JP2004355212A

JP2004355212A - Non-contact type ic card reader/writer and adjusting method therefor

Info

Publication number: JP2004355212A
Application number: JP2003150660A
Authority: JP
Inventors: Hiroshi Yoshinaga; 洋吉永; Futoshi Deguchi; 太志出口; Masahiko Tanaka; 雅彦田中; Akihiko Hirata; 明彦平田; Sukeaki Haruyama; 祐明春山
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-05-28
Filing date: 2003-05-28
Publication date: 2004-12-16
Anticipated expiration: 2023-05-28
Also published as: JP4172327B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact type IC card reader/writer which can automatically adjust the impedance of an antenna and R/W transmitting power, and an adjusting method thereof. <P>SOLUTION: The non-contact type IC card reader/writer which is supplied with electric power and conducts data transmission using radio waves comprises a transmitting part and an antenna part. The device also comprises a detecting circuit which detects a current in the transmitting part, and varies a circuit constant of an antenna resonance circuit of the antenna part corresponding to a current level obtained by the detecting circuit to automatically adjust resonance frequency and impedance of the antenna without using an computer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、電磁波を使用した非接触ＩＣカードリード／ライト装置及びその調整方法に関する。
【０００２】
【従来の技術】
従来、ＩＣカードを用いた読取／書込（リード／ライト、以下、Ｒ／Ｗと省略することもある）システムは、一般に非接触ＩＣカードシステムと呼ばれ、例えば１３．５６ＭＨｚの周波数帯を利用した入退出管理システム、物流システム、等々に実用化されている。
【０００３】
このシステムは、図１２に示すように、１枚の樹脂製カード上にＩＣチップ２２とアンテナコイル２３を備えた非接触ＩＣカード２１と、この非接触ＩＣカード２１との通信を行うＲ／Ｗ装置２６とを備えている。Ｒ／Ｗ装置２６は、本体部２５にアンテナ部２４が接続され、更に、パソコン２７に接続されて構成されている。そして、アンテナ部２４により電力と送信データを常時または間欠に送信し、この電力と送信データを受信できる範囲内にある非接触ＩＣカード２１からの受信データを得るものである。なお、図１２は、非接触ＩＣカードシステムの説明図である。
【０００４】
非接触ＩＣカードを用いた個人認識システムは、磁気ストライプカードのようにカードデータの書き込み及び読み取りの際にカードリーダにカードを挿入する必要がなく、利便性に優れており、ビルなどの出入管理システムに用いる個人識別媒体として、使われることが多くなってきている。特に、非接触カードを名札ないしは身分証明書と兼ねて胸などにつけておくシステムでは、ドアの前に設置されたＲ／Ｗ装置に近づくだけでドアの電気錠が解錠され、ドアを開けることが出来る点が評価されている。
【０００５】
例えば、（特許文献１）に示される出入管理システムがあるが、このような出入管理システムに用いられるＲ／Ｗ装置のアンテナ部は、一般的には、オフィスの出入口ドア近辺の壁面に露出あるいは壁に埋め込んで取り付けられる。しかし、この様な取付場所の周囲には他の機器に使用する電線や、コンクリートの補強のための鉄筋などがある場合が多い。
【０００６】
このように、Ｒ／Ｗ装置のアンテナ部を実際に設置する場合の周囲の条件は千差万別なのが実状であるにも拘らず、従来のＲ／Ｗ装置のアンテナ部は、自由空間においたときに最良の性能を発揮するように作られており、設置環境が変化すると、それに伴って非接触ＩＣカードデータの読み取り性能が大幅に低下してしまうものが殆どであった。
【０００７】
そこで、一般的には、Ｒ／Ｗ装置を実際に設置する際に、夫々の設置場所に応じて、夫々個々別にＲ／Ｗ装置のアンテナ部の共振周波数調整及びインピーダンス調整を行い、適正な通信距離の確保を行っているが、非常に手間のかかる作業であり、Ｒ／Ｗ装置設置における大きな問題点である。
【０００８】
そこで、（特許文献２）や（特許文献３）に示される遮蔽版を追加することでＲ／Ｗ装置のアンテナ部背面の設置環境の影響を和らげると共に、アンテナ設置場所でのアンテナ共振周波数の調整や通信距離の調整をする方法が考案されている。
【０００９】
更に、Ｒ／Ｗ装置のアンテナ部の設置環境の影響を少なくする別の方法として、（特許文献４）に示されるフェライト等の磁性体をアンテナの背面に付加する方法も考案されている。
【００１０】
また、Ｒ／Ｗ装置のアンテナ部の共振周波数及びインピーダンスが変化しても、送信パワーを調整して、適正な通信距離を確保する方法が、（特許文献５）に示される方法で考案されている。
【００１１】
【特許文献１】
特開平８−１０９７６４号公報
【特許文献２】
特開平８−２６３６０９号公報
【特許文献３】
特開２００１−４４７４７号公報
【特許文献４】
特開２００２−２９８０９５号公報
【特許文献５】
特開２０００−３５３２２２号公報
【００１２】
【発明が解決しようとする課題】
しかしながら、従来の方法は、非接触ＩＣカードとＲ／Ｗの通信距離が数ｍｍ程度の密着型（送信出力１０ｍＷ）や通信距離が１０ｃｍ程度の近接形（送信出力１Ｗ）では有効ではあるが、平成１４年度改訂の近傍型（送信出力４Ｗ）では、送信電力が大きいために従来の方法では対処できない課題が生じてしまうと言う問題がある。
【００１３】
近傍型では送信出力が大きい為、Ｒ／Ｗ部の送信部の発熱が重要な課題となる。発熱を少なくする為の手段としては、Ｒ／Ｗ部のアンテナと送信部のインピーダンス整合を確実に行い、アンテナのクオリティファクタを大きくしてアンテナ効率を高め、送信部のパワーアンプの電力効率を高める等の方法があるが、これらはひとつでも特性が悪くなると、全体的な電力効率が悪くなり、発熱の問題が生じる。特にアンテナの設置環境により、アンテナの共振周波数やアンテナのインピーダンスが変化し、Ｒ／Ｗ部の送信部とのインピーダンス整合が取れなくなると、通信距離の低下だけの問題ではなく、Ｒ／Ｗ送信部に過大な電流が流れ、Ｒ／Ｗ送信部の過熱及び破壊という大きな問題が生じてしまうと言う課題があった。
【００１４】
従来方法の手段としてＲ／Ｗアンテナ部に遮蔽板の付加があるが、近傍型では通信距離がＲ／Ｗ装置のアンテナの前面及び背面に夫々５０ｃｍ程度もあるので、Ｒ／Ｗアンテナ部と遮蔽板の距離を相当とらないと、磁束が遮蔽板により切られてしまい、通信距離が低下する。通信距離が低下しない様に遮蔽板を取りつけると、Ｒ／Ｗ装置のアンテナ部が構造的に厚くなり、遮蔽板は遠隔型には適切な手段とは言えない。
【００１５】
また、従来方法の他の手段としてフェライトの付加があるが、近傍型では通信距離がＲ／Ｗ装置のアンテナの前面及び背面に夫々５０ｃｍ程度もあるだけでは無く、同時にＲ／Ｗ装置のアンテナ部と水平方向の通信範囲も広く、アンテナ面積の４倍以上の通信範囲をもっている。従って、Ｒ／Ｗ装置のアンテナ部背面の影響を完全になくす為には非常に広いフェライトが必要である。Ｒ／Ｗ装置のアンテナ部の面積と同等程度の面積のフェライトでは、Ｒ／Ｗ装置のアンテナ部背面の金属の影響を受け、Ｒ／Ｗ装置のアンテナ部の共振周波数やアンテナインピーダンスが変化してしまい、過大な電流がＲ／Ｗ装置の送信部に流れ、Ｒ／Ｗ装置の送信部の異常発熱や破壊につながると言う課題があった。
【００１６】
更に、Ｒ／Ｗ装置のアンテナ部の共振周波数及びインピーダンスが変化しても、送信パワーを調整して、適正な通信距離を確保する方法であるが、遠隔型の様な大きな送信電力のＲ／Ｗ装置の場合、Ｒ／Ｗ装置の送信部とＲ／Ｗ装置のアンテナ部とのインピーダンス整合を良好に取らないと、過大な電流がＲ／Ｗ装置の送信部に流れ、Ｒ／Ｗ装置の送信部の異常発熱や破壊につながると言う課題があった。
【００１７】
そこで、本発明は、上記のような従来の技術における不具合を解消し、アンテナのインピーダンス調整及び、またはＲ／Ｗの送信パワーを最適に自動調整が可能な非接触ＩＣカードリード／ライト装置及びその調整方法を提供することを目的とする。
【００１８】
【課題を解決するための手段】
上記目的を達成するために、本発明は、電磁波により、データ通信及び電力供給を行なう非接触ＩＣカードリード／ライト装置であって、アンテナの共振周波数やアンテナインピーダンスを自動調整する構成としたものである。
【００１９】
そして、本発明はＲ／Ｗ装置の送信部に流れる電流を検出、もしくは、Ｒ／Ｗ送信部とＲ／Ｗアンテナ部間の進行波、反射波を検出する検出手段と、検出したレベルに応じてアンテナ共振整合回路の回路定数を調整し、アンテナのインピーダンスおよびアンテナ共振周波数を自動調整する手段を持つ事で、所望の周波数でのＲ／Ｗ送信部とＲ／Ｗアンテナ部のインピーダンス整合を取り、Ｒ／Ｗ送信部に過大な電流が流れ、Ｒ／Ｗ送信部が異常発熱したり、通信距離が低下する事を防ぐ事が出来、千差万別な設置場所でも最適な電力効率のＲ／Ｗ装置が得られる。
【００２０】
また、本発明は前記発明手段でＲ／Ｗ送信部とＲ／Ｗアンテナ部のインピーダンス整合およびアンテナ共振周波数を調整した後、Ｒ／Ｗ送信部とＲ／Ｗアンテナ部間の送信パワーレベルを検出する検出手段と、検出したレベルに応じてＲ／Ｗ送信部の送信パワーを調整する手段を持つ事で、千差万別な設置場所でも適正な通信距離を確保する事が出来るＲ／Ｗ装置が得られる。
【００２１】
また、本発明は前記発明手段でＲ／Ｗ送信部とＲ／Ｗアンテナ部の進行波、及び又は、反射波を検出する検出手段を持ち、検出したレベルに応じてアンテナ共振整合回路の回路定数を調整し、アンテナのインピーダンスおよびアンテナ共振周波数を自動調整する手段を持つ事で、Ｒ／Ｗ送信部とＲ／Ｗアンテナ部のインピーダンス整合およびアンテナ共振周波数を調整し、Ｒ／Ｗ送信部に過大な電流が流れ、Ｒ／Ｗ送信部が異常発熱したり、通信距離が低下する事を防ぐ事が出来、千差万別な設置場所でも最適な電力効率のＲ／Ｗ装置が得られる。
【００２２】
また、本発明は前記発明手段でＲ／Ｗ送信部とＲ／Ｗアンテナ部の進行波、及び又は、反射波を検出する検出手段を持ち、検出したレベルに応じてアンテナ共振整合回路の回路定数を調整し、アンテナのインピーダンスを自動調整する手段を持つ事で、Ｒ／Ｗ送信部とＲ／Ｗアンテナ部のインピーダンス整合およびアンテナ共振周波数を調整し、前記検出手段で送信パワーレベルを検出し、その検出したレベルに応じて、Ｒ／Ｗ部の送信パワーの調整を自動的に行うことで、Ｒ／Ｗ送信部に過大な電流が流れ、Ｒ／Ｗ送信部が異常発熱したり、通信距離が低下する事を防ぐ事が出来、千差万別な設置場所でも適正な電力効率と最適な通信距離を確保したＲ／Ｗ装置が得られる。
【００２３】
【発明の実施の形態】
以下、本発明の一実施の形態について図１から図１１を用いて説明する。
【００２４】
ここで、図１〜図１１は、それぞれ、本発明の実施の形態１〜１１によるＲ／Ｗ装置のブロック図である。
【００２５】
図１〜図１１において、１は発振器、２はパワーアンプ（以下、ＰＡと略す）である。また、３は電流検出回路、４は制御回路、５はアンテナ調整回路、６はアンテナであり、更に、７はＲ／Ｗ装置の送信部、８はＲ／Ｗ装置のアンテナ部、９はＲ／Ｗ装置の受信部である。また、１０はＲ／Ｗ装置を示す。
【００２６】
（実施の形態１）
図１において、発振器１で生み出された搬送波はパワーアンプ２（ＰＡ２）で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７にはＰＡ２の電流検出回路３を設け、ＰＡ２に流れる電流に応じて、アンテナ調整回路５の回路定数を制御し、ＰＡ２に流れる電流を最適値に制御することにより、Ｒ／Ｗ装置のアンテナ部８の設置環境に応じて、Ｒ／Ｗアンテナ部８の共振周波数調整およびインピーダンス調整を行い、所望の周波数でのＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取り、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、自動的に最適な電流値で、通信距離が確保できる様にしている。
【００２７】
（実施の形態２）
図２において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７にはＰＡ２の電流検出部３を設け、電流値に応じたデジタル信号がマイコン１３に入力される。マイコン１３はＰＡ２に流れる電流値に応じて、アンテナ調整回路５を制御し、ＰＡ２に流れる電流を最適値に制御することにより、Ｒ／Ｗ装置のアンテナ部８の設置環境に応じて、Ｒ／Ｗアンテナ部の共振周波数調整およびインピーダンス調整を行い、所望の周波数でのＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取り、Ｒ／Ｗ装置１０のアンテナを設置環境毎に個別に調整しなくても、自動的に最適な電流値で、通信距離が確保できる様にしている。
【００２８】
（実施の形態３）
図３において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７には送信部７とアンテナ部８間の進行波、反射波検出回路１４を設け、その検出された信号に応じて、制御回路４は所望の周波数で反射波が最小で進行波が最大になる様にアンテナ調整回路５を調整する。この様に調整する事でＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取る事が出来、Ｒ／Ｗ装置のアンテナ部８の設置環境によって、送信部７に過度の電流が流れるのを防ぎ、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、最適な電流で、通信距離が確保できる様にしている。
【００２９】
（実施の形態４）
図４において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７には送信部７とアンテナ部８間の進行波、反射波検出回路１４を設け、その検出された信号はマイコン１３に入力される。マイコン１３は、その検出された信号に応じて、所望の周波数で反射波が最小で進行波が最大になる様に制御回路４でアンテナ調整回路５を調整制御する。この様に調整する事でＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取る事が出来、Ｒ／Ｗ装置のアンテナ部８の設置環境によって、送信部７に過度の電流が流れるのを防ぎ、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、最適な電流で、通信距離が確保できる様にしている。
【００３０】
（実施の形態５）
図５において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７には送信部７とアンテナ部８間の進行波、反射波検出回路１４を設け、その検出された信号はＰＡ制御回路４に入力される。ＰＡ制御回路４は、その検出された信号に応じて、ＰＡ２の出力インピーダンスを調整して、アンテナ部８とインピーダンス整合を取ったり、送信出力を制御する事が出来る。この様に調整する事により、所望の周波数でＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取ったり、送信出力を制御する事が出来る為、Ｒ／Ｗ装置のアンテナ部８の設置環境によって、送信部７に過度の電流が流れるのを防ぎ、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、送信部７の最適な電流や送信出力で、通信距離が確保できる様にしている。
【００３１】
（実施の形態６）
図６において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７には送信部７とアンテナ部８間の進行波、反射波検出回路１４を設け、その検出された信号はマイコン１３に入力される。マイコン１３はその入力された信号に応じ、制御回路４を制御し、ＰＡ２の出力インピーダンスを調整して、アンテナ部８とインピーダンス整合を取ったり、送信出力を制御する事が出来る。この様に調整する事により、所望の周波数でＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取ったり、送信出力を制御する事が出来る為、Ｒ／Ｗ装置のアンテナ部８の設置環境によって、送信部７に過度の電流が流れるのを防ぎ、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、送信部９の最適な電流や送信出力で、通信距離が確保できる様にしている。
【００３２】
（実施の形態７）
図７において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７には送信部７とアンテナ部８間の進行波、反射波検出回路１４を設け、その検出された信号は制御回路４に入力される。制御回路４は搬送波発信回路である発振器１から発生した搬送波信号のデューティーを制御する。ＰＡ２が例えば、Ｅ級動作等のスイッチング増幅器の場合は増幅器に入力される信号のデューティーを制御する事により出力電力の制御が出来る。実施の形態７の例では、進行波、反射波検出回路１４で検出されたレベルに応じて、制御回路４がデューティー調整回路１５を制御し、Ｅ級動作アンプのＰＡ２の送信パワーを調整することができる為、Ｒ／Ｗ装置のアンテナ部８の設置環境によって、送信部７に過度の電流が流れ様とした場合、送信パワーを制御して、送信部７の過電流や発熱、破壊を自動的に防ぐ事が出きる様にしている。
【００３３】
（実施の形態８）
図８において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７には送信部７とアンテナ部８間の進行波、反射波検出回路１４を設け、その検出された信号はマイコン１３に入力される。マイコン１３はその入力された信号に応じ、制御回路４を介し、制御回路４を制御する。制御回路４は発振器１の搬送波信号のデューティーを制御する。ＰＡ２が例えば、Ｅ級動作等のスイッチング増幅器の場合は増幅器に入力される信号のデューティーを制御する事により出力電力の制御が出来る。実施の形態７の例では、進行波、反射波検出回路１４で検出されたレベルに応じて、制御回路４がデューティー調整回路１５を制御し、Ｅ級動作アンプＰＡ２の送信パワーを調整することができる為、Ｒ／Ｗ装置のアンテナ部８の設置環境によって、送信部７に過度の電流が流れ様とした場合、送信パワーを制御して、送信部７の過電流や発熱、破壊を自動的に防ぐ事が出きる様にしている。
【００３４】
（実施の形態９）
図９は実施の形態２と実施の形態８の組み合わせである。図９において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７にパワー検出回路１７を設け、その検出された信号はマイコン１３に入力される。また、送信部７のＰＡ２の電流を検出する電流検出回路部３を設け、その検出レベルはマイコン１３に入力される。マイコン１３はＰＡ２に流れる電流に応じて、アンテナ調整回路５を制御し、ＰＡ２に流れる電流を最適値に制御することで、Ｒ／Ｗ装置のアンテナ部８の設置環境に応じて、Ｒ／Ｗアンテナ部の共振周波数調整インピーダンス調整を行い、Ｒ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取る。次に、マイコン１３に入力されるパワー検出回路１７からの検出レベルに応じて、マイコン１３はデューティー調整回路１５を制御し、ＰＡ２の送信出力を初所定のレベルに調整する。この様にＲ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を自動的に取った後で、送信パワーを自動調整する事で、Ｒ／Ｗ装置の設置環境毎に、個別に調整夫々調整することなく、最適な電力効率で、最適なパワーで、最適な通信距離が確保できる様にしている。
【００３５】
（実施の形態１０）
図１０において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。ＡＭ変調方式のＲ／Ｗ装置においては、ＰＡ２の電源電圧を変化させる事でＡＭ変調を掛ける場合が多いが、この場合、ＡＭ変調器内の抵抗器の両端の電位差を見る事でＰＡ２に流れる電流を検出することができる。図１０の実施の形態１０の例ではパワー検出回路１７にて、ＡＭ変調と電流検出を行っている。検出された電流値はマイコン１３に入力される。マイコンはＰＡ２に流れる電流に応じて、アンテナ調整回路５を制御し、ＰＡ２に流れる電流を最適値に制御することで、Ｒ／Ｗ装置のアンテナ部８の設置環境に応じて、所望の周波数でのＲ／Ｗアンテナ部の共振周波数調整およびインピーダンス調整を行い、Ｒ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取り、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、自動的に最適な電流で、通信距離が確保できる様にしている。
【００３６】
（実施の形態１１）
図１１において、発振器１で生み出された搬送波はＰＡ２で必要な電力まで増幅され、アンテナ調整回路５を介してアンテナ６に供給され、磁束１１を生み出し、非接触ＩＣカード１２に電力と送信データが供給される。送信部７にはＰＡ２の電流検出３があり、マイコン１３に入力される。電流検出３の抵抗器はＰＡ２と電源の間に直列に挿入されている。この抵抗器の両端の電位差を読むことでＰＡ２に流れる電流を検出することができる。マイコンはＰＡ２に流れる電流に応じて、アンテナ調整回路５を制御し、ＰＡ２に流れる電流を最適値に制御することで、Ｒ／Ｗ装置のアンテナ部８の設置環境に応じて、所望の周波数でのＲ／Ｗアンテナ部の共振周波数調整およびインピーダンス調整を行い、Ｒ／Ｗ装置の送信部７とＲ／Ｗ装置のアンテナ部８のインピーダンス整合を取り、Ｒ／Ｗ装置のアンテナを設置環境毎に個別に調整しなくても、自動的に最適な電流で、通信距離が確保できる様にしている。
【００３７】
（実施の形態１２）
上記で説明した実施の形態１〜１１について、Ｒ／Ｗ装置のアンテナ設置の時にだけ動作させることで、Ｒ／Ｗ装置の設置環境に応じて、Ｒ／Ｗ装置のアンテナやＲ／Ｗ装置の送信出力が自動調整される為、従来の様にＲ／Ｗ装置のアンテナ取り付け時に行っていた、設置環境毎にＲ／Ｗ装置のアンテナの調整やＲ／Ｗ装置の送信出力調整をする事無く、簡便に設置することができる。設置以降の通常運用時はこれらの自動調整機能は動作させず、通常の非接触ＩＣカードＲ／Ｗ装置として動作させる。
【００３８】
（実施の形態１３）
上記で説明した実施の形態１〜１１について、Ｒ／Ｗ装置のアンテナ設置の時に動作させることで、Ｒ／Ｗ装置の設置環境に応じて、Ｒ／Ｗ装置のアンテナやＲ／Ｗ装置の送信出力が自動調整される為、従来の様にＲ／Ｗ装置のアンテナ取り付け時に行っていた、設置環境毎にＲ／Ｗ装置のアンテナの調整やＲ／Ｗ装置の送信出力調整をする事無く、簡便に設置することができる。また、設置以降の通常運用時もこれらの自動調整機能を動作させる。
【００３９】
これらの自動調整機能が無い、一般的なＲ／Ｗ装置では、外的要員等でアンテナ設置環境が変化した場合、アンテナのインピーダンスや共振周波数が変化し、電力効率が落ち、送信部に大きな電流が流れたり、通信距離が落ちたりする。しかし、これらの自動調整機能が常時機能していると、アンテナ設置環境が外的要員等で変化しても自動的に、アンテナのインピーダンス調整や共振周波数調整を行い、また送信パワー調整も自動的に行う為電力効率が落ち、送信部に大きな電流が流れ、通信距離が落ちる事無しに、常に最適な電力効率で、最適な通信距離を確保することが出来る。
【００４０】
以上、本発明の実施の形態１〜１３について説明したが、上述したように、発振器１からの搬送波は電力増幅器であるパワーアンプ２で増幅されるが、その増幅にはＥ級増幅器（Ｅクラスアンプ）を用いることが好ましい。Ｅ級増幅器を用いることによって、高効率動作を実現することが可能となる。よって、送信出力を上げても発熱を抑えることができる。
【００４１】
なお、本発明における非接触ＩＣカードの定義は、いわゆるカードに限定されるものではなく、非接触でＲ／Ｗ装置との通信を行うことができる無線通信媒体である。よって、用途によってはＩＣタグ、ＩＤタグ、識別ラベルと呼ばれるものを含む。
【００４２】
【発明の効果】
以上の様に本発明により、Ｒ／Ｗ装置の送信部に流れる電流を検出、もしくは、Ｒ／Ｗ送信部とＲ／Ｗアンテナ部間の進行波、反射波を検出する検出手段と、検出したレベルに応じてアンテナ共振回路の回路定数を自動調整し、アンテナのインピーダンスや共振周波数を自動調整する手段を持つ事で、Ｒ／Ｗ送信部とＲ／Ｗアンテナ部のインピーダンス整合を取り、また、送信パワー検出手段で送信パワーレベルを検出し、その検出したレベルに応じて、Ｒ／Ｗ部の送信パワーの調整を自動的に行うことで、アンテナ設置環境によっては、Ｒ／Ｗ送信部に過大な電流が流れたり、Ｒ／Ｗ送信部が異常発熱したり、通信距離が低下する事を防ぐ事が出来る為、千差万別な設置場所でも、個々にＲ／Ｗ装置を調整する事無く、自動的に適正な電力効率と最適な通信距離を確保したＲ／Ｗ装置が得られる。
【００４３】
よって、本発明によれば、アンテナのインピーダンス調整及び、またはＲ／Ｗの送信パワーを最適に自動調整が可能な非接触ＩＣカードリード／ライト装置及びその調整方法を提供することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１によるＲ／Ｗ装置のブロック図
【図２】本発明の実施の形態２によるＲ／Ｗ装置のブロック図
【図３】本発明の実施の形態３によるＲ／Ｗ装置のブロック図
【図４】本発明の実施の形態４によるＲ／Ｗ装置のブロック図
【図５】本発明の実施の形態５によるＲ／Ｗ装置のブロック図
【図６】本発明の実施の形態６によるＲ／Ｗ装置のブロック図
【図７】本発明の実施の形態７によるＲ／Ｗ装置のブロック図
【図８】本発明の実施の形態８によるＲ／Ｗ装置のブロック図
【図９】本発明の実施の形態９によるＲ／Ｗ装置のブロック図
【図１０】本発明の実施の形態１０によるＲ／Ｗ装置のブロック図
【図１１】本発明の実施の形態１１によるＲ／Ｗ装置のブロック図
【図１２】非接触ＩＣカードシステムの説明図
【符号の説明】
１発振器
２パワーアンプ
３電流検出回路
４制御回路
５アンテナ調整回路
６アンテナ
７送信部
８アンテナ部
９受信部
１０Ｒ／Ｗ装置
１１磁束
１２非接触ＩＣカード
１３マイコン
１４進行波、反射波検出回路
１５デューティー調整回路
１６制御回路
１７パワー検出回路
２１非接触ＩＣカード
２２ＩＣチップ
２３アンテナ
２４アンテナ部
２５本体部
２６Ｒ／Ｗ装置
２７パソコン[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-contact IC card read / write device using electromagnetic waves and a method for adjusting the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a read / write (read / write, hereinafter sometimes abbreviated as R / W) system using an IC card is generally called a non-contact IC card system, and uses a 13.56 MHz frequency band, for example. It has been put to practical use in entry / exit management systems, distribution systems, etc.
[0003]
As shown in FIG. 12, this system includes a non-contact IC card 21 having an IC chip 22 and an antenna coil 23 on one resin card, and an R / W for performing communication with the non-contact IC card 21. Device 26. The R / W device 26 is configured such that the antenna unit 24 is connected to the main unit 25 and further connected to the personal computer 27. Then, the power and the transmission data are transmitted constantly or intermittently by the antenna unit 24, and the reception data from the non-contact IC card 21 within a range where the power and the transmission data can be received is obtained. FIG. 12 is an explanatory diagram of the non-contact IC card system.
[0004]
A personal identification system using a contactless IC card does not require the insertion of a card into a card reader when writing and reading card data, unlike a magnetic stripe card, and is excellent in convenience. It is increasingly used as a personal identification medium used in systems. In particular, in a system in which a non-contact card is attached to a chest or the like as a name tag or identification card, the electric lock of the door is unlocked and the door is opened only by approaching the R / W device installed in front of the door. The point that can be done is evaluated.
[0005]
For example, there is an access control system shown in (Patent Document 1), but an antenna unit of an R / W device used in such an access control system is generally exposed or provided on a wall near an entrance door of an office. It can be embedded and mounted on the wall. However, there are many cases where there are electric wires used for other devices, reinforcing bars for reinforcing concrete, etc. around such a mounting place.
[0006]
As described above, despite the fact that the surrounding conditions when the antenna unit of the R / W device is actually installed vary widely, the antenna unit of the conventional R / W device is in a free space. In most cases, when the installation environment changes, the reading performance of the non-contact IC card data is greatly reduced.
[0007]
Therefore, generally, when the R / W device is actually installed, resonance frequency adjustment and impedance adjustment of the antenna unit of the R / W device are individually performed in accordance with each installation location, and appropriate communication is performed. Although the distance is secured, this is a very laborious operation, and is a major problem in installing the R / W device.
[0008]
Therefore, by adding a shield plate described in Patent Literature 2 or Patent Literature 3, the effect of the installation environment behind the antenna unit of the R / W device is reduced, and the antenna resonance frequency is adjusted at the antenna installation location. And methods for adjusting the communication distance have been devised.
[0009]
Furthermore, as another method for reducing the influence of the installation environment of the antenna unit of the R / W device, a method of adding a magnetic substance such as ferrite to the back surface of the antenna described in Patent Document 4 has been devised.
[0010]
Further, a method of adjusting a transmission power and securing an appropriate communication distance even when the resonance frequency and impedance of the antenna unit of the R / W device change has been devised by a method disclosed in (Patent Document 5). I have.
[0011]
[Patent Document 1]
JP-A-8-109764
[Patent Document 2]
JP-A-8-263609
[Patent Document 3]
JP 2001-44747 A
[Patent Document 4]
JP-A-2002-298095
[Patent Document 5]
JP-A-2000-353222
[0012]
[Problems to be solved by the invention]
However, the conventional method is effective for a close contact type (transmission output of 10 mW) where the communication distance between the non-contact IC card and the R / W is about several mm or a close type (transmission output of 1 W) where the communication distance is about 10 cm. In the proximity type (transmission output 4 W) revised in 2002, there is a problem that a problem that cannot be dealt with by the conventional method occurs due to a large transmission power.
[0013]
In the proximity type, since the transmission output is large, heat generation in the transmission unit of the R / W unit is an important issue. As means for reducing heat generation, impedance matching between the antenna of the R / W unit and the transmitting unit is ensured, the quality factor of the antenna is increased, the antenna efficiency is increased, and the power efficiency of the power amplifier of the transmitting unit is increased. However, if any one of these methods has poor characteristics, the overall power efficiency will be low and a problem of heat generation will occur. In particular, if the resonance frequency of the antenna or the impedance of the antenna changes due to the installation environment of the antenna and impedance matching with the transmission unit of the R / W unit cannot be achieved, not only the problem of reduction in the communication distance but also the R / W transmission unit However, there is a problem that an excessive current flows through the R / W transmission unit, causing a serious problem of overheating and destruction of the R / W transmission unit.
[0014]
As a means of the conventional method, a shield plate is added to the R / W antenna unit. However, in the proximity type, since the communication distance is about 50 cm on the front and back sides of the antenna of the R / W device, the communication distance between the R / W antenna unit and the shield is small. If the distance between the plates is not sufficient, the magnetic flux is cut off by the shielding plate, and the communication distance is reduced. If a shield plate is attached so that the communication distance does not decrease, the antenna part of the R / W device becomes structurally thick, and the shield plate cannot be said to be an appropriate means for a remote type.
[0015]
As another means of the conventional method, there is addition of ferrite. However, in the proximity type, the communication distance is not only about 50 cm on the front and back of the antenna of the R / W device, but also at the same time, the antenna portion of the R / W device. The communication range in the horizontal direction is wide, and the communication range is four times or more the antenna area. Therefore, an extremely wide ferrite is required to completely eliminate the influence of the rear surface of the antenna unit of the R / W device. In the case of ferrite having an area approximately equal to the area of the antenna unit of the R / W device, the resonance frequency and the antenna impedance of the antenna unit of the R / W device change due to the influence of the metal on the back surface of the antenna unit of the R / W device. As a result, there has been a problem that an excessive current flows to the transmission unit of the R / W device, which leads to abnormal heat generation and destruction of the transmission unit of the R / W device.
[0016]
Further, even if the resonance frequency and impedance of the antenna unit of the R / W device change, the transmission power is adjusted to secure an appropriate communication distance. In the case of the W device, if the impedance matching between the transmitting unit of the R / W device and the antenna unit of the R / W device is not properly taken, an excessive current flows to the transmitting unit of the R / W device, and the There was a problem that this would lead to abnormal heat generation and destruction of the transmission unit.
[0017]
Therefore, the present invention solves the above-mentioned problems in the conventional technology, and adjusts the antenna impedance and / or the R / W transmission power optimally and automatically. It is intended to provide an adjustment method.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a non-contact IC card read / write device for performing data communication and power supply using electromagnetic waves, wherein the device automatically adjusts the resonance frequency and antenna impedance of an antenna. is there.
[0019]
According to the present invention, a detecting means for detecting a current flowing in a transmitting unit of a R / W device, or detecting a traveling wave or a reflected wave between the R / W transmitting unit and the R / W antenna unit, Means for adjusting the circuit constants of the antenna resonance matching circuit and automatically adjusting the impedance of the antenna and the antenna resonance frequency, thereby achieving impedance matching between the R / W transmitting section and the R / W antenna section at a desired frequency. , An excessive current flows in the R / W transmission unit, which can prevent the R / W transmission unit from abnormally generating heat and reducing the communication distance. / W device is obtained.
[0020]
Further, the present invention detects the transmission power level between the R / W transmission unit and the R / W antenna unit after adjusting the impedance matching and the antenna resonance frequency of the R / W transmission unit and the R / W antenna unit by the means of the invention. R / W device that can secure an appropriate communication distance even in various installation locations by having a detection unit that performs the detection and a unit that adjusts the transmission power of the R / W transmission unit according to the detected level. Is obtained.
[0021]
Further, the present invention has a detecting means for detecting a traveling wave and / or a reflected wave of the R / W transmitting section and the R / W antenna section by the invention means, and the circuit constant of the antenna resonance matching circuit according to the detected level. Has a means for automatically adjusting the impedance of the antenna and the antenna resonance frequency, thereby adjusting the impedance matching and the antenna resonance frequency of the R / W transmitting section and the R / W antenna section, and causing the R / W transmitting section to be excessively large. A large amount of current can flow to prevent the R / W transmission unit from abnormally generating heat and reducing the communication distance, and an R / W device with optimal power efficiency can be obtained even at various installation locations.
[0022]
Further, the present invention has a detecting means for detecting a traveling wave and / or a reflected wave of the R / W transmitting section and the R / W antenna section by the invention means, and the circuit constant of the antenna resonance matching circuit according to the detected level. By adjusting the impedance and the antenna resonance frequency of the R / W transmitter and the R / W antenna by automatically adjusting the impedance of the antenna, and detecting the transmission power level by the detector. By automatically adjusting the transmission power of the R / W unit according to the detected level, an excessive current flows in the R / W transmission unit, causing the R / W transmission unit to generate abnormal heat or a communication distance. Can be prevented, and an R / W device with appropriate power efficiency and an optimum communication distance can be obtained even at various installation locations.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0024]
Here, FIGS. 1 to 11 are block diagrams of R / W devices according to Embodiments 1 to 11 of the present invention, respectively.
[0025]
1 to 11, reference numeral 1 denotes an oscillator, and reference numeral 2 denotes a power amplifier (hereinafter abbreviated as PA). Reference numeral 3 denotes a current detection circuit, 4 denotes a control circuit, 5 denotes an antenna adjustment circuit, 6 denotes an antenna, 7 denotes a transmission unit of the R / W device, 8 denotes an antenna unit of the R / W device, and 9 denotes an R / W device. / W device receiving unit. Reference numeral 10 denotes an R / W device.
[0026]
(Embodiment 1)
In FIG. 1, a carrier generated by an oscillator 1 is amplified to a required power by a power amplifier 2 (PA 2), supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and transmits the magnetic flux 11 to the contactless IC card 12. Power and transmission data are provided. The transmitter 7 is provided with a current detection circuit 3 for the PA 2, controls the circuit constant of the antenna adjustment circuit 5 according to the current flowing to the PA 2, and controls the current flowing to the PA 2 to an optimum value, thereby obtaining an R / W device. The resonance frequency and impedance of the R / W antenna unit 8 are adjusted in accordance with the installation environment of the antenna unit 8 of the R / W device, and the transmission unit 7 of the R / W device and the antenna unit 8 of the R / W device at a desired frequency are adjusted. The impedance is matched so that the communication distance can be secured with an optimum current value automatically without individually adjusting the antenna of the R / W device for each installation environment.
[0027]
(Embodiment 2)
In FIG. 2, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2, supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. The transmitter 7 is provided with the current detector 3 of the PA 2, and a digital signal corresponding to the current value is input to the microcomputer 13. The microcomputer 13 controls the antenna adjustment circuit 5 in accordance with the value of the current flowing in the PA 2, and controls the current flowing in the PA 2 to an optimum value, thereby controlling the R / W device in accordance with the installation environment of the antenna unit 8 of the R / W device. The resonance frequency and impedance of the W antenna unit are adjusted, the impedance of the transmitting unit 7 of the R / W device and the antenna unit 8 of the R / W device are matched at a desired frequency, and the antenna of the R / W device 10 is installed. It is possible to automatically secure the communication distance with the optimum current value without adjusting individually for each environment.
[0028]
(Embodiment 3)
In FIG. 3, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2, supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. The transmitting unit 7 is provided with a traveling wave / reflected wave detection circuit 14 between the transmitting unit 7 and the antenna unit 8, and in accordance with the detected signal, the control circuit 4 makes the reflected wave minimum at the desired frequency and the traveling wave The antenna adjustment circuit 5 is adjusted so as to be the maximum. By adjusting in this manner, impedance matching between the transmission unit 7 of the R / W device and the antenna unit 8 of the R / W device can be achieved. An excessive current is prevented from flowing, and the communication distance can be secured with an optimum current without adjusting the antenna of the R / W device individually for each installation environment.
[0029]
(Embodiment 4)
In FIG. 4, the carrier generated by the oscillator 1 is amplified to the required power by the PA 2, supplied to the antenna 6 via the antenna adjustment circuit 5, generates a magnetic flux 11, and the power and the transmission data are transmitted to the non-contact IC card 12. Supplied. The transmitting unit 7 is provided with a traveling wave / reflected wave detecting circuit 14 between the transmitting unit 7 and the antenna unit 8, and the detected signal is input to the microcomputer 13. The microcomputer 13 adjusts and controls the antenna adjustment circuit 5 by the control circuit 4 in accordance with the detected signal so that the reflected wave is minimum and the traveling wave is maximum at a desired frequency. By adjusting in this manner, impedance matching between the transmission unit 7 of the R / W device and the antenna unit 8 of the R / W device can be achieved. An excessive current is prevented from flowing, and the communication distance can be secured with an optimum current without adjusting the antenna of the R / W device individually for each installation environment.
[0030]
(Embodiment 5)
In FIG. 5, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2, supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. The transmitting unit 7 includes a traveling wave / reflected wave detecting circuit 14 between the transmitting unit 7 and the antenna unit 8, and the detected signal is input to the PA control circuit 4. The PA control circuit 4 adjusts the output impedance of the PA 2 according to the detected signal, and can match the impedance with the antenna unit 8 or control the transmission output. By adjusting in this manner, impedance matching between the transmission unit 7 of the R / W device and the antenna unit 8 of the R / W device can be performed at a desired frequency, and the transmission output can be controlled. Depending on the installation environment of the antenna unit 8, it is possible to prevent an excessive current from flowing through the transmission unit 7, and to optimize the current and transmission of the transmission unit 7 without adjusting the antenna of the R / W device individually for each installation environment. The output allows the communication distance to be secured.
[0031]
(Embodiment 6)
In FIG. 6, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2, supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. The transmitting unit 7 is provided with a traveling wave / reflected wave detecting circuit 14 between the transmitting unit 7 and the antenna unit 8, and the detected signal is input to the microcomputer 13. The microcomputer 13 controls the control circuit 4 in accordance with the input signal, adjusts the output impedance of the PA 2, adjusts the impedance with the antenna unit 8, and controls the transmission output. By adjusting in this manner, impedance matching between the transmission unit 7 of the R / W device and the antenna unit 8 of the R / W device can be performed at a desired frequency, and the transmission output can be controlled. According to the installation environment of the antenna unit 8, excessive current is prevented from flowing to the transmission unit 7, and the optimum current and transmission of the transmission unit 9 can be controlled without individually adjusting the antenna of the R / W device for each installation environment. The output allows the communication distance to be secured.
[0032]
(Embodiment 7)
In FIG. 7, the carrier generated by the oscillator 1 is amplified to the required power by the PA 2, supplied to the antenna 6 via the antenna adjustment circuit 5, generates the magnetic flux 11, and the power and the transmission data are transmitted to the non-contact IC card 12. Supplied. The transmitting section 7 is provided with a traveling wave / reflected wave detecting circuit 14 between the transmitting section 7 and the antenna section 8, and the detected signal is input to the control circuit 4. The control circuit 4 controls the duty of the carrier signal generated from the oscillator 1 which is a carrier transmitting circuit. When PA2 is a switching amplifier for class E operation, for example, the output power can be controlled by controlling the duty of the signal input to the amplifier. In the example of the seventh embodiment, the control circuit 4 controls the duty adjustment circuit 15 according to the level detected by the traveling wave / reflected wave detection circuit 14 to adjust the transmission power of the PA2 of the class E operation amplifier. Therefore, if an excessive current flows through the transmission unit 7 depending on the installation environment of the antenna unit 8 of the R / W device, the transmission power is controlled to automatically control the overcurrent, heat generation, and destruction of the transmission unit 7. So that you can prevent it.
[0033]
(Embodiment 8)
In FIG. 8, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2 and supplied to an antenna 6 via an antenna adjustment circuit 5 to generate a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. The transmitting unit 7 is provided with a traveling wave / reflected wave detecting circuit 14 between the transmitting unit 7 and the antenna unit 8, and the detected signal is input to the microcomputer 13. The microcomputer 13 controls the control circuit 4 via the control circuit 4 according to the input signal. The control circuit 4 controls the duty of the carrier signal of the oscillator 1. When the PA2 is, for example, a switching amplifier of class E operation or the like, the output power can be controlled by controlling the duty of the signal input to the amplifier. In the example of the seventh embodiment, the control circuit 4 controls the duty adjustment circuit 15 in accordance with the level detected by the traveling wave / reflected wave detection circuit 14 to adjust the transmission power of the class E operation amplifier PA2. If an excessive current seems to flow through the transmitting unit 7 depending on the installation environment of the antenna unit 8 of the R / W device, the transmitting power is controlled to automatically prevent the overcurrent, heat generation, and destruction of the transmitting unit 7. To prevent it.
[0034]
(Embodiment 9)
FIG. 9 shows a combination of the second embodiment and the eighth embodiment. In FIG. 9, the carrier generated by the oscillator 1 is amplified to the required power by the PA 2, supplied to the antenna 6 via the antenna adjustment circuit 5, generates the magnetic flux 11, and the power and the transmission data are transmitted to the non-contact IC card 12. Supplied. The power detection circuit 17 is provided in the transmission unit 7, and the detected signal is input to the microcomputer 13. Further, a current detection circuit unit 3 for detecting the current of PA2 of the transmission unit 7 is provided, and the detection level is input to the microcomputer 13. The microcomputer 13 controls the antenna adjustment circuit 5 in accordance with the current flowing in the PA 2, and controls the current flowing in the PA 2 to an optimum value, thereby controlling the R / W according to the installation environment of the antenna unit 8 of the R / W device. The resonance frequency of the antenna unit is adjusted, the impedance is adjusted, and the transmission unit 7 of the R / W device and the antenna unit 8 of the R / W device are impedance-matched. Next, the microcomputer 13 controls the duty adjustment circuit 15 according to the detection level from the power detection circuit 17 input to the microcomputer 13, and adjusts the transmission output of the PA2 to a predetermined level for the first time. After automatically adjusting the impedance of the transmitting unit 7 of the R / W device and the antenna unit 8 of the R / W device in this way, by automatically adjusting the transmission power, the R / W device can be set for each installation environment. Therefore, it is possible to secure an optimum communication efficiency with an optimum power efficiency, an optimum power, and an optimum communication distance without making adjustments individually.
[0035]
(Embodiment 10)
In FIG. 10, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2, supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. In the AM modulation type R / W device, AM modulation is often performed by changing the power supply voltage of PA2. In this case, the potential difference between both ends of a resistor in the AM modulator flows to PA2. The current can be detected. In the example of the tenth embodiment shown in FIG. 10, the power detection circuit 17 performs AM modulation and current detection. The detected current value is input to the microcomputer 13. The microcomputer controls the antenna adjustment circuit 5 in accordance with the current flowing in the PA2 and controls the current flowing in the PA2 to an optimum value, so that the microcomputer operates at a desired frequency in accordance with the installation environment of the antenna unit 8 of the R / W device. The resonance frequency and impedance of the R / W antenna unit are adjusted, the impedance of the transmitting unit 7 of the R / W device and the antenna unit 8 of the R / W device are matched, and the antenna of the R / W device is installed for each installation environment. Even without individual adjustment, the communication distance is automatically secured with the optimum current.
[0036]
(Embodiment 11)
In FIG. 11, a carrier generated by an oscillator 1 is amplified to a required power by a PA 2, supplied to an antenna 6 via an antenna adjustment circuit 5, generates a magnetic flux 11, and the power and transmission data are transmitted to a non-contact IC card 12. Supplied. The transmitting unit 7 has a current detection 3 of the PA 2, which is input to the microcomputer 13. The current detection 3 resistor is inserted in series between PA2 and the power supply. By reading the potential difference between both ends of the resistor, the current flowing through PA2 can be detected. The microcomputer controls the antenna adjustment circuit 5 in accordance with the current flowing in the PA2 and controls the current flowing in the PA2 to an optimum value, so that the microcomputer operates at a desired frequency in accordance with the installation environment of the antenna unit 8 of the R / W device. The resonance frequency and impedance of the R / W antenna unit are adjusted, the impedance of the transmitting unit 7 of the R / W device and the antenna unit 8 of the R / W device are matched, and the antenna of the R / W device is installed for each installation environment. Even without individual adjustment, the communication distance is automatically secured with the optimum current.
[0037]
(Embodiment 12)
The first to eleventh embodiments described above are operated only when the antenna of the R / W device is installed, so that the antenna of the R / W device and the R / W device can be changed depending on the installation environment of the R / W device. Since the transmission output is automatically adjusted, there is no need to adjust the antenna of the R / W device or adjust the transmission output of the R / W device for each installation environment, which was performed when the antenna of the R / W device was attached as in the past. , Can be easily installed. During normal operation after installation, these automatic adjustment functions are not operated, but are operated as a normal non-contact IC card R / W device.
[0038]
(Embodiment 13)
The first to eleventh embodiments described above are operated when the antenna of the R / W device is installed, so that the transmission of the antenna of the R / W device and the transmission of the R / W device according to the installation environment of the R / W device. Because the output is automatically adjusted, without adjusting the antenna of the R / W device or adjusting the transmission output of the R / W device for each installation environment, which was performed when the antenna of the R / W device was attached as in the past, It can be easily installed. In addition, these automatic adjustment functions are operated during normal operation after installation.
[0039]
In a general R / W device without these automatic adjustment functions, when the antenna installation environment changes due to external personnel or the like, the impedance and the resonance frequency of the antenna change, the power efficiency drops, and a large current flows in the transmission unit. Or the communication distance decreases. However, if these automatic adjustment functions are constantly functioning, the antenna impedance and resonance frequency are adjusted automatically even if the antenna installation environment changes due to external personnel, and the transmission power adjustment is also performed automatically. Therefore, the power efficiency is reduced, a large current flows in the transmission unit, and the communication distance can be always secured with the optimum power efficiency without reducing the communication distance.
[0040]
As described above, the first to thirteenth embodiments of the present invention have been described. As described above, the carrier wave from the oscillator 1 is amplified by the power amplifier 2 which is a power amplifier. It is preferable to use an amplifier. By using a class E amplifier, high-efficiency operation can be realized. Therefore, heat generation can be suppressed even when the transmission output is increased.
[0041]
Note that the definition of the non-contact IC card in the present invention is not limited to a so-called card, but is a wireless communication medium capable of performing communication with the R / W device in a non-contact manner. Therefore, it includes what is called an IC tag, an ID tag, and an identification label depending on the use.
[0042]
【The invention's effect】
As described above, according to the present invention, the detection unit detects the current flowing in the transmission unit of the R / W device, or detects the traveling wave and the reflected wave between the R / W transmission unit and the R / W antenna unit. By automatically adjusting the circuit constant of the antenna resonance circuit according to the level and automatically adjusting the impedance and resonance frequency of the antenna, the impedance matching between the R / W transmission unit and the R / W antenna unit is obtained. The transmission power level is detected by the transmission power detection means, and the transmission power of the R / W section is automatically adjusted according to the detected level. It is possible to prevent a large current from flowing, the R / W transmitter to generate abnormal heat, and the communication distance to be reduced. Automatically correct power Rate and optimal R / W device that ensures the communication distance can be obtained.
[0043]
Therefore, according to the present invention, it is possible to provide a non-contact IC card read / write device capable of automatically and automatically adjusting the impedance of an antenna and / or the R / W transmission power, and a method of adjusting the same.
[Brief description of the drawings]
FIG. 1 is a block diagram of an R / W device according to a first embodiment of the present invention.
FIG. 2 is a block diagram of an R / W device according to a second embodiment of the present invention.
FIG. 3 is a block diagram of an R / W device according to a third embodiment of the present invention.
FIG. 4 is a block diagram of an R / W device according to a fourth embodiment of the present invention.
FIG. 5 is a block diagram of an R / W device according to a fifth embodiment of the present invention.
FIG. 6 is a block diagram of an R / W device according to a sixth embodiment of the present invention.
FIG. 7 is a block diagram of an R / W device according to a seventh embodiment of the present invention.
FIG. 8 is a block diagram of an R / W device according to an eighth embodiment of the present invention.
FIG. 9 is a block diagram of an R / W device according to a ninth embodiment of the present invention.
FIG. 10 is a block diagram of an R / W device according to a tenth embodiment of the present invention.
FIG. 11 is a block diagram of an R / W device according to an eleventh embodiment of the present invention.
FIG. 12 is an explanatory diagram of a non-contact IC card system.
[Explanation of symbols]
1 oscillator
2 Power amplifier
3 Current detection circuit
4 Control circuit
5 Antenna adjustment circuit
6 Antenna
7 Transmission section
8 Antenna part
9 Receiver
10 R / W device
11 Magnetic flux
12 Non-contact IC card
13 Microcomputer
14 Traveling wave and reflected wave detection circuit
15 Duty adjustment circuit
16 Control circuit
17 Power detection circuit
21 Non-contact IC card
22 IC chip
23 Antenna
24 Antenna part
25 Body
26 R / W device
27 PC

Claims

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A microcomputer for detecting a resonance frequency and an antenna impedance of the antenna by changing a circuit constant of an antenna resonance circuit of the antenna unit according to a current level obtained by the detection circuit; Non-contact IC card read / write device, which automatically adjusts without intervening.

A non-contact IC card read / write device that includes a transmission unit and an antenna unit and performs data communication and power supply by using electromagnetic waves,
A microcomputer for detecting a resonance frequency and an antenna impedance of the antenna by changing a circuit constant of an antenna resonance circuit of the antenna unit according to a current level obtained by the detection circuit; A non-contact IC card read / write device, wherein the automatic adjustment is performed by intervening.

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A detecting circuit that detects a traveling wave or a reflected wave of a transmission signal between the transmitting unit and the antenna unit, and according to a level of the traveling wave or the reflected wave obtained by the detecting circuit, an antenna resonance circuit of the antenna unit. A non-contact IC card read / write device characterized by automatically adjusting the resonance frequency and impedance of an antenna by interposing a microcomputer by changing a circuit constant.

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A detecting circuit that detects a traveling wave or a reflected wave of a transmission signal between the transmitting unit and the antenna unit, and according to a level of the traveling wave or the reflected wave obtained by the detecting circuit, an antenna resonance circuit of the antenna unit. A non-contact IC card read / write device characterized by automatically adjusting the resonance frequency and impedance of an antenna through a microcomputer by changing a circuit constant.

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A detection circuit that detects a traveling wave or a reflected wave of a transmission signal between the transmission unit and the antenna unit, and adjusts an output impedance of the transmission unit according to a level of the traveling wave or the reflected wave obtained by the detection circuit. A non-contact IC card read / write device characterized in that a predetermined transmission power level is automatically adjusted without a microcomputer by controlling a voltage supplied to a power amplifier of the transmission unit.

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A detection circuit that detects a traveling wave or a reflected wave of a transmission signal between the transmission unit and the antenna unit, and adjusts an output impedance of the transmission unit according to a level of the traveling wave or the reflected wave obtained by the detection circuit. A non-contact IC card read / write device, which automatically adjusts a predetermined transmission power level via a microcomputer by controlling a voltage supplied to a power amplifier of the transmission unit.

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A detecting circuit that detects a traveling wave or a reflected wave of the transmission signal between the transmitting unit and the antenna unit, and controls a duty of the transmitting carrier according to a level of the traveling wave or the reflected wave obtained by the detection circuit. A non-contact IC card read / write device for automatically adjusting a predetermined transmission power level without using a microcomputer.

A non-contact IC card read / write device that includes a transmitting unit and an antenna unit and performs data communication and power supply by electromagnetic waves,
A detecting circuit that detects a traveling wave or a reflected wave of the transmission signal between the transmitting unit and the antenna unit, and controls a duty of the transmitting carrier according to a level of the traveling wave or the reflected wave obtained by the detection circuit. A non-contact IC card read / write device automatically adjusting a predetermined transmission power level via a microcomputer.

In the detection circuit for detecting the current of the transmission unit of the read / write device, the potential difference between both ends of the resistor used in the modulation circuit is measured to utilize the current for the current detection of the transmission unit of the read / write device. The read / write device according to claim 1, wherein the read / write device comprises a detection circuit.

In the detection circuit for detecting the current of the transmission unit of the read / write device, the current of the transmission unit of the read / write device is detected by measuring the potential difference between both ends of the resistor inserted in series with the transmission unit. The non-contact IC card read / write device according to any one of claims 1 and 2, wherein:

The combination of at least one of the automatic adjustment functions according to any one of claims 1 to 4 and at least one of the automatic production functions according to any one of claims 5 to 8, A non-contact IC card read / write device, which automatically adjusts a resonance frequency and an impedance to a predetermined transmission power level.

The non-contact IC card read / write device according to any one of claims 1 to 11, wherein the automatic adjustment functions at least when the read / write device is installed.

13. The non-contact IC card read / write device according to claim 12, wherein the automatic adjustment functions even during operation after installation of the read / write device.

A method for adjusting an antenna resonance frequency and an antenna impedance of a read / write device of a non-contact IC card for performing data communication and power supply by using an electromagnetic wave, wherein the detection circuit detects a current of a transmission unit of the read / write device, and the detection circuit. By changing the circuit constant of the antenna resonance circuit of the antenna part of the read / write device according to the current level obtained by the circuit, the resonance frequency and antenna impedance of the antenna are automatically adjusted without the intervention of a microcomputer. Non-contact IC card read / write device adjustment method.

A method for adjusting an antenna resonance frequency and an antenna impedance of a read / write device of a non-contact IC card for performing data communication and power supply by using an electromagnetic wave, wherein the detection circuit detects a current of a transmission unit of the read / write device, and the detection circuit. By changing the circuit constant of the antenna resonance circuit of the antenna part of the read / write device according to the current level obtained by the circuit, the resonance frequency and antenna impedance of the antenna are automatically adjusted via a microcomputer. For adjusting a non-contact IC card read / write device.

An antenna resonance frequency and antenna impedance adjustment method of a read / write device of a non-contact IC card that performs data communication and power supply by using an electromagnetic wave, wherein a transmission between a transmission unit of the read / write device and an antenna unit of the read / write device is performed. By changing the circuit constant of the antenna resonance circuit of the antenna unit of the read / write device according to the level of the traveling wave or the reflected wave obtained by the detection circuit for detecting the traveling wave or the reflected wave of the signal, A method for adjusting a non-contact IC card read / write device, wherein the resonance frequency and impedance of an antenna are automatically adjusted without the intervention of a microcomputer.

An antenna resonance frequency and antenna impedance adjustment method of a read / write device of a non-contact IC card that performs data communication and power supply by using an electromagnetic wave, wherein a transmission between a transmission unit of the read / write device and an antenna unit of the read / write device is performed. By changing the circuit constant of the antenna resonance circuit of the antenna unit of the read / write device according to the level of the traveling wave or the reflected wave obtained by the detection circuit for detecting the traveling wave or the reflected wave of the signal, A method for adjusting a non-contact IC card read / write device, wherein the resonance frequency and impedance of an antenna are automatically adjusted via a microcomputer.

A method for adjusting the output impedance and transmission power of a transmission unit of a read / write device of a non-contact IC card that performs data communication and power supply using electromagnetic waves, comprising: a transmission unit of the read / write device and an antenna unit of the read / write device. A detection circuit that detects the traveling wave or reflected wave of the transmission signal between the two, and adjusts the output impedance of the transmission unit according to the level of the traveling wave or reflected wave obtained by the detection circuit, or supplies it to the transmission unit power amplifier A method for adjusting a non-contact IC card read / write device, wherein a predetermined transmission power level is automatically adjusted without controlling a microcomputer by controlling a voltage to be applied.

A method for adjusting the output impedance and transmission power of a transmission unit of a read / write device of a non-contact IC card that performs data communication and power supply using electromagnetic waves, comprising: a transmission unit of the read / write device and an antenna unit of the read / write device. A detection circuit that detects the traveling wave or reflected wave of the transmission signal between the two, and adjusts the output impedance of the transmission unit according to the level of the traveling wave or reflected wave obtained by the detection circuit, or supplies it to the transmission unit power amplifier A method for adjusting a non-contact IC card read / write device, characterized by automatically adjusting a predetermined transmission power level through a microcomputer by controlling a voltage to be applied.

A method for adjusting a transmission power of a transmission unit of a read / write device of a non-contact IC card for performing data communication and power supply by using an electromagnetic wave, wherein transmission between the transmission unit of the read / write device and an antenna unit of the read / write device is performed. A detection circuit that detects a traveling wave or a reflected wave of a signal, and a microcomputer is interposed at a predetermined transmission power level by controlling the duty of the transmission carrier according to the level of the traveling wave or the reflection wave obtained by the detection circuit. A method for adjusting a non-contact IC card read / write device, characterized in that the adjustment is performed automatically without using a device.

A method for adjusting a transmission power of a transmission unit of a read / write device of a non-contact IC card for performing data communication and power supply by using an electromagnetic wave, wherein transmission between the transmission unit of the read / write device and an antenna unit of the read / write device is performed. A detection circuit that detects a traveling wave or a reflected wave of a signal, and by controlling the duty of the transmission carrier according to the level of the traveling wave or the reflection wave obtained by the detection circuit, a microcomputer is interposed at a predetermined transmission power level. A method for adjusting a non-contact IC card read / write device, wherein the adjustment is performed automatically.

18. A method for adjusting an antenna impedance of a read / write device of a non-contact IC card which performs data communication and power supply using electromagnetic waves, and a method of adjusting a transmission power of a transmission unit of the read / write device. A combination of at least one of the methods according to any one of the claims and at least one of the methods according to any one of the claims 18 to 21 automatically adjusts a resonance frequency and an impedance of the antenna, and performs predetermined transmission. A method for adjusting a non-contact IC card read / write device, which automatically adjusts to a power level.

In the detection circuit for detecting the current of the transmission unit of the read / write device, the potential difference between both ends of the resistor used in the modulation circuit is measured to utilize the current for the current detection of the transmission unit of the read / write device. 16. The method for adjusting a non-contact IC card read / write device according to claim 14, wherein a detection circuit is configured.

In the detection circuit for detecting the current of the transmission unit of the read / write device, the current of the transmission unit of the read / write device is detected by measuring the potential difference between both ends of the resistor inserted in series with the transmission unit. The method for adjusting a non-contact IC card read / write device according to any one of claims 14 and 15, wherein:

25. The method for adjusting a non-contact IC card read / write device according to claim 14, wherein the adjustment method functions only when the read / write device is installed.

The adjustment method according to any one of claims 14 to 24, which functions when a read / write device is installed or when the device is operated after installation. How to adjust the device.