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

Abstract

To provide a flexible wiring board achieving both flexibility and durability, a manufacturing method, an electronic module, an electronic unit, and an electronic apparatus.SOLUTION: In an electronic unit, a flexible wiring board 200 includes a substrate 12, a signal line formed on one side of the substrate 12, a shield layer 15 overlapping the signal line in plan view, and a protective layer 18 covering the shield layer 15, the flexible wiring board having an insulation part 16 on the other side of the substrate 12. The protective layer 18 has a first portion 201 having a film thickness t1 that is a film thickness from an upper surface 15a of the shield layer 15 to the outermost surface of the protective layer 18, and a second portion 202 having a film thickness t2 that is a film thickness from the upper surface 15a of the shield layer 15 to the outermost surface of the protective layer 18, the film thickness t2 being greater than the film thickness t1. The protective layer 18 overlaps at least part of an end of the insulation part 16 in plan view, in the second portion 202.SELECTED DRAWING: Figure 4

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, but with the increasing demand for even higher performance and smaller size, flexible wiring boards (Flexible Circuits), which are flexible and bendable and have signal wiring circuits formed on a flexible insulating film, are beginning to be used for the wiring boards. Such flexible wiring boards need to be durable against bending and warping at connection terminals for connecting to electronic devices and at parts where electronic components are attached.

[0003] In view of this, Patent Document 1 discloses an electro-optical display device in which a reinforcing plate is provided so as to cover the connection portions between the electrodes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-200728 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, merely providing a reinforcing plate as in Patent Document 1 was not enough to sufficiently prevent damage to the flexible wiring board.

[0006] The present invention has been made in view of the above problems, and has an object to achieve both flexibility and durability of a flexible wiring board. [Means for solving the problem]

[0007] The means for solving the above problem is a flexible wiring board having a substrate, a signal line formed on one surface of the substrate, a shielding layer overlapping the signal line in a planar view, a protective layer covering the shielding layer, and an insulating portion on the other surface of the substrate, wherein the protective layer has a first portion having a thickness t1 from a top surface of the shielding layer to an outermost surface of the protective layer, and a second portion having a thickness t2 from the top surface of the shielding layer to the outermost surface of the protective layer that is larger than the thickness t1, and the protective layer overlaps at least a portion of an end of the insulating portion in a planar view in the second portion. Effect of the Invention

[0008] According to the present invention, it is possible to provide a flexible wiring board that achieves both flexibility and durability of the flexible wiring board. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a top view of an electronic unit equipped with a flexible wiring board. [Diagram 2] FIG. 2 is a top view of an electronic unit equipped with a flexible wiring board. [Diagram 3] 2 is a cross-sectional view taken along line AA' in FIG. [Figure 4] FIG. 3 is a cross-sectional view taken along line BB' in FIG. [Diagram 5] FIG. 1 is a schematic diagram of a system used to evaluate the transmission characteristics of flexible wiring boards of examples and comparative examples. [Figure 6] 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 7] FIG. 13 is a top view of a wiring board according to a seventh embodiment. [Figure 8] FIG. 13 is a top view of a wiring board according to an eighth embodiment. [Figure 9] FIG. 13 is a top view of a wiring board according to a ninth embodiment. [Figure 10] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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.

[0011] First Embodiment Wiring board 200 according to the first embodiment will be described with reference to Figures 1, 2, 3, and 4. Figure 1 is a top view of electronic unit 100 including wiring board 200, and Figure 2 shows shield layer 15 and protective layer 18 in Figure 1, without showing signal line 22 and ground line 133.

[0012] 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 unit 100 can be configured by preparing an electronic module 10 in which the wiring board 200 is connected to the circuit board 101, and further connecting the wiring board 200 of the electronic module 10 to the circuit board 102. Also, an electronic device including the electronic unit 100 can be configured.

[0013] As shown in Fig. 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 on one surface, and each signal line 22 and each ground line 133 extends in the X direction. The plurality of signal lines 22 and the plurality of 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] Next, a cross section of wiring board 200 will be described with reference to Figures 3 and 4. Figure 3 is a cross section taken along line AA' in Figure 1. Figure 4 is a cross section taken along line BB' in Figure 2.

[0022] The wiring board 200 has a base material (insulating substrate) 12 over the entire region in the X direction, a coverlay 14 consisting of an adhesive layer 14a and a covering layer 14b, a wiring layer 13, a shielding layer 15, and a protective layer 18 covering the shielding layer. The wiring layer 13 has the above-mentioned multiple signal lines 22 and ground lines 133. In addition, a partial region of the wiring board 200 has an insulating portion 16 under the base material. The base material 12, the coverlay 14, the insulating portion 16, and the protective layer 18 are made of a material having electrical insulation. The wiring layer 13 and the shielding layer 15 are made of a material having electrical conductivity. The base material 12, the coverlay 14, the wiring layer 13, and the shielding layer 15 are formed by extending in the X direction. The signal lines 22 and the ground lines 133 constituting the wiring layer 13 are arranged at intervals in the Y direction inside the coverlay 14, but do not necessarily have to be arranged inside the coverlay 14.

[0023] 4, wiring board 200 of the present embodiment has a portion on the back surface (the other surface) of base material 12 where insulating portion 16 is provided, and a portion where insulating portion 16 is not provided. If insulating portion 16 is provided on the entire surface, there is a risk of impairing the flexibility of wiring board 200, so insulating portion 16 is provided only on a portion of the back surface of base material 12.

[0024] However, when wiring board 200 is bent, a larger force is applied to a portion of protective layer 18 that overlaps end 19 of insulating portion 16 in a planar view and a portion of shielding layer 15 that overlaps end 19 of insulating portion 16 in a planar view, compared to a portion that does not overlap end 19. This may cause cracks in shielding layer 15, which may deteriorate the signal transmission characteristics. Therefore, wiring board 200 of the present embodiment has a thickness t2 of protective layer 18 (second portion 202) that overlaps end 19 in a planar view that is larger than a thickness t1 of protective layer 18 (first portion 201) that does not overlap end 19. This provides a configuration that better protects the portion of shielding layer 15 to which a large force is applied, and can suppress cracks in shielding layer 15 even when wiring board 200 is bent.

[0025] Film thickness t1 and film thickness t2 are the distances from upper surface 15a of shielding layer 15 to the upper surface of protective layer 18. By providing first portion 201 in protective layer 18, wiring board 200 is not thick all over, and it is possible to provide wiring board 200 with excellent flexibility. On the other hand, by providing second portion 202 in protective layer 18, it is possible to provide wiring board 200 that suppresses the occurrence of cracks.

[0026] The thickness t2 is preferably 3 times or less than the thickness t1, and more preferably 2.5 times or less. The difference between the thickness t2 and the thickness t1 is preferably 0.5 μm or more and 20 μm or less. The thickness t1 is preferably 1 μm or more and 60 μm or less, and the thickness t2 is preferably 2 μm or more and 80 μm or less. Within the above ranges, flexibility and signal transmission characteristics can be achieved at the same time.

[0027] Insulating portion 16 is preferably provided across the entire width of wiring board 200 (the entire Y direction), but may be provided across only a portion of the width. By providing insulating portion 16 across the entire width of wiring board 200, stress on the side surface of insulating portion 16 is less likely to be applied to shielding layer 15, and the stress can be concentrated at end portion 19. In either case, however, it is sufficient that the thickness of protective layer 18 that overlaps the portion where end portion 19 of insulating portion 16 is provided in a plan view is film thickness t2.

[0028] End 19 is preferably provided at a position within 30% of the total length of wiring board 200 in the Y direction from the end of wiring board 200, and more preferably 15% or less. By providing end 19 closer to the end of wiring board 200, it can be arranged in a portion where wiring board 200 is easily bent.

[0029] Second portion 202 may be provided not only at a position overlapping end 19, but also at other portions. Furthermore, the film thickness within second portion 202 may be changed depending on the application. That is, film thickness t2 of second portion 202 does not have to be uniform. Two or more second portions 202 are preferably provided near the end of wiring board 200, and first portion 201 is preferably provided between second portions 202.

[0030] Although FIG. 3 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.

[0031] Wiring suitable for a band 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 for transmitting single-ended signals such as control signals and response signals.

[0032] 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.

[0033] 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.

[0034] The configuration of wiring board 200 will now be described in more detail.

[0035] For example, insulating resin can be used as the insulating part 16. Examples of insulating resin include epoxy resin such as glass epoxy, imide resin, phenol resin, cyanate resin, etc. The insulating part 16 may contain a filler. Examples of the filler to be contained include silica, kaolin, talc, alumina, etc. Also, these may be mixed. In addition to the filler, 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 adhesive 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. Here, the hardness may be any hardness index such as Vickers hardness, Rockwell hardness, Brinell hardness, Leeb hardness, Shore hardness, etc. Also, it is preferable that the Young's modulus is higher than that of the substrate 12, the adhesive layer 14a, the coating layer 14b, and the shield layer 15 that constitute the wiring board 200. The thickness of the insulating part 16 is preferably thicker than that of the substrate 12 and the shield layer 15, but is not limited thereto.

[0036] 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 suitable to directly pattern it by various printing methods such as screen printing and inkjet printing, and screen printing is preferred. 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.

[0037] 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 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.

[0038] 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.

[0039] 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, and a slit formed to extend in the Y direction can be formed as necessary. In addition, a shape in which a plurality of shapes are selected and arranged from among these shapes may be used. Among these, polygons such as a square and a hexagon are preferable. If the shape of the openings is a polygon, the variation in the width of the non-opening portion can be suppressed, so that the return path of the radiation noise is uniform, and the radiation noise can be suppressed more efficiently. The opening ratio of the shield layer 15 is preferably 60% or more. If the opening ratio is less than 60%, the flexibility may be deteriorated, but it is not necessary to provide openings and a solid shape may be used.

[0040] The protective layer 18 will be described in detail. The protective layer 18 may be made of any resin having insulating properties, such as a thermosetting resin, a UV-curable resin, or a coating agent made of a resin solution in which a cured film component is dispersed in a solvent. Examples of the thermosetting resin include phenol resin, acrylic resin, epoxy resin, polyamide resin, polyamideimide resin, polyimide resin, melamine resin, silicone resin, and acrylic-modified silicone resin. Examples of the UV-curable resin include epoxy acrylate resin, polyester acrylate resin, and methacrylate-modified products thereof. Examples of the resin solution include polyester urethane resin and polyamideimide resin dissolved in an organic solvent.

[0041] If necessary, color pigments, flame retardants, viscosity modifiers, dust prevention agents, curing accelerators, and other known additives may be added. Among these, it is preferable to use a coating agent made of a resin solution in which the cured film components are dispersed in a solvent, from the viewpoint of small shrinkage due to the curing reaction and suppression of warping. Among them, a coating agent in which a flexible and heat-resistant polyamide-imide resin is dissolved in a solvent is more preferable.

[0042] A known method can be selected as the method for forming the protective layer 18. For example, there are methods such as bar coating, slit coating, spray coating, jet dispenser, and screen printing, in which a liquid resin composition is formed as a coating film to form a cured film, and a method of attaching a sheet after forming the shield layer 15. When applying polyamide-imide resin using the slit coating method, the thickness and cross-sectional shape of the protective layer 18 change depending on the opening area of ​​the slit, the coating speed, and the viscosity of the coating liquid. Taking a coating liquid having a solid content concentration of 14% by weight of polyamide-imide resin as an example, when coating is performed at room temperature at 60 mm per second using a slit of 0.4 mm x 20 mm, the viscosity of the coating liquid is preferably 40 Pa·s or more and 60 Pa·s or less at a shear rate of 10 / s. If it is less than 40 Pa·s, the coating liquid after coating tends to flow, and if it is more than 60 Pa·s, the liquid does not drain well from the slit, and the coating film may not become a continuous film.

[0043] As a method for forming a cured film after coating, a method can be appropriately selected according to the material, and for example, heat curing, ultraviolet curing, electron beam curing, etc. can be adopted. In order to suppress the flow of the coating itself and moisture absorption, it is desirable to perform provisional curing immediately after coating formation. In this embodiment, provisional curing is performed at 120°C within about 15 seconds after completion of coating, and then main curing is performed to complete the coating.

[0044] The substrate 12, the adhesive layer 14a, and the coating layer 14b will be described in detail below.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Next, the covering layer 14b will be described in detail. For example, insulating resin can be used as the covering layer 14b. Examples of the insulating resin used for the covering layer 14b include so-called engineering plastics. That is, examples of other insulating resins used for the covering layer 14b include polypropylene, cross-linked polyethylene, polyester, polybenzimidazole, polyamide, polyimide, polyimideamide, and polyetherimide. Examples of the insulating resin used for the covering layer 14b include 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.

[0051] 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.

[0052] 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.

[0053] 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 flexibility 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.

[0054] <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.

[0055] The evaluation methods for the wiring boards according to the examples and comparative examples will be described below.

[0056] (1) Evaluation of the durability of the shielding layer 5, wiring board 200 is placed so as to run over fixed plate 31, and one end is fixed with end fixture 32. It is bent with a bending radius of 3 mm so that the bending line is parallel to the board width direction, and is run over movable plate 33 arranged opposite fixed plate 31, and the other end is fixed with end fixture 32. Movable plate 33 is repeatedly moved with a drive stroke of ±2.6 mm and a drive frequency of 1 Hz, and the number of operations at which damage to the shielding layer (disconnection, cracks, peeling, etc.) was confirmed was evaluated according to the following criteria. A: No damage after over 10 million uses B: Breaks after more than 5 million uses but less than 10 million uses C: Broken after more than 1 million uses but less than 5 million uses D: Broken in less than 1 million uses

[0057] The ratings of A, B, and C indicate that the improvement in shielding durability is achieved by providing a difference in thickness of protective layer 18, which is a feature of the present invention, while the rating of D is equivalent to the case where the difference in thickness of protective layer 18 specified in the present invention is not provided, indicating that no improvement in the durability of shielding layer 15 is observed.

[0058] (2) Evaluation of wiring board flexibility As shown in Fig. 6, 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

[0059] Example 1 1 to 4, a wiring board 200 was fabricated. 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 lines 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, 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 adjacent signal lines 22, thereby obtaining a 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.

[0060] Next, the coverlay 14 is formed on the wiring layer 13. An adhesive agent having a thickness of 25 μm was used as the adhesive layer 14a, and a coverlay (CEAM0525KA manufactured by Arisawa Manufacturing Co., Ltd.) having a thickness of 15 μm was used as the coating layer 14b, giving a total thickness of 37.5 μm.

[0061] Next, a 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., using a screen printer (MT-320T manufactured by Micro-Tec Co., Ltd.) to a thickness of 5 μm. A diamond mesh-shaped pattern with a line width of 58 μm and openings of 2000 μm in the X direction and 500 μm in the Y direction was formed so that the longitudinal direction of the openings was parallel to the signal line 22.

[0062] Further, a protective layer 18 was formed on the shield layer 15. The protective layer 18 was formed by applying polyamideimide (product name: Viromax HR-16NN) manufactured by Toyobo MC Co., Ltd., using a slit coater (product name: 350PCS-SM300ΩX) manufactured by Musashi Engineering Co., Ltd. The width of the slit was equal to or slightly larger than the width of the shield layer 15 in the Y direction, and the material was discharged while moving in the X direction to form a coating film. At this time, the application conditions were adjusted so that the first portion 201 of the protective layer 18 had a film thickness t1 of 10 μm from the upper surface 15a of the shield layer 15, and the second portion 202 had a film thickness t2 of 20 μm from the upper surface 15a of the shield layer 15. The second portion 202 was arranged in a pattern of uniform thickness and height in the width direction of the wiring board 200. This pattern was called pattern 1.

[0063] More specifically, the main coating conditions are the material discharge speed (ml / sec), the slit nozzle-work gap (μm), and the nozzle movement speed (mm / sec). In the second portion 202, the slit nozzle-work gap was made larger than in the first portion 201, the nozzle movement speed was made slower, and an area 3 mm wide in the X direction was coated. In both the first portion 201 and the second portion 202, a thick wet coating film was formed taking into account the solid content concentration of the coating material, and then it was quickly temporarily cured at 120°C for 5 minutes, and then fully cured in a drying furnace at 200°C for 30 minutes, thereby removing the solvent components in the coating film and forming a film thickness t1 and film thickness t2 consisting only of solid content.

[0064] The following steps may be selected for forming the first portion 201 and the second portion 202. That is, the entire region is coated with a film thickness t1 using a slit coater, and the coating is pre-dried, and then the second portion 202 is coated again, and pre-dried and fully dried. Alternatively, the first portion 201 may be coated using a slit coater, and the second portion 202 may be coated using a jet dispenser (e.g., AeroJet manufactured by Musashi Engineering Co., Ltd.), and then pre-dried and fully dried, or the first portion 201 may be coated and pre-dried using a slit coater, and then the second portion 202 may be coated and pre-dried using a jet dispenser, and then pre-dried and fully dried.

[0065] Finally, a reinforcing plate (FR-4) made of 400 μm thick glass epoxy and 60 μm thick adhesive was attached under base material 12 to serve as insulating section 16, thereby obtaining wiring board 200 of Example 1.

[0066] Example 2 The application conditions were adjusted so that film thickness t2 of second portion 202 of protective layer 18 was 15 μm. Other than that, the same formation as in Example 1 was carried out to obtain wiring board 200 of Example 2.

[0067] Example 3 The application conditions were adjusted so that film thickness t2 of second portion 202 of protective layer 18 became 11 μm. Other than that, the formation was performed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 3.

[0068] Example 4 The application conditions were adjusted so that the width of second portion 202 of protective layer 18 was 5 mm. Other than that, the formation was performed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 4.

[0069] Example 5 The application conditions were adjusted so that the thickness t1 of first portion 201 of protective layer 18 was 3 μm, and the thickness t2 of second portion 202 was 4 μm. Other than that, the same formation as in Example 1 was performed to obtain wiring board 200 of Example 5.

[0070] Example 6 The application conditions were adjusted so that the thickness t1 of first portion 201 of protective layer 18 was 50 μm, and the thickness t2 of second portion 202 was 60 μm. Other than that, the same formation as in Example 1 was performed to obtain wiring board 200 of Example 6.

[0071] Example 7 FIG. 7 is a top view illustrating a wiring board 200 of Example 7. Signal lines and ground lines are omitted. The first portion 201 was coated using a slit coater by adjusting the coating conditions so that the film thickness t1 was 10 μm. The second portion 202 was coated using a jet dispenser by combining line-shaped discharges, and as shown in the second portion 202 of FIG. 7, the strip-shaped region extending in the Y direction was patterned so that the center portion had a width of 3 mm in the X direction and both ends had a width of 5 mm in the X direction. This pattern was called pattern 2. The film thickness t2 was 15 μm. The rest of the structure was formed in the same manner as in Example 1 to obtain the wiring board 200 of Example 7.

[0072] Example 8 FIG. 8 is a diagram for explaining a wiring board 200 of Example 8. FIG. 8(a) is a top view of the wiring board 200 of Example 8, and FIG. 8(b) is a cross-sectional view taken along the line C-C' in FIG. 8(a). In FIG. 8(b), the signal line and the ground line are omitted. This shows a case where the insulating part 16 is disposed inside the end of the substrate 12. The first part 201 of the protective layer 18 was applied by adjusting the application conditions so that the film thickness t1 was 10 μm using a slit coater. The second part 202 was applied by combining line-shaped discharge using a jet dispenser, and the second part 202 was patterned so that the film thickness of the central part was 15 μm and the film thickness of both ends was 20 μm in the band-shaped region extending in the Y direction. This pattern was called pattern 3. The rest of the wiring board 200 of Example 8 was obtained by forming the wiring board 200 in the same manner as in Example 1.

[0073] Example 9 FIG. 9 is a top view illustrating wiring board 200 of Example 9. Signal lines and ground lines are omitted from the illustration. The figure shows a case where insulating portion 16 is disposed inside the end of substrate 12. Second portion 202 of protective layer 18 was applied using a jet dispenser so as to overlap the entire periphery of end 19 of insulating portion 16. This pattern was called pattern 4. The rest of the process was formed in the same manner as in Example 2, thereby obtaining wiring board 200 of Example 9.

[0074] Example 10 The application conditions were adjusted so that film thickness t2 of second portion 202 of protective layer 18 became 25 μm. Other than that, the formation was performed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 10.

[0075] Example 11 The application conditions were adjusted so that film thickness t2 of second portion 202 of protective layer 18 became 10.5 μm. Other than that, the formation was performed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 11.

[0076] Example 12 The application conditions were adjusted so that the width of second portion 202 of protective layer 18 was 5.5 mm. Other than that, the formation was performed in the same manner as in Example 1, thereby obtaining wiring board 200 of Example 12.

[0077] (Example 13) The application conditions were adjusted so that the thickness t1 of first portion 201 of protective layer 18 was 2 μm, and the thickness t2 of second portion 202 was 4 μm. Other than that, the same formation as in Example 1 was performed to obtain wiring board 200 of Example 13.

[0078] Example 14 The application conditions were adjusted so that the thickness t1 of first portion 201 of protective layer 18 was 55 μm and the thickness t2 of second portion 202 was 65 μm. Other than that, the same formation as in Example 1 was performed to obtain wiring board 200 of Example 14.

[0079] Comparative Example 1 The coating conditions were adjusted so that the thickness t1 of the first portion 201 and the thickness t2 of the second portion 202 of the protective layer 18 were both 10 μm. Otherwise, the wiring board was formed in the same manner as in Example 1, to obtain a wiring board of Comparative Example 1.

[0080] Comparative Example 2 The application conditions were adjusted so that the thickness t1 of the first portion 201 of the protective layer 18 was 20 μm, and the thickness t2 of the second portion 202 was 10 μm. Otherwise, the wiring board of Comparative Example 2 was formed in the same manner as in Example 1.

[0081] (Evaluation Results) The evaluation results of Examples 1 to 14 and Comparative Examples 1 and 2 are shown in Table 1. The shielding durability and flexibility were good in wiring boards 200 of Examples 1 to 14. In contrast, in Comparative Examples 1 and 2, the thickness t1<thickness t2 was not satisfied, and therefore the shielding durability or flexibility was insufficient.

[0082] [Table 1]

[0083] <Second embodiment> Next, a digital camera 600, which is an imaging device, will be described with reference to FIG. 10 as an example of an electronic device using any of the wiring boards shown in the first embodiment.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] The above-described embodiment can be modified as appropriate without departing from the technical concept.

[0093] For example, a plurality of embodiments may be combined, and some details of at least one embodiment may be deleted or replaced.

[0094] 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.

[0095] 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.

[0096] The disclosure of the present invention is given below.

[0097] (Configuration 1) 1. A flexible wiring board comprising: a substrate, a signal line formed on one surface of the substrate, a shielding layer overlapping the signal line in a planar view, and a protective layer covering the shielding layer, and having an insulating portion on the other surface of the substrate, wherein the protective layer has a first portion having a thickness t1 from a top surface of the shielding layer to an outermost surface of the protective layer, and a second portion having a thickness t2 from the top surface of the shielding layer to the outermost surface of the protective layer that is larger than the thickness t1, and the protective layer overlaps at least a portion of an end of the insulating portion in a planar view in the second portion.

[0098] (Configuration 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.

[0099] (Configuration 3) 3. The flexible wiring board according to claim 1, wherein the insulating portion is a reinforcing plate having a thickness greater than that of the base material.

[0100] (Configuration 4) 4. The flexible wiring board according to claim 1, wherein the shielding layer has a mesh shape.

[0101] (Configuration 5) 5. The flexible wiring board according to any one of configurations 1 to 4, comprising a plurality of the second portions, the first portions being provided between the second portions.

[0102] (Configuration 6) 6. The flexible wiring board according to any one of configurations 1 to 5, wherein the thickness t1 and the thickness t2 satisfy 0.5 μm≦t2−t1≦20 μm.

[0103] (Configuration 7) 7. The flexible wiring board according to any one of configurations 1 to 6, wherein the film thickness t1 is 1 μm or more and 60 μm or less.

[0104] (Configuration 8) 8. The flexible wiring board according to any one of configurations 1 to 7, wherein the film thickness t2 is 2 μm or more and 80 μm or less.

[0105] (Configuration 9) 9. The flexible wiring board according to any one of configurations 1 to 8, wherein the thickness t2 is three times or less than the thickness t1.

[0106] (Configuration 10) 10. The flexible wiring board according to any one of configurations 1 to 9, wherein the insulating portion has a higher Young's modulus than the base material.

[0107] (Configuration 11) 11. The flexible wiring board according to any one of configurations 1 to 10, wherein the second portion includes a region where the flexible wiring board is bent.

[0108] (Configuration 12) 12. The flexible wiring board according to any one of configurations 1 to 11, wherein the height or width of the protective layer is not uniform in the second portion.

[0109] (Configuration 13) 13. The flexible wiring board according to any one of configurations 1 to 12, wherein the protective layer contains polyamideimide or polyimide.

[0110] (Configuration 14) 14. The flexible wiring board according to any one of configurations 1 to 13, wherein the insulating portion is made of glass epoxy.

[0111] (Configuration 15) 15. The flexible wiring board according to any one of configurations 1 to 14, wherein the hardness of the insulating portion is higher than the hardness of the shielding layer.

[0112] (Configuration 16) The flexible wiring board described in any one of configurations 1 to 15, 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.

[0113] (Method 1) 17. A method for manufacturing a wiring board according to any one of configurations 1 to 16, wherein the shielding layer is formed by screen printing.

[0114] (Module 1) 17. An electronic module comprising: a wiring board according to any one of claims 1 to 16; a rigid wiring board to which an end of the wiring board is connected; and an electronic component mounted on the rigid wiring board.

[0115] (Module 2) The electronic module described in Module 1, characterized in that the electronic components include an image sensor.

[0116] (Unit 1) An electronic unit comprising: an electronic module according to module 1 or 2; and a drive device that moves the rigid wiring board.

[0117] (Equipment 1) An electronic device comprising: an electronic module according to module 1 or 2; and a circuit board to which an end of the wiring board other than the end is connected, wherein a processor is mounted on the circuit board for processing signals output from the electronic component.

[0118] (Equipment 2) An electronic device comprising: an electronic module according to Module 1 or 2; and a housing that houses the electronic module, wherein the wiring board is housed in the housing in a bent state, and the shielding layer is provided on an outer surface of the bent surfaces of the wiring board. [Explanation of symbols]

[0119] 12 Base material 15 Shielding Layer 16 Insulation 18 Protective layer 19 End 22 Signal Line 200 Flexible wiring board 201 Part 1 202 Part 2

Claims

1. A flexible wiring board having a substrate, a signal line formed on one surface of the substrate, a shielding layer overlapping the signal line in a planar view, and a protective layer covering the shielding layer, the flexible wiring board having an insulating portion on the other surface of the substrate, the protective layer has a first portion having a thickness t1 from an upper surface of the shielding layer to an outermost surface of the protective layer, and a second portion having a thickness t2 from the upper surface of the shielding layer to the outermost surface of the protective layer that is greater than the thickness t1; The flexible wiring board, wherein the protective layer overlaps at least a portion of an end of the insulating portion in a plan view in the second portion.

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. 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 base material.

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

5. 2. The flexible wiring board according to claim 1, further comprising a plurality of the second portions, the first portions being provided between the second portions.

6. 2. The flexible wiring board according to claim 1, wherein the thickness t1 and the thickness t2 satisfy 0.5 μm≦t2−t1≦20 μm.

7. 2. The flexible wiring board according to claim 1, wherein the thickness t1 is 1 μm or more and 60 μm or less.

8. 2. The flexible wiring board according to claim 1, wherein the thickness t2 is 2 μm or more and 80 μm or less.

9. 2. The flexible wiring board according to claim 1, wherein the thickness t2 is equal to or smaller than three times the thickness t1.

10. The flexible wiring board according to claim 1 , wherein the insulating portion has a Young's modulus higher than that of the base material.

11. The flexible wiring board according to claim 1 , wherein the second portion includes a region where the flexible wiring board is bent.

12. The flexible wiring board according to claim 1 , wherein the height or width of the protective layer is not uniform in the second portion.

13. The flexible wiring board according to claim 1 , wherein the protective layer contains polyamideimide or polyimide.

14. 2. The flexible wiring board according to claim 1, wherein the insulating portion is made of glass epoxy.

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, 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.

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

18. A wiring board according to any one of claims 1 to 16, a rigid wiring board to which an end of the wiring board is connected; and an electronic component mounted on the rigid wiring board.

19. 20. The electronic module of claim 18, wherein the electronic component comprises an image sensor.

20. An electronic module according to claim 18; and a drive device that moves the rigid wiring board.

21. An electronic module according to claim 19; 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.

22. An electronic module according to claim 19; 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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