Structure, method for manufacturing the structure, and method for using the structure

Abstract

The present invention provides a structure in which the rate of increase in resistance is small even after repeated expansion and contraction, a method for manufacturing the structure, and a method for using the structure. [Solution] A structure 100 comprising a sheet-like stretchable base material 1 and stretchable wiring 2 arranged on at least one surface of the stretchable base material 1, wherein one or the opposite surface of the stretchable base material 1 is in contact with the object to be attached, and the structure is attached so as to expand and contract with the movement of the object to be attached, wherein even when the object to be attached is in a state where the length of the structure 100 in at least one direction is minimized, the structure 100 is in a state that is more extended in the aforementioned one direction than when no tensile force acts on the structure 100 and residual strain is approximately zero.

Description

Technical Field

[0001] The present invention relates to a structure, a method for manufacturing the structure, and a method for using the structure.

Background Art

[0002] In recent years, due to the increasing interest in health, the need for biosensing has been growing. Also, with the progress of robot development, the application of sensors to robots is desired. For biosensors and robot sensors, the application of flexible substrates and flexible wirings has been studied initially, but the problem has arisen that simply having flexibility cannot follow the complex shapes of the human body and robots. For example, it is possible to form the side surface of a cylinder or a cone with a flexible substrate, but it is impossible to form a sphere without wrinkles. Therefore, it is impossible to cover a shape similar to a sphere, for example, the elbow or knee, without wrinkles.

[0003] On the other hand, stretchable substrates and stretchable wirings have been developed (see, for example, Patent Document 1). If the substrate has stretchability, it can follow a complex shape. For example, it becomes possible to cover the elbow and knee.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non - Patent Documents

[0005]

Non - Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, it is known that when a stretchable substrate is repeatedly stretched and compressed, the electrical resistance of the stretchable wiring gradually increases (see, for example, Non-Patent Document 1). If this electrical resistance is within an acceptable range, it can be used, but if it exceeds the acceptable range, it becomes problematic for use as an electronic circuit. In other words, the large increase in the electrical resistance of the wiring when stretched and compressed was the problem.

[0007] This invention has been made in view of the circumstances of the prior art, and aims to provide a structure in which the rate of increase in the resistance value of the installed expandable wiring is small even after repeated expansion and contraction. It also aims to provide a method for manufacturing the structure and a method for using the structure. [Means for solving the problem]

[0008] According to one aspect of the present invention, a structure is provided comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein one or the opposite surface of the stretchable base material is in contact with an object to be attached, and the structure is attached so as to expand and contract with the movement of the object to be attached, and even when the object to be attached is in a state where the length of the structure in at least one direction is minimized, the structure is in a state that is more extended in one direction than in a state where no tensile force acts on the structure and residual strain is approximately zero.

[0009] Furthermore, according to another aspect of the present invention, a method for manufacturing a structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the one surface or the opposite surface of the stretchable base material is in contact with an object to be attached and the structure expands and contracts in accordance with the movement of the object to be attached, wherein the maximum dimensions of the stretchable base material that can be taken during the attachment process, and the minimum and maximum dimensions of the stretchable base material that can be taken during the attachment process are assumed, and the maximum dimensions of the stretchable base material that can be taken during the attachment process are less than or equal to the maximum dimensions of the stretchable base material that can be taken during the attachment process, and the relationship between the maximum strain and residual strain of the stretchable base material used is such that during the attachment process A method for manufacturing a structure is provided, comprising the steps of: designing the initial length L0 of a stretchable substrate such that the maximum possible dimension of the stretchable substrate corresponds to "initial length L0 × (1 + maximum strain Smax)" and the minimum possible dimension of the stretchable substrate during installation is greater than or equal to "initial length L0 × (1 + residual strain Sr)"; printing stretchable wiring on one side of a stretchable substrate having a non-stretchable film on the opposite side, based on the design results from the design step; separating the stretchable substrate into individual pieces having stretchable wiring after the printing step; and removing the non-stretchable film after the separation step.

[0010] Furthermore, according to another aspect of the present invention, there is a method for using a structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein one or the opposite surface of the stretchable base material is in contact with a workpiece and the structure is attached so as to expand and contract with the movement of the workpiece, wherein the structure is attached to a workpiece when the length of the structure in at least one direction is at its minimum, in a state where it is stretched in at least one direction and the strain is greater than the expected residual strain in that direction, and the method for using the structure is provided in a region where the strain in one direction of the stretchable base material during attachment is greater than the expected residual strain.

[0011] Furthermore, the phrase "one or the opposite side of the stretchable substrate is in contact with the object to be attached" is not limited to direct contact, but also includes cases where one or the opposite side of the stretchable substrate is indirectly in contact with the object via another film, such as a cover film. [Effects of the Invention]

[0012] According to the present invention, it is possible to suppress the increase in resistance associated with repeated expansion and contraction operations, thereby extending the usable life of the structure. [Brief explanation of the drawing]

[0013] [Figure 1] These are plan views (a), (b), (d), (e) and explanatory diagrams (c), (f) showing an example of a structure according to the first embodiment of the present invention. [Figure 2] This is an explanatory diagram showing the wiring length of the expandable wiring of a structure according to the first embodiment of the present invention, showing the wiring length in the state before installation (a), the state with maximum strain (b), the state with residual strain (c), and during installation (d). [Figure 3] This is an explanatory diagram showing an example of a method for attaching a structure according to the first embodiment of the present invention. [Figure 4] These are plan views (a) to (c) and cross-sectional views (a') to (c') showing an example of a manufacturing method for the structure shown in Figure 1 or Figure 3 according to the first embodiment of the present invention. [Figure 5] Figure 4 shows plan views (a), (b) and cross-sectional views (a'), (b') of the same, continuing the manufacturing method of the structure shown in Figure 4. [Figure 6] These are plan views (a), (b), (d), (e) and explanatory diagrams (c), (f) showing an example of a structure according to a second embodiment of the present invention. [Figure 7] This is an explanatory diagram showing an example of a method for attaching a structure according to a second embodiment of the present invention. [Figure 8] These are plan views (a) to (d) and cross-sectional views (a') to (d') showing an example of a manufacturing method for the structure shown in Figure 6 or Figure 7 according to a second embodiment of the present invention. [Figure 9] Figure 8 shows a continuation of the manufacturing method of the structure, with plan views (a) to (c) and cross-sectional views (a') to (c') thereof. [Figure 10] These are plan views (a), (b), (d), (e) and explanatory diagrams (c), (f) showing an example of a structure according to a third embodiment of the present invention. [Figure 11]It is an explanatory diagram showing an example of a method for mounting a structure according to a third embodiment of the present invention. [Figure 12] It is a plan view (a) to (d) and a cross-sectional view (a') to (d') thereof showing an example of a method for manufacturing a structure shown in FIG. 10 or FIG. 11 according to a third embodiment of the present invention. [Figure 13] It is a plan view (a), (b) and a cross-sectional view (a'), (b') thereof showing the continuation of the method for manufacturing the structure shown in FIG. 12. [Figure 14] It is a plan view (a), (b), (d), (e) and an explanatory diagram (c), (f) showing an example of a structure according to a fourth embodiment of the present invention. [Figure 15] It is an explanatory diagram showing an example of a method for mounting a structure according to a fourth embodiment of the present invention. [Figure 16] It is a plan view (a) to (d) and a cross-sectional view (a') to (d') thereof showing an example of a method for manufacturing a structure shown in FIG. 14 or FIG. 15 according to a fourth embodiment of the present invention. [Figure 17] It is a plan view (a), (b) and a cross-sectional view (a'), (b') thereof showing the continuation of the method for manufacturing the structure shown in FIG. 16. [Figure 18] It is an explanatory diagram showing the wiring length of the stretchable wiring of the structure used for the description of the example, showing the state (a) before mounting, the state (b) where the maximum strain occurs, and the state (c) where the residual strain to the maximum strain is repeated. [Figure 19] It is a graph showing the relationship between the maximum strain and the residual strain in a structure having a stretchable base material A and a stretchable wiring B. [Figure 20] It is a graph showing the correspondence between the cycle (number of repetitions) of the repeated test and the wiring resistance, showing the change in the resistance value (characteristic line L3) of the structure according to the present invention and the change in the resistance value (characteristic line L4) of the conventional structure. [Figure 21] It is a graph showing the relationship between the maximum strain and the residual strain in a structure having a stretchable base material C and a stretchable wiring D. [Figure 22] It is an example of a comparison result comparing the change in the resistance value in the structure of the present invention when a tensile force is applied to the structure with the change in the resistance value in the conventional structure. [Figure 23] This is an explanatory diagram showing the wiring length of expandable wiring in a conventional structure, and it shows the state before installation (a), the state with maximum strain (b), the state with residual strain (c), and the state where the dimensions from pre-installation to maximum strain are repeated (d). [Figure 24] This graph illustrates a method for designing the maximum and minimum strain during installation in a structure having an expandable base material C and expandable wiring D. [Figure 25] This graph illustrates a method for designing the maximum and minimum strain during installation in a structure having a stretchable base material A and a stretchable wiring B. [Figure 26] These are explanatory diagrams necessary for explaining a method for manufacturing the structure shown in Figure 1 or Figure 3 according to the first embodiment of the present invention, and are plan views (a) to (b) and cross-sectional views (a') to (b') showing the process when manufacturing the structure shown in Figure 4(b) (cross-sectional view (b')) by multi-panel mounting. [Figure 27] Figure 26 shows plan views (a), (b) and cross-sectional views (a'), (b') of the same, continuing the manufacturing method of the structure shown in Figure 26. [Figure 28] Figure 27 shows a plan view (a) and a cross-sectional view (a') of the same, continuing the manufacturing method of the structure shown in Figure 27. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the drawings used below are not drawn to an exact scale for the sake of clarity. That is, the drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from reality. Within the scope of this disclosure, the layers do not necessarily have to be stacked in the order shown in the drawings. Furthermore, layers not shown in these drawings may be added. Also, the embodiments described below are illustrative examples of configurations for embodying the technical idea of ​​this disclosure, and the technical idea of ​​this disclosure is not limited to the materials, shapes, and structures of the components described below. The technical idea of ​​this disclosure can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0015] Furthermore, the terms "left / right" and "up / down" in the following explanation are merely definitions for the sake of explanation and do not limit the technical concept of this disclosure. Therefore, for example, if the page is rotated 90 degrees, "left / right" and "up / down" will be swapped when read, and if the page is rotated 180 degrees, "left" will become "right" and "right" will become "left".

[0016] [Embodiment] [First Embodiment] Figure 1 shows an example of the schematic configuration of the structure according to the first embodiment. The structure 100 includes a stretchable base material 1, stretchable wiring 2 provided on one side of the stretchable base material 1, and an elongation sensor 2S. In the first embodiment, the elongation sensor 2S is made of the same material as the stretchable wiring 2. In Figure 1, Figure 1(a) is a plan view showing the wiring length of the stretchable wiring 2 of the structure 100 before it is attached to the body to be attached; Figure 1(b) is a plan view showing the wiring length of the stretchable wiring 2 when maximum strain Smax occurs due to the application of tensile force when the structure 100 is attached to the body to be attached (arm 3) as shown in Figure 1(c); Figure 1(d) is a plan view showing the wiring length of the stretchable wiring 2 after residual strain Sr occurs after the application of tensile force that causes maximum strain Smax has been stopped; and Figure 1(e) is a plan view showing the wiring length of the stretchable wiring 2 immediately after the structure 100 is attached to the body to be attached (arm) 3 as shown in Figure 1(f).

[0017] Let me explain in more detail. The stretchable base material 1 has a substantially rectangular shape. Multiple stretchable wires 2 are formed on one surface of the stretchable base material 1. These multiple stretchable wires 2 are arranged parallel to each other at regular intervals along the longitudinal direction of the stretchable base material 1. These multiple stretchable wires 2 have the same length and are formed to extend to near both ends of the stretchable base material 1 in the longitudinal direction, and terminal portions 2C are formed at both ends of each stretchable wire 2. Figure 1 shows the case where there are two stretchable wires 2. The number of stretchable wires 2 may be two or more.

[0018] Near one end of the stretchable wiring 2, a wire is connected between two adjacent stretchable wirings 2, approximately perpendicular to each other, forming an elongation sensor 2S. The wire forming the elongation sensor 2S is made of the same material as the stretchable wiring 2. Figure 1(a) shows the initial state of structure 100. The initial state is the state before tensile force is applied, and refers to a state in which no tensile force has ever been applied, such as immediately after the structure 100 has been created and completed. It may also include a state in which tensile force has been applied but the residual strain is approximately zero. In other words, the initial state may be a state in which no tensile force is currently applied and the residual strain is approximately zero.

[0019] The initial length L0 of the expandable wiring 2 (length between terminals 2C) is defined as the initial length L0 and is used as the reference dimension. The initial length L0 may be the length of the expandable wiring 2 when the structure 100 is completed, or when no tensile force is applied and no residual strain has occurred. It is sufficient that the length of the expandable wiring 2 is approximately the same as the length of the expandable wiring 2 at the time of design (completion).

[0020] Figure 1(b) shows the structure 100 stretched by applying a tensile force in the longitudinal direction (left-right direction in Figure 1(b)). When attaching the structure 100 to the object to be attached, as shown in Figure 1(c), the structure 100 is attached to the side of the object to be attached (in this case, near the elbow 3A of the arm 3) in the stretched state, i.e., with the stretchable wiring 2 stretched. The length of the stretchable wiring 2 in the state of the structure 100 shown in Figure 1(b) is defined as the maximum dimension in the longitudinal direction (left-right direction) (=L0 × (1 + Smax)). Smax is the maximum strain. The maximum strain here refers to the strain (elongation rate) in the longitudinal direction of the stretchable base material 1 when the stretch is greatest during the attachment process, that is, when the wiring length of the stretchable wiring 2 is stretched to its maximum dimension by stretching the structure 100 in order to attach it to the object to be attached.

[0021] Figure 1(d) shows the residual dimensions (=L0 × (1 + Sr)) when the tensile force is reduced to "0" after applying tensile force to the stretchable wiring 2 until it reaches its maximum dimensions. Here, Sr is the residual strain. Note that in Figure 1(d), the structure 100 is shown with a dashed line because it is not necessary to actually go through the state shown in Figure 1(d), i.e., it is a reference diagram. Figure 1(e) shows the dimensions of the expandable wiring 2 while the structure 100 is attached to the object to be attached, as shown in Figure 1(f). As shown in Figure 1(e), the wiring length of the expandable wiring 2 while attached is longer than the initial length L0 and shorter than the maximum dimension "L0 × (1 + Smax)". Also, the wiring length of the expandable wiring 2 is longer than the residual dimension "L0 × (1 + Sr)" and shorter than the maximum dimension "L0 × (1 + Smax)".

[0022] As shown in Figure 1(f), the structure 100 is installed so as to be in contact with the part to be detected by the extension sensor 2S, for example, the protruding part of the elbow 3A, and is fixed to the wearer by surface joining the longitudinal ends of the structure 100. The joint portion 100a of the longitudinal ends is positioned opposite the side of the elbow 3A. The reason for positioning the joint portion 100a opposite the side of the elbow 3A is that the dimensional change in the length direction of the arm on the side is smaller than the dimensional change on the front of the protruding part of the elbow 3A, that is, even when the elbow 3A is bent and straightened, the stress on the joint portion 100a is small and the joint portion 100a is less likely to peel off. In other words, it is preferable that the structure 100 is attached to the wearer such that the joint portion 100a of the structure 100 is close to the part of the wearer excluding the position in the circumferential direction of the wearer where the length of the cylindrical portion of the structure 100 attached to the wearer changes the most during attachment.

[0023] In this invention, the definition of residual strain Sr is the value of strain when the stress is 0 at the 100th cycle when the assumed dimensions of the stretchable wiring 2 change from L0 to L0 × (1 + Smax) to L0, based on the time dependence of strain and stress when a tensile test is performed for 100 consecutive cycles in which the assumed dimensions of the stretchable wiring 2 change from L0 to L0 × (1 + Smax) to L0. However, the speed from L0 to L0 (1 + Smax) is 10 [% / sec], and the speed from L0 (1 + Smax) to L0 is -10 [% / sec]. Here, "assumed dimensions" refers to the dimensions between the clamping fixtures of the tensile testing machine, and coincides with the sample dimensions when there is no slack.

[0024] Figure 2 shows the dimensional change of the stretchable wiring 2 in the present invention when the arm of the wearer is repeatedly bent and straightened with the structure 100 in contact with the protruding part of the elbow 3A, as shown in Figure 1. Figure 2(a) corresponds to the initial state shown in Figure 1(a), where the tensile force in the left-right direction is 0. Figure 2(b) shows the state when the longitudinal length of the structure 100 reaches its expected maximum value when the structure 100 is attached to the wearer (corresponding to Figure 1(b)), and a tensile force is applied to the longitudinal direction of the structure 100 (left-right direction in Figure 2(b)). If the tensile force is reduced to 0 from this state, the structure 100 will shrink to L0(1+Sr) as shown in Figure 2(c), but it will not return any further because residual strain is generated in the stretchable base material 1.

[0025] When the structure 100 is attached to the body to be worn, a tensile force is applied such that the length of the elastic wiring 2 of the structure 100 becomes longer than L0 × (1 + Sr) when the elbow 3A is extended. Then, when the arm 3 is bent and extended during wear, for example, the length of the elastic wiring 2 becomes a value greater than L0, as shown by the arrow in Figure 2(d), and will only fluctuate within the range from L0 to L0 × (1 + Smax). In addition, the length of the elastic wiring 2 will be a value greater than the residual dimension L0 × (1 + Sr), that is, the length of the elastic wiring 2 will only fluctuate within the range from the residual dimension L0 × (1 + Sr) to the maximum dimension L0 × (1 + Smax).

[0026] The dimensional change indicated by arrow Y in Figure 2(d) corresponds to the change in the length of the expandable wiring 2 when the arm 3 is bent and extended. The dimensional change was experimentally investigated by measuring the amount of elongation around the elbow 3A. Specifically, a stretchable supporter that fits snugly to the arm, including the elbow 3A, was prepared. Points were drawn on the supporter at 10mm intervals in the direction parallel to the arm, starting from the protrusion of the elbow 3A and moving towards the wrist and towards the shoulder. Points were also drawn at 10mm intervals in the direction perpendicular to these points, i.e., around the arm. The points around the arm were drawn along a straight line passing through the protrusion of the elbow 3A when the supporter was worn on the arm, moving from the thumb side to the little finger side.

[0027] Next, a supporter marked with these points was attached to the arm, and the distance between the points was measured with the elbow 3A extended and with the elbow 3A bent. Then, the dimensional change due to bending the elbow 3A was investigated by dividing the distance between the points with the elbow 3A bent by the distance between the points with the elbow 3A extended. As a result, the local elongation rate in the direction parallel to the arm was +10%, +20%, +20%, +20%, +30%, +40%, +40%, +40%, +40%, +20%, and +30% from the wrist side to the shoulder side, indicating that it elongates by up to about 40% near the occipital protuberance, and that the elongation rate differs depending on the location. At the same time, the localized stretch rates in the direction of the arm circumference were +20%, +20%, +30%, +10%, +10%, +20%, +30%, +30%, +20%, and +10% from the thumb side to the little finger side, indicating that the arm can stretch up to approximately 30% in the direction of the arm circumference, and that the stretch rate varies depending on the location.

[0028] From these results, it can be seen that, similarly, when the structure 100 according to the present invention is attached to the arm, the stretchable base material 1 stretches by up to approximately 40% in the vertical direction (parallel to the arm = the direction in which the stretch sensor 2S extends) when the arm 3 is bent, but at the same time stretches by up to approximately 30% in the horizontal direction (perpendicular to the arm = the direction in which the stretchable wiring 2 extends). This horizontal stretching causes the stretching and contracting of the stretchable wiring 2 in the direction in which the wiring extends. In other words, when the structure 100 is applied to the elbow 3A, it can be seen that, for example, (1+Smax) / (1+Sr)≧1.3 must be satisfied in order for the stretch sensor 2S to detect the bending and extending of the arm 3 when the arm 3 is bent and extended.

[0029] On the other hand, Figure 23 shows the dimensional change of a conventional stretchable wiring when the arm 3 is bent and extended. The structure is similar to the structure in this embodiment, comprising a rectangular sheet-like stretchable base material and a pair of stretchable wirings arranged on one side of the stretchable base material, with wiring forming an elongation sensor connected perpendicularly to the pair of stretchable wirings. Note that the elongation sensor is not shown in Figure 23.

[0030] In Figure 23, (a) is the initial state, where the tensile force in the left-right direction is 0. Figure 23(b) shows the state when the length of the structure (stretchable wiring) is at its maximum during the attachment process of attaching the structure to the object to be attached, and a tensile force in the left-right direction is applied. If the tensile force is reduced to 0 from this state, the stretchable base material will shrink to L0 × (1 + Sr) as shown in Figure 23(c), but will not return to its original size due to residual strain. If the structure is attached to the object to be attached while the arm 3 is extended and no tensile force is applied to the stretchable base material, the structure will remain at its original size without changing its size, and residual strain will occur in the stretchable base material, resulting in a slightly slack state as shown in Figure 23(d). At this time, as the arm 3 is bent and extended, the wiring length of the stretchable wiring of the structure will fluctuate within the range of L0 to L0 × (1 + Smax), as shown by the arrow in Figure 23(d).

[0031] Here, as shown in Figure 2, when the wiring length of the stretchable wiring 2 changes between L0 × (1 + Sr) and L0 × (1 + Smax), the structure 100 adheres closely to the elbow 3A, i.e., the arm 3, so the movement of the stretchable base material 1 is smooth and the mechanical load on the stretchable wiring 2 is distributed. In contrast, in the conventional case shown in Figure 23, residual strain occurs in the stretchable base material 1 when the wiring length of the stretchable wiring is in the range of L0 to L0 × (1 + Sr), and since the wiring length of the stretchable base material 1 remains at L0 × (1 + Sr), undulation occurs, the stretchable base material does not adhere closely to the body (elbow), the movement is not uniform, and the mechanical load is concentrated locally (at the peaks and troughs of the undulation), which accelerates the deterioration of the stretchable wiring 2.

[0032] Figures 1(c) and 1(f) show examples of the structure 100 being attached with its surface (the side on which the elastic wiring 2 is formed) facing away from the human body (arm), that is, the side of the structure 100 on which the elastic wiring 2 is not formed (the back side) in contact with the arm 3. The dashed line in Figure 1(c) indicates that the elastic wiring 2 is viewed from the back side. Figure 1(f) shows the structure 100 in a cylindrical shape attached to the human body. In Figure 1(f), when attaching the structure 100, the back side of one end of the structure 100 in the longitudinal direction is joined to the back side of the other end. Adhesive or hook-and-loop fastener may be used for joining.

[0033] Although Figure 1 does not show the flexible wiring board or protective film, the structure 100 typically includes a flexible wiring board 4, which will be described later. The structure 100 may also have a protective film 5 covering the stretchable wiring 2. Alternatively, a protective film (not shown) may be provided not only on the surface but also on the back side of the stretchable substrate 1. A hook-and-loop fastener is a well-known structure that allows for easy attachment and detachment of surfaces. In a hook-and-loop fastener, a hook-shaped element on one surface catches on a loop-shaped fiber on the other surface for fastening. Alternatively, a mushroom-shaped hook on one surface intertwines with another mushroom-shaped hook on the other surface for fastening. Hook-and-loop fasteners are typically made of nylon or similar material. Double-sided tape can be used to attach hook-and-loop fasteners to a structure, but liquid adhesive may also be used.

[0034] Figures 3(a) and 3(b) show examples of the structure 100 being attached with its surface facing the human body. The dashed line in Figure 3(b) indicates that the stretchable wiring 2 is being viewed from the back. Figure 3(b) shows the structure 100 in a cylindrical shape attached to the human body. In Figure 3(b), when attaching the structure 100, the surface of one end of the structure 100 in the longitudinal direction is joined to the surface of the other end. Adhesive or hook-and-loop fastener may be used for joining.

[0035] Although Figure 3 does not show the flexible wiring board or protective film, the structure typically includes a flexible wiring board 4, which will be described later. It may also have a protective film 5 covering the stretchable wiring 2. Alternatively, a protective film (not shown) may be provided not only on the surface but also on the back side of the stretchable substrate 1. In Figure 3(b), the protective film on the front side of the stretchable substrate 1 is effective and important in preventing the stretchable wiring 2 from directly contacting the skin and malfunctioning. Furthermore, if the structure 100 has a flexible wiring board, the terminals will not short-circuit at the joint surface.

[0036] An example of a manufacturing method for the structure shown in Figure 1 or Figure 3 will be explained later using Figures 24 and 25, and also Figures 4 and 5.

[0037] First, the design method will be explained using Figure 24. The arm circumference is measured assuming a cylindrical sample (structure) is attached to the arm. Let Lmin be the arm circumference when the elbow is extended, and Lmax be the arm circumference when the elbow is bent. These are the minimum and maximum dimensions while the sample is attached. Note that the arm circumference referred to here is the length in the circumferential direction when the arm is considered as a cylinder, and refers to the arm circumference at the location where the wiring is located.

[0038] Furthermore, the maximum dimension during installation is less than or equal to the maximum dimension L00(1+Smax) during the installation process, and the minimum dimension during installation is greater than or equal to the residual dimension L00(1+Sr). Here, "L00" is the initial length of the substrate in the area being stretched, the maximum dimension L00(1+Smax) during the installation process represents the dimension when stretched to its maximum extent during the installation process, and the residual dimension L00(1+Sr) represents the dimension to which the substrate returns to its original state when the tensile force on it, stretched to its maximum dimension during installation, is reduced to zero. Smax is the maximum strain, and Sr is the residual strain. Here, the "area being stretched" is the area of ​​the sample in which the dimensions can change, for example, in Figure 1(f), it is the area excluding the joined portion. Also, for example, in Figure 7(a), it can be the area excluding the joined portion. This is because, in Figure 7(a), the joined portion has twice the thickness, so the elongation for the same tensile force is small, and furthermore, since it includes the flexible wiring board 4, the elongation can be ignored compared to the normal "area being stretched".

[0039] In Figure 24, the horizontal axis represents maximum strain, and the vertical axis represents maximum strain and residual strain. Characteristic line L5 represents maximum strain, and characteristic line L6 represents residual strain. Figure 24 shows the properties when epoxy-based stretchable substrate C is used as the stretchable substrate 1. Note that, like Figure 21 described later, Figure 24 shows the properties of characteristic lines L5 and L6, but in Figure 24, the display range of the vertical axis is expanded from -100% to 150% compared to Figure 21.

[0040] In Figure 24, the main point of the present invention is to perform expansion and contraction operations so that the strain changes between the characteristic line L6 of residual strain and the characteristic line L5 of maximum strain. In Figure 24, the vertical axis from -100% to L5 represents "1 + Smax". The vertical axis from -100% to L6 represents "1 + Sr". For example, if the maximum change in length in the arm circumference direction (position dependent) is ΔLmin / ΔLmax = 1 / 1.3 = 0.77, then a line is drawn as auxiliary line L7 at a position corresponding to 0.77 times the length from -100% to L5 on the vertical axis. Since this auxiliary line L7 must be greater than or equal to residual strain L6, it can be seen that the maximum strain Smax in Figure 24 should be 70% or greater, which is the maximum strain Smax at the point where residual strain L6 and auxiliary line L7 intersect.

[0041] If we assume the point where the maximum strain Smax = 70% is used, then Lmin / L00 ≥ 1 + Sr = 131%. It is best to set Lmin / L00 to a smaller value within this range. For example, if we use Lmin / L00 = 131%, then Lmin = 250 mm and Lmax = 310 mm, so L00 = 190 mm and Lmax / L00 = 163%, satisfying Lmax / L00 ≤ 170%.

[0042] Alternatively, if we adopt the point of maximum strain at 100%, then Lmin / L00 ≥ 1 + Sr = 154%. For example, if we adopt Lmin / L00 = 154%, then Lmin = 250 mm and Lmax = 310 mm, so L00 = 162 mm and Lmax / L00 = 191%, satisfying Lmax / L00 ≤ 200%. In this way, L00 can be determined from the maximum strain and residual strain data shown in Figure 24, and from the values ​​of ΔLmin / ΔLmax, Lmin, and Lmax.

[0043] Next, Figure 25 shows the properties when an epoxy-based stretchable substrate A is used as the stretchable substrate 1. In Figure 25, the horizontal axis represents maximum strain, and the vertical axis represents maximum strain and residual strain. Characteristic line L1 represents maximum strain, and characteristic line L2 represents residual strain. Figure 25 shows the characteristics of characteristic lines L1 and L2, similar to Figure 19 described later, but in Figure 25, the display range of the vertical axis is expanded to a range from -100% to 150%.

[0044] In Figure 25, the vertical axis from -100% to L1 represents "1 + Smax". The vertical axis from -100% to L2 represents "1 + Sr". For example, if the maximum value of the change in length in the arm circumference direction (position dependent) is ΔLmin / ΔLmax = 1 / 1.3 = 0.77, then a line is drawn as auxiliary line L7 at a position of 0.77 on the vertical axis from -100% to L1. Since this L7 must be greater than or equal to the residual length L2, it can be seen that the maximum strain Smax should be greater than or equal to 40%, which is the maximum strain Smax when the residual strain L2 and the auxiliary line L7 intersect in Figure 25.

[0045] If we adopt the point where the maximum strain is 40%, then Lmin / L00 ≥ 1 + Sr = 108%. It is best to set Lmin / L00 to a smaller value within this range. For example, if we adopt Lmin / L00 = 108%, then Lmin = 250 mm and Lmax = 310 mm, so L00 = 231 mm and Lmax / L00 = 134%, satisfying Lmax / L00 ≤ 140%. In this way, L00 can be determined from the maximum strain and residual strain data shown in Figure 25, and from the values ​​of ΔLmin / ΔLmax, Lmin, and Lmax.

[0046] Next, the manufacturing process of the structure 100 using "L00" designed as described above will be explained with reference to Figures 4 and 5. In Figure 4, (a') to (c') are cross-sectional views of the AA' section of (a) to (c), and similarly, in Figure 5, (a') to (b') are cross-sectional views of the AA' section of (a) to (b). In the plan views of Figures 4 and 5, for clarity, only the terminal section 4B consisting of conductive wiring viewed from the back is shown with dashed lines. Also, only the vicinity of the connection part is shown for the flexible wiring board 4 itself, and the parts connected to it are omitted. Furthermore, although Figures 4 and 5 show the flexible wiring board 4 having two terminal sections 4B, it may have more terminal sections 4B.

[0047] First, a rectangular, sheet-like stretchable substrate 1 is prepared. However, it is desirable that one side of the stretchable substrate 1 has a non-stretchable release film 1R (Figure 4(a), (a')). Hereafter, the side of the stretchable substrate 1 on which the release film 1R is formed will be referred to as the back side, and the other side as the front side.

[0048] As the stretchable base material 1, a material with a Young's modulus of 100 kPa or more and 100 MPa or less, called an elastomer, which stretches with a small tensile force and tends to return to its original shape when the tension is released, is preferred. Urethane, epoxy, acrylic, and silicone materials can be used. As the non-stretchable release film 1R, a material with a Young's modulus of 100 MPa or more and 10 GPa or less, which deforms only slightly with a small force, is preferred. PET, PEN, PI, etc. can be used. When using a non-stretchable resin as the release film 1R, it is preferable to have a release layer such as silicone or fluororesin (not shown) on the release film 1R side of the stretchable base material 1.

[0049] Next, the stretchable wiring 2, terminal portion 2C, and elongation sensor 2S are formed on the surface of the stretchable substrate 1 (Figure 4(b), (b')). In the first embodiment, the elongation sensor 2S is made of the same material as the stretchable wiring 2 and is formed simultaneously in the same process. It is desirable for the stretchable wiring 2 to have low electrical resistance. However, normally, the electrical resistance of the stretchable wiring 2 and the elongation sensor 2S increases when the wiring constituting these components is stretched, and decreases when it is contracted. The elongation sensor 2S can detect elongation using this characteristic. Furthermore, by performing a known four-wire measurement, the influence of the resistance of the stretchable wiring 2 can be eliminated, and the resistance of the elongation sensor 2S can be measured purely. Note that measurement is not possible if the resistance of the stretchable wiring 2 is extremely high.

[0050] The material for the stretchable wiring 2 and the stretch sensor 2S is preferably a mixture of elastomer (urethane, epoxy, acrylic, silicone, etc.) and metal particles (silver, etc.). Screen printing is preferred for the manufacturing method, but dispenser printing or nozzle printing may also be used. Furthermore, it is preferable to apply the materials to a large-area stretchable substrate 1 in multiple directions up to this step, and after forming the stretchable wiring 2, the stretchable substrate 1 is cut and fragmented using a pinnacle die 20 or the like.

[0051] Specifically, the processing is carried out as shown in Figures 26 to 28. Figures 26(a) and (a') show the stretchable base material 1 formed not individually but in a multi-panel configuration, as shown in Figure 4(b). A pinnacle die 20 for separating these multi-panel components into individual pieces is set on the stage of the press machine (Figures 26(b), (b')), the sample is placed face down on top of it, and then the PET film 21 is placed on top of that, and pressed by the rollers 22 of the press machine (Figures 27(a), (a')). However, the PET film 21 is not shown in Figure 27(a), and the rollers 22 are not shown in Figure 27(a'). The sample pressed by the roller 22 of the press machine is then cut out by the pinnacle die 20 (Figures 27(b), (b'). Note that the PET film 21 is not shown in Figure 27(b). The cut-out pieces (Figures 28(a), (a')) correspond to the components in Figures 4(b), (b'). Alignment can be achieved by aligning the alignment mark 2M for the pinnacle die, which is formed simultaneously with the stretchable wiring 2, with the pinnacle die 20.

[0052] To the member formed in this manner, as shown in Figures 4(b) and (b'), a flexible wiring board 4 is further connected to the terminal portion 2C of the stretchable wiring 2 on the surface of the stretchable substrate 1 (Figures 4(c) and (c')). The flexible wiring board 4 has conductive wiring (connecting electrodes) (terminal portion) 4B (usually copper) formed on a non-stretchable insulating film 4A (usually polyimide), and a part of it is covered with a coverlay (usually polyimide, not shown). The surface of the copper terminal portion 4B is gold-plated.

[0053] Conventionally, the shape of the polyimide film at the connection edge of the flexible wiring board 4 with the stretchable substrate 1 is straight, and multiple terminal portions 4B are formed in a row along the connection edge of the flexible wiring board 4. In other words, conventional flexible wiring boards 4 do not have slits 4S between opposing terminal portions 4B.

[0054] However, in this embodiment, it is desirable to provide slits 4S between multiple terminal portions 4B arranged along the connection edge of the flexible wiring board 4. The presence of slits 4S between terminal portions 4B allows the structure 100 to be subjected to expansion and contraction forces in the vertical direction (the direction in which the connection edge extends) as shown in Figure 4(c). In this case, the portion of the expandable substrate 1 opposite to the portion between terminal portions 4B (i.e., between terminal portions 2C) primarily bears the responsibility for expansion and contraction. This suppresses expansion and contraction in the terminal portion 4B portion and the opposing portion (terminal portion 2C), thereby preventing damage to the connection portion between the flexible wiring board 4 (terminal portion 4B) and the terminal portion 2C. For the connection between the flexible wiring board 4 and the terminal portion 2C, an anisotropic conductive film having conductive particles in the resin is preferred, and among anisotropic conductive films, those containing acrylic resin that can be connected at low temperatures or those containing thermoplastic resin are preferred.

[0055] Next, a stretchable protective film 5 is attached to cover all or part of the exposed portion of the stretchable wiring 2 on the stretchable substrate 1 (Figures 5(a), (a'). The protective film 5 is made of a protective film with a non-stretchable back release film 5R on one side and an adhesive 5A applied to the other side, and is attached so that the adhesive 5A side is in contact with the stretchable wiring 2. At this time, the joint of the flexible wiring board 4 may also be covered with the protective film 5 as shown in Figure 5(a). Urethane, acrylic, epoxy, and silicone types can be used for the protective film 5. PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and PI (polyimide) are preferred for the back release film 5R. Urethane, acrylic, epoxy, and silicone types are preferred for the adhesive 5A.

[0056] Finally, the release film 1R on the back of the stretchable substrate 1 and the release film 5R on the back of the protective film are peeled off. This completes the structure of the present invention and provides the structure in its initial state (Figure 5(b), (b')). However, if a protective film is to be applied to the back of the stretchable substrate 1, after peeling off the release film 1R on the back of the stretchable substrate 1, the adhesive side of the stretchable protective film (with a non-stretchable release film on the back) is attached to the back of the stretchable substrate 1. Then, the release film 5R on the back of the front protective film 5 and the release film on the back protective film (not shown) are peeled off. This completes the structure of the present invention and provides the structure in its initial state.

[0057] When using hook-and-loop fasteners to attach a structure to a workpiece by joining the back surfaces of the structures as shown in Figure 1(f), either do not apply a back protective film to the area where the hook-and-loop fasteners are to be attached, or apply a back protective film and then peel off the back release film before adhering the hook-and-loop fastener members to both ends of the back surface, and then peel off the back release film 5R of the protective film on the front side of the stretchable base material 1.

[0058] As shown in Figure 3(b), when using hook-and-loop fasteners to join the surfaces of the structures and attach them to the object to be attached, peel off the back release film 5R of the front protective film 5, adhere the hook-and-loop fastener members to both ends of the surface, and then peel off the back release film of the protective film on the back side of the stretchable base material 1.

[0059] [Operation and Effects of the First Embodiment] For example, as shown in Figure 1(c), when attaching the structure 100 to the elbow 3A, the structure is attached such that when the arm 3 is bent and extended, the dimensions of the elastic wiring 2 change between L0×(1+Sr) and L0×(1+Smax), as shown in Figure 2(d). First, with the arm 3 extended, the structure 100 is positioned so that it is approximately perpendicular to the arm 3 and facing the elbow 3A. Then, the structure 100 is wrapped around the arm 3 while being pulled on both sides in its longitudinal direction, and surface-bonded using hook-and-loop fasteners or adhesive attached to both ends. At this time, the structure is attached so that the length of the elastic wiring 2 is longer than L0×(1+Sr) and shorter than L0×(1+Smax), but as close to L0×(1+Sr) as possible. The elastic base material 1, which is formed of sheet-like urethane or epoxy, is attached in close contact with the elbow 3A.

[0060] When the arm 3 is bent from this position, the stretchable base material 1 attached to the elbow 3A deforms smoothly along with the change in surface shape accompanying the movement of the elbow 3A, and the wiring acting as an elongation sensor 2S, which is mounted parallel to the direction of extension of the arm 3, stretches in accordance with the bending motion of the arm 3. Subsequently, when the arm 3 is extended, the elongation sensor 2S contracts, that is, the wiring acting as the elongation sensor 2S contracts. As the wiring acting as the elongation sensor 2S expands and contracts, signals corresponding to this expansion and contraction are extracted from the four terminal sections 2C. By passing current between two terminals at one end of the four terminal sections 2C and measuring the voltage between the two terminals at the other end, the resistance of the bending sensor can be accurately evaluated, and the bending motion of the arm 3 and the amount of that motion can be detected.

[0061] Furthermore, as the arm 3 bends and extends, the elastic wiring 2, which extends in a direction approximately perpendicular to the direction in which the arm 3 extends, also expands and contracts. By repeatedly bending and extending the arm 3, the elastic wiring 2 also repeatedly expands and contracts. Here, the structure 100 is installed such that the length of the stretchable wiring 2 is longer than L0 × (1 + Sr) and shorter than L0 × (1 + Smax). The residual strain Sr is the residual strain that occurs when the stretchable base material 1 is stretched until the maximum strain Smax occurs.

[0062] When the structure 100 is attached to the body to be attached, if the structure 100 is attached along the arm 3 without being stretched, residual strain will occur in the stretchable base material 1 as the arm 3 bends and extends. As shown in Figure 23, when the arm 3 is extended, the stretchable base material 1 will sag and become wavy, and the mechanical load will concentrate locally. This will accelerate the deterioration of the stretchable wiring 2, and as a result, the electrical resistance will gradually increase, and the detection accuracy of the stretch sensor 2S will decrease.

[0063] In contrast, in this embodiment, the structure 100 is stretched and attached to the object to be attached, and is stretched to a length greater than the residual strain. Therefore, even when the arm 3 is bent and extended, the structure 100 remains stretched beyond the residual strain of the stretchable base material 1, and no slack occurs in the stretchable base material 1. As a result, deterioration of the stretchable wiring 2 caused by slack in the stretchable base material 1 is suppressed, and consequently, a decrease in the detection accuracy of the stretch sensor 2S can be suppressed. In other words, the usable period of the structure can be extended.

[0064] Furthermore, since the film thickness and wire width of the stretchable wiring 2 are sufficiently smaller than the thickness and width of the stretchable substrate 1, the expansion and contraction of the stretchable wiring 2 is governed by the expansion and contraction of the stretchable substrate 1. Therefore, the residual strain of the stretchable substrate 1 affects the stretchable wiring 2. Also, if the stretchable substrate 1 stretches by X times, the stretchable wiring 2 in the same direction will also stretch by X times. Consequently, the condition that the maximum length of the stretchable wiring 2 is L0(1+Smax) or less and the minimum length is L0(1+Sr) or more is equivalent to the condition that the maximum length of the stretchable substrate 1 in the same direction is L00(1+Smax) or less and the minimum length is L00(1+Sr) or more. Here, L0 is the initial length of the stretchable wiring 2, and L00 is the initial length of the stretchable substrate 1.

[0065] Furthermore, although the stretchable wiring 2 is formed on only one side of the stretchable base material 1, the stretchable wiring 2 may be formed on both sides of the stretchable base material 1. Also, although two stretchable wirings 2 are formed, two or more stretchable wirings 2 may be formed.

[0066] Furthermore, although the stretchable wiring 2 is formed parallel to one direction, it may be formed in multiple directions. In this case, for each stretchable wiring 2 with a different direction of stretching, tensile force is applied to the stretchable base material 1 in multiple directions along the direction in which the stretchable wiring 2 stretches, such that it is longer than L0 × (1 + Sr) and shorter than L0 × (1 + Smax), thereby suppressing the deterioration of the stretchable wiring in multiple directions. Also, although the case with one stretch sensor has been described, multiple stretch sensors may be provided. Similarly, slits 4S may be provided between adjacent stretchable wirings 2 among three or more stretchable wirings 2.

[0067] Furthermore, the stretchable base material 1 only needs to have one side in contact with the object to be attached. The stretchable base material 1 may be in direct contact with the object to be attached, or the surface of the stretchable base material 1 may be indirectly in contact with the object to be attached via a separately provided film such as a cover film.

[0068] [Second Embodiment] Next, a second embodiment of the present invention will be described. The second embodiment replaces the elongation sensor 2S with a load sensor 9. An example of the structure 101 according to the second embodiment is shown in Figure 6. In the second embodiment, the structure 101 shown in Figure 6 comprises a stretchable base material 1, stretchable wiring 2 formed on one side of the stretchable base material 1, and a load sensor 9.

[0069] The load sensor 9 comprises a lower electrode 6, a ferroelectric layer 7, and an upper electrode 8. The lower electrode 6 is formed on a stretchable substrate 1. The ferroelectric layer 7 is formed to cover a portion of the lower electrode 6, extending from a part of the upper surface of the lower electrode 6 to the stretchable substrate 1. The upper electrode 8 is formed from the portion of the upper surface of the ferroelectric layer 7 that overlaps with the lower electrode 6, covering its sides and extending to the stretchable substrate 1. The lower electrode 6, the ferroelectric layer 7, and the upper electrode 8 overlap in some areas. A pair of terminal portions 2C are formed at the end of the stretchable substrate 1 on the load sensor 9 side, and the lower electrode 6 and the upper electrode 8 are connected to the terminal portions 2C by stretchable wiring 2. The stretchable wiring 2 is arranged parallel to the width direction or parallel to the longitudinal direction of the stretchable substrate 1.

[0070] In Figure 6, Figure 6(a) is a plan view showing the wiring length of the stretchable wiring 2 before it is attached to the mounting body, Figure 6(b) is a plan view showing the wiring length of the stretchable wiring 2 when maximum strain Smax occurs due to the application of tensile force when the structure 101 is attached to the mounting body as shown in Figure 6(c), Figure 6(c) is a plan view showing the wiring length of the stretchable wiring 2 when residual strain Sr occurs after the application of tensile force that causes maximum strain Smax is stopped, and Figure 6(e) is a plan view showing the wiring length of the stretchable wiring 2 immediately after the structure 101 is attached to the mounting body as shown in Figure 6(f).

[0071] Let me explain in more detail. Figure 6(a) shows the initial state of the structure 101, which is a state in which no tensile force has been applied, such as immediately after the structure 101 has been created and completed, and in which no tensile force is currently applied, and the residual strain may be approximately zero. In this initial state, the wiring length of the longest part of the stretchable wiring 2, which is formed in the longitudinal direction (left-right direction in Figure 6) parallel to the width direction or longitudinal direction of the stretchable base material 1, is defined as the initial length L0, and this is used as the reference dimension. In Figure 6, the initial length L0 is the wiring length of any (of interest) wiring portion 2a of the stretchable wiring 2 connecting the upper electrode 8 and the terminal portion 2C, which is parallel to the longitudinal direction of the stretchable base material 1. Hereafter, the wiring portion having this initial length L0 will be referred to as the reference wiring 2a.

[0072] Figure 6(b) shows the structure 101 stretched by applying a tensile force in the longitudinal direction (left-right direction in Figure 6(b)). When attaching the structure 101 to the body to be attached, as shown in Figure 6(c), the structure 101 is stretched, that is, the reference wiring 2a is stretched in the longitudinal direction of the structure 101, and is then placed against the side of the body to be attached (in this case, near the elbow 3A of the arm 3) as shown in Figure 6(c). The length of the reference wiring 2a when the structure 101 is in the state shown in Figure 6(b) is defined as the maximum dimension in the longitudinal direction (left-right direction) (=L0 × (1 + Smax)). Smax is the maximum strain.

[0073] Figure 6(d) shows the residual dimensions (=L0 × (1 + Sr)) of the reference wiring 2a after applying tensile force until it reaches its maximum dimensions and then reducing the tensile force to "0". Here, Sr is the residual strain. Note that the structure 101 in Figure 6(d) is shown with a dashed line because it is not necessary to actually go through the state shown in Figure 6(d), i.e., it is a reference diagram.

[0074] Figure 6(e) shows the length of the reference wiring 2a during installation when the structure 101 is installed as shown in Figure 6(f). As shown in Figure 6(e), the reference wiring 2a is longer than the initial length L0 and shorter than the maximum dimension L0 × (1 + Smax). Also, the reference wiring 2a is longer than the residual dimension L0 × (1 + Sr) and shorter than the maximum dimension L0 × (1 + Smax). In Figure 6(f), the load sensor 9 is installed on the front of the projection of the elbow 3A, and the joint 101a is positioned on the side of the elbow 3A. The reason for positioning the joint 101a on the side of the elbow 3A is that the dimensional change on the side is smaller than the dimensional change on the front of the projection. On the other hand, the load sensor 9 is not limited to being installed on the front of the projection of the elbow 3A, and may be installed in any number necessary at the location where the load is to be determined.

[0075] In the second embodiment, the residual strain Sr is the same as the residual strain Sr in the first embodiment, and is the strain value obtained by performing a tensile test on the stretchable substrate 1 with the reference wiring 2a. In the second embodiment, as in the first embodiment, the length of the left-right reference wiring 2a of the structure 101 of the present invention becomes greater than L0 during wear (for example, when the arm 3 is bent and extended), as shown by the arrow in Figure 2(d), and fluctuates only within a range smaller than L0 × (1 + Smax). Furthermore, the length of the reference wiring 2a takes a value greater than the residual dimension L0 × (1 + Sr), that is, the length of the reference wiring 2a fluctuates only within a range greater than the residual dimension L0 × (1 + Sr) and smaller than the maximum dimension L0 × (1 + Smax).

[0076] Figures 6(c) and 6(f) show examples of the structure 101 being attached so that its back surface is in contact with the human body. In Figure 6(c), the stretchable wiring 2 is represented by a dashed line and solid white, indicating that this is a view of the back surface. In Figure 6(f), the structure 101 is attached to the human body in a cylindrical shape. In this case, the back surface of one end of the structure 101 in the longitudinal direction is joined to the back surface of the other end. Adhesive or hook-and-loop fastener may be used for joining.

[0077] Although Figure 6 does not show the flexible wiring board or protective film, it typically includes the flexible wiring board 4 described above. A protective film 5 may also be provided to cover the surface of the stretchable substrate 1. Alternatively, a protective film may be provided not only on the surface side of the stretchable substrate 1 but also on the back side.

[0078] Figure 7(a) also shows an example where the structure 101 is attached with its back surface facing the human body, and the structure 101 is attached to the human body in a cylindrical shape. In this case, the back surface of one end of the structure 101 in the longitudinal direction is joined to the surface of the other end. Adhesives or hook-and-loop fasteners may be used for joining. In Figure 7(a), the structure 101 does not show a flexible wiring board or protective film, but it usually has the flexible wiring board 4 described above. The structure 101 may also have a protective film 5 covering its surface. Alternatively, the protective film may be present not only on the surface side but also on the back side of the stretchable base material 1.

[0079] Figures 7(b) to 7(d) show examples of how the structure 101 is attached so that its surface is in contact with the human body. In Figures 7(c) and 7(d), the stretchable wiring 2 is represented by a dashed line and solid white fill, indicating a view from the back. In Figure 7(c), the structure 101 is made into a cylindrical shape and attached to the human body. At this time, the surface of one end of the structure 101 in the longitudinal direction is joined to the surface of the other end. Adhesive or hook-and-loop fastener may be used for joining.

[0080] In Figure 7(c), the structure 101 does not show the flexible wiring board or protective film, but it usually has the flexible wiring board 4 described above. The structure 101 may also have a protective film 5. Alternatively, the structure 101 may have a protective film (not shown) not only on the surface but also on the back side of the stretchable substrate 1. In Figure 7(c), the protective film on the front side of the stretchable substrate 1 is effective and important in preventing the stretchable wiring 2 from directly contacting the skin and malfunctioning.

[0081] Figure 7(d) also shows an example where the surface of the structure 101 is in contact with the human body, and the structure 101 is attached to the human body in a cylindrical shape. In this case, the back surface of one end of the structure 101 in the longitudinal direction is joined to the surface of the other end. Adhesive or hook-and-loop fastener may be used for joining. Although the flexible wiring board and protective film are not shown in Figure 7(d), the flexible wiring board 4 described above is usually included. The structure 101 may also have a protective film 5. Alternatively, the structure 101 may have a protective film not only on the surface side but also on the back side of the stretchable base material 1.

[0082] An example of a manufacturing method for the structure 101 shown in Figure 6 or Figure 7 is shown in Figures 8 and 9. In Figure 8, (a') to (d') are cross-sectional views of the AA' section of (a) to (d). Similarly, in Figure 9, (a') to (c') are cross-sectional views of the AA' section of (a) to (c).

[0083] First, a sheet-like stretchable substrate 1 is prepared. However, it is desirable that one side (the back side) of the stretchable substrate 1 has a non-stretchable release film 1R (Figure 8(a), (a')). The stretchable substrate 1 is preferably a material called an elastomer, which has a Young's modulus of 100 kPa or more and 100 MPa or less, stretches with a small tensile force, and tends to return to its original shape when the tension is released. Examples include urethane, epoxy, acrylic, and silicone materials. The non-stretchable release film 1R is preferably a material with a Young's modulus of 100 MPa or more and 10 GPa or less, which deforms only slightly with a small force. Examples include PET, PEN, and PI. When a non-stretchable resin is used as the release film, it is preferable that the surface of the release film has a release layer such as silicone or fluororesin (not shown).

[0084] Next, a lower electrode 6 is formed on the other side (surface) of the stretchable substrate 1, near one end in the longitudinal direction (Figure 8(b), (b')). The lower electrode 6 is preferably a thin film made of a conductive material. Suitable materials for the lower electrode 6 include conductive polymers such as polythiophenes like PEDOT (poly(3,4-ethylenedioxythiophene)), polyaniline, polypyrrole, polyacetylene, poly(p-phenylenevinylene), and poly(p-phenylene sulfide), but metals such as Ag, Al, Au, and Pt may also be used. For the manufacturing method, a dispenser method or inkjet method is used for conductive polymers, and a vapor deposition method or sputtering method is used for metals.

[0085] Next, a ferroelectric layer 7 is formed (Figure 8(c), (c')). Suitable materials for the ferroelectric layer 7 include PVDF (polyvinylidene difluoride), P(VDF-TrFE) i.e., vinylidene difluoride-trifluoroethylene copolymer, polylactic acid, electret, etc. Suitable manufacturing methods include the dispenser method and the inkjet method. The ferroelectric layer 7 is formed on the surface of the stretchable substrate 1 so as to cover a portion of the upper surface of the lower electrode 6.

[0086] Furthermore, the stretchable wiring 2, terminal portion 2C, and upper electrode 8 are formed (Figure 8(d), (d')). The materials for the stretchable wiring 2, terminal portion 2C, and upper electrode 8 are preferably a mixture of elastomer (urethane-based, epoxy-based, acrylic-based, silicone-based, etc.) and metal particles (silver, etc.). Screen printing is preferred as the manufacturing method, but the dispenser method or nozzle printing may also be used. The laminate of the lower electrode 6, ferroelectric layer 7, and upper electrode 8 constitutes the load sensor 9.

[0087] Furthermore, it is preferable to apply the stretchable wiring 2 to a large-area stretchable substrate 1 in multiple directions up to this step, and the stretchable substrate 1 may be separated into individual pieces using a pinnacle die or the like after the stretchable wiring 2 has been formed. A polling process is performed by applying a high voltage to activate the ferroelectric material. The upper electrode 8 is formed extending from a portion of the upper surface of the ferroelectric layer 7 to the upper surface of the stretchable substrate 1. A pair of terminal portions 2C are formed on one longitudinal end of the stretchable substrate 1, and a stretchable wiring 2 is formed to connect the upper electrode 8 to one terminal portion 2C, and a stretchable wiring 2 is formed to connect the lower electrode 6 to the other terminal portion 2C. In Figure 8(d), the stretchable wiring 2 is arranged with its corners bent at approximately right angles so as to be parallel to the longitudinal and width directions of the stretchable substrate 1, but the shape is not limited to this.

[0088] Furthermore, a flexible wiring board 4 is connected to the terminal portion 2C of the stretchable wiring 2 on the surface of the stretchable substrate 1 (Figure 9(a), (a')). The flexible wiring board 4 has conductive wiring (terminal portion) 4B (usually copper) formed on a non-stretchable insulating film 4A (usually polyimide), and a portion is covered with a coverlay (usually polyimide, not shown), while the conductive wiring (terminal portion) 4B not covered with the coverlay is Au plated.

[0089] The flexible wiring board 4 is formed with slits 4S, similar to the flexible wiring board 4 in the first embodiment. The presence of slits 4S between terminal portions 4B means that when the structure 101 is subjected to expansion and contraction in the vertical direction as shown in Figure 9(c), the portion of the expandable substrate 1 facing the terminal portions 4B (i.e., between terminal portions 2C) is primarily responsible for the expansion and contraction. This suppresses expansion and contraction at the connection portion between terminal portions 2C and terminal portions 4B, thereby preventing damage to the connection portion between terminal portions 2C and the flexible wiring board 4. For the connection between the flexible wiring board 4 and the terminal portions 2C, an anisotropic conductive film having conductive particles in the resin is preferred, and among anisotropic conductive films, those containing acrylic resin or thermoplastic resin that can be connected at low temperatures are preferred.

[0090] Next, the adhesive 5A provided on the front side of the stretchable protective film 5 (with a non-stretchable back release film 5R) is applied to cover all or part of the exposed portion of the stretchable wiring 2 on the stretchable substrate 1, and the load sensor 9 (Figure 9(b), (b')). At this time, the joint portion between the flexible wiring board 4 and the terminal portion 2C may also be covered. The protective film 5 can be made of urethane, acrylic, epoxy, or silicone. The back release film 5R can be made of PET, PEN, or PI. The adhesive 5A can be made of urethane, acrylic, epoxy, or silicone.

[0091] Finally, the back release film 1R of the stretchable substrate 1 and the back release film 5R of the protective film 5 are peeled off to complete the structure 101 of the present invention and obtain the initial state of the structure 101 (Figure 9(c), (c')). However, if a protective film is also to be applied to the back surface of the stretchable substrate 1, after peeling off the back release film 1R of the stretchable substrate 1, the adhesive side of the front of the stretchable protective film (with a non-stretchable back release film) is attached to the back surface of the stretchable substrate 1. Then, the back release film 5R of the front protective film 5 and the back release film of the back protective film (not shown) are peeled off to complete the initial state of the structure 101.

[0092] As shown in Figure 6(f), when attaching the structures 101, if hook-and-loop fasteners are used to join the back surfaces of the structures 101, either the back protective film is not provided, or the back release film of the back protective film is peeled off, the hook-and-loop fastener members are adhered to both ends of the back surface, and then the back release film 5R of the front protective film 5 of the stretchable base material 1 is peeled off. As shown in Figure 7(c), when attaching the structures 101, if hook-and-loop fasteners are used to join the surfaces of the structures 101, the back release film 5R of the front protective film 5 is peeled off, the hook-and-loop fastener members are adhered to both longitudinal ends of the front protective film on the surface of the stretchable base material 1, and then the back release film of the protective film on the back of the stretchable base material 1 is peeled off.

[0093] As shown in Figures 7(a) and 7(d), when attaching the structure 101, if hook-and-loop fasteners are used to join the front and back surfaces, the release film on the front surface of one end of the structure 101 is partially peeled off and the hook-and-loop fastener is attached, the release film 5R on the back surface of the other end is peeled off and the hook-and-loop fastener is attached, and then the release film on the front surface is completely peeled off. Alternatively, the release film on the back surface of one end of the structure 101 is partially peeled off and the hook-and-loop fastener is attached, the release film on the front surface of the other end is peeled off and the hook-and-loop fastener is attached, and then the release film on the back surface is completely peeled off.

[0094] In this second embodiment, as in the first embodiment, the loosening of the stretchable base material 1 due to the bending and extending motion of the arm 3 is suppressed, thereby suppressing the deterioration of the reference wiring 2a and suppressing a decrease in the detection accuracy of the load sensor 9. Furthermore, deterioration of the portion of the stretchable wiring 2 parallel to the reference wiring 2a can also be suppressed. In this second embodiment, by applying tensile force to the portion of the expandable wiring 2 that is positioned parallel to the width direction of the structure 101 using the same procedure, deterioration can be suppressed not only for the longitudinal direction of the structure 101 but also for the expandable wiring 2 that is positioned parallel to the width direction.

[0095] [Third Embodiment] Next, a third embodiment of the present invention will be described. An example of a structure 102 according to the third embodiment is shown in Figure 10. The structure 102 in Figures 10(a) to (d) has an expandable wiring 2 and an elongation sensor 10 on an expandable substrate 1. In the third embodiment, the elongation sensor 10 is made of a different material from the expandable wiring 2. The structure 102 in the third embodiment is identical to the structure 102 in the first embodiment except that the material of the elongation sensor 10 is different.

[0096] In Figure 10, Figure 10(a) is a plan view showing the wiring length of the stretchable wiring 2 before tension is applied to the wearer (arm), Figure 10(b) is a plan view showing the wiring length of the stretchable wiring 2 when maximum strain Smax occurs due to the application of tensile force when the structure 102 is attached to the wearer as shown in Figure 10(c), Figure 10(d) is a plan view showing the wiring length of the stretchable wiring 2 when residual strain Sr occurs after the application of tensile force that causes maximum strain Smax is stopped, and Figure 10(e) is a plan view showing the wiring length of the stretchable wiring 2 immediately after being attached to the wearer as shown in Figure 10(f).

[0097] Let me explain in more detail. Figure 10(a) shows the initial state of the structure 102 before applying tensile force, and its wiring length (initial length L0) at this time is used as the reference dimension. Figure 10(b) shows the structure 102 stretched by applying tensile force in its longitudinal direction (left-right direction in Figure 10), and in this state, it is placed against the side of the body to be attached (here, near the elbow 3A of arm 3) as shown in Figure 10(c). This state in Figure 10(b) is the state in which the structure has reached its maximum dimension (=L0 × (1 + Smax)) in the left-right direction (where Smax is the maximum strain). Figure 10(d) shows the residual dimension (=L0 × (1 + Sr)) when the tensile force is reduced to "0" after the expandable wiring 2 has reached its maximum dimension. Here, Sr is the residual strain. Note that in Figure 10(d), the structure 102 is shown with a dashed line because it is not necessary to actually go through the state shown in Figure 10(d), i.e., it is a reference diagram.

[0098] Figure 10(e) shows the wiring length of the expandable wiring 2 of the structure 102 when it is attached to the body as shown in Figure 10(f). This length is longer than the initial length L0 and shorter than the maximum dimension L0 × (1 + Smax). Furthermore, the dimensions during use (during measurement), such as when bending and extending the arm, are longer than the residual dimension L0 × (1 + Sr) and shorter than the maximum dimension L0 × (1 + Smax).

[0099] As shown in Figure 10(f), the structure 102 is installed so that the extension sensor 10 is in front of the projection on the elbow 3A, and the joint 102a is positioned on the side of the elbow 3A. The reason for positioning the joint 102a on the side of the elbow 3A is that the dimensional change of the portion on the side is smaller than the dimensional change in front of the projection. In the third embodiment, as in the first embodiment, the length of the left-right expandable wiring 2 of the structure 102 of the present invention fluctuates only within a range greater than L0 and shorter than L0(1+Smax) during use (for example, when the arm 3 is bent and extended), as indicated by the arrow in Figure 2(d). Furthermore, it fluctuates only within a range longer than the residual dimension L0(1+Sr) and shorter than the maximum dimension L0(1+Smax), that is, within the range from L0(1+Sr) to the maximum dimension L0(1+Smax).

[0100] Figures 10(c) and (f) show examples of the structure 102 being attached so that its back surface is in contact with the human body. In Figure 10(c), the dashed line and solid white area indicate a view of the back surface of the stretchable wiring 2. In Figure 10(f), the structure 102 is attached to the human body in a cylindrical shape. In this case, the back surface of one end of the structure 102 in the longitudinal direction is joined to the back surface of the other end. Adhesive or hook-and-loop fastener may be used for joining. Although Figure 10 does not show the flexible wiring board or protective film, it usually has the flexible wiring board 4 described above. It may also have a protective film 5. Alternatively, the protective film may be on the back surface of the stretchable base material 1 as well as the front surface.

[0101] Figures 11(a) and (b) show examples of how the structure 102 is attached so that its surface is in contact with the human body. In Figure 11(b), the dashed line and solid white representation of the stretchable wiring 2 indicates that this is a view of the back surface. In Figure 11(b), the structure 102 is attached to the human body in a cylindrical shape. At this time, the surface of one end of the structure 102 in the longitudinal direction is joined to the surface of the other end. Adhesive or hook-and-loop fastener may be used for joining.

[0102] Although Figure 11 does not show the flexible wiring board or protective film, it typically includes the flexible wiring board 4 described above. It may also have a protective film 5. Alternatively, the protective film may be provided not only on the surface side but also on the back side of the stretchable substrate 1. In Figure 11(b), providing a protective film on the front side of the stretchable substrate 1 is effective and important in preventing the stretchable wiring 2 from coming into direct contact with human skin and malfunctioning.

[0103] Figures 12 and 13 show an example of a manufacturing method for the structure 102 shown in Figures 10 and 11. In Figure 12, (a) to (d) are plan views, and (a') to (d') are cross-sectional views of (a) to (d) in section AA'. Similarly, in Figure 13, (a) and (b) are plan views, and (a') and (b') are cross-sectional views of (a) and (b) in section AA'.

[0104] First, a sheet-like stretchable substrate 1 is prepared. However, it is desirable to have a non-stretchable release film 1R on the back side (Figure 12(a), (a')). Suitable stretchable substrate 1 is a material called an elastomer, which has a Young's modulus of 100 kPa or more and 100 MPa or less, stretches with a small tensile force, and tends to return to its original state when the tension is released. Examples include urethane, epoxy, acrylic, and silicone materials. Suitable non-stretchable release film 1R is a material with a Young's modulus of 100 MPa or more and 10 GPa or less, which deforms only slightly with a small force. Examples include PET, PEN, and PI. When using a non-stretchable resin as the release film, it is preferable to have a release layer such as silicone or fluororesin (not shown) on the surface.

[0105] Next, an elongation sensor 10 is formed on the surface of the stretchable substrate 1 (Figure 12(b), (b')). The elongation sensor 10 is preferably one whose resistance changes with elongation. Examples of elongation sensors 10 include Ag-containing elastomers, metal-containing elastomers, and carbon particle-containing elastomers.

[0106] Next, the stretchable wiring 2 and terminal portion 2C are formed (Figure 12(c), (c')). It is desirable for the stretchable wiring 2 to have low electrical resistance. However, normally, the electrical resistance of the stretchable wiring 2 increases when stretched and decreases when contracted. By employing a four-wire measurement method, the influence of the resistance of the stretchable wiring 2 is eliminated, and the resistance of the stretch sensor 10 can be measured purely. The material of the stretchable wiring 2 is preferably a mixture of elastomer (urethane, epoxy, acrylic, silicone, etc.) and metal particles (silver, etc.). Screen printing is preferred as the manufacturing method, but the dispenser method or nozzle printing may also be used. Furthermore, it is preferable to apply multiple layers to a large-area stretchable substrate 1 up to this step, and the stretchable substrate 1 may be separated into individual pieces using a pinnacle die or the like after the stretchable wiring 2 is formed.

[0107] Furthermore, a flexible wiring board 4 is connected to the terminal portion 2C of the stretchable wiring 2 on the surface of the stretchable substrate 1 (Figure 12(d), (d')). The flexible wiring board 4 has conductive wiring (terminal portion) 4B (usually copper) formed on a non-stretchable insulating film 4A (usually polyimide), and a portion is covered with a coverlay (usually polyimide, not shown), and the conductive wiring (terminal portion) 4B not covered with the coverlay is gold-plated.

[0108] The flexible wiring board 4 is provided with a slit 4S, similar to the flexible wiring board 4 in the first and second embodiments described above. As mentioned above, it is desirable to provide a slit 4S between the terminal portions 4B of the flexible wiring board 4. The presence of a slit 4S between the terminals allows the structure 102 to be subjected to expansion and contraction forces in the vertical direction as shown in Figure 12(d). The portion of the stretchable base material 1 facing the portion between the terminal portions 4B (i.e., the portion between the 2Cs) is primarily responsible for the expansion and contraction, thereby suppressing expansion and contraction at the connection portion between the terminal portion 4B and the terminal portion 2C, and preventing damage at the connection portion between the terminal portion 4B and the terminal portion 2C. For the connection between the terminal portion 4B and the terminal portion 2C, an anisotropic conductive film having conductive particles in the resin is preferred, and among anisotropic conductive films, those containing an acrylic resin or thermoplastic resin that can be connected at low temperatures are preferred.

[0109] Next, the adhesive 5A provided on the front side of the stretchable protective film 5 (with a non-stretchable back release film 5R) is applied to cover all or part of the exposed portion of the stretchable wiring 2 on the stretchable substrate 1 (Figure 13(a), (a')). At this time, the joint portion between the flexible wiring board 4 and the stretchable wiring 2 may also be covered. The protective film 5 can be made of urethane, acrylic, epoxy, or silicone. The back release film 5R can be made of PET, PEN, or PI. The adhesive 5A can be made of urethane, acrylic, epoxy, or silicone.

[0110] Finally, the back release film 1R of the stretchable substrate 1 and the back release film 5R of the protective film 5 are peeled off to complete the structure 102 of the present invention and obtain the structure 102 in its initial state (Figure 13(b), (b')). However, if a protective film is also applied to the back surface of the stretchable substrate 1, after peeling off the back release film 1R of the stretchable substrate, the adhesive on the front side of the stretchable protective film (with a non-stretchable back release film) is applied to the back surface of the stretchable substrate 1. Then, the back release film 5R of the front protective film 5 and the back release film of the back protective film (not shown) are peeled off to obtain the structure 102 in its initial state.

[0111] When using hook-and-loop fasteners to join the back surfaces of the structures 102 as shown in Figure 10(f), either the back protective film is not provided, or the back release film of the back protective film is peeled off, the hook-and-loop fastener members are adhered to both ends of the back surface, and then the back release film 5R of the protective film on the front side of the stretchable base material 1 is peeled off. As shown in Figure 11(b), when using hook-and-loop fasteners to join the surfaces of the structures 102, peel off the back release film 5R of the front protective film 5, adhere the hook-and-loop fastener members to both longitudinal ends of the surface of the structure 102, and then peel off the back release film of the protective film on the back side of the stretchable base material 1.

[0112] In this third embodiment as well, the loosening of the stretchable base material 1 due to the bending and straightening motion of the arm 3 is suppressed, and the deterioration of the stretchable wiring 2 caused by the loosening is suppressed, thereby suppressing a decrease in the detection accuracy of the stretch sensor 10.

[0113] [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. An example of a structure 103 according to the fourth embodiment is shown in Figure 14. The structure 103 in Figures 14(a) to (d) has an expandable wiring 2 and a sensor 11 on an expandable base material 1. In addition to an elongation sensor and a load sensor, a temperature sensor, an acceleration sensor, etc., can be applied as the sensor 11. Structure 103 is identical to structure 100 in the first embodiment except that the sensor 11 is provided in place of the elongation sensor 2S.

[0114] In Figure 14, Figure 14(a) is a plan view showing the wiring length of the stretchable wiring 2 before it is attached to the mounting body, Figure 14(b) is a plan view showing the wiring length of the stretchable wiring 2 when maximum strain Smax occurs due to the application of tensile force when the structure 103 is attached to the mounting body as shown in Figure 14(c), Figure 14(d) is a plan view showing the wiring length of the stretchable wiring 2 when residual strain Sr occurs after the application of tensile force that causes maximum strain Smax is stopped, and Figure 14(e) is a plan view showing the wiring length of the stretchable wiring 2 immediately after the structure 103 is attached to the mounting body as shown in Figure 14(f).

[0115] Let me explain in more detail. Figure 14(a) shows the structure 103 in its initial state before tensile force is applied, where no tensile force is currently applied and residual strain is approximately zero. The wiring length of the expandable wiring 2 at this time is defined as the initial length L0 and is used as the reference dimension. Figure 14(b) shows the structure 103 stretched by applying a tensile force in its longitudinal direction (left-right direction in Figure 14(b)). In this state, it is placed against the side of the body to be attached (here, near the elbow 3A of arm 3) as shown in Figure 14(c). This state in Figure 14(b) is the state in which the structure has reached its maximum dimension (=L0 × (1 + Smax)) in the left-right direction (where Smax is the maximum strain). Figure 14(d) shows the residual dimension (=L0 × (1 + Sr)) when the tensile force is reduced to "0" after the expandable wiring 2 has reached its maximum dimension. Here, Sr is the residual strain. Note that in Figure 14(d), the structure 103 is shown with a dashed line because it is not actually necessary to go through the state in Figure 14(c), i.e., it is a reference diagram.

[0116] Figure 14(e) shows the dimensions of the expandable wiring 2 of the structure 103 when it is attached as shown in Figure 14(f). It is longer than the initial length L0 and shorter than the maximum dimension L0(1+Smax). Furthermore, even during use when bending and extending the arm, the dimensions of the expandable wiring 2 are longer than the residual dimension L0(1+Sr) and shorter than the maximum dimension L0(1+Smax). As shown in Figure 14(f), the structure 103 is installed so that the sensor 11 is in front of the protrusion of the elbow 3A, and the joint 103a is positioned on the side of the elbow 3A. The joint 102a is positioned on the side of the elbow 3A because the dimensional change in the part on the side is smaller than the dimensional change in the part in front of the protrusion. Note that the installation position of the sensor 11 does not have to be in front of the protrusion of the elbow 3A. Also, multiple sensors 11 may be set.

[0117] In the fourth embodiment, as in the first embodiment, the length of the left-right expandable wiring 2 of the structure 103 of the present invention fluctuates only within a range that is longer than L0, as shown by the arrow in Figure 2(d), that is, longer than the residual dimension L0 × (1 + Sr) and shorter than the maximum dimension L0 × (1 + Smax), during use (for example, when the arm 3 is bent and extended). Figures 14(c) and (f) show examples of the structure 103 being attached so that its back surface is in contact with the human body. In Figure 14(c), the stretchable wiring 2, shown as a dashed line and filled in white, indicates that it is viewed from the back surface. In Figure 14(f), the structure 103 is attached to the human body in a cylindrical shape. In this case, the back surface of one end of the structure 103 in the longitudinal direction is joined to the back surface of the other end. Adhesive or hook-and-loop fastener may be used for joining. Although the flexible wiring board and protective film are not shown in Figure 14, the flexible wiring board 4 described above may be included, or the protective film 5 may be included. Alternatively, a protective film (not shown) may be included not only on the front surface but also on the back surface of the stretchable base material 1.

[0118] Figures 15(a) and (b) show examples of how the structure 103 is attached so that its surface is in contact with the human body. In Figure 15(b), the stretchable wiring 2, represented by a dashed line and solid white, indicates that it is viewed from the back. In Figure 15(b), the structure 103 is attached to the human body in a cylindrical shape. At this time, the surface of one end of the structure 103 in the longitudinal direction is joined to the surface of the other end. Adhesive or hook-and-loop fastener may be used for joining.

[0119] Although Figure 15 does not show the flexible wiring board or protective film, it typically includes the flexible wiring board 4 described above. It may also include a protective film 5. Alternatively, the protective film may be provided not only on the surface side but also on the back side of the stretchable substrate 1. In Figure 15, providing a protective film on the front side of the stretchable substrate 1 is effective and important in preventing the stretchable wiring 2 from directly contacting the skin and malfunctioning.

[0120] Figures 16 and 17 show an example of a manufacturing method for the structure 103 shown in Figure 14 or Figure 15. In Figure 16, (a') to (d') are cross-sectional views of the AA' section of (a) to (d), and similarly in Figure 17, (a') to (b') are cross-sectional views of the AA' section of (a) to (b).

[0121] First, a sheet-like stretchable substrate 1 is prepared. However, it is desirable to have a non-stretchable release film 1R on the back side (Figure 16(a), (a')). Suitable stretchable substrate 1 is a material called an elastomer, which has a Young's modulus of 100 kPa or more and 100 MPa or less, stretches with a small tensile force, and tends to return to its original state when the tension is released. Examples include urethane, epoxy, acrylic, and silicone materials. Suitable non-stretchable release film 1R is a material with a Young's modulus of 100 MPa or more and 10 GPa or less, which deforms only slightly with a small force. Examples include PET, PEN, and PI. When using a non-stretchable resin as the release film, it is preferable to have a release layer such as silicone or fluororesin (not shown) on the surface.

[0122] Next, the stretchable wiring 2 and terminal portion 2C are formed (Figure 16(b), (b')). The material of the stretchable wiring 2 is preferably a mixture of elastomer (urethane, epoxy, acrylic, silicone, etc.) and metal particles (silver, etc.). Screen printing is preferred as the manufacturing method, but the dispenser method or nozzle printing may also be used. Furthermore, it is preferable to apply the stretchable wiring 2 to a large-area stretchable substrate 1 in multiple directions up to this step, and after forming the stretchable wiring 2, the stretchable substrate 1 may be separated into individual pieces using a pinnacle die or the like.

[0123] Next, the sensor 11 is mounted on the surface of the stretchable substrate 1 (Figure 16(c), (c')). The sensor 11 can be various types of sensors, including not only elongation sensors and load sensors, but also temperature sensors, acceleration sensors, and so on.

[0124] Furthermore, a flexible wiring board 4 is connected to the terminal portion 2C of the stretchable wiring 2 on the surface of the stretchable substrate 1 (Figures 16(d), (d')). The flexible wiring board 4 has conductive wiring (terminal portion) 4B (usually copper) formed on a non-stretchable insulating film 4A (usually polyimide), with a portion covered by a coverlay (usually polyimide, not shown), and the terminal portion 4B not covered by the coverlay is gold-plated. It is desirable to provide a slit 4S between the terminal portions 4B. The presence of a slit 4S between the terminal portions 4B allows the stretchable substrate 1 in the portion opposite to the terminal portion 4B (i.e., the portion between the terminal portions 2C) to primarily bear the expansion and contraction force when the structure 103 is subjected to expansion and contraction force in the vertical direction as shown in Figure 16(d), thereby suppressing expansion and contraction within the terminal portion 2C and preventing damage to the connection portion between the flexible wiring board 4 and the stretchable substrate 1. For connecting the flexible wiring board 4 and the stretchable substrate 1, an anisotropic conductive film having conductive particles in the resin is preferred, and among anisotropic conductive films, those containing acrylic resin or thermoplastic resin that can be connected at low temperatures are preferred.

[0125] Next, the adhesive 5A provided on the front side of the stretchable protective film 5 (with a non-stretchable back release film 5R) is applied to cover all or part of the exposed portions of the stretchable wiring 2 on the stretchable substrate 1, and the sensor 11 (Figure 17(a), (a')). At this time, the protective film 5 may also cover the joint portions of the flexible wiring board 4. The protective film 5 can be made of urethane, acrylic, epoxy, or silicone. The back release film 5R can be made of PET, PEN, or PI. The adhesive 5A can be made of urethane, acrylic, epoxy, or silicone.

[0126] Finally, the back release film 1R of the stretchable substrate and the back release film 5R of the protective film are peeled off. This completes the structure of the present invention and gives the initial structure 103 (Figure 17(b), (b')). However, if a protective film is also to be applied to the back surface of the stretchable substrate 1, after peeling off the back release film 1R of the stretchable substrate, the adhesive side of the front of the stretchable protective film (with a non-stretchable back release film) is attached to the back surface of the stretchable substrate 1. Then, the back release film 5R of the front protective film 5 and the back release film of the back protective film (not shown) are peeled off to complete the structure. This completes the structure 103 of the present invention and gives the initial structure.

[0127] As shown in Figure 14(f), when using hook-and-loop fasteners to join the back surfaces of the structures 103, either the back surface protective film is not provided, or the back release film of the back surface protective film is peeled off, the hook-and-loop fastener members are adhered to both ends of the back surface, and then the back release film 5R of the protective film on the front side of the stretchable base material 1 is peeled off. As shown in Figure 15(b), when using hook-and-loop fasteners to join the surfaces of the structures 103, peel off the back release film 5R of the surface protective film, adhere the hook-and-loop fastener members to both longitudinal ends of the surface of the structure 103, and then peel off the back release film of the protective film on the back side of the stretchable base material 1.

[0128] In this fourth embodiment as well, the loosening of the stretchable base material 1 due to the bending and straightening motion of the arm 3 is suppressed, and the deterioration of the stretchable wiring 2 due to the loosening is suppressed, thereby suppressing a decrease in the detection accuracy of the sensor 11. [Examples]

[0129] [Example 1] In the structure 100 of the present invention, as shown in Figure 2, the wiring length of the expandable wiring 2 in use is longer than the initial length L0 and less than or equal to the maximum length L0 × (1 + Smax). Furthermore, the wiring length of the expandable wiring 2 in use is greater than or equal to the residual length L0 × (1 + Sr) and less than or equal to the maximum length L0 × (1 + Smax).

[0130] A typical example of this is shown in Figure 18, where the length of the expandable wiring 2 in use increases or decreases between L0 × (1 + Sr) and L0 × (1 + Smax). On the other hand, a conventional example of this is shown in Figure 23, where the wiring length of the expandable wiring 2 increases or decreases between L0 and L0 × (1 + Smax). As shown in Figure 18, repeated tests were performed using a structure 100 without the stretch sensor 2S in the structure 100 of the first embodiment. Specifically, an epoxy-based stretchable substrate A was used as the stretchable substrate 1, and stretchable wiring B was used as the stretchable wiring 2.

[0131] When the residual strain Sr was calculated at an initial length L0 = 118 mm and maximum strain Smax = 100%, 50%, and 20%, the results were Sr = 12.7%, 7.6%, and 4.6%, respectively (Figure 19). In Figure 19, the horizontal axis represents maximum strain, and the vertical axis represents maximum strain and residual strain. Characteristic line L1 represents maximum strain, and characteristic line L2 represents residual strain. In Figure 19, the main point of the present invention is to stretch and contract the stretchable wiring 2 so that the strain of the stretchable wiring 2 falls within the range between the characteristic line L2 of residual strain and the characteristic line L1 of maximum strain. A repeated test was conducted in which the stretchable wiring 2 was stretched and contracted so that the strain of the stretchable wiring 2 changed in the range of 16% to 132%, and this was repeated 100 times.

[0132] On the other hand, as a conventional example, a repetitive test was conducted in which the stretchable wiring 2 was stretched and compressed so that the strain of the stretchable wiring 2 changed in the range of 0% to 100%, and this was repeated 100 times. Figure 20 shows the resistance values ​​of the stretchable wiring 2 during repeated testing. However, for clarity, only the maximum values ​​of the resistance fluctuations during the back-and-forth test are plotted in Figure 20. In Figure 20, the horizontal axis represents the number of repetitions in the repeated test, and the vertical axis represents the wiring resistance [Ω] of the stretchable wiring 2. Furthermore, characteristic line L3 shows the wiring resistance when the stretchable wiring 2 is stretched so that its strain changes in the range of 16% to 132%, and characteristic line L4 shows the wiring resistance when the stretchable wiring 2 is stretched so that its strain changes in the range of 0% to 100%.

[0133] As shown in Figure 20, there is no significant difference in the resistance value of the wiring up to about 60 repetitions. However, when the allowable resistance value is set to 100 [kΩ], the stretchable wiring reached its allowable value and reached its lifespan at 65 repetitions in conventional examples, but it was confirmed that in the present invention, it reached its allowable value at 75 repetitions, extending its lifespan.

[0134] [Example 2] As shown in Figure 18, repeated tests were performed using a structure 100 without the stretch sensor 2S in the structure 100 of the first embodiment. Specifically, a different epoxy-based stretch substrate C was used as the stretch substrate 1 from that used in [Example 1], and a different stretch wiring D was used as the stretch wiring 2 from that used in [Example 1].

[0135] Then, the residual strain Sr was calculated at an initial length L0 = 118 mm and maximum strain Smax = 100%, 50%, and 20%, and was found to be Sr = 39.7%, 25.6%, and 13.6%, respectively (Figure 21). In Figure 21, the horizontal axis represents maximum strain, and the vertical axis represents maximum strain and residual strain. Characteristic line L5 represents maximum strain, and characteristic line L6 represents residual strain. In Figure 21, the main point of the present invention is to stretch and contract the expandable wiring 2 so that the strain changes between the residual strain characteristic line L6 and the maximum strain characteristic line L5. A repeated test was conducted in which the expandable wiring 2 was stretched and contracted so that the strain of the expandable wiring 2 changed in the ranges of 40% to 100%, 26% to 50%, and 14% to 20%, and this was repeated 100 times.

[0136] On the other hand, as a conventional example, a repetitive test was conducted in which the stretchable wiring 2 was stretched and compressed so that the strain of the stretchable wiring 2 changed in the ranges of 0% to 100%, 0% to 50%, and 0% to 20%, and this was repeated 100 times. Figure 22 shows the ratio of resistance values ​​before and after repeated testing (R100 / R1 = resistance value after repeated testing / resistance value before repeated testing). In the present invention, when the strain of the stretchable wiring 2 was 40%~100%, 26%~50%, and 14%~20%, the ratio of resistance values ​​before and after repeated testing R100 / R1 was "5.6", "2.1", and "1.7", respectively. In contrast, in the conventional example, when the strain of the stretchable wiring 2 was 0%~100%, 0%~50%, and 0%~20%, the ratios were "11.7", "3.5", and "2.6", respectively. In other words, it was confirmed that the present invention can suppress the rate of resistance increase to a smaller extent.

[0137] Furthermore, the present invention can take the following configuration, for example. (1) A structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the one surface or the opposite surface of the stretchable base material is in contact with an object to be attached, and the structure is attached so as to expand and contract in accordance with the movement of the object to be attached, A structure characterized in that, even when the attached object is in a state in which the length of the structure in at least one direction is minimized, the structure is in a state that is more elongated in that one direction than in a state in which no tensile force acts on the structure and residual strain is approximately zero. (2) The unidirectional strain of the stretchable base material while it is being attached is The structure according to (1) above, characterized in that it is always greater than the expected residual strain in the unidirectional direction of the stretchable base material.

[0138] (3) The structure according to (1) or (2) above, characterized in that it includes a sensor disposed on the stretchable substrate and connected to the stretchable wiring. (4) The structure according to (3) above, characterized in that the sensor is an elongation sensor or a load sensor.

[0139] (5) The structure according to any one of (1) to (4) above, characterized in that it includes a stretchable protective film disposed on one surface of the stretchable substrate so as to cover the stretchable wiring. (6) The structure according to any one of (1) to (5) above, characterized in that it includes a flexible wiring board connected to the aforementioned expandable wiring.

[0140] (7) The structure according to (6) above, wherein the flexible wiring board has a plurality of stretchable wirings and a plurality of connecting electrodes connected to each of the stretchable wirings, and has slits between adjacent connecting electrodes. (8) The structure according to any one of (1) to (7) above, characterized in that it is attached in a cylindrical shape by wrapping it around the object to be attached and joining the ends near each other when it is unfolded.

[0141] (9) The structure according to (8) above, characterized in that the surface-jointed portion is attached to the object to be attached in such a manner that it is close to the portion of the object to be attached that is not the circumferential position of the object to be attached where the length of the cylindrical portion of the structure attached to the object to be attached changes the most during attachment. (10) The structure according to any one of (1) to (9) above, characterized in that the stretchable base material is made of epoxy and the unidirectional strain during attachment is 14% or more.

[0142] (11) A method for manufacturing a structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the stretchable base material is attached in contact with an object to be attached, and the structure expands and contracts in accordance with the movement of the object to be attached, A step of designing the initial length L0 of the stretchable base material such that, assuming the maximum dimensions of the stretchable base material that can be taken during the installation process, and the minimum and maximum dimensions of the stretchable base material that can be taken during the installation process, the maximum dimensions of the stretchable base material that can be taken during the installation process are less than or equal to the maximum dimensions of the stretchable base material that can be taken during the installation process, and based on the relationship between the maximum strain and residual strain of the stretchable base material used, the maximum dimensions of the stretchable base material that can be taken during the installation process correspond to "initial length L0 × (1 + maximum strain Smax)", and the minimum dimensions of the stretchable base material that can be taken during the installation process are greater than or equal to "initial length L0 × (1 + residual strain Sr)", Based on the design results in the design process, the process involves printing the stretchable wiring on one side of the stretchable substrate having a non-stretchable film on the opposite side, The process after the printing step involves separating the stretchable substrate into individual pieces of stretchable substrate having the stretchable wiring, The process of removing the non-stretchable film after the individualization process, A method for manufacturing a structure, characterized by having the following features.

[0143] (12) A method for manufacturing the structure according to (11) above, characterized by having a step of forming a sensor on the stretchable substrate immediately before, immediately after, or simultaneously with the step of printing the stretchable wiring. (13) A method for manufacturing the structure according to (11) or (12) above, characterized in that it includes a step of attaching a protective film to at least the surface of the stretchable substrate having the stretchable wiring, which is after the step of printing the stretchable wiring and before the step of removing the non-stretchable film.

[0144] (14) A method for manufacturing the structure according to (13) above, characterized in that immediately before or immediately after the step of applying the protective film, a flexible wiring board is connected to the connecting electrode portion of the stretchable wiring on one side of the stretchable substrate on which the stretchable wiring is formed. (15) A method for using a structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the one surface or the opposite surface of the stretchable base material is in contact with an object to be attached, and the structure is attached so as to expand and contract in accordance with the movement of the object to be attached, The structure is attached to the object to be attached when the length of the structure in at least one direction is minimized, in a state where it is stretched in at least one direction and the strain is greater than the expected residual strain in that direction. A method for using a structure, characterized in that the structure is used in a region where the unidirectional strain of the stretchable base material during attachment is greater than the assumed residual strain. [Industrial applicability]

[0145] This invention is useful for sensors and the like used in biosensing and robotic sensing. [Explanation of symbols]

[0146] 1...Stretchable base material 1R…Release film (non-stretchable) on the back of the stretchable substrate. 2…Stretchable wiring 2C...Terminal portion of expandable wiring 2S…Stretch sensor (same material as stretchable wiring) 2M…Alignment mark for Pinnacle Die 3…arm 3A... Elbow 4… Flexible wiring board 4A...Insulating film 4B...Conductive wiring (terminal section) 4S…Slit 5…Protective film (stretchable) 5A…Adhesive 5R…Release film on the back of the protective film (non-stretchable) 6...Lower electrode 7…Ferroelectric layer 8…Top electrode 9…Load sensor 10... Extension sensor 11...Sensor 20... Pinnacle Dive 21…PET film 22... Rollers of the press machine 100, 101,102,103 structure L0…Initial length Smax…Maximum strain Sr…Residual strain

Claims

1. A structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the one surface or the opposite surface of the stretchable base material is in contact with an object to be attached, and the structure is attached so as to expand and contract in accordance with the movement of the object to be attached, A structure characterized in that, even when the attached object is in a state in which the length of the structure in at least one direction is minimized, the structure is in a state that is more elongated in that one direction than in a state in which no tensile force acts on the structure and residual strain is approximately zero.

2. The unidirectional strain of the stretchable base material while it is being attached is The structure according to claim 1, characterized in that it is always greater than the expected residual strain in the unidirectional direction of the stretchable base material.

3. The structure according to claim 1 or 2, characterized in that it includes a sensor disposed on the stretchable substrate and connected to the stretchable wiring.

4. The structure according to claim 3, characterized in that the sensor is an elongation sensor or a load sensor.

5. The structure according to claim 1 or 2, characterized in that it includes a stretchable protective film disposed on one surface of the stretchable substrate so as to cover the stretchable wiring.

6. The structure according to claim 1 or 2, characterized in that it includes a flexible wiring board connected to the aforementioned expandable wiring.

7. The structure according to claim 6, wherein the flexible wiring board has a plurality of stretchable wirings and a plurality of connecting electrodes connected to each of the stretchable wirings, and has slits between adjacent connecting electrodes.

8. The structure according to claim 1 or 2, characterized in that it is attached in a cylindrical shape by wrapping it around the object to be attached and joining the ends near each other when the object is unfolded.

9. The structure according to claim 8, characterized in that the surface-jointed portion of the structure is attached to the object to be attached in such a manner that it is close to the portion of the object to be attached that is not the circumferential position of the object to be attached where the length of the cylindrical portion of the structure attached to the object to be attached changes the most during attachment.

10. The structure according to claim 1 or 2, characterized in that the stretchable base material is made of epoxy and the unidirectional strain during installation is 14% or more.

11. A method for manufacturing a structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the stretchable base material is attached in contact with an object to be attached, and the structure expands and contracts in accordance with the movement of the object to be attached, Assuming the maximum dimensions of the stretchable base material that can be taken during the installation process, and the minimum and maximum dimensions of the stretchable base material that can be taken during installation, if the maximum dimensions of the stretchable base material that can be taken during installation are less than or equal to the maximum dimensions of the stretchable base material that can be taken during installation, and if, based on the relationship between the maximum strain and residual strain of the stretchable base material used, the maximum dimensions of the stretchable base material that can be taken during installation are "initial length L ０ This corresponds to "×(1 + maximum strain Smax)", and the minimum dimension of the stretchable base material that can be taken during the above-mentioned attachment is "initial length L". ０ The initial length L of the stretchable base material should be greater than or equal to × (1 + residual strain Sr). ０ The process of designing and Based on the design results in the design process, the process involves printing the stretchable wiring on one side of the stretchable substrate having a non-stretchable film on the opposite side, The process after the printing step involves separating the stretchable substrate into individual pieces of stretchable substrate having the stretchable wiring, The process of removing the non-stretchable film after the individualization process, A method for manufacturing a structure, characterized by having the following features.

12. The method for manufacturing the structure according to claim 11, further comprising the step of forming a sensor on the stretchable substrate immediately before, immediately after, or simultaneously with the step of printing the stretchable wiring.

13. A method for manufacturing a structure according to claim 11 or 12, characterized in that the step of attaching a protective film to at least the surface of the stretchable substrate having the stretchable wiring is performed after the step of printing the stretchable wiring and before the step of removing the non-stretchable film.

14. The method for manufacturing the structure according to claim 13, further comprising the step of connecting a flexible wiring board to the connection electrode portion of the stretchable wiring on one side of the stretchable substrate on which the stretchable wiring is formed, immediately before or after the step of applying the protective film.

15. A method for using a structure comprising a sheet-like stretchable base material and stretchable wiring arranged on at least one surface of the stretchable base material, wherein the one surface or the opposite surface of the stretchable base material is in contact with an object to be attached, and the structure is attached so as to expand and contract in accordance with the movement of the object to be attached, The structure is attached to the object to be attached when the length of the structure in at least one direction is minimized, in a state where it is stretched in at least one direction and the strain is greater than the expected residual strain in that direction. A method for using a structure, characterized in that the structure is used in a region where the unidirectional strain of the stretchable base material during attachment is greater than the assumed residual strain.

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