Flexible wiring board, method for manufacturing flexible wiring board, electronic module, electronic unit, and electronic apparatus

Abstract

To provide a flexible wiring board that has a function superior to a conventional technique.SOLUTION: A flexible wiring board is provided with signal lines and a shield layer overlapping the signal lines in plan view, and has an insulating part on a side of the signal lines opposite to the side provided with the shield layer. The shield layer is provided with an opening. The shield layer has a first area having an open area ratio equal to or more than a predetermined value, and a second area having an open area ratio lower than the first area. The second area is arranged at a position overlapping the insulating part and the signal lines in plan view. The boundary between the first area and the second area is arranged at an interval with the insulating part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a flexible wiring board, a manufacturing method, an electronic module, an electronic unit, and an electronic device. [Background technology]

[0002] Electronic devices, such as mobile phones, smartphones, and digital cameras, are equipped with wiring boards that perform signal processing. Demand for even higher performance and smaller size is increasing, and flexible wiring boards (Flexible Circuits), which have signal wiring circuits formed on a flexible insulating film and are flexible and can be bent, are now being used for the wiring boards.

[0003] Patent Document 1 discloses a wiring board equipped with a shield having a predetermined opening pattern.

[0004] Patent Document 2 discloses a flexible cable equipped with a shield having a mesh structure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-077802 A [Patent Document 2] JP 2018-200779 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the characteristics required for wiring boards are increasing day by day, and more excellent functions are being demanded, but there are still some characteristics that cannot be satisfied. [Means for solving the problem]

[0007] A first means for solving the above problem is a flexible wiring board having a signal line, a shielding layer provided so as to overlap the signal line in a planar view, and an insulating portion on the side of the signal line opposite the side on which the shielding layer is provided, wherein the shielding layer has an opening, the shielding layer has a first region having an opening ratio equal to or greater than a predetermined value, and a second region having an opening ratio lower than that of the first region, the second region is positioned at a position overlapping the insulating portion and the signal line in a planar view, and the boundary between the first region and the second region is positioned at a distance from the insulating portion in a planar view.

[0008] A second means for solving the above problem is a flexible wiring board in which a signal line, an insulating layer, and a reinforcement layer are laminated in this order, the reinforcement layer having a second reinforcement portion and a first reinforcement portion having a higher rigidity than the second reinforcement portion, an end of the signal line in a first direction in which the signal line extends is a terminal portion at which the signal line is exposed, the first reinforcement portion is adjacent to the terminal portion and is provided on the insulating layer provided on the signal line, the second reinforcement portion is adjacent to the first reinforcement portion and is provided on the insulating layer provided on the signal line, the first reinforcement portion is provided in a region from the end of the insulating layer to five times the length of the terminal portion in the first direction, the second reinforcement portion is provided in a region from the end of the insulating layer in the first direction that is longer than five times the length of the terminal portion in the first direction, and the first reinforcement portion is provided continuously in a direction intersecting the first direction. Effect of the Invention

[0009] According to the present invention, it is possible to provide a flexible wiring board having superior functions to those of the prior art. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a top view of the electronic unit according to the first embodiment. [Diagram 2] FIG. 2 is an enlarged view of a main part of FIG. [Diagram 3] 2. (a) is a cross-sectional view taken along line AA in FIG. 2, (b) is a cross-sectional view taken along line BB in FIG. 2, and (c) is a cross-sectional view taken along line CC in FIG. [Figure 4] FIG. 1 is a schematic diagram of a system used to evaluate the transmission characteristics of flexible wiring boards of examples and comparative examples. [Diagram 5] FIG. 2 is a schematic diagram of a system used to evaluate the flexibility of the flexible wiring boards of the examples and comparative examples. [Figure 6] FIG. 11 is a top view of a wiring board according to a second embodiment. [Figure 7] FIG. 11 is a top view of a wiring board according to a third embodiment. [Figure 8] FIG. 13 is a top view of a wiring board according to a fourth embodiment. [Figure 9] FIG. 13 is a top view of a wiring board according to a fifth embodiment. [Figure 10] FIG. 13 is a top view of a wiring board according to a sixth embodiment. [Figure 11] FIG. 13 is a top view of a wiring board according to an eighth embodiment. [Figure 12] FIG. 4 is a top view of a wiring board according to Comparative Example 1. [Figure 13] FIG. 11 is a top view of a wiring board according to Comparative Example 2. [Figure 14] FIG. 1 is an explanatory diagram of a digital camera that is an image capturing device as an example of an electronic device according to an embodiment. [Figure 15] FIG. 13 is a top view of an electronic unit according to a third embodiment. [Figure 16] 15. (a) is a cross-sectional view taken along line AA in FIG. 15, (b) is a cross-sectional view taken along line BB in FIG. 15, and (c) is a cross-sectional view taken along line CC in FIG. [Figure 17] 11 is a top view of the wiring board according to Examples 7 to 12. FIG. [Figure 18] 11A and 11B are top views of wiring boards according to Comparative Examples 3 to 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below is one embodiment of the invention, and the present invention is not limited to this embodiment.

[0012] First Embodiment In wiring boards built into electronic devices, the number of wires arranged is increasing for high-density mounting. In addition, with an increase in the amount of information communication, the transmission speed of signals flowing through the wires is also increasing, and the amount of radiation noise generated from the wiring board is increasing. Patent Document 1 discloses a wiring board equipped with a shield having a predetermined opening pattern in order to reduce radiation noise while maintaining high-frequency signal transmission characteristics.

[0013] However, it is difficult to achieve both flexibility and high-frequency transmission characteristics when a shielding layer is provided as in Patent Document 1. The first embodiment provides a flexible wiring board that achieves both flexibility and high-frequency signal transmission characteristics.

[0014] Hereinafter, the wiring board 200 according to the first embodiment will be described with reference to FIG. 1, FIG. 2, and FIG. 3. FIG. 1 is a top view of an electronic unit 100 including the wiring board 200. The electronic unit 100 includes a circuit board 101, a circuit board 102, and a wiring board 200 that electrically connects the circuit board 101 and the circuit board 102. The circuit board 101 and the circuit board 102 are, for example, printed circuit boards. The wiring board 200 is a flexible wiring board, for example, a flexible printed wiring board. An article in which the wiring board 200 and at least one of the circuit board 101 and the circuit board 102 are connected to each other can be called an electronic module 10. For example, the electronic module 10 in which the wiring board 200 is connected to the circuit board 101 is prepared, and the wiring board 200 of the electronic module 10 is further connected to the circuit board 102, thereby forming the electronic unit 100. Also, an electronic device including the electronic unit 100 can be formed.

[0015] 1, wiring board 200 extends in the X direction, which is the longitudinal direction. Wiring board 200 has a plurality of signal lines 22 and a plurality of ground lines 133, and each signal line 22 and each ground line 133 extends in the X direction. The signal lines 22 and the ground lines 133 are arranged at intervals in the Y direction, which is the short side direction and intersects with the X direction. The Z direction, which is perpendicular to the X direction and the Y direction, is the thickness direction of wiring board 200. Wiring board 200 is flexible and can be bent and deformed.

[0016] In this embodiment, the signal lines 22 and the ground lines 133 are all arranged in the Y direction when viewed from the Z direction (in a plan view). However, it is sufficient that at least some of the signal lines 22 and the ground lines 133 are arranged in parallel in the Y direction when viewed in a plan view.

[0017] A connector 112 is mounted on wiring board 110 constituting circuit board 101. Connector 112 is electrically connected to semiconductor device 111 by a conductor pattern on wiring board 110. Similar to wiring board 110, a connector 122 is mounted on wiring board 120 constituting circuit board 102. Connector 122 is electrically connected to semiconductor device 121 by a conductor pattern on wiring board 120.

[0018] Insulating portion 16 is provided around connector 112 of wiring board 200. By providing insulating portion 16 and increasing the thickness, peeling of the solder and wiring pattern in the connector portion can be suppressed when the connector is inserted or removed.

[0019] Wiring board 110 and wiring board 120 are, for example, rigid wiring boards, and may be printed wiring boards (rigid printed wiring boards) including a resin substrate or a ceramic substrate.

[0020] With the above configuration, semiconductor device 111 and semiconductor device 121 are electrically connected to each other so as to be able to communicate with each other via wiring board 110, wiring board 200, and wiring board 120. In this case, the connection to wiring boards 110 and 120 may be made by directly connecting wiring board 200 to wiring boards 110 and 120 by soldering, without via connectors 112 and 122. Wiring board 110 and wiring board 200 may be directly connected by soldering, and wiring board 120 and wiring board 200 may be connected via a connector.

[0021] Wiring board 200 is provided with shield layer 15 for preventing EMI (Electromagnetic interference) caused by radiation noise resulting from electromagnetic radiation from signal line 22. Here, a case will be described in which shield layer 15 has a mesh shape, but the shape of shield layer 15 is not limited to this.

[0022] Insulating portion 16 is provided near the end of wiring board 200 to prevent wiring board 200 from being damaged when connectors 112, 122 are attached or detached. Insulating portion 16 is, for example, a reinforcing plate, a resin film made of polyimide or the like, an adhesive tape, etc. Insulating portion 16 is preferably formed of a material having a higher Young's modulus than base material 12, but may be formed by making a portion of base material 12 thicker.

[0023] FIG. 2 is an enlarged view of the main part of FIG. 1. As shown in FIG. 2, the shield layer 15 of this embodiment is provided with the openings 17, and is divided into an area 202 (second area), an area 201 (first area), and an area 202 (third area) in the +X direction according to the ratio of the area of ​​the openings 17 per unit area (hereinafter referred to as the aperture ratio). The unit area includes a part of the shield layer 15 and a part of the multiple openings 17. The area 201 is an area having a higher aperture ratio than a predetermined aperture ratio, and the area 202 is an area having a lower aperture ratio than the area 201. The boundary between the area 202 (second area) and the area 201 is the boundary 203, and the boundary between the area 201 and the area 202 (third area) is the boundary 204. The boundary 203 and the boundary 204 can also be said to be the end face of the second area. In this embodiment, the area 202 and the area 201 have different line widths, and the positions where the line width changes in the +X direction correspond to the boundaries 203 and 204. Even if there is no clear boundary between the region 202 and the region 201, the region 201 and the region 202 can be defined by the aperture ratio.

[0024] The shield layer 15 may not be provided between the region 201 and the region 202. In that case, the boundary 203 between the region 202 and the region 201 is the boundary between the region 202 and the region where the shield layer 15 is not provided.

[0025] In this embodiment, a region 202 of the shield layer 15 is provided at a position where the signal line 22 and the insulating portion 16 overlap in a planar view, and a region 201 of the shield layer 15 is provided at a position where the signal line 22 and the insulating portion 16 do not overlap in a planar view. In this way, by lowering the aperture ratio at the position where the signal line 22 and the insulating portion 16 overlap in a planar view, the electromagnetic coupling between the signal and the shield layer 15 becomes stronger in the region where the signal line 22 and the insulating portion 16 overlap in a planar view. When the signal flows through the region having the insulating portion 16, the electromagnetic field created by the signal can be unevenly distributed in the direction of the shield layer 15. This reduces the relative dielectric constant of the region where the signal line 22 and the insulating portion 16 overlap in a planar view, and the dielectric loss generated in the insulating portion 16 can be suppressed. In addition, by increasing the aperture ratio at the position where the signal line 22 and the insulating portion 16 do not overlap in a planar view, the covering area of ​​the shield layer 15 in the bending region can be reduced, and good flexibility can be obtained.

[0026] The aperture ratio of region 201 is preferably, for example, 60% or more, and more preferably 70% or more. If the aperture ratio of region 201 is less than 60%, flexibility may deteriorate. The aperture ratio of region 202 is preferably 50% or less, and more preferably 40% or less. If the aperture ratio of region 202 exceeds 50%, the electromagnetic field created by the signal may be insufficiently distributed, and good transmission characteristics may not be obtained. However, the aperture ratio is not limited to these values, and it is sufficient that the aperture ratio of region 201 is higher than the aperture ratio of region 202. For example, the aperture ratio of region 202 may be 0%, that is, no opening 17 may be provided.

[0027] Boundary 203 between region 201 and region 202 of shield layer 15 is preferably located closer to end surface 170 of insulating section 16 than boundary 204, which is an end surface of region 201 and perpendicular to signal line 22. Boundary 203 is a position where region 201 switches to region 202. Furthermore, boundary 203 is preferably located at a position that is 10% or less of the distance from end surface 170 to boundary 204. This allows the impedance of signal line 22 to change more gradually, thereby obtaining good transmission characteristics. In addition, the aperture ratio at the bent portion of wiring board 200 can be increased, thereby obtaining good flexibility. In this embodiment, boundary 204 is a position where region 201 switches to region 202 when proceeding in the X direction from boundary 203. However, if region 202 is provided on only one side of wiring board 200, boundary 204 overlaps the end of wiring board 200.

[0028] Next, a cross section of wiring board 200 will be described with reference to Fig. 3. Fig. 3(a) is a cross section taken along line AA in Fig. 2, Fig. 3(b) is a cross section taken along line BB in Fig. 2, and Fig. 3(c) is a cross section taken along line CC in Fig. 2.

[0029] Wiring board 200 has substrate (insulating substrate) 12 over the entire region in the X direction, coverlay 14 consisting of adhesive layer 14a and coating layer 14b, wiring layer 13, and shield layer 15. Wiring layer 13 has a plurality of signal lines 22 and ground lines 133 as described above. In addition, wiring board 200 has insulating section 16 under the substrate in a partial region. Substrate 12, coverlay 14, and insulating section 16 are made of materials having electrical insulation. Wiring layer 13 and shield layer 15 are made of materials having conductivity. Substrate 12, coverlay 14, wiring layer 13, and shield layer 15 are formed by extending in the X direction. Signal lines 22 and ground lines 133 constituting wiring layer 13 are arranged at intervals in the Y direction inside coverlay 14, but do not necessarily have to be arranged inside coverlay 14.

[0030] In FIG. 3(a), region 202 of shield layer 15 is provided at a position where insulating portion 16 and signal line 22 overlap in a plan view. In contrast, in FIG. 3(b), region 202 of shield layer 15 is provided at a position where insulating portion 16 and signal line 22 do not overlap in a plan view. By providing region 202 of shield layer 15 at a position where insulating portion 16 and signal line 22 do not overlap in a plan view, the impedance of signal line 22 can be changed more gradually, and good transmission characteristics can be obtained. In FIG. 3(c), region 201 of shield layer 15 is provided at a position where insulating portion 16 and signal line 22 do not overlap in a plan view. This makes it possible to increase the aperture ratio at the bent portion of wiring board 200, and therefore good flexibility can be obtained.

[0031] The line width (width when viewed from the Z direction) of the shield layer 15 in the region 201 is preferably smaller than the line width of the shield layer 15 in the region 202. This makes it possible to easily adjust the aperture ratio of the region 201 and the aperture ratio of the region 202. The line width of the shield layer 15 in the region 202 is preferably 1.5 times or more, and more preferably 2 times or more, the line width of the shield layer 15 in the region 201.

[0032] In addition, while FIG. 2 illustrates two of the multiple signal lines 22, the number of signal lines 22 in this embodiment is not limited to two, and the present invention can also be applied to three or more signal lines. The substrate 12 and the coverlay 14 are formed in a sheet shape. In this embodiment, the adhesive layer 14a is disposed between the substrate 12 and the covering layer 14b. The adhesive layer 14a has a function of adhering the substrate 12 and the covering layer 14b. If the coverlay 14 has an adhesive function, the adhesive layer 14a may be omitted.

[0033] Wiring having a bandwidth capable of transmitting the digital data signals to be handled is used for each signal line 22. In order to handle a larger amount of signal transmission, it is preferable to configure differential signal wiring in which a pair of signal lines 22 is one set among the multiple signal lines 22, as in this embodiment. Note that the multiple signal lines 22 may include wiring that transmits single-ended signals such as control signals and response signals.

[0034] When the electrical average length of the positive-phase signal and the negative-phase signal transmitted through the differential signal wiring is different, a mode conversion occurs in which a part of the differential signal changes to a common mode signal, and common mode noise is induced. When the common mode noise resonates on the wiring board, a large radiation noise occurs at the frequency of the common mode noise. In addition, with the increase in the capacity of communication data in recent years, a differential signal having a high transmission speed of Gbps order, for example, 5 Gbps (Giga Bits Per Second) or more, is transmitted through the differential signal wiring. Note that the relationship R=2f is established between the transmission speed R [bps] of the signal and the fundamental frequency f [Hz] of the signal. In general, the time change amount of the current flowing through the transmission line becomes large, so that the higher the frequency of the transmitted signal, the more radiation noise is generated. Since the generated radiation noise is close to the communication frequency band of the wireless communication device, when the wireless communication IC wirelessly communicates with an external device (such as a PC or a wireless router) through an antenna, the radiation noise may be superimposed on the communication data. Therefore, by providing the region 201 and the region 202 as in this embodiment, the wiring board 200 can be made to have both flexibility and high-frequency signal transmission characteristics.

[0035] The interval between the signal lines 22 is preferably larger than the distance between the signal lines 22 and the shield layer 15. This allows the electromagnetic field created by the signal to be biased toward the shield layer 15 in the region where the insulating portion 16 is formed, and good transmission characteristics can be obtained. Note that the multiple signal lines 22 may include wiring that transmits single-ended signals such as control signals and response signals. Here, the distance between the signal lines 22 refers to the distance between the signal lines 22 in one pair when the signal lines 22 are differential signal wiring.

[0036] The method of forming the signal line 22 is not particularly limited, but the signal line 22 can be formed by, for example, laminating metal foil, metal plating, inkjet process, or the like. When using copper foil as the metal foil, a film laminated with an adhesive or the like can be used to form the required transmission line pattern by a photolithography / etching process. When using an inkjet process, the required pattern can be drawn with a polymer ink containing metal particles, and the pattern can be baked at a temperature equal to or lower than the glass transition point (Tg) of the substrate 12 to form the signal line 22. The thickness of the signal line 22 is not particularly limited, but is preferably, for example, 0.1 μm or more and 20 μm or less.

[0037] The configuration of wiring board 200 will now be described in more detail.

[0038] The insulating part 16 can be made of plastic and / or insulating resin. Examples of the plastic include epoxy resin, imide resin, phenol resin, cyanate resin, etc. The insulating part 16 may contain a filler. Examples of the filler include silica, kaolin, talc, alumina, etc. Also, these may be mixed. In addition to the filler, a glass cloth using glass fiber bundles, carbon fiber bundles, polyester fiber bundles, nylon fiber bundles, aramid fiber bundles, and other fibers may be used. The method of forming the insulating part 16 under the base material 12 is not particularly limited, but an adhesive layer (not shown) is used. An adhesive or adhesive film can be used as the adhesive layer. Examples of the adhesive include acrylic resin, urethane resin, polyester resin, polyamide resin, ethylene butyl alcohol resin, ethylene vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, etc. Examples of the adhesive layer and the like can be used. Examples of the adhesive layer and the like include normal printing methods such as offset printing, gravure printing, and screen printing, and coating methods such as gravure coating, roll coating, and comma coating. Also, an adhesive film can be laminated under the substrate 12 as the adhesive layer. For example, an unstretched polypropylene film can be used as the adhesive film, and the film can be laminated by a dry lamination method. The thickness of the insulating part 16 in the Z direction is preferably 20 μm or more in order to obtain sufficient strength when inserting and removing the connector. Also, the insulating part 16 preferably has a hardness (Young's modulus) sufficient to reinforce the wiring board 200, and is preferably lower than the flexibility of the wiring board 200. Also, the insulating part 16 preferably has a higher Young's modulus than the substrate 12, adhesive layer 14a, coating layer 14b, and shield layer 15 that constitute the wiring board 200. The thickness of the insulating part 16 is preferably thicker than the substrate 12 and shield layer 15, but is not limited thereto.

[0039] A shielding layer 15 is provided on the coverlay 14. The method for manufacturing the shielding layer 15 is not particularly limited, but it is preferable to directly pattern it by various printing methods such as screen printing and inkjet printing. Alternatively, a conductive film may be patterned by a photolithography / etching process. The shielding layer 15, which has been processed into a predetermined shape by die cutting or braiding, may be directly attached.

[0040] Furthermore, methods for forming the shield layer 15 on the coverlay 14 include subtractive methods, electroless plating methods, electrolytic plating methods, and physical vapor deposition methods such as vacuum deposition and sputtering methods. Also, a method of bonding conductive fibers, or a screen printing method can be used. Metals constituting the shield layer 15 include copper, aluminum, nickel, iron, gold, silver, platinum, tungsten, chromium, titanium, tin, lead, and palladium, and one or more of these may be combined. Among these, silver or copper is preferred from the viewpoints of conductivity and low cost.

[0041] The thickness of shield layer 15 is preferably 1 μm or more, and more preferably 5 μm or more. If the thickness is less than 1 μm, there is a risk that sufficient bending resistance cannot be obtained. If the thickness of shield layer 15 is 20 μm or less, the thickness of wiring board 200 can be made thinner, and therefore a wiring board 200 with higher flexibility can be provided. The surface resistance value of shield layer 15 is preferably 1 Ω / □ or less, and more preferably 0.1 Ω / □ or less.

[0042] The shield layer 15 in this embodiment has a plurality of openings arranged continuously along a predetermined direction. The shape of the openings is not particularly limited. Various shapes such as a rhombus, an ellipse, a rectangle, a hexagon, or a slit formed to extend in the Y direction can be formed as necessary. A shape in which a plurality of shapes are selected and arranged from among these shapes may also be used. Among these, polygons such as a square or a hexagon are preferable. If the openings are shaped like a polygon, the variation in the width of the non-openings can be suppressed, and the return path of the radiation noise can be made uniform, thereby more efficiently suppressing the radiation noise.

[0043] The substrate 12, the adhesive layer 14a, and the coating layer 14b will be described in detail below.

[0044] The material of the base material 12, which is an insulating substrate, is preferably a resin. Examples of the resin include polyimide-based resins such as polyimide, polyamide, and polyamideimide, thermosetting resins such as epoxy, and thermoplastic resins such as liquid crystal polymers. Among these, polyimide or liquid crystal polymers are preferable. Polyimide has excellent heat resistance and mechanical properties, and is easily available commercially. In addition, liquid crystal polymers have a low relative dielectric constant, making them suitable for high-speed signal transmission applications, and have low moisture absorption and excellent dimensional stability.

[0045] The thickness of the base material 12 is not particularly limited, but is preferably in the range of 10 μm to 100 μm. If the thickness is less than 10 μm, the distance between the signal line 22 and the shield layer 15 becomes short, and the characteristic impedance value may become excessively large. On the other hand, if the thickness exceeds 100 μm, the rigidity of the resin becomes high, and there is a risk of insufficient flexibility. More preferably, the thickness is in the range of 12 μm to 75 μm.

[0046] Next, the adhesive layer 14a will be described in detail. The adhesive layer 14a is an adhesive layer provided between the base material 12 (insulating substrate) and the covering layer 14b and the signal line 22. That is, the adhesive layer 14a is a cured product of an adhesive. The adhesive layer 14a preferably has high electrical insulation. Examples of adhesives used to form the adhesive layer 14a include acrylonitrile butadiene rubber (NBR)-based adhesives, polyamide-based adhesives, polyester-based adhesives, acrylic-based adhesives, polyester polyurethane-based adhesives, and silicone-based adhesives.

[0047] It is preferable that the adhesive layer 14a is capable of sufficiently covering the signal line 22, which is a transmission line, and is smooth. Therefore, it is preferable that the thickness of the adhesive layer 14a in the Z direction is 2 μm or more and 50 μm or less. If the thickness of the adhesive layer 14a is 2 μm or more, the adhesive can be sufficiently embedded between the signal lines 22, and the adhesive layer 14a can adhere firmly. If the thickness of the adhesive layer 14a is 50 μm or less, it is possible to prevent the adhesive from seeping out to the side from between the base material 12 and the covering layer 14b. Furthermore, from the above viewpoints, it is more preferable that the thickness of the adhesive layer 14a in the Z direction is 5 μm or more and 30 μm or less.

[0048] The method for forming the adhesive layer 14a is not particularly limited, but examples thereof include a method in which a sheet-like adhesive is bonded and cured, and a method in which a liquid adhesive is applied using a dispenser or printing method, etc., and then cured by heat or ultraviolet rays.

[0049] Next, the covering layer 14b will be described in detail. Plastic and / or insulating resin can be used as the covering layer 14b. The plastic used for the covering layer 14b includes so-called engineering plastic. That is, other plastics used for the covering layer 14b include, for example, polypropylene, cross-linked polyethylene, polyester, polybenzimidazole, polyamide, polyimide, polyimideamide, and polyetherimide. In addition, the plastic used for the covering layer 14b includes, for example, polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), and polyether ether ketone (PEEK). From the viewpoint of low cost, it is preferable to use a polyester film. From the viewpoint of excellent flame retardancy, it is preferable to use a polyphenylene sulfide film. In addition, when heat resistance is required, it is preferable to use an aramid film or a polyimide film.

[0050] The insulating resin used in the coating layer 14b may be any resin having electrical insulation properties, such as a thermosetting resin or an ultraviolet curing resin. Examples of the thermosetting resin include phenolic resin, acrylic resin, epoxy resin, melamine resin, silicone resin, and acrylic-modified silicone resin. Examples of the ultraviolet curing resin include epoxy acrylate resin, polyester acrylate resin, and their methacrylate-modified products. The curing form may be any of heat curing, ultraviolet curing, and electron beam curing. In addition, other additives such as color pigments, flame retardants, antioxidants, lubricants, dust prevention agents, and curing accelerators may be added as necessary.

[0051] The method of forming the coating layer 14b is not particularly limited, but the coating layer 14b can be coated on the adhesive layer 14a by the following method. For example, a solution obtained by dissolving an insulating resin in a solvent can be applied by a gravure coating method, a kiss coating method, a die coating method, a blade method, a roll coating method, a knife coating method, a spray coating method, a bar coating method, a spin coating method, or a dip coating method. The solvent can be appropriately selected depending on the type of resin used. For example, ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohexanone, and alcohol-based solvents such as methanol, ethanol, propanol, ethylene glycol, glycerin, and propylene glycol monomethyl ether can be used. In addition, acids such as acetic acid, amide-based solvents such as formamide, dimethylacetamide, and N-methylpyrrolidone, nitrile-based solvents such as acetonitrile and propylonitrile, and ester-based solvents such as methyl acetate and ethyl acetate can be used. Carbonate-based solvents such as dimethyl carbonate and diethyl carbonate can also be used. When applying, a heating or drying process may be provided to volatilize the solvent as necessary. For heating and drying, a heating device and a drying device such as a hot air dryer or an infrared heater can be used, and the heating temperature, drying temperature, heating time, and drying time can be appropriately selected.

[0052] The thickness of the coating layer 14b in the Z direction is preferably 5 μm or more and 50 μm or less. When the thickness of the coating layer 14b in the Z direction is 5 μm or more, sufficient strength can be ensured in the coating layer 14b. When the thickness of the coating layer 14b in the Z direction is 50 μm or less, the sliding properties and bending properties are improved. Furthermore, from the above viewpoints, the thickness of the coating layer 14b in the Z direction is more preferably 10 μm or more and 30 μm or less. In addition, the volume resistivity of the coating layer 14b is preferably 10 9 Ω·cm or more is preferable, and 10 13 It is more preferable that the resistivity is Ω·cm or more.

[0053] <Example> The present invention will now be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. The evaluation method (measurement method) of the wiring board in the present invention is as follows.

[0054] The evaluation methods for the wiring boards according to the examples and comparative examples will be described below.

[0055] (1) Transmission characteristics evaluation (eye pattern) The output waveform characteristics of the flexible printed wiring board were evaluated using the system configuration shown in FIG. 4. This system is composed of a pair of connection boards 31, a signal generator 32, and an oscilloscope 33. The signal generator 32 was an M8041A manufactured by Agilent Technologies. The oscilloscope 33 was an 92504A manufactured by Agilent Technologies. The connection board 31 has an input terminal and an output terminal, and the wiring board 200 to be measured was connected between the pair of connection boards 31 in a linear state suspended in the air. Furthermore, the signal generator 32 was connected to one of the connection boards 31, and a pseudo-random signal of PRBS (Pseudo-Random Binary Sequence) 23 was input at a bit rate of 10.6 Gbps. The amplitude of the input signal was 250 mV / side (differential 500 mV). The other connection board 31 was connected to an oscilloscope 33, and the opening amplitude of the signal eye pattern output from the connection board 31 was observed. The measurements were carried out in an atmosphere with a temperature of 25° C. and a relative humidity of 30 to 50%. The evaluation criteria were as follows. A (excellent): Aperture amplitude 120mV or more B (Good): Opening amplitude 90mV or more, less than 120mV C (not acceptable): Opening amplitude less than 90mV

[0056] (2) Bending load measurement As shown in Fig. 5, wiring board 200 was placed on stainless steel plate 41 with a thickness of 1 mm, and bent so that the bending line was parallel to the board width direction with a bending radius of 3 mm. The load at this time was measured by pressing load measuring device 42 (IMADA ZTS-2N) from above. The evaluation criteria were as follows: A (Excellent): Bending load less than 10gf B (Good): Bending load 10gf or more, less than 15gf C (unacceptable): bending load 15gf or more

[0057] Example 1 The wiring board 200 shown in FIG. 2 was produced. A polyimide film (Kapton 100H manufactured by DuPont-Toray Co., Ltd.) having a thickness of 25 μm was prepared as the substrate 12. A copper foil having a thickness of 12 μm was laminated on the substrate 12 as the wiring layer 13, and a signal line 22 and a ground line 133 having a total length of 100 mm were formed by etching. The signal lines 22 were formed as a pair of differential signal wirings with a distance between the signal lines 22 of 55 μm and a width of 205 μm for each pair of signal lines 22. Meanwhile, the ground lines 133 were arranged on both sides of the pair of signal lines 22 with a width of 100 μm and a distance of 150 μm between the adjacent signal lines 22, thereby obtaining the wiring layer 13. From the viewpoint of the insulation of the signal lines 22, the substrate 12 was prepared so that the ground lines 133 located at both ends of the wiring board 200 were located 500 μm inward from the outside of the wiring board 200.

[0058] Next, the coverlay 14 is formed on the wiring layer 13. An adhesive with a thickness of 25 μm was used as the adhesive layer 14a, and a coverlay with a thickness of 15 μm (CEAM0525KA manufactured by Arisawa Manufacturing Co., Ltd.) was used as the coating layer 14b, with a total thickness of 37.5 μm. Next, the shield layer 15 was formed on the coverlay 14. The shield layer 15 was formed by printing a silver paste (product name: DD-1630L-245) manufactured by Kyoto Elex Co., Ltd. with a screen printer (MT-320T manufactured by Micro-Tec Co., Ltd.) to a thickness of 5 μm. At this time, the shield layer 15 is formed so that it is printed in two patterns, an area 201 and an area 202, by adjusting the opening pattern of the screen printing plate. The boundary 203 between the area 201 and the area 202 is set to be located 5 mm toward the boundary 204 side from the end face 170 of the insulating part 16 across which the signal line 22 crosses in the pattern view. The area closer to boundary 204 than boundary 203 was designated as region 201, and the area opposite boundary 204 was designated as region 202. Region 201 was formed to have a diamond mesh pattern with a line width of 58 μm and openings 17 of 2000 μm in the X direction and 500 μm in the Y direction, and the longitudinal direction of openings 17 was parallel to signal line 22. Region 202 was formed to have a diamond mesh pattern with a line width of 200 μm and openings 17 of 2000 μm in the X direction and 500 μm in the Y direction, and the longitudinal direction of openings 17 was parallel to signal line 22. Finally, a reinforcing plate (FR-4) made of glass epoxy with a thickness of 400 μm and adhesive 60 μm was attached to the bottom of base material 12 up to a position 20 mm in the X direction to form insulating section 16, and wiring board 200 of Example 1 was obtained.

[0059] Example 2 As shown in FIG. 6, boundary 203 between region 201 and region 202 of shielding layer 15 was formed so as to overlap end face 170 of insulating portion 16 across which signal line 22 crosses in a pattern plan view, and the rest was formed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 2.

[0060] Example 3 As shown in FIG. 7, region 202 of shield layer 15 was formed in a solid pattern without openings 17 in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 3.

[0061] Example 4 As shown in FIG. 8, boundary 203 between regions 201 and 202 of shielding layer 15 was formed so as to be located 8 mm toward boundary 204 from end face 170 of insulating portion 16, and the rest was formed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 4.

[0062] Example 5 As shown in FIG. 9, region 201 of shielding layer 15 was formed in a stripe shape parallel to the Y direction with a line width of 50 μm and a line spacing of 200 μm, and region 202 was formed in a solid pattern without openings 17. Except for this, the wiring board 200 of Example 5 was formed in the same manner as in Example 1.

[0063] Example 6 As shown in FIG. 10, region 201 of shielding layer 15 was formed in a square mesh shape with a line width of 50 μm and an opening 17 with a side length of 425 μm, and region 202 was formed in a square mesh shape with a line width of 176 μm and an opening 17 with a side length of 425 μm. Except for this, the wiring board 200 of Example 6 was formed in the same manner as in Example 1.

[0064] Example 7 Wiring board 200 of Example 7 was obtained by forming it in the same manner as in Example 1, except that the aperture ratio of region 202 was set to 70%.

[0065] Example 8 As shown in FIG. 11 , boundary 203 between regions 201 and 202 of shielding layer 15 was formed so as to be located 5 mm away from end face 170 of insulating portion 16 on the opposite side of boundary 204, and the rest was formed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 8.

[0066] Comparative Example 1 12, region 201A was formed in a diamond-shaped mesh pattern with a line width of 58 μm over the entire region of shield layer 15A, and opening 17A of 2000 μm in the X direction and 500 μm in the Y direction. Insulating portion 16A was formed so as to overlap a portion of region 201 in a plan view, and opening 17A was formed so that the longitudinal direction of opening 17A was parallel to signal line 22A and ground line 133A. The rest of the process was formed in the same manner as in Example 1, thereby obtaining wiring board 200A of Comparative Example 1.

[0067] Comparative Example 2 13, region 201A was formed in which the entire area of ​​shield layer 15 had a line width of 200 μm and openings 17 had a diamond-shaped mesh pattern of 2000 μm in the X direction and 500 μm in the Y direction. Insulating portion 16A was formed so as to overlap with part of region 201 in a plan view, and openings 17 were formed so that the longitudinal direction of openings 17 was parallel to signal line 22 and ground line 133A. The rest of the process was formed in the same manner as in Example 1, thereby obtaining wiring board 200A of Comparative Example 2.

[0068] (Evaluation Results) The evaluation results of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in Table 1. All of wiring boards 200 of Examples 1 to 8 had good transmission characteristics and flexibility.

[0069] Comparing Example 1 and Example 2, in Example 1, the boundary 203 between the region 201 and the region 202 is located closer to the boundary 204. Therefore, it is possible to suppress the reflection loss of the signal by changing the impedance of the signal line 22 more gradually, and it is possible to obtain better transmission characteristics. Comparing Example 1 and Example 4, the result is that Example 1 has higher flexibility. This is thought to be because the boundary 203 in Example 4 is located closer to the boundary 204 than in Example 1, and by shifting the boundary 203 closer to the boundary 204, the covering area of ​​the shield layer 15 at the bent portion increases, and the flexibility deteriorates.

[0070] In Comparative Example 1, the shield layer 15 is configured in a diamond-shaped mesh shape with an opening ratio of 80% uniformly over the entire surface. With such a configuration, as described above, the uneven distribution of the signal electromagnetic field by the shield layer 15 becomes insufficient, and the dielectric loss becomes excessively large in the region of the insulating part 16, resulting in deterioration of the transmission characteristics. In Comparative Example 2, the shield layer 15 is configured in a diamond-shaped mesh shape with an opening ratio of 50% uniformly over the entire surface. With such a configuration, not only does the coverage area of ​​the shield layer 15 increase and the flexibility deteriorate, but the uneven distribution of the signal electromagnetic field becomes excessively large over the entire signal wiring, resulting in increased resistance loss and deterioration of the transmission characteristics.

[0071] [Table 1]

[0072] <Second embodiment> Next, a digital camera 600, which is an imaging device, will be described with reference to FIG. 14 as an example of an electronic device using any of the wiring boards shown in the first embodiment.

[0073] The digital camera 600 is a lens-interchangeable digital camera, and includes a camera body 601. A lens unit (lens barrel) 602 including a lens is detachably attached to the camera body 601. The camera body 601 includes a housing 611, an electronic unit 100, and a wireless communication unit 150. The electronic unit 100 and the wireless communication unit 150 are stored inside the housing 611. In the case of an imaging device, the electronic unit 100 is an imaging unit.

[0074] Electronic unit 100 includes circuit board 101, circuit board 102, and wiring board 200 that electrically connects circuit board 101 and circuit board 102. Circuit board 101 is an example of a first circuit board. Circuit board 102 is an example of a second circuit board. By using wiring board 200 to connect circuit board 101 and circuit board 102, the wiring structure can be made lighter than a coaxial cable. Here, the wiring board previously described in the first embodiment is used as wiring board 200.

[0075] Circuit board 101 includes wiring board 110 and semiconductor device 111 mounted on wiring board 110. Circuit board 102 includes wiring board 120 and semiconductor device 121 mounted on wiring board 120. Semiconductor device 111 and semiconductor device 121 are examples of electronic components mounted on wiring boards 110 and 120. The electronic components mounted on wiring boards 110 and 120 may be an imaging device, a computing device, a display device, a communication device, a storage device, a power supply device, or a computing device. The electronic components mounted on wiring boards 110 and 120 are not limited to active components, and may be passive components.

[0076] In this embodiment, the semiconductor device 111 is an image sensor (imaging device). The image sensor is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The image sensor has a function of converting light incident through the lens unit 602 into an electric signal. In this embodiment, the semiconductor device 121 is a processor (arithmetic device) such as a digital signal processor or an image signal processor. The image signal processor has a function of acquiring an electric signal indicating image data from the semiconductor device 111, which is an image sensor (imaging device), correcting the acquired electric signal, and generating and outputting the corrected image data. An article in which the circuit board 101 connected to the wiring board 200 includes an image sensor in this way can be called an imaging module or an imaging unit. The imaging module is an example of an electronic module, and the imaging unit is an example of the electronic unit 100.

[0077] In this embodiment, electronic unit 100 includes driving device 160 that moves circuit board 101 (wiring board 110 and semiconductor device 111). Driving device 160 includes a motor, which is an example of a driving source. In digital camera 600 including electronic unit 100 including driving device 160, moving semiconductor device 111 via circuit board 101 can achieve a camera shake correction (anti-shake) function. The driving source in driving device 160 is not limited to an electromagnetic motor, but may be a piezoelectric motor such as an ultrasonic motor, or an electrostatic motor. Since wiring board 200 is connected to circuit board 101 that is moved in this way, wiring board 200 is required to be flexible.

[0078] It should be noted that instead of electronic unit 100 having wiring board 200, circuit board 101, and circuit board 102, an article having either circuit board 101 or circuit board 102, and further having driving device 160 and other components, can also be referred to as an electronic unit.

[0079] In this embodiment, wiring board 200 is mounted on digital camera 600 in a bent state, and is disposed so that shield layer 15 is on the outer side of the curved surface. That is, shield layer 15 corresponds to the surface on the housing 611 side.

[0080] The wireless communication unit 150 performs wireless communication in the GHz band and is modularized. The wireless communication unit 150 has a rigid wiring board, which is an example of the wiring board 151 including an antenna (not shown), and a wireless communication IC 152 mounted on the wiring board 151. The antenna is provided in the same plane as the wireless communication IC 152 and is disposed in a position close to the housing 611 so as to facilitate communication with the outside. The wireless communication IC 152 is preferably capable of transmitting and / or receiving image data by performing wireless communication with an external device, such as a PC or a wireless router, via the antenna. In this embodiment, the wireless communication IC 152 is capable of transmitting and receiving data via the antenna. Specifically, the wireless communication IC 152 modulates a digital signal indicating image data acquired from the semiconductor device 121 and transmits the modulated digital signal from the antenna as radio waves of a communication frequency of a wireless standard. The wireless communication IC 152 demodulates the radio waves received by the antenna into a digital signal indicating image data. The wireless communication IC 152 performs wireless communication with an external device in compliance with a standard such as Wi-Fi (registered trademark) or Bluetooth (registered trademark). If shield layer 15 provided on wiring board 200 in electronic unit 100 serving as an imaging unit is used as an electromagnetic shield, it is possible to prevent electromagnetic waves emitted from wireless communication unit 150 from generating noise in electronic unit 100. Note that wiring board 200 can also be used to connect wiring board 151 to another wiring board.

[0081] <Third embodiment> In order to bond a flexible wiring board and a rigid substrate in a small area, direct bonding by soldering is performed. Patent Document 2 discloses a flexible cable that facilitates direct bonding by using a mesh-structure shield. However, with only a mesh shield layer as in Patent Document 2, the terminal portion, which is the bonding portion, is deformed, making it difficult to align with the land or conductor pattern of the rigid substrate, which can cause bonding defects. The third embodiment provides a flexible wiring board that is less likely to cause bonding defects.

[0082] The third embodiment will be described with reference to Figures 15 and 16. The differences from the first embodiment will be mainly described, and the description of the configurations with the same reference numerals will be omitted as appropriate. In electronic unit 100 of the third embodiment, connector 112 is not mounted on wiring board 110 constituting circuit board 101. Also, connector 122 is not mounted on wiring board 120 constituting circuit board 102. Therefore, insulating portion 16 provided around connector 112 of wiring board 200 in the first embodiment is not provided.

[0083] Wiring board 110 constituting circuit board 101 has conductor pattern 18 electrically connected to semiconductor device 111. The material of conductor pattern 18 is not particularly limited, and may be, for example, a metal such as gold, copper, or silver, or a conductive oxide. Conductive pattern 18 is electrically connected to terminal portion 116 of wiring board 200 (described later) by a conductive bonding member (not shown). The conductive bonding member is, for example, solder or conductive resin.

[0084] Similar to wiring board 110, wiring board 120 constituting circuit board 102 has conductor pattern 28 electrically connected to semiconductor device 121. The material of conductor pattern 28 is not particularly limited, and may be, for example, a metal such as gold, copper, or silver, or a conductive oxide. Conductive pattern 28 is electrically connected to terminal portion 216 of wiring board 200 by a conductive bonding member (not shown). The conductive bonding member may be, for example, solder or conductive resin.

[0085] Wiring board 200 according to this embodiment will be described with reference to Figures 15 and 16. Figure 16(a) is a cross-sectional view of wiring board 200 taken along line AA in Figure 15, Figure 16(b) is a cross-sectional view of wiring board 200 taken along line BB in Figure 15, and Figure 16(c) is a cross-sectional view of wiring board 200 taken along line CC in Figure 15.

[0086] <Wiring board configuration> In the wiring board 200 of the third embodiment, a base material 12 which is an insulating substrate, a wiring layer 13 having a signal line 22, and a coverlay 14 which is made up of an adhesive layer 14a and a covering layer 14b which are insulating layers are laminated in this order. In the wiring board 200, in the X direction (first direction) in which the signal line extends, a terminal portion 116 which is a connection portion with a conductor pattern 18 of a circuit board 101, and a reinforcing layer 115 adjacent to the terminal portion 116 are arranged in this order. In the reinforcing layer 115, a first reinforcing portion 115a adjacent to the terminal portion 116 and a second reinforcing portion 115b adjacent to the first reinforcing portion 115a are arranged in this order. That is, the wiring board 200 of the third embodiment is different from the first embodiment in that it has a reinforcing layer 115 instead of a shield layer 15.

[0087] Reinforcing layer 115 has a function of suppressing undulations in the terminal portion of wiring board 200 and a function of protecting wiring board 200. In addition, by using a conductive material for reinforcing layer 115, it can also function as a shielding member. Specifically, it shields against EMI (Electromagnetic interference) caused by radiation noise generated by electromagnetic radiation from signal line 22.

[0088] Examples of materials constituting the reinforcing layer 15 include plastics such as epoxy resins, imide resins, phenol resins, and cyanate resins. In addition, the reinforcing layer 15 may contain a filler. Examples of the filler to be contained include silica, kaolin, talc, and alumina. These may be mixed. In addition to the filler, fibers such as glass cloth using glass fiber bundles, carbon fiber bundles, polyester fiber bundles, nylon fiber bundles, and aramid fiber bundles may be used. Alternatively, examples of materials constituting the reinforcing layer 15 include metals such as copper, aluminum, nickel, iron, gold, silver, platinum, tungsten, chromium, titanium, tin, lead, and palladium. One or more of these metals may be combined. Among these, silver is preferable from the viewpoints of conductivity, Young's modulus, and low cost.

[0089] The thickness of the reinforcing layer 15 is preferably 1 μm or more, and more preferably 5 μm or more. If the thickness is less than 1 μm, sufficient bending resistance may not be obtained. When the reinforcing layer 15 is used as a shielding member, the surface resistance value of the reinforcing layer 15 is preferably 1 Ω / □ or less, and more preferably 0.1 Ω / □ or less.

[0090] 16(a) is a cross-sectional view of terminal portion 116 of wiring board 200. In terminal portion 116, wiring layer 13 having signal line 22 is provided on substrate 12, and coverlay 14 and reinforcing layer 15 are not laminated on signal line 22. That is, in terminal portion 116, the end of signal line 22 is exposed.

[0091] FIG. 16(b) is a cross-sectional view of a portion of wiring board 200 where first reinforcing portion 115a is provided. In this region, wiring board 200 is laminated in order of base material 12, which is an insulating substrate, wiring layer 13 having signal line 22, coverlay 14 consisting of adhesive layer 14a and covering layer 14b, which are insulating layers, and first reinforcing portion 115a. First reinforcing portion 115a has higher rigidity than second reinforcing portion 115b. The rigidity is determined by the Young's modulus, thickness, width, length, aperture ratio, etc. of the material used. First reinforcing portion 115a is provided in a region from the end of the insulating layer to 5 times the length of the terminal portion in the X direction. First reinforcing portion 115a is provided continuously in the Y direction intersecting with the X direction so as to cover signal line 22 and ground line 133.

[0092] 16(c) is a cross-sectional view of a portion of wiring board 200 where second reinforcing portion 115b is provided. In this region, wiring board 200 has base material 12 which is an insulating substrate, wiring layer 13 having signal line 22, coverlay 14 which is made up of adhesive layer 14a and coating layer 14b which are insulating layers, and second reinforcing portion 115b laminated in this order. Second reinforcing portion 115b has a lower rigidity than first reinforcing portion 115a. Second reinforcing portion 115b is provided in a region which is longer than five times the X-directional length of the terminal portion from the end of the insulating layer in the X-direction.

[0093] Wiring board 200 of the third embodiment includes first reinforcing portion 115a having higher rigidity than second reinforcing portion 115b in a region from an end of insulating layer to 5 times the length of terminal portion in the X direction. That is, reinforcing layer 115 having higher rigidity is disposed only in the vicinity of terminal portion 116. Therefore, deformation such as undulation is unlikely to occur in terminal portion 116 when terminal portion 116 is bonded to conductor pattern 18. Therefore, it is possible to provide a flexible wiring board in which bonding failure is less likely to occur than in the embodiment disclosed in Patent Document 2. In addition, first reinforcing portion 115a is continuously provided so as to cover signal line 22 and ground line 133 in the Y direction, so that it is possible to suppress undulation of terminal portion 116 caused by deformation due to shrinkage of adhesive layer 14a between signal lines 22 during hardening and deformation due to a difference in rigidity between the region where signal line 22 and ground line 133 are arranged and the region where they are not arranged.

[0094] It is preferable that the length of the first reinforcing portion 115a in the X direction is 0.5 or more times the length of the terminal portion in the X direction. This is to better suppress undulation of the terminal portion .

[0095] The first reinforcing portion 115a may have an opening. The shape of the opening may be a rhombus, an ellipse, a rectangle, a hexagon, or the like, and is not particularly limited. In addition, a shape in which a plurality of shapes are selected and arranged from among these shapes may be used. However, the opening ratio, which indicates the area ratio of the openings in a predetermined plane, is preferably smaller than that of the second reinforcing portion 115b. This is because, when the first reinforcing portion 115a and the second reinforcing portion 115b are made of the same material, the rigidity of the first reinforcing portion 115a is more easily increased than that of the second reinforcing portion 115b. The first reinforcing portion 115a is preferably a solid color without an opening. In addition, the manufacturing process can be simplified by using the same material for the first reinforcing portion 115a and the second reinforcing portion 115b.

[0096] It is preferable that the thickness of the first reinforcing portion 115a is greater than the thickness of the second reinforcing portion 115b. This is because, when the same material is used for the first reinforcing portion 115a and the second reinforcing portion 115b, it is easier to increase the rigidity of the first reinforcing portion 115a than that of the second reinforcing portion 115b.

[0097] It is preferable that the first reinforcing portion 115a is provided with a gap between it and the terminal portion 116. When the first reinforcing portion 115a is provided with a gap between it and the terminal portion 116, the insulating layer, which is the coating layer 14b of the coverlay 14, is exposed. This is because, when a conductive material is used for the first reinforcing portion 115a, it is possible to prevent a short circuit between the terminal portion 116 and the first reinforcing portion 115a. Specifically, it is preferable that the insulating layer is exposed for 4 mm or less in the X direction. This is because if it exceeds 4 mm, the effect of suppressing undulation of the terminal portion 116 may be insufficient.

[0098] The opening ratio of the second reinforcing portion 115b is preferably 50% or more. The thickness of the second reinforcing portion 115b is preferably 10 μm or less. In either case, this is to make the rigidity of the second reinforcing portion 115b smaller than the rigidity of the first reinforcing portion 115a.

[0099] It is preferable that the second reinforcing portion 115b is connected to the first reinforcing portion 115a. In other words, it is preferable that the first reinforcing portion 115a and the second reinforcing portion 115b are formed continuously. This is because the manufacturing process can be simplified.

[0100] Each signal line 22 is a wiring having a band capable of transmitting the digital data signal to be handled. With an increase in the amount of signal transmission, it is preferable to configure differential signal wiring in which a pair of signal lines 22 is one set among the multiple signal lines 22. When the signal lines 22 are configured as differential signal wiring, it is preferable that the distance between adjacent signal lines 22 is greater than the distance between the signal lines 22 and the reinforcement layer 15. By making the distance between adjacent signal lines 22 greater than the distance between the signal lines 22 and the reinforcement layer 15, the electromagnetic field created by the signal can be more biased in the direction of the reinforcement layer 15, and good transmission characteristics can be obtained. The multiple signal lines 22 may include wiring that transmits single-ended signals such as control signals and response signals. The wiring layer 13 may also have a ground line 133 in addition to the signal lines 22.

[0101] <Example> The present invention will now be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. The evaluation method (measurement method) of the wiring board in the present invention is as follows.

[0102] The evaluation methods for the wiring boards according to the examples and comparative examples will be described below.

[0103] (Terminal warpage measurement) The warpage of the terminal portion of the wiring board was evaluated using a one-shot shape measuring instrument (VR-3200 manufactured by Keyence Corporation). First, wiring board 200 is placed on a flat measuring table, and the height of terminal portion 116 is measured by shining light on terminal portion 116. Next, from the obtained measurement data, an analysis application (VR-3000 G2 manufactured by Keyence Corporation) is used to measure the PV value from a pseudo-plane connecting the end points of terminal portion 116. The evaluation criteria were as follows: A (Excellent): PV value less than 50 μm B (Good): PV value 50μm or more and less than 75μm C (Acceptable): PV value 75μm or more and less than 100μm D (unacceptable): PV value 100μm or more

[0104] Example 7 The wiring board 200 shown in FIG. 17(a) was fabricated. A polyimide film (Kapton 100H manufactured by DuPont-Toray Co., Ltd.) having a thickness of 25 μm was prepared as the base material 12 (insulating substrate). A copper foil having a thickness of 12 μm was laminated on the base material 12 as the wiring layer 13, and a signal line 22 and a ground line 133 having a total length of 100 mm were formed by etching. The signal lines 22 were formed as a pair of differential signal lines with a spacing between the signal lines 22 of 55 μm and a width of 205 μm for each pair of signal lines 22. Meanwhile, the ground lines 133 were arranged on both sides of the pair of signal lines 22 with a width of 100 μm and a spacing of 150 μm between the adjacent signal lines 22, thereby obtaining the wiring layer 13. From the viewpoint of the insulation of the signal lines 22, the base material 12 was prepared so that the ground lines 133 located at both ends of the wiring board 200 were located 500 μm inward from the outside of the wiring board 200.

[0105] Next, the coverlay 14 is formed on the wiring layer 13. An adhesive with a thickness of 25 μm was used as the adhesive layer 14a, and a coverlay with a thickness of 15 μm (CEAM0525KA manufactured by Arisawa Manufacturing Co., Ltd.) with a total thickness of 37.5 μm was used as the covering layer 14b. At this time, the signal line 22 was exposed 1.5 mm from the end of the wiring board 200 to provide a terminal portion. Next, the reinforcing layer 15 was formed on the coverlay 14. The reinforcing layer 15 was formed by printing a silver paste (product name: DD-1630L-245) manufactured by Kyoto Elex Co., Ltd. with a screen printer (MT-320T manufactured by Micro-Tech Co., Ltd.). At this time, the reinforcing layer 15 was formed so that the opening pattern of the screen printing plate was adjusted to print two patterns, a first reinforcing portion 115a and a second reinforcing portion 115b, which have different opening shapes. First reinforcing portion 115a was formed in a solid pattern with a thickness of 20 μm from a position 1 mm to a position 7.5 mm from the end of terminal portion 116 on the coverlay 14 side in the X direction so as to cross all of signal line 22 and ground line 133. Second reinforcing portion 115b was formed continuous with first reinforcing portion 115a, in a diamond mesh pattern with a thickness of 5 μm, a line width of 58 μm, and openings of 2000 μm in the X direction and 500 μm in the Y direction, with the longitudinal direction of the openings parallel to signal line 22. From the above configuration, wiring board 200 of Example 7 was obtained.

[0106] Example 8 As shown in FIG. 17(b), the first reinforcing portion 115a of the reinforcing layer 15 was formed from a position of 1 mm to a position of 1.75 mm in the X direction from the end of the terminal portion 116 on the coverlay 14 side, and the rest was formed in the same manner as in Example 7, thereby obtaining the wiring board 200 of Example 8.

[0107] Example 9 As shown in FIG. 17(c), the first reinforcing portion 115a of the reinforcing layer 15 was formed from a position of 1 mm to a position of 1.45 mm in the X direction from the end of the terminal portion 116 on the coverlay 14 side, and the rest was formed in the same manner as in Example 7, thereby obtaining the wiring board 200 of Example 9.

[0108] Example 10 As shown in FIG. 17(d), the first reinforcing portion 115a of the reinforcing layer 15 was formed from a position of 4 mm to a position of 7.5 mm in the X direction from the end of the terminal portion 116 on the coverlay 14 side, and the rest was formed in the same manner as in Example 7, thereby obtaining the wiring board 200 of Example 10.

[0109] Example 11 As shown in FIG. 17(e), the first reinforcing portion 115a of the reinforcing layer 15 was formed from a position of 5 mm to a position of 7.5 mm in the X direction from the end of the terminal portion 116 on the coverlay 14 side, and the rest was formed in the same manner as in Example 7, thereby obtaining the wiring board 200 of Example 11.

[0110] Example 12 As shown in FIG. 17( f), first reinforcing portion 115a of reinforcing layer 15 was formed in a diamond mesh pattern having a thickness of 12 μm and a line width of 125 μm extending from a position 1 mm to a position 7.5 mm from the end of terminal portion 116 on the coverlay 14 side in the X direction, with openings of 2000 μm in the X direction and 500 μm in the Y direction, with the longitudinal direction of the openings being parallel to signal line 22. The rest of the pattern was formed in the same manner as in Example 7, thereby obtaining wiring board 200 of Example 12.

[0111] Comparative Example 4 As shown in FIG. 18(a), the first reinforcing portion 115aX of the reinforcing layer 15X was formed from a position of 1 mm to a position of 8 mm in the X direction from the end of the terminal portion 116X on the coverlay 14 side, and the rest was formed in the same manner as in Example 7, thereby obtaining a wiring board 200X of Comparative Example 4.

[0112] Comparative Example 5 18(b), the first reinforcing portion 115aX of the reinforcing layer 15X was formed in a diamond-shaped mesh pattern having a thickness of 5 μm, a line width of 58 μm, and an opening of 2000 μm in the X direction and 500 μm in the Y direction from the end of the terminal portion 116X on the coverlay 14 side from a position 1 mm to a position 7.5 mm in the X direction, with the opening being formed so that the longitudinal direction (X direction) of the opening is parallel to the signal line 22, and the second reinforcing portion 115bX was formed in a solid pattern having a thickness of 20 μm adjacent to the first reinforcing portion 115aX. The remaining parts were formed in the same manner as in Example 7, to obtain a wiring board 200 of Comparative Example 5.

[0113] Comparative Example 6 As shown in FIG. 18(c), the first reinforcing portion 115aX of the reinforcing layer 115X was formed in a solid pattern that did not continuously cross all of the signal lines 22 and the ground lines 133, and the rest was formed in the same manner as in Example 7, thereby obtaining the wiring board 200 of Comparative Example 6.

[0114] [Table 2]

[0115] As shown in Table 2, the undulation of the terminal portion 116 was suppressed in all of the wiring boards 200 of Examples 7 to 12. Comparing Example 7 and Example 8, Example 7 had a smaller amount of warping. This is because Example 7 has a larger area occupied by the first reinforcing portion 115a in the region from the end of the terminal portion 116 on the coverlay 14 side to 5 times the length of the terminal portion 116 in the X direction, and has a higher rigidity, so that it was possible to more effectively block the undulation caused by the shrinkage of the adhesive layer of the wiring portion. Comparing Example 7 and Example 10, Example 7 had a smaller amount of warping. This is because Example 7 has the first reinforcing portion 115a in a region closer to the terminal portion 116, so that it was possible to more effectively reinforce the terminal portion 116, and in addition, Example 4 was able to suppress the shrinkage of the adhesive layer that occurred in the region not having the reinforcing layer 15. In Comparative Example 4, the distance from the end of the terminal portion 116X on the coverlay 14 side to the end of the first reinforcing portion 115a was longer than 5 times the length of the terminal portion 116X. With such a configuration, the contraction of the reinforcing layer 115 itself causes undulation in the terminal portion 116X. In Comparative Example 5, the first reinforcing portion 115aX has a smaller rigidity than the second reinforcing portion 115bX. With such a configuration, the rigidity is insufficient to suppress undulation transmitted from the wiring portion near the terminal portion 116X, and the reinforcing layer 115X itself contracts significantly because a region with high rigidity is provided over a large area as in Comparative Example 4. In Comparative Example 6, the first reinforcing portion 115a does not continuously cross all the signal lines 22 and the ground line 133. With such a configuration, undulation according to the arrangement of the signal lines occurs due to the contraction of the adhesive between the signal lines and the difference in rigidity between the region where the signal lines are arranged and the region where the signal lines are not arranged. In addition, the constraint of the adhesive between the signal lines is weakened, and the effect of contraction also becomes greater.

[0116] The above-described embodiment can be modified as appropriate without departing from the technical concept.

[0117] For example, a plurality of embodiments can be combined. One end of a flexible wiring board can have the configuration of the first embodiment, and the other end can have the configuration of the third embodiment. Furthermore, the flexible wiring board of the third embodiment can be used in the second embodiment. Furthermore, some of the features of at least one of the embodiments can be deleted or replaced.

[0118] In addition, new matters may be added to at least one embodiment. The disclosure of this specification includes not only what is explicitly described in this specification, but also all matters that can be understood from this specification and the drawings attached to this specification.

[0119] Furthermore, the disclosure of this specification includes the complement of each concept described in this specification. In other words, if this specification contains a statement that "A is greater than B," for example, even if the statement that "A is not greater than B" is omitted, this specification can be said to disclose that "A is not greater than B." This is because when a statement that "A is greater than B" is made, it is assumed that the case in which "A is not greater than B" is taken into consideration.

[0120] The disclosure of the present invention is given below.

[0121] (Section 1) 1. A flexible wiring board comprising a signal line, a shielding layer provided to overlap the signal line in a planar view, and an insulating portion on the side of the signal line opposite the side on which the shielding layer is provided, wherein the shielding layer has an opening, the shielding layer has a first region having an opening ratio equal to or greater than a predetermined value, and a second region having an opening ratio lower than that of the first region, the second region is positioned at a position overlapping the insulating portion and the signal line in a planar view, and the boundary between the first region and the second region is spaced apart from the insulating portion in a planar view.

[0122] (Section 2) 2. The flexible wiring board according to item 1, wherein the insulating portion is a reinforcing plate having a thickness greater than that of the shielding layer.

[0123] (Section 3) 1. A flexible wiring board comprising a signal line, a shielding layer provided so as to overlap the signal line in a planar view, and a reinforcing plate on the side of the signal line opposite the side on which the shielding layer is provided, wherein the shielding layer has an opening, and the shielding layer has a first region having an opening rate equal to or greater than a predetermined value and a second region having an opening rate lower than that of the first region, and the second region is positioned at a position overlapping the reinforcing plate and the signal line in a planar view.

[0124] (Section 4) 4. The flexible wiring board according to any one of items 1 to 3, wherein the shielding layer in the first region has a mesh shape.

[0125] (Section 5) 5. The flexible wiring board according to any one of items 1 to 4, wherein the shielding layer in the second region has a mesh shape.

[0126] (Section 6) 6. The flexible wiring board according to item 5, wherein the line width of the shielding layer in the first region is smaller than that of the shielding layer in the second region.

[0127] (Section 7) 7. The flexible wiring board according to any one of items 1 to 6, wherein the shielding layer in the second region does not have the opening.

[0128] (Section 8) 8. The flexible wiring board according to any one of items 1 to 7, wherein the shielding layer in the second region is not provided with the opening.

[0129] (Section 9) 9. The flexible wiring board according to any one of items 1 to 8, wherein the opening ratio of the first region is 60% or more.

[0130] (Section 10) 10. The flexible wiring board according to any one of items 1 to 9, wherein the aperture ratio of the second region is 50% or less.

[0131] (Section 11) 11. The flexible wiring board according to any one of claims 1 to 10, characterized in that the boundary between the first region and the second region is located on the insulating portion side of the end face of the first region that intersects with the signal line and is opposite to the second region.

[0132] (Section 12) Item 12. The flexible wiring board according to item 11, wherein the boundary between the first region and the second region is located at a position that is 10% or less of the distance from the insulating portion to the end face.

[0133] (Section 13) 11. The flexible wiring board according to any one of claims 1 to 10, characterized in that the shielding layer further has a third region having an aperture ratio lower than that of the first region, and the first region is provided between the second region and the third region.

[0134] (Section 14) Item 14. The flexible wiring board described in item 13, characterized in that the boundary between the first region and the second region is located on the insulating portion side of the boundary between the first region and the third region.

[0135] (Section 15) 15. The flexible wiring board according to any one of items 1, 2, or 4 to 14, wherein the hardness of the insulating portion is higher than the hardness of the shielding layer.

[0136] (Section 16) Item 16. The flexible wiring board according to any one of items 1, 2, or 4 to 15, wherein an insulating member is provided between the insulating portion and the signal line.

[0137] (Section 17) Item 17. The flexible wiring board according to item 16, wherein the insulating portion is thicker than the insulating member.

[0138] (Section 18) Item 18. The flexible wiring board according to any one of items 1 to 17, characterized in that the signal line is a differential signal wiring consisting of a first signal line and a second signal line adjacent to the first signal line, and the distance between the first signal line and the second signal line is greater than the distance between the first signal line and the shielding layer.

[0139] (Section 19) A flexible wiring board in which a signal line, an insulating layer, and a reinforcing layer are laminated in this order, The reinforcing layer has a second reinforcing portion and a first reinforcing portion having a higher rigidity than the second reinforcing portion, In a first direction in which the signal line extends, an end portion of the signal line is a terminal portion to which the signal line is exposed, the first reinforcing portion is adjacent to the terminal portion and is provided on the insulating layer provided on the signal line, the second reinforcement portion is adjacent to the first reinforcement portion and is provided on the insulating layer provided on the signal line, the first reinforcing portion is provided in a region from an end of the insulating layer to a length five times the length of the terminal portion in the first direction, the second reinforcing portion is provided in a region from an end of the insulating layer that is longer than five times the length of the terminal portion in the first direction, The flexible wiring board, wherein the first reinforcing portion is continuously provided in a direction intersecting the first direction.

[0140] (Section 20) 20. The flexible wiring board according to item 19, wherein the length of the first reinforcing portion in the first direction is 0.5 times or more the length of the terminal portion in the first direction.

[0141] (Section 21) 21. The flexible wiring board according to item 19 or 20, characterized in that the terminal portion and the first reinforcing portion are provided with a gap therebetween, and the insulating layer is exposed between the terminal portion and the first reinforcing portion.

[0142] (Section 22) 22. The flexible wiring board according to item 21, wherein the insulating layer is exposed by 4 mm or less in the first direction.

[0143] (Section 23) 23. The flexible wiring board according to any one of items 19 to 22, wherein the first reinforcing portion and the second reinforcing portion contain silver.

[0144] (Section 24) 24. The flexible wiring board according to any one of items 19 to 23, wherein an aperture ratio of the first reinforcing portion is smaller than an aperture ratio of the second reinforcing portion.

[0145] (Section 25) 25. The flexible wiring board according to any one of items 19 to 24, wherein the first reinforcing portion has a thickness greater than a thickness of the second reinforcing portion.

[0146] (Section 26) 26. The flexible wiring board according to any one of items 19 to 25, wherein the first reinforcing portion and the second reinforcing portion are connected to each other.

[0147] (Section 27) Item 19. A method for manufacturing a wiring board according to any one of items 1 to 18, wherein the shielding layer is formed by screen printing.

[0148] (Section 28) A wiring board according to any one of items 1 to 18, a rigid wiring board to which an end of the wiring board is connected; and an electronic component mounted on the rigid wiring board.

[0149] (Section 29) 29. The electronic module described in item 28, wherein the electronic components include an image sensor.

[0150] (Section 30) Item 28 or 29, an electronic module according to item 28 or 29; and a drive device that moves the rigid wiring board.

[0151] (Section 31) An electronic module according to any one of claims 28 to 30, a circuit board to which an end portion of the wiring board other than the end portion is connected, An electronic device, characterized in that a processor for processing signals output from the electronic components is mounted on the circuit board.

[0152] (Section 32) An electronic module according to any one of claims 28 to 30, a housing that houses the electronic module; the wiring board is accommodated in the housing in a bent state, The electronic device according to claim 1, wherein the shielding layer is provided on an outer surface of the curved surface of the wiring board.

[0153] (Section 33) 27. A method for manufacturing a wiring board according to any one of claims 19 to 26, wherein the shielding layer is formed by screen printing.

[0154] (Section 34) Item 27. The wiring board according to any one of items 19 to 26, a rigid wiring board to which an end of the wiring board is connected; and an electronic component mounted on the rigid wiring board.

[0155] (Section 35) 35. The electronic module described in item 34, wherein the electronic components include an image sensor.

[0156] (Section 36) Item 34 or 35, an electronic module according to item 34 or 35; and a drive device that moves the rigid wiring board.

[0157] (Section 37) An electronic module according to any one of claims 34 to 36, a circuit board to which an end portion of the wiring board other than the end portion is connected, An electronic device, characterized in that a processor for processing signals output from the electronic components is mounted on the circuit board.

[0158] (Section 38) An electronic module according to any one of claims 34 to 36, a housing that houses the electronic module; the wiring board is accommodated in the housing in a bent state, The electronic device according to claim 1, wherein the shielding layer is provided on an outer surface of the curved surface of the wiring board. [Explanation of symbols]

[0159] 15 Shielding layer 16 Insulation section 17 Opening 22 Signal Line 200 Flexible wiring board

Claims

1. A flexible wiring board including a signal line, a shielding layer provided so as to overlap the signal line in a planar view, and an insulating portion on an opposite side of the signal line to the side on which the shielding layer is provided, The shield layer is provided with an opening, the shield layer has a first region having an aperture ratio equal to or greater than a predetermined value and a second region having an aperture ratio lower than that of the first region, the second region is disposed at a position overlapping the insulating portion and the signal line in a plan view, A flexible wiring board, characterized in that the boundary between the first region and the second region is disposed at a distance from the insulating portion in a plan view.

2. 2. The flexible wiring board according to claim 1, wherein the insulating portion is a reinforcing plate having a thickness greater than that of the shielding layer.

3. A flexible wiring board including a signal line, a shielding layer provided so as to overlap the signal line in a planar view, and a reinforcing plate on an opposite side of the signal line to the side on which the shielding layer is provided, The shield layer is provided with an opening, the shield layer has a first region having an aperture ratio equal to or greater than a predetermined value and a second region having an aperture ratio lower than that of the first region, The flexible wiring board, characterized in that the second region is disposed at a position overlapping the reinforcing plate and the signal line in a plan view.

4. The flexible wiring board according to claim 1 , wherein the shielding layer in the first region has a mesh shape.

5. The flexible wiring board according to claim 1 , wherein the shielding layer in the second region has a mesh shape.

6. 6. The flexible wiring board according to claim 5, wherein the line width of the shielding layer in the first region is smaller than that of the shielding layer in the second region.

7. 7. The flexible wiring board according to claim 6, wherein the line width of the shielding layer in the second region is 1.5 times or more the line width of the shielding layer in the first region.

8. The flexible wiring board according to claim 1 , wherein the shielding layer in the second region is not provided with the opening.

9. 2. The flexible wiring board according to claim 1, wherein the opening ratio of the first region is 60% or more.

10. 2. The flexible wiring board according to claim 1, wherein the aperture ratio of the second region is 50% or less.

11. The flexible wiring board according to claim 1, characterized in that the boundary between the first region and the second region is located on the insulating portion side of the end face of the first region that intersects the signal line and is opposite to the second region.

12. 12. The flexible wiring board according to claim 11, wherein the boundary between the first region and the second region is provided at a position that is 10% or less of the distance from the insulating portion to the end surface.

13. 2. The flexible wiring board according to claim 1, wherein the shielding layer further includes a third region having an aperture ratio lower than that of the first region, and the first region is provided between the second region and the third region.

14. 14. The flexible wiring board according to claim 13, wherein the boundary between the first region and the second region is provided closer to the insulating portion than the boundary between the first region and the third region.

15. 2. The flexible wiring board according to claim 1, wherein the insulating portion has a hardness higher than a hardness of the shielding layer.

16. 2. The flexible wiring board according to claim 1, further comprising an insulating member provided between the insulating portion and the signal line.

17. 17. The flexible wiring board according to claim 16, wherein the insulating portion is thicker than the insulating member.

18. 2. The flexible wiring board according to claim 1, characterized in that the signal line is a differential signal wiring consisting of a first signal line and a second signal line adjacent to the first signal line, and the distance between the first signal line and the second signal line is greater than the distance between the first signal line and the shielding layer.

19. A flexible wiring board in which a signal line, an insulating layer, and a reinforcing layer are laminated in this order, The reinforcing layer has a second reinforcing portion and a first reinforcing portion having a higher rigidity than the second reinforcing portion, In a first direction in which the signal line extends, an end portion of the signal line is a terminal portion to which the signal line is exposed, the first reinforcing portion is adjacent to the terminal portion and is provided on the insulating layer provided on the signal line, the second reinforcing portion is adjacent to the first reinforcing portion and is provided on the insulating layer provided on the signal line, the first reinforcing portion is provided in a region from an end of the insulating layer to a length five times the length of the terminal portion in the first direction, the second reinforcing portion is provided in a region from an end of the insulating layer that is longer than five times the length of the terminal portion in the first direction, The flexible wiring board, wherein the first reinforcing portion is continuously provided in a direction intersecting the first direction.

20. 20. The flexible wiring board according to claim 19, wherein the length of the first reinforcing portion in the first direction is 0.5 times or more the length of the terminal portion in the first direction.

21. 20. The flexible wiring board according to claim 19, wherein the terminal portion and the first reinforcing portion are provided with a gap therebetween, and the insulating layer is exposed between the terminal portion and the first reinforcing portion.

22. 22. The flexible wiring board according to claim 21, wherein the insulating layer is exposed by 4 mm or less in the first direction.

23. The flexible wiring board according to claim 19 , wherein the first reinforcing portion and the second reinforcing portion contain silver.

24. The flexible wiring board according to claim 19 , wherein an aperture ratio of the first reinforcing portion is smaller than an aperture ratio of the second reinforcing portion.

25. The flexible wiring board according to claim 19 , wherein the first reinforcing portion has a thickness greater than a thickness of the second reinforcing portion.

26. The flexible wiring board according to claim 19 , wherein the first reinforcing portion and the second reinforcing portion are connected to each other.

27. 19. The method for manufacturing a wiring board according to claim 1, wherein the shielding layer is formed by screen printing.

28. A wiring board according to any one of claims 1 to 18; a rigid wiring board to which an end of the wiring board is connected; and an electronic component mounted on the rigid wiring board.

29. 30. The electronic module of claim 28, wherein the electronic component comprises an image sensor.

30. 29. An electronic module according to claim 28; and a drive device that moves the rigid wiring board.

31. 29. An electronic module according to claim 28; a circuit board to which an end portion of the wiring board other than the end portion is connected, An electronic device, characterized in that a processor for processing signals output from the electronic components is mounted on the circuit board.

32. 29. An electronic module according to claim 28; a housing that houses the electronic module; the wiring board is accommodated in the housing in a bent state, The electronic device according to claim 1, wherein the shielding layer is provided on an outer surface of the curved surface of the wiring board.

33. 27. The method for manufacturing a wiring board according to claim 19, wherein the shielding layer is formed by screen printing.

34. A wiring board according to any one of claims 19 to 26, a rigid wiring board to which an end of the wiring board is connected; and an electronic component mounted on the rigid wiring board.

35. 35. The electronic module of claim 34, wherein the electronic component comprises an image sensor.

36. An electronic module according to claim 34; and a drive device that moves the rigid wiring board.

37. An electronic module according to claim 34; a circuit board to which an end portion of the wiring board other than the end portion is connected, An electronic device, characterized in that a processor for processing signals output from the electronic components is mounted on the circuit board.

38. An electronic module according to claim 34; a housing that houses the electronic module; the wiring board is accommodated in the housing in a bent state, The electronic device according to claim 1, wherein the shielding layer is provided on an outer surface of the curved surface of the wiring board.

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