Temperature sensor and temperature sensor array

Abstract

The present invention relates to a temperature sensor and a temperature sensor array. The present invention provides a temperature sensor having excellent load resistance and capable of obtaining high temperature detection accuracy. The temperature sensor has a sensor portion formed on a flexible substrate, the flexible substrate including: a first portion located at an end portion of the flexible substrate and provided with the sensor portion; and a second portion adjacent to the first portion in a direction from the end portion toward a distal position and having a maximum thickness between a first surface and a second surface facing each other. The surface of the first portion opposite to the sensor portion and the first surface of the second portion are located on the same surface. At least the first surface of the second portion forms a detection surface in contact with a temperature detection object. The total thickness of the first portion and the sensor portion is smaller than the maximum thickness of the second portion.

Description

Technical Field

[0001] The present invention relates to a temperature sensor and a temperature sensor array comprising a plurality of temperature sensors. Background Art

[0002] Conventionally, a temperature sensor having a sensor portion formed on a flexible substrate is known. This temperature sensor can be configured to be flexible and thin as a whole, and is used for various applications for detecting the temperature of a temperature target object.

[0003] For example, Patent Document 1 discloses a temperature sensor in which an opening is provided in a flexible substrate, a flexible thermistor is embedded in the opening as a sensor portion, and the height of the surface around the opening of the flexible substrate is substantially the same as the height of the exposed surface of the flexible thermistor. Figure 5 A flexible thermistor having a metal substrate, a thermistor layer, and a pair of split electrodes is embedded in an opening of a flexible substrate having a base layer, a wiring conductor layer, and a cover layer, and is mounted on the wiring conductor layer via a solder layer so that the height of the surface of the cover layer is substantially the same as the height of the exposed surface of the flexible thermistor.

[0004] In addition, for example, Patent Document 2 discloses a temperature sensor in which a thin film thermistor portion and a pair of comb-shaped electrodes are provided as a sensor portion on the surface of an insulating film as a flexible substrate, and at least a portion of the insulating film directly below the thin film thermistor portion is formed to be thinner than other portions of the insulating film. Figure 1 A thin film thermistor portion and a pair of comb-shaped electrodes are provided on the surface of the insulating film, which are covered with a protective film, and a recess is provided in the insulating film directly below the thin film thermistor portion.

[0005] Patent Document 1: International Publication No. 2012 / 093572

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-90262

[0007] Patent Document 3: International Publication No. 2019 / 009320

[0008] A temperature sensor having a sensor portion formed on a flexible substrate is capable of being loaded in the thickness direction thereof. In order to achieve high temperature detection accuracy, it is preferable to make the temperature sensor fully contact the object to be detected with a certain degree of force. However, if a load is applied to the sensor portion of the temperature sensor, the stress generated in the sensor portion (more specifically, the thermistor layer) may cause a change in resistance due to deformation of the sensor portion, or deterioration due to cracks in the sensor portion, which may in turn lead to a reduction in temperature detection accuracy. In this situation, a temperature sensor with excellent load resistance and high temperature detection accuracy is required.

[0009] In the temperature sensor disclosed in Patent Document 1, since the height of the surface around the opening of the flexible substrate is substantially the same as the height of the exposed surface of the flexible thermistor, when a load is applied to the temperature sensor in the thickness direction, more specifically, as shown in Patent Document 1, Figure 7 As shown, when the temperature sensor is brought into contact with and pressed against an object to be detected, the load (pressing force) is uniformly applied to the entire contact area between the temperature sensor and the object to be detected (the total area of ​​the exposed surface of the flexible thermistor and the surrounding contact area of ​​the flexible substrate), thereby avoiding application solely to the exposed surface of the flexible thermistor. However, since the load is applied to the flexible thermistor (particularly the thermistor layer) based on the ratio of the area of ​​the exposed surface of the flexible thermistor to the overall area of ​​the contact area, stress in the thermistor layer cannot be eliminated, and sufficient load resistance may not be achieved. Resistance changes due to deformation of the thermistor layer and degradation due to cracks in the thermistor layer may occur, making it difficult to achieve high temperature detection accuracy. If only focusing on improving load resistance is considered, the area of ​​the contact area of ​​other parts should be made considerably larger relative to the area of ​​the exposed surface of the flexible thermistor. However, in this case, the contact area of ​​other parts becomes too large, and the heat of the temperature detection object (heat source) is lost through other parts to the wiring or the surface opposite to the contact surface, and high temperature detection accuracy cannot be obtained.

[0010] Furthermore, in the temperature sensor disclosed in Patent Document 2, since at least a portion directly below the thin film thermistor portion of the insulating film is formed thinner than the rest of the insulating film (provided with a recessed portion), when a load is applied to the temperature sensor in the thickness direction, more specifically, when the temperature sensor (the thin film thermistor portion side) is brought into contact with and pressed against an object to be detected, the load (pressing force) can be prevented from being directly applied to the thin film thermistor portion in the thickness direction. However, since the load acts on the thin film thermistor portion in a direction parallel to the in-plane direction of the insulating film (particularly when the protective film covers the upper surface and entire circumference of the thin film thermistor portion and the pair of comb-shaped electrodes, it acts significantly in the horizontal direction), stress in the thin film thermistor portion cannot be eliminated, and sufficient load resistance may not be achieved. Resistance changes due to deformation of the thin film thermistor portion and degradation due to cracks in the thin film thermistor portion may occur, making it difficult to achieve high temperature detection accuracy. Furthermore, the heat of the object to be detected (heat source) may be conducted through the entire temperature sensor and lost, making it impossible to obtain high temperature detection accuracy. Summary of the Invention

[0011] An object of the present invention is to provide a temperature sensor having excellent load resistance and capable of achieving high temperature detection accuracy. Another object of the present invention is to provide a temperature sensor array including a plurality of such temperature sensors.

[0012] According to one aspect of the present invention, there is provided a temperature sensor including a sensor portion formed on a flexible substrate.

[0013] The flexible substrate includes: a first portion located at an end portion of the flexible substrate and having the sensor portion formed therein; and a second portion adjacent to the first portion in a direction distal from the end portion and having a maximum thickness between the first and second surfaces facing each other.

[0014] The surface of the first portion opposite to the sensor portion and the first surface of the second portion are located on the same plane.

[0015] At least the first surface of the second portion forms a detection surface in contact with the object to be detected.

[0016] A total thickness of the first portion and the sensor portion is smaller than the maximum thickness of the second portion.

[0017] According to another aspect of the present invention, a temperature sensor array is provided. The temperature sensor array includes a plurality of the temperature sensors described above. The plurality of temperature sensors are connected to a common connection portion at or near an end portion of the flexible substrate opposite to the first portion.

[0018] According to the present invention, a temperature sensor having excellent load resistance and capable of achieving high temperature detection accuracy is provided. In addition, according to the present invention, a temperature sensor array including a plurality of such temperature sensors is provided, which can achieve the same effects as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic cross-sectional view of a temperature sensor according to one embodiment of the present invention.

[0020] Figure 2 It is an explanation Figure 1 A schematic cross-sectional view showing a schematic diagram of a usage of a temperature sensor according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic cross-sectional view of a temperature sensor according to another embodiment of the present invention.

[0022] Figure 4 It is an explanation Figure 2 A schematic cross-sectional view showing a schematic diagram of a usage of a temperature sensor according to an embodiment of the present invention.

[0023] Figure 5 It is an explanation Figure 2 A schematic cross-sectional view showing a usage of a modified example of the temperature sensor according to the embodiment of the present invention.

[0024] Figure 6 (a) is a description of Figure 1 A schematic cross-sectional view showing a usage example of a temperature sensor according to a modified embodiment of the present invention. Figure 6 (b) is a description of Figure 2 A schematic cross-sectional view showing a usage of a modified example of the temperature sensor according to the embodiment of the present invention.

[0025] Figure 7 This is a schematic cross-sectional view of a temperature sensor according to another embodiment of the present invention.

[0026] Figure 8 Yes Figure 7 1 is a diagram showing a specific example of a temperature sensor according to an embodiment of the present invention, wherein (a) is a schematic cross-sectional view taken at a ZZ section of (b), and (b) is a schematic plan view showing the internal structure in a transparent manner.

[0027] Figure 9 Yes Figure 7 1 and 2. FIG. 1 is a diagram showing another specific example of a temperature sensor according to an embodiment of the present invention, wherein (a) is a schematic cross-sectional view taken at a ZZ section of (b), and (b) is a schematic plan view showing the internal structure in a transparent manner.

[0028] Figure 10Yes Figure 7 Figure 1 is a diagram showing another specific example of a temperature sensor according to an embodiment of the present invention, wherein (a) is a schematic cross-sectional view at the ZZ section of (b), (b) is a schematic top view showing the internal structure in a transparent manner, and (c) is a schematic top view showing only the electrodes and the lead-out electrode portion.

[0029] Figure 11 Yes Figure 7 Figure 1 is a diagram showing another specific example of a temperature sensor according to an embodiment of the present invention, wherein (a) is a schematic cross-sectional view at the ZZ section of (b), (b) is a schematic top view showing the internal structure in a transparent manner, and (c) is a schematic top view showing only the electrodes and the lead-out electrode portion.

[0030] Figure 12 This is a schematic plan view of a temperature sensor array according to one embodiment of the present invention, and shows the internal structure excluding the sensor portion and the first portion in a transparent manner.

[0031] Figure 13 It is an explanation Figure 12 A schematic perspective view of a usage mode of the temperature sensor array according to the embodiment is a view showing a part of the internal structure in a transparent manner.

[0032] Figure 14 (a) is a schematic plan view showing the pattern of the comb-shaped electrodes and the extraction electrode portion in the temperature sensor array produced in Comparative Example 1. Figure 14 (b) is a schematic top view of the temperature sensor array produced in Comparative Example 1.

[0033] Figure 15 (a) is a graph showing the results of the load test of Comparative Example 1, Figure 15 (b) is a graph showing the results of the load test of Example 1.

[0034] Figure 16 (a) is a schematic plan view showing the pattern of the comb-shaped electrodes and the extraction electrode portion in the temperature sensor array produced in Comparative Example 2. Figure 16 (b) is a schematic top view of the temperature sensor array produced in Comparative Example 2.

[0035] Figure 17 (a) is a schematic plan view showing the pattern of the comb-shaped electrodes and the extraction electrode portion in the temperature sensor array produced in Example 1. Figure 17 (b) is a schematic top view of the temperature sensor array produced in Example 1.

[0036] Figure 18The results show that in the test of Example 2, when the thickness t of the opposing object (metal plate), the total thickness d1 of the first part and the sensor part, the maximum thickness d2 of the second part, and the thickness ratio d1 / d2 were variously changed, the L at which no load of 10 MPa or more was applied to the sensor part was investigated. 1MAX The graph of the results is shown in Figure 2. (a) shows the L when d1 = 0.06 mm and d1 / d2 = 0.5 or 0.83. 1MAX The graph of the relationship between L and t, (b) shows L when t = 2.0 mm and d1 = 0.06 mm. 1MAX The graph of the relationship between L and d1 / d2, (c) shows L when t = 2.0 mm and d1 / d2 = 0.5 or 0.83. 1MAX A graph showing its relationship to d1.

[0037] Figure 19 (a) is a schematic plan view showing the pattern of the comb-shaped electrodes and the extraction electrode portion in the temperature sensor array produced in Example 3. Figure 19 (b) is a schematic top view of the thermistor element produced in Example 3. DETAILED DESCRIPTION

[0038] Hereinafter, the present invention will be described in detail using a plurality of embodiments with reference to the drawings, but the present invention is not limited to these embodiments.

[0039] (Implementation Method 1)

[0040] This embodiment relates to a temperature sensor including a sensor portion formed on a flexible substrate.

[0041] Reference Figure 1 In the temperature sensor 30 of this embodiment, the flexible substrate 20 includes a first portion 11 located at one end X of the flexible substrate 20 and having the sensor portion 10 formed thereon; and a second portion 12 adjacent to the first portion 11 in a distal direction from the end X and having a maximum thickness d2 between the opposing first surface A2 and second surface B2. In the present invention, "maximum thickness" refers to the maximum thickness of the entire temperature sensor. "Adjacent to the distal direction from the end X" of the second portion relative to the first portion means that the second portion is adjacent to the first portion in a direction from the end X on one side of the first portion toward the end Y on the other side. In other words, the second portion having the maximum thickness d2 does not exist in directions other than the distal direction relative to the first portion.

[0042] In the temperature sensor 30 of this embodiment, the sensor portion 10 is formed on the first portion 11, and the surface A1 of the first portion 11 opposite the sensor portion 10 and the first surface A2 of the second portion 12 are coplanar. In the present invention, "two surfaces coplanar" means that they form a common plane when no load (or external force) is applied to the temperature sensor. However, this is not limited to the case when a load is applied, and the sensor may also bend and / or flex, for example.

[0043] In the temperature sensor 30 of this embodiment, the combined thickness d1 of the first portion 11 and the sensor unit 10 is less than the maximum thickness d2 of the second portion 12. The ratio of d1 to d2 (thickness ratio d1 / d2) is preferably 0.83 (approximately 5 / 6) or less. The lower limit is not particularly limited, but may be, for example, 0.1 (1 / 10) or greater. The combined thickness d1 of the first portion 11 and the sensor unit 10 is the thickness dimension between surface A1 of the first portion 11 and the exposed surface B1 of the sensor unit 10 facing the surface A1.

[0044] As long as the sensor portion 10 has the function of detecting temperature, it is not particularly limited. For example, it may include a thermistor layer and two electrodes that are in contact with the thermistor layer and are configured separately from each other. In addition, it may include or not include a covering layer (or protective film). The thermistor layer and the two electrodes can be made of any appropriate material and can be of any appropriate structure and configuration. The thermistor layer can, for example, utilize the materials disclosed in Patent Document 3. The electrodes can, for example, be a pair of comb-shaped electrodes formed in contact with the thermistor layer, or a pair of split electrodes configured in contact with the thermistor layer (and preferably opposite to the non-connected internal electrode), or a pair of planar electrodes that clamp the thermistor layer. The first portion 11 and the second portion 12 can appropriately include two lead-out electrode portions drawn from the two electrodes of the sensor portion 10 and two wirings electrically connected to them respectively. The electrodes and the lead-out electrode portions can also be formed separately, but are preferably formed integrally. In addition, the number of thermistor layers, electrodes, lead-out electrode portions, and wirings can also be greater.

[0045] The temperature sensor 30 of this embodiment can be configured to be flexible and thin overall. The material and thickness of the flexible substrate 20, which bears the flexibilities, can be appropriately selected, but the maximum thickness d2 is preferably 200 μm or less, more preferably 100 μm or less. The lower limit is not particularly limited, and can be, for example, 60 μm or more.

[0046] In the temperature sensor 30 of this embodiment, the sensor portion 10 is positioned close to the second portion 12. Therefore, the length L1 of the first portion 11 (the dimension between one end X of the flexible substrate 20 (the end surface in the illustrated embodiment) and the boundary between the first and second portions 11 and 12) is preferably small, for example, 30 mm or less, particularly 20 mm or less, and more preferably 10 mm or less. Depending on the situation, it can be 5 mm or less, with no particular lower limit, for example, 1 mm or greater. While not limiting this embodiment, when d1 / d2 is 0.83 or less, L1 can be 9.5 mm or less. Meanwhile, the length L2 of the second portion 12 (the dimension between the boundary between the first and second portions 11 and 12 and the other end Y of the flexible substrate 20 (the end surface in the illustrated embodiment) in this embodiment) is not particularly limited and can vary depending on the intended use of the temperature sensor 30.

[0047] like Figure 2 As shown, the temperature sensor 30 of the present embodiment described above is used so that at least the first surface A2 of the second portion 12 is in contact with the temperature detection object 41. In other words, at least the first surface A2 of the second portion 12 forms a detection surface that is in contact with the temperature detection object 41 (in more detail, pressed against and in close contact with the temperature detection object 41). The surface A1 of the first portion 11 on the opposite side to the sensor portion 10 may also be in contact with the temperature detection object 41 (capable of forming a detection surface), but the surface A1 may not necessarily be in contact with the temperature detection object 41, and may, for example, "float" from the temperature detection object 41. In particular, as Figure 2 As shown, the temperature sensor 30 can be used in a state where it is pressed between the temperature detection object 41 and the opposing object 43. The second surface B2 of the second portion 12 can be in contact with the opposing object 43. The opposing object 43 is not particularly limited and can be, for example, a metal plate.

[0048] When the temperature sensor 30 is in use, a load (pressing force) is applied to it in the thickness direction. According to the temperature sensor 30 of this embodiment, since the second portion 12, which does not form the sensor unit 10, has a maximum thickness d2, when a load is applied in the thickness direction of the temperature sensor 30, the load is applied to the second portion 12, and the load is not directly applied to the sensor unit 10 formed in the first portion 11. Furthermore, the application of the load to the second portion 12 can propagate stress to the first portion 11 adjacent to the second portion 12. However, since the first portion 11 is located at the end X of the flexible substrate 20 and is free, the stress can be effectively alleviated. As a result, the generation of stress in the sensor unit 10 can be substantially eliminated, achieving excellent load-bearing performance. Furthermore, according to the temperature sensor 30 of this embodiment, a decrease in temperature detection accuracy caused by the generation of stress in the sensor unit 10 can be prevented. Furthermore, according to the temperature sensor 30 of this embodiment, the first surface A2 of the second portion 12 forms a detection surface that contacts the temperature detection object 41. The first surface A2 is pressed against and in close contact with the temperature detection object 41 by a load (pressing force). Furthermore, the sensor portion 10 is formed in the first portion 11 adjacent to the second portion 12. Therefore, the temperature of the temperature detection object 41 can be detected with high accuracy by the sensor portion 10. In other words, according to this embodiment, a temperature sensor 30 having excellent load resistance and capable of achieving high temperature detection accuracy can be provided.

[0049] (Implementation Method 2)

[0050] This embodiment relates to a modified example of the temperature sensor of the first embodiment, and unless otherwise specified, the same description as that of the first embodiment is applicable.

[0051] Reference Figure 3 In the temperature sensor 30' of this embodiment, the flexible substrate 20' includes a first portion 11 located at one end X of the flexible substrate 20' and having the sensor portion 10 formed thereon; a second portion 12' adjacent to the first portion 11 in the distal direction from the end X and having a maximum thickness d2 between a first surface A2' and a second surface B2' facing each other; and a third portion 13 adjacent to the second portion 12' in the distal direction from the end X and having a thickness d3, which is less than the maximum thickness d2, between a third surface A3 and a fourth surface B3 facing each other. The first portion 11, the second portion 12', and the third portion 13 may also include, as appropriate, two lead-out electrodes extending from the two electrodes of the sensor portion 10 and two wirings electrically connected thereto.

[0052] In the temperature sensor 30' of this embodiment, the fourth surface B3 of the third portion 13 and the second surface B2' of the second portion 12' are coplanar. Therefore, because the thickness d3 of the third portion 13 is smaller than the maximum thickness d2 of the second portion 12', the third surface A3 of the third portion 13 is positioned inward relative to the first surface A2' of the second portion 12'. The flexible substrate 20' can be understood as a substrate having a generally S-shaped cross-section, comprised of the first portion 11, the second portion 12', and the third portion 13.

[0053] In the temperature sensor 30' of this embodiment, the length L2' of the second portion 12' (in this embodiment, the dimension between the boundary between the first portion 11 and the second portion 12' and the boundary between the second portion 12' and the third portion 13) can be appropriately selected to provide a minimum area required for a detection surface, as described later, while also achieving higher temperature detection accuracy. Meanwhile, the length L3 of the third portion 13 (the dimension between the boundary between the second portion 12' and the third portion 13 and the other end Y of the flexible substrate 20') is not particularly limited and may vary depending on the intended use of the temperature sensor 30'.

[0054] like Figure 4 As shown, the temperature sensor 30' of the present embodiment described above is used so that at least the first surface A2' of the second part 12' is in contact with the temperature detection object 41. In other words, at least the first surface A2' of the second part 12' forms a detection surface that is in contact with the temperature detection object 41 (in more detail, pressed against and in close contact with the temperature detection object 41). The surface A1 of the first part 11 on the opposite side to the sensor part 10 may also be in contact with the temperature detection object 41 (can form a detection surface), but the surface A1 may not necessarily be in contact with the temperature detection object 41, for example, it may also "float" from the temperature detection object 41. The third surface A3 of the third part 13 is separated from (not in contact with) the temperature detection object 41, but for example, when the third part 13 is bent, the third surface A3 may be partially in contact with the temperature detection object 41. In particular, as Figure 4 As shown, the temperature sensor 30' can be used while being pressed between the temperature detection object 41 and an opposing object 43. In addition to the second surface B2' of the second portion 12', the fourth surface B3 of the third portion 13 can also contact the opposing object 43.

[0055] When the temperature sensor 30' is in use, a load (pressing force) is applied to the temperature sensor 30' in the thickness direction thereof. According to the temperature sensor 30' of this embodiment, since the first surface A2' pressed against and in close contact with the temperature detection object 41 due to the load (pressing force) is smaller than the first surface A2 of the temperature sensor 30 in the first embodiment, the heat of the temperature detection object 41 (heat source) is not easily transferred to the second surface B2' and the fourth surface B3 (and the opposing object 43), etc., and can be more effectively transferred to the sensor 10, and the temperature of the temperature detection object 41 can be detected with higher accuracy by the sensor unit 10. That is, according to this embodiment, in addition to the same effects as the first embodiment, a temperature sensor 30' is provided that can achieve higher temperature detection accuracy.

[0056] To achieve higher temperature detection accuracy, the area of ​​first surface A2' is preferably less than 3% of the measured area of ​​temperature detection object 41. By preventing heat from temperature detection object 41 (heat source) from being transferred to second surface B2' and fourth surface B3 (and opposing object 43), temperature detection can be performed with an accuracy within ±0.5°C relative to the actual temperature of temperature detection object 41.

[0057] In order to further improve the accuracy of temperature detection, it is preferable to adjust the thermal insulation and heat dissipation properties of the temperature sensor 30' according to the object to be detected 41 (heat source). If the heat source of the object to be detected 41 is small, by minimizing heat conduction (ensuring heat insulation), the temperature change of the object to be detected 41 caused by inserting the temperature sensor 30' between the object to be detected 41 and the opposing object 43 can be reduced, and the temperature detection accuracy can be further improved. If the heat source of the object to be detected 41 is large, by improving heat conduction (ensuring heat dissipation), the temperature change of the object to be detected 41 caused by inserting the temperature sensor 30' between the object to be detected 41 and the opposing object 43 can be reduced, and the temperature detection accuracy can be further improved.

[0058] In cases where thermal insulation is required, such as Figures 3-4 As shown in the temperature sensor 30', the third surface A3 of the third portion 13 can be exposed. This allows air (or other gas depending on the situation) to be introduced into the gap between the temperature detection object 41 and the third surface A3 for thermal insulation.

[0059] Or, where thermal insulation is required, e.g. Figure 5As shown, the third surface A3 of the third portion 13 can also be covered with a thermal insulating material 15 in contact with the temperature detection object 41. This allows the thermal insulating material 15 to fill the gap between the temperature detection object 41 and the third surface A3, providing thermal insulation. If the impact on the sensor unit 10 is tolerable, the gap between the sensor unit 10 and the opposing object 43 can also be filled with the thermal insulating material 15' to provide further thermal insulation. Furthermore, the thermal insulating material can be any material with a low thermal conductivity, for example, a material with a thermal conductivity of 1 W / (m·K) or less.

[0060] In the case of requiring heat dissipation (cooling), such as Figure 5 As shown, the third surface A3 of the third portion 13 can be covered with a heat dissipation material 15 in contact with the temperature detection object 41. This allows the heat dissipation material 15 to fill the gap between the temperature detection object 41 and the third surface A3, dissipating heat. If the impact on the sensor unit 10 is acceptable, the gap between the sensor unit 10 and the opposing object 43 can also be filled with the heat dissipation material 15', further dissipating heat. Furthermore, the heat dissipation material can be any material with a high thermal conductivity, for example, a material with a thermal conductivity of 10 W / (m·K) or higher.

[0061] Alternatively, if heat dissipation (cooling) is required, Figure 6 As shown in (a) to (b), the load (pressing force) can also be increased to deform the opposing object 43 and / or the temperature detection object 41, so that the opposing object 43 (such as a metal plate) contacts the temperature detection object 41 ( Figure 6 (a) shows the case of the temperature sensor 30 in the first embodiment. Figure 6 (b) shows the case of the temperature sensor 30' of embodiment 2). The contact area between the opposing object 43 and the temperature detection object 41 can also be appropriately adjusted. As a result, the heat of the temperature detection object 41 can be released to the opposing object 43, resulting in heat dissipation (cooling). In this case, by appropriately selecting the thickness t of the opposing object 43, the maximum thickness d2 of the second portion 12 or 12', and the length L1 of the first portion 11, it is possible to prevent a load from being applied to the sensor portion 10 (for example, deformation of the opposing object 43, directly applying a load to the sensor portion 10).

[0062] In either case, the temperature change of the object to be detected 41 caused by inserting the temperature sensor 30 ′ between the object to be detected 41 and the opposing object 43 can be suppressed to ±0.5° C. or less.

[0063] (Implementation 3)

[0064] This embodiment relates to a specific example of the temperature sensor of the second embodiment, and unless otherwise specified, the same description as that of the first and second embodiments can be applied.

[0065] Reference Figure 7 In the flexible substrate 20" of the temperature sensor 30" of this embodiment, the second portion 12" includes a first portion expansion portion 12a from the first portion 11, a third portion expansion portion 12b from the third portion 13, and a joining portion 12c joining these expansion portions 12a and 12b.

[0066] For more details, refer to Figures 8-11 The sensor portion 10 includes a thermistor layer 1 and two electrodes 3 that are in contact with the thermistor layer 1 and are separated from each other, and may include or exclude a covering layer (or protective film) 7. Figure 8 and Figure 9 In the embodiment, the two electrodes 3 are a pair of comb-shaped electrodes formed in contact with the thermistor layer 1. Figure 10 and Figure 11 In the embodiment, the two electrodes 3 are a pair of split electrodes that are in contact with the thermistor layer 1 and are arranged opposite to the non-connected internal electrode 3'. Figure 10 and Figure 11 In the embodiment, the electrode 3 and the lead electrode portion 5 are formed integrally. It is difficult to clearly define the boundary between the electrode 3 and the lead electrode portion 5. However, the electrode 3 only needs to include the area facing the non-connection type internal electrode 3'. For convenience, Figure 10 (c) and Figure 11 In (c), the above boundary is indicated by a dotted line. Figures 8-11 In the figure, the first part 11, the second part 12", the first part expansion part 12a, the third part expansion part 12b, the third part 13, etc. are omitted, but the reference numerals of the first part 11, the second part 12", the first part expansion part 12a, the third part expansion part 12b, the third part 13, etc. are omitted. Figure 7 By comparison, it can be understood that the reference numerals of these omitted parts refer to Figures 8-11 Also, please note that Figures 9-10 In the embodiment, a portion of the thermistor layer 1 exists in the first portion extension 12 extending to the second portion 12″, but the portion of the thermistor layer 1 existing in the first portion extension 12a is not provided with the electrode 3 and therefore does not function as a sensor, and is therefore not included in the sensor portion 10.

[0067] Moreover, refer to Figures 7-11The first portion 11 and the first portion expansion portion 12a include a first substrate 21 and two lead electrode portions 5 formed on the first substrate 21 and extending from the two electrodes 3 of the sensor portion 10. The third portion 13 and the third portion expansion portion 12b include a second substrate 23 and two wirings 25 formed on the second substrate 23. Moreover, the two lead electrode portions 5 and the two wirings 25 are electrically connected to each other via the joint portion 12c. In the first portion 11, a covering layer 7 covering the thermistor layer 1 and / or the electrode 3 may also be provided. In addition, in the third portion 13, a covering layer 27 covering the wiring 25 may also be provided. Although not required in this embodiment, the covering layer 27 may be removed at the end Y of the third portion 13 and its vicinity to expose the wiring 25, and a reinforcing plate 29 may be provided on the surface of the second substrate 23 on the opposite side thereof, which can be connected to a connecting portion such as a connector (not shown). In this case, the connecting portion such as the connector and the joint portion 12c can be understood as a secondary connecting portion and a primary connecting portion, respectively.

[0068] The bonding portion 12c may be made of any suitable material and method, as long as it can electrically connect the two extraction electrodes 5 and the two wirings 25 (preferably thin and sufficiently electrically and strongly bonded). Examples of the bonding portion 12c include anisotropic conductive film (ACF), solder, conductive paste, sealing the contact portion with a curable resin (sealing the periphery of the extraction electrode and wiring with a curable resin while the lead electrode and wiring are in contact, and then the resin is cured to seal the connection), and ultrasonic bonding.

[0069] According to the present embodiment, the second portion 12 ″ collectively includes the lead electrode portion 5 and the wiring 25 and the joint portion 12 c joining them, thereby obtaining relatively high rigidity and further improving load bearing performance.

[0070] According to the temperature sensor 30 ″ of this embodiment, Figures 8-11 As shown, the temperature sensor 30' of the second embodiment can be easily concretized. The temperature sensor 30" of this embodiment can be manufactured by forming the sensor portion 10 in the first portion 11 and the first portion expansion portion 12a, separately preparing the third portion and the third portion expansion portion 12cb, and joining them using the joining portion 12c. Therefore, according to this embodiment, a temperature sensor 30" is provided. This temperature sensor 30" is a temperature sensor that has excellent load resistance and can obtain high temperature detection accuracy, and is suitable for mass production at low cost using a simple manufacturing method.

[0071] (Implementation 4)

[0072] This embodiment relates to a temperature sensor array including a plurality of temperature sensors according to the third embodiment, and unless otherwise specified, the same description as in the first to third embodiments is applicable.

[0073] Reference Figure 12 The temperature sensor array 40 of this embodiment includes a plurality of temperature sensors 30A to 30C, and the plurality of temperature sensors 30A to 30C are connected to a common connection portion 31 at or near the end Y on the opposite side of the flexible substrate to the first portion 11 (located at the end X). In this case, the common connection portion 31 and the joint portion 12c can be understood as a secondary connection portion and a primary connection portion, respectively. In the example shown in the figure, the end Y of the temperature sensors 30A to 30C is inserted into the common connection portion (such as a connector) 31, but is not limited to this. The plurality of temperature sensors 30A to 30C are separated from each other, and the plurality of temperature sensors 30A to 30C can be manufactured by cutting them separately after being manufactured simultaneously as a whole, and the cutting can be performed before or after the plurality of temperature sensors 30A to 30C are connected to the common connection portion 31.

[0074] In the illustrated embodiment, the temperature sensor array 40 is shown as including three temperature sensors 30A to 30C as the plurality of temperature sensors. However, the number of the plurality of temperature sensors is not particularly limited as long as it is two or more, and may be selected according to the application of the temperature sensor array 40. Furthermore, in this embodiment, the temperature sensor array 40 is shown as including a plurality of temperature sensors according to Embodiment 3, but any temperature sensor according to Embodiments 1 to 3 may be used.

[0075] According to the temperature sensor array 40 of this embodiment, the plurality of temperature sensors 30A-30C can be brought into contact with different temperature detection objects to detect respective temperatures. According to the temperature sensor array 40 of this embodiment, the plurality of temperature sensors 30A-30C are connected to a common connection portion 31. Therefore, simply by connecting the common connection portion 31 to an external device such as a measurement circuit (not shown), the plurality of temperature sensors 30A-30C can be connected to an external device at once.

[0076] The temperature sensor array 40 of this embodiment can be used for any appropriate purpose, for example, Figure 13 As shown, the plurality of battery cells (batteries) 51 of the lithium-ion battery module can be utilized by sandwiching one temperature sensor 30A to 30C between two adjacent battery cells 51, thereby detecting the temperature of each battery cell 51. Figure 13 In the embodiment, a temperature sensor array circuit substrate 55 is assembled on a battery module circuit substrate 53 of a battery pack loaded with a plurality of battery cells 51, and the temperature sensor array 40 is connected to the temperature sensor array circuit substrate 55 via a common connection portion (e.g., a connector) 31. Figure 12As shown, the end Y of the temperature sensor array 40 is inserted into the connection portion (connector) 31. Figure 13 In the embodiment, the temperature sensor array 40 is connected from the connection portion (connector) 31 toward Figure 13 The perspective view is temporarily drawn out in front and then bent, and is led along the back side of the battery module circuit substrate 53, but is not limited to Figure 13 In the illustrated embodiment, in a lithium-ion battery module 50, the sensor portions 10A to 10C of the temperature sensors 30A to 30C sandwiched between two adjacent battery cells 51 can be in a state where a load (pressure) is applied between the battery cells 51. Preferably, the sensor portions 10A to 10C can withstand the assumed load (pressure) in this state while exhibiting high temperature detection accuracy. The temperature sensor array 40 of this embodiment has excellent load-bearing performance and can achieve high temperature detection accuracy, making it suitable for detecting the temperature of each battery cell in a lithium-ion battery module.

[0077] Example

[0078] (Comparative Example 1)

[0079] Comparative Example 1 relates to a temperature sensor including a sensor portion and having a uniform thickness as a whole.

[0080] Manganese acetylacetonate is added to metal oxide particles containing Mn:Ni in a ratio of 4:1 (atomic ratio) and having an average particle size of about 0.2μm at a ratio of 10% by mass (relative to the total mass of the metal oxide particles), and a raw material mixture is prepared using ethanol as a solvent, and they are mixed for 16 hours. The raw material mixture in the form of a slurry obtained in this way is supplied to a copper foil with a thickness of 10μm in the form of a sheet with a thickness of 10μm by a doctor blade method. After drying the sheet at 100°C for 10 hours, a hot press is used to heat it at 250°C for 30 minutes under a pressure of 100MPa to obtain a precursor structure. The precursor structure is annealed at 250°C for 10 hours to remove unnecessary organic matter that may remain, thereby obtaining a structure. Then, a polyamide-imide precursor liquid is applied to the film (composite layer containing metal oxide that can function as a thermistor layer) derived from the above-mentioned sheet in the obtained structure with a thickness of 10 μm, and heated at 200°C for 1 hour to thermally cure the polyamide-imide to form a resin substrate. Then, a resist is applied to the surface of the copper foil on the opposite side of the resin substrate in a predetermined pattern, exposed and developed, and a predetermined portion of the copper foil is etched away. The remaining resist is removed, and a pattern is formed to form two comb-shaped electrodes and an extraction electrode portion extending from each comb-shaped electrode. The pattern of the copper foil is as follows: Figure 14As shown schematically in (a), the outer dimensions of the comb-teeth portion of the comb-shaped electrode 3 viewed from above are set to 1.5 mm in width and 3.0 mm in length, and the handle portion of the comb-teeth portion and the lead-out electrode portion 5 are respectively set to 0.5 mm in width and 150 mm in length on both sides in the width direction of the comb-teeth portion (the area of ​​the sensor portion is 3.0 mm in width and 3.0 mm in length, and the lead-out electrode portion is long enough, so it can also be understood as wiring). In addition, Figure 14 The comb electrode of (a) is a schematic illustration, and the details of the comb electrode (the size, number and spacing of each comb electrode) can be Figure 14 (a) is different (the same applies to the following comparative examples and examples). A polyimide tape (a polyimide film with an adhesive layer: about 30 μm thick) is attached as a covering layer (on the laminate having a patterned copper layer (comb-shaped electrode and lead electrode portion: about 10 μm thick) formed on the upper surface of the laminate having a resin substrate (thickness of about 10 μm) and a composite layer containing a metal oxide (thermistor layer: thickness of about 10 μm) thus obtained. Figure 14 (b) of FIG. 1 , the covered layer is represented by the hatched area) so as to cover the copper layer. The structure thus obtained is cut using a cutting saw, as shown in FIG. Figure 14 As shown in (a) to (b), a temperature sensor with a width of about 3 mm and a length of about 150 mm and a uniform thickness of 60 μm was produced.

[0081] The temperature sensor produced was subjected to a load test. More specifically, the temperature sensor was clamped between two iron plates with a diameter of 50 mm and a thickness of 25 mm, and a pressure of 0.5 tons (about 5000 N) was applied repeatedly 5 times to measure the change in resistance value (ΔR(-)) at the same temperature. In addition, when the pressure was applied, a pressure-sensitive film (manufactured by Fujifilm Corporation, "Prescale" for medium pressure, with a detection sensitivity of 10 MPa, the same below) was clamped between the comb-shaped electrode (corresponding to the sensor part) of the temperature sensor and the iron plate and the pressure was measured to confirm that a load of more than 10 MPa was applied to the sensor part. The results are as follows. Figure 15 As shown in (a). Figure 15 As shown in (a), it can be seen that the resistance change rate in the load test is 5% or more, and the error in temperature detection is larger than 5°C.

[0082] (Comparative Example 2)

[0083] Comparative Example 2 relates to a temperature sensor having uniform thickness throughout both outer portions in the longitudinal direction except for the sensor portion.

[0084] like Figure 16As shown in (a) to (b), a temperature sensor (at Figure 16 In (b), the shaded area represents the covering layer. In this temperature sensor, in addition to the sensor portion corresponding to the comb-shaped electrodes 3, the covering layer also covers the dummy portion D and the lead electrode portion 5. The thickness from the back surface of the resin substrate to the highest exposed surface of the comb-shaped electrodes 3 is 30 μm, while the thickness from the back surface of the resin substrate to the outer surface of the covering layer is 60 μm.

[0085] The temperature sensor produced was subjected to the same load test as in Comparative Example 1. Furthermore, when pressure was applied, the pressure-sensitive film was sandwiched between the comb-shaped electrode (corresponding to the sensor portion) of the temperature sensor and the iron plate, and the pressure was measured, confirming that a load of 10 MPa or more was applied to the sensor portion in Comparative Example 2 as well. As a result, it was found that the resistance change rate during the load test was 5% or more, and satisfactory temperature detection accuracy could not be obtained, making the temperature sensor unqualified. It is believed that in this temperature sensor, although a structure was adopted in which no load was directly applied to the sensor portion, the covering layer was deformed in the horizontal direction due to the load, and the horizontal stress was propagated to the thermistor layer, resulting in a change in resistance. As described above, the confirmation that a load of 10 MPa or more was applied to the sensor portion was considered to be due to the deformation of the sensor portion due to the application of stress in the horizontal direction, and the load was measured in the vertical direction.

[0086] (Example 1)

[0087] Example 1 involves reference Figures 1-2 The temperature sensor of the first embodiment described above.

[0088] In addition to using the cover layer cut by the length L1 from the end where the comb electrode exists, as shown in FIG. Figure 17 As shown in (a) to (b), the first portion of the length L1 from the above end is not covered (at Figure 17 A temperature sensor was produced in the same manner as in Comparative Example 1 (with a cover layer thickness of approximately 30 μm), except that the cover layer was covered (indicated by the shaded area in (b)). In this temperature sensor, the length L1 was set to 5.0 mm. The thickness from the back of the resin substrate to the highest exposed surface of the comb-shaped electrodes (the combined thickness d1 of the first portion and the sensor portion) was 30 μm. Conversely, the thickness from the back of the resin substrate to the outer surface of the cover layer (the maximum thickness d2 of the second portion) was 60 μm.

[0089] The temperature sensor was subjected to the same load test as in Comparative Example 1. Furthermore, when applying pressure, the pressure-sensitive film was sandwiched between the comb-shaped electrode (corresponding to the sensor portion) of the temperature sensor and the iron plate, and the pressure was measured to confirm that no load exceeding 10 MPa was applied to the sensor portion. Figure 15 As shown in (b). Figure 15 As shown in (b), the resistance change rate in the load test can be 1% or less, and the temperature detection error can be within 1°C.

[0090] (Example 2)

[0091] Example 2 involves reference Figures 1-2 The temperature sensor of the embodiment 1, in more detail, relates to Figure 6 (a) How to use it.

[0092] Temperature sensors were fabricated in the same manner as in Example 1, except that the thickness of the resin substrate, the location where the cover layer was attached, and the thickness of the cover layer (one or two or more sheets were laminated on the front side, or one or two or more sheets were laminated on the entire back side of the resin substrate, depending on the situation) were varied. Thus, the combined thickness d1 of the first portion and the sensor portion, the maximum thickness d2 of the second portion, and the length L1 of the first portion were varied.

[0093] A metal plate (60 mm square SUS plate) with a thickness of t is placed on the manufactured temperature sensor as a counter object ( Figure 6 (a), indicated by reference numeral 43), and then a 1mm thick fluororubber is arranged on the outside thereof, and they are clamped between the upper and lower plates of the punching machine and a pressure of 0.5 tons is applied. Figure 6 The load applied to the sensor portion by the deformation of the metal plate shown in (a). Different conditions are set for the thickness t of the metal plate, the total thickness d1 of the first portion and the sensor portion, the maximum thickness d2 of the second portion, and the thickness ratio d1 / d2. Then, when pressure is applied, the pressure-sensitive film is sandwiched between the entire surface of the temperature sensor and the metal plate in a covering manner and the pressure is measured. Under each condition, the maximum L1 (hereinafter referred to as "L 1MAX ”). The results are shown in Table 1 and Figure 18 As shown in (a) to (c).

[0094] [Table 1]

[0095]

[0096] Figure 18 (a) represents L when d1 = 0.06 mm and d1 / d2 = 0.5 or 0.83 1MAX The relationship between t and Figure 18 As can be understood from (a), when d1 = 0.06 mm, d1 / d2 = 0.5 and 0.83 (i.e., not affected by d1 / d2), L 1MAX The minimum value is shown at t = 2.0 mm. This can be understood as follows. Figure 2 As shown, assuming that a metal plate with a sufficiently large thickness t is used as the opposing object (in Figure 2 In the case of the metal plate, which is indicated by reference numeral 43, even if pressure is applied to the metal plate, the metal plate does not substantially deform, and all the pressure is applied to the second portion (the portion with thickness d2). No matter how L1 is increased, a load of more than 10 MPa will not be applied to the sensor portion. Theoretically, L 1MAX Infinite. As the thickness t of the metal plate decreases, the metal plate is easily deformed. Figure 2 The schematically represented state moves to Figure 6 (a) schematically shows the state. In addition, the degree of deformation of the metal plate may depend on the pressure (load) and the material properties of the metal in addition to the thickness t of the metal plate. However, under the conditions of Example 2 (and the use assumed in Example 2 described later), it is not greatly affected by these factors, so only the influence of the thickness t is considered. It is easy to understand that as the thickness t of the metal plate decreases, the deformation of the metal plate gradually increases, and the load applied to the sensor portion becomes more than 10 MPa, and L appears. 1MAX As the load applied to the sensor increases, L 1MAX The value of gradually decreases. Moreover, when the thickness t of the metal plate is further reduced and the deformation of the metal plate is further increased, the metal plate on the upper side of the temperature sensor and the object on the lower side of the temperature sensor (in Example 2, the lower flat plate of the punching machine, corresponding to Figure 6 The contact area with the temperature detection object (shown by reference numeral 41 in (a)) increases, and thus the load from the metal plate is applied not only to the second portion and the sensor portion, but also to the object below, and the load on the second portion and the sensor portion becomes relatively smaller. Therefore, when the thickness t of the metal plate is further reduced, the load applied to the sensor portion changes from increasing to decreasing, and L 1MAX The value of changes from decreasing to increasing. As a result, L 1MAX The value of is a minimum value in relation to the thickness t of the metal plate. In Example 2, Figure 18 As shown in (a), L 1MAX It is understood that the minimum value is shown at t=2.0 mm.

[0097] Figure 18 (b) shows L when t = 2.0 mm and d1 = 0.06 mm. 1MAX The relationship between d1 / d2 is shown in the graph. Figure 18As shown in (b), when d1 = 0.06 mm, the 1MAX At t = 2.0 mm, the minimum value is shown. 1MAX As d1 / d2 increases (in the data of d1 / d2=0.50~0.83), it decreases linearly, but when d1 / d2 exceeds 0.83 (in the data of d1 / d2=0.92), it decreases sharply. 1MAX is 9.5 (No. 3 in Table 1). When a linear approximation is obtained from the data of d1 / d2 = 0.50 to 0.83, L 1MAX (mm) = -15 × d1 / d2 + 22 (in Figure 18 In (b), the dotted line represents the approximate straight line, and d1 / d2(-) and L 1MAX (mm) are shown together with the linear approximation formula for x and y respectively). As mentioned above, L 1MAX (mm) is the maximum L1 when no load of 10 MPa or more is applied to the sensor part. Figure 18 (b) is L 1MAX The data at t = 2.0 mm indicates the minimum value. Figure 18 The result of (b) can be understood as long as the range of d1 / d2≤0.83 and L1(mm)≤-15×d1 / d2+22 is satisfied, it can be ensured that a load exceeding 10MPa will not be applied to the sensor part. More reliably, it can be understood that within the range of d1 / d2≤0.83 and L1≤9.5mm, a load exceeding 10MPa will not be applied to the sensor part. In addition, when d1 / d2>0.83, L 1MAX Since the value of the measured value decreases rapidly, it is considered that it may be affected by the magnitude of the applied pressure (load), the measurement environment, etc.

[0098] Figure 18 (c) represents L when t = 2.0 mm and d1 / d2 = 0.5 or 0.83 1MAX A graph showing the relationship between d and d1. Figure 18 In (c), in L 1MAX At t = 2.0 mm, which represents the minimum value, if d1 / d2 is constant (0.5 or 0.83 in the example shown), then L 1MAX It is not affected by d1 and is roughly constant (roughly stable). Figure 18 The matters understood in (a) and (b) can be considered to be applicable not only to the case where d1=0.06 mm but also to the case where d1 has other values.

[0099] The results in Table 1 were obtained by deforming the metal plate positioned opposite the temperature sensor. However, similar results were also observed when the same metal plates were positioned above and below the temperature sensor and sandwiched between them. Therefore, it can be understood that, for example, when a temperature sensor with a sensor portion provided in the first portion (L1 ≤ 9.5 mm) is used between metal plates, such as between adjacent battery cells in a battery module, a d1 / d2 ratio of 0.83 or less is preferable.

[0100] In Example 2, assuming that the temperature sensor is sandwiched between adjacent battery cells in a battery module, a 60 mm square SUS plate, which is considered to be the smallest in this application, is used. A pressure of 0.5 tons, which is considered to be the largest in this application, is applied (preferably assuming an actual load rather than a pressure per unit area). Typically, the width of the sensor portion is set to 3.0 mm (see Figure 17 ), and the load applied to the sensor part is less than 10 MPa, the above results were obtained. However, when the metal plate (SUS plate) is less than 60 mm square, the applied pressure is greater than 0.5 tons, the width of the sensor part is less than 3 mm, and / or the upper limit of the load applied to the sensor part is less than 10 MPa, L with d1 / d2=0.83 1MAX The value of (in other words, the preferred upper limit value of L1 when d1 / d2≤0.83) may become smaller than 9.5 mm, and can be obtained by the same test as in Example 2.

[0101] (Example 3)

[0102] Example 3 involves reference Figure 7 The temperature sensor of the third embodiment is more specifically related to Figure 8 The specific example shown is a temperature sensor.

[0103] A flexible printed circuit board (FPC) was prepared in which a copper foil with a thickness of 10 μm was formed in a predetermined pattern on a polyimide substrate with a thickness of 10 μm. The pattern of the copper foil was as follows: Figure 19As shown schematically in (a), the outer dimensions of the comb-tooth portion of the comb-shaped electrode 3 observed from above are 1.5 mm in width and 3.0 mm in length, and the handle portion of the comb-shaped electrode 3 and the lead-out electrode portion 5 are formed on both outer sides in the width direction of the comb-tooth portion with a width of 0.5 mm and a length of 4.5 mm respectively (the area of ​​the sensor portion is 3.0 mm in width and 3.0 mm in length). On this FPC, a thermistor layer is formed with a thickness of 10 μm from the upper surface of the comb-shaped electrode 3 using the same method as the method for forming the composite layer containing metal oxide in Comparative Example 1, so as to bury the coated comb-shaped electrode 3. The outer dimensions of the thermistor layer observed from the upper surface are approximately 3.0 mm in width and 3.0 mm in length. A polyimide tape (polyimide film with an adhesive layer: thickness of approximately 30 μm) is pasted on the entire upper surface of the thermistor layer as a covering layer. Thus, as Figure 19 As shown schematically in (a) to (b), the sensor portion is covered (in Figure 19 (b), represented by the shaded area), and the thermistor element is covered with the lead-out electrode portion 5 exposed.

[0104] Meanwhile, a flexible flat cable (FFC) with a total thickness of 135 μm was prepared. Two 10 μm-thick copper traces were formed on a 100 μm-thick polyimide substrate at a 2 mm pitch, and a polyimide film coverlay was formed to cover the copper traces. The coverlay was not provided at one end of the FFC, extending 3 mm from that end, leaving the two traces exposed.

[0105] Then, an anisotropic conductive film (ACF) with a width of 3 mm and a length of 1 mm ( Figure 19 The area of ​​length L2 shown in (b) is arranged and overlapped between the wiring exposed area of ​​the FFC and the area of ​​the thermistor element not covered by the covering layer, and is bonded at 180°C while applying a load of 2 MPa. In this way, the two lead-out electrode portions 5 of the thermistor element are electrically connected to the two wirings of the FFC, respectively, to produce a temperature sensor. In the temperature sensor, the thickness of the portion between the lead-out electrode portion 5 and the wiring in the joint originating from the ACF is 10 μm. In addition, in this temperature sensor, the thickness from the back surface of the polyimide substrate of the thermistor element to the outer surface of the covering layer of the thermistor element (the total thickness d1 of the first portion and the sensor portion) is 60 μm, while the thickness from the back surface of the polyimide substrate of the thermistor element to the outer surface of the polyimide substrate of the FFC including the joint (the maximum thickness d2 of the second portion) is 140 μm. In this temperature sensor, the length L1 of the first portion is 3.5 mm, the length L2 of the second portion is 1.0 mm, and the area of ​​the joint portion (the area of ​​the first surface A' of the second portion in contact with the temperature detection object) is 3 mm. 2 .

[0106] The temperature sensor was subjected to the same load test as in Comparative Example 1. Figure 15 The results of Example 1 shown in (b) are the same as those of Example 1, and the resistance change rate in the load test can be 1% or less, and the temperature detection error can be within 1°C.

[0107] Furthermore, the back surface of the polyimide substrate of the thermistor element in the temperature sensor was attached to the surface of a 10 mm square heater set at 50°C (the actual temperature of the heater was T h ), the surface of the polyimide substrate of the FFC in the temperature sensor is brought into contact with an aluminum plate of 10 mm square and 10 mm thick, and the measured value of the temperature sensor is obtained as the temperature of the heater surface (measured temperature T m1 ). After 1 hour, T m1 -T h The temperature difference is within 0.5°C. The measured area of ​​the heater (heating area in this example) is 100mm 2 On the other hand, the area of ​​the first surface A' of the second portion of the temperature sensor in contact with the temperature detection object is 3 mm 2 Therefore, it is shown that high temperature detection accuracy can be obtained by setting the area of ​​the first surface A2 ′ to 3% or less relative to the measurement target area of ​​the temperature detection object.

[0108] In addition, the back of the polyimide substrate of the thermistor element in the temperature sensor was pasted on the surface of a 60 mm square heater set at 50°C. The surface of the polyimide substrate of the FFC in the temperature sensor was brought into contact with a 60 mm square aluminum plate with a thickness of 1 mm. A 1 mm thick fluororubber was placed on the outside of the aluminum plate. These were clamped in a punching machine and a pressure of 0.5 tons was applied (as shown in FIG. Figure 6 As shown in (b), the aluminum plate is deformed and brought into contact with the heater surface), and the measured value of the temperature sensor is obtained as the temperature of the heater surface (measured temperature T m1 ), and use another temperature measuring device to measure the surface temperature of the aluminum plate (measurement temperature T m2 ). In addition, as a case where no temperature sensor is used, a 60 mm square aluminum plate with a thickness of 1 mm is brought into contact with the surface of a 60 mm square heater set at 50°C, and a 1 mm thick fluororubber is placed on the outside of the aluminum plate. These are clamped in a punching machine and a pressure of 0.5 tons is applied. The surface temperature of the aluminum plate is measured using another temperature measuring device (measured temperature T m0 )(Also, please note that when considering thermal resistance losses, it is usually assumed that T m0 ≥T m2 ≥T m1 ). As a result, Tm0 -T m2 、T m0 -T m1 、T m2 -T m1 The temperature differences are all within 0.5° C. Therefore, it is shown that high temperature detection accuracy can be obtained even when heat dissipation is required.

[0109] In the above-mentioned method for manufacturing a thermistor element, four temperature sensors were further manufactured in the same manner except that the polyimide tape was not attached as a cover layer to the entire upper surface of the thermistor layer and the following modifications (a) to (d) were made.

[0110] (a) The back surface of the polyimide substrate (thickness 10 μm) of the thermistor element is left as is (therefore, d1 = 30 μm and d2 = 140 μm)

[0111] (b) A 30 μm thick polyimide tape (a polyimide film having an adhesive layer) is attached to the entire back surface of the polyimide substrate (thickness 10 μm) of the thermistor element (thus, d1 = 60 μm and d2 = 170 μm).

[0112] (c) A 60 μm thick polyimide tape (a polyimide film having an adhesive layer) is attached to the entire back surface of the polyimide substrate (10 μm thick) of the thermistor element (thickness d1 = 90 μm and d2 = 200 μm).

[0113] (d) A 90 μm thick polyimide tape (a polyimide film having an adhesive layer) is attached to the entire back surface of the polyimide substrate (10 μm thick) of the thermistor element (thickness d1 = 120 μm and d2 = 230 μm).

[0114] Each of the four temperature sensors was evaluated in the same manner as above. Specifically, in the temperature sensor, the back surface of the polyimide substrate of the thermistor element was attached to the surface of a 60 mm square heater set at 50°C. The surface of the polyimide substrate of the FFC in the temperature sensor was brought into contact with a 60 mm square aluminum plate with a thickness of 1 mm. A 1 mm thick fluororubber was then placed on the outside of the aluminum plate. These were then clamped in a press and a pressure of 0.5 tons was applied (e.g., Figure 6 As shown in (b), the aluminum plate is deformed and brought into contact with the heater surface), and the measured value of the temperature sensor is obtained as the temperature of the heater surface (measured temperature T m1 ), and use another temperature measuring device to measure the surface temperature of the aluminum plate (measurement temperature T m2 ). As a result, in any of the four temperature sensors, T m0 -T m2 、Tm0 -T m1 、T m2 -T m1 The temperature difference is within 0.5°C. Therefore, it can be seen that when the maximum thickness d2 is 230 μm or less, and particularly 200 μm or less, the thickness of the polyimide substrate between the sensor portion and the temperature detection object (the thickness of the first portion (and the first portion expansion portion)) does not substantially affect the temperature detection accuracy.

[0115] The effects shown in Example 3 are also considered to be obtainable when the arrangement of the thermistor layer and the electrodes is changed in the structure of the sensor portion as in Example 1, or when split electrodes or planar electrodes are used instead of the comb-shaped electrodes.

[0116] (Example 4)

[0117] Example 4 involves reference Figure 12 The temperature sensor array of the fourth embodiment.

[0118] Three thermistor elements were fabricated in the same manner as in Example 3. Separately, a flexible flat cable (FFC) with a total thickness of 135 μm was prepared. Six copper traces, each 10 μm thick, were formed on a polyimide substrate at alternating intervals of 2 mm and 1 mm. A polyimide film cover was formed to cover the copper traces. The cover was not provided at either end of the FFC, extending 3 mm from the ends, leaving the six traces exposed. At the other end of the FFC, a reinforcing plate was placed on the surface of the polyimide substrate opposite the exposed trace area.

[0119] Then, an anisotropic conductive film (ACF) with a width of 9 mm and a length of 1 mm is arranged and overlapped between the wiring exposed area of ​​the FFC (one end without a reinforcing plate) and the area of ​​the three thermistor elements not covered by the covering layer, and is joined at 180°C while applying a load of 2 MPa. Thus, the two lead-out electrode portions 5 of each of the three thermistor elements are electrically connected to the six wirings of the FFC. The structure thus obtained is divided into three parts, leaving the other end side where the reinforcing plate is present, so that each of the six wirings of the FFC becomes two. Then, the other end side part where the reinforcing plate is present is inserted into a 9-pin connector with a 1 mm pitch sold on the market and connected to it. Thus, a Figure 12 Schematic representation of the temperature sensor array.

[0120] The manufactured temperature sensor array was able to connect the connector to the measurement circuit board, and similarly to Example 3, high temperature detection accuracy was achieved in all three sensor units.

[0121] Furthermore, the description given in the third embodiment can also be applied to the temperature sensor array of the fourth embodiment.

[0122] Industrial applicability

[0123] The temperature sensor and temperature sensor array of the present invention can be configured to be flexible and thin as a whole and can be used for various applications for detecting the temperature of a temperature detection object. For example, they can be suitably used to detect the temperature of a temperature detection object while in contact with and pressed against the temperature detection object (particularly, when pressed between the temperature detection object and an opposing object).

[0124] This application claims priority based on Japanese Patent Application No. 2020-64343 filed in Japan on March 31, 2020, the entire contents of which are incorporated herein by reference.

[0125] Description of Reference Numerals

[0126] 1...thermistor layer; 3, 3'...electrode; 5...lead-out electrode portion; 7...covering layer; 10...sensor portion; 11...first portion; 12, 12'...second portion; 12a...first portion expansion portion; 12b...third portion expansion portion; 12c...joining portion; 13...third portion; 15, 15'...thermal insulating material or heat dissipating material; 20, 20', 20"...flexible substrate; 21...first substrate; 23...second substrate; 25...wiring; 27...covering layer; 29...reinforcement plate; 30, 30', 30", 30A, 30B, 30C...temperature sensors; 31...common connection portion; 40...temperature sensor array; 41...temperature detection object; 43...opposing object; 50...lithium-ion battery module; 51...battery cell; 53...battery module circuit substrate; 55...circuit substrate for temperature sensor array; A1...surface opposite to the sensor portion; B1...exposed surface of the sensor portion; A2, A2"...first surface; B2, B2'...second surface; A3...third surface; B3...fourth surface; d1, d2, d3...thickness; X, Y...ends.

Claims

1. A temperature sensor having a sensor portion formed on a flexible substrate, wherein: The flexible substrate comprises: a first portion located at an end portion of the flexible substrate and forming the sensor portion; and The second portion is adjacent to the first portion in a direction from the end toward the distal portion and has a maximum thickness between the first surface and the second surface facing each other. The surface of the first portion opposite to the sensor portion and the first surface of the second portion are located on the same plane. At least the first surface of the second portion forms a detection surface in contact with the object to be detected. The total thickness of the first portion and the sensor portion is smaller than the maximum thickness of the second portion.

2. The temperature sensor according to claim 1, wherein A ratio of a total thickness of the first portion and the sensor portion to the maximum thickness of the second portion is 0.83 or less, and a length of the first portion is 9.5 mm or less.

3. The temperature sensor according to claim 1 or 2, wherein: The flexible substrate further includes a third portion that is adjacent to the second portion in a direction from the end toward a distal position and has a thickness smaller than the maximum thickness between a third surface and a fourth surface that are opposed to each other. The fourth surface of the third portion and the second surface of the second portion are located on the same plane.

4. The temperature sensor according to claim 3, wherein: The third surface of the third portion is exposed. The temperature sensor according to claim 3 , wherein: The third surface of the third portion is covered with a heat insulating material or a heat dissipating material that contacts the temperature detection object. The temperature sensor according to claim 3 , wherein: The second portion includes an expanded portion from the first portion, an expanded portion from the third portion, and a joining portion joining the expanded portions.

7. The temperature sensor according to claim 6, wherein: The first portion and the extension portion from the first portion include a first substrate and two electrode portions formed on the first substrate and extending from the sensor portion. The third portion and the extension portion from the third portion include a second substrate and two wirings formed on the second substrate. The two electrode portions and the two wirings are electrically connected via the bonding portion.

8. The temperature sensor according to claim 1 or 2, wherein: The sensor portion includes a thermistor layer, two electrodes that are in contact with the thermistor layer and are arranged to be separated from each other, and a cover layer, if present.

9. A temperature sensor array, wherein: The temperature sensor array includes a plurality of temperature sensors according to any one of claims 1 to 8, wherein the plurality of temperature sensors are connected to a common connection portion at or near an end portion of the flexible substrate opposite to the first portion.

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