Stretchable device

Abstract

Provided in an embodiment of the present invention is a stretchable device comprising: a stretchable base material; first stretchable wiring that is disposed on the stretchable base material and that has a first electrode part; second stretchable wiring that is disposed on the first stretchable wiring and that has a second electrode part; and an interlayer sheet that is disposed between the first stretchable wiring and the second stretchable wiring, wherein the interlayer sheet has a sheet part and at least one first via part that is provided to the sheet part, and the first via part has, at a portion thereof, a connection region that connects the first electrode part and the second electrode part.

Description

stretchable devices

[0001] The present invention relates to a stretchable device.

[0002] Conventionally, a stretchable device has been known that includes a stretchable substrate, a first stretchable wiring disposed on the stretchable substrate, and a second stretchable wiring disposed on the first stretchable wiring and connected via a via.

[0003] Japanese Patent Application Laid-Open No. 2021-77579

[0004] The inventors of the present application have found that the following points need to be improved in conventional stretchable devices. Specifically, if the positional accuracy between a via used to interconnect two stretchable wires and the electrode portion of the upper second stretchable wire is not constant, it may be difficult to improve the connection reliability between the electrode portion of the lower first stretchable wire and the electrode portion of the upper second stretchable wire. In particular, when the entire device stretches, such as in a stretchable device, misalignment is likely to occur, and therefore high connection reliability is required.

[0005] Therefore, an object of the present invention is to provide a stretchable device that can improve the connection reliability between the electrode portions of two mutually adjacent stretchable wirings.

[0006] In order to achieve the above object, one embodiment of the present invention provides a stretchable device comprising: a stretchable substrate; a first stretchable wiring disposed on the stretchable substrate and having a first electrode portion; a second stretchable wiring disposed on the first stretchable wiring and having a second electrode portion; and an interlayer sheet disposed between the first stretchable wiring and the second stretchable wiring, wherein the interlayer sheet includes a sheet portion and at least one first via portion provided in the sheet portion, and the first via portion partially has a connection region that connects the first electrode portion and the second electrode portion.

[0007] According to a stretchable device according to one embodiment of the present invention, it is possible to improve the connection reliability between the electrode portions of two mutually adjacent stretchable wirings.

[0008] FIG. 1 is a plan view schematically showing a stretchable device according to a first embodiment of the present invention. FIG. 2A is a plan view schematically showing a stretchable device according to a second embodiment of the present invention. FIG. 2B is a plan view schematically showing a modified example of a stretchable device according to the second embodiment of the present invention. FIG. 3A is a plan view schematically showing step 1 of a method for producing a stretchable device according to the second embodiment of the present invention. FIG. 3B is a plan view schematically showing step 2 of a method for producing a stretchable device according to the second embodiment of the present invention. FIG. 3C is a plan view schematically showing step 3 of a method for producing a stretchable device according to the second embodiment of the present invention. FIG. 3D is a plan view schematically showing step 4 of a method for producing a stretchable device according to the second embodiment of the present invention. FIG. 3E is a plan view schematically showing step 5 of a method for producing a stretchable device according to the second embodiment of the present invention. FIG. 4A is a plan view schematically showing step 1 of a method for producing a modified example of a stretchable device according to the second embodiment of the present invention. FIG. 4B is a plan view schematically showing step 2 of a method for producing a modified example of a stretchable device according to the second embodiment of the present invention. 4C is a plan view schematically showing step 3 of the method for producing a modified stretchable device according to the second embodiment of the present invention. FIG. 4D is a plan view schematically showing step 4 of the method for producing a modified stretchable device according to the second embodiment of the present invention. FIG. 4E is a plan view schematically showing step 5 of the method for producing a modified stretchable device according to the second embodiment of the present invention. FIG. 5 is a plan view schematically showing a stretchable device according to a third embodiment of the present invention. FIG. 6A is a plan view schematically showing a first modified stretchable device according to the third embodiment of the present invention. FIG. 6B is a cross-sectional view schematically showing the structure between A-A in FIG. 6A. FIG. 7A is a plan view schematically showing a second modified stretchable device according to the third embodiment of the present invention. FIG. 7B is a cross-sectional view schematically showing the structure between B-B in FIG. 7A. FIG. 8A is a plan view schematically showing a third modified stretchable device according to the third embodiment of the present invention. FIG. 8B is a cross-sectional view schematically showing the structure between A-A in FIG. 8A. FIG. 8C is a cross-sectional view schematically showing the structure between B-B in FIG. 8A. Fig. 9A is a plan view schematically showing a fourth modification of the stretchable device according to the third embodiment of the present invention, and Fig. 9B is a cross-sectional view schematically showing the structure between A-A in Fig. 9A.9C is a cross-sectional view schematically showing the structure between B-B in FIG. 9A . FIG. 10A is a plan view schematically showing a fifth modified example of a stretchable device according to the third embodiment of the present invention. FIG. 10B is a cross-sectional view schematically showing the structure between A-A in FIG. 10A . FIG. 10C is a cross-sectional view schematically showing the structure between B-B in FIG. 10A . FIG. 11A is a plan view schematically showing a sixth modified example of a stretchable device according to the third embodiment of the present invention. FIG. 11B is a cross-sectional view schematically showing the structure between A-A in FIG. 11A . FIG. 12A is a plan view schematically showing a seventh modified example of a stretchable device according to the third embodiment of the present invention. FIG. 12B is a cross-sectional view schematically showing the structure between A-A in FIG. 12A . FIG. 13A is a plan view schematically showing step 1 of a method for producing a stretchable device according to the third embodiment of the present invention. FIG. 13B is a plan view schematically showing step 2 of a method for producing a stretchable device according to the third embodiment of the present invention. Fig. 13C is a plan view schematically showing step 3 of the method for producing a stretchable device according to the third embodiment of the present invention, Fig. 13D is a plan view schematically showing step 4 of the method for producing a stretchable device according to the third embodiment of the present invention, and Fig. 13E is an enlarged plan view schematically showing step 5 of the method for producing a stretchable device according to the third embodiment of the present invention.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, differences from previous embodiments 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 drawing, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0010] [First embodiment] Hereinafter, the configuration of a stretchable device 100 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a plan view schematically showing a stretchable device according to an embodiment of the present invention.

[0011] The stretchable device 100 according to the first embodiment of the present invention comprises a stretchable substrate, a first stretchable wiring 20 disposed on the stretchable substrate, a second stretchable wiring 30 disposed on the first stretchable wiring 20, and an interlayer sheet 40 disposed between the first stretchable wiring 20 and the second stretchable wiring 30.

[0012] In this specification, "above" includes a state of being above an element at a distance, i.e., being above an element via another object, a state of being above an element with a gap, and a state of being directly above an element.

[0013] Therefore, in this specification, the "first stretchable wiring 20 arranged on the stretchable substrate" includes a first stretchable wiring 20 in contact with the main surface of the stretchable substrate, and a first stretchable wiring 20 in a state where it is separated from the main surface via another member (for example, a resin layer described below) without directly contacting the main surface of the stretchable substrate.

[0014] The resin layer may be made of at least one resin material selected from the group consisting of polyimide resins, epoxy resins, urethane resins, and acrylic resins, or may be made of an inorganic material such as alumina or silicon dioxide.

[0015] The stretchable substrate is a sheet-like or film-like stretchable substrate made of, for example, a stretchable resin material, such as thermoplastic polyurethane (TPU), styrene-based elastomer, polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), etc.

[0016] The thickness of the stretchable substrate is not particularly limited, but is preferably 100 μm or less, more preferably 50 μm or less, from the viewpoint of not inhibiting the stretching of the surface of the living body when attached to the living body. Furthermore, the thickness of the stretchable substrate is preferably 20 μm or more from the viewpoint of ensuring a predetermined strength.

[0017] The first stretchable wire 20 and the second stretchable wire 30 each contain conductive particles and a resin. Examples of the stretchable wires include a mixture of conductive particles such as metal powder of Ag, Cu, or Ni, 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.

[0018] The thickness of each elastic wire is not particularly limited, but is preferably 100 μm or less, and more preferably 50 μm or less. The thickness of each elastic wire is preferably 0.01 μm or more. The line width of each elastic wire is not particularly limited, but is preferably 0.1 μm or more, and more preferably 10 mm or less. The shape of each elastic wire is also not particularly limited.

[0019] Furthermore, the first stretchable wire 20 has a first electrode portion 21 and a first extension portion 22 extending in a predetermined direction from the first electrode portion 21. The second stretchable wire 30 has a second electrode portion 31 and a second extension portion 32 extending in a predetermined direction from the second electrode portion 31. In a plan view, the first electrode portion 21 and the second electrode portion 31 overlap each other. Furthermore, the first extension portion 22 and the second extension portion 32 may extend in opposite directions to each other. Without being limited thereto, the first extension portion 22 and the second extension portion 32 may extend in the same direction.

[0020] In this embodiment, the first electrode portion 21 and the second electrode portion 31 may have the same size and shape in a plan view. The planar shape of each electrode portion may be, for example, a circle such as a perfect circle or an ellipse, a polygon, or the like.

[0021] However, without being limited thereto, as will be described in the section on another embodiment below, the planar sizes of these components do not necessarily have to be the same, and the first electrode portion 21 located on the lower layer side may be larger than the second electrode portion 31, and the stretchable substrate located on the lower layer side may be larger than the interlayer sheet. Furthermore, the planar shapes of these components do not necessarily have to be the same.

[0022] The interlayer sheet 40 includes a sheet portion 41 and at least one first via portion 42 provided in the sheet portion 41. As an example, the interlayer sheet 40 may be made of the same material and thickness as the stretchable substrate. In addition, the stretchable substrate and the interlayer sheet may have the same size and shape in plan view. The planar shapes of the stretchable substrate and the interlayer sheet may be, for example, rectangular, square, polygonal, etc.

[0023] Based on the above configuration, the present invention is characterized in that the first via portion 42 partially has a connection region 43 that connects the first electrode portion 21 and the second electrode portion 31 .

[0024] According to this feature, the first via portion 42 has, in addition to the connection region 43, a non-connection region 44 that does not connect the first electrode portion 21 and the second electrode portion 31. That is, in a plan view (when viewed in the thickness direction of the stretchable substrate), the second electrode portion 31 overlaps a part of the first via portion 42.

[0025] From another perspective, in a plan view, the non-connection region 44 of the first via portion 42 is located outside the second electrode portion 31. From yet another perspective, in a plan view, the connection region 43 occupies a part of the first via portion 42.

[0026] As a result, in the present invention, the entire first via portion 42 is not composed of the connection region 43, but rather a portion of the first via portion 42 constitutes the connection region 43, and the remaining portion constitutes a non-connection region 44 that does not connect the first electrode portion 21 and the second electrode portion 31.

[0027] Therefore, the position of the second electrode portion 31 is such that the above-mentioned connection area 43 and non-connection area 44 are provided, and the overall positional relationship between the first via portion 42 and the second electrode portion 31 can be determined.

[0028] This allows the positional accuracy of the first via portion 42 and the second electrode portion 31 to be preferably ensured, and as a result, the connection reliability between the first electrode portion 21 of the first elastic wiring 20 located on the lower side and the second electrode portion 31 of the second elastic wiring 20 located on the upper side can be improved.

[0029] Furthermore, in the stretchable device 100, since the entire device stretches and contracts, misalignment is likely to occur, but even if misalignment does occur, a connection region may be located in the area where the non-connection region was located before the misalignment. Therefore, high connection reliability can be ensured even when the entire device stretches and contracts.

[0030] The stretchable device 100 may further include an adhesive layer. The adhesive layer has adhesiveness that allows the stretchable device 100 to be attached to an adherend such as a living body. In one example, the adhesive layer may be positioned between the stretchable substrate and the adherend such as a living body.

[0031] The adhesive layer has a first main surface facing the adherend, such as a living body, and a second main surface on the opposite side. It is preferable that the first adhesive layer has adhesiveness on both main surfaces. The first main surface of the adhesive layer can be attached to the living body, etc. Note that it is also possible for the first main surface of the adhesive layer itself to be attached to another layer, and then another layer to be attached to the living body, etc. The second main surface of the adhesive layer can be attached to an elastic substrate. Note that a protective layer may further be disposed between the second main surface of the adhesive layer and the elastic substrate from the viewpoint of improving waterproofness, etc.

[0032] The adhesive layer can be made of any adhesive that is mild to the skin, has sufficient pressure-sensitive adhesiveness, and can be easily peeled off from the skin after use.

[0033] Although not particularly limited, the adhesive layer may be composed of a pressure-sensitive adhesive or the like. The pressure-sensitive adhesive is not particularly limited as long as it is one that can be generally used by laminating it on an elastic substrate. For example, rubber-based, acrylic-based, and silicone-based pressure-sensitive adhesives can be used. When a pressure-sensitive adhesive is used, it can be bonded to the mating member (elastic substrate) at a relatively low temperature, so that deterioration and distortion of the elastic substrate can be prevented by using excessive heat or UV energy.

[0034] Second Embodiment Hereinafter, the configuration of a stretchable device 100A according to a second embodiment of the present invention will be described with reference to Fig. 2A. Fig. 2A is a plan view schematically showing the stretchable device according to the second embodiment of the present invention.

[0035] The second embodiment differs from the first embodiment in that the interlayer sheet 40 includes a plurality of via portions 45 .

[0036] The via portions 45 have a planar size smaller than each electrode portion. The planar size of the via portions 45 is also smaller than the width (short dimension) of the extension portion of each wiring. In addition, the via portions 45 can be regularly arranged at predetermined intervals in a plan view on the sheet portion 41. An example of a regular arrangement is a matrix arrangement. In other words, the interlayer sheet 40 has a collection of via portions 45.

[0037] The planar shape of the via portion 45 may be, for example, a circle such as a perfect circle or an ellipse, a polygon, or the like. When the planar shape of the via portion 45 is a circle, its diameter size D1 is, for example, 10 μm or more and 500 μm or less, and may be, for example, 50 μm or more and 300 μm or less in consideration of ease of material filling. Furthermore, when the collection of via portions 45 is arranged in a matrix, its vertical and horizontal dimensions D2 and D3 are, respectively, 2 mm or more and 20 mm or less, and may be, for example, 5 mm.

[0038] Furthermore, the multiple via portions 45 include a second via portion 46 and a third via portion 47 in addition to the first via portion 42 described in the first embodiment. There may be two or more of each of the first to third via portions. In the second embodiment, as in the first embodiment, as shown in FIG. 2A , the first via portion 42 is a via portion that partially has a connection region that connects the first electrode portion 21 and the second electrode portion 31. That is, the first via portion 42 is a via portion that partially overlaps with the second electrode portion 31 in a plan view. In FIG. 2A , the first via portion 42 corresponds to the partially shaded via portion of one via.

[0039] The second via portion 46 may be a via portion that entirely overlaps with the second electrode portion 31 in plan view. In Fig. 2A, the second via portion 46 corresponds to the via portion that is entirely shaded in one via. Note that the second via portion 46 may be a via portion that partially overlaps with the second electrode portion 31 in plan view. Compared to the first via portion 42, the second via portion 46 comprises a connection region that connects the first electrode portion 21 and the second electrode portion 31.

[0040] That is, the second via portion 46 does not need to have a non-connected region that does not connect the first electrode portion 21 and the second electrode portion 31. Moreover, the second via portion 46 is in contact with the second electrode portion 31 and is located below the second electrode portion 31. The presence of such a second via portion 46 can improve the connection reliability between the two electrode portions.

[0041] 2A used in this embodiment and the corresponding FIG. 3E described later, the second via portion located below the second electrode portion is shown with a dotted line to improve understanding of the positional relationship and configuration of the second via portion. In addition to these figures, in drawings related to stretchable devices having second via portions, the second via portion located below the second electrode portion is not shown in consideration of the ease of viewing each drawing.

[0042] The third via portion 47 is a via portion that does not overlap with the second electrode portion 31 in a plan view. In the second embodiment, the third via portion 47 may be a via hole. In Fig. 2A, the third via portion 47 corresponds to the non-shaded via portion of one via.

[0043] As described above, the planar size of the via portion 45 is smaller than the planar size of each electrode portion 21. Therefore, in a planar view, the multiple via portions 45, specifically, the connection regions of the multiple first via portions and the multiple second via portions 46, can be positioned between the first electrode portion 21 and the second electrode portion 31.

[0044] As a result, there are multiple connection regions between the first electrode portion 21 and the second electrode portion 31 that connect these electrode portions together, thereby improving the connection reliability between the first electrode portion 21 and the second electrode portion 31.

[0045] Even if the proportion of the connection area occupied by any one of the multiple second via portions 46 between the first electrode portion 21 and the second electrode portion 31 is small, making it difficult to ensure interlayer connection between the electrode portions at that portion, the presence of multiple other second via portions 46 allows the interlayer connection between the electrode portions to be suitably ensured.

[0046] Furthermore, as described above, the planar size of the via portion 45 is smaller than the width (short dimension) of the extension portion of each wiring, so that breakage starting from the point where the second extension portion 32 of the second elastic wiring 30 overlaps with the edge of the via portion 45 in a planar view can be avoided.

[0047] Furthermore, since there are multiple connection regions between the first electrode portion 21 and the second electrode portion 31 that connect these electrode portions, these multiple connection regions can provide an anchor effect to the second electrode portion 31. This can improve the adhesion between the second electrode portion 31 and the interlayer sheet 40 that has multiple connection regions.

[0048] A method for producing the stretchable device 100A according to the second embodiment will be described below.

[0049] Step 1 Fig. 3A is a plan view schematically showing step 1 of the method for producing a stretchable device according to the second embodiment of the present invention. First, as shown in Fig. 3A, a stretchable substrate 10 is prepared.

[0050] Step 2 Figure 3B is a plan view schematically showing step 2 of the method for producing a stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 3B, after performing step 1, a wiring material is screen-printed on the stretchable substrate 10 using a squeegee or the like, and then dried at about 100°C for a predetermined time. This allows the first stretchable wiring 20 to be formed on the stretchable substrate 10.

[0051] Step 3 Figure 3C is a plan view schematically showing step 3 of the method for producing a stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 3C, after step 2 is performed, a substrate 40a to be used as an interlayer sheet is prepared. This substrate 40a may be the same as the stretchable substrate 10 described above. Thereafter, a laser is irradiated onto this substrate 40a at predetermined intervals to form via holes 45a having a regular arrangement, such as a matrix arrangement. As the laser, for example, a carbon dioxide laser can be used.

[0052] As described above, the planar shape of the via hole 45a may be, for example, a circle such as a perfect circle or an ellipse, a polygon, etc. When the planar shape of the via hole 45a is a circle, its diameter size D1 may be, for example, 10 μm or more and 500 μm or less. Furthermore, when the group of via holes 45a is arranged in a matrix, its vertical and horizontal dimensions D2 and D3 may be, for example, 2 mm or more and 20 mm or less.

[0053] Step 4 Figure 3D is a plan view schematically showing step 4 of the method for producing a stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 3D, after step 3 is performed, the base material 40a prepared in the same step is bonded to the stretchable base material 10 with the first stretchable wiring 20. An example of a bonding method is dry lamination using a vacuum press.

[0054] Step 5 Figure 3E is a plan view schematically showing step 5 of the method for producing a stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 3E, after step 4 is performed, as in step 2, a wiring material is screen-printed using a squeegee or the like at predetermined locations on the substrate 40a serving as an interlayer sheet so as to enable interlayer connection with the first electrode portion 21 of the first stretchable wiring 20 through the via hole 45a. This is then dried at approximately 100°C for a predetermined time. This allows the second stretchable wiring 30 to be formed on the obtained interlayer sheet 40.

[0055] In this specification, the through holes formed in the substrate 40a at an intermediate stage of fabrication are referred to as via holes 45a, and at the completed stage of fabrication, they are referred to as via portions 45. As described above, the distinction between these terms is based on the fact that the obtained via portions 45 include the first via portion 42 (partially filled with wiring material), the second via portion 46 (fully filled with wiring material), and the third via portion (not filled with wiring material and remaining in the state of a via hole).

[0056] In this manner, the stretchable device 100A according to the second embodiment can be fabricated.

[0057] [Modification of Second Embodiment] Hereinafter, the configuration of a modification of the stretchable device according to the second embodiment of the present invention will be described with reference to Fig. 2B. Fig. 2B is a plan view schematically showing the modification of the stretchable device according to the second embodiment of the present invention.

[0058] The modified example of the second embodiment differs from the second embodiment in that the via portion 45 already has a conductive material 48 therein. The conductive material may be the same as the wiring material described above. The fact that a conductive material is already provided in the via portion 45 means that, at a stage before the second stretchable wiring is formed, a conductive material is already provided in at least the portion that will become the second via portion that may overlap with the second electrode portion, in addition to the portion that will become the third via portion. In FIG. 2B, the third via portion 47 after formation corresponds to a via portion that is overall shaded in a different direction than the second via portion 46 shown in FIG. 2A.

[0059] This makes it possible to avoid insufficient filling of the wiring material (corresponding to the conductive material) into the via portion. It also makes it easier to detect insufficient filling of such material. Note that, before the second stretchable wiring is formed, the conductive material does not need to be provided in advance in the portion that can become the first via portion.

[0060] A method for producing the stretchable device 100B according to the second embodiment (a modified example of the second embodiment) will be described below. Note that the description of the same parts as those described in the section on the method for producing the stretchable device 100A will be omitted or simplified.

[0061] 4A is a plan view schematically showing step 1 of the method for producing the modified stretchable device according to the second embodiment of the present invention. First, as shown in FIG. 4A, a stretchable substrate 10 is prepared.

[0062] Step 2 Figure 4B is a plan view schematically showing step 2 of the method for producing a modified stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 4B, after performing step 1, a wiring material is screen-printed on the stretchable substrate 10, and then dried. This allows the first stretchable wiring 20 to be formed on the stretchable substrate 10.

[0063] Step 3: FIG. 4C is a plan view schematically illustrating step 3 of the method for fabricating a modified stretchable device according to the second embodiment of the present invention. Next, as shown in FIG. 4C, after step 2 is performed, a substrate 40a to be used as an interlayer sheet is prepared. A laser is then irradiated onto this substrate 40a at predetermined intervals to form a plurality of regularly arranged via holes 45a. Furthermore, a conductive material is then filled into predetermined locations of the plurality of via holes 45a. For example, a filling method can be used to fill the via holes with a conductive material by screen printing. Regarding the filling locations, at least the portions that will become the third via portion and the second via portion in the final device are filled with a conductive material in advance.

[0064] Step 4 Figure 4D is a plan view schematically showing step 4 of the method for producing a modified example of the stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 4D, after step 3 is performed, the base material 40a prepared in the same step is bonded to the stretchable base material 10 with the first stretchable wiring 20. After bonding the base material 40a, a conductive material may be filled into predetermined locations of the plurality of via holes 45a.

[0065] Step 5 Figure 4E is a plan view schematically showing step 5 of the method for producing a modified stretchable device according to the second embodiment of the present invention. Next, as shown in Figure 4E, after step 4 is performed, as in step 2, a wiring material is screen-printed at predetermined locations on the substrate 40a serving as an interlayer sheet so as to enable interlayer connection with the first electrode portion 21 of the first stretchable wiring 20 through the via hole 45a. This is then dried. As a result, a second stretchable wiring 30 can be formed on the obtained interlayer sheet 40.

[0066] In this manner, the stretchable device 100B according to the second embodiment can be fabricated.

[0067] Third Embodiment Hereinafter, the configuration of a stretchable device 100C according to a third embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a plan view schematically showing the stretchable device according to the third embodiment of the present invention.

[0068] The stretchable device 100C in the third embodiment has basically the same configuration as that in the first embodiment. A difference from the first embodiment is, for example, that the planar size of the second electrode portion 31C of the second stretchable wiring 30C is smaller than the planar size of the first electrode portion 21C of the first stretchable wiring 20C, as shown in Fig. 5 .

[0069] In this case, as in the first embodiment, a part of the first via portion 42 forms the connection region 43, and the remaining portion forms the non-connection region 44 that does not connect the first electrode portion 21C and the second electrode portion 31C. Therefore, the second electrode portion 31C is positioned so that the above-mentioned connection region 43 and non-connection region 44 are provided, and the positional relationship between the first via portion 42 and the second electrode portion 31C can be determined as a whole.

[0070] This allows the positional accuracy of the first via portion 42 and the second electrode portion 31C to be preferably ensured, and as a result, the connection reliability between the first electrode portion 21C of the first elastic wiring 20C located on the lower side and the second electrode portion 31C of the second elastic wiring 30C located on the upper side can be improved.

[0071] Furthermore, in the finally obtained stretchable device, a part of the first via portion 42 constitutes the connection region 43, and the remaining part constitutes the non-connection region 44 that does not connect the first electrode portion 21C and the second electrode portion 31C, so that when the second stretchable wiring is formed during the production of the stretchable device, the wiring material is formed so as not to cover or overlap the entire via hole in a planar view. This makes it possible to secure an escape route for the air located in the via hole, and to suppress the occurrence of residual air bubbles (also called smears) in the via portion including the connection region 43 made of the obtained wiring material (equivalent to the conductive material).

[0072] [Modification 1 of Third Embodiment] Hereinafter, the configuration of modification 1 of the stretchable device according to the third embodiment of the present invention will be described with reference to Figs. 6A and 6B.

[0073] Fig. 6A is a plan view schematically showing a first modification of the stretchable device according to the third embodiment of the present invention, and Fig. 6B is a cross-sectional view schematically showing the structure between A-A in Fig. 6A.

[0074] Modification 1 is characterized in that, in plan view, the non-connected region 44D of the first via portion 42D extends from the second electrode portion 31D toward the edge portion 41DI of the interlayer sheet 40D. Also, as shown in the figure, each of the first stretchable wiring 20D and the second stretchable wiring 30D has two or more electrode portions 21D, 31D.

[0075] This feature allows the orientation of the non-connection region 44D of the first via portion 42D to be uniform. It also makes it easier to ensure a sufficient size of the non-connection region 44D between the electrode portion and the edge portion 41DI of the interlayer sheet 40D. As a result, the positional relationship between the first via portion 42D and the second electrode portion 31D can be made clearer. This allows for more appropriate positional accuracy between the first via portion 42D and the second electrode portion 31D.

[0076] Furthermore, when forming the second stretchable wiring 30D during the production of the stretchable device 100D, it becomes easier to secure an escape route for the air located in the via hole, and the occurrence of air bubbles remaining in the via portion including the connection region 43D made of the resulting wiring material (equivalent to the conductive material) can be further suppressed.

[0077] [Modification 2 of Third Embodiment] Hereinafter, the configuration of modification 2 of the stretchable device according to the third embodiment of the present invention will be described with reference to Figs. 7A and 7B.

[0078] Fig. 7A is a plan view schematically showing a modified example 2 of the stretchable device according to the third embodiment of the present invention, and Fig. 7B is a cross-sectional view schematically showing the structure between B-B in Fig. 7A.

[0079] The second modification is characterized in that, in plan view, the non-connected region 44E of the first via portion 42E continues from the second electrode portion 31E to the edge portion 41EI of the interlayer sheet 40E.

[0080] According to this feature, the interlayer sheet 40E is partially divided, starting from the non-connected region 44E of the first via portion 42E. As a result, when an expansion and contraction force acts in the direction of the arrow shown in FIG. 7A, the expansion and contraction force is less likely to act on the expandable wiring located in the center of the stretchable device 100E in a planar view. This makes it possible to suppress expansion and contraction of the wiring, thereby reducing changes in wiring resistance. Furthermore, when forming a via in this portion, cutting debris is less likely to remain in the via portion. This makes it easier to ensure the size of the via portion is the specified size.

[0081] [Modification 3 of Third Embodiment] Hereinafter, the configuration of modification 3 of the stretchable device according to the third embodiment of the present invention will be described with reference to FIGS. 8A to 8C.

[0082] Fig. 8A is a plan view schematically showing a third modification of the stretchable device according to the third embodiment of the present invention. Fig. 8B is a cross-sectional view schematically showing the structure between A-A in Fig. 8A. Fig. 8C is a cross-sectional view schematically showing the structure between B-B in Fig. 8A.

[0083] Variation 3 is characterized in that, in plan view, the edge 41FI of the interlayer sheet 40F is located inside the edge 10FI of the stretchable substrate 10F. This feature makes the planar size of the interlayer sheet 40F smaller than the planar size of the stretchable substrate 10F. Therefore, high precision is not required when joining the interlayer sheet 40F to the stretchable substrate 10F, which is advantageous in terms of manufacturing efficiency. Furthermore, in a stretchable device, even if there is external contact in the longitudinal extension direction of the substrate, direct contact of the interlayer sheet 40F can be avoided.

[0084] [Variation 4 of Third Embodiment] Hereinafter, the configuration of Variation 4 of the stretchable device according to the third embodiment of the present invention will be described with reference to FIGS. 9A to 9C.

[0085] Fig. 9A is a plan view schematically showing a fourth modification of the stretchable device according to the third embodiment of the present invention. Fig. 9B is a cross-sectional view schematically showing the structure between A-A in Fig. 9A. Fig. 9C is a cross-sectional view schematically showing the structure between B-B in Fig. 9A.

[0086] Variant 4 is characterized in that three or more elastic wires are arranged in the thickness direction of the elastic substrate 10G, and the electrode portions of adjacent elastic wires are connected to each other through the first via portion 42G of the interlayer sheet 40G.

[0087] As an example, as shown in the figure, the stretchable device 100G has, in the thickness direction of the stretchable substrate 10, a first stretchable wiring 20G, a second stretchable wiring 30G, and a third stretchable wiring 50G arranged between the first stretchable wiring 20G and the second stretchable wiring 30G.

[0088] According to this feature, even when three or more elastic wires are arranged, between two adjacent elastic wires, a part of the first via portion 42G forms a connection region 43G, and the remaining part forms a non-connection region 44G that does not connect the first electrode portion 21G and the second electrode portion 31G. Therefore, the positional relationship between the first via portion 42G and the second electrode portion 31G can be determined as a whole. This makes it possible to preferably ensure the positional accuracy between the first via portion 42G and the second electrode portion 31G.

[0089] Furthermore, when forming the upper stretchable wire of two adjacent stretchable wires during the production of a stretchable device, the wiring material is formed so as not to cover or overlap the entire via hole in plan view, thereby ensuring an escape route for air located in the via hole and suppressing the occurrence of residual air bubbles (also called smears) in the via portion including the connection region 43G made of the resulting wiring material (corresponding to the conductive material).

[0090] [Fifth Modification of Third Embodiment] Hereinafter, the configuration of a fifth modification of the stretchable device according to the third embodiment of the present invention will be described with reference to FIGS. 10A to 10C.

[0091] Fig. 10A is a plan view schematically showing a fifth modified example of the stretchable device according to the third embodiment of the present invention. Fig. 10B is a cross-sectional view schematically showing the structure between A-A in Fig. 10A. Fig. 10C is a cross-sectional view schematically showing the structure between B-B in Fig. 10A.

[0092] The fifth modification is characterized in that two or more first via portions 42H are provided with non-connection regions 44H that are offset from one another in plan view, as compared with the fourth modification.

[0093] Since there is no wiring material or conductive material in the non-connection region 44H of the first via portion 42H, when three or more stretchable wirings are arranged in the thickness direction of the stretchable substrate 10H, if the non-connection regions 44H of two or more first via portions 42H are positioned so as to overlap each other in a planar view, the thickness of the interlayer sheet in the local region is likely to become uneven compared to the thickness of other regions.

[0094] In this regard, according to the above-mentioned feature, the non-connected regions 44H of two or more first via portions 42H are positioned in a mutually offset relationship when viewed in a plane, thereby preventing the thickness of a local region of the interlayer sheet from becoming uneven compared to the thickness of other regions.

[0095] [Sixth Modification of Third Embodiment] Hereinafter, the configuration of a sixth modification of the stretchable device according to the third embodiment of the present invention will be described with reference to FIGS. 11A and 11B.

[0096] Fig. 11A is a plan view schematically showing a sixth modification of the stretchable device according to the third embodiment of the present invention, and Fig. 11B is a cross-sectional view schematically showing the structure between A-A in Fig. 11A.

[0097] The sixth modification is characterized in that a plurality of first via portions 42I are located below a single first electrode portion 31I in plan view.

[0098] According to this feature, since there are multiple first via portions 42I, the area of ​​the connection region 43I can be made larger than when there is a single via portion. This makes it possible to further improve the reliability of interlayer connection. Furthermore, when producing a stretchable device, it is possible to reduce the hurdles of the required accuracy for alignment when joining the interlayer sheet 40I to the stretchable substrate 10I and the positional accuracy of the second stretchable wiring formed at a predetermined location on the interlayer sheet 40I.

[0099] [Seventh Modification of Third Embodiment] Hereinafter, the configuration of a seventh modification of the stretchable device according to the third embodiment of the present invention will be described with reference to FIGS. 12A and 12B.

[0100] Fig. 12A is a plan view schematically showing a seventh modification of the stretchable device according to the third embodiment of the present invention, and Fig. 12B is a cross-sectional view schematically showing the structure between A-A in Fig. 12A.

[0101] 12A, in consideration of ease of viewing the drawing, the diagram mainly emphasizes the arrangement and structure of the internal multiple stretchable wires located between the first stretchable wire 20J and the second stretchable wire 30J. That is, in FIG. 12A, the second stretchable wire is omitted from the illustration.

[0102] Variant 7 is similar to variant 4 in that three or more elastic wires are arranged in the thickness direction of the elastic substrate 10J, but the internal elastic wires 70J, 80J located between the first elastic wire 20J and the second elastic wire 30J are located in multiple positions in the longitudinal extension direction of the interlayer sheet 40J.

[0103] In one example, a small area stretchable wire (70J, 80J) is disposed inside the device between two large area stretchable wires (20J, 30J) in the thickness direction of the stretchable substrate (10J). These stretchable wires (70J, 80J) can be disposed in parallel at a predetermined interval on the interlayer sheet (40J).

[0104] Some of the stretchable wirings 70J are interlayer connected to the first stretchable wiring 20J and the second stretchable wiring 30J via the connection regions of the via portions, respectively. Meanwhile, the remaining stretchable wirings 80J are not connected to the first stretchable wiring 20J and the second stretchable wiring 30J, and function as separate and independent wirings. In other words, the remaining stretchable wirings 80J located inside function as stretchable wirings that do not come into contact with the first via portion 42J.

[0105] According to such a feature, the first stretchable wire and the second stretchable wire can block noise that may enter the internal stretchable wire. In addition, two or more types of wires or wire groups having different functions can be provided in one stretchable device 100J, which is advantageous in that it can enrich the device functions.

[0106] Hereinafter, a description will be given of a method for manufacturing the stretchable device 100C according to the third embodiment (basic mode) shown in Fig. 5. Note that the description of parts that overlap with the contents of the method for manufacturing the stretchable device already described will be omitted or simplified.

[0107] Step 1 Fig. 13A is a plan view schematically showing step 1 of the method for producing a stretchable device according to the third embodiment of the present invention. First, as shown in Fig. 13A, a stretchable substrate 10 is prepared.

[0108] Step 2 Fig. 13B is a plan view schematically showing step 2 of the method for producing a stretchable device according to the third embodiment of the present invention. Next, as shown in Fig. 13B, after step 1 is performed, a wiring material is screen-printed on the stretchable substrate 10, and then dried. This allows a first stretchable wiring 20 to be formed on the stretchable substrate 10.

[0109] Step 3 Fig. 13C is a plan view schematically showing step 3 of the method for producing a stretchable device according to the third embodiment of the present invention. Next, as shown in Fig. 13C, after performing step 2, a base material 40b to be used as an interlayer sheet is prepared. Thereafter, a laser is irradiated onto this base material 40b to form via holes 45b.

[0110] 13D is a plan view schematically showing step 4 of the method for producing a stretchable device according to the third embodiment of the present invention. Next, as shown in Fig. 13D, after step 3 is performed, the base material 40b prepared in the same step is bonded to the stretchable base material 10 with the first stretchable wiring 20.

[0111] Step 5 Figure 13E is a plan view schematically showing step 5 of the method for producing a stretchable device according to the third embodiment of the present invention. Next, as shown in Figure 13E, after step 4 is performed, as in step 2, a wiring material is screen-printed using a squeegee at predetermined locations on the substrate 40b serving as an interlayer sheet so as to enable interlayer connection with the first electrode portion 21C of the first stretchable wiring 20C through the via hole 45b. This is then dried. This allows a second stretchable wiring 30C to be formed on the obtained interlayer sheet 40.

[0112] Specifically, in this manufacturing method, in the stretchable device finally obtained in step 5, a portion of the first via portion 42 forms a connection region 43, and the remaining portion forms a non-connection region 44 that does not connect the first electrode portion 21C and the second electrode portion 31C. In this manner, the wiring material is printed and applied so as not to cover or overlap the entire via hole in a planar view.

[0113] This ensures an escape route for air located in the via hole, and prevents air bubbles from remaining in the via portion, including the connection region 43 made of the resulting wiring material (corresponding to the conductive material), (also called smearing).

[0114] In this manner, the stretchable device 100C according to the third embodiment can be fabricated.

[0115] Note that each embodiment and modification is an example, and the present invention is not limited to each embodiment and modification. Also, each drawing is an example of components, and does not limit the shape. Furthermore, partial substitution or combination of the configurations shown in different embodiments and modifications is possible.

[0116] A stretchable device according to an embodiment of the present invention may take the following forms. <1> A stretchable device comprising: a stretchable substrate; a first stretchable wire disposed on the stretchable substrate and having a first electrode portion; a second stretchable wire disposed on the first stretchable wire and having a second electrode portion; and an interlayer sheet disposed between the first stretchable wire and the second stretchable wire, wherein the interlayer sheet includes a sheet portion and at least one first via portion provided in the sheet portion, and the first via portion partially has a connection region connecting the first electrode portion and the second electrode portion. <2> The stretchable device according to <1>, wherein the second electrode portion overlaps a portion of the first via portion in a planar view. <3> The stretchable device according to <1> or <2>, wherein the first via portion further has, in addition to the connection region, a non-connection region that does not connect the first electrode portion and the second electrode portion. <4> The stretchable device according to <3>, wherein, in a plan view, the non-connection region of the first via portion is located outside the second electrode portion. <5> The stretchable device according to any one of <1> to <4>, wherein, in a plan view, the connection region occupies a part of the first via portion. <6> The stretchable device according to any one of <1> to <5>, wherein, in a plan view, the interlayer sheet further has at least one second via portion that entirely overlaps with the second electrode portion. <7> The stretchable device according to <6>, wherein the second via portion consists of the connection region. <8> The stretchable device according to any one of <1> to <7>, wherein, in a plan view, the interlayer sheet further has a third via portion that does not overlap with the second electrode portion. <9> The stretchable device according to <6> or <7>, wherein the interlayer sheet has a plurality of via portions that are regularly arranged at predetermined intervals in the sheet portion, and the plurality of via portions include the first via portion and the second via portion. <10> The stretchable device according to <9>, wherein the plurality of via portions are arranged in a matrix. <11> The stretchable device according to <9> or <10>, wherein diameters of the plurality of via portions are smaller than diameters of the first electrode portion and the second electrode portion. <12> The stretchable device according to <8>, wherein the third via portion is a via hole or a via portion having a conductive material therein.<13> The stretchable device according to any one of <3> to <5>, wherein, in a plan view, the non-connected region of the first via portion extends from the second electrode portion toward an edge of the interlayer sheet. <14> The stretchable device according to <13>, wherein, in a plan view, the non-connected region of the first via portion continues from the second electrode portion to the edge of the interlayer sheet. <15> The stretchable device according to <13>, wherein, in a plan view, the edge of the interlayer sheet is located more inward than an edge of the stretchable substrate. <16> The stretchable device according to any one of <1> to <5>, wherein three or more of the stretchable wires are arranged in a thickness direction of the stretchable substrate, and an electrode portion of one adjacent stretchable wire and an electrode portion of the other adjacent stretchable wire are connected to each other through the first via portion of the interlayer sheet. <17> The stretchable device according to <16>, wherein, when the three or more stretchable wires are arranged, two or more first via portions are provided, the non-connection regions of which are shifted in plan view. <18> The stretchable device according to <16> or <17>, wherein, when the three or more stretchable wires are arranged, there is a stretchable wire that does not contact the first via portion. <19> The stretchable device according to any of <16> to <18>, wherein, when the three or more stretchable wires are arranged, a stretchable wire having a small area area is arranged between two stretchable wires having large area areas in the thickness direction of the stretchable substrate. <20> The stretchable device according to <19>, wherein the stretchable wires having small area areas are arranged in parallel at a predetermined interval on the interlayer sheet.

[0117] 100, 100A to 100J: Stretchable device 10, 10A to 10J: Stretchable substrate 20, 20C to 20J: First stretchable wiring 21, 21C to 21I: First electrode portion 22, 22C to 22G: First extension portion 30, 30C to 30J: Second stretchable wiring 31, 31C to 31I: Second electrode portion 32, 32C to 32H: Second extension portion 40, 40D to 40G, 40I, 40J: Interlayer sheet 40a, 40b: Base material 41, 41D to 41J: Sheet portion 41DI to 41FI: Edge portion of interlayer sheet 42, 42D to 42I: First via portion 43, 43D to 43I: Connection region 44, 44D to 44F: Non-connection region 45: Via portion 45a, 45b: Via hole 46: Second via portion 47: Third via portion 48: Conductive material 50G, 50H Third elastic wire 51G, 51H Electrode portion of third elastic wire 60G, 60H, 60J Protective layer 70J, 80J Internal elastic wire 71J Electrode portion of internal elastic wire 72J Extension portion of internal elastic wire

Claims

1. A stretchable substrate, a first stretchable wire disposed on the stretchable substrate and having a first electrode portion, a second stretchable wire disposed on the first stretchable wire and having a second electrode portion, and an interlayer sheet disposed between the first stretchable wire and the second stretchable wire, the interlayer sheet includes a sheet portion and at least one first via portion provided in the sheet portion; The stretchable device, wherein the first via portion partially has a connection region that connects the first electrode portion and the second electrode portion.

2. The stretchable device according to claim 1 , wherein the second electrode portion overlaps a portion of the first via portion in a plan view.

3. The stretchable device according to claim 1 or 2, wherein the first via portion further has, in addition to the connection region, a non-connection region that does not connect the first electrode portion and the second electrode portion.

4. The stretchable device according to claim 3 , wherein the non-connected region of the first via portion is located outside the second electrode portion in a plan view.

5. 2. The stretchable device of claim 1, wherein, in a plan view, the connection region occupies a portion of the first via portion.

6. 10. The stretchable device according to claim 1, wherein, in a plan view, the interlayer sheet further has at least one second via portion that entirely overlaps the second electrode portion.

7. 7. The stretchable device of claim 6, wherein the second via portion consists of the connection region.

8. The stretchable device according to claim 1 , wherein the interlayer sheet further has a third via portion that does not overlap with the second electrode portion in a plan view.

9. The stretchable device according to claim 6, wherein the interlayer sheet has a plurality of via portions regularly arranged at predetermined intervals in the sheet portion, and the plurality of via portions include the first via portion and the second via portion.

10. The stretchable device according to claim 9 , wherein the plurality of via portions are arranged in a matrix.

11. The stretchable device according to claim 9 , wherein diameters of the plurality of via portions are smaller than diameters of the first electrode portion and the second electrode portion.

12. 9. The stretchable device according to claim 8, wherein the third via portion is a via hole or a via portion having a conductive material therein.

13. 4. The stretchable device according to claim 3, wherein, in a plan view, the non-connected region of the first via portion extends from the second electrode portion toward an edge of the interlayer sheet.

14. The stretchable device according to claim 13, wherein, in a plan view, the non-connected region of the first via portion continues from the second electrode portion to an edge of the interlayer sheet.

15. The stretchable device according to claim 13, wherein an edge of the interlayer sheet is located inside an edge of the stretchable substrate in a plan view.

16. 2. The stretchable device according to claim 1, wherein three or more of the stretchable wirings are arranged in the thickness direction of the stretchable substrate, and an electrode portion of one of the adjacent stretchable wirings and an electrode portion of the other of the adjacent stretchable wirings are connected to each other through the first via portion of the interlayer sheet.

17. 17. The stretchable device according to claim 16, wherein when the three or more stretchable wirings are arranged, two or more first via portions are provided in which the non-connection regions are shifted in plan view.

18. The stretchable device according to claim 16, wherein when the three or more stretchable wires are arranged, the stretchable wires do not contact the first via portion.

19. 17. The stretchable device according to claim 16, wherein, when the three or more stretchable wires are arranged, a stretchable wire having a small area is arranged between two stretchable wires having a large area in the thickness direction of the stretchable substrate.

20. 20. The stretchable device according to claim 19, wherein the small-area stretchable wiring is arranged in parallel at predetermined intervals on the interlayer sheet.