JP2004213582A - Rfid tag, reader/writer and rfid system with tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tag capable of responding to a plurality of standards, a reader/writer communicating with the tag and an RFID (Radio Frequency IDentification) system with the tag. <P>SOLUTION: This RFID system is formed by disposing a plurality of antennas in a single tag 2 and connecting an IC operating by different standards to the respective antennas. The plurality of antennas may be so formed that a small antenna is disposed inside a large spiral antenna, two spiral antennas are provided in parallel, two spiral antennas are opposed to each other via a seal containing a soft magnetic material and a conductive material, a spiral antenna is assembled with an antenna formed by winding a conductor around a flat magnetic core or two flat cores are provided and antennas with conductors wound therearound are provided in parallel or stacked on the other. These constitutions can suppress mutual interference between the two antennas and use them in different forms of a proximity type and a neighborhood type. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３０】
表１より、第１アンテナコイル８ａと第２アンテナコイル８ｂの寸法を同じにした場合（共に長さ７５ｍｍ、幅４５ｍｍ）、双方のアンテナが干渉して共に作動距離が極端に短くなっている。これに対して、第２アンテナコイル８ｂの寸法を小さくし、第１アンテナコイル８ａの内側に配置した場合は、単独で動作させた場合に比べて作動距離は小さいが、第１通信部６ａ（ＩＳＯ１５６９３）に関しては５５〜７０ｍｍ、第２通信部６ｂ（ＩＳＯ１４４４３）に関しては４〜８ｍｍの作動距離を確保することができ、１つのタグ２の中に複数のアンテナを共存させることが可能であることがわかる。
【００３１】
このように上記構造では、２つの共振回路の干渉は許容できる程度に止めることはできるが、ＩＳＯ１５６９３の作動距離を大きくするとＩＳＯ１４４４３の作動距離は短くなり、それぞれの最適条件でも作動距離は単独の場合に較べ短いという欠点はあるが、構造が簡単で製造が容易であり、２つのアンテナの領域を重ねることができるためタグ２を小さくできるという特徴がある。また、作動距離がもっとも長くなる方向が現在広く使用されている空芯コイルのタグと同じであるため、ＩＤカード等として使用する場合、使用者の習熟が容易である。
【００３２】
［実施例２］
次に、本発明の第２の実施例に係るＲＦＩＤタグについて、図３を参照して説明する。図３は、第２の実施例に係るタグのアンテナコイルの構造を示す図である。
【００３３】
第１の実施例では、第１アンテナコイル８ａの内側に第２アンテナコイル８ｂを設置したが、アンテナの相互干渉を抑制するため巻線は重ならない方が好ましい。そこで本実施例では、図３に示すように、ベース板７上に第１アンテナコイル８ａと第１ＩＣ９ａとを含む第１通信部６ａと、第２アンテナコイル８ｂと第２ＩＣ９ｂとを含む第２通信部６ｂとを所定の間隔（Ｗ）だけ離して並べて設置している。
【００３４】
なお、図では２つのアンテナコイルを略等しいサイズで対称となるように形成しているが、各々のアンテナコイルの構造は図の構成に限定されず、ベース板７上に各々の巻き線が交差しないように形成されていればよく、第１の実施例と同様に、そのサイズ、形状、巻き数、線幅、配置位置、製法等はＲＦＩＤシステムに要求される性能、規格等を勘案して適宜設定することができる。
【００３５】
上記構造のタグの性能を確認するために、長さ７５ｍｍ×幅４５ｍｍ、巻数２回の第１のアンテナコイル８ａと、長さ４５ｍｍ×幅２７ｍｍ、巻数４回の第２のアンテナコイル８ｂの巻き線が最も近づく部分の間隔（Ｗ）を変化させた場合の単独での作動距離と同時に動作させた場合の作動距離とを測定した。その結果を表２に示す。
【００３６】
【表２】

【００３７】
表２より、第１アンテナコイル８ａと第２アンテナコイル８ｂの間隔が０ｍｍの場合は双方のアンテナが干渉して共に作動距離が極端に短くなっているが、間隔が増加するに従って作動距離が大きくなっていることがわかる。特に、間隔４０ｍｍでは単独で動作させる場合とほぼ同様の作動距離が得られており、第１の実施例よりもアンテナの相互干渉が抑制されていることが分かる。
【００３８】
この構造では、アンテナコイルを所定の間隔をあけて並べるためにアンテナの占有面積が大きくなり、タグ２の大きさが決まっている場合はアンテナコイルを小さくしなければならず、作動距離は多少小さくなるが、サイズの制限が厳しくない場合は良好な作動距離を得ることができ、また、既存のアンテナコイルの形状や構造を変更せずに使用できるため、タグ２のコストを低減できるという特徴がある。
【００３９】
［実施例３］
次に、本発明の第３の実施例に係るＲＦＩＤタグについて、図４乃至図７を参照して説明する。図４は、第３の実施例に係るタグのアンテナコイルの構造を示す図であり、図５は、本実施例の効果を説明するための図である。また、図６は、本実施例のタグに用いるシールの他の構造を示す図であり、図７は、本実施例で使用する軟磁性材の構造を模式的に示す図である。なお、本実施例は２つのアンテナコイルの干渉を抑制するために軟磁性材と導電材とを備えるシールを設けたことを特徴とするものである。
【００４０】
図４に示すように、本実施例のタグ２は、２枚のベース板７ａ、７ｂの各々に、第１アンテナコイル８ａと第１ＩＣ９ａとを含む第１通信部６ａと、第２アンテナコイル８ｂと第２ＩＣ９ｂとを含む第２通信部６ｂ（図示せず）とを設け、導電材１２を軟磁性材１１ａ及び１１ｂで挟み込んで形成したシール１０を介して２枚のベース板７ａ、７ｂを対向配置したものである。なお、本実施例においても各々のアンテナコイルの構造は図の構成に限定されず、そのサイズ、形状、巻き数、線幅、配置位置、製法等は任意に設定することができる。
【００４１】
ここで、シール１０を介在させることなく２枚のベース板７ａ、７ｂを対向するように配置した場合、図５（ｂ）に示すように第１アンテナコイル８ａの磁束１３ａと第２アンテナコイル８ｂの磁束１３ｂとが鎖交し干渉を起こしてしまうが、軟磁性材１１ａ／導電材１２／軟磁性材１１ｂからなるシール１０を介在させることにより、図５（ａ）に示すように、各々のアンテナコイルの磁束１３は軟磁性材１１ａまたは１１ｂ中を通り、その端面から略平行に抜けていくため、両アンテナコイルの磁束の鎖交を防止することができ、アンテナの相互干渉を抑制することができる。
【００４２】
ここでシール１０を介在させる構造の場合、アンテナコイルを重ね合わせることができるため、第２の実施例に比べてアンテナコイルの寸法を大きくすることができるが、一方、導電材１２がリーダ／ライタ３からの電波を遮蔽するために作動距離はやや小さくなる。その場合には、例えば、図６に示すように導電材１２の中央部（アンテナコイルの略中央部）に孔１４を設ける構造としたり、導電材１２の厚さを薄くする等の方法によりリーダ／ライタ３からの電波の遮蔽を緩和すれば作動距離を改善することができる。なお、軟磁性材１１ａ、１１ｂの中央部に孔を設けても作動距離は変わらない。このため軟磁性材１１ａ、１１ｂの節約のため中央部に孔を形成してもよく、また軟磁性材１１ａ、１１ｂと導電材１２とを積層した後、積層した材料を打ち抜き等の方法を用いて孔１４を設けても良い。
【００４３】
この導電材１２は３００μｍを超えると電波は全く通過しないため、導電材１２を回り込んだリーダ／ライタ３の電波のみがアンテナコイルに達することになるため作動距離は小さくなる。また、導電材１２がスパッタリング等により形成された極めて薄い膜（例えば０．１μｍ程度の膜）の場合はその抵抗の損失によりアンテナコイルの損失が増加する。上記の遮蔽効果と抵抗の損失及び材料の入手の容易さ等を勘案すると、導電材１２としては５μｍ〜３００μｍ、好ましくはアルミ箔として広範囲に使用されている８μｍ〜２０μｍ程度の厚さが適当である。
【００４４】
また、軟磁性材は、アモルファス合金、パーマロイ、電磁鋼、珪素鉄、センダスト合金、Ｆｅ−Ａｌ合金又は軟磁性フェライトの急冷凝固材、鋳造材、圧延材、鍛造材又は焼結材や、アモルファス箔又はアモルファス箔の積層材や、金属粉、カーボニル鉄粉、還元鉄粉、アトマイズ粉（純鉄、Ｓｉ、Ｃｒ、Ａｌ等を含む鉄、パーマロイ、Ｃｏ−Ｆｅ等）、アモルファス粉（Ｂ、Ｐ、Ｓｉ、Ｃｒ等を含む鉄、Ｃｏ、Ｎｉを水アトマイズして製造したもの）等の粒状の粉体若しくはフレークとプラスチック、ゴム等の有機物との複合材、又は上記粉体若しくはフレークを含む塗料の塗膜であっても良い。
【００４５】
上記複合材を製造する方法としては、射出成形、塗布、圧縮成形、圧延等を用いることができる。射出成形又は圧縮成形により形成された軟磁性材はフェライトにより形成されたものと比較して、強靭であるため薄くしても割れ難いという特徴がある。塗布の場合は、例えば、粒状粉体をアトラター、ボールミル、スタンプミル等で扁平化してフレークとした後、フレーク又は粒状粉体を含む塗料をフィルム上に塗布／乾燥を繰り返して形成することができ、その際、塗布中に磁場を印加することによりフレークを一定の方向に配向させることができ、特性を向上させることができる。
【００４６】
また、複合材におけるプラスチックとしては加工性の良い熱可塑性のプラスチックを用いたり、或いは耐熱性の良い熱硬化性のプラスチックを用いたりすることができ、また、絶縁性を有するアクリル、ポリエステル、ポリ塩化ビニル、ポリエチレン、ポリスチレン、エポキシ等の樹脂を用いることもできる。
【００４７】
上記各種材料、製法は、タグ２に求められる性能に応じて、適宜選択することができる。例えば、複合材の場合は、図７（ａ）に示すような構造となり、プラスチック、ゴム等の樹脂バインダー１６中に粉体、フレーク１５が分散され、その粉体若しくはフレーク１５が相互に絶縁されているため、軟磁性材全体としては導電性を有せず、高周波の電波を受けても渦電流損失を減少させることができ、本発明の構造に用いる材料として望ましい。また、アモルファス箔の積層材の場合は、図７（ｂ）に示すようにアモルファス箔１７と絶縁層１８とが交互に積層された構造となり、製造が容易であるがアモルファス箔１７での損失が大きいという問題がある。
【００４８】
上記構造のタグの性能を確認するために、導電材１２の厚さを変化させた場合及び孔１４を設けた場合の単独での作動距離と同時に動作させた場合の作動距離とを測定した。また、シール１０の効果を確認するためにシール１０無しのタグについても同様に測定した。その結果を表３に示す。なお、本実験では軟磁性材としてはフレークを含む複合材を使用し、圧延で厚さ０．５ｍｍに加工したものを用い、導電材１２にはアルミを用い、試料（Ａ）及び（Ｂ）は厚さ０．１ｍｍ、試料（Ｃ）は厚さ０．０１３ｍｍとした。また、試料（Ｂ）及び（Ｃ）に設ける孔１４の寸法は５５ｍｍ×２５ｍｍとした。
【００４９】
【表３】

【００５０】
表３より、シール１０無しの試料では双方のアンテナとも作動距離は極端に短くなっているが、シール１０を介在させることにより作動距離が大幅に向上していることが分かる。また、導電材１２を全面に設けた試料（Ａ）に比べて、試料（Ａ）の導電材１２の略中心部に５５ｍｍ×２５ｍｍの孔１４を設けた試料（Ｂ）では動作距離が大きくなっており、更に、試料（Ｂ）の導電材１２の厚さを薄くした試料（Ｃ）では更に作動距離が大きくなっていることが分かる。
【００５１】
以上より、本実施例の構造では、タグ２が小さくても作動距離を比較的大きくすることができ、特に導電材１２に孔１４を設ければ作動距離は更に大きくすることができる。
【００５２】
［実施例４］
次に、本発明の第４の実施例に係るＲＦＩＤタグについて、図８を参照して説明する。図８は、第４の実施例に係るタグのアンテナコイルの構造を示す図である。
【００５３】
図８に示すように、本実施例のタグ２は、２枚のベース板７ａ、７ｂの各々に、第１アンテナコイル８ａと第１ＩＣ９ａとを含む第１通信部６ａと、第２アンテナコイル８ｂと第２ＩＣ９ｂとを含む第２通信部６ｂとを設け、各々のアンテナコイルをずらして配置し、かつ、アンテナコイルが重なる領域にのみ平板状の軟磁性材１１を配置したものである。なお、本実施例においても各々のアンテナコイルの構造は図の構成に限定されず、そのサイズ、形状、巻き数、線幅、配置位置、製法等は任意に設定することができる。また、第３の実施例と同等に、アンテナコイルが重なる領域に導電材１２を軟磁性材１１ａ及び１１ｂで挟み込んで形成したシール１０を配置する構成としてもよい。
【００５４】
上記構成では、磁束が鎖交する部分にのみ軟磁性材１１を設けているため、リーダ／ライタ３からの電波の遮蔽を抑制することができる。上記構造のタグの性能を確認するために、第１ベース板７ａに長さ４５ｍｍ×幅４５ｍｍ、巻数４回の第１アンテナコイル７ａを形成してＩＳＯ１５６９３に準拠した第１ＩＣ９ａを接続し、第２ベース板７ｂに長さ４５ｍｍ×幅４５ｍｍ、巻数３回の第２アンテナコイル７ｂを形成してＩＳＯ１４４４３に準拠した第２ＩＣ９ｂを接続し、各々のアンテナコイルをずらして対向させ、その間に１５ｍｍ×５０ｍｍの軟磁性材１１を配置した試料を作成し、その作動距離を測定した。その結果を表４に示す。なお、軟磁性材１１としてはＦｅ−Ｃｒ−Ｓｉ系のフレークとプラスチックからなる複合材を使用し、５０μｍのＰＥＴに厚さ１００μｍの複合材を塗布した塗布材を用いた。
【００５５】
【表４】

【００５６】
表４より、第１通信部６ａの作動距離は２５０ｍｍ、第２通信部６ｂの作動距離は２３ｍｍであり、アンテナコイルの全面にシール１０を配置した第３の実施例に比べて、作動距離が更に改善されていることが分かる。
【００５７】
以上より、本実施例の構造では、第１乃至第３の実施例よりも作動距離を長くすることができ、タグ２をそれぞれの単独で動作させた場合と同等、即ちそれぞれのＩＣが空芯の渦巻き状アンテナに接続されたタグと同じ作動距離を持つことから最適の方法であると言える。また、作動距離がもっとも長くなる方向が現在広く使用されている空芯コイルのタグと同じであるため、ＩＤカード等として使用する場合、使用者の習熟が容易であるという特徴もあり、また、２つのＩＣの作動距離が最大となる方向が同じであるため、どちらのＩＣを作動させるかを意識すること無く使用することができる。
【００５８】
［実施例５］
次に、本発明の第５の実施例に係るＲＦＩＤタグについて、図９を参照して説明する。図９は、第５の実施例に係るタグのアンテナコイルの構造を示す図である。なお、本実施例はベース板に渦巻き状に形成したアンテナコイルと磁芯に導線を巻回して形成したアンテナコイルとを混在させたことを特徴とするものである。
【００５９】
図９に示すように、本実施例のタグ２は、ベース板７上に、渦巻き状の第１アンテナコイル８ａと第１ＩＣ９ａとを含む第１通信部６ａを設け、第１アンテナコイル８ａの内側に、平板状の軟磁性材料からなる磁芯１９に第２アンテナコイル８ｂを巻回し第２ＩＣ９ｂを接続した第２通信部６ｂを配置したものである。なお、本実施例においても各々のアンテナコイルの構造は図の構成に限定されず、そのサイズ、形状、巻き数、線幅、配置位置、製法等は任意に設定することができる。
【００６０】
上記構造のタグの性能を確認するために、長さ７５ｍｍ×幅４５ｍｍ、巻数２回の渦巻き状の第１アンテナコイル８ａにＩＳＯ１５６９３に準拠した第１ＩＣ９ａを接続し、第１アンテナコイル８ａの内側の略中央部に、幅４０ｍｍ×長さ２５ｍｍ、厚さ０．５ｍｍの複合材からなる磁芯１９に箔線を５回巻いて第２アンテナコイル８ｂを形成し、ＩＳＯ１４４４３に準拠した第２ＩＣ９ｂを接続した試料を作成し、その作動距離を測定した。その結果、第１通信部６ａ（ＩＳＯ１５６９３）の作動距離は２１０ｍｍであり、第２通信部６ｂ（ＩＳＯ１４４４３）の作動距離は２０ｍｍであり、第４の実施例に近い作動距離が得られることが分かった。
【００６１】
以上より、本実施例のように渦巻き状のアンテナと磁芯に導線を巻回したアンテナとを混在させる構造でもアンテナの相互干渉を抑制して各々の通信部の作動距離を大きくすることができる。また、このような構成では作動距離が最大となる方向が各々の通信部で略直交する方向となるため、所望のＩＣを作動させる方向を意識的に選定することができるという特徴がある。
【００６２】
［実施例６］
次に、本発明の第６の実施例に係るＲＦＩＤタグについて、図１０を参照して説明する。図１０は、第６の実施例に係るタグのアンテナコイルの構造を示す図である。なお、本実施例は平板状の磁芯に互いに直交する方向に導線を巻回してアンテナコイルを形成することを特徴とするものである。
【００６３】
図１０に示すように、本実施例のタグ２は、平板状の軟磁性材料からなる磁芯１９に、一の方向（図では手前から奥側に向かう方向）に第１アンテナコイル８ａを巻回して第１ＩＣ９ａを接続した第１通信部６ａと、直交する方向（図では左右方向）に第２アンテナコイル８ｂを巻回して第２ＩＣ９ｂを接続した第２通信部６ｂとを形成したものである。なお、本実施例においても各々のアンテナコイルの構造は図の構成に限定されず、そのサイズ、形状、巻き数、線幅、配置位置、製法等は任意に設定することができる。
【００６４】
上記構造のタグ２の性能を確認するために、幅４０ｍｍ×長さ４０ｍｍ、厚さ０．５ｍｍのフレークを含む複合材からなる磁芯１９に厚さ３５μｍ、幅１ｍｍの箔線を１０回巻いて第１アンテナコイル８ａを形成してＩＳＯ１５６９３に準拠した第１ＩＣ９ａを接続し、第１アンテナコイル８ａと直交する方向に、厚さ３５μｍ、幅１ｍｍの箔線を５回巻いて第２アンテナコイル８ｂを形成してＩＳＯ１４４４３に準拠した第２ＩＣ９ｂを接続した試料を作成し、その作動距離を測定した。その結果、第１通信部６ａ（ＩＳＯ１５６９３）の作動距離は１１５ｍｍであり、第２通信部６ｂ（ＩＳＯ１４４４３）の作動距離は１５ｍｍであった。
【００６５】
以上より、１つの磁芯に対して異なる方向に導線を巻回する本実施例の構造でもアンテナの相互干渉を抑制して各々の通信部の作動距離を大きくすることができると共に、作動距離が最大となる方向が直交するため、所望のＩＣを作動させる方向を意識的に選定することができる。例えば、作動距離が最も長い方向はタグ２の面に平行であるため、側面に矩形の空芯アンテナを配置したゲートを通過する場合、胸のポケットに第１通信部６ａのアンテナ軸を水平になる様に入れてゲートを通過すれば、作動距離が最も長い状態となるためポケットから取り出すことなくタグ２を検知することが可能である。
【００６６】
［実施例７］
次に、本発明の第７の実施例に係るＲＦＩＤタグについて、図１１乃至図１４を参照して説明する。図１１乃至図１４は、第７の実施例に係るタグのアンテナコイルの構造を示す図である。なお、本実施例は２つの平板状の磁芯の各々に導線を巻回してアンテナコイルを形成することを特徴とするものである。
【００６７】
図１１に示すように、本実施例のタグ２は、平板状の軟磁性材からなる第１磁芯１９ａに、第１アンテナコイル８ａを巻回し第１ＩＣ９ａを接続した第１通信部６ａと、同じく平板状の軟磁性材からなる第２磁芯１９ｂに第２アンテナコイル８ｂを巻回し第２ＩＣ９ｂを接続した第２通信部６ｂとを並べて配置したものである。なお、本実施例においても各々のアンテナコイルの構造は図の構成に限定されず、そのサイズ、形状、巻き数、線幅、配置位置、製法等は任意に設定することができる。
【００６８】
上記構造のタグの性能を確認するために、幅２０ｍｍ×長さ７０ｍｍ、厚さ０．５ｍｍのフレークを含む複合材からなる磁芯を２つ設け、その一方に厚さ３５μｍ、幅１ｍｍの箔線を１５回巻いて第１アンテナコイル８ａを形成してＩＳＯ１５６９３に準拠した第１ＩＣ９ａを接続し、他方に同じく厚さ３５μｍ、幅１ｍｍの箔線を８回巻いて第２アンテナコイル８ｂを形成してＩＳＯ１４４４３に準拠した第２ＩＣ９ｂを接続し、各々の磁芯を同一平面状に平行に並べて配置した試料を作成し、その作動距離を測定した。その結果、第１通信部６ａ（ＩＳＯ１５６９３）の作動距離は７５ｍｍであり、第２通信部６ｂ（ＩＳＯ１４４４３）の作動距離は１０ｍｍであった。
【００６９】
また、２つの磁芯を用いる構造の別の形態として、図１２に示すように、平板状の軟磁性材からなる第１磁芯１９ａに第１アンテナコイル８ａを巻回して第１ＩＣ９ａを接続した第１通信部６ａと、同様に平板状の軟磁性材からなる第２磁芯１９ｂに第２アンテナコイル８ｂを巻回し第２ＩＣ９ｂを接続した第２通信部６ｂとを重ね合わせるように配置することができる。
【００７０】
上記構造のタグの性能を確認するために、幅４０ｍｍ×長さ７０ｍｍ、厚さ０．５ｍｍのフレークを含む複合材を２つ設け、一方に厚さ３５μｍ、幅１ｍｍの箔線を１０回巻いて第１アンテナコイル８ａを形成してＩＳＯ１５６９３準拠の第１ＩＣ９ａを接続し、他方に厚さ３５μｍ、幅１ｍｍの箔線を５回巻いて第２アンテナコイル８ｂを形成してＩＳＯ１４４４３準拠の第２ＩＣ９ｂを接続し、両者を磁芯の面が対向するように重ね合わせた試料を作成し、その作動距離を測定した。その結果、第１通信部６ａ（ＩＳＯ１５６９３）の作動距離は１２０ｍｍであり、第２通信部６ｂ（ＩＳＯ１４４４３）の作動距離は１５ｍｍであった。
【００７１】
以上より、本実施例の構造では、２つの通信部間をシール１０等で分離しなくてもある程度の作動距離を確保することができる。この場合、図１２の構造の方がアンテナコイルの面積を大きくできるために作動距離を大きくすることができるが、磁芯を２枚重ねる必要があるためカード型タグとした場合に厚みが増すという欠点がある。いずれの形態のタグとするかはＲＦＩＤシステムに求められる性能や使用形態を勘案して設定することができる。
【００７２】
なお、図１１及び図１２では２つの磁芯の各々に同じ方向に箔線を巻回した構造としたが、各々の磁芯に直交する方向に箔線を巻回することもできる。例えば、互いに直交する方向に箔線を巻回したアンテナを重ね合わせる構造（図１３参照）や、互いに直交する方向に箔線を巻回したアンテナを同一平面状に平行に並べる構造（図１４参照）とすることもできる。このような構造の場合も２つの通信部間をシール１０等で分離しなくてもある程度の作動距離を確保することができ、また、アンテナの軸を直交させることにより、第６の実施例と同様に、所望のＩＣを動作させる方向を意識的に選定することができる。
【００７３】
なお、上記各実施例では、タグ２内に、第１アンテナコイル８ａと第１ＩＣ９ａとを含む第１通信部６ａと、第２アンテナコイル８ｂと第２ＩＣ９ｂとを含む第２通信部６ｂの２種類の通信部を設ける構造としたが、通信部は２種類に限定されず複数であればよく、各々の通信部の規格も近傍型（ＩＳＯ１５６９３）や近接型（ＩＳＯ１４４４３）に限定されず、任意の規格に準拠したものであればよい。また、上記実施例ではＲＦＩＤシステムに用いられるタグ用のアンテナについて記載したが、本発明は上記実施例に限定されるものではなく、異なる規格で準拠したアンテナを複数配置することが求められる任意のシステムに適用することができる。
【００７４】
【発明の効果】
以上説明したように、本発明のＲＦＩＤタグ及び該タグとデータ交信を行うリーダ／ライタ並びに該タグを備えたＲＦＩＤシステムによれば、同一のタグを用いて、異なる形態（例えば、近傍型（ＩＳＯ１５６９３）と近接型（ＩＳＯ１４４４３）等）でリーダ／ライタと通信することができる。
【００７５】
その理由は、タグのアンテナとして、大きな渦巻き状のアンテナの内側に小さい渦巻き状のアンテナを配置する構造（図２）、各々の形態に適したアンテナを所定の間隔をあけて並べて配置する構造（図３）、各々のベース板に形成したアンテナを軟磁性材／導電材／軟磁性材からなるシールを挟んで対向させる構造（図４）、各々のベース板に形成したアンテナをずらして対向させ、その間にシールを挿入する構造（図８）、渦巻き状のアンテナの内側に、平板状の磁芯に導線を巻回したアンテナを配置する構造（図９）、平板状の磁芯に互いに直交する方向に導線を巻回する構造（図１０）、２つの平板状の磁芯に同一方向又は直交する方向に導線を巻回したアンテナを同一平面状に並べて又は重ね合わせて配置する構造（図１１乃至図１４）とし、各々のアンテナに異なる規格に準拠したＩＣを接続することにより、アンテナの相互作用を抑制し、同一タグ内に異なる形態で動作する通信部を形成することができるからである。
【００７６】
そして、このようなタグと、異なる規格の信号を処理する信号処理部を備えたリーダ／ライタとを備えたＲＦＩＤシステムを用いることにより、例えば、近傍型又は近接型のいずれの形態でも使用することが可能となる。また、同一のタグにより、通信距離やアンテナ軸方向の違いを利用して異なるリーダ／ライタとデータの通信を行うことができ、利用形態に合わせて複数のタグやリーダ／ライタを用意する必要がなくなり、ＲＦＩＤシステムの汎用性、柔軟性、拡張性を高めることができる。
【図面の簡単な説明】
【図１】本発明のＲＦＩＤシステムの構成を模式的に示す図である。
【図２】本発明の第１の実施例に係るタグの構造を示す平面図である。
【図３】本発明の第２の実施例に係るタグの構造を示す平面図である。
【図４】本発明の第３の実施例に係るタグの構造を示す図であり、（ａ）は斜視図、（ｂ）はＡ−Ａ′線における断面図である。
【図５】本発明の第３の実施例に係るタグの効果を説明するための図であり、（ａ）は本実施例のタグの磁束、（ｂ）は従来構造のタグの磁束を示す図である。
【図６】本発明の第３の実施例に係るタグに用いるシールの他の構造を示す図であり、（ａ）は斜視図、（ｂ）はＢ−Ｂ′線における断面図である。
【図７】本発明に用いる軟磁性材の構造を模式的に示す図である。
【図８】本発明の第４の実施例に係るタグの構造を示す図であり、（ａ）は斜視図、（ｂ）はＣ−Ｃ′線における断面図である。
【図９】本発明の第５の実施例に係るタグの構造を示す斜視図である。
【図１０】本発明の第６の実施例に係るタグの構造を示す斜視図である。
【図１１】本発明の第７の実施例に係るタグの構造を示す斜視図である。
【図１２】本発明の第７の実施例に係るタグの他の構造を示す斜視図である。
【図１３】本発明の第７の実施例に係るタグの他の構造を示す斜視図である。
【図１４】本発明の第７の実施例に係るタグの他の構造を示す斜視図である。
【符号の説明】
１ ＲＦＩＤシステム
２ タグ
３ リーダ／ライタ
４ リーダ／ライタ用アンテナ
５ 信号処理部
６ａ 第１通信部
６ｂ 第２通信部
７ ベース板
７ａ 第１ベース板
７ｂ 第２ベース板
８ａ 第１アンテナコイル（近傍型（ＩＳＯ１５６９３）用）
８ｂ 第２アンテナコイル（近接型（ＩＳＯ１４４４３）用）
９ａ 第１ＩＣ（近傍型（ＩＳＯ１５６９３）用）
９ｂ 第２ＩＣ（近接型（ＩＳＯ１４４４３）用）
１０ シール
１１、１１ａ、１１ｂ 軟磁性材
１２ 導電材
１３、１３ａ、１３ｂ 磁束
１４ 孔
１５ フレーク
１６ 樹脂バインダー
１７ アモルファス箔
１８ 絶縁層
１９ 磁芯
１９ａ 第１磁芯
１９ｂ 第２磁芯[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an RFID (Radio Frequency Identification) system that reads and writes data from and to an mounted IC chip in a non-contact manner, and particularly relates to an International Organization for Standard (ISO) / International Electrotechnical Communication (IEC). The present invention relates to a tag capable of complying with a plurality of standards conforming to the above-mentioned regulations, a reader or reader / writer communicating with the tag, and an RFID system provided with the tag.
[0002]
[Prior art]
In recent years, RFID systems for exchanging data between a tag having an IC chip and a reader / writer (or reader) have become widespread. Since the RFID system communicates data using antennas provided in each of the tag and the reader / writer, communication is possible even when the tag is separated from the reader / writer by several cm to several tens of cm. Due to its advantage of being resistant to static electricity and the like, it has been used in various fields such as factory production management, distribution management, and entry / exit management.
[0003]
The tag used in the RFID system includes a resonance circuit including an antenna coil and a capacitor, and an IC for storing information. The tag is adapted to the performance (eg, working distance and data communication speed) required of the RFID system. Tag and reader / writer are designed.
[0004]
Specifically, when the RFID system is classified by function, a proximity type (ISO15693) used for entry / exit / management of ID recognition and a proximity type (ISO14443) used for authentication / payment and electronic tickets can be used. In the proximity type, the communication speed is high (106 kbps), but the working distance is short (about 10 cm). On the other hand, in the proximity type, the communication speed (6.67 kbps) is lower than that in the proximity type, but the tag transmission capacity is increased To enable long-distance communication (50 cm to 70 cm), and the shape of the antenna coil of the tag, the IC to be used, the signal processing circuit of the reader / writer, etc. are designed according to each standard (for example, No. 183688).
[0005]
[Patent Document 1]
JP-A-14-183688 (page 2)
[0006]
[Problems to be solved by the invention]
As described above, in the RFID system, the working distance and the communication speed are specified in accordance with the use form, so that a tag manufactured according to the proximity type (or proximity type) standard can be used as the proximity type (or proximity type). In the case where the RFID system is used in a plurality of forms, it is necessary to prepare a plurality of sets of tags and readers / writers manufactured so as to correspond to each standard.
[0007]
Since this RFID system is capable of contactlessly exchanging data, it has been used for various purposes in recent years, and its use is expected to expand in the future. When the RFID system is applied, the user has to prepare tags for the number of uses, which is inconvenient, and the manufacturer also has to make tags and reader / writers for each use, which is efficient. is not.
[0008]
The present invention has been made in view of the above problems, and has as its main object to provide a tag capable of complying with a plurality of standards, a reader / writer for communicating with the tag, and an RFID system including the tag. To provide.
[0009]
[Means for Solving the Problems]
Since ISO15693 and ISO14443 have different communication systems, there is basically no interference. However, when a plurality of antennas, which are a plurality of resonance circuits, are arranged in one tag, the two resonance circuits are close to each other and interfere with each other to shorten the working distance. This mutual interference is a change in the resonance frequency and a significant decrease in the Q value. It is not impossible to cope with the change of the resonance frequency, such as changing the capacity of the capacitor so that the frequency becomes a predetermined frequency in the state of interference, but it is extremely difficult to implement because the coping itself changes the degree of interference. Cannot be prevented from significantly decreasing. The present invention proposes the following method for keeping mutual interference between coils within an acceptable range.
[0010]
The tag of the present invention is a tag for exchanging data with a reader or reader / writer without contact, and conforms to a plurality of antennas and different standards connected to the plurality of antennas in one tag. And a plurality of ICs.
[0011]
Further, the tag of the present invention is a tag for exchanging data with a reader or a reader / writer in a non-contact manner, in which two antennas composed of a spiral conducting wire are arranged in the same plane. An IC conforming to a different standard is connected to each of the two antennas, and one of the two antennas is arranged inside the other antenna; or , The two antennas may be arranged side by side at a predetermined interval.
[0012]
Further, the tag of the present invention is a tag for performing data communication with a reader or a reader / writer in a non-contact manner, and includes two antennas formed of a spiral-shaped conductor in one tag, and each of the antennas Are disposed so as to face each other via a three-layered separation layer in which a conductive material is sandwiched between soft magnetic materials, and an IC conforming to different standards is connected to each of the two antennas. The two antennas are arranged so as to be displaced in the direction of the antenna surface so that a part of the two antennas overlap when viewed from a direction orthogonal to the antenna surface, and the separation layer or the flat plate is provided at least in the overlapping region. The conductive material is not provided in a configuration in which a soft magnetic material in a shape of is provided, or in a substantially central portion of a region surrounded by the two antennas when viewed from a direction orthogonal to the antenna surface. Hole It can be configured to have been made.
[0013]
In the present invention, the conductive material is made of an aluminum plate or foil, or a copper plate or foil, and the thickness of the conductive material is set to approximately 5 μm to 300 μm, preferably approximately 8 μm to 20 μm. It can also be configured.
[0014]
Further, the tag of the present invention is a tag for performing data communication with a reader or a reader / writer in a non-contact manner, and includes a first antenna formed of a spiral conductive wire and a flat soft A second antenna in which a conductive wire is wound around a magnetic core made of a magnetic material, wherein each of the two antennas is connected to an IC conforming to a different standard, and the second antenna is The first antenna may be arranged such that the flat surface of the plate-shaped magnetic core is substantially parallel to the antenna surface of the first antenna.
[0015]
The tag of the present invention is a tag for performing data communication with a reader or a reader / writer in a non-contact manner. In one tag, lead wires are provided in different directions on a magnetic core made of a flat soft magnetic material. Two wound antennas are provided, and each of the two antennas is connected to an IC conforming to a different standard.
[0016]
Further, the tag of the present invention is a tag for performing data communication with a reader or a reader / writer in a non-contact manner, and in one tag, a conductive wire is connected to each of two magnetic cores made of a flat soft magnetic material. , And an IC conforming to different standards is connected to each of the two antennas, and the two antennas have their antenna axes substantially parallel or substantially orthogonal. Preferably, the conductive wire is wound so as to perform the above operation.
[0017]
In the present invention, the soft magnetic material is preferably a composite material of soft magnetic flakes or soft magnetic powder and plastic or rubber, and the IC includes an IC conforming to ISO15693 and an IC conforming to ISO14443. Is preferred.
[0018]
A reader or reader / writer of the present invention is a reader or reader / writer that communicates with the tag described above, and includes a plurality of signal processing units that enable data communication with each of the ICs conforming to the different standards. It is provided with.
[0019]
Further, an RFID system according to the present invention is an RFID system including the tag described above and a reader or reader / writer, wherein a plurality of antennas formed in one tag and a plurality of ICs conforming to different standards are provided. Are used to perform data communication in a plurality of forms having different working distances or different data communication speeds.
[0020]
As described above, according to the present invention, one tag includes a plurality of pairs of antennas and ICs designed to correspond to a plurality of standards (for example, standards conforming to the standards of ISO15693 and ISO14443), Since each antenna is arranged so that mutual interference can be suppressed, one tag can be used in a plurality of forms.
[0021]
Further, by providing the reader / writer with a plurality of signal processing units capable of exchanging data with tags operating in a plurality of standards, a plurality of RFID systems can be constructed with one reader / writer. Versatility and flexibility can be improved. Further, even in an environment where readers / writers operating in different forms are installed, data communication with a plurality of readers / writers can be performed using one tag, so that a plurality of tags suitable for each form are held. This eliminates the need to perform, and can enhance the convenience for the user.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
In a preferred embodiment of the RFID tag according to the present invention, a plurality of antennas are arranged in one tag, and each antenna is provided with an IC conforming to a different standard such as an IC conforming to ISO15693 or an IC conforming to ISO14443. A structure in which a plurality of antennas are arranged such that a small spiral antenna coil is arranged inside a large spiral antenna coil (FIG. 2), and a predetermined interval is set without overlapping the two spiral antenna coils. Open side-by-side structure (Fig. 3), structure in which two spiral antenna coils are superposed on each other via a seal made of soft magnetic material, conductive material and soft magnetic material (Fig. 4), two spiral shapes Structure in which a part of the antenna coil is superimposed and displaced via the above-mentioned seal made of soft magnetic material or conductive material and soft magnetic material (FIG. 8). (FIG. 9), a structure in which conductors are wound so as to be orthogonal to each other on a flat magnetic core (FIG. 10), A structure in which two antennas each having a rectangular shape are provided, and antennas each of which is wound with a lead wire are arranged side by side or superposed so that their antenna axes are parallel or orthogonal (FIGS. 11 to 14), etc. It is possible to suppress the mutual interference between the two antennas and construct an RFID system that can be used in different forms such as a proximity type and a proximity type.
[0023]
【Example】
In order to describe the above-described embodiment of the present invention in more detail, examples of the present invention will be described.
[0024]
[Example 1]
First, a tag, a reader / writer, and an RFID system according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram schematically showing the configuration of the RFID system of the present invention, and FIG. 2 is a diagram showing the structure of the antenna coil of the tag according to the first embodiment.
[0025]
As shown in FIG. 1, an RFID system 1 of the present invention includes a reader / writer 3 (or a reader, which will be described as a reader / writer hereinafter) that performs data communication using a reader / writer antenna 4, and a card. The tag / tag 2 has various shapes such as a mold, a label, a sheet, and a stick. The reader / writer 3 has a plurality of forms (for example, a proximity type which operates in accordance with a standard conforming to ISO15693 and a conformance with ISO14443. A plurality of signal processing circuits such as a communication circuit for converting a transmission / reception signal and an arithmetic processing circuit for decoding the transmission / reception signal (a first signal processing unit 5a in the figure) for use in a proximity type or the like operating according to a standard. And the second signal processing unit 5b). Although a plurality of signal processing units are provided in one reader / writer in the figure, a plurality of reader / writers may be provided for each mode.
[0026]
As shown in FIG. 2, the tag 2 of the present embodiment has two types of spiral antenna coils and two types of ICs on a base plate 7 made of an insulating film, a substrate, and the like. Other components such as a capacitor are omitted for the sake of simplicity. The following embodiments are also the same), and a small spiral second antenna is provided inside a large spiral antenna coil 8a. A coil 8b is disposed. For example, a first IC 9a compliant with ISO15693 is connected to the first antenna coil 8a to form a first communication unit 6a, and a second IC 9b compliant with ISO14443 is configured as the second antenna coil 8b. The second communication unit 6b is connected to the second communication unit 6b, and can operate in two forms of a proximity type and a proximity type using one tag 2.
[0027]
In the figure, the configuration is such that the spiral winding is wound twice, but the structure of the antenna coil is not limited to the configuration shown in the figure, and is formed on the base plate 7 so that the windings do not cross each other. The size, shape, number of turns, line width, and the like can be appropriately set in consideration of performance, standards, and the like required for the RFID system 1. As a method of forming this antenna coil, a structure in which a conductive material whose surface is covered with an insulating layer is attached to the base plate 7 or a metal film such as an aluminum foil or a copper foil is formed on an insulating film or the like, and etching or the like is performed. Any method can be used, such as forming a spiral antenna coil by a punching method or the like.
[0028]
In order to confirm the performance of the tag 2 having the above-described structure, the first antenna coil 8a and the second antenna coil 8b operate simultaneously with a single working distance when the dimensions (length and width) and the number of turns are changed. The working distance was measured. Table 1 shows the results.
[0029]
[Table 1]

[0030]
From Table 1, when the dimensions of the first antenna coil 8a and the second antenna coil 8b are the same (both 75 mm in length and 45 mm in width), both antennas interfere and the working distance is extremely short. On the other hand, when the size of the second antenna coil 8b is reduced and the second antenna coil 8b is arranged inside the first antenna coil 8a, the working distance is shorter than when the antenna is operated alone, but the first communication unit 6a ( A working distance of 55 to 70 mm for ISO15693) and a working distance of 4 to 8 mm for the second communication unit 6b (ISO14443) can be secured, and a plurality of antennas can coexist in one tag 2. I understand.
[0031]
As described above, in the above structure, the interference between the two resonance circuits can be suppressed to an acceptable level. However, when the working distance of ISO15693 is increased, the working distance of ISO14443 is shortened. However, it has a feature that the tag 2 can be made small because the structure is simple and the manufacturing is easy, and the area of the two antennas can be overlapped. In addition, since the direction in which the working distance becomes the longest is the same as that of the air core coil tag that is widely used at present, the user can easily learn when using the tag as an ID card or the like.
[0032]
[Example 2]
Next, an RFID tag according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram illustrating the structure of the antenna coil of the tag according to the second embodiment.
[0033]
In the first embodiment, the second antenna coil 8b is installed inside the first antenna coil 8a, but it is preferable that the windings do not overlap to suppress mutual interference of the antennas. Therefore, in the present embodiment, as shown in FIG. 3, the first communication unit 6a including the first antenna coil 8a and the first IC 9a on the base plate 7, and the second communication unit including the second antenna coil 8b and the second IC 9b on the base plate 7. The parts 6b are arranged side by side at a predetermined interval (W).
[0034]
In the drawing, two antenna coils are formed so as to be symmetrical with substantially the same size, but the structure of each antenna coil is not limited to the configuration shown in the drawing, and each winding crosses over the base plate 7. As in the first embodiment, the size, shape, number of turns, line width, arrangement position, manufacturing method, and the like are determined in consideration of performance, standards, and the like required for the RFID system. It can be set appropriately.
[0035]
In order to confirm the performance of the tag having the above structure, the first antenna coil 8a having a length of 75 mm × width 45 mm and two turns and the second antenna coil 8b having a length of 45 mm × width 27 mm and four turns are used. The working distance was measured when the distance (W) between the line closest to the line was changed, and the working distance when the line was operated at the same time. Table 2 shows the results.
[0036]
[Table 2]

[0037]
According to Table 2, when the distance between the first antenna coil 8a and the second antenna coil 8b is 0 mm, both antennas interfere and the working distance is extremely short, but the working distance increases as the distance increases. You can see that it has become. In particular, at a distance of 40 mm, a working distance almost the same as that of the case of operating alone is obtained, and it can be seen that mutual interference of antennas is suppressed more than in the first embodiment.
[0038]
In this structure, the antenna coil occupies a large area in order to arrange the antenna coils at predetermined intervals, and when the size of the tag 2 is determined, the antenna coil must be reduced, and the working distance is slightly reduced. However, when the size limit is not severe, a good working distance can be obtained, and the antenna 2 can be used without changing the shape and structure of the existing antenna coil, so that the cost of the tag 2 can be reduced. is there.
[0039]
[Example 3]
Next, an RFID tag according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram illustrating the structure of the antenna coil of the tag according to the third embodiment, and FIG. 5 is a diagram illustrating the effect of the present embodiment. FIG. 6 is a diagram showing another structure of the seal used for the tag of this embodiment, and FIG. 7 is a diagram schematically showing the structure of the soft magnetic material used in this embodiment. This embodiment is characterized in that a seal including a soft magnetic material and a conductive material is provided to suppress interference between two antenna coils.
[0040]
As shown in FIG. 4, the tag 2 of the present embodiment includes a first communication unit 6a including a first antenna coil 8a and a first IC 9a on each of two base plates 7a and 7b, and a second antenna coil 8b. And a second communication section 6b (not shown) including a second IC 9b and two base plates 7a and 7b opposed to each other via a seal 10 formed by sandwiching a conductive material 12 between soft magnetic materials 11a and 11b. It is arranged. Also in the present embodiment, the structure of each antenna coil is not limited to the configuration shown in the drawing, and its size, shape, number of turns, line width, arrangement position, manufacturing method, and the like can be arbitrarily set.
[0041]
Here, when the two base plates 7a and 7b are arranged to face each other without the interposition of the seal 10, as shown in FIG. 5B, the magnetic flux 13a of the first antenna coil 8a and the second antenna coil 8b The magnetic flux 13b interlinks and causes interference, but by interposing the seal 10 composed of the soft magnetic material 11a / conductive material 12 / soft magnetic material 11b, as shown in FIG. Since the magnetic flux 13 of the antenna coil passes through the soft magnetic material 11a or 11b and escapes almost in parallel from its end face, it is possible to prevent the magnetic flux of both antenna coils from interlinking and to suppress mutual interference between antennas. Can be.
[0042]
Here, in the case of the structure in which the seal 10 is interposed, the antenna coil can be overlapped, so that the size of the antenna coil can be increased as compared with the second embodiment. The working distance is slightly reduced to shield the radio wave from the third. In this case, for example, as shown in FIG. 6, a structure is provided in which a hole 14 is provided at the center of the conductive material 12 (substantially at the center of the antenna coil), or the thickness of the conductive material 12 is reduced. If the shielding of the radio wave from the writer 3 is reduced, the working distance can be improved. The working distance does not change even if a hole is provided in the center of the soft magnetic materials 11a and 11b. For this reason, a hole may be formed in the center portion to save the soft magnetic materials 11a and 11b. Also, after laminating the soft magnetic materials 11a and 11b and the conductive material 12, a method such as punching the laminated material is used. Holes 14 may be provided.
[0043]
When the conductive material 12 exceeds 300 μm, radio waves do not pass at all, so that only the radio wave of the reader / writer 3 wrapping around the conductive material 12 reaches the antenna coil, so that the working distance is reduced. When the conductive material 12 is an extremely thin film (for example, a film having a thickness of about 0.1 μm) formed by sputtering or the like, the loss of the resistance increases the loss of the antenna coil. In consideration of the above shielding effect, loss of resistance, availability of materials, and the like, the conductive material 12 has a thickness of about 5 μm to 300 μm, preferably about 8 μm to 20 μm, which is widely used as an aluminum foil. is there.
[0044]
The soft magnetic material is a rapidly solidified material of amorphous alloy, permalloy, electromagnetic steel, silicon iron, sendust alloy, Fe-Al alloy or soft magnetic ferrite, a cast material, a rolled material, a forged material or a sintered material, or an amorphous foil. Or, a laminated material of amorphous foil, metal powder, carbonyl iron powder, reduced iron powder, atomized powder (pure iron, iron including Si, Cr, Al, etc., permalloy, Co-Fe, etc.), amorphous powder (B, P, A composite material of a granular powder or flake such as iron, Co, or Ni containing water containing Si, Cr, etc. and an organic substance such as plastic or rubber, or a paint containing the above powder or flake. It may be a coating film.
[0045]
Injection molding, coating, compression molding, rolling and the like can be used as a method for producing the composite material. A soft magnetic material formed by injection molding or compression molding is tougher than a material formed of ferrite, and thus has a feature that it is hard to crack even when thinned. In the case of application, for example, after the granular powder is flattened by an attritor, a ball mill, a stamp mill or the like to form flakes, the coating containing the flakes or the granular powder can be repeatedly applied / dried on a film to be formed. In this case, by applying a magnetic field during coating, the flakes can be oriented in a certain direction, and the characteristics can be improved.
[0046]
Further, as the plastic in the composite material, a thermoplastic plastic having good workability or a thermosetting plastic having good heat resistance can be used, and acrylic, polyester, or polychlorinated having insulating properties can be used. Resins such as vinyl, polyethylene, polystyrene, and epoxy can also be used.
[0047]
The above various materials and manufacturing methods can be appropriately selected according to the performance required of the tag 2. For example, in the case of a composite material, a structure as shown in FIG. 7A is obtained, and powder and flakes 15 are dispersed in a resin binder 16 such as plastic or rubber, and the powder or flakes 15 are insulated from each other. Therefore, the soft magnetic material as a whole does not have conductivity, and can reduce eddy current loss even when receiving high-frequency radio waves, which is desirable as a material used in the structure of the present invention. Further, in the case of the laminated material of the amorphous foil, as shown in FIG. 7B, the structure is such that the amorphous foil 17 and the insulating layer 18 are alternately laminated. There is a problem of being large.
[0048]
In order to confirm the performance of the tag having the above structure, the working distance when the thickness of the conductive material 12 was changed and the working distance when the hole was provided and when the tag was operated simultaneously were measured. In addition, in order to confirm the effect of the seal 10, a tag without the seal 10 was similarly measured. Table 3 shows the results. In this experiment, a composite material containing flakes was used as the soft magnetic material, a material processed to a thickness of 0.5 mm by rolling, aluminum was used as the conductive material 12, and samples (A) and (B) were used. Was 0.1 mm in thickness, and the sample (C) was 0.013 mm in thickness. The dimensions of the holes 14 provided in the samples (B) and (C) were 55 mm × 25 mm.
[0049]
[Table 3]

[0050]
From Table 3, it can be seen that the working distance is extremely short for both antennas in the sample without the seal 10, but the working distance is greatly improved by interposing the seal 10. In addition, as compared with the sample (A) in which the conductive material 12 is provided on the entire surface, the sample (A) in which the hole 14 of 55 mm × 25 mm is provided in the substantially central portion of the conductive material 12 has a longer operating distance. Further, it can be seen that the working distance is further increased in the sample (C) in which the thickness of the conductive material 12 in the sample (B) is reduced.
[0051]
As described above, in the structure of the present embodiment, even if the tag 2 is small, the working distance can be relatively increased, and particularly, if the hole 14 is provided in the conductive material 12, the working distance can be further increased.
[0052]
[Example 4]
Next, an RFID tag according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a diagram illustrating the structure of the antenna coil of the tag according to the fourth embodiment.
[0053]
As shown in FIG. 8, the tag 2 of this embodiment includes a first communication unit 6a including a first antenna coil 8a and a first IC 9a on each of two base plates 7a and 7b, and a second antenna coil 8b. And a second communication section 6b including a second IC 9b, the antenna coils are arranged to be shifted from each other, and the flat soft magnetic material 11 is arranged only in a region where the antenna coils overlap. Also in the present embodiment, the structure of each antenna coil is not limited to the configuration shown in the drawing, and its size, shape, number of turns, line width, arrangement position, manufacturing method, and the like can be arbitrarily set. Further, similarly to the third embodiment, the seal 10 formed by sandwiching the conductive material 12 between the soft magnetic materials 11a and 11b may be arranged in a region where the antenna coil overlaps.
[0054]
In the above configuration, since the soft magnetic material 11 is provided only at the portion where the magnetic flux links, the shielding of the radio wave from the reader / writer 3 can be suppressed. In order to confirm the performance of the tag having the above structure, a first antenna coil 7a having a length of 45 mm × 45 mm and four turns is formed on the first base plate 7a, and a first IC 9a based on ISO15693 is connected to the first base plate 7a. A second antenna coil 7b having a length of 45 mm x a width of 45 mm and three turns is formed on the base plate 7b, a second IC 9b compliant with ISO14443 is connected, and the respective antenna coils are displaced to face each other. A sample on which the soft magnetic material 11 was arranged was prepared, and the working distance was measured. Table 4 shows the results. As the soft magnetic material 11, a composite material made of Fe-Cr-Si-based flakes and plastic was used, and a coating material obtained by applying a composite material having a thickness of 100 μm to PET having a thickness of 50 μm was used.
[0055]
[Table 4]

[0056]
From Table 4, the working distance of the first communication unit 6a is 250 mm, the working distance of the second communication unit 6b is 23 mm, and the working distance is smaller than that of the third embodiment in which the seal 10 is arranged on the entire surface of the antenna coil. It can be seen that it has been further improved.
[0057]
As described above, in the structure of this embodiment, the working distance can be made longer than that of the first to third embodiments, and is equivalent to the case where each tag 2 is operated independently, that is, each IC is air-core. This is an optimal method because it has the same working distance as the tag connected to the spiral antenna. In addition, since the direction in which the working distance becomes the longest is the same as the air core coil tag that is currently widely used, when used as an ID card or the like, there is also a feature that the user can easily learn. Since the directions in which the working distances of the two ICs are maximum are the same, the two ICs can be used without being conscious of which IC is to be operated.
[0058]
[Example 5]
Next, an RFID tag according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a diagram illustrating the structure of the antenna coil of the tag according to the fifth embodiment. This embodiment is characterized in that an antenna coil formed in a spiral shape on a base plate and an antenna coil formed by winding a conductive wire around a magnetic core are mixed.
[0059]
As shown in FIG. 9, the tag 2 of this embodiment is provided with a first communication unit 6 a including a spiral first antenna coil 8 a and a first IC 9 a on a base plate 7, and the inside of the first antenna coil 8 a. In addition, a second communication unit 6b in which a second antenna coil 8b is wound around a magnetic core 19 made of a flat soft magnetic material and a second IC 9b is connected is arranged. Also in the present embodiment, the structure of each antenna coil is not limited to the configuration shown in the drawing, and its size, shape, number of turns, line width, arrangement position, manufacturing method, and the like can be arbitrarily set.
[0060]
In order to confirm the performance of the tag having the above structure, a first IC 9a based on ISO15693 is connected to a spiral first antenna coil 8a having a length of 75 mm × a width of 45 mm and two turns, and the inside of the first antenna coil 8a is connected. At a substantially central portion, a second antenna coil 8b is formed by winding a foil wire five times around a magnetic core 19 made of a composite material having a width of 40 mm × a length of 25 mm and a thickness of 0.5 mm, and a second IC 9b compliant with ISO14443 is connected. A working sample was prepared and its working distance was measured. As a result, the working distance of the first communication unit 6a (ISO15693) is 210 mm, and the working distance of the second communication unit 6b (ISO14443) is 20 mm, and a working distance close to that of the fourth embodiment can be obtained. Was.
[0061]
As described above, even in the structure in which the spiral antenna and the antenna in which the conductor is wound around the magnetic core are mixed as in the present embodiment, the mutual interference of the antennas can be suppressed and the working distance of each communication unit can be increased. . Further, in such a configuration, since the direction in which the working distance becomes maximum is a direction substantially orthogonal to each communication unit, there is a feature that the direction in which a desired IC is operated can be consciously selected.
[0062]
[Example 6]
Next, an RFID tag according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a diagram illustrating the structure of the antenna coil of the tag according to the sixth embodiment. This embodiment is characterized in that a conductor is wound around a flat magnetic core in a direction orthogonal to each other to form an antenna coil.
[0063]
As shown in FIG. 10, the tag 2 of the present embodiment winds the first antenna coil 8 a around the magnetic core 19 made of a flat soft magnetic material in one direction (in the figure, the direction from the near side to the far side). A first communication unit 6a to which the first IC 9a is connected by rotation is formed, and a second communication unit 6b to which the second IC 9b is connected by winding the second antenna coil 8b in a direction orthogonal to the left and right (in the drawing). . Also in the present embodiment, the structure of each antenna coil is not limited to the configuration shown in the drawing, and its size, shape, number of turns, line width, arrangement position, manufacturing method, and the like can be arbitrarily set.
[0064]
In order to confirm the performance of the tag 2 having the above structure, a 35 μm thick, 1 mm wide foil wire is wound 10 times around a magnetic core 19 made of a composite material containing flakes of 40 mm wide × 40 mm long, 0.5 mm thick. To form a first antenna coil 8a, connect a first IC 9a based on ISO15693, and wind a foil wire having a thickness of 35 μm and a width of 1 mm five times in a direction orthogonal to the first antenna coil 8a to form a second antenna coil 8b. Was formed to prepare a sample to which the second IC 9b compliant with ISO14443 was connected, and the working distance was measured. As a result, the working distance of the first communication unit 6a (ISO15693) was 115 mm, and the working distance of the second communication unit 6b (ISO14443) was 15 mm.
[0065]
As described above, even in the structure of the present embodiment in which the conductor is wound in a different direction around one magnetic core, the mutual interference of the antennas can be suppressed and the working distance of each communication unit can be increased. Since the maximum directions are orthogonal to each other, it is possible to consciously select a direction for operating a desired IC. For example, since the direction in which the working distance is the longest is parallel to the surface of the tag 2, when passing through a gate in which a rectangular air-core antenna is arranged on the side surface, the antenna axis of the first communication unit 6a is placed horizontally in the chest pocket. If the tag 2 is passed through the gate in such a way that the working distance becomes the longest, the tag 2 can be detected without taking it out of the pocket.
[0066]
[Example 7]
Next, an RFID tag according to a seventh embodiment of the present invention will be described with reference to FIGS. 11 to 14 are views showing the structure of the antenna coil of the tag according to the seventh embodiment. This embodiment is characterized in that a conductor is wound around each of two flat magnetic cores to form an antenna coil.
[0067]
As shown in FIG. 11, the tag 2 according to the present embodiment includes a first communication unit 6a in which a first antenna coil 8a is wound around a first magnetic core 19a made of a soft magnetic material having a flat plate shape and a first IC 9a is connected thereto. Similarly, a second communication core 6b in which a second antenna coil 8b is wound around a second magnetic core 19b made of a soft magnetic material having a flat plate shape and a second IC 9b is connected is arranged. Also in the present embodiment, the structure of each antenna coil is not limited to the configuration shown in the drawing, and its size, shape, number of turns, line width, arrangement position, manufacturing method, and the like can be arbitrarily set.
[0068]
In order to confirm the performance of the tag having the above structure, two magnetic cores made of a composite material including flakes having a width of 20 mm × a length of 70 mm and a thickness of 0.5 mm were provided, and one of them was a foil having a thickness of 35 μm and a width of 1 mm. The first antenna coil 8a is formed by winding the wire 15 times, and the first IC 9a conforming to ISO15693 is connected thereto. The other antenna coil 8b is formed by winding the same 35 mm thick and 1 mm wide foil wire on the other side. Then, a second IC 9b based on ISO14443 was connected, a sample was prepared in which the respective magnetic cores were arranged in parallel on the same plane, and the working distance was measured. As a result, the working distance of the first communication unit 6a (ISO15693) was 75 mm, and the working distance of the second communication unit 6b (ISO14443) was 10 mm.
[0069]
As another form of the structure using two magnetic cores, as shown in FIG. 12, a first antenna coil 8a is wound around a first magnetic core 19a made of a flat soft magnetic material, and a first IC 9a is connected. The first communication unit 6a and the second communication unit 6b in which the second antenna coil 8b is wound around the second magnetic core 19b also made of a soft magnetic material having a flat plate shape and the second IC 9b is connected to the first communication unit 6a are arranged so as to overlap each other. Can be.
[0070]
In order to confirm the performance of the tag having the above structure, two composite materials including flakes having a width of 40 mm x a length of 70 mm and a thickness of 0.5 mm were provided, and one of the foils having a thickness of 35 μm and a width of 1 mm was wound 10 times. To form a first antenna coil 8a to connect to a first IC 9a according to ISO15693, and to the other side, wind a foil wire having a thickness of 35 μm and a width of 1 mm five times to form a second antenna coil 8b to form a second IC9b according to ISO14443. A sample was prepared in which the magnetic cores were connected to each other and the magnetic core surfaces were opposed to each other, and the working distance was measured. As a result, the working distance of the first communication unit 6a (ISO15693) was 120 mm, and the working distance of the second communication unit 6b (ISO14443) was 15 mm.
[0071]
As described above, in the structure of the present embodiment, a certain working distance can be secured without separating the two communication units by the seal 10 or the like. In this case, the structure of FIG. 12 can increase the working distance because the area of the antenna coil can be increased, but the thickness is increased when a card-type tag is used because two magnetic cores need to be stacked. There are drawbacks. Which type of tag to use can be set in consideration of the performance and usage required of the RFID system.
[0072]
In FIGS. 11 and 12, a foil wire is wound around each of the two magnetic cores in the same direction. However, a foil wire may be wound around each of the magnetic cores in a direction perpendicular to the respective magnetic cores. For example, a structure in which antennas having foil wires wound in mutually orthogonal directions are superposed (see FIG. 13), or a structure in which antennas having foil wires wound in mutually orthogonal directions are arranged in parallel on the same plane (see FIG. 14) ). Even in the case of such a structure, a certain working distance can be ensured without separating the two communication units by the seal 10 or the like, and by making the antenna axes orthogonal to each other, Similarly, the direction in which a desired IC operates can be consciously selected.
[0073]
In each of the above embodiments, the tag 2 includes two types of the first communication unit 6a including the first antenna coil 8a and the first IC 9a, and the second communication unit 6b including the second antenna coil 8b and the second IC 9b. However, the number of communication units is not limited to two, but may be any number, and the standard of each communication unit is not limited to the proximity type (ISO15693) or the proximity type (ISO14443). Anything that conforms to the standard may be used. In the above-described embodiment, the tag antenna used in the RFID system is described. However, the present invention is not limited to the above-described embodiment, and an arbitrary antenna that is required to arrange a plurality of antennas conforming to different standards is required. Can be applied to the system.
[0074]
【The invention's effect】
As described above, according to the RFID tag of the present invention, the reader / writer for performing data communication with the tag, and the RFID system including the tag, the same tag can be used in a different form (for example, a proximity type (ISO15693)). ) And a proximity type (such as ISO14443)).
[0075]
The reason is that as a tag antenna, a structure in which a small spiral antenna is arranged inside a large spiral antenna (FIG. 2), and a structure in which antennas suitable for each form are arranged at predetermined intervals (FIG. 2). FIG. 3), a structure in which the antennas formed on each base plate are opposed to each other with a seal made of soft magnetic material / conductive material / soft magnetic material therebetween (FIG. 4), and the antennas formed on each base plate are displaced and opposed. , A structure in which a seal is inserted therebetween (FIG. 8), a structure in which a conductive wire is wound around a flat magnetic core inside a spiral antenna (FIG. 9), and which are orthogonal to the flat magnetic core. (Fig. 10) A structure in which two flat magnetic cores are wound with conductors in the same direction or in a direction orthogonal to each other, and the antennas are arranged side by side or superposed on each other (Fig. 10). 11 to figure 4), and by connecting the IC conforming to different standards in each antenna, suppresses the interaction of the antenna, it is possible to form a communication unit which operates in different forms in the same tag.
[0076]
By using an RFID system including such a tag and a reader / writer including a signal processing unit that processes a signal of a different standard, for example, the RFID system can be used in either a proximity type or a proximity type. Becomes possible. In addition, the same tag enables data communication with different reader / writers by utilizing the difference in communication distance and antenna axis direction, and it is necessary to prepare a plurality of tags and reader / writers according to the usage form. As a result, the versatility, flexibility and expandability of the RFID system can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of an RFID system according to the present invention.
FIG. 2 is a plan view showing the structure of the tag according to the first embodiment of the present invention.
FIG. 3 is a plan view showing a structure of a tag according to a second embodiment of the present invention.
4A and 4B are diagrams showing a structure of a tag according to a third embodiment of the present invention, wherein FIG. 4A is a perspective view, and FIG. 4B is a cross-sectional view taken along line AA ′.
FIGS. 5A and 5B are diagrams for explaining the effect of the tag according to the third embodiment of the present invention, wherein FIG. 5A shows the magnetic flux of the tag of the present embodiment, and FIG. FIG.
FIGS. 6A and 6B are diagrams showing another structure of the seal used for the tag according to the third embodiment of the present invention, wherein FIG. 6A is a perspective view and FIG. 6B is a cross-sectional view taken along line BB ′.
FIG. 7 is a diagram schematically showing a structure of a soft magnetic material used in the present invention.
FIGS. 8A and 8B are views showing the structure of a tag according to a fourth embodiment of the present invention, wherein FIG. 8A is a perspective view and FIG. 8B is a cross-sectional view taken along line CC ′.
FIG. 9 is a perspective view showing a structure of a tag according to a fifth embodiment of the present invention.
FIG. 10 is a perspective view illustrating a structure of a tag according to a sixth embodiment of the present invention.
FIG. 11 is a perspective view illustrating a structure of a tag according to a seventh embodiment of the present invention.
FIG. 12 is a perspective view showing another structure of the tag according to the seventh embodiment of the present invention.
FIG. 13 is a perspective view showing another structure of the tag according to the seventh embodiment of the present invention.
FIG. 14 is a perspective view showing another structure of the tag according to the seventh embodiment of the present invention.
[Explanation of symbols]
1 RFID system
2 tags
3 Reader / writer
4 Reader / writer antenna
5 Signal processing unit
6a First communication unit
6b Second communication unit
7 Base plate
7a First base plate
7b Second base plate
8a 1st antenna coil (for proximity type (ISO15693))
8b 2nd antenna coil (for proximity type (ISO14443))
9a 1st IC (for proximity type (ISO15693))
9b 2nd IC (for proximity type (ISO14443))
10 seals
11, 11a, 11b Soft magnetic material
12 conductive material
13, 13a, 13b Magnetic flux
14 holes
15 flakes
16 Resin binder
17 Amorphous foil
18 Insulating layer
19 magnetic core
19a 1st magnetic core
19b 2nd magnetic core

Claims (19)

A tag for exchanging data with a reader or reader / writer without contact,
A tag comprising a plurality of antennas and a plurality of ICs connected to the plurality of antennas and conforming to different standards, in one tag. A tag for exchanging data with a reader or reader / writer without contact,
In one tag, two antennas made of a spiral conductive wire are arranged on the same plane, and each of the two antennas is connected to an IC conforming to a different standard. . The tag according to claim 2, wherein one of the two antennas is arranged inside the other antenna. The tag according to claim 2, wherein the two antennas are arranged side by side at a predetermined interval. A tag for communicating data with a reader or reader / writer without contact,
In one tag, there are provided two antennas made of a spiral-shaped conductive wire, and each of the antennas is arranged so as to face each other via a separation layer having a three-layer structure in which a conductive material is sandwiched between soft magnetic materials. An IC compliant with different standards is connected to each of the two antennas. The two antennas are displaced in the direction of the antenna surface so that a part of the two antennas overlap when viewed from a direction orthogonal to the antenna surface, and the separation layer is disposed at least in the overlapping region. The tag according to claim 5, wherein the tag is provided. 6. A hole in which the conductive material is not provided is formed at a substantially central portion of a region surrounded by the two antennas when viewed from a direction perpendicular to the antenna surface. 6. The tag according to 6. The tag according to any one of claims 5 to 7, wherein the conductive material is made of an aluminum plate or foil, or a copper plate or foil. 9. The tag according to claim 8, wherein the thickness of the conductive material is set to approximately 5 μm to 300 μm, preferably approximately 8 μm to 20 μm. A tag for communicating data with a reader or reader / writer without contact,
In one tag, there are provided two antennas made of a spiral conductive wire, and the two antennas are arranged such that when viewed from a direction orthogonal to the antenna surface, the two antennas overlap each other so that a part of the two antennas overlap each other. A tag that is arranged in a direction shifted from each other, a flat soft magnetic material is provided at least in the overlapping area, and an IC conforming to different standards is connected to each of the two antennas. . A tag for communicating data with a reader or reader / writer without contact,
In one tag, there is provided a first antenna made of a spiral conductive wire, and a second antenna formed by winding a conductive wire around a magnetic core made of a flat soft magnetic material, and each of the two antennas Is a tag to which ICs conforming to different standards are connected. The second antenna is characterized in that it is arranged inside the first antenna and such that the plane of the flat magnetic core is substantially parallel to the antenna surface of the first antenna. The tag according to claim 11. A tag for communicating data with a reader or reader / writer without contact,
In one tag, there are provided two antennas each having a conductor wound in a different direction around a magnetic core made of a flat soft magnetic material, and an IC conforming to different standards is connected to each of the two antennas. Tags characterized by the following. A tag for communicating data with a reader or reader / writer without contact,
In one tag, there are provided two antennas each formed by winding a conductive wire around each of two magnetic cores made of a soft magnetic material in a plate shape, and an IC conforming to different standards is connected to each of the two antennas. A tag characterized by being performed. 15. The RFID tag according to claim 14, wherein the conductive wire is wound around the two antennas such that respective antenna axes are substantially parallel or substantially orthogonal. The tag according to any one of claims 5 to 15, wherein the soft magnetic material is a composite material of soft magnetic flakes or soft magnetic powder and plastic or rubber. The tag according to any one of claims 1 to 16, wherein the IC includes an IC compliant with ISO15693 and an IC compliant with ISO14443. A reader or reader / writer for communicating with the tag according to any one of claims 1 to 17,
A reader or a reader / writer, comprising: a plurality of signal processing units capable of communicating data with each of the ICs conforming to the different standards. An RFID system comprising the tag according to any one of claims 1 to 17 and a reader or a reader / writer,
Using a plurality of antennas formed in one tag and a plurality of communication units each constituted by a plurality of ICs conforming to different standards, data communication in a plurality of forms having different working distances or different data communication speeds. RFID system.

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