JP2002319002A - Noncontact information carrier reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To address the problem of a noncontact information carrier reader: that when a noncontact IC card reader/writer continuously or intermittently modulates a carrier radio wave and transmits a command to a noncontact IC card or a tag and then waits for response from the noncontact IC card or the tag, the noncontact IC card reader/writer or a host computer is limited as to the time it spends on other processes. SOLUTION: The noncontact IC card or the tag is supplied with electric power from the carrier radio wave of the noncontact IC card reader/writer. Normally, the carrier radio wave (unmodulated) is transmitted and the approach of a noncontact IC or tag is automatically detected from a change in the waveform of a carrier output, so that the noncontact IC card reader/writer or the host computer can be applied exclusively to other processes.

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
In a non-contact IC card or tag supplied from a carrier wave of a card reader / writer, a carrier radio wave (unmodulated) is normally transmitted, and the approach of the non-contact IC card or tag is automatically detected by a change in the carrier output waveform. It relates to the method of detection.

[0002]

2. Description of the Related Art A non-contact IC card reader / writer continuously or intermittently modulates a carrier wave and sends a command to a non-contact IC card or tag, and waits for a return from the non-contact IC card or tag.

[0003]

SUMMARY OF THE INVENTION Non-contact I
When a non-contact IC card reader / writer continuously or intermittently modulates a carrier wave and sends a command to a C card or tag, and waits for a response from the non-contact IC card or tag, the non-contact IC card reader / writer And higher-end computers had limited time spent on other tasks.

[0004] The present invention solves the above-mentioned problems, and automatically detects the approach of a non-contact IC or tag, during which time the non-contact IC card reader / writer or a host computer concentrates on other processing. The purpose is to be able to.

[0005]

According to the present invention, there is provided a contactless IC card or tag supplied with electric power from a carrier wave of a noncontact IC card reader / writer. ) To automatically detect the change in the carrier output waveform when the non-contact IC or tag approaches, so that the non-contact IC card reader / writer and the host computer can concentrate on other processing during that time. It is a means to make it possible.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Many non-contact ICCRs operate by rectifying electric power from a reader / writer to a carrier (non-modulated output) radio wave and converting it to its own power. In this case, it is important for the reader / writer that no modulation is necessary and that power transmission is possible. In FIG. 1, the signal supply unit 2
Can transmit a modulated wave by the central processing unit 5, but can output a non-modulated output when there is no control from the central processing unit 5. Through the filter circuit 7, the unmodulated output wave from the antenna 1 and the signal supply unit 2 is transmitted as a radio wave. The waveform input to the antenna 1 at this time is a sine wave, but if a non-contact IC card comes near the antenna 1, the waveform input to the antenna 1 will be distorted. This is because the non-contact IC card receives electric power, and the shape of the sine wave is distorted in the direction of decreasing the area. The magnitude of this distortion is transmitted via the transmission signal detection unit 3 and the comparison unit 4 compares the waveform from the signal supply unit 2 to determine whether the distortion is equal to or greater than a certain value. Can be detected. If there is a certain level of distortion, the comparing unit 4 inverts the output signal and uses it as a distortion detection signal. By the distortion signal, the central processing unit 5 can shift the processing from the other processing or the standby state to the command transmission mode for the non-contact IC card. By sending a command,
The received response signal from the non-contact IC card is processed by the received signal detection unit 6 and transmitted to the central processing unit 5.

FIG. 2 is a detailed view of the comparison section 4 in FIG. Since the signals to be compared are both AC, an absolute value circuit is provided in the preceding stage. The next stage is provided with an inverting differential amplifier circuit that compares the two signals and outputs an output proportional to the difference. In order to prevent malfunction due to a momentary change, an integrating circuit having a self-discharge resistor is provided at the next stage. The final stage is provided with a comparator circuit for detecting that there is a certain level of distortion.

FIG. 3 shows an example of the absolute value circuit in FIG. While the input is AC, the output has a full-wave rectified waveform.

[0009]

As is apparent from the above description, in a non-contact IC card or tag supplied with power from a carrier wave of a non-contact IC card reader / writer, a carrier wave (non-modulated) is normally transmitted. , Non-contact I
By automatically detecting the approach of C or the tag by the change in the carrier output waveform, the non-contact IC card reader / writer and the host computer can concentrate on other processes during that time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of a contactless IC card reader according to an embodiment of the present invention.

FIG. 2 is a detailed circuit diagram of a comparison unit in the circuit configuration diagram according to the embodiment of the present invention;

FIG. 3 is an absolute value circuit diagram

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Signal supply part 3 Transmission signal detection part 4 Comparison part 5 Central processing part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C005 MA22 TA22 5B058 CA17 CA22 KA02 KA04 KA13 YA20

Claims (4)

[Claims] 1. An antenna for transmitting and receiving signals to and from a non-contact information carrier, a signal supply unit for supplying a signal transmitted from the antenna, and a transmission signal detection unit for detecting a signal transmitted from the antenna. A comparison unit for comparing a signal supplied from the signal supply unit with a signal detected by the transmission signal detection unit, wherein the comparison unit detects the signal supplied from the signal supply unit and the transmission signal detection A non-contact information carrier reader, comprising: an information signal transmitting unit that transmits an information signal to be transmitted from the antenna to the non-contact carrier when a difference signal from a signal detected by the unit is recognized. 2. An antenna for transmitting and receiving signals to and from a non-contact carrier, a signal supply unit for supplying a fundamental wave of a signal transmitted from the antenna, and a signal waveform for detecting a signal waveform transmitted from the antenna. A detection unit, and a comparison unit that compares a basic waveform of the signal supplied from the signal supply unit with a signal waveform detected by the signal waveform detection unit, and the comparison unit detects the signal waveform by the signal waveform detection unit. A non-contact information carrier reader comprising an information signal transmitting unit for transmitting an information signal to be transmitted from the antenna to the non-contact carrier when a signal waveform obtained is distorted as compared with the fundamental wave. 3. An antenna for transmitting and receiving signals to and from a non-contact information carrier, a signal supply unit for supplying a signal transmitted from the antenna, and a transmission signal detection unit for detecting a signal transmitted from the antenna. A comparison unit that compares a signal supplied from the signal supply unit with a signal detected by the transmission signal detection unit, and an information signal transmission unit that transmits an information signal transmitted from the antenna to the non-contact carrier. A central processing unit, and when the comparison unit does not detect a difference signal between the signal supplied from the signal supply unit and the signal detected by the transmission signal detection unit, the central processing unit is in a standby state. Non-contact information carrier reader to hold. 4. An antenna for transmitting / receiving a signal to / from a non-contact carrier, a signal supply unit for supplying a fundamental wave of a signal transmitted from the antenna, and a signal waveform for detecting a signal waveform transmitted from the antenna A detection unit, a comparison unit that compares a basic waveform of a signal supplied from the signal supply unit with a signal waveform detected by the signal waveform detection unit, and transmits an information signal to be transmitted from the antenna to the non-contact carrier. A non-contact information carrier having a central processing unit provided with an information signal transmitting unit for performing the processing, and when the distortion of the signal detected by the transmission signal detecting unit is not detected in the comparing unit, the central processing unit is kept in a standby state. leader.