JP2008146567A - Reader/writer equipment of non-contact communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide R/W equipment of a non-contact communication system capable of housing a circuit and an antenna coil within a small area and expanding a transmittable and receivable range to a more practical distance. <P>SOLUTION: The reader/writer equipment of the non-contact communication system for transmitting and receiving information to/from a storage medium without contacting comprises: a circuit for performing processing for transmitting and receiving the information; an antenna coil disposed at a close position around the circuit for making it possible to transmit and receive the information between the recording medium and the circuit and supplying required power to the recording medium; and ground loop wiring in a closed loop shape extended from a part of ground wiring inside the circuit and circulated once, twice or more so as to surround an area where an electronic component to be easily affected by a magnetic field among the electronic components disposed inside the circuit is disposed at least. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-contact communication system that transmits and receives information between a recording medium such as an IC tag and a reader / writer device (hereinafter referred to as an R / W device) by non-contact short-range wireless communication. The present invention relates to a reader / writer device suitable for downsizing a contactless communication system.

A non-contact communication system that transmits and receives information between a recording medium such as an IC tag and a reader / writer device (hereinafter referred to as an R / W device) by non-contact short-range wireless communication is known. It is used for various purposes such as access control of people and people (see, for example, Patent Documents 1, 2, and 3).
In the process of downsizing the system in such a non-contact communication system, since the influence of the magnetic field generated from the antenna becomes a problem, for example, in the system described in Patent Document 1, the magnetic field of the magnetic field can be reduced using a known short ring. We are trying to reduce the impact as much as possible.
JP 2003-187195 A JP-A-2005-102185 JP 2002-312738 A

In the technique described in Patent Document 1, a short ring is provided between an antenna arranged along the periphery of an IC card that is a recording medium and a circuit (cell) arranged almost at the center of the card. Although the technique described in Patent Document 1 relates to an IC card, this technique can also be applied to an R / W device. By using this technique, the influence of a magnetic field can be reduced to some extent.
However, in order to further reduce the size of the system, specifically, the circuit, which is the main part of the R / W device, is accommodated in an area of about several mm to several tens of mm square, and the antenna coil is placed in the vicinity of this circuit If it is going to provide, there exists a possibility that the influence of a magnetic field cannot fully be reduced with a short ring. In the current non-contact communication, the transmission / reception distance between the recording medium and the R / W device is small (several millimeters), and it is difficult to expand to a more practical range (several tens of millimeters). .

  The present invention has been made in order to solve the above-described problems. The circuit can be accommodated in an area of several mm to several tens of mm square with the antenna coil disposed in a close position, and the size of the circuit can be reduced. Another object of the present invention is to provide an R / W device for a non-contact communication system capable of transmitting and receiving at a practical distance.

In order to achieve the above object, the inventors of the present invention conducted extensive research, and as a result, surrounded by the wiring pattern extended from the ground wiring, the entire circuit or a region susceptible to the magnetic field in the circuit, and The inventors have conceived that the adverse effect of the magnetic field on the circuit can be effectively reduced by making the wiring pattern a closed loop.
Specifically, as described in claim 1, the present invention provides a reader / writer device of a non-contact communication system that performs non-contact transmission / reception of information to / from a storage medium. And an antenna coil that is arranged in a proximity position around the circuit, enables transmission / reception of information between the recording medium and the circuit, and supplies necessary power to the recording medium A closed loop that extends from a part of the ground wiring in the circuit and surrounds at least one region of the electronic components arranged in the circuit that is susceptible to the influence of a magnetic field. And a ground loop wiring.
In the description of the present invention, “transmission / reception” includes both transmission and reception as well as transmission and reception only.

As described in claim 2, the ground loop wiring may be extended from the ground wiring of an electronic component most susceptible to a magnetic field among electronic components arranged on the circuit. For example, when the electronic component is an IC or a transistor, the electronic component may be provided directly on the ground terminal or on the ground wiring connected to the ground terminal.
According to a third aspect of the present invention, a part of the ground wiring in the circuit may constitute a part of the ground loop wiring.
In this way, it is not necessary to form a new wiring for the ground loop wiring, and space can be saved by using the existing wiring.

Some circuit boards have circuits formed on both sides. In such a circuit board, as described in claim 4, a part of the ground loop wiring extending from one surface side may pass through the other surface side.
According to this configuration, for example, even when there is no space for forming the ground loop wiring on one surface side, there is an advantage that the ground loop wiring can be formed using the space on the other surface side or the existing ground wiring.
When a plurality of circuit boards are stacked, as described in claim 5, a part of the ground loop wiring extending from one circuit board passes through at least one other circuit board. You may comprise.
According to this configuration, for example, even when there is no space for forming the ground loop wiring on one circuit board, the ground loop wiring can be formed using the space of another circuit board or the existing ground wiring. There are advantages.
In the circuit to which the present invention is applied, as an electronic component that is easily influenced by a magnetic field, an IC or a transistor can be cited as described in claim 6.

  The R / W device of the present invention can fit the circuit and the antenna coil in a small area, specifically, the circuit in a range of several mm to several tens of mm square with the antenna coil in close proximity. In addition, transmission and reception can be performed at a practical distance even if the size is reduced.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram of a main part of an R / W device according to a first embodiment for explaining the basic concept of the present invention.
Reference numeral 1 denotes a circuit board, on which a circuit 11 and an antenna coil 13 of about several mm to several tens of mm square are arranged.
The circuit 11 executes processing for reading information and writing information, and various electronic components 12b in addition to the IC 12a are arranged on a wiring pattern (not shown). In the figure, the alternate long and short dash line indicates the outer edge of the region of the circuit 11 composed of the wiring pattern and the electronic component 12b.
The antenna coil 13 transmits and receives information between a tag (not shown) that is a recording medium and the circuit 11, and also has a role of supplying necessary power to the tag.
The basic configuration of the circuit 11 and the antenna coil 13 is the same as that of a known one, so that further explanation is omitted here.

A power wiring and a ground wiring (not shown) are connected to the wiring pattern of the circuit 11. One of the plurality of terminals of the IC 12a that is one of the electronic components is connected to the ground wiring pattern of the wiring patterns.
In this embodiment, the ground wiring pattern is extended from the ground terminal (ground terminal) to the outer edge of the circuit 11 among the plurality of terminals of the IC 12a which is the electronic component most susceptible to the magnetic field. Then, the ground wiring pattern is joined along the outer peripheral edge of the circuit 11 at a coupling point 14a on the ground wiring pattern that extends around the gap between the antenna coil 13 and the circuit 11 and extends from the ground terminal of the IC 12a. . As a result, a closed-loop ground loop wiring 14 that goes around the circuit 11 is formed.

Next, another embodiment of the present invention will be described with reference to FIGS.
FIG. 2A is a schematic diagram of a main part of the R / W device according to the second embodiment of the present invention.
The circuit board 2 of FIG. 2A has circuits formed on both front and back surfaces (a circuit on the front surface side is denoted by reference numeral 21a and a circuit on the back surface side is denoted by reference numeral 21b). In such a circuit board 2, the antenna coil 23 may be provided on both the front and back surfaces.
Further, a plurality of through holes 2a, 2b,... Are formed in the circuit board 2, and the wiring patterns of the circuits 21a, 21b on both the front and back surfaces are connected through the through holes 2a, 2b,. Has been.

Also in this embodiment, as in the first embodiment, the ground loop wiring 24 is extended from the ground terminal of the IC 22a, and the loop is made to reach the coupling point 24a on the ground wiring pattern extending from here to the outside of the circuit 21a. ing.
In this embodiment, the first difference from the first embodiment is that a part of the ground loop wiring 24 extended from the circuit 21a on the front surface extends to the circuit 21b on the back surface through the through hole 2a ( In FIG. 2 (a), the ground loop wiring 24 on the back surface side is indicated by a dotted line), which is a point that returns to the circuit 21a on the front surface through another through hole 2b.
Thus, in the present invention, the ground loop wiring 24 may be formed through the two circuits 21 a and 21 b formed on the front and back of the circuit board 2.

In this embodiment, the second difference from the first embodiment is that the ground loop wiring 24 is formed so as to surround a part of the circuits 21a and 21b, not the entire circuits 21a and 21b. Is a point.
An electronic component indicated by reference numeral 22c in FIG. 2A is a secondary battery or the like that is hardly affected by a magnetic field. Such an electronic component 22 c may be positioned outside the ground loop wiring 24.
As described above, in the present invention, a partial region of the circuits 21a and 21b, that is, a region susceptible to the influence of the magnetic field may be specified, and the ground loop wiring 24 may be formed so as to surround the specific region.

In this embodiment, a part of the ground loop wiring 24 passes through the circuits 21a and 21b. In this case, an extra space for newly forming the ground loop wiring 24 may not be secured in the circuits 21a and 21b. Therefore, in such a case, a part of the ground loop wiring 24 may be configured using an existing ground wiring pattern formed in the circuit 11.
In the case where the existing ground wiring pattern formed in the circuit 11 is used as a part of the ground loop wiring 24 as in this embodiment, as shown in FIG. When a part of the loop 11 is looped in the circuit 11 (the looped part is indicated by a solid line 26b), if the ground wiring pattern (26a, 26b) is used as it is, the ground loop wiring 24 is doubled ( (Or multiple) loops. In such a case, the entrance portion of the loop 26b is bridged (the bridge portion is indicated by a dotted line 26c) so that the ground loop wiring 24 extends straight by the ground wiring pattern 26a, and a part of the midway portion of the loop 26b is formed. It is good to cut | disconnect (a cutting location is shown with the code | symbol 26d).

FIG. 3 is a perspective view schematically showing the main part of the R / W device according to the third embodiment of the present invention.
In this embodiment, a multilayer circuit board is configured by laminating a plurality (two in the illustrated example) of circuit boards 3 and 4.
It is assumed that circuits are formed on the front and back surfaces of the lower circuit board 3 (the front side circuit is indicated by reference numeral 21a and the back side circuit is indicated by reference numeral 21b). Although not particularly illustrated, the antenna coil 33 may be provided on each of the circuit boards 3 and 4.
In the example shown in FIG. 3, it is assumed that the IC 32 a is arranged on the circuit 31 b on the back surface side of the lower circuit board 3.

As in the second embodiment, the lower circuit board 3 has a plurality of through holes 3a and 3b, and the upper circuit board 4 has a plurality of through holes 4a and 4b.
In this embodiment, the ground loop wiring 34 is extended from the ground terminal of the circuit IC 32 a disposed on the circuit 31 b on the back surface of the lower circuit board 3. The ground loop wiring 34 reaches the through hole 3a through a gap between the circuit 31b and the antenna coil 33, and extends to the upper circuit board 4 through the through hole 3a. Then, the through-hole 4a of the upper circuit board 4 reaches another through-hole 4b using the ground wiring pattern in the circuit 41, and passes through this through-hole 4b to the circuit 31a on the surface of the lower circuit board 3 Extend. Further, it reaches the through hole 3b through the existing ground wiring pattern of the circuit 31a, returns from the through hole 3b to the circuit 31b on the back surface, and reaches the coupling point 34a.

Thus, in the present invention, the ground loop wiring 34 may be formed not only through the two circuits 31 a and 31 b formed on the front and back of the circuit board 3 but also through another circuit board 4.
In addition, when a part or all of a plurality of circuit boards have circuits on both front and back sides, or when the number of circuit boards to be stacked is three or more, the second embodiment or the third embodiment described above is used. The embodiments may be applied individually, or the second embodiment and the third embodiment may be applied in combination.

The inventor of the present invention created a test piece and conducted a communication test in order to test the effect of the present invention.
The test piece used is a circuit in which a circuit including an IC is formed in a 15 mm square region, and an antenna coil is provided around the circuit. The gap between the antenna coil and the outer peripheral edge of the circuit was about 1.5 mm. In this gap, a ground loop wiring extending from the ground terminal of the IC and making a round around the circuit was formed with a line width of 0.2 mm.
As a result, the influence of the magnetic field can be greatly reduced as compared with the case where no ground loop wiring is provided, the output can be increased to about 100 mW, and the transmission / reception distance that has conventionally been about 3 to 5 mm can be reduced to 40 to 40 mm. It was possible to enlarge to about 50 mm.

Although a preferred embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment.
For example, the ground loop wirings 14, 24, and 34 have been described as being formed in only one line, but if the effect is increased by forming two or three or more lines, two or three or more lines may be formed.
The ground loop wires 14, 24, and 34 are not limited to the ICs 12a, 22a, and 33a, and may be extended from other electronic components 12b, 22b, and 33b, or on the circuits 11, 21a, 21b, 31a, and 31b. You may make it extend from the intermediate part of the formed grounding wiring pattern.

  The present invention can be widely applied to R / W devices of non-contact communication systems used for physical distribution and human management.

1 is a schematic diagram of a main part of an R / W device according to a first embodiment for explaining a basic concept of the present invention. (A) is a schematic view of the main part of the R / W device according to the second embodiment of the present invention, and (b) is an example of forming a ground loop wiring when the ground wiring in the circuit is in a loop shape. FIG. The outline of the principal part of R / W apparatus concerning 3rd embodiment of this invention is shown with the perspective view.

Explanation of symbols

1, 2, 3, 4 Circuit boards 2a, 2b, 3a, 3b, 4a, 4b Through holes 11, 21a, 21b, 31a, 31b Circuits 12a, 22a, 32a ICs (electronic components susceptible to magnetic fields)
12b, 22b, 32b, 42b Other electronic components 13, 23, 33 Antenna coils 14, 24, 34 Ground loop wirings 14a, 24a, 34a

Claims (6)

In a reader / writer device of a non-contact communication system that performs non-contact transmission / reception of information with a storage medium,
A circuit that performs processing for transmission and reception of the information;
An antenna coil that is disposed in a proximity position around the circuit, enables transmission and reception of information between the recording medium and the circuit, and supplies necessary power to the recording medium;
A closed loop that extends from a part of the ground wiring in the circuit and surrounds at least one region of the electronic components arranged in the circuit that is susceptible to the influence of a magnetic field. Ground loop wiring,
A reader / writer apparatus for a non-contact communication system. 2. The contactless communication system according to claim 1, wherein the ground loop wiring extends from a ground wiring of an electronic component that is most susceptible to a magnetic field among electronic components arranged on the circuit. Reader / writer device. 3. A reader / writer device for a contactless communication system according to claim 1, wherein a part of the ground wiring in the circuit constitutes a part of the ground loop wiring. The circuit board in which circuits are formed on both front and back surfaces, a part of the ground loop wiring extending from one surface side passes through the other surface side. Reader / writer device for contact communication system. 5. When laminating a plurality of circuit boards, a part of the ground loop wiring extending from one circuit board passes through at least one other circuit board. A reader / writer device for a non-contact communication system according to any one of the above. The reader / writer device for a non-contact communication system according to claim 1, wherein the electronic component is a transistor or an IC.

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