JPH11184987A - Non-contact ic card reader/writer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact IC card reader/writer that can attain cost reduction without requiring a dedicated sensor for IC card detection and can precisely detect the non-contact IC card. SOLUTION: A non-contact IC card reader/writer 30 is equipped with a demodulating/modulating circuit 12, a constant current circuit 13, an output transistor 14, a matching circuit 15, a coupling coil 16, a sub-carrier amplifier circuit 17, a sub-carrier detection circuit 32 for detecting a sub-carrier of a signal transmitted through the coupling coil from a non-contact IC card 2 and a control circuit 31 for detecting insertion of the non-contact IC card 2 from the detected sub-carrier; and detects the IC card insertion by having the sub- carrier detection circuit 32 detect the sub-carrier.

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 reader / writer, and more particularly to an improvement in an IC card detection method in a non-contact ΙC card reader / writer.

[0002]

2. Description of the Related Art An IC card is used by encapsulating an LSI chip in a conventional card, and various methods have been realized according to applications. The non-contact IC card has no problems such as poor contact, and can be used in various fields such as places with poor environment. Some non-contact IC cards use light or radio waves as transmission / reception means, and the electromagnetic coupling method is being put into practical use in terms of cost. Also, standardization is being promoted by the ISO (International Organization for Standardization) (ISO 10536, 1
4443).

[0003] As a conventional non-contact IC card reader / writer for reading / writing this kind of non-contact IC card, for example, there is one shown in Figs. In addition,
The expression “reader / writer” described below includes one having both reading and writing functions simultaneously and one having both functions independently.

FIG. 11 is a schematic diagram showing an external configuration of a non-contact IC card reader / writer.

In FIG. 11, a non-contact IC card reader / writer comprises a card reader / writer main body 1 and a non-contact IC card reader / writer.
C card 2.

At the top of the card reader / writer body 1,
A recess 3 for inserting the non-contact IC card 2 and guiding it to a readable / writable position is formed, and a photo interrupter 4 (card) for detecting the insertion of the non-contact IC card 2 is provided on the inner side surface of the recess 3. Detection sensor) is installed.

The photo-interrupter 4 is a photoelectric sensor that detects that the non-contact IC card 2 is inserted by blocking light, and detects that the card is mounted at a predetermined position by a photoelectric change due to shading. This photo interrupter 4
Alternatively, a proximity sensor sensitive to metal or synthetic resin may be provided to detect that the card has approached a predetermined position.

FIG. 12 is a block diagram showing a circuit configuration of a reader / writer part of the non-contact IC card reader / writer.

In FIG. 12, a non-contact IC card reader / writer comprises a control circuit 11, a modulation / demodulation circuit 12, a constant current circuit 13, an output transistor 14, a matching circuit 15,
The contactless IC card 2 includes a coupling coil 16, a subcarrier amplifier circuit 17, and a photointerrupter 4. The non-contact IC card 2 includes a coupling coil 5 that couples to the coupling coil 16 by electromagnetic induction.

The control circuit 11 controls the operation of the card reader / writer. The control circuit 11 reads out unique information and writes new unique information to the non-contact IC card 2 electromagnetically coupled through the coupling coil 16. I do.

The modulation / demodulation circuit 12 modulates data transmitted to the IC card and demodulates data transmitted from the IC card to the reader.

The constant current circuit 13 limits the current supplied to the IC card and supplies a normal value current to the IC card.

The output transistor 14 is a transistor for switching a signal to be sent to the IC card.

The matching circuit 15 matches the signal switched by the output transistor 14 with the coupling coil 16. The matching circuit 15 approximates a rectangular wave signal switched by the output transistor 14 to a sine wave and impedance-couples the signal. The loss in the coil 16 is reduced.

The coupling coil 16 is coupled to the coupling coil 5 of the non-contact ΔC card 2 by electromagnetic induction, and operates as an antenna for supplying power to the IC card, transmitting a signal, and receiving a signal from the IC card.

The subcarrier amplifying circuit 17 is a non-contact IC
The subcarrier signal transmitted from the card 2 through the coupling coil 16 is amplified and converted into a signal that can be demodulated by the demodulation unit of the modulation / demodulation circuit 12.

The non-contact ΔC card 2 operates with the power transmitted from the coupling coil 16, and transmits and receives data using the coupling coil 5. The contactless $ C card 2 has a function of storing information, and reading and writing this information is a function of the contactless IC card reader / writer.

That is, the coupling coil 5 is a coil antenna for receiving a resonance frequency for transmitting power transmitted from the coupling coil 16 of the card read / writer section, and a resonance capacitor is connected in parallel. L of coupling coil 5
And a resonance capacitor C, a resonance circuit is formed. When a resonance frequency is transmitted from the card read / writer unit, a resonance voltage is generated at both ends of the resonance capacitor.
A rectifier circuit for rectifying the power supply resonance frequency generated at both ends of the resonance capacitor and converting it to DC power is provided inside the non-contact 等 C card 2. Operated by supplied power.
In addition, a nonvolatile memory such as an EEPROM that does not require power for backup is used as the internal memory.

The information from the non-contact ΔC card 2 is transmitted via the coupling coil 5 to the coupling coil 16 of the card reader / writer unit.
Sent to.

When the non-contact IC card 2 is inserted due to the interruption of light, the photo interrupter 4 detects the insertion of the card by blocking the infrared rays by the card, and outputs a detection signal to the control circuit 11.

The control circuit 11 detects the insertion of the non-contact IC card 2 based on the detection signal from the photo interrupter 4, and starts the card read / write operation.

As described above, the conventional non-contact IC card reader / writer detects the insertion of the IC card by installing the photo interrupter 4 (card detection sensor). When the insertion of the IC card is detected, the non-contact IC
The power of the card reader / writer is completely turned on.
That is, in a configuration in which the non-contact IC card reader / writer is always operated without using the card detection method as described above, not only the power consumption is increased, but also unnecessary electromagnetic waves are continuously radiated to the outside. Will be. In particular, in the case of a non-contact IC card reader / writer driven by a battery, power saving is important. Therefore, as described above, it is detected that the IC card is inserted, and the IC card is detected.
Activate the reader / writer only when a card is inserted.

[0023]

However, such a conventional non-contact IC card reader / writer has a configuration in which the insertion of an IC card is detected using a dedicated sensor. There were the following issues.

That is, a dedicated sensor and a sensor circuit are required for detecting the insertion of the IC card, and there is a problem that the cost is increased.

Further, since the photointerrupter detects an IC card by detecting the interruption of infrared rays, there is also a problem that a target non-contact IC card cannot be distinguished from other cards or foreign substances. there were.

Further, there are problems that it is difficult to secure a space for installing a dedicated sensor and to make the entire device thinner, and that the operability is poor because the IC card must be completely inserted to a predetermined position. Was.

The present invention provides a non-contact IC card reader / writer which can reduce the cost without requiring a dedicated sensor for detecting an IC card and can accurately detect the corresponding non-contact IC card. The purpose is to:

[0028]

A non-contact IC according to the present invention.
A card reader / writer is a non-contact IC card reader / writer that transmits and receives data by electromagnetic coupling of coils and reads and writes data of a non-contact IC card.
Sub-carrier detection means for detecting a sub-carrier of a signal transmitted from a C card through a coupling coil, and non-contact IC card detection means for detecting insertion of a non-contact ΔC card from the detected sub-carrier. And

A non-contact IC card reader / writer according to the present invention is a non-contact IC card reader / writer for transmitting / receiving data by electromagnetic coupling of coils and reading / writing data from / to the non-contact IC card. A frequency component detecting means for detecting a specific frequency component of a signal transmitted through the coil, and a non-contact IC card detecting means for detecting insertion of a non-contact ΔC card from the detected frequency component.

[0030] In the non-contact IC card reader / writer according to the present invention, the subcarrier detecting means may detect the subcarrier by an intermittent operation.

The subcarriers may be phase-modulated and used for data transmission.

In the contactless IC card reader / writer according to the present invention, the subcarrier detecting means may detect the subcarrier by synchronous detection. Further, the contactless IC card reader / writer may include a PLL. In addition, the sub-carrier may be detected by synchronous detection using a PLL.

In the contactless IC card reader / writer according to the present invention, the subcarrier detecting means may detect the subcarrier without performing synchronous detection.

In the non-contact IC card reader / writer according to the present invention, the frequency component detecting means may detect a specific frequency component by an intermittent operation.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The non-contact IC card reader / writer according to the present invention can be applied to a card reader / writer for an ID card such as a commuter pass or a tag.

First Embodiment FIG. 1 is a diagram showing an external configuration of a non-contact IC card reader / writer according to a first embodiment of the present invention.

In FIG. 1, reference numeral 21 denotes a card reader / writer main body, in which the reader / writer circuit shown in FIG. 2 is stored.

On the upper part of the card reader / writer body 21, there are provided a lamp 22 for indicating a status such as an energized state and a read / write state, and a concave portion 23 for guiding a non-contact IC card to a position where it can be read / written. is set up.

The recess 23 has an opening 24 which is larger than the non-contact IC card so that the non-contact IC card can be easily attached to and detached from the side and top surfaces.
And a slope 25 inclined toward the card mounting surface.
The bottom surface of the recess 23 is gently inclined in the depth direction in order to facilitate insertion of the non-contact IC card in the depth direction and to prevent the non-contact IC card from dropping off after being mounted. Further, unlike the conventional example, there is no card detection sensor unit such as a photo interrupter for detecting the insertion of the non-contact IC card, and the card is not consciously inserted when the card is inserted.

With such a configuration, the non-contact IC card can be easily inserted from either the side surface or the top surface of the card reader / writer body 21, and the operability can be improved.

FIG. 2 is a block diagram showing a circuit configuration of a reader / writer portion of the non-contact IC card reader / writer according to the first embodiment. In the description of the non-contact IC card reader / writer according to the present embodiment, the same components as those of the non-contact IC card reader / writer shown in FIG.

In FIG. 2, a non-contact IC card reader
The writer 30 includes a control circuit 31 (contactless IC card detection means), a modulation / demodulation circuit 12, a constant current circuit 13, an output transistor 14, a matching circuit 15, a coupling coil 16, a subcarrier amplification circuit 17, and a subcarrier detection circuit 32.
(Subcarrier detecting means). Reference numeral 2 denotes a non-contact IC card which is read / written by a non-contact IC card reader / writer 30. The non-contact IC card 2 includes a coupling coil 5 which is coupled to a coupling coil 16 by electromagnetic induction.

The control circuit 31 is a control unit for controlling the operation of the card reader / writer, and reads out unique information and writes new unique information to the non-contact IC card 2 which is electromagnetically inductively coupled via the coupling coil 16. In addition, the insertion of the non-contact IC card 2 is detected based on the IC card detection output from the subcarrier detection circuit 32, and the read / write operation of the IC card is started.

The modulation / demodulation circuit 12 modulates data transmitted to the IC card and demodulates data transmitted from the IC card to the reader.

The constant current circuit 13 limits the current supplied to the IC card, and supplies a normal value current to the IC card. The current value supplied to the IC card is standardized by ISO according to the type of the IC card.

The output transistor 14 is a transistor for switching a signal to be sent to the IC card.

The matching circuit 15 matches the signal switched by the output transistor 14 with the coupling coil 16. The matching circuit 15 approximates a rectangular wave signal switched by the output transistor 14 to a sine wave, and performs impedance matching to couple the signal. The loss in the coil 16 is reduced.

The coupling coil 16 is coupled to the coupling coil 5 of the non-contact ΔC card 2 by electromagnetic induction, and operates as an antenna for supplying power to the IC card, transmitting a signal, and receiving a signal from the IC card.

The subcarrier amplification circuit 17 is a non-contact IC
The subcarrier signal transmitted from the card 2 through the coupling coil 16 is amplified and converted into a signal that can be demodulated by the demodulation unit of the modulation / demodulation circuit 12.

The subcarrier detection circuit 32 has a function of determining whether or not the signal amplified by the subcarrier amplification circuit 17 is a subcarrier, and transmitting the detection of the subcarrier to the control circuit 31.

The non-contact ΔC card 2 operates with the power transmitted from the coupling coil 16, and transmits and receives data using the coupling coil 5. The contactless $ C card 2 has a function of storing information, and reading and writing this information is a function of the contactless IC card reader / writer 30. Information from the non-contact ΔC card 2 is transmitted to the coupling coil 16 of the card read / writer unit via the coupling coil 5.

As described above, the non-contact IC card reader / writer 30 uses the subcarrier detection circuit for detecting that the signal amplified by the subcarrier amplification circuit 17 is a subcarrier without using a dedicated card detection sensor. The subcarrier detection circuit 32 detects that an IC card has been inserted.

Hereinafter, the non-contact IC configured as described above
The operation of the card reader / writer 30 will be described.

FIG. 3 is a timing chart for explaining the operation of the non-contact IC card reader / writer. In FIG. 3, a, b, and c correspond to the signals a, b, and c of the respective units in FIG.

First, the non-contact IC card reader / writer 3
When the power of 0 is turned on, the circuit is initialized, and the control device 31 starts operating. In addition, a lamp 22 indicating an energized state at the top of the card reader / writer main body 21 is turned on.

The control circuit 31 sends a signal to the modulation / demodulation circuit 12, and the modulation / demodulation circuit 12 generates a signal corresponding to the signal.
The output transistor 14 is switched. A constant current circuit 13 is connected to the output transistor 14, and a predetermined current is supplied to the matching circuit 15 by a switching operation of the output transistor 14.

The signal generated by the switching of the output transistor 14 passes through the matching circuit 15 and is sent to the coupling coil 16. In the matching circuit 15, a signal close to a rectangular wave switched by the output transistor 14 is approximated to a sine wave, and impedance matching is performed to reduce a loss in the coupling coil 16. The output signal from the matching circuit 15 is shown by the sine wave portion in FIG. 3a. That is, FIG. 3A is a waveform applied to the coupling coil 16, and is a waveform centered on a spectrum of a frequency sufficiently higher than a subcarrier including a subcarrier frequency component (a broken line portion in FIG. 3A).

Upon receiving a signal from the coupling coil 16, the non-contact IC card 2 starts operating using the signal as a power source.

When the non-contact ２C card 2 starts operating and reaches a stable state, the non-contact IC card 2 generates a subcarrier (broken line in FIG. 3A). This subcarrier is sent to the subcarrier amplifier circuit 17 through the coupling coil 16.

The subcarrier amplification circuit 17 extracts and amplifies only the subcarrier component in the signal, and
The second subcarrier signal is sent to the second demodulation unit. FIG.
This is a subcarrier separated from the subcarrier signal indicated by a, and such a waveform is output from the subcarrier amplifier circuit 17 when the non-contact IC card 2 starts operating.

The demodulation section of the modulation / demodulation circuit 12 demodulates the subcarrier signal sent from the subcarrier amplification circuit 17 and outputs demodulated data.

On the other hand, the subcarrier signal output from the subcarrier amplification circuit 17 is
Also sent to. When detecting the presence of the subcarrier, the subcarrier detection circuit 32 notifies the control circuit 31 of the subcarrier detection. FIG. 3C shows an output waveform of the subcarrier detection circuit 32. When a subcarrier is detected, the voltage changes. In FIG. 3c, when a subcarrier is detected, Lo
The level changes from the w level to the high level.

By this operation, the control circuit 31 recognizes the existence of the subcarrier. The detection of the subcarrier indicates that the non-contact IC card 2 has been inserted into the card reader / writer body 21. Therefore, when recognizing the subcarrier, the control circuit 31 starts reading data from the non-contact IC card 2 and writing data to the non-contact IC card 2.

As described above, the non-contact IC card reader / writer 30 according to the first embodiment includes a modulation / demodulation circuit 12, a constant current circuit 13, an output transistor 14, a matching circuit 15, a coupling coil 16, a subcarrier amplifier, A circuit 17, a subcarrier detection circuit 32 for detecting a subcarrier of a signal transmitted from the noncontact IC card 2 through the coupling coil 16, and a noncontact ΔC from the detected subcarrier.
Since the control circuit 31 for detecting the insertion of the card 2 is provided, and the subcarrier is detected by the subcarrier detection circuit 32, the insertion of the IC card is detected. Therefore, the following effects can be obtained.

(1) Since a dedicated sensor such as a photo interrupter for detecting a card is not required, the cost can be reduced. That is, the subcarrier detection circuit 32
Are cheaper than dedicated sensors and can be made cheaper. In addition to reducing costs by not using a dedicated sensor, it is possible to avoid the trouble of adjusting when installing a dedicated sensor as a separate system, failure of the dedicated sensor, and deterioration of reliability due to aging. Will be possible.

(2) Further, since only the assumed non-contact IC card is not detected, no subcarrier is generated even if a card other than the assumed non-contact IC card is inserted, and no erroneous detection is performed. .

(3) Further, as is apparent from a comparison between FIG. 1 and FIG. 11, since the card reader / writer body does not have a card detection sensor section, the card is inserted with the card section being conscious of the sensor section. Never. For this reason, the non-contact IC card can be easily inserted from any position of the side surface or the top surface of the card reader / writer main body 21,
Operability can be improved. Further, the size and thickness of the entire device can be easily reduced.

Second Embodiment The circuit configuration of a non-contact IC card reader / writer according to a second embodiment of the present invention is the same as that of the non-contact IC card reader / writer shown in FIG. The second control circuit 31 is different in that it has a function of intermittently generating a signal. Further, in this case, it is possible to arbitrarily set a signal generation interval based on a signal input to the control circuit 31 by a switch or the like.

FIG. 4 is a timing chart for explaining the operation of the non-contact IC card reader / writer according to the second embodiment, and shows signal waveforms during operation. Note that a, b, and c in the figure correspond to the signals a, b, and c of the respective units in FIG.

As shown in FIG. 4, the control circuit 31
The signal waveform applied to the coupling coil 16 is intermittent.
As a result, the time during which the non-contact IC card reader / writer is operating and the time during which it is stopped alternately occur.
The time interval can be changed by a signal input to the control circuit 31 by a switch or the like.

As described above, the non-contact IC card reader / writer according to the second embodiment includes the control circuit 31
However, since the state in which a signal is generated is intermittently operated, the power consumption during standby until a card is detected can be reduced by setting the operation of the card reader / writer as an intermittent operation. In addition, it is possible to reduce the effect of other devices on the electromagnetic wave generated from the coil.

In the first and second embodiments, the card is detected by using the detection of subcarriers. However, the present method can be used in a card reader / writer system that does not use subcarriers. The effect can be obtained.

In a system that does not use subcarriers, data is transmitted by directly superimposing data of a signal transmitted from the reader / writer to the card on a signal transmitted from the card to the reader / writer. However, even in this case, the signal component of the data is transmitted in a specific frequency bandwidth. Therefore, in a system that does not use subcarriers, by changing the frequency characteristic of the subcarrier amplifier circuit 17 to match the frequency band of the data,
The method can be used.

In the first and second embodiments described above, the insertion of the non-contact IC card can be detected by using the subcarrier detection circuit 32. Next, a specific configuration example of subcarrier detection and its operation will be described in detail with reference to a third embodiment. The third embodiment is an embodiment showing an example in which subcarriers are phase-modulated and used for data transmission.

Third Embodiment FIG. 5 is a circuit diagram showing a configuration of a non-contact IC card reader / writer according to a third embodiment of the present invention. In the description of the non-contact IC card reader / writer according to the present embodiment, the same components as those of the non-contact IC card reader / writer shown in FIG.

In FIG. 5, a non-contact IC card reader
The writer 40 includes a control circuit 31, a modem circuit 12, a constant current circuit 13, an output transistor 14, and a matching circuit 1.
5, a coupling coil 16, a subcarrier amplification circuit 17, a binarization circuit 41, and a subcarrier detection circuit 32, and a configuration in which the binarization circuit 41 is added to the non-contact IC card reader / writer shown in FIG. ing.

FIG. 6 is a block diagram showing in detail the configuration of the demodulation section of the modulation / demodulation circuit 12. As shown in FIG.

In FIG. 6, the demodulation section of the modulation / demodulation circuit 12 includes a phase change detector 51 for comparing the phase of the carrier synchronization signal with the subcarrier, and an initial state for determining whether the data in the initial state is 0 or 1. And a phase determination circuit 52.

Further, the carrier change signal e is input to the phase change detector 51 from the subcarrier detection circuit 32. The carrier synchronization signal e is a signal that serves as a reference phase for extracting demodulated data from the phase-modulated subcarrier.

The phase change detector 51 compares the carrier synchronization signal (FIG. 5E) from the subcarrier detection circuit 32 with the phase of the subcarrier, and when the phase of the subcarrier changes, the output of the phase change detector 51 is inverted. I do. The output of the phase change detector 51 only fluctuates for each phase change, and it is necessary to separately determine whether the initial data is 1 or 0. Therefore, an initial phase determination circuit 52 is provided, and the initial phase determination circuit 52 determines whether the data in the initial state is 0 or 1, and demodulates accurate data.

FIG. 7 is a block diagram showing the configuration of the subcarrier detection circuit 32.

In FIG. 7, a subcarrier detection circuit 32
Is composed of a phase comparator 61, a delay adjuster 62, a reference signal generator 63, a filter 64, and a filter 65.

The phase comparator 61, the delay adjuster 62, the reference signal generator 63 and the filter 64 as a whole
Construct L (Phase Locked Loop).

The phase comparator 61 compares the square wave from the reference signal generator 63 with the square wave obtained by binarizing the subcarrier. When the subcarrier and the signal from the delay adjuster 62 have different phases, the phase comparator 61 Give a signal. When the phases completely match, a continuous Low signal is obtained.

The delay adjuster 62 adjusts the phase of the reference signal generator 63 so that the signal generated by the reference signal generator 63 matches.

The reference signal generator 63 generates a square wave at the same frequency as the subcarrier.

The filter 64 converts the comparison result signal output from the phase comparator 61 so that it can be input to the delay adjuster 62.

When an intermittent signal is output from the phase comparator 61, the filter 65 outputs a Low level signal (hereinafter, referred to as a low level signal).
The phase comparator 61 outputs a High level (hereinafter, simply referred to as High) when continuous Low is output from the phase comparator 61.

Hereinafter, the non-contact IC configured as described above will be described.
The operation of the card reader / writer 40 will be described.

FIG. 8 shows a non-contact IC card reader / writer 4
FIG. 6 is a timing chart for explaining an operation of a zero.
In the drawings, b, d, f, e, and g correspond to the signals b, d, f, e, and g of the respective units in FIGS. 5 and 7, respectively. Note that a, b, and c in FIG. 5 are the same signals as the signals a, b, and c in FIG. 2 and FIG.

The operation from the start of the operation of the non-contact ΔC card 2 to the generation of subcarriers and the transmission of the generated subcarriers to the subcarrier amplification circuit 17 through the coupling coil 16 are the same as those in the first embodiment. is there.

The subcarrier amplification circuit 17 extracts and amplifies only the subcarrier component in the signal, and sends the extracted subcarrier (see FIG. 8B) to the binarization circuit 41.

The binarization circuit 41 binarizes the subcarrier shown in FIG. 8B and outputs a rectangular wave as shown in FIG. 8D.

The signal obtained by binarizing the subcarrier (see FIG. 8D) is output to the demodulation section (FIG. 6) and the subcarrier detection circuit 32 (FIG. 7) of the modulation / demodulation circuit 12, and the modulation / demodulation circuit 12
The following operation is performed by the demodulation unit and the subcarrier detection circuit 32.

Operation of Demodulation Unit (FIG. 6) of Modulation / Demodulation Circuit 12 The phase change detector 51 determines the phase of the carrier synchronization signal (FIG. 8E) and the phase of the subcarrier (FIG. 8D) from the subcarrier detection circuit 32 as the reference phase. If there is a change in the phase of the subcarrier, the output is inverted and the demodulated data is extracted from the subcarrier that has been phase modulated. Here, whether the initial data is 1 or 0 is determined by the initial phase determination circuit 52.
And accurate data is demodulated.

Operation of Subcarrier Detection Circuit 32 (FIG. 7) The reference signal generator 63 in the subcarrier detection circuit 32 generates a reference signal having the same frequency as the subcarrier. The reference signal generated by the reference signal generator 63 is shown by a square wave in FIG. 8F, and is supplied to the phase comparator 61 through the delay adjuster 62. This reference signal has the same frequency as the subcarrier (FIG. 8d), but has a different phase from the subcarrier as shown in FIGS. 8d and f because it is generated by an oscillator different from the subcarrier. .

The signal d obtained by binarizing the subcarrier is input to a phase comparator 61, and the phase comparator 61
2 and a square wave obtained by binarizing the subcarrier, and outputs an error signal corresponding to the phase difference to the filters 64 and 65. The filter 64 converts the signal from the phase comparator 61 so that it can be input to the delay adjuster 62. The delay adjuster 62 adjusts the phase of the reference signal generator 63 based on the output of the filter 64 such that the signal generated by the reference signal generator 63 matches. FIG. 8e shows the reference signal through the delay adjuster 62.

When the filter 64 receives an error signal indicating that the phase is shifted from the phase comparator 61, the filter 64 sends a phase adjustment signal to the delay adjuster 62 based on the error information.

By repeating this operation, the phase of the signal output from the delay adjuster 62 (FIG. 8E) and the phase of the binarized subcarrier (FIG. 8D) gradually match. If the phases match completely, only Low is output from the phase comparator 61.

As described above, the phase comparator 61 compares the square wave from the reference signal generator 63 with the square wave obtained by binarizing the subcarriers.
The phase of the reference signal generator 63 is adjusted so that the quantified square wave matches the signal generated by the reference signal generator 63. The comparison result output from the phase comparator 61 is shown in FIG.
The filter 64 converts the signal g so that it can be input to the delay adjuster 62.

The phase comparator 61 outputs a Low signal when the phase of the subcarrier (FIG. 8D) and the signal (FIG. 8E) from the delay adjuster 62 are different, as shown in FIG. Then, it becomes a continuous Low signal. That is, the output of the phase comparator 61 is an intermittent signal until the phase of the subcarrier matches the reference signal, and becomes continuous low when the phase of the subcarrier matches the phase of the reference signal.

On the other hand, the output of the phase comparator 61 is
5 and the output of the filter 65 becomes the card detection output (FIG. 8h). The filter 65 outputs Low when the intermittent signal is output from the phase comparator 61 as shown in FIG. 8H, and outputs High when continuous Low is output from the phase comparator 61. I do.
Actually, there is a phase match in the phase comparator 61, and the card detection output becomes High after a lapse of the delay time due to the filter 65 after the continuous Low continues.

By operating as described above, when a subcarrier is detected and its phase can be captured, it can be determined that the card has been detected.

As described above, the non-contact IC card reader / writer 40 according to the third embodiment includes a modulation / demodulation circuit 12, a constant current circuit 13, an output transistor 14, a matching circuit 15, a coupling coil 16, a subcarrier amplifier. The circuit 17, the binarization circuit 41, the subcarrier detection circuit 32 for detecting the subcarrier of the signal transmitted from the noncontact IC card 2 through the coupling coil 16, the insertion of the noncontact ΔC card 2 is detected from the detected subcarrier. Control circuit 3
1, the subcarrier detection circuit 32 includes a phase comparator 61, a delay adjuster 62, a reference signal generator 63, and filters 64 and 65 which constitute a PLL, and detects the phase-modulated subcarrier by synchronous detection. As a result, since the card insertion is detected, the cost can be reduced without the need for a dedicated sensor for detecting the card, as in the first embodiment. The card can be detected with high accuracy.

In particular, when compared with a conventional device that performs phase detection by synchronous detection, the conventional device also has most of the circuits of the subcarrier detector 32 shown in FIG. However, it did not have the filter 65 and could not extract the subcarrier detection output. Therefore, in the present embodiment, not only is a dedicated sensor for detecting a card or its sensor circuit unnecessary, but also the configuration itself of the subcarrier detection circuit 32 can be simply changed from the conventional device, and a significant increase in the number of parts is required. It has an excellent effect that it can be easily implemented without inviting.

In each of the above embodiments, the subcarriers are
This is an example in which the present invention is applied to a subcarrier detection circuit 32 that performs synchronous detection. However, the present invention may be applied to a circuit that detects subcarriers without performing synchronous detection. A case where subcarriers are detected without synchronous detection will be described with reference to a fourth embodiment.

Fourth Embodiment FIG. 9 is a block diagram showing a configuration of a subcarrier detection circuit of a non-contact IC card reader / writer according to a fourth embodiment of the present invention. The configuration other than the subcarrier detection circuit shown in FIG. 9 can adopt the same configuration as the circuit of the non-contact IC card reader / writer shown in FIG.

In FIG. 9, subcarrier detection circuit 70
(Subcarrier detecting means) includes a bandpass filter 7
1, an integrating circuit 72 and a comparator 73.

The band-pass filter 71 removes signals of frequency components other than subcarriers.

The integrating circuit 72 is composed of, for example, an RC circuit, and integrates a DC voltage obtained by rectifying a subcarrier.

The comparator 73 compares the output of the integration circuit 72 with a reference value, and determines that the subcarrier has been detected when the output of the integration circuit 72 is equal to or greater than a predetermined value.

The integrating circuit 71 and the comparator 73
There are a method of configuring with an analog circuit and a method of configuring with a digital circuit.

Hereinafter, the non-contact IC configured as described above will be described.
The operation of the subcarrier detection circuit 70 of the card reader / writer will be described.

FIG. 10 is a timing chart for explaining the operation of the subcarrier detection circuit 70, and shows signal waveforms during the operation. Note that a, b, and c in FIG.
Respectively correspond to the signals a, b, c of the respective sections.

For example, in FIG. 2, when the subcarrier amplification circuit 17 extracts and amplifies only the subcarrier component in the signal and sends the extracted subcarrier to the subcarrier detection circuit 70, the band-pass filter 71 The signal of the frequency component other than the carrier is removed.

In the integration circuit 72, the subcarrier (FIG. 10)
The DC voltage obtained by rectifying a) is integrated to output a signal shown in FIG. 10B. This integration circuit 72 is used to determine that a subcarrier has been detected when the subcarriers have continued for a predetermined time or more. Further, a malfunction due to noise can be prevented by the integration circuit 72.

As shown in FIGS. 10B and 10C, the comparator 73 determines that the subcarrier has been detected when the output of the integration circuit 72 has exceeded a predetermined value, and outputs a subcarrier detection signal (High).
Level signal).

As described above, the non-contact IC card reader / writer according to the fourth embodiment includes the subcarrier detection circuit 7
0 is composed of a band-pass filter 71, an integrating circuit 72, and a comparator 73, and the sub-carriers are detected without synchronous detection. Therefore, the first embodiment is also applied to an apparatus for detecting sub-carriers without synchronous detection. The same effect as in the embodiment can be obtained.

As in the second embodiment, in this embodiment, the operation of the card reader / writer is set to the intermittent operation, so that the power consumption during standby until the card is detected and the coil consumption are reduced. It is also possible to reduce the generated electromagnetic waves.

As described above, the non-contact IC card reader / writer according to each of the above-described embodiments can detect an IC card accurately at low cost while having a simple circuit configuration. It has an excellent feature that it can be applied to a read / write device for an IC card.

In the above embodiment, the device applied to the card reader / writer of the ID card such as a commuter pass or a tag has been described. However, if the device is an IC card read / write device which transmits and receives data by electromagnetic coupling of a coil. It goes without saying that the present invention can be applied to any system and standard. In addition, for convenience of explanation, the name “card reader / writer” is used, but it is a matter of course that a read only device or a write only device such as a commuter pass may be used.

The subcarriers have the waveforms shown in FIGS. 3, 4 and 10, but are of course not limited thereto, and may have any form capable of demodulating a signal transmitted from an IC card through a coupling coil. Subcarriers. Needless to say, any method may be used for signal detection.

Further, the types and number of the various circuits and filters constituting the non-contact IC card reader / writer and the subcarrier detection circuit, the connection state, and the like are not limited to the above embodiments.

[0124]

The contactless IC card reader according to the present invention
The writer includes a subcarrier detecting means for detecting a subcarrier of a signal transmitted from the noncontact IC card through the coupling coil, and a noncontact IC card detecting means for detecting insertion of a noncontact ΔC card from the detected subcarrier. With this configuration, the price can be reduced without requiring a dedicated sensor for detecting the non-contact IC card, and the corresponding non-contact IC card can be detected with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing an external configuration of a non-contact IC card reader / writer according to a first embodiment to which the present invention is applied.

FIG. 2 is a block diagram showing a circuit configuration of a reader / writer part of a driver of the contactless IC card reader / writer.

FIG. 3 is a timing chart for explaining the operation of the non-contact IC card reader / writer.

FIG. 4 is a timing chart for explaining an operation of a non-contact IC card reader / writer according to a second embodiment to which the present invention is applied.

FIG. 5 is a circuit diagram showing a configuration of a non-contact IC card reader / writer according to a third embodiment to which the present invention is applied.

FIG. 6 is a block diagram showing in detail a configuration of a demodulation unit of a modulation / demodulation circuit of the contactless IC card reader / writer.

FIG. 7 is a block diagram showing a configuration of a subcarrier detection circuit of the contactless IC card reader / writer.

FIG. 8 is a timing chart for explaining the operation of the subcarrier detection circuit of the contactless IC card reader / writer.

FIG. 9 is a block diagram illustrating a configuration of a subcarrier detection circuit of a non-contact IC card reader / writer according to a fourth embodiment to which the present invention is applied.

FIG. 10 is a timing chart for explaining the operation of the subcarrier detection circuit of the contactless IC card reader / writer.

FIG. 11 is a schematic diagram showing an external configuration of a conventional non-contact IC card reader / writer.

FIG. 12 is a block diagram showing a circuit configuration of a reader / writer portion of a conventional non-contact IC card reader / writer.

[Explanation of symbols]

2 Non-contact IC card, 5, 16 coupling coil, 12
Modulation / demodulation circuit, 13 constant current circuit, 14 output transistor, 15 matching circuit, 17 subcarrier amplifier circuit, 21 card reader / writer body, 30, 40 non-contact IC card reader / writer, 31 control circuit (non-contact IC card detection means ), 32, 70 subcarrier detection circuit (subcarrier detection means), 41 binarization circuit, 5
1 phase change detector, 52 initial phase determination circuit, 61
Phase comparator, 62 delay adjuster, 63 reference signal generator, 64, 65 filters, 71 band pass filter, 72 integrator, 73 comparator

Claims (8)

[Claims] 1. A non-contact IC for transmitting / receiving data by electromagnetic coupling of a coil and reading / writing data of a non-contact IC card.
In a C card reader / writer, a subcarrier detecting means for detecting a subcarrier of a signal transmitted from a noncontact IC card through a coupling coil, and a noncontact IC card for detecting insertion of a noncontact ΙC card from the detected subcarrier A non-contact IC card reader / writer characterized by comprising a detecting means. 2. A non-contact IC for transmitting and receiving data by electromagnetic coupling of a coil to read and write data of a non-contact IC card.
In a C card reader / writer, frequency component detection means for detecting a specific frequency component of a signal transmitted from a non-contact IC card through a coupling coil, and non-contact IC for detecting insertion of a non-contact C card from the detected frequency component A non-contact IC card reader / writer, comprising: card detection means. 3. The non-contact IC card reader / writer according to claim 1, wherein said sub-carrier detection means performs sub-carrier detection by intermittent operation. 4. The non-contact IC card reader / writer according to claim 1, wherein the sub-carrier is phase-modulated and used for data transmission. 5. The non-contact IC card reader / writer according to claim 1, wherein said sub-carrier detecting means detects the sub-carrier by synchronous detection. 6. The non-contact IC card reader / writer according to claim 5, further comprising a PLL, wherein the sub-carrier is detected by synchronous detection using the PLL. 7. The non-contact IC card reader / writer according to claim 1, wherein the subcarrier detection means detects the subcarrier without performing synchronous detection. 8. The non-contact IC card reader / writer according to claim 2, wherein the frequency component detection means detects a specific frequency component by an intermittent operation.