Stretchable device

Abstract

Provided is a stretchable device comprising: a stretchable substrate; stretchable wiring that is provided on the stretchable substrate and has a step portion on one end side in the longitudinal direction; non-stretchable wiring that is in contact with a first main surface and a first side surface of the step portion of the stretchable wiring; a non-stretchable substrate that is provided in contact with the non-stretchable wiring and the stretchable wiring; and an elastomer that surrounds a laminated portion including the stretchable wiring, the stretchable substrate, the non-stretchable wiring, and the non-stretchable substrate, wherein the stretchable wiring and the non-stretchable wiring have a connection part that is electrically connected.

Description

stretchable devices

[0001] The present disclosure relates to stretchable devices.

[0002] Stretchable devices including a stretchable wiring and a stretchable substrate, and a lead wiring and a non-stretchable reinforcing substrate have been known for some time. These stretchable devices can be used, for example, in living organisms or in equipment requiring stretchability.

[0003] In the stretchable device, when electrically connecting the stretchable wiring and the lead wire, the stretchable wiring and the lead wire are connected and a non-stretchable reinforcing substrate is provided on the lead wire. In this case, in order to improve the integration of the non-stretchable wiring with the non-stretchable reinforcing substrate, an elastomer may be interposed and disposed between the lead wire and the non-stretchable reinforcing substrate.

[0004] Patent No. 6405334

[0005] When connecting the above-mentioned stretchable wiring and the lead-out wiring that can correspond to the non-stretchable wiring, the lead-out wiring and the stretchable wiring may be partially overlapped and connected by thermocompression bonding to form a connection portion.

[0006] However, since the connection portion becomes thinner than the other portions due to crimping, there is a risk that the stretch resistance will be lower. Therefore, when stress is applied to the connection portion during stretching of the stretchable device, there is a risk that stress will be concentrated in the stretchable wire due to the low stretch resistance of the connection portion. Such stress concentration may cause uneven elongation between the connection portion and the other portions, which may cause breakage of the stretchable wire at the connection portion, making it impossible to perform a suitable electrical connection.

[0007] The present disclosure has been made in view of such problems. That is, an object of the present disclosure is to provide a stretchable device having excellent resistance to stretching at a connection portion formed between a stretchable wiring and a non-stretchable wiring due to deformation of the stretchable device.

[0008] In order to achieve the above object, one embodiment of the present disclosure provides a stretchable device comprising: a stretchable substrate; a stretchable wiring provided on the stretchable substrate and having a step portion on one end side in the longitudinal direction; a non-stretchable wiring in contact with a first main surface and a first side surface of the step portion of the stretchable wiring; a non-stretchable substrate provided in contact with the non-stretchable wiring and the stretchable wiring; and an elastomer surrounding a laminated portion including the stretchable wiring, the stretchable substrate, the non-stretchable wiring, and the non-stretchable substrate, wherein the stretchable wiring and the non-stretchable wiring have a connection portion where they are electrically connected.

[0009] According to a stretchable device according to one embodiment of the present disclosure, it is possible to provide a stretchable device in which the connection portion formed by the stretchable wiring and the non-stretchable wiring has excellent resistance to stretching caused by deformation of the stretchable device.

[0010] FIG. 1A is a cross-sectional view schematically showing a stretchable device according to a first embodiment of the present disclosure. FIG. 1B is a top view schematically showing a stretchable device according to the first embodiment of the present disclosure. FIG. 1C is a cross-sectional view schematically showing an IC-IC cross section of the stretchable device of FIG. 1B. FIG. 1D is a cross-sectional view schematically showing a modified example of a stretchable device according to the first embodiment of the present disclosure. FIG. 1E is a top view schematically showing a modified example of a stretchable device according to the first embodiment of the present disclosure. FIG. 2 is a cross-sectional view schematically showing a stretchable device according to a second embodiment of the present disclosure. FIG. 3A is a cross-sectional view schematically showing a stretchable device according to a third embodiment of the present disclosure. FIG. 3B is a cross-sectional view schematically showing a modified example of a stretchable device according to the third embodiment of the present disclosure. FIG. 3C is a top view schematically showing a stretchable device according to the third embodiment of the present disclosure.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each embodiment, differences from those previously described will be mainly described. In particular, similar effects resulting from similar configurations will not be mentioned in each embodiment. Among the components in the following embodiments, components not recited in independent claims will be described as optional components. Furthermore, the size and size ratios of components shown in the drawings are not necessarily strict. Furthermore, in each figure, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0012] In this specification, the "stretching direction" is preferably the longitudinal direction of the stretchable device, which is the extension direction of the stretchable substrate and stretchable wiring, from the viewpoint of more reliably preventing short circuits during use of the stretchable device, but it does not have to be stretched in one direction.

[0013] In this specification, the terms "thickness direction of the stretchable device" and "thickness direction of the substrate" may be used interchangeably. This direction corresponds to direction Y in the drawings. Furthermore, the terms "width direction of the laminated portion" and "width direction of the elastomer" may be used interchangeably. This direction corresponds to direction Z in the drawings.

[0014] As used herein, "cross-sectional view" or "cross-sectional shape" refers to the shape seen from a direction substantially perpendicular to the thickness direction of the stretchable device (for example, the X or Z direction in the drawing) (in simple terms, the shape seen when cut along a plane parallel to the thickness direction of the stretchable device). Furthermore, as used herein, "plan view" or "top view" refers to a sketch of an object seen from above or below along the thickness direction of the stretchable device.

[0015] Furthermore, in this specification, "above" an element includes not only the case of contacting the top surface of the element, but also the case of not contacting the top surface of the element. In other words, "above" an element does not only mean above the element, i.e., a position above the element via another object or a position above with a gap, but also a position directly above the element. Furthermore, "above" does not necessarily mean above in the vertical direction. "Above" merely indicates the relative positional relationship of an element.

[0016] [First Embodiment] The structure of a stretchable device 100 according to a first embodiment will be described with reference to FIGS. 1A to 1E. FIG. 1A is a cross-sectional view (in the IA-IA cross section of FIG. 1B described later) that schematically illustrates a stretchable device 100 according to the present disclosure. FIG. 1B is a top view of the stretchable device 100 of FIG. 1A. FIG. 1C is a cross-sectional view that schematically illustrates the stretchable device 100 according to the present disclosure. FIG. 1C is a cross-sectional view that schematically illustrates an IC-IC cross section of the stretchable device of FIG. 1B. FIG. 1D is a cross-sectional view (in the ID-ID cross section of FIG. 1E described later) that schematically illustrates a modified example of the stretchable device 100 according to the first embodiment of the present disclosure. FIG. 1E is a top view that schematically illustrates a modified example of the stretchable device 100 according to the first embodiment of the present disclosure. Note that cross-sectional views in this specification are views based on cross sections in the thickness direction of the stretchable substrate 10. Actual comparisons can also be confirmed by the above-described cross-sectional view at any position of a stretchable wiring 20 that stretches in a certain direction.

[0017] First, the basic components of the stretchable device 100 according to the first embodiment of the present disclosure will be described.

[0018] The stretchable device 100 according to the first embodiment of the present disclosure comprises a stretchable substrate 10, a stretchable wiring 20, a non-stretchable wiring 30, a non-stretchable substrate 40, and an elastomer 50. The stretchable wiring 20 is provided on at least the stretchable substrate 10. Specifically, the stretchable substrate 10 has a first main surface 11 and a second main surface 12 located on the opposite side of the first main surface 11, and the stretchable wiring 20 is provided on the first main surface 11 of the stretchable substrate 10.

[0019] The basic components of the stretchable device 100 will now be described in detail.

[0020] (Stretchable substrate 10) The stretchable substrate 10 is a sheet-like or film-like stretchable substrate, and is made of, for example, a stretchable resin material. Examples of the resin material for the stretchable substrate 10 include thermoplastic polyurethane (TPU), polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET).

[0021] (Stretchable Wiring 20) The stretchable wiring 20 contains conductive particles and a resin. Examples of the stretchable wiring 20 include a mixture of metal powder such as Ag (silver), Cu (copper), or Ni (nickel) as conductive particles and an elastomer resin such as a silicone resin. The average particle size of the conductive particles is not particularly limited, but is preferably 0.01 μm or more and 10 μm or less. Furthermore, the conductive particles are preferably spherical, but may also be flat powder or have a structure with protrusions to improve stretchability.

[0022] The thickness of the elastic wiring 20 is not particularly limited, but is preferably 100 μm or less, and more preferably 50 μm or less. The thickness of the elastic wiring 20 is preferably 0.01 μm or more. The line width of the elastic wiring 20 is not particularly limited, but is preferably 0.1 μm or more, and more preferably 10 mm or less.

[0023] Furthermore, for the sake of clarity, the drawings only show wiring that extends in a specific direction, but the stretchable wiring 20 may extend in any direction on the first main surface 11 of the stretchable substrate 10. Preferably, the stretchable wiring 20 may extend along the extension direction on the first main surface 11 of the stretchable substrate 10. Furthermore, in the thickness direction Y of the stretchable device 100, the stretchable wiring 20 does not necessarily have to be arranged in a straight line, and may be arranged in a curved line, for example. Furthermore, when viewed from the thickness direction Y, the stretchable wiring 20 does not necessarily have to extend in one direction. The number of stretchable wirings 20 is not particularly limited, and one or more wirings may be arranged.

[0024] (Non-stretchable Wiring 30) The non-stretchable wiring 30 is formed on the stretchable wiring 20 and the stretchable substrate 10 by patterning a predetermined conductive paste, and can correspond to a lead wiring. More specifically, after patterning the conductive paste (e.g., after printing), the solvent contained in the conductive paste is evaporated by heat treatment, thereby drying the conductive paste, thereby forming the non-stretchable wiring 30. The conductive paste used to form the non-stretchable wiring 30 is composed of a resin component as a binder and a conductive filler mixed therewith. This resin component preferably has a low glass transition temperature and a low elastic modulus. A thermoplastic binder is typically used. The conductive filler is not particularly limited, but silver (Ag) is typically used. Other materials such as copper (Cu) and carbon can also be used. The method for patterning the conductive paste is not particularly limited, but screen printing or the like is preferably used. The material of the non-elastic wire 30 may be the same as the material of the elastic wire 20, or may be another general thermosetting conductive paste.

[0025] The thickness of the non-elastic wire 30 is not particularly limited, but is preferably 10 μm or more, and more preferably about 15 μm, from the viewpoint of realizing good conductivity of the non-elastic wire 30. Furthermore, from the viewpoint of processing when patterning is performed by printing, the thickness of the non-elastic wire 30 is preferably 50 μm or less, and by doing so, it is possible to form a wire while ensuring process stability.

[0026] Furthermore, the non-stretchable wirings 30 do not necessarily have to be arranged in a straight line, and may be arranged in a curved line, for example, when viewed in the thickness direction Y or in a planar view of the stretchable device 100. Furthermore, the non-stretchable wirings 30 do not necessarily have to extend in one direction when viewed in the thickness direction Y or in a planar view, and the number of non-stretchable wirings 30 is not particularly limited, and one or more non-stretchable wirings 30 may be arranged.

[0027] (Non-stretchable substrate 40) The non-stretchable substrate 40 can be any of various substrates used depending on the application of the stretchable device 100. By way of example only, the non-stretchable substrate 40 may be a print substrate such as a flexible substrate. For example, the non-stretchable substrate 40 may be made of a material such as a glass epoxy substrate depending on the electrical and mechanical properties. The thickness of the non-stretchable substrate 40 is not particularly limited, but is preferably about 300 μm to about 2 mm.

[0028] (Elastomer 50) A thermoplastic elastomer can be used as the elastomer 50. Examples of the elastomer 50 include silicone-based, styrene-based, fluorine-based, urethane-based, and ethylene-based elastomers. The elastomer 50 may also be a thermosetting elastomer.

[0029] The thickness of the elastomer 50 is not particularly limited, but can vary depending on the thickness of the non-stretchable substrate 40. Therefore, it may be, for example, approximately 1 to 3 mm. Furthermore, it is preferable that the stretchability of the elastomer 50 be lower than that of the stretchable substrate 10 and the stretchable wiring 20, and that it be less stretchable. Here, the stretchability of the elastomer 50 can depend on the Young's modulus and the thickness and width (e.g., cross-sectional area) of the elastomer. For example, if the Young's modulus is high but the thickness and width of the elastomer are small, it may be possible for the elastomer 50 to have higher stretchability than the stretchable substrate 10 and the stretchable wiring 20. Conversely, if the Young's modulus is low but the thickness and width of the elastomer 50 are large, it may be less stretchable than the stretchable substrate 10 and the stretchable wiring 20, and may be less stretchable. Therefore, the stretchability of the elastomer 50 cannot be determined solely by the Young's modulus or the thickness and width, but these factors can be taken into consideration and the elastomer 50 can be appropriately adjusted so that its stretchability is lower than that of the stretchable substrate 10 and the stretchable wiring 20.

[0030] (Characteristic Parts of First Embodiment) Based on the details of the main components of the stretchable device 100 described above, the following will describe characteristic parts of the stretchable device 100 according to the first embodiment of the present disclosure.

[0031] First, as shown in FIG. 1A , in the first embodiment, in a cross-sectional view in the longitudinal direction of the stretchable substrate 10 (i.e., the IA-IA cross section in FIG. 1B ), a stretchable wire 20 is provided on the stretchable substrate 10, and has a step portion 25 on one end side in the longitudinal direction (i.e., the X direction). Specifically, one end side of the stretchable wire 20 has a step shape having a first main surface 21 and a first side surface 23, and extends on the first main surface 11 of the stretchable substrate 10. Furthermore, the stretchable wire 20 has a second main surface 22 that is continuous with the first side surface 23 and extends in the longitudinal direction of the stretchable substrate 10. The second main surface 22 faces the first main surface 11 of the stretchable substrate 10. Furthermore, the stretchable wire 20 also has a third main surface that is located on the opposite side of the second main surface 22 and is in contact with the first main surface 11 of the stretchable substrate 10. The second main surface 22 of the stretchable wiring 20 can be located above the first main surface 21 via the first side surface 23. Also, a non-stretchable wiring 30 is provided in contact with the first main surface 21 and the first side surface 23 of the step portion 25 of the stretchable wiring 20, and the non-stretchable wiring 30 and the stretchable wiring 20 are electrically connectable. The portion formed by connecting and overlapping a portion of the stretchable wiring 20 and the non-stretchable wiring 30 is referred to as a connection portion 60.

[0032] The non-stretchable wiring 30 is connected to the stretchable wiring 20 at a connection part 60, and extends in the opposite direction to the longitudinal direction of the stretchable wiring 20, with the connection part 60 as the reference. Furthermore, a part of the non-stretchable wiring 30 is in contact with the stretchable substrate 10, and the cross-sectional shape of the non-stretchable wiring 30 is rectangular when viewed from the thickness direction Y of the stretchable device 100. In other words, the thickness of the non-stretchable wiring 30 does not become thin when connected to the stretchable wiring 20, and therefore the occurrence of defects such as the non-stretchable wiring 30 becoming brittle or breaking from the stretchable wiring 20 can be reduced.

[0033] In this way, since the non-stretchable wiring 30 is electrically connected to the stretchable wiring 20, the stretchable device 100 (e.g., electronic components, etc.) can be easily electrically connected to an external device using the non-stretchable wiring 30.

[0034] 1A, the extension direction of the stretchable wiring 20 and the non-stretchable wiring 30 coincides with the longitudinal direction of the stretchable device 100, but this does not necessarily have to coincide. Furthermore, in the exemplary first embodiment shown in FIG. 1A, the stretchable wiring 20 and the non-stretchable wiring 30 are positioned above the first main surface 11 of the stretchable substrate 10 in the thickness direction Y, but this is not limited to this and the stretchable wiring 20 and the non-stretchable wiring 30 may be positioned below.

[0035] Furthermore, the stretchable device 100 of the present disclosure is characterized in that it comprises a non-stretchable substrate 40 provided on and in contact with the non-stretchable wiring 30 and the stretchable wiring 20, and an elastomer 50 surrounding a laminated portion 70 composed of (or including) the stretchable substrate 10, the stretchable wiring 20, and the non-stretchable wiring 30.

[0036] In such a configuration, the stretchable wiring 20 is in contact with both the non-stretchable substrate 40 and the elastomer 50, and further, the elastomer 50 can be in contact with the main surface of the stretchable substrate 10 opposite to the surface in contact with the stretchable wiring 20. Specifically, the second main surface 12 of the stretchable substrate 10 can be in contact with the elastomer 50.

[0037] Furthermore, in this structure, the second main surface 22 of the stretchable wiring 20 that faces the non-stretchable substrate 40 and the first main surface 31 of the non-stretchable wiring 30 that faces the non-stretchable substrate 40 are continuous, and this continuous portion is in contact with the non-stretchable substrate 40. In other words, the non-stretchable substrate 40 is provided in contact with the connection portion 60, the second main surface 22 of the stretchable wiring 20, and the first main surface 31 of the non-stretchable wiring 30.

[0038] In addition, the elastomer 50 is in contact with the first main surface 43 of the non-stretchable substrate 40, which is the main surface opposite to the surface that contacts the non-stretchable wiring 30 (corresponding to the surface that contacts the first main surface 31 of the non-stretchable wiring 30).

[0039] Here, the coverage area of ​​the elastomer 50 will be specifically described. In a cross-sectional view of the stretchable device 100 (specifically, the IA-IA cross section), the first side surface 51 of the elastomer 50 is located on at least the first side surface 61 of the connecting portion 60, and the second side surface 52 facing the first side surface 51 (located on the opposite side of the first side surface 51) is located so as to cover at least the first side surface 41 of the non-stretchable substrate 40 (see FIG. 1A ). In this case, the first side surface 51 of the elastomer 50 may be at least coaxial with the first side surface 61 of the connecting portion 60. Therefore, the elastomer 50 may integrally cover the laminated portion 70; in other words, a configuration in which the elastomer 50 surrounds at least the connecting portion 60 may be adopted. Note that the phrase "the first side surface 51 of the elastomer 50 is located on the first side surface 61 of the connecting portion 60" does not necessarily mean that the first side surface 51 of the elastomer 50 and the first side surface 61 of the connecting portion 60 are located on the same linear axis, but may also include a tolerance of approximately ±5%. In other words, the two surfaces are not necessarily aligned perfectly in a straight line, and some degree of misalignment is acceptable. However, it is necessary that the elastomer 50 cover the body portion that is continuous with the first side surface 61 of the connecting portion 60. Furthermore, the portion of the first side surface 51 of the elastomer 50 that is located below the stretchable substrate 10 (in the -Y direction, below the second main surface 12 of the stretchable substrate 10) and the portion that is located above the non-stretchable substrate 40 (in the +Y direction, above the first main surface 43 of the non-stretchable substrate 40) do not necessarily need to be flush with each other. If they are not flush with each other, the side surface distal to the first side surface 61 of the connecting portion 60 is referred to as the first side surface 51.

[0040] By adopting such a configuration, the stress applied to the connection part 60 when the stretchable device 100 is stretched can be dispersed to the elastomer 50. Furthermore, since the elastomer 50 surrounding the stacked part 70 has lower stretchability than the stretchable substrate 10 and the stretchable wiring 20, by covering the stacked part 70 (particularly the connection part 60), it is possible to prevent the connection part 60 from stretching excessively. As a result, the connection part 60 and other parts are stretched uniformly, and it is possible to obtain a stretchable device 100 that has excellent stretch resistance, such as stretch strength and durability.

[0041] The first side surface 51 of the elastomer 50 may cover the second side surface 42 of the non-stretchable substrate 40, as long as it covers at least the connecting portion 60. That is, the first side surface 41, the second side surface 42, and the first main surface 43 of the non-stretchable substrate 40 may be covered by and in contact with the elastomer 50 (see FIGS. 1D and 1E).

[0042] On the other hand, the second side surface 52 of the elastomer 50 is preferably located outside the first side surface 41 of the non-stretchable substrate 40, and cannot be located flush with or inside the first side surface 41 of the non-stretchable substrate 40. That is, the first side surface 41 of the non-stretchable substrate 40 and the connection portion 60 are preferably located inside the second side surface 52 of the elastomer 50. Note that, in a cross-sectional view of the stretchable device 100 (specifically, the IA-IA cross section), the term "inside" refers to a side that is relatively closer to the stacked portion 70, with the position of the stacked portion 70 as the reference. On the other hand, the term "outside" refers to a side that is relatively farther from the stacked portion 70, with the position of the stacked portion 70 as the reference. Furthermore, the second side surface 52 of the elastomer 50 may be located distal to the first side surface 41 as long as it covers the first side surface 41 of the non-stretchable substrate 40, but does not cover the entire surfaces of the stretchable substrate 10 and the stretchable wiring 20. In other words, the second side 52 of the elastomer 50 may cover a portion of the stretchable wiring 20 and the stretchable substrate 10 in an exposable manner, and the elastomer 50 may cover the entire stretchable device 100 as long as it covers the stretchable wiring 20 in an exposable manner.

[0043] By covering the elastomer 50 within the range described above, it is possible to increase the adhesion between the components of the laminated portion 70, and this can contribute to suppressing the occurrence of peeling and detachment at the interface between the components (for example, the stretchable substrate 10 and the stretchable wiring 20, etc.) It can also contribute to protecting the stretchable substrate 10, the stretchable wiring 20, the non-stretchable wiring 30, and the non-stretchable substrate 40 from thermal or mechanical shock.

[0044] Next, a cross-sectional view ( FIG. 1C ) schematically illustrating the IC-IC cross section of the stretchable device in FIG. 1B will be described. As shown in FIG. 1C , in the IC-IC cross section, stretchable wiring 20, non-stretchable wiring 30, and non-stretchable substrate 40 are alternately stacked on a stretchable substrate 10, and this stacked portion 70 is integrally covered with an elastomer 50. Therefore, in the width direction Z and thickness direction Y of the elastomer 50 in the IC-IC cross section, the thickness and width of the elastomer 50 can be greater than the thickness and width of the stacked portion 70 composed of the stretchable substrate 10, stretchable wiring 20, non-stretchable wiring 30, and non-stretchable substrate 40. In this case, the shape of the elastomer 50 in cross-sectional view and top view may be rectangular (see FIGS. 1B and 1C ).

[0045] From another perspective, as shown in FIG. 1C , in the laminated portion 70, the elastomer 50 is disposed so as to surround the stretchable substrate 10. That is, in a cross-sectional view of the laminated portion 70 in the width direction Z, the side surface of the stretchable substrate 10 is in contact with the elastomer 50. Furthermore, a structure can be formed in which the elastomer 50 covers the periphery of the connection portion 60 composed of the stretchable wiring 20 and the non-stretchable wiring 30. This increases the adhesion between the stretchable wiring 20 and the non-stretchable wiring 30, and the connection portion 60 can be stably held. As a result, the occurrence of defects such as rupture of the stretchable wiring 20 and the non-stretchable wiring 30 during stretching can be suppressed. Accordingly, the reliability of the stretchable device 100 can be improved.

[0046] Due to the above-described structure, the elastomer 50 is located on the outer surface of the stretchable device 100. That is, it may cover the outer surfaces of the stretchable wiring 20, the stretchable substrate 10, and the non-stretchable substrate 40. In other words, in a top view of the stretchable device 100 as shown in Fig. 1B, in the area where the elastomer 50 is present, only the elastomer 50 is visible, and the stretchable substrate 10, the non-stretchable substrate 40, etc. are not visible.

[0047] With this structure, when the stretchable device 100 is stretched along the extension direction of the main surface (for example, the first main surface 11 of the stretchable substrate 10), it is possible to alleviate stress concentration on the stretchable wiring 20 of the connection part 60, and to suppress the occurrence of physical damage such as breakage of the stretchable wiring 20. This can reduce errors in the signal transmitted by the stretchable wiring 20. In this respect, a high-precision stretchable device 100 can be provided.

[0048] (Method for Producing a Stretchable Device) An exemplary method for producing a stretchable device according to an embodiment of the present disclosure will now be described.

[0049] First, prepare the stretchable substrate 10. After preparing the stretchable substrate 10, the stretchable wiring 20 is formed on the main surface (for example, the first main surface 11) of the stretchable substrate 10 along the extension direction of the main surface of the stretchable substrate 10.

[0050] The stretchable wiring 20 may be formed by printing a conductive paste (for example, a conductive paste containing a mixture of silver and resin) onto the stretchable substrate 10 using screen printing, inkjet printing, or the like. This allows a desired circuit pattern to be obtained.

[0051] After forming a circuit pattern of the stretchable wiring 20 on the stretchable substrate 10, the stretchable wiring 20 may be formed on the stretchable substrate 10 by drying and curing. Note that it is also possible to mount components such as sensors as necessary.

[0052] Next, a non-stretchable substrate 40 is prepared, and the non-stretchable wiring 30 is formed along the extension direction of the main surface (for example, the surface opposite the first main surface 43) of the non-stretchable substrate 40. The non-stretchable wiring 30 may be formed by printing a conductive paste by a method such as screen printing, similar to the case of the previously described stretchable wiring 20. Note that the order of the step of forming the stretchable wiring 20 on the stretchable substrate 10 and the step of arranging the non-stretchable wiring 30 on the non-stretchable substrate 40 may be any order, or they may be produced in parallel.

[0053] Next, the stretchable wiring 20 arranged on the stretchable substrate 10 and the non-stretchable wiring 30 arranged on the non-stretchable substrate 40 are aligned and superimposed so as to partially overlap in the thickness direction Y, and then bonded to each other. At this time, the stretchable wiring 20 and the non-stretchable wiring 30 may be connected by applying a predetermined temperature or the like, to form a connection portion 60.

[0054] Furthermore, the structure obtained above (specifically, the stretchable substrate 10, the stretchable wiring 20, the non-stretchable wiring 30, and the non-stretchable substrate 40) may be placed in a predetermined mold, and then the heated and melted elastomer 50 may be poured into the mold under pressure using injection molding to form the elastomer 50. Thereafter, the elastomer 50 may be cooled and removed from the mold, thereby obtaining the stretchable device 100.

[0055] The obtained stretchable device 100 has a shape in which the elastomer 50 surrounds a laminated portion 70 configured from (or including) the stretchable wiring 20, the stretchable substrate 10, the non-stretchable wiring 30, and the non-stretchable substrate 40. Specifically, the first side surface 51 of the elastomer 50 is on the first side surface 61 of the connection portion 60, and the second side surface 52 covers at least the first side surface 41 of the non-stretchable substrate 40.

[0056] That is, since the connection portion 60 of the stretchable wiring 20, which has been thinned by the above-mentioned pressing, is surrounded by the elastomer 50, it is possible to obtain a stretchable device 100 that has excellent stretch resistance, specifically the stretch resistance of the connection portion 60, compared to conventional devices in which the connection portion is not surrounded by the elastomer.

[0057] This makes it possible to alleviate stress concentration on the stretchable wiring 20 at the connection part 60 when the stretchable device 100 is stretched along the extension direction of the main surface, and allows for uniform stretching at the connection part 60 and other parts. As a result, it becomes possible to suppress the occurrence of physical damage such as breakage of the stretchable wiring 20.

[0058] Second Embodiment Hereinafter, the configuration of a stretchable device 200 according to a second embodiment will be described with reference to Fig. 2. The second embodiment differs from the first embodiment in that, in the XY cross section, the end face of the stretchable substrate 10 proximal to the laminated portion 70 in the longitudinal direction is thinner than the end face distal to it. Specifically, the stretchable substrate 10 has a first side surface 14 and a second side surface 15 located opposite the first side surface 14, and the first side surface 14 can be thinner than the second side surface 15. Fig. 2 is a cross-sectional view schematically showing a stretchable device 200 according to a second embodiment of the present disclosure.

[0059] Furthermore, when producing the stretchable device 200 according to the second embodiment, the production method differs from that of the first embodiment in that it includes a step of thermocompression bonding the first side surface 14 and the stretchable wiring 20 arranged in contact therewith by applying pressure or the like to the stretchable substrate 10. By producing it by this method, it is possible to produce the stretchable device 200 according to the second embodiment in which the end face on the proximal side with respect to the laminated portion 70 in the longitudinal direction of the stretchable substrate 10 is thinner than the end face on the distal side.

[0060] The stretchable device 200 according to the second embodiment of the present disclosure comprises a stretchable substrate 10 , a stretchable wiring 20 , a non-stretchable wiring 30 , a non-stretchable substrate 40 , and an elastomer 50 .

[0061] 2, the stretchable substrate 10 has a first side surface 14 and a second side surface 15 located on the opposite side of the first side surface 14, and the first side surface 14 is thinner than the second side surface 15. The coverage area of ​​the elastomer 50 may be the same as in the first embodiment.

[0062] As in the second embodiment, by thinning the first side surface 14 side of the stretchable substrate 10, the contact area of ​​the stretchable substrate 10 with the elastomer 50 increases, and adhesion can be improved. Therefore, this can contribute to obtaining a stretchable device 200 with even higher stretching strength and durability than the first embodiment. Furthermore, by performing the crimping process, the connection portion 60 (including the laminated portion 70) can be deformed, and the overall thickness can change. In other words, it is possible to reduce the overall thickness of the elastomer 50, thereby making it possible to reduce the overall height of the stretchable device 200.

[0063] From another perspective, when the thickness of the elastomer 50 in the first and second embodiments is constant, if the first side surface 14 of the stretchable substrate 10 is made thinner as in the second embodiment, the overall thickness including the laminated portion 70 will be thinner. Therefore, as shown in Figure 2, the area in which the elastomer 50 is present in cross section will be larger than in the first embodiment. In other words, the effect of the elastomer 50 (e.g., suppression of excessive stretching) can be further obtained by this increased area compared to the first embodiment, and therefore, more uniform stretching may be possible than in the first embodiment.

[0064] [Third Embodiment] Hereinafter, the configuration of a stretchable device 300 according to a third embodiment will be described with reference to FIGS. 3A to 3C. The third embodiment differs from the first embodiment in that the stretchable substrate 10 covers two mutually opposing main surfaces of the stretchable wiring 20. Specifically, the stretchable substrate 10 further covers the second main surface 22 and the second side surface 24 opposing the first side surface 23 of the stretchable wiring 20. FIG. 3A is a cross-sectional view (taken along the IIIA-IIIA cross section in FIG. 3C described later) that schematically illustrates a stretchable device 300 according to a third embodiment of the present disclosure. FIG. 3B is a cross-sectional view (taken along the IIIA-IIIA cross section in FIG. 3C described later) that schematically illustrates a modified example of the stretchable device 300 according to the third embodiment of the present disclosure. FIG. 3C is a top view that schematically illustrates the stretchable device 300 according to the third embodiment of the present disclosure.

[0065] Furthermore, when producing the stretchable device 300 of the third embodiment, the method differs from the production method of the first embodiment in that it includes a step of printing the stretchable wiring 20 on the stretchable substrate 10 and then overlaying another stretchable substrate 10. By producing it using this method, it is possible to produce the stretchable device 300 according to the third embodiment in which the stretchable substrate 10 covers two mutually opposing main surfaces of the stretchable wiring 20 (specifically, the second main surface 22 and the third main surface of the stretchable wiring 20).

[0066] A stretchable device 300 according to the third embodiment of the present disclosure comprises a stretchable substrate 10, a stretchable wiring 20, a non-stretchable wiring 30, a non-stretchable substrate 40, and an elastomer 50, and the stretchable substrate 10 covers two mutually opposing main surfaces of the stretchable wiring 20 (see FIGS. 3A and 3B ).

[0067] Specifically, the stretchable substrate 10 further covers the second main surface 22 and second side surface 24 of the stretchable wiring 20 that face the first main surface 11 of the stretchable substrate 10. In this case, for example, only a portion of the second main surface 22 of the stretchable wiring 20 may be covered, or the entire second main surface 22 may be covered to the extent that it does not come into contact with the first side surface 41 of the non-stretchable substrate 40. With such a configuration, the exposed area of ​​the stretchable wiring 20 can be reduced, and therefore the stretchable wiring 20 can be protected. Therefore, because the contact area between the stretchable substrate 10 and the stretchable wiring 20 increases, it may be possible to further alleviate stress concentration on the stretchable wiring 20 during extension compared to the first and second embodiments.

[0068] As described above, the stretchable substrate 10 may cover only a portion of the stretchable wiring 20, and therefore the elastomer 50 may be positioned such that, for example, the second side surface 52 covers the first side surface 41 of the non-stretchable substrate 40, the second main surface 22 of the stretchable wiring 20, and the second main surface 12 of the stretchable substrate 10. The coverage of the first side surface 51 of the elastomer 50 is the same as in the first embodiment.

[0069] Furthermore, the elastomer 50 may cover the two main surfaces of the stretchable substrate 10 that face the surface that contacts the stretchable wiring 20. Specifically, the elastomer 50 may cover the area where both the second main surface 12 and the third main surface 13 of the stretchable substrate 10 are present (see FIGS. 3A and 3B ). In this case, the second side surface 52 of the elastomer 50 cannot be located in the portion of the stretchable wiring 20 that is not covered by the stretchable substrate 10. In other words, because the stretchable wiring 20 is covered by the stretchable substrate 10 and the elastomer 50, the stretchable wiring 20 cannot be seen in the top view of the stretchable device 300 in FIG. 3C . Furthermore, for example, the more distal the position of the second side surface 52 of the elastomer 50 is from the first side surface 41 of the non-stretchable substrate 40, the larger the contact area between the stretchable substrate 10 and the elastomer 50. This improves the adhesion of the entire stretchable device 300, improving connection reliability and also contributing to further improving protection from mechanical and thermal shocks.

[0070] By having the elastomer 50 surround both the stretchable substrate 10 and the stretchable wiring 20 within the above range, the stress associated with the stretchable device 300 when it is stretched can be dispersed to the elastomer 50. Therefore, it is possible to better maintain the stretch resistance of the stretchable device 300, for example, the stretch resistance of the stretchable substrate 10 and the stretchable wiring 20. Note that, as shown in Fig. 3B, the first side surface 14 of the stretchable substrate 10 may be thinner than the second side surface 15, similar to the second embodiment.

[0071] Although the embodiments of the present disclosure have been described above, they are merely exemplary examples. The present disclosure is not limited thereto, and those skilled in the art will easily understand that various embodiments are possible within the scope of the present disclosure. Furthermore, partial substitution or combination of the configurations shown in the different embodiments and modified examples is possible. One embodiment of the present disclosure as described above includes the following preferred aspects. First aspect: A stretchable device comprising: a stretchable substrate; a stretchable wiring provided on the stretchable substrate and having a step portion on one end side in the longitudinal direction; a non-stretchable wiring in contact with a first main surface and a first side surface of the step portion of the stretchable wiring; a non-stretchable substrate provided in contact with the non-stretchable wiring and the stretchable wiring; and an elastomer surrounding a laminated portion including the stretchable wiring, the stretchable substrate, the non-stretchable wiring, and the non-stretchable substrate, wherein the stretchable wiring and the non-stretchable wiring have a connection portion electrically connected. Second Aspect: The stretchable device of the first aspect, wherein, in a cross-sectional view, a first side surface of the elastomer is at least on a first side surface of the connecting portion, and a second side surface opposite to the first side surface of the elastomer covers at least the first side surface of the non-stretchable substrate. Third Aspect: The stretchable device of the first or second aspect, wherein the elastomer integrally covers the laminated portion. Fourth Aspect: The stretchable device of the second aspect, wherein the second side surface of the elastomer covers the stretchable wiring and a portion of the stretchable substrate in an exposable manner. Fifth Aspect: The stretchable device of any of the first to fourth aspects, wherein the thickness and width of the elastomer are greater than the thickness and width of the laminated portion. Sixth Aspect: The stretchable device of any of the first to fifth aspects, wherein the elastomer is located on the outer surface of the stretchable device. Seventh aspect: The stretchable device according to any one of the first to sixth aspects, wherein the elastomer is disposed so as to surround the stretchable substrate in the laminated portion. Eighth aspect: The stretchable device according to any one of the first to seventh aspects, wherein the elastomer is in contact with a main surface of the stretchable substrate opposite to a surface in contact with the stretchable wiring.Ninth aspect: A stretchable device according to any one of the first to eighth aspects, wherein a side surface of the stretchable substrate contacts the elastomer in a cross section in the width direction of the laminated portion. Tenth aspect: A stretchable device according to any one of the first to ninth aspects, wherein the elastomer contacts a main surface of the non-stretchable substrate opposite to a surface that contacts the non-stretchable wiring. Eleventh aspect: A stretchable device according to any one of the first to tenth aspects, wherein the stretchable wiring contacts both the non-stretchable substrate and the elastomer. Twelfth aspect: A stretchable device according to the second aspect, wherein a second side surface of the elastomer is located outside the first side surface of the non-stretchable substrate. 13th Aspect: A stretchable device in any one of the first to 12th aspects, wherein a second main surface of the stretchable wiring that faces the non-stretchable substrate and a first main surface of the non-stretchable wiring that faces the non-stretchable substrate are continuous, and the continuous portion is in contact with the non-stretchable substrate. 14th Aspect: A stretchable device in any one of the first to 13th aspects, wherein the non-stretchable substrate is in contact with the stretchable wiring and the non-stretchable wiring. 15th Aspect: A stretchable device in any one of the first to 14th aspects, wherein the elastomer surrounding the laminated portion has lower stretchability than the stretchable substrate and the stretchable wiring. 16th Aspect: A stretchable device in any one of the first to 15th aspects, wherein the cross-sectional shape of the non-stretchable wiring in the thickness direction is rectangular. 17th Aspect: The stretchable device according to any one of the first to sixteenth aspects, wherein, in a cross-sectional view, an end face of the stretchable substrate on a proximal side relative to the laminated portion in the longitudinal direction is thinner than an end face on a distal side. 18th Aspect: The stretchable device according to any one of the first to seventeenth aspects, wherein the stretchable substrate further covers a second main surface of the stretchable wiring that faces a first main surface of the stretchable substrate. 19th Aspect: The stretchable device according to the eighteenth aspect, wherein the elastomer covers two main surfaces of the stretchable substrate that face the surface that faces the stretchable wiring.

[0072] 100, 200, 300: Stretchable device 10: Stretchable substrate 11: First main surface of stretchable substrate 12: Second main surface of stretchable substrate 13: Third main surface of stretchable substrate 14: First side surface of stretchable substrate 15: Second side surface of stretchable substrate 20: Stretchable wiring 21: First main surface of stretchable wiring 22: Second main surface of stretchable wiring 23: First side surface of stretchable wiring 24: Second side surface of stretchable wiring 25: Step portion of stretchable wiring 30: Non-stretchable wiring (corresponding to lead-out wiring) 31: First main surface of non-stretchable wiring 40: Non-stretchable substrate 41: First side surface of non-stretchable substrate 42: Second side surface of non-stretchable substrate 43: First main surface of non-stretchable substrate 50: Elastomer 51: First side surface of elastomer 52: Second side surface of elastomer 60: Connection portion 61: First side surface of connecting portion 70: Laminated portion

Claims

1. A stretchable device comprising: a stretchable substrate; a stretchable wiring provided on the stretchable substrate and having a stepped portion on one end side in the longitudinal direction; a non-stretchable wiring in contact with a first main surface and a first side surface of the stepped portion of the stretchable wiring; a non-stretchable substrate provided in contact with the non-stretchable wiring and the stretchable wiring; and an elastomer surrounding a layered portion including the stretchable wiring, the stretchable substrate, the non-stretchable wiring, and the non-stretchable substrate, wherein the stretchable wiring and the non-stretchable wiring have a connection portion where they are electrically connected.

2. The stretchable device of claim 1, wherein, in a cross-sectional view, a first side of the elastomer is on at least a first side of the connecting portion, and a second side of the elastomer opposite the first side covers at least the first side of the non-stretchable substrate.

3. The stretchable device according to claim 1 or 2, wherein the elastomer integrally covers the laminated portion.

4. The stretchable device according to claim 2, wherein the second side of the elastomer covers the stretchable wiring and a portion of the stretchable substrate in an exposable manner.

5. The stretchable device according to any one of claims 1 to 4, wherein the thickness and width of the elastomer are greater than the thickness and width of the laminated portion.

6. The stretchable device of any one of claims 1 to 5, wherein the elastomer is located on an outer surface of the stretchable device.

7. The stretchable device according to any one of claims 1 to 6, wherein in the laminated portion, the elastomer is disposed so as to surround the stretchable substrate.

8. The stretchable device according to any one of claims 1 to 7, wherein the main surface of the stretchable substrate opposite to the surface in contact with the stretchable wiring is in contact with the elastomer.

9. The stretchable device according to any one of claims 1 to 8, wherein, in a cross-sectional view in the width direction of the laminated portion, a side surface of the stretchable substrate contacts the elastomer.

10. The stretchable device according to any one of claims 1 to 9, wherein the elastomer is in contact with a main surface of the non-stretchable substrate opposite to a surface in contact with the non-stretchable wiring.

11. The stretchable device according to any one of claims 1 to 10, wherein the stretchable wiring is in contact with both the non-stretchable substrate and the elastomer.

12. The stretchable device of claim 2, wherein the second side of the elastomer is located outside the first side of the non-stretchable substrate.

13. The stretchable device according to any one of claims 1 to 12, wherein a second main surface of the stretchable wiring that faces the non-stretchable substrate and a first main surface of the non-stretchable wiring that faces the non-stretchable substrate are continuous, and the continuous portion is in contact with the non-stretchable substrate.

14. The stretchable device according to any one of claims 1 to 13, wherein the non-stretchable substrate is in contact with the stretchable wiring and the non-stretchable wiring.

15. The stretchable device according to any one of claims 1 to 14, wherein the elastomer surrounding the laminated portion has lower stretchability than the stretchable substrate and the stretchable wiring.

16. The stretchable device according to any one of claims 1 to 15, wherein the cross-sectional shape of the non-stretchable wiring in the thickness direction is rectangular.

17. The stretchable device according to any one of claims 1 to 16, wherein, in a cross-sectional view, the end face of the stretchable substrate on the proximal side relative to the laminated portion in the longitudinal direction is thinner than the end face on the distal side.

18. The stretchable device according to any one of claims 1 to 17, wherein the stretchable substrate further covers a second main surface of the stretchable wiring that faces the first main surface of the stretchable substrate.

19. The stretchable device of claim 18, wherein the elastomer covers two major surfaces of the stretchable substrate opposite a surface in contact with the stretchable wiring.

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