JPH0675269B2 - IC card identification method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type identification method for identifying and determining a code recorded on an IC card by using radio waves.

[0002]

2. Description of the Related Art In a method of reading a code recorded on an IC card with an electromagnetic wave, the I-wave is read according to the rate at which the electromagnetic wave emitted from a reader is received by the IC card.
The reading sensitivity of the C card is determined, and when this ratio is small, the receiving sensitivity is also lowered, that is, the identification sensitivity is lowered, it is difficult to read the code of the IC card accurately, and the reader malfunctions often. , Can not be read accurately. Therefore, in order to read the code of the IC card, it was necessary to bring the IC card near the antenna of the reader. For example, as one example, when applied to the management of a car that goes in and out of a parking lot of an unmanned car, the car is always stopped at a predetermined position, or the driver gets off the car and a predetermined IC card is set. It is necessary to bring the IC card to the position of the IC card so that the reader can read the code of the IC card. It was often difficult.

[0003]

DISCLOSURE OF THE INVENTION The present invention greatly relaxes the regulations on the position and distance at which the code of an IC card can be read in relation to the antenna of the reader and the IC card. Then, the code reading of the IC card is efficiently performed so that the IC card can be properly managed.

[0004]

In order to solve the above-mentioned problems, the present invention comprises a resonance circuit formed by a reader antenna and a loop antenna, and an IC card. The operation uses a loop-shaped antenna that receives the electromagnetic wave energy radiated from the antenna of the reader several to several tens of times as high as the high frequency energy received by an ordinary IC card. The received high frequency energy is re-radiated to the high frequency electromagnetic field by the resonance circuit, and the electromagnetic field around the loop antenna is increased to increase the IC card.
The energy received by the scanner is increased to improve the identification sensitivity of the reader. In order to receive more electromagnetic waves from the reader, it is necessary to increase the receiving area, and in order to expand the receiving area, the loop area is several times to several tens times the area of the IC card. Use a circular antenna to increase the received energy. A method of increasing the electromagnetic field around the loop antenna is to use a series resonance circuit in which the power received by the loop antenna is connected to the inductance of the loop antenna in series with a capacitance. Supply, increase the current in the resonance circuit and re-radiate electromagnetic waves,
It strengthens the electromagnetic field. Therefore, a strong electromagnetic field is applied to the IC card placed near the loop-shaped antenna,
Power received by the IC card by the code of the IC card
By turning on and off, the receiving power is not consumed and the equivalent series resistance of the resonance circuit is increased or decreased to change the current of the resonance circuit and change the electromagnetic field. . That is, by changing the consumption of high frequency power in the IC card, the electromagnetic field around the IC card is changed to affect the electromagnetic field around the antenna of the reader, in other words, the antenna Even if the IC card is not brought close to the antenna of the reader by changing the mutual impedance, the ID card is brought close to the loop-shaped antenna forming the resonance circuit. The code of the code can be read accurately.

[0005]

The loop-shaped antenna forming a resonant circuit tuned to the frequency of the electromagnetic wave emitted from the reader locally enhances the electromagnetic field, and the enhanced electromagnetic field is integrated into the IC.
By installing the card, the high frequency energy received by the IC card increases. If the received high frequency energy is short-circuited with a low resistance, the high frequency power will be consumed in the IC card, the equivalent series resistance of the resonance circuit will increase, and the current in the resonance circuit will decrease. The world becomes weak. As a result, more radio frequency energy will be delivered from the reader's antenna. That is, since the impedance of the antenna of the reader becomes low and the power supplied from the reader to the antenna increases, it is possible to read the code of the IC card by measuring the supplied power. It is possible.

A high-frequency wave is radiated from the antenna of the reader and received by the loop antenna, and a series resonance circuit is formed by connecting the loop antenna inductance and capacitance in series. Therefore, if the resonance frequency of this resonant circuit is tuned to the frequency radiated from the antenna of the reader, when the electromagnetic wave from the reader is received by the loop antenna, the resonant circuit of the loop antenna is Becomes resonant. At this time, the current of the series resonance circuit is a current determined only by the series resistance component. If the series resistance component is reduced, the current in the resonance circuit will increase, and the electromagnetic field near the loop-shaped antenna will become a very strong electromagnetic field compared to when this antenna is not present, and this strong electric field will IC card placed in a magnetic field
The high frequency energy received by the receiver increases. When this high frequency energy is consumed by the IC card, the loss of the resonance circuit formed by the loop-shaped antenna increases, the current of the resonance circuit decreases, and the strength of the surrounding electromagnetic field decreases. However, more high frequency power is supplied from the antenna of the reader. I by the code of IC card
Since changing the consumption of the power supplied to the C card causes a change in the power supply from the antenna of the reader, the change in the power supply from the reader should be read by the reader. The code of the IC card can be read by the reader. The read code is discriminated and judged, and the control device is operated to perform necessary management. It should be noted that the antenna and the loop antenna of the reader described here, and the IC
Although the interaction with the card is explained as a single circuit, these three circuits are circuits connected by the interaction, and their exact actions are obtained as the solution of simultaneous equations. However, the function is simplified and explained by a single circuit.

[0007]

EXAMPLE One example of the present invention will be described when it is applied to management of an automobile parking lot. FIG. 1 is a block diagram for explaining the function when one embodiment of the present invention is applied to car parking management. Reference numeral 1 is an antenna of a reader 5 and code of an IC card 4. Is also a non-contact type detector that radiates a high frequency for reading a code signal of the IC card 4, and 2 is a vehicle to be managed, and 2 is a route to the vehicle 2 to be managed. If the resonance circuit 3 constituted by the antenna is installed in the windshield or the glass portion of the door, and 4 is an IC card, and the vehicle driver comes near the antenna 1 of the reader 5, slow down, Alternatively, stop and turn the IC card 4 to the loop antenna 3
When approaching the vicinity of, the radiation impedance of the antenna 1 changes due to the interaction between the code of the IC card 4 and the loop-shaped antenna resonance circuit 3 and the antenna 1. The change is read by the reader 5, and the read code code is read.
The vehicle is sent to the gate opening / closing control device 6, and the gate opening / closing control device 6 operates the gate 7 to open / close the gate to manage the entrance / exit of the automobile.

FIG. 2 is a block diagram for explaining an electric function for explaining the electric function of the present invention. IC card 4
Reference numeral 8 designates a synthetic resin hermetically sealed chip, which is a circuit for supplying an operating power source by a high frequency signal to read an internal code signal, that is, a circuit which is difficult to discontinue and forge, and 8 is an antenna for receiving a high frequency, A part of the signal received at 8 is rectified by a diode 9a to be a direct current, smoothed by an electrostatic capacitance 9b, and a constant voltage diode 9c is used to make an encoder 1 of an IC card.
The IC card is configured to prevent overvoltage from being applied to 0.
Power supply for the power supply. When the encoder 10 is powered by the power source 9, the encoder 10 operates, but when the induced voltage by the antenna 8 is low, the voltage of the power source 9 becomes low and the operation of the encoder 10 is unstable, so that the encoder 10 has a sufficient function. Can no longer fulfill. The encoder 10 has a code for managing individuals.
The code is recorded and is the most important for management. When the encoder 10 is supplied with power from the power source 9, it operates according to the program recorded in the encoder 10, and the recorded code is recorded.
The contactless switch 11 is operated in accordance with the command, the receiving antenna 8 is short-circuited by the resistor 11a, and the high frequency signal received by the antenna 8 is consumed by the resistor 11a. When the non-contact switch 11 is off, only the encoder 10 of the IC card operates, which is much smaller than the power consumed by the resistor 11a. When turned on and off according to the code of the mode, the high frequency power supplied from the antenna 8 is consumed or not consumed by the resistor 11a, and as a result, the high frequency power in the IC card is consumed. The code of the IC card is converted into the change of the supply power of the reader 5 as a result.

Reference numeral 3 is a resonance circuit, 3a is an inductance of a loop antenna, and 3b is an inductance 3
3a is a capacitance for series resonance connected in series with a, 3c is a capacitance for fine adjustment used as necessary, 3d is an equivalent series resistance, and a capacitance connected in parallel with the inductance 3a. The resonance frequency of the series resonance circuit 3 with 3b and 3c is matched with the frequency radiated from the reader 5 described later. In the series resonance circuit 3, the current flowing when the series resonance circuit 3 resonates is equivalent to the series resistance circuit 3 d of the series resonance circuit 3.
If the resistance 3d is very small, the flowing current can be very large even if the electromotive voltage supplied is small. The power consumption is due only to the resistance 3d, and the power supplied from the antenna 1 of the reader 5 is also greatly affected by the equivalent series resistance 3d of the resonance circuit 3. The consumption of the high frequency power received in the IC card 4 installed near the resonance circuit 3 increases the equivalent series resistance 3d of the resonance circuit 3. Therefore,
A resonant circuit is supplied to the loop-shaped antenna 3 by supplying a voltage induced in the loop-shaped antenna 3 to the series circuit of the inductance 3a of the loop-shaped antenna 3 and the electrostatic capacitances 3b and 3c connected in parallel. The electromagnetic field generated by this is received by the IC card,
By consuming the receiving power in the IC card, a change is given to the electromagnetic field, and this change is detected by the antenna 1 of the reader 5. Since the induced electromotive force is almost proportional to the cross-sectional area of the loop-shaped antenna 1, it can be made much larger than the cross-sectional area of the IC card, so that the induced voltage can be easily increased and the effect is further improved. It is a big one.

In FIG. 2, reference numeral 1 denotes an antenna of the reader 5, which emits an electromagnetic wave to read the code of the IC card and changes the response of the IC card to the mutual impedance change of the antenna. 5a is an oscillator for supplying a high frequency to the antenna, and 5b is an IC card cord.
Is a response signal detector for detecting a change in the output of the power supplied from the oscillator 5a due to a change in the impedance of the antenna 1 caused by a change in the consumption of the received signal of the IC card. It is a code signal detector that produces a response signal from the relationship with the device 5b. The output of the code signal detector 5c is sent to the gate opening / closing control device 6,
The gate of the IC card is controlled by the gate opening / closing controller 6.
It is judged whether the code is to be released or not, and the judgment result is sent to the gate opening / closing machine to manage the opening / closing of the gate.

Although the management of the car parking lot has been described as an embodiment of the present invention, the present invention can be used not only for car management but also for identification of individual human beings. For example, the resonance circuit 3 of a loop antenna is used. It is used as a necklace, especially without bringing the IC card close to the reader.
In addition, it is not necessary to use the electrostatic capacity 3c for fine adjustment when it is not necessary, and the point is that the electromagnetic relationship between the antenna 1 of the reader 5 and the IC card 4 is looped. An IC based on a mutual impedance change of the antenna, characterized in that the code of the IC card can be read by the antenna 1 even if the antenna 1 is connected through the resonance circuit 3 of the antenna. This is a card identification method.

[0012]

According to the present invention, IC card management can be performed with extremely high sensitivity and efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram when an embodiment of the present invention is applied to management of an automobile parking lot.

FIG. 2 is an electric functional block diagram showing an electric function of the present invention.

[Explanation of symbols]

1 ... Antenna of reader, 2 ... Car to be managed, 3 ...
Loop-shaped antenna resonance circuit, 3a ... loop-shaped antenna inductance, 3b, 3c ... resonance circuit electrostatic capacitance,
3d ... Equivalent series resistance, 4 ... IC card, 5 ... IC card code reader, 5a ... Oscillator, 5b ... Response signal detector, 5c ... Code signal detector, 6 ... Gate opening / closing control device, 7 ... Gate, 8 ... Antenna of IC card, 9 ... Power supply of IC card, 9a ... Rectifying diode, 9b ... Electric capacity,
9c ... Constant voltage diode, 10 ... Encoder, 11 ... Non-contact switch, 11a ... Resistor.

Claims (2)

[Claims] 1. I due to mutual impedance change of antennas
In the C-card identification method, an electromagnetic field of an electromagnetic wave radiated from an antenna of an identification / determination unit is placed in the vicinity of an IC card to be identified and is composed of a loop-shaped antenna with a small loss and a capacitance. By the resonant circuit
An IC card identification method in which the electromagnetic waves supplied to the C card are increased to efficiently identify the code of the IC card. 2. A gate for opening and closing a car for entering and exiting a parking lot by identifying and judging the code in the IC card by bringing an IC card having no battery close to the resonance circuit. The method for identifying an IC card according to claim 1, which is operated.