Stretchable device
By integrating a reinforcing member in the overlapping region of the substrates, the stretchable device addresses bonding strength issues, enhancing reliability through improved stress resistance.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MURATA MFG CO LTD
- Filing Date
- 2025-11-19
- Publication Date
- 2026-07-23
AI Technical Summary
Existing stretchable devices face challenges in maintaining sufficient bonding strength between the first and second wirings due to stress applied during stretching or contraction, leading to potential delamination and peeling.
Incorporating a reinforcing member in the overlapping region of the first and second substrates, with a length in the second direction longer than the substrates, to enhance bonding strength and prevent delamination.
The reinforcing member effectively prevents peeling and delamination between the first and second wirings, improving the overall bonding strength and reliability of the stretchable device.
Smart Images
Figure JP2025040355_23072026_PF_FP_ABST
Abstract
Description
Stretchable device
[0006] ,
[0001] This disclosure relates to stretchable devices.
[0002] Patent Document 1 and Patent Document 2 disclose a stretchable device including a first base material, a first wiring provided on the first base material and having stretchability, a second base material facing the first base material in the thickness direction of the first base material, and a second wiring provided on the second base material and facing the first wiring in the thickness direction, and further including a connection member for electrically connecting the first wiring and the second wiring.
[0003] International Publication No. 2023 / 171464, International Publication No. 2023 / 171294
[0004] Patent Document 1 and Patent Document 2 disclose preventing the occurrence of migration. On the other hand, the inventor of the present application focused on increasing the bonding strength between the first wiring and the second wiring. The point of increasing the bonding strength will be described in detail while referring to FIGS. 1A, 1B, and 2.
[0005] FIGS. 1A and 1B show a stretchable device 1z including a first base material 100, a first wiring 110 provided on the first base material 100 and having stretchability, a second base material 200 extending along the first direction and facing the first base material 100 in the thickness direction, and a second wiring 210 extending along the first direction and facing the first wiring 110 in the thickness direction, and further including a connection member 300 for electrically connecting the first wiring 110 and the second wiring 210. Here, for the sake of convenience, as shown in FIGS. 1A and 1B, a region Rz including a region where the first wiring 110 and the second wiring 210 overlap in plan view is defined.
[0006] The inventors of this invention have found that when the first base material 100 and the first wiring 110 are stretched or contracted in this stretchable device 1z, as shown in Figure 2 (in Figure 2, they are stretched or contracted towards the upper right in the figure), stress is applied to region Rz. More specifically, as shown in Figure 2, the inventors have found that when a first direction, a second direction, and a stretching direction are set, stress is applied to point P in region Rz, particularly due to stretching or contraction. Point P is the outer edge 100S of the first base material 100 in region Rz, when the stretching or contraction direction is vector-decomposed into a first direction and a second direction, and is on the same side as the first direction component of the stretching or contraction direction, and on the opposite side of the second direction component of the stretching or contraction direction.
[0007] This disclosure has been made in view of the aforementioned issues. Specifically, the primary purpose of this disclosure is to provide a stretchable device with improved bonding strength.
[0008] The stretchable device according to this disclosure comprises: a first substrate that is stretchable and extends along a first direction; a first wiring that is stretchable and provided on the first substrate; a second substrate that faces the first substrate in the thickness direction of the first substrate; a second wiring provided on the second substrate that faces the first wiring in the thickness direction; and a reinforcing member provided in an overlapping region where the first substrate and the second substrate overlap in a plan view, wherein the first wiring and the second wiring are electrically connected, and the length of the reinforcing member in the second direction intersecting the first direction is longer than the length of the first substrate or the second substrate in the second direction.
[0009] According to this disclosure, it is possible to provide a stretchable device with improved bonding strength.
[0010] Figure 1A is a schematic plan view of a conventional stretchable device. Figure 1B is a schematic cross-sectional view taken along the line IB-IB in Figure 1A. Figure 2 is an explanatory diagram illustrating the stretching and contracting behavior of a conventional stretchable device. Figure 3A is a schematic plan view of a stretchable device according to the first embodiment. Figure 3B is a schematic cross-sectional view taken along the line IIIB-IIIB in Figure 3A. Figure 3C is a schematic cross-sectional view taken along the line IIIC-IIIC in Figure 3A. Figure 4A is a schematic plan view of a stretchable device according to the second embodiment. Figure 4B is a schematic cross-sectional view taken along the line IVB-IVB in Figure 4A. Figure 4C is a schematic cross-sectional view taken along the line IVC-IVC in Figure 4A. Figure 5A is a schematic plan view of a stretchable device according to the third embodiment. Figure 5B is a schematic cross-sectional view taken along the line VB-VB in Figure 5A. Figure 5C is a schematic cross-sectional view taken along the line VC-VC in Figure 5A. Figure 6A is a schematic plan view of a stretchable device according to the fourth embodiment. Figure 6B is a schematic cross-sectional view taken along the line VIB-VIB in Figure 6A. Figure 6C is a schematic cross-sectional view taken along the line VIC-VIC in Figure 6A. Figure 7A is a schematic plan view of the stretchable device of the fifth embodiment. Figure 7B is a schematic cross-sectional view taken along the line VIIB-VIIB in Figure 7A. Figure 7C is a schematic cross-sectional view taken along the line VIIC-VIIC in Figure 7A. Figure 8A is a schematic plan view of the stretchable device of the sixth embodiment. Figure 8B is a schematic cross-sectional view taken along the line VIIIB-VIIIB in Figure 8A. Figure 8C is a schematic cross-sectional view taken along the line VIIIC-VIIIC in Figure 8A. Figure 9A is a schematic plan view of the stretchable device of the seventh embodiment. Figure 9B is a schematic cross-sectional view taken along the line IXB-IXB in Figure 9A. Figure 9C is a schematic cross-sectional view taken along the line IXC-IXC in Figure 9A. Figure 10A is a schematic plan view of the stretchable device according to the eighth embodiment. Figure 10B is a schematic cross-sectional view taken along the line XB-XB in Figure 10A. Figure 10C is a schematic cross-sectional view taken along the line XC-XC in Figure 10A.
[0011] The embodiments for implementing this disclosure will be described below with reference to the drawings. The stretchable devices described below are intended to embody the technical concept of this disclosure, and unless otherwise specified, this disclosure is not limited to the following.
[0012] In this specification, "plan view" refers to the state when an object (e.g., a stretchable device) is viewed from directly above in the thickness direction, and is synonymous with a plan view. For example, a plan view is the state when viewed along the negative direction (- direction) in the "third direction" shown in Figure 3B. In this specification, "side view" refers to the state when an object is viewed from the side perpendicular to the thickness direction, unless otherwise specified, and is synonymous with a side view. For example, a side view is the state when viewed along the positive direction (or negative direction) in the "second direction" shown in Figure 3A. In this specification, "front view" refers to the state when an object is viewed from the front perpendicular to the thickness direction, unless otherwise specified, and is synonymous with a front view. For example, a front view is the state when viewed along the negative direction (- direction) in the "first direction" shown in Figure 3A. The "positive direction" mentioned above refers to the direction of the first, second, and third direction arrows shown in the drawing, while the "negative direction" refers to the direction opposite to the direction of the first, second, and third direction arrows shown in the drawing. Furthermore, the first, second, and third directions may be orthogonal to each other.
[0013] In this specification, terms describing relationships between elements (e.g., "parallel," "orthogonal," etc.) and terms describing the shapes of elements mean not only their literal, exact forms, but also a range that is substantially equivalent, for example, a range that includes differences of a few percent.
[0014] <Stretchable Device of the First Embodiment> The stretchable device 1a of the first embodiment according to this disclosure will be described with reference to Figures 3A to 3C. Figure 3A is a schematic plan view of the stretchable device of the first embodiment, Figure 3B is a schematic cross-sectional view obtained by cutting along the line IIIB-IIIB in Figure 3A, and Figure 3C is a schematic cross-sectional view obtained by cutting along the line IIIC-IIIC in Figure 3A.
[0015] The stretchable device 1a of the first embodiment comprises at least a first base material 10, a second base material 20, a first wiring 11, a second wiring 21, and a reinforcing member 30. The first wiring 11 and the second wiring 21 are electrically connected. The first base material 10 and the second base material 20 are physically connected in areas where the first wiring 11 and the second wiring 21 are not located.
[0016] The shape of the stretchable device 1a is not particularly limited. In this specification, a structure in which two substrates are connected is described as an embodiment, but three or more substrates may be connected. Also, the first wiring 11 is not limited to the arrangement shown in Figure 3A, nor is its direction of extension limited. Specifically, the direction of extension of the first substrate 10 and the direction of extension of the first wiring 11 do not have to coincide, and they do not have to extend in one direction. Furthermore, the number of first wirings 11 is not particularly limited; there may be one or more. If there are multiple first wirings 11, they may include wiring that is not electrically connected to the second wiring 21. The same applies to the arrangement and number of second wirings 21.
[0017] Furthermore, the term "above" in this specification does not necessarily correspond to the top and bottom when using the stretchable devices 1a to 1h. More specifically, as shown in Figures 3A to 3C, since the first wiring 11 and the second wiring 21 can be electrically connected, "above the first substrate 10" refers to the main surface side of the first substrate 10 that is closer to the second substrate 20, and "above the second substrate 20" refers to the main surface side of the second substrate 20 that is closer to the first substrate 10. Also, "above" an element includes not only a position above the element at a distance, i.e., a position above the element via another object or at a distance above it, but also a position directly above (on) the element in contact with it.
[0018] The following describes these components and their arrangement. As shown in Figures 3A to 3C, the first base material 10 and the second base material 20 face each other in the third direction (thickness direction) and partially overlap in a plan view. Similarly, the first wiring 11 and the second wiring 21 face each other in the third direction.
[0019] The first substrate 10 is stretchable and extends along the first direction. In this specification, "stretchable" means that it can stretch and contract by at least 10% in all directions (first direction, second direction, and third direction). The stretchability of the first substrate 1 does not hinder the stretching and contracting of the stretchable first wiring 11, which will be described later, and reduces the risk of breakage during stretching and contraction when using the stretchable device 1a.
[0020] Examples of stretchable substrates include sheet-like or film-like substrates made from stretchable resin materials. Examples of resin materials include thermoplastic polyurethane. The thickness of the stretchable substrate is not particularly limited, but from the viewpoint of not hindering the stretching and contracting of the biological surface when attached to a living body, it may be 1 mm or less, 100 μm or less, or 50 μm or less. The thickness of the stretchable substrate may also be 1 μm or more.
[0021] The first base material 10 may have a first base material end 10e. The first base material end 10e may be the end of the first base material 10 that is closer to the second base material 20 (see, for example, Figure 3B). In other words, it may be the end that overlaps with the second wiring 21 in a plan view.
[0022] Furthermore, the first base material 10 may have a first base material side end 10s. The first base material side end 10s may be both ends in the second direction in Figure 3A or Figure 3C.
[0023] The first wiring 11 is provided on the first substrate 10 and is stretchable. An example of the first wiring 11 is a mixture consisting of metal powder such as Ag, Cu, and / or Ni as conductive particles and an elastomer resin such as silicone resin. The average particle size of the conductive particles is not particularly limited, but may be 0.01 μm or more and 10 μm or less. The shape of the conductive particles may be spherical. Furthermore, the thickness, width, and length of the first wiring 11 are not particularly limited.
[0024] The second substrate 20 faces the first substrate 10 in the third direction (thickness direction). The second substrate 20 may or may not be stretchable. Examples of a second substrate 20 that is not stretchable include substrates such as FPC, FFC, or PCB. Examples of a second substrate 20 that is stretchable may be made of the same material as the first substrate 10 described above. The stretchable second substrate 20 may be a stretchable substrate of the same type as the first substrate 10 or a different type of stretchable substrate.
[0025] The second base material 20 may have a second base material end 20e. The second base material end 20e may be the end of the second base material 20 that is closer to the first base material 10 (see, for example, Figure 3B). In other words, it may be the end that overlaps with the first wiring 11 in a plan view.
[0026] Furthermore, the second base material 20 may have a second base material side end 20s. The second base material side end 20s may be both ends in the second direction in Figure 3A or Figure 3C.
[0027] The second substrate 20 may be a substrate with the same stiffness (Young's modulus) as the first substrate 10, or a substrate with higher stiffness (Young's modulus) than the first substrate 10. Therefore, the overall stiffness of the stretchable device 1a may be greater than or equal to that of the first substrate 10.
[0028] The second wiring 21 is provided on the second substrate 20 and faces the first wiring 11 in the third direction (thickness direction). The second wiring 21 may or may not be stretchable. An example of a second wiring 21 that is not stretchable is a metal wiring such as copper foil. The thickness of the second wiring 21 that is not stretchable may be 1 μm or more and 100 μm or less. An example of a stretchable second wiring 21 may be made of the same material as the first wiring 11 described above. The stretchable second wiring 21 may be the same type of stretchable wiring as the first wiring 11 or a different type of stretchable wiring. Furthermore, the second wiring 21 may be wiring with the same rigidity (Young's modulus) as the first wiring 11, or with higher rigidity (Young's modulus) than the first wiring 11.
[0029] In this embodiment, the second wiring 21 is a non-stretchable wiring, and the second substrate 20 having the second wiring 21 is a non-stretchable substrate. In this embodiment, since the second substrate 20 and the second wiring 21 are non-stretchable, their rigidity is higher than that of the first substrate 10 and the second wiring 21, thereby increasing the overall rigidity of the stretchable device. In this specification, "non-stretchable" means that the maximum elongation in all directions is less than 10%.
[0030] The first wiring 11 and the second wiring 21 are electrically connected. As an example of electrical connection, the thermoplastic properties of the stretchable substrate or stretchable wiring may be used to apply heat and pressure for fusion bonding. Alternatively, other electrical connection methods may be employed, such as using ACF (Anisotropic Conductive Film), conductive paste, or solder.
[0031] The reinforcing member 30 may be a member capable of withstanding stresses caused by the expansion and contraction of the first base material 10. For example, the stiffness (Young's modulus) of the reinforcing member 30 may be greater than or equal to the stiffness of the first base material 10, which is elastic. Also, if a non-elastic base material is used for the second base material 20, the stiffness (Young's modulus) of the reinforcing member 30 may be less than or equal to the stiffness of the second base material 20, which is a non-elastic base material. The value of Young's modulus may be based on a value described in known literature, or it may be based on a measured value of Young's modulus actually measured by known tensile tests, etc.
[0032] The reinforcing member 30 may be bonded to the first base material 10 and / or the second base material 20 so that it can withstand stress caused by expansion and contraction. For this reason, the reinforcing member 30 may be made of a thermoplastic material. For example, it may be thermoplastic polyurethane. If it is a thermoplastic material, the reinforcing member 30 and the first base material 10 and / or the second base material 20 can be bonded by heat fusion. In addition to the above, or instead, a method of bonding the reinforcing member 30 by applying an adhesive to one side of the reinforcing member 30 may be adopted.
[0033] A characteristic configuration of the stretchable device 1a of this disclosure is that the reinforcing member 30 is provided in an overlapping region Ra where the first base material 10 and the second base material 20 overlap in a plan view (see Figure 3B). In this specification, the "overlapping region" refers to the region between the end 10e of the first base material and the end 20e of the second base material in a plan view. In this embodiment, a first reinforcing member 31 disposed on the first base material 10 and a second reinforcing member 32 disposed on the second base material 20 may be provided in the overlapping region Ra. The side end 30s of the first reinforcing member 31 and the side end 30s of the second reinforcing member 32 may be bonded together (see Figure 3C). Bonding the side end 30s of the first reinforcing member 31 and the side end 30s of the second reinforcing member 32 can further improve connection reliability.
[0034] More preferably, the reinforcing member 30 may be located within the overlapping region Ra described above and provided in the connection region Rb where the first wiring 11 and the second wiring 21 overlap in a plan view (see Figure 3B). In this specification, the "connection region" refers to the region between the end 11e of the first wiring 11 and the end 21e of the second wiring 21. Reliability can be improved by suppressing the elongation of the connection portion.
[0035] Furthermore, a characteristic configuration of the stretchable device 1a of the first embodiment in this disclosure is that the length W30 of the reinforcing member 30 in the second direction intersecting the first direction is longer than the lengths W10 and W20 of the first base material 10 or the second base material 20 in the second direction (see Figure 3A). In this embodiment, the reinforcing member 30 may be configured to protrude from the first base material 10 and the second base material 20 in the second direction. In the stretchable device 1a of the first embodiment (see Figure 3A), the length of the first base material 10 in the second direction and the length of the second base material 20 in the second direction are substantially the same. In this specification, "length" refers to the width dimension of the base material, and in particular, the maximum width dimension of the base material. This dimension may be measured using known techniques, or it may be measured using techniques such as image analysis.
[0036] With the reinforcing member 30 configured in this way, the reinforcing member 30 covers point P, which is particularly susceptible to stress due to expansion and contraction as shown in Figure 2. This reduces the delamination between the first base material 10 and the second base material 20 due to stress. Therefore, it is possible to provide an expandable device with improved bonding strength.
[0037] Furthermore, in this embodiment, as shown in Figure 3A, the reinforcing member 30 may cover the connection region Rb where the first wiring 11 and the second wiring 21 overlap in a plan view. With this covering configuration of the reinforcing member 30, peeling at the electrically connected location between the first wiring 11 and the second wiring 21 can be appropriately prevented.
[0038] As a more preferable covering configuration for the reinforcing member 30, as shown in Figure 3A, the reinforcing member 30 may be provided so as to be wider than the connection area Rb and to cover the entire connection area Rb. Specifically, in a plan view, the planar area of the reinforcing member 30 may be wider than the planar area of the connection area Rb and to cover the entire connection area Rb. By employing a reinforcing member 30 wider than the connection area Rb, it is possible to more effectively prevent peeling between the first wiring 11 and the second wiring 21.
[0039] In a preferred embodiment of the stretchable device 1a of the first embodiment, at least a portion of the first wiring 11 in the connection region Rb may be covered with a stretchable protective layer 12. More specifically, the first wiring 11 may be covered with a stretchable protective layer 12 inside the connection region Rb, except at locations where the first wiring 11 and the second wiring 21 are in electrical contact. Covering the first wiring 11 with a stretchable protective layer 12 prevents the first wiring 11 from being exposed to the outside, thereby reducing short circuits and breakages of the first wiring 11. An example of the stretchable protective layer 12 is a thermoplastic elastomer (for example, thermoplastic polyurethane).
[0040] Furthermore, at least a portion of the second wiring 21 may be covered with the protective layer 22 in the connection region Rb. As described above, the second wiring 21 may be covered with the protective layer 22 in positions other than where the first wiring 11 and the second wiring 21 are in electrical contact. The protective layer 22 covering the second wiring 21 may be stretchable or non-stretchable. When the second wiring 21 is covered with the protective layer 22, it prevents the second wiring 21 from being exposed to the outside, and reduces short circuits and breakages of the second wiring 21. Examples of non-stretchable protective layers 22 covering the second wiring 21 include polyimide, LCP (liquid crystal polymer), or PET (polyethylene terephthalate).
[0041] Furthermore, as a preferred embodiment of the reinforcing member 30 of the stretchable device 1a in the first embodiment, another reinforcing member may be provided on the surface opposite to the surface on which the reinforcing member 30 is provided. In the example shown in Figure 3C, the first reinforcing member 31 may be provided so as to be in contact with the entire surface of the first substrate 10, and the second reinforcing member 32 may be provided so as to be in contact with the entire surface of the second substrate 20. When the first reinforcing member 31 and the second reinforcing member 32 are provided in this manner, the first substrate 10 and the second substrate 20 can be surrounded by the first reinforcing member 31 and the second reinforcing member 32. As a result, the reinforcing member 30 is surrounded by the first substrate 10 and the second substrate 20, and the peeling of the first substrate 10 and the second substrate 20 in the thickness direction (third direction in Figures 3B and 3C) can be more favorably improved.
[0042] In the case of the stretchable device 1a of the first embodiment, where the first reinforcing member 31 is provided so as to be in contact with the first base material 10 and the second reinforcing member 32 is provided so as to be in contact with the second base material 20, the manufacturing process may involve attaching the prepared sheet-like first reinforcing member 31 to the first base material 10, attaching the other sheet-like second reinforcing member 32 to the second base material 20, and then joining the first reinforcing member 31 and the second reinforcing member 32 together by pressing them. As mentioned above, the attachment of the reinforcing members to the base material can be done by applying an adhesive to the reinforcing member 30 and bonding them, or by using a thermoplastic reinforcing member and heat fusion.
[0043] Also, regarding the adhesive strength to the reinforcing member 30, it is preferable that the adhesive strength between the reinforcing member 30 and the first base material 10 or the second base material 20 is higher than the adhesive strength between the first wiring 11 and the second wiring 21. As an example of realizing such an adhesive strength, the material of the reinforcing member 30 is a thermoplastic elastomer (for example, thermoplastic polyurethane), the material of the first base material 10 or the second base material 20 is a thermoplastic elastomer (for example, thermoplastic polyurethane), and the material of the first wiring 11 or the second wiring 21 is a mixed material of a thermoplastic elastomer and silver. With such an adhesive strength, even if a stress is applied such that the first wiring 11 and the second wiring 21 are peeled off, since the adhesive strength between the reinforcing member 30 and the first base material 10 or the second base material 20 is high, peeling between the first wiring 11 and the second wiring 21 can be suppressed. The adhesive strength may be calculated based on the measurement results of a known tensile test or the like. The above-mentioned material of the reinforcing member 30 assumes a case where heat fusion is employed for attaching the reinforcing member 30 to the base material (the first base material 10 and the second base material 20). However, for example, when an adhesive is provided for adhesion, a reinforcing member of PET (polyethylene terephthalate), polyimide, or PP (polypropylene) having an acrylic-based, epoxy-based, or silicone-based adhesive may be employed.
[0044] <Stretchable device of the second embodiment> Next, the stretchable device 1b of the second embodiment according to the present disclosure will be described with reference to FIGS. 4A to 4C. FIG. 4A is a schematic plan view of the stretchable device of the second embodiment, FIG. 4B is a schematic cross-sectional view taken along line IVB-IVB of FIG. 4A, and FIG. 4C is a schematic cross-sectional view taken along line IVC-IVC of FIG. 4A. In the description of the stretchable device of the second embodiment, the configurations common to the stretchable device of the first embodiment will be omitted as appropriate, and the configurations different from the stretchable device of the first embodiment will be described in detail.
[0045] In the second embodiment of the expandable device 1b, the reinforcing member 30 may be provided so as to straddle the outer edge (first base material end 10e or second base material end 20e) of the first base material 10 or the second base material 20 in the first direction (see Figures 4A and 4C). In this specification, "straddle the outer edge" means to provide a member that is in contact with the two different members while sandwiching the boundary between the two different members, thereby at least covering the boundary. Specifically, in Figures 4A and 4B, the first reinforcing member 31 is provided so as to be in contact with the protective layer 22 of the first base material 10 and the second base material 20, and covers the outer edge (first base material end 10e) of the first base material 10, and the second reinforcing member 32 is provided so as to be in contact with the protective layer 12 of the first base material 10 and the second base material 20, and covers the outer edge (second base material end 20e) of the second base material 20.
[0046] In this manner, if the reinforcing member 30 is provided so as to straddle the outer edge (first base material end 10e or second base material end 20e) of the first base material 10 or the second base material 20 in the first direction, it is possible to appropriately prevent foreign matter from entering the overlapping region Ra and the connecting region Rb.
[0047] To specify the above configuration from another perspective, the reinforcing member 30 may be provided so as to extend beyond the first base material 10 or the second base material 20 in the first direction. In other words, it is sufficient for it to extend beyond the first base material 10 or the second base material 20 without having to "straddle the outer edge" as described above. Here, in this specification, "the reinforcing member 30 extending beyond the first base material 10 or the second base material 20 in the first direction" means that the reinforcing member 30 extends beyond the edge of the base material that is in contact with the reinforcing member in the first direction. To specify the above from another perspective, it can also be said that the reinforcing member 30 has a portion that does not overlap in plan view with respect to at least the first base material 10 or the second base material 20 that is in contact with the reinforcing member 30. Even with such a configuration, it is possible to prevent the ingress of foreign matter into the overlapping region Ra and the connecting region Rb more effectively than with the expandable device 1a of the first embodiment. To put it another way, it is preferable that the reinforcing member 30 is in contact with both the first base material 10 and the second base material 20.
[0048] <Stretchable Device of the Third Embodiment> Next, the stretchable device 1c of the third embodiment according to the present disclosure will be described with reference to FIGS. 5A to 5C. FIG. 5A is a schematic plan view of the stretchable device of the third embodiment, FIG. 5B is a schematic cross-sectional view taken along line VB-VB of FIG. 5A, and FIG. 5C is a schematic cross-sectional view taken along line VC-VC of FIG. 5A. In the description of the stretchable device of the third embodiment, the configurations common to the stretchable devices of the above-described embodiments will be omitted as appropriate, and the configurations different from those of the stretchable devices of the above-described embodiments will be described in detail.
[0049] In the stretchable device 1c of the third embodiment, the same reinforcing member 30 may be provided on the surface opposite to the surface on which the reinforcing member 30 is provided. More specifically, one sheet-like reinforcing member 30 may be in contact with both the first base material 10 and the second base material 20 by being folded back. In the aspect shown in FIG. 5C, the reinforcing member 30 covers the overlapping region Ra and the connection region Rb in the first base material 10, and the reinforcing member 30 protruding from the first base material 10 in the second direction may be folded back to contact the second base material 20. Further, the reinforcing member folded back to contact the second base material 20 and the reinforcing member contacting the first base material 10 may partially overlap in plan view. More preferably, as shown in FIG. 5C, the main surface of the second base material 20 different from the first base material side may be in contact with the reinforcing member 30. By adopting the structure as shown in FIG. 5C, the connection reliability can be further improved.
[0050] With such a covering aspect by the reinforcing member 30, the same effect as that of the stretchable device of the second embodiment can be obtained by using one reinforcing member 30.
[0051] Furthermore, in the case where the first base material 10 and the second base material 20 are covered with a single reinforcing member 30, as in the stretchable device 1c of the third embodiment, the manufacturing process may involve attaching the prepared sheet-like reinforcing member 30 to the first base material 10, folding back the reinforcing member 30 that extends beyond the first base material 10, attaching one end of the reinforcing member 30 to the second base material 20, and attaching the other end of the reinforcing member 30 to the second base material 20. By employing such a method, the amount of external exposure of the adhesive portion to which the reinforcing member 30 is attached can be reduced compared to the stretchable device of the second embodiment.
[0052] <Stretchable Device of the Fourth Embodiment> Next, the stretchable device 1d of the fourth embodiment according to this disclosure will be described with reference to Figures 6A to 6C. Figure 6A is a schematic plan view of the stretchable device of the fourth embodiment, Figure 6B is a schematic cross-sectional view taken along the line VIB-VIB in Figure 6A, and Figure 6C is a schematic cross-sectional view taken along the line VIC-VIC in Figure 6A. In describing the stretchable device of the fourth embodiment, configurations common to the stretchable devices of the embodiments described above will be omitted from the description as appropriate, and configurations that differ from the stretchable devices of the embodiments described above will be described in detail.
[0053] The stretchable device 1d of the fourth embodiment shows a configuration in which the second substrate 20 is larger than the stretchable first substrate 10. Specifically, the planar area of the second substrate is larger than the planar area of the first substrate 10 in a plan view, and the second substrate 20 may be provided so as to extend beyond the outer edge of the first substrate 10. Therefore, the stretchable first substrate 10 can be appropriately held by the second substrate 20 which is larger than the first substrate 10.
[0054] In the fourth embodiment of the expandable device 1d, as shown in Figures 6A to 6C, the length W30 in the second direction of the reinforcing member 30 is longer than the length W10 in the second direction of the first base material 10 and shorter than the length W20 in the second direction of the second base material 20.
[0055] To specify the above configuration from another perspective, the reinforcing member 30 may be provided so as to straddle the outer edge (first base material side end 10s) of the first base material 10 in the second direction. That is, as shown in Figures 6A and 6C, the reinforcing member 30 is provided so as to be in contact with the first base material 10 and the second base material 20 and covers the first base material side end 10s.
[0056] With the reinforcing member 30 configured in this way, the reinforcing member 30 covers at least a portion of the overlapping region Ra and the connecting region Rb, thereby effectively preventing delamination between the first substrate 10 and the second substrate 20.
[0057] Furthermore, at least the portion of the reinforcing member 30 that extends beyond the first base material 10 may be attached to the surface of the second base material 20 (the surface facing the first base material 10). Here, it is desirable that the second base material 20 to which the reinforcing member 30 is attached has high adhesive strength to the reinforcing member 30. More specifically, it is desirable that the adhesive strength of the reinforcing member 30 to the second base material 20 is higher than the adhesive strength to the first base material 10. Generally, the reinforcing member 30 has higher adhesion to non-stretchable base materials than to stretchable base materials. Therefore, by attaching the portion of the reinforcing member 30 that extends beyond the first base material 10 to the surface of the non-stretchable second base material 20, the bonding strength between the first base material 10 and the second base material 20 can be more preferably increased.
[0058] In the fourth embodiment, the stretchable device 1d may be configured such that the end of the reinforcing member 30 on the positive side in the first direction overlaps with the end of the second base material 20e in a plan view. By arranging the reinforcing member 30 in this way, the point P, which is particularly susceptible to stress due to stretching as shown in Figure 2, can be appropriately covered with the reinforcing member 30, thereby reducing the delamination between the first base material 10 and the second base material 20 due to stress. Therefore, a stretchable device with improved bonding strength can be provided.
[0059] <Stretchable Device of the Fifth Embodiment> Next, the stretchable device 1e of the fifth embodiment according to this disclosure will be described with reference to Figures 7A to 7C. Figure 7A is a schematic plan view of the stretchable device of the fifth embodiment, Figure 7B is a schematic cross-sectional view taken along the line VIIB-VIIB in Figure 7A, and Figure 7C is a schematic cross-sectional view taken along the line VIIC-VIIC in Figure 7A. In describing the stretchable device of the fifth embodiment, configurations common to the stretchable devices of the embodiments described above will be omitted from the description as appropriate, and configurations that differ from the stretchable devices of the embodiments described above will be described in detail.
[0060] In the fifth embodiment of the expandable device 1e, the reinforcing member 30 may be provided except in the connection region Rb where the first wiring 11 and the second wiring 21 overlap in a plan view. In this case, although the point P where stress due to expansion and contraction is particularly applied, as shown in Figure 2, is not covered by the reinforcing member 30 in the expandable device 1e of this embodiment, the reinforcing member 30 is provided in the overlapping region Ra where the first base material 10 and the second base material 20 overlap in a plan view. Therefore, it can be said that the bonding strength between the first base material 10 and the second base material 20 is improved compared to an expandable device without the reinforcing member 30.
[0061] In the embodiment shown in Figure 7A, the reinforcing member 30 is provided on the positive side of the first direction relative to the connection region Rb, but the reinforcing member 30 may also be provided on the negative side of the first direction relative to the connection region Rb. Furthermore, as long as the reinforcing member 30 is provided in at least the overlapping region Ra, the reinforcing member 30 may extend beyond the overlapping region Ra. Also, in Figure 7C, the length of the protective layer 12 in the second direction is shown to be smaller than the length of the second base material 20 in the second direction, but the embodiment is not limited to this. For example, the length of the protective layer 12 in the second direction and the length of the second base material 20 in the second direction may be equal.
[0062] <Stretchable Device of the Sixth Embodiment> Next, the stretchable device 1f of the sixth embodiment according to this disclosure will be described with reference to Figures 8A to 8C. Figure 8A is a schematic plan view of the stretchable device of the sixth embodiment, Figure 8B is a schematic cross-sectional view taken along the line VIIIB-VIIIB in Figure 8A, and Figure 8C is a schematic cross-sectional view taken along the line VIIIC-VIIIC in Figure 8A. In describing the stretchable device of the sixth embodiment, configurations common to the stretchable devices of the embodiments described above will be omitted from the description as appropriate, and configurations that differ from the stretchable devices of the embodiments described above will be described in detail.
[0063] In the sixth embodiment, as shown in Figures 8A to 8C, the reinforcing member 30 of the expandable device 1f may cover at least three outer edges of the first base material 10 in a plan view. Specifically, the reinforcing member 30 may cover the first base material end 10e and two first base material side ends 10s of the first base material 10 in a plan view.
[0064] To specify the above configuration from another perspective, the reinforcing member 30 may be provided so as to straddle the outer edge of the first base material 10 (the first base material end 10e and the two first base material side ends 10s) in both the first and second directions.
[0065] With the reinforcing member 30 configured in this way, the reinforcing member 30 completely covers the overlapping region Ra and the connecting region Rb, thereby effectively preventing delamination between the first substrate 10 and the second substrate 20. Furthermore, it is possible to appropriately prevent foreign matter from entering the overlapping region Ra and the connecting region Rb.
[0066] <Stretchable Device of the Seventh Embodiment> Next, the stretchable device 1g of the seventh embodiment according to this disclosure will be described with reference to Figures 9A to 9C. Figure 9A is a schematic plan view of the stretchable device of the seventh embodiment, Figure 9B is a schematic cross-sectional view taken along the line IXB-IXB in Figure 9A, and Figure 9C is a schematic cross-sectional view taken along the line IXC-IXC in Figure 9A. In describing the stretchable device of the seventh embodiment, configurations common to the stretchable devices of the embodiments described above will be omitted from the description as appropriate, and configurations that differ from the stretchable devices of the embodiments described above will be described in detail.
[0067] In contrast to the stretchable device described above, the seventh embodiment of the stretchable device 1g has the second base material 20 positioned on the positive side of the third direction and the stretchable first base material 10 positioned on the negative side of the third direction. In other words, it is intended to be an embodiment in which the first base material 10 is larger than the second base material 20.
[0068] Therefore, in the seventh embodiment of the expandable device 1g, the length in the second direction of the reinforcing member 30 may be longer than the length in the second direction of the second base material 20, and shorter than the length in the second direction of the base material of the first base material 10.
[0069] Furthermore, at least the portion of the reinforcing member 30 that extends beyond the second base material 20 may be attached to the first base material 10.
[0070] Here, the first base material 10 is stretchable. Therefore, a retaining member 40 with a rigidity higher than that of the first base material 10 may be provided on the surface of the first base material 10 opposite to the surface on which the first wiring 11 is provided. In this way, in the case of the stretchable device 1g of the seventh embodiment, since the retaining member 40 is attached to the first base material 10, deformation of the stretchable first base material 10 can be reduced, and handling during manufacturing can be made easier. Note that the retaining member 40 may be removed when the stretchable device 1g is actually used.
[0071] In addition, in the seventh embodiment of the expandable device 1g, as shown in Figures 9A to 9C, the reinforcing member 30 may cover at least three outer edges of the second base material 20 in a plan view. Specifically, the reinforcing member 30 may cover the second base material end 20e and two second base material side ends 20s of the second base material 20 in a plan view.
[0072] To specify the above configuration from another perspective, the reinforcing member 30 may be provided so as to straddle the outer edge of the second base material 20 (the second base material end 20e and the two second base material side ends 20s) in both the first and second directions.
[0073] With the reinforcing member 30 configured in this way, the reinforcing member 30 completely covers the overlapping region Ra and the connecting region Rb, thereby effectively preventing delamination between the first substrate 10 and the second substrate 20. Furthermore, it is possible to appropriately prevent foreign matter from entering the overlapping region Ra and the connecting region Rb.
[0074] <Stretchable Device of the Eighth Embodiment> Next, the stretchable device 1h of the eighth embodiment according to the present disclosure will be described with reference to Figures 10A to 10C. Figure 10A is a schematic plan view of the stretchable device of the eighth embodiment, Figure 10B is a schematic cross-sectional view taken along the line XB-XB in Figure 10A, and Figure 10C is a schematic cross-sectional view taken along the line XC-XC in Figure 10A. When describing the stretchable device of the seventh embodiment, configurations common to the stretchable devices of the embodiments described above will be omitted from the explanation as appropriate, and configurations that differ from the stretchable devices of the embodiments described above will be described in detail.
[0075] The stretchable device 1h of the eighth embodiment, like the stretchable device 1g of the seventh embodiment, has the second base material 20 positioned on the positive side of the third direction and the stretchable first base material 10 positioned on the negative side of the third direction. In other words, it is intended to be a configuration in which the first base material 10 is larger than the second base material 20. That is, in the stretchable device 1h of the eighth embodiment, the length W30 in the second direction of the reinforcing member 30 may be longer than the length W20 in the second direction of the second base material 20 and shorter than the length W10 in the second direction of the first base material 10.
[0076] In this embodiment, as shown in Figures 10A and 10B, the outer edge 30e of the reinforcing member 30 of the stretchable device 1h of the eighth embodiment may be located inward from the outer edge (first base material end 10e) of the first base material 10 located in the first direction. In other words, the outer edge 30e of the reinforcing member 30 may be located in the region where the connection region Rb and the overlapping region Ra overlap in a plan view. More specifically, the outer edge 30e of the reinforcing member 30 is located inward from the first base material end 10e of the first base material 10 which is larger than the second base material 20. In this embodiment, the first base material end 10e may not be in contact with the reinforcing member 30.
[0077] With this configuration, even if misalignment occurs when the reinforcing member 30 is attached to the second base material 20, exposure of the adhesive can be prevented.
[0078] The embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of this disclosure is not construed solely by the embodiments described above, but is defined based on the claims. Furthermore, the technical scope of this disclosure includes all modifications within the meaning and scope of equivalence to the claims.
[0079] The stretchable device of this disclosure can be suitably used as a device with improved bonding strength.
[0080] 1a-1h, 1z Stretchable device 10 First substrate 10e End of first substrate 10s Side end of first substrate 11 First wiring 12 Protective layer 11e End of first wiring 20 Second substrate 20e End of second substrate 20s Side end of second substrate 21 Second wiring 21e End of second wiring 22 Protective layer 30 Reinforcement member 30s Side end of reinforcement member 30e Outer edge of reinforcement member 31 First reinforcement member 32 Second reinforcement member 40 Holding member W10 Length W20 Length W30 Length Ra Overlapping region Rb Connection region 100 First substrate 110 First wiring 200 Second substrate 210 Second wiring 300 Connection member Rz Region
Claims
1. A stretchable device comprising: a first substrate having elasticity and extending along a first direction; a first wiring provided on the first substrate and having elasticity; a second substrate facing the first substrate in the thickness direction of the first substrate; a second wiring provided on the second substrate and facing the first wiring in the thickness direction; and a reinforcing member provided in an overlapping region where the first substrate and the second substrate overlap in a plan view, wherein the first wiring and the second wiring are electrically connected, and the length of the reinforcing member in a second direction intersecting the first direction is longer than the length of the first substrate or the second substrate in the second direction.
2. The stretchable device according to claim 1, wherein the second wiring is a non-stretchable wiring and the second substrate is a non-stretchable substrate.
3. The stretchable device according to claim 1 or 2, wherein the reinforcing member is provided so as to straddle the outer edge of the first or second substrate in the first or second direction.
4. The stretchable device according to any one of claims 1 to 3, wherein at least a portion of the first wiring is covered with a stretchable protective layer.
5. The stretchable device according to any one of claims 1 to 4, wherein at least a portion of the second wiring is covered with a protective layer.
6. The stretchable device according to any one of claims 1 to 5, wherein a reinforcing member identical to or different from the reinforcing member is provided on the surface opposite to the surface on which the reinforcing member is provided.
7. The stretchable device according to any one of claims 1 to 6, wherein the reinforcing member extends beyond the first substrate or the second substrate in the first direction.
8. The stretchable device according to any one of claims 1 to 7, wherein the reinforcing member is in contact with both the first substrate and the second substrate by folding, and in a plan view, the reinforcing member in contact with the first substrate and the reinforcing member in contact with the second substrate overlap in part.
9. The stretchable device according to any one of claims 1 to 8, wherein the reinforcing member covers the connection region where the first wiring and the second wiring overlap in a plan view.
10. The expandable device according to claim 9, wherein the reinforcing member is further provided in a location wider than the connection area.
11. The stretchable device according to any one of claims 1 to 8, wherein the reinforcing member is provided except for the connection area where the first wiring and the second wiring overlap in a plan view.
12. The stretchable device according to any one of claims 1 to 11, wherein the reinforcing member covers the outer edges of at least three sides of the first or second substrate in a plan view.
13. The stretchable device according to any one of claims 1 to 12, wherein a retaining member having a rigidity higher than the rigidity of the first substrate is provided on the surface of the first substrate opposite to the surface on which the first wiring is provided.
14. The stretchable device according to any one of claims 1 to 13, wherein the length of the reinforcing member in the second direction is longer than the length of one of the first or second substrates in the second direction, and shorter than the length of the other of the first or second substrates in the second direction.
15. The stretchable device according to claim 14, wherein the outer edge of the reinforcing member is located inward from the outer edge of the other base material located in the first direction.