JP2004198329A - Failure diagnosis method, failure diagnosis system, and printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for diagnosing failure of a circuit board achieving a framework of failure diagnosis with usability at a low cost. <P>SOLUTION: A spiral coil 30 making a magnetic field sensing part is formed of a printer wiring pattern so that a physical position relation between a winding of the coil and a diagnostic object part is maintained in a constant state for one to one to the individual diagnostic object part at a prescribed position corresponding to the object part of the failure diagnosis. Terminals 31 and 32 being open ends of the spiral coil 30 connect a failure diagnosis part 90 for detecting the existence of failure in the circuit board 10. The failure diagnosis part 90 detects an inductive electromotive force induced to the spiral coil 30 by a magnetic field generated by supplying a power source to the circuit board 10 and operating a circuit member. The existence of the failure is determined as the whole board by being compared with the inductive electromotive force of a previously measured normal state. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３４】
なお、磁界センシング部としてのスパイラルコイル３０に発生する誘導起電力を読み取るものであればよく、式（１）で示したように、スパイラルコイル３０の開放端に生じる誘起起電圧を読み取る態様に限らず、スパイラルコイル３０に流れる電流を読み取る態様としてもよい。
【００３５】
隣接配線の影響を軽減するには、検査対象の配線パターン２６ａに隣接する配線パターン２６ｂからの磁界ができるだけスパイラルコイル３０を通過しないようにすることが好ましい。このためには、スパイラルコイル３０の磁路長が回路基板の故障診断の対象部位に応じた所定の配線パターンの幅と略同一もしくはそれ以下であることが好ましい。
【００３６】
また、精度のよい検査をするには、検査対象の配線パターン２６ａとスパイラルコイル３０との物理的な位置関係を固定することが望ましい。故障診断の対象部位に応じた所定の配線パターンに対して固定的にスパイラルコイル３０を配置するに際しては、回路基板上の外層（表面や裏面）もしくは内層にプリント配線パターンにより形成するとよい。
【００３７】
また、予め巻き線にて形成したコイルをテーピング部材などの固定部材を用いて電気的に非接触となるように、略密着して固定してもよい。この際には、たとえば、磁路の開口部断面が略円形若しくは楕円状にコイルを形成した後に、そのコイルを扁平状にしてから、診断対象部位に対応する位置に、診断対象部位の配線パターンとコイルの扁平面とが対向するように固定配置してもよい。こうすることで、配置の安定性がよくなる。
【００３８】
図２は、図１に示した仕組みを利用した故障診断システムの一例を示す図である。ここで、図２（Ａ）は第１例のスパイラルコイル３０の平面透視図とともに故障診断システムの概略を示した図、図２（Ｂ）は図２（Ａ）のＸ−Ｘ線（スルーホール部）におけるスパイラルコイル３０の断面透視図、図２（Ｃ）はスパイラルコイル３０の回路シンボル図、図２（Ｄ）は故障診断システム１を構成する故障診断部９０の詳細例を示したブロック図である。図２（Ｃ）の回路記号の第１の端子３１と第２の端子３２は、図２（Ａ）の平面透視図の第１の端子３１と第２の端子３２にそれぞれ対応している。
【００３９】
故障診断システム１は、検査対象の配線パターン２６に対応するように配置されたスパイラルコイル３０と、スパイラルコイル３０により検出された誘導起電力に基づいて配線パターン２６における信号の故障の有無を診断する故障診断部９０とから構成されている。
【００４０】
図２（Ｂ）に示すように、回路基板１０は、２枚の絶縁体３７が積層されており、一方（図では右側）の絶縁体３７ａの表面に配線パターン２６がプリント形成されている。そして、絶縁体３７ａを挟んだ配線パターン２６に対向する反対側の（図では左側）の絶縁体３７ｂの両面に形成されたプリント配線パターンにて、第１例のスパイラルコイル３０が形成されている。つまり、第１例のスパイラルコイル３０は、回路を構成する回路基板（プリント配線基板）１０と同一基板上に構成されている。
【００４１】
具体的には、第１例のスパイラルコイル３０は、対向する２層の導体層の一部を切り取ってできる複数の導体（それぞれ複数本配された第１の導体３４および第２の導体３５）をスルーホール（バイアホール）３６を使用して所定の順に（巻き線を形成するように）接続して構成されている。スルーホール３６の間には、絶縁体３７ｂと同様の絶縁体３７ｃが配されている。
【００４２】
図２（Ａ）に示すように、スパイラルコイル３０の開放端である第１の端子３１および第２の端子３２には、回路基板１０における故障の有無を検出するための故障診断部９０が接続されるようになっている。故障診断部９０は、回路基板１０に電源が供給され回路部材が動作することで配線パターン２６にて発生する磁界によりスパイラルコイル３０に誘起される誘導起電力を検出する。そして、予め測定しておいた正常状態の誘導起電力（つまり期待値）と実働状態の誘導起電力とを比較することにより、回路基板１０における故障の有無を診断する。なお、故障診断部９０を回路基板１０上に設けることで、装置の起動時などに装置自身が基板の診断を行なう自己診断システムを構築するようにしてもよい。
【００４３】
図２（Ｄ）に示すように、故障診断部９０は、スパイラルコイル３０に誘起される誘導起電力を検出するとともに所定レベルに増幅する差動増幅器で構成されたバッファ９２と、バッファ９２から出力されたアナログ電圧をデジタルデータに変換するＡ／Ｄ（Analog to Digital ）変換部９４と、正常時にスパイラルコイル３０に誘起された誘導起電力（期待値）を記憶する半導体メモリなどの記憶部９６と、記憶部９６に記憶された期待値と実働状態の誘導起電力とを比較して故障の有無を判定する比較判定部９８と、故障診断システム１の全体を制御する制御部９９とを備えている。
【００４４】
スパイラルコイル３０に誘起された誘導起電力はバッファ９２により所定レベルに増幅された後にＡ／Ｄ変換部９４によってデジタルデータに変換される。たとえば、制御部９９は、正常動作時に、スパイラルコイル３０の誘導起電力信号を取り込み、記憶部９６に記憶させておく。なお、１回の測定で得られた誘導起電力信号をもとに特徴抽出を行なって期待値としてもよいし、複数回検知した平均的なデータを期待値してもよい。
【００４５】
次に、比較判定部９８は、実際に回路を動作させて、スパイラルコイル３０の誘導起電力信号を常時取り込みながら、制御部９９の指示に従い、記憶部９６に記憶しておいた正常時の波形と常時取り込んでいる波形とを常に比較し、波形に差が生じた時に、回路基板の配線や搭載部品に故障が生じていると判定する。そして、故障を検知した際には、図示しない警報部で警報（アラーム）を発するか故障内容を通知するようにする。警報部は、故障診断部９０を有する装置の内部に設けてもよいし、故障診断部９０が診断対象装置から遠くに離れた場所にある場合などは、電話回線やインターネットを介して装置の状態を集中管理する場所に設置して、そこで警報を発するようにしてもよい。
【００４６】
なお、たとえば、読み取った波形の特徴を解析する特徴量抽出部を設けて、故障した際の波形の変化状態を詳細に解析することで、さらに故障内容を詳しく同定することもできる。また、単なる波形比較に限らず、たとえば、周波数解析部を設けて、読み取った波形をフーリエ変換すること（図示せず）などにより、ピークが発生する周波数値を確認することで、回路基板１０に異常が発生しているかどうかを解析する構成としてもよい。
【００４７】
図２に示したような構成によれば、プリント配線パターンによりスパイラルコイル３０を形成しているので、特段の固定部材を用いることなく、磁界センシング部として機能するスパイラルコイル３０と回路基板１０上の診断対象部位である配線パターン２６との物理的な位置関係を固定することができる。そしてこれにより、期待値取得時（正常時）や故障診断中の誘導起電力の状態を確実に安定化させることができる。つまり、故障診断の判断指標となる誘導起電力を精度よく取得することができ、診断性能も向上する。
【００４８】
また、プリント配線パターンによりスパイラルコイル３０を固定配置しているので、当然に、診断箇所にプローブを近づけて観察したり、プローブを対象部位に近づけたりするためのメカニカルな手段を必要としない。回路基板を作り込むときに、磁界センシング用のスパイラルコイル３０を診断対象部位である配線パターンに（複数の場合にはそれぞれに）応じて一体的にパターンニングしておけばよいので、基板としての付加的なコストは殆ど掛からず、低コストで、実現することができる。
【００４９】
これにより、任意の複数の範囲の回路動作をモニタする場合でも、電子回路に複雑な故障診断回路を付加することなく、低コストで磁界センシング部をシステムに組み込み可能で、しかも高精度に回路動作を監視することのできる故障診断システムを提供することができるようになる。
【００５０】
図３は、回路を構成する回路基板１０と同一基板上にスパイラルコイルを構成する第２例を示した図である。ここで、図３（Ａ）は第２例のスパイラルコイル５０と配線パターン６０との空間的な配置関係を示した図、図３（Ｂ）は平面透視図、図３（Ｃ）は図３（Ａ）におけるＸ−Ｘ線（スルーホール部）のスパイラルコイル５０部分の断面透視図である。
【００５１】
図３（Ｃ）に示すように、回路基板１０は、配線パターン６０を構成する第１の配線層６１、グランド層６５、電源層６４、および第２の配線層６２が、この順に、絶縁層６７を挟んで積層された回路基板として構成されている。そして、第１の配線層６１の絶縁層６７を挟んだ対向する反対側の（図では上側）に、プリント配線パターンにて、第２例のスパイラルコイル５０が、さらに積層されてパターン形成されている。
【００５２】
つまり、第２例のスパイラルコイル５０も、回路を構成する回路基板１０と同一基板上に構成されている。具体的には、第２例のスパイラルコイル５０は、配線パターン６０を構成する層の上に、２つのコイル層（導体層）５１，５２と絶縁層５７とが追加され、第１のコイル層５１には第１の導体５４が、第２のコイル層５２には第２の導体５５が、それぞれ複数本分パターン形成されている。
【００５３】
そして、第１の導体５４および第２の導体５５をスルーホール５６を使用して所定の順に（巻き線を形成するように）接続することで、第２例のスパイラルコイル５０が形成されている。絶縁層５７内におけるスルーホール５６の間には、外側の絶縁層５７を構成する絶縁性の基材と同様の絶縁体５７ｃが配され絶縁層５７の一部を構成するようになっている。
【００５４】
スパイラルコイル５０の配置は、回路動作をモニタすべき配線パターン６０（特に第１の導体７４にて形成されるスパイラルコイル５０と対向する配線）の上に配置するが、その際、図３（Ａ）に示すように、コイルの径方向をＷ、磁路長方向をＬＥＮとすると、磁路長ＬＥＮは配線幅ＰＷと略同一もしくは小さくすることで、隣接配線の磁束の影響を最小限にし、かつ対象配線による磁束を効率よく検出することができるようになる。
【００５５】
第１のコイル層５１と第２のコイル層５２との間隔は絶縁層５７の厚さに依存し、使用する基板仕様によって制限を受けやすい（設定の自由度がない）が、コイル径Ｗは、第１の導体５４および第２の導体５５のパターン長さ（両端のスルーホール５６の間隔にほぼ等しい）で調整可能である。コイル径Ｗを大きくすることで、スパイラルコイル５０を通過する磁束が増加するので、第１の導体５４および第２の導体５５のパターン長さをパターン設計時に調整することで、誘導起電力の大きさに応じてコイル径Ｗを調整することができる。
【００５６】
図４は、スパイラルコイルの第３例を示した図である。ここで、図４（Ａ）は第３例のスパイラルコイル７０と配線パターン６０との空間的な配置関係を示した図、図４（Ｂ）は、図４（Ａ）におけるＸ−Ｘ線（スルーホール部）のスパイラルコイル７０部分の断面透視図である。
【００５７】
この第３例のスパイラルコイル７０は、回路を構成するプリント配線基板８８とは別の基板、たとえばＦＰＣ（Flexible Printed Circuit；フレキシブル配線）基板７８の上に第１例と同様にスパイラルコイル７０を形成し、スパイラルコイル７０が形成されたＦＰＣ基板７８をプリント配線基板８８に近接して配置する。
【００５８】
具体的には、第３例のスパイラルコイル７０は、２つのコイル層（導体層）７１，７２と絶縁層７７とが設けられ、第１のコイル層７１には第１の導体７４が、第２のコイル層７２には第２の導体７５が、それぞれ複数本分パターン形成されている。そして、第１の導体７４および第２の導体７５をスルーホール７６を使用して所定の順に（巻き線を形成するように）接続することで、第３例のスパイラルコイル７０が形成されている。
【００５９】
絶縁層７７内におけるスルーホール７６の間には、外側の絶縁層７７を構成する絶縁性の基材と同様の絶縁体７７ｃが配され絶縁層７７の一部を構成するようになっている。２つのコイル層７１，７２の表面にも絶縁層７７が形成されている。絶縁層７７を構成する基材としては、柔軟性のあるプラスチック部材（たとえばポリイミドなど）が使用される。
【００６０】
回路を構成するプリント配線基板８８は、第２例で示した回路基板１０における配線パターン６０部分と同じように、配線パターン８０を構成する第１の配線層８１、グランド層８５、電源層８４、および第２の配線層８２が、この順に、絶縁層８６７を挟んで積層された回路基板として構成されている。
【００６１】
ＦＰＣ基板７８上のスパイラルコイル７０もやはり、回路動作をモニタしたい配線パターン８０（特に第１の配線層８１内の配線）に対応してスパイラルコイル７０が配置されるように構成し、位置を合わせて近接配置する。
【００６２】
図５は、スパイラルコイルの第４例を示した図であり、スパイラルコイル部分の断面透視図を示している。この第４例のスパイラルコイル５０は、第２例のスパイラルコイル５０を変形したものであって、スパイラルコイル５０を形成する対向する２つのコイル層（導体層）５１，５２の間に配される絶縁層５７の一部、具体的には、絶縁層５７内におけるスルーホール５６の間に配されていた絶縁体５７ｃやスルーホール５６の外側を、絶縁性磁性体層５９に置き換えた構造となっている。つまり、スパイラルコイル５０を構成するために用いられる対向する２層の導体層（コイル層５１，５２）間の一部に絶縁性の磁性材が層状に配置された構造となっている。
【００６３】
２層の導体層間に絶縁性の磁性材を層状に配置する技術としては、たとえば特開平１１−４０９１５号に記載の技術を利用するのがよい。たとえば、絶縁性磁性体層５９を構成する磁性材として、絶縁性磁性体を用いるとよい。絶縁性磁性体は、たとえば、Ｎｉ−Ｚｎ系フェライト微粒粉末、Ｍｎ−Ｚｎ系フェライト微粒粉末、センダスト微粒粉末、あるいはＬｉ系フェライト微粒粉末と、絶縁溶剤との混合物が用いられるとよい。絶縁溶剤にはエポキシ系絶縁溶剤が含まれる。
【００６４】
なお、２つのコイル層５１，５２間に配置される絶縁性の磁性体として、両面に絶縁コーティングが施された金属箔が用いられてもよい。両面に絶縁コーティングが施された金属箔は、アモルファス磁性箔多層帯を含む。
【００６５】
さらに、絶縁層５７内におけるスルーホール５６の間に配されていた絶縁体５７ｃの部分に限らず、絶縁層５７の全体を絶縁性磁性体層５９に置き換えてもよい。つまり、スパイラルコイル５０を構成するために用いられる対向する２層の導体層（コイル層５１，５２）間の全面領域に絶縁性の磁性材が層状に配置された構造としてもよい。
【００６６】
このように、スパイラルコイル５０を構成するために用いられる対向する２層の導体層（コイル層５１，５２）間の一部または全面領域に絶縁性の磁性材を配することで、スパイラルコイル５０のインダクタンスを増大することができるので、スパイラルコイル５０の感度を向上させることができ、より精度の高い故障診断システムを構築することができる。
【００６７】
なお、この第４例のように、絶縁性磁性体層を配する仕組みは、第２例のスパイラルコイル５０に対してだけでなく、他のものにも同様に適用することができる。たとえば、第１例のスパイラルコイル３０を構成する２層のコイル層３１，３２間の一部、つまりスルーホール３６の間に配された絶縁体３７ｃ、あるいは層間の全面領域に、絶縁性の磁性材を配してもよい。同様に、第３例のスパイラルコイル７０を構成する２層のコイル層７１，７２間の一部、つまりスルーホール７６の間に配された絶縁体７７ｃ、あるいは層間の全面領域に、絶縁性の磁性材を配してもよい。
【００６８】
図６は、回路およびプリント配線基板に故障診断システム１を適用した例を説明する図である。ここで、図６（Ａ）は、デジタル信号Ｖｉｎを入力して負荷抵抗としての抵抗素子２５に電流Ｉｏｕｔを流すオープンコレクタ型のインバータ回路を示したものである。また、図６（Ｂ）は、インバータ回路が配されたプリント配線基板上にスパイラルコイルを配置した例を示す図、図６（Ｃ）は、インバータ回路を動作させたときの信号波形の一例を示す図である。
【００６９】
図６（Ａ）に示すように、オープンコレクタ型のインバータ回路は、オープンコレクタのインバータ素子２３の出力に抵抗素子２５がプルアップ抵抗として接続されて構成されている。図６（Ｂ）に示す例では、インバータ素子２３が内部に複数配されたインバータＩＣ２４の端子２４ａに配線パターン２６を介して抵抗素子２５の一方の端子が接続されている。抵抗素子２５の他方の端子は配線パターン２６を介して図示しない電源に接続される。
【００７０】
そして、端子２４ａに接続された配線パターン２６を検知対象とする第１例のスパイラルコイル３０が、その配線パターン２６上に配置されている。スパイラルコイル３０の両端は、図示しない故障診断部９０に接続される（図２（Ｄ）を参照）。スパイラルコイル３０は、第１例のものに限らず、第２例〜第４例のものであってもよい。
【００７１】
ここで、インバータ素子２３に入力される入力電圧Ｖｉｎがローレベルのときは、オープンコレクタ型のインバータ素子２３の出力はハイインピーダンス状態となり、抵抗素子２５にてプルアップされたインバータ素子２３は、その出力がハイレベルとなる。そして、インバータ素子２３の入力電圧Ｖｉｎがローレベルからハイレベルに遷移すると、オープンコレクタ型のインバータ素子２３の出力はローレベルに遷移するため、抵抗素子２５に電流Ｉｏｕｔが流れる。
【００７２】
この抵抗素子２５における電流の変動量がスパイラルコイル３０の誘導起電力として出力されるので、回路が正常であれば、スパイラルコイル３０には、図６（Ｃ−１）に示すような微分波形が出力される。一方、たとえば、インバータ素子２３が正常であって抵抗素子２５が故障してオープン状態となった場合（故障時の一例）、図６（Ｃ−２）に示すように、インバータ素子２３の入力電圧Ｖｉｎがローレベルからハイレベルに遷移しても、抵抗素子２５には電流が流れなくなるので、スパイラルコイル３０には誘導起電力は出力されない。
【００７３】
よって、図示しない故障診断部９０は、常時行なっている正常波形との比較処理において、波形の差が生じていると判断することができる。つまり、回路（本例では抵抗素子２５）に故障が生じたことを検知することができる。しかも、図６（Ｃ−２）に示す故障時の波形から、抵抗素子２５に電流Ｉｏｕｔが流れていないことが分かるので、インバータ素子２３が正常であるとした場合、抵抗素子２５のオープン故障と特定することができる。
【００７４】
図７は、ＣＰＵやメモリを利用してソフトウェア的に故障診断システムを構成する、すなわちパーソナルコンピュータなどの電子計算機を利用して故障診断システムを構築する場合のハードウェア構成の一例を示した図である。
【００７５】
故障診断部９０を構成するコンピュータシステム９００は、ＣＰＵ９０２、ＲＯＭ（Read Only Memory）９０４、ＲＡＭ９０６、および通信Ｉ／Ｆ（インタフェース）９０８を備える。ＲＡＭ９０６は、撮像画像データを格納する領域を含んでいる。
【００７６】
また、たとえばメモリ読出部９０７、ハードディスク装置９１４、フレキシブルディスク（ＦＤ）ドライブ９１６、あるいはＣＤ−ＲＯＭ（Compact Disk ROM）ドライブ９１８などの、記憶媒体からデータを読み出したり記録したりするための記録・読取装置を備えてもよい。データは、データバスを通じて各ハードウェア間をやり取りされる。
【００７７】
ハードディスク装置９１４、ＦＤドライブ９１６、あるいはＣＤ−ＲＯＭドライブ９１８は、たとえば、ＣＰＵ９０２にソフトウェア処理をさせるためのプログラムデータを登録するなどのために利用される。また、ハードディスク装置９１４は、処理対象データを格納する領域を含んでいる。
【００７８】
通信Ｉ／Ｆ９０８は、インターネットなどの通信網との間の通信データの受け渡しを仲介する。またコンピュータシステム９００は、回路基板１０との間のインタフェースの機能をなすＩ／Ｆ部９３０を備える。
【００７９】
なお、上記実施形態で示した故障診断部９０の各機能部分（特に比較判定部９８）の全ての処理をソフトウェアで行なうのではなく、これら機能部分の一部をハードウェアにて処理回路９４０として設けてもよい。
【００８０】
回路基板１０には、故障診断部９０の一部を構成する回路部材として、アナログマルチプレクサ９５０、バッファ回路９５２、およびＡ／Ｄ変換部９５４が配されている。たとえば、検査対象部位としての複数の配線パターン２６に対応するように、アナログマルチプレクサ９５０が設けられている。回路基板１０上における検査対象の個々の配線パターン２６には、第１例のスパイラルコイル３０が配される。スパイラルコイル３０は、第１例のものに限らず、第２例〜第４例のものであってもよい。
【００８１】
個々のスパイラルコイル３０は、その一方の端子が共通にグランドに接続され、他方の端子が、個々に、アナログマルチプレクサ９５０の対応する入力端子に接続されている。アナログマルチプレクサ９５０の選択動作は、コンピュータシステム９００側のＩ／Ｆ部９３０からの制御信号ＣＮＴにより制御されるようになっている。
【００８２】
アナログマルチプレクサ９５０の出力信号は、バッファ回路９５２を介してＡ／Ｄ変換部９５４によってデジタルデータに変換される。Ａ／Ｄ変換部９５４から出力されるデジタルの検知データは、図示しない出力バッファを介してコンピュータシステム９００側のＩ／Ｆ部９３０に入力される。
【００８３】
このような構成のコンピュータシステム９００は、上記実施形態に示した故障診断部９０の基本的な構成および動作と同様とすることができる。また、上述した処理をコンピュータに実行させるプログラムは、ＣＤ−ＲＯＭ９２２などの記録媒体を通じて配布される。あるいは、プログラムは、ＣＤ−ＲＯＭ９２２ではなくＦＤ９２０に格納されてもよい。また、ＭＯドライブを設け、ＭＯに前記プログラムを格納してもよく、またフラッシュメモリなどの不揮発性の半導体メモリカード９２４など、その他の記録媒体に前記プログラムを格納してもよい。
【００８４】
さらに、他のサーバなどからインターネットなどの通信網を経由して前記プログラムをダウンロードして取得したり、あるいは更新したりしてもよい。なお、記録媒体としては、ＦＤ９２０やＣＤ−ＲＯＭ９２２などの他にも、ＤＶＤなどの光学記録媒体、ＭＤなどの磁気記録媒体、ＰＤなどの光磁気記録媒体、テープ媒体、磁気記録媒体、ＩＣカードやミニチュアーカードなどの半導体メモリを用いることができる。
【００８５】
記録媒体の一例としてのＦＤ９２０やＣＤ−ＲＯＭ９２２などには、上記実施形態で説明した故障診断部９０における処理の一部または全ての機能を格納することができる。すなわち、ＲＡＭ９０６などにインストールされるソフトウェアは、上記実施形態に示された故障診断部９０と同様に、比較判定部９８や特徴量抽出部、あるいは周波数解析部などの機能部をソフトウェアとして備える。このようなソフトウェアは、故障監視用のアプリケーションソフトとして、ＣＤ−ＲＯＭやＦＤなどの可搬型の記憶媒体に格納され、あるいはネットワークを介して配布されるとよい。
【００８６】
そして、故障診断部９０をコンピュータにより構成する場合、ＣＤ−ＲＯＭドライブ９１８は、ＣＤ−ＲＯＭ９２２からデータまたはプログラムを読み取ってＣＰＵ９０２に渡す。そしてソフトウェアはＣＤ−ＲＯＭ９２２からハードディスク装置９１４にインストールされる。ハードディスク装置９１４は、ＦＤドライブ９１６またはＣＤ−ＲＯＭドライブ９１８によって読み出されたデータまたはプログラムや、ＣＰＵ９０２がプログラムを実行することにより作成されたデータを記憶するとともに、記憶したデータまたはプログラムを読み取ってＣＰＵ９０２に渡す。
【００８７】
ハードディスク装置９１４に格納されたソフトウェアは、ＲＡＭ９０６に読み出された後にＣＰＵ９０２により実行される。たとえばＣＰＵ９０２は、記録媒体の一例であるＲＯＭ９０４およびＲＡＭ９０６に格納されたプログラムに基づいて上記の処理を実行する。たとえば、先ず、正常動作時に、スパイラルコイル３０の誘導起電力信号をアナログマルチプレクサ９５０で切り換えながら取り込み、ハードディスク装置９１４などの記憶装置に記憶させておく。次に、実際に回路を動作させて、スパイラルコイル３０の信号を常時取り込みながら、ＣＰＵ９０２の指示に従い、ハードディスク装置９１４などに記憶しておいた正常時の波形と常時取り込んでいる波形とを常に比較し、波形に差が生じた時に、故障と判定して、アラームを発するか故障内容を通知する。また、故障した際の波形の変化状態を詳細に解析することで、さらに故障内容を詳しく同定する。
【００８８】
以上、本発明を実施形態を用いて説明したが、本発明の技術的範囲は上記実施形態に記載の範囲には限定されない。発明の要旨を逸脱しない範囲で上記実施形態に多様な変更または改良を加えることができ、そのような変更または改良を加えた形態も本発明の技術的範囲に含まれる。
【００８９】
また、上記の実施形態は、クレーム（請求項）にかかる発明を限定するものではなく、また実施形態の中で説明されている特徴の組合せの全てが発明の解決手段に必須であるとは限らない。前述した実施形態には種々の段階の発明が含まれており、開示される複数の構成要件における適宜の組合せにより種々の発明を抽出できる。実施形態に示される全構成要件から幾つかの構成要件が削除されても、効果が得られる限りにおいて、この幾つかの構成要件が削除された構成が発明として抽出され得る。
【００９０】
たとえば、上記実施形態で示した第１〜第４例のスパイラルコイルでは、スパイラルコイルを診断対象部位に対応するようにプリント基板上にパターン形成する態様を示したが、スパイラルコイルは、パターン形成以外の手法にて形成してもかまわない。たとえば、図１の説明にても述べたように、予め巻き線にて形成したコイルを、テーピング部材などの固定部材を用いて電気的に非接触となるように固定してもよい。
【００９１】
また、上記実施形態では、診断対象部位として、診断対象部品に接続されている配線パターンを一例に説明したが、故障診断の対象部位は、配線パターンに限るものではない。たとえば、対象部品の端子や部品そのものであってもよい。
【００９２】
【発明の効果】
以上のように、本発明によれば、スパイラルコイルを、個々の診断対象部位に対向する位置に固定的に配置するようにしたので、磁界センシング部として機能するスパイラルコイルと診断対象部位との物理的な位置関係を固定することができる。そしてこれにより、期待値取得時（正常時）や故障診断中の誘導起電力の状態を確実に安定化させることで、故障診断の判断指標となる誘導起電力を精度よく取得することができ、診断性能が向上する。
【００９３】
また、故障診断の対象部位に応じて、スパイラルコイルの設置数を自由に設定することができる。たとえば、任意の複数の範囲の回路動作をモニタする際には、その複数の部位に対して、スパイラルコイルを個々に配置することも容易である。これにより、任意の複数の範囲の回路動作をモニタするため、複数の複雑な専用プローブをシステム内に組み込んだり、そのプローブを移動させたりするなどの手段を必要としない。
【００９４】
このように、本発明によれば、故障診断部位の特定要求の度合いに応じてスパイラルコイルを適宜設置するだけの簡易な構造で足りるようになった。また、このことにより、コスト面と故障診断の対象部位の設定の自由度という点で、利用者にとって、使い勝手のよい故障診断の仕組みを提供することができるようになった。
【図面の簡単な説明】
【図１】本発明に係るスパイラルコイルの基本的な構成と作用を説明する図である。
【図２】図１に示した仕組みを利用した故障診断システムの一例を示す図である。
【図３】回路基板と同一基板上にスパイラルコイルを構成する第２例を示した図である。
【図４】スパイラルコイルの第３例を示した図である。
【図５】スパイラルコイルの第４例を示した図である。
【図６】回路およびプリント配線基板に故障診断システムを適用した例を説明する図である。
【図７】電子計算機を利用して故障診断システムを構築する場合のハードウェア構成の一例を示した図である。
【図８】人の手を介在することで、プローブを対象部位に近づけるための仕組みの概要を示す図である。
【符号の説明】
１…故障診断システム、１０…回路基板、３０，５０，７０…スパイラルコイル、２６，６０，８０…配線パターン、５９…絶縁性磁性体層、７８…ＦＰＣ基板（フレキシブル配線基板）、８８…プリント配線基板、９０…故障診断部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention predicts the operation, performance abnormality, or failure of a circuit member in a device having a circuit board on which a circuit member is mounted, for example, a printer device, a facsimile device, or a device such as a multifunction peripheral having those functions. The present invention relates to a method of detecting and detecting (hereinafter collectively referred to as a failure diagnosis), a failure diagnosis system for implementing the failure diagnosis method, and a printed wiring board used in the failure diagnosis system.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as electronic devices such as personal computers and copiers have been improved in performance and functions, analog and digital electronic circuits for various applications for realizing them have been increasingly stored in the form of printed circuit boards. .
[0003]
In addition, a number of electronic circuit boards with high reliability and high-speed and high-precision operation are mounted as means for operation control in other industrial devices such as automobiles, aviation, robots and semiconductor design devices. . These electronic circuit boards are connected via various cables in order to realize a series of functions, thereby achieving desired specifications.
[0004]
The environment in which the device on which such a board is mounted is used is usually in an office or a house, but it may be used in other harsh environments, and it is very diverse. Over. In particular, when the use environment is poor, various abnormalities and failures that are difficult to detect occur even if the device is used in a normal manner, and a great deal of labor is required to repair the abnormalities and failures.
[0005]
In addition, even when the electronic circuit is used in a normal use environment, an abnormality or a failure of the electronic circuit occurs, the frequency of the abnormality is not always low, and the detection location cannot often be specified. Further, when an abnormality occurs in the electronic circuit board, it is necessary to take an urgent action in terms of safety and cost.
[0006]
As a general method of fault diagnosis, a fault location is identified while monitoring (monitoring) the voltage and signal waveform of a main location using a measuring device such as a tester. However, in such a diagnostic method, it is necessary to perform measurement at various points, and trouble is required for trouble diagnosis, and there is a problem that work efficiency is poor.
[0007]
Therefore, as an efficient diagnosis method, there is a self-diagnosis system (Diagnostics system) in which the device itself diagnoses a failure of each substrate or an electronic circuit when the device is started. In this self-diagnosis system, a failure diagnosis circuit for monitoring a circuit operation in designing an electronic circuit is provided in advance. For example, a signal pattern (expected value) when the device is operating is further set for each circuit module or each board. Are monitored and stored in advance for each circuit part, and the output of the diagnostic circuit at the time of actual operation is compared with an expected value to determine whether or not a failure has occurred, and to specify the location of the failure.
[0008]
For example, when a service center is notified of an error or failure information about a copier or printer, a repair person rushes to the site to repair the failure based on the failure location information and failure history information recorded on the equipment. Measures such as specifying the part, replacing it, or performing repair work may be taken. Alternatively, if these devices are connected to a network and automatically transmit status management, failure information, etc. to the department that manages these information, the information must be analyzed in advance and repaired. Similar actions may be taken by the person in charge.
[0009]
However, when the above-described abnormality or failure occurs, there is a disadvantage on the user side that the device is normally unusable and downtime occurs. Also, for the maker side, it takes much time to specify the faulty part, and the faulty part cannot always be specified accurately, and measures such as replacing all the parts considered to be faulty cause a great cost, Or there are situations in which repair itself takes time, and manpower-like responses cannot keep up. Therefore, there is a fact that both the user side and the maker side frequently suffer a great loss.
[0010]
On the other hand, the operation of electronic circuits has become more and more complicated with the recent improvements in performance and functions, so the locations monitored and the data width of signals for detecting faults have increased, and the scale of fault diagnosis circuits has increased. There is a problem that the number of design steps increases due to the increase in size, and the cost of the electronic circuit increases.
[0011]
Therefore, when identifying a failure part or predicting the occurrence itself, various abnormal states and failure states are fully understood, such as increasing the accuracy of identification and reducing the time loss until identification. Various attempts have been made on a method of implementing these configurations simply and at low cost.
[0012]
For example, Patent Literature 1 discloses a device that detects a magnetic field generated by a current flowing through an electronic circuit. The device proposed in Patent Literature 1 suppresses the influence of adjacent wiring on circuit wiring such as a printed circuit board or LSI mounted at high density and suppresses the magnetic field caused by the current of only one wiring at a high resolution and at a high resolution. It is measured by contact. By using such a device, it is possible to monitor the operation of the electronic circuit without providing a diagnostic circuit in advance in the electronic circuit for performing the failure diagnosis.
[0013]
[Patent Document 1]
JP-A-11-38111
[0014]
[Problems to be solved by the invention]
However, in the method described in Patent Document 1, although it is possible to sense a magnetic field generated from a state of a signal line on a circuit board and a current without contacting the same with high accuracy, it is expensive as a means for sensing the magnetic field. Since a dedicated probe (sensing probe) needs to be used, a failure detection cost is required.
[0015]
Further, in order to check the state of an arbitrary wiring or terminal of the sensing probe, it is necessary to bring the probe close to the vicinity and observe the state. This is because the range that can be detected by one probe is narrow, and it is necessary to bring the probe close to the diagnostic site for accurate diagnosis. Therefore, for example, as shown in FIG. 8, it is necessary to adopt a method of interposing a human hand as a means for bringing the probe closer to the target portion, or to move the probe using mechanical means. Therefore, it is difficult to measure the electronic circuit board in a state where the electronic circuit board is incorporated in a system such as an electronic device, and it is necessary to perform a fault diagnosis of the electronic circuit board offline, which requires a great deal of time and effort. In addition, it is difficult to fix the positional relationship between the probe and the inspection target site, and it is difficult to perform an accurate inspection.
[0016]
Further, in order to monitor the circuit operation in a plurality of arbitrary ranges, it is very expensive to incorporate a plurality of dedicated probes into the system and monitor the circuit operation over the entire electronic circuit board. On the other hand, when such a moving method is not adopted or when the number of built-in components is small, only the range near the probe position can be detected, and the detection range becomes very narrow.
[0017]
As described above, the conventional failure diagnosis method is not always easy to use in terms of cost and the degree of freedom in setting the target part of the failure diagnosis.
[0018]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a failure diagnosis method capable of realizing an easy-to-use failure diagnosis mechanism at low cost.
[0019]
Another object of the present invention is to provide a failure diagnosis system for implementing the failure diagnosis method of the present invention, and a printed wiring board used in the failure diagnosis system.
[0020]
[Means for Solving the Problems]
That is, the failure diagnosis method according to the present invention provides a magnetic field by passing a magnetic flux generated from a current flowing through a diagnosis target portion such as a wiring of a circuit board or the inside of a mounted component through a coil winding serving as a magnetic field sensing unit. Diagnosis of failure of wiring and mounted parts of circuit board by reading induced electromotive force generated in sensing part and comparing this read induced electromotive force with pre-measured induced electromotive force in normal state A diagnostic method, wherein a spiral coil as a magnetic field sensing unit is opposed to a diagnostic target portion, and a magnetic path length of the spiral coil is substantially equal to or less than a width of the diagnostic target portion, and further a diagnostic target portion is formed. It is arranged perpendicularly and fixedly to the flowing current direction.
[0021]
Here, as a specific mode as the “diagnosis target part”, for example, on a circuit board on which the failure diagnosis target part is mounted, the failure diagnosis target part itself, a terminal of the target part, or a terminal connected to the diagnosis target part. Wiring patterns, etc. are considered.
[0022]
When reading the induced electromotive force generated in the magnetic field sensing unit, either a mode of reading the induced electromotive voltage generated at the open end of the spiral coil or a mode of reading the current flowing through the spiral coil may be used.
[0023]
When the spiral coil is fixedly arranged at a position corresponding to the part to be diagnosed, the spiral coil may be formed by a printed wiring pattern on an outer layer (a front surface or a back surface) or an inner layer on the circuit board, or may be a cable member and a cable member. It may be formed by a fixing member for fixing a physical position.
[0024]
“To be fixedly arranged at a position corresponding to a diagnosis target part” means “one-to-one” for each diagnosis target part so as not to be affected by a magnetic field from another diagnosis target part. This means that the physical positional relationship between the coil windings and the target part for failure diagnosis is maintained in a constant state. For example, when applied to a device in which a circuit board and a coil winding are physically fixed, or an apparatus having a plurality of boards, a signal cable and a coil for providing a signal interface between a plurality of circuit boards. This is a state where the winding is physically fixed.
[0025]
The failure diagnosis system according to the present invention is a system that performs the failure diagnosis method according to the present invention, and is a coil that functions as a magnetic field sensing unit. A spiral coil whose path length is substantially the same as or less than the width of the diagnosis target part, and which is arranged perpendicularly and fixedly to the direction of the current flowing through the diagnosis target part, and a magnetic flux generated from the current flowing through the diagnosis target part The induced electromotive force generated in the magnetic field sensing unit is read by passing through the winding of the spiral coil that functions as a magnetic field sensing unit, and the read induced electromotive force is compared with the previously measured induced electromotive force in a normal state. And a failure diagnosis unit for diagnosing the presence / absence of a failure in the diagnosis target portion by comparing.
[0026]
The printed wiring board according to the present invention, in the board used in the failure diagnosis system according to the present invention, is a coil serving as a magnetic field sensing unit, facing the diagnosis target site, and a magnetic path of a spiral coil. The length is substantially the same as or less than the width of the diagnosis target portion, and a spiral coil is provided which is arranged perpendicularly and fixedly to the direction of current flowing through the diagnosis target portion.
[0027]
The dependent claims define further advantageous specific examples of the fault diagnosis system and the printed wiring board according to the present invention.
[0028]
[Action]
In the above configuration according to the present invention, first, the physical positional relationship between the coil winding and the diagnosis target portion is maintained in a one-to-one relationship with each diagnosis target portion. Thus, the spiral coil forming the magnetic field sensing unit is fixedly arranged. Then, an induced electromotive force generated in the magnetic field sensing unit is read by passing a magnetic flux generated from a current flowing through the wiring of the circuit board and the inside of the mounted component through a winding of a spiral coil serving as a magnetic field sensing unit. By comparing the induced electromotive force with the pre-measured induced electromotive force in a normal state, it is diagnosed whether or not the wiring of the circuit board or the mounted component has a failure.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0030]
FIG. 1 is a diagram for explaining a basic configuration and operation for realizing the present invention. Wiring is provided on the surface of a circuit board (printed board) 10 on which circuit components (not shown) such as passive components such as resistance elements, inductive elements, and capacitive elements, or active components such as transistors and ICs (Integrated Circuits) are mounted. A pattern 26 is formed. In the illustrated example, two wiring patterns 26a and 26b are arranged adjacent to each other at a predetermined interval.
[0031]
Although the wiring patterns 26a and 26b are mainly microstrip lines, a magnetic field shown in FIG. 1 is generated by a current flowing through the wiring. As shown in FIG. 1, a spiral coil (spiral-coiled inductor) 30 having a magnetic path length LEN substantially equal to the width PW of the wiring pattern is brought into non-contact proximity to one of the wiring patterns 26a, and It is arranged perpendicular to the direction of the current flowing through 26a.
[0032]
In this case, the magnetic field of the other wiring pattern 26b adjacent to the wiring pattern 26a to be inspected passes only through the spiral coil 30 having the coil diameter W because the distance is longer, and one of the wirings to be inspected is weaker. Only the magnetic field generated by the current of the pattern 26a efficiently passes through the spiral coil 30. Then, it becomes possible to monitor a change in current of only the wiring pattern 26 to be inspected by the induced electromotive force of the spiral coil 30.
[0033]
For example, assuming that a magnetic flux generated by a current flowing through the wiring pattern 26 and passing through the spiral coil 30 is Φ, an induced electromotive voltage V induced at both ends of the spiral coil 30 is obtained by Expression (1).
(Equation 1)

[0034]
Note that any device may be used as long as it reads the induced electromotive force generated in the spiral coil 30 as the magnetic field sensing unit, and is not limited to a mode in which the induced electromotive voltage generated at the open end of the spiral coil 30 is read as shown in Expression (1). Instead, a mode in which the current flowing through the spiral coil 30 is read may be adopted.
[0035]
In order to reduce the influence of the adjacent wiring, it is preferable to prevent the magnetic field from the wiring pattern 26b adjacent to the wiring pattern 26a to be inspected from passing through the spiral coil 30 as much as possible. For this purpose, it is preferable that the magnetic path length of the spiral coil 30 is substantially equal to or less than the width of a predetermined wiring pattern corresponding to a target part of the circuit board for failure diagnosis.
[0036]
Further, in order to perform an accurate inspection, it is desirable to fix a physical positional relationship between the wiring pattern 26a to be inspected and the spiral coil 30. When arranging the spiral coil 30 in a fixed manner with respect to a predetermined wiring pattern corresponding to the target part of the failure diagnosis, a printed wiring pattern may be formed on an outer layer (front surface or back surface) or an inner layer on the circuit board.
[0037]
Alternatively, a coil formed in advance by winding may be fixed substantially closely using a fixing member such as a taping member so as to be electrically non-contact. In this case, for example, after forming a coil in which the cross section of the opening of the magnetic path is substantially circular or elliptical, the coil is flattened, and the wiring pattern of the diagnosis target portion is placed at a position corresponding to the diagnosis target portion. And the flat surface of the coil may be fixedly arranged so as to face each other. This improves the stability of the arrangement.
[0038]
FIG. 2 is a diagram showing an example of a failure diagnosis system using the mechanism shown in FIG. Here, FIG. 2A is a diagram showing an outline of a failure diagnosis system together with a plan perspective view of the spiral coil 30 of the first example, and FIG. 2B is a diagram showing an XX line (through-hole) of FIG. FIG. 2C is a circuit symbol diagram of the spiral coil 30, and FIG. 2D is a block diagram illustrating a detailed example of a failure diagnosis unit 90 included in the failure diagnosis system 1. It is. The first terminal 31 and the second terminal 32 of the circuit symbol of FIG. 2C correspond to the first terminal 31 and the second terminal 32 of the plan perspective view of FIG.
[0039]
The failure diagnosis system 1 diagnoses the presence or absence of a signal failure in the wiring pattern 26 based on the spiral coil 30 arranged corresponding to the wiring pattern 26 to be inspected and the induced electromotive force detected by the spiral coil 30. And a failure diagnosis unit 90.
[0040]
As shown in FIG. 2B, the circuit board 10 has two insulators 37 stacked on each other, and the wiring pattern 26 is printed on the surface of one insulator 37a (on the right side in the figure). The spiral coil 30 of the first example is formed by the printed wiring patterns formed on both sides of the insulator 37b on the opposite side (the left side in the figure) facing the wiring pattern 26 with the insulator 37a interposed therebetween. . That is, the spiral coil 30 of the first example is formed on the same substrate as the circuit board (printed wiring board) 10 that constitutes the circuit.
[0041]
More specifically, the spiral coil 30 of the first example has a plurality of conductors (a plurality of first conductors 34 and a plurality of second conductors 35 each formed by cutting out a part of two opposing conductor layers). Are connected using a through hole (via hole) 36 in a predetermined order (to form a winding). An insulator 37c similar to the insulator 37b is arranged between the through holes 36.
[0042]
As shown in FIG. 2A, a failure diagnosis unit 90 for detecting the presence or absence of a failure in the circuit board 10 is connected to the first terminal 31 and the second terminal 32, which are the open ends of the spiral coil 30. It is supposed to be. The failure diagnosis unit 90 detects an induced electromotive force induced in the spiral coil 30 by a magnetic field generated in the wiring pattern 26 when power is supplied to the circuit board 10 and the circuit member operates. Then, the presence or absence of a failure in the circuit board 10 is diagnosed by comparing the induced electromotive force in the normal state (that is, the expected value) measured in advance with the induced electromotive force in the actual state. By providing the failure diagnosis unit 90 on the circuit board 10, a self-diagnosis system in which the apparatus itself diagnoses the board at the time of starting the apparatus may be constructed.
[0043]
As shown in FIG. 2D, the failure diagnosis unit 90 detects a induced electromotive force induced in the spiral coil 30 and amplifies the output to a predetermined level. A / D (Analog to Digital) converter 94 for converting the analog voltage into digital data, and a storage unit 96 such as a semiconductor memory for storing an induced electromotive force (expected value) induced in the spiral coil 30 in a normal state. A comparison / determination unit 98 that compares the expected value stored in the storage unit 96 with the induced electromotive force in the actual state to determine whether there is a failure, and a control unit 99 that controls the entire failure diagnosis system 1. I have.
[0044]
The induced electromotive force induced in the spiral coil 30 is amplified to a predetermined level by a buffer 92, and then converted into digital data by an A / D converter 94. For example, during normal operation, the control unit 99 takes in the induced electromotive force signal of the spiral coil 30 and stores it in the storage unit 96. The expected value may be obtained by performing feature extraction based on the induced electromotive force signal obtained by one measurement, or the average value detected a plurality of times may be used as the expected value.
[0045]
Next, the comparison / determination unit 98 actually operates the circuit and always takes in the induced electromotive force signal of the spiral coil 30 while following the instruction of the control unit 99 to store the normal waveform stored in the storage unit 96. Is constantly compared with the waveform that is always captured, and when there is a difference between the waveforms, it is determined that a failure has occurred in the wiring or mounted components of the circuit board. When a failure is detected, an alarm unit (not shown) issues an alarm (alarm) or notifies the user of the failure. The alarm unit may be provided inside the device having the failure diagnosis unit 90, or when the failure diagnosis unit 90 is located far away from the device to be diagnosed, the status of the device may be changed via a telephone line or the Internet. May be installed in a place where centralized management is performed, and an alarm may be issued there.
[0046]
It should be noted that, for example, by providing a feature amount extraction unit that analyzes the features of the read waveform and analyzing the change state of the waveform at the time of the failure in detail, it is possible to further identify the details of the failure. Further, the present invention is not limited to simple waveform comparison. For example, by providing a frequency analysis unit and performing a Fourier transform (not shown) on the read waveform to confirm a frequency value at which a peak occurs, the circuit board 10 It may be configured to analyze whether an abnormality has occurred.
[0047]
According to the configuration shown in FIG. 2, since the spiral coil 30 is formed by a printed wiring pattern, the spiral coil 30 functioning as a magnetic field sensing unit and the spiral coil 30 on the circuit board 10 are formed without using a special fixing member. It is possible to fix the physical positional relationship with the wiring pattern 26 that is the diagnosis target part. Thereby, the state of the induced electromotive force at the time of obtaining the expected value (at the time of normal operation) and during the failure diagnosis can be reliably stabilized. That is, the induced electromotive force, which is a judgment index for failure diagnosis, can be obtained with high accuracy, and the diagnostic performance is also improved.
[0048]
Further, since the spiral coil 30 is fixedly arranged by the printed wiring pattern, it is needless to say that there is no need for a mechanical means for bringing the probe closer to the diagnostic location for observation or for bringing the probe closer to the target portion. When a circuit board is manufactured, the spiral coil 30 for magnetic field sensing may be integrally patterned in accordance with a wiring pattern to be diagnosed (in a plurality of cases, each). It can be realized at low cost with little additional cost.
[0049]
This makes it possible to incorporate the magnetic field sensing unit into the system at low cost without adding a complicated failure diagnosis circuit to the electronic circuit even when monitoring the circuit operation in any multiple ranges, and to operate the circuit with high precision. Can be provided.
[0050]
FIG. 3 is a diagram illustrating a second example in which a spiral coil is formed on the same substrate as the circuit substrate 10 that forms the circuit. Here, FIG. 3A shows a spatial arrangement relationship between the spiral coil 50 and the wiring pattern 60 of the second example, FIG. 3B is a perspective plan view, and FIG. FIG. 4A is a cross-sectional perspective view of a spiral coil 50 portion of the XX line (through-hole portion) in FIG.
[0051]
As shown in FIG. 3C, the circuit board 10 includes a first wiring layer 61, a ground layer 65, a power supply layer 64, and a second wiring layer 62 which form a wiring pattern 60, in this order, an insulating layer. It is configured as a circuit board laminated with 67 interposed. Then, on the opposite side (upper side in the figure) of the first wiring layer 61 with the insulating layer 67 interposed therebetween, the spiral coil 50 of the second example is further laminated and patterned by a printed wiring pattern. I have.
[0052]
That is, the spiral coil 50 of the second example is also configured on the same substrate as the circuit substrate 10 configuring the circuit. More specifically, the spiral coil 50 of the second example has two coil layers (conductor layers) 51 and 52 and an insulating layer 57 added on the layer constituting the wiring pattern 60, and the first coil layer A plurality of first conductors 54 are formed on the 51 and a plurality of second conductors 55 are formed on the second coil layer 52.
[0053]
Then, the first conductor 54 and the second conductor 55 are connected in a predetermined order (to form a winding) by using the through holes 56, whereby the spiral coil 50 of the second example is formed. . Between the through holes 56 in the insulating layer 57, an insulator 57c similar to the insulating base material constituting the outer insulating layer 57 is arranged to constitute a part of the insulating layer 57.
[0054]
The spiral coil 50 is arranged on the wiring pattern 60 whose circuit operation is to be monitored (particularly, the wiring opposing the spiral coil 50 formed by the first conductor 74). As shown in), if the radial direction of the coil is W and the magnetic path length direction is LEN, the magnetic path length LEN is substantially the same as or smaller than the wiring width PW, thereby minimizing the influence of the magnetic flux of the adjacent wiring. In addition, the magnetic flux due to the target wiring can be detected efficiently.
[0055]
The distance between the first coil layer 51 and the second coil layer 52 depends on the thickness of the insulating layer 57, and is likely to be limited by the specifications of the substrate to be used (there is no degree of freedom in setting). , The pattern length of the first conductor 54 and the second conductor 55 (which is substantially equal to the distance between the through holes 56 at both ends). By increasing the coil diameter W, the magnetic flux passing through the spiral coil 50 increases. By adjusting the pattern length of the first conductor 54 and the second conductor 55 at the time of pattern design, the magnitude of the induced electromotive force can be increased. The coil diameter W can be adjusted accordingly.
[0056]
FIG. 4 is a diagram showing a third example of the spiral coil. Here, FIG. 4A is a diagram illustrating a spatial arrangement relationship between the spiral coil 70 and the wiring pattern 60 of the third example, and FIG. 4B is a diagram illustrating an XX line ( It is a cross-sectional perspective view of the spiral coil 70 part of a through-hole part).
[0057]
In the spiral coil 70 of the third example, the spiral coil 70 is formed on a substrate different from a printed wiring board 88 constituting a circuit, for example, an FPC (Flexible Printed Circuit) substrate 78 in the same manner as in the first example. Then, the FPC board 78 on which the spiral coil 70 is formed is arranged close to the printed wiring board 88.
[0058]
Specifically, the spiral coil 70 of the third example is provided with two coil layers (conductor layers) 71 and 72 and an insulating layer 77, and the first coil layer 71 has a first conductor 74 and a A plurality of second conductors 75 are pattern-formed on each of the second coil layers 72. Then, the spiral coil 70 of the third example is formed by connecting the first conductor 74 and the second conductor 75 in a predetermined order (to form a winding) using the through holes 76. .
[0059]
Between the through holes 76 in the insulating layer 77, an insulator 77c similar to the insulating base material forming the outer insulating layer 77 is arranged to form a part of the insulating layer 77. An insulating layer 77 is also formed on the surfaces of the two coil layers 71 and 72. As a base material constituting the insulating layer 77, a flexible plastic member (for example, polyimide or the like) is used.
[0060]
The printed wiring board 88 forming the circuit includes the first wiring layer 81, the ground layer 85, the power supply layer 84, and the wiring pattern 80, similarly to the wiring pattern 60 of the circuit board 10 shown in the second example. The second wiring layer 82 is configured as a circuit board laminated in this order with the insulating layer 867 interposed therebetween.
[0061]
The spiral coil 70 on the FPC board 78 is also configured so that the spiral coil 70 is arranged corresponding to the wiring pattern 80 (especially, the wiring in the first wiring layer 81) whose circuit operation is to be monitored, and the position is adjusted. And place them in close proximity.
[0062]
FIG. 5 is a diagram showing a fourth example of the spiral coil, and shows a cross-sectional perspective view of the spiral coil portion. The spiral coil 50 of the fourth example is a modification of the spiral coil 50 of the second example, and is arranged between two opposing coil layers (conductor layers) 51 and 52 that form the spiral coil 50. A structure in which a part of the insulating layer 57, specifically, the insulator 57 c disposed between the through holes 56 in the insulating layer 57 and the outside of the through hole 56 is replaced with an insulating magnetic layer 59. ing. In other words, the structure is such that an insulating magnetic material is arranged in a layer at a part between two opposing conductor layers (coil layers 51 and 52) used for forming the spiral coil 50.
[0063]
As a technique for arranging an insulating magnetic material in layers between two conductor layers, for example, a technique described in Japanese Patent Application Laid-Open No. 11-40915 may be used. For example, an insulating magnetic material may be used as the magnetic material forming the insulating magnetic layer 59. As the insulating magnetic material, for example, a mixture of Ni-Zn based ferrite fine powder, Mn-Zn based ferrite fine powder, Sendust fine powder, or Li based ferrite fine powder and an insulating solvent may be used. The insulating solvent includes an epoxy-based insulating solvent.
[0064]
In addition, as the insulating magnetic body disposed between the two coil layers 51 and 52, a metal foil having an insulating coating on both surfaces may be used. Metal foils with an insulating coating on both sides include an amorphous magnetic foil multilayer strip.
[0065]
Further, the entire insulating layer 57 may be replaced with the insulating magnetic layer 59 without being limited to the portion of the insulator 57c disposed between the through holes 56 in the insulating layer 57. In other words, a structure in which an insulating magnetic material is arranged in a layered manner over the entire area between two opposing conductor layers (coil layers 51 and 52) used to configure the spiral coil 50 may be employed.
[0066]
As described above, by disposing an insulating magnetic material in a part or the entire area between two opposing conductor layers (coil layers 51 and 52) used to configure the spiral coil 50, the spiral coil 50 is provided. Can be increased, the sensitivity of the spiral coil 50 can be improved, and a more accurate failure diagnosis system can be constructed.
[0067]
The mechanism of disposing the insulating magnetic layer as in the fourth example can be applied not only to the spiral coil 50 of the second example but also to other coils. For example, a part of the two coil layers 31 and 32 constituting the spiral coil 30 of the first example, that is, the insulator 37c disposed between the through holes 36, or the entire area between the layers is provided with an insulating magnetic material. Materials may be arranged. Similarly, a part between the two coil layers 71 and 72 constituting the spiral coil 70 of the third example, that is, the insulator 77c disposed between the through holes 76, or the entire area between the layers, A magnetic material may be provided.
[0068]
FIG. 6 is a diagram illustrating an example in which the failure diagnosis system 1 is applied to a circuit and a printed wiring board. Here, FIG. 6A shows an open-collector-type inverter circuit which inputs a digital signal Vin and causes a current Iout to flow through a resistance element 25 as a load resistance. FIG. 6B shows an example in which a spiral coil is arranged on a printed wiring board on which an inverter circuit is arranged, and FIG. 6C shows an example of a signal waveform when the inverter circuit is operated. FIG.
[0069]
As shown in FIG. 6A, the open-collector-type inverter circuit is configured such that a resistance element 25 is connected to an output of an open-collector inverter element 23 as a pull-up resistor. In the example shown in FIG. 6B, one terminal of a resistance element 25 is connected via a wiring pattern 26 to a terminal 24a of an inverter IC 24 in which a plurality of inverter elements 23 are arranged. The other terminal of the resistance element 25 is connected to a power supply (not shown) via a wiring pattern 26.
[0070]
Then, the spiral coil 30 of the first example, which has the wiring pattern 26 connected to the terminal 24a as a detection target, is disposed on the wiring pattern 26. Both ends of the spiral coil 30 are connected to a failure diagnosis unit 90 (not shown) (see FIG. 2D). The spiral coil 30 is not limited to the first example, but may be a second example to a fourth example.
[0071]
Here, when the input voltage Vin input to the inverter element 23 is at a low level, the output of the open collector type inverter element 23 is in a high impedance state, and the inverter element 23 pulled up by the resistance element 25 The output goes high. Then, when the input voltage Vin of the inverter element 23 changes from the low level to the high level, the output of the open collector type inverter element 23 changes to the low level, so that the current Iout flows through the resistance element 25.
[0072]
Since the amount of change in the current in the resistance element 25 is output as the induced electromotive force of the spiral coil 30, if the circuit is normal, the spiral coil 30 has a differential waveform as shown in FIG. Is output. On the other hand, for example, when the inverter element 23 is normal and the resistance element 25 fails and enters an open state (an example at the time of failure), as shown in FIG. Even if Vin transitions from the low level to the high level, no current flows through the resistance element 25, so that no induced electromotive force is output to the spiral coil 30.
[0073]
Therefore, the failure diagnosis unit 90 (not shown) can determine that there is a waveform difference in the comparison processing with the normal waveform that is always performed. That is, it is possible to detect that a failure has occurred in the circuit (the resistance element 25 in this example). In addition, it can be seen from the waveform at the time of failure shown in FIG. 6C-2 that the current Iout does not flow through the resistance element 25. Therefore, if the inverter element 23 is normal, an open failure of the resistance element 25 Can be identified.
[0074]
FIG. 7 is a diagram illustrating an example of a hardware configuration when a failure diagnosis system is configured as software using a CPU and a memory, that is, when a failure diagnosis system is configured using an electronic computer such as a personal computer. is there.
[0075]
The computer system 900 constituting the failure diagnosis unit 90 includes a CPU 902, a ROM (Read Only Memory) 904, a RAM 906, and a communication I / F (interface) 908. The RAM 906 includes an area for storing captured image data.
[0076]
In addition, recording / reading for reading / recording data from / to a storage medium such as a memory reading unit 907, a hard disk device 914, a flexible disk (FD) drive 916, or a CD-ROM (Compact Disk ROM) drive 918. An apparatus may be provided. Data is exchanged between each hardware through a data bus.
[0077]
The hard disk device 914, the FD drive 916, or the CD-ROM drive 918 is used, for example, for registering program data for causing the CPU 902 to perform software processing. Further, the hard disk device 914 includes an area for storing processing target data.
[0078]
The communication I / F 908 mediates the exchange of communication data with a communication network such as the Internet. Further, the computer system 900 includes an I / F unit 930 that functions as an interface with the circuit board 10.
[0079]
It should be noted that not all the processing of each functional part (particularly, the comparison and determination part 98) of the failure diagnosis unit 90 shown in the above-described embodiment is performed by software, but a part of these functional parts is implemented as a processing circuit 940 by hardware. It may be provided.
[0080]
The circuit board 10 is provided with an analog multiplexer 950, a buffer circuit 952, and an A / D conversion unit 954 as circuit members constituting a part of the failure diagnosis unit 90. For example, an analog multiplexer 950 is provided so as to correspond to a plurality of wiring patterns 26 as inspection target parts. The spiral coil 30 of the first example is arranged on each of the wiring patterns 26 to be inspected on the circuit board 10. The spiral coil 30 is not limited to the first example, but may be a second example to a fourth example.
[0081]
One terminal of each spiral coil 30 is commonly connected to the ground, and the other terminal is individually connected to a corresponding input terminal of the analog multiplexer 950. The selection operation of the analog multiplexer 950 is controlled by a control signal CNT from the I / F unit 930 on the computer system 900 side.
[0082]
An output signal of the analog multiplexer 950 is converted into digital data by an A / D converter 954 via a buffer circuit 952. The digital detection data output from the A / D conversion unit 954 is input to the I / F unit 930 of the computer system 900 via an output buffer (not shown).
[0083]
The computer system 900 having such a configuration can be the same as the basic configuration and operation of the failure diagnosis unit 90 shown in the above embodiment. Further, a program for causing a computer to execute the above-described processing is distributed through a recording medium such as a CD-ROM 922. Alternatively, the program may be stored in FD 920 instead of CD-ROM 922. Further, an MO drive may be provided, and the program may be stored in the MO, or the program may be stored in another recording medium such as a nonvolatile semiconductor memory card 924 such as a flash memory.
[0084]
Further, the program may be downloaded from another server or the like via a communication network such as the Internet, acquired, or updated. As a recording medium, in addition to the FD 920 and the CD-ROM 922, an optical recording medium such as a DVD, a magnetic recording medium such as an MD, a magneto-optical recording medium such as a PD, a tape medium, a magnetic recording medium, an IC card, A semiconductor memory such as a miniature card can be used.
[0085]
The FD 920, the CD-ROM 922, or the like as an example of the recording medium can store some or all of the functions of the processing in the failure diagnosis unit 90 described in the above embodiment. That is, the software installed in the RAM 906 or the like includes a functional unit such as the comparison / determination unit 98, the feature amount extraction unit, or the frequency analysis unit as software, like the failure diagnosis unit 90 described in the above embodiment. Such software may be stored in a portable storage medium such as a CD-ROM or FD as application software for failure monitoring, or distributed via a network.
[0086]
When the failure diagnosis unit 90 is configured by a computer, the CD-ROM drive 918 reads data or a program from the CD-ROM 922 and passes it to the CPU 902. Then, the software is installed from the CD-ROM 922 to the hard disk device 914. The hard disk device 914 stores the data or the program read by the FD drive 916 or the CD-ROM drive 918, the data created by the CPU 902 executing the program, and reads the stored data or the program to read the CPU 902. Pass to.
[0087]
The software stored in the hard disk device 914 is read by the RAM 906 and executed by the CPU 902. For example, the CPU 902 executes the above processing based on programs stored in the ROM 904 and the RAM 906, which are examples of a recording medium. For example, first, during normal operation, the induced electromotive force signal of the spiral coil 30 is fetched while being switched by the analog multiplexer 950, and stored in a storage device such as the hard disk device 914. Next, while the circuit is actually operated and the signal of the spiral coil 30 is constantly taken in, the normal waveform stored in the hard disk device 914 or the like is always compared with the always taken waveform according to the instruction of the CPU 902. Then, when a difference occurs in the waveform, it is determined that a failure has occurred, and an alarm is issued or details of the failure are notified. Further, by analyzing the change state of the waveform at the time of failure in detail, the details of the failure are identified in more detail.
[0088]
As described above, the present invention has been described using the embodiment. However, the technical scope of the present invention is not limited to the scope described in the embodiment. Various changes or improvements can be made to the above-described embodiment without departing from the spirit of the invention, and embodiments with such changes or improvements are also included in the technical scope of the present invention.
[0089]
Further, the above embodiments do not limit the invention according to the claims (claims), and all combinations of the features described in the embodiments are not necessarily essential to the means for solving the invention. Absent. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. Even if some components are deleted from all the components shown in the embodiment, as long as the effect is obtained, a configuration from which some components are deleted can be extracted as an invention.
[0090]
For example, in the spiral coils of the first to fourth examples shown in the above-described embodiment, the aspect in which the spiral coil is formed on the printed circuit board so as to correspond to the part to be diagnosed has been described. The method may be used. For example, as described in the description of FIG. 1, a coil formed in advance by winding may be fixed using a fixing member such as a taping member so as to be electrically non-contact.
[0091]
In the above-described embodiment, the wiring pattern connected to the diagnosis target component has been described as an example of the diagnosis target part. However, the failure diagnosis target part is not limited to the wiring pattern. For example, the terminal of the target component or the component itself may be used.
[0092]
【The invention's effect】
As described above, according to the present invention, since the spiral coil is fixedly arranged at a position facing each of the diagnosis target parts, the physical relationship between the spiral coil functioning as a magnetic field sensing unit and the diagnosis target part is established. Can be fixed. Thus, by stably stabilizing the state of the induced electromotive force at the time of obtaining the expected value (normal time) and during the failure diagnosis, it is possible to accurately acquire the induced electromotive force as a judgment index of the failure diagnosis, Diagnostic performance is improved.
[0093]
Also, the number of spiral coils to be installed can be set freely according to the target part of the failure diagnosis. For example, when monitoring circuit operations in a plurality of arbitrary ranges, it is easy to individually arrange spiral coils for the plurality of portions. This eliminates the need to incorporate a plurality of complex dedicated probes into the system or to move the probes in order to monitor the operation of the circuit in a plurality of arbitrary ranges.
[0094]
As described above, according to the present invention, a simple structure in which a spiral coil is appropriately installed according to the degree of a specific request for a failure diagnosis site is sufficient. In addition, this makes it possible to provide a user-friendly failure diagnosis mechanism in terms of cost and flexibility in setting a target part for failure diagnosis.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a basic configuration and operation of a spiral coil according to the present invention.
FIG. 2 is a diagram showing an example of a failure diagnosis system using the mechanism shown in FIG.
FIG. 3 is a diagram showing a second example in which a spiral coil is formed on the same substrate as a circuit substrate.
FIG. 4 is a diagram showing a third example of the spiral coil.
FIG. 5 is a diagram showing a fourth example of the spiral coil.
FIG. 6 is a diagram illustrating an example in which a failure diagnosis system is applied to a circuit and a printed wiring board.
FIG. 7 is a diagram illustrating an example of a hardware configuration when a failure diagnosis system is constructed using an electronic computer.
FIG. 8 is a diagram showing an outline of a mechanism for bringing a probe closer to a target site by intervening a human hand.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Failure diagnosis system, 10 ... Circuit board, 30, 50, 70 ... Spiral coil, 26, 60, 80 ... Wiring pattern, 59 ... Insulating magnetic material layer, 78 ... FPC board (flexible wiring board), 88 ... Print Wiring board, 90: Failure diagnosis unit

Claims (14)

The induced electromotive force generated in the magnetic field sensing unit is read by passing a magnetic flux generated from a current flowing through a diagnosis target site such as a wiring of a circuit board or the inside of a mounted component through a coil winding serving as a magnetic field sensing unit. By comparing the read induced electromotive force and the previously measured induced electromotive force in a normal state, a failure diagnosis method for diagnosing the presence or absence of a failure in the wiring and mounting components of the circuit board,
The spiral coil as the magnetic field sensing unit is opposed to the diagnostic target part, and the magnetic path length of the spiral coil is substantially equal to or less than the width of the diagnostic target part, and furthermore, the current direction flowing through the diagnostic target part A fault diagnosis method characterized in that the fault diagnosis method is arranged to be perpendicularly and fixedly arranged with respect to a vehicle. A failure diagnosis system for diagnosing the presence or absence of a failure in a diagnosis target portion such as a wiring of a circuit board or a mounted component,
A coil that functions as a magnetic field sensing unit, and faces the diagnosis target portion, and the magnetic path length of the spiral coil is substantially equal to or less than the width of the diagnosis target portion, and further includes the diagnosis target portion. A spiral coil arranged perpendicularly and fixedly to the flowing current direction,
The induced electromotive force generated in the magnetic field sensing unit is read by the magnetic flux generated from the current flowing through the diagnosis target portion passing through the winding of the spiral coil serving as the magnetic field sensing unit, and the read induced electromotive force is read. A failure diagnosis system, comprising: a failure diagnosis unit that diagnoses the presence or absence of a failure in the diagnosis target portion by comparing the electric power with a previously measured induced electromotive force in a normal state. The spiral coil includes a plurality of conductors formed by cutting a part of two opposing conductor layers formed by a printed wiring pattern on the circuit board, and a through-hole vertically connecting each of the plurality of conductors. It is composed of halls,
The failure diagnosis system according to claim 2, wherein the magnetic path length of the spiral coil is set to be substantially the same as or less than a predetermined wiring pattern corresponding to the diagnosis target part. The circuit board is a multilayer board formed by stacking a plurality of boards,
The failure diagnosis system according to claim 3, wherein the spiral coil is formed by a printed wiring pattern of two layers of the multilayer board. The spiral coil is formed on a printed wiring board different from the circuit board,
3. The failure diagnosis according to claim 2, wherein the printed wiring board on which the spiral coil is formed is arranged close to the circuit board so that the spiral coil and the diagnosis target portion face each other. system. The failure diagnosis system according to claim 5, wherein the printed wiring board on which the spiral coil is formed is a flexible wiring board. The failure diagnosis according to any one of claims 3 to 6, wherein an insulating magnetic material layer is provided between two conductor layers having conductors forming the spiral coil. system. The failure diagnosis system according to claim 2, wherein the circuit board includes a cable member that forms a winding of the spiral coil, and a fixing member that fixes a physical position of the cable member. . A printed wiring board used in the failure diagnosis system according to claim 2,
A coil that functions as a magnetic field sensing unit, and faces the diagnosis target portion, and the magnetic path length of the spiral coil is substantially equal to or less than the width of the diagnosis target portion, and further includes the diagnosis target portion. A printed wiring board, comprising: a spiral coil arranged perpendicularly and fixedly to a flowing current direction. The spiral coil includes a plurality of conductors formed by cutting a part of two opposing conductor layers formed by a printed wiring pattern on the circuit board, and a through-hole vertically connecting each of the plurality of conductors. It is composed of halls,
10. The printed wiring board according to claim 9, wherein a magnetic path length of the spiral coil is set to be substantially the same as or less than a predetermined wiring pattern corresponding to the diagnosis target part. A multilayer substrate formed by laminating a plurality of substrates,
11. The printed wiring board according to claim 10, wherein the spiral coil is formed by a two-layer printed wiring pattern forming the multilayer board. The printed wiring board according to claim 9, wherein the spiral coil is formed on a printed wiring board different from the circuit board. The printed wiring board according to claim 12, wherein the printed wiring board on which the spiral coil is formed is a flexible wiring board. The printed wiring according to any one of claims 9 to 13, wherein an insulating magnetic material layer is provided between two conductor layers having conductors forming the spiral coil. substrate.

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