Stretchable device

Abstract

To provide a stretchable device high in sensitivity for detecting pressure.SOLUTION: A stretchable device includes a stretchable substrate, a sensor layer and a counter electrode laminated in this order. When viewed from the stretchable substrate, a direction of arranging the sensor layer is a first lamination direction, and a direction opposite to the first lamination direction is a second lamination direction; the stretchable substrate includes a resin base material and an array layer laminated in order in the first lamination direction; and the array layer includes a first surface facing the first lamination direction and contacting the sensor layer, a depression part depressed in the second lamination direction from the first surface, and a detection electrode arranged in the depression part and contacting the sensor layer only when the sensor layer moves in the second lamination direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] A stretchable device has a stretchable substrate that is excellent in elasticity and flexibility. As shown in Patent Document 1, the stretchable substrate has an array layer including an electric circuit and a resin substrate that serves as the base material for the array layer. When viewed from above, the stretchable substrate has body portions arranged in a matrix and hinge portions that connect the body portions together. The hinge portions have bending portions, such as arc-shaped portions, that extend between the body portions in a serpentine manner.

[0003] An example of an electric circuit included in the array layer is the pressure detection circuit shown in Patent Document 2. The pressure detection circuit has a detection electrode arranged on the surface of the stretchable substrate (surface of the array layer). In addition to the pressure detection circuit, the pressure detection device of Patent Document 2 also has a counter electrode facing the detection electrode, and a sensor layer arranged between the detection electrode and the counter electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-158622 [Patent Document 2] Japanese Patent Publication No. 2022-049511 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-described pressure detection device, the sensor layer and the detection electrode are in contact in the initial state (when no pressure is input). In other words, a small amount of current flows from the counter electrode to the detection electrode. Therefore, when determining whether pressure is present, the magnitude of the current flowing through the detection electrode is used as the criterion. On the other hand, if the increase in the current flowing through the detection electrode is small, it is difficult to determine whether pressure is being input, and the sensitivity for detecting the presence or absence of pressure is low.

[0006] The present invention aims to provide a stretchable device that has high sensitivity for detecting pressure. [Means for solving the problem]

[0007] A stretchable device according to one aspect of the present disclosure includes a stretchable substrate, a sensor layer, and a counter electrode, which are stacked in this order. A first stacking direction is a direction in which the sensor layer is arranged as viewed from the stretchable substrate, and a second stacking direction is a direction opposite to the first stacking direction. The stretchable substrate includes a resin base material and an array layer, which are stacked in this order in the first stacking direction. The array layer has a first surface facing the first stacking direction and in contact with the sensor layer, a recess recessed from the first surface in the second stacking direction, and a detection electrode disposed in the recess and coming into contact with the sensor layer only when the sensor layer moves in the second stacking direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a stretchable device according to a first embodiment, viewed from the side facing the front surface. [Figure 2] FIG. 2 is a diagram schematically illustrating a cross section of the stretchable device according to the first embodiment taken along a gate line. [Figure 3] FIG. 3 is a cross-sectional view taken along line VI-VI in FIG. [Figure 4] FIG. 4 is a plan view of the first surface of the stretchable substrate of the first embodiment, viewed from the sensor layer side. [Figure 5]FIG. 5 is a cross-sectional view of the stretchable device of the first embodiment taken along line VV in FIG. [Figure 6] FIG. 6 is a diagram showing an electric circuit of a pressure detection circuit of the stretchable device of the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view of the stretchable device of the first embodiment when pressure is applied to the surface thereof. [Figure 8] FIG. 8 is an enlarged view of the body portion of the stretchable substrate of the first modification, viewed from the first stacking direction. [Figure 9] FIG. 9 is an enlarged view of the body portion of the stretchable substrate of the second modification, viewed from the first stacking direction. DETAILED DESCRIPTION OF THE INVENTION

[0009] Modes (embodiments) for carrying out 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. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. Note that the disclosure is merely an example, and any appropriate modifications that a person skilled in the art can easily make while maintaining the gist of the invention are naturally included within the scope of the present invention. For clarity of explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual embodiment. However, these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each figure, components similar to those described above with reference to the previous figures are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] Furthermore, in this specification and claims, when expressing an aspect of placing another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is placed directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is placed above a certain structure via yet another structure.

[0011] (Embodiment 1) FIG. 1 is a perspective view of a stretchable device according to embodiment 1, viewed from the side opposite the front surface. As shown in FIG. 1, the stretchable device 100 is formed in a flat plate shape. The stretchable device 100 has a front surface 1 and a back surface 2 facing in opposite directions (the back surface 2 is not shown in FIG. 1; see FIGS. 2 and 3). The front surface 1 is a surface on which pressure can be detected. Hereinafter, the directions parallel to the front surface 1 and the back surface 2 will be referred to as the planar direction. Furthermore, the direction intersecting the planar direction will be referred to as the stacking direction.

[0012] When viewed from the direction opposite to the surface 1, the stretchable device 100 is divided into a detection region 5 and a frame region 6. Note that the imaginary line M shown in FIG. 1 indicates the boundary between the detection region 5 and the frame region 6. The detection region 5 is the range in which pressure can be detected. The detection region 5 is located in the center of the stretchable device 100, and is rectangular (quadrilateral) when viewed from the direction opposite to the surface 1. The frame region 6 is the range in which pressure cannot be detected. The frame region 6 is located on the edge of the stretchable device 100, and is frame-shaped (quadrilateral frame-shaped).

[0013] The detection area 5 is divided into a plurality of individual detection areas 7. That is, pressure can be detected for each individual detection area 7. The plurality of individual detection areas 7 are arranged in a first direction X that is parallel to the planar direction and a second direction Y that is parallel to the planar direction and intersects with the first direction X. In this embodiment, the first direction X is parallel to the short side 3, and the second direction Y is parallel to the long side 4.

[0014] Fig. 2 is a diagram schematically showing a cross section of the stretchable device according to embodiment 1 taken along a gate line. Fig. 3 is a cross section taken along line VI-VI in Fig. 4. As shown in Figs. 2 and 3, the stretchable device 100 has a first stretchable resin layer 60, a stretchable substrate 10, a sensor layer 40, a counter electrode 50, and a second stretchable resin layer 70, which are stacked in this order in the stacking direction. In other words, the stretchable substrate 10, the sensor layer 40, and the counter electrode 50 are sandwiched between a pair of stretchable resin layers (the first stretchable resin layer 60 and the second stretchable resin layer 70).

[0015] Hereinafter, with regard to the stacking direction, the direction in which the second stretchable resin layer 70 is arranged as viewed from the first stretchable resin layer 60 will be referred to as the first stacking direction Z1, and the direction opposite to the first stacking direction Z1 will be referred to as the second stacking direction Z2.

[0016] The first stretchable resin layer 60 and the second stretchable resin layer 70 have insulating properties, stretchability, and flexibility. Examples of resins used for the first stretchable resin layer 60 and the second stretchable resin layer 70 include acrylic elastomers. Note that the first stretchable resin layer 60 and the second stretchable resin layer 70 of the present disclosure are not limited to acrylic elastomers, and may be acrylic resin, epoxy resin, urethane resin, or the like, without any particular limitation.

[0017] The first stretchable resin layer 60 and the second stretchable resin layer 70 are each formed in a plate shape and extend in a planar direction. The surface of the first stretchable resin layer 60 in the second stacking direction Z2 constitutes the back surface 2 of the stretchable device 100. The first stretchable resin layer 60 has a stacking surface 61 facing the first stacking direction Z1 and facing the stretchable substrate 10.

[0018] The stretchable substrate 10 extends in a planar direction along the lamination surface 61. The stretchable substrate 10 has a first surface 11 facing a first lamination direction. The shape of the stretchable substrate 10 when viewed in plan will be described later. The stretchable substrate 10 has a resin base material 12 overlaid on the lamination surface 61 of the first elastic resin layer 60, and an array layer 13 overlaid on the resin base material 12 in a first lamination direction Z1.

[0019] The resin base material 12 is adhered to the lamination surface 61 of the first elastic resin layer 60. The resin base material 12 has elasticity, flexibility, and insulating properties. The resin base material 12 is made of a resin material such as polyimide.

[0020] Although not shown, the array layer 13 includes a plurality of insulating layers stacked in the stacking direction and a pressure detection circuit. The pressure detection circuit will be described in detail later. Of the plurality of insulating layers in the array layer 13, the insulating layer arranged furthest in the first stacking direction Z1 constitutes the first surface 11. In other words, the array layer 13 has the first surface 11 that faces the first stacking direction Z1 and abuts against the sensor layer 40.

[0021] The surface of the second stretchable resin layer 70 in the first stacking direction Z1 constitutes the surface 1 of the stretchable device 100. The second stretchable resin layer 70 faces the second stacking direction Z2 and has an opposing surface 71 facing the stretchable substrate 10.

[0022] A counter electrode 50 is bonded to the opposing surface 71 of the second elastic resin layer 70. The counter electrode 50 extends in the planar direction, is made of a metal material, and is formed across the multiple individual detection regions 7. When viewed from above, the counter electrode 50 is a so-called solid film that is provided across the entire detection region 5. The counter electrode 50 is connected to the common wiring 38 (see FIG. 1) via wiring (not shown). This allows a constant amount of current to be supplied to the counter electrode 50 from the driving IC. The sensor layer 40 is bonded to the surface 51 of the counter electrode 50 that faces the second stacking direction Z2.

[0023] The sensor layer 40 is made of a material containing conductive particles inside a highly insulating resin layer. The particles are dispersed inside the resin layer and spaced apart from one another. Therefore, the resistance of the sensor layer 40 is high when the resin layer is not deformed. On the other hand, when the resin layer is compressed, the particles come into contact or close to each other, reducing the resistance of the sensor layer 40. Furthermore, as the amount of compression of the resin layer increases, the amount of contact between the particles increases, significantly reducing the resistance of the sensor layer 40. Furthermore, when viewed in a plan view, the sensor layer 40 is provided over the entire detection area 5. A surface 41 of the sensor layer 40 facing the second stacking direction Z2 abuts against the first surface 11 of the stretchable substrate 10.

[0024] A frame portion 62 is provided on the edge of the first stretchable resin layer 60, protruding in the first stacking direction Z1 beyond the stacking surface 61. The frame portion 62 is formed in a ring shape in a plan view. The stretchable substrate 10, the sensor layer 40, and the counter electrode 50 are arranged inside the frame portion 62. A surface 63 of the frame portion 62 in the first stacking direction Z1 is bonded to an opposing surface 71 of the second stretchable resin layer 70. As a result, the first stretchable resin layer 60 and the second stretchable resin layer 70 cooperate with each other to form a housing that houses the stretchable substrate 10.

[0025] 3, a plurality of lightening holes 19 penetrating in the stacking direction are formed in the stretchable substrate 10. The first stretchable resin layer 60 has a plurality of protrusions 64 that protrude from the stacking surface 61 in the first stacking direction Z1 and fill the lightening holes 19.

[0026] Although the lightening holes 19 in this embodiment are filled with the first stretchable resin layer 60, in the present disclosure they may be filled with the second stretchable resin layer 70. Alternatively, the lightening holes 19 may be filled with both the first stretchable resin layer 60 and the second stretchable resin layer 70. Alternatively, the lightening holes 19 may be filled with a resin other than the first stretchable resin layer 60 and the second stretchable resin layer 70. Alternatively, the lightening holes 19 may be empty, leaving them as empty spaces.

[0027] Fig. 4 is a plan view of the first surface of the stretchable substrate of Embodiment 1, viewed from the sensor layer side. As shown in Fig. 4, the stretchable substrate 10 includes a plurality of body portions 20 and a plurality of hinge portions 21 that extend in a planar direction while meandering.

[0028] The body portions 20 are arranged so that one body portion 20 overlaps the other in the stacking direction in each individual detection area 7 (see FIG. 1). Therefore, the body portions 20 are arranged with intervals in the first direction X and the second direction Y. The body portions 20 have an octagonal shape in plan view. Note that the shape of the body portions 20 in plan view in the present disclosure is not limited to an octagonal shape, and may be a circle or another polygonal shape.

[0029] The hinge portions 21 connect adjacent body portions 20 to each other. There are two types of hinge portions 21: a first hinge portion 21A extending in a first direction X, and a second hinge portion 21B extending in a second direction Y. When the first hinge portion 21A is rotated 90 degrees, it takes on the same shape as the second hinge portion 21B. In addition, in the stretchable substrate 10, portions where the body portions 20 and hinge portions 21 are not provided are formed as lightening holes 19 that penetrate in the stacking direction.

[0030] 3, the lightening holes 19 are filled with the first elastic resin layer 60. Therefore, the rigidity of the hinge portion 21 adjacent to the first elastic resin layer 60 in the first direction X or the second direction Y is low. In other words, when an expansion / contraction load acts in the first direction X or the second direction Y, the hinge portion 21 of the stretchable substrate 10 deforms. On the other hand, the body portion 20 has a higher rigidity than the hinge portion 21, and therefore the amount of deformation is kept small.

[0031] The hinge portion 21 has two arc-shaped arc portions 22, 23, which cause it to meander. One of the arc portions 22, 23 in the first hinge portion 21A is a first arc portion 22A that protrudes in one direction in the second direction Y, and the other is a second arc portion 23A that protrudes in the other direction in the second direction Y. One of the arc portions 22, 23 in the second hinge portion 21B is a first arc portion 22B that protrudes in one direction in the first direction X, and the other is a second arc portion 23B that protrudes in the other direction in the first direction X.

[0032] For example, when a tensile load acts on both ends of hinge portion 21, arc portions 22 and 23 are deformed so that the radius of curvature increases, which increases the distance between two body portions 20 connected to both ends of hinge portion 21, and stretchable substrate 10 elongates.

[0033] On the other hand, when a compressive load is applied to both ends of hinge portion 21, arc portions 22 and 23 are deformed so that the radius of curvature decreases, thereby reducing the distance between two body portions 20 connected to both ends of hinge portion 21, and stretchable substrate 10 contracts.

[0034] Furthermore, linear base portions 24 are provided at both ends of hinge portion 21 to connect to body portion 20. Note that, although hinge portion 21 in this embodiment has arc-shaped arc portions 22, 23, the present disclosure is not limited to the hinge portion shown in the embodiment, and may have an L-shaped bent portion instead of arc portions 22, 23.

[0035] 5 is a cross-sectional view of the stretchable device of embodiment 1 cut along the line VV in FIG. 4. As shown in FIG. 5, a recess 15 recessed in the second stacking direction is provided on the first surface 11 of the stretchable substrate 10. The recess 15 is provided in the body portion 20. That is, the recess 15 is provided in an area that overlaps the entire body portion 20 when viewed in a plan view. Therefore, the first surface 11 is composed only of the surfaces of the multiple hinge portions 21 in the first stacking direction. Note that the recess 15 is omitted from FIG. 4.

[0036] 4, the stretchable substrate 10 (array layer 13) has a plurality of detection electrodes 30 as a component of the pressure detection circuit. One detection electrode 30 is provided for each body portion 20. In other words, one detection electrode 30 is provided for each individual detection area 7.

[0037] 5, the detection electrode 30 is disposed on the bottom surface 16 of the recess 15 of the stretchable substrate 10. The depth H of the recess 15 in the stacking direction is 3 μm or more and 10 μm or less, which is smaller than the thickness of the detection electrode 30. Therefore, the detection electrode 30 is separated from the sensor layer 40.

[0038] As shown in FIG. 5, the stretchable substrate 10 (array layer 13) has a plurality of driving transistors 31 as a component of the pressure detection circuit. One driving transistor 31 is provided for each body portion 20. Therefore, one detection electrode 30 is provided for each individual detection region 7. The driving transistor 31 includes a semiconductor layer 31a, a gate insulating film 31b, a gate electrode 31c, a drain electrode 31d, and a source electrode 31e. The source electrode 31e is electrically connected to the detection electrode 30.

[0039] In addition, the stretchable substrate 10 (array layer 13) has gate lines 32 (see Figure 4), signal lines 33 (see Figure 4), connection parts 35 (see Figure 1), gate line driving circuits 36 (see Figure 1), and signal line selection circuits 37 (see Figure 1) as components of the pressure detection circuit.

[0040] 6 is a diagram showing an electrical circuit of the pressure detection circuit of the stretchable device of Embodiment 1. As shown in Fig. 6, the gate lines 32 extend in a first direction X. The signal lines 33 extend in a second direction Y.

[0041] 4, the gate line 32 is disposed across a plurality of first hinge portions 21A and a plurality of body portions 20, and thus extends in the first direction X. A plurality of gate lines 32 are also provided in the second direction Y. The gate line 32 is connected to the gate electrode 31c of the driving transistor 31 in each body portion 20. Furthermore, as shown in FIG. 6, a plurality of driving transistors 31 arranged in the first direction X are connected to one gate line 32.

[0042] The signal line 33 is disposed across the second hinge portions 21B and the body portions 20, and thus extends in the second direction Y. A plurality of signal lines 33 are provided in the first direction X. The signal line 33 is connected to the drain electrode 31d of the driving transistor 31. As shown in FIG. 6, a plurality of driving transistors 31 arranged in the second direction Y are connected to one signal line 33.

[0043] The connection section 35, the gate line driving circuit 36, and the signal line selection circuit 37 are arranged in the frame region 6 of the array layer 13. The connection section 35 is for connection to a driving IC (Integrated Circuit) arranged outside the stretchable device 100. In the present disclosure, the driving IC may be mounted as a COF (Chip On Film) on a flexible printed circuit board or a rigid board connected to the connection section 35. Alternatively, the driving IC may be mounted as a COG (Chip On Glass) in the frame region 6.

[0044] The gate line driving circuit 36 is a circuit that drives the multiple gate lines 32 (see FIG. 4) based on various control signals from the driving IC. The gate line driving circuit 36 selects the multiple gate lines 32 sequentially or simultaneously, and supplies gate driving signals to the selected gate lines 32.

[0045] The signal line selection circuit 37 is a switch circuit that sequentially or simultaneously selects multiple signal lines 33 (see FIG. 4). The signal line selection circuit 37 is, for example, a multiplexer. The signal line selection circuit 37 connects the selected signal line 34 to the driving IC based on a selection signal supplied from the driving IC. As described above, when the gate line 32 is scanned, the detection electrode 30 and the signal line 33 are electrically connected. Therefore, the electrical signal (current value) input to the detection electrode 30 is transmitted to the driving IC via the signal line 33.

[0046] 1, a common wiring 38 and a common electrode wiring (not shown) are provided in the frame region 6 of the array layer 13. The common wiring 38 is a wiring for supplying a predetermined voltage to the counter electrode 50, and extends along the frame region 6. The common wiring 38 is connected to a driving IC via a connection portion 35, and a constant voltage is supplied from the driving IC to the common wiring 38.

[0047] Next, the effects of the stretchable device 100 of embodiment 1 will be described. As shown in Fig. 5, when no pressure is applied to the surface 1, a gap is provided between the sensor layer 40 and the detection electrode 30, and the sensor layer 40 and the detection electrode 30 are not in contact with each other. Therefore, no electrical signal is output from the detection electrode 30 via the signal line 33 (the amount of current is zero).

[0048] 7 is a cross-sectional view of the stretchable device of embodiment 1 when pressure is applied to the surface. As shown in FIG. 7, when pressure F is applied to surface 1, the second stretchable resin layer, the counter electrode, and the sensor layer are pressed in the second stacking direction. This causes the sensor layer to contact the detection electrode 30. This establishes electrical continuity between the counter electrode and the detection electrode via the sensor layer 40, and an electrical signal flows to the detection electrode.

[0049] Furthermore, when the pressure increases, the sensor layer 40 is compressed in the stacking direction between the detection electrode 30 and the counter electrode 50. This reduces the resistance value of the sensor layer, and increases the electrical signal (current value) flowing through the detection electrode.

[0050] As described above, according to the stretchable device 100 of embodiment 1, the sensor layer 40 and the detection electrode 30 come into contact with each other and an electrical signal is detected only when the sensor layer 40 moves in the second stacking direction Z2 (when pressure is input). In other words, it is easy to determine whether pressure is being input, and pressure detection sensitivity is high.

[0051] The above has described the first embodiment. Next, a modified example in which the recess 15 is modified will be described.

[0052] FIG. 8 is an enlarged view of the body portion of the stretchable substrate of Modification 1 as viewed from the first stacking direction. As shown in FIG. 8, recess 15A of stretchable device 100A of Modification 1 is rectangular and similar in shape to detection electrode 30. Recess 15A is also smaller than the body portion. Therefore, not only the surface of hinge portion 21 in the first stacking direction but also the surface of body portion 20 in the first stacking direction constitutes first surface 11. The present disclosure may be modified as described above as Modification 1, and the same effects as those of Embodiment 1 can be obtained.

[0053] 9 is an enlarged view of the body portion of the stretchable substrate of Modification 2 as viewed from the first stacking direction. As shown in Fig. 9, the recess 15B of the stretchable device 100B of Modification 2 extends not only to the body portion 20 but also to the base portion 24 of the hinge portion 21. Note that the detection electrode 30 in the embodiment and modifications is arranged so as to overlap only the body portion 20, but as shown in Modification 2, if the recess 15B extends to the base portion 24, a portion of the detection electrode 30 may be arranged on the base portion 24.

[0054] Although the embodiments and modifications have been described above, the present disclosure is not limited to the examples shown in the embodiments and modifications. For example, in the first embodiment, the entire surface of the hinge portion 21 in the first stacking direction constitutes the first surface 11, but a portion of the surface of the hinge portion 21 in the first stacking direction may be cut out. Furthermore, as shown in the first modification, when a portion of the surface of the body portion 20 in the first stacking direction constitutes the first surface 11, the surface of the hinge portion 21 in the first stacking direction may be recessed from the first surface 11. [Explanation of symbols]

[0055] 1 surface 2 Back side 5 Detection Area 6 Frame Area 7 Individual detection areas 10 Stretchable PCB 11 Page 1 12 Resin substrate 13 Array Layer 15 recess 16 Bottom 19 Hole 20 Body 21 Hinge part 21A First hinge part 21B Second hinge part 22, 23 Arc section 24 base 30 detection electrode 31 Drive transistor 32 gate lines 33 Signal line 40 Sensor Layer 50 Counter electrode 60 1st stretchable resin layer 70 Second elastic resin layer 100 Stretchable Device

Claims

1. a stretchable substrate, a sensor layer, and a counter electrode, which are stacked in order; A direction in which the sensor layer is arranged as viewed from the stretchable substrate is a first stacking direction, and a direction opposite to the first stacking direction is a second stacking direction; the stretchable substrate has a resin base material and an array layer stacked in order in the first stacking direction, The array layer comprises: a first surface facing the first stacking direction and in contact with the sensor layer; a recess recessed from the first surface in the second stacking direction; a detection electrode disposed in the recess and coming into contact with the sensor layer only when the sensor layer moves in the second stacking direction; A stretchable device having:

2. The stretchable substrate is Body portions spaced apart from each other; a plurality of hinge portions connecting the body portions to each other; and The recess is provided on the first surface of the body portion. The stretchable device of claim 1 .

3. a first elastic resin layer disposed in the second stacking direction relative to the stretchable substrate; a second elastic resin layer disposed in the first stacking direction relative to the counter electrode; The stretchable device according to claim 1 or 2, comprising:

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