JP4810033B2 - Antenna coil and contactless card using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna coil for transmitting information in a non-contact state in personal authentication, merchandise management, physical distribution, and the like, and a non-contact card using the antenna coil.
[0002]
[Prior art]
As shown in FIG. 5, a general non-contact card is mainly an electronic device such as an IC chip mounting portion 7 on which a plastic film substrate 20 and an antenna coil 2 and an IC 3 formed on one surface of the plastic film substrate 20 are mounted. It is comprised from the circuit pattern and the cover film (not shown) which covers and protects this electronic circuit pattern.
[0003]
An electronic circuit pattern used for such a non-contact type card, for example, a non-contact IC card, is generally formed by printing using copper or aluminum etching or silver paste. In order to make a closed circuit in this and to constitute an antenna coil, the start point and end point of the electronic circuit pattern wound several times on the concentric circle are connected to each other. That is, the jumper unit 6 is provided to connect the start point and the end point of the pattern wound a plurality of times. This jumper portion is made of silver paste for ease of connection and the like, and connects the start point and the end point in a state of being insulated from a line in the middle of a pattern wound a plurality of times.
[0004]
[Problems to be solved by the invention]
However, in the non-contact IC card described above, the jumper portion 6 is made of silver paste for ease of connection and the like, but the silver paste has a relatively high resistivity. In other words, the volume resistivity of the silver paste is ^{1.6 × 10 -5 [Ω · m} ] about, copper volume resistivity 1.67 × 10 ^- 10 times higher than ^{6 [Ω} · m]. For this reason, energy loss is increased, which causes a reduction in communication efficiency.
[0005]
The present invention has been made in view of the above-described points, and provides an antenna coil in which the resistivity of a jumper portion is reduced, power loss is reduced, and communication efficiency is improved, and a non-contact card using the antenna coil. For the purpose.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, the antenna coil according to the first invention is wound a plurality of times in the same plane, and both ends thereof are connected by jumper portions to form a closed circuit pattern, and the induction electromagnetic field is used as a transmission medium. In an antenna coil for transmitting information in a contact state, the jumper portion is composed of a conductive paste and an electrical good conductor (hereinafter referred to as “good conductor”), and the good conductor is in the middle of the conductive paste. It is characterized by being provided in close contact with or along at least part of the conductive paste .
[0007]
With the above configuration, the resistivity of the entire jumper portion can be lowered by interposing a good conductor in the middle of the conductive paste of the jumper portion. Thereby, power loss can be reduced and communication efficiency can be improved. In addition, the resistivity is low at the portion where the good conductor conducts electricity instead of the conductive paste. Thereby, like the serial wiring of a conductor having a relatively high resistivity and a good conductor having a low resistivity, the resistivity of the entire jumper portion is lowered, power loss is reduced, and communication efficiency is improved. Furthermore, since electricity flows through the portion where the conductive paste having a relatively high resistivity and the good conductor having a low resistivity are along, the same effect as the parallel wiring is obtained, and the resistivity of the portion is lowered. In accordance with this, the resistivity of the entire jumper unit is also reduced, power loss is reduced, and communication efficiency is improved.
[0008]
An antenna coil according to a second invention is characterized in that, in the antenna coil according to the first invention, the good conductor has a lower volume resistivity than the conductive paste.
[0009]
With the above configuration, the good conductor has a volume resistivity lower than that of the conductive paste, so that the resistivity of the entire jumper portion is lowered, power loss is reduced, and communication efficiency is improved.
[0010]
An antenna coil according to a third invention is characterized in that, in the antenna coil according to the first invention, the jumper portion is composed of the conductive paste and the good conductor to reduce the resistivity of the entire jumper portion. And
[0011]
With the above configuration, since the resistivity of the entire jumper unit is lowered , power loss is reduced and communication efficiency is improved.
[0012]
A non-contact card according to a fourth aspect of the present invention comprises a card substrate and an antenna coil that is wound a plurality of times within the surface of the card substrate and has both ends thereof connected by jumper portions, and is guided by the antenna coil. In a non-contact card that transmits information in a non-contact state using an electromagnetic field as a transmission medium, the antenna coil according to any one of the first to third inventions is used as the antenna coil.
[0013]
With the above configuration, the resistance of the jumper as a whole is reduced as in the case of series wiring or parallel wiring of a conductor having a relatively high resistivity and a good conductor having a low resistivity. Communication efficiency can be improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an antenna coil and a contactless card according to an embodiment of the present invention will be described with reference to the accompanying drawings. Here, a non-contact IC card will be described as an example of the non-contact type card.
[0015]
The non-contact IC card is mainly composed of a plastic film substrate, an electronic circuit pattern such as an antenna coil and an IC chip mounting portion formed on one surface of the plastic film substrate, and the conventional non-contact IC card. And a cover film that covers and protects the electronic circuit pattern.
[0016]
FIG. 1 shows an electronic circuit pattern 1. This electronic circuit pattern 1 is mainly composed of an antenna coil 2 and an IC chip 3.
[0017]
The antenna coil 2 includes a winding part 5, a jumper part 6, and an IC chip mounting part 7. The winding portion 5 is a portion that performs transmission and reception in an induction electromagnetic field, and is wound eight times in a square spiral shape along one side of a plastic film substrate that is a card substrate. The jumper portion 6 is a member for connecting the both ends of the winding portion 5 to form a closed circuit pattern. A specific structure of the jumper unit 6 will be described later. The IC chip mounting part 7 is a part for incorporating the IC chip 3 into the antenna coil 2.
[0018]
As shown in FIG. 2, the jumper portion 6 includes a conductive paste 10 and a hot terminal 11 interposed in the middle of the conductive paste 10, and both end portions of the winding portion 5 are adjacent to it. Each is connected to the hot terminal 11 using the conductive paste 10. Adjacent hot terminals 11 are also connected using the conductive paste 10.
[0019]
The conductive paste 10 is made of, for example, silver paste, and an insulating resist film (not shown) is provided between the winding part 5 and the jumper part 6, and between the winding part 5 and the conductive paste 10. Insulated.
[0020]
The hot terminal 11 is a member for reducing the resistivity of the jumper unit 6 as a whole, and is composed of a good conductor. As this good conductor, for example, a metal such as copper, gold, silver, or aluminum, that is, a metal having a volume resistivity lower than that of the conductive paste can be used. The hot terminal 11 is provided between two adjacent winding portions 5. Since the winding portion 5 is wound eight times, eight hot terminals 11 are provided between the winding portions 5. A gap is provided between the hot terminal 11 and the winding portion 5 and is insulated from each other. The conductive paste 10 is connected to the edge of the hot terminal 11, and the edge of each adjacent hot terminal 11 is connected by the conductive paste 10. As a result, a series wiring structure of a conductive paste having a relatively high resistivity and a good conductor having a low resistivity is obtained, and the resistivity of the entire jumper portion 6 is reduced.
[0021]
The IC chip mounting portion 7 is a portion where the IC chip 3 is installed, and is provided on the innermost side of the winding portion 5.
[0022]
The IC chip 3 stores information according to applications such as personal authentication, product management, and logistics. The IC chip 3 is connected to the winding part 5 of the antenna coil 2. Accordingly, the IC chip 3 exchanges information with the external processing device in a non-contact state using the induction electromagnetic field as a transmission medium via the antenna coil 2.
[0023]
Next, an antenna coil according to another embodiment of the present invention will be described.
[0024]
In the antenna coil 2, the jumper portion 6 is provided with the hot terminal 11 interposed in the middle of the conductive paste, but a good conductor may be provided in close contact along at least a part of the conductive paste. Specifically, as shown in FIG. 3, both ends of the winding part 5 are connected in a state where the upper surface of the hot terminal 11 is covered with the conductive paste 10, or the conductive terminal 10 is electrically conductive as shown in FIG. For example, the jumper portion 6 may be formed by bringing the good conductor 12 into close contact with the surface of the paste 10. For example, a silver paste or the like can be used as the conductive paste, and a metal such as copper, gold, silver, or aluminum can be used as the good conductor.
[0025]
By adopting such a structure, in the portion where the good conductor is in close contact with the conductive paste, electricity flows through both the good conductor and the conductive paste. Becomes lower. Accordingly, the resistivity of the entire jumper unit is also reduced and the power loss is reduced, so that the communication efficiency can be improved.
[0026]
[Example 1]
Next, a specific example of the electronic circuit pattern 1 having the above configuration will be shown.
[0027]
A non-contact IC card was constructed with the following dimensions. A 50 μm thick polyethylene terephthalate film (trade name “PET A-4300” manufactured by Toyobo Co., Ltd.) and a 20 μm thick polyester adhesive (trade name “Byron 300” manufactured by Toyobo Co., Ltd.) A copper foil having a thickness of 35 μm was pasted. Next, the winding part 5, the IC chip mounting part 7, and the hot terminal 11 were formed by wet etching using a ferric chloride solution. The short side L1 of the winding part 5 is 50 mm, the long side L2 is 80 mm, the width L3 of the eight winding parts 5 is 17.5 mm, the width L5 of the single winding part 5 is 0.5 mm, for hot use The width L6 of the terminal 11 was 1.0 mm, and the width L8 of the gap between the winding portion 5 and the hot terminal 11 was 0.25 mm.
[0028]
Next, a portion corresponding to the jumper portion 6 on the winding portion 5 is covered with an acrylic resin insulating resist having a thickness of 20 μm (product surface “ML25089” manufactured by Nippon Atchison Co., Ltd.), and silver is used as a conductive paste from above. With the paste (product name “DW250L-1” manufactured by Toyobo Co., Ltd.), the end of the winding part 5 is connected to the adjacent hot terminal and the adjacent hot terminal to form the jumper part 6. The antenna coil 2 was obtained. The width L7 where the conductive paste 10 overlaps the hot terminal 11 was 0.2 mm, and the width L4 of the jumper portion 6 was 2.0 mm.
[0029]
By forming the jumper part 6 with the hot terminal made of copper foil interposed in the middle of the conductive paste as described above, the volume resistivity of the jumper part 6 becomes 6.07 [Ω · m]. It was.
[0030]
Next, the IC chip 3 (trade name “I-CODE” manufactured by Philips Co., Ltd.) was mounted on the IC chip mounting portion 7 to produce a non-contact IC card. And, as a result of measuring the communicable distance (distance between the non-contact IC card and the measurement antenna) using a measurement machine connected to the measurement antenna to a reader (manufactured by marantz, trade name “ICW900F”), The communication possible distance of this non-contact IC card was 20 cm.
[0031]
[Example 2]
In the same manner as in Example 1, the winding portion 5, the IC chip mounting portion 7 and the hot terminal 11 were formed on a polyethylene terephthalate film, and the portion corresponding to the jumper portion 6 on the winding portion 5 was covered with an insulating resist. . Next, the both ends of the winding part 5 are connected with a 20 μm thick silver paste (trade name “DW250L-1”) with a thickness of 20 μm so as to be in close contact with the upper surface of the hot terminal 11, and a jumper. An antenna coil was formed. Next, as in Example 1, an IC chip was mounted to produce a non-contact IC card. And when the communicable distance was measured like Example 1, the communicable distance of this non-contact IC card was 20 cm.
[0032]
[Comparative example]
A winding portion and an IC chip mounting portion were formed in the same manner as in Example 1 except that the hot terminal was not formed, and a portion corresponding to the jumper portion on the winding portion was covered with an insulating resist. Next, both ends of the winding portion were connected with a 20 μm thick silver paste to form a jumper portion. The volume resistivity of the jumper part formed only from this silver paste was 9.33 [Ω · m], 1.54 times that of the jumper part of Example 1.
[0033]
Next, in the same manner as in Example 1, an IC chip was mounted to obtain a non-contact IC card. And when the communicable distance was measured like Example 1, the communicable distance of this non-contact IC card was 17 cm.
[0034]
[effect]
(1) Since the good conductor with low resistivity is interposed in the jumper portion 6 as described above, the resistivity of the entire jumper portion 6 can be reduced. As a result, power loss in the antenna coil 2 can be reduced and communication efficiency can be improved.
[0035]
(2) Furthermore, the communication distance can be extended as the communication efficiency improves. In the above experimental example and comparative example, the communication distance of the conventional non-contact type card is 17 cm, whereas in the non-contact type card of the present invention, the communication distance is 20 cm at the tip locking portion, and the communication distance is increased by 3 cm. I was able to.
[0036]
[Modification]
(1) In the above embodiment, a non-contact IC card has been described as an example. However, the present invention is not limited to this non-contact IC card and can be applied to all cards that need to transmit information in a non-contact state. .
[0037]
Furthermore, the present invention can be applied not only to a card but also to any device that needs to transmit information in a non-contact state between two separated objects.
[0038]
(2) In the said embodiment, although the hot terminal 11 was provided in all between each winding part 5, you may provide it at intervals of every other or every 2 or more. Also in this case, the same operations and effects as the above embodiment can be achieved.
[0039]
【The invention's effect】
As described above, the antenna coil and the non-contact card according to the present invention can provide the following effects.
[0040]
Since a good conductor with low resistivity is interposed in the jumper portion, the resistivity of the entire jumper portion can be lowered. As a result, power loss in the antenna coil can be reduced and communication efficiency can be improved.
[0041]
Furthermore, the communication distance can be extended as the communication efficiency improves.
[Brief description of the drawings]
FIG. 1 is a plan view showing an electronic circuit pattern according to an embodiment of the present invention.
FIG. 2 is a plan view showing a conductive paste and a hot terminal according to an embodiment of the present invention.
FIG. 3 is a plan view showing a conductive paste and a hot terminal according to another embodiment of the present invention.
FIG. 4 is a plan view showing a conductive paste and a good conductor according to another embodiment of the present invention.
FIG. 5 is a plan view showing a conventional electronic circuit pattern.
[Explanation of symbols]
1: Electronic circuit pattern, 2: Antenna coil, 3: IC chip, 5: Winding part, 6: Jumper part, 7: IC chip mounting part, 10: Conductive paste, 11: Hot terminal, 12: Good conductor, 20: Plastic film substrate.

Claims (4)

In an antenna coil that is wound a plurality of times in the same plane and connects both ends thereof with jumpers to form a closed circuit pattern, and transmits information in a non-contact state using an induction electromagnetic field as a transmission medium,
The jumper part is composed of a conductive paste and a good electrical conductor,
An antenna coil, wherein the good conductor is provided in the middle of the conductive paste or in close contact with at least a part of the conductive paste . The antenna coil according to claim 1, wherein
The antenna coil, wherein the good conductor has a volume resistivity lower than that of the conductive paste. The antenna coil according to claim 1, wherein
An antenna coil , wherein the jumper portion is composed of the conductive paste and the good conductor, and the resistivity of the entire jumper portion is lowered . A card substrate and an antenna coil that is wound a plurality of times within the surface of the card substrate and connected at both ends thereof by jumpers, and transmits information in a non-contact state using the induction electromagnetic field as a transmission medium by the antenna coil. In a contactless card that
The non-contact type card | curd using the antenna coil of any one of Claim 1 thru | or 3 as said antenna coil.

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