JP2001127667A - Contactless identification system, interrogator and responder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interrogator and a responder with a small size, a light weight at a low cost and with a simple circuit configuration that can relax the effect of communication because the communication adopts non-modulation electromagnetic wave even when a metallic body is present in the communication area and can properly select the frequency of the communication electromagnetic wave in matching with a communication environment (such as in a factory or in an office). SOLUTION: In the contactless identification system, the interrogator 3 transmits a non-modulation electromagnetic wave with a 1st frequency to the responder 2, and the responder 2 transmits a non-modulation electromagnetic wave with a 2nd frequency different from the 1st frequency to the interrogator 3. The interrogator 3 uses a power amplifier 5 to amplify the 1st frequency and transmits the amplified signal, and the responder 2 rectifies the received frequency to obtain a DC voltage to drive an oscillation circuit 13, and the responder 2 transmits the non-modulation electromagnetic wave with this oscillating frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless identification system, an interrogator, and a transponder.

[0002]

2. Description of the Related Art A data carrier system which collects and processes information by contactlessly communicating between a transponder and an interrogator is known as a FA (Fa).
ctory Automation) field, distribution field, security field, traffic leisure field, individual information management field, livestock field, etc. With the advent of the multimedia age, this application is further expanding. With the expansion of the application, the positions of the transponders such as arrangement, installation, and attachment are various. When communicating between the transponder and the interrogator, the interrogator moves to the communicable area to the transponder, or
Conversely, whether the response device moves or both move, the communication device relatively moves to the communicable area and communicates.

[0003] While there is communication that requires a transponder (data carrier) to collect a large amount of data (information), there is also a data carrier system that detects the presence or absence of a target structure. Further, in particular, a data carrier attached to a moving object is required to be not broken by movement, impact, or the like, not to be a load (small and lightweight), and to have a shape without presence.

As a method for identifying information contained in a structure in a non-contact state using an electromagnetic wave, there are a resonance tag method, a non-contact data carrier method, and the like. The former resonance tag method is a method in which a circuit that resonates at the frequency of an electromagnetic wave signal emitted from an interrogator is provided in a transponder, and the presence thereof is sensed in a non-contact state.

[0005] On the other hand, the latter non-contact data carrier system is a system for reading and writing data (information) stored (collected) in a memory in a transponder using an electromagnetic wave signal in a certain frequency band.

[0006]

The above resonance tag method is
In terms of device manufacturing, if a resonance circuit is formed by a printed circuit, it can be mass-produced, and since it can be formed without using expensive semiconductor elements at all, it is inexpensive. However, since the resonance characteristics such as the resonance frequency and the impedance at the time of resonance of the resonance tag circuit greatly change depending on the surrounding metal environment, there is a disadvantage that the communication performance is significantly deteriorated when the metal body is close.

On the other hand, the non-contact data carrier system has a feature that the amount of identifiable data is very large because a memory is built in the data carrier. However, the semiconductor element consisting of an integrated circuit that is specially designed and manufactured is relatively expensive, the signal from the data carrier to the interrogator is weak, and data transmission is performed using a complicated modulation method. However, there is a problem that it is very weak against disturbance noise.

[0008] The present invention has been made in view of the above points,
An object of the present invention is to provide a non-contact type identification system which can be configured without using an expensive semiconductor element, has a simplified transponder, is inexpensive, and can be reduced in size.

[0009]

According to the present invention, in order to solve the above-mentioned problems, the frequency of the unmodulated electromagnetic wave from the interrogator to the transponder and the frequency of the unmodulated electromagnetic wave from the transponder to the interrogator are different. An object of the present invention is to provide a non-contact type identification system in which communication is performed using unmodulated electromagnetic waves having a frequency. An interrogator and a transponder for this system are provided.

That is, according to the non-contact type identification system of the present invention, for example, in the non-contact type identification system in which the interrogator and the transponder communicate without contact, the interrogator can recognize the object from the interrogator. Means for transmitting a non-modulated electromagnetic wave of a first frequency to a transponder to be contactless, and a transponder having received the non-modulated electromagnetic wave is a second voltage different from the first frequency by a DC voltage obtained by rectifying the non-modulated electromagnetic wave. And a means for driving an oscillation circuit that oscillates the frequency of the second frequency, and a means for returning the second frequency of the output of the oscillation circuit to the interrogator by an unmodulated electromagnetic wave.

[0011] The non-contact type identification system according to the present invention is described in claim 2.
For example, in the non-contact data carrier communication system in which the interrogator and the transponder communicate without contact, the first frequency unmodulated electromagnetic wave is transmitted from the interrogator to the target transponder in a non-contact manner, as described in Means for receiving the unmodulated electromagnetic wave, the responder drives an oscillation circuit that oscillates a second frequency different from the first frequency with a DC voltage obtained by rectifying the unmodulated electromagnetic wave, 30KH frequency
300KHz long wave band, 300KHz-3MHz
Means for transmitting at a frequency in one frequency band out of a medium wave band and a short wave band of 3 MHz to 30 MHz, and transmitting the second frequency at a frequency in a different frequency band.

According to a third aspect of the present invention, there is provided an interrogator for oscillating a first frequency corresponding to, for example, a transponder to be processed, and an unmodulated electromagnetic wave obtained by amplifying an output of the oscillating circuit. Transmitting means for transmitting via an antenna,
It comprises means for receiving an unmodulated electromagnetic wave of the second frequency from the transponder responded by the transmitting means via the antenna and performing heterodyne detection, and means for comparing the detected output with a reference value and displaying the result.

According to a fourth aspect of the present invention, there is provided a transponder for receiving a signal wave transmitted at a predetermined first frequency, for example, and receiving the signal wave at the predetermined frequency. A rectifier circuit that rectifies the signal wave and outputs a DC voltage; an oscillator that oscillates a predetermined second frequency by being supplied with a DC voltage from the rectifier circuit; A transmission antenna circuit for transmitting a frequency.

[0014]

Next, an embodiment of the non-contact type identification system of the present invention will be described with reference to the drawings. First, the configuration of the non-contact type identification method will be specifically described.

FIG. 1 is a circuit diagram for explaining a non-contact type identification system. The non-contact type identification method 1 includes a transponder 2
And the interrogator 3. The interrogator 3 and the transponder 2 communicate non-modulated electromagnetic waves in a non-contact manner. This communication means is, for example, of the electromagnetic induction type (induction electromagnetic field) shown in FIG.

This electromagnetic induction system is shown in FIG. 2, and the transmitting and receiving antennas of the interrogator 3 and the transponder 2 are used for the loop coils 31 or the air-core coils 32 or for the loop-shaped coil 31 and the air-core coil 32. By combination, non-modulated electromagnetic waves are communicated using an induction electromagnetic field as a transmission medium. FIG. 2 shows the latter combination of the loop-shaped coil 31 and the air-core coil 32.

That is, in this example, the loop coil 31 is configured as a transmitting antenna of the interrogator 4 and the air core coil 32 is configured as a receiving antenna of the transponder 2. The distance between these antennas is a communication distance of about several tens cm to about 2 m. This method has a feature that it is not affected by rain, ice, dust, iron powder, magnetism, oil, and the like. The directivity of the antenna is slow and the communication range is wide. further,
The size of the antenna can be designed to any size. It has features such as.

First, the configuration of the interrogator 3 will be described. For the transponder 2 to be called, a predetermined first
An oscillation circuit (DSS module) 4 for outputting an AC signal having a frequency of, for example, 60 KHz is provided. The number of transponders 2 having the same frequency may be one, plural, or many. In the case of various types of transponders, an oscillator having a corresponding assigned frequency is prepared. In this embodiment, only one type is used.

It is characterized in that the output of the selected oscillation circuit 4 is transmitted without modulation. That is, the power amplifier 5 is connected to the output circuit of the oscillation circuit 4 to transmit sufficient power. The output circuit of the power amplifier 5 is connected to a transmission antenna circuit 6 that resonates at the first frequency, for example, a series resonance circuit of a coil antenna having 100 turns and a capacitor, thereby forming a transmission system of the interrogator. .

On the other hand, the receiving system of the interrogator is provided with a receiving antenna circuit 7 for receiving the electromagnetic wave of the second frequency transmitted from the transponder 2, for example, a mesh antenna having a hole of 2 mm to 7 mm square. I have.

The output circuit of the receiving antenna circuit 7 includes:
A receiver 8, for example a superheterodyne receiver, is connected via an amplifier for amplifying to the desired value. The output received by the receiver 8 and subjected to superheterodyne detection is supplied to a comparator 9. The comparator 9 compares it with a predetermined reference value, and if it is equal to or more than the reference value, sounds a display, for example, a buzzer 10 to indicate that it is the predetermined transponder 2. Thus, the interrogator 3 is configured.

Next, the configuration of the transponder 2 will be described. A receiving antenna circuit 11 for receiving an unmodulated electromagnetic wave of the first frequency transmitted from the interrogator 3;
A reticulated antenna having a mm-square hole is provided. The output circuit of the receiving antenna circuit 11 is connected to a rectifier circuit 12 for rectifying the received unmodulated electromagnetic wave, for example, a voltage doubler rectifier circuit. The output circuit of the rectifier circuit 12 uses the rectified DC voltage as a power source to set the second
The oscillation circuit 13 which oscillates at the frequency of is connected.

It is characterized in that the output of the oscillation circuit 13 is returned to the interrogator 3 as an unmodulated electromagnetic wave. The output circuit of the oscillation circuit 13 is connected to a transmission antenna circuit 14 for transmitting the second frequency to the interrogator 3, for example, a series resonance circuit of a coil antenna and a capacitor. Thus, the transponder 2 is configured.

The communication operation of the data carrier system 1 configured as described above will be described below. That is, a desired transponder 2 is called from the interrogator 3.

That is, the oscillation circuit 4 oscillates a first frequency, for example, 60 KHz, which is a desired set frequency of the transponder 2. This oscillation frequency is transmitted as an unmodulated electromagnetic wave.
That is, the first frequency is amplified by the power amplifier 5,
The transmission is performed from the transmission antenna circuit 6. When the corresponding transponder 2 existing in the transmission area of the transmission antenna circuit 6 exists,
The transponder 2 has a receiving antenna circuit 11 having a resonance characteristic at a transmission wave of 60 KHz, and receives this.

The signal wave received by the antenna circuit 11 is rectified by the rectifier circuit 12 to obtain a DC voltage at the output. In this embodiment, the oscillation circuit 13 is a voltage doubler rectifier circuit.
Output a DC voltage sufficient to drive the. This DC voltage is supplied to the oscillating circuit 13 to cause the oscillating circuit 13 to oscillate as a power supply. (The output of the power amplifier of the interrogator 3 is selected so that the power of the oscillation output is sufficient to be received by the interrogator 3.) That is, the oscillation frequency is the first frequency 60K.
A second frequency different from 10 Hz to 10 MHz to 100 MHz, for example, 80 MHz is oscillated. This oscillation output is returned to the interrogator 3 from the transmission antenna circuit 14 as an unmodulated electromagnetic wave.
This unmodulated electromagnetic wave is received by the receiving antenna circuit 7 of the interrogator 3. This received signal wave is superheterodyne detected by a superheterodyne receiver 8 having a center frequency of 4 MHz. This detection output is supplied to a comparator 9 and compared with a reference value.
Drive and sound.

In this way, the interrogator 3 can recognize (identify) the existence of the responder 2. The display means is not limited to a buzzer, and may have a light display, for example, an LED if it has a display function.
May be turned on, or both sound and light may be displayed.

In this communication method, a frequency different from the frequency of the electromagnetic wave transmitted from the interrogator 3 to the transponder 2 and the frequency of the electromagnetic wave returned from the transponder 2 to the interrogator 3 are selected, Is to communicate. By this means, both the interrogator 3 and the transponder 2 are relatively expensive, the design technique is advanced, and the modulator, demodulator,
Since a circuit such as a data (information) memory and a sensor is not required, the circuit configuration is simple, small, and inexpensive.

Furthermore, since the resonance characteristics and communication performance of the antenna circuit in the transponder are not closely related, even if there is a metal body in the periphery, the influence is smaller than that of the resonance tag system. It is greatly eased.

Furthermore, since transmission / reception is performed using an unmodulated wave, communication disturbance due to disturbance noise can be suppressed as compared with a communication system using a modulated wave.

Further, the frequencies of the first and second electromagnetic waves can be appropriately changed according to the use environment.

Further, highly reliable communication is possible due to the above effects.

In a specific embodiment of the above communication, the frequency band of the electromagnetic wave is set to a long wave band of 30 KH to 300 KHz,
0KHz to 3MHz medium wave band, 3MHz to 30MH
Divide the selected frequency into z shortwave bands. And the first
In the case where a frequency within one frequency band is selected from among the above frequency bands, the second frequency is to select a frequency within a different frequency band.

The frequency band is not limited to the above-mentioned frequency band, and a frequency at which no induction or beat occurs between the frequency transmitted from the interrogator 3 to the transponder 2 and the frequency transmitted from the transponder 2 to the interrogator 3 is selected. Then, each may be selected within the same band. For example, from the interrogator 3 to the responder 2 in the long wave band
And the frequency transmitted from the transponder 2 to the interrogator 3 may be selected.

The frequency transmitted from the interrogator 3 to the transponder 2 is mainly for transmitting power for driving the transmission circuit of the transponder 2, and therefore has a longer wavelength with a relatively large power, that is, a longer wavelength. Low frequencies are relatively effective.

Further, as for the frequency to be transmitted from the transponder 2 to the interrogator 3, a relatively high frequency having a short wavelength is effective in order to transmit effectively with small power. That is, the short wave band is effective.

Further, the frequency transmitted from the transponder 2 to the interrogator 3 may need to take measures against noise generated from electrical equipment. As this means, it is possible to take measures against external noise by selecting a frequency of the electromagnetic wave of 1 MHz or more. This has been found by analyzing frequency components from peripheral electronic devices and the like that actually exist in the communication environment.

That is, the frequency component of 1 MHz or more was extremely small or absent.

Embodiment In order to set the output electric field strength of the interrogator 3 high while complying with the Radio Law, the frequency of the electromagnetic wave transmitted from the interrogator 3 is set to, for example, 125 KHz, and the frequency of the electromagnetic wave transmitted from the transponder 2 is set to 1
Transmit at frequencies above MHz. As a result, stable communication was achieved without being affected by disturbance noise.

In this non-contact type identification method, for example, in a can juice production line, the above-mentioned transponder 2 is attached to all can juices of a desired type, and the transponder 2 is arranged in a can juice line flowing through a belt line. If this method is applied to select only a desired can juice, the system can be configured inexpensively and in a small size.

Further, by applying the present system to the management of books in a library, management of unauthorized removal of books can be executed. That is, the transponder 2 is attached to each book,
By unifying the entrance and exit of the viewer, management becomes possible. That is, the interrogator 3 is set at the entrance, and every time a viewer comes out, the interrogator 3 sends the first
By transmitting the transmission frequency, the non-procedure of the designated book can be automatically managed.

[0042]

As described above, according to the present invention,
The circuit configuration is simple, compact, lightweight, and inexpensive.

Further, since the resonance characteristics and the communication performance of the antenna circuit in the transponder are not closely related, even if a metal body is present in the vicinity, there is no significant influence unlike the resonance tag system. .

Further, in order to transmit and receive using unmodulated electromagnetic waves,
Communication disturbance due to disturbance noise can be suppressed as compared with a communication system using modulated electromagnetic waves.

Further, the frequency of the communication electromagnetic wave can be appropriately selected according to the communication environment (in a factory, in an office, etc.).

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a data carrier system for explaining an embodiment of the present invention.

FIG. 2 is a circuit connection diagram for explaining an embodiment of the communication method of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Contactless identification system 2 ... Transponder, 3 ... Interrogator, 4, 13 ... Oscillation circuit, 5 ... Power amplifier, 6, 14 ... Transmission antenna circuit, 7, 11 ... Receiving antenna circuit, 8 ... Receiver 9: comparator, 10: buzzer, 12: rectifier circuit, 31: loop coil, 32: air-core coil,

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiichi Kobayashi 5-14-25 Ryoke, Kawaguchi City, Saitama Prefecture Inside the Kawaguchi Plant of Toshiba Chemical Co., Ltd. (72) Yutaka Yoshinari 5-14-25 Ryoke, Kawaguchi City, Saitama Prefecture No. Toshiba Chemical Corporation Kawaguchi Plant (72) Inventor Yasutaka Nakazaki 1-16-1 Yurioka, Aso-ku, Kawasaki City, Kanagawa Prefecture 2 International Business Connections, Inc. (72) Inventor Hideo Tamura 1, Yurioka Aso-ku, Kawasaki City, Kanagawa Prefecture 16-chome 2 International Business Connections F-term (reference) 5K012 AB03 AB05 AC06 AC08 AC10 BA06

Claims (4)

[Claims] 1. A non-contact type identification method in which an interrogator and a transponder contactlessly communicate with each other, wherein a means for non-contact transmission of an unmodulated electromagnetic wave of a first frequency from the interrogator to a transponder of interest. A transponder that receives the unmodulated electromagnetic wave drives a oscillating circuit that oscillates a second frequency different from the first frequency with a DC voltage obtained by rectifying the unmodulated electromagnetic wave; And a means for returning the frequency to the interrogator by an unmodulated electromagnetic wave. 2. A non-contact type identification system in which an interrogator and a transponder contactlessly communicate with each other, means for non-contact transmission of an unmodulated electromagnetic wave of a first frequency from the interrogator to a transponder of interest. A transponder that receives the unmodulated electromagnetic wave drives a oscillating circuit that oscillates a second frequency different from the first frequency with a DC voltage obtained by rectifying the unmodulated electromagnetic wave, and sets the first frequency to 30 KH to 30 KH. Means for transmitting at a frequency within one frequency band of a long wave band of 300 kHz, a medium wave band of 300 kHz to 3 MHz, and a short wave band of 3 MHz to 30 MHz, the second frequency is transmitted at a frequency within a different frequency band; A non-contact type identification method characterized by comprising: 3. An oscillating circuit for oscillating a first frequency corresponding to a transponder of interest, transmitting means for transmitting an unmodulated electromagnetic wave obtained by amplifying an output of the oscillating circuit via an antenna, and responding by the transmitting means. An interrogator comprising: means for receiving an unmodulated electromagnetic wave of a second frequency from a transponder via an antenna to perform heterodyne detection; and means for comparing the detected output with a reference value and displaying the result. 4. A receiving antenna circuit for receiving a signal wave transmitted at a predetermined first frequency, a rectifying circuit for rectifying the signal wave received by the receiving antenna circuit and outputting a DC voltage, An oscillator that oscillates a predetermined second frequency when a DC voltage is supplied from a rectifier circuit, and a transmission antenna circuit that transmits a second frequency of the output of the oscillator. And transponder.