JP3924073B2

JP3924073B2 - Connection method between circuit board and conductor piece

Info

Publication number: JP3924073B2
Application number: JP20821798A
Authority: JP
Inventors: 中村　　聡
Original assignee: Rohm Co Ltd
Current assignee: Rohm Co Ltd
Priority date: 1997-09-22
Filing date: 1998-07-23
Publication date: 2007-06-06
Anticipated expiration: 2018-07-23
Also published as: JPH11154780A

Description

【０００１】
【発明の属する技術分野】
本発明は、一方の回路基板と他の部品や回路基板とを接続しやすいように、一方の回路基板の端子パッドに導体片の一端部を接続して、その回路基板の端部から導体片の他端部が突出するように、回路基板の端部に導体片を接続する回路基板と導体片とを接続する接続方法に関する。さらに詳しくは、導体片が斜めに傾いたり、位置ずれして接続されないで、正確に接続され得る回路基板と導体片とを接続する接続方法に関する。
【０００２】
【従来の技術】
従来回路基板の電極パッド上に電子部品や接続用の金属片などをハンダ付けなどにより接続する場合に、回路基板にスルーホールを設けないで、電極パッド上にハンダクリームなどを印刷などにより塗布して直接電子部品のリード部や金属片などを載置し、リフロー炉などでハンダ付けする面実装で行われる場合がある。この場合、その両端部とか、少なく共２か所以上でハンダ付けする場合は、ハンダが溶融するときの表面張力により、電極パッド上にその電子部品のリードや金属片が吸い寄せられるセルフアライメント効果が働き、正確な位置に自動的に修正されてハンダ付けされる。これは、たとえば図８（ａ）に示されるように、固定された２枚の基板３１、３２の端部に設けられる端子パッド３１ａ、３２ａに金属片３３を接続する場合も同様で、端子パッド３１ａ、３２ａ上にクリームハンダ（図示せず）などを塗布し、金属片３３を載置してリフロー炉に入れてクリームハンダを溶融することにより、金属片３３の位置が少々ずれて載置されていても、セルフアラメントにより正確な位置で接続される。
【０００３】
一方、図８（ｂ）に示されるように、１枚の回路基板３１の端部の端子パッド３１ａに金属片３３の一端部のみを接続し、その他端部を回路基板３１から露出させて他の回路基板と接続させるような場合、他端部がフリーな状態で一端部のみを回路基板とハンダ付けなどにより接続しなければならない。
【０００４】
【発明が解決しようとする課題】
前述のように、回路基板の端部に金属片のような導体片の一端部のみを固着して、その他端部が回路基板から突出するように接続する場合、導体片を載置してもその位置が不安定で一定の方向で正確な位置に固着することができない。導体片の他端部側にダミーの回路基板または回路基板を連結している枠などの耳部を設けて両端部でほぼ同じ高さになるようにして固着しようとしても、その他端部はハンダ付けされないため、セルフアライメントによる位置修正がなされない。そのため、金属片などを正確に位置決めして載置しても、リフロー炉などに移動する際に金属片などが移動して位置ずれや傾きが生じ、正確な位置に固着されないという問題がある。
【０００５】
本発明は、このような問題を解決するためになされたもので、回路基板の端部に導体片の一端部のみを固着し、導体片の他端部をフリーな状態で回路基板から突出するように導体片を接続する場合に、導体片が左右や上下に傾いたり、位置ずれが生じたりしないで、正確な向きで回路基板と平行に固着されるような回路基板と導体片とを接続する接続方法を提供することを目的とする。
【０００９】
本明細書において、他の部品とは、たとえば電池の電極と接続するための電池ボックスなどの電気部品や他の回路基板の端子パッドなど、前記回路基板の端子パッドを電気部品や回路に電気的に接続してさらに電気回路を形成し得るものを意味する。また、凹部とは、導体片の突起と嵌合し得る窪みを意味し、回路基板を貫通するスルーホールも含む意味である。
【００１１】
【課題を解決するための手段】
本発明の、回路基板の端部で、一端部を該回路基板の端子パッドに固着し、他端部を該回路基板から突出するように、リボン状で少なくとも接続面が平坦面の導体片を接続する回路基板と導体片との接続方法は、（ａ）前記回路基板が、該回路基板と連結部で連結し、該回路基板を連結部から分離後に除去される耳部を有し、該回路基板の端子パッド上に導電性ペーストを塗布すると共に、前記導体片の他端部に対応する部分の前記耳部に導体片の固着後離脱可能な接着剤を塗布し、ついで前記導体片の両端部が前記端子パッドと前記接着剤とに重なるように前記導体片を載置し、（ｂ）前記導体片が載置された回路基板および耳部を加熱炉に入れて前記一端部と端子パッドとを固着し、（ｃ）前記連結部、および前記接着剤と前記導体片との接続部を分離することにより、前記耳部を前記回路基板から除去することを特徴とする。
【００１２】
ここに耳部とは、回路基板を複数個連結するための枠部を意味するが、回路基板同士が連結部を介して配列される場合はその隣接する相手側の基板も含む意味である。また、導体片の固着後離脱可能な接着剤とは、導体片の固着のための加熱により接着強度が低下する接着剤や温度の上昇に拘らず接着強度が非常に弱く、簡単に離脱することができる接着剤などを意味する。
【００１３】
本発明の回路基板と導体片との接続方法の他の形態は、（ｄ）前記回路基板を、該回路基板と連結部で連結し、該回路基板を連結部から分離後に除去される耳部を有するように作製し、（ｅ）前記導体片の前記他端部側に、該導体片の接続後に分離除去する捨て耳部が設けられるように前記導体片を作製し、（ｆ）前記導体片を前記回路基板の端子パッドに固着する際に前記導体片の捨て耳部を該回路基板の耳部に同時に固着し、（ｇ）その後回路基板の耳部を分離除去する際に前記導体片の捨て耳部を切断除去することを特徴とする。
【００１４】
ここに導体片の捨て耳部とは、製造段階の便宜のため導体片の端部に設けられた付属部分で、最終的には除去される部分を意味する。
【００１５】
【発明の実施の形態】
つぎに、本発明の回路基板と導体片との接続方法について図面を参照しながら説明をする。
【００１６】
回路基板と導体片との接続方法により接続された接続体は、たとえば図１（ａ）に回路基板と導体片との分解斜視図が示されるように、電気回路が形成される回路基板１と、その回路基板１の端部で、回路基板１の端子バッド２に一端部３ａが接続され、かつ、他端部３ｂが回路基板１から突出し他の部品などに接続し得るように端子パッド２に固着される導体片３とからなっており、導体片３の一端部３ａに突起３ｃが形成されている。そして、端子パッド２にはスルーホールのような凹部２ｃが設けられ、導体片３の突起３ｃが端子パッド２の凹部２ｃに挿入（嵌合）された状態で回路基板１と導体片３とが導電性材料により固着されている。
【００１７】
回路基板１は、たとえばエポキシ、ガラスエポキシ、紙エポキシなどからなる基板に配線が印刷されたプリント基板などを用いることができる。そのプリント基板の配線（図示せず）と接続されるように、ＩＣなどの電子部品（図示せず）が搭載されて、所望の電気回路が形成されている。この回路基板１はセットなどに組み込まれて、そのセット内でたとえば電池の電極と接続するための電池ボックスなどの他の電気部品や回路基板などと電気的に接続するため、回路基板１の端部に端子パッド２（図１（ａ）では１個の端子パッド部のみが示されている）が設けられている。
【００１８】
端子パッド２は、回路基板１に設けられる配線パターンと同時に形成されるもので、銅箔などの金属膜パターンからなっている。すなわち、回路基板１の表面の全面に設けられた銅箔などの金属膜をエッチングしてパターニングすることにより、配線パターンと共に形成されている。この端子パッド２の一部に後述する導体片３の突起３ｃと対応する部分（導体片３の一端部３ａを端子パッド２上に位置合せして接着する際の突起３ｃと一致する場所）に凹部２ｃが形成されている。この凹部２ｃは、基板にスルーホールを形成する際に、そのスルーホールと同様に形成される。この凹部２ｃは、導体片３の突起３ｃが挿入し得る凹部であればよく、基板を貫通したスルーホールでも、貫通しないで基板の表面に形成される凹みでもよい。
【００１９】
導体片３は、たとえば厚さが１００〜１５０μｍ程度のＮｉ板などが３〜５ｍｍ程度の幅（電流量により変る）で、１０ｍｍ程度の長さのリボン状に形成されている。この導体片３の他端部３ｂは、前述のように、たとえば電池ボックスなどと溶接などにより接続されるため、Ｎｉ板などが好ましい。しかし、他の回路基板の端子パッドと接続する場合などで導電性接着剤またはハンダ付けなどで接続する場合には銅板など他の金属板でもよい。そして、図１（ｂ）に導体片３の側面図が示されるように、その一端部３ａに前述の端子パッド２の凹部２ｃに挿入（嵌合）し得る突起３ｃが形成されている。この突起３ｃは、前述のプレス加工などにより導体片３を形成する際に、プレス金型に突起部を形成しておくことにより、打抜きの際に打跡として形成される。
【００２０】
突起３ｃは、この打跡の例に限らず、前述の端子パッド２に設けられるスルーホールなどの凹部２ｃと嵌合し得るものであればよい。したがって、たとえば図２〜４に図１と同様の図が示されるように、他の形状でもよい。すなわち、図２に示される例は、導体片３を打ち抜く際に、突起の形成部も円形に打ち抜き、その際に裏面側に発生するバリを除去しないでそのまま残すように形成された突起３ｃでもよい。この場合も前述と同様の凹部２ｃを端子パッド２部に形成しておき、このバリの外周がその凹部２ｃに挿入されればよい。
【００２１】
また、図３に示されるように、一端部３ａの先端のコーナ部を下向きに折り曲げて突起３ｃが形成されてもよい。このような突起３ｃは、導体片３を打ち抜く際に下金型のコーナ部のエッジを取っておくことにより、導体片３の打ち抜きと同時に形成される。この場合の端子パッド２の凹部２ｃは、図３に示されるように導体片３のコーナの突起３ｃと対応するところに２か所で形成される。このような構造にすることにより、２か所で位置決めがなされるため、回転による位置ずれを防止しやすい。
【００２２】
さらに図４に示されるように、端子パッド２の４隅に対応して４か所に折曲部を形成して突起３ｃとすることもできる。この場合の突起３ｃの形成も図３の場合と同様に導体片３の打ち抜きの際の下金型の対応する位置に逃げを作っておくことにより簡単に形成される。この場合の端子パッド２の凹部２ｃは、図４に示されるように、その４隅で基板にスルーホールを形成すると共にその上の銅箔２部分を除去しておくことにより形成される。
【００２３】
前述の回路基板１の電極パッドや端子パッドにクリームハンダを印刷などにより塗布して所定の位置に所定のＩＣなどの電子部品を搭載（図示せず）し、さらに導体片３をその一端部３ａが端子パッド２上に重なるように載置する。この際、端子パッド２の凹部２ｃ内にもクリームハンダが塗布されており、その中に前述の導体片３の突起３ｃが挿入される。そのため位置決めされて載置された導体片３はクリームハンダを介して固定される。その後、リフロー炉に入れてハンダが溶融する温度にすることにより、本発明の回路基板１の端子パッド２に導体片３が固着された回路基板１と導体片３との接続体が得られる。
【００２４】
本発明の接続体によれば、回路基板１の端子パッド２に固着される導体片３の一端部３ａに、突起３ｃが形成されると共に、端子パッド２にもその突起３ｃを挿入し得る凹部２ｃが形成されている。そのため、導体片３をしっかりと位置決めして端子パッド２上に載置することにより、リフロー炉への移動などにより導体片３が移動することなく正確な位置で、そのまま固着される。その結果、他端部３ｂが回路基板１の端部から突出し、別の部品や回路基板の端子パッドなどと接続され得るようにフリーの状態になった導体片３が正確な向きで、かつ、正確な位置で接続された回路基板１が得られる。
【００２５】
図５は、導体片３の位置ずれを生じないように正確に固着しながら、さらに導体片と端子パッド２との接着強度が充分に得られるようにその接着強度を向上させる構造の例を示す図である。すなわち、この例は、導体片３の一端部３ａの中心部に前述の打跡による突起３ｃが形成されると共に、その先端部を接着面と反対側に折り曲げた折曲部３ｄが形成されている。この折曲部３ｄの形成は、前述の突起３ｃの形成と同様に、導体片３を形成する打抜金型の形状に突起および逃げ部を設けておくことにより、簡単に形成される。すなわち、下金型の一端部側の先端部に突起を形成しておき、上金型にその逃げを形成しておくことにより、図５（ａ）に示されるような折曲部３ｄが形成される。
【００２６】
このような折曲部３ｄが形成された導体片３の一端部をその突起３ｃが端子パッド２の凹部２ｃに挿入されるように重ね合わせ、前述と同様にリフロー炉でクリームハンダ４を溶融すると、そのハンダ４は接合面で接着するのみではなく、図５（ｂ）に示されるように、その折曲部３ｄ側にもハンダが上ってハンダフィレット４ａが形成される。このハンダフィレット４ａは、端子パッド２と折曲部３ｄとの間に形成されるため、確実にハンダによる接着がなされる。すなわち、重ね合せた面だけでは必ずしもハンダがきれいに流れて接着しない場合があり得るが、この離れた部分にハンダが上ればハンダが完全に溶融して流れたことを示しており、ハンダ付け強度が充分に向上すると共に、その確認を一目で行うことができる。
【００２７】
図６は、回路基板１に導体片３をずれないように接続する他の方法を示す説明図である。この例は、導体片３や端子パッド２に突起や凹部を設けなくても正確な位置で、かつ、正確な向きに導体片３の一端部３ａのみを端子パッド２に接続するものである。すなわち、まず図６（ａ）に示されるように、耳部５に図示しない連結部により連結された回路基板１の端子パッド２にクリームハンダ６を印刷などにより塗布し、同時に導体片３の他端部３ｂ側に対応する耳部５に導体片３を固着後に容易に剥離することができる接着剤７を塗布する。導体片３を固着後に容易に剥離することができる接着剤７とは、たとえば常温では接着力を有しながら導体片３をハンダ付けする温度ではその接着力がなくなり、その後容易に剥離することができる、たとえば日東電工（株）製の商品名リバアルファのような接着剤、または常温でもハンダ付け温度程度になっても弱い接着力で一応くっついてはいるが、剥離しようと思えば容易に剥離することができる接着力の弱いリフロー用接着剤を使用することができる。
【００２８】
つぎに、図６（ｂ）に示されるように、導体片３をその一端部３ａが端子パッド２の上に重なり、他端部３ｂが前述の接着剤６上に重なるように位置決めされた自動機などによりマウントする。そして、そのままの状態でリフロー炉などに入れてクリームハンダを溶融し、導体片３の一端部３ａと回路基板１の端子パッド２とを固着する。
【００２９】
つぎに、図６（ｃ）に示されるように、リフロー炉から取り出して、回路基板１と図示しない連結部により接続された耳部５を連結部で切断すると共に、導体片３と接着剤７との接続部分を剥離して回路基板１を耳部５から分離することにより、回路基板１の端部において導体片３がその一端部３ａで端子パッド２に固着された回路基板１が得られる。
【００３０】
この方法によれば、導体片３を実装するときは、マウンターなどにより正確に位置合せされて実装され、そのときその他端部３ｂは接着剤７により接着されているため、その後のリフロー炉への移動などにより導体片３が動いて位置ずれが生じたり、向きが傾くなどという不都合は発生しない。しかも、接着剤はリフロー炉でのハンダ付け後に容易に剥離することができるため、端子パッド２と導体片３とが固着された後は接着剤７は耳部５と共に簡単に除去される。その結果、正確な位置で導体片３が回路基板１に接続された接続体が簡単に得られる。もちろん、この場合も前述と同様な突起３ｃや折曲部３ｄを設けることにより、一層正確な位置精度で回路基板１に導体片３を固着することができたり、ハンダの接着強度を向上させることができる。
【００３１】
図７は、回路基板１に導体片３をずれないように接続する他の実施形態を示す説明図である。この例は、導体片３の他端部３ｂ側に捨て耳部３ｆを設け、この捨て耳部３ｆを、導体片３の一端部３ａを回路基板１の端子パッド２にハンダ付けする際に、回路基板１の耳部５に一緒にハンダ付けするものである。
【００３２】
すなわち、図７（ａ）に回路基板１に導体片３を接続する際の分解斜視図が示されるように、導体片３の他端部３ｂ側に捨て耳部３ｆが形成されると共に、回路基板１側は、その導体片３が接続される部分に端子パッド２が銅箔などにより形成されると共に、導体片３が接続される際の、その耳部５における導体片３の捨て耳部３ｆに対応する部分にも、たとえば銅箔による接続部５１が形成されている。なお、回路基板１の耳部５は、図示されていないが、回路基板１と枠部で接続されている。図７（ａ）に示される例では、回路基板１の耳部５の接続部５１の内側（回路基板１側）には、後述する導体片３の捨て耳部３ｆを切断する際の切断作業の容易化のため、開口部５２（スルーホール）が設けられている。この回路基板１の端子パッド２および接続部５１に、たとえばクリームハンダを塗布し、導体片３をその一端部３ａが端子パッド２の上に重なり、他端部３ｂ側の捨て耳部３ｆが接続部５１上に重なるように位置決めされたマウンターなどにより実装する。
【００３３】
ついで、そのままの状態でリフロー炉などに入れてクリームハンダを溶融することにより、図７（ｂ）に示されるように、導体片３の一端部３ａと回路基板１の端子パッド２、および導体片３の捨て耳部３ｆと回路基板１の耳部５の接続部５１とを同時に固着する。この際、クリームハンダが溶融すると、表面張力により球状になろうとし、導体片３の端部はその表面に沿って移動する。そのため、たとえ回路基板１の側辺に直角に導体片３が載置されていなくても、直角方向に位置修正され、そのまま固化することにより自己整合されて固定される。
【００３４】
その後、回路基板１の耳部５をプレスにより切り離す際に、図７（ｃ）に切断線Ｓで示されるように、導体片３の捨て耳部３ｆをプレスにより同時に切断する。この際、前述のように回路基板１の耳部５の接続部５１の近傍に開口部５２が設けられていることにより、導体片３の捨て耳部３ｆを連結する部分のみの切断用の金型により導体片３とその下側の耳部５を切断し、プレスの切断刃を必要以上に幅広く形成する必要がない。しかし、開口部５２は設けられていなくてもよい。その結果、図７（ｃ）に実線で示されるように、回路基板の端子パッド２部に一端が接続され、他端部が溶接できるように解放された状態で導体片３が固定される。
【００３５】
この接続方法によれば、導体片３の両端部が共にリフロー炉で同時にハンダ付けにより固定することができるため、導体片３が少々傾いて端子パッド２上に載置されても、ハンダが溶けて溶融状態になるときに自己整合により端子パッド２と接続部５１の方向に導体片３の位置が整合されて接着される。そのため、ハンダ付けのずれがなく正確な位置で簡単に接続することができる。しかも、他端側の捨て耳部３ｆは回路基板１の耳部５を取り除く際に同時に分離することができるため、工数増には全然ならず、安価に確実に接続することができる。
【００３６】
前述の各例では、導体片と端子パッドとの接続をハンダにより行ったが、ハンダに限らず他の熱硬化性の導電性接着剤などにより行ってもよい。さらに、前述の種々の突起の形状を組み合せて複数種類の突起の組合せとすることもできる。そうすることにより、より一層位置ずれの防止を図ることができる。
【００３７】
【発明の効果】
本発明によれば、導体片の位置ずれや傾きなどがなく、その一端部のみを回路基板に固着する接続体が得られるため、導体片の他端部を他の部品や回路基板などに精度よく接続することができる。その結果、軽薄短小化する電気機器において、一層の小形化に寄与する。
【００３８】
さらに、導体片の先端部を接着面と反対側に折り曲げる折曲部が形成されることにより、導体片の位置が正確に固着されると共に、その接着強度を充分に向上させることができる。
【図面の簡単な説明】
【図１】回路基板と導体片との接続体の一例の分解斜視説明図である。
【図２】図１の突起の変形例の説明図である。
【図３】図１の突起の他の変形例の説明図である。
【図４】図１の突起のさらに他の変形例の説明図である。
【図５】本発明の接続体の他の実施形態の説明図である。
【図６】本発明の回路基板と導体片との接続方法の一実施形態の説明図である。
【図７】本発明の回路基板と導体片との接続方法の他の実施形態の説明図である。
【図８】従来の回路基板と導体片との接続構造の説明図である。
【符号の説明】
１回路基板
２端子パッド
２ｃ凹部
３導体片
３ａ一端部
３ｂ他端部
３ｃ突起
３ｄ折曲部
３ｆ捨て耳部[0001]
BACKGROUND OF THE INVENTION
In the present invention, one end of a conductor piece is connected to a terminal pad of one circuit board so that one circuit board can be easily connected to another component or circuit board, and the conductor piece is connected from the end of the circuit board. The present invention relates to a connection method for connecting a circuit board and a conductor piece that connect the conductor piece to the end of the circuit board so that the other end of the circuit board protrudes. More specifically, the present invention relates to a connection method for connecting a circuit board and a conductor piece that can be accurately connected without the conductor piece being obliquely tilted or being displaced in position.
[0002]
[Prior art]
When connecting electronic parts or metal pieces for connection to the electrode pads on a conventional circuit board by soldering or the like, solder cream or the like is applied to the electrode pads by printing or the like without providing through holes in the circuit board. In some cases, it is performed by surface mounting in which a lead part of an electronic component or a metal piece is directly placed and soldered in a reflow furnace or the like. In this case, when soldering at both ends or at least two places, the self-alignment effect that the leads and metal pieces of the electronic component are sucked onto the electrode pad by the surface tension when the solder melts. Working, automatically corrected to the correct position and soldered. For example, as shown in FIG. 8A, the same applies to the case where the metal piece 33 is connected to the terminal pads 31a and 32a provided at the ends of the two fixed substrates 31 and 32. By applying cream solder (not shown) or the like on 31a and 32a, placing the metal piece 33 and placing it in a reflow oven to melt the cream solder, the position of the metal piece 33 is slightly shifted. Even if it is, it is connected at an accurate position by self-arament.
[0003]
On the other hand, as shown in FIG. 8B, only one end of the metal piece 33 is connected to the terminal pad 31a at the end of one circuit board 31, and the other end is exposed from the circuit board 31. When connecting to the circuit board, it is necessary to connect only one end to the circuit board by soldering or the like with the other end being free.
[0004]
[Problems to be solved by the invention]
As described above, when only one end of a conductor piece such as a metal piece is fixed to the end of the circuit board and the other end protrudes from the circuit board, the conductor piece may be placed. The position is unstable and cannot be fixed at an accurate position in a certain direction. Even if you try to secure the dummy circuit board or ears such as a frame connecting the circuit board on the other end side of the conductor piece so that they are almost the same height at both ends, the other end is soldered Since it is not attached, the position is not corrected by self-alignment. Therefore, even if a metal piece or the like is accurately positioned and placed, there is a problem that when the metal piece or the like is moved to a reflow furnace or the like, the metal piece or the like is moved to cause displacement or inclination, and the metal piece is not fixed at an accurate position.
[0005]
The present invention has been made to solve such a problem. Only one end of a conductor piece is fixed to an end of a circuit board, and the other end of the conductor piece protrudes from the circuit board in a free state. When connecting the conductor pieces in this way, the circuit board and the conductor pieces that are fixed in parallel with the circuit board in the correct orientation without tilting the conductor pieces left and right or up and down or being displaced. An object is to provide a connection method for connection .
[0009]
In this specification, the term “ other component” refers to, for example, an electrical component such as a battery box for connecting to a battery electrode, or a terminal pad of another circuit substrate, and the like. It means that it can be connected to and further form an electric circuit. Further, the recess means a recess that can be fitted to the protrusion of the conductor piece, and includes a through hole that penetrates the circuit board.
[0011]
[Means for Solving the Problems]
Of the present invention, at the end of the circuit board, fixed at one end portion to the terminal pad of the circuit board, so as to project the other end from the circuit board, the conductor pieces of at least the connection surface is a flat surface in ribbon The method of connecting the circuit board to be connected and the conductor piece includes: (a) the circuit board is connected to the circuit board at a connecting portion, and has an ear portion that is removed after the circuit board is separated from the connecting portion; A conductive paste is applied onto the terminal pads of the circuit board, and an adhesive that can be removed after the conductor piece is fixed is applied to the ear portion corresponding to the other end of the conductor piece, and then the conductor piece The conductor piece is placed so that both end portions overlap the terminal pad and the adhesive, and (b) the circuit board and the ear portion on which the conductor piece is placed are placed in a heating furnace, and the one end portion and the terminal And (c) the connecting portion, and the adhesive and the conductor piece. By separating the connection portions, and removing the ear portion from the circuit board.
[0012]
Here, the term “ear part” means a frame part for connecting a plurality of circuit boards, but when the circuit boards are arranged via the connection part, it means that the adjacent board is also included. In addition, the adhesive that can be removed after the conductor piece is fixed is an adhesive whose adhesive strength is reduced by heating for fixing the conductor piece, and the adhesive strength is very weak regardless of the rise in temperature. It means an adhesive that can be used.
[0013]
The other form of the connection method of the circuit board and the conductor piece of the present invention is as follows: (d) The circuit board is connected to the circuit board by a connecting part, and the ear part is removed after the circuit board is separated from the connecting part. (E) The conductor piece is prepared such that a throw-away portion for separation and removal after the connection of the conductor piece is provided on the other end side of the conductor piece, and (f) the conductor When the piece is fixed to the terminal pad of the circuit board, the discarding ear portion of the conductor piece is simultaneously fixed to the ear portion of the circuit board; and (g) the conductor piece is separated and removed thereafter. It is characterized by cutting and removing the discarded ear portion.
[0014]
Here, the throwing-off portion of the conductor piece means an attached portion provided at an end portion of the conductor piece for the convenience of the manufacturing stage, and finally a portion to be removed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, how to connect the circuit board and the conductor pieces of the present invention will be described with reference to the drawings.
[0016]
Circuitry substrate and connecting method by the connected connection of the conductor piece, for example, as an exploded perspective view of the circuit board and the conductor pieces in FIGS. 1 (a) is shown, the circuit board 1, an electrical circuit is formed And a terminal pad at the end of the circuit board 1 so that one end 3a is connected to the terminal pad 2 of the circuit board 1 and the other end 3b protrudes from the circuit board 1 and can be connected to other components. 2, a conductor piece 3 fixed to 2, and a protrusion 3 c is formed at one end 3 a of the conductor piece 3. The terminal pad 2 is provided with a recess 2c such as a through hole, and the circuit board 1 and the conductor piece 3 are connected to each other with the protrusion 3c of the conductor piece 3 inserted (fitted) into the recess 2c of the terminal pad 2. It is fixed by a conductive material.
[0017]
As the circuit board 1, for example, a printed board in which wiring is printed on a board made of epoxy, glass epoxy, paper epoxy, or the like can be used. An electronic component (not shown) such as an IC is mounted so as to be connected to the wiring (not shown) of the printed board, thereby forming a desired electric circuit. The circuit board 1 is incorporated in a set or the like, and is electrically connected to other electrical components such as a battery box for connecting to the electrode of the battery or the circuit board in the set. A terminal pad 2 (only one terminal pad part is shown in FIG. 1A) is provided in the part.
[0018]
The terminal pad 2 is formed at the same time as the wiring pattern provided on the circuit board 1 and is made of a metal film pattern such as a copper foil. That is, it is formed together with the wiring pattern by etching and patterning a metal film such as a copper foil provided on the entire surface of the circuit board 1. A part of the terminal pad 2 corresponding to a projection 3c of a conductor piece 3 to be described later (a place where the one end 3a of the conductor piece 3 is aligned with the terminal pad 2 and bonded to the projection 3c). A recess 2c is formed. The recess 2c is formed in the same manner as the through hole when the through hole is formed in the substrate. The recess 2c may be a recess into which the protrusion 3c of the conductor piece 3 can be inserted, and may be a through-hole penetrating the substrate or a recess formed on the surface of the substrate without penetrating.
[0019]
The conductor piece 3 is formed in a ribbon shape having a width of about 3 to 5 mm (varies depending on the amount of current) and a length of about 10 mm, for example, a Ni plate having a thickness of about 100 to 150 μm. As described above, since the other end 3b of the conductor piece 3 is connected to, for example, a battery box by welding or the like, a Ni plate or the like is preferable. However, other metal plates such as a copper plate may be used when connecting with a terminal pad of another circuit board and when connecting with a conductive adhesive or soldering. Then, as shown in a side view of the conductor piece 3 in FIG. 1B, a protrusion 3c that can be inserted (fitted) into the recess 2c of the terminal pad 2 is formed at one end 3a. The protrusion 3c is formed as a mark when punching by forming a protrusion on the press die when the conductor piece 3 is formed by the above-described press working or the like.
[0020]
The protrusion 3c is not limited to the example of the stroke, and any protrusion that can be fitted to the recess 2c such as a through hole provided in the terminal pad 2 described above may be used. Therefore, other shapes may be used, for example, as shown in FIGS. That is, in the example shown in FIG. 2, when the conductor piece 3 is punched, the protrusion forming portion is also punched in a circular shape, and the protrusion 3 c formed so as to remain without removing the burr generated on the back surface at that time. Good. In this case as well, the same recess 2c as described above may be formed in the terminal pad 2 and the outer periphery of this burr may be inserted into the recess 2c.
[0021]
Moreover, as FIG. 3 shows, the protrusion 3c may be formed by bending the corner part of the front-end | tip of the one end part 3a downward. Such a protrusion 3 c is formed simultaneously with the punching of the conductor piece 3 by removing the edge of the corner portion of the lower mold when the conductor piece 3 is punched. In this case, the recess 2c of the terminal pad 2 is formed at two locations corresponding to the corner projections 3c of the conductor piece 3, as shown in FIG. By adopting such a structure, positioning is performed at two locations, so that it is easy to prevent displacement due to rotation.
[0022]
Further, as shown in FIG. 4, it is also possible to form bent portions at four places corresponding to the four corners of the terminal pad 2 to form the protrusions 3c. In this case, the projection 3c can be easily formed by making a relief at a corresponding position of the lower die when the conductor piece 3 is punched out as in the case of FIG. As shown in FIG. 4, the recess 2c of the terminal pad 2 in this case is formed by forming through holes in the substrate at the four corners and removing the copper foil 2 portion thereon.
[0023]
A cream solder is applied to the electrode pads and terminal pads of the circuit board 1 by printing or the like, and an electronic component such as a predetermined IC is mounted (not shown) at a predetermined position, and the conductor piece 3 is connected to one end 3a thereof. Is placed so as to overlap the terminal pad 2. At this time, cream solder is also applied in the recess 2c of the terminal pad 2, and the protrusion 3c of the conductor piece 3 is inserted therein. Therefore, the conductor piece 3 positioned and placed is fixed via cream solder. Then, the connection body of the circuit board 1 and the conductor piece 3 with which the conductor piece 3 was fixed to the terminal pad 2 of the circuit board 1 of this invention is obtained by making it the temperature which solder | pewter melt | dissolves in a reflow furnace.
[0024]
According to the connection body of the present invention, the protrusion 3 c is formed at the one end 3 a of the conductor piece 3 fixed to the terminal pad 2 of the circuit board 1, and the recess into which the protrusion 3 c can be inserted into the terminal pad 2. 2c is formed. Therefore, by positioning the conductor piece 3 firmly and placing it on the terminal pad 2, the conductor piece 3 is fixed as it is at an accurate position without moving due to movement to the reflow furnace or the like. As a result, the other end portion 3b protrudes from the end portion of the circuit board 1, and the conductor piece 3 which is in a free state so that it can be connected to another component, a terminal pad of the circuit board or the like is in an accurate orientation, and The circuit board 1 connected at an accurate position is obtained.
[0025]
FIG. 5 shows an example of a structure in which the bonding strength of the conductor piece and the terminal pad 2 is further improved so that the bonding strength between the conductor piece and the terminal pad 2 can be sufficiently obtained while being accurately fixed so as not to cause the positional deviation of the conductor piece 3. FIG. That is, in this example, the protrusion 3c due to the above-described stroke is formed at the central portion of the one end portion 3a of the conductor piece 3, and a bent portion 3d is formed by bending the tip portion thereof on the side opposite to the bonding surface. Yes. The bent portion 3d is easily formed by providing a protrusion and a relief portion in the shape of the punching die for forming the conductor piece 3 in the same manner as the formation of the protrusion 3c described above. That is, by forming a protrusion at the tip of one end of the lower mold and forming a relief in the upper mold, a bent part 3d as shown in FIG. 5A is formed. Is done.
[0026]
When one end of the conductor piece 3 formed with such a bent portion 3d is overlapped so that the protrusion 3c is inserted into the recess 2c of the terminal pad 2, the cream solder 4 is melted in a reflow furnace as described above. The solder 4 is not only bonded at the joining surface, but also as shown in FIG. 5B, the solder rises on the bent portion 3d side to form a solder fillet 4a. Since the solder fillet 4a is formed between the terminal pad 2 and the bent portion 3d, the solder fillet 4a is securely bonded by solder. In other words, solder may not necessarily flow cleanly and adhere on the superposed surfaces alone, but if the solder goes up to this distant part, it indicates that the solder has completely melted and soldered strength. Is sufficiently improved, and the confirmation can be performed at a glance.
[0027]
FIG. 6 is an explanatory view showing another method for connecting the conductor piece 3 to the circuit board 1 so as not to be displaced. In this example, only one end portion 3a of the conductor piece 3 is connected to the terminal pad 2 in an accurate position and in an accurate direction without providing a protrusion or a recess in the conductor piece 3 or the terminal pad 2. That is, first, as shown in FIG. 6A, the cream solder 6 is applied to the terminal pads 2 of the circuit board 1 connected to the ear portion 5 by a connecting portion (not shown) by printing or the like. An adhesive 7 that can be easily peeled off after the conductor piece 3 is fixed is applied to the ear 5 corresponding to the end 3b side. The adhesive 7 that can be easily peeled off after the conductor piece 3 is fixed is, for example, that the adhesive strength is lost at a temperature at which the conductor piece 3 is soldered while having an adhesive force at room temperature, and can be easily peeled off thereafter. Yes, for example, Nitto Denko Co., Ltd. product name such as Riva Alpha, or even at room temperature or soldering temperature, but with a weak adhesive force, but if you want to peel easily peel off It is possible to use an adhesive for reflowing that can be weakly bonded.
[0028]
Next, as shown in FIG. 6B, the conductor piece 3 is positioned so that one end portion 3a thereof overlaps the terminal pad 2 and the other end portion 3b overlaps the above-described adhesive 6. Mount with a machine. Then, the solder paste is melted in a reflow furnace or the like as it is, and the one end 3a of the conductor piece 3 and the terminal pad 2 of the circuit board 1 are fixed.
[0029]
Next, as shown in FIG. 6 (c), the ear piece 5 connected to the circuit board 1 and the connecting portion (not shown) is taken out from the reflow furnace, and the conductor piece 3 and the adhesive 7 are cut off at the connecting portion. The circuit board 1 is obtained in which the conductor piece 3 is fixed to the terminal pad 2 at one end portion 3a at the end portion of the circuit board 1 by separating the connection portion to the edge portion 5 and separating the circuit board 1 from the ear portion 5. .
[0030]
According to this method, when the conductor piece 3 is mounted, the conductor piece 3 is mounted by being accurately aligned by a mounter or the like. At that time, the other end portion 3b is bonded by the adhesive 7, so that it is supplied to the subsequent reflow furnace. There is no inconvenience that the conductor piece 3 is moved due to movement or the like to cause a positional shift or an inclination. Moreover, since the adhesive can be easily peeled after soldering in a reflow furnace, the adhesive 7 is easily removed together with the ears 5 after the terminal pad 2 and the conductor piece 3 are fixed. As a result, a connection body in which the conductor piece 3 is connected to the circuit board 1 at an accurate position can be easily obtained. Of course, in this case as well, by providing the same protrusion 3c and bent portion 3d as described above, the conductor piece 3 can be fixed to the circuit board 1 with more accurate positional accuracy, and the bonding strength of the solder can be improved. Can do.
[0031]
FIG. 7 is an explanatory view showing another embodiment in which the conductor piece 3 is connected to the circuit board 1 so as not to be displaced. In this example, a discarded ear portion 3f is provided on the other end portion 3b side of the conductor piece 3, and this discarded ear portion 3f is soldered to the terminal pad 2 of the circuit board 1 when the one end portion 3a of the conductor piece 3 is soldered. The circuit board 1 is soldered together to the ear 5.
[0032]
That is, as shown in FIG. 7 (a), an exploded perspective view when the conductor piece 3 is connected to the circuit board 1 is shown. On the substrate 1 side, the terminal pad 2 is formed of a copper foil or the like at a portion to which the conductor piece 3 is connected, and the discarding ear portion of the conductor piece 3 in the ear portion 5 when the conductor piece 3 is connected. A connecting portion 51 made of, for example, copper foil is also formed in the portion corresponding to 3f. In addition, although the ear | edge part 5 of the circuit board 1 is not shown in figure, it is connected with the circuit board 1 and the frame part. In the example shown in FIG. 7A, the cutting work when cutting the discarded lug 3 f of the conductor piece 3 to be described later is provided inside (on the circuit board 1 side) the connection portion 51 of the lug 5 of the circuit board 1. In order to facilitate this, an opening 52 (through hole) is provided. For example, cream solder is applied to the terminal pad 2 and the connecting portion 51 of the circuit board 1, and the conductor piece 3 is overlapped with the one end 3 a of the terminal pad 2, and the discarded ear portion 3 f on the other end 3 b side is connected. Mounting is performed by a mounter positioned so as to overlap with the portion 51.
[0033]
Next, the solder paste is melted by putting it in a reflow furnace or the like as it is, and as shown in FIG. 7B, one end portion 3a of the conductor piece 3, the terminal pad 2 of the circuit board 1, and the conductor piece. 3 and the connection part 51 of the ear | edge part 5 of the circuit board 1 are adhere | attached simultaneously. At this time, when the cream solder is melted, it tends to be spherical due to surface tension, and the end of the conductor piece 3 moves along the surface. Therefore, even if the conductor piece 3 is not placed on the side of the circuit board 1 at a right angle, the position of the conductor piece 3 is corrected in the right-angle direction and solidified as it is so as to be self-aligned and fixed.
[0034]
Thereafter, when the ears 5 of the circuit board 1 are separated by pressing, as shown by the cutting line S in FIG. 7C, the discarded ears 3f of the conductor piece 3 are simultaneously cut by pressing. At this time, as described above, the opening 52 is provided in the vicinity of the connection portion 51 of the ear portion 5 of the circuit board 1, so that only a portion for connecting the discard ear portion 3 f of the conductor piece 3 is cut. It is not necessary to cut the conductor piece 3 and the lower ear portion 5 with a mold, and to form a press cutting blade wider than necessary. However, the opening 52 may not be provided. As a result, as shown by a solid line in FIG. 7C, one end is connected to the terminal pad 2 portion of the circuit board and the conductor piece 3 is fixed in a released state so that the other end portion can be welded.
[0035]
According to this connection method, both ends of the conductor piece 3 can be fixed together by soldering in a reflow furnace, so that even if the conductor piece 3 is slightly inclined and placed on the terminal pad 2, the solder is melted. When the molten state is reached, the position of the conductor piece 3 is aligned and bonded in the direction of the terminal pad 2 and the connecting portion 51 by self-alignment. Therefore, it is possible to easily connect at an accurate position with no soldering deviation. In addition, since the discard ear 3f on the other end side can be separated at the same time when the ear 5 of the circuit board 1 is removed, the number of man-hours is not increased and the connection can be reliably and inexpensively made.
[0036]
In each of the above-described examples, the connection between the conductor piece and the terminal pad is performed by solder. However, the connection is not limited to solder but may be performed by another thermosetting conductive adhesive or the like. Furthermore, a combination of a plurality of types of protrusions can be obtained by combining the shapes of the various protrusions described above. By doing so, the position shift can be further prevented.
[0037]
【The invention's effect】
According to the present invention, there is no displacement or inclination of the conductor piece, and a connection body is obtained in which only one end of the conductor piece is fixed to the circuit board, so that the other end of the conductor piece can be accurately attached to other components or circuit boards. Can connect well. As a result, it contributes to further miniaturization in an electric device that is light and thin.
[0038]
Furthermore, by forming a bent portion that bends the tip end portion of the conductor piece to the side opposite to the bonding surface, the position of the conductor piece can be accurately fixed and the adhesive strength can be sufficiently improved.
[Brief description of the drawings]
We are an exploded perspective view of an example of the connection of the Figure 1 circuitry substrate and the conductor strip.
FIG. 2 is an explanatory diagram of a modification of the protrusion of FIG.
FIG. 3 is an explanatory diagram of another modification of the protrusion of FIG. 1;
4 is an explanatory view of still another modification of the protrusion of FIG. 1. FIG.
FIG. 5 is an explanatory diagram of another embodiment of the connection body of the present invention.
FIG. 6 is an explanatory diagram of an embodiment of a method for connecting a circuit board and a conductor piece according to the present invention.
FIG. 7 is an explanatory diagram of another embodiment of a method for connecting a circuit board and a conductor piece according to the present invention.
FIG. 8 is an explanatory view of a conventional connection structure between a circuit board and a conductor piece.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Circuit board 2 Terminal pad 2c Concave part 3 Conductor piece 3a One end part 3b Other end part 3c Projection 3d Bending part 3f Throw away ear part

Claims

At the end of the circuit board on which the electric circuit is formed, a conductor having at least a flat connection surface with a ribbon shape , with one end fixed to the terminal pad of the circuit board and the other end protruding from the circuit board A method of connecting a circuit board and a conductor piece for connecting pieces,
(A) the circuit board, and connected with the circuit board and the connecting portion has ears to be removed circuit board after separation from the connecting portion, applying a conductive paste onto the terminal pads of the circuit board In addition, an adhesive that can be removed after the conductor piece is fixed is applied to the ear portion corresponding to the other end of the conductor piece, and then both end portions of the conductor piece overlap the terminal pad and the adhesive. Place the conductor piece as follows,
(B) Put the circuit board and the ear part on which the conductor piece is placed in a heating furnace, and fix the one end part and the terminal pad,
(C) A method of connecting a circuit board and a conductor piece, wherein the ear part is removed from the circuit board by separating the connecting part and a connection part between the adhesive and the conductor piece.

At the end of the circuit board on which the electric circuit is formed, a conductor having at least a flat connection surface with a ribbon shape , with one end fixed to the terminal pad of the circuit board and the other end protruding from the circuit board A method of connecting a circuit board and a conductor piece for connecting pieces,
(D) The circuit board is connected to the circuit board at a connecting portion, and the circuit board is manufactured to have an ear portion that is removed after separation from the connecting portion,
(E) producing the conductor piece on the other end side of the conductor piece so as to be provided with a discarding ear portion that is separated and removed after the conductor piece is connected ;
(F) When the conductor piece is fixed to the terminal pad of the circuit board, the abandoned portion of the conductor piece is simultaneously fixed to the ear portion of the circuit board;
(G) A method for connecting a circuit board and a conductor piece, wherein the ear part of the conductor piece is cut and removed when the ear part of the circuit board is separated and removed thereafter.