Wiring board and method for manufacturing the same

Abstract

This wiring board 1 comprises a first substrate 10, a second substrate 20 configured from a different material than the first substrate 10, wiring 40 supported by the first substrate 10, and a terminal 50 that is supported by the second substrate 20 and that is connected to the wiring 40, the first and second substrates 10, 20 being positioned on the same side relative to the wiring 40, the first substrate 10 overlapping the wiring 40 but not overlapping the terminal 50 in plan view, and the second substrate 20 overlapping the terminal 50 in plan view.

Description

[Technical field]

[0001] The present invention relates to wiring boards such as stretchable wiring boards and molded wiring boards, and to methods for producing the same. For designated states in which incorporation by reference of literature is permitted, the contents of Patent Application No. 2020-190295, filed in Japan on November 16, 2020, are incorporated by reference into this specification and made a part of the description of this specification. [Background technology]

[0002] Stretchable flexible circuit boards capable of following the movements are used in the movable and bent parts of robots, medical and healthcare devices, etc. (See, for example, Patent Document 1.) Such stretchable flexible circuit boards include an insulating base material made of a thermoplastic elastomer having elasticity, and a wiring layer having wiring and terminals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-187380 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the stretchable flexible circuit board as described above, the wiring and terminals of the wiring layer are both formed on the same insulating base material. Since this insulating base material is made of a soft resin material such as polyurethane elastomer, when the terminals of the flexible circuit board are inserted into or removed from a connector of an external device, the soft insulating base material is significantly dented. This causes a problem that the terminals also become significantly dented in accordance with the dents in the insulating base material, which may result in poor contact between the terminals and the connector.

[0005] Furthermore, in a wiring board for molding (molded wiring board), a hard resin material such as ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin) is used as the insulating base material, rather than the soft resin material described above. Furthermore, the insulating base material made of ABS or the like is often thicker than the base material of the above-mentioned stretchable flexible circuit board. In such a molded wiring board, even if it is desired to arrange the molded wiring board in a state in which the portion (terminal portion) on which the terminals of the molded wiring board are formed is bent, there is a problem that the terminal portion may be difficult to bend because the terminals are formed on an insulating base material made of a hard and thick resin material.

[0006] An object of the present invention is to provide a wiring board having terminal portions suitable for different applications. [Means for solving the problem]

[0007] [1] A wiring board according to the present invention comprises a first substrate, a second substrate made of a material different from the first substrate, wiring supported by the first substrate, and a terminal supported by the second substrate and connected to the wiring, wherein the first and second substrates are arranged on the same side of the wiring, and the first substrate overlaps the wiring but does not overlap the terminal in a planar view, and the second substrate overlaps the terminal in a planar view.

[0008] [2] In the above invention, the wiring board may include a main body portion and a tail portion pulled out from the main body portion, the main body portion having the first substrate and the wiring, and the tail portion having the second substrate and the terminal.

[0009] [3] In the above invention, the second base material may include a first reinforcing plate and a second reinforcing plate bonded to the first reinforcing plate, and the first and second reinforcing plates may overlap the terminal in a planar view.

[0010] [4] In the above invention, the first reinforcing plate may be interposed between the terminal and the second reinforcing plate, the first reinforcing plate may be positioned in contact with the first base material, and the second reinforcing plate may be positioned at a distance from the first base material.

[0011] [5] In the above invention, the wiring board may satisfy the following formula (1): E1 <E2··· (1) In the above formula (1), E1 is the Young's modulus of the first substrate, and E2 is the Young's modulus of the second substrate.

[0012] [6] In the above invention, the wiring board may satisfy the following formula (2): T1>T2 (2) In the above formula (2), T1 is the thickness of the first base material, and T2 is the thickness of the second base material.

[0013] [7] In the above invention, the wiring board may further include a primer layer interposed between the first substrate and the wiring and between the second substrate and the terminal, and an overcoat layer formed on the primer layer so as to cover the wiring.

[0014] [8] In the above invention, the wiring and the main body of the terminal may be integrally formed.

[0015] [9] A method for manufacturing a wiring board according to the present invention includes a first step of preparing a release film, a first step of forming an overcoat layer on the release film, a second step of forming wiring on the overcoat layer and terminals on the release film connected to the wiring, a third step of forming a primer layer on the overcoat layer, the wiring, and the terminals, and a fourth step of attaching a first substrate and a second substrate made of a material different from the first substrate to the primer layer. Effect of the Invention

[0016] In the wiring board according to the present invention, the first substrate supporting the wiring and the second substrate supporting the terminals are made of different materials, which makes it possible to prevent the terminals from becoming indented, or to easily bend the area in which the terminals are formed, thereby providing a wiring board having terminals suitable for different applications. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a plan view showing a wiring board in an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing a state in which the tail portion of the wiring board is inserted into a connector in the embodiment of the present invention. [Figure 4] 4A to 4C are cross-sectional views illustrating a method for manufacturing a wiring board according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings, in which Fig. 1 is a plan view showing a wiring board in an embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0019] The wiring board 1 in this embodiment is a stretchable wiring board. This stretchable wiring board is used in places where stretchability is required in wearable devices such as biosensors and medical devices such as bioinformation monitors. Since wearable devices and medical devices are attached to clothing and accessories, it is necessary for the stretchable wiring board to sufficiently follow the bending of the human body. The use of the stretchable wiring board is not particularly limited as long as it requires stretchability.

[0020] The wiring board 1 includes a main body portion 1a and a tail portion 1b. As shown in FIG. 1, the main body portion 1a has a rectangular shape. The tail portion 1b has a strip shape with a narrower width (length along the Y direction in the figure) than the main body portion 1a. In this embodiment, the tail portion 1b is formed integrally with the main body portion 1a and is drawn out from the main body portion 1a. This tail portion 1b is used as a connection portion with an external device or another wiring board.

[0021] 2, wiring board 1 includes first substrate 10, second substrate 20, primer layer 30, wiring 40, terminals 50, and overcoat layer 60. First substrate 10, primer layer 30, wiring 40, and overcoat layer 60 are disposed in both body portion 1a and tail portion 1b, while second substrate 20 and terminals 50 are disposed in tail portion 1b.

[0022] First substrate 10 supports wiring 40 via primer layer 30. As shown in Fig. 1, first substrate 10 is disposed across from main body portion 1a to base 1c of tail portion 1b of wiring board 1. Like wiring board 1, first substrate 10 includes rectangular main body portion 10a and rectangular overlapping portion 10b that is smaller than main body portion 10a.

[0023] Main body portion 10a of first substrate 10 is formed over the entire main body portion 1a of wiring board 1, and overlapping portion 10b of first substrate 10 is disposed on the base 1c side of tail portion 1b of wiring board 1. Main body portion 10a and overlapping portion 10b are integrally formed, and overlapping portion 10b protrudes from main body portion 10a. The width of overlapping portion 10b (length along the Y direction in the figure) is narrower than the width of main body portion 10a.

[0024] Main body portion 10a of first substrate 10 overlaps with wiring 40 but does not overlap with terminal 50 in plan view (plan view when wiring board 1 is viewed from above or below (plan view when wiring board 1 is viewed from the normal direction to the main surface of wiring board 1 (Z direction in the examples of FIGS. 1 and 2)). Similarly, overlapping portion 10b of first substrate 10 also overlaps with wiring 40 but does not overlap with terminal 50 in plan view. Moreover, overlapping portion 10b is disposed on top of first reinforcing plate 21 (described later) of second substrate 20. It should be noted that first substrate 10 does not have to overlap second substrate 20. In other words, overlapping portion 10b does not have to be formed. First substrate 10 may have a tail portion drawn out from main body portion 10a, and the tail portion of first substrate 10 may be disposed on tail portion 1b of wiring board 1. In this case, the tip portion of the tail portion of first substrate 10 may overlap first reinforcing plate 21 of second substrate 20.

[0025] The first base material 10 has elasticity, and is composed of, for example, an elastic hot melt layer or adhesive layer. As materials for composing the hot melt layer and adhesive layer, for example, hot melt resin materials such as polyurethane, polyester, acrylic, styrene butadiene rubber, silicone, etc. can be used. The Young's modulus E1 of the first base material 10 is not particularly limited, but can be 0.1 MPa to 35 MPa (0.1 MPa ≦ E1 ≦ 35 MPa). In this case, the thickness T1 of the first base material 10 can be 25 to 100 μm (25 μm ≦ T1 ≦ 100 μm).

[0026] 2, the second base material 20 supports the wiring 40 and the terminal 50 via the primer layer 30. This second base material 20 and the above-mentioned first base material 10 are arranged on the same side (the -Y direction side in this example) with respect to the wiring 40. In this way, by arranging the first and second base materials 10, 20 on the same side, the wiring 40 and the terminal 50 can be integrally formed by a manufacturing method described later.

[0027] The second substrate 20 is disposed from the base 1c to the tip 1d of the tail portion 1b of the wiring board 1, and has a band shape having the same width as the tail portion 1b of the wiring board 1 in a plan view. As shown in FIG. 3, the second substrate 20 is disposed in the connection portion 12 that is sandwiched by the connector 100 when the terminal 50 is connected to the connector 100. The thickness of the connection portion 12 of the wiring board 1 is adjusted by the second substrate 20 to a thickness that conforms to the standard of the opening of the connector 100. The rigidity of the connection portion 12 of the wiring board 1 is made higher than the rigidity of other portions by the second substrate 20. In this embodiment, the second substrate 20 is not disposed in the main body portion 1a, but is not limited thereto. The second substrate 20 may be disposed up to the vicinity of the boundary of the tail portion 1b of the main body portion 1a.

[0028] In this embodiment, second base material 20 has a first reinforcing plate 21 and a second reinforcing plate 22. By making second base material 20 have a structure consisting of multiple layers (two layers in this example) in this manner, it becomes easier to adjust the thickness of second base material 20 during manufacturing of wiring board 1. Note that second base material 20 may be composed of only first reinforcing plate 21 and may not have second reinforcing plate 22.

[0029] 2, the first reinforcing plate 21 is attached to the lower surface 301 of the primer layer 30, and is interposed between the primer layer 30 and the second reinforcing plate 22. Moreover, the first reinforcing plate 21 overlaps with the wiring 40 and the terminal 50 in a plan view.

[0030] As shown in Figures 1 and 2, first reinforcing plate 21 has a band shape with the same width as the width of tail portion 1b of wiring board 1, and extends from overlapping portion 10b of first base material 10 to tip 1d of tail portion 1b of wiring board 1.

[0031] First reinforcing plate 21 is in contact with overlapping portion 10b of first base material 10, and rear end portion 21a of first reinforcing plate 21 is covered by overlapping portion 10b. Meanwhile, front end portion 21b of first reinforcing plate 21 is covered by second reinforcing plate 22. Here, rear end portion 21a refers to the end portion of first reinforcing plate 21 located on the base 1c side of tail portion 1b of wiring board 1, and front end portion 21b refers to the end portion of first reinforcing plate 21 located on the front end 1d side of tail portion 1b of wiring board 1.

[0032] The first reinforcing plate 21 is made of a material different from that of the first base material 10. In this embodiment, the first reinforcing plate 21 is made of a material harder than the first base material 10, and the Young's modulus E 2a is greater than the Young's modulus E1 of the first substrate 10 (E1 <E 2a Generally, as the Young's modulus increases, the rigidity also increases. Therefore, when such a relationship of Young's modulus is satisfied, the first reinforcing plate 21 is harder than the first base material 10. In addition, the Young's modulus E 2a is not particularly limited, but may be set to 1 GPa to 20 GPa (1 GPa ≦ E1 ≦ 20 GPa). 2a can be set to 50 to 200 μm (50 μm≦T 2a ≦200μm).

[0033] The first reinforcing plate 21 is not particularly limited, and may be, for example, an adhesive tape or a PET film. As the adhesive tape, for example, a polyester film having an acrylic adhesive layer on the main surface thereof may be used, and the first reinforcing plate 21 is disposed by attaching the acrylic adhesive layer to the primer layer 30. When a PET film is used, the PET film may be attached to the primer layer 30 with an adhesive or the like.

[0034] The second reinforcing plate 22 is attached to the lower surface 211 of the first reinforcing plate 21. The second reinforcing plate 22 is disposed along the tip 1d of the tail portion 1b, and covers the tip portion 21b of the first reinforcing plate 21. In addition, the second reinforcing plate 22 of this embodiment overlaps only the terminal 50 in a plan view, and does not overlap the wiring 40. Note that the second reinforcing plate 22 may overlap the wiring 40 in a plan view.

[0035] Second reinforcing plate 22 has a rectangular shape with the same width as that of tail portion 1b of wiring board 1. Moreover, the length of second reinforcing plate 22 along the extension direction of tail portion 1b of wiring board 1 (X direction in the figure) is shorter than the length of first reinforcing plate 21 along the extension direction, so that second reinforcing plate 22 covers only tip portion 21b of first reinforcing plate 21.

[0036] The second reinforcing plate 22 is spaced apart from the overlapping portion 10b of the first base material 10. Therefore, the lower surface 211 of the first reinforcing plate 21 is exposed to the outside in the gap located between the second reinforcing plate 22 and the first base material 10. By spaced apart the second reinforcing plate 22 and the first base material 10 as in this embodiment, the rigidity of the tail portion 1b is not increased too much by the second base material 20, and the tail portion 1b can be maintained in an easily bendable state.

[0037] The second reinforcing plate 22 is also made of a material different from that of the first base material. Although not particularly limited, the second reinforcing plate 22 may be made of an adhesive tape similar to that of the first reinforcing plate 21. Therefore, the second reinforcing plate 22 is also made of a material harder than the first base material 10, and the Young's modulus E 2b is greater than the Young's modulus E1 of the first substrate 10 (E1 <E 2b In this way, since the second base material 20 is composed of the first and second reinforcing plates 21, 22 which are harder than the first base material 10, the Young's modulus E2 of the second base material 20 is also larger than the Young's modulus E1 of the first base material 10, as shown in the following formula (1). E1 <E2··· (1) In the above formula (1), E1 is the Young's modulus of the first base material 10, and E2 is the Young's modulus of the second base material 20.

[0038] The thickness T of the second reinforcing plate 22 2b can be set to 100 to 250 μm (100 μm≦T 2a ≦250 μm). The thickness T 2b is the thickness T of the first reinforcing plate 21 2a The thickness may be the same as or different from that of the first and second electrodes.

[0039] The primer layer 30 is provided on the first and second substrates 10, 20 in the main body 1a and tail 1b of the wiring board 1. In this embodiment, the primer layer 30 is formed on the entire surfaces of the first and second substrates 10, 20. Therefore, the planar shape of the primer layer 30 is substantially the same as the overall planar shape of the first and second substrates 10, 20. Furthermore, the primer layer 30 has elasticity. The primer layer 30 may be omitted. In this case, the wiring 40 and the overcoat layer 60 are directly supported on the first substrate 10, and the wiring 40, the terminals 50 and the overcoat layer 60 are directly supported on the second substrate 20.

[0040] The primer layer 30 covers the lower and side surfaces of the wiring 40 and the terminals 50. The primer layer 30 functions as a buffer layer that prevents breakage of the wiring 40 and the terminals 50 when the wiring board 1 is stretched, and also functions as a waterproof layer. The material constituting the primer layer 30 is not particularly limited, but examples thereof include polyester resin, polyurethane resin, acrylic resin, and silicone resin. The Young's modulus E3 of the primer layer 30 is not particularly limited, but is preferably 0.1 to 10 MPa (0.1 MPa≦E3≦10 MPa). The thickness T3 of the primer layer 30 can be 10 to 50 μm (10 μm≦T3≦50 μm).

[0041] A plurality of wirings 40 (five in this example) are provided on primer layer 30. Wirings 40 are embedded in primer layer 30 so that their lower and side surfaces are covered, and their upper surfaces are covered by overcoat layer 60 and are not exposed to the outside. Wirings 40 are formed from tail portion 1b to main body portion 1a of wiring board 1, as shown in FIG.

[0042] The wiring 40 is made of conductive particles dispersed in a binder, and has elasticity. Here, the binder contained in the wiring 40 is made of an elastic material, which gives the wiring 40 elasticity, and it is preferable to use an elastomer as such a binder, and for example, acrylic rubber, urethane rubber, nitrile rubber, silicone rubber, fluororubber, a composite of two or more of these, etc. can be used.

[0043] The conductive particles may be made of metals such as gold, silver, platinum, ruthenium, lead, tin, zinc, bismuth, or alloys thereof, or non-metallic materials such as carbon. The conductive particles are preferably shaped like a flake or irregular shape.

[0044] Furthermore, the Young's modulus E4 of the wiring 40 is not particularly limited, but can be set to 10 to 200 MPa (10 MPa≦E4≦200 MPa).

[0045] A terminal 50 is formed on one end of the wiring 40. Like the wiring 40, the terminal 50 is embedded in the primer layer 30 so that its lower and side surfaces are covered, but it is not covered by the overcoat layer 60 and its upper surface is exposed to the outside. The terminal 50 can be used as a connection terminal with a connector 100 (see FIG. 3), and electrical continuity with electronic components and the like can be ensured via the connector 100.

[0046] This terminal 50 has a main body portion 51 and a protective layer 52. The main body portion 51 is integrally formed with the wiring 40. The main body portion 51 is composed of the same material as the wiring 40. Note that the terminal 50 may be composed only of the main body portion 51 and may not have the protective layer 52.

[0047] The protective layer 52 is disposed on the main body portion 51 and protects the main body portion 51 from contact with the connector 100. The material constituting the protective layer 52 is different from the material constituting the main body portion 51. Although not particularly limited, for example, carbon may be used as the conductive particles contained in the protective layer 52, and silver may be used as the conductive particles contained in the main body portion 51.

[0048] The overcoat layer 60 is disposed on the primer layer 30 so as to cover the wiring 40 and protects the wiring 40. In the present embodiment, the overcoat layer 60 is not formed on the entire surface of the primer layer 30 but is formed only on the portion where the wiring 40 is formed.

[0049] The overcoat layer 60 has elasticity similar to that of the primer layer 30. The material constituting the overcoat layer 60 is not particularly limited, and examples thereof include polyester, polyurethane, acrylic, and silicone.

[0050] The Young's modulus E6 of the overcoat layer 60 is preferably higher than the Young's modulus E3 of the primer layer 30 (E6>E3), and more preferably lower than the Young's modulus E4 of the wiring 40 (E6<E4). The Young's modulus E6 of such an overcoat layer 60 is preferably 5 to 100 MPa (5 MPa≦E6≦100 MPa). Further, the thickness T6 of the overcoat layer 60 can be 10 to 20 μm (10 μm≦T6≦20 μm).

[0051] Moreover, it is preferable that the material constituting the overcoat layer 60 is substantially the same as the material constituting the primer layer 30. In this case, the interface between the primer layer 30 and the overcoat layer 60 is barely visible, and the primer layer 30 and the overcoat layer 60 are substantially integrated.

[0052] Here, depending on how the wiring board is used, the temperature may change due to heating caused by Joule heat caused by current passing through the terminals and wiring, and the dissipation of the Joule heat, and the wiring board may undergo repeated thermal expansion and contraction. In this case, if the first substrate is present over the entire surface of the wiring board, including the portion where the terminals are formed, the portion of the first substrate that is clamped by the connector may become recessed due to repeated thermal expansion and contraction. Also, if there is no second substrate and the first substrate is present up to the tip of the tail portion, the first substrate is too soft to begin with, and the connector will not be connected to the terminal.

[0053] In contrast, in wiring board 1 of the present embodiment, first substrate 10 and second substrate 20 are made of different materials, and second substrate 20 is harder than first substrate 10. Then, only this hard second substrate 20 overlaps terminal 50 in a plan view. Therefore, as shown in FIG. 3, when connecting terminal 50 and connector 100, second substrate 20 is less likely to be dented, and terminal 50 can be made less likely to be dented. Therefore, the occurrence of poor contact between terminal 50 and connector 100 can be suppressed.

[0054] Next, a method for manufacturing wiring board 1 of the present embodiment will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view showing the method for manufacturing wiring board 1 of the present embodiment.

[0055] First, release film 200 is prepared as shown in Fig. 4(a). This release film 200 is a resin film that has been subjected to a release treatment, and is not particularly limited, but for example, a release-treated PET film can be used as release film 200. This release film 200 is peeled off in the process of Fig. 4(h) described later, and does not constitute a part of wiring board 1, so it is preferable to use an inexpensive film as release film 200.

[0056] Next, as shown in FIG. 4(b), an overcoat layer 60 having a predetermined pattern is formed on one of the main surfaces of the release film 200. At this time, the overcoat layer 60 is not formed in the region where the terminals 50 are to be formed. The overcoat layer 60 is formed by applying the material constituting the overcoat layer 60 described above onto the release film 200 and curing the applied material. As the application method, various application methods such as a screen printing method, a spray coating method, a bar coating method, a dipping method, and an inkjet method can be adopted. As the curing method, irradiation with energy rays such as ultraviolet rays and infrared laser light, heating, heating and cooling, drying, etc. can be adopted.

[0057] Next, as shown in FIG. 4(c), the terminal 50 and the wiring 40 are formed. The wiring 40 and the terminal 50 are formed by applying a conductive paste onto the release film 200 and the overcoat layer 60 and curing the paste. A specific example of the conductive paste is a conductive paste formed by mixing conductive particles, a binder, water or a solvent, and various additives. Examples of the solvent contained in the conductive paste are butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, dipropylene glycol monobutyl ether, diethylene glycol monoethyl ether, cyclohexanone, isophorone, and terpineol. The application method and curing method can be the same as those used when forming the overcoat layer 60.

[0058] In this embodiment, the wiring 40 and the main body 51 of the terminal 50 are made of the same material and are integrally formed. On the other hand, the protective layer 52 of the terminal 50 is made of a material different from that of the wiring 40 and the main body 51. Therefore, in this embodiment, for example, first, a carbon paste is applied and cured on the release film 200 to form the protective layer 52, and then a silver paste is applied and cured on the overcoat layer 60 and the protective layer 52, thereby forming the wiring 40 and the main body 51. The carbon paste that forms the protective layer 52 and the silver paste that forms the wiring 40 and the main body 51 may be cured simultaneously.

[0059] 4(d), the primer layer 30 is formed on the release film 200 so as to cover the wiring 40 and the terminal 50. The primer layer 30 is formed by applying the above-mentioned resin material and curing it. The application method and curing method can be the same as those used in forming the overcoat layer 60.

[0060] 4(e), a first reinforcing plate 21 is attached to the primer layer 30. Specifically, the above-mentioned adhesive tape is used, and the adhesive layer of the adhesive tape is attached to the primer layer 30, thereby forming the first reinforcing plate 21.

[0061] Next, as shown in FIG. 4(f), the first base material 10 is formed on the primer layer 30 and the first reinforcing plate 21. The first base material 10 can be formed by attaching a sheet-like hot melt adhesive to the primer layer 30 and the first reinforcing plate 21 using a thermal laminator or the like. The first base material 10 may also be formed by applying a thermoplastic hot melt adhesive onto the primer layer 30 and the first reinforcing plate 21. At this time, the hot melt adhesive may be heated and formed into any shape.

[0062] 4(g), the second reinforcing plate 22 is attached to the first reinforcing plate 21 so as not to come into contact with the first base material 10. Specifically, the above-mentioned adhesive tape is used, and the adhesive layer of the adhesive tape is attached to the first reinforcing plate 21, and then the second reinforcing plate 22 is attached to the first reinforcing plate 21 via the adhesive tape. Note that in this embodiment, the second reinforcing plate 22 is attached to the first reinforcing plate 21 after the first base material 10 is formed, but the present invention is not limited to this, and the second reinforcing plate 22 may be attached to the first reinforcing plate 21 before the first base material 10 is formed.

[0063] In the manufacturing method of wiring board 1 of the present embodiment, the smooth surface shape of release film 200 is transferred to the surfaces of the terminals and the surface of overcoat layer 60, so that the surfaces of both are smooth and the occurrence of steps at the boundaries between the two can be suppressed (made flush). As a result, when wiring board 1 is used in a wearable device or the like, the unevenness on the surface (upper surface) of wiring board 1 can be reduced to a level that does not cause a user to feel uncomfortable.

[0064] In addition, in this embodiment, the wiring board 1 is described as an elastic wiring board, but the present invention is not limited thereto. For example, the wiring board 1 may be a molded wiring board. The molded wiring board is a wiring board that is molded into a predetermined three-dimensional shape having a curved shape or the like by thermoforming or vacuum molding. This molded wiring board is incorporated into an electronic device or the like after molding.

[0065] When wiring board 1 is a molded wiring board, it differs from an elastic wiring board in that first substrate 10 is made of a material such as ABS or polycarbonate, which is harder than the material constituting second substrate 20, and in that first substrate 10 is thicker than second substrate 20.

[0066] When the first substrate 10 is made of ABS, polycarbonate, or the like, the Young's modulus of the first substrate 10 is approximately the same as that of the second substrate 20 made of an adhesive tape, PET, or the like. The thickness T1 of the first substrate 10 is greater than the thickness T2 of the second substrate 20, as shown in the following formula (2). Therefore, the second substrate 20 is more easily bent than the first substrate 10. T1>T2 (2)

[0067] In this embodiment, only the second base material 20 overlaps with the terminal 50 in a plan view, so that the portion of the tail portion 1b where the terminal 50 is formed can be easily bent.

[0068] Furthermore, when wiring board 1 is a molded wiring board, thickness T1 of first base material 10 can be 0.5 mm or more (0.5≦T1). If thickness T1 of first base material 10 is 0.5 mm or more, first base material 10 is less likely to break when molding wiring board 1. Thickness T1 of first base material 10 can be 5 mm or less.

[0069] Furthermore, when wiring board 1 is a molded wiring board, thickness T2 of second base material 20 can be 0.3 mm or less (T2≦0.3 mm). If thickness T2 of second base material 20 is 0.3 mm or less, flexibility of second base material 20 can be ensured, and the thickness in the vicinity of terminal 50 can be adjusted to a thickness suitable for connection with connector 100. Thickness T2 of second base material 20 can be 50 μm or more (50 μm≦T2).

[0070] As described above, wiring board 1 according to this embodiment can have terminal portions suitable for different applications.

[0071] The above-described embodiments are described for the purpose of facilitating understanding of the present invention, and are not described for the purpose of limiting the present invention. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0072] For example, in the above embodiment, first substrate 10 and second substrate are disposed in tail portion 1b of wiring board 1, but when wiring board 1 is a molded wiring board, the bottom layer of tail portion 1b may be composed of only the second substrate, which makes it easier to bend the entire tail portion 1b. [Explanation of symbols]

[0073] 1...Wiring board 1a…Main body 1b…Tail section 1c…Base 1d…Tip 10...First substrate 10a…Main body 10b…Overlapping part 20...Second substrate 21…First reinforcing plate 21a...Rear end 21b...Tip 211…Bottom surface 22…Second reinforcing plate 30…Primer layer 40…Wiring 50…Terminal 51...Main body 52...Protective layer 60…Overcoat layer 100…Connector 200...Release film

Claims

1. A first substrate; A second substrate made of a material different from the first substrate; A wiring supported by the first base material; a terminal supported by the second base material and connected to the wiring; the first and second base materials are disposed on the same side with respect to the wiring, the first base material overlaps the wiring but does not overlap the terminal in a plan view; the second base overlaps with the terminal in a plan view, The first substrate is composed of a hot melt layer or an adhesive layer, The wiring board further includes a primer layer interposed between the first substrate and the wiring and between the second substrate and the terminal.

2. A wiring board, A first substrate; A second substrate made of a material different from the first substrate; A wiring supported by the first base material; a terminal supported by the second base material and connected to the wiring; the first and second base materials are disposed on the same side with respect to the wiring, the first base material overlaps the wiring but does not overlap the terminal in a plan view; the second base overlaps with the terminal in a plan view, The wiring board includes: A main body portion, a tail portion extended from the main body portion, The main body portion has the first base material and the wiring, the tail portion includes the second base material and the terminal, The second substrate comprises: A first reinforcing plate; a second reinforcing plate bonded to the first reinforcing plate, the first and second reinforcing plates overlap with the terminal in a plan view, the first reinforcing plate is interposed between the terminal and the second reinforcing plate, the first reinforcing plate is disposed in contact with the first base material; the second reinforcing plate is disposed apart from the first base material, the second reinforcing plate does not overlap the first base material in a plan view, The wiring board further includes a primer layer interposed between the first substrate and the wiring and between the second substrate and the terminal.

3. 2. The wiring board according to claim 1, The wiring board includes: A main body portion, a tail portion extended from the main body portion, The main body portion has the first base material and the wiring, The tail portion includes the second substrate and the terminal.

4. The wiring board according to claim 1 or 3, The second substrate comprises: A first reinforcing plate; a second reinforcing plate bonded to the first reinforcing plate, The first and second reinforcing plates overlap the terminals in a plan view.

5. 5. The wiring board according to claim 4, the first reinforcing plate is interposed between the terminal and the second reinforcing plate, the first reinforcing plate is disposed in contact with the first base material; The second reinforcing plate is disposed apart from the first base material.

6. The wiring board according to any one of claims 1 to 5, The wiring board satisfies the following formula (1). E １ <E ２ ・・・ (1) In the above formula (1), E1 is the Young's modulus of the first substrate, and E2 is the Young's modulus of the second substrate.

7. The wiring board according to any one of claims 1 to 4, The wiring board satisfies the following formula (2). T １ >T ２ ・・・ (2) In the above formula (2), T1 is the thickness of the first base material, and T2 is the thickness of the second base material.

8. The wiring board according to any one of claims 1 to 7, an overcoat layer formed on the primer layer so as to cover the wiring.

9. The wiring board according to claim 2 or 5, A wiring board wherein the tail portion has a concave gap between the first base material and the second stiffening plate, the gap being defined by the first base material, the first stiffening plate, and the second stiffening plate.

10. A method for manufacturing a wiring board according to claim 1 or 2, comprising the steps of: A first step of preparing a release film; A first step of forming an overcoat layer on the release film; a second step of forming wiring on the overcoat layer and forming terminals connected to the wiring on the release film; a third step of forming a primer layer on the overcoat layer, the wiring, and the terminal; and a fourth step of attaching to the primer layer a first substrate made of a hot melt layer or an adhesive layer and a second substrate made of a material different from the first substrate.

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