Strain gauge module

Abstract

To provide a strain gauge module that is excellent in detection sensitivity.SOLUTION: A strain gauge module is mounted to an object to be measured, and is configured to include a film-like strain detection device having a terminal and a resistor region on an upper surface to detect a strain generated in the object to be measured, and a thin metal substrate having the upper surface and a lower surface. The film-like strain detection device is mounted on the upper surface of the thin metal substrate through an adhesive, the lower surface is a mounting surface to the object to be measured, and a center of gravity of the thin metal substrate and a center of gravity of the resistor region coincide with each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a strain gauge module. [Background technology]

[0002] As a film-like device, for example, a strain gauge having a resistor formed on a substrate such as a flexible polyimide is known (see, for example, Patent Document 1). In such a film-like device, there is a demand for improving the detection sensitivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-185346 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in view of the above-mentioned points, and has an object to provide a strain gauge module with excellent detection sensitivity. [Means for solving the problem]

[0005] This strain gauge module (1) is composed of a film-shaped strain detection device (30) that is attached to an object to be measured and has terminals (34, 35) and a resistor region (R) on its upper surface for detecting strain occurring in the object to be measured, and a thin metal substrate (10) having an upper surface (10a) and a lower surface (10b), wherein the film-shaped strain detection device (30) is mounted on the upper surface (10a) of the thin metal substrate (10) via an adhesive (20), the lower surface (10b) serves as an attachment surface for the object to be measured, and the center of gravity (Gp) of the thin metal substrate (10) and the center of gravity (Gr) of the resistor region (R) coincide with each other.

[0006] The reference symbols in parentheses are given for ease of understanding, are merely examples, and are not intended to be limiting of the embodiments shown in the drawings. Effect of the Invention

[0007] According to the disclosed technique, a strain gauge module with excellent detection sensitivity can be provided. [Brief description of the drawings]

[0008] [Figure 1] 1 is a plan view illustrating a strain gauge module according to an embodiment of the present invention; [Diagram 2] 1 is a cross-sectional view illustrating a strain gauge module according to an embodiment of the present invention. [Diagram 3] FIG. 1 is a diagram illustrating the relationship between surface roughness Ra and the thickness of an adhesive. [Figure 4] FIG. 4 is a diagram illustrating a resistor region. [Diagram 5] 10A and 10B are diagrams illustrating the coincidence of the center of gravity of the thin metal substrate and the resistor region. [Figure 6] 13 is a plan view illustrating a strain gauge module according to a modified example of the embodiment. FIG. [Figure 7] FIG. 13 is a diagram illustrating a rate of change in sensitivity to detection of distortion. [Figure 8] 1 is a diagram illustrating a processing system for a signal output from a strain gauge module according to an embodiment of the present invention. [Figure 9] FIG. 13 is a diagram illustrating an example of an output voltage of a strain gauge module according to a comparative example. [Figure 10] 4 is a diagram illustrating an example of an output voltage of the strain gauge module according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0010] (Strain gauge module) Fig. 1 is a plan view illustrating a strain gauge module according to the present embodiment. Fig. 2 is a cross-sectional view illustrating the strain gauge module according to the present embodiment, showing a cross section along line AA in Fig. 1. Fig. 3 is a diagram for explaining the surface roughness Ra and the thickness of the adhesive.

[0011] 1 and 2, the strain gauge module 1 includes a thin metal substrate 10, an adhesive 20, and a film-like strain detection device 30. The strain gauge module 1 is attached to an object to be measured and can detect strain occurring in the object to be measured.

[0012] The thin plate metal substrate 10 is a member on which the film-shaped strain detection device 30 is disposed. In detail, the thin plate metal substrate 10 has an upper surface 10a and a lower surface 10b. The film-shaped strain detection device 30 is mounted on the upper surface 10a of the thin plate metal substrate 10, and the lower surface 10b is a surface to be attached to an object to be measured.

[0013] Here, the thin metal substrate refers to a metal substrate having a thickness of 200 μm or less. The thickness of the thin metal substrate 10 is preferably 20 μm or more and 120 μm or less, more preferably 20 μm or more and 80 μm or less, and even more preferably 20 μm or more and 50 μm or less.

[0014] By making the thickness of the thin metal substrate 10 20 μm or more, the strain can be stably detected. By making the thickness of the thin metal substrate 10 120 μm or less, the strain can be detected with good sensitivity. Furthermore, by making the thickness of the thin metal substrate 10 thinner, the strain can be detected with even better sensitivity. Furthermore, if the thickness of the thin metal substrate 10 is 20 μm or more and 80 μm or less, the thin metal substrate 10 can be easily fixed to a curved measurement object. If the thickness of the thin metal substrate 10 is 20 μm or more and 50 μm or less, the thin metal substrate 10 can be even more easily fixed to a curved measurement object.

[0015] The surface roughness Ra of the upper surface 10a of the thin plate metal substrate 10 is preferably 3 μm to 20 μm, more preferably 3 μm to 10 μm, and even more preferably 3 μm to 5 μm. By setting the surface roughness Ra of the upper surface 10a of the thin plate metal substrate 10 to 3 μm to 20 μm, it is possible to reduce the effect of the surface roughness Ra of the upper surface 10a of the thin plate metal substrate 10 on the film-shaped strain detection device 30, and the strain can be easily and accurately measured.

[0016] Here, the surface roughness Ra is a type of numerical value that indicates surface roughness, and is called the arithmetic mean roughness. Specifically, as shown in FIG. 3, it is the arithmetic mean of the absolute value of the height change within a reference length l measured from the surface, which is the average line.

[0017] The material of the thin metal substrate 10 is preferably SUS (stainless steel) which has high hardness (easy propagation of strain) for transmitting strain, but is not limited thereto, and aluminum, copper alloy, etc. may also be used. SUS is also preferable because it is easily available. The size of the thin metal substrate 10 is not particularly limited, but is larger than the size of the film-shaped strain detection device 30 in a planar view.

[0018] The film-shaped strain detection device 30 is mounted on the upper surface 10a of the thin metal substrate 10 via an adhesive 20. For example, an epoxy resin or the like can be used as the adhesive 20. The flexural modulus of the adhesive 20 can be, for example, 3 GPa or more and 20 GPa or less. The adhesive 20 may contain a filler as necessary. When the adhesive 20 contains a filler, the filler contained may be an inorganic filler or an organic filler. When the adhesive 20 contains an inorganic filler, the filler diameter is preferably 5 μm or less, and when the adhesive 20 contains an organic filler, the filler diameter is preferably 10 μm or less.

[0019] The thickness T of the adhesive 20 is preferably 30 μm or less. If the thickness T of the adhesive 20 is 30 μm or less, the distortion of the thin plate metal substrate 10 can be efficiently transmitted to the film-like distortion detection device 30. As shown in FIG. 3, the thickness T of the adhesive 20 is the distance from the tip of the convex portion shown by the solid line, excluding the abnormal protrusion (spike), on the upper surface 10a of the thin plate metal substrate 10 to the lower surface of the base material 31. The unevenness shown by the dashed line in FIG. 3 is a virtual image. The portion U in FIG. 3, i.e., the gap between the unevenness of the upper surface 10a of the thin plate metal substrate 10, is filled with the adhesive 20.

[0020] It is preferable that the entire lower surface of the film-shaped strain detection device 30 is adhered to the upper surface 10a of the thin plate metal substrate 10 by the adhesive 20. In this case, it is preferable that the variation in thickness of the adhesive 20 is ±5 μm or less. This allows the entire film-shaped strain detection device 30 to be held flat on the upper surface 10a of the thin plate metal substrate 10, so that the strain of the thin plate metal substrate 10 can be transmitted to the film-shaped strain detection device 30 more efficiently.

[0021] The film-shaped strain detection device 30 has a substrate 31, a resistor 32, wiring 33, and terminals 34 and 35. There are no particular limitations on the size of the film-shaped strain detection device 30, but from the viewpoint of miniaturizing the strain gauge module 1, it is preferable that the film-shaped strain detection device 30 is also small, and for example, the substrate 31 can be in a square or rectangular shape with one side measuring approximately 1.5 mm to 2 mm.

[0022] The substrate 31 is a flexible member that serves as a base layer for forming the resistor 32. There is no particular limit to the thickness of the substrate 31, and it can be appropriately selected depending on the purpose. The substrate 31 can be formed from an insulating resin film such as a PI (polyimide) resin.

[0023] The resistor 32 is a thin film formed on the upper surface of the substrate 31, and is a sensing part that generates a resistance change when strained. The resistor 32 may be formed directly on the upper surface of the substrate 31, or may be formed on the upper surface of the substrate 31 via another layer. There is no particular limit to the thickness of the resistor 32, and it can be appropriately selected depending on the purpose, but it is, for example, 0.05 μm or more and 50 μm or less.

[0024] The resistor 32 has a structure in which multiple elongated parts are arranged at regular intervals with their longitudinal direction in the same direction (the direction perpendicular to the line AA in the example of FIG. 1), and the ends of adjacent elongated parts are alternately connected, folding back in a zigzag pattern as a whole. The longitudinal direction of the multiple elongated parts is the grid direction, and the direction perpendicular to the grid direction is the grid width direction (the direction of the line AA in the example of FIG. 1).

[0025] The resistor 32 can be made of, for example, a material containing Cr (chromium), a material containing Ni (nickel), or a material containing both Cr and Ni. That is, the resistor 32 can be made of a material containing at least one of Cr and Ni. An example of a material containing Ni is Cu-Ni (copper-nickel). An example of a material containing both Cr and Ni is Ni-Cr (nickel-chromium).

[0026] The resistor 32 may be made of a Cr mixed-phase film. Here, the Cr mixed-phase film is made of Cr, CrN, Cr 2 The Cr mixed-phase film may contain unavoidable impurities such as chromium oxide. When the Cr mixed-phase film is used as the resistor 32, the film-shaped strain detection device 30 can be made highly sensitive and compact.

[0027] The terminals 34 and 35 are formed on the upper surface near the end of the wiring 33. The terminals 34 and 35 are connected to both ends of the resistor 32 via the wiring 33 made of copper or the like, and are formed, for example, in a rectangular shape in a plan view. The terminals 34 and 35 are a pair of electrodes for outputting a change in the resistance value of the resistor 32 caused by distortion. The terminals 34 and 35 are made of, for example, copper or the like. A gold film or the like may be laminated on the surface of the copper or the like.

[0028] 2, the strain gauge module 1 may have a resin part 36 covering the film-shaped strain detection device 30 on the thin plate metal substrate 10. The resin part 36 can be formed, for example, so as to expose a part or all of the terminals 34 and 35 of the film-shaped strain detection device 30. By providing the resin part 36 covering the film-shaped strain detection device 30 on the thin plate metal substrate 10, the mechanical strength of the terminals 34 and 35 of the film-shaped strain detection device 30 can be improved, and the environmental resistance (humidity, gas) of the film-shaped strain detection device 30 can be improved.

[0029] In order to suppress the output (offset) of the film-shaped strain detection device 30 when no strain is applied, the resin part 36 is preferably made of a material that does not contain filler or that contains inorganic or organic filler of 3 μm or less. The resin part 36 is preferably made of a material that has a hardness suitable for strain propagation of D90 to A15 and a tensile strength of 0.3 MPa to 10 MPa. Examples of such materials include thermosetting or photosetting silicone resins and epoxy resins. By using such a low-stress resin as the material for the resin part 36, the effect of covering the film-shaped strain detection device 30 with the resin part 36 on its characteristics (sensitivity) can be reduced.

[0030] Since the bottom layer of the strain gauge module 1 is the thin metal substrate 10, the bottom surface 10b of the thin metal substrate 10 can be easily fixed to the object to be measured using a liquid or film (tape) adhesive or pressure-sensitive adhesive. The thickness of the adhesive or pressure-sensitive adhesive can be, for example, about 25 μm.

[0031] That is, the strain gauge module 1 is easy to attach to the measurement object because the bottom layer is not made of flexible resin (polyimide, etc.) as in conventional strain gauges. Also, since polyimide is a poorly adhesive material, a special adhesion method (heating and pressure) is required to attach it to the measurement object, but no special adhesion method is required to attach the thin metal substrate 10 to the measurement object.

[0032] [Positional relationship between the thin metal substrate and the resistor area] The thin metal substrate 10 is preferably rectangular in plan view. By making the thin metal substrate 10 rectangular in plan view, the longitudinal strain can be detected with good sensitivity. In FIG. 1, the thin metal substrate 10 is rectangular in plan view, and a straight line L1 indicates a line passing through the midpoints of the opposing short sides of the thin metal substrate 10. That is, the straight line L1 is a line that divides the thin metal substrate 10 in half in the longitudinal direction. Also, a straight line L2 indicates a line that passes through the midpoints of the opposing long sides of the thin metal substrate 10. That is, the straight line L2 is a line that divides the thin metal substrate 10 in half in the lateral direction. The intersection of the straight lines L1 and L2 passes through the center of gravity Gp of the thin metal substrate 10 in plan view. The center of gravity here is the center of gravity in plan view, that is, the center of gravity of a plane figure. For example, the center of gravity Gp of the thin metal substrate 10 is the center of gravity of a rectangle shown in FIG. 1 without considering the thickness of the thin metal substrate 10.

[0033] The film-shaped strain detection device 30 has a resistor region R on its upper surface. As shown in Fig. 4, the resistor region R is a rectangular region in a plan view on the upper surface of the substrate 31 where the resistor 32 is formed. The resistor region R is the smallest rectangular region that can be drawn so as to include all of the resistor 32. Gr shown in Fig. 4 indicates the center of gravity of the resistor region R.

[0034] As shown in Fig. 5, in the strain gauge module 1, the center of gravity Gp of the thin metal substrate 10 and the center of gravity Gr of the resistor region R coincide with each other. In this application, "the centers of gravity of A and B coincide with each other" includes not only the case where the centers of gravity of A and B completely coincide with each other in a plan view, but also the case where the deviation between the centers of gravity of A and B is within a range of 50 µm. In addition, the direction of deviation may be arbitrary, and it is sufficient that the center of gravity of B is located within a radius of 50 µm from the center of gravity of A.

[0035] Furthermore, the fact that the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R coincide with each other means that, if the thin plate metal substrate 10 and the resistor region R are rectangular in plan view, the intersection of the diagonals of the thin plate metal substrate 10 coincides with the intersection of the diagonals of the resistor region R. The allowable amount of deviation between the intersection of the diagonals of the thin plate metal substrate 10 and the intersection of the diagonals of the resistor region R is the same as in the above case. In other words, if the amount of deviation between the intersections of the two diagonals is within a range of 50 μm, the intersections of the two diagonals are considered to coincide with each other.

[0036] The center of gravity Gp of the thin plate metal substrate 10 is the point at which strain is most concentrated when the thin plate metal substrate 10 is attached to an object to be measured and receives strain from the object to be measured. Therefore, by making the center of gravity Gp of the thin plate metal substrate 10 coincident with the center of gravity Gr of the resistor region R, the strain detection sensitivity of the film-shaped strain detection device 30 can be improved. In other words, a strain gauge module 1 with excellent detection sensitivity can be realized. This effect can also be obtained when the thin plate metal substrate 10 is not rectangular in plan view.

[0037] From the viewpoint of further improving the strain detection sensitivity in the film-shaped strain detection device 30, it is preferable that the center of gravity Gr of the resistor region R be located within a radius of 20 μm of the center of gravity Gp of the thin plate metal substrate 10, it is more preferable that the center of gravity Gr of the resistor region R be located within a radius of 10 μm, it is even more preferable that the center of gravity Gr of the resistor region R be located within a radius of 5 μm, and it is particularly preferable that the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R completely coincide with each other.

[0038] Arrow B in Fig. 1 indicates the vibration propagation direction. When the thin plate metal substrate 10 is rectangular in plan view, it is preferable that the vibration propagation direction B and the longitudinal direction of the thin plate metal substrate 10 coincide. It is also preferable that the vibration propagation direction B and the grid direction of the resistors 32 formed in the resistor region R coincide. In other words, it is preferable that the longitudinal direction of the thin plate metal substrate 10 and the grid direction of the resistors 32 formed in the resistor region R coincide. This relationship can improve the detection sensitivity of distortion in the vibration propagation direction B.

[0039] The positional relationship between the resistor region R and the terminals 34 and 35 is not limited to the example in Fig. 1. For example, as in the strain gauge module 1A shown in Fig. 6, the positions of the terminals 34 and 35 may be different in the longitudinal direction of the thin plate metal substrate 10. Of course, the terminals 34 and 35 may be located at positions other than those shown in Figs. 1 and 6. What is important is that the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R should coincide with each other, and this coincidence improves the strain detection sensitivity of the film-shaped strain detection device 30.

[0040] [Changes in detection sensitivity] In the strain gauge module 1, the rate of change in the detection sensitivity of the film-shaped strain detection device 30 when the stress changes was investigated for the cases where the deviation between the center of gravity Gp of the thin metal substrate 10 and the center of gravity Gr of the resistor region R was 5 μm in the longitudinal direction of the thin metal substrate 10, and where the deviation between the center of gravity Gp of the thin metal substrate 10 and the center of gravity Gr of the resistor region R was 50 μm in the longitudinal direction of the thin metal substrate 10.

[0041] Fig. 7 is a diagram showing the rate of change in detection sensitivity of strain. As shown in Fig. 7, when the amount of deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R is 5 µm in the longitudinal direction of the thin plate metal substrate 10, the rate of change in detection sensitivity when the stress is 100 is about -2%. In contrast, when the amount of deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R is 50 µm in the longitudinal direction of the thin plate metal substrate 10, the rate of change in detection sensitivity when the stress is 100 is about -5%.

[0042] If the rate of change in detection sensitivity when the stress is 100 is about -5%, practical use is possible. Therefore, based on the data in Figure 7, it can be said that the allowable deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R for the strain gauge module 1 is 50 μm in the longitudinal direction of the thin plate metal substrate 10.

[0043] Furthermore, the detection sensitivity improves as the deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R decreases, and it can be said that sufficient sensitivity is obtained when the deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R is 5 μm in the longitudinal direction of the thin plate metal substrate 10.

[0044] The rate of change in the strain detection sensitivity is greatest when the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R are misaligned in the longitudinal direction of the thin plate metal substrate 10. Therefore, it can be said that the allowable misalignment between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R for the strain gauge module 1 is within a range of 50 μm in all directions.

[0045] [An example of signal processing] Here, an example of a signal processing process using a strain gauge module will be described. Fig. 8 is a diagram illustrating a processing system for a signal output from a strain gauge module according to this embodiment. In Fig. 8, a strain gauge module 1 is used, but a strain gauge module 1A may also be used.

[0046] 8, the output of the strain gauge module 1 is connected to a bridge box 100. For example, terminals 34 and 35 of the film-shaped strain detection device 30 mounted on the strain gauge module 1 are connected to the bridge box 100 by wires or the like. The bridge box 100 is connected to a signal processing unit 200. The signal processing unit 200 has, for example, a bridge voltage 210, a strain amplifier 220, and an A / D converter 230.

[0047] For example, a bridge circuit is disposed within the bridge box 100, one side of which is configured with a resistor 32 connected between terminals 34 and 35, and the other three sides are configured with fixed resistors. A DC voltage is supplied from a bridge voltage 210 to the bridge circuit within the bridge box 100. As a result, an analog signal corresponding to the resistance value of the resistor 32 can be obtained as the output of the bridge circuit.

[0048] The analog signal obtained by the bridge box 100 is input to the distortion amplifier 220 and amplified by the distortion amplifier 220. The analog signal amplified by the distortion amplifier 220 is converted to a digital signal by the A / D converter 230 and input to the computer 300 where a predetermined calculation or the like is performed. For example, a storage device 400 is connected to the computer 300, and the results of the calculations by the computer 300 and the like are stored.

[0049] Fig. 9 is a diagram illustrating an output voltage of a strain gauge module according to a comparative example. Fig. 9(a) shows the output voltage output from the bridge box 100 when the strain gauge module according to the comparative example is connected instead of the strain gauge module 1 in Fig. 8, and Fig. 9(b) shows the output voltage output from the strain amplifier 220. The strain gauge module according to the comparative example has the same structure as the strain gauge module 1, except that the deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R is 100 μm in the longitudinal direction of the thin plate metal substrate 10.

[0050] Fig. 10 is a diagram illustrating an example of an output voltage of the strain gauge module according to the present embodiment. Fig. 10(a) is the output voltage output from the bridge box 100 in Fig. 8, and Fig. 10(b) is the output voltage output from the strain amplifier 220 in Fig. 8. Here, a strain gauge module 1 was used in which the deviation between the center of gravity Gp of the thin plate metal substrate 10 and the center of gravity Gr of the resistor region R was 5 μm in the longitudinal direction of the thin plate metal substrate 10.

[0051] The strain gauge module 1 has a higher detection sensitivity than the strain gauge module according to the comparative example because the amount of deviation between the center of gravity Gp of the thin metal substrate 10 and the center of gravity Gr of the resistor region R is smaller. Therefore, as can be seen by comparing Fig. 9(a) with Fig. 10(a), the strain gauge module 1 can obtain an output voltage with a larger amplitude from the bridge box 100 than the strain gauge module according to the comparative example.

[0052] Furthermore, when using the strain gauge module 1, which has high detection sensitivity and can obtain an output voltage with a large amplitude from the bridge box 100, the gain of the strain amplifier 220 can be made lower than when using the strain gauge module according to the comparative example. Therefore, as can be seen by comparing Fig. 9(b) with Fig. 10(b), when the strain gauge module 1 is used, the influence of noise from the strain amplifier 220 can be reduced and an output voltage with a high S / N ratio can be obtained compared to when using the strain gauge module according to the comparative example. As a result, the use of the strain gauge module 1 enables highly accurate strain detection.

[0053] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0054] 1,1A strain gauge module, 10 thin metal substrate, 10a upper surface, 10b lower surface, 20 adhesive, 30 film-shaped strain detection device, 31 substrate, 32 resistor, 33 wiring, 34, 35 terminal, 36 resin part, 100 bridge box, 200 signal processing part, 210 bridge voltage, 220 strain amplifier, 230 A / D converter, 300 computer, 400 storage device

Claims

1. The film-shaped strain detection device is attached to a measurement object and has a terminal and a resistor region on an upper surface thereof for detecting a strain occurring in the measurement object, and is configured to include a thin metal substrate having an upper surface and a lower surface, the film-shaped strain detection device is mounted on the upper surface of the thin metal substrate via an adhesive, and the lower surface is used as an attachment surface for the measurement object; A strain gauge module, wherein the center of gravity of the thin metal substrate coincides with the center of gravity of the resistor region.

2. 2. The strain gauge module according to claim 1, wherein the thin metal substrate and the resistor region are rectangular in plan view, and an intersection of diagonals of the thin metal substrate and an intersection of diagonals of the resistor region coincide with each other.

3. The thin metal substrate is rectangular in plan view, 3. The strain gauge module according to claim 1, wherein a longitudinal direction of the thin metal substrate coincides with a grid direction of the resistors formed in the resistor region.

4. 4. The strain gauge module according to claim 1, wherein the adhesive has a thickness of 30 [mu]m or less.

5. the entire lower surface of the film-shaped strain detection device is adhered to the upper surface of the thin metal substrate by the adhesive; 5. The strain gauge module according to claim 4, wherein the thickness of the adhesive varies within ±5 [mu]m.

6. 6. The strain gauge module according to claim 1, wherein the thin metal substrate has a thickness of 20 μm or more and 120 μm or less.

7. 7. The strain gauge module according to claim 1, wherein the surface roughness Ra of the upper surface of the thin metal substrate is 3 [mu]m or more and 20 [mu]m or less.

8. 8. The strain gauge module according to claim 1, wherein the material of the thin metal substrate is stainless steel.

9. 9. The strain gauge module according to claim 1, wherein the film-shaped strain detection device includes a substrate made of polyimide and a resistor formed on the substrate.

10. The film-shaped strain detection device is attached to a measurement object and has a terminal and a resistor region on an upper surface thereof for detecting a strain occurring in the measurement object, and is configured to include a thin metal substrate having an upper surface and a lower surface, the film-shaped strain detection device is mounted on the upper surface of the thin metal substrate via an adhesive, and the lower surface is used as an attachment surface for the measurement object; A strain gauge module, wherein the center of gravity of the resistor region is located within a radius of 50 μm from the center of gravity of the thin metal substrate.

11. 11. The strain gauge module according to claim 10, wherein the amount of deviation of the center of gravity of the resistor region from the center of gravity of the thin metal substrate in the longitudinal direction of the thin metal substrate is within 50 [mu]m.

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