JPH0894744A - Transponder without power supply - Google Patents

Abstract

PURPOSE: To improve the speed of identification by providing a rectifying power supply circuit, wherein the input of the electromagnetic wave received with an antenna is made to be a power supply, an oscillating circuit, which generates the frequency of the difference of the electromagnetic wave for transmitting the received electromagnetic wave, and a cross modulation circuit. CONSTITUTION: A rectifying-power-supply/cross-modulation circuit 3 includes a rectifying circuit, which rectifies the input of the electromagnetic wave received with an antenna, obtains the DC power and supplies the power into an oscillating circuit 4 and others, and comprises a cross modulation circuit, which generates the transmitting frequency by cross modulation based on the oscillated output of the circuit 4 and the input of the electromagnetic wave received with the antenna 1. The received electromagnetic wave outputted from the circuit 3 is demodulated with a demodulation control circuit 5, and identified information is stored in a memory 6. The identification number of the identified information stored in the memory 6 is outputted as the modulating signal by the input of the received electromagnetic wave and inputted into the circuit 4. The frequency of the difference of the receiving and transmitting frequencies is modulated with the transmitting identification number. The modulated wave and the received electromagnetic wave are inputted into the circuit 3, and the transmitting electromagnetic wave by the cross modulation is generated and transmitted from the antenna 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous transmission / reception type powerless transponder, and more particularly to a powerless transponder in which a transmission frequency of a response signal depends on a frequency of an electromagnetic field emitted from the outside.

[0002]

2. Description of the Related Art Non-powered transponders currently in practical use are supplied with power using an induction electromagnetic field or a radiated electromagnetic field as an energy transmission medium, and can be used even in a bad environment where oil or dust adheres. Therefore, it is used when maintenance-free is required. In addition, since it is a non-contact type, in order to ensure reliability and extend its life, a structure that considers environmental resistance, such as a glass tube encapsulation type or a resin molding type, is adopted. Further, since it is applied under the Radio Law, the transmission output of the response signal is regulated to be extremely small as compared with general wireless communication, so that it is often affected by noise. Therefore, it was necessary to investigate the noise environment in advance before applying the powerless transponder.

[0003]

Since the conventional non-power source transponder has a very small transmission output as described above, the influence of noise generated by the engine and motor of machinery and appliances, various electronic devices, general household electric appliances and the like. Easy to receive. If the specific frequency component of the noise is strong and it matches or is close to the transmission frequency of the unpowered transponder, it is necessary to change the setting to a frequency band that is not affected, but it is a sealed structure. It was an issue that could not be addressed. Even when changing to another transmission frequency, if the non-power transponder is embedded in or stuck to the structure,
There was a problem that it takes time to exchange.

The present invention has been made to solve the above problems, and the transmission frequency of the response signal can be changed by changing the frequency of the electromagnetic field radiated from the outside for power supply, and Aims to provide a powerless transponder that can be controlled by the identification information that stores the transmission timing of the response signal.

[0005]

A first powerless transponder of the present invention is an antenna 1 for transmitting and receiving electromagnetic waves to and from the outside in a powerless transponder of a simultaneous transmission / reception system used for contactless identification. 1. A rectification power supply circuit that uses the electromagnetic wave input received in 1 as a power supply, an oscillation circuit 4 that generates a frequency of a difference between the received electromagnetic wave and the transmitted electromagnetic wave by the output of the rectification power supply circuit, and the output of the oscillation circuit 4 A cross-modulation circuit that produces an output of an electromagnetic wave to be transmitted by cross-modulation with an electromagnetic wave, and the frequency of a response signal transmitted without a power source depends on the frequency of the electromagnetic wave being received. .

The second powerless transponder of the present invention is a simultaneous powerless transponder used for contactless identification, in which an antenna 1 for transmitting and receiving electromagnetic waves to and from the outside and an electromagnetic wave received by the antenna 1 are used. A rectifying power supply circuit using an input as a power supply; an oscillating circuit 4 having a non-modulating function and generating a frequency of a difference between an electromagnetic wave received by the output of the rectifying power supply circuit 4 and an electromagnetic wave to be transmitted;
A cross-modulation circuit that produces an electromagnetic wave output to be transmitted by cross-modulating the output of the oscillation circuit 4 and a received electromagnetic wave, and a memory 6 that stores identification information for modulation in the oscillation circuit 4.
And a modulation control circuit that accesses the memory 6 and modulates the oscillation circuit 4, and the frequency of the response signal modulated by the identification signal transmitted without power supply is the frequency of the electromagnetic wave being received. It is characterized by relying on.

[0007]

[Operation] In the first non-power supply transponder of the present invention having the above-mentioned configuration, the electromagnetic wave input from the outside is received by the antenna 1 and is input to the rectification power supply circuit, which is rectified and used as a power supply for each part. At the same time, the received electromagnetic wave output from the rectification power supply circuit is input to the oscillation circuit 4 and a frequency corresponding to the difference between the reception frequency and the transmission frequency is generated. The oscillation output and the received electromagnetic wave input are input to the cross modulation circuit to generate a transmission frequency by cross modulation, and the electromagnetic wave of this frequency is transmitted to the antenna 1
Will be fired from.

In the second powerless transponder of the present invention having the above-mentioned structure, the electromagnetic wave input from the outside is rectified by the rectification power supply circuit and used as the power supply for each part. The identification information stored in the memory 6 is accessed by the modulation control circuit when the received electromagnetic wave is input and input to the oscillation circuit 4, and the frequency of the difference between the reception frequency and the transmission frequency is modulated by the transmitted identification signal. The modulated wave and the received electromagnetic wave are input to the cross modulation circuit to generate a transmission electromagnetic wave by cross modulation, and the transmission electromagnetic wave is emitted from the antenna 1.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of an application form of a powerless transponder of the present invention. In FIG. 1, 10 is a contactless identification device having an information processing function, and 20 is a conveyor belt conveyor 50.
At the same time as supplying power by irradiating electromagnetic waves within the limited range indicated by the electromagnetic wave radiation region 60, to the powerless transponder 30 attached to each of the packages 40 carried by
The transmitter / receiver has a function (multi-channel reception function) of receiving response signals transmitted by a plurality of unpowered transponders 30 at different timings or at different transmission frequencies.

FIG. 2 shows one of the powerless transponders of the present invention.
It is a circuit block diagram of an Example. In FIG. 2, 1 is an antenna for transmitting and receiving electromagnetic waves to and from the outside, 2 is a limiter for suppressing the power of the electromagnetic wave input received by the antenna 1, and 3 is a rectifier for the electromagnetic wave input received by the antenna 1. A rectification power supply including a rectification circuit that supplies DC power to the oscillation circuit 4 and the like, and that includes a cross modulation circuit that generates a transmission frequency by cross modulation between the oscillation output of the oscillation circuit 4 and the electromagnetic wave input received by the antenna 1. It is a cross modulation circuit. Reference numeral 4 is an oscillator circuit that determines the transmission frequency of a powerless transponder using the output of the rectifier circuit as a power source. In other words, it is a circuit that oscillates a frequency that is the difference between the frequency of the electromagnetic wave input received by the antenna 1 and the transmission frequency, or a frequency that is a fraction thereof.

Since a modulation function (for example, FM or PM) can be added to the oscillation circuit 4 as required, a highly secure identification code (for example, a structure of several tens of bytes) stored in the memory 6 by the modulation / demodulation control circuit 5. However, if the powerless transponder according to the present invention is implemented only for the purpose of detecting the presence, the circuit configuration can be considerably simplified. That is, since the amount of information is 1 bit, only the response signal of the non-modulated carrier is required, so that the modulation function of the oscillation circuit 4, the modulation / demodulation control circuit 5 and the memory 6 are unnecessary. The demodulation control function of the modulation / demodulation control circuit 5 is a function of demodulating a received electromagnetic wave and accessing the memory 6 to store identification information to be stored. In this case, the memory 6 is a non-volatile EEPROM (Electrical Era) in which identification information can be written and read.
sable Programmable Read Only Memory) is used.

Next, the operation of the circuit of the powerless transponder of the present invention will be described. In the simultaneous transmission / reception system communication mode, the transmission / reception frequency interval must be sufficiently separated, and the transmission / reception device 20 connected to the contactless identification device 10
It is necessary to satisfy the separation degree of the demultiplexer, the selectivity characteristic of the receiver, and the sensitivity suppression characteristic. In this respect, the oscillation frequency band of the oscillation circuit 4 may be said to be determined by the frequency of the energy transmission medium used, and the type of the antenna 1 is also determined by the frequency band of the energy transmission medium. If a radiated electromagnetic field is used,
The frequency band is from several hundred MHz to several GHz, and the antenna 1 is an array antenna, and if an induction electromagnetic field is used, the frequency band is from several hundred KHz to several MH.
At z, the type of antenna 1 is an air core coil or a loop antenna.

The limiter 2 is not essential,
It is necessary to protect the rectification power supply / cross-modulation circuit 3 from an excessive input, but it can be omitted if a rectifying element having a sufficient excessive input withstand capability is used. A crystal oscillator is used in the oscillator circuit 4 because frequency stability is required, but when the output frequency is high (20 MHz or higher), the overtone type is used.
If it is low, a frequency divider circuit can be used together. The modulation / demodulation control circuit 5 is composed of a modulation control circuit and a demodulation control circuit, both of which operate after the output of the rectification power supply circuit of the rectification power supply / intermodulation circuit 3 has risen sufficiently.

The demodulation control circuit has a function of demodulating an electromagnetic wave received by the antenna 1 and accessing the memory 6 to store identification information. The modulation control circuit outputs the identification number of the identification information stored in the memory 6 to the oscillation circuit 4 as a modulation signal, and controls the start and stop of oscillation based on the transmission timing information. This is because oscillation is started after the output voltage of the rectification power supply circuit stabilizes and a stable frequency is obtained, and the oscillation frequency of the oscillation circuit 4 of each individual powerless transponder in the same electromagnetic wave irradiation region 60 is the same (transmission frequency This is to enable the response signal to be received at different timing settings even when the same).

The transmission / reception device 20 connected to the contactless identification device 10 has a plurality of powerless transponders 30 attached to a plurality of packages 40 on a conveyor belt conveyor 50.
On the other hand, it has a transmission function of radiating electromagnetic waves to supply power and operating an internal oscillation circuit to generate a transmission frequency by intermodulation with its own frequency. Also, the transmitter / receiver 2
The multi-channel reception function of 0 is a response signal transmitted from the plurality of unpowered transponders 30 with different transmission frequencies, or even if the transmission frequencies are the same, different transmission signals based on the transmission timing information stored in the memory 6. It is possible to receive all response signals transmitted at the timing of. The contactless identification device 10 includes a transmission / reception device 20.
It controls the transmission / reception function of the so that it is automatically operated, and performs the identification processing of the received information.

An electromagnetic wave input from the transmitter / receiver 20 is received by the antenna 1 and input to the rectification power supply circuit, rectified and used as a power supply for each section. Further, the reception electromagnetic wave output from the rectification power supply circuit is demodulated by the demodulation control circuit, and the identification information is stored in the memory 6. When the received electromagnetic wave is input, the identification number of the identification information stored in the memory 6 is output as a modulated signal by the modulation control circuit, and the modulated signal is input to the oscillation circuit 4. The received frequency (received electromagnetic wave) and the transmitted frequency (transmitted electromagnetic wave).
The frequency of the difference is modulated with the identification number transmitted according to the transmission timing. The modulated wave and the received electromagnetic wave are input to the cross modulation circuit to generate a transmission electromagnetic wave by cross modulation, and the transmission electromagnetic wave is emitted from the antenna 1.

[0017]

As described above, according to the present invention, the transmission frequency of the response signal of the powerless transponder can be changed by the frequency of the electromagnetic field radiated from the outside for power supply.
It is extremely easy to change the transmission frequency in the field when affected by noise, and since multiple transmission frequencies can be assigned and response signals can be sent at different timings, multiple unpowered transponders can be simultaneously transmitted in the same area. It can be identified, and the identification speed can be improved.
The practical effect is extremely large.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an application form of a powerless transponder of the present invention.

FIG. 2 is a circuit configuration diagram of an embodiment of a powerless transponder of the present invention.

[Explanation of symbols]

 1 Antenna 2 Limiter 3 Rectification Power Supply / Intermodulation Circuit 4 Oscillation Circuit 5 Modulation / Demodulation Control Circuit 6 Memory 10 Contactless Identification Device 20 Transmitter / Receiver 30 Non-Power Transponder 40 Baggage 50 Conveyor Belt Conveyor 60 Electromagnetic Radiation Area

Claims (12)

[Claims] 1. A simultaneous transmission / reception type powerless transponder used for contactless identification, an antenna for transmitting and receiving electromagnetic waves to and from the outside, a rectification power supply circuit using an electromagnetic wave input received by the antenna as a power supply, An oscillating circuit for generating a frequency of a difference between an electromagnetic wave received and an electromagnetic wave to be transmitted by the output of the rectification power supply circuit, and a cross modulation circuit for generating an electromagnetic wave output to be transmitted by cross modulation of the output of the oscillating circuit and the received electromagnetic wave. However, the frequency of the response signal transmitted without a power source depends on the frequency of the electromagnetic wave being received, and the powerless transponder. 2. A powerless transponder according to claim 1, wherein all electric circuit components are hermetically sealed in a glass tube. 3. The powerless transponder according to claim 1, wherein all electric circuit parts are hermetically sealed in a case made of synthetic resin. 4. A simultaneous transmission / reception type powerless transponder used for contactless identification, an antenna for transmitting and receiving an electromagnetic wave to and from the outside, a rectifying power supply circuit using an electromagnetic wave input received by the antenna as a power source, An oscillating circuit having a modulation function, which generates a frequency of a difference between an electromagnetic wave received by the output of the rectifying power supply circuit and an electromagnetic wave to be transmitted, and an electromagnetic wave output transmitted by intermodulation of the output of the oscillating circuit and the received electromagnetic wave. An intermodulation circuit that occurs, a memory that stores identification information for modulation in the oscillation circuit, and a modulation control circuit that accesses the memory to perform modulation in the oscillation circuit A powerless transponder characterized in that the frequency of the response signal modulated with the signal depends on the frequency of the electromagnetic wave being received. 5. The powerless transponder according to claim 4, wherein all electric circuit components are hermetically sealed in a glass tube. 6. The powerless transponder according to claim 4, wherein all electric circuit components are hermetically sealed in a case made of synthetic resin. 7. Demodulating identification information from the received electromagnetic wave,
5. The powerless transponder according to claim 4, further comprising a demodulation control circuit for accessing the memory and storing it. 8. A powerless transponder according to claim 7, wherein all electric circuit components are hermetically sealed in a glass tube. 9. The powerless transponder according to claim 7, wherein all electric circuit components are hermetically sealed in a case made of synthetic resin. 10. The identification information is composed of an identification number and transmission timing information, and the modulation control circuit starts the oscillation circuit at the set transmission timing, modulates with the identification number, and then stops. The non-power transponder according to claim 4, wherein the transponder has no power supply. 11. The powerless transponder according to claim 10, wherein all electric circuit components are hermetically sealed in a glass tube. 12. The electric circuit component is hermetically sealed in a case made of synthetic resin.
Non-powered transponder as described.