Stretchable wiring substrate

Abstract

A stretchable wiring substrate 1A comprises: a stretchable base material 10A that has a first main surface 10Aa and a second main surface 10Ab opposing each other in a thickness direction T; and a wiring member 20A which is provided at least on the first main surface 10Aa side of the stretchable base material 10A, and is composed of at least one stretchable wire extending in a plane direction which includes a length direction L orthogonal to the thickness direction T, and a width direction W orthogonal to the thickness direction T and to the length direction L. The wiring member 20A includes a first wiring portion 20Aa and a second wiring portion 20Ab that both extend in the length direction L. The first wiring portion 20Aa constitutes an electric path to the outside. In the wiring member 20A, the tensile strength of the second wiring portion 20Ab in the length direction L is lower than the tensile strength of portions other than the second wiring portion 20Ab that include the first wiring portion 20Aa in the length direction L.

Description

stretchable wiring board

[0001] The present invention relates to a stretchable wiring board.

[0002] Patent Document 1 discloses a cord-like thermal fuse having a linear fuse disposed within an insulating sheathed tube, characterized in that the linear fuse is bent into a shape that allows it to stretch in its longitudinal direction.

[0003] Japanese Patent Application Publication No. 10-188756

[0004] In recent years, the condition of the human body has been managed by acquiring and analyzing biological information (vital signs) using a stretchable wiring board. When a stretchable wiring board is used in a state where it is attached to the human body, for example, the wiring used in the stretchable wiring board is required to have stretchability that allows it to follow the movement of the human body. In other words, the wiring used in the stretchable wiring board is required to be a stretchable wiring having stretchability.

[0005] However, even if the wiring used in a stretchable wiring board is a stretchable wiring, if the stretchable wiring board is stretched more than expected, the resistance of the stretchable wiring board is likely to increase as the stretchable wiring board stretches. If the resistance of the stretchable wiring increases in this way, when an excessive current flows through the stretchable wiring, the stretchable wiring may generate heat and become prone to breakage. Furthermore, if the stretchable wiring board is used while the resistance of the stretchable wiring is still high, there is a risk that errors will occur in the acquired biometric information, or that excessive current flowing through the stretchable wiring may generate heat, causing adverse effects such as burns to the human body.

[0006] In response to this, it is conceivable to incorporate a stretchable fuse such as the cord-like thermal fuse described in Patent Document 1 into a stretchable wiring board, so that when an overcurrent flows through the stretchable wiring in a state in which the stretchable wiring board is stretched more than expected, the fuse will blow, electrically destroying the stretchable wiring board. However, it is technically difficult to incorporate a cord-like thermal fuse having a hollow structure, as described in Figure 1 of Patent Document 1, into a stretchable wiring board. Even if it were possible to incorporate the cord-like thermal fuse described in Patent Document 1 into a stretchable wiring board, the stretchable wiring board would reach a high temperature when the cord-like thermal fuse blows, which could have adverse effects on the human body.

[0007] For these reasons, when a stretchable wiring board is used in a state where it is attached to the human body, a mechanism is required that can safely detect excessive stretching of the stretchable wiring board.

[0008] The present invention has been made to solve the above problems, and has an object to provide a stretchable wiring board that can safely detect an excessively stretched state.

[0009] The stretchable wiring board of the present invention comprises a stretchable substrate having a first main surface and a second main surface that face each other in a thickness direction, and a wiring member that is provided on at least the first main surface side of the stretchable substrate and is composed of at least one stretchable wire that extends in a plane direction that includes a length direction that is perpendicular to the thickness direction and a width direction that is perpendicular to the thickness direction and the length direction, wherein the wiring member includes a first wiring portion and a second wiring portion that both extend in the length direction, the first wiring portion forms an electrical path to the outside, and the tensile strength of the second wiring portion in the length direction is lower than the tensile strength of a portion of the wiring member other than the second wiring portion, including the first wiring portion, in the length direction.

[0010] According to the present invention, it is possible to provide a stretchable wiring board that can safely detect an excessively stretched state.

[0011] FIG. 1 is a schematic perspective view showing an example of a stretchable wiring board according to embodiment 1 of the present invention. FIG. 2 is a schematic perspective view showing an example of a stretchable wiring board that is a modified example of embodiment 1 of the present invention. FIG. 3 is a schematic perspective view showing an example of a stretchable wiring board according to embodiment 2 of the present invention. FIG. 4 is a schematic perspective view showing an example of a stretchable wiring board that is a modified example of embodiment 2 of the present invention. FIG. 5 is a schematic perspective view showing an example of a stretchable wiring board according to embodiment 3 of the present invention. FIG. 6 is a schematic perspective view showing an example of a stretchable wiring board that is a modified example of embodiment 3 of the present invention. FIG. 7 is a flowchart showing an example of the operation of a stretchable wiring board according to embodiment 4 of the present invention. FIG. 8 is a flowchart showing an example of the operation of a stretchable wiring board that is a modified example of embodiment 4 of the present invention.

[0012] The stretchable wiring board of the present invention will be described below. Note that the present invention is not limited to the following configurations, and may be modified as appropriate within the scope of the present invention. In addition, a combination of multiple individual preferred configurations described below also constitutes the present invention.

[0013] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. From embodiment 2 onwards, descriptions of matters common to embodiment 1 will be omitted, and differences will be mainly described. In particular, similar effects resulting from similar configurations will not be mentioned one after the other for each embodiment.

[0014] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0015] The stretchable wiring board of the present invention comprises a stretchable substrate having a first main surface and a second main surface that face each other in a thickness direction, and a wiring member that is provided on at least the first main surface side of the stretchable substrate and is composed of at least one stretchable wire that extends in a plane direction that includes a length direction that is perpendicular to the thickness direction and a width direction that is perpendicular to the thickness direction and the length direction, wherein the wiring member includes a first wiring portion and a second wiring portion that both extend in the length direction, the first wiring portion forms an electrical path to the outside, and the tensile strength of the second wiring portion in the length direction is lower than the tensile strength of a portion of the wiring member other than the second wiring portion, including the first wiring portion, in the length direction.

[0016] [First Embodiment] In a stretchable wiring board according to a first embodiment of the present invention, the first wiring section and the second wiring section are provided on different stretchable wirings.

[0017] FIG. 1 is a perspective schematic view showing an example of a stretchable wiring board according to a first embodiment of the present invention.

[0018] The stretchable wiring board 1A shown in FIG. 1 has a stretchable base material 10A and a wiring member 20A.

[0019] In this specification, the length direction, thickness direction, and width direction are defined as directions L, T, and W, respectively, as shown in Fig. 1 etc. The length direction L, thickness direction T, and width direction W are perpendicular to one another. Furthermore, a direction perpendicular to the thickness direction T and including the length direction L and width direction W is defined as a surface direction.

[0020] In this specification, unless otherwise specified, various dimensions in the length direction, thickness direction, and width direction are shown for the stretchable wiring board in an unstretched state. Various dimensions in the length direction, thickness direction, and width direction are each measured by viewing the stretchable wiring board in a plan view or cross section using an optical microscope.

[0021] The stretchable substrate 10A has a first main surface 10Aa and a second main surface 10Ab that face each other in the thickness direction T.

[0022] The stretchable substrate 10A has a narrow portion 11A having a minimum cross-sectional area when viewed in a cross section perpendicular to the length direction L.

[0023] In the example shown in Fig. 1, the dimension of the stretchable substrate 10A in the thickness direction T is constant regardless of the position along the length direction L. In other words, in the example shown in Fig. 1, the narrow portion 11A corresponds to the portion of the stretchable substrate 10A where the dimension in the width direction W is the smallest. Note that if the dimension in the width direction W of the stretchable substrate 10A is constant regardless of the position along the length direction L, the narrow portion 11A corresponds, for example, to the portion of the stretchable substrate 10A where the dimension in the thickness direction T is the smallest. In this way, the narrow portion 11A may be any portion of the stretchable substrate 10A where the cross-sectional area when viewed in a cross section perpendicular to the length direction L is the smallest, and its dimensions and the like are not particularly limited.

[0024] The stretchable substrate 10A preferably contains at least one resin selected from the group consisting of styrene-based resins, olefin-based resins, and silicone-based resins. Examples of styrene-based resins include styrene-butadiene-styrene copolymer resins (SBS).

[0025] The dimension of the stretchable substrate 10A in the thickness direction T is preferably 100 μm or less, and more preferably 50 μm or less. When the dimension of the stretchable substrate 10A in the thickness direction T is within the above range, the stretchable wiring board 1A can easily follow the movements of the human body when used in a state where it is attached to the human body.

[0026] The dimension of the stretchable substrate 10A in the thickness direction T is preferably 10 μm or more.

[0027] The breaking elongation rate of the stretchable substrate 10A in the length direction L is preferably 50% or more. When the breaking elongation rate of the stretchable substrate 10A in the length direction L is within the above range, the stretchable wiring board 1A can easily follow the movements of the human body when used in a state where it is attached to the human body.

[0028] From the viewpoint of making it easier for the stretchable wiring board 1A to follow the movements of the human body, the higher the breaking elongation rate in the length direction L of the stretchable substrate 10A is, the more preferable it is within a range of 50% or more.

[0029] The Young's modulus of the stretchable substrate 10A is preferably 100 MPa or less, and more preferably 30 MPa or less. When the Young's modulus of the stretchable substrate 10A is within the above range, when the stretchable wiring board 1A is used in a state where it is attached to the human body, the stretchable wiring board 1A is less likely to inhibit the expansion and contraction of the surface of the human body, and therefore the stretchable wiring board 1A is less likely to cause discomfort.

[0030] The Young's modulus of the stretchable substrate 10A is preferably 3 MPa or more.

[0031] In the example shown in FIG. 1, the shape of the stretchable substrate 10A when viewed in the thickness direction T is such that the dimension in the width direction W is larger at one end than at other portions.

[0032] The shape of the stretchable substrate 10A when viewed in the thickness direction T may be a shape in which the dimension in the width direction W is constant regardless of the position along the length direction L.

[0033] Furthermore, the shape of the stretchable substrate 10A when viewed in the thickness direction T may be a shape in which one end is looped, for example, a shape in which a straight portion and a loop portion are connected in the length direction L. In this case, the stretchable substrate 10A may have a narrow portion at the position where the straight portion and the loop portion are connected.

[0034] The wiring member 20A is provided on at least the first main surface 10Aa side of the stretchable substrate 10A.

[0035] In the example shown in FIG. 1, the wiring member 20A is provided on the first main surface 10Aa side of the stretchable substrate 10A.

[0036] The wiring member 20A may be provided on the second main surface 10Ab side of the stretchable substrate 10A in addition to the first main surface 10Aa side of the stretchable substrate 10A.

[0037] 1, the wiring member 20A is provided on the first main surface 10Aa of the stretchable substrate 10A. That is, in the example shown in Fig. 1, the stretchable substrate 10A and the wiring member 20A are in contact with each other.

[0038] It should be noted that another member may be interposed between the stretchable substrate 10A and the wiring member 20A.

[0039] The wiring member 20A is composed of at least one elastic wire extending in a planar direction including the length direction L and the width direction W.

[0040] In the example shown in FIG. 1, the wiring member 20A is composed of three elastic wires 21Aa, 21Ab, and 21Ac that extend in the planar direction.

[0041] The wiring member 20A may be made up of only one stretchable wire, may be made up of two stretchable wires, or may be made up of four or more stretchable wires.

[0042] The dimension in the thickness direction T of the stretchable wiring, the dimension in the thickness direction T of the stretchable wiring 21Aa, the stretchable wiring 21Ab, and the stretchable wiring 21Ac in the example shown in Fig. 1 is preferably 100 µm or less, and more preferably 50 µm or less. When the dimension in the thickness direction T of the stretchable wiring is within the above range, the stretchable wiring board 1A can easily follow the movement of the human body when used in a state where it is attached to the human body.

[0043] The dimensions of the elastic wiring in the thickness direction T, that is, the dimensions of the elastic wiring 21Aa, the elastic wiring 21Ab, and the elastic wiring 21Ac in the example shown in Figure 1 in the thickness direction T, are preferably 1 μm or more, and more preferably 10 μm or more.

[0044] The elastic wires, the elastic wires 21Aa, 21Ab, and 21Ac in the example shown in FIG. 1, contain, for example, conductive particles and a resin.

[0045] Examples of materials constituting the conductive particles contained in the elastic wiring include metals such as silver, copper, nickel, etc. Among these, silver is preferred from the viewpoint of realizing low resistance of the elastic wiring.

[0046] The average particle size of the conductive particles contained in the elastic wiring is preferably 0.01 μm or more and 10 μm or less.

[0047] The average particle size of the conductive particles contained in the stretchable wiring is determined as follows. First, the stretchable wiring substrate is polished or the like so that a cross section in which the target stretchable wiring is exposed appears. Next, an image of the cross section is taken using a scanning electron microscope (SEM) or the like. Then, the equivalent circle diameter of the conductive particles contained in the stretchable wiring is measured by performing image analysis on the taken cross section image, and the obtained equivalent circle diameter is taken as the particle size of the conductive particles. Thereafter, a number-based cumulative particle size distribution is calculated from the particle sizes of the conductive particles obtained, and the particle size at which the cumulative probability in the number-based cumulative particle size distribution is 50% (median diameter D ５０ ) is defined as the average particle size of the conductive particles.

[0048] The conductive particles contained in the stretchable wire are preferably spherical in shape. In order to reduce the change in resistance of the stretchable wire due to stretching, the conductive particles contained in the stretchable wire may have a shape other than spherical, such as a flat shape or an irregular shape having protrusions.

[0049] When the wiring member 20A is composed of multiple stretchable wirings, it is preferable that the conductive particles contained in each stretchable wiring are the same as each other at least in terms of the type of constituent material, but they may be different from each other or may be partially different.

[0050] The resin contained in the stretchable wiring is preferably at least one elastomer resin selected from the group consisting of epoxy resins, urethane resins, acrylic resins, and silicone resins. In this case, the stretchability of the stretchable wiring is more easily ensured. Note that the resin contained in the stretchable wiring may be a resin other than those listed above, as long as it can impart stretchability.

[0051] When the wiring member 20A is composed of multiple stretchable wires, it is preferable that the resin contained in each stretchable wire is the same as each other at least in terms of type, but they may be different from each other or may be partially different.

[0052] The stretchable wiring, or the stretchable wiring 21Aa, stretchable wiring 21Ab, and stretchable wiring 21Ac in the example shown in FIG. 1, is formed, for example, as follows. First, a conductive paste containing conductive particles and a resin is applied to at least the first main surface 10Aa of the stretchable substrate 10A. Examples of methods for applying the conductive paste include screen printing, inkjet printing, and dispensing. Then, the applied conductive paste is heat-treated to form the stretchable wiring.

[0053] The wiring member 20A includes a first wiring portion 20Aa and a second wiring portion 20Ab that extend in the length direction L together.

[0054] In this specification, the wiring portion (stretchable wiring) of the wiring member extending in the longitudinal direction means that the wiring portion (stretchable wiring) has a portion that extends substantially in the longitudinal direction when the wiring member is viewed as a whole. Note that the wiring portion (stretchable wiring) of the wiring member may have a portion that extends in a direction other than the longitudinal direction (for example, the width direction) as long as it has a portion that extends substantially in the longitudinal direction.

[0055] The first wiring portion 20Aa and the second wiring portion 20Ab are provided on different elastic wirings.

[0056] 1, the first wiring portion 20Aa is provided on the stretchable wiring 21Aa and the stretchable wiring 21Ab, and the second wiring portion 20Ab is provided on the stretchable wiring 21Ac. More specifically, the first wiring portion 20Aa corresponds to the entire stretchable wiring 21Aa and the stretchable wiring 21Ab, and the second wiring portion 20Ab corresponds to the entire stretchable wiring 21Ac.

[0057] The first wiring portion 20Aa, and the stretchable wiring 21Aa and the stretchable wiring 21Ab in the example shown in Fig. 1 are each electrically connected to the electronic component 30. That is, the first wiring portion 20Aa constitutes an electrical path to the outside, and in the example shown in Fig. 1, an electrical path to the external electronic component 30.

[0058] The electronic component 30 is mounted on each of the first wiring portion 20Aa, and the stretchable wiring 21Aa and the stretchable wiring 21Ab in the example shown in FIG. 1, via a joining member such as solder.

[0059] Examples of the electronic component 30 include a diode, an integrated circuit (IC), a capacitor, a resistor, an inductor, an amplifier (an operational amplifier, a transistor, etc.), and the like.

[0060] When a light-emitting diode, a type of diode, is used as the electronic component 30, for example, the first wiring unit 20Aa, and in the example shown in FIG. 1, the stretchable wiring 21Aa and the stretchable wiring 21Ab function as drive wiring through which a large current flows to drive the light-emitting diode. In this case, if the stretchable wiring board 1A is excessively stretched in the length direction L, the resistance of the first wiring unit 20Aa increases as the first wiring unit 20Aa stretches, which may make it difficult for a large current to flow to the light-emitting diode via the first wiring unit 20Aa, or may make the first wiring unit 20Aa more susceptible to breakage when a large current flows, or may make the first wiring unit 20Aa more susceptible to heat generation when a large current flows. In this way, if the stretchable wiring board 1A is excessively stretched in the length direction L, the light-emitting diode serving as the electronic component 30 may not light up, or the first wiring unit 20Aa may generate excessive heat.

[0061] In contrast, in the stretchable wiring board 1A, the wiring member 20A is provided with a second wiring portion 20Ab in addition to the first wiring portion 20Aa, and in the wiring member 20A, the tensile strength of the second wiring portion 20Ab in the length direction L is lower than the tensile strength in the length direction L of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa. In other words, the tensile strength of the second wiring portion 20Ab in the length direction L is not only lower than the tensile strength of the first wiring portion 20Aa in the length direction L, but is also the lowest of the tensile strengths in the length direction L of the wiring member 20A. As a result, when the stretchable wiring board 1A is stretched in the length direction L, the second wiring portion 20Ab will not only break before the first wiring portion 20Aa, but will also be the first to break in the wiring member 20A.

[0062] Therefore, in the stretchable wiring board 1A, by utilizing the fact that the second wiring portion 20Ab is the first to break when the stretchable wiring board 1A is stretched in the length direction L and detecting a break in the second wiring portion 20Ab, it is possible to detect an excessively stretched state of the stretchable wiring board 1A, such as the stretchable wiring board 1A being excessively stretched in the length direction L, before a malfunction such as the first wiring portion 20Aa breaking due to excessive stretching in the length direction L occurs.

[0063] Furthermore, when the stretchable wiring board 1A is used, the user can be urged to stop using the stretchable wiring board 1A at the point in time when a break in the second wiring unit 20Ab is detected when the stretchable wiring board 1A is stretched in the length direction L, that is, at the point in time before the first wiring unit 20Aa is excessively stretched in the length direction L. In other words, when the stretchable wiring board 1A is used, the user can be urged to stop using the stretchable wiring board 1A before the first wiring unit 20Aa generates excessive heat due to excessive stretching of the first wiring unit 20Aa in the length direction L when the stretchable wiring board 1A is stretched in the length direction L. Therefore, when the stretchable wiring board 1A is used, not only is the first wiring unit 20Aa prevented from generating excessive heat, but the excessive heat generated in the first wiring unit 20Aa is prevented from being exposed to the user's body, thereby improving safety.

[0064] As described above, the stretchable wiring board 1A can realize a stretchable wiring board that can safely detect an excessively stretched state.

[0065] As described above, the narrow portion 11A corresponds to the portion of the stretchable substrate 10A that has the smallest cross-sectional area when viewed in a cross section perpendicular to the longitudinal direction L. Therefore, when the stretchable wiring board 1A is stretched in the longitudinal direction L, stress tends to concentrate in the narrow portion 11A of the stretchable substrate 10A, and as a result, the narrow portion 11A is more likely to stretch than other portions.

[0066] In contrast, in the stretchable wiring board 1A, the second wiring portion 20Ab is provided at a position that overlaps the narrow portion 11A when viewed from the thickness direction T. That is, in the stretchable wiring board 1A, the second wiring portion 20Ab, which will be the first to break when the wiring member 20A is stretched in the length direction L, is provided in the narrow portion 11A, which will stretch the most when the stretchable substrate 10A is stretched in the length direction L. Therefore, according to the stretchable wiring board 1A in which the second wiring portion 20Ab is provided in the narrow portion 11A, the second wiring portion 20Ab is more likely to break earlier when stretched in the length direction L, compared to a stretchable wiring board in which the second wiring portion 20Ab is not provided in the narrow portion 11A. Therefore, in addition to making it easier to detect an excessively stretched state of the stretchable wiring board as a whole, an excessively stretched state of the stretchable wiring board can be detected earlier.

[0067] In the example shown in Figure 1, the second wiring portion 20Ab is provided at a position that overlaps the narrow portion 11A when viewed from the thickness direction T, and also at a position that does not overlap the narrow portion 11A when viewed from the thickness direction T.

[0068] The second wiring portion 20Ab may be provided only at a position overlapping the narrow portion 11A when viewed from the thickness direction T.

[0069] 1, the stretchable substrate 10A has only one narrow portion 11A, but there may be multiple narrow portions 11A. When the stretchable substrate 10A has multiple narrow portions 11A, the second wiring portions 20Ab are preferably provided in positions that overlap each narrow portion 11A when viewed from the thickness direction T. In this case, it becomes easier to detect breaks in the second wiring portions 20Ab that overlap each narrow portion 11A, and therefore it is possible to reliably detect an excessively stretched state of the entire stretchable wiring board 1A.

[0070] In addition, if the stretchable substrate 10A has multiple narrow portions 11A, the second wiring portion 20Ab may be provided in a position that overlaps some of the narrow portions 11A when viewed from the thickness direction T.

[0071] It should be noted that, for example, when the narrow portion 11A is fixed to the human body with a reinforcing material such as resin, there is a possibility that the narrow portion 11A will not be the portion that stretches the most when the stretchable substrate 10A is stretched in the length direction L. In this way, even when the narrow portion 11A is not the portion that stretches the most in the stretchable substrate 10A, by providing the second wiring portion 20Ab at a position that overlaps the portion of the entire stretchable substrate 10A that stretches mechanically most softly when viewed from the thickness direction T, it becomes easier to detect an excessively stretched state of the entire stretchable wiring board 1A, and it is also possible to detect an excessively stretched state of the stretchable wiring board 1A more quickly.

[0072] 1, the second wiring unit 20Ab is provided so as to surround the first wiring unit 20Aa when viewed from the thickness direction T. That is, in the example shown in Fig. 1, the second wiring unit 20Ab is provided outside the first wiring unit 20Aa when viewed from the thickness direction T, more specifically, on the outer edge side of the stretchable substrate 10A than the first wiring unit 20Aa. As shown in Fig. 1, when the second wiring unit 20Ab is provided on the outer edge of the stretchable substrate 10A, the area in which the second wiring unit 20Ab can detect an excessively stretched state of the stretchable wiring board 1A is expanded, making it easier to detect an excessively stretched state of the stretchable wiring board 1A.

[0073] Note that the second wiring portion 20Ab does not have to be provided so as to surround the first wiring portion 20Aa when viewed from the thickness direction T. In other words, when viewed from the thickness direction T, the second wiring portion 20Ab does not have to be provided outside the first wiring portion 20Aa, more specifically, closer to the outer edge of the stretchable substrate 10A than the first wiring portion 20Aa.

[0074] 1, the second wiring portion 20Ab is not electrically connected to any electronic component. That is, in the example shown in Fig. 1, the second wiring portion 20Ab does not form an electrical path to any external electronic component. In this case, a break in the second wiring portion 20Ab can be detected by connecting the terminals of a resistance meter (not an electronic component), which is a measuring instrument, to the second wiring portion 20Ab and measuring the resistance of the second wiring portion 20Ab as needed.

[0075] The second wiring portion 20Ab may be electrically connected to an electronic component. That is, the second wiring portion 20Ab may form an electrical path to an external electronic component. In this case, by using, for example, a light-emitting diode as the electronic component electrically connected to the second wiring portion 20Ab, it becomes possible to constantly check whether the second wiring portion 20Ab has a break based on whether the light-emitting diode is lit.

[0076] Below, we will describe an example of a wiring member 20A in which the tensile strength in the length direction L of the second wiring portion 20Ab is lower than the tensile strength in the length direction L of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa, i.e., lower than the tensile strength in the length direction L of the first wiring portion 20Aa.

[0077] When viewed in a cross section perpendicular to the length direction L of the wiring member 20A, the cross-sectional area of ​​the second wiring portion 20Ab is preferably smaller than the cross-sectional area of ​​the first wiring portion 20Aa.

[0078] When the cross-sectional area of ​​the second wiring portion 20Ab is smaller than the cross-sectional area of ​​the first wiring portion 20Aa, the cross-sectional area of ​​the second wiring portion 20Ab is preferably 10% or more and 90% or less of the cross-sectional area of ​​the first wiring portion 20Aa.

[0079] When viewed in a cross section perpendicular to the longitudinal direction L of the wiring member 20A, it is preferable that the cross-sectional area of ​​the second wiring portion 20Ab in the wiring member 20A is smaller than the cross-sectional area of ​​the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa.

[0080] In the stretchable wiring board 1A, by determining the relationship between the cross-sectional area of ​​the wiring portion and the breaking elongation rate in the length direction L of the wiring portion in advance and then setting the cross-sectional area of ​​the second wiring portion 20Ab as described above, it is possible to adjust the timing at which the second wiring portion 20Ab breaks when the stretchable wiring board 1A is stretched in the length direction L, i.e., the timing at which an excessive stretched state of the stretchable wiring board 1A is detected.

[0081] The cross-sectional areas of the first wiring portion 20Aa and the second wiring portion 20Ab may be the same.

[0082] The dimension of the second wiring portion 20Ab in the width direction W is preferably smaller than the dimension of the first wiring portion 20Aa in the width direction W. In this case, for example, even if the dimensions of the first wiring portion 20Aa and the second wiring portion 20Ab in the thickness direction T are the same, the cross-sectional area of ​​the second wiring portion 20Ab can be smaller than the cross-sectional area of ​​the first wiring portion 20Aa.

[0083] If the dimension of the second wiring part 20Ab in the width direction W is smaller than the dimension of the first wiring part 20Aa in the width direction W, it is preferable that the dimension of the second wiring part 20Ab in the width direction W be 10% or more and 90% or less of the dimension of the first wiring part 20Aa in the width direction W.

[0084] In the wiring member 20A, the dimension in the width direction W of the second wiring portion 20Ab is preferably smaller than the dimension in the width direction W of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa.

[0085] In the stretchable wiring board 1A, by determining in advance the relationship between the dimension of the wiring portion in the width direction W and the breaking elongation rate in the length direction L of the wiring portion, and then setting the dimension of the second wiring portion 20Ab in the width direction W as described above, it is possible to adjust the timing at which the second wiring portion 20Ab breaks when the stretchable wiring board 1A is stretched in the length direction L, i.e., the timing at which an excessive stretched state of the stretchable wiring board 1A is detected.

[0086] The first wiring portion 20Aa and the second wiring portion 20Ab may have the same dimensions in the width direction W. In this case, the first wiring portion 20Aa and the second wiring portion 20Ab can be easily formed under the same conditions, which tends to improve the manufacturing efficiency of the stretchable wiring board 1A.

[0087] The dimension of the second wiring portion 20Ab in the thickness direction T is preferably smaller than the dimension of the first wiring portion 20Aa in the thickness direction T. In this case, for example, even if the dimensions of the first wiring portion 20Aa and the second wiring portion 20Ab in the width direction W are the same, the cross-sectional area of ​​the second wiring portion 20Ab can be smaller than the cross-sectional area of ​​the first wiring portion 20Aa.

[0088] If the dimension of the second wiring part 20Ab in the thickness direction T is smaller than the dimension of the first wiring part 20Aa in the thickness direction T, it is preferable that the dimension of the second wiring part 20Ab in the thickness direction T be 30% or more and 90% or less of the dimension of the first wiring part 20Aa in the thickness direction T.

[0089] In the wiring member 20A, the dimension of the second wiring portion 20Ab in the thickness direction T is preferably smaller than the dimension of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa, in the thickness direction T.

[0090] In the stretchable wiring board 1A, by determining in advance the relationship between the dimension of the wiring portion in the thickness direction T and the breaking elongation rate in the length direction L of the wiring portion, and then setting the dimension of the second wiring portion 20Ab in the thickness direction T as described above, it is possible to adjust the timing at which the second wiring portion 20Ab breaks when the stretchable wiring board 1A is stretched in the length direction L, i.e., the timing at which an excessive stretched state of the stretchable wiring board 1A is detected.

[0091] The first wiring portion 20Aa and the second wiring portion 20Ab may have the same dimensions in the thickness direction T. In this case, the first wiring portion 20Aa and the second wiring portion 20Ab can be easily formed under the same conditions, for example, by using the same screen printing plate, which tends to improve the manufacturing efficiency of the stretchable wiring board 1A.

[0092] When the stretchable wiring 21Aa, the stretchable wiring 21Ab, and the stretchable wiring 21Ac are formed by applying a conductive paste using a screen printing method or the like, the dimensions of the first wiring portion 20Aa and the second wiring portion 20Ab in the thickness direction T can be adjusted by means such as applying the conductive paste multiple times.

[0093] The constituent material of the second wiring portion 20Ab may be different from the constituent material of the first wiring portion 20Aa. In this case, the constituent material of the second wiring portion 20Ab preferably has lower elongation than the constituent material of the first wiring portion 20Aa. Furthermore, the elongation rate of the constituent material of the second wiring portion 20Ab when the same load is applied is preferably lower than the elongation rate of the constituent material of the first wiring portion 20Aa. In these cases, for example, even if the cross-sectional areas of the first wiring portion 20Aa and the second wiring portion 20Ab are the same, the tensile strength of the second wiring portion 20Ab in the length direction L can be made lower than the tensile strength of the first wiring portion 20Aa in the length direction L. For example, by forming the second wiring portion 20Ab using a thermosetting paste that generally has a low fracture elongation rate, the fracture elongation rate of the second wiring portion 20Ab in the length direction L can be adjusted to be low, and therefore the tensile strength of the second wiring portion 20Ab in the length direction L can be made lower than the tensile strength of the first wiring portion 20Aa in the length direction L. In this way, by using the second wiring portion 20Ab in which the breaking elongation rate in the length direction L is adjusted to be low, it becomes possible to detect even a small elongation state of the stretchable wiring board 1A.

[0094] In the wiring member 20A, the extensibility of the constituent material of the second wiring portion 20Ab is preferably lower than the extensibility of the constituent material of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa. Furthermore, in the wiring member 20A, when the same load is applied, the extensibility of the constituent material of the second wiring portion 20Ab is preferably lower than the extensibility of the constituent material of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa.

[0095] The breaking elongation rate in the length direction L of the second wiring portion 20Ab is preferably lower than the breaking elongation rate in the length direction L of the first wiring portion 20Aa.

[0096] The breaking elongation rate in the length direction L of the second wiring portion 20Ab is preferably 10% or more and 90% or less of the breaking elongation rate in the length direction L of the first wiring portion 20Aa.

[0097] In the wiring member 20A, the breaking elongation rate in the length direction L of the second wiring portion 20Ab is preferably lower than the breaking elongation rate in the length direction L of the portion other than the second wiring portion 20Ab, including the first wiring portion 20Aa.

[0098] The stretchable wiring board 1A may further include an electrode connected to at least one of the first wiring portion 20Aa, the stretchable wiring 21Aa, and the stretchable wiring 21Ab in the example shown in FIG. 1 . The stretchable wiring board 1A can function as a sensor by being attached to the human body via such an electrode. In this case, the stretchable wiring board 1A can detect, for example, that the first wiring portion 20Aa is in an excessively stretched state in the length direction L before it breaks, i.e., before a sensor abnormality occurs. This allows the user to be prompted to stop using the stretchable wiring board 1A before a sensor abnormality occurs, thereby preventing problems such as obtaining erroneous biometric information or being diagnosed based on erroneous biometric information.

[0099] The electrodes are preferably gel electrodes. The use of gel electrodes makes it easier to attach the stretchable wiring board 1A to the human body. The gel electrodes are made of a conductive gel material containing, for example, water, alcohol, a moisturizer, an electrolyte, etc. Examples of such gel materials include hydrogels.

[0100] [Modification of First Embodiment] A stretchable wiring board according to a modification of the first embodiment of the present invention further comprises a protective member that covers at least one of the first main surface and the second main surface of the stretchable base material. Other than this, the stretchable wiring board according to the modification of the first embodiment of the present invention is the same as the stretchable wiring board according to the first embodiment of the present invention.

[0101] FIG. 2 is a perspective schematic view showing an example of a stretchable wiring board according to a modified example of the first embodiment of the present invention.

[0102] The stretchable wiring board 1A' shown in FIG. 2 further includes a protective member 40A in addition to the stretchable base material 10A and the wiring member 20A.

[0103] The protective member 40A covers at least one of the first main surface 10Aa and the second main surface 10Ab of the stretchable substrate 10A.

[0104] In the example shown in FIG. 2, the protective member 40A covers both the first main surface 10Aa and the second main surface 10Ab of the stretchable substrate 10A.

[0105] The protective member 40A may cover only the first main surface 10Aa of the stretchable substrate 10A, or may cover only the second main surface 10Ab of the stretchable substrate 10A.

[0106] 2, the protective member 40A is composed of a first protective portion 40Aa and a second protective portion 40Ab. In the example shown in Fig. 2, the first protective portion 40Aa covers the first main surface 10Aa of the stretchable substrate 10A, and the second protective portion 40Ab covers the second main surface 10Ab of the stretchable substrate 10A.

[0107] 2 , the protective member 40A, more specifically, the first protective portion 40Aa, covers the first main surface 10Aa of the stretchable substrate 10A, while also covering the wiring member 20A and the electronic component 30. By the protective member 40A covering the wiring member 20A and the electronic component 30, the following effects are obtained: - The wiring member 20A and the electronic component 30 are protected from the outside. - The moisture resistance of the wiring member 20A and the electronic component 30 is improved. - Chemical substances used in the wiring member 20A and the electronic component 30 are prevented from coming into contact with the human body. - Electric leakage from the wiring member 20A and the electronic component 30 to the human body is prevented.

[0108] The tensile strength of the protective member 40A in the length direction L, and the tensile strength of each of the first protective portion 40Aa and the second protective portion 40Ab in the length direction L in the example shown in FIG. 2 , are preferably higher than the tensile strength of the second wiring portion 20Ab in the length direction L. In this case, when the stretchable wiring board 1A′ is stretched in the length direction L, the protective member 40A does not break before the second wiring portion 20Ab. In other words, when the stretchable wiring board 1A′ is stretched in the length direction L, the protective member 40A does not break at the time when a break in the second wiring portion 20Ab is detected. Therefore, when the stretchable wiring board 1A′ is used, the user can be urged to stop using the stretchable wiring board 1A′ at the time when a break in the second wiring portion 20Ab is detected, that is, before a problem occurs such as chemical substances used in the wiring member 20A and the electronic component 30 coming into contact with the human body or electric leakage from the wiring member 20A and the electronic component 30 to the human body due to the break in the protective member 40A. As a result, safety is improved when using the stretchable wiring board 1A' having the protective member 40A.

[0109] The tensile strength in the length direction L of the protective member 40A, and the tensile strength in the length direction L of each of the first protective portion 40Aa and the second protective portion 40Ab in the example shown in Figure 2, is preferably higher than the tensile strength in the length direction L of the first wiring portion 20Aa, and more preferably higher than the tensile strength in the length direction L of all parts of the wiring member 20A.

[0110] The breaking elongation rate in the length direction L of the protective member 40A, and the breaking elongation rate in the length direction L of each of the first protective portion 40Aa and the second protective portion 40Ab in the example shown in FIG. 2, is preferably 200% or more.

[0111] The breaking elongation rate in the length direction L of the protective member 40A, and the breaking elongation rate in the length direction L of each of the first protective portion 40Aa and the second protective portion 40Ab in the example shown in FIG. 2, is preferably 800% or less.

[0112] Examples of materials that can be used to form the protective member 40A, and the first and second protective portions 40Aa and 40Ab in the example shown in FIG. 2, include elastomer resins such as polyvinyl chloride, polyethylene, polystyrene, polycarbonate, polyvinylidene fluoride, polyimide, liquid crystal polymer, polytetrafluoroethylene, phenolic resin, epoxy resin, urethane resin, acrylic resin, silicone resin, and styrene-butadiene resin.

[0113] The protective member 40A is formed, for example, by pressing a film containing the above-mentioned material onto at least one of the first main surface 10Aa and the second main surface 10Ab of the stretchable substrate 10A. Alternatively, the protective member 40A is formed, for example, by applying a slurry containing the above-mentioned material to at least one of the first main surface 10Aa and the second main surface 10Ab of the stretchable substrate 10A, and then subjecting the applied slurry to a heat treatment or UV treatment. Examples of methods for applying the slurry include screen printing, inkjet printing, and dispensing.

[0114] [Embodiment 2] In a stretchable wiring board of embodiment 2 of the present invention, the second wiring section is provided only in a position that overlaps the narrow section when viewed from the thickness direction. Except for this, the stretchable wiring board of embodiment 2 of the present invention is the same as the stretchable wiring board of embodiment 1 of the present invention.

[0115] FIG. 3 is a perspective schematic view showing an example of a stretchable wiring board according to a second embodiment of the present invention.

[0116] The stretchable wiring board 1B shown in FIG. 3 has a stretchable base material 10B and a wiring member 20B.

[0117] The stretchable substrate 10B has a first main surface 10Ba and a second main surface 10Bb that face each other in the thickness direction T.

[0118] The stretchable substrate 10B has a narrow portion 11B whose cross-sectional area is the smallest when viewed in a cross section perpendicular to the length direction L.

[0119] In the example shown in FIG. 3, the wiring member 20B is provided on the first main surface 10Ba side of the stretchable substrate 10B.

[0120] In the example shown in FIG. 3, the wiring member 20B is composed of three elastic wires 21Ba, 21Bb, and 21Bc that extend in the planar direction.

[0121] The wiring member 20B includes a first wiring portion 20Ba and a second wiring portion 20Bb that extend in the length direction L together.

[0122] The first wiring portion 20Ba and the second wiring portion 20Bb are provided on different elastic wires.

[0123] 3, the first wiring portion 20Ba is provided on the stretchable wiring 21Ba and the stretchable wiring 21Bb, and the second wiring portion 20Bb is provided on the stretchable wiring 21Bc. More specifically, the first wiring portion 20Ba corresponds to the entire stretchable wiring 21Ba and the stretchable wiring 21Bb, and the second wiring portion 20Bb corresponds to a part of the stretchable wiring 21Bc.

[0124] In the stretchable wiring 21Bc, the second wiring portion 20Bb may be electrically connected to a wiring portion adjacent to the second wiring portion 20Bb. In the stretchable wiring 21Bc, the second wiring portion 20Bb may be integrated with the wiring portion adjacent to the second wiring portion 20Bb so that no interface appears, or may not be integrated with the wiring portion adjacent to the second wiring portion 20Bb so that an interface appears.

[0125] The first wiring unit 20Ba, and the stretchable wiring 21Ba and the stretchable wiring 21Bb in the example shown in Fig. 3 are each electrically connected to the electronic component 30. That is, the first wiring unit 20Ba forms an electrical path to the outside, and in the example shown in Fig. 3, an electrical path to the external electronic component 30.

[0126] In the wiring member 20B, the tensile strength of the second wiring portion 20Bb in the length direction L is lower than the tensile strength of the portion other than the second wiring portion 20Bb, including the first wiring portion 20Ba, in the length direction L. In other words, the tensile strength of the second wiring portion 20Bb in the length direction L is not only lower than the tensile strength of the first wiring portion 20Ba in the length direction L, but is also the lowest of the tensile strengths of the wiring member 20B in the length direction L. As a result, when the stretchable wiring board 1B is stretched in the length direction L, the second wiring portion 20Bb will not only break before the first wiring portion 20Ba, but will also be the first to break in the wiring member 20B.

[0127] Therefore, according to the stretchable wiring board 1B, by utilizing the fact that the second wiring section 20Bb is the first to break when stretched in the longitudinal direction L, it is possible to realize a stretchable wiring board that can safely detect an excessively stretched state, similar to the stretchable wiring board 1A.

[0128] As described above, the narrow portion 11B corresponds to the portion of the stretchable substrate 10B that has the smallest cross-sectional area when viewed in a cross section perpendicular to the longitudinal direction L. Therefore, when the stretchable wiring board 1B is stretched in the longitudinal direction L, stress tends to concentrate in the narrow portion 11B of the stretchable substrate 10B, and as a result, the narrow portion 11B is more likely to stretch than other portions.

[0129] In contrast, in the stretchable wiring board 1B, the second wiring portion 20Bb is provided only at a position that overlaps the narrow portion 11B when viewed from the thickness direction T. Therefore, according to the stretchable wiring board 1B, similar to the stretchable wiring board 1A, the second wiring portion 20Bb is more likely to break more quickly when stretched in the length direction L, and therefore an excessively stretched state can be detected more quickly.

[0130] When viewed in a cross section perpendicular to the longitudinal direction L of the wiring member 20B, it is preferable that the cross-sectional area of ​​the second wiring portion 20Bb in the elastic wiring 21Bc is smaller than the cross-sectional area of ​​the portion other than the second wiring portion 20Bb.

[0131] In the elastic wiring 21Bc, if the cross-sectional area of ​​the second wiring portion 20Bb is smaller than the cross-sectional area of ​​the portion other than the second wiring portion 20Bb, it is preferable that the cross-sectional area of ​​the second wiring portion 20Bb is 10% or more and 90% or less of the cross-sectional area of ​​the portion other than the second wiring portion 20Bb.

[0132] In the elastic wiring 21Bc, it is preferable that the dimension in the width direction W of the second wiring portion 20Bb is smaller than the dimension in the width direction W of the portion other than the second wiring portion 20Bb.

[0133] In the elastic wiring 21Bc, if the dimension in the width direction W of the second wiring portion 20Bb is smaller than the dimension in the width direction W of the portion other than the second wiring portion 20Bb, it is preferable that the dimension in the width direction W of the second wiring portion 20Bb is 10% or more and 90% or less of the dimension in the width direction W of the portion other than the second wiring portion 20Bb.

[0134] In the elastic wiring 21Bc, it is preferable that the dimension of the second wiring portion 20Bb in the thickness direction T is smaller than the dimension of the portion other than the second wiring portion 20Bb in the thickness direction T.

[0135] In the elastic wiring 21Bc, if the dimension of the second wiring portion 20Bb in the thickness direction T is smaller than the dimension of the portion other than the second wiring portion 20Bb in the thickness direction T, it is preferable that the dimension of the second wiring portion 20Bb in the thickness direction T is 30% or more and 90% or less of the dimension of the portion other than the second wiring portion 20Bb in the thickness direction T.

[0136] In the example shown in Figure 3, the second wiring portion 20Bb is provided in two locations that overlap the narrow portion 11B when viewed from the thickness direction T, but it may be provided in only one location, or in three or more locations.

[0137] In the example shown in FIG. 3, the dimensions in the length direction L of the second wiring portions 20Bb provided at two locations may be the same as or different from each other.

[0138] [Modification of Embodiment 2] The stretchable wiring board of a modification of Embodiment 2 of the present invention further comprises a protective member that covers at least one of the first main surface and the second main surface of the stretchable base material. Other than this, the stretchable wiring board of a modification of Embodiment 2 of the present invention is similar to the stretchable wiring board of Embodiment 2 of the present invention.

[0139] FIG. 4 is a schematic perspective view showing an example of a stretchable wiring board according to a modified example of the second embodiment of the present invention.

[0140] The stretchable wiring board 1B' shown in FIG. 4 further includes a protective member 40B in addition to the stretchable base material 10B and the wiring member 20B.

[0141] In the example shown in FIG. 4, the protective member 40B covers both the first main surface 10Ba and the second main surface 10Bb of the stretchable substrate 10B.

[0142] 4, the protective member 40B is composed of a first protective portion 40Ba and a second protective portion 40Bb. In the example shown in Fig. 4, the first protective portion 40Ba covers the first main surface 10Ba of the stretchable substrate 10B, and the second protective portion 40Bb covers the second main surface 10Bb of the stretchable substrate 10B.

[0143] [Embodiment 3] In a stretchable wiring board of embodiment 3 of the present invention, the first wiring section and the second wiring section are provided on the same stretchable wiring. Except for this, the stretchable wiring board of embodiment 3 of the present invention is similar to the stretchable wiring board of embodiment 1 of the present invention.

[0144] FIG. 5 is a perspective schematic view showing an example of a stretchable wiring board according to a third embodiment of the present invention.

[0145] The stretchable wiring board 1C shown in FIG. 5 has a stretchable base material 10C and a wiring member 20C.

[0146] The stretchable substrate 10C has a first main surface 10Ca and a second main surface 10Cb that face each other in the thickness direction T.

[0147] In the example shown in FIG. 5, the wiring member 20C is provided on the first main surface 10Ca side of the stretchable substrate 10C.

[0148] In the example shown in FIG. 5, the wiring member 20C is composed of two elastic wires 21Ca and 21Cb that extend in the planar direction.

[0149] The wiring member 20C includes a first wiring portion 20Ca and a second wiring portion 20Cb that extend in the length direction L together.

[0150] The first wiring portion 20Ca and the second wiring portion 20Cb are provided on the same elastic wiring.

[0151] 5, the first wiring portion 20Ca and the second wiring portion 20Cb are provided on the stretchable wiring 21Ca and are also provided on the stretchable wiring 21Cb. More specifically, the first wiring portion 20Ca corresponds to a part of each of the stretchable wiring 21Ca and the stretchable wiring 21Cb, and the second wiring portion 20Cb corresponds to the remaining part of each of the stretchable wiring 21Ca and the stretchable wiring 21Cb.

[0152] In each of the stretchable wiring 21Ca and the stretchable wiring 21Cb, the second wiring portion 20Cb may be electrically connected to the first wiring portion 20Ca. In each of the stretchable wiring 21Ca and the stretchable wiring 21Cb, the second wiring portion 20Cb may be integrated with the first wiring portion 20Ca so that no interface appears, or may not be integrated with the first wiring portion 20Ca so that an interface appears.

[0153] The first wiring portion 20Ca is electrically connected to the electronic component 30. That is, the first wiring portion 20Ca forms an electrical path to the outside, that is, an electrical path to the external electronic component 30 in the example shown in FIG.

[0154] The second wiring portion 20Cb is connected to the first wiring portion 20Ca.

[0155] In the wiring member 20C, the tensile strength of the second wiring portion 20Cb in the length direction L is lower than the tensile strength of the portion other than the second wiring portion 20Cb, including the first wiring portion 20Ca, in the length direction L. In other words, the tensile strength of the second wiring portion 20Cb in the length direction L is not only lower than the tensile strength of the first wiring portion 20Ca in the length direction L, but is also the lowest of the tensile strengths of the wiring member 20C in the length direction L. As a result, when the stretchable wiring board 1C is stretched in the length direction L, the second wiring portion 20Cb will not only break before the first wiring portion 20Ca, but will also be the first to break in the wiring member 20C.

[0156] Therefore, according to the stretchable wiring board 1C, by utilizing the fact that the second wiring portion 20Cb is the first to break when stretched in the longitudinal direction L, it is possible to realize a stretchable wiring board that can safely detect an excessively stretched state, similar to the stretchable wiring board 1A.

[0157] The dimension of the second wiring portion 20Cb in the length direction L is preferably 1% or more and 50% or less of the dimension of the first wiring portion 20Ca in the length direction L. When the dimension of the second wiring portion 20Cb in the length direction L is in the above range relative to the dimension of the first wiring portion 20Ca in the length direction L, it becomes easy to detect an excessively stretched state of the stretchable wiring board 1C, and it becomes easy to design the resistance of the stretchable wiring.

[0158] 5, the stretchable substrate 10C has a narrow portion 11C whose cross-sectional area is the smallest when viewed in a cross section perpendicular to the length direction L, and the second wiring portion 20Cb is provided in a position that overlaps the narrow portion 11C when viewed in the thickness direction T. Therefore, according to the stretchable wiring board 1C, similar to the stretchable wiring board 1A, the second wiring portion 20Cb is more likely to break more quickly when stretched in the length direction L, and therefore an excessively stretched state can be detected more quickly.

[0159] In the example shown in Figure 5, the second wiring portion 20Cb is provided in two locations that overlap the narrow portion 11C when viewed from the thickness direction T, but it may be provided in only one location, or in three or more locations.

[0160] In the example shown in FIG. 5, the dimensions in the length direction L of the second wiring portions 20Cb provided at two locations may be the same as or different from each other.

[0161] [Modification of Embodiment 3] A stretchable wiring board according to a modification of Embodiment 3 of the present invention further comprises a protective member that covers at least one of the first main surface and the second main surface of the stretchable base material. Other than this, the stretchable wiring board according to a modification of Embodiment 3 of the present invention is the same as the stretchable wiring board according to Embodiment 3 of the present invention.

[0162] FIG. 6 is a schematic perspective view showing an example of a stretchable wiring board according to a modified example of the third embodiment of the present invention.

[0163] The stretchable wiring board 1C' shown in FIG. 6 further includes a protective member 40C in addition to the stretchable base material 10C and the wiring member 20C.

[0164] In the example shown in FIG. 6, the protective member 40C covers both the first main surface 10Ca and the second main surface 10Cb of the stretchable substrate 10C.

[0165] 6, the protective member 40C is composed of a first protective portion 40Ca and a second protective portion 40Cb. In the example shown in Fig. 6, the first protective portion 40Ca covers the first main surface 10Ca of the stretchable substrate 10C, and the second protective portion 40Cb covers the second main surface 10Cb of the stretchable substrate 10C.

[0166] [Embodiment 4] The stretchable wiring board of embodiment 4 of the present invention further includes a detection unit that checks the energization state of the second wiring section while the stretchable wiring board is in use, a determination unit that checks whether or not there is a break in the second wiring section based on information about the energization state of the second wiring section checked by the detection unit, and a transmission unit that transmits information that a break in the second wiring section has been detected.

[0167] FIG. 7 is a flowchart showing an example of the operation of the stretchable wiring board according to the fourth embodiment of the present invention.

[0168] First, a user starts using the stretchable wiring board attached to his or her body, and at this time, the stretchable wiring board is stretched in the length direction.

[0169] Next, in step S11 shown in FIG. 7, the detection unit checks the energization state of the second wiring unit while the stretchable wiring board is in use.

[0170] In this case, for example, a resistance meter may be used as the detection unit to measure the resistance of the second wiring portion as needed, thereby checking the current-carrying state of the second wiring portion.

[0171] Furthermore, for example, a detection circuit having a light-emitting diode connected to the second wiring section may be provided as a detection section, and the electrical conduction state of the second wiring section may be confirmed by checking the lighting state of the light-emitting diode at any time.

[0172] Next, in step S12 shown in FIG. 7, the determination unit determines whether or not the second wiring portion is disconnected based on the information on the current-carrying state of the second wiring portion confirmed by the detection unit.

[0173] In this case, for example, if a resistance meter is used as the detection unit to measure the resistance of the second wiring portion at any time, the judgment unit may determine that the second wiring portion has been broken when the resistance of the second wiring portion becomes equal to or greater than a threshold value.

[0174] Furthermore, for example, if a detection circuit in which a light-emitting diode is connected to the second wiring section is provided as a detection section and the lighting state of the light-emitting diode is checked at any time, the judgment section may determine that the second wiring section has been broken when the light-emitting diode changes from a lighting state to an off state.

[0175] The determination unit may be, for example, a resistance meter serving as a detection unit, a determination circuit connected to a detection circuit, or the like.

[0176] If it is not determined that the second wiring portion is disconnected, the determination process by the determination portion in step S12 described above is performed again.

[0177] Next, if the determination unit determines that the second wiring unit is disconnected, the transmitting unit transmits information that the second wiring unit is disconnected, in step S13 shown in FIG.

[0178] In this case, for example, if a detection circuit having a light-emitting diode connected to the second wiring portion is provided as the detection portion, the light-emitting diode may change from a lit state to an extinguished state to notify the user that a break in the second wiring portion has been detected, thereby transmitting information. In this case, the light-emitting diode connected to the second wiring portion functions as the transmitter.

[0179] Furthermore, for example, the transmitter may be provided with an alert circuit that issues an alert when the second wiring section is broken, and the alert issued by the alert circuit may be shown to the user to transmit information that a break in the second wiring section has been detected. Examples of ways of issuing an alert include displaying an alert message on a monitor or the like, generating an alert sound, turning on an alert lamp, etc.

[0180] The user can stop using the stretchable wiring board by checking the information that the disconnection of the second wiring part has been detected, which is transmitted by the transmitting part in step S13. This allows the user to stop using the stretchable wiring board at the time when the disconnection of the second wiring part is detected, i.e., before the first wiring part is excessively stretched in the length direction.

[0181] [Variation of Embodiment 4] A stretchable wiring board according to a variation of Embodiment 4 of the present invention further includes a control unit that stops the supply of current to the first wiring unit in conjunction with the transmission of information from the transmission unit that a break in the second wiring unit has been detected. Except for this point, the stretchable wiring board according to a variation of Embodiment 4 of the present invention is the same as the stretchable wiring board according to Embodiment 4 of the present invention.

[0182] FIG. 8 is a flowchart showing an example of the operation of the stretchable wiring board according to the modified example of the fourth embodiment of the present invention.

[0183] Steps S11, S12, and S13 shown in FIG. 8 are the same as those in FIG.

[0184] Next, in step S14 shown in FIG. 8, in response to the transmitting unit transmitting information that a break in the second wiring unit has been detected, the control unit stops the supply of current to the first wiring unit.

[0185] The control unit may be, for example, a control circuit that can stop the supply of current to the first wiring unit in response to the transmission of information from the transmission unit that a break in the second wiring unit has been detected. The control circuit may or may not be directly connected to the first wiring unit.

[0186] The timing at which the control unit stops supplying current to the first wiring unit may be the same timing at which the transmitting unit transmits information that a break in the second wiring unit has been detected, or may be the timing after the transmitting unit transmits information that a break in the second wiring unit has been detected.

[0187] In step S14, the control unit stops the supply of current to the first wiring unit, thereby forcibly stopping use of the stretchable wiring board. This makes it possible to reliably stop use of the stretchable wiring board at the time when a break in the second wiring unit is detected, i.e., before the first wiring unit is excessively stretched in the length direction.

[0188] In each of the above embodiments, a mode in which the stretchable wiring board is stretched in the length direction when the stretchable wiring board is used has been described. However, the stretchable wiring board may be stretched in a surface direction other than the length direction (for example, the width direction) in addition to the length direction.

[0189] The present specification discloses the following:

[0190] <1> A stretchable wiring board comprising: a stretchable substrate having a first main surface and a second main surface opposing each other in a thickness direction; and a wiring member provided on at least the first main surface side of the stretchable substrate and consisting of at least one stretchable wire extending in a plane direction including a length direction perpendicular to the thickness direction and a width direction perpendicular to the thickness direction and the length direction, wherein the wiring member includes a first wiring portion and a second wiring portion that both extend in the length direction, and the first wiring portion constitutes an electrical path to the outside, wherein the tensile strength of the second wiring portion in the length direction is lower than the tensile strength of a portion of the wiring member other than the second wiring portion, including the first wiring portion, in the length direction.

[0191] <2> The stretchable wiring board according to <1>, wherein the first wiring section and the second wiring section are provided on different stretchable wirings.

[0192] <3> The stretchable wiring board according to <1>, wherein the first wiring section and the second wiring section are provided on the same stretchable wiring.

[0193] <4> The stretchable wiring board according to <3>, wherein the dimension of the second wiring portion in the length direction is 1% or more and 50% or less of the dimension of the first wiring portion in the length direction.

[0194] <5> When viewing a cross section perpendicular to the length direction of the wiring member, the cross-sectional area of ​​the second wiring portion is smaller than the cross-sectional area of ​​the first wiring portion. The stretchable wiring board according to any one of <1> to <4>.

[0195] <6> The stretchable wiring board according to <5>, wherein the dimension of the second wiring portion in the width direction is smaller than the dimension of the first wiring portion in the width direction.

[0196] <7> The stretchable wiring board according to <5> or <6>, wherein the dimension of the second wiring portion in the thickness direction is smaller than the dimension of the first wiring portion in the thickness direction.

[0197] <8> The stretchable wiring board according to any one of <1> to <7>, wherein the constituent material of the second wiring portion is different from the constituent material of the first wiring portion.

[0198] <9> The stretchable substrate has a narrow portion having a minimum cross-sectional area when viewed in a cross section perpendicular to the length direction, and the second wiring portion is provided at a position overlapping the narrow portion when viewed in the thickness direction. The stretchable wiring board according to any one of <1> to <8>.

[0199] <10> The stretchable wiring board according to any one of <1> to <9>, further comprising a protective member covering at least one of the first main surface and the second main surface of the stretchable base material.

[0200] <11> The stretchable wiring board according to any one of <1> to <10>, further comprising: a detection unit that confirms the energization state of the second wiring section during use of the stretchable wiring board; a determination unit that determines whether or not there is a break in the second wiring section based on information about the energization state of the second wiring section confirmed by the detection unit; and a transmission unit that transmits information that a break in the second wiring section has been detected.

[0201] <12> The stretchable wiring board according to <11>, further comprising a control unit that stops the supply of current to the first wiring unit in conjunction with the transmission of information that a break in the second wiring unit has been detected by the transmission unit.

[0202] 1A, 1A', 1B, 1B', 1C, 1C' Stretchable wiring board 10A, 10B, 10C Stretchable base material 10Aa, 10Ba, 10Ca First main surface 10Ab, 10Bb, 10Cb Second main surface 11A, 11B, 11C Narrowed portion 20A, 20B, 20C Wiring member 20Aa, 20Ba, 20Ca First wiring portion 20Ab, 20Bb, 20Cb Second wiring portion 21Aa, 21Ab, 21Ac, 21Ba, 21Bb, 21Bc, 21Ca, 21Cb Stretchable wiring 30 Electronic component 40A, 40B, 40C Protective member 40Aa, 40Ba, 40Ca First protective portion 40Ab, 40Bb, 40Cb Second protective portion L Length direction S11, S12, S13, S14 Step T Thickness direction W Width direction

Claims

1. An elastic substrate having a first main surface and a second main surface opposed to each other in a thickness direction; A wiring member provided on at least the first main surface side of the elastic base material and extending in a surface direction including a length direction perpendicular to the thickness direction and a width direction perpendicular to the thickness direction and the length direction, the wiring member being composed of at least one elastic wiring; the wiring member includes a first wiring portion and a second wiring portion that extend together in the longitudinal direction, the first wiring portion forms an electrical path to an external device; In the wiring member, a tensile strength in the length direction of the second wiring portion is lower than a tensile strength in the length direction of a portion other than the second wiring portion, the portion including the first wiring portion; A stretchable wiring board, characterized in that a constituent material of the second wiring portion is different from a constituent material of the first wiring portion.

2. An elastic substrate having a first principal surface and a second principal surface opposed to each other in a thickness direction; A wiring member provided on at least the first main surface side of the elastic base material and extending in a surface direction including a length direction perpendicular to the thickness direction and a width direction perpendicular to the thickness direction and the length direction, the wiring member being composed of at least one elastic wiring; the wiring member includes a first wiring portion and a second wiring portion that extend together in the longitudinal direction, the first wiring portion forms an electrical path to an external device; In the wiring member, a tensile strength in the length direction of the second wiring portion is lower than a tensile strength in the length direction of a portion other than the second wiring portion, the portion including the first wiring portion; The stretchable substrate has a narrow portion having a minimum cross-sectional area when viewed in a cross section perpendicular to the longitudinal direction, The stretchable wiring board, characterized in that the second wiring portion is provided at a position overlapping the narrow portion when viewed from the thickness direction.

3. The stretchable wiring board according to claim 1 or 2, wherein the first wiring portion and the second wiring portion are provided on different stretchable wirings.

4. The stretchable wiring board according to claim 1 or 2, wherein the first wiring portion and the second wiring portion are provided on the same stretchable wiring.

5. The stretchable wiring board according to claim 4 , wherein the dimension of the second wiring portion in the length direction is 1% or more and 50% or less of the dimension of the first wiring portion in the length direction.

6. The stretchable wiring board according to claim 1 or 2, wherein when viewed in a cross section perpendicular to the longitudinal direction of the wiring member, a cross-sectional area of ​​the second wiring portion is smaller than a cross-sectional area of ​​the first wiring portion.

7. The stretchable wiring board according to claim 6 , wherein a dimension of the second wiring portion in the width direction is smaller than a dimension of the first wiring portion in the width direction.

8. The stretchable wiring board according to claim 6 , wherein a dimension of the second wiring portion in the thickness direction is smaller than a dimension of the first wiring portion in the thickness direction.

9. The stretchable substrate has a narrow portion having a minimum cross-sectional area when viewed in a cross section perpendicular to the longitudinal direction, The stretchable wiring board according to claim 1 , wherein the second wiring portion is provided at a position overlapping the narrow portion when viewed in the thickness direction.

10. The stretchable wiring board according to claim 1 or 2, further comprising a protective member covering at least one of the first main surface and the second main surface of the stretchable base material.

11. A detection unit that checks the energization state of the second wiring portion during use of the stretchable wiring board; a determination unit that determines whether or not the second wiring portion is disconnected based on information on the current-carrying state of the second wiring portion confirmed by the detection unit; and The stretchable wiring board according to claim 1 or 2, further comprising a transmitter that transmits information that a break in the second wiring portion has been detected.

12. The stretchable wiring board according to claim 11, further comprising a control unit that stops the supply of current to the first wiring unit in response to the transmission of information from the transmission unit that a break in the second wiring unit has been detected.