JP2004259619A - Flexible flat cable sheathed with shield material and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible flat cable (FFC) sheathed with a shield material and a manufacturing method thereof achieving high reliability of connection between the shield material and a ground conductor. <P>SOLUTION: A plurality of flat-square conductors 4 are arranged in parallel with each other to form a conductor group. An insulating film 2c having an insulating adhesive layer 2b is bonded to each of top and bottom surfaces of the conductor group with the adhesive layer 2b facing inward, and they are integrated to form the FFC 2. The FFC 2 is formed such that the insulating film 2c is partially removed to thereby expose the ground conductor 3 from the surface of the FFC 2, and the FFC 2 and the shield material 1 are bonded to each other. Then, a metal plate 6 is placed on the shield material 1, and the exposed portion of the ground conductor 3 formed at the surface of the FFC 2 is electrically connected to a shield metal 1b of the shield material 1 and the metal plate 6 by ultrasonic bonding. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

この結果、加圧力は２．０〜３．０ｋｇｆ、印加エネルギーは５．０〜１０．０Ｊが最良であった。
【００２５】
次に、本発明のシールド材被覆ＦＦＣと図４〜図６に示した従来のシールド材被覆ＦＦＣについて、熱衝撃試験を行う前と行った後の２０℃におけるアース間抵抗を測定した結果を表２に示す。熱衝撃試験は、−４０℃の状態を３０分保持した後、１００℃の状態を３０分保持して、これを１サイクルとし、１００サイクルと１０００サイクル繰り返した試験を行った。
【００２６】
【表２】

表２に示されているように、従来例では、熱衝撃試験による環境試験を行った際、アース間抵抗が上昇してしまうが、本実施例では、初期値と全く変わらず、優れた品質であることが分る。
【００２７】
【発明の効果】
以上の要するに、本発明によれば、ＦＦＣの接地導体とシールド材のシールド金属の電気的接続信頼性の高いシールド材被覆ＦＦＣを提供することができる。
【図面の簡単な説明】
【図１】本発明のシールド材被覆ＦＦＣの平面図である。
【図２】本発明のシールド材被覆ＦＦＣの図１におけるＣ−Ｃ部の横断面図である。
【図３】本発明のシールド材被覆ＦＦＣの製造方法において超音波接合を行っている状態におけるシールド材被覆ＦＦＣの縦断面図である。
【図４】従来のシールド材被覆ＦＦＣの平面図である。
【図５】従来のシールド材被覆ＦＦＣの図４におけるＡ−Ａ部の横断面図である。
【図６】従来のシールド材被覆ＦＦＣの図４におけるＢ−Ｂ部の横断面図である。
【符号の説明】
１、１１ シールド材
１ａ、１１ａ 絶縁性プラスチックフィルム
１ｂ、１１ｂ シールド金属
１ｃ、１１ｃ 接着剤層
２、１２ ＦＦＣ
２ａ、１２ａ 絶縁性プラスチックフィルム
２ｂ、１２ｂ 接着剤層
２ｃ、１２ｃ 絶縁膜
３、１３ 接地導体
４、１４ 導体
５、１５ 窓（穴）
６ 金属板
７ 超音波ホーンチップ
８ 超音波ホーン
９ アンビル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flexible flat cable used for automobile equipment and the like, and more particularly to a shielded material-covered flexible flat cable in which both sides of a flexible flat cable are covered with a shielding material, and a method of manufacturing the same.
[0002]
[Prior art]
A conventional shielded material-covered flexible flat cable and its manufacturing method will be described with reference to FIGS.
FIG. 4 is a plan view of a conventional flexible flat cable covered with a shield material, FIG. 5 is a cross-sectional view taken along a line AA in FIG. 4, and FIG. 6 is a cross-sectional view taken along a line BB in FIG. First, the flexible flat cable (hereinafter, referred to as FFC) 12 before covering with the shielding material 11 will be described. The FFC 12 is a tape-shaped electric wire, and a thickness of about 0.3 mm or less is generally used.
[0003]
As a method for manufacturing the FFC 12, a method is generally used in which an insulating film 12c having an adhesive layer 12b is bonded to both surfaces of a conductor group in which one to several tens of conductors 14 are arranged in parallel and thermocompression-bonded. It is a target. The insulating film 12c is obtained by providing an insulating adhesive 12b on one surface of an insulating plastic film 12a.
The FFC 12 is used for various electric wirings. In particular, in AV devices such as VTRs, CDs, and DVD players, OA and personal computer peripheral devices such as copiers, scanners, and printers, and other electronic and electric devices, From the viewpoint of preventing noise, a shield material-covered FFC in which the shield material 11 is bonded to both surfaces of the FFC 12 is often used.
In general, the shielding material 11 is an insulating plastic 11a such as PET having a thickness of several μm to several tens of μm serving as a base material and a middle layer of Cu or Al having a thickness of several μm or less. And a conductive adhesive layer 11c having a thickness of several tens μm as an innermost layer.
[0004]
In the FFC 12, the insulating film 12c is partially stripped so that the conductor 14 is exposed on the surface thereof (in FIG. 6, the upper surface or the lower surface in FIG. 6), and the exposed conductor (the conductor Is electrically connected between the exposed portion of the ground conductor 13 shown in FIG. 6) and the shield member 11 so that a shielding effect can be obtained. Reference numeral 15 denotes a window (hole) formed on the surface of the FFC 12 by partially stripping the insulating film 12c.
Since the FFC 12 has excellent bending resistance, it is often used for wiring of a movable portion (bent portion) of an electric / electric device circuit. The shielding material-covered FFC is also used for the movable portion (bent portion) wiring for the same reason.
[0005]
As a method of manufacturing the above-mentioned conventional shield material-coated FFC, Japanese Patent Application No. 2002-186221, which is an unpublished prior application, discloses a method in which a plurality of rectangular conductors are arranged in parallel to form a conductor group. An insulating film having an insulating adhesive layer is bonded to the upper and lower surfaces with the adhesive layer inside, and integrated to form an FFC, and a shielding material having a conductive adhesive layer is bonded to the upper and lower surfaces of the FFC. It also describes manufacturing a shield material-coated FFC.
[0006]
[Problems to be solved by the invention]
In the case of the conventional shield material-coated FFC, the ground conductor 13 and the shield metal 11b of the shield material 11 are electrically connected to each other via the conductive adhesive 11c. When an environmental test is performed, the physical properties of the conductive adhesive 11c are changed, and the initial shielding performance is reduced, resulting in a problem that connection reliability is deteriorated.
[0007]
An object of the present invention is to solve the above problems and provide a highly reliable shield material-coated FFC and a method of manufacturing the same with respect to the connection between the shield material and the ground conductor.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a conductor group formed by arranging a plurality of conductors in parallel and forming an insulating film having an insulating adhesive layer on each of the upper and lower surfaces of the conductor group with an adhesive. A method of manufacturing a shield material-covered FFC by bonding together with the layers inside and forming an FFC, and bonding a shield material having a shield metal to the upper and lower surfaces of the flat cable, wherein the FFC comprises the insulating film Is formed so that the conductor is exposed from one side or both sides of the FFC and partially removed, and after bonding the FFC and the shielding material, the conductor formed on one side or both sides of the FFC An object of the present invention is to electrically connect the exposed portion and the shield metal of the shield material by using ultrasonic bonding.
[0009]
A metal plate may be placed on the shield material, and ultrasonic bonding may be performed from above, and the exposed portion of the conductor, the shield metal, and the metal plate may be metal-bonded. For example, at the time of ultrasonic bonding, a metal plate is inserted between a shield material and a horn chip to which ultrasonic waves are applied, and the shield material and the conductor are connected together with the metal plate. The material of the metal plate is preferably the same as the material of the FFC conductor. This is because the same material is easier to join, and it is not necessary to apply extra energy to the shielding material-coated FFC.
[0010]
After performing the ultrasonic bonding, the metal plate and the connection portion may be covered with an insulating film.
By ultrasonic bonding according to the above-described manufacturing method of the present invention, even when an adhesive layer is provided on the surface of the shield material facing the FFC, the adhesive layer is removed and the shield metal of the shield material is removed. The conductor of the FFC can be metal-joined and directly electrically connected.
[0011]
In addition, in order to remove the adhesive or to sufficiently metal-join the shield metal of the shield material and the conductor of the FFC, it is necessary to apply ultrasonic energy in accordance with the energy. There is a possibility that the shield metal may be partially broken and the connection reliability may be reduced, but by sandwiching the metal plate on the shield material and connecting the shield metal of the shield material and the FFC conductor together with the metal plate, This can be solved. According to the ultrasonic bonding using the metal plate, the shield metal of the shield material and the conductor are metal-bonded, and the metal plate is also metal-bonded immediately adjacent to the shield metal, so that the protection between the shield metal and the conductor is protected, Connection reliability can be improved.
[0012]
Further, according to the present invention, an FFC is formed by bonding an insulating film having an insulating adhesive layer to the upper and lower surfaces of a conductor group in which a plurality of conductors are arranged in parallel with the adhesive layer inside. In a shield material-covered FFC formed by bonding a shield material having a shield metal on the upper and lower surfaces of the FFC, the conductor and the shield metal are directly electrically connected on the surface of the FFC. is there.
[0013]
It is preferable that the conductor and the shield metal are electrically connected by metal bonding.
It is preferable that a metal plate is provided on the connection portion between the conductor and the shield metal, and the conductor, the shield metal, and the metal plate are electrically connected by metal bonding.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a plan view of a shield material-coated FFC of the present invention, FIG. 2 is a cross-sectional view of a portion C-C in FIG. 1, and FIG. It is a longitudinal section of shield material covering FFC in the state where ultrasonic bonding is performed.
[0015]
A conductor group is formed by arranging a plurality of rectangular conductors 4 made of copper having a thickness of 127 μm in parallel, and an insulating film 2c having an insulating adhesive layer 2b is bonded to the upper and lower surfaces of the conductor group. The FFC 2 is formed by laminating and integrating with the agent layer 2b inside. The insulating film 12c is obtained by providing an insulating plastic film 12a made of PET having a thickness of 50 μm and an insulating adhesive 12b made of a flame-retardant polyester-based adhesive having a thickness of 42 μm on one surface. Thereafter, the shield material 1 having the shield metal 1b is attached to the upper and lower surfaces of the FFC 2 to manufacture a shield material-coated FFC. In the shielding material 1, a shielding metal 1b made of aluminum having a thickness of 7 μm is sandwiched between an insulating plastic film 1a made of PET having a thickness of 9 μm and an adhesive layer 1c made of a flame-retardant polyester adhesive having a thickness of 30 μm. It has a three-layer structure, and the adhesive layer 1c is provided on the side facing the FFC 2.
[0016]
In the FFC 2, the grounding conductor 3 (of the plurality of conductors 4) is formed on one side (in FIG. 2, the upper or lower side of the drawing) or both sides of the FFC 2 with the insulating film 2 c partially removed. After the FFC 2 and the shield member 1 are bonded together, the exposed portion of the ground conductor 3 formed on one or both sides of the FFC 2 and the shield metal 1b of the shield member 1 are formed. Are electrically connected using ultrasonic bonding. Reference numeral 5 denotes a window (hole) formed on the surface of the FFC 2 by partially removing the insulating film 12c.
[0017]
When performing ultrasonic bonding, a metal plate 6 is placed on the shield material 1 as shown in FIGS. 2 and 3, and ultrasonic bonding is performed from above, and the exposed portion of the ground conductor 3, the shield metal 1b and the metal Preferably, the plate 6 is metal bonded.
Although not shown, if the metal plate 6 and the connection portion are covered with an insulating film after performing the ultrasonic bonding, electrical contact with the outside of the metal plate 6 can be prevented.
[0018]
The ground conductor 3 and the shield metal 1b are directly electrically connected on the surface of the FFC 2, and the connection portion has a structure in which nothing is interposed between the shield metal 1b and the ground conductor 3. I have.
Since the metal plate 6 is provided on the connection between the ground conductor 3 and the shield metal 1b, and the conductor 3, the shield metal 1b and the metal plate 6 are electrically connected by metal bonding, the reliability of the electrical connection is improved. Is very high.
[0019]
The thickness of the metal plate is preferably 10 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less. The optimum thickness is 30 μm or more and 60 μm or less. The reason for this is that if the metal plate is too thin, the metal plate itself will break or become unusable because of the high price.If the metal plate is too thick, the energy for applying ultrasonic waves will increase, This is because there is a problem that the possibility that the shield metal is broken is increased, and the connection reliability of the connection portion is reduced.
[0020]
Further, the adhesive layer 1c of the shield material 1 may be non-conductive or conductive. The metal plate 6 is preferably made of the same material as the ground conductor 3, but is not limited as long as it is a metal (for example, copper alloy) that can be joined to the ground conductor 3. The ultrasonic frequency of the ultrasonic welding machine is 20 kHz, 40 kHz, 60 kHz, or the like, and the pitch interval, shape, and the like of the horn tip and the anvil can be appropriately changed.
[0021]
【Example】
In the shielded material-covered FFC having the above-described configuration, a metal plate 6 made of a 32 μm copper plate is placed on the shield material 1, and a 40 kHz ultrasonic wave is applied from above the flat plate-shaped ground conductor 3 and the shield metal 1b. An experiment of ultrasonic bonding was performed. When applying the ultrasonic waves, the energy was changed, and the pressing force for pressing the metal plate 6 by the ultrasonic horn tip 7 was changed, and nine types of experiments were performed. The conditions of the experiment are as follows.
[0022]
(1) Metal plate: copper 32 μm
(2) Ultrasonic welding machine: 40 kHz
(3) Ultrasonic horn tip shape: 0.3 x 0.3 mm pitch (4) Anvil shape: 0.3 x 0.3 mm pitch (5) Pressure: 1 to 5 kgf
(6) Applied energy: 5.0 to 15.0 J
[0023]
In addition, the weldability was evaluated based on the following items (a) to (c). Table 1 shows the results.
(A) Appearance (break of shield)
(B) Ground resistance (c) Peel strength (peel strength)
[0024]
[Table 1]

As a result, the best pressure was 2.0 to 3.0 kgf and the applied energy was 5.0 to 10.0 J.
[0025]
Next, with respect to the shield material-coated FFC of the present invention and the conventional shield material-coated FFC shown in FIGS. 4 to 6, the results of measuring the resistance between the earth at 20 ° C. before and after performing the thermal shock test are shown. It is shown in FIG. In the thermal shock test, a test in which a state of −40 ° C. was maintained for 30 minutes, a state of 100 ° C. was maintained for 30 minutes, and this was regarded as one cycle was repeated 100 cycles and 1000 cycles.
[0026]
[Table 2]

As shown in Table 2, in the conventional example, when an environmental test by a thermal shock test was performed, the resistance between the grounds increased. It turns out that it is.
[0027]
【The invention's effect】
In summary, according to the present invention, it is possible to provide a shield material-coated FFC with high electrical connection reliability between the ground conductor of the FFC and the shield metal of the shield material.
[Brief description of the drawings]
FIG. 1 is a plan view of a shield material-coated FFC of the present invention.
FIG. 2 is a cross-sectional view of a portion C-C in FIG. 1 of the shield material-coated FFC of the present invention.
FIG. 3 is a longitudinal sectional view of the shield material-coated FFC in a state where ultrasonic bonding is performed in the method of manufacturing a shield material-coated FFC of the present invention.
FIG. 4 is a plan view of a conventional shield material-coated FFC.
FIG. 5 is a cross-sectional view taken along the line AA in FIG. 4 of the conventional shield material-coated FFC.
FIG. 6 is a cross-sectional view of a conventional shield material-coated FFC taken along a line BB in FIG. 4;
[Explanation of symbols]
1, 11 Shielding material 1a, 11a Insulating plastic film 1b, 11b Shielding metal 1c, 11c Adhesive layer 2, 12 FFC
2a, 12a Insulating plastic film 2b, 12b Adhesive layer 2c, 12c Insulating film 3, 13 Grounding conductor 4, 14 Conductor 5, 15 Window (hole)
6 Metal plate 7 Ultrasonic horn tip 8 Ultrasonic horn 9 Anvil

Claims (6)

A conductor group is formed by arranging a plurality of conductors in parallel, and an insulating film having an insulating adhesive layer is attached to each of the upper and lower surfaces of the conductor group with the adhesive layer inside and integrated and flexible. Forming a flat cable, in a method of manufacturing a shielded material-covered flexible flat cable by bonding a shielding material having a shielding metal to the upper and lower surfaces of the flexible flat cable,
The flexible flat cable is formed so that the insulating film is partially removed and the conductor is exposed from one or both surfaces of the flexible flat cable, and the flexible flat cable and the shield material are bonded. A method of manufacturing a shielded material-covered flexible flat cable, wherein an exposed portion of the conductor formed on one or both surfaces of the flexible flat cable is electrically connected to a shield metal of the shield material by using ultrasonic bonding. . The shield material coating according to claim 1, wherein a metal plate is placed on the shield material, and ultrasonic bonding is performed from above, and the exposed portion of the conductor, the shield metal, and the metal plate are metal-bonded. Manufacturing method of flexible flat cable. 3. The method according to claim 1, wherein after the ultrasonic bonding is performed, the metal plate and the connection portion are covered with an insulating film. An insulating film having an insulating adhesive layer is attached to each of the upper and lower surfaces of the conductor group in which a plurality of conductors are arranged in parallel with the adhesive layer inside, to form a flexible flat cable. In a shielding material-covered flexible flat cable formed by bonding a shielding material having a shielding metal on the upper and lower surfaces of the cable,
A flexible flat cable covered with a shield material, wherein the conductor and the shield metal are directly electrically connected on a surface of the flexible flat cable. The flexible flat cable covered with a shield material according to claim 4, wherein the conductor and the shield metal are electrically connected by metal bonding. The metal plate is provided on the connection portion between the conductor and the shield metal, and the conductor, the shield metal, and the metal plate are electrically connected by metal bonding. A flexible flat cable covered with a shield material according to claim 5.

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