JP5114152B2 - Flexible flat cable and manufacturing method thereof - Google Patents

Description

  The present invention relates to a shielded flexible flat cable, and more particularly to a flexible flat cable that does not require lamination of an external shield and has excellent adhesion, and a manufacturing method that can simplify the manufacturing process. .

  In a flexible flat cable (FFC), in order to prevent radio wave interference from the wiring material, the outer surface of the wiring material is covered with a conductor and an electromagnetic shield layer is provided. How to install this shield layer is an important technical issue.

  FIG.3 and FIG.4 is a figure which shows an example of the conventional flexible flat cable typically (refer patent document 1). 4 (a) and 5 (a) are perspective views, FIG. 4 (b) is a cross-sectional view taken along line MM in FIG. 4 (a), and FIG. 5 (b) is a cross-sectional view taken along line NN in FIG. 5 (a). FIG.

  The flexible flat cable shown in FIG. 4 has a plurality of flat rectangular conductors 102 arranged at equal intervals between two insulating films 101a and 101b. An end portion of the flat conductor 102 has an exposed portion 103 that is exposed to a predetermined length. On one side of the exposed portion 103 (a lower surface in FIG. 4), a relatively rigid plastic reinforcement is provided. A film 105 is provided.

  The flexible flat cable shown in FIG. 5 is a multilayer ground conductor in which a signal flat conductor 202 made of one flat conductor and two flat conductors 204a and 204b are overlapped between two insulating films 201a and 201b. 204 are arranged at equal intervals, both ends of each conductor are exposed over a certain length, and a reinforcing film 205 is attached to one side of each end or one end. Further, the ground flat rectangular conductor 204a to which the reinforcing film 205 is not bonded is folded back from both ends of the insulating film 201 to the insulating film 201 as a folded ground conductor, and an adhesive is applied to the metal foil outer surface 212a of the metal foil laminate film. The applied electromagnetic shield film 212 is disposed so that the metal foil surface 212a and the folded ground conductor 204a are electrically connected with the metal foil surface inside.

However, since the flexible flat cable shown in FIG. 4 does not include a shield layer, there is a possibility that a failure may occur due to electromagnetic waves entering the circuit of the electronic device.
In addition, when the flexible flat cable as shown in FIG. 5 is folded along the two flat conductors 204a on the ground conductor 204, it is difficult to manufacture the two flat conductors 204a without any deviation. Met. Moreover, since the process of laminating | stacking the electromagnetic shielding film 209 is needed after flexible flat cable preparation, the process became complicated and the man-hour was taking extra.

In order to solve the above problems, the flexible flat cable previously proposed by the present inventor is as shown in FIG. The flexible flat cable 301 includes an insulating conductor 305 in which an insulating layer 303 and an adhesive layer 304 are sequentially stacked on the periphery of the long first flat rectangular conductor 302 when viewed from the transverse cross-sectional direction, and a long second flat conductor 301. A grounding conductor 307 made of a flat conductor 306 and an insulating tape 310 formed by bonding a resin tape 308 and a metal tape 309 are provided, and the insulating conductor 305 and the grounding conductor 307 are arranged at predetermined intervals in the width direction. They are arranged side by side and sandwiched and laminated in the thickness direction by an insulating tape 310 with the metal tape 309 inside, and the longitudinal ends of the first rectangular conductor 302 and the second rectangular conductor 306 have a predetermined length. It is exposed to the outside of the insulating tape. In the flexible flat cable 301 having such a configuration, since the insulating tape 310 for laminating the conductors (the ground conductor 307 and the insulated conductor 305) has a shielding property, it is possible to obtain a flexible flat cable having a shielding property with a simple structure. It becomes.
However, since there is a region where the adhesive 304 is applied only on the outer peripheral portion of the insulated conductor 305, the adhesiveness of the flexible flat cable 301 may be slightly inferior.
Japanese Patent Laid-Open No. 5-242736

The present invention has been made in view of the above circumstances, and provides a flexible flat cable that has a simple structure and excellent shielding properties, and also has excellent adhesion strength of an insulating tape for laminating a conductor. One purpose.
The second object of the present invention is to provide a method for producing a flexible flat cable that simplifies the process and improves workability, reduces man-hours and costs, and improves shielding and adhesion. And

  The flexible flat cable according to claim 1 of the present invention is composed of an insulating conductor in which an insulating layer is disposed around a long first flat conductor as viewed from the transverse cross-sectional direction, and a long second flat conductor. A grounding conductor, and an insulating tape in which a resin tape, a metal tape, and a conductive adhesive are sequentially stacked, and the insulating conductor and the grounding conductor are arranged at predetermined intervals in the width direction. And sandwiched from the thickness direction by the insulating tape with the conductive adhesive inside, and the longitudinal ends of the first rectangular conductor and the second rectangular conductor have a predetermined length. It is exposed to the outside of the insulating tape.

  According to a second aspect of the present invention, there is provided a method for producing a flexible flat cable, the step of forming an insulating layer around an elongated first flat rectangular conductor as viewed from the cross-sectional direction to form an insulating conductor, a resin tape and a metal tape A step of forming an insulating tape by sequentially superposing a conductive adhesive and a conductive adhesive, the insulating conductor and a ground conductor made of a long second flat conductor are arranged side by side at a predetermined interval in the width direction, and the insulating conductor And a step of laminating from the thickness direction with the insulating tape with the conductive adhesive inside, leaving a predetermined length of the longitudinal end of the grounding conductor, and the length of the insulating conductor It comprises at least a step of removing a portion of the insulating layer not sandwiched between the insulating tapes at the end of the direction to expose the first rectangular conductor.

The flexible flat cable of the present invention includes an insulating conductor in which an insulating layer is arranged around a long cross section of the first flat conductor, a grounding conductor made of a long second flat conductor, and a resin. An insulating tape in which a tape, a metal tape, and a conductive adhesive are sequentially stacked, and the insulating conductor and the grounding conductor are arranged at predetermined intervals in the width direction, and the conductive adhesive It is sandwiched and laminated from the thickness direction by the insulating tape with the agent on the inside, and the longitudinal ends of the first flat conductor and the second flat conductor have a predetermined length outside the insulating tape. Exposed.
According to this configuration, since the conductors (the ground conductor and the insulating conductor) are arranged in the conductive adhesive between the insulating tapes, the bonding area between the insulating tape and the conductive adhesive and between the conductor and the conductive adhesive Becomes larger and the adhesive strength of the insulating tape is improved. In addition, since the conductive adhesive has flexibility, when the cable is bent, the conductive adhesive is similarly bent, and the conductive adhesive and the insulating tape (metal tape), and It is possible to prevent the insulating tape and the conductive adhesive from being peeled off by bending or the like. Furthermore, the conductive adhesive easily enters the uneven portions of the conductor and the spacing between the conductors, and the conductor and the insulating tape can be securely bonded. Therefore, it is possible to obtain a flexible flat cable that is hardly peeled off against deformation such as bending of the cable and is stable for a long period of time.
Even if the size, shape, and pitch of the conductors are different, the conductive adhesive easily enters the uneven portions of the conductors and the spaces between the conductors to flatten the surface. Even in such a case, it is possible to obtain a flexible flat cable having excellent adhesion and a high degree of design freedom.
In addition, since the adhesive has conductivity, the metal tape bonded to the resin tape and the conductive adhesive are connected to the ground conductor to serve as a shield layer. Therefore, it is possible to obtain a flexible flat cable having a simple configuration and excellent shielding performance.

The method for producing a flexible flat cable of the present invention includes a step of forming an insulating layer around an elongated first flat conductor viewed from the transverse cross-sectional direction to form an insulating conductor, a resin tape, a metal tape, and a conductive adhesive. Forming an insulating tape by sequentially stacking the insulating conductor and a ground conductor made of a long second flat rectangular conductor, arranged side by side at a predetermined interval in the width direction of the insulating conductor and the grounding conductor. Leaving the predetermined length of the end in the longitudinal direction, laminating the insulating adhesive with the conductive adhesive inside, sandwiching from the thickness direction, and in the longitudinal end of the insulated conductor, A step of removing a portion of the insulating layer not sandwiched between insulating tapes to expose the first rectangular conductor.
According to such a configuration, the conductive adhesive is applied to the entire surface of the insulating tape and the conductor is laminated, so that the strength of the insulating tape can be improved and a flexible flat cable having excellent adhesion can be obtained. It becomes possible.
Further, the insulating conductor and the grounding conductor are laminated with an insulating tape having a function of a shield layer. Therefore, it is possible to manufacture the cable and connect the outer shield and the ground conductor in one process, and post-processing (insulation layer incision or conductor in order to align the conductor and to establish conduction between the grounding conductor and the outer shield. Is not necessary.
Thereby, in this invention, while simplifying a process and improving workability | operativity, it becomes possible to manufacture the flexible flat cable excellent in shielding property and adhesiveness, reducing a man-hour and cost.

  Hereinafter, the present invention will be described in detail with reference to the drawings. However, the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

1A and 1B are diagrams schematically showing a first embodiment of a flexible flat cable (FFC) 1 of the present invention. FIG. 1A is a top view and FIG. 1B is a cross-sectional view. An insulating conductor 4 in which an insulating layer 3 is arranged around the long first flat conductor 2 as viewed from the transverse cross-sectional direction, a grounding conductor 6 made of a long second flat conductor 5, and a resin tape 9; And an insulating tape 10 in which a metal tape 8 and a conductive adhesive 7 are sequentially stacked, and the insulating conductor 4 and the grounding conductor 6 are arranged at predetermined intervals in the width direction thereof, and conductive adhesive is provided. It is sandwiched and laminated from the thickness direction by the insulating tape 10 with the agent 7 inside, and the longitudinal ends of the first flat conductor 2 and the second flat conductor 5 have a predetermined length outside the insulating tape 10. It is exposed to.
Each will be described below.

The insulated conductor 4 is formed by arranging an insulating layer 3 around the first flat rectangular conductor 2 as viewed from the cross-sectional direction in the longitudinal direction.
The material of the insulating layer 3 is not particularly limited as long as it has insulating properties, and examples thereof include resins having insulating properties such as enamel, UV resin, and polyethylene resin.

  The grounding conductor 6 is a bare rectangular conductor in which the insulating layer 3 is not processed on the second rectangular conductor 5.

  Examples of the rectangular conductors forming the first rectangular conductor 2 and the second rectangular conductor 5 include those having a thickness of about 0.035 mm and a width of about 0.3 mm made of an annealed copper wire or the like. Further, the size, the number of cores, the pitch, and the like are not particularly limited, and can be appropriately adjusted and used in consideration of the electronic component to be applied.

The insulating tape 10 is formed by joining one surface 8 a of the metal tape 8 and one surface 9 a of the resin tape 9, and the conductive adhesive 7 is laminated on the other surface 8 b side of the metal tape 8.
Although it does not specifically limit as a material of the conductive adhesive 7, For example, what mixed conductive materials, such as a copper filler, with the material which has adhesive effects, such as a hot melt, an adhesive agent, and a solvent, is mentioned. And its thickness is 15-100 μm.
By using a conductive adhesive, the grounding conductor can be electrically connected to the metal tape through the conductive adhesive. Conventionally, the adhesive could not be applied to the entire outer periphery of the grounding conductor, but in the present invention, since the conductive adhesive is used, it can be applied to the entire outer peripheral surface of the grounding conductor 6. Thus, the adhesion of the flexible flat cable 1 can be improved.
Although it does not specifically limit as a material of the metal tape 8, For example, the metal material which has shielding effects, such as copper and aluminum, is mentioned.
The material of the resin tape 9 is not particularly limited, but for example, a thickness of 10 to 10 made of a plastic such as a saturated polyester such as polyethylene terephthalate (PET) or polyethylene naphthalate, polyimide, polyphenylene sulfide, polyethylene, polypropylene, or polyamide. A 200 μm film may be mentioned. Of these, polyethylene terephthalate is preferable from the viewpoint of electrical characteristics, mechanical characteristics, cost, and the like.

In the flexible flat cable 1 of the present invention, a long insulating conductor 4 and a long grounding conductor 6 are arranged side by side at a predetermined interval in the width direction, and sandwiched from the thickness direction by an insulating tape 10. The first flat conductor 2 and the second flat conductor 5 have end portions in the longitudinal direction having a predetermined length exposed to the outside of the insulating tape 10. As a result, the flexible flat cable 1 has a simple configuration and excellent shielding properties.
Further, since the conductive adhesive 7 is disposed so as to cover the insulating conductor 4 and the ground conductor 6 and is applied to the entire surface of the insulating tape 10 that laminates the insulating conductor 4 and the ground conductor 6, The conductors (insulated conductor 4 and ground conductor 6) are more firmly bonded, and the bonding strength can be improved. Therefore, the adhesiveness of the flexible flat cable 1 is improved, and the flexible flat cable 1 that can be used stably over a long period of time can be obtained without causing separation or the like with respect to deformation such as bending of the cable.
Further, even if the conductor (the first flat conductor 2 and / or the second flat conductor 5) is different in size, shape, and pitch, the conductive adhesive 7 can be easily applied to the concave and convex portions of the conductor and the spaces between the conductors. Since the surface enters and is flattened, it is possible to obtain a flexible flat cable 1 having excellent adhesion even when such a conductor is provided and having a high degree of design freedom.

FIG. 2 is a process diagram schematically showing the method for manufacturing the flexible flat cable 1 of the present invention.
The method for producing a flexible flat cable according to the present invention includes the step of forming the insulating layer 3 around the long first flat rectangular conductor 2 as viewed from the cross-sectional direction to form the insulating conductor 4, the metal tape 8 and the resin tape 9. A step of bonding the insulating tape 10, a step of applying the conductive adhesive 7 to the metal tape 8 side of the insulating tape 10, an insulating conductor 4 and a ground conductor 6 composed of a long second rectangular conductor 5, The side of the insulating tape 10 on which the conductive adhesive 7 is formed is defined as the inner side with the predetermined lengths of the longitudinal ends of the insulating conductor 4 and the grounding conductor 6 being arranged at predetermined intervals in the width direction. The step of laminating with the insulating tape 10 from the thickness direction and the insulating layer 3 in the longitudinal direction end portion of the insulating conductor 4 are removed to remove the insulating layer 3 that is not sandwiched by the insulating tape 4. A step of exposing Wherein at least provided.
Hereinafter, each step will be described.

First, as shown in FIG. 2A, the insulating conductor 4 is formed by forming the insulating layer 3 around the long first flat rectangular conductor 2 as viewed from the cross-sectional direction.
The method for forming the insulating layer 3 is not particularly limited, but a coating method by extrusion coating is desirable because of its high efficiency.

  2B, the one surface 9a of the resin tape 9 and the one surface 8a of the metal tape 8 are bonded together to form the insulating tape 10. The resin tape 9 and the metal tape 8 can be bonded together, for example, by heating and pressure bonding.

  Next, as shown in FIG. 2C, the conductive adhesive 7 is applied to the other surface 8b of the metal tape 8 by, for example, a spin coating method.

Next, as shown in FIG. 2 (d), the insulated conductor 4 and the grounding conductor 6 made of the long second flat rectangular conductor 5 are arranged at predetermined intervals in the width direction, and the insulated conductor 4 and The grounding conductor 6 is laminated by being sandwiched from the thickness direction by the insulating tape 10 with the metal tape 8 coated with the conductive adhesive 7 inside, leaving a predetermined length at the end in the longitudinal direction.
As the grounding conductor 6, a bare flat conductor (second flat conductor 5) that is not processed is prepared and used.

Next, as shown in FIGS. 2 (e) and 2 (f), the insulating layer 3 in a portion not sandwiched between the insulating tapes 10 is removed from the longitudinal ends of the insulating conductor 4, and the first rectangular conductor 2 is Expose.
2 (e) and 2 (f) are enlarged perspective views showing a part surrounded by a dotted line α in FIG. 1 (a).
The insulating layer 3 can be removed by, for example, manual work.
Thereby, the flexible flat cable 1 as shown in FIG. 1 is produced.

In the method for manufacturing the flexible flat cable 1 of the present invention, the conductive tape 7 is applied to the entire surface 8b of the insulating tape 10 and the conductors (the insulating conductor 4 and the ground conductor 6) are laminated. The attachment strength can be improved, and the flexible flat cable 1 having excellent adhesion can be obtained. In particular, since the conductive adhesive 7 easily enters and adheres to the concavo-convex portions of the conductors (the insulated conductor 4 and the ground conductor 6), even if the size, shape, pitch, etc. of the conductor are different, the adhesion is impaired. The flexible flat cable 1 can be produced without any problems.
Further, the insulating conductor 4 and the grounding conductor 6 are sandwiched and laminated by an insulating tape 10 having a function of a shield layer. Therefore, it is possible to fabricate the flexible flat cable and laminate the outer shield in one step. Conventionally, post-processing to obtain the conductor alignment and conduction between the grounding conductor and the outer shield, which are necessary steps ( Insulating layer incision, conductor folding, etc.) become unnecessary.
Thereby, in this invention, while simplifying a process and improving workability | operativity, it becomes possible to manufacture the flexible flat cable 1 excellent in shielding property and adhesiveness, reducing a man-hour and cost.

  FIG. 3 is a diagram schematically showing a second embodiment of the flexible flat cable of the present invention. 3A is a perspective view, and FIG. 3B is an LL cross-sectional view in FIG. An insulating conductor 224 in which an insulating layer 23 is arranged around the long first flat rectangular conductor 22 as viewed from the cross-sectional direction, a grounding conductor 26 including a long second flat conductor 25, And an insulating tape 30 in which a metal tape 28 and a conductive adhesive 27 are sequentially stacked, and an insulating conductor 24 and a grounding conductor 26 are arranged side by side at a predetermined interval in the width direction, and conductive adhesive The longitudinal ends of the first flat conductor 22 and the second flat conductor 25 have a predetermined length at the outside of the insulating tape 30. It is exposed to. A reinforcing plate 35 that reinforces the insulating conductor 24 and the grounding conductor 26 is disposed on the other surface 29 b side of the resin tape 29.

  The insulating conductor 24, the grounding conductor 26, the insulating tape 30, and the conductive adhesive 27 are the same as in the first embodiment.

  The reinforcing plate 35 is disposed on the other surface 29 b of the resin tape 29 and reinforces the insulating conductor 24 and the grounding conductor 26. The reinforcing plate 35 is made of relatively rigid plastic, and examples thereof include polyester. By providing the reinforcing plate 35, when the flexible flat cable 21 is connected to a terminal or the like, the connection portion can be stabilized and poor conduction can be suppressed. Further, the reinforcing plate 35 serves as a guide for the flexible flat cable 21 and can be easily inserted and removed.

  The manufacturing method of the flexible flat cable which concerns on 2nd Embodiment of this invention can be performed similarly to 1st Embodiment. As in the first embodiment, after laminating the insulating conductor 24 and the grounding conductor 26 with an insulating tape, the reinforcing plate 35 is bonded to the other surface 29b of the resin tape 29 to obtain the flexible flat cable of the second embodiment. Can do.

The flexible flat cable of the present invention was evaluated as Experimental Example 1, and the simple structure, shielding properties, and adhesion were evaluated.
Also, the flexible flat cable shown in FIG. 4 (a) is experimental example 2, the flexible flat cable shown in FIG. 5 (a) is experimental example 3, and the invention previously proposed by the present inventor shown in FIG. A flexible flat cable was set as Experimental Example 4, and the simple structure, shielding properties, and adhesion were evaluated in the same manner as in Experimental Example 1. The results are shown in Table 1.
In addition, regarding the simplicity of the structure, in the production of a flexible flat cable, the case where the shield layer can be laminated in one step is indicated as ○, and the case where two or more steps are required is indicated as ×.
The shielding property was examined by the near magnetic field probe method, and indicated as ◯ when the shielding property was sufficient, Δ when the shielding property was weak, and × when the shielding property was not.
Regarding adhesion, a peel strength test was performed, and a case where the adhesion was sufficient was indicated as ◯, slightly weak, but a case where the adhesion was sufficient was indicated as Δ, and a case where the adhesion was weak was indicated as x.

From the results of Table 1, it was observed that the flexible flat cable of Experimental Example 2 shown in FIG. 4 has a simple structure and sufficient adhesion, but has no shielding layer. Not observed.
In the flexible flat cable of Experimental Example 3 shown in FIG. 5, sufficient adhesion was observed, but since the electrical connection between the grounding conductor and the shield layer is made by contact, the shielding performance is improved in connection reliability. A slight chipping was observed. Moreover, it was necessary to arrange a shield tape on the outer periphery of the tape laminated with the conductor, and the structure was complicated.
In the flexible flat cable of Experimental Example 3 shown in FIG. 6, since the laminate tape (insulating tape) has the function of a shield layer, the shield layer can be formed at the same time when the conductor is sandwiched between the laminate tapes. Accordingly, it was observed that the shield layer has a sufficient structure because it has a simple structure and the shield layer is disposed on the entire outer surface of the ground conductor. However, since the adhesive was disposed only around the insulated conductor, a slight decrease in adhesion was observed.
On the other hand, in Experimental Example 1 which is the flexible flat cable of the present invention, since the laminate tape (insulating tape) has the function of a shield layer as in Experimental Example 4, the conductor is sandwiched between the laminated tapes using a conductive adhesive. At the same time, the shield layer can be formed simultaneously. Accordingly, it was observed that the shield layer has a sufficient structure because it has a simple structure and the shield layer is disposed on the entire outer surface of the ground conductor. Further, since the adhesive (conductive adhesive) was applied to the entire surface to which the insulating tape was bonded, the adhesive strength of the laminate tape was increased and sufficient adhesion was observed.
From the above, it was confirmed that the present invention is a flexible flat cable having a simple structure and excellent shielding properties and adhesion.

  The present invention is widely applicable to flexible flat cables.

It is a schematic diagram which shows an example of the flexible flat cable which concerns on 1st Embodiment of this invention. It is sectional process drawing which shows typically the manufacturing process of the flexible flat cable which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows an example of the flexible flat cable which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows an example of the conventional flexible flat cable. It is a schematic diagram which shows another example of the conventional flexible flat cable. It is a schematic diagram which shows another example of the conventional flexible flat cable.

Explanation of symbols

  1,21 Flexible flat cable, 2,22 First flat conductor, 3,23 Insulating layer, 4,24 Insulated conductor, 5,25 Second flat conductor, 6,26 Grounding conductor, 7, 27 Conductive adhesive, 8,28 Metal tape, 9,29 Resin tape, 10,30 Insulating tape, 35 Reinforcing plate, 101 (101a, 101b) Insulating film, 102 Flat conductor, 105 Reinforcing film, 201 (201a, 201b) Insulating film, 202 Signal flat conductor, 204 (204a, 204b) Ground conductor, 212 Electromagnetic shield film.

Claims (2)

Insulating conductor with an insulating layer arranged around the cross section of the long first flat conductor, grounding conductor made of a long second flat conductor, resin tape, metal tape, conductive Insulating tape with a stack of adhesive adhesives in order,
The insulated conductor and the grounding conductor are arranged at predetermined intervals in the width direction, and are sandwiched and laminated from the thickness direction by the insulating tape with the conductive adhesive inside, the first conductor The flexible flat cable is characterized in that a predetermined length is exposed to the outside of the insulating tape at the longitudinal ends of the flat conductor and the second flat conductor. A step of forming an insulating layer around the long flat first rectangular conductor as viewed from the cross-sectional direction to form an insulated conductor;
A process of forming an insulating tape by sequentially stacking a resin tape, a metal tape, and a conductive adhesive;
The insulated conductor and a ground conductor composed of a long second rectangular conductor are arranged at predetermined intervals in the width direction, leaving a predetermined length at the longitudinal ends of the insulated conductor and the grounding conductor. And laminating from the thickness direction by the insulating tape with the conductive adhesive inside, and
A method for producing a flexible flat cable, comprising: at least a step of removing a portion of the insulating layer that is not sandwiched between the insulating tapes to expose the first flat conductor at a longitudinal end portion of the insulating conductor. .

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