Stretchable device

Abstract

To provide a stretchable device which can stabilize electric connection between connection terminals.SOLUTION: A stretchable device 100 includes: a stretchable substrate 101 having a first resin layer 50, a resin base material 10, an array layer 30 and a second resin layer 60 in an overlapped manner; and a flexible printed board 102 electrically connected to an electric circuit. The resin base material 10 has a plurality of terminal parts 20 arranged so as to be separated from each other. The electric circuit has a plurality of first connection terminals 41 arranged in the terminal parts 20. The flexible printed board 102 has a plurality of second connection terminals 104 facing the first connection terminals 41, an anisotropic conductive resin layer 5 for electrically connecting the first connection terminals 41 and the second connection terminals 104 is provided between the connection terminals, and the first resin layer 50 includes a first surface 51 provided with the resin base material 10, and a dummy terminal part 70 provided on the first surface 51 and arranged around the terminal parts 20.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a stretchable device. [Background technology]

[0002] The stretchable device includes a stretchable substrate having elasticity and flexibility, and a flexible printed circuit board that electrically connects an electric circuit provided on the stretchable substrate to an external device. The stretchable substrate includes an array layer including an electric circuit, a resin substrate that serves as a base material for the array layer, and two resin layers that sandwich the electric circuit and the resin substrate. The resin substrate has body portions arranged in a matrix and hinge portions that connect the body portions to each other. The hinge portions have a meandering shape, as shown in Patent Document 1, for example. When a tensile load acts on the stretchable substrate, the hinge portions become longer in the tensile direction, and the stretchable substrate is extended.

[0003] An example of an electric circuit included in the array layer is a load detection circuit. The load detection circuit has a strain gauge disposed in the hinge section. When the hinge section is deformed, the resistance value of the strain gauge also changes. Then, by detecting the amount of change in the resistance value of the strain gauge, the value of the load acting on the hinge section (stretchable substrate) can be calculated.

[0004] The electric circuit includes, in addition to the load detection circuit, a connection terminal and wiring connecting the connection terminal and the load detection circuit. The connection terminal is electrically connected to the connection terminal of the flexible printed circuit board. In addition, in order to provide the connection terminals and wiring of the electric circuit, the resin base material has a plurality of end portions on which the connection terminals are arranged, and a plurality of connection hinge portions on which the wiring is arranged. The connection terminals of the electric circuit in Patent Document 1 are electrically connected to the connection terminals of the flexible printed circuit board by anisotropic conductive resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-106199 A Summary of the Invention [Problem to be solved by the invention]

[0006] As shown in the above Patent Document 1, the multiple end portions of the resin substrate are separated from each other. In other words, there is a recess between each end portion. Therefore, when an anisotropic conductive resin is disposed between the connection terminals and each of the connection terminals is pressure-bonded to the anisotropic conductive resin, the anisotropic conductive resin tends to move into the recess between each end portion. In other words, the conductive particles contained in the anisotropic conductive resin also tend to move into the recess between each end portion. If the number of conductive particles moving into the recess increases, the electrical connection between the connection terminals becomes unstable, which is not preferable.

[0007] An object of the present invention is to provide a stretchable device that can stabilize the electrical connection between connection terminals. [Means for solving the problem]

[0008] A stretchable device according to one embodiment of the present disclosure includes a stretchable substrate having a first resin layer, a resin base material, an array layer, and a second resin layer stacked in order, and a flexible printed circuit board electrically connected to an electric circuit included in the array layer. The resin base material has a plurality of end portions arranged at a distance from each other. The electric circuit has a plurality of first connection terminals arranged at the end portions. The flexible printed circuit board has a plurality of second connection terminals facing the first connection terminals. An anisotropic conductive resin layer is provided between the first connection terminals and the second connection terminals, electrically connecting the first connection terminals and the second connection terminals. The first resin layer includes a first surface on which the resin base material is provided, and a dummy end portion provided on the first surface and arranged around the end portion. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a stretchable device according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a cross section of the stretchable substrate according to the embodiment, and more specifically, a cross section taken along line II-II in FIG. [Diagram 3] FIG. 3 is a plan view of the resin base material disposed on the first surface of the first resin layer in the first embodiment, viewed from the first thickness direction. [Figure 4] FIG. 4 is an enlarged view of the body portion and the hinge portion of the first embodiment. [Diagram 5] FIG. 5 is an enlarged view of the body portion and the hinge portion to which a tensile load is applied in the first embodiment. [Figure 6] FIG. 6 is a circuit diagram of an electric circuit included in the array layer of the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a plan view of the second embodiment with a part of the anisotropic conductive resin layer removed, as viewed from the first thickness direction. [Figure 9] FIG. 9 is a cross-sectional view of the stretchable device, specifically, a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 10 is a plan view of the end portion and the anisotropic conductive resin layer of the first modification example viewed from the first thickness direction. [Figure 11] FIG. 11 is a plan view of the end portion and the dummy end portion of the third embodiment viewed from the first thickness direction. [Figure 12] FIG. 12 is a plan view of the end portion and the dummy end portion of the fourth embodiment viewed from the first thickness direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The form (embodiment) for implementing the stretchable device of the present disclosure will be described in detail with reference to the drawings. The invention of the present disclosure is not limited to the contents described in the following embodiments. In addition, the components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined. Note that the disclosure is merely an example, and those that a person skilled in the art can easily imagine appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present invention. In order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment, but they are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, the same symbols are used for components similar to those described above with respect to the previous figures, and detailed explanations may be omitted as appropriate.

[0011] Furthermore, in this specification and the claims, when expressing an aspect of arranging another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both the case where another structure is arranged directly on top of a certain structure so as to be in contact with the certain structure, and the case where another structure is arranged above a certain structure via yet another structure.

[0012] (Embodiment 1) Fig. 1 is a schematic diagram of a stretchable device according to an embodiment. As shown in Fig. 1, the stretchable device 100 includes a stretchable substrate 101 and a flexible printed circuit board 102. The stretchable substrate 101 and the flexible printed circuit board 102 are each formed in a flat plate shape. The stretchable substrate 101 has a front surface 1 and a back surface 2 (not shown in Fig. 1; see Fig. 2) that face in opposite directions.

[0013] The stretchable substrate 101 and the flexible printed circuit board 102 are formed to have a rectangular (quadrilateral) shape in plan view. One end 102a of the flexible printed circuit board 102 is bonded to the stretchable substrate 101 by an anisotropic conductive resin layer 5 (see FIG. 7). As a result, the stretchable device 100 is long in the direction in which the stretchable substrate 101 and the flexible printed circuit board 102 are arranged.

[0014] Hereinafter, the direction parallel to the surface 1 and in which the stretchable substrate 101 and the flexible printed circuit board 102 are arranged will be referred to as the longitudinal direction. Furthermore, with regard to the longitudinal direction, the direction in which the stretchable substrate 101 is arranged as viewed from the flexible printed circuit board 102 will be referred to as the first longitudinal direction X1, and the direction opposite to the first longitudinal direction X1 will be referred to as the second longitudinal direction X2. Furthermore, the direction parallel to the surface 1 and intersecting with the longitudinal direction will be referred to as the intersecting direction.

[0015] Fig. 2 is a schematic cross-sectional view of the stretchable substrate according to the embodiment, specifically, a cross-sectional view taken along line II-II in Fig. 1. As shown in Fig. 2, the stretchable substrate 101 includes a first resin layer 50, a resin base material 10, an array layer 30, and a second resin layer 60, which are laminated in this order.

[0016] Hereinafter, the direction in which the first resin layer 50, the resin substrate 10, the array layer 30, and the second resin layer 60 are stacked is referred to as the thickness direction. In addition, with respect to the thickness direction, the direction in which the second resin layer 60 is arranged as viewed from the first resin layer 50 is referred to as the first thickness direction Z1, and the opposite direction to the first thickness direction Z1 is referred to as the second thickness direction Z2. Viewing the stretchable substrate 101 from the first thickness direction Z1 is referred to as a planar view. In addition, with respect to the crossing direction, when the stretchable substrate 101 is viewed in a planar view, the direction in which the right hand is arranged is referred to as the first crossing direction Y1, and the direction in which the left hand is arranged is referred to as the second crossing direction Y2.

[0017] The first resin layer 50 and the second resin layer 60 are formed of a resin and have insulating properties, elasticity, and flexibility. An example of a resin used as the first resin layer 50 and the second resin layer 60 is polyimide. Note that the first resin layer 50 and the second resin layer 60 of the present disclosure are not limited to polyimide, and may be an acrylic resin, an epoxy resin, a urethane resin, or the like, and are not particularly limited.

[0018] The first resin layer 50 and the second resin layer 60 extend in the longitudinal direction and the intersecting direction, respectively, and are formed in a plate shape. The surface of the first resin layer 50 in the second thickness direction Z2 constitutes the back surface 2 of the stretchable substrate 101. The first resin layer 50 has a first surface 51 facing the first thickness direction Z1. The resin base material 10 is laminated on the first surface 51.

[0019] The surface of the second resin layer 60 in the first thickness direction Z1 constitutes the surface 1 of the stretchable substrate 101. The surface 61 of the second resin layer 60 in the second thickness direction Z2 covers the array layer 30 from the first thickness direction Z1. At the longitudinal end and the intersecting end of the second resin layer 60, a frame portion 62 is provided that protrudes in the second thickness direction Z2 beyond the surface 61. The frame portion 62 is annular in a plan view and surrounds the outer periphery of the resin substrate 10 and the array layer 30. The surface of the frame portion 62 in the second thickness direction is bonded to the first surface 51 of the first resin layer 50. Thus, the first resin layer 50 and the second resin layer 60 cooperate with each other to form a housing that accommodates the resin substrate 10 and the array layer 30.

[0020] Fig. 3 is a plan view of the resin base material arranged on the first surface of the first resin layer in the first embodiment, viewed from the first thickness direction. In Fig. 3, the resin base material 10 is hatched to make it easier to see. The resin base material 10 is bonded to the first surface 51 of the first resin layer 50. The resin base material 10 has elasticity, flexibility, and insulating properties. The resin base material 10 is formed from a resin material such as polyimide.

[0021] The resin base material 10 includes a plurality of body portions 11, a plurality of hinge portions 12 extending in a meandering manner, a plurality of end portions 20 each having a rectangular shape in a plan view, and a connecting hinge portion 21 extending in a meandering manner from the end portions 20. The end portions 20 and the connecting hinge portion 21 are disposed at the end portion of the first surface 51 in the second longitudinal direction X2 (see the area surrounded by the dashed line A in FIG. 1). On the other hand, the body portion 11 and the hinge portion 12 are disposed on the first surface 51 from the end portion of the first surface 51 in the second longitudinal direction X2 to the first longitudinal direction X1 (see the area surrounded by the dashed line B in FIG. 1).

[0022] 4 is an enlarged view of the body part and the hinge part of the first embodiment. The body part 11 has a quadrangular (square) shape in a plan view. The body part 11 is arranged so that four corners point in a direction intersecting the longitudinal direction. The multiple body parts 11 are arranged in a direction intersecting the longitudinal direction and are spaced apart from each other. Note that the shape of the body part 11 in the present disclosure in a plan view is not limited to a quadrangular shape, and may be a circular shape or another polygonal shape.

[0023] 3, the hinge portion 12 has a vertical hinge portion 12A extending in the longitudinal direction and a horizontal hinge portion 12B extending in the intersecting direction. When the vertical hinge portion 12A is rotated by 90° in a plan view, it has the same shape as the horizontal hinge portion 12B. Therefore, in the following description of the hinge portion 12, the vertical hinge portion 12A will be described as a representative example, and a description of the horizontal hinge portion 12B will be omitted.

[0024] As shown in Fig. 4, the vertical hinge portion 12A has four bent portions 13 and extends in a serpentine manner in the longitudinal direction. Each bent portion 13 in this embodiment is formed in an arc shape. Note that the bent portions of the present disclosure may be formed in an angular shape instead of an arc shape. The number of bent portions is not limited to four.

[0025] The four bent portions 13 are a first arc portion 14, a second arc portion 15, a third arc portion 16, and a fourth arc portion 17, which are arranged in this order from the second longitudinal direction X2. The first arc portion 14 and the fourth arc portion 17 are quadrant-shaped and bent by 90 degrees. The second arc portion 15 and the third arc portion 16 are semicircular-shaped and bent by 180 degrees.

[0026] FIG. 5 is an enlarged view of the body and hinge parts to which a tensile load is applied in the first embodiment. As shown in FIG. 5, when a tensile load in the longitudinal direction (see arrow C in FIG. 5) is applied to the vertical hinge part 12A, the first arc part 14, the second arc part 15, the third arc part 16, and the fourth arc part 17 are deformed so that their curvatures become smaller. As a result, the distance from one end to the other end of the vertical hinge part 12A becomes larger, and the body parts 11 are separated from each other. In addition, when a compressive load in the longitudinal direction (not shown) is applied to the vertical hinge part 12A, the first arc part 14, the second arc part 15, the third arc part 16, and the fourth arc part 17 are deformed so that their curvatures become larger. As a result, the distance from one end to the other end of the vertical hinge part 12A becomes smaller, and the body parts 11 are closer to each other.

[0027] 3, a portion surrounded by the four hinge portions 12 arranged in a ring shape (square shape) forms a lightening portion 19 that penetrates the resin base material 10 in the thickness direction. In other words, the resin base material 10 has a plurality of lightening portions 19.

[0028] 2, the cutout portion 19 is filled with the second resin layer 60. Therefore, the stretchable substrate 101 has low rigidity in the area overlapping with the cutout portion 19, and has elasticity and flexibility (stretchability). Therefore, when a load acts on the stretchable substrate 101, the hinge portion 12 deforms. Also, the deformation of the body portion 11 is small, and damage to the functional element (transistor 36 in this embodiment) stacked on the body portion 11 is suppressed.

[0029] Although the cutout portion 19 in the present embodiment is filled with the second resin layer 60, in the present disclosure, it may be filled with the first resin layer 50. Alternatively, the cutout portion 19 may be filled with both the first resin layer 50 and the second resin layer 60. Alternatively, the cutout portion 19 may be filled with a resin other than the first resin layer 50 and the second resin layer 60. Alternatively, nothing may be disposed in the cutout portion 19, and the cutout portion 19 may be left as a space.

[0030] As shown in Fig. 3, the end portion 20 is formed in a quadrangle shape in a plan view and has four sides. The end portion 20 is arranged so that the four sides face the longitudinal direction and the intersecting direction. The multiple end portions 20 are arranged at equal intervals in the intersecting direction.

[0031] The connecting hinge part 21 extends in the longitudinal direction. An end part of the connecting hinge part 21 in the first longitudinal direction X1 is connected to the body part 11. An end part of the connecting hinge part 21 in the second longitudinal direction X2 is connected to the end part 20. The connecting hinge part 21 has a plurality of bent parts 21a, similar to the hinge part 12, and extends in a meandering manner in the longitudinal direction.

[0032] The spaces between the connecting hinge parts 21 are hollowed out parts 19, which are filled with the second resin layer 60. Therefore, when a load is applied to the stretchable substrate 101, the connecting hinge parts 21 are also deformed. That is, the end parts of the stretchable substrate 101 in the second longitudinal direction X2 (see the area surrounded by the dashed line A in FIG. 1) also have elasticity and flexibility.

[0033] As shown in FIG. 2, the array layer 30 is provided on the surface of the resin base material 10 in the first thickness direction Z1. The array layer 30 has a plurality of insulating layers (not shown) laminated in the thickness direction, and an electric circuit whose insulation from the outside is ensured by the plurality of insulating layers. The electric circuit of this embodiment includes a load detection circuit 31 (see FIG. 6) and a connection wiring 40 (see FIG. 3) that transmits the result of the load detection circuit 31 to an external device. As shown in FIG. 3, the connection wiring 40 is provided in the end portion 20 and the connection hinge portion 21. That is, the connection wiring 40 is disposed at the end of the stretchable substrate 101 in the second longitudinal direction X2 (see the area surrounded by the dashed line A in FIG. 1). The load detection circuit 31 is provided in the body portion 11 and the hinge portion 12. Therefore, the load detection circuit 31 is disposed in the first longitudinal direction X1 from the end of the stretchable substrate 101 in the second longitudinal direction X2 (see the area surrounded by the dashed line B in FIG. 1).

[0034] Fig. 6 is a circuit diagram of an electric circuit included in the array layer of embodiment 1. As shown in Fig. 6, the load detection circuit 31 includes a strain gauge 32, a gate line 33, a signal line 34, a power supply line 35, a transistor 36, a gate line driving circuit 37 (see Fig. 1), a signal line selection circuit 38 (see Fig. 1), a power supply line selection circuit 39 (see Fig. 1), and a driving IC 90 (see Fig. 1).

[0035] 3, the strain gauge 32 is disposed at the vertical hinge portion 12A and extends along the vertical hinge portion 12A. Therefore, when the vertical hinge portion 12A is deformed, the strain gauge 32 is also deformed, and the resistance value of the strain gauge 32 changes. Note that, although the present embodiment shows an example in which the strain gauge 32 is disposed at the vertical hinge portion 12A, the present disclosure also relates to the strain gauge 32 being disposed at the horizontal hinge portion 12B.

[0036] Also, the strain gauges 32 are not arranged at all the vertical hinge parts 12A. To explain in detail, the strain gauges 32 are not arranged at the vertical hinge parts 12A arranged on both sides in the intersecting direction among the multiple vertical hinge parts 12A (see the area surrounded by the dashed line B1 in FIG. 1). Also, the strain gauges 32 are not arranged at the vertical hinge parts 12A arranged at the end of the second longitudinal direction X2 among the multiple vertical hinge parts 12A (see the area surrounded by the dashed lines B2 and B3 in FIG. 1). Therefore, the strain gauges 32 are arranged only at the vertical hinge parts 12A arranged in the area surrounded by the dashed line B4 in FIG. 1. Hereinafter, the area where the strain gauges 32 are arranged is referred to as the detection area B4.

[0037] 3, the gate line 33 extends in the cross direction in the detection area B4 by being disposed across the horizontal hinge parts 12B and the body parts 11. The signal line 34 and the power supply line 35 extend in the longitudinal direction in the detection area B4 by being disposed across the vertical hinge parts 12A and the body parts 11.

[0038] The transistor 36 is disposed in each body portion 11 disposed in the detection region B4. As shown in Fig. 6, the gate electrode of the transistor 36 is connected to the gate line 33. The drain electrode of the transistor 36 is connected to the power supply line 35. The source electrode of the transistor 36 is connected to the signal line 34 via the strain gauge 32.

[0039] The gate line driving circuit 37 is a circuit that drives the multiple gate lines 33 based on a control signal from a driving IC (Integrated Circuit) 90. The gate line driving circuit 37 is arranged in the multiple body parts 11 and the multiple hinge parts 12 that are arranged on both sides in the intersecting direction among the multiple body parts 11 and the multiple hinge parts 12 (see the area surrounded by the dashed line B1 in FIG. 1).

[0040] The signal line selection circuit 38 is a switch circuit that sequentially or simultaneously selects the multiple signal lines 34 based on a control signal from the drive IC 90. As shown in Fig. 1, the signal line selection circuit 38 is arranged in the multiple body parts 11 and the multiple hinge parts 12 that are arranged at the ends in the second longitudinal direction X2 (see the area surrounded by the dashed line B2 in Fig. 1) among the multiple body parts 11 and the multiple hinge parts 12.

[0041] The power supply line selection circuit 39 is a switch circuit that sequentially or simultaneously selects a plurality of power supply lines based on a control signal from the driving IC 90. As shown in Fig. 1, the power supply line selection circuit 39 is disposed in the plurality of body parts 11 and the plurality of hinge parts 12 that are disposed at the end in the second longitudinal direction X2 (see the area surrounded by the dashed line B3 in Fig. 1) among the plurality of body parts 11 and the plurality of hinge parts 12.

[0042] The driving IC 90 is a control device that sends various signals to the gate line driving circuit 37, the signal line selection circuit 38, and the power supply line selection circuit 39 to drive each of the gate line driving circuit 37, the signal line selection circuit 38, and the power supply line selection circuit 39. In this embodiment, the driving IC 90 is provided on the resin base material 10 of the stretchable substrate 101. In detail, the driving IC 90 is disposed in one of the body parts 11 (see FIG. 1) that is located in the most second longitudinal direction X2 and in the first intersecting direction Y1 among the plurality of body parts 11. In addition, the body part 11 in which the driving IC 90 is provided is formed larger in plan view than the other body parts 11. In the present disclosure, the position of the driving IC 90 is not limited to the position shown in the first embodiment. In addition, the driving IC 90 may not be mounted on the stretchable substrate 101 but may be provided in an external device.

[0043] An operation example of the load detection circuit 31 will be described. As shown in Fig. 6, when one gate line 33 selected by the gate line drive circuit 37 is driven, multiple transistors 36 in the intersecting direction connected to the gate line 33 are closed. Also, a signal (e.g., a voltage value) is sent to the strain gauge 32 from one or more power supply lines 35 selected by the power supply line selection circuit 39 via the transistors 36.

[0044] When the vertical hinge portion 12A is not deformed, the voltage value of the signal flowing through the strain gauge 32 is a predetermined value. On the other hand, when the vertical hinge portion 12A is deformed, the resistance value of the strain gauge 32 changes. In other words, the signal flowing through the strain gauge 32 indicates a voltage value different from the predetermined value. The signal (detection result) output from the strain gauge 32 flows to the signal line 34. Then, the signal (detection result) is sent from the signal line 34 selected by the signal line selection circuit 38 to the connection wiring 40 (see FIG. 3).

[0045] 3, the connection wiring 40 includes a plurality of first connection terminals 41 arranged on the end portion 20 and a plurality of wirings 42 arranged on the connection hinge portion 21. The first connection terminal 41 is formed in a rectangular shape in a plan view. Note that the first connection terminal 41 in this embodiment is smaller than the end portion 20 in a plan view, and the end portion 20 is exposed from the periphery of the first connection terminal 41, but in the present disclosure, the first connection terminal 41 and the end portion 20 may be the same size.

[0046] The wiring 42 extends in the longitudinal direction. An end of the wiring 42 in the first longitudinal direction X1 is connected to the load detection circuit 31. An end of the wiring 42 in the second longitudinal direction X2 is connected to the first connection terminal 41.

[0047] 7 is a cross-sectional view taken along line VII-VII in FIG. 1. As shown in FIG. 7, an anisotropic conductive resin layer 5 is provided in the first thickness direction Z1 of the first connection terminal 41. The anisotropic conductive resin layer 5 is a resin having conductive fine particles (hereinafter referred to as conductive particles 6) dispersed therein. As shown in FIG. 3, the length L of the anisotropic conductive resin layer 5 in the planar direction is longer than the lengths of the first connection terminal 41 and the end portion 20 in the planar direction. Therefore, the anisotropic conductive resin layer 5 bulges out from the end portion 20 in the first longitudinal direction X1 and the second longitudinal direction X2, and is bonded to the first surface 51 of the first resin layer 50.

[0048] Moreover, the anisotropic conductive resin layer 5 extends in the intersecting direction. An end of the anisotropic conductive resin layer 5 in the first intersecting direction Y1 extends further in the first intersecting direction Y1 than the first connection terminal 41A, which is the most distant from the first connection terminals 41 in the first intersecting direction Y1. An end of the anisotropic conductive resin layer 5 in the second intersecting direction Y2 extends further in the second intersecting direction Y2 than the first connection terminal 41B, which is the most distant from the first connection terminals 41 in the second intersecting direction Y2. Thus, the anisotropic conductive resin layer 5 is disposed across each of the first connection terminals 41, each of the end portions 20, and the periphery of each of the end portions 20 (the first surface 51 of the first resin layer 50).

[0049] The flexible printed circuit board 102 is a connection component for electrically connecting the stretchable device 100 to an external device. As shown in Fig. 1, the flexible printed circuit board 102 is provided with a second connection terminal 104 disposed on one end 102a of the flexible printed circuit board 102, and a wiring portion 105 extending from the second connection terminal 104 in a second longitudinal direction X2.

[0050] 7, one end 102a of the flexible printed circuit board 102 is disposed between the anisotropic conductive resin layer 5 and the second resin layer 60, and is bonded to both the anisotropic conductive resin layer 5 and the second resin layer 60. The second connection terminal 104 is provided on a surface of the flexible printed circuit board 102 in the second thickness direction Z2, and faces the first connection terminal 41.

[0051] In addition, in the method of forming the anisotropic conductive resin layer 5 of this embodiment, the anisotropic conductive resin layer 5 is applied to each of the first connection terminals 41, each end portion 20, and the periphery of each end portion 20 (the first surface 51 of the first resin layer 50) while the resin of the anisotropic conductive resin layer 5 is in a molten state. Next, the flexible printed circuit board 102 is placed on the first thickness direction Z1 of the anisotropic conductive resin layer 5, and the flexible printed circuit board 102 is pressed in the second thickness direction Z2. As a result, each of the first connection terminals 41, each end portion 20, the periphery of each end portion 20 (the first surface 51 of the first resin layer 50), and the flexible printed circuit board 102 (including the second connection terminal 104) are pressure-bonded to the anisotropic conductive resin layer 5. Then, the resin is cured to form the anisotropic conductive resin layer 5.

[0052] When the flexible printed circuit board 102 is pressed (pressed), the conductive particles 6 are crushed between the first connection terminal 41 and the second connection terminal 104. The crushed conductive particles 6 come into contact with each other and form a conductive path in the thickness direction. The first connection terminal 41 and the second connection terminal 104 are electrically connected by the conductive particles 6.

[0053] As shown in Figs. 3 and 7, a dummy end portion 70 is provided on the first surface 51 of the first resin layer 50. The dummy end portion 70 is arranged around the end portion 20. The dummy end portion 70 is formed of a resin such as polyimide, an inorganic material, or an organic material. The dummy end portion 70 of the first embodiment has a rectangular first dummy end portion 71 arranged between the end portions 20. The size H1 in the thickness direction of the first dummy end portion 71 (see Fig. 7) is the same as that of the end portion 20.

[0054] If the dummy end portion 70 were not present, the space between the end portions 20 would be a recess with the first surface 51 as the bottom surface. Therefore, when the flexible printed circuit board 102 is pressure-bonded to the anisotropic conductive resin layer 5, the anisotropic conductive resin layer 5 would easily move into the recess between the end portions 20 (see arrow D in FIG. 7).

[0055] According to the above-mentioned embodiment 1, the gaps between the end portions 20 are filled with the first dummy end portions 71. When the flexible printed circuit board 102 is pressure-bonded to the anisotropic conductive resin layer 5, the anisotropic conductive resin layer 5 is unlikely to move between the end portions 20. In other words, the conductive particles 6 contained in the anisotropic conductive resin layer 5 are prevented from moving between the end portions 20. This prevents the conductive particles 6 electrically connecting the first connection terminal 41 and the second connection terminal 104 from being reduced. This stabilizes the electrical connection between the first connection terminal 41 and the second connection terminal 104.

[0056] As shown in FIG. 7, the first dummy end portion 71 of the first embodiment is separated from the end portion 20, and a gap is provided between the end portion 20 and the first dummy end portion 71. The size H2 of the gap between the first dummy end portion 71 and the end portion 20 is smaller than the diameter of the conductive particle 6. This makes it difficult for the conductive particle 6 to move between the first dummy end portion 71 and the end portion 20. The diameter of the conductive particle 6 is generally 3 μm. Therefore, it is preferable that the gap between the first dummy end portion 71 and the end portion 20 is less than 3 μm.

[0057] Although the first embodiment has been described above, the present disclosure is not limited to the example of the first embodiment. For example, the size H1 in the thickness direction of the dummy end portion 70 may be larger or smaller than the end portion 20, and is not particularly limited. Next, other embodiments will be described. In addition, the following description will focus on the differences from the first embodiment.

[0058] (Embodiment 2) FIG. 8 is a plan view of the state in which a part of the anisotropic conductive resin layer in the second embodiment is removed, viewed from the first thickness direction. FIG. 9 is a cross-sectional view of the stretchable device, specifically, a cross-sectional view taken along the line IX-IX in FIG. 8. As shown in FIGS. 8 and 9, the stretchable substrate 101A of the stretchable device 100A in the second embodiment is different from that of the first embodiment in that it is disposed only on the first connection terminal 41 (not shown in FIG. 8; see FIG. 9) and the first thickness direction Z1 of the end portion 20, and is not disposed around the end portion 20 (the first surface 51 of the first resin layer 50). That is, the anisotropic conductive resin layer 5A in the second embodiment is composed of divided anisotropic conductive resin layers 7 divided into a plurality of parts. In addition, in order to make the divided anisotropic conductive resin layers 7 in FIG. 8 easier to see, the outer periphery of the divided anisotropic conductive resin layers 7 is illustrated as being smaller than the outer periphery of the end portion 20.

[0059] In the method of forming the anisotropic conductive resin layer 5A of the second embodiment, a sheet-like anisotropic conductive resin in which the resin is hardened is laminated on each of the first connection terminals 41, each end portion 20, and the periphery of each end portion 20 (first surface 51 of the first resin layer 50). This sheet-like anisotropic conductive resin has the same size as the anisotropic conductive resin layer 5 of the first embodiment (see FIG. 3). Next, of the sheet-like anisotropic conductive resin, a portion that overlaps with the periphery of the end portion 20 (first surface of the first resin layer) in the thickness direction is removed, for example, by a laser. As a result, the sheet-like anisotropic conductive resin is divided and placed only on the first connection terminals 41 and the end portions 20.

[0060] Next, the anisotropic conductive resin is melted, and the flexible printed circuit board 102 is pressure-bonded from the first thickness direction Z1 of the anisotropic conductive resin. The resin is then cured to form a plurality of divided anisotropic conductive resin layers 7. When the flexible printed circuit board 102 is pressure-bonded, the conductive particles 6 are crushed between the first connection terminal 41 and the second connection terminal 104. The crushed conductive particles 6 come into contact with each other and form a conductive path in the thickness direction. This electrically connects the first connection terminal 41 and the second connection terminal 104.

[0061] As described above, in the second embodiment, when the flexible printed circuit board 102 is pressure-bonded to the anisotropic conductive resin layer 5A, the anisotropic conductive resin layer 5A is crushed in the second thickness direction Z2. A part of the anisotropic conductive resin layer 5A flows from the first connection terminal 41 and the end portion 20 to between the end portions 20 (see arrow E in FIG. 9). However, since the space between the end portions 20 is filled with the dummy end portion 70 (first dummy end portion 71), a part of the anisotropic conductive resin layer 5A is unlikely to move between the end portions 20. Therefore, even in the second embodiment, the conductive particles 6 electrically connecting the first connection terminal 41 and the second connection terminal 104 are prevented from being reduced.

[0062] FIG. 10 is a plan view of the end portion and the anisotropic conductive resin layer of the first modification example viewed from the first thickness direction. In the second embodiment, the anisotropic conductive resin layer 5A (multiple divided anisotropic conductive resin layers 7) is formed by removing a part of the sheet-like anisotropic conductive resin with a laser or the like, but the present disclosure is not limited thereto. For example, as shown in FIG. 10, the anisotropic conductive resin layer 5B of the first modification example includes multiple divided anisotropic conductive resin layers 7 and an extension portion 8 that connects the divided anisotropic conductive resin layers 7 to each other before being placed on the first connection terminal 41 and the end portion 20. When the flexible printed circuit board 102 is pressure-bonded to the divided anisotropic conductive resin layer 7, the extension portion 8 is not crushed by the flexible printed circuit board 102. Therefore, the conductive particles 6 included in the extension portion 8 are separated from each other and do not form a conductive path. According to the anisotropic conductive resin layer 5B of the first modification example, a process of removing with a laser or the like is not required.

[0063] (Embodiment 3) 11 is a plan view of the end portion and the dummy end portion of the embodiment 3 viewed from the first thickness direction. A stretchable substrate 101C of a stretchable device 100C of the embodiment 3 is different from that of the embodiment 1 in that it has a dummy end portion 70C instead of the dummy end portion 70A.

[0064] The dummy end portion 70C includes a first dummy end portion 71 between the end portions, a second dummy end portion 72 arranged in the second longitudinal direction X2 (the other longitudinal direction) relative to the end portion, and a third dummy end portion 73 arranged on the outermost side in the cross direction. The second dummy end portion 72 can suppress the anisotropic conductive resin layer 5 overlapping the first connection terminal 41 and the end portion 20 from flowing (moving) toward the second longitudinal direction X2.

[0065] The third dummy end portion 73 has a third dummy end portion 73A arranged in the first cross direction Y1 of the end portion 20A arranged closest to the first cross direction Y1 among the multiple end portions, and a third dummy end portion 73B arranged in the second cross direction Y2 of the end portion 20B arranged closest to the second cross direction Y2. The third dummy end portion 73A can suppress the anisotropic conductive resin layer 5 laminated on the first connection terminal 41A arranged closest to the first cross direction Y1 and the end portion 20A from flowing (moving) toward the first cross direction Y1. The third dummy end portion 73B can suppress the anisotropic conductive resin layer 5 laminated on the first connection terminal 41B arranged closest to the second cross direction Y2 and the end portion 20B from flowing (moving) toward the second cross direction Y2.

[0066] As described above, according to the third embodiment, there are more conductive particles between the first connection terminal 41 and the second connection terminal 104 than in the first and second embodiments. Therefore, the electrical connection between the first connection terminal 41 and the second connection terminal 104 is more stable.

[0067] In the above-mentioned embodiment and modified example, an example in which a plurality of terminal parts 20 are arranged in the cross direction is given and described, but the present disclosure is not limited thereto. In the following embodiment 4, an example in which the arrangement of the terminal parts 20 is changed will be described.

[0068] (Embodiment 4) 12 is a plan view of the end portion and the dummy end portion of the fourth embodiment as viewed from the first thickness direction. The stretchable substrate 101D of the stretchable device 100D of the fourth embodiment differs from that of the first embodiment in that a plurality of end portions 20D are arranged shifted in the longitudinal direction. The end portion 20D has a plurality of first end portions 22 arranged at intervals in the intersecting direction and a plurality of second end portions 23 arranged between the first end portions 22. The second end portions 23 are arranged in the second longitudinal direction X2 from the first end portions 22.

[0069] The dummy end portion 70D of the fourth embodiment includes a first dummy end portion 71D, a second dummy end portion 72D, and a third dummy end portion 73D. The first dummy end portion 71D is disposed between the second end portions 23. Therefore, the first dummy end portion 71D is disposed in the second longitudinal direction X2 relative to the first end portion 22. Therefore, the first dummy end portion 71D suppresses the movement of the anisotropic conductive resin layer 5 between the second end portions 23, and further suppresses the movement of the anisotropic conductive resin layer 5 from the first end portion 22 in the second longitudinal direction X2.

[0070] The second dummy end portion 72D is disposed in the second longitudinal direction X2 with respect to the second end portion 23. Therefore, the second dummy end portion 72D suppresses the anisotropic conductive resin layer 5 from moving from the second end portion 23 in the second longitudinal direction X2.

[0071] Two third dummy end portions 73D are provided. The first third dummy end portion 73D is arranged in the first intersecting direction Y1 of the second end portion 23A that is arranged furthest in the first intersecting direction Y1 among the multiple second end portions 23. The second third dummy end portion 73D is arranged in the second intersecting direction Y2 of the end portion 20B that is arranged furthest in the second intersecting direction Y2. This prevents the anisotropic conductive resin layer 5 from moving from the second end portion 23A in the first intersecting direction Y1. In addition, it prevents the anisotropic conductive resin layer 5 from moving from the second end portion 23B in the second intersecting direction Y2.

[0072] Although the embodiment and the modified examples have been described above, in which the dummy end portion is divided into multiple parts, the present disclosure may also integrate the multiple dummy end portions described in each embodiment and modified example. Also, in the embodiment, the electric circuit included in the array layer 30 is a load detection circuit that measures the load in the longitudinal direction and the transverse direction of the stretchable substrate 101, but the present disclosure may be a circuit other than this. [Explanation of symbols]

[0073] 5, 5A, 5B Anisotropic conductive resin layer 6. Conductive particles 7 Divided anisotropic conductive resin layer 8 Extension 10 Resin substrate 11 Body 12 Hinge part 13 Bend 19 Cutout section 20 End 21 Connection hinge part 22 First end 23 Second end 30 Array Layer 31 Load detection circuit 32 Strain gauge 40 Connection Wiring 41 First connection terminal 42 Wiring 50 1st resin layer 51 Page 1 60 2nd resin layer 70, 70D Dummy end 71, 71D First dummy end 72, 72D Second dummy end 73, 73D 3rd dummy end 100, 100A, 100C, 100D Stretchable Devices 101, 101A, 101C, 101D Stretchable Board 102 Flexible printed circuit board 104 Second connection terminal

Claims

1. a stretchable substrate having a first resin layer, a resin base material, an array layer, and a second resin layer stacked in that order; a flexible printed circuit board electrically connected to the electric circuit included in the array layer; Equipped with The resin substrate has a plurality of end portions spaced apart from one another, the electrical circuit having a plurality of first connection terminals disposed at the end portion; the flexible printed circuit board has a plurality of second connection terminals facing the first connection terminals, an anisotropic conductive resin layer is provided between the first connection terminal and the second connection terminal, the anisotropic conductive resin layer electrically connecting the first connection terminal and the second connection terminal; The first resin layer is A first surface on which the resin base material is provided; a dummy terminal portion provided on the first surface and disposed around the terminal portion; Equipped with Stretchable device.

2. the resin base material has a connection hinge portion extending along the first surface, The connecting hinge portion has an end portion in a longitudinal direction in which the connecting hinge portion extends, the end portion being connected to the terminal portion, The plurality of end portions are parallel to the first surface and are spaced apart in a transverse direction intersecting the longitudinal direction, The dummy end portion is disposed between the end portions adjacent to each other in the cross direction. The stretchable device of claim 1.

3. The connecting hinge portion is disposed on one side of the longitudinal direction relative to the end portion, The dummy end portion is disposed on the other side of the end portion in the longitudinal direction.

3. The stretchable device of claim 2.

4. the resin base material has a connecting hinge portion extending along the first surface, The connecting hinge portion is disposed on one side of the end portion in a longitudinal direction in which the connecting hinge portion extends, The other end of the connecting hinge portion in the longitudinal direction is connected to the end portion, The plurality of terminal portions include a plurality of first end portions that are parallel to the first surface and spaced apart in a transverse direction that intersects the longitudinal direction; A plurality of second ends disposed between the plurality of first ends; having the second end portion is disposed on the other side of the first end portion in the longitudinal direction, The dummy end portion is disposed between the second end portions and on the other side of the first end portions in the longitudinal direction. The stretchable device of claim 1.

5. The anisotropic conductive resin layer is disposed across the first surface, the plurality of end portions, and the first connection terminal. The stretchable device of claim 1.

6. The anisotropic conductive resin layer is disposed only on the plurality of end portions and the first connection terminal. The stretchable device of claim 1.

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