JPH05135222A - Non-contact transfer method of data for semiconductor memory medium - Google Patents

Abstract

PURPOSE:To efficiently attain the transmission of information bidirectionally through a coil while a physical non-contact state between an IC card and a reader/writer is held. CONSTITUTION:A first spiral coil 110 is formed on a VW plane, and a second coil 120 whose receiving sensitivity is high is formed beside it, at a reader/writer device 100 side. On the other hand, a third spiral coil 210 is formed on an XY plane in parallel to the VW plane, at an IC card 200 side. Information transmitted from the reader/writer device 100 is transmitted, again, on a carrier from the first coil 110, and received by the third coil 210. The information transmitted from the IC card reader 200 is transmitted to the reader/writer device 100 side as the form of load fluctuation of the coil 210, and detected by the second coil 120.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless data transfer method for a semiconductor storage medium, and more particularly to a data transfer method suitable for contactless data transfer to an IC card.

[0002]

2. Description of the Related Art In recent years, IC has been used as a new information storage medium.
Cards are attracting attention. Although the IC card is a card-shaped storage medium that is convenient in its form, it has a semiconductor memory element built-in, and can record extremely large amount of information as compared with a magnetic card or the like. Further, in the IC card with a built-in CPU, since the IC card itself has an arithmetic processing function, it is highly useful in applications requiring a high degree of security.

A reader / writer device is used to write data in and read data from a semiconductor storage medium such as the IC card described above. By electrically contacting the input / output terminal on the reader / writer device side with the input / output terminal on the IC card side, power and clock can be supplied from the reader / writer device to the IC card.
In addition, it becomes possible to transfer data between them. As a new method of transferring data between the two, a method of transferring data while the two are physically kept in a non-contact state has recently been proposed. That is, the coil provided on the reader / writer device side and the coil provided on the IC card side magnetically couple the two so that power and clock are supplied and data is transferred. If such non-contact type data transfer is performed, an external input / output terminal becomes unnecessary and the IC card becomes more portable.

[0004]

However, the above-described conventional non-contact transfer method of data in the semiconductor storage medium has a problem that bidirectional information transfer via the coil cannot be efficiently performed. Generally, data transfer in a non-contact state is very disadvantageous in that accurate information transfer is performed, as compared with data transfer in a state where electrical contact is secured. That is, in order to perform data transfer in a non-contact state, a data signal is modulated by a carrier wave, and this modulated wave is transmitted from one coil to the other coil by electromagnetic induction, and then demodulation for the modulated wave is performed. It is necessary to perform a process of extracting the data signal of Moreover, in order to carry out bidirectional information transmission, in the conventional method, two coils, a transmitting coil and a receiving coil, are arranged in both the reader / writer device and the semiconductor storage medium. However, in a semiconductor storage medium such as an IC card, it is necessary to take advantage of the feature that it is a compact device that is convenient to carry, and it is difficult to arrange two sets of coils that enable efficient magnetic coupling.

Therefore, an object of the present invention is to provide a non-contact transfer method of data in a semiconductor storage medium which can efficiently perform bidirectional information transfer via a coil.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor storage medium and data writing / writing on the semiconductor storage medium.
A method for transferring data between a reader / writer device for reading and a reader / writer device, comprising: a first coil for transmission to the reader / writer device; and a second coil for reception having higher reception sensitivity than the first coil. And a third coil for reception provided on the semiconductor storage medium, and a first signal wave corresponding to data transmitted from the reader / writer device to the semiconductor storage medium,
A second signal wave corresponding to the data transmitted from the semiconductor storage medium to the reader / writer device is generated, and the reader / writer device side superimposes the first signal wave and the carrier wave to generate a modulated wave. The modulated wave is applied to the first coil for transmission, the second coil detects the load fluctuation occurring in the third coil, and the second signal wave is received. Of the modulated wave is received by the coil of No. 1 and the first signal wave is detected by demodulating the received modulated wave, and the load fluctuation is given to the third coil based on the second signal wave to physically It is designed to enable two-way data transfer while in a non-contact state.

[0007]

[Operation] In the data transfer method according to the present invention, the reader / writer device side requires two coils, a transmission coil and a reception coil, but the semiconductor storage medium side has a single dual-purpose function for both transmission and reception. Only the coil need be provided. The first signal wave generated by the reader / writer device is sent on the carrier wave from the transmission coil, and is received by the dual-purpose coil on the semiconductor storage medium side. On the other hand, the second signal wave generated in the semiconductor storage medium is transmitted to the reader / writer device side in the form of load fluctuation occurring in the dual-purpose coil and detected by the highly sensitive receiving coil. Thus, bidirectional data transfer can be efficiently performed by the three coils.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. FIG. 1 is a block diagram showing a reader / writer device 100 and an IC card 200 to which a contactless data transfer method according to the present invention is applied. The reader / writer device 100 includes a first coil 110 for transmission and a second coil 110 for reception.
Of the coil 120, and the IC card 200 is provided with the third coil 210 for both transmission and reception. As the second coil 120 for reception, one having higher reception sensitivity than that of the first coil 110 for transmission is used. When the reader / writer device 100 and the IC card 200 are placed in the data transfer state, the first coil 110 and the third coil 2
10 is electromagnetically coupled to the second coil 12 as well.
The 0 and the third coil 210 are electromagnetically coupled. Data transfer between the two is performed via these electromagnetic coupling paths. More specifically, the reader / writer device 1
00 supplies power and a clock to the IC card 200, and transmits and receives a data signal between them.

The reader / writer device 100 superimposes a first signal wave containing information on data to be transferred and a carrier wave of a predetermined frequency to generate a modulated wave, and the modulated wave is transmitted to the first coil 110. Give and send. On the other hand, the IC card 200 receives the transmitted modulated wave by the third coil 210, generates power source power by rectifying the received modulated wave, and extracts a predetermined frequency component from the received modulated wave. A signal wave is detected by generating a clock signal and demodulating the received modulated wave.

FIG. 2 shows an example of the above-mentioned carrier wave, signal wave and modulated wave. As the carrier wave shown in FIG. 2A, an example of a triangular wave is shown for convenience, but a sine wave or a rectangular wave carrier may of course be used. The data to be transmitted is shown in FIG.
It is prepared as a binary signal wave as shown in (b). Figure 2 (c)
2A is a waveform obtained by modulating the signal wave shown in FIG. 2B with the carrier wave shown in FIG. 2A, and is obtained by superimposing the carrier wave and the signal wave. First coil 11
A modulated wave as shown in FIG. 2C is given to 0, and this modulated wave is received by the third coil 210 on the IC card 200 side.

The principle of transmitting power, clock, and data from the reader / writer device 100 to the IC card 200 has been described above, but conversely, only data is transmitted from the IC card 200 to the reader / writer device 100. To be done. However, the carrier wave propagates only from the first coil 110 to the third coil 210, and there is no carrier wave propagation in the opposite direction. Therefore, in order to transfer data from the IC card 200 to the reader / writer device 100, the IC
On the card 200 side, a method of changing the input impedance of the third coil 210 is adopted. For example, when the resistance value of the resistance element connected to the third coil 210 is switched, the current flows through the first coil 110 and the second coil 120 electromagnetically coupled to the third coil 210. The load applied to the current will change. Therefore, the load fluctuation of the third coil 210 generated on the IC card 200 side can be detected by the first coil 110 or the second coil 120 on the reader / writer device 100 side. .. However, since the second coil 120 has a higher reception sensitivity, the load variation is detected by the second coil 120. In this way, if the IC card 200 causes the load fluctuation in the third coil 210 based on the second signal wave including the information regarding the data to be transferred, the second coil 120 on the reader / writer device 100 side. Will detect the second signal wave.

As described above, the load fluctuation of the third coil 210 can also be detected by the first coil 110. Therefore, in principle, bidirectional data transfer is possible without using the second coil 120. However, since the modulated wave as shown in FIG. 2 (c) is applied to the first coil 110, the load fluctuation component is placed on this modulated wave. In general, this load fluctuation component (second signal wave) is weaker than the first signal wave shown in FIG. 2 (b), so efficient detection cannot be expected. A feature of the present invention is that the second coil 120 is provided as a receiving-only coil for detecting the load fluctuation component. The second coil 120 does not need to transmit the modulated wave and has a higher receiving sensitivity than the first coil 110, so that the load fluctuation can be detected efficiently.

Next, FIG. 3 shows an embodiment showing the specific shapes and arrangements of the three coils used in the present invention. This figure shows a reader / writer device 100 and an IC card 200,
It shows the positional relationship of the three coils when placed in a state of performing data transfer. Now, a plane XY parallel to the card surface inside the IC card 200 and a plane VW parallel to the plane XY inside the reader / writer device 100 are defined as shown in the figure. In this embodiment, the first coil 110 on the reader / writer device side is a spiral coil formed on the VW plane, and the third coil 210 on the IC card side is a spiral coil formed on the XY plane. It consists of a coil. Each of them is formed so as to draw a spiral with the Z axis perpendicular to each plane as the central axis. These spiral coils can be easily constructed by a conductive layer formed by printing on a printed circuit board. On the other hand, the second coil 120 on the reader / writer device side has a conductor wire wound around a coil center axis 121 included in the VW plane, and a ferrite rod is inserted at the position of the coil center axis 121. It is in a state.

By arranging the coils having such a shape in the above arrangement, extremely efficient data transfer becomes possible. First coil 110 and third coil 210
And are spiral-shaped and face each other in parallel. Therefore, the modulated wave generated in the first coil 110 is efficiently transmitted to the third coil 210. Also,
Since it has a planar spiral shape, it is most suitable for being incorporated in the IC card 200 which is required to be a thin card. Ideally, the second coil 120 is arranged at a position most suitable for detecting the load fluctuation generated in the third coil 210. As a result of the experiment, the inventor of the present application has made the coil center axis 121 face the direction toward the center of the first coil 110, and has one end a of the second coil 120 near the outer periphery of the first coil 110. It has been found that it is optimal to place it in. It is preferable to arrange the end portion a on the VW plane in the sense that the end portion a approaches the first coil 110, but the end portion b may deviate from the VW plane.

Although the present invention has been described above based on the illustrated embodiment, the present invention is not limited to this embodiment and can be implemented in various modes other than this. For example, the shape and arrangement of each coil shown in FIG. 3 are shown as an example, and the present invention is not limited to this.
Further, as the second coil 120, a magnetic detecting element having a function equivalent to that of the second coil 120, for example, a Hall element may be used.

[0016]

As described above, according to the non-contact data transfer method of the present invention, a transmission coil and a reception coil are provided on the reader / writer device side, and a transmission / reception coil is provided on the semiconductor storage medium side. Since each of them is provided, bidirectional information transmission via the coil can be efficiently performed.

[Brief description of drawings]

FIG. 1 is a reader / writer device 100 and an IC card 20 to which a contactless data transfer method according to the present invention is applied.
It is a block diagram which shows 0.

FIG. 2 is a waveform diagram showing an example of a carrier wave, a signal wave, and a modulated wave used in the data contactless transfer method according to the present invention.

FIG. 3 is a diagram showing an arrangement example of three coils used in the non-contact data transfer method according to the present invention.

[Explanation of symbols]

 100 ... Reader / Writer Device 110 ... First Coil 120 ... Second Coil 121 ... Coil Center Axis 200 ... IC Card 210 ... Third Coil

Claims (2)

[Claims] 1. A method for transferring data between a semiconductor storage medium and a reader / writer device for writing / reading data to / from the semiconductor storage medium, comprising: a first transmission device for transmitting data to the reader / writer device. Coil and this first
A second coil for reception having higher reception sensitivity than that of the first coil, a third coil for reception provided on the semiconductor storage medium, and a first coil corresponding to data transmitted from the reader / writer device to the semiconductor storage medium. A signal wave and a second signal wave corresponding to the data transmitted from the semiconductor storage medium to the reader / writer device are generated, and the reader / writer device side superimposes the first signal wave and the carrier wave on the modulated wave. Is generated, the modulated wave is applied to the first coil for transmission, and the load fluctuation occurring in the third coil is detected by the second coil to detect the second coil.
Signal wave is received, and on the semiconductor storage medium side, the modulated wave is received by the third coil, and the received modulated wave is demodulated to detect the first signal wave. The semiconductor memory is characterized in that load variation is applied to the third coil on the basis of the signal wave, and bidirectional data transfer can be performed while both are in a physically non-contact state. A contactless transfer method of data on a medium. 2. The non-contact data transfer method according to claim 1, wherein the first coil is formed by a spiral coil formed on the first plane, and the first coil is parallel to the first plane. A semiconductor memory characterized in that a third coil is formed by a spiral coil formed on a plane 2 and a second coil is formed by a coil whose one end is arranged on an outer peripheral portion of the first coil. A contactless transfer method of data on a medium.