JPH11232418A - Non-contact ic card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize communication in a wide range by defecting the intensity of a radio wave by means of a level detection circuit part and controlling a detection circuit by adjusting it in conformity with the intensity. SOLUTION: A radio wave from an outer device is received by an antenna part 7 and the bridge circuit of a rectification circuit part 2 generates the driving power of a non-contact IC card, changes the amplitude of a sine wave in proportion to the intensity of the radio wave and changes the level of power. Thus, a level detection circuit part 3 detects the intensity of the radio wave from the level of power. A detection circuit part 1 adjusts a time constant by adjusting it in conformity with the intensity of the radio wave by information from the circuit part 3 and detects a clock signal by half-wave rectification from a sine waveform. A modulation/demodulation circuit 4 converts the detected clock signal into data of a command and the like. Converted data is transmitted to a control circuit part 5 and the command is judged and the data is transmitted to a memory part 6 and the command is executed. Even if the intensity of the radio wave changes, communication in a wide rang can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact IC card which supplies and communicates power using radio waves to write and read data in a non-contact manner. It relates to the function of simultaneous communication with a plurality of individuals.

[0002]

2. Description of the Related Art In recent years, non-contact ICs have been used for identifying moving objects.
A card is being used, and necessary data is written in a memory, and data is read / written by an external device. Since this non-contact IC card has no terminals, it is difficult to forge and has higher reliability than a contact type IC card.

As shown in FIG. 5, a conventional non-contact IC card includes an antenna 7, a rectifier 2 connected to the antenna 7, a detector 16 connected to the antenna 7, and a detector 16 connected to the antenna 7. , A control circuit section 5 connected to the modulation / demodulation circuit section 4, and a memory section 6 connected to the control circuit section 5.

A radio wave transmitted from an external device is received by an antenna unit 7. The sine wave received by the antenna unit 7 generates power for driving the non-contact IC card by the bridge circuit of the rectification circuit unit 2. The detection circuit 16 detects a clock signal from the sine waveform received by the antenna unit 7 by half-wave rectification. Modulation / demodulation circuit 4
Is obtained from the clock signal detected by the detection circuit unit 16.
Converts data such as commands and addresses. The converted data is transmitted to the control circuit unit 5 to determine a command such as write / read, and to transmit an address, write data, and the like to the memory unit 6 and execute the command.

[0005]

In the conventional non-contact IC card, the communication distance can be extended by strengthening the radio wave of the external device. However, since the radio wave is strong at a short distance, the time constant of the detection circuit is adjusted. As a result, the clock signal cannot be detected normally, and an inoperable area is created at a short distance.

In addition, since there is no security function, data can be read freely, and unauthorized data change and forgery are easy. Furthermore, when a plurality of non-contact IC cards exist in the communicable area, it is necessary to select one to perform communication and stop communication with the other, and simultaneous access was not possible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-contact IC card capable of performing communication over a wide range, having a security and anti-counterfeit function, and capable of simultaneously communicating with a plurality of IC cards without malfunction. I do.

[0008]

The non-contact IC card of the present invention is configured to detect the intensity of a radio wave and to control a detection circuit in accordance with the intensity of the radio wave. Communication can be enabled.

Further, the non-contact IC card of the present invention has a plurality of antennas and a plurality of detection circuit units externally, communicates at a plurality of frequencies, and transmits commands and passwords at a plurality of frequencies. It has an excellent security function and can prevent forgery.

Further, a non-contact IC card according to the present invention has a plurality of antennas, a plurality of detection circuit units, and a plurality of modulation / demodulation circuits, and is configured to perform communication at a plurality of frequencies. When a plurality of non-contact IC cards are present in the available area, communication using a frequency that is not used enables simultaneous communication with the plurality of non-contact IC cards without malfunction.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides an antenna unit for receiving a radio wave, a rectifier circuit unit for generating power from the received radio wave, and a radio wave intensity based on the generated power supply voltage. A level detection circuit section for detecting, a detection circuit section for changing a time constant by a signal from the level detection circuit section and detecting a clock signal in accordance with the intensity of radio waves, and modulating / modulating a clock signal detected by the detection circuit section. It has a modulation / demodulation circuit for demodulating, a control circuit for controlling each operation, and a non-volatile memory for storing data. The level detection circuit detects the strength of radio waves due to the communication distance, and the detection circuit. To detect the clock signal normally and
By transmitting the signal to the demodulation circuit, communication over a wide range is enabled.

According to a second aspect of the present invention, an antenna unit for receiving a plurality of radio waves, a rectifying circuit unit for generating power from the received radio waves, and detecting the strength of the radio waves from the generated power supply voltage. A level detection circuit section, a detection circuit section having a plurality of detection circuits having different time constants and selecting a detection circuit based on a signal from the level detection circuit section, and a modulation section for modulating / demodulating a clock signal detected by the detection circuit section. / Demodulation circuit section, which has a control circuit section for controlling each operation and a non-volatile memory section for storing data, and selects and detects a detection circuit having an optimal time constant with respect to the strength of radio waves depending on the communication distance. The communication to a wide range was enabled by telling to.

According to a third aspect of the present invention, there is provided an antenna unit for receiving a plurality of radio waves, a rectifying circuit unit for generating power from the received radio waves, and a plurality of detection circuits connected to each of the antennas. A detection circuit unit, a modulation / demodulation circuit unit having a plurality of modulation / demodulation circuits for modulating / demodulating the clock signal detected by the detection circuit unit, and determining a command or a password based on a signal from the modulation / demodulation circuit unit. It has a judgment circuit unit, a control circuit unit that controls each operation, and a non-volatile memory unit that stores data. By communicating commands and passwords using radio waves of multiple frequencies, security is enhanced and counterfeiting is performed. Can be prevented.

According to a fourth aspect of the present invention, there is provided an antenna unit for receiving a plurality of radio waves, a rectifying circuit unit for generating power from the received radio waves, and a plurality of detection circuits connected to each of the antennas. A detection circuit unit; and a plurality of modulation / demodulation units for modulating / demodulating the clock signal detected by the detection circuit unit.
A demodulation circuit, a selection circuit for selecting a clock signal modulated / demodulated by the modulation / demodulation circuit, a control circuit for controlling each operation, and a non-volatile memory for storing data; When a plurality of non-contact IC cards exist in the communicable range, communication is performed without malfunction by performing communication using radio waves of different frequencies.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) First, in Embodiment 1 of the present invention, a description will be given of the realization of a wide range of communication distance of a non-contact IC card. FIG. 1 is a circuit diagram according to the first embodiment of the present invention. An antenna unit 7, a rectification circuit unit 2 connected to the antenna unit 7, a level detection circuit unit 3 connected to the rectification circuit 2, and an antenna unit 7 A detection circuit unit 1 connected to the level detection circuit unit 3, a modulation / demodulation circuit unit 4 connected to the detection circuit unit 1, a control circuit unit 5 connected to the modulation / demodulation circuit unit 4, and a connection to the control circuit unit 5. And a memory unit 6.

Radio waves transmitted from an external device are received by the antenna unit 7. The sine wave received by the antenna unit 7 generates power for driving the contactless IC card by the bridge circuit of the rectifier circuit unit 2. The amplitude of the sine wave received by the antenna unit 7 changes in proportion to the strength of the radio wave, and the level of the power generated by the rectifier circuit 2 changes. From this, the level detection circuit unit 3 includes the rectifier circuit 2
The strength of the radio wave is detected from the level of the power generated. Detection circuit unit 1 based on information from level detection circuit unit 3
Adjusts the time constant according to the strength of the radio wave, and detects a clock signal by half-wave rectification from the sine waveform received by the antenna unit 7. The modulation / demodulation circuit 4 converts a clock signal detected by the detection circuit unit 1 into data such as a command and an address. The converted data is transmitted to the control circuit unit 5 to determine a command such as reading and writing, and to transmit an address and write data to the memory unit 6 and execute the command. From the above, communication over a wide range can be made possible by having a detection circuit that can receive even if the intensity of radio waves changes.

(Embodiment 2) Next, in Embodiment 2 of the present invention, a description will be given below of the realization of a wide communication distance of a non-contact IC card. FIG. 2 is a circuit diagram of the second embodiment of the present invention. The antenna unit 7, the rectification circuit unit 2 connected to the antenna unit 7, the level detection circuit unit 3 connected to the rectification circuit 2, and the antenna unit 7 A detection circuit unit 8 connected to the level detection circuit unit 3 and a conversion circuit connected to the detection circuit unit 8
It comprises a demodulation circuit section 4, a control circuit section 5 connected to the modulation / demodulation circuit section 4, and a memory section 6 connected to the control circuit section 5.

Radio waves transmitted from an external device are received by the antenna unit 7. The sine wave received by the antenna unit 7 generates power for driving the contactless IC card by the bridge circuit of the rectifier circuit unit 2. The amplitude of the sine wave received by the antenna unit 7 changes in proportion to the strength of the radio wave, and the level of the power generated by the rectifier circuit 2 changes. From this, the level detection circuit unit 3 includes the rectifier circuit 2
The strength of the radio wave is detected from the level of the power generated. The detection circuit section 8 has a plurality of detection circuits (detection circuits A, B, C...) Having different time constants, and based on information from the level detection circuit section 3, the detection circuit section 8 An appropriate detection circuit is selected according to the strength of the radio wave, and a clock signal is detected from the sine waveform received by the antenna unit 7 by half-wave rectification. The modulation / demodulation circuit 4 converts a clock signal detected by the detection circuit unit 8 into data such as a command and an address. The converted data is transmitted to the control circuit unit 5 to determine a command such as read or write, and to transmit an address or write data to the memory unit 6 and execute the command. From the above, communication over a wide area can be made possible by having the detection circuit unit that can receive even if the intensity of the radio wave changes.

(Embodiment 3) Next, in Embodiment 3 of the present invention, a security function of a non-contact IC card will be described below. FIG. 3 is a circuit diagram according to a third embodiment of the present invention.
Antenna unit 13, antenna unit 14. . . And the rectifier circuit unit 2 connected to the antenna unit 7, the antenna unit 12, the antenna unit 13, the antenna unit 14. . . A detection circuit unit 9 connected to the detection circuit unit; a modulation / demodulation circuit unit 10 connected to the detection circuit unit 9;
It comprises a determination circuit section 11 connected to the modulation / demodulation circuit section 10, a control circuit section 5 connected to the determination circuit section 11, and a memory section 6 connected to the control circuit section 5.

Radio waves of a plurality of frequencies are transmitted from the external device, and communication is performed by the plurality of radio waves. The sine wave received by the antenna unit 7 generates power for driving the present IC card by the bridge circuit of the rectifier circuit unit 2. The detection circuit section 9 includes an antenna section 12, an antenna section 13, an antenna section 14,... Corresponding to each frequency so that a plurality of frequencies can be received. . . And a detection circuit (detection circuit A, detection circuit B, detection circuit C...) Respectively connected thereto, and simultaneously receives signals of a plurality of frequencies. Antenna unit 12, antenna unit 13, antenna unit 14. . . The sine wave received by each of the detection circuits A, B, C. . . To detect the clock signal after half-wave rectification. The modulation / demodulation circuit unit 10 includes a detection circuit A,
Detection circuit B, detection circuit C. . . And a modulation / demodulation circuit A, a modulation / demodulation circuit B, and a modulation / demodulation circuit C. . .
And converts the clock signal detected by the detection circuit unit 9 into data such as a command and an address.

In the determination circuit, each data converted by the modulation / demodulation circuit unit 10 is determined, and after confirming its validity,
Data such as commands and addresses are transmitted to the control circuit unit 5. As a method of confirming the validity, a command can be divided into each radio wave and transmitted and combined, or a password can be transmitted by each radio wave and collated. Control circuit unit 5
Determines a command such as reading or writing from data, transmits an address or write data to the memory unit 6, and causes the memory unit 6 to execute the command. From the above, it is possible to provide a security function.

(Embodiment 4) Next, in Embodiment 4 of the present invention, simultaneous communication with a plurality of contactless IC cards will be described below. FIG. 4 is a circuit diagram of a fourth embodiment of the present invention, in which a plurality of antenna units 7, antenna units 12,
Antenna unit 13, antenna unit 14. . . And the rectifier circuit unit 2 connected to the antenna unit 7, the antenna unit 12, the antenna unit 13, the antenna unit 14. . . A detection circuit unit 9 connected to the detection circuit unit; a modulation / demodulation circuit unit 10 connected to the detection circuit unit 9;
It comprises a selection circuit section 15 connected to the modulation / demodulation circuit section 10, a control circuit section 5 connected to the selection circuit section 15, and a memory section 6 connected to the control circuit section 5.

Radio waves transmitted from the external device are transmitted to the antenna unit 7, the antenna unit 12, the antenna unit 13, the antenna unit 14. . . Is received by The sine wave received by the antenna unit 7 generates power for driving the present IC card by the bridge circuit of the rectifier circuit unit 2. The detection circuit unit 9 includes an antenna unit 12, an antenna unit 13, and an antenna unit 1 corresponding to each frequency so that a plurality of frequencies can be received.
4. . . Detection circuits (detection circuits A,
Detection circuit B, detection circuit C. . . ) To simultaneously receive signals of a plurality of frequencies. Antenna unit 12, antenna unit 13, antenna unit 14. . . The sine wave received by each of the detection circuits A, B, C. . . To detect the clock signal after half-wave rectification. The modulation / demodulation circuit 10 includes a detection circuit A, a detection circuit B, and a detection circuit C. . . And a modulation / demodulation circuit A, a modulation / demodulation circuit B, and a modulation / demodulation circuit C. . . And converts the clock signal detected by the detection circuit unit 9 into data such as a command and an address.

In the selection circuit section 15, the modulation / demodulation circuit section 10
A communicable frequency is selected from each data converted by the above. The selection method is determined using a password (such as the serial number of each IC card). The selection circuit section 15 transmits data such as a command and an address of the selected frequency to the control circuit section 5. The control circuit unit 5 determines a command such as reading or writing from the data, transmits an address or write data to the memory unit 6, and causes the memory unit 6 to execute the command. From the above, multiple ICs
Communication becomes possible simultaneously with the card.

As described above, in the fourth embodiment, the external device and the IC card can communicate at a plurality of frequencies. When one IC card is communicating at the frequency A in the communication range and another IC card is within the communication range, the communication is performed at the frequency B so that a plurality of IC cards can be simultaneously communicated. It is possible to communicate with.

[0026]

As described above, the non-contact IC card of the present invention detects the intensity of the radio wave and controls the detection circuit in accordance with the intensity of the radio wave. Communication can be enabled.

Further, it has a plurality of antennas, a plurality of detection circuits, and a plurality of modulation / demodulation circuits, communicates at a plurality of frequencies, and transmits commands and passwords at a plurality of frequencies. As a result, an excellent security function can be obtained and forgery can be prevented.

Further, when communication can be performed at a plurality of frequencies and a plurality of non-contact IC cards are present in the communicable area, communication is performed using an unused frequency, so that a plurality of non-contact IC cards can be simultaneously operated without malfunction. It is possible to communicate with.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a contactless IC card according to a first embodiment of the present invention which enables a wide range of communication.

FIG. 2 is a circuit diagram of a non-contact IC card according to a second embodiment of the present invention which enables a wide range of communication.

FIG. 3 is a circuit diagram of a non-contact IC card according to a third embodiment of the present invention, which has excellent security and can prevent forgery;

FIG. 4 is a circuit diagram of a non-contact IC card according to a fourth embodiment capable of communicating with a plurality of IC cards without malfunction of the present invention.

FIG. 5 is a circuit diagram of a conventional non-contact IC card.

[Explanation of symbols]

1 A detection circuit section capable of changing a time constant 2 A rectification circuit section for rectifying radio waves to generate power 3 A level detection circuit section for detecting a power supply level 4 A modulation / demodulation circuit section for demodulating and modulating a detected signal 5 Instructions Control circuit unit for performing determination and operation control 6 Non-volatile memory circuit unit for storing data 7 Antenna unit 8 Detection circuit unit that can select a detection circuit according to the strength of radio waves 9 Has a plurality of detection circuits that can handle a plurality of frequencies Detection circuit section 10 Modulation / demodulation circuit for modulating / demodulating signals of a plurality of frequencies 11 Judgment circuit section for judging command and password 12 Antenna section 13 Antenna section 14 Antenna section 15 Selection circuit section for selecting a detection circuit according to communication frequency

Claims (4)

[Claims] 1. An antenna unit for receiving a radio wave, a rectifier circuit unit for generating power from the received radio wave, a level detection circuit unit for detecting the strength of the radio wave from the generated power supply voltage, and A detection circuit for detecting a clock signal in accordance with the intensity of the radio wave by changing the time constant in accordance with the signal; a modulation / demodulation circuit for modulating / demodulating the clock signal detected by the detection circuit; and controlling each operation. It has a control circuit section and a non-volatile memory section for storing data. The level detection circuit section detects the strength of radio waves due to the communication distance, and controls the detection circuit section to normally detect and change the clock signal. A non-contact IC card, which is transmitted to a demodulation circuit unit. 2. An antenna unit for receiving a plurality of radio waves, a rectifying circuit unit for generating power from the received radio waves, a level detection circuit unit for detecting the intensity of the radio waves from the generated power supply voltage, and a time constant different from each other. A detection circuit section having a plurality of detection circuits and selecting a detection circuit based on a signal from the level detection circuit section; a modulation / demodulation circuit section for modulating / demodulating a clock signal detected by the detection circuit section; Non-contact IC, comprising: a control circuit unit for performing the operation and a non-volatile memory unit for storing data, wherein a detection circuit having an optimal time constant is selected and transmitted to a demodulation circuit unit with respect to the strength of radio waves depending on the communication distance. card. 3. An antenna unit for receiving a plurality of radio waves, a rectifier circuit unit for generating power from the received radio waves, a detection circuit unit having a plurality of detection circuits connected to each of the antennas, A modulating / demodulating circuit section having a plurality of modulating / demodulating circuits for modulating / demodulating the detected clock signal; a judging circuit section for judging an instruction or a password by a signal from the modulating / demodulating circuit section; and controlling each operation. A non-contact IC card comprising a control circuit section and a non-volatile memory section for storing data, wherein commands and passwords are communicated using radio waves of a plurality of frequencies. 4. An antenna unit for receiving a plurality of radio waves, a rectifier circuit unit for generating power from the received radio waves, a detection circuit unit having a plurality of detection circuits connected to each of the antennas, Modulates the detected clock signal /
A plurality of modulation / demodulation circuit sections for demodulation; a selection circuit section for selecting a clock signal modulated / demodulated by the modulation / demodulation circuit section; a control circuit section for controlling each operation; and a nonvolatile memory for storing data A non-contact IC card comprising: a plurality of non-contact IC cards, wherein when a plurality of non-contact IC cards exist in a communicable range, communication is performed using radio waves of different frequencies.