JP2004022214A

JP2004022214A - Conductive suction cup, conductive suction cup sheet, flexible wiring board, its manufacturing method, and terminal leading cable

Info

Publication number: JP2004022214A
Application number: JP2002172037A
Authority: JP
Inventors: Takeshi Sano; 佐野　武; Hideaki Okura; 大倉　秀章
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2002-06-12
Filing date: 2002-06-12
Publication date: 2004-01-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive suction cup having both high conductivity and low elasticity, capable of securing conduction with an electrode terminal easily detachable by being formed in the shape of a suction cup. <P>SOLUTION: An elastic conductor formed into the suction cup shape to make this conductive suction cup 1, is provided with at least a rubber-like elastic resin 15 and conductive fillers 20 mixed in the rubber-like elastic resin, and the conductive fillers form a three dimensional network structure and are brought into conductive contact with each other in the rubber-like resin. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明はメカニカル接触式導通部材としての導電性吸盤の改良に関し、特に弾性変形することによる強い吸盤機能を有しながらも、高い導電機能を発揮することができる導電性吸盤、導電性吸盤シート、フレキシブル配線板、その製造方法、及び端子引き出し用電線に関する。
【０００２】
【従来の技術】
回路配線を構成する電極、端子、接点等を備えた検査対象物に対する導通検査、絶縁検査においては、従来から電極等にメカニカル接触式導通部材を当接させて通電する等の方法が採られている。このようなメカニカル接触式導通部材としては、コンタクトプローブピン、或いはゴム状弾性樹脂に導電性フィラーを混ぜたコネクタ等が各種開発されている。しかし、これまでのメカニカル接触式導通部材においては、電極等との間で電気的導通を確保する手段の他に、電極等との機械的接触を確保する専用治具が必要であった。このため、部品点数の増大、構造の複雑化による大型化、高コスト化という不具合に加えて、従来の導通部材を、複数面に電極を有する３次元構造体ユニットに適用した場合には電極に対する電気的なコンタクトを取ることが難しくなるという欠点があった。
このような従来例として、特開２００２−２５６６９公報には、吸盤機能と導電機能を分離させた吸盤式電極に係る発明が開示されている。この公報には、ゴム、樹脂等の絶縁性の弾性材料から成る吸盤の内部に別部材の電極を配置した構成が開示されているが、このように吸盤機能と導電機能を分離した場合には、部品点数の増大、構造の複雑化が避けられないため、小型化が困難となり、吸着対象物としての電極間ピッチが狭い場合に対応できないという不具合がある。
また、実用新案登録第２５３２５９７号公報には、身体表面に吸着させて通電することにより脂肪組織量等の身体的条件を測定するための金属製吸盤が示されているが、この金属製吸盤自体は弾性変形しないため、身体表面に吸着させるためには、吸盤の反対側に連設した中空吸引部材を操作して吸盤内部を負圧にする必要がある。従って、小型化は不可能であり、しかも吸着対象物が身体表面のように可撓性、弾力性を有した面であれば吸着し易いが、金属製の電極等のように可撓性を有していなかったり、或いは電極面、或いはその周辺に凹凸が存在している面には適用できないという不具合がある。
【０００３】
このような不具合を解決するために、従来から弾性材料から成る吸盤に導電性を持たせて、電極に対する吸着と導通を同時に確保するようにした導電性吸盤が提案されている。吸盤機能と導電機能を一体化させた導電性吸盤は、例えば実開昭６１−６０４７２号公報に開示されている。しかし、従来の導電性吸盤にあっては、吸盤機能を発揮させるための弾力性と、高導電性との両立が困難であった。即ち、従来のゴム状弾性樹脂に導電性フィラーを混練した導電性ゴム（導電性樹脂）は、導電性が低くしかも接触抵抗が不安定であったため、電極に対する確実な吸着力を確保する場合には導電性フィラーの量を減らして導電性を犠牲にせざるを得ない一方で、導電性フィラーを増やして導電性を確保する場合には吸着力を犠牲にせざるを得ないという不具合があった。このため、上記従来の導電性吸盤は、透明電極等の高抵抗配線電極へのコンタクト或いは四端子法による導電率測定（導電性吸盤自体の抵抗および接触抵抗を無視できる）にしか適用できなかった。
【０００４】
次に、特開平１１−１１１０６４号公報には、回路配線を有する被検査物における電気検査に用いられ、安定して接触が可能な検査用導電ゴムが提案されている。この検査用導電ゴムは、弾性を有する絶縁体中に導電性粒子が含有された導電ゴムシートであって、その表面に微細な凹凸を備えたものである。しかし、導電ゴムシート内に導電性金属粒子を分散させた構成を有するため、導電性、接触抵抗が一定でなく、しかも吸盤状に構成されている訳ではないので、電極に接触させて保持するためには格別の保持手段が必要となり、小型化が困難となり、取扱い上も不便となる。
次に、特開２０００−２１４７０公報には、体積抵抗率が小さく、安定した抵抗値を示し、多くの電流を流すことができ、しかも電極ピッチの小さな基板との低ピッチでの接続が、小さな押圧荷重で実現できる低圧縮低抵抗コネクタが開示されている。導電部材は、絶縁性エラストマ樹脂１００重量部に金属粒子５０〜２００重量部と導電繊維３０〜１５０重量とを配合してなるものであり、これを用いた低圧縮低抵抗コネクタは導電部材からなる導電層と絶縁性エラストマ樹脂からなる絶縁層とが交互に積層してなるものである。
【０００５】
しかし、ここの開示されているコネクタの材料は、金属粒子と導電繊維に絶縁性エラストマ樹脂を混合したものであるが、使用する導電材料の種類が多く、製造手数、コストの点において問題がある。特に、導電繊維だけでは不十分な導通を、金属粒子を混合することにより解消する構成であるため、両材料の配合量のバランスが難しく、導通不良個所も部分的に発生し得る。導通不良個所の発生を防止するためには、導電繊維、金属粒子の配合割合を増やす必要があるが、弾力性を犠牲にする結果をもたらす。また、導電繊維の製造方法、構造が明確でなく、導電繊維間の導通を予め安定して確保し得ることを予定していない点が、コネクタの信頼性を低下させる原因となる。また、ここに開示されたコネクタは、吸盤状に構成することを予定していないので、電極等に取り付ける場合の機械的保持性に問題がある。
【０００６】
【発明が解決しようとする課題】
本発明は上記に鑑みてなされたものであり、電極等の検査対象物に対して脱着容易であり、かつ自己密着機能を有した吸盤構造を備えた導電性部材とすることで、コンタクト時に専用圧接治具を不要にし、しかも接触する電極等にダメージを与えることなく、また３次元構造体を検査対象物とする場合の電極取り出しも容易にすることができる導電性吸盤を提供することを目的とする。
また、本発明の導電性吸盤は、吸盤機能と導電機能を併せ持った一体成形品であるため、小型化が可能でピッチの狭い電極に対しても対応可能となる。
また、本発明の導電性吸盤は、弾性変形して電極等に吸着する吸盤機能を発揮させるために必要な弾力性と、高い導通を発揮するための高導電性を併有することにより、格別の圧接治具などを用いない単純構造且つ小型化を実現できる。即ち、特殊な導電フィラーとゴム状弾性樹脂とを混練することにより、高導電性を持った弾性体を作製することができ、これを吸盤状に成形することで、これまでにない高導電性吸盤による電極コンタクトが可能となった。高導電性であることにより、外力に対しても安定した接触抵抗を確保することができる。
また、ゴム状弾性樹脂に混練する導通フィラー自体が互いに安定した導通を確保する構造であるために、金属粒子等を併用せずに、所望の導通性と、機械的吸着力を備えた導電性吸盤を得ることが可能となる。
【０００７】
【課題を解決するための手段】
上記課題を解決するため、請求項１の発明は、弾性導電体を吸盤状に構成した導電性吸盤において、前記弾性導電体は、少なくとも、ゴム状弾性を有する樹脂と、該ゴム状弾性樹脂に混合される導電性フィラーとを備え、前記導電性フィラーは、前記ゴム状弾性樹脂内において３次元的な網目構造を形成し且つ相互に接触導通することを特徴とする。
弾性導電体を用いて吸盤を形成する場合には、絶縁弾性材料に金属繊維、金属粉を混ぜた弾性導電体を用いるが、導電性と弾性特性との兼ね合いが従来は難しかった。本発明によれば、このような二率背反の関係にある２つの特性をバランスよく調整して、吸着対象となる電極等との間の接触抵抗が低く、自己密着機能を有する導電性部材を得ることができる。即ち、ゴム状弾性を有する樹脂と、３次元的な網目構造を形成し相互に接触導通する導電性フィラーとを少なくとも含んだ弾性導電体は、導導電性と低弾性特性を兼ね備え、吸盤状に形成することで容易に脱着可能な電極端子との導通を確保できる導通部材である。導電性フィラー自体が針状であり、且つ互いに高い導電性を得ることができるように網目状に連結している構造であるため、金属粉等を添加する等の煩雑な手順を経ることなく、低コストで材料を製作することができ、しかも加工性を良好に維持することができる。
請求項２の発明は、前記導電性フィラーは、ウイスカーから成るコア材と、該コア材の表層に被覆される導電皮膜とから成り、前記導電被膜は、Ａｕ、Ａｇ、Ｎｉ、又はＳｎのうちの何れか一種類の金属、或いはこれらのうちの少なくとも２種類を含む合金から成ることを特徴とする。
３次元的な網目構造を形成し相互に接触導通する導電性フィラーのコア材としてウイスカーを用い、コア材の表層にＡｕ、Ａｇ、Ｎｉ、Ｓｎ或いはそれらを含む合金にて被覆したので、径が小さく高アスペクト比の導電フィラーを容易に製作でき、導電性吸盤に必要な弾性特性および接触抵抗特性の両立が可能となる。コア材がウィスカーであり、３次元的な網目構造を形成し易い上に、その表面に接触抵抗の低い材料を被覆しているので、導電フィラーとして最適である。
【０００８】
請求項３の発明は、前記導電性フィラーのコア材が、アルミ陽極酸化膜の微細孔内に金属を充填してからアルミ陽極酸化膜を除去することにより形成されていることを特徴とする。
ウィスカー状のコア材を形成する方法として、このような製法を採用するため、３次元的な網目構造を形成し且つ相互に接触導通しやすい針形状導電フィラーを簡易に形成することができる。即ち、３次元的な網目構造を形成し且つ相互に接触導通する導電性フィラーのコア材をアルミ陽極酸化膜の微細孔に金属を埋め込んで形成することで、径が小さく高アスペクト比の金属針状フィラーを容易に製作できる。金属針状フィラーは、３次元的な屈曲にも強いため網目構造を形成した接触導通性能が向上できるとともに、フィラー抵抗値の低減も可能であり、導電性吸盤に必要な弾性特性および接触抵抗特性の両立を実現できる。
請求項４の発明は、前記ゴム状弾性樹脂が、紫外線硬化性及び湿気硬化性を併せ持ったシリコーン樹脂であることを特徴とする。
上記の如き弾性導電体を用いて所望の寸法、形状を有した吸盤を製造する際に、複雑な型を用いたり、時間を要する工程を経る場合には、生産性の低下、精度低下を招く虞がある。これに対し、本発明では、ゴム状弾性樹脂が、紫外線硬化性、湿気硬化性を有しているので、導電性吸盤を製造するに当たり、加熱を必要とせず短時間で製作できる紫外線照射を行うので、ゴム状弾性樹脂の硬化時間を短縮して生産性を高めることができる。
請求項５の発明は、請求項１乃至４に記載において、前記導電性吸盤の裏面に、半田付け可能な金属箔を配置したことを特徴とする。
これによれば、導電性吸盤を半田付け可能な導通部材とし、後付け部品として任意の端子における電極取り出しを容易にすることができる。即ち、半田付け可能な金属箔上に導電性吸盤を形成したことにより、導電性吸盤を一つの導通部品として後付けが可能となるため、直接導電性吸盤を電極端子に形成することが困難な３次元構造体に対しても容易に形成可能となる。
【０００９】
請求項６の発明に係る導電性吸盤シートは、請求項１乃至４の何れか一項に記載の導電性吸盤を複数個、弾性導電体から成るシート面上にマトリックス状に一体化配置したことを特徴とする。
これによれば、シート状の弾性導電体上にマトリックス状に導電性吸盤を一体形成しているため、隣接する電極パターン間の短絡を電極にダメージを与えることなく脱着容易に実施できる。つまり、隣接する電極パターン間の導通を容易にできる導電シートを得ることができる。
請求項７の発明に係る導電性吸盤シートは、前記導電性吸盤間に位置する弾性導電体表面の少なくとも一部に絶縁層を設けたことを特徴とする。
これによれば、マトリックス状に導電性吸盤を配置したシートの、表面の少なくとも一部に絶縁部を設けたことで、吸盤部を密着させた任意の電極端子のみを短絡することができる。
請求項８の発明に係るフレキシブル配線板は、請求項１乃至４に記載の導電性吸盤を、フレキシブル配線板の電極端子上に配置したことを特徴とする。
ＦＰＣの電極端子上に導電性吸盤を形成することにより、任意の電極端子の短絡が容易にできるとともに短絡抵抗の低減も可能となる。
請求項９の発明は、フレキシブル配線板の電極端子上に請求項１乃至４に記載の導電性吸盤を配置する方法であって、フレキシブル板の電極端子上、或いは吸盤形成ツール先端に、紫外線硬化性シリコーン樹脂と３次元的な網目構造を形成し相互に接触導通する導電性フィラーとを含む導電性ペーストを供給後、電極端子上に前記吸盤形成ツールをギャップ管理した状態で押し付けた後紫外線照射することにより導電性吸盤を形成することを特徴とする。
ＦＰＣの電極端子上に導電性吸盤を形成するに際して、紫外線硬化性シリコーン樹脂と３次元的な網目構造を形成し且つ相互に接触導通する導電性フィラーとを含むペーストを供給した後、端子上にツールを押しつけながら紫外線照射することにより導電性吸盤を形成するようにした。このため、専用型を不要とするとともに、製造コストの低減を図ることが出来る電極端子上への導電性吸盤形成方法を実現できる。
請求項１０の発明に係る端子引き出し用電線は、電線の先端に、請求項１乃至４に記載の導電性吸盤を電気的機械的に固定したことを特徴とする。
電線を構成する導体の先端に導電性吸盤を形成したことにより、基板側に設けた電極端子に対して脱着式で電線による電極引出しが可能となる。このため、導通検査用として任意の端子から電極を引き出すことが可能な電線を提供することができる。
【００１０】
【発明の実施の形態】
以下、本発明を添付図面に示した実施の形態に基づいて詳細に説明する。
図１（ａ）及び（ｂ）は夫々本発明の一実施形態に係る導電性吸盤の構成を示す断面図、及びコンタクト状態を示す図である。
この導電性吸盤１は、弾性導電体を図１（ａ）に示すような吸盤状に成形したものである。ここで吸盤とは、支持部２からテーパー状（スカート状）に拡開する形状を有した吸盤本体３の形状を指称し、図１（ｂ）に示すように電極１２の面等に吸盤本体３の開放側を圧接することにより、圧縮方向へ弾性変形しつつ吸盤本体３と電極面との間で形成される閉空間内の空気を排出して負圧状態にして吸着力を得る構造を云う。
図１の実施形態にかかる導電性吸盤１を構成する弾性導電体は、後述するように最適な弾性率を有していることから、吸盤本体３を、基板１１上の電極１２の面に押し付けることにより十分な吸盤特性を得ることができ、平面状の電極のみならず、曲面状の電極に対しても安定した密着性が得られ、平面同様の接触抵抗を得ることができる。また、吸盤方式での接触のため、電極１２にダメージを与えることなくコンタクトを取ることができる。
【００１１】
また、図２（ａ）及び（ｂ）は他の実施形態に係る導電性吸盤の構成図であり、この導電性吸盤１は、弾性導電体をシート状に加工した導電性吸盤シート５の片面に円弧状の凹所６を形成することによって、凹所６の底部に薄肉変形部７を形成し、凹所６の開放側を電極１２の面に圧接させてから薄肉変形部７を圧縮変形させることによって電極面に吸着保持させる構成を備えている。
図２の実施形態にかかる導電性吸盤１を構成する弾性導電体（導電性吸盤シート５）の導電性吸盤１は、後述するように最適な弾性率を有していることから、導電性吸盤シート５の下面に位置する凹所６を、基板１１上の電極１２の面に押し付けることにより十分な吸盤特性を得ることができ、平面状の電極のみならず、曲面状の電極に対しても安定した密着性が得られ、平面同様の接触抵抗を得ることができる。また、吸盤方式での接触のため、電極１２にダメージを与えることなくコンタクトを取ることができる。
本発明の弾性導電体は、図３の拡大断面図に示すように、例えばゴム状弾性樹脂１５の代表格であるシリコーン樹脂に、３次元的な網目構造を形成し且つ相互に接触導通可能な針形状導電フィラー２０を含有させた構成を備えている。
ゴム状弾性樹脂１５としては、ゴム硬度（ＪＩＳ　Ａ）２８のシリコーン樹脂を使用した。また、導電性フィラー２０は、ウイスカーから成るコア材と、該コア材の表層に被覆される導電皮膜とから構成され、導電被膜は、Ａｕ、Ａｇ、Ｎｉ、又はＳｎのうちの何れか一種類の金属、或いはこれらのうちの少なくとも２種類を含む合金から成る。本実施形態では、例えば導電フィラー２０としては無機化合物ウイスカーにＡｇめっきを施したものを使用し、フィラー径約０．５μｍ、フィラー長約２０μｍのものを使用した。
このような弾性導電体の体積抵抗率及びゴム硬度（ＪＩＳ　Ａ）を図４（ａ）及び（ｂ）に示す。まず、体積抵抗率については、図４（ａ）に示した如くフレーク状フィラーを用いた弾性導電体にあっては、針形状導電フィラー２０を用いた弾性導電体に比して、体積抵抗率が高くなる。このため、本発明の弾性導電体の方が高い導電性を有することが明らかである。また、ゴム硬度については、図４（ｂ）に示した如く、針形状導電フィラー２０の方が、フレーク状フィラーを用いた弾性導電体に比してゴム硬度が明らかに低くなっており、本発明の弾性導電体の方が吸盤としての吸着保持力が強くなることが明らかである。しかも、本発明の弾性導電体にあっては、針形状導電フィラー２０の配合量を増大させたとしても、フレーク状フィラーを含有した弾性導電体の硬度を遙かに下回る低い硬度となるに過ぎない。
【００１２】
次に、導電性吸盤としての評価結果を図５に示す。
ここでは、ゴム状弾性樹脂１５に対する、針形状導電フィラー２０の配合比を４０ｗｔ％から７０ｗｔ％まで４段階に分けた場合における、接触抵抗と、吸盤による保持時間を評価した。
この結果、針形状導電フィラーの配合比を５０ｗｔ％、６０ｗｔ％とした場合に、接触抵抗が低くなって導電性が高くなり、しかも十分な吸着力を維持し得ることが判明した。
次に、３次元的な網目構造を形成し、相互に接触導通しうる導電フィラー２０は、ウイスカーから成るコア材と、該コア材の表層に被覆される導電皮膜とから構成されるが、コア材は、例えばアルミ陽極酸化膜の微細孔内に、Ｎｉ電解めっきにてニッケルを埋め込み、アルミ陽極酸化膜を溶解して除去することによって形成される。ここでは、導電フィラーコア材として径：０．１μｍφ、長さ：３０μｍのＮｉフィラーを製作した。導電フィラーコア材の表層に、Ａｕ、Ａｇめっきを施すと接触抵抗を低減することができる。針形状の金属フィラー２０は、折れ曲がり特性に優れているため、３次元的な網目構造による相互接触を更に形成しやすい特性を持っている。
次に、本発明の他の実施形態に係る導電性吸盤にあっては、ゴム状弾性樹脂１５が、紫外線硬化性及び湿気硬化性を併せ持ったシリコーン樹脂である点が特徴的である。
即ち、まず本発明の導電性吸盤１を構成する弾性導電体は、図４（ａ）から分かるように導電性フィラー２０の含有量を少なくしても高導電性が得られることと、フィラー形状が針形状をしていることからフレーク状フィラーを含有した弾性導電体よりも光が内層まで入り込むことが特徴的である。
ゴム状弾性樹脂１５として紫外線硬化性及び湿気硬化性を併せ持ったシリコーン樹脂（例えばスリーボンド製３１６４）に対して針形状導電フィラーを混練した弾性導電体を所要形状に成形した状態で紫外線を照射すると、紫外線を照射することで内部まで完全硬化することも可能であるが、表層近傍のみを硬化させた後で、常温常湿環境での保管による湿気硬化機能を活用して完全硬化に至らせることもできる。この方法では、少なくとも弾性導電体の表層近傍の完全硬化を短時間で完了することができるとともに、加熱を必要としないため、加熱できない電子部品への導電性吸盤形成が可能となる。
【００１３】
次に、図６は本発明の一実施形態に係る導電性吸盤シートの構成を示す断面図である。
この実施形態に係る導電性弾性シート５は、弾性導電体から成るシート部の下面に、導電性吸盤１を複数個、マトリックス状に配置したものである。
マトリックス状に吸盤１を設けたことで、図２に示した基板１１上に設けた電極１２のうち、隣接する任意の電極１２を吸盤１にて吸着させることにより、電極間を短絡させることが可能となる。たとえば、薄膜で形成されたデバイスの電極パターンをまたがるように導電性吸盤シートを接触させることにより、薄膜にダメージを与えることなく低抵抗で短絡することができ、不良解析等を簡便に行うことができる。
次に、図７は本発明の他の実施形態に係る導電性吸盤シートの構成を示す斜視図である。この実施形態に係る導電性吸盤シート５は、弾性導電体シート下面に凹所６を露出させる各吸盤１の部分を除いた、弾性導電体シート下面の一部、又は全部を絶縁部（絶縁層）２５としている。
図２に示した如く、複数の電極１２を備えた基板１１において、任意の電極１２のみを短絡するためには、導電性吸盤シート５の吸盤１以外の部位（下面）が基板１１の他の部位に接触した時に絶縁性を確保するように構成する必要がある。このため、導電性吸盤シートの吸盤１を除いた下面部分に絶縁層２５を形成し、電極１２に吸着した吸盤部１でのみ電極と導通が図れるようにしている。
この場合、複数配列された電極１２の内の任意の電極に対してのみ吸盤１が吸着するように吸盤を配置する一方で、吸盤以外の基板下面については絶縁層２５により絶縁被覆すればよい。
【００１４】
図８（ａ）（ｂ）及び（ｃ）は、本発明の他の実施形態に係る導電性吸盤の構成を示す斜視図、Ａ−Ａ断面図、及び適用例を示す断面図である。
この実施形態に係る導電性吸盤１を構成する弾性導電体は、図３に示した如く例えばゴム状弾性樹脂１５の代表格であるシリコーン樹脂に、３次元的な網目構造を形成し且つ相互に接触導通可能な針形状導電フィラー２０を含有させた構成を備えている。この導電性吸盤１は、弾性導電体から成る吸盤本体３と、吸盤本体３のフラットな底面（薄肉変形部）３ａに固定された金属箔３０と、を備えている。吸盤本体３に金属箔３０を固定した理由は、半田や導電性接着剤等のバインダを用いた接着を可能にするためである。従って、使用する金属箔３０は、半田や導電性接着剤となじみのよい材質を選定する。例えば、この金属箔３０はＣｕ箔のみでも良いが、吸盤本体３との接触抵抗を低減するため、表層にＡｕ、Ａｇめっきを施すことが好ましい。この金属箔付き導電性吸盤１は、直接導電性吸盤を電極に固定することが困難な３次元構造体に対しても、一つの導通部品として後付けが可能である。また、図８（ｃ）に示すようにコンタクトプローブ３１の先端に半田３２等によって後付けで固定すれば、コンタクトプローブ３１は保持機構無しに電極との導通を確保することができるようになる。ここで導電性吸盤１をコンタクトプローブ先端に後付けする方法としては、半田付けおよび導電性接着剤等のバインダ３２による接合等が可能である。
仮に、金属箔を有しない導電性吸盤を電極に固定するに場合には、半田付けができないほか、弾性樹脂の接着濡れ性が悪いことから導電性接着剤による接着接合においても十分な強度が確保できていなかったが、金属箔をつけることでこれら問題を解決することができる。
【００１５】
次に、図９は本発明の他の実施形態に係る導電性吸盤の適用例であり、この例ではフレキシブル配線板５０（ＦＰＣ）の電極端子５１上に導電性吸盤１を形成している。
導電性吸盤１をＦＰＣ５０上に形成することにより、配線部の低抵抗化が可能となり接触抵抗を含めた電極端子間を短絡したときの電気抵抗を低くすることができる。また、屈曲性の高いＦＰＣ５０であることから、３次元構造体の異なる電極面間の導通に対しても良好な吸盤密着特性と接触抵抗特性を確保することができる。
次に、図１０（ａ）及び（ｂ）は、図９に示した導電性吸盤付きＦＰＣ５０の製造手順を示す図である。
ＦＰＣ５０の電極端子５１上への導電性吸盤１の形成方法は、次の如くである。即ち、まず、図１０（ａ）のように、紫外線硬化性シリコーン樹脂１５（図３）と、３次元的な網目構造を形成し相互に接触導通する導電性フィラー２０（図３）とを混練した導電性ペースト５５をＦＰＣ電極端子５１上、或いは凸形状を持った吸盤形成ツール５６に供給する。図示の例では、導電性ペースト５５をＦＰＣ電極端子５１上に供給している。導電性ペースト５５の供給方法は、スクリーン印刷、ディスペンス、転写等の工法により行うことができる。その後、電極端子５１上にギャップ管理した状態で吸盤形成ツール５６を押しつけながら紫外線照射することにより、ＦＰＣ電極端子上に凹形状の導電性吸盤を形成することができる。ここで、吸盤形成用ツール５６としては、表面エネルギーの小さな材料を用いるか、或いは表面処理が施されていることが必要である。
次に、図１１（ａ）及び（ｂ）は本発明の他の実施形態に係る導電性吸盤の構成を示す断面図、及び適用例を示す図である。
この実施形態に係る導電性吸盤１は、電線６０の先端に導電性吸盤１を電気的機械的に接続した構成を有している。
所定の電極端子１２から電気信号を取り出そうとする場合等、電線６０の先端に導電性吸盤１を形成しておけば、吸盤部でのコンタクトに加え、電線部をクランプすることで、電気信号の取出しが可能となる。また個々の電線部を半田付け等しておけば任意の電極端子間を短絡しながら電気信号を取り出すことも可能となる。
【００１６】
【発明の効果】
以上のように本発明によれば、電極等の検査対象物に対して機械的に固定したり取り外す操作が容易であり、かつ高い導通を確保できる吸盤構造を備えた導電性部材とすることで、コンタクト時に専用圧接治具を不要にし、しかも接触する電極等にダメージを与えることなく、また３次元構造体を検査対象物とする場合の電極取り出しも容易にすることができる。吸盤機能と導電機能を併せ持った一体成形品とすることにより、小型化が可能でピッチの狭い電極に対しても対応可能となる。また、弾性変形して電極等に吸着する吸盤機能を発揮させるために必要な弾力性と、高い導通を発揮するための高導電性を併有することにより、格別の圧接治具などを用いない単純構造且つ小型化を実現できる。また、ゴム状弾性樹脂に混練する導通フィラー自体が互いに安定した導通を確保する構造であるために、金属粒子等を併用せずに、所望の導通性と、機械的吸着力を備えた導電性吸盤を得ることが可能となる。
即ち、請求項１の発明によれば、ゴム状弾性を有する樹脂と、３次元的な網目構造を形成し相互に接触導通する導電性フィラーとを少なくとも含んだ弾性導電体を用いるので、導導電性と低弾性特性を兼ね備え、吸盤状に形成することで容易に脱着可能な電極端子との導通を確保できる。また、導電性フィラー自体が針状であり、且つ互いに高い導電性を得ることができるように網目状に連結し易い構造であるため、金属粉等を添加する等の煩雑な手順を経ることなく、低コストで材料を製作することができ、しかも加工性を良好に維持することができる。
請求項２の発明によれば、径が小さく高アスペクト比の導電フィラーを容易に製作でき、導電性吸盤に必要な弾性特性および接触抵抗特性の両立が可能となる。
請求項３の発明によれば、ウィスカー状のコア材を形成する方法として、このような製法を採用するため、３次元的な網目構造を形成し且つ相互に接触導通しやすい針形状導電フィラーを簡易に形成することができる。
請求項４の発明によれば、ゴム状弾性樹脂が、紫外線硬化性、湿気硬化性を有しているので、導電性吸盤を製造するに当たり、加熱を必要とせず短時間で製作できる紫外線照射を行うので、ゴム状弾性樹脂の硬化時間を短縮して生産性を高めることができる。
【００１７】
請求項５の発明によれば、導電性吸盤を半田付け可能な導通部材とし、後付け部品として任意の端子における電極取り出しを容易にすることができる。
請求項６の発明に係る導電性吸盤シートによれば、シート状の弾性導電体上にマトリックス状に導電性吸盤を一体形成しているため、隣接する電極パターン間の短絡を電極にダメージを与えることなく脱着容易に実施できる。
請求項７の発明に係る導電性吸盤シートによれば、マトリックス状に導電性吸盤を配置したシートの、表面の少なくとも一部に絶縁部を設けたことで、吸盤部を密着させた任意の電極端子のみを短絡することができる。
請求項８の発明に係るフレキシブル配線板によれば、ＦＰＣの電極端子上に導電性吸盤を形成することにより、任意の電極端子の短絡が容易にできるとともに短絡抵抗の低減も可能となる。
請求項９の発明によれば、専用型を不要とするとともに、製造コストの低減を図ることが出来る電極端子上への導電性吸盤形成方法を実現できる。
請求項１０の発明に係る端子引き出し用電線によれば、電線を構成する導体の先端に導電性吸盤を形成したことにより、基板側に設けた電極端子に対して脱着式で電線による電極引出しが可能となる。
【図面の簡単な説明】
【図１】（ａ）及び（ｂ）は夫々本発明の一実施形態に係る導電性吸盤の構成を示す断面図、及びコンタクト状態を示す図。
【図２】（ａ）及び（ｂ）は本発明の他の実施形態に係る導電性吸盤の構成図。
【図３】本発明の弾性導電体の一例の構成を示す拡大断面図。
【図４】（ａ）及び（ｂ）は夫々本発明の弾性導電樹脂の体積抵抗率、及び弾性特性を示す図。
【図５】本発明の導電性吸盤の評価結果を示す図。
【図６】本発明の一実施形態に係る導電性吸盤シートの構成を示す断面図。
【図７】本発明の他の実施形態に係る導電性吸盤シートの構成を示す斜視図。
【図８】（ａ）（ｂ）及び（ｃ）は、本発明の他の実施形態に係る導電性吸盤の構成を示す斜視図、Ａ−Ａ断面図、及び適用例を示す断面図。
【図９】本発明の他の実施形態に係る導電性吸盤の適用例を示す図。
【図１０】（ａ）及び（ｂ）は、図９に示した導電性吸盤付きＦＰＣ５０の製造手順を示す図。
【図１１】（ａ）及び（ｂ）は本発明の他の実施形態に係る導電性吸盤の構成を示す断面図、及び適用例を示す図。
【符号の説明】
１　導電性吸盤、２　支持部、３　吸盤本体、３ａ　底面（薄肉変形部）、５導電性吸盤シート、６　凹所、７　薄肉変形部、１１　基板、１２　電極（電極端子）、１５　ゴム状弾性樹脂、２０　針形状導電フィラー、２５　絶縁部（絶縁層）、３０　金属箔、３１　コンタクトプローブ、３２　バインダ、５０　フレキシブル配線板（ＦＰＣ）、５１　電極端子、５５　導電性ペースト。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the improvement of a conductive sucker as a mechanical contact type conductive member, and in particular, while having a strong sucker function by elastic deformation, a conductive sucker capable of exhibiting a high conductive function, a conductive sucker sheet, The present invention relates to a flexible wiring board, a method for manufacturing the same, and an electric wire for leading out a terminal.
[0002]
[Prior art]
In a continuity test and an insulation test for an inspection object provided with electrodes, terminals, contacts, and the like that constitute circuit wiring, a method of contacting a mechanical contact-type conductive member to an electrode or the like and energizing the electrode has been conventionally used. I have. As such a mechanical contact type conductive member, various types of connectors, such as a contact probe pin or a connector obtained by mixing a conductive filler in a rubber-like elastic resin, have been developed. However, conventional mechanical contact type conductive members require a dedicated jig for ensuring mechanical contact with the electrodes and the like, in addition to means for securing electrical conduction between the electrodes and the like. For this reason, in addition to the disadvantages of an increase in the number of parts, an increase in size due to the complexity of the structure, and an increase in cost, when a conventional conductive member is applied to a three-dimensional structure unit having electrodes on a plurality of surfaces, an increase in electrode There is a disadvantage that it is difficult to make electrical contact.
As such a conventional example, Japanese Patent Application Laid-Open No. 2002-25669 discloses an invention relating to a sucker electrode in which a sucker function and a conductive function are separated. This publication discloses a configuration in which a separate electrode is disposed inside a suction cup made of an insulating elastic material such as rubber and resin.However, when the suction cup function and the conductive function are separated as described above, In addition, an increase in the number of parts and an increase in the complexity of the structure are unavoidable, so that downsizing is difficult and there is a problem that it is impossible to cope with a case where the pitch between electrodes as an object to be suctioned is narrow.
Further, Japanese Utility Model Registration No. 2532597 discloses a metal suction cup for measuring physical conditions such as a fat tissue amount by adsorbing electricity on the body surface and applying a current thereto. Is not elastically deformed, it is necessary to operate the hollow suction member connected to the opposite side of the suction cup to make the inside of the suction cup a negative pressure in order to adsorb to the body surface. Therefore, miniaturization is impossible, and if the object to be adsorbed is a surface having flexibility and elasticity, such as the surface of a body, it is easy to adsorb, but flexibility such as a metal electrode or the like is obtained. There is a disadvantage that the method cannot be applied to a surface which does not have the surface, or a surface having irregularities on the electrode surface or its periphery.
[0003]
In order to solve such a problem, there has been conventionally proposed a conductive suction cup in which a suction cup made of an elastic material is made conductive so as to simultaneously secure adsorption and conduction to an electrode. A conductive sucker in which the sucker function and the conductive function are integrated is disclosed in, for example, Japanese Utility Model Laid-Open No. 61-60472. However, it has been difficult for conventional conductive suction cups to achieve both elasticity for exhibiting the suction cup function and high conductivity. That is, the conductive rubber (conductive resin) obtained by kneading the conductive filler into the conventional rubber-like elastic resin has low conductivity and unstable contact resistance. However, there is a disadvantage that the conductivity must be sacrificed by reducing the amount of the conductive filler, while the adsorption force must be sacrificed when the conductivity is increased by increasing the amount of the conductive filler. For this reason, the above-mentioned conventional conductive suction cup can be applied only to the contact with a high-resistance wiring electrode such as a transparent electrode or the conductivity measurement by the four-terminal method (the resistance and contact resistance of the conductive suction cup itself can be ignored). .
[0004]
Next, Japanese Unexamined Patent Application Publication No. 11-111064 proposes a conductive rubber for inspection which is used for an electrical inspection of an inspection object having circuit wiring and can be stably contacted. The conductive rubber for inspection is a conductive rubber sheet in which conductive particles are contained in an insulator having elasticity, and has fine irregularities on its surface. However, since it has a configuration in which conductive metal particles are dispersed in a conductive rubber sheet, the conductivity and contact resistance are not constant, and it is not necessarily configured in a suction cup shape, so that it is held in contact with an electrode. For this purpose, special holding means is required, miniaturization becomes difficult, and handling becomes inconvenient.
Next, Japanese Patent Application Laid-Open No. 2000-21470 discloses that a low volume resistivity, a stable resistance value, a large amount of current can flow, and a low-pitch connection with a substrate having a small electrode pitch is small. A low compression low resistance connector that can be realized by a pressing load is disclosed. The conductive member is obtained by blending 50 to 200 parts by weight of metal particles and 30 to 150 parts by weight of conductive fibers with 100 parts by weight of an insulating elastomer resin, and a low-compression low-resistance connector using the same is made of a conductive member. The conductive layer and the insulating layer made of an insulating elastomer resin are alternately laminated.
[0005]
However, the material of the connector disclosed herein is a mixture of metal particles and conductive fibers with an insulating elastomer resin. However, there are many types of conductive materials to be used, and there is a problem in the number of manufacturing steps and cost. . In particular, since the configuration is such that the insufficient conduction by the conductive fiber alone is eliminated by mixing the metal particles, it is difficult to balance the blending amounts of the two materials, and a conduction failure portion may partially occur. It is necessary to increase the mixing ratio of the conductive fiber and the metal particles in order to prevent the occurrence of the conduction failure portion, but this results in sacrificing elasticity. In addition, the method and structure of the conductive fiber are not clear, and it is not planned to stably secure the conduction between the conductive fibers in advance, which causes a reduction in the reliability of the connector. Further, since the connector disclosed herein is not intended to be formed in a suction cup shape, there is a problem in mechanical holding properties when the connector is attached to an electrode or the like.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above, and is a conductive member having a suction cup structure that is easily detachable from an inspection object such as an electrode and has a self-adhesion function, so that it is exclusively used at the time of contact. An object of the present invention is to provide a conductive suction cup which does not require a pressure welding jig, does not damage electrodes and the like which are in contact with each other, and can easily take out electrodes when a three-dimensional structure is to be inspected. And
Further, since the conductive suction cup of the present invention is an integrally molded product having both a suction cup function and a conductive function, it can be downsized and can be applied to an electrode having a narrow pitch.
In addition, the conductive suction cup of the present invention has an elasticity required for exhibiting a suction cup function of elastically deforming and adsorbing to an electrode or the like, and having high conductivity for exhibiting high conduction, which is exceptional. A simple structure and miniaturization without using a pressure welding jig or the like can be realized. That is, by kneading a special conductive filler and a rubber-like elastic resin, it is possible to produce an elastic body having high conductivity, and by molding this into a suction cup shape, an unprecedented high conductivity is obtained. Electrode contact with a suction cup has become possible. Due to the high conductivity, a stable contact resistance can be ensured even with an external force.
In addition, since the conductive filler itself kneaded into the rubber-like elastic resin has a structure that ensures stable conduction with each other, the conductive filler having a desired conductivity and a mechanical attraction force without using metal particles or the like in combination. It becomes possible to obtain a suction cup.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a conductive sucker in which an elastic conductor is formed in a sucker shape, wherein the elastic conductor includes at least a resin having rubber-like elasticity and the rubber-like elastic resin. And a conductive filler to be mixed, wherein the conductive filler forms a three-dimensional network structure in the rubber-like elastic resin and is in contact with and conductive to each other.
When a suction cup is formed using an elastic conductor, an elastic conductor in which metal fibers and metal powder are mixed with an insulating elastic material is used. However, it has been conventionally difficult to achieve a balance between conductivity and elastic characteristics. According to the present invention, a conductive member having a self-adhesion function with a low contact resistance with an electrode or the like to be adsorbed is adjusted in a well-balanced manner by adjusting the two characteristics in a two-way conflict. Obtainable. That is, the elastic conductor including at least a resin having rubber-like elasticity and a conductive filler which forms a three-dimensional network structure and makes contact and conduct with each other has both conductivity and low elasticity, and has a suction cup shape. It is a conducting member that can secure conduction with an electrode terminal that can be easily detached by being formed. Since the conductive filler itself is acicular, and has a structure in which the conductive fillers are connected in a mesh shape so that high conductivity can be obtained, without going through complicated procedures such as adding metal powder, etc. The material can be manufactured at low cost, and good workability can be maintained.
The invention according to claim 2 is that the conductive filler comprises a core material made of whiskers and a conductive film coated on a surface layer of the core material, wherein the conductive film is made of Au, Ag, Ni, or Sn. , Or an alloy containing at least two of these metals.
A whisker is used as a core material of a conductive filler that forms a three-dimensional network structure and is in contact with each other, and is covered with Au, Ag, Ni, Sn or an alloy containing them, so that the diameter of the core material is reduced. A conductive filler having a small and high aspect ratio can be easily manufactured, and it is possible to achieve both elastic properties and contact resistance properties required for a conductive suction cup. The core material is a whisker, which easily forms a three-dimensional network structure, and its surface is coated with a material having low contact resistance, so that it is optimal as a conductive filler.
[0008]
The invention according to claim 3 is characterized in that the core material of the conductive filler is formed by filling a metal into micropores of the aluminum anodic oxide film and then removing the aluminum anodic oxide film.
Since such a manufacturing method is employed as a method of forming a whisker-shaped core material, a three-dimensional network structure can be formed, and a needle-shaped conductive filler that is easily brought into contact with each other can be easily formed. That is, a metal needle having a small diameter and a high aspect ratio is formed by embedding a metal in a fine hole of an aluminum anodic oxide film to form a core material of a conductive filler which forms a three-dimensional network structure and is in contact with each other. Filler can be easily manufactured. The metal needle-shaped filler is resistant to three-dimensional bending, so that it can improve the contact conduction performance with a network structure and also reduce the filler resistance value, making it possible to provide the elastic and contact resistance properties required for conductive suction cups. Can be achieved.
The invention according to claim 4 is characterized in that the rubbery elastic resin is a silicone resin having both ultraviolet curability and moisture curability.
When manufacturing a suction cup having a desired size and shape using the elastic conductor as described above, when a complicated mold is used or when a time-consuming process is performed, a decrease in productivity and a decrease in accuracy are caused. There is a fear. On the other hand, in the present invention, since the rubber-like elastic resin has ultraviolet curability and moisture curability, in producing a conductive suction cup, ultraviolet irradiation that can be manufactured in a short time without heating is performed. Therefore, it is possible to shorten the curing time of the rubber-like elastic resin and increase the productivity.
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a metal foil that can be soldered is disposed on a back surface of the conductive suction cup.
According to this, the conductive sucker is a conductive member that can be soldered, and it is possible to easily take out an electrode from an arbitrary terminal as a post-installed component. That is, since the conductive suction cup is formed on a metal foil that can be soldered, the conductive suction cup can be retrofitted as one conductive component, and it is difficult to directly form the conductive suction cup on the electrode terminal. It can be easily formed on a three-dimensional structure.
[0009]
According to a sixth aspect of the present invention, there is provided a conductive sucker sheet, wherein a plurality of the conductive suckers according to any one of the first to fourth aspects are integrally arranged in a matrix on a sheet surface made of an elastic conductor. It is characterized.
According to this, since the conductive suction cups are integrally formed in a matrix on the sheet-like elastic conductor, a short circuit between adjacent electrode patterns can be easily performed without damaging the electrodes. That is, it is possible to obtain a conductive sheet that can facilitate conduction between adjacent electrode patterns.
The conductive suction cup sheet according to the invention of claim 7 is characterized in that an insulating layer is provided on at least a part of the surface of the elastic conductor located between the conductive suction cups.
According to this, by providing an insulating portion on at least a part of the surface of the sheet on which the conductive suction cups are arranged in a matrix, it is possible to short-circuit only any of the electrode terminals to which the suction cups are adhered.
An eighth aspect of the present invention provides a flexible wiring board, wherein the conductive suction cup according to any one of the first to fourth aspects is arranged on an electrode terminal of the flexible wiring board.
By forming a conductive suction cup on the electrode terminal of the FPC, it is possible to easily short-circuit an arbitrary electrode terminal and to reduce short-circuit resistance.
According to a ninth aspect of the present invention, there is provided a method for arranging the conductive suction cup according to any one of the first to fourth aspects on the electrode terminal of the flexible wiring board. After supplying a conductive paste containing a conductive silicone resin and a conductive filler that forms a three-dimensional network structure and makes contact and conduct with each other, presses the suction cup forming tool on an electrode terminal in a state where a gap is controlled, and then irradiates ultraviolet rays. In this case, a conductive sucker is formed.
When forming a conductive suction cup on the electrode terminal of the FPC, after supplying a paste containing an ultraviolet-curing silicone resin and a conductive filler that forms a three-dimensional network structure and makes contact with each other, is supplied onto the terminal. The conductive suction cup was formed by irradiating ultraviolet rays while pressing the tool. For this reason, a method for forming a conductive suction cup on an electrode terminal can be realized in which a dedicated mold is not required and the manufacturing cost can be reduced.
According to a tenth aspect of the present invention, there is provided an electric wire for terminal withdrawal, wherein the conductive suction cup according to any one of the first to fourth aspects is electrically and mechanically fixed to an end of the electric wire.
By forming the conductive suction cup at the end of the conductor constituting the electric wire, it is possible to detach the electrode terminal provided on the substrate side and to draw out the electrode by the electric wire. For this reason, it is possible to provide an electric wire from which an electrode can be drawn out from any terminal for continuity inspection.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
1A and 1B are a cross-sectional view illustrating a configuration of a conductive suction cup according to an embodiment of the present invention, and a view illustrating a contact state, respectively.
The conductive suction cup 1 is formed by molding an elastic conductor into a suction cup shape as shown in FIG. Here, the suction cup refers to the shape of the suction cup main body 3 having a shape that expands in a tapered shape (skirt shape) from the support portion 2, and as shown in FIG. 3 is pressed against the open side to discharge the air in the closed space formed between the suction cup body 3 and the electrode surface while elastically deforming in the compression direction, thereby obtaining a negative pressure state to obtain a suction force. say.
Since the elastic conductor constituting the conductive suction cup 1 according to the embodiment of FIG. 1 has an optimum elastic modulus as described later, the suction cup main body 3 is pressed against the surface of the electrode 12 on the substrate 11. As a result, sufficient suction characteristics can be obtained, stable adhesiveness can be obtained not only to a flat electrode but also to a curved electrode, and a contact resistance similar to a flat surface can be obtained. Further, since the contact is made by the suction cup method, the contact can be made without damaging the electrode 12.
[0011]
FIGS. 2A and 2B are configuration diagrams of a conductive suction cup according to another embodiment. This conductive suction cup 1 has a single-sided surface of a conductive suction cup sheet 5 obtained by processing an elastic conductor into a sheet shape. By forming an arc-shaped recess 6 in the bottom, a thin deformed portion 7 is formed at the bottom of the recess 6, and the open side of the recess 6 is pressed against the surface of the electrode 12, and then the thin deformed portion 7 is compressed and deformed. Then, a configuration is provided in which the electrode surface is held by suction.
Since the conductive suction cup 1 of the elastic conductor (conductive suction sheet 5) constituting the conductive suction cup 1 according to the embodiment of FIG. 2 has an optimum elastic modulus as described later, the conductive suction cup is used. By pressing the recess 6 located on the lower surface of the sheet 5 against the surface of the electrode 12 on the substrate 11, sufficient suction characteristics can be obtained, and not only for a flat electrode but also for a curved electrode. Stable adhesion can be obtained, and a contact resistance similar to a flat surface can be obtained. Further, since the contact is made by the suction cup method, the contact can be made without damaging the electrode 12.
As shown in the enlarged cross-sectional view of FIG. 3, the elastic conductor of the present invention can form a three-dimensional network structure on a silicone resin, which is a typical example of the rubber-like elastic resin 15, and can contact and conduct with each other. It has a configuration in which the needle-shaped conductive filler 20 is contained.
As the rubber-like elastic resin 15, a silicone resin having a rubber hardness (JIS A) of 28 was used. The conductive filler 20 includes a core material made of whiskers and a conductive film coated on a surface layer of the core material, and the conductive film is any one of Au, Ag, Ni, and Sn. Or an alloy containing at least two of these metals. In the present embodiment, for example, as the conductive filler 20, an inorganic compound whisker plated with Ag is used, and a filler having a filler diameter of about 0.5 μm and a filler length of about 20 μm is used.
FIGS. 4A and 4B show the volume resistivity and the rubber hardness (JIS A) of such an elastic conductor. First, as for the volume resistivity, as shown in FIG. 4A, the elastic conductor using the flake-like filler has a higher volume resistivity than the elastic conductor using the needle-like conductive filler 20. Will be higher. Therefore, it is clear that the elastic conductor of the present invention has higher conductivity. As for the rubber hardness, as shown in FIG. 4 (b), the needle-shaped conductive filler 20 has a clearly lower rubber hardness than the elastic conductor using the flake-shaped filler. It is clear that the elastic conductor of the present invention has a stronger suction holding force as a suction cup. Moreover, in the elastic conductor of the present invention, even if the compounding amount of the needle-shaped conductive filler 20 is increased, the hardness becomes only lower than the hardness of the elastic conductor containing the flake-shaped filler. Absent.
[0012]
Next, FIG. 5 shows the evaluation results as a conductive suction cup.
Here, the contact resistance and the holding time by the suction cup were evaluated when the compounding ratio of the needle-shaped conductive filler 20 to the rubber-like elastic resin 15 was divided into four stages from 40 wt% to 70 wt%.
As a result, it was found that when the compounding ratio of the needle-shaped conductive filler was set to 50 wt% or 60 wt%, the contact resistance was reduced, the conductivity was increased, and a sufficient attraction force could be maintained.
Next, the conductive filler 20, which forms a three-dimensional network structure and can be brought into contact with each other, is constituted by a core material made of whiskers and a conductive film coated on the surface layer of the core material. The material is formed, for example, by embedding nickel in fine pores of an aluminum anodic oxide film by Ni electrolytic plating and dissolving and removing the aluminum anodic oxide film. Here, a Ni filler having a diameter of 0.1 μmφ and a length of 30 μm was manufactured as a conductive filler core material. Applying Au or Ag plating to the surface layer of the conductive filler core material can reduce the contact resistance. Since the needle-shaped metal filler 20 has excellent bending characteristics, the needle-shaped metal filler 20 has such a characteristic that mutual contact with a three-dimensional network structure can be more easily formed.
Next, a conductive suction cup according to another embodiment of the present invention is characterized in that the rubber-like elastic resin 15 is a silicone resin having both ultraviolet curability and moisture curability.
That is, first, as can be seen from FIG. 4A, the elastic conductor constituting the conductive suction cup 1 of the present invention can obtain high conductivity even if the content of the conductive filler 20 is reduced, Is characterized by the fact that light penetrates into the inner layer more than the elastic conductor containing the flake-like filler because of having a needle shape.
When a silicone resin (for example, 3164 made of Three Bond) having both ultraviolet curability and moisture curability as the rubber-like elastic resin 15 is irradiated with ultraviolet rays in a state where an elastic conductor obtained by kneading a needle-shaped conductive filler into a required shape is formed. It is possible to completely cure the inside by irradiating ultraviolet rays, but after curing only the surface layer vicinity, it is also possible to use the moisture curing function by storing in a normal temperature and normal humidity environment to reach complete curing. it can. According to this method, complete hardening of at least the surface layer of the elastic conductor can be completed in a short time, and since heating is not required, a conductive suction cup can be formed on an electronic component that cannot be heated.
[0013]
Next, FIG. 6 is a cross-sectional view showing a configuration of the conductive suction cup sheet according to one embodiment of the present invention.
The conductive elastic sheet 5 according to this embodiment has a plurality of conductive suction cups 1 arranged in a matrix on the lower surface of a sheet portion made of an elastic conductor.
By providing the suction cups 1 in a matrix, it is possible to short-circuit the electrodes by adsorbing the adjacent arbitrary electrodes 12 among the electrodes 12 provided on the substrate 11 shown in FIG. It becomes possible. For example, by contacting a conductive sucker sheet across the electrode pattern of a device formed of a thin film, a short circuit can be made with low resistance without damaging the thin film, and failure analysis and the like can be easily performed. it can.
Next, FIG. 7 is a perspective view showing a configuration of a conductive sucker sheet according to another embodiment of the present invention. In the conductive suction cup sheet 5 according to this embodiment, a part or the whole of the lower surface of the elastic conductor sheet except for a part of each suction cup 1 exposing the recess 6 on the lower surface of the elastic conductor sheet is an insulating portion (insulating layer). ) 25.
As shown in FIG. 2, in the substrate 11 provided with the plurality of electrodes 12, in order to short-circuit only an arbitrary electrode 12, a portion (lower surface) other than the suction cup 1 of the conductive suction sheet 5 is connected to another part of the substrate 11. It is necessary to be configured to ensure insulation when contacting a part. For this reason, an insulating layer 25 is formed on the lower surface of the conductive sucker sheet excluding the suction cup 1 so that only the suction cup 1 adsorbed to the electrode 12 can be electrically connected to the electrode.
In this case, the suction cups are arranged so that the suction cups 1 are adsorbed only to any one of the electrodes 12 arranged in a plurality, and the lower surface of the substrate other than the suction cups may be insulated and covered with the insulating layer 25.
[0014]
8A, 8B, and 8C are a perspective view, a cross-sectional view taken along the line AA, and a cross-sectional view illustrating an application example of a conductive suction cup according to another embodiment of the present invention.
As shown in FIG. 3, the elastic conductor constituting the conductive suction cup 1 according to this embodiment forms a three-dimensional network structure in a silicone resin, which is a typical example of the rubber-like elastic resin 15, and is mutually connected. It has a configuration in which a needle-shaped conductive filler 20 capable of contact conduction is contained. The conductive suction cup 1 includes a suction cup body 3 made of an elastic conductor, and a metal foil 30 fixed to a flat bottom surface (thin deformed portion) 3a of the suction cup body 3. The reason why the metal foil 30 is fixed to the suction cup body 3 is to enable bonding using a binder such as solder or a conductive adhesive. Therefore, as the metal foil 30 to be used, a material that is familiar with the solder and the conductive adhesive is selected. For example, the metal foil 30 may be only a Cu foil, but it is preferable to apply Au and Ag plating to the surface layer in order to reduce the contact resistance with the suction cup body 3. The conductive sucker 1 with a metal foil can be retrofitted as a single conductive part even to a three-dimensional structure in which it is difficult to directly fix the conductive sucker to the electrode. Further, as shown in FIG. 8C, if the contact probe 31 is fixed to the tip of the contact probe 31 by soldering or the like afterwards, the contact probe 31 can ensure conduction with the electrode without a holding mechanism. Here, as a method of retrofitting the conductive suction cup 1 to the tip of the contact probe, soldering, bonding with a binder 32 such as a conductive adhesive, or the like can be used.
If a conductive suction cup without metal foil is fixed to the electrode, soldering cannot be performed and sufficient strength can be secured even when bonding with a conductive adhesive due to poor adhesive wettability of the elastic resin. These problems could not be solved by attaching a metal foil.
[0015]
Next, FIG. 9 shows an application example of a conductive suction cup according to another embodiment of the present invention. In this example, the conductive suction cup 1 is formed on an electrode terminal 51 of a flexible wiring board 50 (FPC).
By forming the conductive suction cup 1 on the FPC 50, the resistance of the wiring portion can be reduced, and the electrical resistance including the contact resistance when the electrode terminals are short-circuited can be reduced. In addition, since the FPC 50 is highly flexible, good suction cup adhesion characteristics and good contact resistance characteristics can be ensured even for conduction between different electrode surfaces of the three-dimensional structure.
Next, FIGS. 10A and 10B are diagrams showing a manufacturing procedure of the FPC 50 with a conductive suction cup shown in FIG.
The method of forming the conductive suction cup 1 on the electrode terminal 51 of the FPC 50 is as follows. That is, first, as shown in FIG. 10A, the ultraviolet curable silicone resin 15 (FIG. 3) and the conductive filler 20 (FIG. 3) which form a three-dimensional network structure and are in contact with and conductive to each other are kneaded. The conductive paste 55 is supplied to the FPC electrode terminal 51 or to a suction cup forming tool 56 having a convex shape. In the illustrated example, the conductive paste 55 is supplied on the FPC electrode terminals 51. The conductive paste 55 can be supplied by a method such as screen printing, dispensing, or transferring. Then, by irradiating ultraviolet rays while pressing the suction cup forming tool 56 on the electrode terminals 51 in a state where the gap is controlled, a concave conductive suction cup can be formed on the FPC electrode terminals. Here, as the suction cup forming tool 56, it is necessary to use a material having a small surface energy or to perform a surface treatment.
Next, FIGS. 11A and 11B are a cross-sectional view showing a configuration of a conductive suction cup according to another embodiment of the present invention, and a view showing an application example.
The conductive suction cup 1 according to this embodiment has a configuration in which the conductive suction cup 1 is electrically and mechanically connected to the end of an electric wire 60.
If the conductive suction cup 1 is formed at the tip of the electric wire 60, for example, when trying to extract an electric signal from the predetermined electrode terminal 12, by clamping the electric wire portion in addition to the contact at the suction cup portion, the electric signal is transmitted. Extraction becomes possible. If the individual electric wire portions are soldered or the like, it is possible to take out an electric signal while short-circuiting any of the electrode terminals.
[0016]
【The invention's effect】
As described above, according to the present invention, it is easy to mechanically fix or remove an object to be inspected such as an electrode, and the conductive member having a suction cup structure that can ensure high conduction is provided. This eliminates the need for a dedicated pressure welding jig at the time of contact, does not damage the contacting electrodes and the like, and also facilitates taking out of electrodes when the three-dimensional structure is to be inspected. By using an integrally molded product having both a suction function and a conductive function, it is possible to reduce the size and to cope with electrodes with a narrow pitch. In addition, by having the elasticity necessary to exhibit the suction cup function of elastically deforming and adsorbing to the electrodes, etc., and the high conductivity for exhibiting high conduction, it is simple to use without special pressure welding jigs etc. The structure and miniaturization can be realized. In addition, since the conductive filler itself kneaded into the rubber-like elastic resin has a structure that ensures stable conduction with each other, the conductive filler having a desired conductivity and a mechanical attraction force without using metal particles or the like in combination. It becomes possible to obtain a suction cup.
That is, according to the first aspect of the present invention, since an elastic conductor containing at least a resin having rubber-like elasticity and a conductive filler which forms a three-dimensional network structure and makes contact and conduct with each other is used, a conductive material is provided. It has both properties and low elasticity, and by forming it in the shape of a suction cup, it is possible to secure conduction with electrode terminals that can be easily detached. In addition, since the conductive filler itself has a needle-like shape, and has a structure that is easily connected in a mesh shape so that high conductivity can be obtained with each other, without going through a complicated procedure such as adding metal powder or the like. In addition, the material can be manufactured at low cost, and good workability can be maintained.
According to the second aspect of the present invention, a conductive filler having a small diameter and a high aspect ratio can be easily manufactured, and both the elastic properties and the contact resistance properties required for the conductive suction cup can be achieved.
According to the third aspect of the present invention, a needle-shaped conductive filler which forms a three-dimensional network structure and easily contacts and conducts with each other is employed because such a manufacturing method is employed as a method of forming a whisker-shaped core material. It can be easily formed.
According to the invention of claim 4, since the rubber-like elastic resin has ultraviolet curability and moisture curability, in producing a conductive suction cup, ultraviolet irradiation that can be manufactured in a short time without heating is required. As a result, the curing time of the rubber-like elastic resin can be shortened to increase the productivity.
[0017]
According to the invention of claim 5, the conductive sucker is a conductive member that can be soldered, and it is possible to easily take out an electrode from an arbitrary terminal as a post-installed component.
According to the conductive sucker sheet according to the invention of claim 6, since the conductive suckers are integrally formed in a matrix on the sheet-like elastic conductor, a short circuit between adjacent electrode patterns may damage the electrodes. It can be easily attached and detached without using.
According to the conductive sucker sheet according to the seventh aspect of the present invention, the sheet having the conductive suckers arranged in a matrix is provided with an insulating portion on at least a part of the surface thereof, so that any electrode having the sucker portion adhered thereto is provided. Only the terminals can be short-circuited.
According to the flexible wiring board according to the eighth aspect of the present invention, by forming a conductive suction cup on the electrode terminal of the FPC, it is possible to easily short-circuit any electrode terminal and to reduce the short-circuit resistance.
According to the ninth aspect of the present invention, it is possible to realize a method of forming a conductive suction cup on an electrode terminal, which can eliminate a dedicated mold and reduce manufacturing costs.
According to the wire for terminal withdrawal according to the invention of claim 10, the conductive suction cup is formed at the tip of the conductor constituting the wire, so that the electrode withdrawal can be performed by the wire in a detachable manner with respect to the electrode terminal provided on the substrate side. It becomes possible.
[Brief description of the drawings]
FIGS. 1A and 1B are a cross-sectional view showing a configuration of a conductive suction cup according to an embodiment of the present invention, and a view showing a contact state, respectively.
FIGS. 2A and 2B are configuration diagrams of a conductive suction cup according to another embodiment of the present invention.
FIG. 3 is an enlarged sectional view showing a configuration of an example of an elastic conductor of the present invention.
FIGS. 4A and 4B are diagrams respectively showing the volume resistivity and the elastic characteristic of the elastic conductive resin of the present invention.
FIG. 5 is a view showing evaluation results of the conductive suction cup of the present invention.
FIG. 6 is a cross-sectional view showing a configuration of a conductive sucker sheet according to one embodiment of the present invention.
FIG. 7 is a perspective view showing a configuration of a conductive sucker sheet according to another embodiment of the present invention.
FIGS. 8A, 8B, and 8C are a perspective view, a cross-sectional view taken along the line AA, and a cross-sectional view illustrating an application example of a conductive suction cup according to another embodiment of the present invention.
FIG. 9 is a diagram showing an application example of a conductive suction cup according to another embodiment of the present invention.
FIGS. 10 (a) and (b) are views showing a manufacturing procedure of the FPC 50 with a conductive sucker shown in FIG. 9;
11A and 11B are a cross-sectional view showing a configuration of a conductive suction cup according to another embodiment of the present invention, and a view showing an application example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conductive suction cup, 2 support parts, 3 suction cup main bodies, 3a bottom face (thin deformation part), 5 conductive suction sheets, 6 recesses, 7 thin deformation parts, 11 substrates, 12 electrodes (electrode terminals), 15 rubber elasticity Resin, 20 needle-shaped conductive filler, 25 insulating part (insulating layer), 30 metal foil, 31 contact probe, 32 binder, 50 flexible wiring board (FPC), 51 electrode terminal, 55 conductive paste.

Claims

In a conductive suction cup made of an elastic conductor in a suction cup shape,
The elastic conductor includes at least a rubber-like elastic resin and a conductive filler mixed with the rubber-like elastic resin,
The conductive sucker, wherein the conductive filler forms a three-dimensional network structure in the rubber-like elastic resin and is in contact with and conductive to each other.

The conductive filler comprises a core material made of whiskers, and a conductive film coated on a surface layer of the core material,
2. The conductive suction cup according to claim 1, wherein the conductive coating is made of one of Au, Ag, Ni, and Sn, or an alloy containing at least two of them. 3. .

3. The conductive suction cup according to claim 2, wherein the core material of the conductive filler is formed by filling a metal into micropores of the aluminum anodic oxide film and then removing the aluminum anodic oxide film. .

4. The conductive suction cup according to claim 1, wherein the rubbery elastic resin is a silicone resin having both ultraviolet curability and moisture curability. 5.

The conductive sucker according to claim 1, wherein a metal foil that can be soldered is disposed on a back surface of the conductive sucker.

A conductive sucker sheet comprising a plurality of conductive suckers according to any one of claims 1 to 4, which are arranged in a matrix on a sheet surface made of an elastic conductor.

The conductive suction cup sheet according to claim 6, wherein an insulating layer is provided on at least a part of the surface of the elastic conductor located between the conductive suction cups.

5. A flexible wiring board, wherein the conductive suction cup according to claim 1 is disposed on an electrode of the flexible wiring board.

A method for arranging the conductive suction cup according to claim 1 on an electrode of a flexible wiring board,
A step of supplying a conductive paste containing an ultraviolet-curable silicone resin and a conductive filler that forms a three-dimensional network structure and is in contact with each other on the electrode of the flexible plate or the tip of the suction cup forming tool,
Forming a conductive suction cup by irradiating with ultraviolet light after pressing the suction cup forming tool on the electrode in a state where the gap is controlled.

A terminal drawing wire, wherein the conductive suction cup according to any one of claims 1 to 4 is electrically and mechanically fixed to a conductor end of the wire.