阅读说明：本技术 应变片及传感器模块 (Strain gauge and sensor module ) 是由 相泽祐汰 北村厚 美齐津英司 汤口昭代 于 2018-12-25 设计创作，主要内容包括：本应变片包括：基材,具有可挠性；以及多个电阻体,在所述基材上,由Cr混合相膜形成,其中,所述多个电阻体包括以当将所述基材粘贴在挠曲体上时夹着所述挠曲体且位于相对的位置的方式布置的两个电阻体。(This foil gage includes: a substrate having flexibility; and a plurality of resistor bodies formed of a Cr mixed phase film on the base material, wherein the plurality of resistor bodies include two resistor bodies arranged so as to be located at opposite positions with the flexure body therebetween when the base material is stuck on the flexure body.)

1. A strain gage, comprising:

a substrate having flexibility; and

a plurality of resistors formed on the substrate from a Cr mixed phase film,

wherein the plurality of resistors include two resistors arranged so as to be positioned in opposing positions with the flexure interposed therebetween when the base material is bonded to the flexure.

2. The strain gage of claim 1, wherein,

the substrate has a first region capable of being affixed to a first surface of the flexure and second and third regions capable of being affixed to second and third surfaces adjacent to the first surface and opposite each other,

one of the two resistive bodies is disposed in the second region, and the other of the two resistive bodies is disposed in the third region.

3. The strain gage of claim 2, further comprising:

a first electrode electrically connected to one of the two resistor bodies, and a second electrode electrically connected to the other of the two resistor bodies,

wherein the first electrode and the second electrode are disposed in the first region.

4. The strain gage of any of claims 1-3,

the two resistors are arranged on the substrate such that the grid directions are oriented in the same direction.

5. The strain gage of any of claims 1-4,

the plurality of resistors have α -chromium as a main component.

6. The strain gage of claim 5, wherein,

the plurality of resistors contain 80% by weight or more of alpha-chromium.

7. The strain gage of claim 5 or 6,

the plurality of resistors include chromium nitride.

8. The strain gage of any of claims 1-7, further comprising:

and a functional layer formed of a metal, an alloy, or a metal compound in a lower layer of the plurality of resistors.

9. The strain gage of claim 8, wherein,

the functional layer has a function of promoting crystal growth of the plurality of resistor elements.

10. The strain gage of any of claims 1-9, further comprising:

and an insulating resin layer covering at least one of the plurality of resistors.

11. A sensor module, comprising:

a strain gage according to any one of claims 1 to 10; and

the flexible body is adhered with the base material,

wherein the two resistor bodies are arranged at opposite positions so as to sandwich the flexure body.

Technical Field

The invention relates to a strain gauge (strain gauge) and a sensor module.

Background

A strain gauge is known which is attached to an object to be measured to detect strain of the object to be measured. The strain gauge has a resistor for detecting strain, and a material containing Cr (chromium) or Ni (nickel), for example, is used as a material of the resistor. In addition, for example, one resistor is formed on one surface of a base material made of an insulating resin (see, for example, patent document 1).

< Prior Art document >

< patent document >

Patent document 1: japanese unexamined patent application publication No. 2016-74934

Disclosure of Invention

< problems to be solved by the present invention >

However, a plurality of strain gauges each having one resistor are prepared and are bonded to different surfaces of the flexure to measure strain. In this case, since it takes time to attach the respective strain gauges to different surfaces of the flexure, improvement in work efficiency is sought.

In view of the above problems, an object of the present invention is to provide a strain gauge that can achieve an efficient attachment work to a flexure.

< means for solving the problems >

This foil gage includes: a substrate having flexibility; and a plurality of resistor bodies formed of a Cr mixed phase film on the base material, wherein the plurality of resistor bodies include two resistor bodies arranged so as to be located at opposite positions with the flexure body therebetween when the base material is stuck on the flexure body.

< effects of the invention >

According to the disclosed technology, a strain gauge can be provided that can achieve an efficient attachment work for a flexure.

Drawings

Fig. 1 is a plan view showing a strain gauge according to embodiment 1.

Fig. 2 is a sectional view (1 thereof) showing a strain gauge according to embodiment 1.

Fig. 3 is a perspective view showing a sensor module according to embodiment 1.

Fig. 4 is a sectional view showing a sensor module according to embodiment 1.

Fig. 5 is a sectional view showing a strain gauge according to embodiment 1 (2 thereof).

Fig. 6 is a plan view showing a strain gauge according to modification 1 of embodiment 1.

Fig. 7 is a perspective view showing a sensor module according to modification 1 of embodiment 1.

Detailed Description

Hereinafter, embodiments 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 overlapping description may be omitted.

< embodiment 1>

Fig. 1 is a plan view showing a strain gauge according to embodiment 1. Fig. 2 is a sectional view showing a strain gauge according to embodiment 1, showing a section along line a-a of fig. 1. As shown in fig. 1 and 2, the strain gauge 1 has a substrate 10, resistors 31 and 32, wiring patterns 41 and 42, and terminal portions 51 and 52.

In the present embodiment, for convenience, the strain gauge 1 has the side of the substrate 10 on which the resistors 31 and 32 are provided as the upper side or one side, and the side on which the resistors 31 and 32 are not provided as the lower side or the other side. The surface of each portion on which the resistors 31 and 32 are provided is referred to as one surface or upper surface, and the surface on which the resistors 31 and 32 are not provided is referred to as the other surface or lower surface. However, the strain gauge 1 may be used in an upside-down state, or the strain gauge 1 may be arranged at an arbitrary angle. The plan view is a view of the object viewed from the direction normal to the upper surface 10a of the substrate 10, and the planar shape is a shape of the object viewed from the direction normal to the upper surface 10a of the substrate 10.

The base material 10 is a member for forming a base layer of the resistors 31 and 32 and the like, and has flexibility. In the present embodiment, the planar shape of the substrate 10 is a belt shape. The thickness of the substrate 10 is not particularly limited and may be appropriately selected according to the purpose, and may be, for example, about 5 μm to 1000 μm. In particular, the thickness of the substrate 10 is preferably 5 μm to 200 μm from the viewpoint of transferability of strain from the surface of a flexible element (flexible element) bonded to the lower surface of the substrate 10 via an adhesive layer or the like and dimensional stability against the environment, and more preferably 10 μm or more from the viewpoint of insulation.

The substrate 10 may be formed of an insulating resin film such as PI (polyimide) resin, epoxy resin, PEEK (polyether ether ketone) resin, PEN (polyethylene naphthalate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, or polyolefin resin. The thin film is a member having a thickness of about 500 μm or less and having flexibility.

Here, "formed of an insulating resin film" does not prevent the insulating resin film of the substrate 10 from containing a filler, impurities, or the like. The substrate 10 may be formed of an insulating resin film containing a filler such as silica or alumina.

The resistors 31 and 32 are sensing portions formed on the substrate 10 and subjected to strain to cause a change in resistance. The resistors 31 and 32 may be arranged on the substrate 10 such that the grid directions are oriented in the same direction, for example. In fig. 1, for convenience, the resistors 31 and 32 are shown in a hatched pattern.

The resistors 31 and 32 may be formed of a material containing Cr (chromium), a material containing Ni (nickel), or a material containing both Cr and Ni, for example. That is, the resistors 31 and 32 may be formed of a material including at least one of Cr and Ni. Examples of the material containing Cr include a Cr mixed phase film. Examples of the material containing Ni include Cu — Ni (copper nickel). Examples of the material containing both Cr and Ni include Ni — Cr (nickel chromium).

The Cr mixed phase film is formed of Cr, CrN, and Cr₂N, etc. are mixedAnd (3) a film obtained by the synthesis. The Cr mixed phase film may contain inevitable impurities such as chromium oxide.

The thickness of the resistors 31 and 32 is not particularly limited, and may be appropriately selected according to the purpose, and may be, for example, about 0.05 μm to 2 μm. In particular, the thickness of the resistors 31 and 32 is preferably 0.1 μm or more from the viewpoint of improving the crystallinity of the crystal constituting the resistors 31 and 32 (for example, the crystallinity of α — Cr), and more preferably 1 μm or less from the viewpoint of reducing film cracks or warpage from the substrate 10 due to internal stress of the films constituting the resistors 31 and 32.

For example, when the resistors 31 and 32 are Cr mixed phase films, stability of sensitivity characteristics can be improved by including α -Cr (α -chromium) as a main component, which is a stable crystal phase. Further, by making the resistors 31 and 32 mainly contain α — Cr, the sensitivity (gauge factor) of the strain gauge 1 can be set to 10 or more, and the temperature coefficient of sensitivity TCS and the temperature coefficient of resistance TCR can be set to a range of-1000 ppm/° c to +1000ppm/° c. The main component is a substance that accounts for 50 mass% or more of the total substances constituting the resistors, and from the viewpoint of improving sensitivity characteristics, the resistors 31 and 32 preferably contain 80 mass% or more of α -Cr. α -Cr is Cr having a bcc structure (body-centered cubic lattice structure).

The terminal portions 51 extend from both ends of the resistor body 31 via the wiring patterns 41, are wider than the resistor body 31 in a plan view, and are formed in a substantially rectangular shape. The terminal portions 51 are a pair of electrodes for outputting the change in the resistance value of the resistor 31 due to strain to the outside, and are bonded to, for example, external connection leads or the like. The resistor 31 extends, for example, from one terminal 51 in a zigzag shape via the wiring pattern 41, is folded back, and is connected to the other terminal 51 via the wiring pattern 41.

The terminal portions 52 extend from both ends of the resistor 32 via the wiring patterns 42, are wider than the resistor 32 in a plan view, and are formed in a substantially rectangular shape. The terminal portions 52 are a pair of electrodes for outputting the change in the resistance value of the resistor 32 due to strain to the outside, and are bonded to, for example, external connection leads or the like. The resistor 32 extends, for example, from one terminal 52 in a zigzag shape via the wiring pattern 42, is folded back, and is connected to the other terminal 52 via the wiring pattern 42.

The upper surfaces of the terminal portions 51 and 52 may be covered with a metal having better solderability than the terminal portions 51 and 52. Note that although different symbols are given to the resistor bodies 31 and 32, the wiring patterns 41 and 42, and the terminal portions 51 and 52 for convenience, they may be integrally formed of the same material in the same process.

A cover layer 61 (insulating resin layer) may be provided on the upper surface 10a of the base material 10 so as to cover the resistor 31 and expose the terminal portions 51. By providing the cover layer 61, it is possible to prevent mechanical damage and the like from occurring on the resistor 31. Further, by providing the cover layer 61, the resistor 31 can be protected from moisture and the like. Note that the cover layer 61 may be provided to cover a wider area except for the terminal portion 51.

A cover layer 62 (insulating resin layer) may be provided on the upper surface 10a of the base material 10 so as to cover the resistor 32 and expose the terminal portions 52. By providing the cover layer 62, it is possible to prevent mechanical damage and the like from occurring on the resistor 32. Further, by providing the cover layer 62, the resistor 32 can be protected from moisture and the like. Note that the cover layer 62 may be provided to cover a wider area except for the terminal portion 52.

The cover layers 61 and 62 may be formed of an insulating resin such as PI resin, epoxy resin, PEEK resin, PEN resin, PET resin, PPS resin, or composite resin (e.g., silicone resin or polyolefin resin). The covering layers 61 and 62 may contain a filler or a pigment. The thickness of the covering layers 61 and 62 is not particularly limited and may be appropriately selected according to the purpose, and may be, for example, about 2 μm to 30 μm.

Fig. 3 is a perspective view showing a sensor module according to embodiment 1. Fig. 4 is a sectional view showing a sensor module according to embodiment 1, showing a longitudinal section along line B-B of fig. 3. In fig. 2 and 4, the dimensional ratios of the respective members are changed for convenience.

As shown in fig. 1 to 4, the base material 10 of the strain gauge 1 has a first region E1 that can be pasted on the first surface S1 of the flexure 110, and a second region E2 and a third region E3 that can be pasted on the second surface S2 and the third surface S3 of the flexure 110 adjacent to the first surface S1 and opposed to each other.

In the strain gauge 1, the terminal portions 51 and 52 as electrodes are arranged in the first region E1. In the strain sheet 1, the resistor 31 is disposed in the second region E2, and the resistor 32 is disposed in the third region E3. In the strain gauge 1, the resistor 31 and the resistor 32 are arranged so as to be opposed to each other with the flexure body 110 interposed therebetween when the base material 10 is pasted to the flexure body 110.

The sensor module 5 includes a strain gauge 1, a flexure 110, and an adhesive layer 120. In the sensor module 5, the substrate 10 is adhered to the surface of the flexure 110 via the adhesive layer 120. More specifically, the first region E1 of the substrate 10 is adhered to the first surface S1 of the flexure 110 via the adhesive layer 120, the second region E2 is adhered to the second surface S2 via the adhesive layer 120, and the third region E3 is adhered to the third surface S3 via the adhesive layer 120.

That is, in the sensor module 5, the terminal portions 51 and 52 as electrodes are arranged on the first surface S1 of the flexure body 110, the resistor 31 is arranged on the second surface S2 of the flexure body 110, and the resistor 32 is arranged on the third surface S3 of the flexure body 110. The resistor 31 disposed on the second surface S2 and the resistor 32 disposed on the third surface S3 are opposed to each other with the flexure body 110 interposed therebetween.

Note that, although the terminal portions 51 and 52 are arranged in the first region E1 in the example of fig. 1 to 4, the terminal portion 51 may be arranged in the second region E2 and the terminal portion 52 may be arranged in the third region E3. However, from the viewpoint of improving workability, it is preferable to dispose the terminal portions 51 and 52 in the first region E1. This is because, by disposing the terminal portions 51 and 52 in the first region E1, the terminal portions 51 and 52 can be connected to the lead wires or the like only on the same surface (first surface S1) of the sensor module 5.

The flexure 110 is formed of, for example, metal such as Fe, SUS (stainless steel), Al, or resin such as PEEK, and deforms (generates strain) in response to an applied force. The strain gauge 1 can detect the strain generated in the flexure 110 as a change in the resistance values of the resistors 31 and 32.

The material of the adhesive layer 120 is not particularly limited as long as it has a function of adhering the strain gauge 1 and the flexure 110 together, and may be appropriately selected according to the purpose, and for example, an epoxy resin, a modified epoxy resin, a silicone resin, a modified silicone resin, a urethane resin, a modified urethane resin, or the like may be used. Further, a material such as an adhesive sheet may be used. The thickness of the adhesive layer 120 is not particularly limited and may be appropriately selected according to the purpose, and may be, for example, about 0.1 μm to 50 μm.

To manufacture the strain gauge 1, first, a substrate 10 is prepared, and a metal layer (for convenience, referred to as a metal layer 300) to be finally patterned into the resistor bodies 31 and 32, the wiring patterns 41 and 42, and the terminal portions 51 and 52 is formed on the entire upper surface 10a of the substrate 10. The material and thickness of the metal layer 300 are the same as those of the above-described resistor bodies 31 and 32, wiring patterns 41 and 42, and terminal portions 51 and 52.

The metal layer 300 can be formed, for example, by magnetron sputtering using a material capable of forming the metal layer 300 as a target. The metal layer 300 may be formed by a reactive sputtering method, a vapor deposition method, an arc ion plating method, a pulsed laser deposition method, or the like, instead of the magnetron sputtering method.

From the viewpoint of stabilizing the sensitivity characteristics, it is preferable that before the deposition of the metal layer 300, a functional layer having a thickness of about 1nm to 100nm is vacuum-deposited as an underlayer on the upper surface 10a of the substrate 10 by, for example, a conventional sputtering method.

In the present application, the functional layer is a layer having at least a function of promoting crystal growth of the upper resistors 31 and 32 (after the metal layer 300 is patterned). The functional layer preferably further has a function of preventing the resistors 31 and 32 from being oxidized by oxygen or moisture contained in the base 10 and a function of improving the adhesion between the base 10 and the resistors 31 and 32. The functional layer may also have other functions.

Since the insulating resin film constituting the substrate 10 contains oxygen or moisture, particularly when the resistors 31 and 32 contain Cr, since Cr forms an autoxidation film, it is effective to provide the functional layer with a function of preventing the resistors 31 and 32 from being oxidized.

The material of the functional layer is not particularly limited as long as it has at least a function of promoting crystal growth of the upper resistors 31 and 32, examples of the metal include one or more metals selected from the group consisting of Cr (chromium), Ti (titanium), V (vanadium), Nb (niobium), Ta (tantalum), Ni (nickel), Y (yttrium), Zr (zirconium), Hf (hafnium), Si (silicon), C (carbon), Zn (zinc), Cu (copper), Bi (bismuth), Fe (iron), Mo (molybdenum), W (tungsten), Ru (ruthenium), Rh (rhodium), Re (rhenium), Os (osmium), Ir (iridium), Pt (platinum), Pd (palladium), Ag (silver), Au (gold), Co (cobalt), Mn (manganese), and Al (aluminum), an alloy of any of the metals in the group, and a compound of any of the metals in the group.

Examples of the alloy include FeCr, TiAl, FeNi, NiCr, and CrCu. Examples of the compound include TiN, TaN, and Si₃N₄、TiO₂、Ta₂O₅、SiO₂And the like.

The functional layer can be vacuum-deposited by, for example, a conventional sputtering method in which a raw material capable of forming the functional layer is used as a target and Ar (argon) gas is introduced into a chamber. By using the conventional sputtering method, the functional layer can be formed while etching the upper surface 10a of the base material 10 with Ar, and therefore the film formation amount of the functional layer can be minimized to obtain the effect of improving the adhesion.

However, this is only one example of a method for forming a functional layer, and the functional layer may be formed by another method. For example, a method of activating the upper surface 10a of the substrate 10 by plasma treatment using Ar or the like to obtain an effect of improving adhesion before the film formation of the functional layer, and then performing vacuum film formation of the functional layer by a magnetron sputtering method may be used.

The combination of the material of the functional layer and the material of the metal layer 300 to be the resistors 31 and 32 and the like is not particularly limited, and may be appropriately selected according to the purpose, and for example, Ti may be used as the functional layer, and a Cr mixed phase film containing α -Cr (α -chromium) as a main component may be formed as the metal layer 300.

In this case, the metal layer 300 may be formed by, for example, a magnetron sputtering method in which a raw material capable of forming a Cr mixed phase film is used as a target and Ar gas is introduced into a chamber. Alternatively, the metal layer 300 may be formed by a reactive sputtering method by introducing Ar gas and an appropriate amount of nitrogen gas into a chamber using pure Cr as a target.

In these methods, a Cr mixed phase film having α — Cr as a main component, which is a stable crystal structure, can be formed while restricting the growth surface of the Cr mixed phase film with the functional layer made of Ti as the starting point. Further, the sensitivity characteristics are improved by diffusing Ti constituting the functional layer into the Cr mixed phase film. For example, the sensitivity of the strain gauge 1 can be set to 10 or more, and the temperature coefficient of sensitivity TCS and the temperature coefficient of resistance TCR can be set to a range of-1000 ppm/DEG C to +1000 ppm/DEG C. When the functional layer is formed of Ti, Ti or TiN (titanium nitride) may be contained in the Cr mixed phase film.

When the resistors 31 and 32 are Cr mixed phase films, the functional layer made of Ti has all of a function of promoting crystal growth of the resistors 31 and 32, a function of preventing oxidation of the resistors 31 and 32 by oxygen or moisture contained in the substrate 10, and a function of improving adhesion between the substrate 10 and the resistors 31 and 32. The same applies to the case where Ta, Si, Al, Fe is used as the functional layer instead of Ti.

By providing the functional layer below the resistors 31 and 32 in this way, crystal growth of the resistors 31 and 32 can be promoted, and the resistors 31 and 32 formed of a stable crystal phase can be manufactured. Therefore, the strain gauge 1 can improve the stability of the sensitivity characteristic. Further, by diffusing the material constituting the functional layer into the resistors 31 and 32, the sensitivity characteristics can be improved in the strain gauge 1.

After forming the functional layer and the metal layer 300 on the entire upper surface 10a of the substrate 10, the functional layer and the metal layer 300 formed on the entire upper surface 10a of the substrate 10 are patterned into the shape of fig. 1 by photolithography. Thereby, the resistor bodies 31 and 32, the wiring patterns 41 and 42, and the terminal portions 51 and 52 are formed.

After the resistor bodies 31 and 32, the wiring patterns 41 and 42, and the terminal portions 51 and 52 are formed, the strain gauge 1 is completed by providing, on the upper surface 10a of the base material 10, a coating layer 61 that covers the resistor body 31 and exposes the terminal portions 51 and a coating layer 62 that covers the resistor body 32 and exposes the terminal portions 52, as necessary. The cover layers 61 and 62 can be produced by, for example, laminating a thermosetting insulating resin film in a semi-cured state on the upper surface 10a of the base material 10 so as to cover the resistor 31 and expose the terminal portions 51, and cover the resistor 32 and expose the terminal portions 52, and heating and curing the resin film. The covering layers 61 and 62 may be prepared by applying a liquid or paste thermosetting insulating resin on the upper surface 10a of the base material 10 so as to cover the resistor 31 and expose the terminal portions 51, and cover the resistor 32 and expose the terminal portions 52, and heating and curing the resin.

When functional layers are provided as the base layers of the resistors 31 and 32, the wiring patterns 41 and 42, and the terminal portions 51 and 52 on the upper surface 10a of the base 10, the strain gauge 1 has a cross-sectional shape as shown in fig. 5. The layer denoted by the symbol 20 is a functional layer. The planar shape of the strain gauge 1 in the case where the functional layer 20 is provided is the same as that of fig. 1.

In order to manufacture the sensor module 5, after the strain gauge 1 is manufactured, the base material 10 of the strain gauge 1 is stuck to the flexure 110. Specifically, for example, the lower surface of the base material 10 and/or the surface of the flexure 110 (predetermined regions of the first surface S1, the second surface S2, and the third surface S3) are coated with any of the above-described materials to be the adhesive layer 120, for example. Next, the lower surface of the base material 10 is opposed to the surface of the flexure 110, and the strain gauge 1 is disposed on the flexure 110 with the material applied therebetween. Alternatively, an adhesive sheet may be sandwiched between flexure 110 and substrate 10.

Next, the strain gauge 1 is heated to a predetermined temperature while being pressed toward the flexure 110 side, and the applied material is cured to form the adhesive layer 120. Thereby, the surface of the flexure 110 and the lower surface of the substrate 10 are adhered together via the adhesive layer 120, and the sensor module 5 is completed. The sensor module 5 can be used for measuring load, pressure, torque, acceleration, and the like, for example.

As described above, in the sensor module 5, the resistor body 31 and the resistor body 32 are arranged at opposite positions with the flexure body 110 interposed therebetween. Therefore, for example, in the case where bending stress is generated in which the second surface S2 of the flexure body 110 is a tensile side and the third surface S3 is a compressive side, the output of the terminal portion 51 connected to the resistor body 31 arranged on the second surface S2 and the output of the terminal portion 52 connected to the resistor body 32 arranged on the third surface S3 have equal absolute values and opposite signs. Therefore, the detection sensitivity can be improved when the output of the terminal unit 51 and the output of the terminal unit 52 are connected to a Wheatstone bridge (Wheatstone bridge) to detect strain.

Further, by using one strain gauge 1 in which a plurality of resistors are patterned, the efficiency of the attaching work can be improved as compared with a case where a plurality of strain gauges are used and individually attached to the flexure 110. Further, by using the strain gauge 1, the number of parts of the sensor module 5 can be reduced and the reliability of the sensor module 5 can be improved, compared to a case where a plurality of strain gauges are used and individually attached to the flexure 110.

< modification 1 of embodiment 1>

In modification 1 of embodiment 1, an example of a strain gauge and a sensor module having four resistor bodies is shown. In modification 1 of embodiment 2, the same components as those of the above-described embodiment may be omitted from the description.

Fig. 6 is a plan view showing a strain gauge according to modification 1 of embodiment 1. Fig. 7 is a perspective view showing a sensor module according to modification 1 of embodiment 1. Since the cross-sectional shapes of the strain gauge and the sensor module according to modification 1 of embodiment 1 are the same as those of fig. 2 and 4, the cross-sectional shapes are not shown.

As shown in fig. 6, the strain gauge 1A has a base material 10X having a cross-shaped planar shape. On the substrate 10X, the resistor 31, the wiring pattern 41, the terminal portion 51, the resistor 32, the wiring pattern 42, and the terminal portion 52 are provided in the same arrangement as the strain gauge 1. Further, the resistor 33, the wiring pattern 43, the terminal portion 53, the resistor 34, the wiring pattern 44, and the terminal portion 54 are provided on the substrate 10X.

The resistors 33 and 34 are sensing portions formed on the substrate 10X and subjected to strain to cause a change in resistance. The resistors 33 and 34 may be arranged on the substrate 10X such that the grid directions are oriented in the same direction, for example. The resistors 33 and 34 and the resistors 31 and 32 may be arranged on the substrate 10X such that the grid direction is oriented in a direction perpendicular to the grid direction, for example. The material and thickness of the base 10X and the resistors 33 and 34 may be the same as those of the base 10 and the resistors 31 and 32, for example. In fig. 6, the resistors 31, 32, 33, and 34 are shown in a hatched pattern for convenience.

The terminal portions 53 extend from both ends of the resistor body 33 via the wiring patterns 43, are wider than the resistor body 33 in a plan view, and are formed in a substantially rectangular shape. The terminal portions 53 are a pair of electrodes for outputting the change in the resistance value of the resistor 33 due to strain to the outside, and are bonded to, for example, external connection leads or the like. The resistor 33 extends, for example, from one terminal 53 in a zigzag shape via the wiring pattern 43, is folded back, and is connected to the other terminal 53 via the wiring pattern 43.

The terminal portions 54 extend from both ends of the resistor body 34 via the wiring patterns 44, are wider than the resistor body 34 in a plan view, and are formed in a substantially rectangular shape. The terminal portions 54 are a pair of electrodes for outputting the change in the resistance value of the resistor 34 caused by the change in the resistance to the outside, and are bonded to, for example, external connection leads. The resistor 34 extends, for example, from one terminal 54 in a zigzag shape via the wiring pattern 44, is folded back, and is connected to the other terminal 54 via the wiring pattern 44.

The upper surfaces of the terminal portions 53 and 54 may be covered with a metal having better solderability than the terminal portions 53 and 54. Note that, although the resistors 31, 32, 33, and 34, the wiring patterns 41, 42, 43, and 44, and the terminal portions 51, 52, 54, and 54 are given different symbols for convenience, they may be integrally formed of the same material in the same process.

A cover layer 63 (insulating resin layer) may be provided on the upper surface 10a of the base 10X so as to cover the resistor 33 and expose the terminal portions 53. By providing the cover layer 63, it is possible to prevent mechanical damage and the like from occurring on the resistor 33. Further, by providing the cover layer 63, the resistor 33 can be protected from moisture and the like. Note that the cover layer 63 may be provided to cover a wider area except for the terminal portion 53.

A cover layer 64 (insulating resin layer) may be provided on the upper surface 10a of the base 10X so as to cover the resistor 34 and expose the terminal portions 54. By providing the cover layer 64, it is possible to prevent mechanical damage and the like from occurring on the resistor 34. Further, by providing the cover layer 64, the resistor 34 can be protected from moisture and the like. Note that the cover layer 64 may be provided to cover a wider area other than the terminal portion 54. The material and thickness of the covering layers 63 and 64 may be the same as those of the covering layers 61 and 62, for example.

As shown in fig. 6 and 7, the base material 10X of the strain gauge 1A has a first region E1 that can be pasted on the first surface S1 of the flexure 110, a second region E2 and a third region E3 that can be pasted on the second surface S2 and the third surface S3 of the flexure 110 adjacent to the first surface S1 and opposed to each other, and a fourth region E4 and a fifth region E5 that can be pasted on the fourth surface S4 and the fifth surface S5 of the flexure 110 adjacent to the first surface S1 and opposed to each other.

In the strain gauge 1A, the terminal portions 51, 52, 53, and 54 as electrodes are arranged in the first region E1. In the strain sheet 1A, the resistor 31 is disposed in the second region E2, the resistor 32 is disposed in the third region E3, the resistor 33 is disposed in the fourth region E4, and the resistor 34 is disposed in the fifth region E5. In the strain gauge 1A, the resistor 31 and the resistor 32 are arranged so as to be opposed to each other with the flexure body 110 interposed therebetween when the substrate 10X is attached to the flexure body 110, and the resistor 33 and the resistor 34 are arranged so as to be opposed to each other with the flexure body 110 interposed therebetween when the substrate 10X is attached to the flexure body 110.

The sensor module 5A includes a strain gauge 1A, a flexure 110, and an adhesive layer 120. In the sensor module 5A, the base material 10X is adhered to the surface of the flexure 110 via the adhesive layer 120. More specifically, the first region E1 of the substrate 10X is adhered to the first surface S1 of the flexure 110 via the adhesive layer 120, the second region E2 is adhered to the second surface S2 via the adhesive layer 120, the third region E3 is adhered to the third surface S3 via the adhesive layer 120, the fourth region E4 is adhered to the fourth surface S4 via the adhesive layer 120, and the fifth region E5 is adhered to the fifth surface S5 via the adhesive layer 120.

That is, in the sensor module 5A, the terminal portions 51, 52, 53, and 54 as the electrodes are arranged on the first surface S1 of the flexure body 110, the resistor 31 is arranged on the second surface S2 of the flexure body 110, the resistor 32 is arranged on the third surface S3 of the flexure body 110, the resistor 33 is arranged on the fourth surface S4 of the flexure body 110, and the resistor 34 is arranged on the fifth surface S5 of the flexure body 110. The resistor 31 disposed on the second surface S2 and the resistor 32 disposed on the third surface S3 are opposed to each other with the flexure body 110 interposed therebetween. In addition, the resistor body 33 disposed on the fourth surface S4 and the resistor body 34 disposed on the fifth surface S5 are opposed to each other with the flexure body 110 interposed therebetween.

As described above, in the sensor module 5A, the resistor body 31 and the resistor body 32 are arranged at opposite positions so as to sandwich the flexure body 110. Therefore, for example, in the case where bending stress is generated in which the second surface S2 of the flexure body 110 is a tensile side and the third surface S3 is a compressive side, the output of the terminal portion 51 connected to the resistor body 31 arranged on the second surface S2 and the output of the terminal portion 52 connected to the resistor body 32 arranged on the third surface S3 have equal absolute values and opposite signs. Therefore, the detection sensitivity in the case of performing strain detection by connecting the output of the terminal portion 51 and the output of the terminal portion 52 to the wheatstone bridge can be improved.

Likewise, in the sensor module 5A, the resistor body 33 and the resistor body 34 are arranged at opposite positions with the flexure body 110 interposed therebetween. Therefore, for example, in the case where bending stress is generated in which the fourth surface S4 of the flexure body 110 is a tensile side and the fifth surface S5 is a compression side, the output of the terminal portion 53 connected to the resistor body 33 arranged on the fourth surface S4 and the output of the terminal portion 54 connected to the resistor body 34 arranged on the fifth surface S5 have equal absolute values and opposite signs. Therefore, the detection sensitivity in the case of performing strain detection by connecting the output of the terminal portion 53 and the output of the terminal portion 54 to the wheatstone bridge can be improved.

Further, by using one strain gauge 1A in which a plurality of resistors are patterned, the efficiency of the attaching work can be improved as compared with a case where a plurality of strain gauges are used and individually attached to the flexure 110. Further, by using the strain gauge 1A, the number of parts of the sensor module 5A can be reduced and the reliability of the sensor module 5A can be improved, compared to a case where a plurality of strain gauges are used and individually attached to the flexure 110.

While the preferred embodiments and the like have been described in detail, the present invention is not limited to the above embodiments and the like, and various modifications and substitutions can be made thereto without departing from the scope of the claims.

For example, embodiment 1 shows an example of a strain gauge having two resistor bodies, and modification 1 of embodiment 1 shows an example of a strain gauge having four resistor bodies. However, the strain gauge according to the present invention may have any number of resistor bodies as long as it includes at least two resistor bodies arranged so as to be opposed to each other with the flexure body interposed therebetween when the base material is bonded to the flexure body.

In addition, embodiment 1 shows an example of a strain gauge having a base material whose planar shape is a belt shape, and variation 1 of embodiment 1 shows an example of a strain gauge having a base material whose planar shape is a cross shape. However, the planar shape of the base material may be any shape as long as the strain gauge according to the present invention includes at least two resistor bodies arranged so as to be opposed to each other with the flexure body interposed therebetween when the base material is stuck on the flexure body. Therefore, the shape of the flexible member is not limited to a simple planar shape such as a band or a cross, and may be a more complex planar shape matching the shape of the flexible member.

The international application takes the Japanese invention patent application No. 2017-254442 filed on 12/28 in 2017 as the basis for priority, and the international application refers to the entire contents of the Japanese invention patent application No. 2017-254442.

Description of the symbols

1. 1A strain gauge; 5. 5A sensor module; 10. a 10X substrate; 10a upper surface; 20 functional layers; 31. 32, 33, 34 resistors; 41. 42, 43, 44 wiring patterns; 51. 52, 53, 54 terminal portions; 61. 62, 63, 64 cover layers; 110 a flexure; 120 adhesive layer.