JP2003332820A - Booster antenna for ic card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sufficient information transmission range even when IC cards are overlapped when using. <P>SOLUTION: A booster coil L<SB>2</SB>operating as an external antenna of an IC chip CP is formed on a card base material CD, and the booster coil L<SB>2</SB>is repeatedly and continuously bent so as to have effective widths W<SB>1</SB>and W<SB>2</SB>equal to or more than three times as large as the coil width W<SB>a</SB>. Even though the booster coil L<SB>2</SB>is overlapped on another IC card, mutual interference with an antenna coil of the other IC card can be minimized. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-contact type IC.
The present invention relates to a booster antenna for an IC card that can be preferably used for a card.

[0002]

2. Description of the Related Art A non-contact type IC card has an I
An antenna coil is incorporated together with the C chip.
However, the IC card mentioned here includes a so-called IC tag.

The IC chip is integrally mounted on the card base together with the antenna coil adapted to the frequency used. The antenna coil is formed in a rectangular frame shape along the outer periphery of the card base material of the IC card in order to obtain sufficient transmission / reception sensitivity. Therefore, the antenna coil can receive the radio wave from the external reader / writer and supply the operating power to the IC chip to realize the necessary data communication between the IC chip and the reader / writer. The communication method and frequency of the IC chip are appropriately selected according to the intended use and the required information transmission distance.

[0004]

According to the prior art, when a plurality of IC cards are stacked and used, the antenna coils of the respective IC cards interfere with each other to lower the transmission / reception sensitivity and the information transmission distance. There was a problem that it might run short.

Therefore, in view of the problems of the prior art, the object of the present invention is to use the IC cards in a stacked manner by repeatedly and continuously bending the booster coil in the long side direction of the card base material. An object of the present invention is to provide a booster antenna for an IC card that can obtain an information transmission distance.

[0006]

The structure of the present invention for achieving the above object is formed by forming a booster coil which operates as an external antenna of an IC chip on a card substrate, and the booster coil has a coil width of The gist of the invention is to repeatedly bend the card base material in the long side direction so that the effective width is three times or more.

The booster coil can be repeatedly bent in the short side direction of the card base material so that the effective width is three times or more the coil width.

An exciting coil electromagnetically coupled to the antenna of the IC chip may be connected in series to the booster coil, and the booster coil may have an opening area larger than that of the exciting coil.

Further, the exciting coil and the booster coil are
It can be formed in a two-dimensional spiral shape, and the winding directions can be the same.

A resonance capacitor may be attached to the booster coil.

However, in the present invention, the coil width of the booster coil means the total width including the gap of the parallel conductor pattern arranged in parallel for the number of turns of the booster coil through the gap, and the effective width is as follows. The maximum width of the bent portion of the parallel conductor pattern.

[0012]

According to the structure of the present invention, the booster coil, which operates as an external antenna of the IC chip, can receive the radio wave from the external reader / writer and transmit it to the IC chip, and the response data from the IC chip can be transmitted. It can be transmitted to an external reader / writer. Since the booster coil is continuously bent to have an effective width that is three times or more the coil width, even if another IC card having a rectangular antenna coil is stacked, the antenna along the long side of the card base material is stacked. Since it crosses the straight long side of the coil completely diagonally,
Mutual interference with the antenna coil of another IC card is extremely small, and there is almost no reduction in transmission / reception sensitivity or reduction in information transmission distance. However, the booster coil shall be formed on the card base material so as to realize the maximum opening area within the effective area of the card base material.

By repeatedly bending the booster coil in the short side direction of the card base material repeatedly, mutual interference with the antenna coil of another IC card can be more effectively suppressed.

The exciting coil connected in series with the booster coil acts as a secondary coil for the antenna of the IC chip and can perform a signal amplifying action according to the turn number ratio of both.

By providing the booster coil with an opening area larger than that of the exciting coil, a sufficiently high transmission / reception sensitivity can be easily realized. The exciting coil preferably has a minimum opening area required to install the IC chip therein in order to electromagnetically couple the exciting coil to the antenna of the IC chip sufficiently densely.

The exciting coil and the booster coil, which are formed in a two-dimensional spiral shape, can be arranged on the card substrate so as not to overlap each other, and can be formed with a predetermined number of turns to realize a required inductance.

The exciting coil and the booster coil can be easily formed by using one conductive pattern or wire by making the winding directions the same.

The booster coil is provided with a capacitor for resonance so that the Q at resonance can be increased and a sharp frequency characteristic can be realized.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

A booster antenna for an IC card comprises an exciting coil L1 and a booster coil L2 connected in series with the exciting coil L1 on a card substrate CD (FIGS. 1 and 2).

The card substrate CD is formed into a thin card shape with an insulating material such as a paper material or a synthetic resin material. The exciting coil L1 and the booster coil L2 are two-dimensional spiral parallel conductor patterns having the same winding direction on the card substrate CD by a conductive pattern formed by a method such as printing or etching, or by one wire. Has been formed. The exciting coil L1 is a booster coil L
An IC chip CP having the antenna A mounted on the chip main body IC is installed inside the exciting coil L1 and is formed outside the device.

The booster coil L2 has an opening area larger than that of the exciting coil L1 and has a larger number of turns than the exciting coil L1. The booster coil L2 is repeatedly and continuously bent to form bent portions G1 and G1 along each long side of the card substrate CD so as to have a bending angle θ≈90 °, and one short side of the card substrate CD. Also in the lateral direction,
It is repeatedly and continuously bent so that the bending angle θ is approximately 90 °, and another bending portion G2 is formed. The effective width W1 of the booster coil L2 at each bent portion G1 and G2
, W2 is W2> W1 ≧ 3 Wa with respect to the coil width Wa.
Has become. A capacitor C for resonance is formed in the booster coil L2 and is attached to the booster coil L2. The capacitor C can secure a required capacitance by forming parallel conductor patterns of a predetermined length and a predetermined interval through the comb-shaped conductive patterns facing each other.

The exciting coil L1 is electromagnetically coupled to the antenna A of the IC chip CP, and the booster coil L2 is
Together with the capacitor C, it is connected in series to the exciting coil L1 via the jumper wire B1. However, the symbol M in FIG.
Indicates electromagnetic coupling between the antenna A and the exciting coil L1. The exciting coil L1 has a small opening area corresponding to the outer size of the IC chip CP and is electromagnetically coupled to the antenna A sufficiently densely.

The booster coil L2 receives the radio wave S1 from an external reader / writer (not shown), and the exciting coil L1
, The chip body I of the IC chip CP via the antenna A
It is possible to supply high-frequency power to C, activate the chip body IC, and transmit the data contained in the radio wave S1 to the chip body IC. At this time, the antenna A is excited by the exciting coil L1. In addition, IC chip CP
Responds to the data contained in the radio wave S1 from the reader / writer as necessary, and load-modulates the radio wave S1 according to the response data. The contents of the load modulation are transmitted from the antenna A to the booster coil L2 via the exciting coil L1 and to the reader / writer via the booster coil L2. That is, the booster coil L2 operates as an external antenna of the IC chip CP via the exciting coil L1 and the antenna A, and can increase the information transmission distance of the IC chip CP.

The IC card having the booster coil L2 is a card base CD of another IC card in addition to the card base CD.
Even if a is used repeatedly, there is almost no decrease in the information transmission distance with the reader / writer RW (FIG. 3). A rectangular frame-shaped antenna coil La is formed along the outer periphery of another card base CDa, and the antenna coil La is, for example, a card base CDa via a resonance capacitor Ca.
It is connected to the upper IC chip CPa. Therefore, when the card bases CD and CDa are stacked, the booster coil L2
The bent portions G1, G1, and G2 diagonally completely cross each straight side of the antenna coil La (FIG. 4), so that mutual interference with the antenna coil La can be minimized.

[0026]

[Other Embodiments] When embossing portions CD1 and CD1 for displaying the card number, name, expiration date, etc. are provided on the card base material CD (FIG. 5), the booster coil L2 avoids the embossing portions CD1 and CD1. Shall be formed. Further, in the booster coil L2, the bent portion G2 in the short side direction of the card substrate CD may be omitted (the same figure). Further, the capacitor C includes a plurality of capacitors C1, C2 ...
May be connected in parallel to achieve the required capacity (see the figure).

The exciting coil L1 may be provided inside the booster coil L2 (FIG. 6), and the resonance capacitor C is used.
May be formed outside the booster coil L2 (the same figure). Further, the booster coil L2 may be repeatedly and continuously bent in the short side direction of the card substrate CD a plurality of times to form a bent portion G2 (the same figure). In addition, in FIG.
The effective width W2 of the bent portion G2 is set to W2 .apprxeq.W1 .gtoreq.3 Wa.

In the above description, the booster coil L2
Is the bending angle θ≈90 ° at each of the bent portions G1 and G2.
Instead of being bent to θ, it may be bent to θ <90 ° (FIG. 7 (A)) or θ> 90 ° (FIG. 7 (B)). Further, the bending angle θ may be changed discontinuously ((C) in the figure) or may be continuously changed ((D) in the figure). However, in FIG. 7, the booster coil L2
, The antenna coil La is shown ignoring the respective coil widths.

Excitation coil L1 and booster coil L
2 may be formed on the card substrate CD by a single insulating wire. Further, the booster coil L2, together with the resonance capacitor C, may be directly connected to the IC chip CP having no antenna A (FIG. 8) and operated as an external antenna of the IC chip CP. However, the IC chip CP at this time may have a built-in capacitor for coupling, may be connected in series to the external capacitor C (FIG. (A)), or may be connected in parallel ( The same figure (B)).

[0030]

As described above, according to the present invention, the booster coil formed on the card base material is repeatedly and continuously bent so that the booster coil and the antenna coil of another IC card interact with each other. Since the interference can be suppressed to a minimum, there is an excellent effect that a sufficient information transmission distance can be easily obtained even when the IC cards are stacked and used.

[Brief description of drawings]

FIG. 1 is a schematic plan view of the overall configuration

FIG. 2 Equivalent circuit diagram

[Figure 3] Usage status explanatory diagram

[Fig. 4] Schematic illustration of usage

FIG. 5 is a view corresponding to FIG. 1 showing another embodiment (1).

FIG. 6 is a view corresponding to FIG. 1 showing another embodiment (2).

FIG. 7 is a schematic explanatory view showing another embodiment.

FIG. 8 is an equivalent circuit explanatory diagram showing another embodiment.

[Explanation of symbols]

CP ... IC chip A ... antenna CD ... Card base material Wa ... Coil width W1, W2 ... Effective width L1 ... Excitation coil L2 ... Booster coil C ... Capacitor

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01Q 1/52 G06K 19/00 K

Claims (7)

[Claims] 1. A booster coil that operates as an external antenna of an IC chip is formed on a card base material, and the booster coil has a long side of the card base material having an effective width three times or more the coil width. Booster antenna for IC cards, characterized by being repeatedly bent in the same direction. 2. The booster antenna for an IC card according to claim 1, wherein the booster coil is repeatedly bent in the short side direction of the card base material so as to have an effective width of three times or more the coil width. . 3. The booster antenna for an IC card according to claim 1, wherein an exciting coil electromagnetically coupled to the antenna of the IC chip is connected in series to the booster coil. 4. The booster antenna for an IC card according to claim 3, wherein the booster coil has an opening area larger than that of the exciting coil. 5. The exciting coil and the booster coil are 2
The booster antenna for an IC card according to claim 3 or 4, wherein the booster antenna is formed in a three-dimensional spiral shape. 6. The exciter coil and the booster coil have the same winding direction.
Booster antenna for C card. 7. The booster antenna for an IC card according to claim 1, wherein a resonance capacitor is attached to the booster coil.