JP2005182614A - Method and device for evaluating reader/writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a method and a device for evaluating reader/writer, which efficiently evaluate whether a non-contact reader/writer can communicate with a portable recording medium at a prescribed communication distance or not. <P>SOLUTION: A reader/writer evaluation device 1 is provided with; an antenna coil L2; a tuning capacitor C1 for generating a tuning frequency together with the antenna coil L2; a DC conversion means 11 which converts an induced electromotive force induced in the antenna coil L2 in the reader/writer evaluation device 1 by a magnetic field generated from the antenna coil L1 of a non-contact reader/writer 2, to a DC after causing the force to pass a tuning circuit 12 comprising the antenna coil L2 and the tuning capacitor C1; and a discrimination means U1 which compares a DC voltage obtained by the DC conversion means 11 with a voltage Vref required to operate an IC chip in the portable recording medium, to discriminate whether the non-contact reader/writer 2 being an evaluation object can communicate with the portable recording medium or not. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a reader / writer evaluation apparatus and method for evaluating whether or not a non-contact type reader / writer can communicate with a portable recording medium at a predetermined communication distance.

  Usually, communication between a non-contact type reader / writer or a non-contact type reader / writer module (hereinafter simply referred to as “non-contact type reader / writer”) and a non-contact type portable recording medium is provided for each antenna. This is realized by using an electromagnetic induction phenomenon via a coil. Non-contact type portable recording media (so-called RFID) include IC cards and IC tags, and in any case, an IC chip is provided inside.

  Communication is possible when the tuning frequency determined by the inductance of the antenna coil in the portable recording medium and the tuning capacity of the tuning capacitor is tuned to the carrier frequency used during communication. Furthermore, a portable recording medium that does not have an IC chip driving power source must be supplied with necessary power from a non-contact type reader / writer via an antenna coil (for example, see Patent Document 1).

  In this way, since non-contact communication (and power supply) is performed between the non-contact type reader / writer and the portable recording medium, a communicable range (hereinafter referred to as “maximum communication distance”) is established between them. Exists.

  Since communication exceeding the maximum communication distance is impossible, it is possible to determine whether or not communication is possible with a predetermined communication distance with respect to a portable recording medium at the time of trial production or manufacture of the non-contact type reader / writer. Need to be evaluated. As an example, if the maximum communication distance is 10 cm, three points of 0 cm, 5 cm, and 10 cm are set as evaluation points, and an evaluation test of the non-contact type reader / writer is performed.

Japanese Patent Laid-Open No. 11-45319

  The conventional method for evaluating a non-contact type reader / writer reproduces a series of procedures for actually communicating with a portable recording medium, that is, transmission / reception of various commands on the non-contact type reader / writer to be evaluated. There is a problem that it is necessary to evaluate a transmission / reception result, which takes time and effort.

  In addition, as described above, it is necessary to evaluate whether or not the non-contact type reader / writer can normally communicate at a plurality of communication distances within the maximum communication distance (for example, 0 cm, 5 cm, and 10 cm). A non-contact type reader / writer evaluation device having a mechanism is required. Specifically, there is a need for a mechanism that allows the non-contact type reader / writer to be fixed to the evaluation apparatus with a predetermined communication distance, and that the interval can be set for a plurality of communication distances. There is a problem that such a mechanism is large and complicated.

The above problem can be a particularly serious problem during the manufacturing stage where a large number of contactless reader / writers must be evaluated efficiently.
Accordingly, in view of the above problems, an object of the present invention is to provide a reader / writer evaluation apparatus and method for simply and efficiently evaluating whether or not a non-contact type reader / writer can communicate with a portable recording medium at a predetermined communication distance. It is to provide.

  In order to achieve the above object, in the present invention, a non-contact type reader / writer to be evaluated operates an IC chip in a portable recording medium with respect to a reader / writer evaluation device separated by a predetermined communication distance. By determining whether or not it is possible to supply the power necessary for this, it is evaluated whether or not the non-contact type reader / writer can communicate with the portable recording medium at a predetermined communication distance. The portable recording medium includes an IC card and an IC tag.

  Generally, the communicable range between the non-contact type reader / writer and the portable recording medium is such that the electromotive force induced in the antenna coil on the portable recording medium side by the magnetic field generated from the antenna coil on the non-contact type reader / writer side is It is determined by whether or not it is sufficient as a power source necessary for operating the IC chip in the portable recording medium.

  More specifically, in the reader / writer evaluation apparatus according to the present invention, similarly to the configuration of the portable recording medium, an antenna coil and a tuning capacitor constituting a tuning circuit are provided inside the antenna coil. When the non-contact type reader / writer to be evaluated is arranged away from the reader / writer evaluation device by a predetermined communication distance, the antenna coil in the reader / writer evaluation device is caused by the magnetic field generated from the antenna coil in the non-contact type reader / writer. Whether the induced electromotive force can be a power source necessary for operating the IC chip in the portable recording medium when the non-contact type reader / writer communicates with the portable recording medium at the communication distance. judge. If it can be confirmed that the electromotive force induced in the antenna coil in the reader / writer evaluation apparatus is greater than or equal to a predetermined value, it can be determined that the non-contact type reader / writer can communicate with the portable recording medium at the communication distance.

More specifically, the reader / writer evaluation apparatus according to the present invention is:
An antenna coil;
A tuning capacitor constituting a tuning frequency with the antenna coil;
DC conversion means for converting an induced electromotive force induced in the antenna coil in the reader / writer evaluation apparatus by a magnetic field generated from the antenna coil of the non-contact type reader / writer through a tuning circuit including the antenna coil and a tuning capacitor and then converting the DC into DC. ,
The non-contact reader / writer to be evaluated can communicate with the portable recording medium by comparing the direct current voltage obtained by the direct current conversion means with the voltage necessary for operating the IC chip in the portable recording medium. Determining means for determining whether or not there is.

  In addition, the reader / writer evaluation apparatus according to the present invention described above does not evaluate a non-contact type reader / writer at a predetermined communication distance used for actual communication with a portable recording medium. The non-contact type reader / writer may be evaluated at different distances.

That is, the reader / writer evaluation apparatus according to the present invention is:
When the non-contact type reader / writer to be evaluated is installed at a distance different from the predetermined communication distance, an induced electromotive force of the same magnitude as that at the predetermined communication distance is applied to the antenna coil. Inductance changing means for changing the inductance of the antenna coil so as to induce;
There may be further provided tuning capacity changing means for changing the tuning capacity of the tuning capacitor in conjunction with the change of the inductance changing means so as to configure the tuning frequency with the antenna coil whose inductance has been changed.

  According to the present invention, it is possible to easily and efficiently evaluate whether or not a non-contact type reader / writer can communicate with a portable recording medium at a predetermined communication distance. Ideal for evaluation of contact type reader / writer. In particular, the reader / writer evaluation apparatus according to the present invention does not evaluate a non-contact type reader / writer at a predetermined communication distance used for actual communication with a portable recording medium, but is different from the predetermined communication distance. Thus, the reader / writer evaluation device can be further downsized if it is configured so that the non-contact type reader / writer can be evaluated.

  FIG. 1 is a circuit diagram of a reader / writer evaluation apparatus according to a first embodiment of the present invention. Hereinafter, the same reference numerals in different drawings mean the same components.

  The reader / writer evaluation apparatus 1 for evaluating whether or not the non-contact type reader / writer 2 can communicate with a portable recording medium at a predetermined communication distance according to the first embodiment of the present invention includes an antenna coil L2 and a tuning function. Capacitor C1, DC conversion means 11, and determination means U1 are provided.

  The tuning capacitor C1 is included in the tuning circuit 12 that forms a tuning frequency together with the antenna coil L2.

  The DC conversion means 11 includes a diode D1 and a smoothing capacitor C2. The DC conversion means 11 is a tuning circuit comprising an antenna coil L2 and a tuning capacitor C1. The induced electromotive force induced in the antenna coil L2 in the reader / writer evaluation apparatus 1 by a magnetic field generated from the antenna coil L1 of the non-contact type reader / writer 2 After passing through 12, DC conversion is performed.

  The determination unit U1 compares the DC voltage obtained by the DC conversion unit 11 with the voltage Vref necessary for operating the IC chip in the portable recording medium, and the non-contact type reader / writer 2 to be evaluated It is determined whether or not communication with a portable recording medium is possible.

  The reader / writer evaluation apparatus 1 according to the first embodiment of the present invention can be said to be a pseudo portable recording medium (RFID) when viewed from the non-contact type reader / writer 2 to be evaluated. Therefore, in order to make the reader / writer evaluation apparatus 1 equivalent to a portable recording medium for the non-contact type reader / writer 2 to be evaluated, it corresponds to a load such as an IC chip in the portable recording medium. A resistor R1 is provided.

Next, the operation of the present invention will be described.
In FIG. 1, the antenna coil L2 in the reader / writer evaluation apparatus 1 is induced by the magnetic field generated from the antenna coil L1 in the non-contact type reader / writer 2 to be evaluated, and an induced electromotive force is generated. This induced electromotive force passes through the tuning circuit 12, and is then rectified by the diode D1 which is the DC conversion means 11, and is smoothed by the smoothing capacitor C2, thereby generating a DC voltage.

  In the determination unit U1, a reference voltage Vref set to be equal to or higher than a voltage necessary for operating the IC chip in the portable recording medium is set in advance. The determination unit U1 compares the DC voltage generated by the DC conversion unit 11 with the reference voltage Vref. If the DC voltage generated by the DC converter 11 is equal to or higher than the reference voltage Vref, it is determined that the non-contact type reader / writer 2 can communicate normally. The evaluation result is preferably shown on a light emitting means such as an LED, an acoustic means such as a buzzer, or a display means such as a computer display screen.

FIG. 2 is a circuit diagram of a reader / writer evaluation apparatus according to a second embodiment of the present invention.
The second embodiment of the present invention does not evaluate the non-contact type reader / writer at a predetermined communication distance used for actual communication with the portable recording medium as in the first embodiment. The non-contact type reader / writer can be evaluated at a distance different from the communication distance.

  As shown in FIG. 2, the reader / writer evaluation apparatus 1 according to the second embodiment of the present invention is the same as the reader / writer evaluation apparatus 1 according to the first embodiment described with reference to FIG. Tuning capacity changing means S2.

  The inductance changing means S1 has the same size as that when the non-contact type reader / writer 2 to be evaluated is installed away from the predetermined communication distance by a distance different from the predetermined communication distance. The inductance of the antenna coil L2 is changed so as to induce the induced electromotive force to the antenna coil L2.

  The tuning capacity changing means S2 changes the tuning capacity of the tuning capacitor C1 in conjunction with the changing operation of the inductance changing means S1 so as to configure the tuning frequency with the antenna coil L2 whose inductance has been changed. In FIG. 2, the change of the tuning capacitance of the tuning capacitor C1 is schematically represented by whether or not the capacitor C3 is turned on.

Generally, in order to maximize the induced power in the portable recording medium by the magnetic field generated by the antenna coil in the non-contact type reader / writer, it is necessary to maximize the effective flux linkage. The antenna radius of the antenna coil L1 of the non-contact type reader / writer 2 is a ₁ , the antenna coil L2 of the antenna coil L2 of the reader / writer evaluation apparatus 1 is a ₂ , and the ratio of the number of turns between the antenna coil L1 and the antenna coil L2 is “1: n”, the distance between the antenna coil L1 of the non-contact type reader / writer 2 and the antenna coil L2 of the reader / writer evaluation device 1 is z, and the reader / writer evaluation device with respect to the antenna axis of the antenna coil L1 of the non-contact type reader / writer 2 Assuming that the inclination of one antenna coil L2 is θ and the current is I, the flux linkage Φ is expressed by the following equation.

Therefore, the induced electromotive force induced in the antenna coil L2 in the reader / writer evaluation apparatus 1 by the magnetic field generated from the antenna coil L1 of the non-contact type reader / writer 2 is inversely proportional to “(a ₁ ² + z ² ) ^3/2 ”. , N or a ₂ ² .

Therefore, an electromotive force equivalent to the electromotive force W induced in the antenna coil L2 when the antenna coil L1 and the antenna coil L2 are separated from each other by the distance z is expressed as a distance between the antenna coil L1 and the antenna coil L2. for but obtained if less than the distance z may be reduced to or antenna radius a ₂ to reduce the number of turns n of the antenna coil L2, also, the distance between the antenna coil L1 and the antenna coil L2 In order to obtain when the distance is longer than the distance z, the number n of turns of the antenna coil L2 may be increased or the antenna radius a ₂ may be increased. The inductance changing means S1 in the second embodiment of the present invention changes the number of turns or the antenna radius of the antenna coil L2 of the reader / writer evaluation apparatus 1.

  When the inductance of the antenna coil L2 of the reader / writer evaluation device 1 is changed, the tuning capacity of the tuning capacitor must also be changed in order to maintain the tuning frequency. The tuning frequency is defined by 1 / 2π√ (LC) where L is the inductance of the antenna coil and C is the tuning capacity of the tuning capacitor. In the second embodiment of the present invention, the tuning capacitance changing means S2 adjusts the tuning capacitance of the tuning capacitor C1 in conjunction with the changing operation of the inductance changing means S1 so as to configure the tuning frequency with the antenna coil L2 whose inductance is changed. change.

  FIG. 3 is a circuit diagram showing a specific example of inductance changing means and tuning capacity changing means in the reader / writer evaluation apparatus according to the second embodiment of the present invention.

  As shown in FIG. 3, the antenna coil L2 in the reader / writer evaluation apparatus 1 in FIG. 2 changes the number of turns of the antenna coil L2 every time the connection destination of the inductance changing unit S1 is switched.

  Also, the capacitances of the tuning capacitors C1-a, C1-b, C1-c and C1-d connected to the tuning capacitance changing means S2 are different from each other. Therefore, by switching the connection destination of the tuning capacitance changing means S2, The connected tuning capacity is changed. The capacitances of the tuning capacitors C1-a, C1-b, C1-c and C1-d are determined so that the tuning capacitance of the tuning capacitor corresponding to the change in the number of turns of the antenna coil L2 by the inductance changing means S1 is selected. Keep it.

  In FIG. 3, the number of connection destinations to the antenna coil L2 and the number of tuning capacitors are examples, and may be numbers other than those shown in FIG.

  4A and 4B are diagrams showing another specific example of the inductance changing means in the reader / writer evaluation apparatus according to the second embodiment of the present invention, where FIG. 4A is a perspective view and FIG. 4B is a front view.

  In this specific example, as shown in FIG. 4, the antenna coil L2 in the reader / writer evaluation apparatus 1 in FIG. 2 changes the antenna radius of the antenna coil L2 every time the connection destination of the inductance changing means S1 is switched.

  In the reader / writer evaluation apparatus 1, antenna coils L2-a, L2-b, L2-c, and L2-d having different antenna radii are provided on the disc 21. The disc 21 is rotatable about a rotation axis 22 and is set so that an antenna coil having a desired antenna radius faces the non-contact type reader / writer 2 to be evaluated. The rotating shaft 22 may be rotated by a motor (not shown) or manually rotated. On the disk 21, a determination circuit 23 including a direct current conversion unit 11, a tuning circuit 12, a resistor R1, and a determination unit U1 and an inductance changing unit S1 are provided. The inductance changing unit S1 switches the connection destination to the antenna coil facing the non-contact type reader / writer 2 to be evaluated. As already described, the tuning capacitance changing means S2 uses the tuning capacity of the tuning capacitor C1 in the tuning circuit 12 as the changing operation of the inductance changing means S1 so as to configure the tuning frequency with the antenna coil whose inductance has been changed. Change in conjunction.

  In FIG. 4, the number of antenna coils is an example, and may be a number other than that shown in FIG. 4.

  Further, the inductance changing means S1 may be capable of simultaneously changing both the number of turns of the antenna coil L2 and the antenna radius of the reader / writer evaluation apparatus 1, and may be realized by combining, for example, the structures shown in FIGS. .

  As described above, according to the second embodiment of the present invention, the non-contact type reader / writer is evaluated at a predetermined communication distance used for actual communication with the portable recording medium as in the first embodiment. Instead, since the contactless reader / writer can be evaluated at a distance shorter than the predetermined communication distance, the reader / writer evaluation apparatus can be further downsized.

  The reader / writer evaluation apparatus according to the present invention can also be applied as an evaluation apparatus for an IC tag having a self-power supply.

  Used for an evaluation device that evaluates a non-contact type reader / writer as to whether or not it can communicate with a portable recording medium at a predetermined communication distance, that is, when it is prototyped or manufactured. Is possible. Further, the present invention can be applied as an evaluation apparatus that performs the same evaluation on an IC tag having a self-power supply.

1 is a circuit diagram of a reader / writer evaluation apparatus according to a first embodiment of the present invention. FIG. It is a circuit diagram of the reader / writer evaluation apparatus by 2nd Example of this invention. It is a circuit diagram which shows one specific example of the inductance change means and tuning capacity | capacitance change means in the reader / writer evaluation apparatus by 2nd Example of this invention. It is a figure which shows another specific example of the inductance change means in the reader / writer evaluation apparatus by 2nd Example of this invention, (a) is a perspective view, (b) is a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reader / writer evaluation apparatus 2 ... Non-contact type reader / writer 11 ... DC converter 12 ... Tuning circuit 21 ... Disk 22 ... Rotating shaft 23 ... Judgment circuit C1, C1-a, C1-b, C1-c, C1- d, C3 ... tuning capacitor C2 ... smoothing capacitor D1 ... diode L1 ... antenna coil L2 of non-contact type reader / writer ... antenna coil R1 ... resistor U1 ... judgment means

Claims (8)

A reader / writer evaluation device that evaluates whether or not a non-contact type reader / writer can communicate with a portable recording medium at a predetermined communication distance,
An antenna coil;
A tuning capacitor that forms a tuning frequency with the antenna coil;
DC conversion means for converting the induced electromotive force induced in the antenna coil by the magnetic field generated from the antenna coil for the non-contact type reader / writer through a tuning circuit including the antenna coil and the tuning capacitor, and then converting the DC into DC.
The non-contact type reader / writer to be evaluated communicates with the portable recording medium by comparing the DC voltage obtained by the DC converting means with the voltage necessary for operating the IC chip in the portable recording medium. A reader / writer evaluation apparatus comprising: a determination unit that determines whether or not it is possible. When the non-contact type reader / writer to be evaluated is installed at a distance different from the predetermined communication distance, an induced electromotive force having the same magnitude as that at the predetermined communication distance is provided. Inductance changing means for changing the inductance of the antenna coil so as to be guided to the antenna coil;
The tuning capacitance changing means for changing the tuning capacity of the tuning capacitor in conjunction with the change of the inductance changing means so as to form a tuning frequency with the antenna coil whose inductance has been changed. Reader / writer evaluation device.   The reader / writer evaluation apparatus according to claim 2, wherein the inductance changing unit includes a turn number changing unit that changes the inductance of the antenna coil by changing the number of turns of the antenna coil.   4. The reader / writer evaluation apparatus according to claim 2, wherein the inductance changing unit includes a radius changing unit that changes an antenna radius of the antenna coil to change an inductance of the antenna coil. A reader / writer evaluation method for evaluating whether a non-contact type reader / writer can communicate with a portable recording medium at a predetermined communication distance using a reader / writer evaluation device,
A tuning circuit comprising the antenna coil and a tuning capacitor that constitutes a tuning frequency with respect to the induced electromotive force induced in the antenna coil in the reader / writer evaluation device by the magnetic field generated from the antenna coil for the non-contact type reader / writer A DC conversion step for DC conversion after passing through,
The non-contact type reader / writer to be evaluated communicates with the portable recording medium by comparing the direct current voltage obtained by the direct current conversion step with the voltage necessary for operating the IC chip in the portable recording medium. A reader / writer evaluation method comprising: a determination step of determining whether or not it is possible. The same as when the non-contact type reader / writer to be evaluated is set apart from the predetermined communication distance when the non-contact type reader / writer is set apart from the predetermined communication distance with respect to the reader / writer evaluation apparatus. An inductance changing step of changing the inductance of the antenna coil so as to induce an induced electromotive force of a magnitude to the antenna coil in the reader / writer evaluation device;
The tuning capacitance changing step of changing the tuning capacitance of the tuning capacitor in conjunction with the change of the inductance changing step so as to configure a tuning frequency with the antenna coil whose inductance has been changed. Reader / writer evaluation method.   The reader / writer evaluation method according to claim 6, further comprising a turn number changing step of selecting a desired inductance of the antenna coil by changing the number of turns of the antenna coil. The reader / writer evaluation method according to claim 6, further comprising a radius changing step of selecting a desired inductance of the antenna coil by changing an antenna radius of the antenna coil.

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