Stretchable device

Abstract

Provided is a stretchable device that comprises: a structure that includes a plurality of stretchable base material layers and a plurality of pieces of stretchable wiring; and connection wiring that connects at least two pieces of the plurality of pieces of stretchable wiring. The structure has: a layering region at which the plurality of stretchable base material layers and the plurality of pieces of stretchable wiring are layered; and a connection region that coincides with the connection wiring as seen from the layering direction. The at least two pieces of stretchable wiring are at different positions in the layering direction in the layering region.

Description

stretchable devices

[0001] The present disclosure relates to stretchable devices.

[0002] Stretchable devices in which stretchable wiring is mounted on a stretchable substrate have been known for some time. These stretchable devices can be used by being worn on the human body, for example.

[0003] Patent Document 1 describes a resin substrate having a multilayer structure in which a plurality of resin layers are laminated and conductive patterns are provided as wiring on the main surfaces of the resin layers.

[0004] Patent No. 6205834

[0005] The resin substrate of Patent Document 1 has multiple resin layers laminated on its main surfaces, each having a conductor pattern as wiring. Two conductor patterns formed on different resin layers are connected by a via conductor provided so as to penetrate the resin layer located between the conductor patterns.

[0006] The inventors of the present application have noticed that there are issues to be overcome when applying the above-described interlayer wiring connections to a stretchable device having a multilayer structure in which multiple stretchable substrate layers are stacked, and have newly discovered the need to take measures to address these issues.

[0007] Specifically, when via conductors are formed in a stretchable device, the portions including the via conductors become locally hard and difficult to stretch. This results in a non-uniform stretch rate throughout the stretchable device. This makes it easier for stress to concentrate near the via conductors when the stretchable device is stretched, potentially damaging components of the stretchable device, such as the stretchable substrate layer and stretchable wiring.

[0008] The present disclosure has been made in view of such problems. That is, a main object of the present disclosure is to provide a stretchable device in which stretchable wirings arranged at different positions in the stacking direction are more suitably connected to each other.

[0009] In order to achieve the above object, in one embodiment of the present disclosure, there is provided a stretchable device comprising: a structure including a plurality of stretchable substrate layers and a plurality of stretchable wirings; and a connecting wiring in contact with at least two of the plurality of stretchable wirings; wherein the structure comprises a stacking region having the plurality of stretchable substrate layers and the plurality of stretchable wirings stacked on each other; and a connecting region that overlaps with the connecting wiring when viewed from the stacking direction; and wherein each of the at least two stretchable wirings is arranged in the stacking region at a different position from each other in the stacking direction.

[0010] According to the stretchable device according to an embodiment of the present disclosure, stretchable wires that are arranged at different positions in the stacking direction are more suitably connected to each other.

[0011] FIG. 1 is a schematic plan view of a stretchable device according to a first embodiment of the present disclosure. FIG. 2A is a cross-sectional view of the stretchable device shown in FIG. 1 , taken along line A-A. FIG. 2B is a cross-sectional view of the stretchable device shown in FIG. 1 , taken along line B-B. FIG. 3A is a cross-sectional view of the stretchable device shown in FIG. 1 , taken along line C-C. FIG. 3B is a cross-sectional view of the stretchable device shown in FIG. 1 , taken along line D-D. FIG. 3C is a cross-sectional view of the stretchable device shown in FIG. 1 , taken along line E-E. FIG. 4A is a schematic plan view of a stretchable substrate layer and a stretchable wiring according to a first embodiment of the present disclosure. FIG. 4B is a schematic plan view of a stretchable substrate layer and a stretchable wiring according to a first embodiment of the present disclosure. FIG. 4C is a schematic plan view of a stretchable substrate layer and a stretchable wiring according to a first embodiment of the present disclosure. FIG. 4D is a schematic plan view of a stretchable substrate layer according to a first embodiment of the present disclosure. FIG. 5 is a schematic side view for explaining a method for manufacturing a stretchable device according to a first embodiment of the present disclosure. FIG. 6 is a schematic plan view of a stretchable device according to a first embodiment of the present disclosure. Fig. 7 is a cross-sectional view of the stretchable device shown in Fig. 6 taken along line F-F. Fig. 8 is a schematic plan view of a stretchable device according to a second modified example of the second embodiment of the present disclosure. Fig. 9 is a cross-sectional view of the stretchable device shown in Fig. 8 taken along line F-F. Fig. 10 is a cross-sectional view of the stretchable device according to the second embodiment of the present disclosure taken along line A-A. Fig. 11A is a cross-sectional view of the stretchable device according to the second embodiment of the present disclosure taken along line C-C. Fig. 11B is a cross-sectional view of the stretchable device according to the second embodiment of the present disclosure taken along line D-D. Fig. 11C is a cross-sectional view of the stretchable device according to the second embodiment of the present disclosure taken along line E-E.

[0012] 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.

[0013] In this specification, the terms "thickness direction of the stretchable device," "thickness direction of the stretchable substrate layer," "stacking direction of the stretchable substrate layer," and "stacking direction" may be used interchangeably. Such a direction corresponds to direction X in the drawings.

[0014] As used herein, the term "cross-sectional view" or "cross-sectional shape" refers to the shape of the stretchable device as viewed from a direction substantially perpendicular to the thickness direction (in other words, the shape of the stretchable device cut along a plane parallel to the thickness direction). When the stretchable device has a layered structure including multiple stretchable substrate layers, the term "cross-sectional view" or "cross-sectional shape" refers to the shape of the stretchable device as viewed from a direction substantially perpendicular to the stacking direction of the stretchable substrates (in other words, the shape of the stretchable device cut along a plane parallel to the stacking direction). Furthermore, the term "planar view" used herein refers to a sketch of the object as viewed from above or below along the thickness direction (or stacking 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 through another object or a position above the element with a space between them, 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 will be described with reference to Fig. 1, Fig. 2A, and Fig. 2B. Fig. 1 is a plan view schematically showing a stretchable device 100 according to a first embodiment of the present disclosure. Fig. 2A is a cross-sectional view taken along the line A-A of the stretchable device 100 in Fig. 1. Fig. 2B is a cross-sectional view taken along the line B-B of the stretchable device 100 in Fig. 1. Note that the cross-sectional views in this specification are cross-sections parallel to the thickness direction X of the stretchable device 100. In other words, they are cross-sections perpendicular to the stretching direction of the stretchable wire 20. Even when making actual comparisons, this can be confirmed by the above-mentioned cross-sectional view at any position of the stretchable wire 20 stretching in a certain direction.

[0017] The stretchable device 100 mainly comprises a structure 50 including a stretchable substrate layer 10 and a stretchable wiring 20 provided on the main surface of the stretchable substrate layer 10. The stretchable device 100 may further comprise a member such as a connection substrate 40 provided on the structure 50. That is, the term "stretchable device" in the present disclosure collectively refers to a composite product including a structure 50 including a stretchable substrate layer 10 and a stretchable wiring 20, and members provided on the structure 50. Note that, although the drawings such as FIG. 1 show a stretchable device extending in a specific direction for the sake of clarity, the shape of the stretchable device is not particularly limited.

[0018] The arrangement of the main components included in the stretchable device of the present disclosure will be described below with reference to Figures 1, 2A, and 2B. As shown in Figures 1, 2A, and 2B, in the structure 50 of the stretchable device 100, stretchable wiring 20 is provided on the main surface 11 of the stretchable substrate layer.

[0019] (Stretchable substrate 10) The stretchable substrate layer 10 (hereinafter also simply referred to as "substrate") is a sheet-like or film-like stretchable substrate, and is made of, for example, a stretchable resin material. Here, in this specification, stretchability simply means the property of being able to stretch and contract, and can also be referred to as stretchability, stretchable, etc. More specifically, it means the property of being able to stretch from a non-stretched state, which is the normal state in which no tensile stress is applied, by applying tensile stress, and being able to contract when released from the stretched state. Examples of resin materials used as the stretchable substrate layer include thermoplastic polyurethane.

[0020] The stretchable substrate layers 10 may be stacked one on top of another in the thickness direction. More specifically, the plurality of stretchable substrate layers 10a to 10d may have a multilayer structure in which they are stacked with their main surfaces facing each other. In other words, the plurality of stretchable substrate layers 10a to 10d may form a multilayer structure by being stacked in the thickness direction X of the stretchable substrate layers. Furthermore, although the drawing exemplarily shows a stretchable device 100 in which four stretchable substrate layers are stacked, the number of stacked stretchable substrate layers 10 is not particularly limited.

[0021] The thickness of the stretchable substrate layer 10 is not particularly limited, but from the viewpoint of not inhibiting the expansion and contraction of the surface of an adherend such as a living body when attached to the adherend, it is preferably 1 mm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. The thickness of the stretchable substrate layer is preferably 1 μm or more. The stacked stretchable substrate layers 10a to 10d may each have the same thickness or different thicknesses.

[0022] (Stretchable Wiring 20) The stretchable wiring 20 (hereinafter also simply referred to as "wiring") 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 in shape.

[0023] Furthermore, for the sake of clarity, FIG. 1 depicts only wires extending in a specific direction, but the stretchable wires 20 may extend in any direction on the main surface of the stretchable substrate layer 10. Furthermore, when viewed from the thickness direction X of the stretchable substrate layer 10, the stretchable wires 20 do not necessarily have to be arranged in a straight line, and may be arranged, for example, in a curved line. Furthermore, when viewed from the thickness direction X, the stretchable wires 20 do not necessarily have to extend in one direction. The number of stretchable wires 20 is not particularly limited, and multiple stretchable wires 20 may be arranged. For example, one or two or more stretchable wires may be arranged on the main surface of one stretchable substrate layer 10.

[0024] When the structural body 50 of the stretchable device has a multilayer structure formed by stacking a plurality of stretchable substrate layers 10, the stretchable wiring 20 may be disposed inside the multilayer structure. FIGS. 4A to 4D are plan views of each of the stretchable substrate layers 10a to 10d included in the stretchable device shown in FIG. 1 . As shown, the stretchable wiring 20 is positioned on the main surface 11 of the stretchable substrate layer 10, and the stretchable substrate layers 10 may be stacked on top of each other so that the stretchable wiring 20 is located inside the multilayer structure of the stretchable substrate layer 10. In other words, a plurality of stretchable substrate layers 10 may be stacked with the stretchable wiring 20 sandwiched between them. This structure can also be interpreted as a plurality of stretchable substrate layers 10 being stacked so that the stretchable wiring 20 disposed on the main surface of one stretchable substrate layer 10 is sandwiched between the other stretchable substrate layers 10. That is, inside a multilayer structure formed by stacking a plurality of stretchable substrate layers 10, the stretchable wiring 20 may be sandwiched between the plurality of stretchable substrate layers 10 stacked on top of each other.

[0025] (Adhesive Layer) Although not shown, the stretchable device 100 may further include an adhesive layer provided on the outer surface. The adhesive layer has adhesiveness that allows the stretchable device 100 to be attached to an adherend.

[0026] The stretchable device can be attached to an adherend, such as a living body, via an adhesive layer. Therefore, any adhesive can be used as the adhesive layer, as long as it is mild to the skin, has sufficient pressure-sensitive adhesive properties, and can be easily peeled off from the skin after use. While merely illustrative, examples of adhesive layers include synthetic rubber-based adhesives, acrylic-based adhesives, urethane-based adhesives, natural rubber-based adhesives, and silicone-based adhesives, with synthetic rubber-based adhesives being more preferred. Furthermore, from the viewpoint of adaptability to the shape and movement of the living body surface, it is preferable that the adhesive layer have excellent stretchability and flexibility.

[0027] (Characteristic Portions of the First Embodiment) Based on the details of the main components of the stretchable device described above, the characteristic portions of the first embodiment of the present disclosure will be described below. As shown in FIGS. 1 , 2A, and 2B, the stretchable device 100 of the present disclosure comprises a structure 50 including a stretchable substrate layer 10 and a stretchable wiring 20, and a connection wiring 30 provided on the structure 50. The structure 50 has a stacking region I including a plurality of stretchable substrate layers 10a-10d and a plurality of stretchable wirings 20a-20c stacked on top of each other, and a connection region II having an overlap with the connection wiring 30 when viewed from the stacking direction. In this specification, the "stacking direction" refers to the stacking direction of the stretchable substrate layer 10 and corresponds to the thickness direction X of the stretchable substrate layer. In the connection region II, which is a partial region of the structure 50, the structure 50 has an overlap with the connection wiring 30 when viewed from the stacking direction X. Therefore, the structure 50 can also be considered a composite structure having the stacking region I and the connection region II.

[0028] Fig. 2B corresponds to a cross-sectional view of the structure 50 in a stacking region I, and Fig. 2A corresponds to a cross-sectional view of the structure 50 in a connection region II. Furthermore, Figs. 3A to 3C correspond to cross-sectional views taken along the extension direction of the stretchable wires for each of the stretchable wires 20a to 20c arranged in the stretchable device 100. As shown in the figures, the structure 50 has different structures in the stacking region I and the connection region II. The multiple stretchable wires 20 and the multiple stretchable substrate layers 10 may extend across the stacking region I and the connection region II.

[0029] Specifically, in the laminated region I, a plurality of stretchable substrate layers 10 are laminated on top of each other, and a plurality of stretchable wires 20 are disposed between the stretchable substrate layers 10 ( FIG. 2A ). At least two of the plurality of stretchable wires 20 are located between different stretchable substrate layers 10. That is, of the plurality of stretchable wires 20, at least two of the stretchable wires 20 are disposed at different positions in the thickness direction X of the stretchable substrate layers. The plurality of stretchable wires 20 located between different stretchable substrate layers 10 may be disposed so that at least a portion of them overlap each other when viewed from the lamination direction X of the stretchable substrate layers, or may not overlap each other. That is, the plurality of stretchable wires 20 located between different stretchable substrate layers 10 may be disposed so as to be offset from each other in the width direction of the stretchable wires 20.

[0030] On the other hand, in connection region II of the structure 50, the stretchable substrate layer 10 and the stretchable wiring 20 may be arranged in a position different from that in the stacking region I. Furthermore, the stretchable device 100 includes, in connection region II of the structure 50, a connection wiring 30 that is different from the stretchable wiring 20 arranged inside the stacking region I. The connection wiring 30 may be provided so as to join with the structure 50 in the connection region II. For example, when viewed from the stacking direction X of the stretchable substrate layer, the connection wiring 30 may be arranged so as to overlap with the structure 50 in the connection region II. In this regard, it can also be understood that the portion of the structure 50 where the connection wiring 30 is provided is the connection region II, and the remaining majority is the stacking region I.

[0031] The stretchable wiring 20 may extend so as to straddle from the stacking region I to the connection region II. The stretchable wiring 20 arranged in the stacking region I extends across the connection region II and contacts the connecting wiring 30. In other words, the connecting wiring 30 provided in the connection region II of the structure 50 may be in contact with the stretchable wiring 20 extending from the stacking region I to the connection region II at the connection region II. Each of at least two stretchable wirings 20 arranged in different positions in the stacking direction X of the stretchable substrate layer in the stacking region I contacts the connecting wiring 30 at the connection region II. In other words, the connecting wiring 30 may be in contact with each of the multiple stretchable wirings 20a to 20c at multiple locations and be electrically connected to each other.

[0032] For example, as shown in FIGS. 1 to 2B , a stretchable device 100 includes a plurality of stretchable substrate layers 10, a first stretchable wiring 20a, and a second stretchable wiring 20b, and the first stretchable wiring 20a and the second stretchable wiring 20b are arranged in different positions in a stacking region I with respect to the stacking direction X of the stretchable substrate layers. Each of the first stretchable wiring 20a and the second stretchable wiring 20b extends from the stacking region I to the connection region II and comes into contact with a connecting wiring 30 provided in the connection region II. That is, each of the first stretchable wiring 20a and the second stretchable wiring 20b arranged between different stretchable substrate layers 10 in the stacking region I extends toward and comes into contact with the connecting wiring 30 provided in the connection region II. This electrically connects each of the first stretchable wiring 20a and the second stretchable wiring 20b to the connecting wiring 30.

[0033] According to the above-described configuration, the stretchable wirings 20 connected to the connecting wirings 30 can be electrically connected to each other via the connecting wirings 30. That is, at least two stretchable wirings 20 arranged at different positions in the stacking direction X of the stretchable substrate layers can be electrically connected to each other via the connecting wirings 30. This means that the stretchable wirings 20 located between different stretchable substrate layers 10 can be connected to each other without using via conductors that penetrate the stretchable substrate layers 10. That is, according to the present disclosure, the stretchable wirings 20 located between different stretchable substrate layers 10 can be more suitably connected to each other without locally reducing the elongation rate of the stretchable device 100 due to the presence of via conductors.

[0034] Furthermore, according to the above-described structure, in the stacking region I, there is no connection between the multiple stretchable wires 20 arranged at different positions relative to the stacking direction X, while in the connection region II, the stretchable wires 20 can be connected to each other. Specifically, in the stacking region I, the multiple stretchable wires 20a to 20c arranged at different positions relative to the stacking direction X of the stretchable substrate layer are insulated from each other by the stretchable substrate layer 10, while in the connection region II, they may come into contact with the connecting wire 30 and thereby achieve electrical connection via the connecting wire 30. In this way, the connecting wire 30 plays a role in relaying the electrical connection of the multiple stretchable wires 20, and may also be referred to as a "relay wire," an "interconnect wire," a "bridge wire," or the like.

[0035] Therefore, according to the present disclosure, in the stacking region I, it is not necessary to connect the stretchable wirings 20 that straddle the stretchable substrate layers 10, but rather the multiple stretchable wirings 20a to 20c arranged between different stretchable substrate layers 10 can be electrically connected via contact with the connecting wiring 30 provided in the connection region II. As a result, the stretchable device 100 has contact portions between the wirings that can change the elongation rate in the connection region II, while in the stacking region I, the stretchable substrate layers 10 and the stretchable wirings 20 can be uniformly arranged along the extension direction of the stretchable device without having such contact portions. Therefore, the stretchable device can have a more uniform elongation rate in the stacking region I.

[0036] In this way, by gathering the contact portions of the wires into one region, it is possible to make the elongation rate in other regions more uniform. Therefore, the stretchable device 100 of the present disclosure has a structure that combines a stacking region I having a more uniform elongation rate and a connection region II having a structure for connecting the wires. The stretchable device of the present disclosure can also be understood as having a composite structure that includes a stretching region I that enables more uniform stretching and a connection region II that is responsible for connecting the wires.

[0037] Furthermore, with the above-described structure, it is possible to suitably electrically connect stretchable wires 20 that do not overlap each other when viewed from the stacking direction X of the stretchable substrate layers. For example, in a connection using via conductors, the via conductors are provided so as to penetrate the stretchable substrate layers 10, and therefore the connected stretchable wires 20 need to be arranged so as to overlap each other when viewed from the stacking direction X. On the other hand, in the present disclosure, by connecting each of the multiple stretchable wires 20 located between different stretchable substrate layers 10 to the connecting wire 30 in the connection region II, it is possible to indirectly electrically connect the stretchable wires 20 to each other without using via conductors. Therefore, the arrangement of the stretchable wires 20 in the structure 50 is not limited. For example, it is possible to arrange the multiple stretchable wires 20 so that they do not overlap each other when viewed from the stacking direction X of the stretchable substrate layers 10.

[0038] When multiple stretchable wires 20 are arranged so as to overlap each other as viewed from the stacking direction X of the stretchable substrate layers, the thickness of the stretchable device 100 may increase locally at the locations where the stretchable wires 20 overlap. The elongation rate may be reduced in locations with a larger thickness compared to locations with a smaller thickness, which may result in a non-uniform elongation rate of the stretchable device 100. According to the present disclosure, multiple stretchable wires 20 can be arranged offset from each other as viewed from the stacking direction X of the stretchable substrate layers. This allows the stretchable device 100 to have a more uniform thickness and a more uniform elongation rate. That is, according to the present disclosure, a stretchable device can be provided that can suitably connect stretchable wires 20 located between different stretchable substrate layers 10 while achieving a more uniform elongation rate.

[0039] The connection region II where the stretchable wiring 20 and the connecting wiring 30 are in contact may be an end region of the structure 50 (see FIG. 1 ). That is, the structure 50 may have a connection region II in at least one end region, and a stacking region I in regions other than the connection region II. The end region may be, for example, a region located on one end side of the structure in the stretching direction of the stretchable device. For example, the connection region II may be provided at one end of the structure 50, and the stacking region I may be in the other regions. Alternatively, the structure 50 may have connection regions II on both ends, and the other main regions may be stacking regions I. By providing the connection region II on the end side, there is no connection between the wires in the main regions other than the end side, and more suitable stretchability can be achieved.

[0040] In one embodiment, the stacking region I and the connection region II may be continuous with each other. In other words, the connection region II may be a region continuous with the stacking region I. That is, when viewed from the stacking direction X, the connection wiring 30 may overlap with the structure 50 in the region II continuous with the stacking region I.

[0041] Such a structure can also be interpreted as a structure in which the stacking region I and the connection region II partially overlap when viewed from the stacking direction X. In other words, a portion of the stacking region I and a portion of the connection region II may overlap each other when viewed from the stacking direction X. This can be interpreted as a structure in which a plurality of stretchable substrate layers 10 and a plurality of stretchable wires 20 have a stacked structure, and which overlaps with the connecting wires 30 when viewed from the stacking direction X. In other words, the connecting wires 30 may overlap with the structure 50 in the stacking region I of the stretchable substrate layers 10 and the stretchable wires 20.

[0042] By configuring the stacking region I and the connection region II so that they are continuous with each other, or so that they overlap each other, the stacking region I and the connection region II can be arranged closer to each other. This allows the stretchable device to be made more compact while providing a suitable connection structure between the wires. On the other hand, a region that does not correspond to either the stacking region I or the connection region II may be interposed between the stacking region I and the connection region II. Specifically, this is a region that does not overlap with the connecting wires when viewed from the stacking direction, and has a single layer of wire. In such a region, for example, wiring may be routed, or electronic devices such as sensors may be disposed.

[0043] Furthermore, the stretchable wiring 20 and the connecting wiring 30 may be connected by contacting the ends of the wirings. More specifically, the connection between the stretchable wiring 20 and the connecting wiring 30 may be achieved by contacting the end of the stretchable wiring 20 with the end of the connecting wiring 30. For example, when viewed from the stacking direction X of the stretchable substrate layer, the end of the connecting wiring 30 and the end of the stretchable wiring 20 may be in contact so as to overlap each other. The stretchable wiring 20 can be partially restricted in stretch by providing a connection portion 21 with the connecting wiring 30 only at the end, while the stretchable wiring 20 can be suitably stretched in a portion other than the end because it does not have a connection portion with the connecting wiring 30. In other words, by connecting the wirings end-to-end, it is possible to more suitably suppress a reduction in the stretchability of the stretchable wiring 20 due to connection.

[0044] As described above, the connecting wire 30 may be joined to the structure 50 in the connection region II when viewed from the stacking direction X so as to overlap each other. In such a structure, the connecting wire 30 has a joining surface 35 with the structure 50. The stretchable wire 20 may be in contact with the connecting wire 30 at this joining surface 35. That is, for each of at least two stretchable wires 20 arranged at different positions from each other in the stacking direction X, a connection portion 21 that contacts the connecting wire 30 can be disposed at the joining surface 35 of the connecting wire 30 joined to the structure 50. For example, each of at least two stretchable wires 20 arranged at different positions from each other in the stacking direction X in the stacking region I may be in contact with the connecting wire 30 on the same plane in the connection region II. In other words, for each of at least two stretchable wires 20 arranged between different stretchable substrate layers 10, the connection portion 21 with the connecting wire 30 may be located on the same plane.

[0045] This allows the connection of the stretchable wirings 20 located between different stretchable substrate layers 10 to be carried out on the same plane without the need for via conductors. Therefore, it is possible to provide a stretchable device that can more suitably connect the stretchable wirings 20 located between different stretchable substrate layers 10 without reducing the elongation rate due to the presence of via conductors.

[0046] The connection wiring 20 provided in the connection region II can have any wiring pattern (see FIGS. 6 and 7 ). Therefore, the stretchable wirings 20 connected to the connection wiring 30 can be electrically connected to each other according to the wiring pattern of the connection wiring 30. This makes it possible to electrically connect multiple stretchable wirings 20 connected to the connection wiring 30 in any desired manner. For example, when a connection of the stretchable wiring 20 across the stretchable substrate layer 10 (i.e., an interlayer connection) is made using a via conductor, a longer via conductor must be installed to connect stretchable wirings 20 located between layers that are further apart from each other. However, a longer via conductor not only locally reduces the elongation rate but may also result in poor connection reliability. Therefore, with conventional connection methods using via conductors, it can be difficult to connect wirings located between separated layers. According to the present disclosure, by forming the wiring pattern of the connection wiring 30 in any desired pattern, it becomes possible to easily electrically connect not only the stretchable wirings 20 located between adjacent stretchable substrate layers but also the stretchable wirings 20 located between stretchable substrate layers that are farther apart.

[0047] The connecting wire 30 may extend toward the outside of the structure 50. When viewed from the stacking direction X of the stretchable substrate layer, the connecting wire 30 may have a portion that overlaps with the structure 50 and a portion that is located outside the structure 50 and does not overlap with the structure 50. That is, the connecting wire 30 may be joined to the structure 50 so that it overlaps only in part. The connecting wire 30 may have a wiring pattern, in a portion that extends outside the structure 50, for connecting at least two stretchable wires 20 connected to the connecting wire 30. This means that the stretchable wires 20 connected to the connecting wire 30 can be electrically connected to each other at a position separated from the structure 50. In other words, the stretchable wires 20 can be electrically connected to each other outside the structure 50, rather than inside the structure 50.

[0048] As shown in Figure 3A, when the stretchable wiring 20 in the stacking region I and the connection wiring 30 in the connection region II are arranged at the same position in the stacking direction X, the stretchable wiring 20 extending across from the stacking region I to the connection region II may extend along the extension direction of the stretchable device 100.

[0049] 3B and 3C , at least one of the stretchable wires 20 among the multiple stretchable wires 20a to 20c may have the stretchable wire 20 in the stacking region I and the connecting wire 30 in the connection region II arranged at different positions in the stacking direction X. In this case, in a cross-sectional view, the stretchable wire 20 extending from the stacking region I to the connection region II may have a curved portion that bends toward the connecting wire 30 in the vicinity of the connection region II. That is, in a cross-sectional view, the stretchable wire 20 does not extend in one direction from the stacking region I to the connection region II, but may extend in directions different from each other in the stacking region I and the connection region II. Specifically, the stretchable wire 20 has a first portion 22 that extends along the extension direction of the stretchable substrate layer 10 in the stacking region I, and a second portion 24 that is continuous with the first portion 22 and extends toward the connecting wire 30. When the stretchable wiring 20 in the stacking region I and the connection wiring 30 in the connection region II are arranged at different positions in relation to the stacking direction X, the stretchable wiring 20 may extend in different directions in the first part 22 and the second part 24.

[0050] For example, the stretchable wires 20b and 20c may extend in a direction perpendicular to the stacking direction X of the stretchable substrate layers in the first portion 22, while extending obliquely relative to the stacking direction X in the second portion 24. That is, in a cross-sectional view, the stretchable wire 20 extends along the extension direction of the stretchable device in the stacking region I, and then extends obliquely relative to the stacking direction X of the stretchable substrate layers toward the connection wire 30 provided in the connection region II, and may come into contact with the connection wire 30. According to this structure, the multiple stretchable wires 20 located between different stretchable substrate layers 10 in the stacking region I extend so as to converge on the connection wire 30 in the connection region II. This allows the connection wire 30 to function as a hub for electrically connecting the multiple stretchable wires 20a to 20c to each other. As described above, the connection wire 30 can form any wiring pattern outside the structure 50. Therefore, according to the present disclosure, it is possible to realize a more complex connection structure between stretchable wires compared to a structure in which via conductors are provided.

[0051] The connection portion 21 of the stretchable wiring 20 that is in contact with the connecting wiring 30 may be covered by the stretchable substrate layer 10. Here, the "connection portion 21" of the stretchable wiring 20 refers to a portion of the stretchable wiring 20 that is in contact with the connecting wiring 30. For example, the connection portion 21 of the stretchable wiring 20 with the connecting wiring 30 may be covered by the stretchable substrate layer 10 that extends from the stacking region I. The stretchable substrate layer 10 may extend from the stacking region I to the connection region II together with the stretchable wiring 20, and cover the connection portion 21.

[0052] In a cross-sectional view, the stretchable substrate layer 10 covering the connection portion 21 of the stretchable wires may be a single layer or multiple layers. Furthermore, in a cross-sectional view, the number of layers of the stretchable substrate layer 10 covering the connection portion 21 at each connection portion 21 of a plurality of stretchable wires 20 does not have to be the same. That is, in a cross-sectional view, the thickness of the structure 50 in the connection region II does not have to be constant. For example, the connection region II of the structure 50 includes connection portions 21 of a plurality of stretchable wires that contact the connecting wires 30, and the thickness of the structure 50 at each connection portion 21 may be different.

[0053] 2A , in a cross-sectional view, the structure 50 in the connection region II may have a stepped structure by varying the thickness in the region where each connection portion 21 is located. Such a stepped structure may be formed by varying the number of layers of the stretchable substrate layer 10 covering each connection portion 21.

[0054] 3A to 3C are cross-sectional views showing the cross-sectional shape of the stretchable wire 20 located between different stretchable substrate layers 10. As shown in the drawings, in the lamination region I, the connection portion 21 of the stretchable wire 20 may be covered by the stretchable substrate layer 10 that is located on the opposite side to the connecting wire 30 and that is laminated on the stretchable wire 20. For example, when the connecting wire 30 is provided on the underside of the structure 50, the connection portion 21 of the stretchable wire 20 may be covered by one or more stretchable substrate layers 10 that are laminated on the stretchable wire 20 in the lamination region I.

[0055] For example, as shown in Figure 3A, in the stacking region I, three stretchable substrate layers 10a-10c are located on the opposite side of the stretchable substrate layer 10d with respect to the connecting wire 20a and are laminated on the connecting wire 30, and may cover the connection portion 21 of the stretchable wire 20a. Similarly, as shown in Figure 3B, two stretchable substrate layers 10b and 10c are located on the opposite side of the connecting wire 30 in the stacking region I and are laminated on the stretchable wire 20b, and may cover the connection portion 21 of the stretchable wire 20b. Similarly, as shown in Figure 3C, one stretchable substrate layer 10c is located on the opposite side of the connecting wire 30 in the stacking region I and is laminated on the stretchable wire 20c, and may cover the connection portion 21 of the stretchable wire 20c.

[0056] This structure can also be interpreted as realizing contact of the stretchable wiring 20 with the connecting wiring 30 by removing the stretchable substrate layer 10 located on the connecting wiring 30 side in the connection region II. Therefore, in the stretchable wiring 20 arranged distally from the connecting wiring 30 in the stacking region I, a larger amount of the stretchable substrate layer 10 is removed in the connection region II, so the thickness of the structure 50 can be smaller. Therefore, in a cross-sectional view, the thickness of the structure 50 at the connection portion 21 of the stretchable wiring 20 located more proximal to the connecting wiring 30 in the stacking region I may be greater than the thickness of the structure 50 at the connection portion 21 of the stretchable wiring 20 extending more distally from the connecting wiring 30 in the stacking region I. This allows the stretchable wiring 20 extending in the connection region II to come into contact with the connecting wiring 30, and the connection portion 21 where the stretchable wiring 20 comes into contact with the connecting wiring 30, to be suitably covered by the stretchable substrate layer 10. Therefore, the stretchable wiring 20 and the connection portion 21 of the stretchable wiring are suitably protected, and damage to the stretchable wiring 20 and the connection portion 21 due to the stretching of the stretchable device 100 can be suppressed.

[0057] The contact portions of the stretchable wiring 20 and the connecting wiring 30 may be bonded by thermal fusion, or alternatively, may be electrically and mechanically joined using solder, conductive resin, and / or a conductive adhesive such as an anisotropic conductive film (ACF).

[0058] The stretchable device of the present disclosure may further include a connection substrate 40. The connection substrate 40 may include a main surface 45 that supports the connection wiring 30. In other words, the connection wiring 30 may be disposed on the main surface 45 of the connection substrate. For example, a wiring pattern of the connection wiring 30 may be provided on the main surface 45 of the connection substrate. Such a connection substrate 40 may be provided in the connection region II of the structure 50. More specifically, the connection substrate 40 may be joined to the connection region II of the structure 50 so that a portion of the main surface 45 of the connection substrate overlaps with the structure 50 when viewed from the stacking direction X of the stretchable base material layer. The connection portion 21 of the stretchable wiring may be positioned on the main surface 45 of the connection substrate. By including a connection substrate 40 that supports the connection wiring 30 in the stretchable device 100, contact between the stretchable wiring 20 and the connection wiring 30 is more suitably supported. This can further improve the connection reliability between the wirings.

[0059] The connection substrate 40 may extend from the connection region II of the structure to the exterior of the structure 50. For example, the connection substrate 40 and the structure 50 may be joined so as to overlap each other at their respective end regions. In other words, the structure 50 may be joined so as to overlap the end region of the connection substrate 40 at the connection region II. In such a structure, the connection substrate 40 may have an overlapping region that overlaps when viewed from the stacking direction X of the stretchable substrate layer, and a non-overlapping region that does not overlap each other. The overlapping region is understood to be the region where the stretchable substrate layer 10 constituting the structure 50 and the connection substrate 40 are joined, and may also be referred to as an "inter-substrate joining region." The connection wiring 30 arranged on the connection substrate 40 may form a wiring pattern on the main surface 45 of the connection substrate so as to extend from the overlapping region to the non-overlapping region.

[0060] The connection substrate 40 may be made of a stretchable material. For example, the connection substrate 40 may be made of the same material as the stretchable substrate layer 10, or may be made of a different material. By using a stretchable material for the connection substrate 40, the stretchable device 100 of the present disclosure can be made stretchable as a whole. As the stretchable material, a resin material having the same stretchability as the stretchable substrate layer 10 described above may be used. The stretchable substrate layer 10 and the connection substrate 40 may be made of the same material, or may be made of different materials.

[0061] When the connection substrate 40 is made of a stretchable material, the connection wiring 30 provided on the connection substrate 40 is preferably stretchable. As the material for the stretchable connection wiring 30, a mixture containing conductive particles and a resin may be used, similar to the above-described stretchable wiring 20. The stretchable wiring 20 and the connection wiring 30 may be made of the same material, or may be made of different materials.

[0062] Alternatively, the connection substrate 40 may be formed from a non-stretchable insulating material. That is, the connection substrate 40 may be a non-stretchable substrate. Here, "non-stretchable" includes not only those that do not stretch at all, but also those that stretch sufficiently little compared to stretchable materials to be considered non-stretchable. In other words, it may also include those that have some stretchability. Examples of non-stretchable insulating materials include glass composite substrates such as CEM3, glass cloth-based epoxy resins such as FR4, and thermoplastic resins used in flexible substrates. Examples of thermoplastic resins include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides (PA) such as nylon 6-10 and nylon 46, polyether ether ketone (PEEK), acryl butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC). The connection substrate 40 may also be a rigid substrate.

[0063] Since the connection substrate 40 is made of a non-stretchable material, the region where the stretchable wiring 20 and the connection wiring 30 contact each other is non-stretchable. This makes the contact between the stretchable wiring 20 and the connection wiring 30 less susceptible to the effects of tensile stress caused by the stretching of the stretchable device 100, thereby suppressing breakage at the contact point between the wirings. Furthermore, when the connection substrate 40 is made of a non-stretchable material, it is preferable that the connection substrate 40 and the structure 50 do not overlap in the stacking region I of the structure 50 when viewed from the stacking direction X. That is, the stretchable device may include a stretchable region in the stacking region I and a non-stretchable region in the connection region II. By combining the non-stretchable regions into one region, the elongation rate of the stacking region I can be made more uniform. Furthermore, in the connection region II of the structure 50, contact between the stretchable wiring 20 and the connection wiring 30 is favorably supported. As a result, a stretchable device with superior connection reliability and favorable stretchability can be provided.

[0064] When the connection substrate 40 is made of a non-stretchable material, the connection wiring formed on the connection substrate 40 may be made of a non-stretchable material. Examples of non-stretchable materials include metal foils such as copper foil and aluminum foil.

[0065] FIG. 8 is a schematic plan view showing a stretchable device 101 according to a modified example of an embodiment of the present disclosure. FIG. 9 is a cross-sectional view of the stretchable device 101 shown in FIG. 8 taken along line F-F. As shown in the figure, when the connection substrate 40 is made of a non-stretchable material, vias 32 that connect the connection wires 30 may be formed in the connection substrate 40. That is, a wiring pattern of the connection wires 30 including the vias 32 may be formed in the connection substrate 40. More specifically, a plurality of connection wires 30 may be provided on the main surface 45 of the connection substrate 40, and the plurality of connection wires 30 may be electrically connected to each other via the vias 32. A plurality of stretchable wires 20 arranged at different positions relative to the stacking direction X of the stretchable substrate layer may contact the connection wires 30 on the connection substrate 40 and be electrically connected to each other via the connection wires 30 and vias 32 formed in the wiring pattern of the connection wires 30. This improves the degree of freedom in the wiring pattern of the connecting wires 30, making it possible to connect multiple stretchable wires 20 located between different stretchable substrate layers 10 in a more complex manner.

[0066] Furthermore, by providing the vias 32, it is possible to further reduce the area required to form the wiring pattern of the connection wiring 30. This makes it possible to miniaturize the stretchable device. Furthermore, in the stretchable device, since the non-stretchable region including the connection region II of the structure can be further reduced, it may be possible to ensure a relatively large area for the stretchable stacked region I.

[0067] (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.

[0068] First, the stretchable substrate layer 10 is prepared. After the stretchable substrate layer 10 is prepared, stretchable wiring 20 is formed on the main surface 11 of the stretchable substrate layer 10 (see FIGS. 4A to 4D ). As shown in FIGS. 4A to 4D , each stretchable substrate layer 10 may have a different shape. Specifically, when multiple stretchable substrate layers 10 each equipped with stretchable wiring 20 are stacked, a portion of the end of the stretchable substrate layer 10 may be cut out so that the end of the stretchable wiring 20 formed in each stretchable substrate layer 10 is exposed on the main surface facing the connecting wiring. In other words, the stretchable substrate layer 10 may have a shape in which a portion of the end is cut out so that the end of the stretchable wiring 20 formed in the stretchable substrate layers 10 stacked on top of each other is exposed. Such a cutout structure enables each of the multiple stretchable wirings 20 located between different stretchable substrate layers to come into contact with the connecting wiring 30.

[0069] 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 makes it possible to obtain a desired circuit pattern.

[0070] After forming a circuit pattern of the stretchable wiring 20 on the stretchable substrate layer 10, the conductive paste for the stretchable wiring is dried and cured to form the stretchable wiring on the stretchable substrate layer. Note that printing may be performed not only on one wiring main surface, but also on both the first wiring main surface and the second wiring main surface that face each other. It is also possible to mount components on the stretchable wiring as needed.

[0071] Similarly, a connection substrate 40 is prepared, and connection wiring 30 is formed on a main surface 45 of the connection substrate 40 (see FIG. 5 ). The connection wiring 30 may be formed on the connection substrate 40 in accordance with a known method for manufacturing a printed wiring board. For example, the connection wiring may be formed by a method using a printing technique, or a method using sputtering or plating.

[0072] Next, the stretchable substrate layers 10 on which the desired circuit patterns have been formed by printing are stacked in the thickness direction X of the stretchable substrate layers (see FIG. 5 ). Furthermore, a connection substrate 40 is stacked on top of the stacked stretchable substrate layers 10. At this time, each member is arranged so that each of the multiple stretchable wires 20 exposed in the cut-out areas of the stretchable substrate layer 10 is positioned on the connection wires 30 on the connection substrate 40. In other words, the stretchable substrate layers 10 and the connection substrate 40 are stacked so that the exposed portions of the stretchable wires 20 and the connection wires 30 face each other.

[0073] Thereafter, the stacked stretchable substrate layers 10 are pressed under a predetermined temperature condition with a predetermined pressure, thereby obtaining a stretchable device of the present disclosure. By pressing the stacked stretchable substrate layers 10 along the stacking direction X, in the connection region, the exposed plurality of stretchable wires 20 are pressed against the connecting wires 30 together with the stretchable substrate layers 10 located above the stretchable wires 20. As a result, the plurality of stretchable wires 20 arranged opposite the connecting wires 30 and the stretchable substrate layers 10 located above the stretchable wires 20 are pressed and bent toward the connecting wires 30. The bent stretchable wires 20 come into contact with the connecting wires 30, and the contact portions are covered by the stretchable substrate layers 10. As a result, the plurality of stretchable wires 20 located between different layers are held in contact with the connecting wires 30.

[0074] Furthermore, particularly when the connection substrate 40 is a non-stretchable substrate, the structure 50 and the connection substrate 40 may be joined by an adhesive. Furthermore, the stretchable wiring 20 and the connection wiring 30 may be electrically and mechanically joined using solder, a conductive resin, and / or a conductive adhesive such as ACF.

[0075] In this manner, a stretchable device according to an embodiment of the present disclosure can be fabricated.

[0076] Second Embodiment Next, a description will be given of a stretchable device 200 according to a second embodiment. The stretchable device 200 differs from the stretchable device 100 according to the first embodiment in that the connection substrate 40 has a step in cross-sectional view.

[0077] FIG. 10 is a cross-sectional view of a stretchable device 200 according to the second embodiment. This cross-sectional view corresponds to a schematic diagram of a cross section of the stretchable device 200 according to the second embodiment, cut at the same location as the A-A cross section of the stretchable device 100 shown in FIG. 1. As shown in FIG. 10, in the stretchable device 200 according to the second embodiment, the connection substrate 40 includes a plurality of step surfaces 42 that differ in height from one another in the stacking direction X of the stretchable base material layer. The connection substrate 40 and the structure 50 are bonded to one another at the step surfaces 42. In other words, the connection substrate 40 may include a plurality of step surfaces 42 that differ in thickness from one another on its main surface 45 that is bonded to the structure 50. A connection wiring 30 may be provided on each step surface 42. The stretchable wiring 20 included in the structure 50 may be in contact with the connection wiring 30 located on each of the step surfaces 42 of the connection substrate. Therefore, when viewed in cross section, the connection portions 21 with the connecting wiring 30 of each of the multiple elastic wirings 20 located between different elastic substrate layers 10 are not arranged on the same plane, but are arranged at different positions from each other in the stacking direction X.

[0078] 11A to 11C are cross-sectional views of the stretchable device 200 according to the second embodiment taken along the extension direction of the stretchable wiring 20. These cross-sectional views correspond to schematic cross-sectional views of the stretchable device 200 according to the second embodiment taken at the same locations as the CC cross-section, the DD cross-section, and the EE cross-section of the stretchable device 100 shown in FIG. 1, respectively. As shown in FIGS. 11A to 11C, each of the multiple stretchable wirings 20a to 20c arranged at different positions from one another in the stacking direction X of the stretchable substrate layer extends toward the connection wiring 30 provided on the step surface 42. By having the step surface 42 in the connection substrate 40, the connection wiring 30 and the stretchable wiring 20 can be arranged at the same position in the stacking direction X of the stretchable substrate layer. In other words, a step surface 42 may be formed on the connection substrate 40 so that the connection wiring 30 and each of the elastic wirings 20 arranged between the elastic substrate layers 10 can be positioned at the same position with respect to the stacking direction X of the elastic substrate layers.

[0079] With the above-described configuration, the stretchable wire 20 extending from the stacking region I can extend along the extension direction of the stretchable device 200 up to the connection portion 21 with the connecting wire 30 in the connection region II. This means that, compared to the stretchable wire 20 in the first embodiment, the stretchable wire 20 in the second embodiment does not have any curved portions in a cross-sectional view and can extend substantially straight. That is, in the second embodiment, each of the multiple stretchable wires 20a to 20c located between mutually different stretchable substrate layers 10 can extend approximately parallel to each other from the stacking region I to the connection region II in a cross-sectional view. This allows the stretchable wire 20 to be arranged along the elongation direction of the stretchable device even in the connection region II, thereby making the elongation rate of the stretchable device more uniform.

[0080] Furthermore, according to the above-described configuration, the stretchable wiring 20 and the stretchable substrate layer 10 covering the connection portion 21 of the stretchable wiring 20 with the connecting wiring 30 also have no curved portions in a cross-sectional view and can extend substantially straight. That is, in a cross-sectional view, the stretchable substrate layer 10 can extend approximately parallel to one another from the stacking region I to the connection region II. Therefore, as shown in FIG. 10 , the stretchable device 200 can have a uniform thickness in the connection region II. In the first embodiment, a step is formed on the outer surface of the stretchable device 100 in the connection region II of the structure 50 due to the difference in thickness of the structure 50 in each connection portion 21. On the other hand, in the second embodiment, by combining the stretchable device 200 with a connection substrate 40 having a stepped surface 42, the outer surface of the stretchable device 200 can have a substantially uniform flat surface even in the connection region II of the structure 50. The term "substantially uniform plane" here refers to a state in which the degree of step in the structure is reduced by the step surface 42 of the connecting substrate, and includes not only a uniform plane but also a plane containing minute irregularities.

[0081] Although the embodiments of the present disclosure have been described above, they are merely typical examples. Those skilled in the art will readily understand that the present disclosure is not limited thereto, and that various modifications are possible within the scope of the present disclosure.

[0082] It should be noted that one embodiment of the present disclosure as described above includes the following preferred aspects. <1> A stretchable device comprising a structure including a plurality of stretchable substrate layers and a plurality of stretchable wires, and a connecting wire in contact with at least two of the plurality of stretchable wires, wherein the structure comprises a stacking region having the plurality of stretchable substrate layers and the plurality of stretchable wires stacked on top of each other, and a connection region overlapping with the connecting wire when viewed from the stacking direction, and wherein each of the at least two stretchable wires is arranged at a mutually different position in the stacking direction in the stacking region. <2> The stretchable device of <1>, wherein the at least two stretchable wires arranged at mutually different positions in the stacking direction are electrically connected via the connecting wire. <3> The stretchable device of <1> or <2>, wherein, in the structure, the connection region is continuous with the stacking region. <4> The stretchable device according to any one of <1> to <3>, wherein the connecting wiring has a joining surface that is joined to the structure so as to overlap each other in the connection region when viewed from the stacking direction, and each of the at least two stretchable wirings arranged at different positions from each other in the stacking direction has a connecting portion that contacts the connecting wiring at the joining surface. <5> The stretchable device according to <4>, wherein the connecting wiring extends from the connecting portion in each of the at least two stretchable wirings toward the outside of the structure, and has a wiring pattern for electrically connecting the at least two stretchable wirings at a position spaced apart from the structure. <6> The stretchable device according to any one of <1> to <5>, wherein the connection region is arranged in an end region of the structure. <7> The stretchable device according to any one of <1> to <6>, wherein a plurality of the stretchable wirings arranged at different positions from each other in the stacking direction in the stacking region are insulated from each other. <8> The stretchable device according to any one of <1> to <7>, wherein the connecting wiring has a plurality of ends located in the connection region, and an end of each of the at least two stretchable wirings is in end-to-end contact with each of the plurality of ends of the connecting wiring.<9> The stretchable device of any of <1> to <8>, wherein at least one of the stretchable wires among the plurality of stretchable wires includes a first portion extending in the stacking region and a second portion including a connection portion with the connecting wire in the connection region, and the second portion extends in a direction different from that of the first portion. <10> The stretchable device of <9>, wherein the first portion extends in a direction perpendicular to the stacking direction, and the second portion extends obliquely with respect to the stacking direction. <11> The stretchable device of any of <1> to <10>, wherein, in the connection region, at least two of the stretchable wires arranged at different positions in the stacking direction each include a connection portion in contact with the connecting wire, and wherein thicknesses of the structures at each of the connection portions differ from each other in a cross-sectional view. <12> The stretchable device of <11>, wherein, in a cross-sectional view, the thickness of the structure at the connection portion of the stretchable wire located proximal to the connecting wire in the stacked region among the at least two stretchable wires is greater than the thickness of the structure at the connection portion of the stretchable wire located distal to the connecting wire in the stacked region. <13> The stretchable device of any of <1> to <12>, further comprising a connection substrate including a main surface supporting the connecting wire, wherein the connection substrate is joined to the connection region of the structure so that a part of the main surface overlaps the structure when viewed from the stacking direction. <14> The stretchable device of <13>, wherein a wiring pattern of the connecting wire is provided on the main surface of the connection substrate. <15> The stretchable device of <13> or <14>, wherein the connection substrate is a non-stretchable base material. <16> The stretchable device according to <15>, comprising: a plurality of the connection wirings; the connection substrate comprising vias that connect the plurality of connection wirings; and at least two of the stretchable wirings arranged at different positions in the stacking direction are electrically connected to each other via the connection wirings and the vias.<17> The stretchable device of any of <13> to <16>, wherein the main surface of the connecting substrate comprises a plurality of step surfaces having different heights in the stacking direction, each of the plurality of step surfaces comprises the connecting wiring, and each of the at least two stretchable wirings arranged at different positions in the stacking direction is electrically connected to the connecting wiring at each of the plurality of step surfaces. <18> The stretchable device of <17>, wherein the plurality of step surfaces are such that the connecting wiring located on the step surface and the stretchable wiring connected to the connecting wiring extend at the same height in the stacking direction. <19> The stretchable device of <17> or <18>, wherein, in a cross-sectional view, each of the plurality of stretchable wirings connected to the connecting wiring extend parallel to each other from the stacking region to the connection region.

[0083] 100, 200: Stretchable device 10, 10a to 10c: Stretchable substrate 11: Main surface 20, 20a to 20c: Stretchable wiring 21: Connection portion 30: Connection wiring 32: Via 35: Bonding surface 40: Connection substrate 42: Step surface 45: Main surface 50: Structure X: Thickness direction of the stretchable substrate

Claims

1. A stretchable device comprising a structure including a plurality of stretchable substrate layers and a plurality of stretchable wirings, and a connection wiring in contact with at least two of the plurality of stretchable wirings, wherein the structure comprises a stacking region having the plurality of stretchable substrate layers and the plurality of stretchable wirings stacked on top of each other, and a connection region overlapping with the connection wiring when viewed from the stacking direction, and each of the at least two stretchable wirings is arranged in a different position from each other in the stacking direction in the stacking region.

2. The stretchable device according to claim 1, wherein at least two of the stretchable wirings arranged at different positions in the stacking direction are electrically connected via the connection wiring.

3. The stretchable device of claim 1 or 2, wherein in the structure, the connection region is continuous with the stacked region.

4. The stretchable device according to any one of claims 1 to 3, wherein the connection wiring has a joint surface that is joined to the structure so as to overlap each other in the connection region when viewed from the stacking direction, and each of at least two of the stretchable wirings arranged at different positions from each other in the stacking direction has a connection portion that contacts the connection wiring at the joint surface.

5. The stretchable device according to claim 4, wherein the connection wiring extends from the connection portion of each of the at least two stretchable wirings toward the outside of the structure and has a wiring pattern for electrically connecting the at least two stretchable wirings at a position spaced apart from the structure.

6. The stretchable device of any one of claims 1 to 5, wherein the connection regions are disposed at end regions of the structure.

7. The stretchable device according to any one of claims 1 to 6, wherein in the stacked region, a plurality of the stretchable wirings arranged at different positions in the stacking direction are insulated from each other.

8. The stretchable device according to any one of claims 1 to 7, wherein the connecting wiring comprises a plurality of ends located in the connection region, and an end of each of the at least two stretchable wirings is in end-to-end contact with each of the plurality of ends of the connecting wiring.

9. A stretchable device according to any one of claims 1 to 8, wherein at least one of the plurality of stretchable wirings includes a first portion extending in the stacking region and a second portion including a connection portion with the connection wiring in the connection region, and the second portion extends in a direction different from that of the first portion.

10. The stretchable device of claim 9, wherein the first portion extends in a direction perpendicular to the stacking direction, and the second portion extends obliquely to the stacking direction.

11. The stretchable device according to any one of claims 1 to 10, wherein at least two of the stretchable wirings arranged at different positions in the stacking direction in the connection region each have a connection portion in contact with the connection wiring, and the thicknesses of the structures at each of the connection portions are different from each other in a cross-sectional view.

12. The stretchable device according to claim 11, wherein, in a cross-sectional view, a thickness of the structure at the connection portion of the stretchable wiring located proximal to the connection wiring in the stacked region among the at least two stretchable wirings is greater than a thickness of the structure at the connection portion of the stretchable wiring located distal to the connection wiring in the stacked region.

13. The stretchable device according to any one of claims 1 to 12, further comprising a connection substrate including a main surface that supports the connection wiring, the connection substrate being joined to the connection region of the structure such that a portion of the main surface overlaps the structure when viewed from the stacking direction.

14. The stretchable device according to claim 13, wherein a wiring pattern of the connection wiring is provided on the main surface of the connection substrate.

15. The stretchable device of claim 13 or 14, wherein the connecting substrate is a non-stretchable substrate.

16. The stretchable device according to claim 15, comprising a plurality of connection wirings, the connection board comprising vias connecting the plurality of connection wirings, and at least two of the stretchable wirings arranged at different positions with respect to the stacking direction are electrically connected to each other via the connection wirings and the vias.

17. The stretchable device according to any one of claims 13 to 16, wherein the main surface of the connection substrate has a plurality of step surfaces having different heights in the stacking direction, each of the plurality of step surfaces has the connection wiring, and each of the at least two stretchable wirings arranged at different positions in the stacking direction is electrically connected to the connection wiring at each of the plurality of step surfaces.

18. The stretchable device according to claim 17, wherein the plurality of step surfaces are such that the connection wiring located on the step surface and the stretchable wiring connected to the connection wiring extend at the same height as each other in the stacking direction.

19. The stretchable device according to claim 17 or 18, wherein, in a cross-sectional view, each of the multiple stretchable wirings connected to the connection wiring extends parallel to one another from the stacking region to the connection region.

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