JP2011066329A - Shield film, shielded wiring board including the same, ground connection method in the shield film - Google Patents

Abstract

A shield film that can be easily connected to a ground without exposing a ground conductor of a substrate to which the shield film is to be attached, and a shield function and an impedance control function in one step using the shield film. A shield wiring board that can be provided and a ground connection method using the shield film.
A shield film 20 connected to a conductive member 30 by heating and pressurization is formed of a resin having a melting point higher than the temperature at the time of heating, and conductive particles 35 protruding from a conductive adhesive layer 33 at the time of connection. The cover film 25 is formed with a layer thickness L1 thinner than the average protrusion length L2, and the metal thin film layer 24 and the adhesive layer 23 are sequentially laminated on the cover film 25.
[Selection] Figure 1

Description

  The present invention relates to a shield film used for a substrate having a conductor such as a flexible flat cable, a shield wiring board having the shield film, and a ground connection method in the shield film.

  2. Description of the Related Art Conventionally, a substrate having a conductor such as a flexible flat cable has been widely used for connection inside or between devices in various electronic devices such as televisions, videos, mobile phones, and OA devices represented by personal computers.

  In addition, electronic devices have been required to increase the speed of telecommunications due to the progress of the information society in recent years.Accordingly, in order to reduce unnecessary radiation from external electric signals and external noise, A shield film is attached to a substrate having a conductor such as a flexible flat cable. Furthermore, since the above-described substrate needs impedance matching with the connected device, an impedance control film having a function of controlling impedance is attached.

  For example, in Patent Document 1, as shown in FIG. 6, a plurality of conductors composed of a signal conductor 51 and a ground conductor 52 are arranged in parallel in the width direction, and are thick with a foamed insulator 54 having an insulating adhesive layer 53. A flexible flat cable 50 is disclosed which is sandwiched between both sides in the vertical direction and then laminated and further sandwiched between both sides by a metal layer 56 having a conductive adhesive layer 55. In addition, an insulating film 57 is provided on the metal layer 56.

  The flexible flat cable 50 having such a configuration can adjust the characteristic impedance by combining the dielectric constant of the foamed insulator 54 and the dielectric constant of air. The flexible flat cable 50 has a shielding effect due to the metal layer 56.

  For example, in Patent Document 2, as shown in FIG. 7, a plurality of conductors including signal conductors 61 and ground conductors 62 are arranged in parallel in the width direction on a base film 63, and an insulating layer 64 is provided. In addition, the impedance control film includes an opening metal thin film layer 66 having a conductive adhesive layer 65 and an insulating film 67, and includes a non-open metal thin film layer 69 having a conductive adhesive layer 68 and an insulating film 70. An impedance control shield wiring board 60 in which a shield film is sequentially provided is disclosed.

  The impedance control shield wiring board 60 having such a configuration has an impedance control effect by the opening metal thin film layer 66 and has a shielding effect by the non-opening metal thin film layer 69.

JP 2003-31033 A JP 2006-24824 A

  However, as shown in FIG. 6, in the flexible flat cable 50 according to Patent Document 1, in order to set the potential of the metal layer 56 to the ground potential, the conductive adhesive layer 55, the foamed insulator 54, and the adhesive layer 53 are bothered. A non-insulating portion 58 was previously formed in a part of the inside, and the metal layer 56 and the ground conductor 52 had to be connected by a conductive adhesive layer 59 filling the inside.

  Further, in order for the flexible flat cable 50 to obtain both the impedance effect and the shielding effect, at least two steps of processing the foamed insulator 54 and thereafter sandwiching the foamed insulator 54 by the metal layer 56 are required.

  Further, as shown in FIG. 7, in the impedance control shield wiring board 60 according to Patent Document 2, in order to set the potential of the opening metal thin film layer 66 to the ground potential, a part of the insulating layer 64 is not previously used. It is necessary to connect the opening metal thin film layer 66 and the ground conductor 62 by the conductive adhesive layer 65 that is provided with the insulating portion 71 and fills the insulating portion 71.

  Further, in order for the impedance control shield wiring board 60 to obtain both the impedance effect and the shield effect, at least two steps of forming both the open metal thin film layer and the non-open metal thin film layer are required.

  As described above, in the flexible flat cable 50 according to Patent Document 1 and the impedance control shield wiring board 60 according to Patent Document 2, in order to obtain a shielding effect and an impedance control effect, a ground conductor is exposed by bothering the provision of a non-insulating portion. In other words, there is a problem that it takes time and cost, and that at least two steps of forming a layer having a shielding effect and a layer having an impedance control effect are necessary.

  Therefore, the present invention provides a shield film that can be easily connected to the ground without exposing the ground conductor of the substrate to which the shield film is attached, and the shield function and impedance control in one step using the shield film. An object of the present invention is to provide a shield wiring board capable of having a function and a ground connection method using the shield film.

  The shield film of the present invention is a shield film that is connected to a conductive member provided in contact with a metal layer for connection to an external ground member and a conductive adhesive layer containing conductive particles by heating and pressurization. And formed by a resin that is softened by heating and having a layer thickness that is thinner than the average protruding length of the conductive particles protruding from the conductive adhesive layer after being connected by heating and pressing. And a cover film adhered to the conductive adhesive layer, and a metal thin film layer and an adhesive layer sequentially laminated on the cover film.

  According to the above configuration, when the conductive member is connected to the shield film composed of the cover film, the metal thin film layer, and the adhesive layer by heating and pressurizing, the cover film formed of the resin in the shield film is heated. Furthermore, since the layer thickness of the cover film in connection is thinner than the average protruding length of the conductive particles protruding from the conductive adhesive layer in the conductive member, the conductive particles protruding from the conductive adhesive layer by pressurization are The cover film in the shield film can be penetrated to reach the metal thin film layer. As a result, the potential of the metal thin film layer in the shield film can be set to the ground potential via the conductive particles, so that the ground conductor in the substrate to which the shield film is attached and the metal in the shield film as in the past. There is no need to connect the thin film layer. Therefore, there is no need to process the substrate in advance to expose the ground conductor, and processing costs are not required. Further, since the conductive member is simply connected to the shield film, the shield film can be easily grounded at a desired position even when a long substrate is used.

  In the shield film of the present invention, an intervening layer is further adhered to the adhesive layer, and the intervening layer is adhered to a substrate having a conductor, thereby controlling the impedance of the substrate having the conductor. You may do it.

  According to said structure, the impedance of the board | substrate which has a conductor can be adjusted by adjusting the thickness of an intervening layer. Therefore, the shield film has a layer for adjusting the impedance of the substrate having a conductor and a layer having a shielding effect, and the shielding effect is also provided on the substrate by only one step of attaching the shielding film to the substrate. A control effect can also be given.

  In the shield film of the present invention, the substrate may be a flexible flat cable.

  According to said structure, the shield film affixed on a flexible flat cable can be provided.

  Moreover, this invention is a shield wiring board which has a board | substrate which has a conductor, and the shield film described above.

  According to said structure, the shield wiring board with which the shield film was affixed can be provided.

Further, the present invention is a shield film ground connection method, comprising: a cover film formed of a resin; a metal thin film layer and an adhesive layer sequentially laminated on the cover film; There,
A conductive member provided in contact with a metal layer connected to an external ground member and a conductive adhesive layer containing conductive particles is pressed while being heated at a temperature at which the resin softens, and the conductive adhesive layer and the conductive layer It is a ground connection method for a shield film, wherein the conductive particles protruding longer than the layer thickness of the cover film are connected to the ground by reaching the metal thin film layer by bonding the cover film. .

  According to the above ground connection method, when the conductive member is connected to the shield film composed of the cover film, the metal thin film layer, and the adhesive layer by heating and pressing, the cover film formed of the resin in the shield film is Since the thickness of the cover film is softened by heating, and the thickness of the cover film is thinner than the average protruding length of the conductive particles protruding from the conductive adhesive layer in the conductive member, the conductive protruding from the conductive adhesive layer by pressing The particles can penetrate the cover film in the shield film and reach the metal thin film layer. As a result, the potential of the metal thin film layer in the shield film can be set to the ground potential via the conductive particles, so that the ground conductor in the substrate to which the shield film is attached and the metal in the shield film as in the past. There is no need to connect the thin film layer. Therefore, there is no need to process the substrate in advance to expose the ground conductor, and processing costs are not required. Further, since the conductive member is simply connected to the shield film, the shield film can be easily grounded at a desired position even when a long substrate is used.

  According to the shield film of the present invention, since the potential of the metal thin film layer in the shield film can be set to the ground potential via the conductive particles, there is no need to process the substrate in advance and expose the ground conductor, There is no processing cost. Moreover, since only the conductive member is connected to the shield film, the shield film can be easily grounded at a desired position.

FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2 in the shield wiring board according to the embodiment of the present invention. It is a figure which shows the external appearance of the shield wiring board which concerns on embodiment of this invention. FIG. 3 is a cross-sectional view taken along the line B-B ′ of FIG. 2 in the shield wiring board according to the embodiment of the present invention. (A) is a figure which shows before the connection of a conductive member and a shield film in the ground connection method of the shield film which concerns on embodiment of this invention. (B) is a figure which shows the connection of an electroconductive member and a shield film in the ground connection method of the shield film which concerns on embodiment of this invention. It is a figure which shows the manufacturing method of the shield film which concerns on embodiment of this invention. It is a figure which shows the cross section of the flexible flat cable which concerns on patent document 1. FIG. It is a figure which shows the cross section of the impedance control shield wiring board concerning patent document 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(overall structure)

  As shown in FIG. 1, the shield film 20 of the present invention includes a conductive member 30 provided with a metal layer 32 for connection to an external ground member and a conductive adhesive layer 33 including conductive particles 35 in a contact state. The shield film 20 connected by heating and pressurization, formed of a resin softened by heating, and the average of the conductive particles 35 protruding from the conductive adhesive layer 33 when connected by heating and pressurization A cover film 25 that is formed to have a layer thickness L1 that is thinner than the protruding length L2, and that is adhered to the conductive adhesive layer 33, and a metal thin film layer 24 and an adhesive layer 23 that are sequentially laminated on the cover film 25. Have.

  Further, as shown in FIG. 1, the shield film 20 of the present invention is affixed to a substrate having a conductor such as a flexible flat cable 10 to reduce unnecessary radiation from an electric signal and noise from the outside. It has the role of adjusting the impedance so that impedance mismatch does not occur between the cable 10 and the connected device.

  Furthermore, the shield film 20 of the present invention can be grounded by being connected to the conductive member 30 connected to the external ground member by heating and pressing.

Here, “connection” means that two or more things are at least electrically connected. In this case, the shield film 20 and the conductive member 30 are at least electrically connected.
(Conductive member 30)

First, the conductive member 30 connected to the shield film 20 of the present invention will be described. As shown in FIG. 4, the conductive member 30 is provided with a metal layer 32 adhered in contact with a conductive adhesive layer 33 including conductive particles 35, and a plating 31 such as gold plating or tin plating thereon. It has a configuration.
(Conductive adhesive layer 33)

The conductive adhesive layer 33 included in the conductive member 30 is formed as a mixture of conductive particles 35 and an adhesive 34 (acrylic resin or the like). That is, the conductive adhesive layer 33 is obtained by dispersing conductive particles 35 in an adhesive 34 such as an acrylic resin. The electrical connection of the conductive adhesive layer 33 is realized by continuously contacting one or more conductive particles 35 in the adhesive 34 in the thickness direction of the conductive adhesive layer 33. It is held by the adhesive force of 34.
(Adhesive 34)

  Examples of the adhesive 34 included in the conductive adhesive layer 33 include acrylic resins, epoxy resins, silicon resins, thermoplastic elastomer resins, rubber resins, and polyester resins. The adhesive 34 may be a single substance or a mixture of the above resins.

The adhesive 34 may further include a tackifier. Examples of the tackifier include tackifiers such as fatty acid hydrocarbon resins, C5 / C9 mixed resins, rosin, rosin derivatives, special resins, terpene resins, aromatic hydrocarbon resins, and thermally reactive resins.
(Conductive particles 35)

  Part or all of the conductive particles 35 included in the conductive adhesive layer 33 are formed of a metal material. For example, the conductive particles 35 are copper powder, silver powder, nickel powder, silver-coated copper powder (Ag-coated Cu powder), gold-coated copper powder, silver-coated nickel powder (Ag-coated Ni powder), and gold-coated nickel powder. Yes, these metal powders can be produced by a water atomization method, a carbonyl method, or the like. In addition to the above, particles obtained by coating a metal powder with a resin and particles obtained by coating a resin with a metal powder can also be used. The conductive particles 35 are preferably Ag-coated Cu powder or Ag-coated Ni powder. This is because the conductive particles 35 with improved conductivity can be obtained from an inexpensive material.

Further, as shown in FIG. 4A, the conductive particles 35 are in contact with the metal layer 32 and partly protrudes from the conductive adhesive layer 33 on the side to be attached to the shield film 20. .
(Metal layer 32)

  The metal layer 32 included in the conductive member 30 is a metal such as nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, and an alloy including any one or more of these materials. Made of material.

  Further, as shown in FIG. 2, the metal layer 32 is connected to an external ground member such as a housing, and the potential thereof is kept at the ground potential.

Further, the metal layer 32 is plated with gold 31 or tin.
(Shield film 20)

As shown in FIG. 1, the shield film 20 of the present invention connected to the ground using the conductive member 30 includes an intervening layer 22 having an adhesive layer 21, a metal thin film layer 24 having an adhesive layer 23, and a cover film. And 25 are sequentially stacked.
(Cover film 25)

  The cover film 25 included in the shield film 20 is formed of an epoxy resin, a polyester resin, an acrylic resin, a phenol resin, a urethane resin, or a mixture thereof.

  Here, the circular part E in FIG. 1 is an enlarged part of the state where the conductive adhesive layer 33 in the conductive member 30 is bonded to the cover film 25.

  As shown in a circle E in FIG. 1, when the conductive member 30 is connected to the shield film 20, the conductive adhesive layer 33 in the conductive member 30 is bonded to the cover film 25 in the shield film 20. At the time of adhesion, the cover film 25 is heated from the conductive member 30 side and softened.

  Moreover, the epoxy resin that forms the cover film 25 is formed of a resin that is softened at a heating temperature when the conductive member 30 is connected to the shield film 20, and the softening temperature of the resin is 100 ° C. to 140 ° C. Range.

Further, as shown in a circle E in FIG. 1, conductive particles 35 are contained in the conductive adhesive layer 33 in the conductive member 30. In connection between the shield film 20 and the conductive member 30, a part of the conductive particles 35 protrudes from the conductive adhesive layer 33, and the average protrusion length L <b> 2 of the conductive particles 35 at the protrusions of the cover film 25 is It is set to be longer than the layer thickness L1.
(Metal thin film layer 24)

  The metal thin film layer 24 included in the shield film 20 has a shielding effect for reducing unnecessary radiation from an electric signal and noise from the outside.

  In addition, the metal thin film layer 24 includes conductive particles in the conductive adhesive layer 33 that has broken through the cover film 25 when the conductive member 30 connected to the external ground member is connected to the shield film 20 by heating and pressing. It is connected to the conductive member 30 via 35. Thereby, the shield film 20 can be grounded by the conductive member 30.

Examples of the metal material for forming the metal thin film layer 24 include nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, and an alloy containing any one or more of these materials. Can be mentioned. The metal material and thickness of the metal thin film layer 24 may be appropriately selected according to the required shielding effect and repeated bending / sliding resistance, but the thickness may be about 3 μm to 20 μm. Moreover, Preferably they are 6 micrometers-15 micrometers, More preferably, they are 9 micrometers-12 micrometers. If the thickness is less than 3 μm, sufficient transmission characteristics cannot be obtained, and if it exceeds 20 μm, flexibility becomes a problem. Furthermore, although the metal thin film layer 24 can be a metal foil, plating, or the like, a metal foil is preferable.
(Intervening layer 22)

The intervening layer 22 included in the shield film 20 is composed of polyethylene terephthalate, polyethylene, polypropylene, foamed polyethylene terephthalate, foamed polyethylene, foamed polypropylene, non-woven fabric, and the like, and is laminated on the metal thin film layer 24 with the adhesive layer 23. Further, the shield film 20 is made thicker. Further, by adjusting this thickness, when the shield film 20 is attached to the flexible flat cable 10, the impedance of the flexible flat cable 10 can be adjusted. Further, the intervening layer 22 can be adhered to the flexible flat cable 10 by the adhesive layer 21. With such a configuration, the shield film 20 can affix the intervening layer 22 to the flexible flat cable 10 or the like by adhesion of the adhesive layer 23. Thus, the impedance of the flexible flat cable 10 can be adjusted by adjusting the thickness of the intervening layer 22. Therefore, the shield film 20 is provided with a layer for adjusting the impedance of the flexible flat cable 10 and a layer having a shielding effect, and the flexible flat cable 10 is bonded to the flexible flat cable 10 only in one step. The cable 10 can be given a shielding effect and an impedance control effect.
(Adhesive layers 21 and 23)

  The adhesive layers 21 and 23 included in the shield film 20 are olefin-based, urethane-based, vinyl acetate-based, polyester-based, polyamide-based, rubber-based, acrylic-based thermoplastic resins, phenol-based, epoxy-based, urethane-based, etc. , Melamine-based, polyimide-based, alkyd-based thermosetting resins. The intervening layer 22 can be adhered to the flexible flat cable 10 by the adhesive layer 21. Further, the metal thin film layer 24 can be bonded to the intervening layer 22 by the adhesive layer 23.

When the shield film 20 having the above configuration is used, when the conductive member 30 is connected to the shield film 20 including the cover film 25, the metal thin film layer 24, and the adhesive layer 23 by heating and pressurization, the inside of the shield film 20 The cover film 25 made of the above resin is softened by heating, and the layer thickness L1 of the cover film 25 in connection is more than the average protrusion length L2 of the conductive particles 35 protruding from the conductive adhesive layer 33 in the conductive member 30. Therefore, the conductive particles 35 protruding from the conductive adhesive layer 33 by pressurization can penetrate the cover film 25 in the shield film 20 and reach the metal thin film layer 24. Thereby, since the potential of the metal thin film layer 24 in the shield film 20 can be set to the ground potential via the conductive particles 35, the ground conductor and the shield in the substrate to which the shield film 20 is attached as in the prior art. It is not necessary to connect the metal thin film layer 24 in the film 20. Therefore, there is no need to process the substrate in advance to expose the ground conductor, and processing costs are not required. Further, since only the conductive member 30 is connected to the shield film 20, for example, even when a long substrate is used, the shield film 20 can be easily grounded at a desired position.
(Flexible flat cable 10)

  Next, the flexible flat cable 10 attached to the shield film 20 having the above configuration will be described. As shown in FIG. 1, the flexible flat cable 10 has a plurality of conductors composed of signal conductors 11 and ground conductors 12 arranged in parallel in the width direction on a base film 14, and further provided with an insulating film 13 thereon. It has the structure which was made.

  Both the base film 14 and the insulating film 13 are made of engineering plastic. Examples thereof include resins such as polyethylene terephthalate, polypropylene, cross-linked polyethylene, polyester, polybenzimidazole, polyimide, polyimide amide, polyether imide, and polyphenylene sulfide (PPS). An inexpensive polyester film is preferable when heat resistance is not required, and a polyphenylene sulfide film is preferable when flame resistance is required, and a polyimide film is preferable when heat resistance is required.

  Further, the base film 14, the signal conductor 11 and the ground conductor 12 may be joined by an adhesive, or may be molded by extruding a resin.

  Moreover, as shown in FIG. 3, the reinforcement board 40 is provided in the edge part of the flexible flat cable 10, and the intensity | strength of the connector insertion part of a flexible flat cable is improved.

  In the flexible flat cable 10 having the above configuration, the circuit signal is stabilized by the metal thin film layer 24 in the shield film 20. Furthermore, the flexible flat cable 10 has an electromagnetic shielding effect due to the shield film 20.

  In addition to the flexible flat cable, the shield film 20 can be used for FPC, COF (chip-on-flex), RF (flex printed board), multilayer flexible board, rigid board, etc., but is not necessarily limited thereto.

Further, as shown in FIG. 2, the ground conductor 12 of the flexible flat cable 10 is connected to an external ground member such as a housing of an electronic device to be incorporated, as in the case of the conductive member 30. And the conductive member 30 have the same ground potential. Furthermore, as described above, since the conductive member 30 and the shield film 20 can be set to the same potential via the conductive particles 35, the shield film 20 and the ground conductor 12 can be set to the same ground potential. .
(Shield wiring board 1)

  Next, the shield wiring board 1 comprised from the shield film 20 and the flexible flat cable 10 is demonstrated.

  As shown in FIG. 1 and FIG. 3, the shield wiring board 1 of the present invention is attached to one side or both sides of the flexible flat cable 10 (FFC) with one shield film 20 or wrapped on both sides of the flexible flat cable 10. A conductive member 30 is connected to the shield film 20.

As described above, when the conductive member 30 is connected to the shield film 20, the shield film 20 can be grounded through the conductive member 30 connected to an external ground member such as a housing.
(Ground connection method of shield film 20)

  Next, the ground connection method of the shield film 20 will be described in detail with reference to FIG.

  As shown in FIG. 4, the ground connection method in the shield film 20 of the present invention includes a cover film 25 formed of a resin, and a metal thin film layer 24 and an adhesive layer 23 that are sequentially laminated on the cover film 25. A method for ground connection of the film 20, wherein the conductive member 30 provided in contact with the metal layer 32 connected to the external ground member and the conductive adhesive layer 33 including the conductive particles 35 is at a temperature at which the resin softens. By applying pressure while heating and bonding the conductive adhesive layer 33 and the cover film 25, the conductive particles 35 that protrude longer than the layer thickness L <b> 1 of the cover film 25 reach the metal thin film layer 24 to reach the ground connection. This is a ground connection method of the shield film 20 to be performed.

  First, as shown in FIG. 4A, the conductive member 30 kept at the ground potential is aligned with the shield film 20 and heated from the conductive member 30 side. The heating temperature at this time is set to a range of 100 ° C. to 140 ° C. at which the cover film 25 formed of resin is softened, and the cover film 25 starts to soften by this heating. The heating temperature at this time is preferably 120 ° C. to 135 ° C., and if it is less than 100 ° C., sufficient adhesion cannot be obtained. Moreover, since it will damage the flexible flat cable 10 when it exceeds 140 degreeC, it is unpreferable. Next, after the cover film 25 is heated, the conductive adhesive layer 33 in the conductive member 30 is further adhered to the cover film 25 by applying pressure from the conductive member 30 side toward the shield film 20. At this time, the cover film 25 has adhesiveness due to softening, and the conductive particles 35 protruding from the conductive adhesive layer 33 enter the cover film 25. Here, in the connection between the shield film 20 and the conductive member 30, the average protruding length L2 of the conductive particles 35 protruding from the conductive adhesive layer 33 is longer than the layer thickness L1 of the cover film. By the pressurization from the side, the conductive particles 35 break through the cover film 25 and reach the metal thin film layer 24.

  As a result, as shown in FIG. 4B, the metal layer 32 and the metal thin film layer 24 become conductive through the conductive particles 35, and the potential of the metal thin film layer 24 can be set to the ground potential.

As described above, according to the ground connection method, when the conductive member 30 is connected to the shield film 20 including the cover film 25, the metal thin film layer 24, and the adhesive layer 23 by heating and pressurization, The cover film 25 made of the above resin is softened by heating, and the layer thickness L1 of the cover film 25 in connection is more than the average protrusion length L2 of the conductive particles 35 protruding from the conductive adhesive layer 33 in the conductive member 30. Therefore, the conductive particles 35 protruding from the conductive adhesive layer 33 by pressurization can penetrate the cover film 25 in the shield film and reach the metal thin film layer 24. Thereby, since the potential of the metal thin film layer 24 in the shield film 20 can be set to the ground potential via the conductive particles 35, the ground conductor and the shield in the substrate to which the shield film 20 is attached as in the prior art. It is not necessary to connect the metal thin film layer 24 in the film 20. Therefore, there is no need to process the substrate in advance to expose the ground conductor, and processing costs are not required. Further, since only the conductive member 30 is connected to the shield film 20, for example, even when a long substrate is used, the shield film 20 can be easily grounded at a desired position.
(Method for producing shield film 20)

  Next, the manufacturing method of the shield film 20 is demonstrated using FIG.

  As shown in FIG. 5, the manufacturing method of the shield film 20 according to the present embodiment forms an unwinding step of unwinding the metal thin film layer 24 wound in a roll shape, and forms the cover film 25 on the metal thin film layer 24. A cover film forming step, an adhesive layer forming step for forming the adhesive layer 23 on the metal thin film layer 24, and an intermediate layer forming step for forming the shield film 20 by bonding the intervening layer 22 having the adhesive layer 21 together with the adhesive layer 23. And a winding step of winding the formed shield film 20 into a roll.

  Specifically, first, in the unwinding step, the roll-shaped metal thin film layer 24 set in the unwinding machine 41 is unwound. Thereafter, the unrolled metal thin film layer 24 is moved to the coating device 42 while being guided by the guide roller.

  Next, in the cover film forming step, an epoxy resin or the like is applied to the metal thin film layer 24 by the coating device 42 and dried in the drying furnace 43 to form the cover film 25. After that, it is moved to the coating device 44 while being guided by the guide roller again.

  Next, in the adhesive layer forming step, a thermoplastic resin or a thermosetting resin is applied to the metal thin film layer 24 on which the cover film 25 is formed by a coating device 44 and dried in a drying furnace 45 to be an adhesive layer. 23 is formed.

  Next, in the intervening layer forming step, the intervening layer 22 having the adhesive layer 21 manufactured separately in advance is bonded to the metal thin film layer 24 formed with the cover film 25 and the adhesive layer 23 by the laminating machine 46, The shield film 20 is manufactured.

  Finally, the completed shield film 20 is wound into a roll by the winder 47 while being guided by the guide roller. Thereby, the shield film 20 which concerns on this embodiment can be manufactured.

  The embodiment of the present invention has been described above. Note that the present invention need not be limited to the above-described embodiment.

  For example, in the case of the present embodiment, the cross section of the conductive particles 35 has a circular shape. However, the present invention is not limited to this, and the metal particles 32 are in contact with the conductive particles 35 and the conductive adhesive layer 33 is connected. As long as the average protrusion length L2 from the layer is longer than the layer thickness L1 of the cover film 25, the shape may be circular (an ellipse, an egg shape, etc., with rounded corners), dendrite shape, scale shape It may have any shape such as a needle shape, a chain shape, or a spike shape. In addition, Preferably, circular is good.

  In FIG. 4, the conductive member 30 includes one conductive particle 35 in the thickness direction of the conductive adhesive layer 33, and a plurality of the conductive particles 35 in the width direction of the conductive adhesive layer 33. Although the arrangement is arranged, the present invention is not limited to this. For example, the number of conductive particles 35 included in the thickness direction of the conductive adhesive layer 33 is not limited to one, and a plurality of conductive particles 35 may be formed on the conductive adhesive layer 33 according to the particle diameter of the conductive particles 35. You may arrange | position continuously in a contact state in the thickness direction.

  Further, in the manufacturing method of the shield film 20 in FIG. 5, the intervening layer 22 on which the adhesive layer 21 is formed in advance is bonded to the metal thin film layer 24 on which the cover film 25 and the adhesive layer 23 are formed by the bonding machine 46. However, the present invention is not limited to this, and the intervening layer 22 and the adhesive layer 21 may be sequentially formed on the metal thin film layer 24 on which the cover film 25 and the adhesive layer 23 are formed.

  The embodiments of the present invention have been described above, but only specific examples have been illustrated, and the present invention is not particularly limited. Specific configurations and the like can be appropriately changed in design. Further, the actions and effects described in the embodiments of the present invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to things.

  INDUSTRIAL APPLICABILITY The present invention can be used for a shield film used for a substrate having a conductor such as a flexible flat cable, and a shield wiring board having a shield film.

DESCRIPTION OF SYMBOLS 1 Shield wiring board 10 Flexible flat cable 11 Signal conductor 12 Ground conductor 13 Insulating film 14 Base film 20 Shield film 21 Adhesive layer 22 Intervening layer 23 Adhesive layer 24 Metal thin film layer 25 Cover film 30 Conductive member 33 Conductive adhesive layer 35 Conductivity particle

Claims (5)

A shield film connected by heating and pressurizing to a conductive member provided in a contact state with a metal layer for connecting to an external ground member and a conductive adhesive layer containing conductive particles,
After being formed by the resin softened by heating and connected by the heating and pressurization, and formed with a layer thickness thinner than the average protruding length of the conductive particles protruding from the conductive adhesive layer, A cover film bonded to the conductive adhesive layer;
A metal thin film layer and an adhesive layer sequentially laminated on the cover film;
A shielding film characterized by comprising: An intervening layer is further bonded to the adhesive layer,
The shield film according to claim 1, wherein an impedance of the substrate having the conductor is controlled by bonding the intervening layer to the substrate having the conductor.   The shield film according to claim 2, wherein the substrate is a flexible flat cable. A substrate having a conductor;
The shield film according to any one of claims 1 to 3,
Shield wiring board having A shield film ground connection method comprising: a cover film formed of a resin; and a metal thin film layer and an adhesive layer sequentially laminated on the cover film,
A conductive member provided in contact with a metal layer connected to an external ground member and a conductive adhesive layer containing conductive particles is pressed while being heated at a temperature at which the resin softens, and the conductive adhesive layer and the conductive layer A method for ground connection of a shield film, characterized in that the conductive particles protruding longer than the layer thickness of the cover film reach the metal thin film layer by bonding to a cover film to make a ground connection.