本発明は周波数シフト形ＲＦＩＤデバイスに関し、とくにコイル状アンテナの受信時の誘導起電力によりＩＣ回路を駆動するパッシブ型のＲＦＩＤデバイスに関する。 The present invention relates to a frequency shift type RFID device, and more particularly to a passive type RFID device that drives an IC circuit by an induced electromotive force during reception of a coiled antenna.
近年、アンテナ及びＩＣ回路を内蔵した電子タグに対して無線通信により非接触でデータを読み書きするＲＦＩＤ（Radio Frequency Identification；無線周波数識別）通信技術を利用したシステムが生産管理・物流管理・入退室管理等の分野で普及してきており、土木・建設分野においても、従来のケーブル等を用いた有線通信に代えて無線通信可能な電子タグ（以下、ＲＦＩＤデバイスということがある）を活用して作業の効率化・自動化を図る技術の開発が進められている。例えば特許文献１及び２は、構造物の維持管理や防災管理を目的として、歪センサ・圧力センサ等と組み合わせたＲＦＩＤデバイスを構造物に取り付け、そのセンサで検出した構造物の歪・変位・圧力等の力学的変化をＲＦＩＤデバイス経由で無線通信する構造物の監視システム（モニタリングシステム）を提案している。 In recent years, systems using RFID (Radio Frequency Identification) communication technology for reading and writing data wirelessly without contact with electronic tags with built-in antennas and IC circuits have been managed for production management, logistics management, and entrance / exit management. In the civil engineering / construction field, it is possible to use an electronic tag (hereinafter sometimes referred to as an RFID device) capable of wireless communication in place of conventional wired communication using a cable or the like. Development of technology to improve efficiency and automation is underway. For example, in Patent Documents 1 and 2, an RFID device combined with a strain sensor, a pressure sensor, or the like is attached to a structure for the purpose of maintenance and disaster prevention management of the structure, and the strain, displacement, and pressure of the structure detected by the sensor. Have proposed a structure monitoring system (monitoring system) that wirelessly communicates such mechanical changes via an RFID device.
一般にＲＦＩＤデバイスには、電池を搭載したアクティブ型と、電池を内蔵しないパッシブ型とがある。例えば特許文献１は、力学的変化を検出するセンサの消費電力を供給する必要があることから、アクティブ型のＲＦＩＤデバイスを使用している。しかし、土木・建築分野ではＲＦＩＤデバイスによる監視を長期にわたり継続しなければならない場合も多く、電池を交換しなければ使用期間が限定されるアクティブ型よりも、無電力で半永久的に通信機能なパッシブ型のＲＦＩＤデバイスを用いたシステムとすることが望ましい。 In general, RFID devices include an active type in which a battery is mounted and a passive type in which no battery is built. For example, Patent Document 1 uses an active RFID device because it is necessary to supply power consumption of a sensor that detects a mechanical change. However, in civil engineering and construction, there are many cases in which monitoring with RFID devices must be continued for a long period of time. A system using a type of RFID device is desirable.
これに対して特許文献３及び４は、パッシブ型のＲＦＩＤデバイス（電子タグ）を用いて型枠内に打設するコンクリートの充填状況を監視するシステムを提案している。図１０を参照して、特許文献３の開示するコンクリート充填監視システムを本発明の理解に必要な程度において説明する。図示例のＲＦＩＤデバイス（電子タグ）40は、無線信号を送受信する電子タグ本体41と、電子タグ本体41を被覆する止水カバー48と、止水カバー48の一端又は両端を片持はり又は固定はり状に支持する台座49とで構成されている（同図（Ｃ）参照）。図１１に示すように、電子タグ本体41はアンテナ42とＩＣ回路43とを有し、アンテナ42の受信時の電磁誘導又は共振によってＩＣ回路43を駆動するパッシブ型のものである。すなわち、ＩＣ回路43には電源回路44と制御回路45と記憶回路46と送受信回路47とが組み込まれており、アンテナ42が無線読み出し信号Ｒを受信すると、その受信時の電磁誘導又は共振によって電源回路44が駆動され、その電源により制御回路45が記憶回路46に記憶された識別信号Ｓを読み取り、読み取った識別信号Ｓを送受信回路47によりアンテナ42から無線送信する。 On the other hand, Patent Documents 3 and 4 propose a system for monitoring a filling state of concrete placed in a mold using a passive RFID device (electronic tag). With reference to FIG. 10, the concrete filling monitoring system disclosed in Patent Document 3 will be described to the extent necessary for understanding the present invention. The illustrated RFID device (electronic tag) 40 includes an electronic tag main body 41 that transmits and receives radio signals, a water stop cover 48 that covers the electronic tag main body 41, and one end or both ends of the water stop cover 48 cantilevered or fixed. It is comprised with the base 49 supported in a beam shape (refer the figure (C)). As shown in FIG. 11, the electronic tag main body 41 has an antenna 42 and an IC circuit 43, and is a passive type that drives the IC circuit 43 by electromagnetic induction or resonance at the time of reception of the antenna 42. That is, the IC circuit 43 includes a power supply circuit 44, a control circuit 45, a storage circuit 46, and a transmission / reception circuit 47. When the antenna 42 receives the wireless read signal R, the power is supplied by electromagnetic induction or resonance at the time of reception. The circuit 44 is driven, and the control circuit 45 reads the identification signal S stored in the memory circuit 46 by the power supply, and the read identification signal S is wirelessly transmitted from the antenna 42 by the transmission / reception circuit 47.
図１０（Ａ）及び同図（Ｂ）に示すように、上述した複数の電子タグ40を、コンクリート型枠31a〜31hで囲まれた空隙30内（例えば型枠31a〜31hの打設面等の空隙内面30a上又は鉄筋33上）の複数の所定部位Ｐにそれぞれ取り付ける。電子タグ40の止水カバー48はコンクリートＣの圧力によって破壊されるように設計されており、電子タグ本体41の識別信号Ｓの送信機能は止水カバー48で保護されている間は維持されるが（同図（Ｃ）参照）、コンクリートＣの圧力で止水カバー48が破壊されると絶縁が破壊されて失われる（同図（Ｄ）参照）。例えば、台座49上に片持はり又は固定はり状に支持した止水カバー48の強度（曲げ強さ）をコンクリートＣの充填時に型枠31の内面30aに加わる圧力の曲げモーメントによって破壊されるように設計し、コンクリートＣの充填に応じて止水カバー48を破壊して電子タグ本体41の識別信号Ｓの送信機能を停止させる。 As shown in FIGS. 10A and 10B, the plurality of electronic tags 40 described above are placed in the gap 30 surrounded by the concrete molds 31a to 31h (for example, placement surfaces of the molds 31a to 31h, etc.) Are attached to a plurality of predetermined portions P on the gap inner surface 30a or on the reinforcing bar 33). The waterproof cover 48 of the electronic tag 40 is designed to be destroyed by the pressure of the concrete C, and the transmission function of the identification signal S of the electronic tag main body 41 is maintained while it is protected by the waterproof cover 48. However, when the water stop cover 48 is destroyed by the pressure of the concrete C, the insulation is destroyed and lost (see FIG. 4D). For example, the strength (bending strength) of the water-stop cover 48 supported in the form of a cantilever or fixed beam on the pedestal 49 is destroyed by the bending moment of the pressure applied to the inner surface 30a of the mold 31 when the concrete C is filled. The water stop cover 48 is destroyed in accordance with the filling of the concrete C, and the transmission function of the identification signal S of the electronic tag main body 41 is stopped.
型枠31で囲まれた空隙30内にコンクリートＣを打設する際に、型枠31の外側の読み出し装置（リーダ）20によって各電子タグ40の識別信号Ｓを繰り返し読み取り、読み取りの停止した識別信号Ｓを検出する。なお、電子タグ40は数mm〜数十mmの小型のものであり、コンクリートＣ中に埋め込まれても強度的な問題となるおそれは少ない。図１１に示すように読み出し装置20の一例は、読み出し信号Ｒを送信するアンテナ21及び送受信部24と電源25と制御部27とを有するコンピュータであり、その制御部27には、各電子タグ40の取り付け部位Ｐ及び識別信号Ｓを記憶する手段27aと、各電子タグ40の識別信号Ｓを読み取る手段27bと、読み取りの停止した電子タグ40の識別信号Ｓから取り付け部位Ｐを検出する手段27cと、その読み取りの停止した識別信号Ｓ及び取り付け部位Ｐをディスプレイ26に表示する手段29として機能するプログラムが内蔵されている。型枠31の外側の作業員は、読み出し装置20のディスプレイ26に表示された読み取りの停止した電子タグ40の取り付け部位Ｐにより、型枠31内のコンクリートＣの充填状況をリアルタイムで確認することができる。 When the concrete C is placed in the gap 30 surrounded by the mold 31, the identification signal S of each electronic tag 40 is repeatedly read by the reading device (reader) 20 outside the mold 31 and the reading is stopped. A signal S is detected. The electronic tag 40 is a small one of several mm to several tens mm, and even if it is embedded in the concrete C, there is little possibility of causing a strength problem. As shown in FIG. 11, an example of the reading device 20 is a computer having an antenna 21 and a transmission / reception unit 24 for transmitting a read signal R, a power source 25, and a control unit 27. The control unit 27 includes each electronic tag 40. Means 27a for storing the attachment part P and the identification signal S, means 27b for reading the identification signal S of each electronic tag 40, means 27c for detecting the attachment part P from the identification signal S of the electronic tag 40 whose reading has been stopped, A program that functions as means 29 for displaying the identification signal S and the attachment site P for which reading has stopped on the display 26 is incorporated. An operator outside the form 31 can check the filling state of the concrete C in the form 31 in real time by the attachment part P of the electronic tag 40 stopped reading displayed on the display 26 of the reading device 20. it can.
図１０に示すパッシブ型のＲＦＩＤデバイス（電子タグ）40は、コンクリートＣの圧力により止水カバー48を破壊して送信機能を停止させるものであるが、例えば止水カバー48の強度（曲げ強さ）が異なる複数の電子タグ40を用いることで圧力変化を検出するＲＦＩＤデバイスへと改良することも期待できる。しかし、特許文献３及び４（とくに特許文献４の段落0023）は、例えば400MHz〜GHzレベルの高周波数電磁波の使用をも想定しており、高周波数電磁波は地中又は水中のように導電率の高い媒体中で大きく減衰するので、読み出し装置20との間にそのような導電率の高い媒質が存在すると通信ができなくなるおそれがある。 The passive RFID device (electronic tag) 40 shown in FIG. 10 is one that breaks the water stop cover 48 by the pressure of the concrete C and stops the transmission function. For example, the strength (bending strength) of the water stop cover 48 The use of a plurality of electronic tags 40 with different ()) can be expected to be improved to an RFID device that detects a pressure change. However, Patent Documents 3 and 4 (particularly, paragraph 0023 of Patent Document 4) also assume the use of high-frequency electromagnetic waves of, for example, 400 MHz to GHz level, and the high-frequency electromagnetic waves have conductivity as in the ground or water. Since it is greatly attenuated in a high medium, there is a possibility that communication cannot be performed if such a medium with high conductivity exists between the reading apparatus 20 and the medium.
例えば図１２に示すように地山Ｅに掘削したトンネルにコンクリート覆工を施す場合は、掘削した地山Ｅとトンネル内側に組み立てたセントル（覆工型枠）32との間に覆工コンクリートＣを充填する。このコンクリートＣの充填状況を図１０のシステムで監視する場合は、セントル32の打設面32aに電磁タグ40aを取り付けると共に地山Ｅの表面にも電磁タグ40bを取り付け、セントル32の内側の読み出し装置20により電磁タグ40a、40bからの無線識別信号Ｓの読み取り停止をそれぞれ検出する必要がある。この地山Ｅの表面の電磁タグ40bと読み出し装置20とは、コンクリートＣの打設時に水分を含むコンクリートＣを介して通信しなければならないので、高周波数の電磁波ではコンクリートＣ中で電磁波が減衰するので通信困難となりうる。 For example, as shown in FIG. 12, when a concrete lining is applied to a tunnel excavated in the natural ground E, the lining concrete C is placed between the excavated natural ground E and a centle (covering formwork) 32 assembled inside the tunnel. Fill. When monitoring the filling state of the concrete C with the system of FIG. 10, the electromagnetic tag 40a is attached to the casting surface 32a of the center 32 and the electromagnetic tag 40b is also attached to the surface of the natural ground E to read out the inside of the center 32. It is necessary to detect the reading stop of the radio identification signal S from the electromagnetic tags 40a and 40b by the device 20, respectively. Since the electromagnetic tag 40b on the surface of the natural ground E and the reading device 20 must communicate with each other through the concrete C containing moisture when the concrete C is placed, the electromagnetic waves are attenuated in the concrete C with high frequency electromagnetic waves. Communication can be difficult.
上述した高周波数電磁波に比して例えばkHz〜MHzレベルの低周波数電磁波は、導電率の高い媒質中でも小さな減衰で伝播することが知られている。図１２のような覆工コンクリートＣの充填状況を監視するには、導電率の高い媒質中でも減衰しにくい低周波数電磁波で通信するコイル（ソレノイドコイル）状アンテナを用いたＲＦＩＤデバイスを用いることが望ましい。土木・建築分野では、地中又は水中にＲＦＩＤデバイスを配置しなければならない場合も多く、低周波数で通信するコイル状アンテナを用いて歪・変位・圧力等の力学的変化を検出できるＲＦＩＤデバイスの開発が望まれている。 It is known that a low-frequency electromagnetic wave of, for example, a kHz to MHz level, as compared with the above-described high-frequency electromagnetic wave, propagates with a small attenuation even in a medium with high conductivity. In order to monitor the filling state of the lining concrete C as shown in FIG. 12, it is desirable to use an RFID device using a coil (solenoid coil) antenna that communicates with a low-frequency electromagnetic wave that is difficult to attenuate even in a medium with high conductivity. . In the civil engineering / architecture field, RFID devices often have to be placed in the ground or underwater, and RFID devices that can detect mechanical changes such as strain, displacement, and pressure using a coiled antenna that communicates at low frequencies. Development is desired.
そこで本発明の目的は、コイル状アンテナを用いて力学的変化を検出できるパッシブ型のＲＦＩＤデバイスを提供することにある。 Accordingly, an object of the present invention is to provide a passive RFID device that can detect a mechanical change using a coiled antenna.
本発明者は、コイル状アンテナの近傍に磁性体（又は導電体）を配し、その磁性体を外力によりコイルに接近又はコイルから離隔させてアンテナの通信状態を変化させることに着目した。従来から、例えば磁芯となる磁性材にソレノイドコイルを巻き付けてアンテナとしたＲＦＩＤデバイスが知られているが（特許文献５及び６参照）、ソレノイドコイルと磁性材との間隔を変化させるＲＦＩＤデバイスは提案されていない。コイル状アンテナと磁性材又は導電体との間隔を外力により変化させて通信状態を変化させれば、電力を消費するセンサ等を用いることなく歪・変位・圧力等の力学的変化を検出できるＲＦＩＤデバイスとすることが期待できる。本発明は、この着想に基づく研究開発の結果、完成に至ったものである。 The present inventor paid attention to arranging a magnetic body (or a conductor) in the vicinity of the coiled antenna and changing the communication state of the antenna by moving the magnetic body close to or away from the coil by an external force. Conventionally, for example, an RFID device is known in which a solenoid coil is wound around a magnetic material serving as a magnetic core (see Patent Documents 5 and 6), but an RFID device that changes the interval between the solenoid coil and the magnetic material is known. Not proposed. RFID that can detect mechanical changes such as strain, displacement, pressure, etc. without using a power consuming sensor, etc., if the communication state is changed by changing the distance between the coiled antenna and the magnetic material or conductor by external force It can be expected to be a device. The present invention has been completed as a result of research and development based on this idea.
図１の実施例を参照するに、本発明による周波数シフト形ＲＦＩＤデバイスは、コイル状アンテナ２と磁性体３又は導電体４とを外力により間隔Ｗが変化するように保持する保持部材10、及びアンテナ２の受信時の誘導起電力により駆動されてアンテナ２から識別信号Ｓを送信するＩＣ回路６を備え、外力印可時に磁性体３又は導電体４との接近又は離隔によりアンテナ２の送受信周波数ｆをシフトさせて識別信号Ｓの送信を停止させてなるものである。好ましくは、アンテナ２又はＩＣ回路６にコンデンサ５を含め、アンテナ２とコンデンサ５とで形成される共振回路７（図５参照）の共振周波数ｆを磁性体３又は導電体４との接近又は離隔によりシフトさせる。Referring to the embodiment of FIG. 1, a frequency shift type RFID device according to the present invention includes a holding member 10 that holds a coiled antenna 2 and a magnetic body 3 or a conductor 4 so that a distance W is changed by an external force, and An IC circuit 6 that is driven by an induced electromotive force at the time of reception of the antenna 2 andtransmits an identification signal Sfrom the antenna 2 is provided, and when the external force is applied, the transmission / reception frequency f of the antenna 2 by approaching or separating from the magnetic body 3 or the conductor 4 Andthe transmission of the identification signal S is stopped . Preferably, the capacitor 2 is included in the antenna 2 or the IC circuit 6, and the resonance frequency f of the resonance circuit 7 (see FIG. 5) formed by the antenna 2 and the capacitor 5 is set close to or separated from the magnetic body 3 or the conductor 4. Shift by.
更に好ましくは、図１に示すように、保持部材10に外力により伸縮又は変形する弾性又は塑性の変形部材13を含め、その変形部材13を介してアンテナ２と磁性体３又は導電体４とを保持する。または、図２〜図４及び図７〜図９に示すように、保持部材10に外力に抗して固定される固定部材11とその固定部材11に係止されつつ外力により変位又は変形する可動部材12とを含め、アンテナ２と磁性体３又は導電体４との一方を固定部材11に保持すると共に他方を可動部材12に保持する。可動部材12には、外力印可時に伸縮又は変形する弾性又は塑性の変形部材13を含めることができる。例えば図２に示すように、固定部材11及び可動部材12の一方を軸芯状とし他方をそれに遊嵌する孔付き盤状とすることができる。また図３に示すように、固定部材11及び可動部材12の一方をシリンダ状とし他方をそれに遊嵌するピストン状としてもよい。 More preferably, as shown in FIG. 1, the holding member 10 includes an elastic or plastic deformation member 13 that expands or contracts by an external force, and the antenna 2 and the magnetic body 3 or the conductor 4 are connected via the deformation member 13. Hold. Alternatively, as shown in FIGS. 2 to 4 and 7 to 9, the fixing member 11 fixed to the holding member 10 against the external force and the movable member that is displaced or deformed by the external force while being locked to the fixing member 11. Including the member 12, one of the antenna 2 and the magnetic body 3 or the conductor 4 is held by the fixed member 11 and the other is held by the movable member 12. The movable member 12 can include an elastic or plastic deformation member 13 that expands or contracts when an external force is applied. For example, as shown in FIG. 2, one of the fixed member 11 and the movable member 12 can be formed into an axial core shape and the other can be formed into a disk shape with a hole that is loosely fitted thereto. Further, as shown in FIG. 3, one of the fixed member 11 and the movable member 12 may be a cylinder and the other may be a piston that is loosely fitted thereto.
本発明による周波数シフト形ＲＦＩＤデバイスは、コイル状アンテナ２とそのアンテナ２の受信時の誘導起電力により駆動されてアンテナ２から識別信号Ｓを送信するＩＣ回路６とを備え、そのアンテナ２と磁性体３又は導電体４とを外力により間隔Ｗが変化するように保持し、外力印可時に磁性体３又は導電体４との接近又は離隔によりアンテナ２の送受信周波数ｆをシフトさせて識別信号Ｓの送信を停止させるので、次の顕著な効果を奏する。The frequency shift type RFID device according to the present invention includes a coiled antenna 2 and an IC circuit 6 that is driven by an induced electromotive force at the time of reception of the antenna 2 andtransmits an identification signal Sfrom the antenna 2. The body 3 or the conductor 4 is held so that the interval W is changed by an external force, and the transmission / reception frequency f of the antenna 2 is shifted by the approach or separation from the magnetic body 3 or the conductor 4 when an external force is applied. Runodestops the transmission, offers the following remarkable effects.
（イ）外力によってコイル状アンテナ２の送受信周波数ｆがシフトするので、そのシフトによって特定の送受信周波数ｆによる識別信号Ｓの送信を停止させることにより、デバイスに加わる歪・変位・圧力等の力学的変化を無電力で検出することができる。
（ロ）また、コイル状アンテナ２により導電率の高い媒質中でも減衰しにくい低周波数ｆで送受信するので、そのような媒質が介在する環境下でもＲＦＩＤ通信が可能であり、地中又は水中にデバイスを設置することも可能である。
（ハ）従って、水中又は地中に沈設する構造物（物体等）の接地部にＲＦＩＤデバイスを取り付けて設置面との接触／非接触の状態を監視する場合や、コンクリートを打設する枠体内にＲＦＩＤデバイスを取り付けてコンクリートの充填を管理する場合等に有効に利用することができる。
（ニ）ＲＦＩＤデバイスの構成が簡単であって安価に製造可能であり、しかも電池を搭載する必要がないので、コスト面及び作業面で負担の少ないデバイスとすることができる。(B) Since the transmission / reception frequency f of the coiled antenna 2 is shifted by an external force, the transmission of the identification signal S at the specific transmission / reception frequency f is stopped by the shift, so that the strain, displacement, pressure, etc. applied to the device Changes can be detected without power.
(B) Further, since the coiled antenna 2 transmits and receives at a low frequency f that is difficult to attenuate even in a medium with high conductivity, RFID communication is possible even in an environment where such a medium is interposed, and the device is in the ground or in water. It is also possible to install.
(C) Therefore, when attaching an RFID device to the grounding part of a structure (object, etc.) submerged in the water or in the ground to monitor the contact / non-contact state with the installation surface, or in the frame where concrete is placed It can be used effectively when an RFID device is attached to the container to manage filling of concrete.
(D) Since the configuration of the RFID device is simple and can be manufactured at low cost, and it is not necessary to mount a battery, the device can be reduced in cost and work.
図１は、水中又は地中に沈設する構造物37と設置面（例えば地盤面）Ｅとの接触／非接触の状態監視に本発明のＲＦＩＤデバイス１を適用した実施例を示す。図示例のＲＦＩＤデバイス１は、コイル状アンテナ２と、比透磁率μが１より大きい磁性体３と、そのアンテナ２及び磁性体３を外力Ｆによって間隔Ｗが変化するように保持する保持部材10と、アンテナ２の受信時の誘導起電力により駆動されるＩＣ回路６とを有する。図示例では、アンテナ２をシリンダ状に形成し、そのシリンダ状アンテナ２の一端側に固定部材11を固定し、シリンダ状アンテナ２の内側に配置した弾性又は塑性の変形部材13の一端を固定部材11に結合すると共にその他端にシリンダ内径より小径の磁性体３を保持し、固定部材11と変形部材13とで保持部材10を構成している（同図（Ｂ）参照）。またＩＣ回路６を固定部材11上に取り付けている。ただし、固定部材11は本発明に必須のものではなく、変形可能な保持部材10の両端にシリンダ状アンテナ２と磁性体３とをそれぞれ取り付け、ＩＣ回路６をシリンダに支持してもよい。また後述するように、磁性体３に代えて、導電体４を用いて本発明のＲＦＩＤデバイス１とすることができる。 FIG. 1 shows an embodiment in which the RFID device 1 of the present invention is applied to monitoring the contact / non-contact state between a structure 37 submerged in water or in the ground and an installation surface (for example, ground surface) E. The illustrated RFID device 1 includes a coiled antenna 2, a magnetic body 3 having a relative permeability μ larger than 1, and a holding member 10 that holds the antenna 2 and the magnetic body 3 so that the interval W is changed by an external force F. And an IC circuit 6 driven by an induced electromotive force at the time of reception of the antenna 2. In the illustrated example, the antenna 2 is formed in a cylinder shape, a fixing member 11 is fixed to one end side of the cylindrical antenna 2, and one end of an elastic or plastic deformation member 13 disposed inside the cylindrical antenna 2 is a fixing member. 11 and a magnetic member 3 having a diameter smaller than the inner diameter of the cylinder is held at the other end, and the holding member 10 is constituted by the fixing member 11 and the deforming member 13 (see FIG. 4B). The IC circuit 6 is mounted on the fixing member 11. However, the fixing member 11 is not essential to the present invention, and the cylindrical antenna 2 and the magnetic body 3 may be attached to both ends of the deformable holding member 10 to support the IC circuit 6 on the cylinder. As will be described later, the RFID device 1 of the present invention can be obtained by using the conductor 4 instead of the magnetic body 3.
図示例の変形部材13は、例えば固定部材11とアンテナ２との間隔Ｍより大きい初期長さＮを有し、その初期長さＮにおいてアンテナ２と磁性体３とを間隔W1（＝Ｎ−Ｍ）だけ離して保持しているが（図１（Ａ）参照）、シリンダ軸線方向の外力Ｆを受けると収縮してアンテナ２と磁性体３とを接近させる。同図（Ｃ）に示すように外力Ｆにより変形部材13が長さＭにまで収縮すると、アンテナ２と磁性体３とが間隔W2（≒０）となり、磁性体３がアンテナ２とほぼ重なる。変形部材13の一例はバネ、ゴム等の弾性変形材製であるが、アンテナ２及び磁性体３の間隔Ｗを外力Ｆの除去時に復帰させる必要がない場合は、変形部材13を金属又は合成樹脂等の塑性変形材製としてもよい。また図４に示すように、変形部材13を、外力Ｆにより開放される開閉栓14を有すると共にその開閉栓14の開放時に気体又は液体が進入又は排出されて膨張又は収縮するものとしてもよい。図４の変形部材13は、初期状態において開閉栓14が閉鎖されて収縮しており、アンテナ２と磁性体３とを間隔W1だけ離して保持しているが、外力Ｆの印可時に開閉栓14が外れ又は破壊されると気体又は液体が進入して膨張し（同図（Ｂ）の黒矢印参照）、アンテナ２と磁性体３とを間隔W2（≒０）にまで接近させる。変形部材13の内側への気体又は液体の進入が促進されるように、例えば初期状態において変形部材13の内側を負圧又は真空としておくことができる。 The deformable member 13 in the illustrated example has an initial length N that is larger than the interval M between the fixing member 11 and the antenna 2, for example, and at the initial length N, the antenna 2 and the magnetic body 3 are separated by an interval W1 (= N−M). ) (See FIG. 1 (A)), but when the external force F in the cylinder axial direction is received, the antenna 2 and the magnetic body 3 are brought close to each other. When the deformable member 13 contracts to the length M by the external force F as shown in FIG. 5C, the distance between the antenna 2 and the magnetic body 3 becomes W2 (≈0), and the magnetic body 3 almost overlaps the antenna 2. An example of the deformable member 13 is made of an elastic deformable material such as a spring or rubber. However, if it is not necessary to return the distance W between the antenna 2 and the magnetic body 3 when the external force F is removed, the deformable member 13 is made of metal or synthetic resin. It is good also as a product made from plastic deformation materials, such as. As shown in FIG. 4, the deformable member 13 may have an opening / closing plug 14 that is opened by an external force F, and expand or contract by gas or liquid entering or discharging when the opening / closing plug 14 is opened. The deformable member 13 of FIG. 4 is contracted by closing the opening / closing plug 14 in the initial state, and holds the antenna 2 and the magnetic body 3 apart by a distance W1, but the opening / closing plug 14 is applied when the external force F is applied. When it is detached or destroyed, gas or liquid enters and expands (see the black arrow in FIG. 5B), and the antenna 2 and the magnetic body 3 are brought close to the interval W2 (≈0). For example, in the initial state, the inside of the deformable member 13 can be set to a negative pressure or a vacuum so that the gas or liquid enters the inside of the deformable member 13 is promoted.
図示例のコイル状アンテナ２はコンデンサ５（同調コンデンサ）を含み、アンテナ２とコンデンサ５とで共振回路７（図５参照）を形成している。なお、図示例ではコンデンサ５とＩＣ回路６とを分離しているが、コンデンサ５をＩＣ回路６に含めてもよい。共振回路７はアンテナ２のインダクタンスＬとコンデンサ５の容量Ｃとで定まる共振周波数f0（＝１／２π（Ｌ・Ｃ）1/2）を有しており、アンテナ２のインダクタンスＬはアンテナ２と磁性体３との間隔Ｗにより変化する。例えばアンテナ２と磁性体３とが間隔W1のときはアンテナ２がインダクタンスL1となり、共振回路７が共振周波数f1（＝１／２π（L1・Ｃ）1/2）となる。これに対しアンテナ２と磁性体３とが間隔W2（＜W1）に接近したときは、両者の結合状態が強くなり、アンテナ２のインダクタンスL2が大きくなり、共振回路７がより低い共振周波数f2（＝１／２π（L2・Ｃ）1/2）にシフトする。また、アンテナ２と磁性体３との間隔W2が小さくなると、磁性体３の導電性の影響で渦電流損が発生してアンテナ２のＱ特性が低下するので、発生磁界が弱まり、共振周波数f2における振幅（電圧）が共振周波数f1に比して低くなる。The coiled antenna 2 in the illustrated example includes a capacitor 5 (tuning capacitor), and the antenna 2 and the capacitor 5 form a resonance circuit 7 (see FIG. 5). In the illustrated example, the capacitor 5 and the IC circuit 6 are separated, but the capacitor 5 may be included in the IC circuit 6. The resonance circuit 7 has a resonance frequency f0 (= 1 / 2π (L · C)1/2 ) determined by the inductance L of the antenna 2 and the capacitance C of the capacitor 5, and the inductance L of the antenna 2 is the antenna 2. And the distance W between the magnetic body 3 and the magnetic body 3. For example, when the distance between the antenna 2 and the magnetic body 3 is W1, the antenna 2 has an inductance L1, and the resonance circuit 7 has a resonance frequency f1 (= 1 / 2π (L1 · C)1/2 ). On the other hand, when the antenna 2 and the magnetic body 3 approach the distance W2 (<W1), the coupling state between the two becomes strong, the inductance L2 of the antenna 2 increases, and the resonance circuit 7 has a lower resonance frequency f2 ( = 1 / 2π (L2 · C)1/2 ). Further, if the distance W2 between the antenna 2 and the magnetic body 3 is reduced, an eddy current loss occurs due to the conductivity of the magnetic body 3 and the Q characteristic of the antenna 2 is lowered, so that the generated magnetic field is weakened and the resonance frequency f2 is reduced. The amplitude (voltage) at becomes lower than the resonance frequency f1.
共振回路７の共振周波数f0は、磁性体３に代えてアルミニウム・金・銅・銀等の導電体４を用い、その導電体４とアンテナ２との間隔Ｗを変化させることによりシフトさせることもできる。この場合は、図示例において保持部材10によりアンテナ２と導電体４とを外力Ｆで間隔Ｗが変化するように保持し、間隔W1の初期状態における共振回路７の共振周波数f1（＝１／２π（L1・Ｃ）1/2）に対して、外力により導電体４を間隔W2（＜W1）に接近させてアンテナ２のインダクタンスL3を小さくすることにより、共振回路７をより高い共振周波数f3（＝１／２π（L3・Ｃ）1/2）にシフトさせる。磁性体３を用いた場合と導電体４を用いた場合とでは共振回路７の共振周波数f0が高低どちら側にシフトするかが異なりうるが、磁性体３に代えて導電体４を用いた場合も、外力により共振周波数f0がシフトするＲＦＩＤデバイス１とすることができる。The resonance frequency f0 of the resonance circuit 7 is shifted by using a conductor 4 such as aluminum, gold, copper, or silver instead of the magnetic body 3 and changing the distance W between the conductor 4 and the antenna 2. You can also. In this case, in the illustrated example, the holding member 10 holds the antenna 2 and the conductor 4 so that the interval W is changed by the external force F, and the resonance frequency f1 (= 1 / 2π) of the resonance circuit 7 in the initial state of the interval W1. (L1 · C)1/2 ), by reducing the inductance L3 of the antenna 2 by bringing the conductor 4 closer to the interval W2 (<W1) by an external force, the resonance circuit 7 has a higher resonance frequency f3 ( = 1 / 2π (L3 · C)1/2 ). Although the case where the magnetic body 3 is used and the case where the conductor 4 is used may differ depending on which side the resonance frequency f0 of the resonance circuit 7 shifts, the conductor 4 is used instead of the magnetic body 3. Also in this case, the RFID device 1 in which the resonance frequency f0 is shifted by an external force can be obtained.
図示例のＩＣ回路６は、コイル状アンテナ２の受信時の誘導起電力によって駆動され、アンテナ２に対して識別信号Ｓを供給する。例えば図１０に示すＩＣ回路43と同様に、ＩＣ回路６に電源回路（整流回路等）44と制御回路45と記憶回路46と送受信回路47とを組み込み、その記憶回路46に識別信号Ｓを記憶しておくことができる。例えばアンテナ２と磁性体３（又は導電体４）とが間隔W1の初期状態において、読み出し装置20（図１０及び図１１参照）からの共振周波数f1の読み出し電磁波Ｒ（磁場）をアンテナ２が受信すると、その誘導起電力によってＩＣ回路６が駆動される。ＩＣ回路６に過剰な電圧（エネルギー）が入力されないように、必要に応じてアンテナ２とＩＣ回路６との間にＺＤツェナーダイオード等の負荷抵抗を接続して電圧を調節することができる。 The IC circuit 6 in the illustrated example is driven by an induced electromotive force at the time of reception of the coiled antenna 2 and supplies an identification signal S to the antenna 2. For example, similarly to the IC circuit 43 shown in FIG. 10, a power supply circuit (rectifier circuit or the like) 44, a control circuit 45, a storage circuit 46, and a transmission / reception circuit 47 are incorporated in the IC circuit 6, and the identification signal S is stored in the storage circuit 46. Can be kept. For example, the antenna 2 receives the read electromagnetic wave R (magnetic field) having the resonance frequency f1 from the reading device 20 (see FIGS. 10 and 11) in the initial state where the antenna 2 and the magnetic body 3 (or the conductor 4) are at the interval W1. Then, the IC circuit 6 is driven by the induced electromotive force. The voltage can be adjusted by connecting a load resistor such as a ZD Zener diode between the antenna 2 and the IC circuit 6 as necessary so that an excessive voltage (energy) is not input to the IC circuit 6.
読み出し電磁波Ｒによりアンテナ２に生じた誘導起電力は、その電磁波Ｒ（磁場）を打ち消すような共振周波数f1の磁場（以下、応答電磁波という）を生ずる。誘導起電力で駆動されたＩＣ回路６は、アンテナ２に識別信号Ｓを供給し、応答電磁波の搬送波に識別信号Ｓを変調する。読み出し装置20は、応答電磁波を復調することにより、識別信号Ｓを読み出すことができる。すなわち、アンテナ２と磁性体３（又は導電体４）とが間隔W1の初期状態においては、読み出し装置20のアンテナ21とＲＦＩＤデバイス１のアンテナ２とを共振周波数f1により磁気結合させて識別信号Ｓを伝達し、読み出し装置20により識別信号Ｓを読み取ることができる。 The induced electromotive force generated in the antenna 2 by the read electromagnetic wave R generates a magnetic field (hereinafter referred to as response electromagnetic wave) having a resonance frequency f1 that cancels the electromagnetic wave R (magnetic field). The IC circuit 6 driven by the induced electromotive force supplies the identification signal S to the antenna 2 and modulates the identification signal S to the carrier wave of the response electromagnetic wave. The reading device 20 can read the identification signal S by demodulating the response electromagnetic wave. That is, in the initial state where the distance between the antenna 2 and the magnetic material 3 (or the conductor 4) is W1, the antenna 21 of the reading device 20 and the antenna 2 of the RFID device 1 are magnetically coupled by the resonance frequency f1 to thereby identify the identification signal S. And the identification signal S can be read by the reading device 20.
しかし、アンテナ２と磁性体３（又は導電体４）とが接近して間隔W2になると、共振回路７が共振周波数f2にシフトするので、アンテナ２が共振周波数f1の読み出し信号Ｒを受信しても十分な誘導起電力（振幅）を得ることができず、読み出し装置20により識別信号Ｓを読み取ることができない通信不能状態となる。すなわち、読み出し装置20とＲＦＩＤデバイス１との間の共振周波数f1による識別信号Ｓの読み取りが停止することから、デバイス１に加わる外力Ｆの変化を検出することができる。このような識別信号Ｓの読み取り（ＯＮ）とその停止（ＯＦＦ）とは明確に区別できることが望ましく、そのためには接近によりアンテナ２の共振周波数f1を大きく変化させる炭素鋼・ケイ素鋼・コバルト・パーマロイ等の比透磁率μが１よりはるかに大きい強磁性体３を用いることが有効である。 However, when the antenna 2 and the magnetic body 3 (or the conductor 4) come close to each other and the interval W2 is reached, the resonance circuit 7 shifts to the resonance frequency f2, so that the antenna 2 receives the read signal R having the resonance frequency f1. However, a sufficient induced electromotive force (amplitude) cannot be obtained, and the identification signal S cannot be read by the reading device 20 and communication is disabled. That is, since the reading of the identification signal S at the resonance frequency f1 between the reading device 20 and the RFID device 1 is stopped, a change in the external force F applied to the device 1 can be detected. It is desirable to clearly distinguish between reading (ON) and stopping (OFF) of the identification signal S. For this purpose, carbon steel / silicon steel / cobalt / permalloy that greatly changes the resonance frequency f1 of the antenna 2 when approached. It is effective to use a ferromagnetic material 3 having a relative magnetic permeability μ much larger than 1.
［実験例１］
本発明のＲＦＩＤデバイス１により力学的変化が検出できることを確認するため、図５（Ａ）に示すように、線径φ＝0.5mmの導線によるコイル径Φ＝20mm、ターン数（巻き数）Ｔ＝20、幅10mmのコイル状アンテナ（受信アンテナ）２とコンデンサ５とを並列接続して共振周波数f0＝135kHzの受信共振回路７を形成し、その受信アンテナ２と近傍に保持した炭素鋼製の強磁性体３との間隔Ｗを変化させたときの共振回路７の誘導起電力Voutの変化を測定する実験を行なった。本実験では、同じく線径φ＝0.5mmの導線で形成したコイル径Φ＝20mm、ターン数Ｔ＝20、幅10mmのコイル状の送信アンテナ21とコンデンサ22とを直列接続して共振周波数f0＝135kHzの送信共振回路23を形成し、その送信共振回路23にマルチファンクションシンセサイザー28を接続して読み出し装置とした。また、その読み出し装置の送信アンテナ21にシンセサイザー28から駆動電圧＝10Vpp（＝3.54Vrms）を駆動周波数130〜138kHzで掃引しながら印加し、そのときに受信共振回路７で発生する誘導起電力Voutを受信共振回路７に接続したデジタルオシロスコープ29で測定した。[Experimental Example 1]
In order to confirm that a mechanical change can be detected by the RFID device 1 of the present invention, as shown in FIG. 5A, the coil diameter Φ = 20 mm, the number of turns (the number of turns) T of a conducting wire having a wire diameter φ = 0.5 mm. = 20, 10 mm wide coiled antenna (receiving antenna) 2 and capacitor 5 are connected in parallel to form a receiving resonance circuit 7 having a resonance frequency f0 = 135 kHz, and is made of carbon steel held in the vicinity of the receiving antenna 2 An experiment was conducted to measure the change in the induced electromotive force Vout of the resonance circuit 7 when the interval W with the ferromagnetic material 3 was changed. In this experiment, a coil-shaped transmitting antenna 21 and a capacitor 22 having a coil diameter Φ = 20 mm, a turn diameter T = 20, and a width 10 mm, each formed of a conducting wire having a diameter φ = 0.5 mm, are connected in series, and a resonance frequency f0 is obtained. = 135 kHz transmission resonance circuit 23 was formed, and a multifunction synthesizer 28 was connected to the transmission resonance circuit 23 to obtain a reading device. In addition, a drive voltage = 10 Vpp (= 3.54 Vrms) is applied to the transmission antenna 21 of the readout device while sweeping at a drive frequency of 130 to 138 kHz from the synthesizer 28, and the induced electromotive force Vout generated at the reception resonance circuit 7 at that time is applied. Measurement was performed with a digital oscilloscope 29 connected to the reception resonance circuit 7.
先ず図５（Ｂ）に示すように、送信アンテナ21と受信アンテナ２とを同一軸線上で間隔Ｄ＝100mmだけ離したうえで、強磁性体３の存在しない状態の誘導起電力Voutを測定した（case１）。次に同図（Ｃ）に示すように受信アンテナ２の近傍に強磁性体３を間隔W1＝15mmで保持した状態で誘導起電力Voutを測定し（case２）、更に同図（Ｄ）に示すように受信アンテナ２と強磁性体３とがほぼ重なる間隔W2≒０mmに接近させた状態で誘導起電力Voutを測定した（case３）。case１〜３の実験結果を図６のグラフに示す。 First, as shown in FIG. 5B, the transmission antenna 21 and the reception antenna 2 are separated from each other by a distance D = 100 mm on the same axis, and the induced electromotive force Vout in the state where the ferromagnetic material 3 is not present is measured. (Case 1). Next, as shown in FIG. 6C, the induced electromotive force Vout is measured in the state where the ferromagnetic material 3 is held in the vicinity of the receiving antenna 2 at the interval W1 = 15 mm (case 2), and further shown in FIG. In this manner, the induced electromotive force Vout was measured in a state where the receiving antenna 2 and the ferromagnetic material 3 were close to each other at a distance W2≈0 mm (case 3). The experimental results of cases 1 to 3 are shown in the graph of FIG.
図６のcase１のグラフは、強磁性体３の存在しない場合は共振周波数f0＝135kHzにおいて誘導起電力Vout≒30mVppとなることを示している。またcase２のグラフは、受信アンテナ２の近傍（間隔W1＝15mm）に強磁性体３を保持することで受信アンテナ２の受信周波数（共振周波数）が若干低くなると共にその誘導起電力Voutが小さくなり、共振周波数f0＝135kHzにおいて誘導起電力Vout≒26mVppとなることを示している。更にcase３のグラフは、受信アンテナ２と強磁性体３とを接近させた（間隔W2≒０mm）ときに受信アンテナ２の受信周波数（共振周波数）が更に低くなると共にその誘導起電力Voutが更に小さくなり、共振周波数f0＝135kHzにおいて誘導起電力Vout≒18mVppとなることを示している。The graph of case 1 in FIG. 6 shows that the induced electromotive force Vout≈30 mVpp at the resonance frequency f0 = 135 kHz when the ferromagnetic material 3 is not present. The graph of case 2 shows that the reception frequency (resonance frequency) of the reception antenna 2 is slightly lowered and the induced electromotive force Vout is reduced by holding the ferromagnetic material 3 in the vicinity of the reception antenna 2 (interval W1 = 15 mm). This shows that the induced electromotive force Vout≈26 mVpp at the resonance frequency f0 = 135 kHz. Furthermore, the graph of case 3 shows that when the receiving antenna 2 and the ferromagnetic material 3 are brought close to each other (interval W2≈0 mm), the receiving frequency (resonance frequency) of the receiving antenna 2 is further lowered and the induced electromotive force Vout is further reduced. Thus, it is shown that the induced electromotive force Vout≈18 mVpp at the resonance frequency f0 = 135 kHz.
図６のグラフから、例えば誘導起電力Vout≒20.0mVppで駆動されるＩＣ回路６を用いれば、強磁性体３が間隔W1＝15mmで保持されているときは共振周波数f0＝135kHzの読み取り信号に応じて識別信号Ｓが読み取れるが、強磁性体３が間隔W2≒０mmに接近したときに共振周波数f0＝135kHzの読み取り信号では識別信号Ｓが読み取れない通信不能状態となることが分かる。すなわち本実験により、磁性体３が間隔W1のとき（離隔しているとき）はＩＣ回路６が動作する誘導起電力を発生するが、間隔W2のとき（接近したとき）はＩＣ回路６が動作しない電圧まで誘導起電力が低下するようにアンテナ２及び磁性体３を設計しておけば、識別信号Ｓの読み取り停止により力学的変化を検出できるＲＦＩＤデバイス１とすることができることを確認できた。From the graph of FIG. 6, for example, when the IC circuit 6 driven with the induced electromotive force Vout≈20.0 mVpp is used, when the ferromagnetic material 3 is held at the interval W1 = 15 mm, the read signal with the resonance frequency f0 = 135 kHz. The identification signal S can be read in response to the above, but it can be seen that when the ferromagnetic material 3 approaches the interval W2≈0 mm, the identification signal S cannot be read by the read signal having the resonance frequency f0 = 135 kHz. That is, according to this experiment, when the magnetic body 3 is at the interval W1 (when separated), an induced electromotive force is generated to operate the IC circuit 6, but when the magnetic body 3 is at the interval W2 (when approaching), the IC circuit 6 is operated. It can be confirmed that if the antenna 2 and the magnetic body 3 are designed so that the induced electromotive force is reduced to a voltage that does not, the RFID device 1 can detect the mechanical change by stopping the reading of the identification signal S.
なお、コイル状アンテナ２の送受信周波数（共振周波数）ｆは、コイル径Φやコンデンサ５の容量Ｃ等を適当に選択することで調整可能であるが、導電率の高い媒質中でも減衰しにくい低周波数とすることが望ましい。例えば送受信周波数（共振周波数）ｆを、国際規格（ISO／IEC）で標準化が進められている長波帯（135kHz以下）又は短波帯（13.56MHz）とする。また、磁性体３（又は導電体４）の接近による送受信周波数（共振周波数）ｆのシフト量や振幅ピークの低減量も、磁性体３（又は導電体４）の比透磁率μの大きさや棒状、円柱状、角柱状、板状、中空筒状等の形状を適当に選択することで調整することができる。接近時にＩＣ回路６が動作しない電圧まで誘導起電力が低下するようにアンテナ２及び磁性体３（又は導電体４）のコイル径Φ、ターン数（巻き数）Ｔ、非透磁率μ、形状等を設計しておけば、識別信号Ｓの読み取り停止により歪・変位・圧力等の力学的変化を検出できるパッシブ型のＲＦＩＤデバイス１とすることができる。 Note that the transmission / reception frequency (resonance frequency) f of the coiled antenna 2 can be adjusted by appropriately selecting the coil diameter Φ, the capacitance C of the capacitor 5, etc., but it is a low frequency that is not easily attenuated even in a medium with high conductivity. Is desirable. For example, the transmission / reception frequency (resonance frequency) f is set to a long wave band (135 kHz or less) or a short wave band (13.56 MHz), which is being standardized by an international standard (ISO / IEC). Further, the shift amount of the transmission / reception frequency (resonance frequency) f and the reduction amount of the amplitude peak due to the approach of the magnetic body 3 (or the conductor 4) are also the magnitude of the relative permeability μ of the magnetic body 3 (or the conductor 4) and the bar shape. It can be adjusted by appropriately selecting a shape such as a columnar shape, a prismatic shape, a plate shape, or a hollow cylindrical shape. The coil diameter Φ, the number of turns (number of turns) T, the non-permeability μ, the shape, etc. of the antenna 2 and the magnetic body 3 (or the conductor 4) so that the induced electromotive force is lowered to a voltage at which the IC circuit 6 does not operate when approaching. Is designed, a passive RFID device 1 that can detect mechanical changes such as strain, displacement, and pressure by stopping reading the identification signal S can be obtained.
図１の実施例では、同図（Ｄ）に示すように、上述した単数又は複数のＲＦＩＤデバイス１を水中又は地中に沈設する構造物37の地盤Ｅとの接触部（例えばケーソンの底壁外側）に取り付け、構造物37の沈設作業時に構造物37の内側の読み出し装置20によって各ＲＦＩＤデバイス１の識別信号Ｓを繰り返し読み取り、読み取りの停止したＲＦＩＤデバイス１を検出する。読み出し装置20は、低周波数の読み出し信号Ｒを用いる点を除き、図１０に示す読み出し装置20と同様の構成とすることができる。ＲＦＩＤデバイス１は、構造物37が地盤Ｅと接触するまで識別信号Ｓの読み取りが可能であるが、上述したように構造物37が地盤Ｅと接触して外力が加わると識別信号Ｓの読み取りが停止するので、識別信号Ｓの読み取りの停止したＲＦＩＤデバイス１の取り付け部位Ｐから構造物37の各接触部における地盤Ｅとの接触／非接触の状態を検知することができる。なお、ＲＦＩＤデバイス１のシリンダ状アンテナ２及び固定部材11は構造物37の接触部に窪みを設けて埋設することができ、埋設することでＲＦＩＤデバイス１が構造物37の沈設の障害となるのを避けることができる。なお、外力Ｆの除去時にアンテナ２及び磁性体３（又は導電体４）の間隔Ｗが復帰するように保持部材10を弾性変形材製とした場合は、読み出し装置20で識別信号Ｓの読み出しの再開したＲＦＩＤデバイス１を検出することで、構造物37の各接触部の地盤Ｅからの離陸（非接触）を検知することも可能である。 In the embodiment of FIG. 1, as shown in FIG. 1D, a contact portion (for example, the bottom wall of a caisson) of a structure 37 that sunk the above-described one or more RFID devices 1 in water or in the ground. The identification signal S of each RFID device 1 is repeatedly read by the reading device 20 inside the structure 37 when the structure 37 is set, and the RFID device 1 whose reading has been stopped is detected. The reading device 20 can have the same configuration as the reading device 20 shown in FIG. 10 except that a low-frequency read signal R is used. The RFID device 1 can read the identification signal S until the structure 37 contacts the ground E. However, as described above, when the structure 37 contacts the ground E and an external force is applied, the identification signal S can be read. Since it stops, the contact / non-contact state with the ground E in each contact part of the structure 37 can be detected from the attachment part P of the RFID device 1 where the reading of the identification signal S is stopped. In addition, the cylindrical antenna 2 and the fixing member 11 of the RFID device 1 can be embedded by providing a depression in the contact portion of the structure 37, and the RFID device 1 becomes an obstacle to the setting of the structure 37 by being embedded. Can be avoided. When the holding member 10 is made of an elastic deformation material so that the interval W between the antenna 2 and the magnetic body 3 (or the conductor 4) is restored when the external force F is removed, the reading device 20 reads the identification signal S. By detecting the restarted RFID device 1, it is possible to detect takeoff (non-contact) from the ground E of each contact portion of the structure 37.
こうして本発明の目的である「コイル状アンテナを用いて力学的変化を検出できるパッシブ型のＲＦＩＤデバイス」の提供を達成することができる。 Thus, the provision of a “passive RFID device that can detect a mechanical change using a coiled antenna”, which is an object of the present invention, can be achieved.
以上、図１を参照して外力によりアンテナ２と磁性体３（又は導電体４）とを接近させて送受信周波数ｆをシフトさせるＲＦＩＤデバイス１について説明したが、本発明のＲＦＩＤデバイス１では外力によりアンテナ２と磁性体３（又は導電体４）とを離隔させて送受信周波数ｆをシフトさせることも可能である。例えば、外力のない初期状態において図６のcase３のグラフ（間隔W2≒０mm）となるようにアンテナ２と強磁性体３とを保持部材10により接近させた状態で保持し、外力印加時にアンテナ２と強磁性体３とを離隔させてcase２のグラフ（間隔W1＝15mm）となるように保持部材10を変形させる。この場合は、読み出し装置20で識別信号Ｓの読み出しの開始したＲＦＩＤデバイス１を検出することにより、ＲＦＩＤデバイス１の取り付け部位Ｐの力学的変化を検知することができる。 The RFID device 1 that shifts the transmission / reception frequency f by causing the antenna 2 and the magnetic body 3 (or the conductor 4) to approach each other with an external force has been described with reference to FIG. It is also possible to shift the transmission / reception frequency f by separating the antenna 2 and the magnetic body 3 (or the conductor 4). For example, in the initial state where there is no external force, the antenna 2 and the ferromagnetic material 3 are held close to each other by the holding member 10 so that the case 3 graph (interval W2≈0 mm) in FIG. The holding member 10 is deformed so that the ferromagnetic material 3 is separated from the magnetic body 3 and the graph of case 2 (interval W1 = 15 mm) is obtained. In this case, it is possible to detect a mechanical change of the attachment site P of the RFID device 1 by detecting the RFID device 1 from which the reading of the identification signal S is started by the reading device 20.
なお、図１の実施例ではシリンダ状アンテナ２の内側に磁性体３（又は導電体４）を保持しているが、例えば図３の実施例に示すように、シリンダ状の固定部12に磁性体３（又は導電体４）を保持し、その内側に遊嵌するピストン状のコイル状アンテナ２と組み合わせて本発明のＲＦＩＤデバイス１とすることも可能である。同図は、有底シリンダ状固定部12の側壁及び／又は底壁を磁性体３（又は導電体４）により形成し、そのシリンダ状固定部12の内側に弾性又は塑性の変形部材13を介して棒状のコイル状アンテナ２を遊嵌させたものである。変形部材13は初期状態において棒状アンテナ２をシリンダ状固定部12から突出させて保持し、アンテナ２と磁性体３（又は導電体４）とを間隔W1だけ離しているが（同図（Ａ）参照）、外力Ｆを受けると棒状アンテナ２がシリンダ状固定部12の内側に収納されてアンテナ２と磁性体３（又は導電体４）とが間隔W2（≒０）となり、磁性体３がアンテナ２とほぼ重なってアンテナ２の送受信周波数をシフトさせる。 In the embodiment of FIG. 1, the magnetic body 3 (or conductor 4) is held inside the cylindrical antenna 2, but for example, as shown in the embodiment of FIG. The RFID device 1 of the present invention may be combined with the piston-like coiled antenna 2 that holds the body 3 (or the conductor 4) and loosely fits inside the body 3 (or the conductor 4). In the figure, the bottom wall and / or bottom wall of the bottomed cylindrical fixing portion 12 is formed of the magnetic body 3 (or the conductor 4), and an elastic or plastic deformation member 13 is interposed inside the cylindrical fixing portion 12. A rod-shaped coiled antenna 2 is loosely fitted. In the initial state, the deformable member 13 holds the rod-shaped antenna 2 so as to protrude from the cylindrical fixing portion 12, and the antenna 2 and the magnetic body 3 (or conductor 4) are separated from each other by a distance W1 (FIG. 2A). When the external force F is received, the rod-shaped antenna 2 is housed inside the cylindrical fixing portion 12, and the distance between the antenna 2 and the magnetic body 3 (or the conductor 4) is W2 (≈0). The transmission / reception frequency of the antenna 2 is shifted so as to substantially overlap with 2.
図２は、図１２に示すようなトンネルの地山Ｅとセントル（覆工型枠）32との間に打設する覆工コンクリートＣの充填状態の監視に本発明のＲＦＩＤデバイス１を適用した実施例を示す。図示例のＲＦＩＤデバイス１も、コイル状アンテナ２と磁性体３（又は導電体４）とを外力Ｆにより間隔Ｗが変化するように保持する保持部材10と、アンテナ２の受信時の誘導起電力で駆動されるＩＣ回路６とを有する。図示例の保持部材10は、力学的変化を検出する部位に外力に抗して固定される固定部材11と、その固定部材11に係止されつつ外力により変位又は変形する可動部材12とを有し、アンテナ２及び強磁性体３（又は導電体４）の一方を固定部材11に保持すると共に他方を可動部材12に保持している。 In FIG. 2, the RFID device 1 of the present invention is applied to the monitoring of the filling state of the lining concrete C placed between the ground E of the tunnel and the centle (lining frame) 32 as shown in FIG. An example is shown. The RFID device 1 in the illustrated example also includes a holding member 10 that holds the coiled antenna 2 and the magnetic body 3 (or the conductor 4) so that the interval W is changed by the external force F, and an induced electromotive force when the antenna 2 is received. IC circuit 6 driven by The holding member 10 in the illustrated example has a fixed member 11 that is fixed against an external force at a site where a mechanical change is detected, and a movable member 12 that is locked to the fixed member 11 and that is displaced or deformed by an external force. One of the antenna 2 and the ferromagnetic material 3 (or the conductor 4) is held by the fixed member 11 and the other is held by the movable member 12.
図示例の固定部材11は、有底シリンダ状の外郭部11bと、その底面から軸心に沿って延びる軸芯部11aと、外殻部11bの開口周縁に設けた係止部11cとを含み、その軸芯部11aの底部に磁性体３（又は導電体４）を保持している。また、その軸芯部11aに遊嵌する孔付き盤状の可動部材12にアンテナ２を保持し、アンテナ２を軸芯部11aに沿って外殻部11bの内側で移動可能とし、可動部材12の軸芯部11aからの抜け出しを係止部11cで抑えている（同図（Ｃ）参照）。可動部材12とシリンダ状外郭部11bの底面との間には弾性又は塑性の変形部材13を設け、変形部材13は初期状態においてアンテナ２と磁性体３（又は導電体４）とを間隔W1だけ離して保持しているが（同図（Ａ）参照）、可動部材12が軸芯部11aの軸線方向の外力を受けて軸芯部11aに沿って底面方向に移動すると収縮し、アンテナ２と磁性体３（又は導電体４）とを間隔W2（≒０）に接近させる（同図（Ｂ）参照）。この磁性体３（又は導電体４）との接近により、上述したようにアンテナ２の送受信周波数（共振周波数）ｆがシフトすると共にその共振周波数ｆにおける振幅（電圧）が低くなり、ＲＦＩＤデバイス１を識別信号Ｓが読み取れない通信不能状態となるので、識別信号Ｓの読み取りが停止してデバイス１に加わる外力Ｆの変化を検出することができる。 The fixing member 11 in the illustrated example includes a bottomed cylindrical outer portion 11b, an axial core portion 11a extending from the bottom surface along the axial center, and a locking portion 11c provided at the opening periphery of the outer shell portion 11b. The magnetic body 3 (or the conductor 4) is held at the bottom of the shaft core portion 11a. Further, the antenna 2 is held by a plate-like movable member 12 with a hole that is loosely fitted to the shaft core portion 11a, and the antenna 2 can be moved inside the outer shell portion 11b along the shaft core portion 11a. Is prevented from coming off from the shaft core portion 11a by the locking portion 11c (see FIG. 3C). An elastic or plastic deformable member 13 is provided between the movable member 12 and the bottom surface of the cylindrical outer portion 11b, and the deformable member 13 in the initial state separates the antenna 2 and the magnetic body 3 (or conductor 4) by a distance W1. The movable member 12 is contracted when the movable member 12 receives an external force in the axial direction of the shaft core portion 11a and moves in the bottom direction along the shaft core portion 11a. The magnetic body 3 (or the conductor 4) is brought close to the interval W2 (≈0) (see FIG. 5B). By approaching the magnetic body 3 (or the conductor 4), the transmission / reception frequency (resonance frequency) f of the antenna 2 is shifted as described above, and the amplitude (voltage) at the resonance frequency f is lowered. Since the identification signal S cannot be read and communication is disabled, the reading of the identification signal S is stopped and a change in the external force F applied to the device 1 can be detected.
図２（Ｄ）に示すように、覆工コンクリートＣを打設する際に、地山Ｅの表面及びセントル32の打設面にそれぞれＲＦＩＤデバイス１を取り付け、トンネル内側（セントル32の内側）の読み出し装置20によりＲＦＩＤデバイス１からの識別信号Ｓの読み取り停止を検出することで、ＲＦＩＤデバイス１の取り付け部位ＰにおけるコンクリートＣの充填を検知する。本発明のＲＦＩＤデバイス１はコイル状アンテナにより導電率の高い媒質中でも減衰しにくい低周波数ｆで送受信するので、読み出し装置20との間に水分を含むコンクリートＣが介在する環境下でも通信が可能であり、地山Ｅの表面及びセントル32の打設面におけるコンクリートＣの充填を確実に検知することができる。同図（Ｅ）は、地山Ｅとセントル32との間の既設コンクリート34にＲＦＩＤデバイス１を取り付け、既設コンクリート34の表面におけるコンクリートＣ（新設コンクリート36）の充填を検知する実施例を示す。 As shown in FIG. 2 (D), when placing the lining concrete C, the RFID device 1 is attached to the surface of the ground E and the casting surface of the centle 32, respectively, and the inside of the tunnel (inside of the centle 32). By detecting the reading device 20 from stopping the reading of the identification signal S from the RFID device 1, the filling of the concrete C at the attachment site P of the RFID device 1 is detected. Since the RFID device 1 of the present invention transmits and receives at a low frequency f that is not easily attenuated even in a medium having high conductivity by a coiled antenna, communication is possible even in an environment where concrete C containing moisture is interposed between the reading device 20 and the RFID device 1. Yes, it is possible to reliably detect the filling of the concrete C on the surface of the natural ground E and the casting surface of the center 32. FIG. 5E shows an embodiment in which the RFID device 1 is attached to the existing concrete 34 between the natural ground E and the center 32 and the filling of the concrete C (new concrete 36) on the surface of the existing concrete 34 is detected.
図９は、既設コンクリート34と地山Ｅとの境界部におけるコンクリートＣの充填を検知するＲＦＩＤデバイス１の他の一例を示す。図示例のＲＦＩＤデバイス１の保持部材10は、直角三角形断面のシリンダ状の固定部材11と、それに遊嵌するピストン状の可動部材12とを有し、アンテナ２及び磁性体３（又は導電体４）の一方を固定部材11に保持すると共に他方を可動部材12に保持している。固定部材11の三角形断面の直交する２辺を図２（Ｄ）の地山Ｅ及び既設コンクリート34の表面にそれぞれ固定し、棒状のアンテナ２及び磁性体３（又は導電体４）の一方を三角形断面の斜辺に穿った陥没部11eの底に保持させ、その陥没部11eに移動可能に遊嵌させる可動部材12の突出部12eに他方を保持させる。 FIG. 9 shows another example of the RFID device 1 that detects the filling of the concrete C at the boundary between the existing concrete 34 and the natural ground E. The holding member 10 of the RFID device 1 in the illustrated example has a cylindrical fixed member 11 having a right-angled triangular cross section and a piston-like movable member 12 that is loosely fitted thereto, and the antenna 2 and the magnetic body 3 (or the conductor 4). ) Is held by the fixed member 11, and the other is held by the movable member 12. Two orthogonal sides of the triangular section of the fixing member 11 are fixed to the ground E and the surface of the existing concrete 34 in FIG. 2D, respectively, and one of the rod-shaped antenna 2 and the magnetic body 3 (or conductor 4) is a triangle. The other end is held by the projecting portion 12e of the movable member 12 that is held at the bottom of the depressed portion 11e that is pierced in the oblique side of the cross section and is movably fitted in the depressed portion 11e.
図９の可動部材12も、例えば固定部材11に係止部11c（図２参照）を設けることで、固定部材11に離脱しないように係止することができる。図示例では、固定部材11から離脱させずに可動部材12に棒状アンテナ２を保持させるため、固定部材11に陥没部11eに連通する挿入孔11dを穿ち、その挿入孔11dから挿入した棒状アンテナ２を可動部材12の突出部12eに保持させることができる。なお、本発明のＲＦＩＤデバイス１の通信距離はコイル状アンテナ２のコイル径Φ、ターン数（巻き数）Ｔ等により適宜に調整可能であるが、ＲＦＩＤデバイス１の通信距離に制限がある場合は、図２（Ｄ）、同図（Ｅ）又は図９に示すように取り付け向きを調節することで、読み出し装置20による識別信号Ｓの読み取り方向とアンテナ２の指向性とを一致させる効果が期待できる。 The movable member 12 in FIG. 9 can also be locked so as not to be detached from the fixed member 11 by providing a locking portion 11c (see FIG. 2) on the fixed member 11, for example. In the illustrated example, in order to hold the rod-shaped antenna 2 on the movable member 12 without detaching from the fixed member 11, the rod-shaped antenna 2 inserted through the insertion hole 11d is provided with an insertion hole 11d communicating with the recessed portion 11e. Can be held by the protrusion 12e of the movable member 12. Note that the communication distance of the RFID device 1 of the present invention can be adjusted as appropriate according to the coil diameter Φ, the number of turns (number of turns) T, etc. of the coiled antenna 2, but the communication distance of the RFID device 1 is limited. By adjusting the mounting direction as shown in FIG. 2D, FIG. 2E, or FIG. 9, an effect of matching the reading direction of the identification signal S by the reading device 20 with the directivity of the antenna 2 is expected. it can.
図７は、ＲＦＩＤデバイス１の保持部材10をシリンダ状の固定部材11とその内側に係止されて浮力により移動するピストン状の可動部材12とで構成し、その可動部材12をコンクリートＣの比重より低く且つブリージング水（浮き水）35の比重より高い比重材製とした本発明のＲＦＩＤデバイス１の実施例を示す。固定部材11及び可動部材12の一方にアンテナ２を保持させ、他方に磁性体３（又は導電体４）を保持させる。例えばコンクリートＣの充填状態を監視する場合に、コンクリートＣのうち比重の大きい骨材やセメント粒子が沈降して浮き水（ブリージング水）35と分離する現象が発生しうる。本発明のＲＦＩＤデバイス１において、アンテナ２と磁性体３（又は導電体４）との間隔Ｗがブリージング水35の圧力により変動すると、ブリージング水35の充填をコンクリートＣの充填であると誤検知するおそれがある。図７のＲＦＩＤデバイス１は、可動部材12をコンクリートの比重ρ1（≒2.4〜2.6）より低く且つブリージング水35の比重ρ2より高い比重ρの材質製（ρ2＜ρ＜ρ1）とし、コンクリートＣより低比重のブリージング水35によって可動部材12が移動することを防止し、コンクリートＣ（新設コンクリート36）の充填時にのみ可動部材12を移動させて識別信号Ｓの読み取りを停止させるので、ブリージング水35をコンクリートＣの充填である誤検知することを避けることができる。なお、可動部材12にはアンテナ２又は磁性体３（又は導電体４）が保持されるので、保持するアンテナ２又は磁性体３（又は導電体４）の比重を考慮して可動部材12の比重を決める必要がある。FIG. 7 shows that the holding member 10 of the RFID device 1 is composed of a cylindrical fixed member 11 and a piston-like movable member 12 that is locked inside and moves by buoyancy. An embodiment of the RFID device 1 of the present invention, which is made of a specific gravity material that is lower and higher than the specific gravity of breathing water (floating water) 35, is shown. The antenna 2 is held by one of the fixed member 11 and the movable member 12, and the magnetic body 3 (or the conductor 4) is held by the other. For example, when the filling state of concrete C is monitored, a phenomenon may occur in which aggregate or cement particles having a large specific gravity of concrete C settle and separate from floating water (breathing water) 35. In the RFID device 1 of the present invention, when the interval W between the antenna 2 and the magnetic body 3 (or the conductor 4) varies due to the pressure of the breathing water 35, the filling of the breathing water 35 is erroneously detected as filling of the concrete C. There is a fear. In the RFID device 1 of FIG. 7, the movable member 12 is made of a material having a specific gravity ρ lower than the specific gravity ρ1 (≈2.4 to 2.6) of concrete and higher than the specific gravity ρ2 of the breathing water 35 (ρ2 <ρ <ρ1 ). Since the movable member 12 is prevented from moving by the breathing water 35 having a specific gravity lower than that of the concrete C, and the movable member 12 is moved only when the concrete C (new concrete 36) is filled, reading of the identification signal S is stopped. It is possible to avoid erroneous detection that the breathing water 35 is filled with concrete C. Since the movable member 12 holds the antenna 2 or the magnetic body 3 (or the conductor 4), the specific gravity of the movable member 12 is considered in consideration of the specific gravity of the antenna 2 or the magnetic body 3 (or the conductor 4) to be held. It is necessary to decide.
また図８は、ブリージング水35をコンクリートＣの充填と誤検知することを避けるため、ＲＦＩＤデバイス１の保持部材10をシリンダ状の固定部材11とその内側に係止されて移動するピストン状の可動部材12とで構成し、その可動部材12をコンクリートＣ中のセメント粒子より大きく且つ細骨材より小さい網目大きさのフィルター材製とした本発明のＲＦＩＤデバイス１の実施例を示す。この場合も、固定部材11及び可動部材12の一方にアンテナ２を保持させ、他方に磁性体３（又は導電体４）を保持させる。可動部材12をコンクリートＣ中のセメント粒子の粒径（≒18μｍ、最大80〜100μｍ）より大きく且つ細骨材の粒径（10mmふるいを全部通り、５mmふるいを重量で85％以上透過する粒径）より小さい網目大きさのフィルター製とすることにより、ブリージング水35によって可動部材12が移動することを防止し、コンクリートＣ（新設コンクリート36）の充填時にのみ可動部材12を移動させて識別信号Ｓの読み取りを停止させることができる。なお、図示例ではシリンダ状の固定部材11の端面にも可動部材12と同じ網目大きさのフィルター材を設けているが、このフィルター材は省略可能である。また、可動部材12にはアンテナ２又は磁性体３（又は導電体４）が保持されるので、アンテナ２又は磁性体３（又は導電体４）に対するブリージング水35の圧力によって可動部材12が移動しないように、可動部材12の重量を適当に調整する必要がある。 Further, FIG. 8 shows a piston-like movable member in which the holding member 10 of the RFID device 1 is engaged with the cylinder-like fixing member 11 and moved inside to avoid erroneous detection of the breathing water 35 as being filled with concrete C. An embodiment of the RFID device 1 according to the present invention is shown, in which the movable member 12 is made of a filter material having a mesh size larger than cement particles in the concrete C and smaller than fine aggregate. Also in this case, the antenna 2 is held by one of the fixed member 11 and the movable member 12, and the magnetic body 3 (or the conductor 4) is held by the other. The moving member 12 is larger than the particle size of cement particles in concrete C (≒ 18μm, maximum 80-100μm) and the particle size of fine aggregates (particle size that passes through 10mm sieve and penetrates 5mm sieve by 85% or more by weight) ) By making the filter with a smaller mesh size, the movable member 12 is prevented from moving by the breathing water 35, and the movable member 12 is moved only when the concrete C (new concrete 36) is filled. Reading can be stopped. In the illustrated example, a filter material having the same mesh size as that of the movable member 12 is provided on the end face of the cylindrical fixing member 11, but this filter material can be omitted. In addition, since the movable member 12 holds the antenna 2 or the magnetic body 3 (or conductor 4), the movable member 12 does not move due to the pressure of the breathing water 35 against the antenna 2 or the magnetic body 3 (or conductor 4). Thus, it is necessary to adjust the weight of the movable member 12 appropriately.
１…ＲＦＩＤデバイス ２…コイル状アンテナ
３…磁性体 ４…導電体
５…コンデンサ ６…ＩＣ回路
７…共振回路
10…保持部材 11…固定部材
11a…軸芯部 11b…外郭部
11c…係止部 11d…挿入孔
11e…陥没部 12…稼動部
12a… 突出部 13…変形部材
14…開閉栓 15…比重材
16…フィルター材 17…蓋
20…読み出し装置 21…アンテナ
22…コンデンサ 23…共振回路
24…送受信部 25…電源部
26…ディスプレイ 27…制御部
27a…記憶手段 27b…読み出し手段
27c…読み出し停止部位検出手段 27c…表示手段
28…マルチファンクションシンセサイザー
29…デジタルオシロスコープ
30…空隙 30a…内面
31…コンクリート型枠
32…セントル 32a…打設面
33…鉄筋 34…既設コンクリート
35…ブリージング水 36…新設コンクリート
37…（沈設）構造物
40…電子タグ（ＲＦＩＤデバイス）
41…電子タグ本体 42…アンテナ
43…ＩＣ回路 44…電源回路
45…制御回路 46…記憶回路
47…送受信回路 48…カバー（止水カバー）
49…台座 49a…底部
49b…脚部 49c…間隙
49d…接着材
Ｃ…コンクリート Ｅ…地盤（地山）
Ｓ…識別信号 Ｒ…読み出し信号
Ｗ…アンテナと強磁性体との間隔DESCRIPTION OF SYMBOLS 1 ... RFID device 2 ... Coiled antenna 3 ... Magnetic body 4 ... Conductor 5 ... Capacitor 6 ... IC circuit 7 ... Resonance circuit
10 ... Holding member 11 ... Fixing member
11a ... Shaft core 11b ... Outer part
11c ... Locking part 11d ... Insertion hole
11e ... Cave part 12 ... Working part
12a… Projection 13… Deformation member
14 ... Opening / closing stopper 15 ... Specific gravity material
16 ... filter material 17 ... lid
20 ... Reading device 21 ... Antenna
22 ... Capacitor 23 ... Resonant circuit
24 ... Transceiver 25 ... Power supply
26… Display 27… Control unit
27a: Storage means 27b: Reading means
27c: Reading stop part detection means 27c: Display means
28 ... Multifunction synthesizer
29… Digital oscilloscope
30 ... Gap 30a ... Inside
31 ... Concrete formwork
32 ... Centre 32a ... Placed surface
33 ... Reinforcement 34 ... Existing concrete
35… breathing water 36… new concrete
37 ... (sink) structure
40 ... Electronic tags (RFID devices)
41… Electronic tag body 42… Antenna
43 ... IC circuit 44 ... Power supply circuit
45 ... Control circuit 46 ... Memory circuit
47 ... Transmission / reception circuit 48 ... Cover (water stop cover)
49 ... pedestal 49a ... bottom
49b ... leg 49c ... gap
49d ... Adhesive C ... Concrete E ... Ground (Mt)
S: Identification signal R: Read signal W: Distance between antenna and ferromagnetic material
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007144553AJP4905976B2 (en) | 2007-05-31 | 2007-05-31 | Frequency shift type RFID device |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007144553AJP4905976B2 (en) | 2007-05-31 | 2007-05-31 | Frequency shift type RFID device |
| Publication Number | Publication Date |
|---|---|
| JP2008298565A JP2008298565A (en) | 2008-12-11 |
| JP4905976B2true JP4905976B2 (en) | 2012-03-28 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007144553AExpired - Fee RelatedJP4905976B2 (en) | 2007-05-31 | 2007-05-31 | Frequency shift type RFID device |
| Country | Link |
|---|---|
| JP (1) | JP4905976B2 (en) |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9536122B2 (en) | 2014-11-04 | 2017-01-03 | General Electric Company | Disposable multivariable sensing devices having radio frequency based sensors |
| US9538657B2 (en) | 2012-06-29 | 2017-01-03 | General Electric Company | Resonant sensor and an associated sensing method |
| US20110320142A1 (en)* | 2010-06-28 | 2011-12-29 | General Electric Company | Temperature independent pressure sensor and associated methods thereof |
| US9658178B2 (en) | 2012-09-28 | 2017-05-23 | General Electric Company | Sensor systems for measuring an interface level in a multi-phase fluid composition |
| US10914698B2 (en) | 2006-11-16 | 2021-02-09 | General Electric Company | Sensing method and system |
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| US10598650B2 (en) | 2012-08-22 | 2020-03-24 | General Electric Company | System and method for measuring an operative condition of a machine |
| US9746452B2 (en) | 2012-08-22 | 2017-08-29 | General Electric Company | Wireless system and method for measuring an operative condition of a machine |
| US10684268B2 (en) | 2012-09-28 | 2020-06-16 | Bl Technologies, Inc. | Sensor systems for measuring an interface level in a multi-phase fluid composition |
| JP2019168231A (en)* | 2018-03-22 | 2019-10-03 | 三菱鉛筆株式会社 | Load sensor, load detection system, and load detection processor |
| CN108981975A (en)* | 2018-05-23 | 2018-12-11 | 北京航空航天大学 | A kind of pressure sensor and distribution force measuring method |
| CN110017760B (en)* | 2019-04-15 | 2024-05-10 | 同济大学 | Passive wireless displacement sensor and displacement sensing system based on helical antenna |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01259228A (en)* | 1988-04-11 | 1989-10-16 | Fuji Rubber Co Ltd | Pressure sensor |
| JPH06194275A (en)* | 1992-12-24 | 1994-07-15 | Ishikawajima Harima Heavy Ind Co Ltd | Monitor for structure |
| JP3319506B2 (en)* | 1998-06-12 | 2002-09-03 | 三菱マテリアル株式会社 | RFID element for metal body and apparatus for identifying metal body using the same |
| US6806808B1 (en)* | 1999-02-26 | 2004-10-19 | Sri International | Wireless event-recording device with identification codes |
| US7034660B2 (en)* | 1999-02-26 | 2006-04-25 | Sri International | Sensor devices for structural health monitoring |
| JP3416875B2 (en)* | 2000-07-24 | 2003-06-16 | 日本エルエスアイカード株式会社 | Civil engineering / construction structure condition inspection system and sensor-integrated device used therefor |
| JP3570512B2 (en)* | 2002-04-04 | 2004-09-29 | 三菱マテリアル株式会社 | RFID element for metal body and apparatus for identifying metal body using the same |
| JP4144004B2 (en)* | 2003-10-27 | 2008-09-03 | 株式会社Ｉｎａｘ | Water level detection device using wireless tag |
| JP2006285356A (en)* | 2005-03-31 | 2006-10-19 | Oki Electric Ind Co Ltd | Characteristic detection communication device |
| JP4350059B2 (en)* | 2005-04-19 | 2009-10-21 | 鹿島建設株式会社 | Filling confirmation method and system using electronic tag |
| SE530423C2 (en)* | 2005-04-21 | 2008-06-03 | Volvo Lastvagnar Ab | Brake pad identification system |
| JP2006309410A (en)* | 2005-04-27 | 2006-11-09 | Ohbayashi Corp | Casting status monitoring method, casting status monitoring device, casting status monitoring program, and mold form |
| Publication number | Publication date |
|---|---|
| JP2008298565A (en) | 2008-12-11 |
| Publication | Publication Date | Title |
|---|---|---|
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