JP3660496B2

JP3660496B2 - Method and apparatus for inspecting authenticity of coin

Info

Publication number: JP3660496B2
Application number: JP06037798A
Authority: JP
Inventors: 米▲蔵▼ 古矢
Original assignee: Nippon Conlux Co Ltd
Current assignee: Nippon Conlux Co Ltd
Priority date: 1998-02-26
Filing date: 1998-02-26
Publication date: 2005-06-15
Anticipated expiration: 2018-02-26
Also published as: MY123288A; KR20000076308A; JPH11250305A; CA2288297A1; AU2549499A; WO1999044176A1; EP0978807A4; AU729021B2; EP0978807A1; CA2288297C; KR100562857B1

Description

【０００１】
【発明の属する技術分野】
本発明はコインの真贋性を検査する方法及び装置に関し、特に自動販売機、ゲーム機器等に使用されるコインの検査装置及びその方法に関するものである。
【０００２】
【従来の技術】
近年コインの検査装置は、誘導コイルを用いた電子式が主流である。
この種のコイン検査装置は、一般的にコインの自由落下を利用するもので、コイン投入口から投入されたコインを案内する通路が設けられている。また、前記通路には複数組みの誘導コイルが配置されており、この各組みの誘導コイルにはそれぞれ異なる周波数により励磁される電磁場が設けられている。
【０００３】
コインの検査は、周知の原理によるもので、前記電磁場の中をコインが通過するとき、この電磁場とコインとの相互作用により得られる電気的変化量（周波数変化、電圧変化、位相変化）を検出してコインの真贋性を検査している。
従来技術におけるコイン検査装置は、コインの特徴は周波数に依存したパラメータが多いことから、米国特許第 3,870,137号が示すように、複数の周波数を使うことでコインの材質、外径、厚さなどを検査する技術として利用されてきた。
【０００４】
【発明が解決しようとする課題】
近年ボーダーレス化により諸外国のコインが容易に持ち込まれ、それらのコインが誤って或いは不正を試みる者による詐欺行為などのケースが増えている。それら諸外国のコインの中には材質、外径、厚さなどが近似するものがあり、例えば、米国の５ CENT 貨とパナマ国の５CENTESIMOS貨などはそれを代表する一例である。前記のような代表コインはコイン表面のデザイン( 凹凸模様) が異なるのみで材質、外径、厚さが殆ど一致している。従来技術のような誘導コイルの構成ではそのようなコインの表面の凹凸模様を複数の周波数を用いるのみでは微少な変化が検出できず、その結果前記のようなコインが判別できなかった。
【０００５】
また、日本の５００円硬貨と韓国の５００ウオン硬貨はその材質、外径がほぼ等しく、厚みが５００ウオン硬貨の方が僅か厚い。そのため、この５００ウオン硬貨を加工して、５００円硬貨として使用した場合、従来のコインの厚み、外形、材質でコインの真贋性を検査する方法では、この加工された５００ウオン硬貨と５００円硬貨を識別することは困難であった。
【０００６】
また従来技術では、前記のようなコインを判別する手段として画像処理などの光学的な方法が試みられてきた。しかし、光学的な装置は埃などが付着してコインの真偽判定を損ねる問題があり、装置が大きくなるばかりか複雑となりその結果高価となる問題があった。
本発明は上記課題に鑑みなされたもので、本発明の目的は、コイン表面の模様の差異によりコインを精度良く検査し識別するコイン検査方法及び装置を提供することにある。
【０００７】
【課題を解決するための手段】
本発明は、コイン通路の一側部の通路壁近傍に、励磁コイルと受信コイルを電磁的に結合するように配設し、コインが電磁界を通過することでコインの表面に生じる渦電流による反磁界の影響を前記受信コイルで検出されるような周波数での前記励磁コイルの励磁により、前記受信コイルで検出される起電力信号によってコインの凹凸模様の差異を検出する手段を設けることによりコインを識別しコインの真贋性を検査する。
【０００８】
コイン通路を通過するコイン表面と受信コイルを近接した方がよいことから、前記励磁コイル及び受信コイルが配設されたコイン通路の一側部の通路壁側に転動落下するコインが傾倒するようにコイン通路壁を形成する。また、材質によって、コイン内への電磁界の浸透が励磁周波数によって異なる。このことから、検出、識別対象のコインの材質に応じてコイン表面の凹凸模様の差異が受信コイルからの信号の差異としてよく現われる励磁周波数がある。そのため、前記励磁コイルを励磁する周波数は、識別対象のコインの材質によって選択設定するようにする。
【０００９】
具体的には、設定周波数を発振する発振回路手段と、発振回路手段の出力に接続された励磁駆動手段と、所定の角度で傾斜させたコイン通路に２つの磁極が向かうようにしてコイン通路の一側部の通路壁近傍に配置され、前記励磁駆動手段に接続された励磁コイルと、励磁コイルと電磁的に結合するようにして前記通路壁の近傍に配置した特性が略等しい２つの受信コイルと、前記励磁コイルと前記受信コイルとにより電磁場を構成し、前記受信コイルを含むようにして構成したブリッジ回路手段と、前記ブリッジ回路手段に接続された差動増幅手段と、前記差動増幅手段に接続された検波回路手段と、検波回路手段の出力に接続され、前記電磁場内に被検コインが作用したとき得られる信号に基づき該被検コインの特徴を検査し検査の結果と予め記憶されている所定金種の特徴とを比較し、前記信号が前記特徴に対し所定の許容範囲内にあるとき前記被検コインを真のものであるとする信号を出力する検査手段とを備えコインの真贋性を検査する。
【００１０】
【発明の実施の形態】
以下、図面により本発明の一実施形態を説明する。
図１および図２は本発明の一実施形態である。図１はコインの表面の凹凸模様を検出する検知コイルの構成を示す図で（ａ）は正面図、（ｂ）は断面図である。図２は同実施形態における回路の概略構成を示すブロック図である。
【００１１】
図１において、コイン表面の凹凸模様を検出する検知コイルは、１つの励磁コイル1 と２つの受信コイル２ａおよび２ｂで構成され、コイン通路６の一側部の通路壁７ａに配置されている。コイン通路６は、コイン３をガイドして落下させる所定角度で傾斜し、底部に配置されたコインレール４と、一対の通路壁７ａ，７ｂで構成され、通路壁７ａ，７ｂは図１（ｂ）に示すように、コイン３が一方の通路壁７ａ側に傾いて落下するように、コイン落下方向に垂直でかつ鉛直方向に対して傾いて配設されている。また、コインを載せガイドするコインレール４の表面も通過するコイン３が通路壁７ａ側に傾くように、通路壁７ａ，７ｂの傾斜方向に傾く構成となっている。
【００１２】
前記２つの受信コイルは図５（ｂ）に示すようにドラム型のコアーを有するもので、コインレール４の上方で、且つ２つの受信コイルのセンターを結ぶ線５ａがコインレール４と略平行になるようにして所定の間隔で配置されている。
一方、励磁コイル１は、図５（ａ）に示すように磁性材で構成されコの字型のコアーを有し、該コアーに巻回されたコイルで構成されている。該励磁コイル１は受信コイル２の上方に配置され、コアーの磁極面のセンターが前記所定の間隔で配置された受信コイル２ａと２ｂ間のセンターを結ぶ線５ｃとが略一致するようにして、かつコインレール４と略平行になるようにして配置されている。さらに、コアーの磁極面がコイン３の面と平行になるように配置されている。
【００１３】
前記のように配置した励磁コイル１と受信コイル２ａおよび２ｂは電磁的に結合するようにして電磁場を構成しいてる。
図２において、発振回路手段１１は、例えばＭＰＵ( マイクロプロセッサ・ユニット) 等で生成される設定された所定の周波数の方形波信号を出力端子へ出力する。前記発振回路手段１１の出力は、励磁駆動手段１２へ接続され、この励磁駆動手段１２の出力は、前記励磁コイル１へ接続され励磁コイル１を励磁駆動する。これにより励磁コイル１は前記励磁駆動手段１２の出力信号に応じて励磁コイル１の周辺に電磁界を発生する。
【００１４】
一方、前記のように構成される２つの受信コイル２ａおよび２ｂには、励磁コイル１の発する電磁界の強さに応じた起電力を生ずる。また前記で励磁コイル１と受信コイル２ａおよび２ｂはコイン３の表面が接近するようにして配置し検査する事が望ましい。
【００１５】
前記の如く構成した電磁場内にコイン３が作用するとき励磁コイル１により励磁されるコイン３の表面付近に渦電流が発生しその渦電流は作用周波数が高くなるのに伴って表皮効果によりコイン外周部付近で顕著な反磁界を発生する。前記現象によりコイン外周部の表面付近で発生した反磁界電流はコイン表面の僅かな形状的特徴変化を伴って受信コイル２ａおよび２ｂに相互作用する。受信コイル２ａおよび２ｂには前記コイン３の形状的特徴変化がもたらす反磁界電流の変化に応じた起電力（以下、この起電力を「検知信号」と称す）を生ずる。
さらに励磁コイル１の磁極が受信コイル２ａおよび２ｂの近傍に配置していることで、該磁極から発生する電磁界がコイン３に作用してもたらされる反磁界電流の変化を極近傍で捕らえることができる。
【００１６】
前記表皮効果による反磁界電流はコイン外周部付近で顕著に現れるが、コイン表面の凹凸が顕著である場合は特にコイン外周部付近に限定することなくその変化を検出することができる。この前記受信コイル２ａおよび２ｂの検知信号は、前記受信コイル２ａおよび２ｂを含むようにして構成したブリッジ回路手段１３により、前記検知信号に応じた交流電圧信号を生成し差動増幅手段１４へ出力する。差動増幅手段１４は前記ブリッジ回路手段１３で生成された交流電圧信号を増幅して検波回路手段１５へ出力する。検波回路手段１５は前記差動増幅手段１４で増幅された交流電圧信号を入力して、前記検知信号に対応する直流電圧信号を検査手段１６へ出力する。検査手段１６はその内部に有するＡＤ変換手段１７へ前記直流電圧信号を入力し対応する電圧のデジタル信号に変換し、同検査手段１６の内部に有する信号検査手段１８へ出力する。信号検査手段１８はコイン３が所定の特徴を備えているか否かを検査して検査の結果を出力端子１９へ出力する。前記信号検査手段１９の出力は後述する振り分けソレノイドや図示しないコインカウンター等を駆動するために使用される。
【００１７】
図３は、図２のブロック回路を具体的に示した詳細図である。図４はこの凹凸模様を検出する検知コイルを使用したコイン検査装置を示す正面図である。図５はコイルの構成を詳述する図で（ａ）は正面図、（ｂ）は断面図である。
図３で、図２のブロック図を対応させ回路構成を詳述すると、発振回路手段１１はＭＰＵ２０を用いてその内部の基準クロックを分周するようして接続された分周手段などを利用して構成している。励磁コイル１は、前記発振回路手段１１の出力する設定所定の周波数の近傍に共振するようにしてキャパシタＣ１と並列接続してＬＣ並列共振回路を構成している。
【００１８】
励磁駆動手段１２は、スイッチング動作を成すように接続したトランジスタＴＲ１と抵抗Ｒ３およびＲ４と、前記発振回路手段１１の出力する方形波を三角波に近似する波形にするための抵抗Ｒ５とキャパシタＣ４および抵抗Ｒ６とにより成る積分回路と、前記ＬＣ並列共振回路をなしている励磁コイル１に接続されたトランジスタＴＲ２と抵抗Ｒ７とによりなる駆動回路により構成されている。ブリッジ回路手段１３は、受信コイル２ａと並列接続するようにしたキャパシタＣ２と、受信コイル２ｂと並列接続するようにしたキャパシタＣ３と、抵抗Ｒ１およびＲ２とにより構成している。
【００１９】
作動増幅手段１４は、前記ブリッジ回路手段１３の出力に交流的にカップリングするようにして接続されるキャパシタＣ５およびＣ６と、演算増幅器Ａ１と、演算増幅器の利得を決定するようにして接続した抵抗Ｒ８、Ｒ１０およびＲ９、Ｒ１１とにより構成している。
検波回路手段１５は、前記作動増幅手段１４の出力に接続されたカップリング用キャパシタＣ７に接続されるダイオードＤ１とダイオードＤ２との整流回路（倍電圧整流回路）と、抵抗Ｒ１２とキャパシタＣ８とによる積分回路とにより成り、この検波回路手段１５を構成している。
【００２０】
検査手段１６のＡＤ変換手段１７および信号検査手段１８は、ＭＰＵ２０( マイクロプロセッサ・ユニット) を用いて構成している。
前記構成の発振回路手段１１は、設定された所定の周波数の方形波信号を出力するもので、その周波数は、コイン３の凹凸模様の差異を感度よく検出するために、電磁界がコインの凹凸模様の表面部に浸透し中心部まで浸透せず、渦電流による反磁界の影響が顕著に現れるような周波数が望ましい。この周波数は、判別対象コインの材質によって異なり、前述した米国の５ CENT 貨とパナマ国の５CENTESIMOS貨を識別する場合、これらの硬貨の材質は白銅であり、コインの材質が白銅の場合、励磁コイル１の励磁周波数は７０Ｋ（Ｈｚ）〜９０Ｋ（Ｈｚ）の周波数が望ましく、後述するこの発明による実験ではその周波数を９０Ｋ（Ｈｚ）にして行った。
【００２１】
この励磁コイル１を励磁する周波数の選択は、対象コインの材質によって決めるもので、同一外形で厚みのみを変えたコインに対して、励磁周波数を順次変えて受信コイル２ａ，２ｂで検出される電圧を測定し、コインの厚みの変化によって、検出電圧の変化が大きい周波数を求め、この周波数を励磁周波数とする。例えば、白銅の場合では、励磁周波数が７０Ｋ（Ｈｚ）〜９０Ｋ（Ｈｚ）程度が、厚みの変化に応じて検出電圧が一番大きく変化していることが実験によって求められた。この７０Ｋ（Ｈｚ）〜９０Ｋ（Ｈｚ）より高い周波数または低い周波数では、この周波数帯域より離れるに従ってコインの厚みの変化に対する検出電圧の変化が徐々に小さくなり、厚みの違いすなわちコイン表面の凹凸模様の違いによりコインを識別するには、白銅コインでは上述した７０Ｋ（Ｈｚ）〜９０Ｋ（Ｈｚ）の励磁周波数が適している。
【００２２】
また、例えは、対象コインの材質が黄銅であるような場合では、７Ｋ（Ｈｚ）〜１０Ｋ（Ｈｚ）程度の励磁周波数が、コインの厚みの変化による出力電圧の変化が大きい。そのため、黄銅で形成されたコインを表面の凹凸模様で識別するには、７Ｋ（Ｈｚ）〜１０Ｋ（Ｈｚ）の励磁周波数を用いると効率よくコインを識別できる。
【００２３】
前記構成の励磁駆動手段１２は、前記発振回路手段１１の出力する方形波信号を入力して、抵抗Ｒ５とキャパシタＣ４および抵抗Ｒ６とにより成る積分回路により、方形波を積分して三角波に近似する波形に変換して前記近似三角波信号により励磁コイル１を駆動している。励磁コイル１とキャパシタＣ１とによりなるＬＣ共振回路は前記周波数に共振して励磁コイル１の両端は結果として正弦波形で駆動される。
【００２４】
前記構成のブリッジ回路手段１３は、交流ブリッジ回路を構成するもので、受信コイル２ａと並列に接続されたキャパシタＣ２とによりなるインピーダンスをＺ１、受信コイル２ｂと並列に接続されたキャパシタＣ３とによりなるインピーダンスをＺ２、抵抗Ｒ１のインピーダンスをＺ３および抵抗Ｒ２のインピーダンスをＺ４とすると、交流ブリッジが平衡状態となる条件は、
Ｚ１・Ｚ４＝Ｚ２・Ｚ３
となる。
【００２５】
ここで、図３に示すようにブリッジ回路手段１３の出力は、受信コイル２ａと２ｂの接続点と、抵抗Ｒ１とＲ２の接続点との両接続点間に現れる信号であることから、いま受信コイル２ａの両端の電圧をＶ１、インピーダンスＺ１に流れる電流をｉ１、受信コイル２ｂの両端の電圧をＶ２、インピーダンスＺ２に流れる電流をｉ２とすると、前記両接続点間に現れる信号の電圧Ｖdef は次のようになる（但し抵抗Ｒ１のインピーダンスＺ３と抵抗Ｒ２のインピーダンスＺ４が等しいものとする）。
【００２６】
Ｖ１＝Ｚ１・ｉ１
Ｖ２＝Ｚ２・ｉ２
Ｖdef ＝Ｖ１−Ｖ２
Ｖdef ＝Ｚ１・ｉ１−Ｚ２・ｉ２
この実施形態では、受信コイル２ａとキャパシタＣ２とによるＬＣ共振回路の共振周波数と、受信コイル２ｂとキャパシタＣ３とによるＬＣ共振回路の共振周波数が前記発振回路手段１１が出力する発振周波数に略等しくなるようにしていることから、インピーダンスＺ１とＺ２は略等しくなり前記両接続点間に現れる信号の電圧は電流ｉ１とｉ２との差によってもたらされる電圧信号となる。
【００２７】
前記構成の作動増幅手段１４は、前記ブリッジ回路手段１３の出力する交流電圧の信号を入力して所望の交流電圧信号に増幅して検波回路手段１５へ出力する。
【００２８】
前記構成の検波回路手段１５は、前記差動増幅手段１４の出力する交流電圧信号を入力してダイオードＤ１により検波整流を行って、抵抗Ｒ１２およびキャパシタＣ８により構成される積分回路により前記ブリッジ回路手段１３の出力に対応する直流電圧信号に変換する。
前記構成のＡＤ変換手段１７は、ＭＰＵ２０に内蔵されている例えば分解能８ビットの逐次比較変換形のＡＤ変換器を用いて実現している。ＡＤ変換手段１７は、検波回路手段１５の出力するアナログの直流電圧信号を入力して、所定の間隔でサンプリングを行い、ブリッジ回路手段１３の出力に対応するデジタル信号に変換しデジタル信号列を信号検査手段１８へ出力する。
【００２９】
前記構成の信号検査手段１８は、ＡＤ変換手段１７の出力する振幅軸上のデジタル信号列を入力してこれをＲＡＭなどのメモリ手段に一時記憶保持し、前記ＲＡＭ内に一時記憶保持したデジタル信号列と、予めメモリ手段２１に記憶保持されている当該金種のデータ列との統計値を求め、前記統計値が予めメモリ手段２１に記憶保持されている所定値と比較して所定の特徴を備えているか否かを検査し検査の結果を出力端子１９へ出力する。
前記統計値を求める具体的な方法として相関係数を求めるつぎの式を用いることができる。
【００３０】
【数１】

上の１式で、Ｎはサンプリング数、変数Ｘｉはサンプリング値で被検コインを測定して得られる前記デジタル信号列の値、変数Ｙｉは受納可能金種をこの発明の装置を用いて予めサンプリング測定して求めた統計的な値である。また、Ｘａ、Ｙａはそれぞれの平均値である。
ＭＰＵの処理速度を考慮するならば、前記１式において分子の偏差クロス積和の中の受納可能金種のサンプリング値Ｙｉとその平均値Ｙａとの偏差値（Ｙｉ−Ｙａ）、および１式の分母のサンプリング値Ｙｉとその平均値Ｙａの偏差の平方和の平方根について予め計算し、その値をメモリ手段21へ記憶させておくことで、後の処理速度を格段に速めることが可能となる。
【００３１】
ここで、１式により求めた相関係数ｒの絶対値は周知のように０≦｜ｒ｜≦１の範囲をとることから、この相関係数ｒと予め記憶された所定値と比較することで被検コインが所定の特徴を備えているか否かを検査することができ、前記係数ｒが限りなく「１」に近いとき被検コインは受納可能金種のコインに対し真であると判定することができる。しかし、検査の結果前記係数が限りなく零に近いときはそのコインを偽として判定することができる。そのため、真偽判別の前記所定値を判別しようとする対象コインに合わせて１以下の１に近い値を設定しておき、該設定値よりも大きい相関係数ｒが得られたときには、正貨のコインと判別する。
【００３２】
ここで、この発明の装置で測定した代表コインの特性について図６および図７を用いて述べる。図６は代表コインの特性を示す図である。図７は代表コインの諸元を示す対比図である。図７で、代表コインの米国５CENT貨とパナマ国の５CENTESIMOS貨は、材質（白銅）、直径、厚さが殆ど近似するコインである。前記コインを目視的に見るならば両コインの違いはそのコインの表面のデザインが異なるのみである。
【００３３】
図６はこの発明による装置を用いて、励磁周波数を９０Ｋ（Ｈｚ）にして励磁コイル１を励磁して、前記コインを測定した結果を示す特性図である。図６で、符号５０（太い線で示す）は米国５CENT貨のもので、符号５１はパナマ国の５CENTESIMOS貨のそれである。同図から前記両コインの特性の違いは最初のピークと最後のピークに現れている様子が判る。これは、コイン表面に発生する渦電流がコイン表面の模様の凹凸に特徴づけられた反磁界を発生し、それにより前記２つの受信コイルのそれぞれに発生する起電力の僅かな差を検出できることに他ならない。従来技術においては前記のような違いを検出することができなかった。次に図４および図２を用いてコインの真贋性を検査する装置３０の動作について詳述する。
【００３４】
図４で、コインの真贋性を検査する装置３０はコイン投入口３１から投入されたコイン３を自然落下によって、コイン投入口３１の下方に設けたコインレール４へ落下させる。コインレール４へ落下したコイン３は、コイン通路６（図１（ｂ））を通ってコイン投入口３１から遠ざかる方向の下流に転動しながら落下する。コイン３はコイン通路６内を移動する間外径検知コイル３２、材質検知コイル３３、凹凸模様検知コイルの励磁コイル１および受信コイル２ａ，２ｂを通過する。装置３０はコイン３が前記各検知コイルを通過する間コイン３の真贋性を検査する。前記検査の結果コイン３が真正であると判定したときは、出力端子１９へ出力される信号に基づき振り分けソレノイド３５を駆動してゲード３４を作動させて、コイン３を図示しない正貨通路へ導く。しかし、検査の結果コイン３が偽貨と判定されたときはゲート３４を作動せずにコイン３を図示しない偽貨通路へ導き、図示しない排出口より排出する。
【００３５】
ここではコイン３が正貨であると仮定すると、正貨通路へ導かれたコイン３は自由落下を続け、やがてコインレール３６へ落下する。コインレール３６へ落下したコイン３は図示しない周知の振り分け手段により金種毎に振り分けられ各金種毎に設けられた排出口Ａ、Ｂ、Ｃ、Ｄの対応する排出口より排出される。
前記で外径検知コイル３２および材質検知コイル３３の検査手段は周知の技術を用いることができる。
【００３６】
ここで、図８のフローチャートを用いて凹凸模様を検出する検知コイルによるコインの真贋性を検査する装置３０の動作を詳述する。図８で、装置は電源が投入されるとステップ１００でＭＰＵ２０内の入出力などの初期設定を行う。ステップ１００を実行後、ステップ１０１の判断処理で検知コイルの信号を用いて装置内にコインが投入されたか否かを判断する処理を実行する。ステップ１０１の判断処理でコインが投入されたと判断すると、プログラムはステップ１０２のＡＤ変換処理へと進む。しかし、ステップ１０１の判断処理でコインが投入されていないと判断するとコインの到来を待つようにして待機処理をループする。
【００３７】
ステップ１０１の判断処理でコインが投入されたと判断すると、ステップ１０２のＡＤ変換処理へ進む。ステップ１０２のＡＤ変換処理はコインが検知コイル内に到来するとその信号を受けて、凹凸模様を検出する検知コイルの受信コイル２ａ，２ｂからの信号である検波回路手段１５の出力信号のサンプリングを開始する。サンプリング結果はＭＰＵ２０内のＲＡＭなどのメモリ手段に一時記憶保持してステップ１０３の演算処理へ進む。
【００３８】
ステップ１０３の演算処理は、前記メモリ手段に一時記憶保持されたデジタル信号列の値と予めメモリ手段２１に記憶されている受納可能コインの統計値とを前記１式を使って相関係数ｒを求める処理を行って、ステップ１０５の真偽判定へ進む。
ステップ１０５の真偽判定は、前記ステップ１０３の演算処理により求めた相関係数と予め記憶させた受納可能コインの所定値とを比較し、相関係数ｒ＞所定値のとき被検コインを真のものであると判定し、ステップ１０６の正貨処理へと進む。しかし、相関係数ｒ＜所定値と判定したときは被検コインを偽と判定し、ステップ１０４の偽貨処理を実行して待機ループへ戻る。
【００３９】
ここでは、ステップ１０５の真偽判定処理で被検コインが真のものであると判定されたものと仮定してステップ１０６の正貨処理を実行するものとする。ステップ１０６の正貨処理は、前記判定結果に基づき正貨信号、金種信号などを出力する処理を実行し待機ループへ戻る。
図９は、本発明の第２の実施形態の凹凸模様を検出する検知コイルの構成を示す図である。上述した第１の実施形態と相違する点は、励磁コイル１のコの字型のコアーの長て方向のコアーの磁極面のセンターを結ぶ線５ｂが受信コイル２ａ，２ｂのセンターを結ぶ線５ａと直交し、前記線５ｂは受信コイル２ａ，２ｂの中間点を通るように励磁コイル１及び受信コイル２ａ，２ｂを配設している点のみである。作用及び効果は第１の実施形態と同様なのでその説明を省略する。
【００４０】
図１０は、本発明の第３の実施形態の凹凸模様を検出する検知コイルの構成を示す図である。上述した第１の実施形態と相違する点は、受信コイル２ａ，２ｂのセンターを結ぶ線５ａが、コイン３が転動落下するコインレール４に対して垂直方向にシフトし、対象とするコイン３の中心部位置を通るようにしている点において相違するのみである。この第３の実施形態の場合、受信コイル２ａ，２ｂが対象コイン３の中心部に配置されているから、コイン３の中心部の凹凸模様の差異によって検出値が異なることになり、コインの中心に穴があるかないかのコインの真偽識別に適している。
【００４１】
図１１は、本発明の第４の実施形態の凹凸模様を検出する検知コイルの構成を示す図である。上述した第１の実施形態と相違する点は、受信コイルの配列を９０度回転させ、受信コイル２ａ，２ｂのセンターを結ぶ線５ａが励磁コイル１のコアーの磁極面のセンターを結ぶ線５ｂと直交し、該励磁コイル１の中心部で交差するように構成した点である。この第４の実施形態も、受信コイル２ａ，２ｂが対象コインの中心部に対応する位置に配置されることから、コインの中央部に凹凸模様の変化があるコイン、ないコインに対して真偽判別する場合にこの第４の実施形態は適している。
【００４２】
以上のように、受信コイル２ａ，２ｂの配設位置（この受信コイルの配設位置に対応して励磁コイルの配設位置）は、真偽を判別しようとする対象コインの表面の凹凸模様の差異に応じて（中心部に穴のあるなしによる凹凸模様に差異がある場合、コインの周辺部に凹凸模様の差異がある場合等）、変えればよいものである。
また、本発明は、電磁界がコインの表面のみ浸透し、中心部まで浸透しないような周波数で励磁コイル１を励磁して電磁界を形成し、コイン表面付近で発生する渦電流による反磁界の影響を測定するものであるから、受信コイル２ａ，２ｂのコインに対向する面は、コイン表面に近接する程望ましい。
【００４３】
そこで、図１２に示すように、通路壁７ａの受信コイル２ａ，２ｂが配設された位置、即ち、図１で受信コイル２ａ，２ｂのセンターを結ぶ線５ａに沿って、受信コイル２ａ，２ｂが配設された位置を透磁率の高い材質２００で形成することによって、受信コイル２ａ，２ｂをコイン表面に実質的に近接させた状態を形成するようにしてもよい。
なお、上述した各実施形態では、励磁コイル１をコの字形のコアーを用いて示したが、Ｕの字形などこの発明による要旨を逸脱しない範囲において適宜他の形状のものを用いてもよい。
【００４４】
【発明の効果】
本発明によれば、コイン表面の凹凸模様が検出できるので多用なコインに対し小型で高性能なコイン検査装置を安価に提供することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態における凹凸模様を検出する検知コイルの構成を示す図で（ａ）は正面図、（ｂ）は断面図である。
【図２】本発明の実施形態における回路の概略ブロック図である。
【図３】同実施形態における回路の具体図である。
【図４】本発明の一実施形態におけるコインの真贋性を検査する装置を示す正面図である。
【図５】本発明の実施形態におけるコイルの構成を詳述する図（ａ）は正面図、図（ｂ）は断面図である。
【図６】本発明の実施形態における代表コインの特性を示す特性図である。
【図７】本発明の実施形態における代表コインの諸元を示す対比図である。
【図８】本発明の実施形態における動作のフローチャート図である。
【図９】本発明の第２の実施形態における凹凸模様を検出する検知コイルの構成を示す図で（ａ）は正面図、（ｂ）は断面図である。
【図１０】本発明の第３の実施形態における凹凸模様を検出する検知コイルの構成を示す図で（ａ）は正面図、（ｂ）は断面図である。
【図１１】本発明の第４の実施形態における凹凸模様を検出する検知コイルの構成を示す図で（ａ）は正面図、（ｂ）は断面図である。
【図１２】本発明の各実施形態において受信コイルを配置したコイン通路壁の部分を透磁率の高い材料で構成した例を示す説明図である。
【符号の説明】
１励磁コイル
２ａ，２ｂ受信コイル
３コイン
４コインレール
６コイン通路
７ａ，７ｂコイン通路の通路壁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for inspecting the authenticity of a coin, and more particularly to an apparatus and method for inspecting a coin used in a vending machine, a game machine and the like.
[0002]
[Prior art]
In recent years, an electronic type using an induction coil has been the mainstream of coin inspection devices.
This type of coin inspection device generally uses free fall of coins, and is provided with a passage for guiding coins inserted from a coin insertion slot. A plurality of sets of induction coils are disposed in the passage, and each set of induction coils is provided with an electromagnetic field excited by a different frequency.
[0003]
The coin inspection is based on a well-known principle, and when a coin passes through the electromagnetic field, an electrical change amount (frequency change, voltage change, phase change) obtained by the interaction between the electromagnetic field and the coin is detected. And the authenticity of the coin is inspected.
Since the coin inspection device in the prior art has many parameters depending on the frequency, the coin's material, outer diameter, thickness, etc. can be determined by using multiple frequencies as shown in US Pat. No. 3,870,137. It has been used as an inspection technique.
[0004]
[Problems to be solved by the invention]
In recent years, coins from other countries have been easily brought in by borderlessization, and cases of fraudulent acts by those who try to make mistakes or frauds are increasing. Some of these foreign coins are similar in material, outer diameter, thickness, etc. For example, the US 5 CENT and Panama 5 CENTESIMOS coins are representative examples. The representative coins as described above have almost the same material, outer diameter, and thickness except for the design (uneven pattern) on the coin surface. In the configuration of the induction coil as in the prior art, a minute change cannot be detected only by using a plurality of frequencies on the concave / convex pattern on the surface of such a coin, and as a result, such a coin cannot be identified.
[0005]
Japanese 500 yen coins and Korean 500 won coins are almost the same in material and outer diameter, and 500 won coins are slightly thicker. Therefore, when this 500 won coin is processed and used as a 500-yen coin, the conventional 500-in coin and 500-yen coin are used in the conventional method for inspecting the authenticity of the coin with the thickness, shape and material of the coin. It was difficult to identify.
[0006]
In the prior art, an optical method such as image processing has been tried as means for discriminating coins as described above. However, the optical device has a problem that dust or the like adheres to it, and the true / false judgment of the coin is impaired, and there is a problem that the device becomes large as well as becomes complicated and consequently expensive.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a coin inspection method and apparatus for accurately inspecting and identifying a coin based on a difference in pattern on the coin surface.
[0007]
[Means for Solving the Problems]
In the present invention, an exciting coil and a receiving coil are disposed in the vicinity of a passage wall on one side of a coin passage so as to be electromagnetically coupled, and the eddy current generated on the surface of the coin when the coin passes through an electromagnetic field. By providing means for detecting a difference in the concave / convex pattern of the coin based on an electromotive force signal detected by the receiving coil by exciting the exciting coil at a frequency at which an influence of a demagnetizing field is detected by the receiving coil. And verify the authenticity of the coin.
[0008]
Since the coin surface passing through the coin passage and the receiving coil should be close to each other, the coin rolling and falling to the passage wall side of one side of the coin passage where the exciting coil and the receiving coil are disposed tilts. Form a coin passage wall. Further, the penetration of the electromagnetic field into the coin depends on the excitation frequency depending on the material. Therefore, there is an excitation frequency in which a difference in the uneven pattern on the coin surface often appears as a difference in the signal from the receiving coil depending on the material of the coin to be detected and identified. Therefore, the frequency for exciting the exciting coil is selected and set according to the material of the coin to be identified.
[0009]
Specifically, the oscillation circuit means for oscillating the set frequency, the excitation drive means connected to the output of the oscillation circuit means, and the two magnetic poles are directed to the coin path inclined at a predetermined angle. An excitation coil disposed near the passage wall on one side and connected to the excitation drive means, and two reception coils having substantially the same characteristics disposed near the passage wall so as to be electromagnetically coupled to the excitation coil The excitation coil and the receiving coil constitute an electromagnetic field, the bridge circuit means configured to include the receiving coil, the differential amplifying means connected to the bridge circuit means, and the differential amplifying means Detection circuit means, connected to the output of the detection circuit means, and based on a signal obtained when the test coin acts in the electromagnetic field, the characteristics of the test coin are inspected and the result of the inspection A test means for comparing a characteristic of a predetermined denomination stored in advance and outputting a signal indicating that the test coin is true when the signal is within a predetermined allowable range with respect to the characteristic; Check the authenticity of prepared coins.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 show an embodiment of the present invention. 1A and 1B are diagrams showing a configuration of a detection coil for detecting a concavo-convex pattern on the surface of a coin. FIG. 1A is a front view, and FIG. 1B is a cross-sectional view. FIG. 2 is a block diagram showing a schematic configuration of a circuit in the same embodiment.
[0011]
In FIG. 1, the detection coil for detecting the uneven pattern on the coin surface is composed of one excitation coil 1 and two

reception coils

2 a and 2 b, and is arranged on the passage wall 7 a on one side of the coin passage 6. The coin passage 6 is inclined at a predetermined angle to guide and drop the coin 3, and is composed of a coin rail 4 disposed at the bottom and a pair of

passage walls

7a and 7b. The

passage walls

7a and 7b are shown in FIG. ), The coin 3 is disposed perpendicular to the coin dropping direction and inclined with respect to the vertical direction so that the coin 3 is inclined and dropped toward the one passage wall 7a. Further, the coin 3 passing through the surface of the coin rail 4 for placing and guiding the coin is inclined in the inclination direction of the

passage walls

7a and 7b so that the coin 3 passing through the surface is inclined toward the passage wall 7a.
[0012]
The two receiving coils have a drum-shaped core as shown in FIG. 5B, and a line 5a connecting the centers of the two receiving coils is substantially parallel to the coin rail 4 above the coin rail 4. In this way, they are arranged at a predetermined interval.
On the other hand, as shown in FIG. 5A, the exciting coil 1 has a U-shaped core made of a magnetic material, and is formed of a coil wound around the core. The exciting coil 1 is arranged above the receiving coil 2 so that the center of the magnetic pole surface of the core substantially coincides with the line 5c connecting the centers between the receiving

coils

2a and 2b arranged at the predetermined interval, And it is arranged so as to be substantially parallel to the coin rail 4. Further, the magnetic pole surface of the core is arranged so as to be parallel to the surface of the coin 3.
[0013]
The exciting coil 1 and the receiving

coils

2a and 2b arranged as described above are electromagnetically coupled to form an electromagnetic field.
In FIG. 2, an oscillation circuit means 11 outputs a square wave signal having a predetermined frequency set by an MPU (microprocessor unit) or the like to an output terminal. The output of the oscillation circuit means 11 is connected to the excitation drive means 12, and the output of the excitation drive means 12 is connected to the excitation coil 1 to excite the excitation coil 1. As a result, the excitation coil 1 generates an electromagnetic field around the excitation coil 1 in accordance with the output signal of the excitation drive means 12.
[0014]
On the other hand, an electromotive force corresponding to the strength of the electromagnetic field generated by the exciting coil 1 is generated in the two receiving

coils

2a and 2b configured as described above. In addition, it is desirable that the exciting coil 1 and the receiving

coils

2a and 2b are arranged and inspected so that the surface of the coin 3 approaches.
[0015]
When the coin 3 acts in the electromagnetic field constructed as described above, an eddy current is generated in the vicinity of the surface of the coin 3 excited by the exciting coil 1, and the eddy current is increased by the skin effect as the operating frequency increases. A significant demagnetizing field is generated near the area. The demagnetizing field current generated in the vicinity of the outer surface of the coin due to the above phenomenon interacts with the receiving

coils

2a and 2b with a slight change in the shape of the coin surface. In the receiving

coils

2a and 2b, an electromotive force (hereinafter, this electromotive force is referred to as “detection signal”) corresponding to the change in the demagnetizing field current caused by the change in the shape characteristic of the coin 3 is generated.
Furthermore, since the magnetic pole of the exciting coil 1 is arranged in the vicinity of the receiving

coils

2a and 2b, the change in the demagnetizing current caused by the electromagnetic field generated from the magnetic pole acting on the coin 3 can be captured in the vicinity of the pole. it can.
[0016]
The demagnetizing field current due to the skin effect appears remarkably in the vicinity of the outer periphery of the coin. However, when the unevenness on the coin surface is significant, the change can be detected without being limited to the vicinity of the outer periphery of the coin. The detection signals of the reception coils 2a and 2b are generated by the bridge circuit means 13 configured to include the reception coils 2a and 2b, and an AC voltage signal corresponding to the detection signal is generated and output to the differential amplification means 14. The differential amplifying means 14 amplifies the AC voltage signal generated by the bridge circuit means 13 and outputs it to the detection circuit means 15. The detection circuit means 15 receives the AC voltage signal amplified by the differential amplification means 14 and outputs a DC voltage signal corresponding to the detection signal to the inspection means 16. The inspection unit 16 inputs the DC voltage signal to the AD conversion unit 17 included therein, converts the DC voltage signal into a digital signal having a corresponding voltage, and outputs the digital signal to the signal inspection unit 18 included in the inspection unit 16. The signal inspection means 18 inspects whether or not the coin 3 has a predetermined characteristic and outputs the inspection result to the output terminal 19. The output of the signal inspection means 19 is used to drive a sorting solenoid, a coin counter (not shown), etc., which will be described later.
[0017]
FIG. 3 is a detailed diagram specifically showing the block circuit of FIG. FIG. 4 is a front view showing a coin inspection device using a detection coil for detecting the uneven pattern. 5A and 5B are diagrams for explaining the configuration of the coil in detail. FIG. 5A is a front view, and FIG. 5B is a cross-sectional view.
3, the circuit configuration will be described in detail with reference to the block diagram of FIG. 2. The oscillation circuit means 11 uses the dividing means connected so as to divide the internal reference clock using the MPU 20. Is configured. The exciting coil 1 is connected in parallel with the capacitor C1 so as to resonate in the vicinity of a set predetermined frequency output from the oscillation circuit means 11, thereby constituting an LC parallel resonance circuit.
[0018]
The excitation drive means 12 includes a transistor TR1 and resistors R3 and R4 that are connected so as to perform a switching operation, a resistor R5, a capacitor C4, and a resistor for making the square wave output from the oscillation circuit means 11 a waveform that approximates a triangular wave. The driving circuit is composed of an integrating circuit composed of R6 and a transistor TR2 connected to the exciting coil 1 constituting the LC parallel resonant circuit and a resistor R7. The bridge circuit means 13 includes a capacitor C2 that is connected in parallel to the receiving coil 2a, a capacitor C3 that is connected in parallel to the receiving coil 2b, and resistors R1 and R2.
[0019]
The operational amplifying means 14 includes capacitors C5 and C6 connected so as to be AC-coupled to the output of the bridge circuit means 13, an operational amplifier A1, and a resistor connected so as to determine the gain of the operational amplifier. R8, R10 and R9, R11.
The detection circuit means 15 includes a rectifier circuit (double voltage rectifier circuit) of a diode D1 and a diode D2 connected to a coupling capacitor C7 connected to the output of the operation amplifier means 14, a resistor R12, and a capacitor C8. The detection circuit means 15 is constituted by an integration circuit.
[0020]
The AD conversion means 17 and the signal inspection means 18 of the inspection means 16 are configured using an MPU 20 (microprocessor unit).
The oscillating circuit means 11 configured as described above outputs a square wave signal having a set predetermined frequency. The frequency of the oscillating circuit means 11 is such that the electromagnetic field is uneven in order to detect a difference in the uneven pattern of the coin 3 with high sensitivity. It is desirable to use a frequency that penetrates the surface portion of the pattern and does not penetrate to the center portion, and the influence of the demagnetizing field due to the eddy current appears remarkably. This frequency varies depending on the material of the coins to be discriminated. When the above-mentioned US 5 CENT and Panama 5 CENTESIMOS coins are identified, the material of these coins is bronze, and when the coin is bronze, the excitation coil The excitation frequency 1 is desirably a frequency of 70 K (Hz) to 90 K (Hz). In the experiment according to the present invention described later, the frequency was set to 90 K (Hz).
[0021]
The selection of the frequency for exciting the exciting coil 1 is determined by the material of the target coin, and the voltage detected by the receiving

coils

2a and 2b by sequentially changing the exciting frequency for coins having the same outer shape and only the thickness changed. , And a frequency with a large change in the detection voltage is obtained by a change in the thickness of the coin, and this frequency is set as an excitation frequency. For example, in the case of white copper, it has been experimentally determined that the detection voltage changes most greatly in accordance with the change in thickness when the excitation frequency is about 70 K (Hz) to 90 K (Hz). At a frequency higher or lower than 70 K (Hz) to 90 K (Hz), the change in the detection voltage with respect to the change in the coin thickness gradually decreases as the distance from the frequency band increases. In order to identify a coin by the difference, the excitation frequency of 70 K (Hz) to 90 K (Hz) described above is suitable for a white copper coin.
[0022]
For example, when the material of the target coin is brass, an excitation frequency of about 7 K (Hz) to 10 K (Hz) has a large change in output voltage due to a change in coin thickness. Therefore, in order to identify the coin formed of brass by the uneven pattern on the surface, the coin can be efficiently identified by using an excitation frequency of 7 K (Hz) to 10 K (Hz).
[0023]
The excitation driving means 12 having the above configuration receives the square wave signal output from the oscillation circuit means 11 and integrates the square wave by the integrating circuit including the resistor R5, the capacitor C4, and the resistor R6 to approximate a triangular wave. The exciting coil 1 is driven by the approximate triangular wave signal after being converted into a waveform. The LC resonance circuit composed of the excitation coil 1 and the capacitor C1 resonates at the frequency, and both ends of the excitation coil 1 are driven with a sine waveform as a result.
[0024]
The bridge circuit means 13 configured as described above constitutes an AC bridge circuit, and includes an impedance Z1 formed by the capacitor C2 connected in parallel with the receiving coil 2a and a capacitor C3 connected in parallel with the receiving coil 2b. If the impedance is Z2, the impedance of the resistor R1 is Z3, and the impedance of the resistor R2 is Z4, the condition for the AC bridge to be in equilibrium is:
Z1 ・ Z4 = Z2 ・ Z3
It becomes.
[0025]
Here, as shown in FIG. 3, since the output of the bridge circuit means 13 is a signal appearing between the connection point of the reception coils 2a and 2b and the connection point of the resistors R1 and R2, it is now received. Assuming that the voltage across the coil 2a is V1, the current flowing through the impedance Z1 is i1, the voltage across the receiving coil 2b is V2, and the current flowing through the impedance Z2 is i2, the voltage Vdef of the signal appearing between the two connection points is (Provided that the impedance Z3 of the resistor R1 and the impedance Z4 of the resistor R2 are equal).
[0026]
V1 = Z1 · i1
V2 = Z2 · i2
Vdef = V1-V2
Vdef = Z1, i1-Z2, i2
In this embodiment, the resonance frequency of the LC resonance circuit composed of the reception coil 2a and the capacitor C2 and the resonance frequency of the LC resonance circuit composed of the reception coil 2b and the capacitor C3 are substantially equal to the oscillation frequency output from the oscillation circuit means 11. Thus, the impedances Z1 and Z2 are substantially equal, and the voltage of the signal appearing between the two connection points is a voltage signal caused by the difference between the currents i1 and i2.
[0027]
The operation amplifying means 14 configured as described above receives the AC voltage signal output from the bridge circuit means 13, amplifies the signal to a desired AC voltage signal, and outputs it to the detection circuit means 15.
[0028]
The detection circuit means 15 configured as described above receives the AC voltage signal output from the differential amplification means 14 and performs detection rectification by the diode D1, and the bridge circuit means is constituted by an integration circuit constituted by a resistor R12 and a capacitor C8. It converts into a DC voltage signal corresponding to 13 outputs.
The AD conversion means 17 having the above configuration is realized by using, for example, a successive approximation conversion type AD converter with a resolution of 8 bits built in the MPU 20. The AD conversion means 17 inputs an analog DC voltage signal output from the detection circuit means 15, performs sampling at a predetermined interval, converts it into a digital signal corresponding to the output of the bridge circuit means 13, and converts the digital signal string into a signal. Output to the inspection means 18.
[0029]
The signal inspecting means 18 having the above configuration receives the digital signal sequence on the amplitude axis output from the AD converting means 17, temporarily stores it in a memory means such as a RAM, and stores the digital signal temporarily stored in the RAM. The statistical value of the column and the data sequence of the denomination stored in advance in the memory means 21 is obtained, and the statistical value is compared with a predetermined value stored in advance in the memory means 21 to obtain a predetermined feature. It is inspected whether or not it is provided, and the result of the inspection is output to the output terminal 19.
As a specific method for obtaining the statistical value, the following equation for obtaining the correlation coefficient can be used.
[0030]
[Expression 1]

In the above equation, N is the number of samplings, variable Xi is the value of the digital signal sequence obtained by measuring the coin to be tested with the sampling value, and variable Yi is the denomination that can be received in advance using the apparatus of the present invention. This is a statistical value obtained by sampling measurement. Xa and Ya are average values of the respective values.
If the processing speed of the MPU is taken into account, the deviation value (Yi−Ya) between the sampling value Yi of the acceptable denomination in the deviation cross product sum of the numerator and the average value Ya in the above equation 1, and the equation 1 By calculating in advance the square root of the sum of squares of the deviation between the sampling value Yi of the denominator and its average value Ya and storing the value in the memory means 21, it becomes possible to significantly increase the subsequent processing speed. .
[0031]
Here, since the absolute value of the correlation coefficient r obtained from the equation 1 is in a range of 0 ≦ | r | ≦ 1, as is well known, the correlation coefficient r is compared with a predetermined value stored in advance. It is possible to check whether or not the coin to be tested has a predetermined characteristic. When the coefficient r is infinitely close to “1”, the coin to be tested is true with respect to a coin of a denominated type. Can be determined. However, if the coefficient is close to zero as a result of inspection, the coin can be determined as false. Therefore, a value close to 1 that is 1 or less is set in accordance with the target coin to be determined for the predetermined value of true / false discrimination, and when a correlation coefficient r larger than the set value is obtained, Is recognized as a coin.
[0032]
Here, the characteristics of the representative coin measured by the apparatus of the present invention will be described with reference to FIGS. FIG. 6 is a diagram showing characteristics of representative coins. FIG. 7 is a comparison diagram showing specifications of representative coins. In FIG. 7, the US 5CENT currency of the representative coin and the 5CENTESIMOS currency of Panama are coins that are almost similar in material (brass), diameter, and thickness. If the coin is viewed visually, the only difference between the two coins is the design of the coin surface.
[0033]
FIG. 6 is a characteristic diagram showing the result of measuring the coin by exciting the exciting coil 1 at an exciting frequency of 90 K (Hz) using the apparatus according to the present invention. In FIG. 6, reference numeral 50 (indicated by a thick line) is that of a US 5CENT currency, and reference numeral 51 is that of a Panama 5CENTESIMOS currency. From the figure, it can be seen that the difference in characteristics between the two coins appears in the first peak and the last peak. This is because the eddy current generated on the coin surface generates a demagnetizing field characterized by the unevenness of the pattern on the coin surface, thereby detecting a slight difference in electromotive force generated in each of the two receiving coils. There is nothing else. In the prior art, such a difference could not be detected. Next, the operation of the apparatus 30 for inspecting the authenticity of the coin will be described in detail with reference to FIGS.
[0034]
In FIG. 4, a device 30 for checking the authenticity of a coin drops the coin 3 inserted from the coin insertion slot 31 onto the coin rail 4 provided below the coin insertion slot 31 by natural fall. The coin 3 that has fallen onto the coin rail 4 falls while rolling downstream in the direction away from the coin insertion slot 31 through the coin passage 6 (FIG. 1B). The coin 3 passes through the outer diameter detection coil 32, the material detection coil 33, the excitation coil 1 of the concave / convex pattern detection coil, and the reception coils 2a and 2b while moving in the coin passage 6. The device 30 checks the authenticity of the coin 3 while the coin 3 passes through the detection coils. When it is determined that the coin 3 is authentic as a result of the inspection, the sorting solenoid 35 is driven based on the signal output to the output terminal 19 to operate the gade 34, and the coin 3 is guided to a genuine coin passage (not shown). . However, when the coin 3 is determined to be a false coin as a result of the inspection, the coin 3 is guided to a false coin passage (not shown) without operating the gate 34 and discharged from a discharge port (not shown).
[0035]
Here, assuming that the coin 3 is a genuine coin, the coin 3 guided to the genuine coin passage continues to fall freely and eventually falls to the coin rail 36. The coins 3 that have fallen onto the coin rail 36 are sorted for each denomination by a well-known sorting means (not shown) and discharged from the corresponding discharge ports A, B, C, and D provided for each denomination.
A well-known technique can be used for the inspection means of the outer diameter detection coil 32 and the material detection coil 33.
[0036]
Here, the operation of the apparatus 30 for inspecting the authenticity of the coin by the detection coil for detecting the uneven pattern will be described in detail with reference to the flowchart of FIG. In FIG. 8, when the apparatus is turned on, in step 100, initial setting such as input / output in the MPU 20 is performed. After executing step 100, the process of determining whether or not a coin has been inserted into the apparatus using the signal of the detection coil in the determination process of step 101 is executed. If it is determined in step 101 that a coin has been inserted, the program proceeds to AD conversion processing in step 102. However, if it is determined in step 101 that no coin has been inserted, the standby process is looped so as to wait for the arrival of a coin.
[0037]
If it is determined in step 101 that a coin has been inserted, the process proceeds to AD conversion processing in step 102. In the AD conversion process of step 102, when a coin arrives in the detection coil, the signal is received and sampling of the output signal of the detection circuit means 15 which is a signal from the reception coils 2a and 2b of the detection coil for detecting the uneven pattern is started. To do. The sampling result is temporarily stored in a memory means such as a RAM in the MPU 20, and the operation proceeds to step 103.
[0038]
In step 103, the digital signal sequence value temporarily stored in the memory means and the statistical value of acceptable coins stored in advance in the memory means 21 are used to calculate the correlation coefficient r. The process proceeds to step 105 for authenticity determination.
In step 105, the authenticity determination is performed by comparing the correlation coefficient obtained by the calculation process in step 103 with a predetermined value of a receivable coin stored in advance, and if the correlation coefficient r> predetermined value, It determines with it being a true thing, and progresses to the true coin process of step 106. However, when it is determined that the correlation coefficient r <predetermined value, the test coin is determined to be false, the false coin process of step 104 is executed, and the process returns to the standby loop.
[0039]
Here, it is assumed that the true coin process of step 106 is executed on the assumption that the test coin is determined to be true in the authenticity determination process of step 105. The true coin process of step 106 executes a process of outputting a true coin signal, a denomination signal and the like based on the determination result, and returns to the standby loop.
FIG. 9 is a diagram showing a configuration of a detection coil for detecting the uneven pattern according to the second embodiment of the present invention. The difference from the first embodiment described above is that the line 5b connecting the centers of the magnetic pole faces of the long core of the U-shaped core of the exciting coil 1 connects the centers of the receiving

coils

2a and 2b. The line 5b is only the point where the exciting coil 1 and the receiving

coils

2a and 2b are disposed so as to pass through the intermediate point between the receiving

coils

2a and 2b. Since the operation and effect are the same as those of the first embodiment, the description thereof is omitted.
[0040]
FIG. 10 is a diagram showing a configuration of a detection coil for detecting the uneven pattern according to the third embodiment of the present invention. The difference from the first embodiment described above is that the line 5a connecting the centers of the receiving

coils

2a and 2b is shifted in the vertical direction with respect to the coin rail 4 on which the coin 3 rolls and falls, and the target coin 3 The only difference is that it passes through the center position. In the case of the third embodiment, since the receiving

coils

2a and 2b are arranged at the center of the target coin 3, the detection value differs depending on the uneven pattern at the center of the coin 3, and the center of the coin It is suitable for identifying the authenticity of coins with or without holes.
[0041]
FIG. 11 is a diagram showing a configuration of a detection coil for detecting a concavo-convex pattern according to the fourth embodiment of the present invention. The difference from the first embodiment described above is that the arrangement of the receiving coils is rotated by 90 degrees, and the line 5a connecting the centers of the receiving

coils

2a and 2b is connected to the line 5b connecting the center of the magnetic pole surface of the core of the exciting coil 1. This is a point configured to be orthogonal and intersect at the center of the exciting coil 1. Also in the fourth embodiment, since the receiving

coils

2a and 2b are arranged at positions corresponding to the central part of the target coin, it is true or false for a coin having a concavo-convex pattern change in the central part of the coin, or a coin not having it. The fourth embodiment is suitable for the determination.
[0042]
As described above, the arrangement positions of the reception coils 2a and 2b (the arrangement positions of the excitation coils corresponding to the arrangement positions of the reception coils) are the uneven patterns on the surface of the target coin to be determined authenticity. Depending on the difference (if there is a difference in the concavo-convex pattern due to the presence or absence of a hole in the center, or if there is a difference in the concavo-convex pattern on the periphery of the coin), it may be changed.
In addition, the present invention forms an electromagnetic field by exciting the exciting coil 1 at a frequency such that the electromagnetic field penetrates only the surface of the coin and does not penetrate to the center, and the demagnetizing field due to the eddy current generated near the coin surface is generated. Since the influence is measured, it is desirable that the surfaces of the receiving

coils

2a and 2b facing the coin are closer to the coin surface.
[0043]
Therefore, as shown in FIG. 12, the receiving

coils

2a and 2b are arranged along the position where the receiving

coils

2a and 2b of the passage wall 7a are disposed, that is, along the line 5a connecting the centers of the receiving

coils

2a and 2b in FIG. The receiving

coil

2a, 2b may be formed in a substantially close proximity to the coin surface by forming the position where is disposed with a material 200 having a high magnetic permeability.
In each of the embodiments described above, the exciting coil 1 is shown using a U-shaped core. However, other shapes such as a U-shape may be used as appropriate without departing from the spirit of the present invention.
[0044]
【The invention's effect】
According to the present invention, since the concave / convex pattern on the coin surface can be detected, a small and high-performance coin inspection apparatus can be provided at low cost for various coins.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing a configuration of a detection coil for detecting a concavo-convex pattern according to a first embodiment of the present invention, wherein FIG. 1A is a front view, and FIG.
FIG. 2 is a schematic block diagram of a circuit in an embodiment of the present invention.
FIG. 3 is a specific diagram of a circuit in the same embodiment;
FIG. 4 is a front view showing an apparatus for inspecting the authenticity of a coin in an embodiment of the present invention.
FIGS. 5A and 5B are a front view and a cross-sectional view, respectively, illustrating the configuration of the coil according to the embodiment of the present invention in detail.
FIG. 6 is a characteristic diagram showing characteristics of a representative coin in the embodiment of the present invention.
FIG. 7 is a comparison diagram showing specifications of a representative coin in the embodiment of the present invention.
FIG. 8 is a flowchart of the operation in the embodiment of the present invention.
FIGS. 9A and 9B are diagrams showing a configuration of a detection coil for detecting a concavo-convex pattern according to a second embodiment of the present invention, wherein FIG. 9A is a front view, and FIG. 9B is a cross-sectional view.
FIGS. 10A and 10B are diagrams showing a configuration of a detection coil for detecting a concavo-convex pattern according to a third embodiment of the present invention, wherein FIG. 10A is a front view, and FIG. 10B is a cross-sectional view.
FIGS. 11A and 11B are diagrams illustrating a configuration of a detection coil for detecting a concavo-convex pattern according to a fourth embodiment of the present invention, where FIG. 11A is a front view and FIG. 11B is a cross-sectional view.
FIG. 12 is an explanatory diagram showing an example in which a portion of a coin passage wall on which a receiving coil is arranged is made of a material having high magnetic permeability in each embodiment of the present invention.
[Explanation of symbols]
1 Excitation coil
2a, 2b Receiver coil
3 coins
4 Coin rail
6 Coin passage
7a, 7b Coin passage wall

Claims

In the vicinity of the passage wall on one side of the coin passage, the exciting coil and the receiving coil are electromagnetically coupled, and the influence of the demagnetizing field due to the eddy current generated on the surface of the coin when the coin passes through the electromagnetic field The excitation coil is excited at a frequency that can be detected by the receiving coil, and a difference in the concave / convex pattern of the coin is detected by an electromotive force signal detected by the receiving coil to inspect the authenticity of the coin for identifying the coin. Method.

An oscillation circuit means for oscillating a set frequency, an excitation drive means connected to the output of the oscillation circuit means, and a passage on one side of the coin passage so that two magnetic poles are directed to a coin passage inclined at a predetermined angle. An excitation coil disposed in the vicinity of the wall and connected to the excitation drive means; two receiving coils having substantially the same characteristics disposed in the vicinity of the passage wall so as to be electromagnetically coupled to the excitation coil; and the excitation coil And the receiving coil constitutes an electromagnetic field, the bridge circuit means configured to include the receiving coil, the differential amplifying means connected to the bridge circuit means, and the detecting means connected to the differential amplifying means, , Connected to the output of the detecting means, and a signal obtained when the coin to be tested acts in the electromagnetic field, and whether or not the coin to be tested has a predetermined characteristic based on the signal. Inspection means for checking and outputting a result of the inspection, wherein the inspection means compares the signal with a characteristic of a predetermined denomination stored in advance, and the signal is within a predetermined allowable range for the characteristic. A method for inspecting the authenticity of a coin, characterized in that a signal indicating that the subject coin is true is output.

3. The method for inspecting authenticity of a coin according to claim 2, wherein the two receiving coils are differentially connected.

The two receiving coils are arranged at a predetermined interval above the coin rail arranged in the coin path and so that a line connecting the centers of the two receiving coils is substantially parallel to the coin rail, 4. The apparatus according to claim 2, wherein a line connecting the center of the two magnetic poles at a predetermined interval from the receiving coil and above or below the receiving coil is arranged so as to be substantially parallel to the coin rail. A method for inspecting the authenticity of the described coin.

5. The coin passage wall is formed so that the coin that rolls and falls is inclined toward the passage wall side of one side portion of the coin passage in which the exciting coil and the receiving coil are disposed. A method for inspecting the authenticity of the described coin.

6. The method for inspecting the authenticity of a coin according to claim 1, wherein a frequency for exciting the exciting coil is selected and set according to a material of a coin to be identified.

7. The exciting coil according to claim 1, wherein the exciting coil comprises a U-shaped or U-shaped magnetic material having two magnetic poles on the same surface and a coil wound around the magnetic material. To inspect the authenticity of coins.

8. The method according to claim 1, wherein the electromotive force signal detected by the receiving coil is detected by sampling every predetermined period, and statistical processing is performed based on the sampling value to detect the characteristic of the detected coin, thereby identifying the coin. A method for inspecting the authenticity of the coin described in the item.

9. The method for inspecting the authenticity of a coin according to claim 8, wherein the statistical processing is processing for obtaining a correlation coefficient with a reference coin, and the coin is identified by the magnitude of the correlation coefficient.

In the vicinity of the passage wall on one side of the coin passage, the exciting coil and the receiving coil are electromagnetically coupled, and the influence of the demagnetizing field due to the eddy current generated on the surface of the coin when the coin passes through the electromagnetic field And a means for detecting a difference in the uneven pattern of the coin by an electromotive force signal detected by the receiving coil by exciting the exciting coil at a frequency at which the receiving coil can detect the coin. A device that inspects the authenticity of a coin that identifies the coin.

An oscillation circuit means for oscillating a set frequency, an excitation drive means connected to the output of the oscillation circuit means, and a passage on one side of the coin passage so that two magnetic poles are directed to a coin passage inclined at a predetermined angle. An excitation coil disposed in the vicinity of the wall and connected to the excitation drive means; two receiving coils having substantially the same characteristics disposed in the vicinity of the passage wall so as to be electromagnetically coupled to the excitation coil; and the excitation coil And a receiving circuit comprising an electromagnetic field, a bridge circuit means configured to include the receiving coil, a differential amplifying means connected to the bridge circuit means, and a detecting circuit means connected to the differential amplifying means Connected to the output of the detection circuit means, and based on a signal obtained when the coin to be tested acts in the electromagnetic field, the characteristics of the coin to be tested are inspected and stored in advance as a result of the inspection. And a test means for outputting a signal indicating that the coin to be tested is true when the signal is within a predetermined allowable range with respect to the feature. A device that inspects the authenticity of a characteristic coin.

12. The apparatus for inspecting authenticity of a coin according to claim 11, wherein the two receiving coils are differentially connected.

The two receiving coils are arranged at a predetermined interval above the coin rail arranged in the coin path and so that a line connecting the centers of the two receiving coils is substantially parallel to the coin rail, 13. The apparatus according to claim 11 or 12, wherein a line connecting the centers of the two magnetic poles at a predetermined interval from the receiving coil and above or below the receiving coil is arranged substantially parallel to the coin rail. A device for inspecting the authenticity of the described coin.

14. The coin passage wall is formed so that a coin that rolls and falls is inclined toward a passage wall side of one side portion of the coin passage in which the exciting coil and the receiving coil are disposed. A device for inspecting the authenticity of the described coin.

15. The apparatus for inspecting the authenticity of a coin according to claim 10, wherein a frequency for exciting the exciting coil is selected and set according to a material of a coin to be identified.

16. The exciting coil according to claim 11, wherein the exciting coil comprises a U-shaped or U-shaped magnetic material having two magnetic poles on the same surface and a coil wound around the magnetic material. A device to inspect the authenticity of coins.

11. A means for sampling an electromotive force signal detected by the receiving coil every predetermined period, and a statistical processing means for performing statistical processing based on the sampling value to detect a characteristic of a detected coin and identifying a coin. An apparatus for inspecting the authenticity of coins according to one of 16 items.

18. The authenticity of a coin according to claim 17, wherein the statistical processing of the statistical processing means is a process of obtaining a correlation coefficient with a reference coin, and the statistical processing means identifies a coin based on a magnitude of the correlation coefficient. Inspecting equipment.