the heat flow J (in this embodiment, the y-direction Dy). The polarity of the thermoelectric voltage with respect to the direction of the heat flow J (i.e., the direction of the voltage gradient) is determined according to the polarity of the thermoelectric element 41. If the thermoelectric voltage is due to an abnormal Nernst effect, the polarity of the thermoelectric element 41 is determined according to the direction of the spontaneous magnetization M of the thermoelectric element 41. In this embodiment, the polarity of the thermoelectric elements 41 provided in one thermoelectric conversion unit 4 is predetermined. In this embodiment, the thermoelectric element 41 is a thin-film element formed in a rectangular shape with a width in the x-direction and extending in the y-direction, and is laminated on the mounting surface 21 of the substrate 2 by, for example, sputtering or epitaxial growth.

[0028] The wiring 42 is configured to reinforce the thermoelectric voltage by connecting the thermoelectric elements 41 in series with each other. Here, since the thermoelectric elements 41 have the same polarity, they are arranged to form meander wiring such that the thermoelectric elements 41 and the wiring 42 are alternately aligned in the x-direction Dx.

[0029] The first terminal 43 and the second terminal 44 are connected to a series connection of thermoelectric elements so as to output thermoelectric power to the outside. Here, the potential difference between the first terminal 43 and the second terminal 44 is the sum of the thermoelectric powers output from each of the thermoelectric elements 41.

[0030] The reference terminal 45 is connected between the first terminal 43 and the second terminal 44 on the circuit defined by the series connection of the thermoelectric conversion elements 41. For example, the reference terminal 45 is connected such that the difference between the resistance between the first terminal 43 and the reference terminal 45 and the resistance between the second terminal 44 and the reference terminal 45 is less than or equal to a specified allowable value. The allowable value can be appropriately determined according to the noise that is allowed to be superimposed on the thermoelectric voltage. Ideally, the reference terminal 45 is located at the midpoint of the resistance between the first terminal 43 and the second terminal 44 so that the resistance between the first terminal 43 and the reference terminal 45 is equal to the resistance between the second terminal 44 and the reference terminal 45. In this embodiment, since an odd number (five) of thermoelectric elements 41 are connected in series between the first terminal 43 and the second terminal 44, a reference terminal 45 is provided on the central thermoelectric element 41a (in this case, the third from each of the first and second terminals 44) of the series connection of the five thermoelectric elements 41. The position of the reference terminal 45 on the thermoelectric element 41a is arbitrary, but for example, it is provided near the midpoint of both ends of the thermoelectric element 41a in the x-direction Dx. This makes it possible to reduce the difference between the resistance value between the first terminal 43 and the reference terminal 45 and the resistance value between the second terminal 44 and the reference terminal 45 when each thermoelectric element 41 has a similar resistance distribution. The reference terminal 45 is also called a common terminal. Note that these terminals 43 to 45 are not limited to physical terminals such as connection ports, but may also be virtual terminals such as wiring 42 located at the boundary of the thermoelectric conversion section 4 which is conveniently divided. The reference terminal 45 can be connected to a ground that indicates a reference potential. The object that serves as the ground can be arbitrary, but for example, it is preferable that the reference terminal 45 is connected to the housing B described above.

[0031] The thermoelectric conversion unit 4 according to this embodiment can output a voltage V1 generated between the first terminal 43 and the reference terminal 45 as a first signal, and a voltage V2 generated between the second terminal 44 and the reference terminal 45 as a second signal. With such a configuration, a measuring device 1 can be provided that can easily reduce noise signals with respect to the thermoelectric power component with a simple configuration. Here, voltages V1 and V2 are the potential differences between the respective terminals 43 and 44 with respect to the reference terminal 45, and may include the thermoelectric power originating from the thermoelectric conversion element 41 and noise signals that are generated independently of the thermoelectric power. Comparing voltages V1 and V2, the thermoelectric power is inverted for the same heat flow J, whereas the noise signal is generated with the same sign for the same disturbance regardless of the direction of the heat flow J (i.e., without dependence on the direction of the path).

[0032] The signal processing unit 5 is configured to acquire a first signal (e.g., voltage V1) and a second signal (e.g., voltage V2) output from the thermoelectric conversion unit 4, and to output the difference between the acquired first signal and the second signal. The specific manner in which the difference is output is arbitrary, but it is provided with three input terminals 51 to 53 and one output terminal 54. Input terminal 51 is connected to the first terminal 43. Input terminal 52 is connected to the second terminal 44. Input terminal 53 is connected to the reference terminal 45. Input terminal 53 is a terminal for defining the reference potential for voltages V1 and V2, and can be implemented in any manner as long as voltages V1 and V2 can be defined. Output terminal 54 outputs the difference between voltages V1 and V2 input from input terminals 51 to 53 as the output signal V ｏｕｔ This is a terminal for outputting data.

[0033] The specific configuration of the signal processing unit 5 may be an analog circuit or a digital circuit. In the case of an analog circuit, for example, the signal processing unit 5 may be a differential amplifier or an instrument amplifier. Also, the signal processing circuit may have a voltage follower interposed between the differential amplifier or instrument amplifier and the input terminals 51 and 52. This results in the output signal V ｏｕｔ This can make it more stable.

[0034] In the above embodiment, the reference terminal 45 was connected to the thermoelectric conversion element 41a, but this is not the only example. Figure 3 shows another example of the element section shown in Figure 2. As shown in Figure 3, for example, the reference terminal 45 may be connected to the wiring 42 between the thermoelectric conversion elements 41. In particular, if the thermoelectric conversion section 4 comprises a series connection of thermoelectric conversion elements 41 having the same resistance distribution, the reference terminal 45 may be connected to a position in the wiring 42 where the number of thermoelectric conversion elements 41 between the first terminal 43 and the reference terminal 45 is equal to the number of thermoelectric conversion elements 41 between the second terminal 44 and the reference terminal 45.

[0035] 2.2. First Embodiment of Element Unit 3 Next, we will describe element unit 3b as an element unit 3 according to the second embodiment. Figure 4 is a diagram showing the second embodiment of the element unit shown in Figure 1. Here, we will mainly describe the elements of the second embodiment that differ from those of the first embodiment, and the explanation of components common to the first embodiment will be omitted by assigning the same number.

[0036] As shown in Figure 4, the element section 3b includes at least one thermoelectric conversion section 4, which consists of a first thermoelectric conversion section 4a and a second thermoelectric conversion section 4b. Each of the thermoelectric conversion sections 4a and 4b is equipped with a plurality of thermoelectric conversion elements 41, wiring 42, a first terminal 43, and a second terminal 44, similar to the thermoelectric conversion section 4 described in the previous section. In the example shown in Figure 4, unlike the thermoelectric conversion section 4 shown in Figure 2, the thermoelectric conversion sections 4a and 4b do not have a reference terminal 45, but the thermoelectric conversion sections 4a and 4b may also be equipped with a reference terminal. In other words, each of the first thermoelectric conversion section 4a and the second thermoelectric conversion section 4b may be equipped with at least one thermoelectric conversion element 41. Each of the thermoelectric elements 41 of the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b generates a thermoelectric voltage based on the heat flow J, and is configured to reinforce the thermoelectric voltage by being connected in series with each other in the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b. The thermoelectric elements 41 of the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b are defined to extend along a first in-plane direction along the mounting surface 21. In this embodiment, the thermoelectric elements 41 of the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b extend linearly in the y-direction Dy along the mounting surface 21. In order to align the reference potential of the voltages V3 and V4, the second terminals 44 of each of the thermoelectric conversion units 4a and 4b may be connected to a common ground. This ground is, for example, the housing B.

[0037] The first thermoelectric conversion unit 4a outputs a voltage V3 as the first signal. Voltage V3 is the potential difference (voltage) at the first terminal 43 with respect to the second terminal 44 in the first thermoelectric conversion unit 4a. The second thermoelectric conversion unit 4b outputs a voltage V4 as the second signal. Voltages V3 and V4, like voltages V1 and V2, may include components derived from the thermoelectric power and noise signals. Here, the second thermoelectric conversion unit 4b is arranged so that a heat flow J flows in the same direction as the heat flow J flowing through the first thermoelectric conversion unit 4a, and is configured so that the sign of the second thermoelectric power is opposite to that of the first thermoelectric power based on the heat flow J. With such a configuration, a measuring device 1 can be provided that can reduce the noise signal with respect to the thermoelectric power component by taking the difference between voltage V3 and voltage V4.

[0038] The configuration to reverse the sign of the thermoelectric power is arbitrary, but for example, the sign of the thermoelectric power may be reversed by reversing the polarity of the thermoelectric conversion element 41 in the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b. Specifically, for example, the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b are defined as having similar circuit configurations on the mounting surface 21 of the same substrate 2, and are configured such that the direction of the spontaneous magnetization Ma of the thermoelectric conversion element 41 of the first thermoelectric conversion unit 4a and the direction of the spontaneous magnetization Mb of the thermoelectric conversion element 41 of the second thermoelectric conversion unit 4b are antiparallel to each other.

[0039] In this embodiment, the signal processing unit 5 is provided with two pairs of input terminals 51a, 51b, 52a, and 52b for receiving the input of the two voltages V3 and V4. The terminals 43 and 44 of the first thermoelectric conversion unit 4a are connected to the input terminals 51a and 52a, respectively. The terminals 43 and 44 of the second thermoelectric conversion unit 4b are connected to the input terminals 51b and 52b, respectively. If the second terminal 44 of the second thermoelectric conversion unit 4b takes on a common potential (for example, by being connected to ground), the input terminals 52a and 52b may be shared.

[0040] The voltage V3 output from the first thermoelectric conversion unit 4a is input to the input terminals 51a and 51b of the signal processing unit 5, and the voltage V4 output from the second thermoelectric conversion unit 4b is input to the input terminals 52a and 52b of the signal processing unit 5. Of the components derived from thermoelectric power and noise signals contained in voltages V3 and V4, the components derived from thermoelectric power are inverted from each other, and the noise signals are superimposed in almost the same way regardless of the direction of the heat flow J. Therefore, by taking the difference between voltages V3 and V4, it is possible to reduce the noise signal while preferentially extracting the components derived from thermoelectric power. The specific configuration of the circuit in the signal processing unit 5 is the same as described above.

[0041] Note that the configurations of the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b for making the sign of the second thermoelectric power opposite to that of the first thermoelectric power based on the heat flux J are not limited to the mode of magnetically inverting the polarity of the thermoelectric conversion element 41. FIG. 5 is a diagram showing another example of the element unit shown in FIG. 4. In the other example shown in FIG. 5, for example, by inverting the connection mode of the thermoelectric conversion element 41 between the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b, the signs of the thermoelectric powers of both are inverted. In this case, the spontaneous magnetization Ma of the thermoelectric conversion element 41 of the first thermoelectric conversion unit 4a and the spontaneous magnetization Mb of the thermoelectric conversion element 41 of the second thermoelectric conversion unit 4b are in the same direction. That is, the first thermoelectric conversion unit 4a and the second thermoelectric conversion unit 4b have the same polarity of the thermoelectric conversion element 41 alone, and by changing the connection mode of the wiring 42, the sign of the thermoelectric power with respect to the heat flux J of the entire thermoelectric conversion unit 4 is inverted.

[0042] 2.3. Third Embodiment of Element Unit 3 The element unit 3 according to the second embodiment includes two thermoelectric conversion units 4a and 4b whose polarities are inverted from each other, but the number of thermoelectric conversion units 4 included in the element unit 3 may be three or more. In this section, the element unit 3c as the element unit 3 according to the third embodiment will be described. FIG. 6 is a diagram showing the third embodiment of the element unit shown in FIG. 1. Here, mainly, among the elements of the third embodiment, the elements different from those of the second embodiment will be described, and the description of the configuration common to the second embodiment will be omitted by assigning the same numbers. Also, in FIG. 6, for convenience of explanation, the input terminals of the signal processing unit 5 are omitted.

[0043] The element section 3c may include, in addition to the first thermoelectric conversion section 4a and the second thermoelectric conversion section 4b, a third thermoelectric conversion section 4c and a fourth thermoelectric conversion section 4d as thermoelectric conversion sections. The third thermoelectric conversion section 4c outputs a voltage V5 as a first signal independently of the first thermoelectric conversion section 4a. The fourth thermoelectric conversion section 4d outputs a voltage V6 as a second signal. Voltages V5 and V6, like voltages V3 and V4, include a component derived from the thermoelectric voltage of the thermoelectric conversion elements 41 of each thermoelectric conversion section 4c and 4d, and a common noise signal. The third thermoelectric conversion section 4c and the fourth thermoelectric conversion section 4d are each equipped with at least one thermoelectric conversion element 41. As described above, each thermoelectric conversion element 41 generates a thermoelectric voltage based on the heat flow J. The third thermoelectric conversion section and the fourth thermoelectric conversion section are configured to reinforce each other's thermoelectric voltage by being connected in series. Here, the thermoelectric conversion elements 41 of the third thermoelectric conversion section 4c and the fourth thermoelectric conversion section 4d are defined to extend along a second in-plane direction that intersects with the first in-plane direction along the mounting surface 21. In Figure 6, the thermoelectric conversion elements 41 of the third thermoelectric conversion section 4c and the fourth thermoelectric conversion section 4d extend along the x-direction Dx, which is perpendicular to the y-direction Dy, from which the first thermoelectric conversion section 4a and the second thermoelectric conversion section 4b extend.

[0044] Here, the fourth thermoelectric conversion unit 4d is arranged so that a heat flux J flowing in the same direction as the heat flux J flowing through the third thermoelectric conversion unit 4c flows independently of the second thermoelectric conversion unit 4b, and is configured such that the sign of the second thermoelectromotive force is opposite to that of the first thermoelectromotive force based on the heat flux J. According to such a configuration, by taking the difference between the first signal and the second signal in a plurality of in-plane directions, for example, it is possible to provide the measurement device 1 that can easily reduce the noise signal with respect to the component of the thermoelectromotive force even for noise with strong anisotropy or locality. In the present embodiment, in a state where the direction in which the thermoelectric conversion element 41 of the first thermoelectric conversion unit 4a (and the second thermoelectric conversion unit 4b) extends intersects with the direction in which the third thermoelectric conversion unit 4c (and the fourth thermoelectric conversion unit 4d) extends, the directions of the spontaneous magnetizations Ma, Mb (or Mc, Md) of the thermoelectric conversion elements 41 of the paired thermoelectric conversion units 4a, 4b (or thermoelectric conversion units 4c, 4d) are reversed. Thereby, the polarities of the thermoelectric conversion elements 41 of the paired thermoelectric conversion units are reversed. Note that the control of the polarities of these thermoelectric conversion units 4a to 4d (that is, the sign of the thermoelectromotive force with respect to the direction of the heat flux J) is not limited to the method by controlling the direction of the spontaneous magnetization and is arbitrary. For example, a method of changing the connection mode of the wiring 42 as described above may be used.

[0045] [Others] Each of the above embodiments can be appropriately changed, for example, in the following manners.

[0046] The signal processing unit 5 is not limited to the analog circuit described above and may be incorporated as a digital circuit. Further, the signal processing unit 5 does not have to be incorporated on the same substrate 2 as the thermoelectric conversion unit 4 as the element unit 3. For example, the signal processing unit 5 may be implemented as a signal processing device or a computer outside the element unit 3 and further outside the measurement device 1.

[0047] The substrate 2 is not limited to a flat plate shape and may include a curved surface or a bending point. The substrate 2 may be a so-called flexible substrate that can be deformed.

[0048] In the above embodiment, the insulating layers are formed using the adhesive layers Gr1 and Gr2, but the formation mode of the insulating layer is not limited to this. For example, the insulating layer may be realized using a solid insulating plate or by forming an insulating film on the surface of the housing B.

[0049] The number of thermoelectric elements 41 included in one thermoelectric conversion unit 4 is not limited to multiple; it may be just one. In this case, the reference terminal 45 may be provided at the midpoint in the longitudinal direction of one thermoelectric element 41.

[0050] In the above embodiment, the first signal and the second signal were voltages, but they may also be currents or powers. In other words, the first signal and the second signal can be any signals that correlate with thermoelectric power.

[0051] The product may be provided in any of the following embodiments.

[0052] (1) A measuring device comprising a substrate to which heat from a target to be measured is conducted, and at least one thermoelectric conversion unit, wherein the substrate has a mounting surface, and the thermoelectric conversion unit is provided on the substrate such that a heat flow is generated by the heat transmitted through the mounting surface, and is configured to output a first signal and a second signal, wherein the first signal includes a first thermoelectric power generated by the heat flow and a first noise signal based on a disturbance applied to the thermoelectric conversion unit, and the second signal includes a second thermoelectric power generated by the heat flow and a second noise signal based on the disturbance, wherein the first thermoelectric power and the second thermoelectric power are output with inverted signs for the same heat flow, and the first noise signal and the second noise signal are configured to be generated with the same sign for the same disturbance regardless of the direction of the heat flow flowing to the thermoelectric conversion unit.

[0053] With this configuration, by taking the difference between the first signal and the second signal, it is possible to provide a measuring device that can easily reduce noise signals with respect to the thermoelectric power component.

[0054] (2) The measuring device described in (1) above, wherein the thermoelectric conversion unit comprises at least one thermoelectric conversion element, a first terminal, a second terminal, and a reference terminal, the thermoelectric conversion element generates a thermoelectric voltage based on the heat flow and is configured to amplify the thermoelectric voltage by being connected in series with each other, the first terminal and the second terminal are connected to a series connection of the thermoelectric conversion elements to output the thermoelectric voltage to the outside, the reference terminal is connected between the first terminal and the second terminal on a circuit defined by the series connection of the thermoelectric conversion elements, the first signal is a signal generated between the first terminal and the reference terminal, and the second signal is a signal generated between the second terminal and the reference terminal, the measuring device.

[0055] This configuration makes it possible to provide a measuring device that can easily reduce noise signals in the thermoelectric power component with a simple configuration.

[0056] (3) The measuring device described in (2) above, wherein the reference terminal is connected such that the difference between the resistance value between the first terminal and the reference terminal and the resistance value between the second terminal and the reference terminal is less than or equal to a specified allowable value.

[0057] (4) A measuring device according to any one of (1) to (3) above, further comprising an insulating layer and a conductive shield, wherein the conductive shield is electrically conductive and covers the thermoelectric conversion unit so as to sandwich the substrate and the thermoelectric conversion unit through the insulating layer.

[0058] This configuration makes it possible to reduce electromagnetic disturbances such as hum noise that may be applied to the thermoelectric conversion section.

[0059] (5) The measuring device described in (4) above, wherein the substrate includes a surface opposite to the mounting surface described above in the thickness direction of the substrate, and the conductive shield includes a substrate support portion directly connected to the opposite surface.

[0060] This configuration makes it possible to reduce electromagnetic disturbances that may be applied to the thermoelectric conversion section while suppressing an unintentional increase in the size of the measuring device.

[0061] (6) A measuring device according to any one of (1) to (5) above, wherein the at least one thermoelectric conversion unit includes a first thermoelectric conversion unit and a second thermoelectric conversion unit, the first thermoelectric conversion unit outputs the first signal, and the second thermoelectric conversion unit is arranged such that a heat flow flows in the same direction as the heat flow flowing in the first thermoelectric conversion unit, and is configured such that the sign of the second thermoelectric power is opposite to that of the first thermoelectric power based on the heat flow, thereby outputting the second signal.

[0062] With this configuration, a measuring device can be provided that can reduce noise signals with respect to the thermoelectric power component by taking the difference between the first signal and the second signal.

[0063] (7) The measuring device described in (6) above, wherein each of the first thermoelectric conversion unit and the second thermoelectric conversion unit comprises at least one first thermoelectric conversion element, each of the first thermoelectric conversion elements generates a thermoelectric voltage based on the heat flow, and is configured to reinforce the thermoelectric voltage by being connected in series with each of the first thermoelectric conversion unit and the second thermoelectric conversion unit, and the first thermoelectric conversion element is defined to extend along a first in-plane direction along the surface described above.

[0064] (8) In the measuring device described in (7) above, the thermoelectric conversion unit further includes a third thermoelectric conversion unit and a fourth thermoelectric conversion unit, wherein the third thermoelectric conversion unit outputs the first signal independently of the first thermoelectric conversion unit, and the fourth thermoelectric conversion unit is arranged such that a heat flow flows in the same direction as the heat flow flowing in the third thermoelectric conversion unit, independently of the second thermoelectric conversion unit, and is configured such that the sign of the second thermoelectric power is opposite to that of the first thermoelectric power based on the heat flow, A measuring device that outputs a signal 2, wherein the third thermoelectric conversion unit and the fourth thermoelectric conversion unit each comprise at least one second thermoelectric conversion element, each of the second thermoelectric conversion elements generates a thermoelectric voltage based on the heat flow, and is configured to reinforce the thermoelectric voltage by being connected in series with each of the third thermoelectric conversion unit and the fourth thermoelectric conversion unit, and the second thermoelectric conversion element is defined to extend along a second in-plane direction that intersects the first in-plane direction along the aforementioned surface.

[0065] With this configuration, by taking the difference between the first signal and the second signal in multiple in-plane directions, it is possible to provide a measuring device that can easily reduce noise signals with respect to the thermoelectric component, even in the case of noise with strong anisotropy or locality.

[0066] (9) A measuring device according to any one of (1) to (8) above, further comprising a signal processing unit, wherein the signal processing unit is configured to acquire the first signal and the second signal output from the thermoelectric conversion unit and to output the difference between the acquired first signal and the second signal. Of course, this is not limited to this.

[0067] For example, the following embodiments may be provided independently of or in combination with the above embodiments.

[0068] (a) A measuring device comprising a substrate to which heat from a target to be measured is conducted, at least one thermoelectric conversion unit, an insulating layer, and a conductive shield, wherein the substrate has a mounting surface, the thermoelectric conversion unit is provided on the substrate such that a heat flow is generated by the heat transmitted through the mounting surface, and the conductive shield is electrically conductive and covers the thermoelectric conversion unit so as to sandwich the substrate and the thermoelectric conversion unit through the insulating layer.

[0069] Finally, while various embodiments relating to this disclosure have been described, these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0070] 1: Measuring device, 2: Substrate, 21: Mounting surface, 22: Opposite side, 3: Element section, 3a: Element section, 3b: Element section, 3c: Element section, 4: Thermoelectric conversion section, 4a: First thermoelectric conversion section, 4b: Second thermoelectric conversion section, 4c: Third thermoelectric conversion section, 4d: Fourth thermoelectric conversion section, 41, 41a: Thermoelectric conversion element, 42: Wiring, 43: First terminal, 44: Second terminal, 45: Reference terminal, 5: Signal processing section, 51: Input terminal, 51a: Input terminal, 51b: Input terminal, 52: Input terminal, 52a: Input terminal, 52b: Input terminal, 53: Input terminal, 54: Output terminal, 100: Measurement target, B: Housing, B1: Substrate support part, B2: Top surface part, Dx: x direction, Dy: y direction, Dz: z direction, Gr1: Adhesive layer, Gr2: Adhesive layer, J: Heat flow, M, Ma to Md: Spontaneous magnetization, V1 to V6: Voltage, Vout: Output signal

Claims

1. A measuring device comprising a substrate to which heat from a target to be measured is conducted, and at least one thermoelectric conversion unit, wherein the substrate has a mounting surface, and the thermoelectric conversion unit is provided on the substrate such that a heat flow is generated by the heat transmitted through the mounting surface, and is configured to output a first signal and a second signal, the first signal includes a first thermoelectric power generated by the heat flow and a first noise signal based on a disturbance applied to the thermoelectric conversion unit, the second signal includes a second thermoelectric power generated by the heat flow and a second noise signal based on the disturbance, the first thermoelectric power and the second thermoelectric power are output with inverted signs for the same heat flow, and the first noise signal and the second noise signal are configured to be generated with the same sign for the same disturbance regardless of the direction of the heat flow flowing to the thermoelectric conversion unit.

2. The measuring device according to claim 1, wherein the thermoelectric conversion unit comprises at least one thermoelectric conversion element, a first terminal, a second terminal, and a reference terminal, the thermoelectric conversion element generates a thermoelectric electromotive force based on the heat flow and is configured to reinforce the thermoelectric electromotive force by being connected in series with each other, the first terminal and the second terminal are connected to a series connection of the thermoelectric conversion elements so as to output the thermoelectric electromotive force to the outside, the reference terminal is connected between the first terminal and the second terminal on a circuit defined by the series connection of the thermoelectric conversion elements, the first signal is a signal generated between the first terminal and the reference terminal, and the second signal is a signal generated between the second terminal and the reference terminal.

3. The measuring device according to claim 2, wherein the reference terminal is connected such that the difference between the resistance value between the first terminal and the reference terminal and the resistance value between the second terminal and the reference terminal is less than or equal to a specified allowable value.

4. A measuring device according to any one of claims 1 to 3, further comprising an insulating layer and a conductive shield, wherein the conductive shield is electrically conductive and covers the thermoelectric conversion unit so as to sandwich the substrate and the thermoelectric conversion unit through the insulating layer.

5. A measuring device according to claim 4, wherein the substrate includes a surface opposite to the mounting surface described above in the thickness direction of the substrate, and the conductive shield comprises a substrate support portion directly connected to the opposite surface.

6. A measuring device according to any one of claims 1 to 5, wherein the at least one thermoelectric conversion unit includes a first thermoelectric conversion unit and a second thermoelectric conversion unit, the first thermoelectric conversion unit outputs a first signal, and the second thermoelectric conversion unit is arranged such that a heat flow flows in the same direction as the heat flow flowing in the first thermoelectric conversion unit, and is configured such that the sign of the second thermoelectric power is opposite to that of the first thermoelectric power based on the heat flow, thereby outputting a second signal.

7. A measuring device according to claim 6, wherein each of the first thermoelectric conversion unit and the second thermoelectric conversion unit comprises at least one first thermoelectric conversion element, each of the first thermoelectric conversion elements generates a thermoelectric voltage based on the heat flow, and is configured to reinforce the thermoelectric voltage by being connected in series with each of the first thermoelectric conversion unit and the second thermoelectric conversion unit, and the first thermoelectric conversion element is defined to extend along a first in-plane direction along the surface described above.

8. The measuring device according to claim 7, wherein the thermoelectric conversion unit further includes a third thermoelectric conversion unit and a fourth thermoelectric conversion unit, the third thermoelectric conversion unit outputs the first signal independently of the first thermoelectric conversion unit, the fourth thermoelectric conversion unit is arranged independently of the second thermoelectric conversion unit so that a heat flow flows in the same direction as the heat flow flowing in the third thermoelectric conversion unit, and is configured such that the sign of the second thermoelectric power is opposite to that of the first thermoelectric power based on the heat flow, thereby outputting the second signal, the third thermoelectric conversion unit and the fourth thermoelectric conversion unit each include at least one second thermoelectric conversion element, each of the second thermoelectric conversion elements generates a thermoelectric power based on the heat flow, and is configured to reinforce the thermoelectric power by being connected in series with each other in the third thermoelectric conversion unit and the fourth thermoelectric conversion unit, respectively. The measuring device is defined such that the second thermoelectric conversion element extends along a second in-plane direction that intersects the first in-plane direction along the aforementioned surface.

9. A measuring device according to any one of claims 1 to 8, further comprising a signal processing unit, wherein the signal processing unit is configured to acquire the first signal and the second signal output from the thermoelectric conversion unit and to output the difference between the acquired first signal and the second signal.

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