JP2003233780A - Data communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To resolve a problem in attachment of a reader-writer 2 wherein modulation factors A of a non-contact IC card 1 are different in attaching the reader-writer 2 to a wooden wall 3 and in attaching the reader-writer 2 to a ferrite wall 4, and a transmission success rate of data is deteriorated unless electrical characteristics of the reader-writer 2 and the non-contact IC card 1 are adjusted each time in accordance with an attaching member of the reader- writer 2. <P>SOLUTION: When attaching the reader-writer 32 to an external object such as a wall, an iron plate shielding a magnetic field generated by the reader-writer 32 is inserted between the reader-writer 41 and the external object. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mounts a reader / writer on a wall or a desk for entrance / exit or a ticket gate so that a non-contact IC card and a reader / writer perform data transmission / reception while maintaining a non-contact state. Data communication device.

[0002]

2. Description of the Related Art FIG. 20 shows a conventional data communication device shown on pages 104 and 154 of "Wireless Card Guidebook 99" (edited by the Council for Promotion of Practical Use of Wireless Cards, published March 1999). FIG. 21 is a perspective view showing the electric characteristics of a conventional data communication device. In the figure, 1 is a non-contact IC card having a data transmission / reception function, 2 is a power supply to the non-contact IC card 1 while maintaining a non-contact state, and data is transmitted / received to / from the non-contact IC card 1. Reader / writer, 3 is a wooden wall to which the reader / writer 2 is attached, 1
Reference numeral 1 is a coil of the reader / writer 2, 12 is a magnetic line of force created by the coil 11, and 13 is a magnetic field received by the non-contact IC card 1.

FIG. 22 is a block diagram showing the data receiving section of the non-contact IC card 1. In the figure, 21 is a card coil for receiving the transmission signal of the reader / writer 2, 22 is a rectifying circuit, and 23 is a rectifying circuit 22. Output voltage, 24 is a regulator, 25 is an output voltage 23 of the rectifying circuit 22, and a reference potential V
_{When c1} or more, a comparator that compares the output voltage 23 with the reference potential V _c2 , and 26 is a demodulation circuit that demodulates the received signal according to the comparison result of the comparator 25.

Next, the operation will be described. First, when the reader / writer 2 transmits an H level signal (hereinafter, referred to as an H signal) out of digital binary signals, a current having an amplitude value I ₁ is passed through the coil 11. As a result, FIG.
Since magnetic field lines 12 as shown in 1 are created around the coil 11, the non-contact IC card 1 receives the magnetic field 13 having the amplitude value H ₁ (see FIG. 23A).

On the other hand, when the reader / writer 2 transmits an L level signal (hereinafter referred to as an L signal) of the digital binary signal, a current having an amplitude value I ₂ is passed through the coil 11. However, I ₁ > I ₂ . As a result, FIG.
Since the magnetic force lines 12 as shown in FIG. 1 are formed around the coil 11, the non-contact IC card 1 receives the magnetic field 13 having the amplitude value H ₂ (see FIG. 23A). However, H
₁ > H ₂ .

Therefore, the signal waveform received by the card coil 21 of the non-contact IC card 1 is as shown in FIG. 23 (a), and the output voltage 23 of the rectifying circuit 22 becomes V ₁ during H signal transmission. On the other hand, when transmitting the L signal,
The output voltage 23 of the rectifier circuit 22 becomes V ₂ (see FIG. 23).
(See (b)). However, V ₁ > V ₂ .

Here, the reader / writer 2 sends the data to ASK.
In the case of (Amplitude Shift Keying) modulation and transmission, the non-contact IC card 1 receives a signal with the modulation degree A, but the target value (for example, 10%) is set to the modulation degree A, When the modulation degree A deviates from the lower limit value (for example, 8%) or the upper limit value (for example, 12%), it becomes impossible to determine H / L in the comparator 25 of the non-contact IC card 1. A = (H ₁ −H ₂ ) / (H ₁ + H ₂ ) × 100% = (V ₁ −V ₂ ) / (V ₁ + V ₂ ) × 100% Therefore, for example, when V ₁ = 3V, A ≦ Since the reference potential V _c1 that satisfies 12% is 2.36 V and the reference potential V _c2 that satisfies A ≧ 8% is 2.55 V, the output voltage V ₂ during L signal transmission is 2.36 V ≦ V ₂ ≦ 2.5
The electrical characteristics of the reader / writer 2 and the non-contact IC card 1 need to be adjusted in advance so that the voltage becomes 5V.

Comparator 25 of non-contact IC card 1
Is the output voltage 23 of the rectifier circuit 22 is the reference potential V_c1that's all
At that time, the output voltage 23 and the reference potential V_c2Compare
It Then, the demodulation circuit 26 of the non-contact IC card 1 is
The received signal is demodulated according to the comparison result of the comparator 25.
It That is, the output voltage 23 of the rectifier circuit 22 is V₁That
For example, V₁> V_c2Therefore, the H signal is demodulated and the rectification circuit
22 output voltage 23 is V _TwoIf so, V_Two<V_c2Tona
Therefore, the L signal is demodulated.

In the above-mentioned conventional example, the reader / writer 2 is attached to the wooden wall 3, but the reader / writer 2 adjusted for the wooden wall 3 has a large relative magnetic permeability (for example, a wall made of ferrite). 4) (see FIG. 24 and FIG. 25), as shown in FIG. 26, even if the reader / writer 2 passes currents of amplitude values I ₁ and I ₂ through the coil 11,
The amplitude value of the magnetic field 13 received by the non-contact IC card 1 is H ₁ ,
Instead of H ₂ , it becomes H ₁ ^′ , H ₂ ^′ . Therefore, the output voltage 23 of the rectifier circuit 22 of the non-contact IC card 1 does not become V ₁ and V ₂ , but becomes V ₁ ^′ and V ₂ ^′ . As a result, as shown in FIG. 26B, when the output voltage V ₂ of the rectifier circuit 22 becomes larger than the reference potential V _c2 , it is impossible to determine H / L in the comparator 25 of the non-contact IC card 1. become.

[0010]

Since the conventional data communication apparatus is constructed as described above, the reader / writer 2 is attached to the wooden wall 3 and the reader / writer 2 is attached to the ferrite wall 4. And, the modulation degree A of the non-contact IC card 1 is different. Therefore, if the electrical characteristics of the reader / writer 2 and the non-contact IC card 1 are adjusted each time according to the mounting member of the reader / writer 2,
There was a problem that the success rate of data transmission deteriorates.

The present invention has been made to solve the above problems, and it is an object of the present invention to obtain a data communication device capable of maintaining the success rate of data transmission even if the attachment member of the reader / writer changes. To aim.

[0012]

In a data communication apparatus according to the present invention, when a reader / writer is attached to an external object, a shield member for shielding a magnetic field generated by the reader / writer is inserted between the reader / writer and the external object. It is the one.

In the data communication device according to the present invention, a conductor is used to form the shielding member.

In the data communication device according to the present invention, the shielding member is constructed by using an iron plate.

The data communication device according to the present invention uses a shield member having a three-dimensional shape.

The data communication device according to the present invention uses a box-shaped shielding member having no lid.

The data communication device according to the present invention uses a shielding member having a mesh structure.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a configuration diagram showing a data communication device according to a first embodiment of the present invention, and FIG. 2 is an explanatory diagram showing electrical characteristics of the data communication device according to the first embodiment of the present invention. In the figure, 31 is a non-contact IC card having a data transmission / reception function, 32 is a power supply to the non-contact IC card 31 while maintaining a non-contact state, and data is transmitted / received to / from the non-contact IC card 31. The reader / writer 33 is a fixing material for fixing the reader / writer 32 so that the reader / writer 32 and the iron plate 35 are separated by a predetermined distance, and is composed of, for example, a foam material having a small loss with respect to a magnetic field.

Reference numeral 34 is a wooden wall (external object) to which the reader / writer 32 is attached, and 35 is the reader / writer 32 and the wall 3.
4 is an iron plate (shielding member) that is inserted between the four and shields the magnetic field generated by the reader / writer 32. Here, the iron plate 35
Although the shielding member is configured by using, the shielding member may be a conductor, and a metal plate other than iron or the like may be used. Reference numeral 41 is a coil of the reader / writer 32, 42 is a magnetic line of force created by the coil 41, and 43 is a magnetic field received by the non-contact IC card 31.

FIG. 3 is a block diagram showing the data receiving portion of the non-contact IC card 31, in which 51 is a card coil for receiving the transmission signal of the reader / writer 32, 52 is a rectifying circuit, and 53 is a rectifying circuit 52. The output voltage, 54 is a regulator, 55 is the output voltage 53 of the rectifier circuit 52 is the reference potential V
A comparator for comparing the output voltage 53 with the reference potential V _c2 when the voltage is greater than or equal to _c1 and a demodulation circuit for demodulating a received signal according to the comparison result of the comparator 55. Figure 5
2 is a flowchart showing the processing contents of the data communication device according to the first embodiment of the present invention.

Next, the operation will be described. First, when the reader / writer 32 transmits an H level signal (hereinafter referred to as an H signal) of the digital binary signals, the amplitude value I ₁
Current is applied to the coil 41 (step ST
1). As a result, magnetic force lines 42 as shown in FIG. 2 are created around the coil 41, so that as shown in FIG. 4A, the non-contact IC card 31 receives the magnetic field 43 with the amplitude value H ₁ ( Step ST2). However, magnetic field line 4
The linear shape of 2 has the same shape regardless of the presence or absence of the fixing material 33 because the fixing material 33 does not affect the magnetic force lines 42.
The magnetic force lines 42 are parallel to the iron plate 35 on the surface of the iron plate 35.

On the other hand, when the reader / writer 32 transmits an L level signal (hereinafter referred to as an L signal) of the digital binary signal, a current having an amplitude value I ₂ is passed through the coil 41 (step ST3). ). However, I ₁ > I ₂ . As a result, magnetic force lines 42 as shown in FIG. 2 are created around the coil 41, so that as shown in FIG.
The non-contact IC card 31 receives the magnetic field having the amplitude value H ₂ (step ST4). However, H ₁ > H ₂ . Also in this case, the linear shape of the magnetic force lines 42 has the same shape regardless of the presence or absence of the fixing member 33, because the fixing member 33 does not affect the magnetic force lines 42. In addition, the magnetic force line 42 is the iron plate 35.
It is parallel to the iron plate 35 on the surface of.

Therefore, the signal waveform received by the card coil 51 of the non-contact IC card 31 is as shown in FIG. 4A, and the output voltage 53 of the rectifier circuit 52 becomes V ₁ when the H signal is transmitted. On the other hand, when transmitting the L signal,
The output voltage 53 of the rectifier circuit 52 becomes V ₂ (FIG. 4B).
See). However, V ₁ > V ₂ .

Here, the reader / writer 32 sends the data to the AS.
K (Amplitude Shift Keying)
When modulated and transmitted, the non-contact IC card 31 receives a signal with the modulation degree A (step ST
5) A target value (for example, 10%) is set for the modulation degree A, and when the modulation degree A deviates from the lower limit value (for example, 8%) or the upper limit value (for example, 12%), the non-contact IC It becomes impossible to determine H / L in the comparator 55 of the card 31. A = (H ₁ −H ₂ ) / (H ₁ + H ₂ ) × 100% = (V ₁ −V ₂ ) / (V ₁ + V ₂ ) × 100% Therefore, for example, when V ₁ = 3V, A ≦ Since the reference potential V _c1 satisfying 12% is 2.36 V and the reference potential V _c2 satisfying A ≧ 8% is 2.55 V, the output voltage V ₂ during L signal transmission is 2.36 V ≦ V ₂ ≦ 2.5
The electrical characteristics of the reader / writer 32 and the non-contact IC card 31 need to be adjusted in advance so as to be 5 V (steps ST6 to ST8).

Comparator 55 of non-contact IC card 31
The output voltage 53 of the rectifier circuit 52 when the above reference potential _{V c1,} and compares the output voltage 53 and a reference potential _{V c2} (step ST9). Then, the demodulation circuit 56 of the non-contact IC card 31 demodulates the received signal according to the comparison result of the comparator 55. That is, the output voltage 5 of the rectifier circuit 52
If 3 is V ₁ , then V ₁ > V _c2 , so the H signal is demodulated, and if the output voltage 53 of the rectifier circuit 52 is V ₂ , then V
_{Since 2} <V _c2 , the L signal is demodulated (step ST
10).

In this embodiment, the reader / writer 32 is attached to the wooden wall 34, but the reader / writer 32 adjusted for the wooden wall 34 is a wall having a large relative magnetic permeability (for example, made of ferrite). Even when attached to the wall 36) (see FIGS. 6 and 7), the amplitude value of the magnetic field 31 received by the non-contact IC card 31 does not change. That is, the linear shape of the magnetic field lines 42 formed around the coil 41 is such that the wall on which the reader / writer 32 is mounted is made of wood, or
Even if it is made of ferrite, the iron plate
Since it is parallel to, it always takes the same shape. Therefore,
The reader / writer 32 applies currents of amplitude values I ₁ and I ₂ to the coil 4
If it is set to 1, the amplitude value of the magnetic field 31 received by the non-contact IC card 31 will always be H ₁ and H _2.
The output voltage 53 of the rectifier circuit 52 is also V ₁ and V ₂ . Therefore, even if the reader / writer 32 adjusted for the wooden wall 34 is attached to the ferrite wall 36, the non-contact I
The comparator 55 of the C card 31 can discriminate H / L.

As is clear from the above, the first embodiment
According to this, when the reader / writer 32 is attached to an external object such as a wall, the iron plate 35 that shields the magnetic field generated by the reader / writer 32 is configured to be inserted between the reader / writer 32 and the external object. Even if the material of the external object to which is attached changes, the data transmission success rate can be maintained.

Embodiment 2. Although the reader / writer 32 is attached to the flat plate-shaped wall in the first embodiment, as shown in FIG. 8 or FIG.
Alternatively, when attaching the reader / writer 32 to a corner portion of the ferrite wall 36, as shown in FIG. 9 or 11, a three-dimensional iron plate 35 (for example, a box-shaped iron plate 35 without a lid) is used. Reader / writer 32 and walls 34, 36
It should be inserted between. As a result, even if the mounting location of the reader / writer 32 changes, the linearity of the magnetic force lines 42 does not change.
Even when it is attached to the corner portions of 4, 36, there is an effect that the data transmission success rate can be maintained.

Embodiment 3. In the first embodiment, the iron plate 35 having no holes is shown, but as shown in FIGS. 12 to 15, the iron plate 35 having a mesh structure is used.
Alternatively, a may be used, and the same effect as that of the first embodiment can be obtained. That is, the mesh-shaped iron plate 3
Even when 5a is used, the magnetic field lines 42 are parallel to the iron plate 35a on the surface of the iron plate 35a, so that the first embodiment described above is adopted.
The same effect as can be obtained.

Fourth Embodiment In the second embodiment described above, the iron plate 35 having no holes is used. However, as shown in FIGS. 16 to 19, the iron plate 35 having a mesh structure is used.
Alternatively, a may be used, and the same effect as that of the second embodiment can be obtained. That is, the mesh-shaped iron plate 3
Even when 5a is used, the magnetic field lines 42 are parallel to the iron plate 35a on the surface of the iron plate 35a, so that the second embodiment described above is used.
The same effect as can be obtained.

[0031]

As described above, according to the present invention, when the reader / writer is attached to the external object, the shielding member for shielding the magnetic field generated by the reader / writer is inserted between the reader / writer and the external object. Therefore, even if the material of the external object to which the reader / writer is attached changes, the data transmission success rate can be maintained.

According to the present invention, since the shield member is constituted by using the conductor, there is an effect that the magnetic field generated by the reader / writer can be shielded without inviting a complicated structure.

According to the present invention, since the shielding member is constituted by using the iron plate, there is an effect that the cost increase of the product can be suppressed.

According to the present invention, since the shielding member having a three-dimensional shape is used, the same linear magnetic force line can be obtained even if the mounting position of the reader / writer changes.

According to the present invention, since the box-shaped shielding member having no lid is used, the data transmission success rate can be maintained even when the reader / writer is attached to a corner of a wall, for example. There is an effect that can be done.

According to this invention, since the shielding member having the mesh structure is used, there is an effect that the cost increase of the product can be suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a data communication device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing electrical characteristics of the data communication device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a data receiving unit of a non-contact IC card.

FIG. 4 is a waveform diagram showing a signal waveform or the like received by a card coil of a non-contact IC card.

FIG. 5 is a flowchart showing the processing contents of the data communication device according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram showing a data communication device according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram showing electrical characteristics of the data communication device according to the first embodiment of the present invention.

FIG. 8 is a configuration diagram showing a data communication device according to a second embodiment of the present invention.

FIG. 9 is an explanatory diagram showing electrical characteristics of the data communication device according to the second embodiment of the present invention.

FIG. 10 is a configuration diagram showing a data communication device according to a second embodiment of the present invention.

FIG. 11 is an explanatory diagram showing electrical characteristics of the data communication device according to the second embodiment of the present invention.

FIG. 12 is a configuration diagram showing a data communication device according to a third embodiment of the present invention.

FIG. 13 is an explanatory diagram showing electrical characteristics of the data communication device according to the third embodiment of the present invention.

FIG. 14 is a configuration diagram showing a data communication device according to a third embodiment of the present invention.

FIG. 15 is an explanatory diagram showing electrical characteristics of the data communication device according to the third embodiment of the present invention.

FIG. 16 is a configuration diagram showing a data communication device according to a fourth embodiment of the present invention.

FIG. 17 is an explanatory diagram showing electrical characteristics of the data communication device according to the fourth embodiment of the present invention.

FIG. 18 is a configuration diagram showing a data communication device according to a fourth embodiment of the present invention.

FIG. 19 is an explanatory diagram showing electrical characteristics of the data communication device according to the fourth embodiment of the present invention.

FIG. 20 is a block diagram showing a conventional data communication device.

FIG. 21 is an explanatory diagram showing electrical characteristics of a conventional data communication device.

FIG. 22 is a configuration diagram showing a data receiving unit of a non-contact IC card.

FIG. 23 is a waveform diagram showing a signal waveform or the like received by the card coil of the non-contact IC card.

FIG. 24 is a block diagram showing a conventional data communication device.

FIG. 25 is an explanatory diagram showing electrical characteristics of a conventional data communication device.

FIG. 26 is a waveform diagram showing a signal waveform or the like received by the card coil of the non-contact IC card.

[Explanation of symbols]

31 non-contact IC card, 32 reader / writer, 33
Fixing material, 34 Wooden wall (external object), 35 Iron plate (shielding member), 35a Mesh structure iron plate (shielding member), 36
Ferrite wall (external object), 41 coil, 42
Magnetic field lines, 43 magnetic fields, 51 card coils, 52 rectifier circuit, 53 output voltage of rectifier circuit, 54 regulator, 55 comparator, 56 demodulator circuit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoji Isoda             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F term (reference) 5B058 CA17 KA24 KA29 YA20                 5K012 AA04 AB03 AC06 AC08 AC10                       AE13 BA02

Claims (6)

[Claims] 1. A non-contact IC having a data transmitting / receiving function.
In a data communication device including a card and a reader / writer that supplies power to the non-contact IC card while maintaining a non-contact state, and a reader / writer that transmits / receives data to / from the non-contact IC card, the reader / writer is provided. A data communication device, wherein a shield member for shielding a magnetic field generated by the reader / writer is inserted between the reader / writer and the external object when being attached to an external object. 2. The data communication device according to claim 1, wherein the shield member is formed by using a conductor. 3. The data communication device according to claim 2, wherein the shielding member is made of an iron plate. 4. The data communication device according to claim 1, wherein a shield member having a three-dimensional shape is used. 5. The data communication device according to claim 4, wherein a box-shaped shielding member having no lid is used. 6. The data communication device according to claim 1, wherein a shielding member having a mesh structure is used.