Module and heat flow sensor

Abstract

The module 1a is provided with a first heat flow detection unit 10 and a second heat flow detection unit 20. The first heat flow detection unit (10) and the second heat flow detection unit (20) are disposed on the substrate (30). The first heat flow detection unit (10) includes a first thermoelectric conversion unit (11) and a first connection unit (12). The first thermoelectric conversion unit (11) forms a plurality of first fine lines (11a). The first connection part (12) electrically connects the first thin wires (11a) to each other. The second heat flow detection unit (20) includes a second thermoelectric conversion unit (21) and a second connection unit (22). The second thermoelectric conversion unit (21) forms a plurality of second fine lines (21a). The second connection section 22 electrically connects the second thin wires 21a to each other. The plurality of first fine lines 11a and the plurality of second fine lines 21a extend parallel to each other.

Description

Technical Field

[0001] The invention relates to a module and a heat flow sensor. Background Art

[0002] Conventionally, there is known a thermoelectric conversion module that can detect internal heat flux distribution.

[0003] For example, Patent Document 1 describes a thermoelectric conversion module in which a plurality of thermoelectric conversion element pairs are arranged on a surface and connected in series, wherein the thermoelectric conversion element pairs are formed by connecting an n-type thermoelectric conversion element and a p-type thermoelectric conversion element via an electrode plate. The thermoelectric conversion module is a π-type thermoelectric conversion module having a first output terminal, a second output terminal, and an intermediate output terminal. The first output terminal and the second output terminal are formed at a thermoelectric conversion element pair at one end and a thermoelectric conversion element pair at the other end, respectively, among the plurality of thermoelectric conversion element pairs connected in series. The intermediate output terminal is formed at any position between the thermoelectric conversion element pair at one end and the thermoelectric conversion element pair at the other end.

[0004] In the aforementioned thermoelectric conversion module, the potential difference generated in each thermoelectric conversion element pair varies according to the heat flux applied to each thermoelectric conversion element pair. Therefore, by measuring the voltage generated in any of the multiple thermoelectric conversion element pairs using the intermediate output terminal, the heat flux distribution applied to the thermoelectric conversion module can be detected.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-132113 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] The demand for heat-related monitoring is increasing in areas such as monitoring physical conditions in the Internet of Things (IoT) society and thermal management in technical fields such as electric vehicle (EV) batteries and high-speed data processing chips. To meet this demand, the use of modules equipped with thermoelectric converters for thermal sensing is being considered. If such modules can detect heat flow at multiple locations on a thermally sensed object, their value will increase significantly.

[0010] While the thermoelectric conversion module described in Patent Document 1 can detect internal heat flux distribution, it requires arranging multiple pairs of thermoelectric conversion elements, each consisting of n-type thermoelectric conversion elements connected to p-type thermoelectric conversion elements via electrode plates. This thermoelectric conversion module is considered to have a complex structure, requiring complex processes for its manufacture, and thus likely increasing manufacturing costs. Therefore, from the perspective of productivity, the thermoelectric conversion module described in Patent Document 1 requires further research.

[0011] In view of such circumstances, the present invention provides a module that can detect heat flow at multiple locations and is advantageous from the viewpoint of productivity.

[0012] Means for solving problems

[0013] The present invention provides a module comprising:

[0014] a first heat flow detection portion disposed on the substrate and comprising a first thermoelectric conversion portion forming a plurality of first thin wires and a first connection portion electrically connecting the first thin wires to each other; and

[0015] a second heat flow detection portion, which is disposed on the substrate and includes a second thermoelectric conversion portion forming a plurality of second thin wires and a second connection portion electrically connecting the second thin wires to each other;

[0016] The plurality of first thin lines and the plurality of second thin lines extend parallel to each other.

[0017] Furthermore, the present invention provides a thermal flow sensor including the above module.

[0018] Effects of the Invention

[0019] The above-mentioned module can detect heat flow at multiple locations and is advantageous from the perspective of productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [ Figure 1 ] Figure 1 This is a plan view showing an example of a module according to the present invention.

[0021] [ Figure 2 ] Figure 2 It is a plan view showing an example of a module according to a reference example.

[0022] [ Figure 3 ] Figure 3 Graph showing the relationship between the magnetization of the thin wires of the thermoelectric conversion part and the external magnetic field.

[0023] [ Figure 4 ] Figure 4 It shows Figure 1 A top view of an example of a method for manufacturing a module shown.

[0024] [ Figure 5 ] Figure 5 This is a diagram showing an example of a sensor according to the present invention.

[0025] [ Figure 6 ] Figure 6 This is a plan view showing another example of the module according to the present invention.

[0026] [ Figure 7 ] Figure 7 This is a diagram schematically showing a method for measuring the internal stress of a crystal. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following description is merely illustrative of the present invention, and the present invention is not limited to the following embodiments.

[0028] like Figure 1 As shown, the module 1a includes a first heat flow detection portion 10 and a second heat flow detection portion 20. The first heat flow detection portion 10 and the second heat flow detection portion 20 are arranged on a substrate 30. The first heat flow detection portion 10 and the second heat flow detection portion 20 are arranged, for example, on a surface of the substrate 30 that forms the same plane. The first heat flow detection portion 10 includes a first thermoelectric conversion portion 11 and a first connecting portion 12. The first thermoelectric conversion portion 11 forms a plurality of first thin wires 11a. The first connecting portion 12 electrically connects the first thin wires 11a to each other. The first connecting portion 12 forms a plurality of thin wires 12a. The second heat flow detection portion 20 includes a second thermoelectric conversion portion 21 and a second connecting portion 22. The second thermoelectric conversion portion 21 forms a plurality of second thin wires 21a. The second connecting portion 22 electrically connects the second thin wires 21a to each other. The second connecting portion 22 forms a plurality of thin wires 22a. The plurality of first thin wires 11a and the plurality of second thin wires 21a extend parallel to each other.

[0029] According to the module 1a, heat flow can be detected at multiple locations by configuring the first heat flow detection part 10 and the second heat flow detection part 20 on the same substrate 30. The first thermoelectric conversion part 11 and the second thermoelectric conversion part 21 are respectively configured to form a plurality of first thin wires 11a and a plurality of second thin wires 21a. Therefore, compared with the case where a plurality of thermoelectric conversion element pairs are arranged by connecting n-type thermoelectric conversion elements and p-type thermoelectric conversion elements via electrode plates, the module 1a has a simple structure, and complex processes are not easily required in the manufacture of the module 1a. In addition, it is easy to reduce the amount of necessary materials in the manufacture of the module 1a. Therefore, the module 1a is advantageous from the perspective of productivity.

[0030] As described above, the plurality of first thin wires 11a and the plurality of second thin wires 21a extend parallel to each other. Therefore, for example, it is possible to implement a process of imparting prescribed thermoelectric conversion characteristics to the above-mentioned thin wires at one time, which makes it easy to improve the productivity of the module 1a. Furthermore, it is not easy to produce deviations in the characteristics of heat flow detection in the first heat flow detection section 10 and the second heat flow detection section 20. Therefore, according to the module 1a, it is easy to detect heat flow at multiple locations with high precision. For example, when the first heat flow detection section 10 and the second heat flow detection section 20 are arranged along the same plane, the plurality of first thin wires 11a and the plurality of second thin wires 21a extend parallel to each other.

[0031] like Figure 1 As shown, the plurality of first thin wires 11a and the plurality of second thin wires 21a extend, for example, along the Y-axis direction. In the figure, the X-axis, Y-axis, and Z-axis are orthogonal to each other. The Z-axis is perpendicular to the surface of the substrate 30. The first thermoelectric conversion section 11 and the second thermoelectric conversion section 21 are arranged, for example, along a plane parallel to the XY plane.

[0032] The substrate 30 has, for example, a flat main surface. This main surface is, for example, a surface parallel to the XY plane.

[0033] Figure 2 1 is a top view of the module 1x involved in the reference example. Except for the parts specially explained, the module 1x is constructed in the same manner as the module 1a. In the module 1x, the plurality of second thin wires 21a extend non-parallel to the plurality of first thin wires 11a. In other words, the straight line formed by extending the plurality of second thin wires 21a intersects the straight line formed by extending the plurality of first thin wires 11a. In the module 1x, the first thermoelectric conversion part 11 and the second thermoelectric conversion part 21 are rotationally symmetric with respect to a rotation axis passing through a specific point P1 on the XY plane and parallel to the Z axis. In the module 1x, in order to reduce the deviation of the characteristics of the heat flow detection in the first heat flow detection part 10 and the second heat flow detection part 20, it is necessary to implement a process for imparting prescribed thermoelectric conversion characteristics to the thin wires contained in the first thermoelectric conversion part 11 and the second thermoelectric conversion part 21, respectively. This is not advantageous from the perspective of the productivity of the module. In addition, assuming that the processing of giving specified thermoelectric conversion characteristics to the fine wires contained in the first thermoelectric conversion part 11 and the second thermoelectric conversion part 21 is implemented at one time, the deviation of the characteristics of heat flow detection in the first heat flow detection part 10 and the second heat flow detection part 20 is likely to become larger, making it difficult to detect heat flow with high precision in multiple locations.

[0034] like Figure 1 As shown, the lengths of the plurality of first thin wires 11a in the first thermoelectric conversion section 11 are substantially the same. The coefficient of variation of the lengths of the first thin wires 11a in the first thermoelectric conversion section 11 is not limited to a specific value.

[0035] The second thermoelectric conversion part 21 includes, for example, second thin wires 21a having different lengths. According to such a structure, it is easy to increase the degree of freedom of the shape of the first thermoelectric conversion part 11 and the second thermoelectric conversion part 21, and it is easy to adjust the shape of the first thermoelectric conversion part 11 and the second thermoelectric conversion part 21 according to the shape of the substrate 30. For example, it is easy to reduce the size of the substrate 30 in a specific direction. The sensitivity of heat flow detection of the first thermoelectric conversion part 11 and the second thermoelectric conversion part 21 is, for example, proportional to the sum of the lengths L1 of the plurality of first thin wires 11a and the sum of the lengths L2 of the plurality of second thin wires 21a, respectively. Therefore, by making the second thermoelectric conversion part 21 include second thin wires 21a having different lengths, it is easy to make the area of ​​the first thermoelectric conversion part 11 consistent with the area of ​​the second thermoelectric conversion part 21 and the width of the first thin wire 11a consistent with the width of the second thin wire 21a, and at the same time make the sensitivity of heat flow detection of the first heat flow detection part 10 consistent with that of the second heat flow detection part 20.

[0036] The coefficient of variation of the length of the second thin wire 21a in the second thermoelectric conversion section 21 is not limited to a specific value. Its coefficient of variation is, for example, greater than the coefficient of variation of the length of the first thin wire 11a in the first thermoelectric conversion section 11. This coefficient of variation is, for example, 0.01 to 0.1, 0.02 to 0.09, or 0.03 to 0.08. In this specification, the coefficient of variation is a weighted coefficient of variation determined according to the following equations (1) to (3). i is the length of each thin line. wav is the weighted average of the lengths of the thin lines, and σ is the standard deviation of the weighted average. i is the weight of the length of each thin line, which is the ratio of the length of each thin line to the total length of the thin lines. i is the weighted average x subtracted from the length of each thin line wav The difference is the residual, and n is the number of thin lines.

[0037] Weighted coefficient of variation = σ / x wav Formula (1)

[0038] [Mathematical formula 1]

[0039]

[0040] [Mathematical formula 2]

[0041]

[0042] The sensitivity of heat flow detection in the first heat flow detection section 10 and the second heat flow detection section 20 is proportional to, for example, the sum L1 of the lengths of the plurality of first thin wires 11a and the sum L2 of the lengths of the plurality of second thin wires 21a, respectively. Therefore, to reduce variations in the heat flow detection characteristics in the first heat flow detection section 10 and the second heat flow detection section 20, the difference between the sum L1 and the sum L2 is preferably small. The ratio L2 / L1 of the sum L2 to the sum L1 is, for example, 0.90 to 1.10, preferably 0.95 to 1.05, and more preferably 0.99 to 1.01.

[0043] The first thermoelectric conversion section 11 generates an electromotive force along the length of the first thin wire 11a, for example, by utilizing heat flow in a direction perpendicular to the surface of the substrate 30 (the Z-axis direction). Furthermore, the second thermoelectric conversion section 21 generates an electromotive force along the length of the second thin wire 21a, for example, by utilizing heat flow in a direction perpendicular to the surface of the substrate 30. This configuration easily improves the sensitivity of heat flow detection in the first and second heat flow detection sections 10 and 20.

[0044] Each of the first thermoelectric conversion section 11 and the second thermoelectric conversion section 21 generates an electromotive force, for example, through the magnetoelectric effect. The magnetoelectric effect that generates the electromotive force in each of the first thermoelectric conversion section 11 and the second thermoelectric conversion section 21 can be the anomalous Nernst effect or the spin Seebeck effect. These magnetoelectric effects generate an electromotive force in a direction perpendicular to the magnetization and perpendicular to the heat flow.

[0045] For example, the first thermoelectric conversion portion 11 and the second thermoelectric conversion portion 21 are magnetized in the width direction (X-axis direction) perpendicular to the longitudinal direction (Y-axis direction) of the first thin wire 11a and the second thin wire 21a and extending along the surface of the substrate 30. With this configuration, when heat flow occurs in the direction perpendicular to the surface of the substrate 30 (Z-axis direction), an electromotive force is easily generated in the longitudinal direction of the first thin wire 11a and the second thin wire 21a due to the magnetoelectric effect.

[0046] The first thin wire 11a and the second thin wire 21a each contain, for example, a predetermined magnetic substance. The magnetic substance contained in the first thin wire 11a has, for example, an easy magnetization axis in the width direction (X-axis direction) perpendicular to the length direction of the first thin wire 11a and extending along the surface of the substrate 30. Furthermore, the magnetic substance contained in the second thin wire 21a has, for example, an easy magnetization axis in the width direction (X-axis direction) perpendicular to the length direction of the second thin wire 21a and extending along the surface of the substrate 30. According to such a configuration, the first thermoelectric conversion portion 11 and the second thermoelectric conversion portion 21 can easily exert the desired thermoelectric performance, respectively, and can easily improve the sensitivity of heat flow detection in the first heat flow detection portion 10 and the second heat flow detection portion 20.

[0047] The difference σ2-σ1 obtained by subtracting the first internal stress σ1 of the first thin wire 11a from the second internal stress σ2 of the first thin wire 11a is not limited to a specific value. In the first thin wire 11a, the difference σ2-σ1 is, for example, greater than 50 MPa. The difference σ2-σ1 obtained by subtracting the first internal stress σ1 of the second thin wire 21a from the second internal stress σ2 of the second thin wire 21a is not limited to a specific value. In the second thin wire 21a, the difference σ2-σ1 is, for example, greater than 50 MPa. The first internal stress σ1 is the internal stress of the first thin wire 11a or the second thin wire 21a in the first direction parallel to the surface of the substrate 30. On the other hand, the second internal stress σ2 is the internal stress of the first thin wire 11a or the second thin wire 21a in the second direction parallel to the surface of the substrate 30 and perpendicular to the first direction. According to such a structure, the first thin wire 11a or the second thin wire 21a easily has an easy magnetization axis in the width direction of the first thin wire 11a and the width direction of the second thin wire 21a, respectively. Therefore, the first thermoelectric conversion section 11 and the second thermoelectric conversion section 21 can each easily exhibit desired thermoelectric performance, and the sensitivity of heat flow detection in the first heat flow detection section 10 and the second heat flow detection section 20 can be easily improved. In this specification, positive internal stress indicates tensile stress, and negative internal stress indicates compressive stress.

[0048] Figure 3 Graph showing an example of the relationship between the magnetization of the first thin wire 11a and the second thin wire 21a and the external magnetic field. Figure 3 In the graph, the solid line shows the relationship between the magnetization of the first thin wire 11a and the second thin wire 21a in the second direction and the external magnetic field. The dotted line shows the relationship between the magnetization of the first thin wire 11a and the second thin wire 21a in the first direction and the external magnetic field. u With E u =(3 / 2)λσ. In this relationship, λ represents the magnetostriction constant of the magnetic body, and σ represents the internal stress of the magnetic body. Therefore, it can be understood that the larger the difference σ2-σ1 is, the greater the anisotropy of the magnetic properties of the first thin wire 11a and the second thin wire 21a in the second direction and the first direction becomes. Figure 3 As shown, by setting the difference σ2-σ1 of 50 MPa or greater in the magnetic properties of first and second thin wires 11a, 21a exhibits large anisotropy in the second and first directions. This large anisotropy in the magnetic properties makes it easier for first and second thin wires 11a, 21a, to have an easy magnetization axis in the second direction and a hard magnetization axis in the first direction. Consequently, first and second thin wires 11a, 21a, respectively, exhibit stable behavior with respect to an external magnetic field, allowing first and second thermoelectric conversion sections 11, 21, respectively, to exhibit their desired thermoelectric performance.

[0049] In each of the first thin wire 11a and the second thin wire 21a, the difference σ2-σ1 can be greater than 100 MPa, greater than 150 MPa, or greater than 200 MPa. The upper limit of the difference σ2-σ1 is not limited to a specific value. The difference σ2-σ1 is, for example, less than 900 MPa. In this case, even if a bending load in the second direction is applied to both ends of the first thin wire 11a and the second thin wire 21a, cracks are unlikely to occur in the first thin wire 11a and the second thin wire 21a.

[0050] The first internal stress σ1 can be a tensile stress or a compressive stress. The first internal stress σ1 is, for example, less than 900 MPa. Thus, in the first fine wire 11a and the second fine wire 21a, the difference σ2-σ1 can be easily adjusted to be greater than 50 MPa. Moreover, even if a bending load in the first direction is applied to both ends of the first fine wire 11a and the second fine wire 21a, cracks are not easily generated in the first fine wire 11a and the second fine wire 21a. The first internal stress σ1 is, for example, greater than -900 MPa. The first internal stress σ1 can be included in any range determined by all combinations of the lower limit value of any one of -900 MPa, -700 MPa, -500 MPa and -300 MPa and the upper limit value of any one of 900 MPa, 700 MPa, 500 MPa and 300 MPa.

[0051] The second internal stress σ2 can be a tensile stress or a compressive stress. The second internal stress σ2 is, for example, greater than -900 MPa. Thus, the difference σ2-σ1 can be easily adjusted to be greater than 50 MPa. The second internal stress σ2 is, for example, less than 900 MPa. In this case, even if a bending load in the second direction is applied to both ends of the first fine wire 11a and the second fine wire 21a, cracks are not easily generated in the first fine wire 11a and the second fine wire 21a. The second internal stress σ2 can be included in any range determined by all combinations of the lower limit value of any one of -900 MPa, -700 MPa, -500 MPa and -300 MPa and the upper limit value of any one of 900 MPa, 700 MPa, 500 MPa and 300 MPa.

[0052] The magnetostriction constant of the magnetic body contained in the first thin wire 11a and the second thin wire 21a can be a positive value or a negative value. For example, when the magnetostriction constant of the magnetic body is positive, the Y-axis direction corresponds to the first direction, and the X-axis direction corresponds to the second direction. On the other hand, when the magnetostriction constant of the magnetic body contained in the first thin wire 11a and the second thin wire 21a is negative, the X-axis direction corresponds to the first direction, and the Y-axis direction corresponds to the second direction. Figure 1As shown, the first fine wire 11a and the second fine wire 21a extend in the Y-axis direction. Therefore, considering the shape magnetic anisotropy, it is considered that in the first fine wire 11a and the second fine wire 21a, an easy magnetization axis is generated in the Y-axis direction, and a hard magnetization axis is generated in the X-axis direction. However, in the first fine wire 11a and the second fine wire 21a, when the difference σ2 - σ1 is 50 MPa or more, as described above, the magnetic properties of the first fine wire 11a and the second fine wire 21a have large anisotropy in the second direction and the first direction. Therefore, in the first fine wire 11a and the second fine wire 21a, an easy magnetization axis is likely to be generated in the X-axis direction, and the first fine wire 11a and the second fine wire 21a are likely to exhibit stable behavior with respect to an external magnetic field. As a result, the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 are likely to exhibit the desired thermoelectric performance.

[0053] The first fine wire 11a and the second fine wire 21a contain, for example, a substance showing an anomalous Nernst effect. The substance showing an anomalous Nernst effect is not limited to a specific substance. The substance showing an anomalous Nernst effect is, for example, a magnetic body having a saturation magnetization of 5×10 - 3 T or more or a substance having a band structure with Weyl points near the Fermi level. The magnetic body can be a ferrimagnetic body. The first fine wire 11a and the second fine wire 21a contain, for example, at least one substance selected from the group consisting of the following (i), (ii), (iii), (iv), and (v) as the substance showing an anomalous Nernst effect.

[0054] (i) A stoichiometric substance having a composition represented by Fe3X

[0055] (ii) A non-stoichiometric substance in which the composition ratio of Fe to X deviates from the substance of (i)

[0056] (iii) A substance obtained by substituting a part of the Fe sites of the substance of (i) or a part of the Fe sites of the substance of (ii) with a typical metal element or a transition element other than X

[0057] (iv) A substance having a composition represented by Fe3M1 1-x M2 x (0 < x < 1), and M1 and M2 are different typical elements

[0058] (v) A substance obtained by substituting a part of the Fe sites of the substance of (i) with a transition element other than X and substituting a part of the X sites of the substance of (i) with a typical metal element other than X

[0059] In the substances (i) to (v) above, X is a typical element or a transition element. Examples of X include Al, Ga, Ge, Sn, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Sc, Ni, Mn, or Co. In (iv) above, the combination of M1 and M2 is not limited to a specific combination as long as M1 and M2 are different typical elements. In (iv) above, examples of the combination of M1 and M2 include Ga and Al, Si and Al, or Ga and B.

[0060] The magnetic thin film 11 may contain Co 2 MnGa or Mn 3 Sn as a substance showing the anomalous Nernst effect.

[0061] The magnetostriction constant λ of the magnetic material contained in the first thin wire 11a and the second thin wire 21a is not limited to a specific value. The absolute value of the magnetostriction constant λ is, for example, 5×10 -6 As mentioned above, the magnetic anisotropy energy E of the magnetic body u With E u =(3 / 2)λσ. Therefore, the absolute value of the magnetostriction constant λ is 5×10 -6 In the above case, the anisotropy of the magnetic characteristics of the first thin wire 11 a and the second thin wire 21 a in the second direction and the first direction tends to increase.

[0062] The absolute value of the magnetostriction constant λ can be 10×10 -6 Above, it can also be 20×10 -6 above.

[0063] like Figure 1 As shown, in the first heat flow detection portion 10 , a plurality of first thin wires 11 a are electrically connected in series via a first connection portion 12 . Also, in the second heat flow detection portion 20 , a plurality of second thin wires 21 a are electrically connected in series via a second connection portion 22 .

[0064] like Figure 1 As shown, the first heat flow detection section 10 forms a zigzag pattern, for example. Furthermore, the second heat flow detection section 20 forms a zigzag pattern. With this configuration, even if the area where the first and second heat flow detection sections 10 and 20 are located is small, the sum of the lengths L1 of the first fine lines 11a and the sum of the lengths L2 of the second fine lines 21a can be easily increased. Therefore, even with a small area, the first and second heat flow detection sections 10 and 20 can easily detect heat flow with high sensitivity.

[0065] The dimension in the Z-axis direction of the first thin wire 11a and the second thin wire 21a, that is, the thickness, is not limited to a specific value. The thickness is, for example, less than 1000 nm. As a result, the amount of material used in the first thin wire 11a and the second thin wire 21a can be reduced, and the manufacturing cost of the module 1a can be easily reduced. In addition, wire breakage is less likely to occur in the first heat flow detection part 10 and the second heat flow detection part 20. The thickness of the first thin wire 11a and the second thin wire 21a is, for example, more than 5 nm. As a result, the module 1a can easily exhibit high durability.

[0066] The thickness of the first fine line 11a and the second fine line 21a can be included in any range determined by all combinations of any lower limit value of 5nm, 10nm, 20nm, 30nm and 50nm and any upper limit value of 1000nm, 750nm, 500nm, 400nm, 300nm and 200nm.

[0067] The dimension in the X-axis direction of the first thin wire 11a and the second thin wire 21a, that is, the width, is not limited to a specific value. The width is, for example, less than 500 μm. As a result, the amount of material used to form the magnetic thermoelectric converter in the thermoelectric conversion element 100 can be reduced, and the manufacturing cost of the thermoelectric conversion element 100 can be easily reduced. In addition, it is easy to arrange a large number of first thin wires 11a and second thin wires 21a in the X-axis direction, and it is easy to improve the sensitivity of heat flow detection in the first heat flow detection part 10 and the second heat flow detection part 20. The width of the first thin wire 11a and the second thin wire 21a is, for example, more than 0.1 μm. Wire breakage is not likely to occur in the first heat flow detection part 10 and the second heat flow detection part 20, and the module 1a is easy to exhibit high durability.

[0068] The widths of the first fine line 11a and the second fine line 21a can be included in any range determined by all combinations of any lower limit value of 0.1μm, 0.5μm, 1μm, 2μm, 5μm, 10μm, 20μm and 30μm and any upper limit value of 500μm, 400μm, 300μm, 200μm, 100μm and 50μm.

[0069] The dimension in the Z-axis direction of the thin wire 12a and the thin wire 22a, that is, the thickness, is not limited to a specific value. The thickness is, for example, less than 1000nm. As a result, the amount of material used to form the first connecting portion 12 and the second connecting portion 22 can be reduced, and the manufacturing cost of the module 1a can be easily reduced. In addition, wire breakage is less likely to occur in the first heat flow detection portion 10 and the second heat flow detection portion 20. The thickness of the thin wire 12a and the thin wire 22a is, for example, more than 5nm. As a result, the module 1a can easily exhibit high durability.

[0070] The thickness of the fine line 12a and the fine line 22a can be included in any range determined by all combinations of any lower limit value of 5nm, 10nm, 20nm, 30nm and 50nm and any upper limit value of 1000nm, 750nm, 500nm, 400nm, 300nm, 200nm and 100nm.

[0071] The width of the thin wire 12a and the thin wire 22a is not limited to a specific value. The width is, for example, less than 500 μm. As a result, the amount of material used to form the first connecting portion 12 and the second connecting portion 22 can be reduced, and the manufacturing cost of the module 1a can be easily reduced. In addition, it is easy to configure a large number of thin wires 12a and 22a, and it is easy to improve the sensitivity of heat flow detection in the first heat flow detection portion 10 and the second heat flow detection portion 20. The width of the thin wire 12a and the thin wire 22a is, for example, more than 0.1 μm. As a result, wire breakage is less likely to occur in the first heat flow detection portion 10 and the second heat flow detection portion 20, and the module 1a can easily exhibit high durability.

[0072] The width of the fine line 12a and the fine line 22a can be included in any range determined by all combinations of any lower limit value of 0.1μm, 0.5μm, 1μm, 2μm, 5μm, 10μm, 20μm and 30μm and any upper limit value of 500μm, 400μm, 300μm, 200μm, 100μm and 50μm.

[0073] The substrate 30 is not limited to a specific substrate as long as it can provide a surface for the first heat flow detection portion 10 and the second heat flow detection portion 20 to be arranged. The surface of the substrate 30 for the first heat flow detection portion 10 and the second heat flow detection portion 20 to be arranged is formed, for example, by a dielectric. The material forming the substrate 30 can be an organic polymer or an inorganic material such as glass and ceramic. Examples of organic polymers are polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acrylic resin (PMMA), polycarbonate (PC), polyimide (PI) or cycloolefin polymer (COP).

[0074] The substrate 30 has, for example, flexibility. For example, the substrate 30 has such elasticity that when a strip-shaped test piece made from the substrate 20 is wound around a cylindrical mandrel with a diameter of 10 cm so that both ends thereof face in the same direction, the test piece can be elastically deformed. The substrate may also be rigid.

[0075] The substrate 30 may be in a sheet, film, or plate shape, for example. The thickness of the substrate 30 is not limited to a specific thickness. The thickness of the substrate 30 is, for example, 4 to 250 μm.

[0076] The shape of the substrate 30 in a plan view is not limited to a specific shape. Figure 1 As shown, substrate 30 has, for example, a pair of end lines 32 that overlap when viewed from above by parallel movement. This configuration allows for efficient production of multiple modules 1a from a large or long substrate, which is advantageous from a productivity perspective. Each end line 32 can consist of a single line segment, multiple intersecting line segments, or include a curved portion such as an arc.

[0077] An example of a method for manufacturing the module 1a is described. For example, a film of the precursor of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 is formed on one main surface of a large or long substrate 30a using methods such as sputtering, chemical vapor deposition (CVD), pulsed laser deposition (PLD), ion plating, and plating. Next, as needed, the substrate 30a and the film of the precursor of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 are heated at a predetermined temperature. The temperature of the heating treatment is not limited to a specific temperature. The ambient temperature of the substrate 30a and the precursor of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 during the heating treatment is, for example, 50°C or more. Thus, the difference σ2-σ1 can be easily adjusted to the desired range. The ambient temperature of the substrate 30a and the precursor of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 during the heating treatment is above 100°C, above 150°C, or may be above 200°C, and the ambient temperature is, for example, below 300°C.

[0078] During the heat treatment, the time during which the ambient temperature of the substrate 30a is maintained at 50°C or higher is not limited to a specific value, but is, for example, 10 minutes to 3 hours.

[0079] For example, a photoresist is applied on the film of the precursor of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21, a photomask is arranged on the film and exposed, and then wet etching is performed. Thus, a plurality of thin lines arranged at prescribed intervals are formed. Next, a film of the precursor of the first connecting portion 12 and the second connecting portion 22 is formed on one main surface of the substrate 30a using methods such as sputtering, CVD, PLD, ion plating and plating. Next, a photoresist is applied on the film, a photomask is arranged on the film and exposed, and then wet etching is performed. Thus, the first connecting portion 12 and the second connecting portion 22 are formed, and the thin lines of the precursor of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 are electrically connected to each other. Like this, for example Figure 4 As shown, a plurality of semi-finished products 2a of the modules 1a are produced on one substrate 30a.

[0080] Next, each semi-finished product 2a is cut from the substrate 30a. In each semi-finished product 2a, the thin wires of the precursors of the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21 are magnetized to obtain the first thermoelectric conversion unit 11 and the second thermoelectric conversion unit 21. In this way, the module 1a is obtained.

[0081] Module 1a can be provided with an adhesive layer, for example. In this case, substrate 30 is positioned between the first and second thermoelectric conversion sections 11, 21, and the adhesive layer in the thickness direction of substrate 30. This allows module 1a to be attached to an object by pressing the adhesive layer against the object.

[0082] The adhesive layer may include, for example, a rubber-based adhesive, an acrylic adhesive, a silicone-based adhesive, or a urethane-based adhesive. Module 1a may also be provided with an adhesive layer and a release liner. In this case, the release liner covers the adhesive layer. Typically, the release liner is a film that can maintain the adhesive strength of the adhesive layer when covering the adhesive layer and can be easily peeled off from the adhesive layer. The release liner is, for example, a film made of a polyester resin such as PET. By peeling off the release liner, the adhesive layer can be exposed and module 1a can be attached to an article.

[0083] like Figure 5 As shown, for example, a sensor 5 including a module 1a can be provided. In the sensor 5, when a temperature gradient is generated in the thickness direction of the substrate 30, for example, an electromotive force is generated in the length direction (Y-axis direction) of the first thin wire 11a and the second thin wire 12a in the first thermoelectric conversion section 11 and the second thermoelectric conversion section 21, respectively. The sensor 5 processes the electrical signal based on the electromotive force output to the outside of the module 1a, thereby being able to detect, for example, the heat flux [W / m2] at the locations corresponding to the first thermoelectric conversion section 11 and the second thermoelectric conversion section 21. 2 ].

[0084] like Figure 5 As shown, the sensor 5 further includes, for example, a signal processing device 2. The signal processing device 2 processes the electrical signal output to the outside of the module 1a.

[0085] Module 1a can be modified from various perspectives. For example, module 1a can be modified to Figure 6 Module 1b is shown. Module 1b is constructed similarly to module 1a except for the parts mentioned above. The description of module 1a also applies to module 1b unless there is a technical conflict.

[0086] like Figure 6As shown, in module 1b, the lengths of the plurality of second thin wires 21a in the second thermoelectric conversion section 21 are substantially the same. The coefficient of variation of the lengths of the second thin wires 21a in the second thermoelectric conversion section 21 is not limited to a specific value. This coefficient of variation is, for example, substantially the same as the coefficient of variation of the lengths of the first thin wires 11a in the first thermoelectric conversion section 11.

[0087] Example

[0088] The present invention will be described in more detail below using examples. However, the present invention is not limited to the following examples. First, the evaluation method of the examples will be described.

[0089] <Example 1>

[0090] In top view, Figure 1 Three conductive paths a, b, and c are formed in a zigzag pattern on a 50μm-thick polyethylene terephthalate (PET) film with a V-shape as shown. The PET film extends in a strip-like pattern along two line segments forming a 150° angle. In a top view, conductive paths a and c are located at the ends of the PET film, while conductive path b is located in the center. Conductive paths a and b are arranged along one of the two line segments forming a 150° angle. The PET film is 10mm wide.

[0091] Conductive paths a, b, and c are formed as described below. Using a target containing Fe and Ga, a magnetic thin film with a thickness of 96 nm is formed by DC magnetron sputtering. In this target, the atomic ratio is such that the content of Fe:Ga is 3:1. In addition, the temperature of the PET film is adjusted to 100°C. The PET film with the magnetic thin film is heat-treated in an environment of 150°C for 30 minutes. Next, a photoresist is applied to the magnetic thin film, a photomask is placed on the magnetic thin film, exposure is performed, and then wet etching is performed. Thus, 62 fine lines containing FeGa are formed at predetermined intervals. The width of each linear pattern containing FeGa is 100 μm. Then, using a target containing Cu, a Cu thin film with a thickness of 100 nm is formed by DC magnetron sputtering. A photoresist is applied to the Cu thin film, a photomask is placed on the Cu thin film, exposure is performed, and then wet etching is performed. Thus, fine lines containing Cu with a width of 40 μm are formed. A pair of adjacent FeGa-containing thin wires are electrically connected to each other by a Cu-containing thin wire, thereby forming conductive paths a, b, and c forming a zigzag pattern.

[0092] In the conductive paths a and b, the length of each of the 62 FeGa thin wires is approximately equal to 7 mm. In the conductive path c, Figure 1As shown, the 62 FeGa-containing thin wires include FeGa-containing thin wires of different lengths. The coefficient of variation of the length of the FeGa-containing thin wires in the conductive path c calculated according to formulas (1) to (3) is 0.03. In the conductive paths a, b and c, the 186 FeGa-containing thin wires are parallel to each other and extend in a direction perpendicular to one of the two line segments forming an angle of 150° mentioned above. In each of the conductive paths a, b and c, the total length of the 62 FeGa-containing thin wires is the same. The conductive paths a, b and c are rectangular when viewed from above, and the short side of the outer shape of each conductive path extends in the width direction of the PET film.

[0093] The FeGa-containing thin wires were magnetized in a width direction parallel to the main surface of the PET film and perpendicular to the longitudinal direction of the FeGa-containing thin wires using an electromagnet having a central magnetic flux density of 0.5 T. Thus, the module according to Example 1 was obtained.

[0094] <Example 2>

[0095] The module of Example 2 was obtained by following the same operation as Example 1 except for the following aspects. Figure 6 As shown, in conductive path c, the length of each of the 62 FeGa-containing thin wires is adjusted to be approximately equal, 7 mm. Conductive paths a, b, and c are formed so that they can overlap by moving parallel to the main surface of the PET film. The width of the PET film is 20.5 mm.

[0096] <Comparative Example 1>

[0097] The module of Comparative Example 1 was obtained by operating in the same manner as in Example 1 except for the following aspects. Conductive paths α and β were formed instead of conductive paths a, b, and c. Conductive path α and conductive path β were arranged at the end of the PET film. Conductive path α was formed in the same manner as conductive path a. Conductive path β was formed in the same manner as conductive path c except for the parts specifically stated. The thin wire containing FeGa in conductive path β was non-parallel to the thin wire containing FeGa in conductive path α. Figure 2 As shown, the FeGa-containing fine wires in conductive path α extend perpendicularly to one of the two line segments forming a 150° angle, while the FeGa-containing fine wires in conductive path β extend perpendicularly to the other of the two line segments. Conductive paths α and β are rectangular in plan view, with the short sides of each conductive path extending in the width direction of the PET film. Conductive paths α and β are rotationally symmetrical. The width of the PET film is 10 mm.

[0098] Using an electromagnet having a central magnetic flux density of 0.5 T, the FeGa-containing thin wires in the conductive paths α and β were magnetized in a direction parallel to the main surface of the PET film and perpendicular to the longitudinal direction of the FeGa-containing thin wires in the conductive path α.

[0099] [Magnetic properties]

[0100] The magnetic properties of the FeGa-containing thin wires of the modules of each embodiment and each comparative example were measured using the small refrigerant-free physical property measurement system PPMS-versalab from Qantum Design. 2 Measurement samples were prepared using the configurations of the conductive paths in the modules involved in each embodiment and comparative example. Furthermore, a vibrating sample magnetometer (VSM) was used to sweep a magnetic field of ±800 [kA / m] parallel to the magnetization direction of the magnetized FeGa-containing fine wires. An MH curve was obtained at a temperature of 300K, taking into account the thickness of the FeGa-containing fine wires and the area of ​​the FeGa-containing fine wires in the measurement sample. The squareness ratio, Mr / Ms, was determined as the ratio of the magnetization Ms at ±800 [kA / m] to the magnetization Mr at 0 [kA / m] during the magnetic field sweep. The results are shown in Table 1.

[0101] [Measurement of internal stress]

[0102] Using the X-ray diffraction device Smartlab manufactured by Rigaku Corporation, Cu-Kα rays were irradiated onto the sample through a parallel beam optical system from a light source at 40 kV and 50 mA. 2 The principle of the Ψ method's tilting method was used to measure the first internal stress σ1 and second internal stress σ2 of the FeGa-containing fine wire in each Example and Comparative Example. The first internal stress σ1 is the internal stress in the longitudinal direction of the FeGa-containing fine wire, and the second internal stress σ2 is the internal stress in the width direction parallel to the main surface of the PET film and perpendicular to the longitudinal direction of the FeGa-containing fine wire. The wavelength λ of the Cu-Kα line is 0.1541 nm. sin 2The Ψ method is a method for determining the internal stress of a polycrystalline thin film from the dependence of the lattice strain of the thin film on the angle (Ψ). Using the above-mentioned X-ray diffraction apparatus, the diffraction intensity is measured at intervals of 0.01° within the range of 2θ = 75° to 85° by θ / 2θ scanning. The accumulation time at each measurement point is set to 100 seconds. The interplanar spacing d of the magnetic body at each measurement angle (Ψ) is calculated from the peak angle 2θ of the obtained X-ray diffraction and the wavelength λ of the X-ray irradiated from the light source. Based on the relationship between the following formulas (4) and (5), the lattice strain ε is calculated from the interplanar spacing d. λ is the wavelength of the X-ray (Cu-Kα line) irradiated from the light source, λ = 0.1541nm. d0 is the interplanar spacing of the crystal in a stress-free state, d0 = 0.0206nm.

[0103] 2dsinθ=λ Formula (4)

[0104] ε=(d-d0) / d0 Formula (5)

[0105] like Figure 7 As shown in FIG, the above X-ray diffraction measurement is performed when the angle (Ψ) formed between the normal line of the principal surface of the sample Sa and the normal line of the crystal plane of the crystal Mb is 0°, 17°, 24°, 30°, 35°, 40° and 45°, and the lattice strain ε at each angle (Ψ) is calculated. Then, according to the following formula (6), by substituting sin 2 The first internal stress σ1 and the second internal stress σ2 were calculated from the slope of the straight line plotting the relationship between Ψ and lattice strain ε. The results are shown in Table 1. Note that in the internal stresses in Table 1, positive values ​​indicate tensile stress, and negative values ​​indicate compressive stress. Since the tilt method measures stress in a direction 90° relative to the beam direction, when calculating the first internal stress σ1 and the second internal stress σ2, the sample was set up so that the measurement direction was perpendicular to the beam direction and the measurement was performed.

[0106] ε={(1+ν) / E}σsin 2 Ψ-(2ν / E)σ Formula (6)

[0107] In the above formula (6), E is the Young's modulus of the magnetic body (130 GPa), and ν is the Poisson's ratio of the magnetic body (0.3). Figure 7 The detector D in the detector detects the X-ray diffraction.

[0108] As shown in Table 1, the squareness ratios Mr / Ms of the conductive paths a, b, and c in Examples 1 and 2 are all high, indicating that the magnetic properties of the FeGa-containing fine wires in conductive paths a, b, and c have little variation. On the other hand, while the squareness ratio Mr / Ms of conductive path α in Comparative Example 1 is high, the squareness ratio of conductive path β is low. Therefore, the magnetic properties of the FeGa-containing fine wires in conductive paths α and β in the module of Comparative Example 1 have large variations. A comparison between Examples 1 and 2 shows that the width of the substrate in conductive path c in Example 2 is larger, indicating that the width of the PET film also needs to be increased. Therefore, it can be understood that, as in Example 1, when the lengths of the FeGa-containing fine wires in conductive path c vary, module miniaturization is facilitated.

[0109] [Table 1]

[0110]

[0111] A first aspect of the present invention provides a module comprising:

[0112] a first heat flow detection portion disposed on the substrate and comprising a first thermoelectric conversion portion forming a plurality of first thin wires and a first connection portion electrically connecting the first thin wires to each other; and

[0113] a second heat flow detection portion, which is disposed on the substrate and includes a second thermoelectric conversion portion forming a plurality of second thin wires and a second connection portion electrically connecting the second thin wires to each other;

[0114] The plurality of first thin lines and the plurality of second thin lines extend parallel to each other.

[0115] The second aspect of the present invention provides the module according to the first aspect, wherein:

[0116] The second thermoelectric conversion portion includes the second thin wires having different lengths.

[0117] The third aspect of the present invention provides the module according to the first aspect or the second aspect, wherein:

[0118] The substrate has a pair of end lines that overlap due to parallel movement in a plan view.

[0119] A fourth aspect of the present invention provides the module according to any one of the first to third aspects, wherein:

[0120] The first thermoelectric conversion portion generates an electromotive force in the longitudinal direction of the first thin wire by utilizing heat flow in a direction perpendicular to the surface of the substrate.

[0121] The second thermoelectric conversion portion generates an electromotive force in the longitudinal direction of the second thin wire by utilizing heat flow in a direction perpendicular to the surface of the substrate.

[0122] A fifth aspect of the present invention provides the module according to any one of the first to fourth aspects, wherein:

[0123] The first thin wire includes a magnetic body having an easy magnetization axis in a width direction perpendicular to the longitudinal direction of the first thin wire and extending along the surface of the substrate.

[0124] The second thin wire includes a magnetic body having an easy magnetization axis in a width direction perpendicular to the longitudinal direction of the second thin wire and extending along the surface of the substrate.

[0125] A sixth aspect of the present invention provides the module according to any one of the first to fifth aspects, wherein:

[0126] The difference obtained by subtracting the first internal stress of the first thin wire from the second internal stress of the first thin wire is 50 MPa or more.

[0127] The difference obtained by subtracting the first internal stress of the second thin wire from the second internal stress of the second thin wire is 50 MPa or more.

[0128] The first internal stress is the internal stress of the first thin line or the second thin line in a first direction parallel to the surface of the substrate.

[0129] The second internal stress is an internal stress of the first thin line or the second thin line in a second direction parallel to the surface of the substrate and perpendicular to the first direction.

[0130] A seventh aspect of the present invention provides the module according to any one of the first to sixth aspects, wherein:

[0131] The first heat flow detection portion forms a zigzag pattern.

[0132] The second heat flow detection portion forms a zigzag pattern.

[0133] An eighth aspect of the present invention provides a heat flow sensor,

[0134] The device includes the module according to any one of the first to seventh aspects.

Claims

1. A module having: a first heat flow detection portion disposed on the substrate and including a first thermoelectric conversion portion forming a plurality of first thin wires and a first connection portion electrically connecting the first thin wires to each other; and a second heat flow detection portion, which is disposed on the substrate and includes a second thermoelectric conversion portion forming a plurality of second thin wires and a second connection portion electrically connecting the second thin wires to each other; The plurality of first thin lines and the plurality of second thin lines extend parallel to each other.

2. The module according to claim 1, wherein: The second thermoelectric conversion portion includes the second thin wires having different lengths.

3. The module according to claim 1, wherein: The substrate has a pair of end lines that overlap due to parallel movement in a plan view.

4. The module according to claim 1, wherein: The first thermoelectric conversion portion generates an electromotive force in the longitudinal direction of the first thin wire by utilizing heat flow in a direction perpendicular to the surface of the substrate. The second thermoelectric conversion portion generates an electromotive force in the longitudinal direction of the second thin wire using a heat flow in a direction perpendicular to the surface of the substrate.

5. The module according to claim 1, wherein: The first thin wire includes a magnetic body having an easy magnetization axis in a width direction perpendicular to the length direction of the first thin wire and extending along the surface of the substrate. The second thin wire includes a magnetic body having an easy magnetization axis in a width direction perpendicular to the longitudinal direction of the second thin wire and extending along the surface of the substrate.

6. The module according to claim 1, wherein: The difference obtained by subtracting the first internal stress of the first thin wire from the second internal stress of the first thin wire is 50 MPa or more, The difference obtained by subtracting the first internal stress of the second fine wire from the second internal stress of the second fine wire is 50 MPa or more. The first internal stress is the internal stress of the first thin line or the second thin line in a first direction parallel to the surface of the substrate, The second internal stress is an internal stress of the first thin line or the second thin line in a second direction that is parallel to the surface of the substrate and perpendicular to the first direction.

7. The module according to claim 1, wherein: The first heat flow detection portion forms a zigzag pattern, The second heat flow detection portion forms a zigzag pattern.

8. A thermal flow sensor comprising the module according to any one of claims 1 to 7.

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