stretchable devices

Abstract

This stretchable device comprises: a stretchable first base material; first wiring provided to a first main surface of the first base material; a second base material that faces the first base material in a first direction, which is the thickness direction of the first base material, the second base material being connected to the first base material; second wiring provided to a first main surface of the second base material, the second wiring facing the first wiring in the first direction and being electrically connected to the first wiring; and a first protection layer provided to the first main surface of the first base material so as to cover part of the first wiring. As seen from the first direction, a first overlap region where the first base material and the first protection layer overlap is set apart from a wiring region where the first wiring and the second wiring are electrically connected.

Description

[Technical Field]

[0001] The present disclosure relates to stretchable devices. [Background technology]

[0002] A conventional stretchable device is described in Japanese Patent Application Laid-Open No. 2008-108890 (Patent Document 1). This stretchable device has a first substrate, a first wiring provided on the first substrate, a second substrate facing the first substrate in the thickness direction of the first substrate, a second wiring provided on the second substrate facing the first wiring in the thickness direction, and a connecting member that electrically connects the first wiring and the second wiring. When viewed in the thickness direction, the region where the first wiring and the second wiring overlap and the region where the connecting member is present constitute a wiring region where the first wiring and the second wiring are electrically connected. When viewed in the thickness direction, the wiring region coincides with the substrate overlap region where the first substrate and the second substrate overlap. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-108890 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional stretchable device, if the wiring is exposed to the outside, water droplets or foreign matter may adhere across adjacent wiring, causing a short circuit between the adjacent wiring and damaging the stretchable device. Furthermore, exposure of the metal wiring to air or moisture may cause oxidation or corrosion of the wiring. Therefore, it is considered to cover the surface of the wiring with a protective layer. Specifically, the protective layer is provided on all parts of the first wiring that are exposed from the second substrate. In other words, when viewed from the thickness direction, the wiring region where the first wiring and the second wiring are electrically connected and the protective layer overlap region where the first substrate and the protective layer overlap are adjacent to each other.

[0005] However, it was found that when stretching a stretchable device, there is a risk of damage to the stretchable device, such as breakage of the first wiring, occurring between the wiring region and the protective layer overlap region when viewed from the thickness direction, and there is also a risk of a decrease in the performance of the stretchable device, such as an increase in the resistance value of the first wiring.

[0006] Therefore, an object of the present disclosure is to provide a stretchable device that can reduce damage to the stretchable device when stretching the stretchable device and can also suppress deterioration in the performance of the stretchable device. [Means for solving the problem]

[0007] In order to solve the above problems, a stretchable device according to one aspect of the present disclosure includes: a first base material having elasticity; a first wiring provided on a first main surface of the first base material; a second base material that faces the first base material in a first direction that is a thickness direction of the first base material and is connected to the first base material; a second wiring provided on a first main surface of the second base material, facing the first wiring in the first direction, and electrically connected to the first wiring; a first protective layer provided on the first main surface of the first base material so as to cover a portion of the first wiring; Equipped with When viewed from the first direction, a first overlapping region where the first base material and the first protective layer overlap is separated from a wiring region where the first wiring and the second wiring are electrically connected. [Effects of the Invention]

[0008] According to a stretchable device according to one aspect of the present disclosure, damage to the stretchable device can be reduced when the stretchable device is stretched, and degradation of the performance of the stretchable device can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a partially enlarged top view schematically illustrating a stretchable device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded plan view schematically showing the stretchable device according to the first embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a partial cross-sectional view of a stretchable device according to a second embodiment of the present disclosure. [Figure 5] FIG. 5 is a partial cross-sectional view of a stretchable device according to a third embodiment of the present disclosure. [Figure 6] FIG. 6 is a partial cross-sectional view of a stretchable device according to a fourth embodiment of the present disclosure. [Figure 7] FIG. 7 is a partial cross-sectional view of a stretchable device according to a fifth embodiment of the present disclosure. [Figure 8] FIG. 8 is a partial cross-sectional view of a stretchable device according to a sixth embodiment of the present disclosure. [Figure 9] FIG. 9 is a partial cross-sectional view of a stretchable device according to a seventh embodiment of the present disclosure. [Figure 10] FIG. 10 is a partial cross-sectional view of a stretchable device according to an eighth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] [First embodiment] The structure of a stretchable device 100 according to a first embodiment will be described with reference to Figs. 1, 2, and 3. Fig. 1 is a partial top view of the stretchable device 100. Fig. 2 is an exploded plan view of the stretchable device 100. Fig. 3 is a cross-sectional view of the stretchable device 100 taken along line III-III in Fig. 1. Note that cross-sectional views in this specification are cross-sectional views parallel to the first direction, which is the thickness direction of the first substrate, including the region where the first substrate 1 and the second substrate 3 overlap. The first direction is indicated by a double-headed arrow X. The thickness direction of the first substrate 1, the thickness direction of the second substrate 3, and the first direction X coincide with each other.

[0012] The stretchable device 100 comprises a first substrate 1, a second substrate 3, a first wiring 2, a second wiring 4, and a first protective layer 6. The first substrate 1 and the second substrate 3 are connected to each other. The first wiring 2 provided on the first main surface 1a of the first substrate 1 and the second wiring 4 provided on the first main surface 3a of the second substrate 3 are electrically connected to each other. The first protective layer 6 is provided on the first main surface 1a of the first substrate 1 so as to cover a portion of the first wiring 2.

[0013] The shape of the stretchable device 100 is not particularly limited. In this specification, a structure in which two substrates are connected will be described as an example, but three or more substrates may be connected. The first wiring 2 is not limited to the arrangement shown in FIG. 1 , and the extension direction is also not limited. Specifically, the longitudinal direction of the first substrate 1 and the extension direction of the first wiring 2 do not have to coincide, and the first wiring 2 does not have to extend in one direction. The number of first wirings 2 is not particularly limited, and may be one or more. When there are multiple first wirings 2, they may include wirings that are not electrically connected to the second wiring 4. The same applies to the arrangement and number of second wirings 4.

[0014] Furthermore, "above" in this specification does not have to coincide with the up and down when the stretchable device 100 is in use. More specifically, "on the main surface of the first substrate 1" does not refer to an absolute direction such as vertically upward, which is determined by the direction of gravity, but rather refers to the direction toward the outside of the inside and outside that are bounded by the main surface of the first substrate 1. The same applies to "on the main surface of the second substrate 3." Furthermore, "above" with respect to a certain element does not only refer to an upper side away from the element, i.e., an upper position above the element via another object or an upper position above that is spaced apart, but also includes a position directly above that element (on).

[0015] These components and their arrangement will be described below. As shown in Figures 1, 2, and 3, the first substrate 1 and the second substrate 3 face each other in the first direction X and partially overlap each other when viewed from the first direction X. Similarly, the first wiring 2 and the second wiring 4 face each other in the first direction X.

[0016] The first base material 1 has stretchability. When the first base material 1 has stretchability, it does not inhibit the stretching of the first wiring 2, and it is possible to reduce the risk of breakage due to stretching when the stretchable device 100 is in use.

[0017] Examples of stretchable substrates include sheet- or film-shaped substrates made of stretchable resin materials. The resin material preferably contains at least one resin selected from the group consisting of acrylic resins, styrene resins, and urethane resins. Examples of urethane resins include thermoplastic polyurethanes. The thickness of the first substrate 1 is not particularly limited, but is preferably 1 mm or less, more preferably 100 μm or less, and even 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 first substrate 1 is more preferably 1 μm or more.

[0018] The first substrate 1 has a first main surface 1a and a second main surface 1b located opposite each other. The first substrate 1 has a first substrate end portion 11 connecting the first main surface 1a and the second main surface 1b. The first substrate end portion 11 is the end portion of the first substrate 1 that is closer to the second substrate 3, in other words, the end portion that overlaps with the second wiring 4 when viewed from the first direction X. Specifically, of both ends in the up-down direction in FIG. 1, it is the end portion that is closer to the second substrate 3, and of both ends in the left-right direction in FIG. 3, it is the end portion that is closer to the second substrate 3. Note that ends other than the first substrate end portion 11 are not shown in FIGS. 1, 2, and 3.

[0019] The first wiring 2 is provided on the first main surface 1a of the first substrate 1. The first wiring 2 is preferably stretchable. Examples of materials for the first wiring 2 include a mixture of conductive particles, such as metal powder of Ag, Cu, and / 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. The conductive particles are preferably spherical, but may be flat or have protrusions to improve stretchability. The elastomer resin preferably contains at least one resin (elastomer resin) selected from the group consisting of epoxy resins, urethane resins, acrylic resins, and silicone resins, which is preferable for ensuring stretchability.

[0020] The thickness of the first wiring 2 is preferably 100 μm or less, more preferably 50 μm or less. The thickness of the stretchable wiring is more preferably 1 μm or more. The thickness, width, and length of the first wiring are not particularly limited. The first wiring 2 does not have to be stretchable.

[0021] A method for forming the first wiring 2 on the first substrate 1 will be described. When the material of the first wiring 2 is, for example, a conductive paste containing a mixture of Ag and resin, the conductive paste is applied to the first substrate 1. The application method may be screen printing, gravure printing, or inkjet printing. The conductive paste is then thermally cured to obtain a predetermined resistance value, thereby forming the first wiring 2 on the first substrate 1.

[0022] The second substrate 3 is preferably elastic. The second substrate 3 preferably has a larger Young's modulus than the first wiring 2. Specific examples include substrates such as FPC (Flexible Printed Circuit), FFC (Flexible Flat Cable), and PCB (Printed Circuit Board). By making the Young's modulus larger than that of the first wiring 2, pressure can be more easily applied to the joint during crimping, enabling bonding with low pressure. In other words, lowering the pressure can reduce damage to the substrates during bonding. Furthermore, the second substrate 3 preferably has a larger Young's modulus than the first substrate 1. This makes the second substrate 3 more resistant to impacts during connection, thereby further improving connection reliability.

[0023] The second substrate 3 has a first main surface 3a and a second main surface 3b located opposite each other. The second substrate 3 has a second substrate end portion 31 connecting the first main surface 3a and the second main surface 3b. The second substrate end portion 31 is the end portion of the second substrate 3 that is closer to the first substrate 1, in other words, the end portion that overlaps with the first wiring 2 when viewed from the first direction X. Specifically, of both ends in the up-down direction in FIG. 1, it is the end portion that is closer to the first substrate 1, and of both ends in the left-right direction in FIG. 3, it is the end portion that is closer to the first substrate 1. Note that ends other than the second substrate end portion 31 are not shown in FIGS. 1, 2, and 3.

[0024] The second substrate 3 is connected to the first substrate 1. That is, the first main surface 1a of the first substrate 1 and the first main surface 3a of the second substrate 3 are directly connected by welding or the like. Specifically, the first main surface 1a of the first substrate 1 and the first main surface 3a of the second substrate 3 are thermocompression bonded. Note that the first substrate 1 and the second substrate 3 may be connected via an adhesive member such as a thermoplastic adhesive, for example.

[0025] The second base material 3 does not have to be stretchable. Examples of materials for the second base material 3 include sheet- or film-shaped substrates such as PET and polyimide, and substrates such as FPC, FFC, and PCB. The material for the second base material 3 may be the same as the material for the first base material 1.

[0026] The second wiring 4 is provided on the first main surface 3a of the second substrate 3. The second wiring 4 is preferably stretchable. The second wiring 4 is preferably a wiring having a larger Young's modulus than the first wiring 2. For example, a metal wiring such as copper foil can be used. The thickness of the second wiring 4 is preferably 1 μm or more and 100 μm or less, more preferably 50 μm or less. The first wiring 2 and the second wiring 4 are in direct contact with each other and electrically connected. The second wiring 4 does not have to be stretchable. The material of the second wiring 4 may be the same as the material of the first wiring 2.

[0027] The second wiring 4 is electrically connected to the first wiring 2. Specifically, the first wiring 2 and the second wiring 4 are in contact with each other and electrically connected. When viewed from the first direction X, the region where the first wiring 2 and the second wiring 4 overlap constitutes a wiring region Z0 where the first wiring 2 and the second wiring 4 are electrically connected. The first wiring 2 and the second wiring 4 may be electrically connected via a conductive connecting member. In this case, when viewed from the first direction X, the region where the first wiring 2 and the second wiring 4 overlap and the region where the connecting member exists constitute a wiring region Z0 where the first wiring 2 and the second wiring 4 are electrically connected.

[0028] The first protective layer 6 is provided on the first main surface 1a of the first substrate 1 so as to cover a portion of the first wiring 2. In this way, the first protective layer 6 covers a portion of the first wiring 2, and therefore, even if water droplets or foreign matter adhere across the gap between adjacent first wirings 2, it is possible to prevent short circuits between adjacent first wirings 2, and also to reduce exposure of the first wirings 2 to air and moisture, thereby preventing oxidation and corrosion of the first wirings 2. The first protective layer 6 may be provided so as to cover all of the first wirings 2 as a whole, or the first protective layer 6 may be provided in sections so as to cover each of the first wirings 2 individually.

[0029] Specifically, the first protective layer 6 covers a portion of the first wiring 2, is in contact with the first main surface 1a of the first base material 1, and overlaps with the first base material 1 when viewed from the first direction X. Preferably, the first protective layer 6 is in contact with a portion of the region of the first base material 1 that is exposed from the first wiring 2. Note that the first protective layer 6 does not have to cover the first wiring 2 and not be in contact with the first base material 1.

[0030] Specific examples of the first protective layer 6 include resin materials or mixtures of resin materials and inorganic materials. Examples of resin materials include urethane-based, styrene-based, olefin-based, silicone-based, fluorine-based, nitrile rubber, latex rubber, vinyl chloride, ester-based, and amide-based elastomer resins, as well as epoxy, phenolic, acrylic, polyester, imide-based, rosin, cellulose, polyethylene terephthalate-based, polyethylene naphthalate-based, and polycarbonate-based resins. The first protective layer 6 is preferably insulating. Having insulating properties in the first protective layer 6 can more reliably suppress ion migration in the first wiring 6. The first protective layer 6 is formed, for example, by applying an insulating material or attaching a laminate material.

[0031] The thickness of the first protective layer 6 is preferably 1 μm or more and 100 μm or less, and more preferably 50 μm or less. By making the thickness of the first protective layer 6 1 μm or more, the durability of the first protective layer 6 can be ensured. Furthermore, by making the thickness of the first protective layer 6 100 μm or less, the overall height can be reduced. Note that when the thickness of the first protective layer 6 is not constant, the maximum dimension of the first protective layer 6 in the first direction X is taken as the thickness.

[0032] The first protective layer 6 also has a first protective layer end 61. The first protective layer end 61 is the end of the first protective layer 6 that is closer to the first substrate end 11, specifically, of both ends in the up-down direction in Fig. 1, it is the end that is closer to the first substrate end 11, and of both ends in the left-right direction in Fig. 3, it is the end that is closer to the first substrate end 11. Note that ends different from the first protective layer end 61 are not shown in Figs. 1, 2, and 3.

[0033] When viewed from the first direction X, a first overlapping region Z11 where the first base material 1 and the first protective layer 6 overlap is separated from a wiring region Z0 where the first wiring 2 and the second wiring 4 are electrically connected. Specifically, when viewed from the first direction X, the first protective layer end 61 and the end of the second wiring 4 are separated. When viewed from the first direction X, the wiring region Z0 and the first overlapping region Z11 are separated in the extension direction of the first wiring 2. In this embodiment, the extension direction of the first wiring 2 and the extension direction of the second wiring 4 coincide with each other.

[0034] According to the above configuration, the first overlapping region Z11 is separated from the wiring region Z0 as viewed from the first direction X, and therefore a first non-overlapping region Z12 that does not overlap with the first protective layer 6 of the first base material 1 exists between the first overlapping region Z11 and the wiring region Z0 as viewed from the first direction X. In other words, the first non-overlapping region Z12 exists between the first protective layer end 61 and the end of the second wiring 4 as viewed from the first direction X.

[0035] This makes it possible to alleviate the stress applied to the stretchable device 100 in the first non-overlapping region Z12 when stretching the stretchable device 100. Therefore, it is possible to reduce damage to the stretchable device 100, such as breakage of the first wiring 2, and also to suppress deterioration in the performance of the stretchable device 100, such as an increase in the resistance value of the first wiring 2.

[0036] In short, in the wiring region Z0, the first wiring 2, the second wiring 4, the first substrate 1, and the second substrate 3 overlap, so the stretchability of the first substrate 1 decreases, and this becomes a portion with high rigidity in the stretchable device 100. Furthermore, in the first overlapping region Z11, the first substrate 1, the first wiring 2, and the first protective layer 6 overlap, so the stretchability of the first substrate 1 decreases, and this becomes a portion with high rigidity in the stretchable device 100. On the other hand, in the first non-overlapping region Z12, the first substrate 1 is not covered with the first protective layer 6, so the stretchability of the first substrate 1 can be ensured, and this becomes a portion with stretchability in the stretchable device 100. Therefore, when the stretchable device 100 stretches or shrinks, the stress applied to the portion with high rigidity can be absorbed by the first non-overlapping region Z12.

[0037] That is, the inventors of the present application have noticed that when the stretchable device 100 is stretched or contracted, stress is concentrated locally in portions with high rigidity. Furthermore, the inventors of the present application have noticed that the rigidity of the wiring region Z0 and the rigidity of the first overlapping region Z11 are different because the number of layers in the wiring region Z0 (four layers: the first wiring 2, the second wiring 4, the first substrate 1, and the second substrate 3) is different from the number of layers in the first overlapping region Z11 (three layers: the first substrate 1, the first wiring 2, and the first protective layer 6). The inventors of the present application have then found that when the wiring region Z0 and the first overlapping region Z11 are adjacent to each other when viewed from the first direction X, as in the conventional case, stress is concentrated between the wiring region Z0 and the first overlapping region Z11. From this perspective, the inventors of the present application have realized a stretchable device 100 that can relieve stress by making the area where this stress concentrates (i.e., between the wiring area Z0 and the first overlapping area Z11) into a stretchable area (i.e., the first non-overlapping area Z12).

[0038] Preferably, the shortest distance between the first overlap region Z11 and the wiring region Z0, as viewed from the first direction X, is 1 μm or more and 30 mm or less, more preferably 1 μm or more and 10 mm or less. That is, as viewed from the first direction X, the shortest distance between the first protective layer end 61 and the second substrate end 31 in the extension direction of the first wiring 2 is 1 μm or more and 30 mm or less. Therefore, because the shortest distance is 1 μm or more, the expansion and contraction performance of the first substrate 1 can be improved in the first non-overlapping region Z12, and stress relaxation can be improved in the first non-overlapping region Z12. Furthermore, because the shortest distance is 30 mm or less, the expansion and contraction performance of the first substrate 1 can be sufficiently ensured in the first non-overlapping region Z12, and exposure of the first wiring 2 can be reduced, thereby reducing short circuits between adjacent first wirings 2.

[0039] Next, the connection in the stretchable device 100 will be described. When connecting the first substrate 1 and the second substrate 3, the first substrate 1 and the second substrate 3 are thermocompression-bonded by applying heat and pressure. This connects the first substrate 1 and the second substrate 3. There is no particular limitation on the method for compressing the first substrate 1 and the second substrate 3. Furthermore, the first wiring 2 and the second wiring 4 come into contact with each other and are electrically connected.

[0040] [Second embodiment] Next, a second embodiment will be described with reference to Fig. 4. Fig. 4 is a partial cross-sectional view of a stretchable device 101 according to the second embodiment. The stretchable device 101 according to the second embodiment differs from the stretchable device 100 according to the first embodiment in that a second protective layer is provided.

[0041] 4, the stretchable device 101 of the second embodiment further includes a second protective layer 7. The material and thickness of the second protective layer 7 are the same as the material and thickness of the first protective layer 6, but the thickness may be different, and similarly the material may be different.

[0042] The second protective layer 7 is provided on the first main surface 3a of the second base material 3 so as to cover a portion of the second wiring 4. In this way, the second protective layer 7 covers a portion of the second wiring 4, and therefore, even if water droplets or foreign matter adhere across the gap between adjacent second wirings 4, it is possible to suppress short-circuiting between the adjacent second wirings 4, and also to reduce exposure of the second wirings 4 to air and moisture, thereby suppressing the occurrence of oxidation and corrosion of the second wirings 4.

[0043] Specifically, the second protective layer 7 covers a portion of the second wiring 4, is in contact with the first main surface 3a of the second base material 3, and overlaps with the second base material 3 when viewed from the first direction X. Preferably, the second protective layer 7 is in contact with a portion of the region of the second base material 3 that is exposed from the second wiring 4. Note that the second protective layer 7 does not have to cover the second wiring 4 and not be in contact with the second base material 3.

[0044] The second protective layer 7 has a second protective layer end portion 71. The second protective layer end portion 71 is the end portion of the second protective layer 7 that is closer to the second substrate end portion 31, specifically, of both ends in the left-right direction in Fig. 4, it is the end portion that is closer to the second substrate end portion 31. Note that in Fig. 4, ends different from the second protective layer end portion 71 are not shown.

[0045] When viewed from the first direction X, a second overlapping region Z21 where the second base material 3 and the second protective layer 7 overlap is separated from the wiring region Z0. Specifically, when viewed from the first direction X, the second protective layer end 71 and the first base material end 11 are separated from each other. When viewed from the first direction X, the wiring region Z0 and the second overlapping region Z21 are separated from each other in the extension direction of the second wiring 4. In this embodiment, the extension direction of the first wiring 2 and the extension direction of the second wiring 4 coincide with each other.

[0046] According to the above configuration, the second overlapping region Z21 is separated from the wiring region Z0 as viewed from the first direction X, and therefore a second non-overlapping region Z22 that does not overlap with the second protective layer 7 of the second base material 3 exists between the second overlapping region Z21 and the wiring region Z0 as viewed from the first direction X. In other words, the second non-overlapping region Z22 exists between the second protective layer end 71 and the first base material end 11 as viewed from the first direction X.

[0047] This makes it possible to alleviate the stress applied to the stretchable device 101 in the second non-overlapping region Z22 when stretching the stretchable device 101. In particular, when the second base material 3 is stretchable, it is possible to reduce damage to the stretchable device 101, such as breakage of the second wiring 4, and also to suppress deterioration in the performance of the stretchable device 101, such as an increase in the resistance value of the second wiring 4.

[0048] [Third embodiment] Next, a third embodiment will be described with reference to Fig. 5. Fig. 5 is a partial cross-sectional view of a stretchable device 102 according to the third embodiment. The stretchable device 102 according to the third embodiment differs from the stretchable device 101 according to the second embodiment in that a third protective layer and a fourth protective layer are provided.

[0049] 5, the stretchable device 102 of the third embodiment further includes a third protective layer 8 and a fourth protective layer 9. The material and thickness of the third protective layer 8 and the fourth protective layer 9 are the same as the material and thickness of the first protective layer 6, but the thickness may be different, and similarly the material may be different.

[0050] The third protective layer 8 is provided on the second main surface 1b of the first base material 1. The third protective layer 8 preferably covers the entire second main surface 1b of the first base material 1, but it is sufficient if it covers at least a part of the second main surface 1b of the first base material 1. According to the above configuration, the third protective layer 8 improves the waterproof performance of the first base material 1. Furthermore, using a biocompatible material for the third protective layer 8 improves biocompatibility.

[0051] The fourth protective layer 9 is provided on the second main surface 3b of the second base material 3. The fourth protective layer 9 preferably covers the entire second main surface 3b of the second base material 3, but may cover only a portion of the second main surface 3b of the second base material 3. According to the above configuration, the fourth protective layer 9 improves the waterproof performance of the second base material 3. Furthermore, using a biocompatible material for the fourth protective layer 9 improves biocompatibility.

[0052] It is also possible to provide only one of the third protective layer 8 and the fourth protective layer 9. Furthermore, it is also possible to provide at least one of the third protective layer 8 and the fourth protective layer 9 to the stretchable device 100 according to the first embodiment.

[0053] [Fourth embodiment] Next, a fourth embodiment will be described with reference to Fig. 6. Fig. 6 is a partial cross-sectional view of a stretchable device 103 according to the fourth embodiment. The stretchable device 103 according to the fourth embodiment differs from the stretchable device 100 according to the first embodiment in that a first insulating layer and a second insulating layer are provided.

[0054] 6, the stretchable device 103 of the fourth embodiment further includes a first insulating layer 21 and a second insulating layer 22. The materials of the first insulating layer 21 and the second insulating layer 22 are different from the material of the first protective layer 6.

[0055] The first insulating layer 21 and the second insulating layer 22 preferably have a lower water absorption rate than the first substrate 1. Examples of materials for the first insulating layer 21 and the second insulating layer 22 include silicone resins, acrylic resins, olefin resins, modified urethane resins, vinyl chloride resins, polyesters, polyamides, polyolefins, polyethylenes, and polypropylenes. The first insulating layer 21 and the second insulating layer 22 are formed by, for example, printing.

[0056] The first insulating layer 21 covers at least a portion of the exposed surface of the first wiring 2. The exposed surface of the first wiring 2 is the surface of the outer surface of the first wiring 2 that is exposed to the outside. Specifically, the exposed surface of the first wiring 2 is the surface of the first wiring 2 that is not covered by the first substrate 1, the first protective layer 6, and the second wiring 4. The first insulating layer 21 preferably covers the entire exposed surface of the first wiring 2, but may cover a portion of the exposed surface of the first wiring 2. The first insulating layer 21 is also preferably present between the first wiring 2 and the first protective layer 6. The first insulating layer 21 does not overlap the second wiring 4 in the first direction X, but a portion of the first insulating layer 21 may overlap the second wiring 4 in the first direction X. According to the above configuration, the first insulating layer 21 prevents short-circuiting between adjacent first wirings 2 due to water droplets or foreign matter, thereby improving reliability.

[0057] Here, the method for forming the first insulating layer 21 will be described. An insulating paste, which is the material for the first insulating layer 21, is printed on the first wiring 2 by screen printing or the like. At this time, in a cross section perpendicular to the extension direction of the first wiring 2, the insulating paste is preferably printed to a size larger than the width of the first wiring 2 by 1 μm to 10 mm, more preferably by 20 μm to 1000 μm.

[0058] The second insulating layer 22 covers at least a portion of the exposed surface of the second wiring 4. The exposed surface of the second wiring 4 is the surface of the outer surface of the second wiring 4 that is exposed to the outside. Specifically, the exposed surface of the second wiring 4 is the surface of the second wiring 4 that is not covered by the second substrate 3 and the first wiring 2. The second insulating layer 22 preferably covers the entire exposed surface of the second wiring 4, but may cover a portion of the exposed surface of the second wiring 4. Furthermore, the second insulating layer 22 does not overlap the first wiring 2 in the first direction X, but a portion of the second insulating layer 22 may overlap the first wiring 2 in the first direction X. According to the above configuration, the second insulating layer 22 prevents short-circuiting between adjacent second wirings 4 due to water droplets or foreign matter, thereby improving reliability.

[0059] It is also possible to provide only one of the first insulating layer 21 and the second insulating layer 22. Furthermore, at least one of the first insulating layer 21 and the second insulating layer 22 may be provided for the stretchable devices 101, 102 according to the second and third embodiments.

[0060] [Fifth embodiment] Next, a fifth embodiment will be described with reference to Fig. 7. Fig. 7 is a partial cross-sectional view of a stretchable device 104 according to the fifth embodiment. The stretchable device 104 according to the fifth embodiment differs from the stretchable device 103 according to the fourth embodiment in that a third insulating layer and a fourth insulating layer are provided.

[0061] 7, the stretchable device 104 of the fifth embodiment further includes a third insulating layer 23 and a fourth insulating layer 24. The materials of the third insulating layer 23 and the fourth insulating layer 24 may be the same as the materials of the first insulating layer 21 and the second insulating layer 22, or may be different materials.

[0062] The third insulating layer 23 is disposed between the first wiring 2 and the first base material 1 in the first direction X. In other words, the third insulating layer 23 is provided on the first main surface 1a of the first base material 1, and is in contact with the lower surface of the first wiring 2 (i.e., the surface of the first wiring 2 facing the first main surface 1a of the first base material 1).

[0063] If the first substrate 1 is moisture permeable, moisture may penetrate from the first substrate 1 into the first wiring 2, causing ion migration. By providing the third insulating layer 23, it is possible to prevent moisture from penetrating from the first substrate 1 into the first wiring 2. In other words, a stretchable device 104 is provided in which short-circuiting of the first wiring 2 is prevented.

[0064] The fourth insulating layer 24 is disposed between the second wiring 4 and the second base material 3 in the first direction X. In other words, the fourth insulating layer 24 is provided on the first main surface 3a of the second base material 3, and is in contact with the lower surface of the second wiring 4 (i.e., the surface of the second wiring 4 facing the first main surface 3a of the second base material 3).

[0065] If the second base material 3 is moisture permeable, moisture may penetrate from the second base material 3 into the second wiring 4, causing ion migration. By providing the fourth insulating layer 24, it is possible to prevent moisture from penetrating from the second base material 3 into the second wiring 4. In other words, a stretchable device 104 is provided in which short-circuiting of the second wiring 4 is prevented.

[0066] It is also possible to provide only one of the third insulating layer 23 and the fourth insulating layer 24. Furthermore, at least one of the third insulating layer 23 and the fourth insulating layer 24 may be provided for the stretchable devices 100, 101, 102 according to the first, second, and third embodiments.

[0067] Furthermore, the third insulating layer 23 may be disposed so as to cover only the lower surface of the first wiring 2, or may be disposed in a portion of the first substrate 1 where the first wiring 2 is not present. The third insulating layer 23 may be disposed so as to cover the entire first substrate 1. The third insulating layer 23 only needs to be in contact with the second wiring 2, and a different layer may be disposed between the first substrate 1 and the third insulating layer 23. The fourth insulating layer 24 may also be the same as the third insulating layer 23.

[0068] [Sixth embodiment] Next, a sixth embodiment will be described with reference to Fig. 8. Fig. 8 is a partial cross-sectional view of a stretchable device 105 according to the sixth embodiment. The stretchable device 105 according to the sixth embodiment differs from the stretchable device 103 according to the fourth embodiment in that a first covering layer and a second covering layer are provided.

[0069] 8, the stretchable device 105 of the sixth embodiment further includes a first covering layer 41 and a second covering layer 42. The materials of the first covering layer 41 and the second covering layer 42 are different from the material of the first protective layer 6.

[0070] The first covering layer 41 covers at least the end of the second substrate 3 on the first substrate side. With this structure, the second substrate 3 can be protected from external forces. More preferably, the first covering layer 41 covers the first main surface 1a side of the first substrate 1. Specifically, the first covering layer 41 covers at least a portion of the first main surface 1a of the first substrate 1, at least a portion of the first insulating layer 21, at least a portion of the first protective layer 6, and at least a portion of the second main surface 3b of the second substrate 3. With this structure, the first protective layer 6 and the portion of the first wiring 2 exposed from the first protective layer 6 can be protected from external forces.

[0071] An example of the first covering layer 41 is a resin material. For example, the first covering layer 41 is preferably a flexible resin. Specifically, the first covering layer 41 may be formed of an ionomer resin, a polyester resin, a styrene resin, an olefin resin, an epoxy resin, a urethane resin, an acrylic resin, or a silicone resin, and is preferably formed of a silicone resin. The first covering layer 41 may also be a thermoplastic resin. Specifically, examples of the first covering layer 41 include thermoplastic polyurethane (TPU) and styrene-butadiene-styrene copolymer resin (SBS). The first covering layer 41 may be composed of multiple components. Using a resin for the first covering layer 41 can more effectively protect the connection portion from external forces.

[0072] The second covering layer 42 covers at least the end of the first substrate 1 facing the second substrate. This structure protects the first substrate 1 from external forces. More preferably, the second covering layer 42 covers the first main surface 3a side of the second substrate 3. Specifically, the second covering layer 42 covers at least a portion of the first main surface 3a of the second substrate 3, at least a portion of the second insulating layer 22, and at least a portion of the second main surface 1b of the first substrate 1. This configuration protects the second insulating layer 22 and the portion of the second wiring 4 exposed from the second insulating layer 22 from external forces.

[0073] An example of the second covering layer 42 is a resin material. For example, the first covering layer 41 is preferably a flexible resin. Specifically, the first covering layer 41 may be formed of an ionomer resin, a polyester resin, a styrene resin, an olefin resin, an epoxy resin, a urethane resin, an acrylic resin, or a silicone resin, and is preferably formed of a silicone resin. The second covering layer 42 may also be a thermoplastic resin. Specifically, examples of the thermoplastic resin include thermoplastic polyurethane (TPU) and styrene-butadiene-styrene copolymer resin (SBS) as a styrene resin. The second covering layer 42 may be composed of multiple components. Using a resin for the second covering layer 42 can more effectively protect the connection portion from external forces. The first covering layer 41 and the second covering layer 42 may be the same component or different components.

[0074] Resin-containing members such as the first protective layer 6, the first insulating layer 21, and the second insulating layer 22 may be cytotoxic. By providing the first covering layer 41, it is possible to suppress leakage of cytotoxic components. The same effect can be achieved with the second covering layer 42. Furthermore, by providing the first covering layer 41 and the second covering layer 42, it is possible to further suppress leakage of cytotoxic components.

[0075] Furthermore, the first covering layer 41 continuously covers the second main surface 3b of the second base material 3, the first insulating layer 21, and the first protective layer 6. In other words, the first covering layer 41 continuously covers the wiring region Z0, the first non-overlapping region Z12, and the first overlapping region Z11. As a result, the first covering layer 41 covers the first non-overlapping region Z12, which forms a recess with respect to the wiring region Z0 and the first overlapping region Z11, and therefore a stretchable device 105 that can reduce the recess can be provided. Therefore, a stretchable device 105 with improved wearability can be provided.

[0076] Furthermore, the first covering layer 41 overlaps the first protective layer 6 when viewed from the first direction X. As a result, the first covering layer 41 is disposed on the first protective layer 6, and therefore the step between the first main surface 1a side of the first base material 1 and the second main surface 3b side of the second base material 3 is reduced by the thickness of the first protective layer 6.

[0077] Furthermore, the second coating layer 42 continuously covers the first main surface 3a side of the second substrate 3 and the second main surface 1b side of the first substrate 1. This makes it possible to prevent damage to the first main surface 3a side of the second substrate 3 and the second main surface 1b side of the first substrate 1.

[0078] It is also possible to provide only one of the first covering layer 41 and the second covering layer 42. Furthermore, at least one of the first covering layer 41 and the second covering layer 42 may be provided on the stretchable devices 100, 101, 102, and 104 according to the first, second, third, and fifth embodiments.

[0079] [Seventh embodiment] Next, a seventh embodiment will be described with reference to Fig. 9. Fig. 9 is a partial cross-sectional view of a stretchable device 106 according to the seventh embodiment. The stretchable device 106 according to the seventh embodiment differs from the stretchable device 100 according to the first embodiment in that a connecting member is provided.

[0080] As shown in Fig. 9, the stretchable device 106 of the seventh embodiment further includes a connection member 5. In Fig. 9, the connection member 5 is shown by hatching with dots for convenience. The connection member 5 electrically connects the first wiring 2 and the second wiring 4. In this case, when viewed from the first direction X, the region where the first wiring 2 and the second wiring 4 overlap and the region where the connection member 5 exists constitute a wiring region Z0 where the first wiring 2 and the second wiring 4 are electrically connected.

[0081] A portion of the connection member 5 is located between the first wiring 2 and the second wiring 4. A portion of the connection member 5 is located outside the end of the first wiring 2 so as to cover the end of the first wiring 2 in the extension direction. A portion of the connection member 5 is located outside the end of the second wiring 4 so as to cover the end of the second wiring 4 in the extension direction. Examples of the connection member 5 include ACF (Anisotropic Conductive Film), conductive paste, and solder. The connection member 5 preferably contains resin and conductive particles. The conductive particles contained in the connection member 5 come into contact with the first wiring 2 and the second wiring 4, thereby electrically connecting the first wiring 2 and the second wiring 4.

[0082] Furthermore, the connection member 5 connects the first wiring 2 and the second wiring 4. The connection member 5 also contacts the first main surface 1a of the first substrate 1 and the first main surface 3a of the second substrate 3, connecting the first substrate 1 and the second substrate 3.

[0083] Next, the connection of the stretchable device 106 will be described. When connecting the first substrate 1 and the second substrate 3, the first substrate 1 and the second substrate 3 may be pressure-bonded, such as by applying pressure. By performing such a process, the connection member 5 deforms, changing the overall thickness. In other words, a low profile of the stretchable device 106 can be achieved. Furthermore, as described above, when the connection member 5 containing conductive particles is provided between the first wiring 2 and the second wiring 4, electrical continuity cannot be achieved if the distance between the first wiring 2 and the second wiring 4 in the first direction X is greater than the maximum diameter of the conductive particles. In such a case, pressure-bonding as described above reduces the distance between the first wiring 2 and the second wiring 4 in the first direction X. Therefore, the electrical connection between the first wiring 2 and the second wiring 4 can be more reliably achieved.

[0084] Note that if the first wiring 2 and the second wiring 4 are electrically connected before the pressure-bonding, the pressure-bonding does not have to be performed. Also, if the connection member 5 has adhesiveness, the pressure-bonding does not have to be performed. Also, the pressure-bonding method is not particularly limited.

[0085] [Eighth embodiment] Next, an eighth embodiment will be described with reference to Fig. 10. Fig. 10 is a partial cross-sectional view of a stretchable device 107 according to the eighth embodiment. The stretchable device 107 according to the eighth embodiment differs from the stretchable device 106 according to the seventh embodiment in the length of the second base material.

[0086] 10 , in a stretchable device 107 of the eighth embodiment, the second substrate 3 extends in the first direction X to a position where it overlaps with the first protective layer 6. Specifically, a second substrate end 31 of the second substrate 3 overlaps with the first protective layer 6 when viewed from a direction perpendicular to the first direction X. In other words, the second substrate 3 overlaps with the first non-overlapping region Z12. This allows the second substrate 3 to protect the exposed portion of the first wiring 2 located in the first non-overlapping region Z12.

[0087] The present disclosure is not limited to the above-described embodiments, and design modifications are possible without departing from the spirit of the present disclosure. For example, the features of the first to eighth embodiments may be combined in various ways.

[0088] The present disclosure includes the following aspects. <1> a first base material having elasticity; a first wiring provided on a first main surface of the first base material; a second base material that faces the first base material in a first direction that is a thickness direction of the first base material and is connected to the first base material; a first wiring layer provided on a first main surface of the second base material and facing the first wiring in the first direction; a second wiring electrically connected to the first wiring; a first protective layer provided on the first main surface of the first base material so as to cover a portion of the first wiring; Equipped with A stretchable device, wherein a first overlap region where the first substrate and the first protective layer overlap when viewed from the first direction is separated from a wiring region where the first wiring and the second wiring are electrically connected. <2> Further, a second protective layer is provided on the first main surface of the second base material, a second overlapping region where the second base material and the second protective layer overlap each other as viewed from the first direction, the second overlapping region being spaced apart from the wiring region; <1> 2. The stretchable device according to claim 1 . <3> Further, a third protective layer is provided on the second main surface of the first base material. <1> or <2> 2. The stretchable device according to claim 1 . <4> Further, a fourth protective layer is provided on the second main surface of the second base material. <1> from <3> 1. The stretchable device according to any one of the above. <5> Further, a first insulating layer is provided to cover at least a part of the exposed surface of the first wiring. <1> from <4> 1. The stretchable device according to any one of the above. <6> Further, a second insulating layer is provided to cover at least a part of the exposed surface of the second wiring. <1> from <5> 1. The stretchable device according to any one of the above. <7> Further, a third insulating layer is provided between the first wiring and the first base material. <1> from <6> 1. The stretchable device according to any one of the above. <8> Further, a fourth insulating layer is provided between the second wiring and the second base material. <1> from <7> 1. The stretchable device according to any one of the above. <9> Further, a first coating layer is provided to cover the first main surface side of the first base material. <1> from <8> 1. The stretchable device according to any one of the above. <10> the first coating layer overlaps the first protective layer when viewed from the first direction; <9> 2. The stretchable device according to claim 1 . <11> Further, a second coating layer is provided to cover the first main surface side of the second base material. <1> from <10> 1. The stretchable device according to any one of the above. <12> the second coating layer continuously covers the first main surface side of the second base material and the second main surface side of the first base material; <11> 2. The stretchable device according to claim 1 . [Explanation of symbols]

[0089] 100, 101, 102, 103, 104, 105, 106, 107 Stretchable devices 1 First base material 1a First principal surface 1b Second principal surface 11 First base material end 2 1st wiring 3 Second base material 3a 1st principal surface 3b 2nd principal surface 31 Second base material end 4 2nd wiring 5. Connecting members 6 1st protective layer 61 1st protective layer end 7 Second protective layer 71 Second protective layer end 8 Third protective layer 9 Fourth protective layer 21 First insulating layer 22 Second insulating layer 23 Third insulating layer 24 Fourth insulating layer 41 1st coating layer 42 Second coating layer X 1st direction Z0 wiring area Z11 1st overlap area Z12 1st non-overlapping area Z21 2nd overlap area Z22 2nd non-overlapping area

Claims

1. a first base material having elasticity; a first wiring provided on a first main surface of the first base material; a second substrate facing the first substrate in a first direction that is a thickness direction of the first substrate and connected to the first substrate; a second wiring provided on a first main surface of the second base material, facing the first wiring in the first direction, and electrically connected to the first wiring; a first protective layer provided on the first main surface of the first base material so as to cover a portion of the first wiring; Equipped with a first overlapping region where the first base material and the first protective layer overlap each other as viewed from the first direction is separated from a wiring region where the first wiring and the second wiring are electrically connected; the first wiring and the second wiring are electrically connected to each other by contact or via a connection member, When the first wiring and the second wiring are electrically connected via the connection member, the wiring region includes a region where the first wiring and the second wiring overlap and a region where the connection member is present. A stretchable device.

2. Further, a second protective layer is provided on the first main surface of the second base material, The stretchable device according to claim 1 , wherein a second overlap region in which the second base material and the second protective layer overlap when viewed from the first direction is separated from the wiring region.

3. The stretchable device according to claim 1 or 2, further comprising a third protective layer provided on the second main surface of the first substrate.

4. The stretchable device according to claim 1 , further comprising a fourth protective layer provided on the second main surface of the second substrate.

5. The stretchable device according to claim 1 , further comprising a first insulating layer covering at least a portion of the exposed surface of the first wiring.

6. The stretchable device according to claim 1 , further comprising a second insulating layer covering at least a portion of the exposed surface of the second wiring.

7. The stretchable device according to claim 1 , further comprising a third insulating layer between the first wiring and the first substrate.

8. The stretchable device according to claim 1 , further comprising a fourth insulating layer between the second wiring and the second substrate.

9. The stretchable device according to claim 1 , further comprising a first covering layer covering the first main surface side of the first substrate.

10. The stretchable device of claim 9 , wherein the first covering layer overlaps the first protective layer when viewed from the first direction.

11. The stretchable device according to claim 1 , further comprising a second covering layer covering the first main surface side of the second substrate.

12. The stretchable device according to claim 11 , wherein the second covering layer continuously covers a first main surface side of the second substrate and a second main surface side of the first substrate.

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