JPH11146580A - Reader-writer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit operation power to a mobile information processing body such as IC card or the like contactlessly by a reader-writer, and power received by the relevant mobile information processing body is uniformized. SOLUTION: At a reader-writer 1, for example, after power from transmitting means constituted with a power transmitting section 12 and a transmitting antenna 11 are transmitted to an IC card, the receiving means constituted of a data receiving section 15 and a receiving antenna 14 receives the signal from the relevant IC card. Then, a receiving level detector section 16 constituting detection means detects the level of the receiving signal, and a transmitting power control section 17 constituting transmitting power adjusting means adjusts power transmitted from the transmitting means in response to the level of the detected received signal, and the power received by the relevant IC card is uniformzed. Also, the date transmitting section 13 transmits data from the transmitting antenna, and a CPU20 controls various processings by using ROM18 and RAM19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reader / writer for transmitting operating power to a mobile information processing body such as an IC card or the like in a non-contact manner, and performing non-contact signal communication with the mobile information processing body. In particular, the present invention relates to a reader / writer that adjusts power transmitted to a mobile information processing body in accordance with a level of a signal received from the mobile information processing body and stabilizes power received by the mobile information processing body.

[0002]

2. Description of the Related Art For example, an IC card formed by embedding a microcomputer chip and a memory chip on a card substrate having a size similar to that of a credit card or the like has been put to practical use in various fields such as finance, distribution, transportation, and medicine. Is planned. In an IC card system using such an IC card, power is transmitted and supplied from a reader / writer to the IC card, and information such as a control code and data is communicated between the reader / writer and the IC card. In power transmission and information communication between a reader / writer and an IC card,
In addition to a contact method in which terminals are brought into contact with each other, a non-contact method in which electromagnetic waves are used is also employed.

FIG. 3 shows an example of an IC card system employing a non-contact method. The IC card system shown in FIG. 1 includes a reader / writer 31 that performs non-contact power transmission and signal communication, and a non-contact IC card 33 that incorporates an IC chip and a coil of an antenna 34 described later. I have. Each of the reader / writer 31 and the IC card 33 has an antenna 3 composed of a coil wound in a rectangular shape or the like.
2 and 34, for example, transmission of power and communication of signals including information and the like are performed by electromagnetic coupling between an antenna 32 provided in a reader / writer 31 and an antenna 34 provided in an IC card 33. It will be described as being performed.

In the reader / writer 31, for example, a high-frequency current is applied to the coil of its own antenna 32 to generate a magnetic flux from the coil, and the antenna of the IC card 33 is generated by electromagnetic induction caused by the magnetic flux thus generated. By inducing a voltage on the IC card 33,
To transmit power and signals to The IC card 33 has, for example, no internal power supply, and starts up and operates using the power received from the reader / writer 31 to operate the reader / writer 3.
Various kinds of processing such as transmission of a response signal to 1 are performed. Transmission of a signal from the IC card 33 to the reader / writer 31 is performed using, for example, a carrier wave that carries transmission power from the reader / writer 31.

Further, the reader / writer 3 is read from the IC card 33.
The signal transmitted to the IC card 1 is received by the antenna 32 provided in the reader / writer 31 using electromagnetic induction or the like, as in the case of the power transmission and the signal transmission from the reader / writer 31 to the IC card 33 described above. In general, a communicable area in which power transmission and signal communication can be performed with the IC card 33 is set in the reader / writer 31, and the communication area between the reader / writer 31 and the IC card 33 is set. Power transmission and signal communication are performed in a state where the IC card 33 exists in the communicable area of the reader / writer 31.

[0006]

However, in the above-described reader / writer, since a constant amount of power is always transmitted from the power transmitting antenna, the reader / writer is provided in the power transmitting antenna and the IC card. The power received by the IC card fluctuates greatly depending on the distance between the antenna and the power receiving antenna. Specifically, for example, as shown in FIG. 4, in the communicable area of the reader / writer 31, the IC card 3 is located relatively far from the reader / writer 31.
In 3a, the received power is relatively small, while in the IC card 33b located at a relatively short distance from the reader / writer 31, the received power is relatively large.

In general, in an IC card system, the usability is improved as the communicable area of the reader / writer is wider. However, for example, in a configuration in which relatively small power is always transmitted from the reader / writer, the reader / writer is located relatively far from the reader / writer. Sufficient operating power cannot be supplied to the IC card, and the communicable area becomes narrow.

On the contrary, for example, in a configuration in which relatively large power is always transmitted from a reader / writer, sufficient power can be supplied to an IC card located relatively far from the reader / writer. An extremely large amount of power may be excessively supplied to the IC card located at a relatively short distance from the reader / writer. For this reason, for example, when an IC card that receives excessive power emits excess power as heat, a large amount of heat is generated, which may destroy an IC circuit or the like inside the IC card. was there. In addition, when excessive power is supplied to the IC card in this way, there is a problem that extra power received by the IC card is wasted.

As described above, the above-described reader / writer always transmits a constant amount of power regardless of the distance between the IC card and the IC card. Cannot be ensured, and stable operation power cannot be supplied to the IC card as described above.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. The present invention transmits operating power to a mobile information processing body such as an IC card or the like in a non-contact manner. When performing signal communication in a non-contact manner, for example, regardless of the magnitude of the distance between the mobile information processing body existing in the communicable area, to stabilize the power received by the mobile information processing body It is an object of the present invention to provide a reader / writer capable of performing the following.

[0011]

In order to achieve the above object, a reader / writer according to the present invention transmits operating power to a mobile information processing body in a non-contact manner, and performs non-contact communication with the mobile information processing body. When performing signal communication, the transmission power is adjusted as follows. That is, when the transmitting means transmits power to the mobile information processing body, the receiving means receives a signal from the mobile information processing body, the detecting means detects the level of the received signal, and the transmission power adjusting means The power transmitted from the transmitting means is adjusted such that the power received by the mobile information processing body is constant according to the detected received signal level.

Therefore, for example, even when the distance between the reader / writer and the mobile information processing body is large and the power received by the mobile information processing body is relatively small, the reader / writer can perform the mobile information processing. Since the power transmitted to the mobile information processing body is increased in response to the level of the signal received from the body being relatively small, sufficient operating power is received by the mobile information processing body Can be ensured. Also, for example, even when the distance between the reader / writer and the mobile information processing body is small and the power received by the mobile information processing body is excessively large, the reader / writer can receive the power from the mobile information processing body. Since the power transmitted to the mobile information processing body is reduced according to the relatively large level of the signal, the power received by the mobile information processing body is suppressed to an appropriate level. Thus, it is possible to prevent the movement information processing body from being damaged.

Here, the adjustment of the transmission power referred to in the present invention includes the adjustment of increasing the transmission power when the level of the signal received from the mobile information processing body is low, and the adjustment of the level of the signal received from the mobile information processing body. In addition to the mode in which both the adjustment for reducing the transmission power when the value is large and the mode in which only one of these adjustments is performed are included. Further, to make the power received by the mobile information processing body constant in the present invention means not only a mode in which the power received by the mobile information processing body is kept at a substantially constant value, but also the power received by the mobile information processing body. The present invention also includes a mode in which the power of the mobile information processing body is maintained at such a level that the mobile information processing body can operate without any trouble. Thus, the constant power in the present invention is a concept that allows a range of power.

Further, the mobile information processing body referred to in the present invention includes:
Not only the IC card described above, but also, for example, a name plate attached to a person, a tag attached to a product or article, an identification plate attached to livestock, or a delivery destination plate attached to parcels of parcel delivery service And a delivery destination plate attached to the container. As described above, in the present invention, various mobile information processing bodies that receive operating power from a reader / writer in a non-contact manner and perform signal communication in a non-contact manner with the reader / writer may be used. The present invention is widely applicable to reader / writers that perform power transmission and signal communication without contact with various types of mobile information processing bodies.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to the drawings. In this example, a case where an IC card is used as the mobile information processing body is shown. FIG. 1 shows an example of an IC card system equipped with a reader / writer 1 according to the present invention. Is provided. In this example, the reader / writer 1
The apparatus includes a transmitting antenna 11 for transmitting power and transmitting a signal including information and the like, and a receiving antenna 14 for receiving a signal from the IC card 2.
Power transmission and signal communication with the IC card 2 are performed using the IC card 1 and the IC card 2.

In this embodiment, the IC card 2 has an antenna 21 for receiving power and transmitting and receiving a signal containing information and the like.
Power transmission and signal communication are carried out with the. In the IC card 2 of this example, for example, a power supply is not provided inside, and activation and various operations are performed by using power received from the reader / writer 1 in a non-contact manner as a power supply. When the transmitted power is received, a response signal is transmitted to the reader / writer 1 using a carrier wave that carries the power transmitted from the reader / writer 1.

The transmitting antenna 11 and the receiving antenna 14 provided in the reader / writer 1 and the antenna 21 provided in the IC card 2 are composed of, for example, coils wound in a rectangular shape. Electromagnetic coupling between the transmission antenna 11 of the reader / writer 1 and the antenna 21 of the IC card 2 causes the transmission of operating power and signals from the reader / writer 1 to the IC card 2 and the reception antenna of the reader / writer 1. 14 and antenna 2 of IC card 2
Signals are transmitted from the IC card 2 to the reader / writer 1 by electromagnetic coupling with the IC card 2. In the reader / writer 1 of the present embodiment, as shown in FIG. 1, power is transmitted from the transmitting antenna 11 with an overlapping portion between the coil surface of the transmitting antenna 11 and the coil surface of the receiving antenna 14. In this state, the coils of the two antennas 11 and 14 are arranged so as to be shifted in parallel so that no power is induced in the receiving antenna 14.

Next, the configuration of the above-described reader / writer 1 and the transmission power adjustment processing performed by the reader / writer 1 will be described in detail. FIG. 2 shows a configuration example of the above-described reader / writer 1 according to the present invention. The reader / writer 1 includes the above-described transmission antenna 11, a power transmission unit 12 for performing power transmission processing, A data transmitting unit 13 for transmitting information such as data and control codes; a receiving antenna 14 as described above; a data receiving unit 15 for receiving and processing information such as data and control codes; and detecting a level of a received signal Level (power) of the transmission power from the reception level detector 16 and the power transmitter 12 described above.
, A ROM 18 storing a predetermined control program, a RAM 19 used as an arithmetic processing area by a CPU 20, which will be described later, and various types of arithmetic processing.
And a CPU 20 for controlling the CPU 9.

The power transmitting section 12 has a function of converting power received from a power supply circuit (not shown) into a high-frequency current and transmitting the high-frequency current wirelessly from the transmitting antenna 11. In this example, the power transmitting unit 12 is controlled by the CPU 20 to transmit power from the transmitting antenna 11, thereby
Transmission means for transmitting power to a mobile information processing body such as a C card is configured. The data transmitting unit 13 includes, for example, a modulator that modulates data or the like into a signal suitable for wireless communication, and uses the transmitting antenna 1 as a wireless signal using data or the like to be transmitted input from the CPU 20 or the like.
1 has a function to transmit.

The data receiving section 15 is composed of, for example, a demodulator for demodulating a radio-received signal into data or the like. The data receiving section 15 demodulates a signal received from the receiving antenna 14 into data or the like and outputs the data to the CPU 20 or the like. It has the function to do.
Further, the data receiving section 15 has a function of outputting a signal received by the receiving antenna 14 to the reception level detecting section 16. In this example, the data receiving unit 15 is the CPU 2
By receiving a signal from the receiving antenna 14 under the control of 0, a receiving means for receiving a signal from a mobile information processing body such as an IC card is configured.

The reception level detecting section 16 is a data receiving section 1
5 has a function of detecting the level of the signal input from the IC card 2. In this example, the level of the power (response power) of the response signal received from the IC card 2 by the receiving antenna 14 is detected and detected. A function of notifying the CPU 20 of the received signal level thus determined. In this example, the reception level detection unit 16 is controlled by the CPU 20 to detect the level of the reception signal as described above, so that the detection means for detecting the level of the signal received from the mobile information processing body such as an IC card is provided. Be composed.

Here, generally, the power transmitted from the transmitting antenna 11 of the reader / writer 1 is
It decreases as the distance from becomes larger. Therefore, for example, when the same amount of power is transmitted from the transmission antenna 11 of the reader / writer 1, the antenna 1
As the distance between the antenna 1 and the antenna 2 of the IC card 2 increases, the operating power received by the IC card 2 decreases. From this, as the distance between the transmitting antenna 11 of the reader / writer 1 and the antenna 21 of the IC card 2 increases, the level of a response signal and the like transmitted from the IC card 2 to the reader / writer 1 decreases. The level of the reception signal detected by the reception level detection unit 16 of the reader / writer 1 described above decreases.

The transmission power control unit 17 controls the power transmission unit 12 so that the power received by the IC card 2 is constant according to the reception signal level detected by the reception level detection unit 16. Has a function of adjusting the power transmitted from the transmitting antenna 11 by the control unit.
In this example, the transmission power control unit 17 is controlled by the CPU 20 to adjust the transmission power as described above,
Transmission power adjustment means for adjusting the power transmitted from the transmission means so that the power received by a mobile information processing body such as an IC card is constant according to the reception signal level detected by the detection means. Be composed.

In the transmission power control unit 17, as an example of the transmission power adjustment processing, the power transmitted by the power transmission unit 12 in response to the reception signal level notified from the CPU 20 being larger than a predetermined value. Is controlled to increase the power transmitted by the power transmission unit 12 in response to the reception signal level notified from the CPU 20 being smaller than the predetermined value.

The above-mentioned predetermined value is a target value of the level of the response signal from the IC card 2, and in this example,
The transmission power from the power transmission unit 12 is adjusted so that the response signal level from the IC card 2 approaches the target value.
That is, as described above, when the operating power received by the IC card 2 is low, the response signal level from the IC card 2 is low, and when the operating power received by the IC card 2 is high, the IC card Since the response signal level from the IC card 2 is also high, the response signal level from the IC card 2 is fixed to a predetermined value as described above, so that the magnitude of the power received by the IC card 2 is increased. Can be made constant.

In order to make the response signal level from the IC card 2 constant, that is, to make the electric power received by the IC card 2 constant, the electric power received by the IC card 2 is not necessarily set to a substantially constant value. No need to keep
In short, the power supplied to the IC card 2 may have a width as long as the power value does not hinder the operation of the IC card 2. The CPU 20 expands the control program stored in the ROM 18 into the RAM 19 and executes the control program, thereby executing various arithmetic processes and the above-described processing of each processing unit 1
Control of processing by 1 to 19 is performed.

With the above configuration, the reader / writer 1 transmits the operating power to the IC card 2 in a non-contact manner, and performs signal communication with the IC card 2 in a non-contact manner. IC card 2 existing in
After transmitting the power to the IC card 2, the signal from the IC card 2 is received, and according to the level of the detected received signal, the transmission power is controlled so that the power received by the IC card 2 is constant. adjust. This allows the reader / writer to adjust the transmission power to an appropriate level according to, for example, the distance between the IC card and the reader / writer, so that stable operating power can be supplied to the IC card. it can.

Specifically, for example, even when the IC card is located relatively far from the reader / writer within the communicable area of the reader / writer, the IC card receives a sufficient supply of operating power. Therefore, it is possible to ensure that high-quality information communication is performed between the reader / writer and the IC card. Also, for example, even when the IC card is located at a relatively short distance from the reader / writer within the communicable area of the reader / writer, the IC card is excessively damaged to the extent that the internal IC circuit or the like is destroyed. Power supply to the IC card, it is possible to prevent the IC card from being destroyed, and it is also possible to keep the excessively supplied excess power from being wasted. it can.

Also, even if the distance between the IC card existing in the communicable area of the reader / writer and the reader / writer changes during communication or the like, the reader / writer cannot communicate with the IC card. By adjusting the transmission power in accordance with the distance, the quality of information communication and the like between the reader / writer and the IC card can be stabilized. Further, as shown in the above embodiment, in the present invention,
Since the reader / writer is provided with each function unit for performing the above-described transmission power adjustment processing, and by adjusting the power transmitted from the reader / writer, the power received by the IC card is stabilized, so that For example, there is an advantage that it is not necessary to particularly improve an IC card that requires a thin, lightweight, and low price.

Here, in the reader / writer shown in the above-mentioned embodiment, for example, a processor such as a CPU executes a control program on a hardware resource including a processor and a memory to execute the above-described transmission power adjustment processing. Although the control is performed, in the present invention, each functional unit for executing the processing may be configured as an independent hardware circuit.

Further, in the above embodiment, the adjustment of the transmission power performed by the reader / writer includes the adjustment of decreasing the transmission power according to the level of the signal received from the IC card being larger than a predetermined value, and the adjustment of the IC card. And adjustment to increase the transmission power in response to the level of the signal received from the device being smaller than a predetermined value.However, for example, the reader / writer is provided with only a function of performing one of the adjustments. You may. Specifically, by providing the reader / writer with the adjustment function of reducing the transmission power, which is the former, it is possible to prevent excessive power from being supplied to the IC card close to the reader / writer, In addition, by providing the latter function of adjusting the transmission power in the reader / writer, it is possible to ensure that sufficient operating power is supplied to an IC card distant from the reader / writer.

Further, the form of power transmission and signal communication between the reader / writer and the IC card is not necessarily limited to those described in the above embodiment, and the point is that power transmission and signal communication are performed in a non-contact manner. The power transmission and the signal communication may be performed in any form as long as it is possible. For example, in the above embodiment, the IC card is configured to transmit a signal using the carrier wave of the transmission power from the reader / writer, but the IC card does not use such a carrier wave, and the operating power received from the reader / writer is not used. A configuration in which a signal using an electromagnetic wave or the like is transmitted to the reader / writer using the above may be used.

Also, for example, the configuration and arrangement of the antenna provided in the reader / writer or the IC card do not necessarily use the coil wound in a rectangular shape or the manner of arrangement of the coil as shown in the above embodiment. In short, any antenna may be used in any arrangement as long as it can perform power transmission and signal communication in a non-contact manner.

Further, for example, in the reader / writer shown in the above embodiment, the power transmission and the signal transmission are performed using the transmitting antenna and the signal is received using the receiving antenna. A configuration including a transmitting antenna and a signal communication antenna, performing power transmission using the power transmitting antenna, and transmitting and receiving signals using the signal communication antenna may be used. Further, for example, a configuration may be used in which a reader / writer is provided with only one antenna, and the one antenna is shared to perform power transmission and signal transmission / reception. Similarly, the IC card does not necessarily have to use a configuration in which power reception and signal transmission / reception are performed by one antenna as in the above-described embodiment. For example, an antenna for power reception and an antenna for signal communication are not necessarily used. A configuration in which the antenna and the antenna are separately provided may be used.

The signal received by the reader / writer from the IC card to adjust the transmission power and used to detect the level may be any signal. In short, the signal received by the reader / writer from the IC card may be used. By detecting the level of the signal thus obtained, the power received by the IC card can be grasped to a practically effective level, so that the power received by the IC card can be kept constant. What is necessary is just to use the structure which can adjust transmission power.

Further, in the above-described embodiment, a case has been described in which an IC card which does not have an internal power supply and operates by electric power received from a reader / writer in a non-contact manner is used as the movement information processing body. As the information processing body, any mobile information processing body may be used as long as it performs power transmission and signal communication with the reader / writer in a non-contact manner. For example, even when a power source is provided inside the mobile information processing body, the power source is not used for signal transmission processing, and the level of a signal transmitted from the mobile information processing body is changed to the level of the mobile information processing body. In a configuration that varies depending on the reception power of the body, the reader / writer can effectively perform the adjustment processing of the transmission power according to the level of the signal received from the mobile information processing body.

[0037]

As described above, according to the reader / writer of the present invention, the operating power is transmitted to the mobile information processing body such as an IC card in a non-contact manner, and the mobile information processing body is contactlessly contacted with the mobile information processing body. In performing the signal communication, the level of the signal received from the mobile information processing body is detected, and the power received by the mobile information processing body is fixed according to the detected level of the received signal. In order to adjust the transmission power to the mobile information processing body, for example, regardless of the size of the distance to the mobile information processing body existing in the communicable area or the fluctuation of the distance, Can be supplied.

[Brief description of the drawings]

FIG. 1 is an example of an IC card system including a reader / writer according to the present invention.

FIG. 2 is a configuration example of a reader / writer according to an embodiment of the present invention.

FIG. 3 is an example of an IC card system.

FIG. 4 is a diagram for explaining fluctuations in power received by the IC card from the reader / writer.

[Explanation of symbols]

1. Reader / writer, 2. IC card, 11.
Transmission antenna, 12 power transmission unit, 13 data transmission unit, 14 reception antenna, 15 data reception unit, 16 reception level detection unit, 17 transmission power control unit, 18 · ROM, 19 · · RAM, 2
0 ... CPU, 21 ... antenna,

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Manabu Nakamura 3-14-20 Higashinakano, Nakano-ku, Tokyo Inside Kokusai Denki Co., Ltd. (72) Inventor Mitsuhiro Okada 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Electric Inside the corporation

Claims (1)

[Claims] 1. A reader / writer that transmits operating power to a mobile information processing body in a non-contact manner and performs non-contact signal communication with the mobile information processing body, and transmits power to the mobile information processing body. Transmitting means, receiving means for receiving a signal from the mobile information processing means, detecting means for detecting the level of the received signal, and receiving by the mobile information processing means according to the detected received signal level A transmission power adjusting means for adjusting the power transmitted from the transmitting means so that the power is kept constant.