Telescopic device

Abstract

A stretchable device (1) is provided with: a stretchable base material (11) having a main surface (111); an electronic component (30) provided on the main surface (111) of the stretchable base material (11); a first stretchable wiring (21) connected to the electronic component (30); and a second stretchable wiring (22) connected to the first stretchable wiring (21), a first end portion (211) of the first stretchable wiring (21) in the direction of extension being connected to the electronic component (30), and a second end portion (212) of the first stretchable wiring (21) in the direction of extension being connected to a first end portion (221) of the second stretchable wiring (22) in the direction of extension.

Description

Technical Field

[0001] The present disclosure relates to a telescopic device. Background Art

[0002] Conventionally, there is a device described in International Publication No. 2009 / 081929 (Patent Document 1) as a telescopic device. The telescopic device includes an insulating substrate, a first conductor having a pad provided on the insulating substrate, a second conductor provided on the pad, solder provided separately on the second conductor, and an electronic component having an electrode portion that is in independent contact with the solder.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2009 / 081929 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the conventional device, the end of the electronic component is arranged to overlap with the overlapping region between the first conductor and the second conductor, and the solder provided on the second conductor is also arranged to overlap with the overlapping region.

[0008] In addition, the conventional device of the above structure was evaluated, and it was found that the mechanical strength of the conventional device was low. A detailed study showed that when a stretchable substrate with stretchability is used as the substrate, the stress during elongation is concentrated to the greatest extent near the interface between the connecting member such as solder and the wiring. Therefore, it was found that the conventional device may cause disconnection of the wiring, peeling of the interface between the substrate and the wiring, etc.

[0009] Therefore, an object of the present disclosure is to provide a telescopic device capable of improving mechanical strength.

[0010] Solutions for solving problems

[0011] In order to achieve the above object, a telescopic device according to one embodiment of the present invention includes:

[0012] a telescopic substrate having a major surface;

[0013] an electronic component disposed on the main surface of the telescopic substrate;

[0014] a first retractable wiring connected to the electronic component; and

[0015] a second telescopic wiring connected to the first telescopic wiring,

[0016] A first end portion of the first telescopic wiring in an extending direction is connected to the electronic component.

[0017] The second end portion of the first telescopic wiring in the extending direction is connected to the first end portion of the second telescopic wiring in the extending direction.

[0018] Effects of the Invention

[0019] According to the telescopic device of one aspect of the present disclosure, the mechanical strength can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic perspective view partially showing the telescopic device according to the first embodiment of the present disclosure.

[0021] Figure 2 yes Figure 1 II-II sectional view.

[0022] Figure 3 It is a schematic perspective view showing a telescopic device according to a second embodiment of the present disclosure.

[0023] Figure 4 It is a schematic plan view partially showing a telescopic device according to a second embodiment of the present disclosure.

[0024] Figure 5 This is a graph showing the relationship between stress and elongation of the telescopic wiring in the example.

[0025] Figure 6 This is a graph showing the thickness dependency of the relationship between the expansion / contraction ratio and the resistance value of the expandable / contractable wiring according to the example.

[0026] Figure 7 It is a schematic perspective view partially showing the expansion and contraction device according to the embodiment.

[0027] Fig. 8A It is a figure which shows the coating shape of a slurry.

[0028] Figure 8B It is a figure which shows the coating shape of a slurry. DETAILED DESCRIPTION

[0029] The following detailed description of the embodiments of the present disclosure is provided using the accompanying drawings. In each embodiment, the aspects that are different from the embodiments described before the embodiment are mainly described. In particular, the same effects achieved by the same structure are not mentioned one by one for each embodiment. Among the constituent elements of the following embodiments, the constituent elements that are not described in the independent claims are described as arbitrary constituent elements. In addition, the sizes and size ratios of the constituent elements shown in the drawings are not necessarily strict. In addition, in each figure, there is a case where the same figure mark is marked on substantially the same structure and repeated descriptions are omitted or simplified.

[0030] [First embodiment]

[0031] (Overall structure)

[0032] Reference Figure 1 and Figure 2 The overall structure of the expansion and contraction device 1 according to the first embodiment will be described. Figure 1 It is a schematic perspective view partially showing the expansion and contraction device 1 . Figure 2 yes Figure 1 II-II sectional view. In addition, Figure 1 The description of the coating layer is omitted.

[0033] In the drawings of this specification, the thickness direction of the telescopic base is indicated by an arrow T. The "direction perpendicular to the main surface of the telescopic base" described in the claims corresponds to the T direction. In addition, in this specification, the direction from the main surface of the telescopic base where the telescopic wiring is not provided toward the main surface of the telescopic base where the telescopic wiring is provided in the T direction is referred to as the upper side.

[0034] The stretchable device 1 includes a stretchable base material 11 having a main surface 111, an electronic component 30 provided on the main surface 111 of the stretchable base material 11, a first stretchable wiring 21 connected to the electronic component 30, a second stretchable wiring 22 connected to the first stretchable wiring 21, and a covering layer 50 provided so as to cover the first stretchable wiring 21 and the second stretchable wiring 22. The stretchable device 1 is used, for example, to be attached to a living body to measure a biological signal.

[0035] Here, "on the main surface of the telescopic substrate" does not refer to an absolute direction such as the vertically upward direction defined in the direction of gravity, but refers to the direction toward the outer side of the outer side and the inner side of the telescopic substrate separated by the main surface of the telescopic substrate. Therefore, "on the main surface of the telescopic substrate" is a relative direction determined by the direction of the main surface of the telescopic substrate. In addition, "on" relative to a certain element includes not only the position directly above the element in contact with the element (on), but also the position above the element separated from the element, that is, the position above other objects on the element, and the position above the spaced-apart element (above).

[0036] The stretchable substrate 11 is a sheet-like or film-like substrate made of a stretchable resin material. Examples of the resin material include thermoplastic polyurethane (TPU). The thickness of the stretchable substrate 11 is not particularly limited, but from the perspective of not hindering the expansion and contraction of the biological surface when attached to the biological body, it is preferably less than 1 mm, more preferably less than 100 μm, and further preferably less than 50 μm. In addition, the thickness of the stretchable substrate 11 is preferably greater than 1 μm. The shape of the stretchable substrate 11 is not particularly limited. In this embodiment, the stretchable substrate 10 is a shape extending in one direction A when viewed from the thickness direction T.

[0037] The electronic component 30 is, for example, a capacitor component, an inductor component, an IC (semiconductor integrated circuit), etc. The type of the electronic component 30 is not particularly limited. The shape of the electronic component 30 is not particularly limited, but in this embodiment, it is a rectangular parallelepiped. The electronic component 30 is arranged in a manner that the length direction is parallel to the extension direction of the telescopic substrate 11 (hereinafter referred to as "A direction"). External electrodes 31 are respectively provided at both ends of the electronic component 30 in the A direction.

[0038] The first telescopic wiring 21 is a component having functions such as alleviating stress applied to the telescopic device 1. The first telescopic wiring 21 is formed of a conductive material having elasticity. The conductive material may be, for example, a metal foil of silver, copper, nickel, etc., or a mixture of metal powder of silver, copper, nickel, etc. and an elastomeric resin such as an epoxy resin, a polyurethane resin, an acrylic resin, and a silicone resin. Preferably, the Young's modulus of the first telescopic wiring 21 is greater than the Young's modulus of the second telescopic wiring 22. The shape of the first telescopic wiring 21 is not particularly limited, but in this embodiment, it is a shape extending in one direction. Specifically, the extension direction of the first telescopic wiring 21 is parallel to the A direction.

[0039] The first end portion 211 of the first telescopic wiring 21 in the extending direction is connected to the electronic component 30. Specifically, the first end portion 211 of the first telescopic wiring 21 in the extending direction is connected to the external electrode 31 on one side of the electronic component 30 via the connecting member 40. The connecting member 40 is, for example, solder, a conductive adhesive, or the like.

[0040] The length L1 of the first telescopic wiring 21 in the extension direction is preferably, for example, 0.2 mm or more and 5 mm or less. In this specification, the length L1 does not include the overlapped portion with the second telescopic wiring 22. The width W1 of the first telescopic wiring 21 in the direction perpendicular to the extension direction is preferably, for example, 0.2 mm or more and 3.2 mm or less. The thickness t1 of the first telescopic wiring 21 in the T direction is preferably, for example, 10 μm or more and 30 μm or less.

[0041] The second telescopic wiring 22 is a wiring that is mainly responsible for the transmission and reception of biological signals, etc. The second telescopic wiring 22 is formed of a conductive material with elasticity. The conductive material can be, for example, a metal foil of silver, copper, nickel, etc., or a mixture composed of metal powder of silver, copper, nickel, etc. and an elastomeric resin such as epoxy resin, polyurethane resin, acrylic resin and silicone resin. The shape of the second telescopic wiring 22 is not particularly limited, but in this embodiment, it is a shape extending in one direction. Specifically, the extension direction of the second telescopic wiring 22 is parallel to the A direction. That is, the extension direction of the second telescopic wiring 22 is parallel to the extension direction of the first telescopic wiring 21. The "parallel" in this application is not limited to a strict parallel relationship, and takes into account the range of actual deviations, and also includes a substantial parallel relationship.

[0042] The first end 221 of the second telescopic wire 22 in the extending direction is connected to the second end 212 of the first telescopic wire 21 in the extending direction. Specifically, the first end 221 of the second telescopic wire 22 in the extending direction is stacked on the second end 212 of the first telescopic wire 21 in the extending direction and connected to the second end 212 of the first telescopic wire 21 in the extending direction. However, the present invention is not limited thereto, and the second end 212 of the first telescopic wire 21 in the extending direction may be stacked on the first end 221 of the second telescopic wire 22 in the extending direction and connected to the first end 221 of the second telescopic wire 22 in the extending direction. The length L3 in the A direction of the portion (overlapping portion) 22P of the second telescopic wire 22 that overlaps with the first telescopic wire 21 is preferably, for example, not less than 0.1 mm and not more than 1 mm.

[0043] The length L2 of the second telescopic wiring 22 in the extending direction is preferably three times or more of the length L1. In this specification, the length L2 does not include the overlapped portion with the first telescopic wiring 21. Figure 7 As shown in FIG. 1 , when there are a plurality of electronic components 30 and one second telescopic wiring 22 is connected to the plurality of electronic components 30, L2 is set to a length to a midpoint between the electronic components 30 adjacent in the extension direction of the second telescopic wiring 22. The width W2 of the second telescopic wiring 22 in a direction perpendicular to the extension direction is preferably, for example, 0.2 mm or more and 3.2 mm or less. The thickness t2 of the second telescopic wiring 22 in the T direction is preferably, for example, 10 μm or more and 30 μm or less.

[0044] In this embodiment, there are two groups of telescopic wiring groups consisting of the first telescopic wiring 21 connected to the external electrode 31 of the electronic component 30 and the second telescopic wiring 22 connected to the first telescopic wiring 21, corresponding to the two external electrodes 31 set at the two ends of the electronic component 30 in the A direction.

[0045] The covering layer 50 protects the first telescopic wiring 21 and the second telescopic wiring 22 from the external environment. The covering layer 50 is, for example, a potting resin. The covering layer 50 is preferably a resin material having elasticity, for example, preferably an ionomer resin, a polyester resin, a styrene resin, an olefin resin, an epoxy resin, a polyurethane resin, an acrylic resin or a silicone resin, more preferably a polyurethane resin. In addition, although the covering layer 50 may not be provided, it is preferred that the covering layer 50 at least covers the connection portion between the first telescopic wiring 21 and the electronic component 30.

[0046] According to the telescopic device 1, since the first end 211 of the first telescopic wire 21 in the extending direction is connected to the electronic component 30, and the second end 212 of the first telescopic wire 21 in the extending direction is connected to the first end 221 of the second telescopic wire 22 in the extending direction, the end of the electronic component 30 does not overlap with the connecting portion between the first telescopic wire 21 and the second telescopic wire 22 when viewed from the direction orthogonal to the main surface 111 of the telescopic base 11. Furthermore, the connecting member 40 connecting the electronic component 30 and the first telescopic wire 21 can also be arranged so as not to overlap with the connecting portion between the first telescopic wire 21 and the second telescopic wire 22. Thus, different members can be arranged stepwise from the end of the electronic component 30 toward the second telescopic wire 22. As a result, the stress that would otherwise concentrate on the connecting portion between the electronic component 30 and the first telescopic wire 21 can be dispersed from the end of the electronic component 30 toward the second telescopic wire 22, thereby alleviating the concentration of the stress. As a result, the mechanical strength of the telescopic device 1 can be improved.

[0047] (tensile load ratio)

[0048] In the stretchable device 1, it is preferable that the following formula (1) and formula (2) are satisfied. In the following description, the stretching direction is parallel to the A direction.

[0049] σ1≤ allowable stress σ1 of the first expansion wiring max ···(1)

[0050] σ2≤ allowable stress σ2 of the second expansion wiring max ···(2)

[0051] in,

[0052] σ1=(δ×E1×S2×E2) / (L1×S2×E2+L2×S1×E1)···(3)

[0053] σ2=(δ×E1×S1×E2) / (L1×S2×E2+L2×S1×E1)···(4)

[0054] δ: The total displacement of the first and second telescopic wirings 21 and 22

[0055] L1: Length of the first extendable wiring 21 in the extension direction (direction A)

[0056] L2: length of the second telescopic wiring 22 in the telescopic direction

[0057] S1: cross-sectional area of ​​the first stretchable wiring 21 in a cross section perpendicular to the stretching direction (width W1 of the first stretchable wiring 21×thickness t1)

[0058] S2: cross-sectional area of ​​the second stretchable wiring 22 in a cross section perpendicular to the stretching direction (width W2 of the second stretchable wiring 22×thickness t2)

[0059] E1: Elastic coefficient of the first telescopic wiring 21

[0060] E2: Elastic coefficient of the second telescopic wiring 22

[0061] The above σ1 represents the tensile load acting on the first telescopic wiring 21 when the displacement δ is given to the entirety of the first telescopic wiring 21 and the second telescopic wiring 22. The above σ2 represents the tensile load acting on the second telescopic wiring 22 when the displacement δ is given to the entirety of the first telescopic wiring 21 and the second telescopic wiring 22. That is, satisfying the above formula (1) and formula (2) means that the first tensile load ratio and the second tensile load ratio calculated by the following formula are respectively less than 1.

[0062] First tensile load ratio=(tensile load σ1 acting on the first stretchable wiring 21) / (allowable stress σ1 of the first stretchable wiring 21) max )

[0063] Second tensile load ratio=(tensile load σ2 acting on the second stretchable wiring 22) / (allowable stress σ2 of the second stretchable wiring 22) max )

[0064] Here, the derivation of the above-mentioned formula (3) and formula (4) as calculation formulas for the tensile load σ1 and the tensile load σ2 is described. When the displacement δ is given to the first and second telescopic wirings 21 and 22 as a whole, the load F applied to the first and second telescopic wirings 21 and 22 is expressed by the following formula.

[0065] F=δ / [{L1 / (E1×S1)}+{L2 / (E2×S2)}]

[0066] The tensile load σ1 and the tensile load σ2 are derived from the following equations using the load F.

[0067] σ1=F / S1=(δ / S1)×{(E1×S1×E2×S2) / (L1×S2×E2+L2×S1×E1)}=(δ×E1×S2×E2) / (L1×S2×E2+L2×S1×E1)

[0068] σ2=F / S2=(δ / S2)×{(E1×S1×E2×S2) / (L1×S2×E2+L2×S1×E1)}=(δ×E1×S1×E2) / (L1×S2×E2+L2×S1×E1)

[0069] According to the above formula (3) and formula (4), the tensile load σ1 and the tensile load σ2 can be adjusted by adjusting the elastic modulus E1 and E2, the length L1 and L2 in the expansion and contraction direction, the cross-sectional area S1 and S2, and the length L3 of the portion where the first expansion and contraction wire 21 and the second expansion and contraction wire 22 overlap each other. In addition, when the length of each member of the first expansion and contraction wire 21 and the second expansion and contraction wire 22 in the extension direction is a predetermined length, the length L1 and L2 of the first expansion and contraction wire 21 and the second expansion and contraction wire 22 in the expansion and contraction direction can be adjusted by adjusting the length of the portion where the first expansion and contraction wire 21 and the second expansion and contraction wire 22 overlap each other.

[0070] In addition, although the calculation of the tensile load σ1 and the calculation of the tensile load σ2 are shown for one of the two telescopic wiring groups, the calculation is the same for the other group. That is, δ, L1, L2, S1, S2, E1 and E2 can be defined for each of the two telescopic wiring groups.

[0071] The allowable stress σ1 of the first expansion / contraction wiring 21 in the above equation (1) is max It is the stress at the maximum elongation of the first stretchable wiring 21. The allowable stress σ1 of the first stretchable wiring 21 max For example, the following setting may be performed: the first stretchable wiring 21 is cut into a predetermined length in the extension direction, and then the relationship between the elongation and stress of the first stretchable wiring 21 is measured (stress-strain diagram), and the allowable stress σ1 max The allowable stress σ2 of the second stretchable wiring 22 in the above formula (2) is defined as the stress when the first stretchable wiring 21 is broken. max is the stress at the maximum elongation of the second stretchable wiring 22. The allowable stress σ2 of the second stretchable wiring 22 max For example, the following setting may be performed: the second stretchable wiring 22 is cut into a predetermined length in the extension direction, and then the relationship between the elongation and stress of the second stretchable wiring 22 is measured, and the allowable stress σ2 max Let it be the stress when the second stretchable wiring 22 is broken.

[0072] The first tensile load ratio being 1 or less means that the tensile load σ1 acting on the first stretchable wiring 21 is smaller than the allowable stress σ1 of the first stretchable wiring 21. max That is, if the structure of the first stretchable wiring 21 is selected, the first stretchable wiring 21 will not break, and the mechanical strength of the first stretchable wiring 21 is sufficient. Similarly, the second tensile load ratio is 1 or less, which means that the tensile load σ2 acting on the second stretchable wiring 22 is greater than the allowable stress σ2 of the second stretchable wiring 22. max That is, it means that if the structure of the second stretchable wiring 22 is selected, the second stretchable wiring 22 will not be broken, and the mechanical strength of the second stretchable wiring 22 is sufficient.

[0073] By satisfying the above formula (1) and formula (2), the first tensile load ratio and the second tensile load ratio are respectively 1 or less, so that the first stretchable wiring 21 and the second stretchable wiring 22 can be prevented from being broken. In addition, by satisfying the above formula (1) and formula (2), the shapes and materials of the first stretchable wiring 21 and the second stretchable wiring 22 corresponding to the displacement δ can be determined. Therefore, the displacement δ is within the range in which the stretchable device 1 will not be broken.

[0074] More preferably, the following formula is further satisfied.

[0075] σ1≤0.80×allowable stress σ1 of the first expansion / contraction wiring 21 max

[0076] σ2≤0.80×allowable stress σ2 of the second expansion / contraction wiring 22 max

[0077] According to this configuration, it is possible to more reliably suppress the first and second stretchable wirings 21 and 22 from being broken.

[0078] More preferably, the following formula is further satisfied.

[0079] σ1≤0.50×allowable stress σ1 of the first expansion / contraction wiring 21 max

[0080] σ2≤0.50×allowable stress σ2 of the second expansion / contraction wiring 22 max

[0081] According to this configuration, it is possible to more reliably suppress the first and second stretchable wirings 21 and 22 from being broken.

[0082] (Other preferred structures)

[0083] Preferably, the telescopic device further includes a connecting member 40 connecting the electronic component 30 and the first telescopic wiring 21, and when viewed from a direction (T direction) orthogonal to the main surface 111 of the telescopic base 11, the connecting member 40 does not overlap with the first end 221 in the extending direction of the second telescopic wiring 22. According to this structure, for example, when the connecting member 40 is solder, the thermal influence on the second telescopic wiring 22 when the connecting member 40 is formed can be suppressed.

[0084] Preferably, the first telescopic wiring 21 has a higher resistance to solder leaching than the second telescopic wiring 22. Solder leaching refers to a phenomenon in which metals in the telescopic wiring are eluted into the solder, thereby reducing the volume of the telescopic wiring. According to this structure, when the connecting member 40 is solder, the connection reliability between the first telescopic wiring 21 and the connecting member 40 can be improved.

[0085] As an example of a method for evaluating the resistance to solder leaching, for example, the expansion wiring is immersed in molten solder, and a graph showing the relationship between the immersion time and the amount of metal dissolved in the expansion wiring is generated. In addition, it can be evaluated that the greater the slope of the graph, the more likely solder leaching occurs, that is, the lower the resistance to solder leaching.

[0086] Preferably, the solubility (chemical etching) of the first telescopic wiring 21 in the resin is lower than the solubility (chemical etching) of the second telescopic wiring 22 in the resin. According to this structure, even when the covering layer 50 is, for example, a potting resin, and covers at least the connection portion between the electronic component 30 and the first telescopic wiring 21, it is possible to suppress the material of the first telescopic wiring 21 from dissolving in the covering layer 50.

[0087] The evaluation of the solubility of the telescopic wiring in the resin can be performed, for example, based on JIS K 7114: 2001 (ISO175: 1999). This test method completely immerses the test piece in the test liquid at a specified temperature and for a specified time. The mass of the test piece is measured before immersion and after being taken out of the test liquid and dried as needed. It can be evaluated that the greater the change in mass, the greater the solubility in the test liquid (the greater the chemical attack).

[0088] Preferably, the length L1 of the first stretchable wire 21 in the extending direction is shorter than the length L2 of the second stretchable wire 22. According to this structure, even when the first stretchable wire 21 is harder than the second stretchable wire 22, the influence on the stretchability of the stretchable device 1 can be suppressed.

[0089] Preferably, the Young's modulus (elastic coefficient) of the first telescopic wiring 21 is larger than the Young's modulus (elastic coefficient) of the second telescopic wiring 22. According to this structure, the first telescopic wiring 21 can be made harder than the second telescopic wiring 22. Therefore, the hardness can be softened step by step from the end of the electronic component 30 toward the second telescopic wiring 22. As a result, the stress that may be concentrated on the connection portion between the electronic component 30 and the first telescopic wiring 21 can be further alleviated.

[0090] Preferably, the thickness t1 of the first stretchable wiring 21 is greater than the thickness t2 of the second stretchable wiring 22. According to this structure, the resistance to solder leaching of the first stretchable wiring 21 can be further improved. In addition, since the allowable stress σ1 of the first stretchable wiring 21 can be increased, max , so the first tensile load ratio can be further reduced. In addition, since the gap between the electronic component 30 and the stretchable base 11 can be enlarged, the filling property of the cover layer 50 into the gap can be improved.

[0091] Preferably, the viscosity of the material of the first stretchable wiring 21 is greater than the viscosity of the material of the second stretchable wiring 22. According to this configuration, the thickness t1 of the first stretchable wiring 21 can be made greater than the thickness t2 of the second stretchable wiring 22 more reliably.

[0092] Preferably, the first telescopic wiring 21 is formed of a thermosetting material, the second telescopic wiring 22 is formed of a thermoplastic material, and the first end 221 of the second telescopic wiring 22 in the extending direction is stacked on the second end 212 in the extending direction of the first telescopic wiring 21. According to this structure, even when stress is applied to the telescopic device 1, it is possible to suppress interface peeling between the first telescopic wiring 21 and the second telescopic wiring 22, thereby further improving the mechanical strength of the telescopic device 1.

[0093] [Second embodiment]

[0094] The following reference Figure 3 and Figure 4 A telescopic device 1A according to the second embodiment will be described. Figure 3 It is a schematic perspective view of the telescopic device 1A. Figure 4 1A is a schematic top view partially showing the expansion and contraction device 1A. Figure 4 Observed from above Figure 3 The telescopic device 1A is different from the telescopic device 1 of the first embodiment in the configurations of the electronic component, the first telescopic wiring, and the second telescopic wiring.

[0095] like Figure 3 and Figure 4As shown in FIG. 1 , in this embodiment, the shape of the electronic component 30A is set to be a regular quadrangular prism. A plurality of external electrodes 32 are provided on the outer periphery of the lower surface of the electronic component 30A.

[0096] There are a plurality of first and second telescopic wires 21 and 22, respectively, and there are a plurality of telescopic wire groups consisting of the first telescopic wires 21 connected to the electronic component 30A and the second telescopic wires 22 connected to the first telescopic wires 21. Specifically, one first telescopic wire 21 is connected to one external electrode 32 of the electronic component 30A, and one second telescopic wire 22 is connected to the first telescopic wire 21. In addition, there are a plurality of telescopic wire groups consisting of the first telescopic wire 21 and the second telescopic wire 22 corresponding to each external electrode 32.

[0097] According to the above configuration, since there are a plurality of the expandable and contractible wire groups, stress concentrated on the connection portion between the electronic component 30A and the first expandable and contractible wires 21 can be further alleviated, and the mechanical strength of the expandable and contractible device 1A can be further improved.

[0098] Preferably, when observed from a direction (T direction) orthogonal to the main surface 111 of the telescopic substrate 11, each of the first telescopic wirings 21 in the plurality of telescopic wiring groups is arranged on the periphery of the electronic component 30A in a radial manner relative to the center C of the electronic component 30A, and in two adjacent telescopic wiring groups along the periphery of the electronic component 30A, an angle formed by an extension direction of the first telescopic wiring 21 in one telescopic wiring group and an extension direction of the first telescopic wiring 21 in the other telescopic wiring group is greater than 0° and is less than 90°.

[0099] Specifically explain, such as Figure 4 As shown in FIG. 1 , each of the first telescopic wires 21 in the first telescopic wire group P1, the second telescopic wire group P2, and the third telescopic wire group P3 is arranged on the periphery of the electronic component 30A in a radial manner relative to the center C of the electronic component 30A. In the first telescopic wire group P1 and the second telescopic wire group P2 adjacent to each other along the periphery of the electronic component 30A, an angle θ1 formed by the extending direction of the first telescopic wires 21 in the first telescopic wire group P1 and the extending direction of the first telescopic wires 21 in the second telescopic wire group P2 is greater than 0° and less than 90°. In the second telescopic wire group P2 and the third telescopic wire group P3 adjacent to each other along the periphery of the electronic component 30A, an angle θ2 formed by the extending direction of the first telescopic wires 21 in the second telescopic wire group P2 and the extending direction of the first telescopic wires 21 in the third telescopic wire group P3 is greater than 0° and less than 90°.

[0100] In this embodiment, the second expandable wirings 22 connected to the external electrode 32 provided on one side of the outer periphery of the electronic component 30A when viewed from the T direction extend in parallel with each other, but may be arranged obliquely to each other.

[0101] According to the above structure, since each of the first telescopic wirings 21 in the plurality of telescopic wiring groups is arranged on the periphery of the electronic component 30A in a radial manner relative to the center C of the electronic component 30A, the inter-wiring pitch WP and the inter-electrode pitch EP can be made different. In addition, the first telescopic wiring 21, which is softer than the electronic component 30A, can cover the periphery of the electronic component 30A. Therefore, even when tensile stress is applied to the telescopic device 1A, the stress that is concentrated on the connection portion between the electronic component 30A and the first telescopic wiring 21 can be further alleviated. In addition, no matter from which direction the tensile stress is applied to the telescopic device 1A, the shear deformation of the most affected part can be reduced, and the durability of the telescopic device 1A can be improved.

[0102] In addition, each embodiment is an example, and the present invention is not limited to each embodiment. In addition, each drawing is an example of a component, and does not limit the shape. In addition, partial replacement or combination of the structure shown in different embodiments can be performed.

[0103] In the above-described embodiment, there are a plurality of sets of the first stretchable wiring connected to the electronic component and the second stretchable wiring connected to the first stretchable wiring, but it is sufficient that there is at least one stretchable wiring set.

[0104] (Example 1)

[0105] The elongation of the first and second stretchable wirings with respect to stress was measured. Figure 5 Graphs G1 and G2 show the relationship between the elongation and stress of the first and second stretchable wirings. Graph G1 shows the results for the first stretchable wiring. Graph G2 shows the results for the second stretchable wiring.

[0106] like Figure 5 As shown in FIG. 1 , the first stretchable wiring is broken at an elongation of about 7%. The stress at this time is about 16 MPa. That is, the allowable stress of the first stretchable wiring is about 16 MPa. The second stretchable wiring is broken at an elongation of about 17%. The stress at this time is about 3 MPa. That is, the allowable stress of the second stretchable wiring is about 3 MPa.

[0107] The relationship between the thickness of the first stretchable wiring and the stretch ratio until the first stretchable wiring breaks was measured. Figure 6 This is a graph showing the thickness dependency of the relationship between the expansion / contraction ratio and the resistance value of the first expandable / contractable wiring.

[0108] like Figure 6 As shown, it is found that as the thickness of the first stretchable wiring increases, the stretching ratio until breaking increases. This is believed to be because as the thickness of the first stretchable wiring increases, the tensile load acting on the first stretchable wiring decreases, and the first tensile load ratio decreases.

[0109] (Example 2)

[0110] The range of the tensile load F at which the telescopic device can be used without breaking is calculated. The following calculation is an example, and the range of the tensile load F at which the telescopic device can be used without breaking may vary depending on the material and shape of the telescopic base material, the material and shape of the first telescopic wiring and the second telescopic wiring, the number and arrangement of electronic components, etc.

[0111] When the expansion ratio is assumed to be ε%, the tensile load F at which the expansion device 1 can be used without breaking is calculated by the following formula: The expansion ratio ε can be defined as the ratio of the displacement δ to the entire length of the expansion base before expansion.

[0112] The tensile load F at which the telescopic device 1 can be used without breaking is E×(ε / 100)×S

[0113] in,

[0114] E: Composite elastic modulus (composite elastic coefficient) of the stretchable base 11, the first stretchable wiring 21, and the second stretchable wiring 22

[0115] S: cross-sectional area of ​​the stretchable substrate 11 in a cross section perpendicular to the stretching direction

[0116] Figure 7 FIG. 1 is a schematic three-dimensional diagram partially showing a telescopic device 1B of Example 2. Figure 7 As shown, in the stretchable device 1B, the second stretchable wiring 22, the first stretchable wiring 21, the electronic component 30 and the first stretchable wiring 21 are connected in sequence to form a wiring / component group that is repeatedly connected along the A direction. In addition, there are multiple repeatedly connected wiring / component groups in a direction orthogonal to the A direction. Figure 7 The arrows indicate the direction of expansion and contraction.

[0117] Figure 7 The dotted line in the region AR represents an imaginary line connecting the midpoints of the adjacent electronic components 30. Figure 7 In FIG. 1 , the region AR is depicted as a square, but the region AR is not limited to a square. When viewed from the T direction, the center of gravity of the region AR overlaps with the electronic component 30. The area of ​​the region AR is the value obtained by dividing the area of ​​the entire substrate by the number of electronic components 30. EX When the expansion rate is expanded and contracted, if the synthetic elastic modulus of the occupied range is set as EEX , let the cross-sectional area of ​​the cross section perpendicular to the expansion and contraction direction be S EX , then the load dF of the occupied range is calculated using the following formula.

[0118] dF=E EX ×ε EX ×S EX

[0119] Assume that the area of ​​region AR is 10 mm 2 , the expansion rate ε EX It is assumed to be 20%. The elastic modulus (elastic coefficient, Young's modulus) of the stretchable substrate, the first stretchable wiring and the second stretchable wiring in the area AR, the cross-sectional area in the cross section perpendicular to the stretching direction, the length in the stretching direction and the synthetic elastic modulus are shown in Table 1. The synthetic elastic modulus is estimated based on the elastic modulus, cross-sectional area and length of each component. The stretchable substrate is assumed to be thermoplastic polyurethane (TPU). In Figure 7 , the length of the first telescopic wiring 21 in the telescopic direction is the sum of the length L1a and the length L1b. The length of the second telescopic wiring 22 in the telescopic direction is the sum of the length L2a and the length L2b. The length of the telescopic substrate in the telescopic direction is the sum of the length L1a, the length L1b, the length L2a, and the length L2b.

[0120]

Table 1

[0121]

[0122] When the cross-sectional area S EX When the cross-sectional area of ​​the stretchable substrate is approximated, the load dF is calculated as follows.

[0123] dF=E EX ×ε EX ×S EX =14MPa×0.2×(4×10 -1 mm 2 )=1.12N

[0124] The overall area of ​​the telescopic device 1B is 100 mm 2 In the case of , the load becomes 10 times, so the tensile load F that the telescopic device can be used without breaking is calculated to be a maximum of 10N.

[0125] (Example 3)

[0126] The relationship between the viscosity of the slurry and the thickness of the first retractable wiring formed was investigated using slurry as the material of the first retractable wiring. Since the first retractable wiring is in an island shape, it can be printed using a metal mask, and a slurry with a thixotropic property, i.e., the viscosity of the slurry, can be used by adding a thixotropic agent to increase the thixotropy. The slurry is printed using a metal mask to form the first retractable wiring.

[0127] Fig. 8A It is a figure which shows the coating shape of the slurry M1 which does not add a thixotropic agent. Figure 8B : is a diagram showing the coating shape of the slurry M2 to which a thixotropic agent is added. Fig. 8A As shown in FIG. 1 , in the slurry M1 without adding a thixotropic agent, the slurry spreads and has a thickness of about 25 μm. Figure 8B As shown, in the paste M2 to which the thixotropic agent is added, the paste does not spread and the thickness is about 50 μm. It is known that in the paste M2 to which the thixotropic agent is added and the viscosity is increased, the thickness of the first stretchable wiring can be increased.

[0128] In addition, a sample in which the thickness of the first telescopic wiring was 10 μm and a sample in which the thickness of the first telescopic wiring was 50 μm were prepared. Then, various changes were made to the thickness of the solder and the number of reflows for each sample, and the resistance to solder leaching was evaluated. The thickness of the solder was changed to 20 μm, 50 μm, 80 μm, 110 μm, and 140 μm. The number of reflows was changed to 1 time, 2 times, 3 times, 4 times, and 5 times. Solder leaching was confirmed in the sample in which the thickness of the first telescopic wiring was 10 μm, but solder leaching was not confirmed in the sample in which the thickness of the first telescopic wiring was 50 μm. It was found that the resistance to solder leaching was improved by increasing the thickness of the first telescopic wiring.

[0129] (Example 4)

[0130] The relationship between the stacking order of the first and second stretchable wirings and interface peeling was investigated. Figure 2 It was investigated whether the behavior of interface peeling is different in the case where the first end of the second telescopic wiring is stacked on the second end of the first telescopic wiring and in the case where the second end of the first telescopic wiring is stacked on the first end of the second telescopic wiring. A thermosetting material is used as the material of the first telescopic wiring. A thermoplastic material is used as the material of the second telescopic wiring. Table 2 shows the results when the first end of the second telescopic wiring is stacked on the second end of the first telescopic wiring. Table 3 shows the results when the second end of the first telescopic wiring is stacked on the first end of the second telescopic wiring. In Tables 2 and 3, for example, a numerical value recorded as "0.16 N / mm" represents the tensile load per unit width at the time of interface peeling.

[0131]

Table 2

[0132]

[0133]

Table 3

[0134]

[0135] As shown in Tables 2 and 3, when a thermosetting material is used as the material of the first telescopic wiring and a thermoplastic material is used as the material of the second telescopic wiring, cohesive failure occurs when the first end of the second telescopic wiring is stacked on the second end of the first telescopic wiring, and interface peeling occurs when the second end of the first telescopic wiring is stacked on the first end of the second telescopic wiring. Cohesive failure is not a state of interface peeling between the first telescopic wiring and the second telescopic wiring, but a state of failure inside either the first telescopic wiring or the second telescopic wiring. It was found that when a thermosetting material is used as the material of the first telescopic wiring and a thermoplastic material is used as the material of the second telescopic wiring, if the first end of the second telescopic wiring is stacked on the second end of the first telescopic wiring, interface peeling is suppressed and mechanical strength is improved.

[0136] The present disclosure includes the following aspects.

[0137] <1>

[0138] A telescopic device, wherein:

[0139] The telescopic device comprises:

[0140] a telescopic substrate having a major surface;

[0141] an electronic component disposed on the main surface of the telescopic substrate;

[0142] a first retractable wiring connected to the electronic component; and

[0143] a second telescopic wiring connected to the first telescopic wiring,

[0144] A first end portion of the first telescopic wiring in an extending direction is connected to the electronic component.

[0145] The second end portion of the first telescopic wiring in the extending direction is connected to the first end portion of the second telescopic wiring in the extending direction.

[0146] <2>

[0147] The stretchable device according to <1>, wherein the stretchable device satisfies the following formula:

[0148] σ1≤Allowable stress of the first expansion wiring

[0149] σ2≤Allowable stress of the second expansion wiring

[0150] in,

[0151] σ1=(δ×E1×S2×E2) / (L1×S2×E2+L2×S1×E1)

[0152] σ2=(δ×E1×S1×E2) / (L2×S1×E1+L1×S2×E2)

[0153] δ: The total displacement of the first and second telescopic wirings

[0154] L1: Length of the first telescopic wiring in the telescopic direction

[0155] L2: Length of the second telescopic wiring in the telescopic direction

[0156] S1: Cross-sectional area of ​​the first telescopic wiring in a cross section perpendicular to the telescopic direction

[0157] S2: Cross-sectional area of ​​the second telescopic wiring in a cross section perpendicular to the telescopic direction

[0158] E1: Elastic coefficient of the first expansion cable

[0159] E2: Elastic coefficient of the second telescopic wiring.

[0160] <3>

[0161] The stretchable device according to <2>, wherein the stretchable device further satisfies the following formula:

[0162] σ1≤0.80×allowable stress of the first expansion wiring

[0163] σ2≤0.80×allowable stress of the second expansion wiring.

[0164] <4>

[0165] The stretchable device according to <2>, wherein the stretchable device further satisfies the following formula:

[0166] σ1≤0.50×allowable stress of the first expansion wiring

[0167] σ2≤0.50×allowable stress of the second expansion wiring.

[0168] <5>

[0169] The telescopic device according to any one of <1> to <4>, further comprising a connection member connecting the electronic component and the first telescopic wiring.

[0170] The connecting member does not overlap with a first end portion in an extending direction of the second telescopic wiring when viewed from a direction perpendicular to the main surface of the telescopic base.

[0171] <6>

[0172] The stretchable device according to any one of <1> to <5>, wherein the first stretchable wiring and the second stretchable wiring each exist in plurality,

[0173] There are a plurality of extendable wiring groups including the first extendable wiring connected to the electronic component and the second extendable wiring connected to the first extendable wiring.

[0174] <7>

[0175] The telescopic device according to <6>, wherein each first telescopic wire in the plurality of telescopic wire groups is arranged on the periphery of the electronic component in a radial pattern relative to the center of the electronic component when viewed from a direction orthogonal to the main surface of the telescopic substrate,

[0176] In two adjacent retractable wiring groups along the outer periphery of the electronic component, an angle formed by an extending direction of the first retractable wiring in one retractable wiring group and an extending direction of the first retractable wiring in the other retractable wiring group is larger than 0° and less than 90°.

[0177] <8>

[0178] The stretchable device according to any one of <1> to <7>, wherein the first stretchable wiring has a higher resistance to solder leaching than the second stretchable wiring.

[0179] <9>

[0180] The stretchable device according to any one of <1> to <8>, wherein the solubility of the first stretchable wiring in the resin is lower than the solubility of the second stretchable wiring in the resin.

[0181] <10>

[0182] The stretchable device according to any one of <1> to <9>, wherein a length of the first stretchable wiring in the extending direction is shorter than a length of the second stretchable wiring in the extending direction.

[0183] <11>

[0184] The stretchable device according to any one of <1> to <10>, wherein the Young's modulus of the first stretchable wiring is larger than the Young's modulus of the second stretchable wiring.

[0185] <12>

[0186] The stretchable device according to any one of <1> to <11>, wherein a thickness of the first stretchable wiring is greater than a thickness of the second stretchable wiring.

[0187] <13>

[0188] The stretchable device according to any one of <1> to <12>, wherein the viscosity of the material of the first stretchable wiring is greater than the viscosity of the material of the second stretchable wiring.

[0189] <14>

[0190] The stretchable device according to any one of <1> to <13>, wherein the first stretchable wiring is formed of a thermosetting material.

[0191] The second retractable wiring is formed of a thermoplastic material.

[0192] The first end portion of the second stretchable wiring in the extending direction is stacked on the second end portion of the first stretchable wiring in the extending direction.

[0193] Description of Reference Numerals

[0194] 1, 1A, 1B, telescopic device; 11, telescopic substrate; 111, main surface; 21, first telescopic wiring; 211, first end of the first telescopic wiring; 212, second end of the first telescopic wiring; 22, second telescopic wiring; 221, first end of the second telescopic wiring; 222, second end of the second telescopic wiring; 30, 30A, electronic component; 31, 32, external electrodes; 40, connecting member; 50, covering layer; C, center; L1, length of the first telescopic wiring; L2, length of the second telescopic wiring; P1, P2, P3, telescopic wiring group; t1, thickness of the first telescopic wiring; t2, thickness of the second telescopic wiring; W1, width of the first telescopic wiring; W2, width of the second telescopic wiring.

Claims

1. A telescopic device, wherein: The telescopic device comprises: a telescopic substrate having a major surface; an electronic component disposed on the main surface of the telescopic substrate; a first retractable wiring connected to the electronic component; and a second telescopic wiring connected to the first telescopic wiring, A first end portion of the first telescopic wiring in the extending direction is connected to the electronic component. The second end portion of the first telescopic wiring in the extending direction is connected to the first end portion of the second telescopic wiring in the extending direction.

2. The telescopic device according to claim 1, wherein: The stretchable device satisfies the following formula: σ1≤Allowable stress of the first expansion wiring σ2≤Allowable stress of the second expansion wiring in, σ1=(δ×E1×S2×E2) / (L1×S2×E2+L2×S1×E1) σ2=(δ×E1×S1×E2) / (L2×S1×E1+L1×S2×E2) δ: The total displacement of the first and second telescopic wirings L1: Length of the first telescopic wiring in the telescopic direction L2: Length of the second telescopic wiring in the telescopic direction S1: Cross-sectional area of ​​the first telescopic wiring in a cross section perpendicular to the telescopic direction S2: Cross-sectional area of ​​the second telescopic wiring in a cross section perpendicular to the telescopic direction E1: Elastic coefficient of the first expansion cable E2: Elastic coefficient of the second telescopic wiring.

3. The telescopic device according to claim 2, wherein: The telescopic device also satisfies the following formula: σ1≤0.80×allowable stress of the first expansion wiring σ2≤0.80×allowable stress of the second expansion wiring.

4. The telescopic device according to claim 2, wherein: The telescopic device also satisfies the following formula: σ1≤0.50×allowable stress of the first expansion wiring σ2≤0.50×allowable stress of the second expansion wiring.

5. The telescopic device according to any one of claims 1 to 4, wherein: The telescopic device further includes a connecting member connecting the electronic component and the first telescopic wiring. The connecting member does not overlap with a first end portion in an extending direction of the second telescopic wiring when viewed from a direction perpendicular to the main surface of the telescopic base.

6. The telescopic device according to any one of claims 1 to 5, wherein: There are a plurality of the first retractable wiring and a plurality of the second retractable wiring, respectively. There are a plurality of extendable wiring groups including the first extendable wiring connected to the electronic component and the second extendable wiring connected to the first extendable wiring.

7. The telescopic device according to claim 6, wherein: When viewed from a direction perpendicular to the main surface of the stretchable substrate, each first stretchable wire of the plurality of stretchable wire groups is arranged on the periphery of the electronic component in a radial pattern relative to the center of the electronic component. In two adjacent retractable wiring groups along the outer periphery of the electronic component, an angle formed by an extending direction of the first retractable wiring in one retractable wiring group and an extending direction of the first retractable wiring in the other retractable wiring group is larger than 0° and less than 90°.

8. The telescopic device according to any one of claims 1 to 7, wherein: The first stretchable wiring has a higher resistance to solder leaching than the second stretchable wiring.

9. The telescopic device according to any one of claims 1 to 8, wherein: The solubility of the first stretchable wiring in the resin is lower than the solubility of the second stretchable wiring in the resin.

10. The telescopic device according to any one of claims 1 to 9, wherein: The length of the first telescopic wire in the extending direction is shorter than the length of the second telescopic wire in the extending direction.

11. The telescopic device according to any one of claims 1 to 10, wherein: The Young's modulus of the first stretchable wiring is larger than the Young's modulus of the second stretchable wiring.

12. The telescopic device according to any one of claims 1 to 11, wherein: The thickness of the first stretchable wiring is greater than the thickness of the second stretchable wiring.

13. The telescopic device according to any one of claims 1 to 12, wherein: The viscosity of the material of the first stretchable wiring is greater than the viscosity of the material of the second stretchable wiring.

14. The telescopic device according to any one of claims 1 to 13, wherein: The first retractable wiring is formed of a thermosetting material. The second retractable wiring is formed of a thermoplastic material. The first end portion of the second stretchable wiring in the extending direction is stacked on the second end portion of the first stretchable wiring in the extending direction.

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