JP4158381B2

JP4158381B2 - Terminal connection part of ultra fine multi-core cable and terminal connection method thereof

Info

Publication number: JP4158381B2
Application number: JP2002007512A
Authority: JP
Inventors: 哲間野; 量松井; 仁志上野; 勇揮山本
Original assignee: Hitachi Cable Ltd
Current assignee: Hitachi Cable Ltd
Priority date: 2002-01-16
Filing date: 2002-01-16
Publication date: 2008-10-01
Anticipated expiration: 2022-01-16
Also published as: JP2003208937A

Description

【０００１】
【発明の属する技術分野】
本発明は、極細多芯ケーブルの端末接続部及びその端末接続方法に関する。
【０００２】
【従来の技術】
従来は、極細多芯ケーブルの端末から取り出された複数本の極細線心を導体回路パターンが形成された基板に接続するには、複数本の極細線心の端末部をそれぞれ段剥ぎして導体線を露出させ、その露出した導体線の端末を、導体回路パターン上にそれぞれ半田付けしていた。
【０００３】
図１１は従来の細多芯ケーブルの端末接続方法を示す説明図である。
【０００４】
極細同軸線心を複数本束ねた極細多芯ケーブルの端末部をプリント基板の信号導体回路パターンに接続する場合は、図１１に示すように、極細多芯ケーブル（図示せず。）の端末から複数の極細同軸線心１を取り出し、それぞれの端末部１ａを段剥ぎして、ジャケット層２から中心導体３、絶縁層４及び外部導体層５を露出させ、その中心導体３をプリント基板６の信号導体回路パターン部７に半田接続し、外部導体層５をプリント基板６のグランド導体回路パターン部８に半田接続していた。
【０００５】
【発明が解決しようとする課題】
ところで、近年の電気・電子機器の小型化、高性能化に伴い、これらの機器に用いられる極細多芯ケーブルもさらなる細径化、多芯化が望まれており、極細同軸線心にあっては、現在では外径が０．２ｍｍ以下のものまで開発中である。
【０００６】
また、極細多芯ケーブルの端末部と、表面に導体回路パターンを有する回路パターン部材との接続部である極細多芯ケーブルの端末接続部についても小型化が進んでいる。
【０００７】
しかしながら、接続すべき極細線心の径が細くなり、かつ各極細線心間のピッチを狭ピッチで接続しなければならない状況の中、図１１に示した従来の接続方法は、極細線心を１本ずつ半田接続するため、端末接続部の製造作業に非常に手間がかかり、作業工数が増加し、大幅なコストアップにつながっていたという問題があった。
【０００８】
そこで、本発明の目的は、上記課題を解決し、線心が極細でも狭ピッチ接続が容易な極細多芯ケーブルの端末接続部及びその端末接続方法を提供することにある。
【０００９】
【課題を解決するための手段】
上記目的を達成するために本発明の極細多芯ケーブルの端末接続部は、導体線に絶縁被覆が施された複数の極細線心を束ねた極細多芯ケーブルの上記導体線の端末部と、プリント基板に形成された導体回路パターンとがそれぞれ接続された極細多芯ケーブルの端末接続部において、上記極細線心の端末部を所定のピッチで配列するための複数の溝が形成された基台と、該基台の各溝内に収容された各極細線心の端末部を各溝の上から押さえる線心押さえ部材とを有し、上記導体線の端面は上記基台の端面と同一面となるように形成され、上記基台の上記極細線心が露出した端面に接合され、厚さ方向にのみ導電性を有する異方性導電膜と、該異方性導電膜に接合され、導体回路パターンが上記極細線心の各導体線と重ね合わさるように絶縁性基板上に形成されたプリント基板とを備え、上記基台と上記プリント基板との接合面を上記基台の底面に対して傾斜させたものである。
【００１０】
上記構成に加え本発明の極細多芯ケーブルの端末接続部の極細線心は、中心導体と、中心導体の外周に被覆された絶縁体層と、絶縁体層の外周に施された外部導体層と、外部導体層の外周に被覆されたジャケット層とを有する極細同軸線心であり、かつプリント基板の導体回路パターンは、複数の信号導体回路パターン部と、各信号導体回路パターン部の一端の周囲を取り囲むように形成され外部導体層と接続されるグランド導体回路パターン部とを有してもよい。
【００１１】
上記構成に加え本発明の極細多芯ケーブルの端末接続部の極細線心は外径が０．５ｍｍ以下であり、基台の溝のピッチが０．３ｍｍ〜０．７ｍｍの範囲内にあるのが好ましい。
【００１２】
上記構成に加え本発明の極細多芯ケーブルの端末接続部は、信号導体回路パターン部の他端のピッチが一端のピッチよりも狭く形成されていてもよい。
【００１３】
本発明の極細多芯ケーブルの端末接続方法は、導体線に絶縁被覆が施された極細線心を複数本束ねた極細多芯ケーブルの上記導体線の端末部と、プリント基板上に形成された導体回路パターンとをそれぞれ接続する極細多芯ケーブルの端末接続方法において、上記極細線心の端末部を所定のピッチで形成された基台の溝内に配列し、各溝内に配列された極細線心の端面側となる基台の端面と各導体線の端面とが同一平面となると共に、上記基台と上記プリント基板との接合面が上記基台の底面に対して傾斜するように上記基台の端面を研磨し、上記導体回路パターンの信号導体回路パターン部の一端が上記溝と同一ピッチで形成されたプリント基板を、上記極細同軸線心の端面と上記信号導体回路パターン部の一端とが重ね合わされるように、厚さ方向にのみ導線性を有する異方性導電膜を挟んで上記基台の端面に接合させる方法である。
【００１４】
本発明によれば、極細多芯ケーブルの極細線心が露出した基台の端面に異方性導電膜を挟んでプリント基板を接合することにより、プリント基板の導体回路パターンと極細多芯ケーブルの導体線とが重ね合わされた部分にのみ異方性導電膜内に通電部が形成されるので、極細の線心でも狭ピッチ接続が容易となる。
【００１５】
【発明の実施の形態】
以下、本発明の実施の形態を添付図面に基づいて詳述する。
【００１６】
図１は本発明の前提技術である極細多芯ケーブルの端末接続部の一実施の形態を示す外観斜視図であり、図２は図１のＩＩ−ＩＩ線断面図であり、図３は図１に示した極細多芯ケーブルの極細同軸線心の断面図である。なお、本実施の形態では極細線心として極細同軸線心の場合について述べる。
【００１７】
図３に示す極細同軸線心１０は、単心からなる中心導体１１と、この中心導体１１の外周に設けられた絶縁体層１２と、絶縁体層１２の外周に巻き付けられた複数（図では２０本であるが限定されない。）の外部導体層１３と、外部導体層１３の外周に設けられたジャケット線１４とで構成されている。極細同軸線心１０の外径Ｄは例えば０．２ｍｍである。
【００１８】
図１に示す端末接続部２０は、極細同軸線心１０の端末部を所定のピッチＰ１で配列するための複数の溝２１が形成された基台２２と、基台２２の各溝２１内に収容された各極細同軸線心１０の端末部を各溝２１の上から押さえる線心押さえ板２３とを有し、各極細同軸線心１０の端面は基台２２の一方の端面（図では右側端面）と同一面となるように形成され、基台２２の各極細同軸線心１０の端面が露出した端面に接合され、厚さ方向にのみ導電性を有する異方性導電膜２４と、異方性導電膜２４に接合され、各信号導体回路パターン部２５の一端が極細同軸線心１０の各中心導体と重ね合わさるように絶縁性基板２６上に形成されたプリント基板２７とで構成されている。
【００１９】
図２に示すように線心押さえ板２３は、凹凸断面形状を有しており、各凸部２３ａは基台２２の各溝２１にそれぞれ嵌合することができ、各溝２１内に収容された極細同軸線心１０が所定の位置に所定のピッチＰ１で配置固定されるようになっている。
【００２０】
図４は図１に示す端末接続部に用いられるプリント基板である。
【００２１】
同図に示すプリント基板２７は、フレキシブルな絶縁性基板（例えばポリイミドフィルム）２６の表面に、銅等の導電性金属からなる導体回路パターン２８が形成されたものである。導体回路パターン２８は、一端（図では左側）が極細同軸線心１０の中心導体１１とそれぞれ接続される複数（図では３本であるが限定されない。）の信号導体回路パターン部２５と、極細同軸線心１０の外部導体層１３と接続され、信号導体回路パターン部２５の一端の周囲を取り囲む１本（２本以上であってもよい。）の線状のグランド導体回路パターン部２９とで構成されている。
【００２２】
信号導体回路パターン部２５は、基台２２の溝２１内に配列された極細同軸線心１０の端面における中心導体１１間のピッチＰ１に合わせて一端が０．５ｍｍのピッチで形成され、他端のピッチＰ２が一端のピッチＰ１、すなわち０．５ｍｍよりも狭い０．３ｍｍのピッチで形成されている。
【００２３】
信号導体回路パターン部２５及びグランド導体回路パターン部２９は、極細同軸線心１０の外部導体層１３と電気的に接触しないように、信号導体回路パターン部２５及びグランド導体回路パターン部２９の一部（斜線で示した部分）は、図示しない絶縁フィルムで覆われている。
【００２４】
基台２２及び線心押さえ板２３の材料としては、加工の容易さからプラスチックあるいは金属等、例えばエポキシ樹脂等の硬質プラスチック、ジルコア、ステンレス等が挙げられる。
【００２５】
このように極細多芯ケーブルの端末接続部２０は、基台２２の端面に露出した極細多芯ケーブルの極細同軸線心１０の端面に異方性導電膜２４を挟んでプリント基板２７を接合することにより、プリント基板２７の導体回路パターン２８と極細多芯ケーブルの各極細同軸線心１０とが重ね合わされた部分にのみ異方性導電膜２４内に通電部が形成されるので、極細の線心でも狭ピッチ接続が容易となる。
【００２６】
さて、図５は本発明の極細多芯ケーブルの端末接続部を示す側面図である。
【００２７】
図１に示した端末接続部との相違点は、基台３１とプリント基板３２との接合面が傾斜している点である。
【００２８】
本発明の極細多芯ケーブルの端末接続部３０においては、接合面３１ｂの基台３１の底面３１ａに対する傾斜角αは、３０度〜８０度又は１００度〜１５０度の範囲とするのが好ましい。
【００２９】
このように基台３１とプリント基板３２との接合面を傾斜させることにより、極細同軸線心１０の中心導体及び外部導体層の基台３１端面における露出面積（接合面積）を円から楕円へと大きくすることができ、極細同軸線心１０と導体回路パターン（図示せず。）との機械的接続及び電気的接続を良好なものとすることができる。この場合、導体回路パターンの信号導体回路パターン部及びグランド導体回路パターン部は、極細同軸線心１０の基台３１端面における露出面の形状（円若しくは楕円）に合わせた形状とする。なお、図中３３は線心押さえ板であり、３４は異方性導電膜をそれぞれ示す。
【００３０】
図６は本発明の極細多芯ケーブルの端末接続部に用いられる基台の変形例を示す断面図である。
【００３１】
図６に示す基台４０の図２に示した基台２２との相違点は、各溝４１の開口部４１ａにテーパが設けられている点である。
【００３２】
すなわち、図６に示す基台４０は、溝４１の開口部４１ａの幅Ｗ１が溝４１の底部４１ｂの幅Ｗ２より広くなっている。
【００３３】
このように溝４１の開口部４１ａにテーパが設けられていることにより、極細同軸線心１０を溝４１内に収容するのが容易となり、極細多芯ケーブルの端末接続効率が向上する。
【００３４】
図７は図１に示した端末接続部の異方性導電膜周辺のＶＩＩ−ＶＩＩ線部分拡大断面図である。
【００３５】
異方性導電膜２４は、実装する部材同士を接着するための樹脂絶縁膜（バインダー）５０中に、厚さ方向（図では縦方向）に電気的接続を得るための多数の導電粒子５１が混入されたものである。
【００３６】
図７より導電粒子５１同士が異方性導電膜２４の厚さ方向（図では縦方向）にのみ互いに接触し、面方向（図では横方向）には離隔した状態で配列されていることが分かる。このため、異方性導電膜２４に接触した極細同軸線心１０及びプリント基板２７のうち位置的に重ね合わさった部分、すなわち、中心導体１１と信号導体回路パターン部２５との間、外部導体層１３とグランド導体回路パターン部２９との間のみ導電粒子５１で通電路が形成され、電気的に接続される。残りの導電粒子５１はそのまま異方性導電膜２４内で孤立した状態となるか、中心導体１１、外部導体層１３、信号導体回路パターン部２５及びグランド導体回路パターン部２９のいずれか一個所のみ接続されるだけで通電路を形成しない。
【００３７】
導電粒子５１の材料としては、金、銀、銅、アルミニウム、ニッケルや半田等の導通性の良好な金属粒子の他メッキ等の方法で金属層を表面に設けた樹脂粒子等が挙げられる。異方性導電膜２４の樹脂絶縁膜（バインダー）５０は、基台２２とプリント基板２７との間の密着性の良好な樹脂成分からなる。この樹脂成分としては、熱硬化性のエポキシやウレタンやシリコーン等の樹脂類が挙げられる。この中で望ましいのはアミン類や酸無水物を硬化剤とする熱硬化性のエポキシ樹脂類である。
【００３８】
この異方性導電膜２４は、加熱硬化前に基台に取り付けられるので、ある程度の粘着性（貼り付けた後で落下したり、ずれたりしない程度の粘着性）を有することが望ましい。
【００３９】
この異方性導電膜２４により、極細同軸線心１０の中心導体１１及び外部導体層１３は、それぞれ異方性導電膜２４が含有する導電粒子５１を介して上述した導体回路パターン２８の信号導体回路パターン部２５及びグランド導体回路パターン部２９に電気的に接続されている。
【００４０】
次に本発明の前提技術である極細多芯ケーブルの端末接続方法について説明する。
【００４１】
図８（ａ）〜（ｅ）は本発明の前提技術である極細多芯ケーブルの端末接続方法の一実施の形態を示す工程図である。
【００４２】
接続しようとする複数の極細同軸線心１０を整列させるため、直方体状のブロック６０を準備する（図８（ａ））。
【００４３】
ブロック６０に例えば３本の平行な溝２１を所定のピッチＰ１で形成して基台２２とする。溝２１の形成方法としては、エッチング法、サンドブラスト法が挙げられる。基台２２の材料にプラスチックを用いる場合には、溝２１を有する基台２２の型が形成された金型（図示せず。）内にプラスチック樹脂を注入し、硬化させて基台２２を形成してもよい（図８（ｂ））。
【００４４】
極細多芯ケーブル（図示せず。）の端末部から例えば３本の極細同軸線心１０を取り出し、それら３本の極細同軸線心１０を端面が基台２２の端面２２ａに露出するようにそれぞれの溝２１内に配列し、溝２１内に接着剤（図示せず。）を塗布する（図８（ｃ））。
【００４５】
各溝２１内に配列された極細同軸線心１０の端末部を線心押さえ板２３を用いて挟み込み、基台２２に極細同軸線心１０を固定一体化させる。接着剤としては、例えばホットメルト系接着剤、紫外線硬化樹脂等が挙げられる。
【００４６】
極細同軸線心１０の端面側となる基台２２の端面２２ａにおいて、中心導体１１及び外部導体層１３が露出した３本の極細同軸線心１０の端面が基台２２の端面２２ａと同一面となるように極細同軸線心１０を基台２２ごと研磨し、基台２２に導体露出面（基台の端面）を形成する（図８（ｄ））。
【００４７】
最後に、基台２２の導体露出面に、異方性導電膜２４を挟んでプリント基板２７を固定する。
【００４８】
具体的には、基台２２の導体露出面に、異方性導電膜２４を貼り付け、導体回路パターン２８を熱圧着して固定することになる。このとき、プリント基板２７の表面（図では裏側）に形成された信号導体回路パターン部２５の一端と極細同軸線心１０の導体露出面の中心導体１１とが向かい合うように固定する。この結果、極細同軸線心１０の中心導体１１及び外部導体層１３が異方性導電膜２４により、圧接接合され、電気的に接続される。
【００４９】
以上において、本実施の形態によれば、複数の極細同軸線心１０を基台２２、線心押さえ板２３及び異方性導電膜２４を用いてプリント基板２７に一括接続するため、狭ピッチでも容易に接続が可能となる。この結果、極細多芯ケーブルの端末接続部の接続作業を低コスト化できる。
【００５０】
さらに、中心導体１１と導体回路パターン２８との接続部が、基台とプリント基板との間に挟まれて保護されているので、接続状態が安定する。
【００５１】
なお、本実施の形態では、３本の極細同軸線心１０が接続される端末接続部について述べたが、本発明はこれに限定されるものではなく、極細同軸線心１０の本数が２本以下でも４本以上であってもよく、同軸線心でなく単心線であってもよい。
【００５２】
また、本実施の形態では、基台２２の端面２２ａにおける極細同軸線心１０は、図２に示すように３本を一直線上に配列した場合で説明したが、本発明はこれに限定されるものではなく、図９に示すように複数の溝７０を基台７１の表裏両面に形成して極細同軸線心１０の並びの列が２本となるようにしてもよい。図中、７２は線心押さえ板を示す。
【００５３】
また、図１０に示すように溝８０を基台８１の表裏両面に互い違いになるようにしてもよい。図中、８２は線心押さえ板を示す。なお、極細同軸線心１０の端面の配列に一致するように、プリント基板の導体回路パターン部の端末部の配置を設定することはいうまでもない。
【００５４】
図９及び図１０は図２に示した基台の変形例を示す断面図である。
【００５５】
さらに、プリント基板は、電子部品や光学部品が搭載されたプリント回路基板であってもよい。
【００５６】
さらに、本実施の形態では溝の断面形状が矩形の場合で説明したが、本発明はこれに限定されるものではなく、Ｖ字断面形状やＵ字断面形状であってもよく、極細同軸線心の外周形状に合わせて曲線状にしてもよい。
【００５７】
【発明の効果】
以上要するに本発明によれば、線心が極細でも狭ピッチ接続が容易な極細多芯ケーブルの端末接続部及びその端末接続方法の提供を実現することができる。
【図面の簡単な説明】
【図１】本発明の前提技術である極細多芯ケーブルの端末接続部の一実施の形態を示す外観斜視図である。
【図２】図１のＩＩ−ＩＩ線断面図である。
【図３】図１に示した極細多芯ケーブルの極細同軸線心の断面図である。
【図４】図１に示す端末接続部に用いられるプリント基板である。
【図５】本発明の好適な実施形態を示す極細多芯ケーブルの端末接続部の側面図である。
【図６】図１に示した端末接続部に用いられる基台の変形例を示す断面図である。
【図７】図１に示した端末接続部の異方性導電膜周辺のＶＩＩ−ＶＩＩ線部分拡大断面図である。
【図８】（ａ）〜（ｅ）は本発明の前提技術である極細多芯ケーブルの端末接続方法の一実施の形態を示す工程図である。
【図９】図２に示した基台の変形例を示す断面図である。
【図１０】図２に示した基台の変形例を示す断面図である。
【図１１】従来の細多芯ケーブルの端末接続方法を示す説明図である。
【符号の説明】
１０極細同軸線心
２１溝
２２基台
２３線心押さえ板（線心押さえ部材）
２４異方性導電膜
２５信号導体回路パターン部
２６絶縁性基板
２７プリント基板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a terminal connecting portion of an ultrafine multicore cable and a terminal connecting method thereof.
[0002]
[Prior art]
Conventionally, in order to connect a plurality of extra fine wire cores taken out from the end of an extra fine multi-core cable to a substrate on which a conductor circuit pattern is formed, the end portions of the plural extra fine wire cores are stepped off to form conductors. The line was exposed and the end of the exposed conductor line was soldered onto the conductor circuit pattern.
[0003]
FIG. 11 is an explanatory view showing a conventional terminal connection method for a thin multi-core cable.
[0004]
When connecting a terminal portion of an ultra-fine multi-core cable in which a plurality of ultra-fine coaxial wires are bundled to a signal conductor circuit pattern on a printed circuit board, as shown in FIG. 11, the terminal of the ultra-fine multi-core cable (not shown) is used. The plurality of ultrafine coaxial cores 1 are taken out, the respective terminal portions 1a are stepped off, the central conductor 3, the insulating layer 4 and the external conductor layer 5 are exposed from the jacket layer 2, and the central conductor 3 is attached to the printed circuit board 6. The external conductor layer 5 was solder-connected to the ground conductor circuit pattern portion 8 of the printed circuit board 6 by solder connection to the signal conductor circuit pattern portion 7.
[0005]
[Problems to be solved by the invention]
By the way, with the recent miniaturization and high performance of electrical and electronic equipment, ultrafine multicore cables used in these equipment are desired to be further reduced in diameter and multicore. Is currently under development with an outer diameter of 0.2 mm or less.
[0006]
Further, the miniaturization of the terminal connection portion of the ultrafine multicore cable, which is a connection portion between the terminal portion of the ultrafine multicore cable and the circuit pattern member having the conductor circuit pattern on the surface, is also progressing.
[0007]
However, in a situation where the diameter of the ultrafine wire cores to be connected is reduced and the pitch between the ultrafine wire cores must be connected at a narrow pitch, the conventional connection method shown in FIG. Since the solder connection is performed one by one, there is a problem in that the manufacturing work of the terminal connection portion is very troublesome, the number of work steps increases, and the cost is greatly increased.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and provide a terminal connection portion of an ultra-thin multi-core cable that can be easily connected at a narrow pitch even if the wire core is extremely thin, and a terminal connection method thereof.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the terminal connection portion of the ultrafine multi-core cable of the present invention includes a terminal portion of the conductor wire of the ultrafine multicore cable in which a plurality of ultrafine wire cores having an insulating coating applied to the conductor wire are bundled, A base on which a plurality of grooves for arranging the terminal portions of the ultrafine wire cores at a predetermined pitch are formed in the terminal connecting portions of the ultrafine multicore cable to which the conductor circuit patterns formed on the printed circuit board are respectively connected. And a wire core holding member that holds the end of each fine wire core accommodated in each groove of the base from above each groove, and the end face of the conductor wire is flush with the end face of the base An anisotropic conductive film having a conductivity only in the thickness direction, bonded to the anisotropic conductive film, and a conductor. Insulation so that the circuit pattern overlaps with each conductor wire of the above ultrafine wire core And a printed circuit board formed on the plate, the junction surface between the base and the printed circuit board is obtained by inclined with respect to the bottom surface of the base.
[0010]
In addition to the above configuration, the ultrafine wire core of the terminal connecting portion of the ultrafine multicore cable of the present invention includes a center conductor, an insulator layer coated on the outer periphery of the center conductor, and an outer conductor layer applied on the outer periphery of the insulator layer And a jacket layer coated on the outer periphery of the outer conductor layer, and the conductor circuit pattern of the printed circuit board includes a plurality of signal conductor circuit pattern portions and one end of each signal conductor circuit pattern portion. You may have the ground conductor circuit pattern part formed so that the circumference | surroundings may be surrounded and connected with an external conductor layer.
[0011]
In addition to the above configuration, the ultrafine wire core of the terminal connecting portion of the ultrafine multicore cable of the present invention has an outer diameter of 0.5 mm or less, and the pitch of the groove of the base is in the range of 0.3 mm to 0.7 mm. Is preferred.
[0012]
In addition to the above configuration, the terminal connecting portion of the ultrafine multicore cable of the present invention may be formed such that the pitch of the other end of the signal conductor circuit pattern portion is narrower than the pitch of one end.
[0013]
The terminal connection method of the ultra-fine multi-core cable of the present invention is formed on the end portion of the above-described conductor wire of the ultra-fine multi-core cable obtained by bundling a plurality of ultra-fine wire cores having an insulating coating on the conductor wire, and a printed circuit board. In the terminal connection method of the ultrafine multicore cable for connecting each of the conductor circuit patterns, the end portions of the ultrafine wire cores are arranged in the grooves of the base formed at a predetermined pitch, and the ultrafine wires arranged in each groove are arranged. The end face of the base that is the end face side of the wire core and the end face of each conductor wire are on the same plane, and the joint surface between the base and the printed circuit board is inclined with respect to the bottom face of the base. Polishing the end face of the base and forming the printed circuit board in which one end of the signal conductor circuit pattern portion of the conductor circuit pattern is formed at the same pitch as the groove, the end face of the micro coaxial cable core and one end of the signal conductor circuit pattern portion And so that Across the anisotropic conductive film having a lead wire resistance only in the thickness direction is a method of bonding the end surface of the base.
[0014]
According to the present invention, by connecting the printed circuit board with the anisotropic conductive film sandwiched between the end face of the base where the ultrafine wire core of the ultrafine multicore cable is exposed, the conductor circuit pattern of the printed circuit board and the ultrafine multicore cable are connected. Since the current-carrying portion is formed in the anisotropic conductive film only at the portion where the conductor wire is overlapped, narrow pitch connection is facilitated even with an extremely thin wire core.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is an external perspective view showing an embodiment of a terminal connecting portion of an extra fine multi-core cable, which is a prerequisite technology of the present invention, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 2 is a cross-sectional view of an ultrafine coaxial cable core of the ultrafine multicore cable shown in FIG. In the present embodiment, the case of an extra fine coaxial core as the extra fine core will be described.
[0017]
A micro coaxial cable core 10 shown in FIG. 3 includes a central conductor 11 composed of a single core, an insulator layer 12 provided on the outer periphery of the center conductor 11, and a plurality (20 in the figure) wound around the outer periphery of the insulator layer 12. The outer conductor layer 13 is a book, but is not limited.) And the jacket wire 14 provided on the outer periphery of the outer conductor layer 13. The outer diameter D of the ultrafine coaxial cable core 10 is 0.2 mm, for example.
[0018]
The terminal connection portion 20 shown in FIG. 1 includes a base 22 in which a plurality of grooves 21 for arranging the end portions of the micro coaxial cable core 10 at a predetermined pitch P1 are formed, and in each groove 21 of the base 22 And a wire core holding plate 23 for holding the terminal portion of each accommodated micro coaxial cable core 10 from above each groove 21, and the end surface of each micro coaxial cable core 10 is one end surface of the base 22 (right side in the figure). The end face of each micro coaxial cable core 10 of the base 22 is joined to the exposed end face and has conductivity only in the thickness direction. The printed circuit board 27 is formed on the insulating substrate 26 so that one end of each signal conductor circuit pattern portion 25 is joined to the isotropic conductive film 24 and overlaps each center conductor of the micro coaxial cable core 10. Yes.
[0019]
As shown in FIG. 2, the wire core holding plate 23 has a concavo-convex cross-sectional shape, and each convex portion 23 a can be fitted into each groove 21 of the base 22, and is accommodated in each groove 21. The extra-fine coaxial cable core 10 is arranged and fixed at a predetermined position at a predetermined pitch P1.
[0020]
FIG. 4 is a printed circuit board used in the terminal connection unit shown in FIG.
[0021]
A printed circuit board 27 shown in the figure is obtained by forming a conductor circuit pattern 28 made of a conductive metal such as copper on the surface of a flexible insulating substrate (for example, polyimide film) 26. The conductor circuit pattern 28 includes a plurality of (three in the figure, but not limited) signal conductor circuit pattern portions 25 each having one end (left side in the figure) connected to the center conductor 11 of the micro coaxial cable core 10, and an extra fine line. One (two or more) linear ground conductor circuit pattern portion 29 connected to the outer conductor layer 13 of the coaxial wire core 10 and surrounding the periphery of one end of the signal conductor circuit pattern portion 25. It is configured.
[0022]
The signal conductor circuit pattern portion 25 has one end formed at a pitch of 0.5 mm in accordance with the pitch P1 between the center conductors 11 on the end face of the micro coaxial cable core 10 arranged in the groove 21 of the base 22, and the other end Is formed at a pitch P1 at one end, that is, a pitch of 0.3 mm narrower than 0.5 mm.
[0023]
The signal conductor circuit pattern portion 25 and the ground conductor circuit pattern portion 29 are part of the signal conductor circuit pattern portion 25 and the ground conductor circuit pattern portion 29 so as not to be in electrical contact with the outer conductor layer 13 of the micro coaxial cable core 10. (The portion shown by oblique lines) is covered with an insulating film (not shown).
[0024]
Examples of the material for the base 22 and the wire core holding plate 23 include plastic or metal, for example, hard plastic such as epoxy resin, zir core, stainless steel, and the like because of ease of processing.
[0025]
Thus, the terminal connection part 20 of the ultrafine multicore cable joins the printed circuit board 27 with the anisotropic conductive film 24 sandwiched between the end face of the ultrafine coaxial cable core 10 of the ultrafine multicore cable exposed at the end face of the base 22. As a result, the current-carrying portion is formed in the anisotropic conductive film 24 only in the portion where the conductor circuit pattern 28 of the printed circuit board 27 and each micro-coaxial cable core 10 of the ultra-fine multi-core cable are overlapped. Narrow pitch connection is easy even at the heart.
[0026]
Now, FIG. 5 is a side view showing a terminal connecting portion of the multifilamentary cable of the present invention.
[0027]
The difference from the terminal connection portion shown in FIG. 1 is that the joint surface between the base 31 and the printed board 32 is inclined.
[0028]
In the terminal connecting portion 30 of the multifilamentary cable of the present invention, the inclination angle α relative to the bottom surface 31a of the base 31 of the joint surface 31b is preferably in the range of 30 to 80 degrees or 10 0 150 degrees .
[0029]
By inclining the joint surface between the base 31 and the printed circuit board 32 in this way, the exposed area (joint area) at the end surface of the base 31 of the central conductor and the outer conductor layer of the micro coaxial cable core 10 is changed from a circle to an ellipse. Therefore, the mechanical connection and electrical connection between the micro coaxial cable core 10 and the conductor circuit pattern (not shown) can be improved. In this case, the signal conductor circuit pattern portion and the ground conductor circuit pattern portion of the conductor circuit pattern have a shape that matches the shape of the exposed surface (circle or ellipse) on the end surface of the base 31 of the micro coaxial cable core 10. In the figure, 33 is a wire core holding plate, and 34 is an anisotropic conductive film.
[0030]
FIG. 6 is a cross-sectional view showing a modified example of the base used in the terminal connecting portion of the ultrafine multicore cable of the present invention .
[0031]
The difference between the base 40 shown in FIG. 6 and the base 22 shown in FIG. 2 is that the opening 41a of each groove 41 is tapered.
[0032]
That is, in the base 40 shown in FIG. 6, the width W1 of the opening 41a of the groove 41 is wider than the width W2 of the bottom 41b of the groove 41.
[0033]
Thus, by providing the opening 41a of the groove 41 with a taper, it becomes easy to accommodate the micro coaxial cable core 10 in the groove 41, and the terminal connection efficiency of the micro multi-core cable is improved.
[0034]
FIG. 7 is a partially enlarged sectional view taken along the line VII-VII around the anisotropic conductive film of the terminal connection portion shown in FIG.
[0035]
The anisotropic conductive film 24 includes a large number of conductive particles 51 for obtaining electrical connection in a thickness direction (vertical direction in the figure) in a resin insulating film (binder) 50 for bonding members to be mounted. It is mixed.
[0036]
7, the conductive particles 51 are in contact with each other only in the thickness direction (vertical direction in the figure) of the anisotropic conductive film 24, and are arranged in a separated state in the surface direction (horizontal direction in the figure). I understand. For this reason, the portion of the fine coaxial cable core 10 and the printed circuit board 27 that are in contact with the anisotropic conductive film 24 overlapped with each other, that is, between the center conductor 11 and the signal conductor circuit pattern portion 25, the outer conductor layer. Only between 13 and the ground conductor circuit pattern portion 29, a conduction path is formed by the conductive particles 51 and is electrically connected. The remaining conductive particles 51 are isolated in the anisotropic conductive film 24 as they are, or only one of the central conductor 11, the external conductor layer 13, the signal conductor circuit pattern portion 25, and the ground conductor circuit pattern portion 29. Only connected, does not form a current path.
[0037]
Examples of the material of the conductive particles 51 include resin particles having a metal layer on the surface by a method such as plating other than metal particles having good conductivity such as gold, silver, copper, aluminum, nickel and solder. The resin insulating film (binder) 50 of the anisotropic conductive film 24 is made of a resin component having good adhesion between the base 22 and the printed board 27. Examples of the resin component include resins such as thermosetting epoxy, urethane, and silicone. Of these, preferred are thermosetting epoxy resins using amines or acid anhydrides as curing agents.
[0038]
Since this anisotropic conductive film 24 is attached to the base before heat curing, it is desirable that the anisotropic conductive film 24 has a certain degree of adhesiveness (adhesiveness that does not drop or shift after being attached).
[0039]
With this anisotropic conductive film 24, the central conductor 11 and the outer conductor layer 13 of the micro coaxial cable core 10 are each a signal conductor of the conductor circuit pattern 28 via the conductive particles 51 contained in the anisotropic conductive film 24. The circuit pattern part 25 and the ground conductor circuit pattern part 29 are electrically connected.
[0040]
Next, the terminal connection method of the ultrafine multi-core cable, which is a prerequisite technology of the present invention, will be described.
[0041]
FIGS. 8A to 8E are process diagrams showing an embodiment of a terminal connection method for an ultrafine multicore cable, which is a prerequisite technology of the present invention.
[0042]
A rectangular parallelepiped block 60 is prepared in order to align the plurality of micro coaxial cores 10 to be connected (FIG. 8A).
[0043]
For example, three parallel grooves 21 are formed in the block 60 at a predetermined pitch P1 to form the base 22. Examples of the method for forming the groove 21 include an etching method and a sand blast method. When plastic is used for the material of the base 22, a plastic resin is injected into a mold (not shown) in which a base 22 having a groove 21 is formed, and is cured to form the base 22. You may do it (FIG.8 (b)).
[0044]
For example, three ultrafine coaxial cores 10 are taken out from the end of an ultrafine multicore cable (not shown), and the end faces of the three ultrafine coaxial cores 10 are exposed to the end face 22a of the base 22, respectively. And an adhesive (not shown) is applied in the groove 21 (FIG. 8C).
[0045]
The end portions of the fine coaxial cable cores 10 arranged in the grooves 21 are sandwiched by using a wire core presser plate 23, and the fine coaxial cable cores 10 are fixed and integrated with the base 22. Examples of the adhesive include a hot melt adhesive and an ultraviolet curable resin.
[0046]
At the end surface 22 a of the base 22 that is the end surface side of the micro coaxial cable core 10, the end surfaces of the three micro coaxial cables 10 with the central conductor 11 and the outer conductor layer 13 exposed are flush with the end surface 22 a of the base 22. The fine coaxial cable core 10 is polished together with the base 22 so as to form a conductor exposed surface (end surface of the base) on the base 22 (FIG. 8D).
[0047]
Finally, the printed circuit board 27 is fixed to the conductor exposed surface of the base 22 with the anisotropic conductive film 24 interposed therebetween.
[0048]
Specifically, the anisotropic conductive film 24 is attached to the exposed conductor surface of the base 22 and the conductor circuit pattern 28 is fixed by thermocompression bonding. At this time, one end of the signal conductor circuit pattern portion 25 formed on the front surface (the back side in the figure) of the printed board 27 and the central conductor 11 on the conductor exposed surface of the micro coaxial cable core 10 are fixed so as to face each other. As a result, the center conductor 11 and the outer conductor layer 13 of the micro coaxial cable core 10 are pressure-welded and electrically connected by the anisotropic conductive film 24.
[0049]
In the above, according to the present embodiment, a plurality of micro coaxial cable cores 10 are collectively connected to the printed circuit board 27 using the base 22, the wire core holding plate 23, and the anisotropic conductive film 24. Easy connection. As a result, it is possible to reduce the cost for connecting the terminal connection portion of the ultrafine multicore cable.
[0050]
Furthermore, since the connection part of the center conductor 11 and the conductor circuit pattern 28 is sandwiched and protected between the base and the printed circuit board, the connection state is stabilized.
[0051]
In the present embodiment, the terminal connection portion to which three micro coaxial cables 10 are connected has been described. However, the present invention is not limited to this, and the number of micro coaxial cables 10 is two. The number may be four or more, and may be a single core wire instead of the coaxial core.
[0052]
Further, in the present embodiment, the description has been given of the case where the micro coaxial cables 10 on the end face 22a of the base 22 are arranged in a straight line as shown in FIG. 2, but the present invention is limited to this. Instead of this, a plurality of grooves 70 may be formed on both the front and back surfaces of the base 71 as shown in FIG. In the figure, reference numeral 72 denotes a wire core pressing plate.
[0053]
Further, as shown in FIG. 10, the grooves 80 may be staggered on both the front and back surfaces of the base 81. In the figure, reference numeral 82 denotes a wire core pressing plate. Needless to say, the arrangement of the terminal portions of the conductor circuit pattern portions of the printed circuit board is set so as to match the arrangement of the end faces of the micro coaxial cable core 10.
[0054]
9 and 10 are cross-sectional views showing modifications of the base shown in FIG.
[0055]
Furthermore, the printed circuit board may be a printed circuit board on which electronic components and optical components are mounted.
[0056]
Furthermore, although the case where the cross-sectional shape of the groove is rectangular has been described in the present embodiment, the present invention is not limited to this, and may be a V-shaped cross-sectional shape or a U-shaped cross-sectional shape. You may make it curve shape according to the outer periphery shape of a heart.
[0057]
【The invention's effect】
In summary, according to the present invention, it is possible to provide a terminal connection portion of an ultra-thin multi-core cable and a terminal connection method thereof that can be easily connected at a narrow pitch even if the wire core is very thin.
[Brief description of the drawings]
1 is an external perspective view showing an embodiment of a terminal connection portion of the multifilamentary cable a prerequisite technology of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a cross-sectional view of an extra fine coaxial cable core of the extra fine multi-core cable shown in FIG.
4 is a printed circuit board used in the terminal connection unit shown in FIG.
5 is a side view of the terminal connection portions of the multifilamentary cable of a preferred embodiment of the present invention.
6 is a cross-sectional view showing a modified example of a base used in the terminal connection portion shown in FIG. 1. FIG.
7 is a partially enlarged sectional view taken along line VII-VII around the anisotropic conductive film of the terminal connection portion shown in FIG. 1;
FIGS. 8A to 8E are process diagrams showing an embodiment of a terminal connection method for an ultrafine multicore cable, which is a prerequisite technology of the present invention.
9 is a cross-sectional view showing a modification of the base shown in FIG.
10 is a cross-sectional view showing a modification of the base shown in FIG.
FIG. 11 is an explanatory view showing a conventional terminal connection method for a thin multi-core cable.
[Explanation of symbols]
10 Micro coaxial cable core 21 Groove 22 Base 23 Wire core retainer plate (wire core retainer)
24 Anisotropic Conductive Film 25 Signal Conductor Circuit Pattern 26 Insulating Substrate 27 Printed Circuit Board

Claims

An ultra-thin multi-core cable in which a conductor circuit pattern formed on a printed circuit board and a terminal portion of the above-mentioned ultra-thin multi-core cable in which a plurality of ultra-thin wire cores each having an insulating coating on a conductor wire are bundled are connected to each other. In the terminal connection portion, a base on which a plurality of grooves for arranging the end portions of the above-mentioned ultrafine wire cores at a predetermined pitch are formed, and the end portions of the respective ultrafine wire cores accommodated in the respective grooves of the base A wire core holding member that holds the wire from above each groove, and the end surface of the conductor wire is formed to be flush with the end surface of the base, and the end surface of the base on which the fine wire core is exposed is exposed. An anisotropic conductive film that is bonded and has conductivity only in the thickness direction, and an insulating substrate that is bonded to the anisotropic conductive film so that the conductor circuit pattern overlaps each conductor wire of the ultrafine wire core. and a printed circuit board formed in said base and said printed circuit Terminal connecting portion of the multifilamentary cables, characterized in that is inclined with respect to the bottom surface of the base of the junction plane between.

The fine wire core includes a center conductor, an insulator layer coated on the outer periphery of the center conductor, an outer conductor layer applied on the outer periphery of the insulator layer, and a jacket coated on the outer periphery of the outer conductor layer And the conductor circuit pattern of the printed circuit board is formed so as to surround a plurality of signal conductor circuit pattern portions and one end of each signal conductor circuit pattern portion, and the outer conductor layer. The terminal connection part of the ultrafine multicore cable of Claim 1 which has a ground conductor circuit pattern part connected with.

The terminal connection of the ultrafine multi-core cable according to claim 1 or 2, wherein the ultrafine wire core has an outer diameter of 0.5 mm or less and a pitch of the groove of the base is in a range of 0.3 mm to 0.7 mm. Department.

The terminal connection part of the ultrafine multi-core cable according to any one of claims 1 to 3, wherein a pitch of the other end of the signal conductor circuit pattern part is formed narrower than a pitch of the one end.

An ultra-thin multi-core cable for connecting the terminal portion of the above-mentioned ultra-thin multi-core cable in which a plurality of ultra-thin wire cores each having an insulation coating on the conductor wire are bundled and a conductor circuit pattern formed on a printed circuit board. In the terminal connection method, the end portions of the fine wire cores are arranged in the grooves of the base formed at a predetermined pitch, the end surfaces of the bases that are the end face sides of the fine wire cores arranged in the grooves, and the respective ends. The end surface of the base is polished so that the end surface of the conductor wire is flush with the joint surface between the base and the printed circuit board, and the bottom surface of the base is inclined . A printed circuit board in which one end of the signal conductor circuit pattern portion is formed at the same pitch as the groove is arranged only in the thickness direction so that the end face of the micro coaxial cable core and one end of the signal conductor circuit pattern portion are overlapped. Conductive anisotropic conductive film Sandwiched therebetween Connecting Terminals multifilamentary cables, characterized in that for joining the end face of the base.