Sensor Module

Abstract

The sensor module is made smaller. [Solution] This sensor module comprises a flexible resin substrate, a functional layer formed directly on one side of the substrate from a metal, alloy, or metal compound, a resistor whose main component is α-Cr and formed from a film containing Cr, CrN, and Cr2N directly on one side of the functional layer, an electronic component mounted on one side of the substrate and electrically connected to the resistor, and a power source mounted on one or the other side of the substrate and electrically connected to the electronic component to supply power to the electronic component, wherein the functional layer has the function of promoting crystal growth of the α-Cr and forming a film whose main component is α-Cr, the thickness of the resistor is 0.05 μm or more and 2 μm or less, and the thickness of the functional layer is 1 nm or more and 100 nm or less.

Description

[Technical Field]

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

[0002] Strain gauges are known that are attached to a measurement object to detect strain on the object. The strain gauge includes a resistor that detects strain, and the resistor is made of, for example, a material containing Cr (chromium) or Ni (nickel). Furthermore, for example, both ends of the resistor are used as electrodes, and lead wires for external connection are joined to the electrodes by soldering, enabling signal input and output with electronic components (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-74934 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, the electronic components connected to the strain gauge resistor and the power supply that supplies power to the electronic components were installed outside the strain gauge to form a sensor module, which made it difficult to miniaturize the sensor module.

[0005] The present invention has been made in view of the above points, and has an object to reduce the size of a sensor module. [Means for solving the problem]

[0006] This sensor module comprises a flexible resin substrate, a functional layer formed directly on one side of the substrate from a metal, alloy, or metal compound, a resistor whose main component is α-Cr and formed from a film containing Cr, CrN, and CrN directly on one side of the functional layer, an electronic component mounted on one side of the substrate and electrically connected to the resistor, and a power source mounted on one or the other side of the substrate and electrically connected to the electronic component to supply power to the electronic component, wherein the functional layer has the function of promoting crystal growth of the α-Cr and forming a film whose main component is α-Cr, the thickness of the resistor is 0.05 μm or more and 2 μm or less, and the thickness of the functional layer is 1 nm or more and 100 nm or less. [Effects of the Invention]

[0007] According to the disclosed technology, the sensor module can be made smaller. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a partial plan view illustrating the sensor module according to the first embodiment. [Figure 2] 1 is a cross-sectional view illustrating a sensor module according to a first embodiment. [Figure 3] FIG. 10 is a cross-sectional view illustrating a sensor module according to a first modification of the first embodiment. [Figure 4] FIG. 10 is a cross-sectional view illustrating a sensor module according to a second modification of the first embodiment. [Figure 5] FIG. 10 is a cross-sectional view illustrating a sensor module according to a third modification of the first embodiment. [Figure 6] FIG. 10 is a cross-sectional view illustrating a sensor module according to a fourth modification of the first embodiment. [Figure 7] 13 is a partial plan view (part 1) illustrating a sensor module according to a fifth modified example of the first embodiment. FIG. [Figure 8] 13 is a partial plan view (part 2) illustrating a sensor module according to a fifth modification of the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations may be omitted.

[0010] First Embodiment Fig. 1 is a partial plan view illustrating a sensor module according to a first embodiment. Fig. 1 is an enlarged view of the area from resistor 30 to electronic component 200 in Fig. 2, and does not show cover layer 60, wiring pattern 70, and solar cell 300. Fig. 2 is a cross-sectional view illustrating the sensor module according to the first embodiment, taken along line AA in Fig. 1.

[0011] 1 and 2, the sensor module 5 includes a substrate 10, a resistor 30, a wiring pattern 40, an electrode 40A, an electronic component 200, metal wires 210 and 220, a wiring pattern 50, an electrode 50A, a cover layer 60, a wiring pattern 70, a solar cell 300, a strain element 510, and an adhesive layer 520. In the sensor module 5, the portion including the substrate 10, the resistor 30, the wiring pattern 40, and the electrode 40A constitutes a strain gauge.

[0012] In this embodiment, for convenience, in the sensor module 5, the side of the substrate 10 on which the resistor 30 is provided is referred to as the upper side or one side, and the side on which the resistor 30 is not provided is referred to as the lower side or the other side. Furthermore, the surface on which the resistor 30 is provided in each portion is referred to as the one side or upper side, and the surface on which the resistor 30 is not provided is referred to as the other side or lower side. However, the sensor module 5 can be used upside down or placed at any angle. Furthermore, a planar view refers to viewing an object from the normal direction of the upper surface 10a of the substrate 10, and a planar shape refers to the shape of the object viewed from the normal direction of the upper surface 10a of the substrate 10.

[0013] The substrate 10 is a flexible member that serves as a base layer for forming the resistor 30 and the like. The thickness of the substrate 10 is not particularly limited and can be appropriately selected depending on the purpose, but can be, for example, about 5 μm to 500 μm. In particular, a thickness of 5 μm to 200 μm is preferable in terms of the transferability of strain from the surface of the flexure element 510 joined to the lower surface 10b of the substrate 10 via the adhesive layer 520 and dimensional stability against the environment, and a thickness of 10 μm or more is even more preferable in terms of insulation.

[0014] The substrate 10 can be formed from 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, polyolefin resin, etc. The film refers to a flexible member having a thickness of about 500 μm or less.

[0015] Here, "formed from an insulating resin film" does not prevent the base material 10 from containing fillers, impurities, etc. in the insulating resin film. The base material 10 may be formed from an insulating resin film containing fillers such as silica or alumina, for example.

[0016] However, if the substrate 10 does not need to be flexible, the substrate 10 may be made of materials such as SiO2, ZrO2 (including YSZ), Si, Si2N3, Al2O3 (including sapphire), ZnO, perovskite ceramics (CaTiO3, BaTiO3), etc.

[0017] The resistor 30 is a thin film formed in a predetermined pattern on the substrate 10, and is a sensing part that generates a resistance change when strain is applied. The resistor 30 may be formed directly on the upper surface 10a of the substrate 10, or may be formed on the upper surface 10a of the substrate 10 via another layer. For convenience, the resistor 30 is shown in FIG. 1 with a matte finish.

[0018] The resistor 30 can be formed from, for example, a material containing Cr (chromium), a material containing Ni (nickel), or a material containing both Cr and Ni. That is, the resistor 30 can be formed from a material containing at least one of Cr and Ni. An example of a material containing Cr is a Cr mixed phase film. 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).

[0019] Here, the Cr mixed phase film is a film containing a mixture of Cr, CrN, Cr2N, etc. The Cr mixed phase film may contain inevitable impurities such as chromium oxide.

[0020] The thickness of resistor 30 is not particularly limited and can be appropriately selected depending on the purpose, but can be, for example, about 0.05 μm to 2 μm. In particular, a thickness of resistor 30 of 0.1 μm or more is preferable because it improves the crystallinity of the crystals constituting resistor 30 (for example, the crystallinity of α-Cr), and a thickness of 1 μm or less is even more preferable because it reduces cracks in the film constituting resistor 30 and warpage from substrate 10 caused by internal stress in the film.

[0021] For example, when the resistor 30 is a Cr mixed-phase film, the stability of the gauge characteristics can be improved by using α-Cr (alpha chromium), which has a stable crystalline phase, as the main component. Furthermore, by using α-Cr as the main component of the resistor 30, the gauge factor of the strain gauge included in the sensor module 5 can be 10 or more, and the temperature coefficient of gauge factor (TCS) and temperature coefficient of resistance (TCR) can be within the range of −1000 ppm / °C to +1000 ppm / °C. Here, “main component” means that the target substance accounts for 50 mass% or more of all materials constituting the resistor. From the viewpoint of improving the gauge characteristics, however, it is preferable that the resistor 30 contains α-Cr at 80 wt% or more. Note that α-Cr is Cr with a bcc structure (body-centered cubic lattice structure).

[0022] The wiring pattern 40 is a pair of wiring patterns electrically connected to both ends of the resistor 30. The wiring pattern 40 has a first layer 41 and a second layer 42 laminated on the first layer 41. The first layer 41 extends from both ends of the resistor 30 and is formed in a generally rectangular shape wider than the resistor 30 in a plan view. The second layer 42 is laminated on the top surface of the first layer 41. For example, the resistor 30 extends from one side of the wiring pattern 40 while folding back in a zigzag pattern and is connected to the other side of the wiring pattern 40. The wiring pattern 40 is not limited to a linear shape and can be any pattern. Furthermore, the wiring pattern 40 can have any width and length.

[0023] The electrodes 40A are electrically connected to the respective wiring patterns 40. The electrodes 40A are a pair of electrodes for outputting a change in the resistance value of the resistor 30 caused by strain, and are electrically connectable to the electronic component 200. The electrodes 40A may be formed to have a width different from that of the wiring patterns 40.

[0024] Although the resistor 30 and the first layer 41 are denoted by different reference numerals for convenience, they can be integrally formed from the same material in the same process.

[0025] The second layer 42 has a lower resistance than the first layer 41. The material of the second layer 42 is not particularly limited and can be appropriately selected depending on the purpose as long as it has a lower resistance than the first layer 41, and examples of materials that can be used include Cu, a Cu alloy, Ni, and a Ni alloy. The thickness of the second layer 42 can be, for example, about 0.5 μm to 30 μm.

[0026] The second layer 42 may be a laminated film. Examples of laminated films include Cu / Ni / Au, Cu / NiP / Au, Cu / Pd / Au, Cu / Pt / Au, Ni / Au, and NiP / Au. Note that "AA / BB" refers to a laminated film in which an AA layer and a BB layer are laminated in that order on the upper surface of a lower layer (the same applies to three or more layers). In these laminated films, a Cu alloy may be used instead of Cu, and a Ni alloy may be used instead of Ni.

[0027] Although the wiring pattern 40 and the electrode 40A are given different reference numerals for convenience, they can be integrally formed from the same material in the same process. However, the layer structure of the electrode 40A may be different from that of the wiring pattern 40. For example, Au or the like may be formed only on the top layer of the electrode 40A to improve connection reliability.

[0028] By selecting the material of the second layer 42 in this way, it is possible to improve the reliability of connection with the electronic component without relying on the material of the first layer 41, which is the same material as the resistor 30.

[0029] The electronic component 200 is mounted on the upper surface 10a of the substrate 10 via, for example, an adhesive layer such as a die attach film. The electronic component 200 is, for example, a semiconductor chip that amplifies and temperature compensates for an electrical signal input from the resistor 30 via the wiring pattern 40 and the electrode 40A. Passive components such as a capacitor may also be mounted together with the semiconductor chip.

[0030] Alternatively, electronic component 200 may be flip-chip mounted on top surface 10a of substrate 10. In this case, wiring pattern 40 may be rerouted so that electrode 40A is disposed on the underside of electronic component 200, and electrode 40A and electrode 200A formed on the underside of electronic component 200 may be connected using a solder ball or the like.

[0031] In addition, an external input / output terminal can be provided at any position on the upper surface 10a of the substrate 10, which can be electrically connected to the electronic component 200 and enables signal input / output with an external circuit electrically connected to the sensor module 5.

[0032] Electronic component 200 has electrode 200A connected to resistor 30 and electrode 200B to which power is supplied. Electrode 200A of electronic component 200 is electrically connected to electrode 40A via metal wire 210 such as a gold wire or a copper wire. Electrode 200A and electrode 40A can be connected by wire bonding, for example.

[0033] Electrode 200B of electronic component 200 is electrically connected to electrode 50A via metal wire 220, such as gold wire or copper wire. Electrode 200B and electrode 50A can be connected by, for example, wire bonding. Wiring pattern 50 is connected to electrode 50A. Similar to wiring pattern 40, wiring pattern 50 has a first layer 41 and a second layer 42 laminated on first layer 41. Wiring pattern 50 is not limited to a linear shape and can have any pattern. Furthermore, wiring pattern 50 can have any width and length.

[0034] The cover layer 60 is an insulating resin layer provided on the upper surface 10a of the substrate 10 so as to cover the resistor 30, the wiring pattern 40, the electrode 40A, the electronic component 200, the metal wires 210 and 220, the electrode 50A, and the wiring pattern 50. However, the end of the wiring pattern 50 opposite to the electrode 50A is exposed from the cover layer 60.

[0035] The provision of the cover layer 60 can prevent mechanical damage and the like from occurring to the resistor 30, the wiring pattern 40, the electrode 40A, the electronic component 200, the metal wires 210 and 220, the electrode 50A, and the wiring pattern 50. The provision of the cover layer 60 can also protect the resistor 30, the wiring pattern 40, the electrode 40A, the electronic component 200, the metal wires 210 and 220, the electrode 50A, and the wiring pattern 50 from moisture and the like.

[0036] The cover layer 60 can be formed from 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 cover layer 60 may contain a filler or a pigment. There are no particular restrictions on the thickness of the cover layer 60 and it can be appropriately selected depending on the purpose, but it can be, for example, about 2 μm to 30 μm.

[0037] The solar cell 300 is mounted on the upper surface 10a side of the base material 10. Specifically, the solar cell 300 is disposed on the upper surface of the cover layer 60, and is electrically connected to the wiring pattern 50 via the wiring pattern 70 provided on the side surface of the cover layer 60.

[0038] That is, the solar cell 300 is electrically connected to the electrode 200B of the electronic component 200 via the wiring pattern 70, the wiring pattern 50, the electrode 50A, and the metal wire 220, and functions as a power source that supplies power to the electronic component 200.

[0039] The solar cell 300 is, for example, an amorphous silicon-based, silicon crystalline-based, or compound-based (for example, CIGS) flexible solar cell laminated on a cover layer 60. CIGS is a compound-based solar cell whose main components are copper (Cu), indium (In), gallium (Ga), and selenium (Se).

[0040] The method for connecting the solar cells 300 and the wiring pattern 50 is not particularly limited. For example, instead of the wiring pattern 70 provided on the side surface of the cover layer 60, a through-wire that penetrates the cover layer 60 may be provided, and the solar cells 300 and the wiring pattern 50 may be connected via the through-wire. Alternatively, the end of a flexible substrate that constitutes the solar cells 300 may be extended along the side surface of the cover layer 60 and connected to the wiring pattern 50. Alternatively, the solar cells 300 and the wiring pattern 50 may be connected using a wire.

[0041] The flexure element 510 is fixed to the lower surface 10b of the substrate 10 via an adhesive layer 520. The flexure element 510 is an object that is formed from, for example, a metal such as Fe, SUS (stainless steel), or Al, or a resin such as PEEK, and that deforms (generates strain) in response to an applied force. The sensor module 5 can detect the strain generated in the flexure element 510 as a change in the resistance of the resistor 30.

[0042] The adhesive layer 520 is not particularly limited and can be selected appropriately depending on the purpose as long as it has the function of bonding the substrate 10 and the flexure element 510 together, and can be made of, for example, epoxy resin, modified epoxy resin, silicone resin, modified silicone resin, urethane resin, modified urethane resin, etc. Alternatively, a material such as a bonding sheet can be used. The thickness of the adhesive layer 520 is not particularly limited and can be selected appropriately depending on the purpose, and can be, for example, about 0.1 μm to 50 μm.

[0043] To manufacture the sensor module 5, first, a base material 10 is prepared, and then the planar resistor 30 and first layer 41 shown in Fig. 1 are formed on the upper surface 10a of the base material 10. The material and thickness of the resistor 30 and first layer 41 are as described above. The resistor 30 and the first layer 41 can be integrally formed from the same material.

[0044] The resistor 30 and the first layer 41 can be formed, for example, by depositing a film by magnetron sputtering using a target made of a material capable of forming the resistor 30 and the first layer 41, and then patterning the film by photolithography. Instead of magnetron sputtering, the resistor 30 and the first layer 41 may be deposited by reactive sputtering, vapor deposition, arc ion plating, pulsed laser deposition, or the like.

[0045] From the viewpoint of stabilizing the gauge characteristics, it is preferable to vacuum-form a functional layer having a thickness of about 1 nm to 100 nm on the upper surface 10a of the substrate 10 by, for example, conventional sputtering as a base layer before forming the resistor 30 and the first layer 41. After the resistor 30 and the first layer 41 are formed on the entire upper surface of the functional layer, the functional layer is patterned together with the resistor 30 and the first layer 41 into the planar shape shown in FIG.

[0046] In this application, the functional layer refers to a layer having a function of promoting crystal growth of at least the upper layer, the resistor 30. The functional layer preferably also has a function of preventing oxidation of the resistor 30 due to oxygen or moisture contained in the substrate 10, and a function of improving adhesion between the substrate 10 and the resistor 30. The functional layer may also have other functions.

[0047] The insulating resin film that constitutes the substrate 10 contains oxygen and moisture, and since Cr forms a self-oxidized film, it is effective for the functional layer to have the function of preventing oxidation of the resistor 30, especially when the resistor 30 contains Cr.

[0048] The material of the functional layer is not particularly limited as long as it has the function of promoting the crystal growth of at least the upper layer, the resistor 30, and can be appropriately selected depending on the purpose. For example, 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), Examples of suitable metals include one or more metals selected from the group consisting of 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), alloys of any of the metals in this group, and compounds of any of the metals in this group.

[0049] Examples of the alloys include FeCr, TiAl, FeNi, NiCr, CrCu, etc. Examples of the compounds include TiN, TaN, Si3N4, TiO2, Ta2O5, SiO2, etc.

[0050] The functional layer can be formed in vacuum by conventional sputtering, for example, using a target made of a material capable of forming the functional layer and introducing Ar (argon) gas into a chamber. By using conventional sputtering, the functional layer is formed while etching the upper surface 10a of the substrate 10 with Ar, thereby minimizing the amount of the functional layer formed and achieving an improvement in adhesion.

[0051] However, this is just one example of a method for forming the functional layer, and the functional layer may be formed by other methods. For example, a method may be used in which the upper surface 10a of the substrate 10 is activated by plasma treatment using Ar or the like before forming the functional layer, thereby improving adhesion, and then the functional layer is vacuum-formed by magnetron sputtering.

[0052] There are no particular restrictions on the combination of the material of the functional layer with the material of the resistor 30 and the first layer 41, and it can be selected appropriately depending on the purpose. For example, it is possible to use Ti for the functional layer and form a Cr mixed phase film with α-Cr (alpha chromium) as the main component for the resistor 30 and the first layer 41.

[0053] In this case, resistor 30 and first layer 41 can be formed by magnetron sputtering using a target made of a material capable of forming a Cr mixed phase film and introducing Ar gas into a chamber. Alternatively, resistor 30 and first layer 41 can be formed by reactive sputtering using pure Cr as a target and introducing an appropriate amount of nitrogen gas into a chamber together with Ar gas.

[0054] In these methods, the Ti functional layer defines the growth plane of the Cr mixed-phase film, allowing the formation of a Cr mixed-phase film primarily composed of α-Cr, which has a stable crystal structure. Furthermore, the Ti constituting the functional layer diffuses into the Cr mixed-phase film, improving the gauge characteristics. For example, the gauge factor of the strain gauge included in the sensor module 5 can be set to 10 or more, and the temperature coefficient of gauge factor (TCS) and temperature coefficient of resistance (TCR) can be set within the ranges of -1000 ppm / °C to +1000 ppm / °C. When the functional layer is made of Ti, the Cr mixed-phase film may contain Ti or TiN (titanium nitride).

[0055] When the resistor 30 is a Cr mixed phase film, the functional layer made of Ti has all of the following functions: promoting crystal growth of the resistor 30, preventing oxidation of the resistor 30 due to oxygen and moisture contained in the substrate 10, and improving adhesion between the substrate 10 and the resistor 30. The same applies when Ta, Si, Al, or Fe is used as the functional layer instead of Ti.

[0056] In this way, by providing a functional layer below the resistor 30, it is possible to promote crystal growth of the resistor 30, and to produce a resistor 30 consisting of a stable crystalline phase. As a result, it is possible to improve the stability of the gauge characteristics of the strain gauge included in the sensor module 5. Furthermore, by diffusing the material constituting the functional layer into the resistor 30, it is possible to improve the gauge characteristics of the strain gauge included in the sensor module 5.

[0057] After forming the resistor 30 and the first layer 41, the second layer 42 is laminated on the first layer 41. The material and thickness of the second layer 42 are as described above. The second layer 42 can be formed by, for example, electrolytic plating or electroless plating.

[0058] Next, electronic component 200 is mounted via an adhesive layer such as a die attach film at a predetermined position on top surface 10a of substrate 10. Then, for example, by wire bonding, electrode 200A of electronic component 200 is electrically connected to electrode 40A via metal wire 210 such as a gold wire or a copper wire, and electrode 200B of electronic component 200 is electrically connected to electrode 50A via metal wire 220 such as a gold wire or a copper wire.

[0059] Next, a cover layer 60 is formed on the upper surface 10a of the substrate 10 to cover the resistor 30, the wiring pattern 40, the electrode 40A, the electronic component 200, the metal wires 210 and 220, the electrode 50A, and the wiring pattern 50. The material and thickness of the cover layer 60 are as described above. The cover layer 60 can be produced, for example, by laminating a semi-cured thermosetting insulating resin film on the upper surface 10a of the substrate 10 to cover the resistor 30, the wiring pattern 40, the electrode 40A, the electronic component 200, the metal wires 210 and 220, the electrode 50A, and the wiring pattern 50, and then heating and curing the film. The cover layer 60 may also be produced by applying a liquid or paste-like thermosetting insulating resin to the upper surface 10a of the substrate 10 to cover the resistor 30, the wiring pattern 40, the electrode 40A, the electronic component 200, the metal wires 210 and 220, the electrode 50A, and the wiring pattern 50, and then heating and curing the resin.

[0060] Next, for example, a flexible solar cell is prepared as the solar cell 300 and laminated on the top surface of the cover layer 60. Then, using a well-known wiring formation method such as a subtractive method or a semi-additive method, a wiring pattern 70 is formed on the side surface of the cover layer 60, and predetermined terminals of the solar cell 300 are electrically connected to the wiring pattern 50.

[0061] Next, the substrate 10 is attached to the flexure element 510. Specifically, for example, any of the above materials that will become the adhesive layer 520 is applied to the lower surface 10b of the substrate 10 and / or the upper surface of the flexure element 510. Then, the lower surface 10b of the substrate 10 is made to face the upper surface of the flexure element 510, and the substrate 10 is placed on the flexure element 510 with the applied material sandwiched between them. Alternatively, a bonding sheet may be sandwiched between the flexure element 510 and the substrate 10.

[0062] Next, the substrate 10 is heated to a predetermined temperature while being pressed against the flexure element 510, and the applied material is cured to form the adhesive layer 520. This bonds the upper surface of the flexure element 510 and the lower surface 10b of the substrate 10 via the adhesive layer 520, completing the sensor module 5. The sensor module 5 can be used to measure, for example, load, pressure, torque, acceleration, etc.

[0063] In the manufacturing process of the sensor module 5, the solar cell 300 may be laminated on the upper surface of the cover layer 60 after the base material 10 is attached to the strain generating element 510.

[0064] In this way, in the sensor module 5, the base material 10 is provided with the resistor 30, the electronic component 200 electrically connected to the resistor 30, and the solar cell 300 which serves as a power source for supplying power to the electronic component 200. This makes it possible to realize a small sensor module that does not require external power supply.

[0065] In the sensor module 5, by making the resistor 30 thin, it is possible to reduce the power consumption and size of the sensor module 5 in particular.

[0066] That is, when a Cu-Ni or Ni-Cr foil is used as the material for resistor 30, the resistance value of resistor 30 is about 1 kΩ, but when a thin Cr mixed-phase film is used as the material for resistor 30, the resistance value of resistor 30 can be made 5 kΩ or more. Therefore, when a Cr mixed-phase film is used as the material for resistor 30, the current flowing through resistor 30 is reduced, making it possible to reduce power consumption. Furthermore, since the current supplied from solar cell 300 can be reduced due to the reduced power consumption, a smaller solar cell 300 can be used, and the entire sensor module 5 can be made smaller.

[0067] <Modification 1 of the First Embodiment> In Modification 1 of the first embodiment, an example of a sensor module in which a solar cell is mounted on the underside of a substrate is shown. Note that in Modification 1 of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0068] FIG. 3 is a cross-sectional view illustrating a sensor module according to a first modification of the first embodiment, showing a cross section corresponding to FIG.

[0069] 3, in the sensor module 5A, the solar cell 300 is mounted on the lower surface 10b side of the base material 10. Specifically, the solar cell 300 is disposed directly on the lower surface 10b of the base material 10, and is electrically connected to the wiring pattern 50 via the wiring pattern 70 provided on the side surface of the base material 10.

[0070] The direct arrangement referred to here means that no other components such as the cover layer 60 or the flexure element 510 are interposed between the solar cell 300 and the substrate 10, and the direct arrangement includes the case where an adhesive, adhesive sheet, or the like for fixing the solar cell 300 to the substrate 10 is interposed between the solar cell 300 and the substrate 10.

[0071] In addition, a strain generator 510 is fixed to the upper surface 10a of the base material 10 via an adhesive layer 520 so as to cover the resistor 30 and expose the wiring pattern 40, the electrodes 40A, the electronic component 200, the metal wires 210 and 220, the electrodes 50A, and the wiring pattern 50.

[0072] In the sensor module 5A, a cover layer may be provided on the upper surface 10a of the base material 10 so as to cover the wiring pattern 40, the electrodes 40A, the electronic components 200, the metal wires 210 and 220, the electrodes 50A, and the wiring pattern 50.

[0073] As such, in the sensor module, the position at which the solar cell is placed is not particularly limited, and it may be placed on the upper surface 10a side of the substrate 10 on which the resistor 30 is provided, or on the lower surface 10b side on which the resistor 30 is not provided.

[0074] <Modification 2 of the First Embodiment> In Modification 2 of the first embodiment, another example of a sensor module in which a solar cell is mounted on the underside of a substrate is shown. Note that in Modification 2 of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0075] FIG. 4 is a cross-sectional view illustrating a sensor module according to a second modification of the first embodiment, showing a cross section corresponding to FIG.

[0076] 4, in sensor module 5B, solar cell 300 is mounted on the lower surface 10b side of base material 10. Specifically, flexure body 510 is fixed to the lower surface 10b of base material 10 via adhesive layer 520, and solar cell 300 is disposed on the lower surface of flexure body 510. Solar cell 300 is electrically connected to wiring pattern 50 via wiring patterns 70 provided on each side of base material 10, adhesive layer 520, and flexure body 510.

[0077] In the sensor module 5B, a cover layer may be provided on the upper surface 10a of the base material 10 so as to cover the resistor 30, the wiring pattern 40, the electrodes 40A, the electronic component 200, the metal wires 210 and 220, the electrodes 50A, and the wiring pattern 50.

[0078] As described above, in the sensor module, the position at which the solar cell is placed is not particularly limited, and the solar cell may be placed on the upper surface 10a side of the substrate 10 on which the resistor 30 is provided, or on the lower surface 10b side on which the resistor 30 is not provided, via the strain-generating body 510 and the adhesive layer 520.

[0079] <Third Modification of the First Embodiment> In the third modification of the first embodiment, an example of a sensor module in which a protective layer is provided on a solar cell is shown. Note that in the third modification of the first embodiment, the description of the same components as those in the previously described embodiments may be omitted.

[0080] FIG. 5 is a cross-sectional view illustrating a sensor module according to a third modification of the first embodiment, showing a cross section corresponding to FIG.

[0081] 5, sensor module 5C differs from sensor module 5B (see FIG. 4) in that a protective layer 400 is provided on the light-receiving surface of solar cell 300.

[0082] In the sensor module 5C, a cover layer may be provided on the upper surface 10a of the base material 10 so as to cover the resistor 30, the wiring pattern 40, the electrodes 40A, the electronic component 200, the metal wires 210 and 220, the electrodes 50A, and the wiring pattern 50.

[0083] Protective layer 400 is formed by treating the light-receiving surface of solar cell 300 with an antifouling / antifogging treatment (silicone, fluorine-based treatment) or a photocatalytic material (TiO2, etc.), and is configured to transmit light of the wavelength that should be received by solar cell 300. By providing protective layer 400 on the light-receiving surface of solar cell 300, the power generation efficiency of solar cell 300 can be maintained.

[0084] The protective layer 400 can also be applied to the sensor modules 5, 5A, and 5B described above, and the sensor modules 5D, 5E, and 5F described below, and in this case too, the same effects as above can be achieved.

[0085] <Fourth Modification of the First Embodiment> In the fourth modification of the first embodiment, an example of a sensor module in which a solar cell is mounted on the upper surface of a substrate is shown. Note that in the fourth modification of the first embodiment, the description of the same components as those in the previously described embodiments may be omitted.

[0086] FIG. 6 is a cross-sectional view illustrating a sensor module according to a fourth modification of the first embodiment, showing a cross section corresponding to FIG.

[0087] 6, in the sensor module 5D, the solar cell 300 is mounted on the upper surface 10a side of the base material 10. Specifically, the solar cell 300 is directly disposed on the upper surface 10a of the base material 10 and is electrically connected to the wiring pattern 50. The meaning of "directly disposed" is as described above.

[0088] In the sensor module 5D, a cover layer may be provided on the upper surface 10a of the base material 10 so as to cover the resistor 30, the wiring pattern 40, the electrodes 40A, the electronic component 200, the metal wires 210 and 220, the electrodes 50A, and the wiring pattern 50.

[0089] As described above, in the sensor module, the position where the solar cell is disposed is not particularly limited, and the solar cell may be disposed directly on the upper surface 10a of the base material 10 on which the resistor 30 is provided.

[0090] Fifth Modification of the First Embodiment In the fifth modification of the first embodiment, an example of a sensor module having a plurality of resistors electrically connected to electronic components is shown. Note that in the fifth modification of the first embodiment, the description of the same components as those in the previously described embodiments may be omitted.

[0091] Fig. 7 is a partial plan view illustrating a sensor module according to Modification 5 of the first embodiment. Fig. 7 is an enlarged view of the area from resistor 30 to electronic component 200, similar to Fig. 1, and does not include cover layer 60, wiring pattern 70, and solar cell 300.

[0092] 2, the cross-sectional structure of the sensor module according to the fifth modification of the first embodiment is omitted, but the cover layer 60 is provided on the upper surface 10a of the base material 10 so as to cover the resistor 30, the wiring pattern 40, the electrodes 40A, the electronic component 200, the metal wires 210 and 220, the electrodes 50A, and the wiring pattern 50. The solar cell 300 is disposed on the upper surface of the cover layer 60, and is electrically connected to the wiring pattern 50 via the wiring pattern 70 provided on the side surface of the cover layer 60.

[0093] Referring to FIG. 7, the sensor module 5E differs from the sensor module 5 (see FIGS. 1 and 2) in that it has a plurality of sets of resistors 30, wiring patterns 40, and electrodes 40A.

[0094] Electronic component 200 is, for example, a semiconductor chip that amplifies and temperature-compensates electrical signals input from resistors 30 via wiring pattern 40 and electrodes 40A, and has the function of independently processing electrical signals input from multiple resistors 30. Passive components such as capacitors may be mounted together with the semiconductor chip.

[0095] Electrodes 200A of electronic component 200 are electrically connected to each pair of electrodes 40A via metal wires 210 such as gold wires or copper wires. Electrodes 200A and electrodes 40A can be connected by wire bonding, for example.

[0096] However, an electronic component may be individually mounted for each set of resistor 30, wiring pattern 40, and electrode 40A.

[0097] 7, the sensor module 5E has three sets of resistors 30, wiring patterns 40, and electrodes 40A, but is not limited to this, and the sensor module according to this embodiment may have two sets, or four or more sets, of resistors 30, wiring patterns 40, and electrodes 40A. The number of resistors 30 and the number of electrodes 40A do not have to be the same.

[0098] For example, as in a sensor module 5F shown in Fig. 8, four sets of resistors 30 may be connected by a wiring pattern 40 to form a Wheatstone bridge circuit. In this case, four connection points between the resistors 30 are connected to electrodes 40A via the wiring pattern 40. Note that the grid direction of each resistor 30 in Fig. 8 is an example and is not limited to this.

[0099] In this way, in the sensor modules 5E and 5F, multiple sets of resistors 30, wiring patterns 40, electrodes 40A, and electronic components 200 are provided on the upper surface 10a of a single substrate 10. This makes it possible to realize compact sensor modules 5E and 5F that are capable of detecting strain in multiple regions. Other effects are similar to those of the first embodiment.

[0100] As with the sensor modules 5E and 5F, the sensor modules 5A, 5B, 5C, and 5D described above can also have multiple sets of resistors 30, wiring patterns 40, electrodes 40A, and electronic components 200 provided on the upper surface 10a of a single substrate 10. In this case, too, a small sensor module capable of detecting strain in multiple regions can be realized.

[0101] The above describes in detail preferred embodiments, but 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.

[0102] For example, in the first embodiment and its modifications, a small battery (such as a lithium ion battery) may be used as the power source instead of the solar cell.

[0103] Furthermore, in the first embodiment and its modified examples, an example of laminating a flexible solar cell has been shown, but a solar cell may also be produced by sequentially laminating a first electrode layer, a power generation layer, a second electrode layer, etc. on a substrate, a cover layer, etc., by, for example, vapor deposition or sputtering. [Explanation of symbols]

[0104] 5, 5A, 5B, 5C, 5D, 5E, 5F sensor module, 10 substrate, 10a upper surface, 10b lower surface, 30 resistor, 40, 50 wiring pattern 40A, 50A, 200A, 200B electrode, 41 first layer, 42 second layer, 60 cover layer, 200 electronic component, 210, 220 metal wire, 300 solar cell, 400 protective layer, 510 strain element, 520 adhesive layer

Claims

1. a flexible resin substrate; a functional layer formed directly on one surface of the substrate from a metal, alloy, or metal compound; Cr, CrN, and Cr are directly applied to one surface of the functional layer. ２ a resistor formed from a film containing N and containing α-Cr as a main component; an electronic component mounted on one surface of the substrate and electrically connected to the resistor; a power supply mounted on one surface side or the other surface side of the substrate and electrically connected to the electronic component to supply power to the electronic component; the functional layer has a function of promoting crystal growth of the α-Cr and forming a film containing the α-Cr as a main component; The resistor has a thickness of 0.05 μm or more and 2 μm or less, The sensor module, wherein the thickness of the functional layer is 1 nm or more and 100 nm or less.

2. The sensor module according to claim 1 , wherein the power source is disposed directly on one surface of the substrate.

3. an insulating resin layer that covers the resistor and the electronic component on one surface of the base material; The sensor module according to claim 1 , wherein the power source is disposed on a surface of the insulating resin layer opposite to the base material.

4. The sensor module according to claim 1 , wherein the power source is disposed directly on the other surface of the substrate.

5. a strain generating element fixed to the other surface side of the base material via an adhesive layer; The sensor module according to claim 1 , wherein the power supply is disposed on a surface of the strain generating element opposite to the adhesive layer.

6. The sensor module according to claim 1 , wherein the power source is a solar cell.

7. The sensor module according to claim 6, wherein a protective layer is provided on the light-receiving surface of the solar cell.

8. The sensor module according to claim 1 , further comprising a plurality of resistors on the substrate, the resistors being electrically connected to the electronic components.

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